CN112428295A - Pneumatic safety interlock - Google Patents

Abstract

A robotic tool changer ensures intrinsically safe decoupling operation by providing pneumatic fluid only to a decoupling port of a pneumatic coupling mechanism with the tool changer seated on and properly aligned with a tool holder. Pneumatic fluid for decoupling the pneumatic coupling mechanism is directed from the air source to the tool holder. A through-channel in the tool holder returns pneumatic fluid to a pneumatic path in the tool changer to a decoupling port of the pneumatic coupling mechanism. Thus, the tool changer must sit on the tool rack so that the decoupling port receives pneumatic fluid for operation. In addition, a safety coupling is inserted in the pneumatic path between the tool holder and the coupling port. The safety coupling requires that the tool changer be seated on the tool rack and properly aligned with the tool rack to enable the flow of pneumatic fluid that would otherwise be vented to atmosphere.

Description

Pneumatic safety interlock

Cross Reference to Related Applications

This application claims the benefit of the following patent applications: us patent application No.16/550928 filed on 26.8.2019, the entire contents of which are incorporated herein by reference.

Technical Field

The present invention relates generally to robotics, and in particular to intrinsically safe robotic tool changers that receive power to decouple from a tool rack.

Background

Industrial robots have become an indispensable part of modern manufacturing industry. Whether transferring semiconductor wafers from one process chamber to another in a clean room or cutting and welding steel on the floor of an automotive manufacturing facility, robots perform unwieldy many manufacturing tasks in harsh environments with high precision and repeatability.

In many robotic manufacturing applications, it is cost effective to utilize a relatively versatile robotic arm to accomplish various tasks. For example, in automotive manufacturing applications, a robotic arm may be used to cut, grind, or otherwise shape metal parts during one production stage and perform various welding tasks in another stage. Different welding tool geometries may advantageously be coordinated with a particular robotic arm to perform welding tasks at different locations or in different orientations.

In these applications, tool changers are used to match different robot tools to the robot. One half of the tool changer, called the master unit, is permanently fixed to the robot arm. The other half, called the tool unit, is fixed to each robot tool available to the robot. The various robotic tools available to the robot are typically stored within the range of motion of the robotic arm in a tool holder that is sized and shaped to securely hold each tool when not in use. When the robotic arm positions the master unit on the end of the robotic arm adjacent to a tool unit connected to a desired robotic tool located in the tool rack, a coupling mechanism is actuated that mechanically locks the master unit and the tool unit together, thereby securing the robotic tool to the end of the robotic arm. Thus, the tool changer provides a consistent mechanical interface between the robotic arm and the various robotic tools. The tool changer may also transfer utilities to the robotic tool.

The robotic tool may require utilities such as electrical current, pneumatic pressure, hydraulic fluid, cooling water, electronic or optical data signals, etc. for operation. When the same robot uses many different tools-requiring different utilities-each time the tool is replaced, the utility connection must be manually established. To eliminate this process, an important function of the robotic tool changer is to provide a utility transfer module. Such a module can be attached to standardized locations on the main unit and the tool unit of the robotic tool changer. The modules include mating terminals, valve connections, electrical connectors, etc. so that the selected tool can utilize the utility when the selected tool is coupled to the robotic arm. Many tool changers include one or more standard sized "ledges" around their periphery to which various utilities may be connected via modules as desired. Tool changers and utility transfer modules are well known in the robotics art and are commercially available from, for example, the assignee (ATI Industrial Automation of Apex, north carolina).

As mentioned above, when not in use, each robotic tool is stored in a dedicated rack or tool rack within the operating range of the robotic arm. The robot arm controller software "remembers" where each robot tool is located and each robot tool returns to exactly the same position in its tool holder before decoupling of the tool changer. Similarly, the robot arm controller software "knows" exactly where the next desired robot tool is stored, and it positions (on the robot arm) the master unit of the tool changer adjacent to the tool unit (on the desired robot tool), and then actuates the tool changer to couple the next robot tool to the robot arm.

In a manufacturing environment, safety is the most important issue. Various workplace regulations govern the use of large industrial robots to which heavy robot tools are attached. For example, ISO13849, "safety-related components of mechanical safety-control systems" defines five Performance Levels (PL), denoted a to E. Performance level d (pld) is a mandatory requirement for many industrial robot applications, requiring a probability of less than 106 dangerous failures per hour, i.e. at least one million hours of operation between dangerous failures.

From the point of view of the robotic tool changer and its function, the most likely dangerous failure is the inadvertent decoupling of the master unit and the tool unit, allowing the robotic tool to fall freely off the robotic arm. This risk has long been recognized, and the most advanced robotic tool changer designs minimize the risk. For example, if positive coupling power (e.g., pneumatic pressure) is lost during operation, a "fail-safe" design may ensure that the tool does not become detached from the robotic arm. See, for example, U.S. patent nos. 7,252,453 and 8,005,570 assigned to ATI industrial automation (the assignee of the present application).

In addition to preventing accidental drops of robotic tools due to pressure loss, ATI industrial automation also addresses software deficiencies or the safety hazards of inadvertent commands that present valid "decoupled" commands to robotic tool changers at the wrong time (e.g., when the tool is in use). Us patent No.6,840,895 describes an interlock circuit that prevents even a valid "open" command from reaching the coupling mechanism of the robotic tool changer if the tool side safety interlock is not engaged. The tool side safety interlock is automatically engaged whenever the robotic tool is placed in its tool rack, and disengaged whenever the robotic tool is removed from the tool rack.

The interlock circuit may effectively prevent inadvertent decoupling of the robotic tool changer. However, in order to meet very stringent safety standards, such as ISO13849 PLD, critical components (circuit components, pneumatic valves, etc.) must be redundant. Furthermore, to ensure that the redundancy designed is not phantom, for example if one of the redundant circuits fails, a monitoring device must be added that constantly ensures that all critical elements are not only present, but are fully operational and functional. Such redundancy and monitoring systems add to the cost, complexity, and weight of the robotic tool changer.

This background section of the document is provided to place embodiments of the invention in a technical and operational environment to assist those skilled in the art in understanding the scope and utility of the present invention. Unless explicitly identified as such, statements herein are merely included in the background section and are not admitted to be prior art.

Disclosure of Invention

The following presents a simplified summary of the disclosure in order to provide a basic understanding to those skilled in the art. This summary is not an extensive overview of the disclosure and is not intended to identify key/critical elements of the embodiments or to delineate the scope of the invention. Its sole purpose is to present some concepts disclosed herein in a simplified form as a prelude to the more detailed description that is presented later.

According to one or more embodiments described and claimed herein, a robotic tool changer ensures intrinsically safe operation by decoupling the power sources for "coupled" and "decoupled" operation of its coupling mechanisms. The power for the decoupling operation is only available when the attached robotic tool is safely placed in its tool holder. Once the robotic tool leaves the tool rack, no power is supplied to the coupling mechanism of the robotic tool changer to decouple the robotic tool from the robotic arm. Thus, even if the software erroneously issues a decoupling signal, or otherwise initiates a decoupling operation, the robotic tool may not be inadvertently disengaged from the robotic arm. Furthermore, since the design is inherently safe, no interlock circuits, redundancy of such circuits, and extensive and complex monitoring circuitry necessary to ensure their correct operation are required.

One embodiment relates to a robotic tool changer. The robotic tool changer includes a main unit assembly operably connected to a robot, and a tool unit assembly operably connected to a robotic tool. A coupling mechanism is disposed in one of the main unit assembly and the tool unit assembly and is operable to selectively couple the main unit assembly and the tool unit assembly together. The coupling mechanism requires a first power source to couple and a separate second power source to decouple. The robotic tool changer receives the second power only from the tool rack operable to securely hold the robotic tool. Thus, the decoupling power is only available when the attached robotic tool is safely arranged in its tool holder.

Another embodiment relates to an intrinsically safe method of selectively attaching a robotic tool disposed in a tool holder to a robot. The main unit assembly of the tool changer is attached to the robot and the tool unit assembly of the tool changer is attached to said robot tool. One of the main unit assembly and the tool unit assembly includes a coupling mechanism operable to selectively couple and decouple the main unit assembly and the tool unit assembly to each other. A robot is positioned adjacent the robot tool such that the main unit assembly and the tool unit assembly abut. The coupling mechanism is driven with power from a first source to couple the main unit assembly and the tool unit assembly together. The robotic tool is removed from the tool holder by operation of the robot. The robot tool is returned to the tool holder by operation of the robot. Driving the coupling mechanism with power from a second source associated with the tool holder decouples the main unit assembly and the tool unit assembly. When the robotic tool is not disposed in the tool rack, power from a second source is not available to drive the coupling mechanism to decouple the main unit assembly and the tool unit assembly.

In some embodiments, the coupling mechanism includes a pneumatically actuated piston, for example, operating similarly to those described in U.S. patents 7,252,453 and 8,005,570. The piston has a coupling port to receive pneumatic fluid from a first supply, which is operable to move the piston to couple the main unit assembly and the tool unit assembly together. The term "forward" is used herein to describe the movement of the piston in the direction coupling the main unit and the tool unit. The coupling port directs the pneumatic fluid to the space behind the piston therein, referred to herein as the coupling chamber.

The piston has a separate decoupling port to receive pneumatic fluid from a separate supply different from the first supply (or at least to the piston along a different path). Pneumatic fluid at the decoupling port is operable to move the piston, thereby decoupling the main unit and the tool unit from each other. The term "rearward" is used herein to describe the movement of the piston in a direction that decouples the main unit and the tool unit. The space in front of the piston into which the decoupling port directs the pneumatic fluid is referred to herein as a decoupling cavity. The pneumatic fluid for the decoupling port flows only from the tool holder to the robotic tool changer through a pneumatic coupling on or attached to the tool unit, which mates with a corresponding pneumatic coupling on the tool holder when an attached robotic tool is safely disposed in the tool holder.

When the robotic tool is attached to a robotic arm and removed from its tool holder, there is no pneumatic pressure available at the decoupling port to move the piston backwards, thereby decoupling the tool unit from the master unit. Thus, the robotic tool changer of embodiments of the present invention is inherently safe, and will not inadvertently decouple the robotic tool from the robotic arm unless the robotic tool is disposed in its tool rack. In various embodiments, the flow control of the pneumatic fluid, e.g. via valves and pneumatic flow conduits, is distributed in various ways, each having specific advantages with respect to cost, complexity, ease of maintenance, etc. However, all embodiments share the design feature that the attached robotic tool has to be placed in its tool rack to enable the robotic tool changer to decouple the tool unit from the master unit (and thus remove the robotic tool from the robotic arm).

The various embodiments described and claimed herein all have inherent safety features with decoupling the pneumatic fluid required for a tool changer supplied or directed through the tool rack so that it is only available when the robotic tool is disposed in the tool rack.

In a first embodiment, the tool holder supplies pneumatic fluid, a decoupling control valve is associated with the tool unit, and a coupling control valve is associated with the main unit.

In a second embodiment, the tool holder supplies pneumatic fluid and a decoupling control valve is associated with the tool holder, receiving control signals from the robot.

In a third embodiment, a single robotic pneumatic fluid supply provides pneumatic fluid for both coupling and decoupling. Decoupling pneumatic fluid is delivered through the tool unit to bridges on the tool rack and returned through the tool unit to the main unit (thus, not available unless the robotic tool is disposed in the tool rack).

In a fourth embodiment, the tool holder supplies pneumatic fluid and a decoupling control valve is associated with the tool holder, receiving control signals from the robot. The robot also supplies pneumatic fluid, and a coupling control valve is associated with the robot. Both the main unit and the tool unit provide pneumatic fluid communication.

In a fifth embodiment, the tool holder supplies pneumatic fluid at a first pressure. There is no decoupling control valve. The robot supplies pneumatic fluid at a second pressure higher than the first pressure, and a coupling control valve is associated with said main unit.

The coupling control valves in the first to fifth embodiments and the decoupling control valves in the first to fourth embodiments are preferably three-way solenoid valves. In the sixth embodiment, a single four-way solenoid-operated valve controls pneumatic fluid flow for both coupling and decoupling operation. As in the third embodiment, pneumatic fluid is led through the tool holder and therefore cannot be used for decoupling operations when an attached robot tool is removed from the tool holder.

In a seventh embodiment, a single spring-loaded push button actuated control valve is interposed in the pneumatic path from the air source to the tool holder. A safety coupling is interposed in a pneumatic path from the tool rack to a decoupling port of the pneumatic coupling mechanism. The safety coupling ensures that the tool changer sits on the tool rack and is properly aligned with the tool rack to effect the transfer of pneumatic fluid (which may otherwise be vented to atmosphere).

Drawings

The present invention now will be described more fully hereinafter with reference to the accompanying drawings, in which embodiments of the invention are shown. However, the present invention should not be construed as being limited to the embodiments set forth herein. Rather, these embodiments are provided so that this disclosure will be thorough and complete, and will fully convey the scope of the invention to those skilled in the art. Like reference numerals refer to like elements throughout the specification.

Fig. 1 is a perspective view of a tool changer.

Fig. 2 is a perspective view of the main unit pneumatic module.

FIG. 3 is a perspective view of the tool unit pneumatic module showing the valves inside.

Fig. 4A is a pneumatic schematic of the tool side of the tool changer in the tool rack according to the first embodiment.

Fig. 4B is a pneumatic schematic diagram of the tool changer depicting a coupling operation according to the first embodiment.

Fig. 4C is a pneumatic schematic of the tool changer depicting the decoupling operation according to the first embodiment.

Fig. 4D is a pneumatic schematic diagram of the tool changer when the main unit and the tool unit are separated according to the first embodiment.

Fig. 5A is a pneumatic schematic of the tool side of the tool changer in the tool rack during a coupling operation according to the second embodiment.

Fig. 5B is a pneumatic schematic diagram of a tool changer depicting a coupling operation according to a second embodiment.

FIG. 5C is a perspective view of the tool unit pneumatic module showing the pneumatic through channels inside.

Fig. 5D is a pneumatic schematic of the tool side of the tool changer in the tool rack during a decoupling operation according to the second embodiment.

Fig. 5E is a pneumatic schematic diagram of a tool changer depicting a decoupling operation according to a second embodiment.

Fig. 6A is a pneumatic schematic of the tool side of the tool changer in the tool rack according to the third embodiment.

Fig. 6B is a perspective view of a tool unit attachment according to a third embodiment.

Fig. 6C is a perspective view of a tool rack attachment including a bridge conduit according to a third embodiment.

Fig. 6D is a perspective view of the accessory of fig. 6B and 6C mounted on a tool holder according to a third embodiment.

Fig. 6E is a pneumatic schematic diagram of a tool changer depicting a coupling operation according to a third embodiment.

Fig. 6F is a pneumatic schematic of the tool changer depicting a decoupling operation according to a third embodiment.

Fig. 7A is a pneumatic schematic of the tool side of the tool changer in the tool rack during a coupling operation according to a fourth embodiment.

Fig. 7B is a pneumatic schematic diagram of a tool changer depicting a coupling operation according to a fourth embodiment.

Fig. 7C is a pneumatic schematic of the tool side of the tool changer in the tool rack during a decoupling operation according to the fourth embodiment.

Fig. 7D is a pneumatic schematic of the tool changer depicting the decoupling operation according to the fourth embodiment.

Fig. 8A is a pneumatic schematic of the tool side of the tool changer in the tool rack according to the fifth embodiment.

Fig. 8B is a pneumatic schematic diagram of a tool changer depicting a coupling operation according to a fifth embodiment.

Fig. 8C is a pneumatic schematic of the tool changer depicting the decoupling operation according to the fifth embodiment.

Fig. 8D is a pneumatic schematic view of the tool changer when the main unit and the tool unit are separated according to the fifth embodiment.

Fig. 9A is a pneumatic schematic of the tool side of the tool changer in the tool rack according to the sixth embodiment.

Fig. 9B is a pneumatic schematic diagram of a tool changer depicting a coupling operation according to a sixth embodiment.

Fig. 9C is a pneumatic schematic of the tool changer depicting the decoupling operation according to the sixth embodiment.

Fig. 9D is a pneumatic schematic of the tool changer when removing the robotic tool from the tool holder according to the sixth embodiment.

Fig. 10 is a flow chart of an intrinsically safe method of attaching a robotic tool to a robot.

Fig. 11 is a pneumatic schematic of a tool changer and tool rack according to a seventh embodiment.

Fig. 12A is a pneumatic schematic of a seventh embodiment in which the robot is decoupled from the tool disposed in the tool holder.

Fig. 12B is a pneumatic schematic view of the seventh embodiment, in which the main unit assembly abuts the tool unit assembly and is ready for coupling.

Fig. 12C is a pneumatic schematic diagram of the seventh embodiment, in which the main unit assembly is coupled to the tool unit in the tool rack.

Fig. 12D is a pneumatic schematic of the seventh embodiment with the main unit assembly and the tool unit assembly (and the attached tools) removed from the tool rack.

Fig. 12E is a pneumatic schematic of the seventh embodiment with the tool returned to the tool rack and the master unit assembly decoupled from the tool unit assembly.

Fig. 12F is a pneumatic schematic of a seventh embodiment in which the robot is decoupled from the tool disposed in the tool holder.

Fig. 13 is a perspective view of a portion of a tool coupler.

FIG. 14 is a cross-sectional view of the main pneumatic module and the tool pneumatic module.

Fig. 15 is a flow chart of an intrinsically safe method of detaching a robotic tool from a robot.

Detailed Description

For simplicity and illustrative purposes, the present invention is described by referring mainly to exemplary embodiments thereof. In the following description, numerous specific details are set forth in order to provide a thorough understanding of the present invention. It will be apparent, however, to one skilled in the art that the present invention may be practiced without limitation to these specific details. In this specification, well-known methods and structures have not been described in detail so as not to unnecessarily obscure embodiments of the invention.

Fig. 1 illustrates one embodiment of a robotic tool changer 10. The tool changer 10 includes a main unit 12 operatively secured to a robotic arm (not shown), and a tool unit 14 operatively secured to a robotic tool (not shown). The main unit 12 includes a coupling mechanism 16 protruding from its front surface, a tapered locating pin 18, and a ledge 20 formed on each of the four sides for attaching utility traffic modules. Tool unit 14 includes a recess 22 for receiving coupling mechanism 16 and a tapered locating hole 24 for receiving locating pin 18. The tool unit 14 also includes a ledge 20 formed on each of the four sides for attaching utility traffic modules.

In the illustrated embodiment, the coupling mechanism 16 provided in the main unit 12 operates by projecting balls radially outwardly through concentrically spaced apertures. When the main unit 12 is brought into contact with the tool unit 14 such that the coupling mechanism 16 is disposed within the recess 22, the balls contact and press against the annular surface in the recess 22 in the tool unit 14, thereby coupling the main unit 12 and the tool unit 14 together. These balls are urged outwardly by the angled cam surface of the pneumatically actuated piston. As the piston moves forward along the longitudinal axis towards the tool unit, the balls are pushed outward and into contact with the annular surface in the tool unit 14. To decouple the main unit 12 and the tool unit 14, the piston is retracted in a rearward direction (away from the tool unit) along the longitudinal axis. The angled cam surface then disengages the balls, allowing the balls to retract into the holes, and allowing the main unit 12 and tool unit 14 to disengage and disengage. Further details of the pneumatically actuated coupling mechanism of a robotic tool changer can be found in us patents 7,252,453 and 8,005,570.

From a safety point of view, the movement of the piston is a primary consideration. Thus, the piston is designed and implemented to require a separate power source (in this case a pressurized pneumatic fluid supply) to drive the piston in each direction, i.e., to couple and decouple the main unit 12 and the tool unit 14. Further, in some embodiments, actuation of pneumatic valves controlling pneumatic fluid flow on each side of the piston drive mechanism must be coordinated. For example, in the coupled state, pressurized air remains in the coupling chamber (behind the piston), forcing the piston to its maximum extent along the longitudinal axis in the forward direction. During this time, the decoupling chamber of the piston is open to ambient air pressure. Then, to decouple the tool changer 10, not only must pneumatic fluid be applied to the decoupling chamber (the front side of the piston) through the decoupling port to drive the piston along the longitudinal axis in the rearward direction, but the coupling chamber formed at the rear of the piston must be vented to ambient air pressure to allow the piston to retract.

Similarly, to again couple the main unit 12 to the same or a different tool 14, pneumatic fluid is applied to the coupling port, pressurized air is applied to the coupling chamber to drive the piston forward, and the pressure in the decoupling chamber must also be released to allow the piston to move forward. Therefore, in addition to the ports supplied by the separate pneumatic fluid supply means (or pneumatic fluid flow path), a three-way pneumatic valve is required to supply pneumatic fluid to each port of the piston.

In some embodiments described herein, the main unit pneumatic module 26 is secured to one of the ledges 20 of the main unit 12. The master unit pneumatic module 26 itself includes a mounting ledge 20 opposite the master unit 12, allowing a utility traffic module 28 to be attached thereto. Thus, the master unit pneumatic module 26 provides inherently safe coupling mechanism 16 actuation according to embodiments of the present invention without reducing utility traffic module capacity of the tool changer 10. In other embodiments (not shown), the functionality of the main unit pneumatic module 26 may be built into the main unit 12 without the need for an external module 26. Fig. 2 shows an independent view of the main unit pneumatic module 26.

The main unit pneumatic module 26 includes a pneumatic coupling port 30. The coupling port 30 is positioned to mate with a corresponding pneumatic coupling port on the tool unit pneumatic module 36 when the modules 26, 36 are abutted. When an attached tool is disposed in the tool rack, the pneumatic coupling 30 transfers pneumatic fluid supplied by or through the tool rack to the tool unit pneumatic module 36. Inside the main unit pneumatic module 26, a pneumatic flow conduit (not shown) connects the pneumatic coupling port 30 in pneumatic fluid flow relationship to a decoupling port of a pneumatically actuated piston 56 of the coupling mechanism 16. In some embodiments, the main unit pneumatic module 26 includes an electrical connector 32, the electrical connector 32 being positioned to mate with a corresponding electrical connector on some embodiments of the tool unit pneumatic module 36. In these embodiments, the electrical connector 32 transmits at least one decoupling command to the tool unit pneumatic module 36. The main unit pneumatic module 26 may also include a pneumatic fluid connector 34 that is operatively connected to a pneumatic fluid supply on the robotic arm.

In most embodiments disclosed herein, the main unit pneumatic module 26 includes a three-way solenoid valve (not shown in fig. 2), which is referred to herein as a coupling control valve. The coupling control valve is operable to control the supply of pneumatic fluid from the robot (via the pneumatic fluid connector 34) to the coupling port of the pneumatically actuated piston 56 of the coupling mechanism 16 during a coupling operation, and also to exhaust air from the coupling chamber of the piston 56 during a decoupling operation. The main unit pneumatic module 26 also includes the aforementioned pneumatic flow conduit (not shown) that connects the pneumatic coupling port 30 (which receives pneumatic fluid from the tool rack 48 via the tool unit pneumatic module 36) to the decoupling port of the pneumatically actuated piston of the coupling mechanism 16.

As shown in fig. 1, the tool unit pneumatic module 36 is secured to one of the ledges 20 of the tool unit 14. The tool unit pneumatic module 36 itself includes a mounting ledge 20 opposite the tool unit 12, allowing a utility traffic module 38 to be attached thereto. Thus, the tool unit pneumatic module 36 provides inherently safe coupling mechanism 16 actuation according to embodiments of the present invention without reducing utility traffic module capacity of the tool changer 10. In another embodiment (not shown), the functionality of the tool unit pneumatic module 36 may be built into the tool unit 12 without the need for an external module 36. Fig. 3 shows an isolated view of the tool unit pneumatic module 36.

The tool unit pneumatic module 36 also includes a pneumatic coupling port 30. The coupling port 30 is positioned to mate with a corresponding pneumatic coupling port on the main unit pneumatic module 36 when the modules 26, 26 are abutted. When the attached tool is disposed in the tool rack, the pneumatic coupling 30 transfers pneumatic fluid supplied by or through the tool rack to the main unit pneumatic module 26. In some embodiments, as shown in phantom in fig. 3, inside the tool unit pneumatic module 36 is a three-way solenoid valve 44, referred to herein as a decoupling control valve. The decoupling control valve is operable to control the supply of pneumatic fluid from the tool holder to the decoupling port of the pneumatically actuated piston 56 of the coupling mechanism 16 (via the master unit pneumatic module 26) in a decoupling operation, and to exhaust air from the decoupling chamber of the piston 56 in a coupling operation. The valve 44 operates in response to a decoupling command transmitted from the main unit 12 to the tool unit pneumatic module 36 via the electrical connector 32, the electrical connector 32 being positioned to mate with a corresponding electrical connector 32 on the main unit pneumatic module 26. The tool unit pneumatic module 36 also includes a pneumatic fluid connector 46 that is operatively connected to a pneumatic fluid supply on or through the tool rack.

Various embodiments of the present invention are disclosed and claimed herein. In all of these embodiments, a coupling control pneumatic valve controls the pneumatic fluid flow that drives the coupling actuation of the coupling mechanism 16. In most embodiments, a decoupled control pneumatic valve will control the pneumatic fluid flow that drives the decoupled actuation. In all these embodiments, the intrinsically safe operation of the tool changer 10 is ensured by the fact that the pneumatic fluid, which operatively drives the decoupled actuation, originates from or passes through the tool holder, where the robotic tool can be safely positioned. The decoupling pneumatic fluid available to drive the coupling mechanism 16 is only brought to the decoupling position when the robotic tool is in the tool holder. Once the robot removes the robotic tool from the tool rack, decoupling of the coupling mechanism 16 is physically impossible even if the control software issues a decoupling control signal (or otherwise attempts to initiate a decoupling operation). The various embodiments disclosed and claimed herein differ in the distribution of coupling and decoupling the control pneumatic valve and the pneumatic fluid source, the control signal distribution, and the relative pneumatic pressure between the different supplies. Different configurations of the main unit pneumatic module 26 and the tool unit pneumatic module 36 are optimized for different embodiments.

Detailed description of the first embodiment

Fig. 4A to 4D show a first embodiment in which a coupling control valve is provided in the main unit pneumatic module, a decoupling control valve is provided in the tool unit pneumatic module, and a source of decoupling pneumatic fluid is associated with the tool rack.

Fig. 4A shows the tool unit 14 and the tool unit pneumatic module 36 (along with attached robotic tools, not shown) disposed in the tool rack 48. The tool unit pneumatic module 36 is connected to a tool rack pneumatic fluid supply 52 via a tool rack pneumatic coupling 50. The pneumatic coupling 50 includes a check valve on the side of the tool holder to prevent the flow of pneumatic fluid when the robotic tool is removed from the tool holder 48. When the attached robotic tool is safely disposed within the tool rack 48, the pneumatic coupling 50 supplies pneumatic fluid from the tool rack pneumatic fluid supply 52 to the tool unit pneumatic module 36.

Fig. 4B is a schematic pneumatic diagram illustrating the relevant pneumatic fluid and control signal flow when the tool changer main unit 12 is coupled to the tool unit 14. The master cells 12 generate a coupling signal and a decoupling signal, which may for example comprise a positive or a negative voltage with respect to a 0V reference voltage. Alternatively, the coupling and decoupling signals may comprise digital values, optical signals, wireless signals, or any other means of sending control commands known in the art. In one embodiment, the coupling and decoupling signals comprise a positive voltage relative to the 0V reference signal, which is operable to energize the solenoid on the three- way solenoid valve 26, 36 when the signal is asserted, and 0V when the signal is de-asserted. The coupling and decoupling signals are mutually exclusive, that is, the two signals are never issued simultaneously.

When the coupling signal is issued, the coupling control valve 54 is configured to transfer pneumatic fluid from a pneumatic fluid supply 58 on the robot to a coupling port of a pneumatically actuated piston 56 of the coupling mechanism 16. The decoupling port of the piston 56 is connected to the pneumatic coupling 30 via the above-mentioned pneumatic flow conduit 60 in the main unit pneumatic module 26. This allows air to flow from the decoupling chamber of the piston 56 to the decoupling control valve 44. The decoupling signal transmitted to the decoupling control valve 44 via the electrical connector 32 is deactivated. Because the decoupling signal is deactivated, the decoupling control valve 44 is in its default state, connecting the pneumatic coupling 30 to the exhaust port. In this configuration, the piston 56 is driven forward (to the left as viewed in fig. 4B) to couple the main unit 12 and the tool unit 14 together. The piston 56 is allowed to move in the forward direction by air in the decoupling chamber being discharged through the decoupling control valve 44.

Once the main unit 12 is coupled to the tool unit 14 and the robot removes the attached robot tool from the tool rack 48, the units 12, 14 cannot be decoupled. The pneumatic fluid source 58 on the robot continues to provide positive pressure to the coupling port of the piston 56 through the coupling control valve 54, forcing the piston 56 forward or to the coupled position. Crucially, there is no source of pneumatic fluid connected to the decoupling port of the piston 56 to drive it back or towards the decoupled position (even if present, air trapped in the coupling chamber of the piston 56 does not have a vent path and will resist movement of the piston 56 in that direction).

Fig. 4C depicts the decoupling operation. Once the robotic tool is safely set in the tool rack 48 and the main unit 12 receives notification of this fact, the main unit 12 and the tool unit 14 may be decoupled. The main unit 12 uncouples the command and issues a decouple command, which causes the decoupling control valve 44 to connect the tool holder pneumatic fluid source 52 with the pneumatic coupling 30. A pneumatic flow conduit 60 in the main unit pneumatic module 26 delivers pneumatic fluid to the decoupling port of the pneumatic actuator piston 56. At the same time, the decoupling command causes the coupling control valve 54 to direct the air exhaust from the coupling chamber of the piston 56. These two valve settings allow the pneumatic fluid supplied by the tool rack 48 to drive the piston 56 rearwardly, or to a decoupling position, allowing the main unit 12 and the tool unit 14 to be decoupled. The robot may then move with the main unit 12 to retrieve the different robot tools to safely dispose the robot tools in the tool rack 48.

Note that the main unit 12 needs to be aware that the robot tool is set in the tool rack 48. Many industrial robot systems have generated such "tool in place" signals as part of one or more safety interconnections. The "tool in place" signal may be generated by a switch or proximity sensor on the tool rack 48, on the tool unit 14, on the robotic tool, etc. The signal may be sent to the main unit 12 through mating contacts on the tool unit 14, or alternatively may be transmitted from the robot to the main unit 12.

Fig. 4D shows the decoupled state when the robot has stowed the robot tool in the tool rack 48 and moved the main unit 12 away from the tool unit 14. The decoupling control valve 44 is in a default state (no decoupling signal), blocking the tool holder pneumatic fluid and venting the pneumatic coupling 30. The coupling control valve 54 blocks the robot pneumatic fluid and exhausts air in the coupling chamber of the piston 56. Note that the coupling control valve 54 is of a double solenoid type. This avoids the main unit 12 automatically coupling in the event of a loss of power, as would occur if the coupling control valve 54 were a "spring-back" type valve with only one solenoid. In this case, the main unit 12 will not be able to be coupled to the tool unit 14 without manually reconfiguring the piston 56. By using a dual solenoid type valve 54, the main unit 12 will only couple when the coupling control signal is active, which only occurs when the main unit 12 is in proximity to and ready to couple with the tool unit 14.

The first embodiment is a direct embodiment of the inventive concept to make the robotic tool changer 10 inherently safe by providing decoupled power only when an attached robotic tool is safely disposed in the tool rack. To the greatest extent possible, this embodiment encompasses all of the functions within tool changer 10. Since the robot pneumatic fluid supply 58 is required for the operation of any pneumatically actuated tool changer, the only modification required at the utility where the robot is deployed is to provide the tool holder pneumatic fluid supply 52 and the tool holder pneumatic coupling 50. Thus, the first embodiment may be particularly advantageous where minimal modifications to the utility are required.

Detailed description of the second embodiment

Fig. 5A-5E illustrate a second embodiment in which a coupling control valve is provided in the main unit pneumatic module, a decoupling control valve is provided on or otherwise associated with the tool rack, and a source of decoupling pneumatic fluid is associated with the tool rack.

Fig. 5A and 5B illustrate a coupling operation in which the tool holder pneumatic fluid supply 52 provides pneumatic fluid to a three-way solenoid valve decoupling control valve 62, in this embodiment, the three-way solenoid valve decoupling control valve 62 is associated with the tool holder 48. In this embodiment, the decoupling control valve 62 receives a decoupling command from the robot. As in the first embodiment, when an attached robotic tool is disposed in the tool rack 48, the tool unit pneumatic module 36 is connected to the tool rack pneumatic fluid via a pneumatic coupling 50.

Referring to fig. 5B, the main unit 12 and the main unit pneumatic module 26 are the same as described above with respect to the first embodiment. In this second embodiment, the tool unit pneumatic module 36 does not include a valve or receive a control signal, but rather includes a pneumatic through-conduit 64 connecting the pneumatic coupling 30 to the tool rack pneumatic coupling 50. Fig. 5C is a perspective view of this embodiment of the tool unit pneumatic module 36. In this embodiment, the tool unit pneumatic module 36 has the same physical dimensions as the first embodiment (see fig. 3); however, the decoupling control valve 44 is replaced by a pneumatic pass-through conduit 64 (shown in phantom). In addition, this embodiment of the tool unit pneumatic module 36 does not include a signal connection to the main unit pneumatic module 26.

In the second embodiment, the coupling operates similarly to the coupling of the first embodiment described above. When the coupling signal is asserted, the coupling control valve 54 is configured to communicate pneumatic fluid from the robotic pneumatic fluid supply 58 to the coupling port of the pneumatically actuated piston 56. The decoupling port of the piston 56 is connected to the pneumatic coupling 30 via a pneumatic flow conduit 60 in the main unit pneumatic module 26. This allows pneumatic fluid from the decoupling chamber of the piston 56 to flow through the pneumatic through-conduit 64 and the tool rack pneumatic coupling 50 in the tool unit pneumatic module 36 to the decoupling control valve 62. The decoupling signal transmitted by the robot to the decoupling control valve 62 is deactivated. Because the decoupling signal is de-asserted, the decoupling control valve 62 is in its default state, connecting the tool rack pneumatic coupling 50 to the exhaust port. In this configuration, the piston 56 is driven forward to couple the main unit 12 and the tool unit 14 together. The piston 56 is allowed to move in the first direction by venting air in the decoupling chamber through the decoupling control valve 62.

Once the main unit 12 is coupled to the tool unit 14 and the robot removes the attached robot tool from the tool rack 48, the units 12, 14 cannot be decoupled. The robot pneumatic fluid source 58 continues to provide a positive pressure to the coupling port of the piston 56 through the coupling control valve 54, forcing the piston 56 forward or to a coupled position. Crucially, there is no source of pneumatic fluid connected to the decoupling port of the piston 56 to drive the piston 56 backwards towards the decoupled position (even if present, air trapped in the coupling chamber of the piston 56 does not have a vent path and will resist movement of the piston 56 in that direction).

Fig. 5D and 5E describe the decoupling operation. Once the robotic tool is safely set in the tool rack 48 and the main unit 12 receives notification of this fact, the main unit 12 and the tool unit 14 may be decoupled. The master unit 12 uncouples the signal and issues a decoupling signal, which is distributed to the coupling control valve 54 and the robot. The robot relays the decoupling signal (either directly or as a digital command, via a network, or in any other manner) to the decoupling control valve 62. The decoupling signal provided by the robot to the decoupling control valve 62 causes the decoupling control valve 62 to connect the tool holder pneumatic fluid supply 52 to the pneumatic coupling 50. The pneumatic fluid then flows to the tool side pneumatic module 36.

The pneumatic fluid flows through the pneumatic vent conduit 62 in the tool unit pneumatic module 36, through the pneumatic coupling 30 into the main unit pneumatic module 26, and through the pneumatic vent conduit 60 to the decoupling port of the pneumatic actuator piston 56. At the same time, the decoupling command causes the coupling control valve 54 to direct the air exhaust from the coupling port of the piston 56. These two valve settings allow the pneumatic fluid supplied by the tool rack 48 to drive the piston 56 rearwardly, or to a decoupling position, allowing the main unit 12 and the tool unit 14 to be decoupled. The robot may then move with the main unit 12 to retrieve the different robot tools to safely dispose the robot tools in the tool rack 48.

The second embodiment moves the decoupling control valve from the tool changer 10 to the tool rack. The tool unit 14 (and tool unit pneumatic module 36, if separate) is typically permanently mounted on each tool that the robot can use. In a utility where only a subset of the available robotic tools are usable by a given robot and the tools are operable using the same tool rack, the second embodiment reduces costs, maintenance and risks by minimizing the required duplication (replication) of decoupling control valves. Placing the decoupling control valves on the tool rack may also allow for easier inspection, maintenance, or replacement as opposed to disassembling each tool unit pneumatic module 36. In addition, the tool unit pneumatic module 36 is significantly reduced in cost and complexity because it has no pneumatic valves or electrical connections.

Detailed description of the third embodiment

Fig. 6A to 6E show a third embodiment, in which a coupling control valve is provided in the main unit pneumatic module, a decoupling control valve is provided in the tool unit pneumatic module, and the decoupling pneumatic fluid is led through a bridge duct on the tool rack before being led to the coupling mechanism.

Fig. 6A depicts a pneumatic bridge duct 70 on the tool rack 48. The bridge conduit 70 receives pneumatic fluid from the tool unit pneumatic module 36 via the supply pneumatic coupling 68 and directs the pneumatic fluid back to the tool unit activation module 36 via the return pneumatic coupling 72. Both pneumatic couplings 68, 72 engage when the robot positions the attached robot tool within the tool rack 48. Check valves on the tool changer side of the pneumatic couplings 68, 72 prevent leakage of pneumatic fluid when the robotic tool is removed from the tool rack 48.

Fig. 6B shows the attachment of the tool unit pneumatic module 36, presenting supply and return pneumatic couplings 68, 72, respectively, to the tool rack 48. Fig. 6C shows an attachment of the tool rack 48 having mating supply and return pneumatic couplings 68, 72, respectively, connected to a pneumatic bridge conduit 70 inside the attachment. Fig. 6D shows the configuration of these two accessories when the robotic tool is disposed in the tool rack 48 (the tool unit 14, the tool unit pneumatic module 36 and the robotic tool have been omitted from fig. 6D for clarity).

Fig. 6E shows the flow of pneumatic and control signals between the main unit pneumatic module 26 and the tool unit pneumatic module 36. The main unit 12 and the main unit pneumatic module 26 are similar to those described above in relation to the first embodiment, with the addition of a pneumatic through duct 74 connecting the robot pneumatic fluid supply 58 to the second pneumatic coupling port 40. The coupling ports 40 are positioned and operatively mate with corresponding pneumatic coupling ports on the tool unit pneumatic module 36. In this third embodiment, the tool unit 14 and tool unit pneumatic module 36 are also similar to those described above with respect to the first embodiment, with the addition of a second pneumatic coupling port 40 and a pneumatic through conduit 76 connecting the pneumatic coupling 40 to the tool rack supply pneumatic coupling 68.

In this embodiment, when an attached robotic tool is disposed in the tool rack 48, pneumatic fluid flows from the robotic pneumatic fluid supply 58, through the main unit pneumatic module 26 and the tool unit pneumatic module 36, through the supply pneumatic coupling 68, the bridge conduit 70, and the return pneumatic coupling 72 on the tool rack 48, and back to the tool unit pneumatic module 36. From the tool unit pneumatic module 36, pneumatic fluid is selectively directed to the decoupling ports of the pneumatically actuated piston 56, as in the previously described embodiment. Removal of the robotic tool from the tool rack 48 disconnects the pneumatic fluid flow path, thereby not allowing decoupling of the coupling mechanism 16.

In the third embodiment, the coupling operates similarly to the coupling of the first embodiment described above. When the coupling signal is asserted, the coupling control valve 54 is configured to communicate pneumatic fluid from the robotic pneumatic fluid supply 58 to the coupling port of the pneumatically actuated piston 56. The decoupling port of the piston 56 is connected to the pneumatic coupling 30 via a pneumatic flow conduit 60 in the main unit pneumatic module 26. This allows pneumatic fluid from the decoupling chamber of the piston 56 to flow through the pneumatic coupling 30 to the tool unit valve 44. The decoupling signal transmitted to the tool unit valve 44 via the electrical coupling 32 is released. Because the decoupling signal is deactivated, the decoupling control valve 44 is in its default state, connecting the pneumatic coupling 30 to the exhaust port. In this configuration, the piston 56 is driven forward in a first direction to couple the main unit 12 and the tool unit 14 together. The piston 56 is allowed to move in the first direction by venting air in the decoupling chamber through the decoupling control valve 44.

Once the main unit 12 is coupled to the tool unit 14 and the robot removes the attached robot tool from the tool rack 48, the units 12, 14 cannot be decoupled. The robot pneumatic fluid source 58 continues to provide a positive pressure to the coupling port of the piston 56 through the coupling control valve 54, forcing the piston 56 forward or to a coupled position. Critically, since the pneumatic fluid driving the decoupling port of the piston 56 is directed through the bridge 70 on the tool holder 48, once the robotic tool is removed from the tool holder 48, there is no path for the source of pneumatic fluid to be connected to the decoupling port of the piston 56 to drive the piston back toward the decoupled position (even if present, air trapped in the coupling chamber of the piston 56 has no path to vent, and will resist movement of the piston 56 in that direction).

Fig. 6F illustrates the decoupling operation. Once the robotic tool is safely set in the tool rack 48 and the main unit 12 receives notification of this fact, the main unit 12 and the tool unit 14 may be decoupled. The main unit 12 uncouples the coupling signal and issues a decoupling signal, which causes the decoupling control valve 44 to transfer pneumatic fluid from the return coupling 72 of the bridge 70 to the pneumatic coupling 30. A pneumatic flow conduit 60 in the main unit pneumatic module 26 delivers pneumatic fluid to the decoupling port of the piston 56. At the same time, the decoupling command causes the coupling control valve 54 to direct the air exhaust from the coupling port of the piston 56. These two valve arrangements allow pneumatic fluid to be supplied by the robotic pneumatic source 58, but direct the pneumatic fluid through the tool rack 48 to drive the piston 56 rearwardly, or to a decoupling position, allowing the main unit 12 and the tool unit 14 to be decoupled. The robot may then move with the main unit 12 to retrieve the different robot tools to safely dispose the robot tools in the tool rack 48.

The third embodiment uses only a single source of pneumatic fluid for both the coupling and decoupling operations, but achieves an intrinsic safety feature by directing the decoupled pneumatic fluid through the tool holder. As described above, since many robots already provide a pneumatic fluid supply, the third embodiment may require small changes to the utility — only supply and return pneumatic couplings and pneumatic bridge tubing are added to the tool rack. On the other hand, the main unit pneumatic module and the tool unit pneumatic module increase in cost and complexity because they require additional pneumatic through-channels and additional pneumatic couplings.

Detailed description of a fourth embodiment

Fig. 7A to 7D show a fourth embodiment, in which a coupling control valve is associated with the robot, a decoupling control valve is associated with the tool holder, a source of decoupling pneumatic fluid is associated with the tool holder, and both the main unit pneumatic module and the tool unit pneumatic module comprise only pneumatic through-circuits.

Fig. 7A and 7B illustrate the coupling operation. As in the second embodiment described above, the tool holder pneumatic fluid supply 52 provides pneumatic fluid to a three-way solenoid valve decoupling control valve 62 associated with the tool holder 48. The decoupling control valve 62 receives a decoupling command from the robot. As in the second embodiment, when an attached robotic tool is disposed in the tool rack 48, the tool unit pneumatic module 36 is connected to the tool rack pneumatic fluid via a pneumatic coupling 50.

Fig. 7B shows the coupling control valve 76 associated with the robot. In this embodiment, the tool unit pneumatic module 36 is the same as described above with respect to the second embodiment, including a pneumatic through conduit 64, but no valves or control signals. The main unit pneumatic module 26 also does not include valves or control signals and includes two pneumatic through- channels 60 and 78. The pneumatic straight-through duct 60 is as described above in all embodiments; a pneumatic through conduit 78 connects the coupling port of the pneumatically actuated piston 56 to a coupling control valve 77 associated with the robot.

In the fourth embodiment, the coupling operates similarly to the coupling described above, but the coupling control valve 77 is associated with the robot and receives commands from the robot. When the coupling signal is issued, the coupling control valve 77 is configured to transfer pneumatic fluid from the robot pneumatic fluid supply 58 to the coupling port of the pneumatically actuated piston 56 through a pneumatic through-conduit 78 in the main unit pneumatic module 26. The decoupling port of the piston 56 is connected to the pneumatic coupling 30 via a pneumatic flow conduit 60 in the main unit pneumatic module 26. This allows pneumatic fluid from the decoupling chamber of the piston 56 to flow through the pneumatic flow conduit 64 and the tool rack pneumatic coupling 50 in the tool unit pneumatic module 36 to the decoupling control valve 62. The decoupling signal transmitted by the robot to the decoupling control valve 62 is deactivated. Because the decoupling signal is de-asserted, the decoupling control valve 62 is in its default state, connecting the tool rack pneumatic coupling 50 to the exhaust port. In this configuration, the piston 56 is driven forward in a first direction to couple the main unit 12 and the tool unit 14 together. The piston 56 is allowed to move in the first direction by venting air in the decoupling chamber through the decoupling control valve 62.

Once the main unit 12 is coupled to the tool unit 14 and the robot removes the attached robot tool from the tool rack 48, the units 12, 14 cannot be decoupled. The robot pneumatic fluid source 58 continues to provide positive pressure to the coupling port of the piston 56 through the coupling control valve 77, forcing the piston 56 forward or to the coupled position. Crucially, there is no source of pneumatic fluid connected to the decoupling port of the piston 56 to drive the piston 56 backwards towards the decoupled position (even if present, air trapped in the coupling chamber of the piston 56 does not have a vent path and will resist movement of the piston 56 in that direction).

Fig. 7C and 7D show the decoupling operation. Once the robotic tool is safely set in the tool rack 48 (the robot knows this fact), the main unit 12 and the tool unit 14 can be decoupled. The robot uncouples the signal and issues a decoupling signal which is distributed to the coupling control valve 77. The robot relays the decoupling signal (either directly, as a digital command, via a network, or in any other manner) to the decoupling control valve 62. The decoupling signal provided by the robot to the decoupling control valve 62 causes the decoupling control valve 62 to connect the tool holder pneumatic fluid supply 52 with the pneumatic coupling 50. The pneumatic fluid then flows to the tool side pneumatic module 36.

The decoupling pneumatic fluid then flows through the pneumatic vent conduit 62 in the tool unit pneumatic module 36, through the pneumatic coupling 30 into the main unit pneumatic module 26, and through the pneumatic vent conduit 60 to the decoupling port of the pneumatic actuating piston 56. At the same time, the decoupling command causes the coupling control valve 77 to direct the air exhaust from the coupling port of the piston 56. These two valve settings allow the pneumatic fluid supplied by the tool rack 48 to drive the piston 56 rearwardly, or to a decoupling position, allowing the main unit 12 and the tool unit 14 to be decoupled. The robot may then move with the main unit 12 to retrieve the different robot tools to safely dispose the robot tools in the tool rack 48.

The fourth embodiment removes the coupling and decoupling control valves from the tool changer 10 to the utility devices (i.e., the robot and tool rack). This embodiment minimizes the cost and complexity of the main unit pneumatic module and the tool unit pneumatic module, as neither includes any valves or electrical contacts. Therefore, the fourth embodiment is preferable in the case where the cost of the tool changer 10 needs to be minimized.

Detailed description of a fifth embodiment

Fig. 8A to 8D depict a fifth embodiment in which a coupling control valve is provided in the main unit pneumatic module, the decoupling pneumatic fluid supply is associated with the tool holder, and the decoupling control valve is absent.

Fig. 8A shows the tool unit 14 and the tool unit pneumatic module 36 (along with attached robotic tools, not shown) disposed in the tool rack 48. As in the first embodiment, the tool unit pneumatic module 36 is connected to a tool rack pneumatic fluid supply 52 via a pneumatic coupling 50. The tool holder pneumatic fluid supply 52 supplies pneumatic fluid at a first pressure (e.g., between 20-30 psi). The pneumatic coupling 50 includes a check valve on the tool holder side to prevent the flow of pneumatic fluid when the robotic tool is removed from the tool holder 48. When the attached robotic tool is safely disposed within the tool rack 48, the pneumatic coupling 50 supplies pneumatic fluid at a first pressure from the tool rack pneumatic fluid supply 52 to the tool unit pneumatic module 36.

Fig. 8B shows the flow of pneumatic and control signals between the main unit pneumatic module 26 and the tool unit pneumatic module 36 during the coupling operation. The main unit 12 and the main unit pneumatic module 26 are the same as described above in relation to the first and second embodiments. That is, the master unit pneumatic module 26 includes a coupling control valve 54 for receiving pneumatic fluid from the robot pneumatic fluid supply 58 at a second pressure that is greater than the first pressure of the tool holder pneumatic fluid supply 52. For example, the robotic pneumatic fluid supply 58 may supply pneumatic fluid at a pressure greater than 80 psi. The main unit pneumatic module 26 also comprises a pneumatic through duct 60 connecting the decoupling port of the piston 56 to the pneumatic coupling 30. The tool unit 14 and the tool unit pneumatic module 36 are similar to those described above with respect to the second and fourth embodiments. That is, the tool unit pneumatic module 36 includes only the pneumatic pass-through conduit 64 and does not receive any electrical signals. However, in this embodiment, the pneumatic coupling port 30 is a check port operable to prevent the flow of pneumatic fluid when the main unit pneumatic module 26 and the tool unit pneumatic module 36 are separated.

Unlike all previously described embodiments, in the fifth embodiment, the tool changer 10 does not employ a decoupling control valve (whether provided in the tool unit pneumatic module 36 or on the tool rack 48) to selectively direct the decoupling pneumatic fluid to the decoupling port of the piston 56, or alternatively vent the decoupling cavity in the piston 56. Instead, this design relies on a substantial pressure differential between the coupled pneumatic fluid at a second, higher pressure (e.g., >80psi) and the decoupled pneumatic fluid at a first, lower pressure (e.g., 20-30 psi).

The coupling operation is substantially similar to the previously described coupling operation, except that the decoupling chamber of the piston 56 is vented. When the coupling signal is issued, the coupling control valve 54 is configured to transfer pneumatic fluid from the robotic pneumatic fluid supply 58 at the second, higher pressure to the coupling port of the pneumatically actuated piston 56. The decoupling port of the piston 56 is maintained at a lower first pressure by connection to the tool holder pneumatic fluid supply 52 via the pneumatic through conduits 60, 64 and the tool holder pneumatic coupling 50. Due to the pressure differential, the piston 56 will actuate in a forward or first direction by compressing the pneumatic fluid in the decoupling chamber and the pneumatic straight-through conduits 60, 64. The piston 56 will actuate far enough to safely couple the main unit 12 to the tool unit 14. However, since the decoupling chamber of the piston 56 is vented to atmosphere through the tool changer side of the tool holder pneumatic coupling 50, the full locking force of the coupling mechanism 16 is only achieved when the robot removes the robot tool from the tool holder 48.

Once the main unit 12 is coupled to the tool unit 14 and the robot removes the attached robot tool from the tool rack 48, the units 12, 14 cannot be decoupled. The robot pneumatic fluid source 58 continues to provide a second, higher pressure to the coupling port of the piston 56 through the coupling control valve 54, forcing the piston 56 forward or to the coupled position. Crucially, there is no source of pneumatic fluid connected to the decoupling port of the piston 56 to drive the piston 56 backwards towards the decoupled position (even if present, air trapped in the coupling chamber of the piston 56 does not have a vent path and will resist movement of the piston 56 in that direction).

Fig. 8C shows a decoupling operation of the fifth embodiment. Once the robotic tool is safely disposed in the tool rack 48, the main unit 12 and the tool unit 14 may be decoupled. The master unit 12 decouples the coupling signal and issues a decoupling signal. This causes the coupling control valve 54 to vent pressure from the coupling chamber of the piston 56. A tool holder pneumatic fluid supply 52, which provides pneumatic fluid at a lower first pressure, is connected to the decoupling port of the piston 56 via a tool holder pneumatic coupling 50, a pneumatic through-conduit 64, the coupling 30 and a pneumatic through-circuit 60. When the lower first pressure of the tool holder pneumatic fluid supply 52 is insufficient to overcome the higher second pressure of the robot pneumatic fluid supply 58, the decoupling signal at the coupling control valve 54 configures the valve 54 to provide atmospheric pressure to the coupling chamber of the piston 56, thereby allowing the lower first pressure to fully decouple the coupling mechanism 16.

Fig. 8D shows the decoupled state when the robot has stowed the robot tool in the tool rack 48 and moved the main unit 12 away from the tool unit 14. The piston 56 remains in the decoupled position with no pressure applied to the coupled or decoupled ports. The coupling control valve 54 exhausts pressure from the coupling chamber of the piston 56 and pressure from the decoupling chamber of the piston 56 is exhausted to atmosphere via a through-loop 60. With the piston 56 in the decoupled position, the main unit 12 is ready to be coupled to the same or a different tool unit 14.

An important parameter of the fifth embodiment is the pressure difference between the coupling pneumatic fluid and the decoupling pneumatic fluid. The specific values described above, i.e., pneumatic fluid at a first pressure in the range of 20-30psi at the tool holder pneumatic fluid supply 52 and pneumatic fluid at a second pressure greater than 80psi at the robot pneumatic fluid supply 58, are merely representative. These pneumatic pressures provided satisfactory results in the tool changer 10 that has been tested. However, these pressure values are not limiting. Those skilled in the art will readily recognize that the optimal pressure differential (and absolute coupling and decoupling pneumatic fluid pressure values) will vary depending on the design of the pneumatically actuated piston 56 and other system components. The functional requirement for selecting the appropriate pressure differential in any particular embodiment is that, first, sufficient force is generated by the piston 56 to cause the main unit 12 to lock onto the tool unit 14, which tool unit 14 is connected to the heaviest robotic tool that the robot will encounter in a particular environment or production run. Second, the decoupling pneumatic fluid pressure must be sufficient to ensure that the piston 56 will move to the decoupling position in an acceptable amount of time. Given the teachings of the present disclosure and these functional requirements, one skilled in the robotic art can readily determine acceptable coupling and decoupling pneumatic fluid pressures for optimal operation in any given implementation.

The fifth embodiment eliminates the need for a decoupled control valve, thus reducing cost, part count, complexity, and potential points of failure. Furthermore, in the fifth embodiment, the tool unit pneumatic module has minimal cost and complexity, no valves or electrical connections, and only one pneumatic through-channel.

Detailed description of a sixth embodiment

FIGS. 9A-9D illustrate a sixth embodiment in which a single control valve (which is a 4-way dual solenoid valve) controls the flow of coupled and decoupled pneumatic fluid; the tool unit pneumatic module only comprises a pneumatic straight-through pipeline; and de-coupled pneumatic fluid is directed through a bridge conduit in the tool rack.

Fig. 9A shows the tool unit 14 and the tool unit pneumatic module 36 (along with attached robotic tools, not shown) disposed in the tool rack 48. As in the third embodiment, the tool rack 48 includes a supply pneumatic coupling 68, a pneumatic bridge conduit 70, and a return pneumatic coupling 72. However, unlike the third embodiment, the supply and return pneumatic couplings 68, 72 do not include any check valves.

Fig. 9B shows the flow of pneumatic and control signals between the main unit pneumatic module 26 and the tool unit pneumatic module 36 during the coupling operation. The main unit pneumatic module 26 includes a four-way dual solenoid control valve 80 that receives pneumatic fluid (at high pressure, e.g., >80psi) from the robotic pneumatic fluid supply 58. For coupling, the control valve 80 directs pneumatic fluid from the robotic supply 58 to the coupling port of the pneumatically actuated piston 56. The air in the decoupling chamber of the piston 56 is vented to atmosphere. The paths for venting the decoupling chamber air are: the decoupling port from the piston 56 passes through the pneumatic through- channels 60, 62, through the pneumatic bridge channel 70 on the tool holder 48, through the pneumatic through-channel 76, and through the control valve 80 to the exhaust port. The combination of supplying high pressure pneumatic fluid to the coupling port of the piston 56 and venting the decoupling chamber of the piston 56 to atmosphere effectively drives the piston 56 forward and couples the main unit 12 to the tool unit 14.

Fig. 9B describes the decoupling operation. Once the robotic tool is safely disposed in the tool rack 48, the main unit 12 and the tool unit 14 may be decoupled. The main unit 12 uncouples the signal and issues a decoupling signal, both of which are provided to the control valve 80. This configures the control valve 80 to direct pneumatic fluid from the robotic pneumatic fluid supply 58 to the pneumatic coupling 40. The de-coupled pneumatic fluid then flows through the pneumatic through-passage 76 to the tool holder 48. The de-coupled pneumatic fluid then flows through the tool rack supply pneumatic coupling 68, the bridge conduit 70, and the return coupling 72, and returns to the tool unit pneumatic module 36. The decoupling pneumatic fluid then flows through the pneumatic fluid through conduit 62, the pneumatic coupling 30, and through the pneumatic fluid through conduit 60 to the decoupling port of the piston 56. Since this pneumatic fluid is provided by the robotic pneumatic fluid supply 58, it is at the same high pressure (e.g., >80psi) as the pneumatic fluid used in the coupling operation. At the same time, the decoupling command configures the control valve 80 to vent air from the coupling chamber of the piston 56 to atmosphere. The combination of supplying high pressure pneumatic fluid to the decoupling port of the piston 56 via the tool rack 48 and venting the coupling chamber of the piston 56 to atmosphere effectively drives the piston 56 rearwardly and decouples the main unit 12 from the tool unit 14. The robot may then move with the main unit 12 to retrieve the different robot tools to safely dispose the robot tools in the tool rack 48.

Once the main unit 12 is coupled to the tool unit 14 and the robot removes the attached robot tool from the tool rack 48, the units 12, 14 cannot be decoupled. The robot pneumatic fluid source 58 continues to supply high pressure pneumatic fluid through the control valve 80 to the coupling port of the piston 56, forcing the piston 56 forward or to the coupled position. Crucially, no source of pneumatic fluid is connected to the decoupling port of the piston 56 to drive the piston towards the return or decoupling position.

Even in the event that the master unit 12 erroneously issues a decoupling signal, the decoupling pneumatic fluid is vented to atmosphere through the tool unit pneumatic module 36 and is not directed back to the decoupling port of the piston 56. Fig. 9D shows this case. The decoupling signal places the control valve 80 in the state shown in fig. 9C and the robotic pneumatic fluid supply 58 provides the decoupling pneumatic fluid through the coupling 30 and the pneumatic fluid through conduit 76. Since the attached robotic tool is not in the tool rack 80, the pneumatic fluid is vented to atmosphere on the tool changer side of the supply pneumatic fluid coupling 68. Since there is only atmospheric pressure at the return pneumatic fluid coupling 68, this is the pressure that is transmitted through the pneumatic through conduits 62 and 60 and delivered to the decoupling port of the piston 56. Note that the coupling port of the piston 56 is also vented to atmospheric pressure through the control valve 80. Thus, the piston 56 is not actively driven to the coupled or decoupled position. In this case, a failsafe mechanism, such as one or more of the mechanisms disclosed in U.S. patent nos. 7,252,453 or 8,005,570, is used to prevent the main unit 12 and tool unit 14 from decoupling.

The sixth embodiment eliminates the need for a decoupled control valve, thus reducing cost, part count, complexity, and potential points of failure. Full pressure is provided for the coupling and decoupling operations, so there is no difference in the speed of these complementary operations. Furthermore, in the sixth embodiment, the tool unit pneumatic module is low cost and complex, has no valves or electrical connections, and has only two pneumatic through-channels.

Method of attaching an intrinsically safe robotic tool

Fig. 10 illustrates an intrinsically safe method 100 of attaching a robotic tool disposed in a tool holder 48 to a robot. The main unit 12 of the tool changer 10 is attached to the robot and the tool unit 14 of the tool changer 10 is attached to the robot tool. One of the main unit 12 and the tool unit 14 includes a coupling mechanism 16 operable to selectively couple and decouple the main unit 12 and the tool unit 14 to each other. The robot is positioned adjacent the robotic tool such that the main unit 12 and the tool unit 14 mechanically mate (block 102). The coupling mechanism 16 is driven using power from the first source 58 to couple the main unit 12 and the tool unit 14 together (block 104). The robot tool is removed from the tool rack 48 by operation of the robot (block 106). After some tasks are performed with the robotic tool, the robotic tool is returned to the tool rack 48 by operation of the robot (block 108). If the robotic tool is safely disposed in the tool rack 48 (block 110), the coupling mechanism 16 is driven with power from a second source associated with the tool rack 48 to decouple the main unit 12 and the tool unit 14 (block 112). If the robotic tool is not safely disposed in the tool rack 48 (block 110), power from the second source is not available and the main unit 12 and the tool unit 14 cannot be decoupled. In this case, the robotic tool must be returned to the tool rack 48 before the tool changer 10 can be decoupled (block 108).

Detailed description of the seventh embodiment

Fig. 11 shows a seventh embodiment which is similar in some respects to the third embodiment described herein (with reference to fig. 6A-6F) in that the pneumatic fluid driving the decoupling ports of the piston 56 travels in the toolhead 48 in a loop back configuration 70. Thus, the motive force to drive the piston 56 to decouple the tool changer 10 is available only when the attached tool (and thus the tool pneumatic module 36) is safely disposed in the tool rack 48. This seventh embodiment includes additional features that further enhance safety and ensure that the piston 56 does not inadvertently decouple in many possible use cases.

Fig. 11 shows the master unit 12 with the master pneumatic module 26 attached, decoupled from the tool unit 14, with the tool pneumatic module 36 attached to the tool unit 14. Similarly, the tool unit 14 and the tool pneumatic module 36 are shown adjacent to the tool rack 48 but are not operably disposed in the tool rack 48. The seventh embodiment is described in this configuration, so that all the couplings are shown and the description is facilitated. Fig. 12A to 12F then describe in detail the operation of the robotic tool changer 10, the robot being operated by typical real world operations of attaching, using, parking and detaching a robotic tool. The piston 56 in the main unit 12 may be operably connected to any number of coupling mechanisms to selectively couple the main unit 12 to the tool unit 14. Ball-shifting piston coupling mechanisms are described, for example, in U.S. patent nos. 7,252,453 and 8,005,570. However, any other coupling mechanism may be employed in the tool unit 14-the safety features of the seventh embodiment are applicable to any coupling mechanism that is actuated using fluid pressure (e.g., pneumatic, hydraulic, etc.).

Fig. 11 shows a single air control system 58, preferably mounted on a robotic arm, that provides pneumatic fluid to lock the master unit 12 to the tool unit 14 or unlock from the tool unit 14 in response to optional sensors 82, 84. Pressure sensor 82 or position sensor 84 and their output lines to air control system 58 are shown in phantom to indicate that these elements may not be present in all embodiments. The air control system 58 operates under the control of (i.e., it receives input from and may provide output to) a robot control system (not shown) that coordinates the supply of pneumatic fluid with the physical operation of the robot.

Generally, the air control system 58 may include such valves, controllers, etc., and may perform such functions as needed or desired for a given application. In particular, it is assumed that the air control system 58 comprises a 2-position pneumatic valve that will output pressurized air (and bleed air entering through the other output) on either the "lock air" output or the "unlock air" output, but cannot output on both simultaneously, and always outputs pneumatic fluid on one output or the other. This function is schematically illustrated in fig. 12A to 12F. As will be readily understood by those skilled in the art, the functions of the air control system 58 may also be implemented by two or more separate controllers, wherein mutual exclusivity of the operation of the two pneumatic outputs may be implemented by control logic, interlock signals, and the like.

The pneumatic fluid for driving the piston 56 to couple the main unit 12 and the tool unit 14 together is provided by a lock air output of the air control system 58, which is coupled to a lock air input port 86. The passage 88 connects the lock air input port 86 directly to the coupling port of the piston 56. The air control system 58 outputs pneumatic fluid on the lock air output when the robotic arm having the master unit assembly (including master unit 12 and master pneumatic module 26) is positioned adjacent to the desired tool unit assembly (including tool unit 14 and tool pneumatic module 36) connected to the robotic tool (not shown) disposed in the tool rack 48. This causes the piston 56 in the active unit 12 to actuate, thereby coupling the active unit 12 to the tool unit 14. Furthermore, throughout normal robotic tool operation, i.e., when the robot is performing a task with an attached tool, a positive pressure is maintained at the lock air output of air control system 58. This is a safety feature because positive pressure applied to the coupling chamber of the piston 56 continuously drives the piston 56 to maintain the coupled state.

When the robot control system determines that the attached tool is to be decoupled (e.g., a different tool is attached), it directs the robot to place the tool in a predetermined position in the tool rack 48. According to this seventh embodiment, this also entails positioning at least the tool pneumatic module 36 in a predetermined position on the tool rack 48. The air control system 58 then outputs pneumatic fluid to an unlock air output, which, as described herein, is directed indirectly to the decoupling port of the piston 56, thereby driving the piston 56 to decouple from the tool unit 14. The air control system 58 simultaneously vents air in the lock air line to atmosphere.

According to this seventh embodiment of the invention, the route of the unlocking pneumatic fluid from the unlocking air output of the air control system 58 to the decoupling port of the piston 56 includes a number of safety features, ensuring that the decoupling operation is only possible if the attachment tool (and thus, as schematically shown in fig. 11, the tool pneumatic module 36) is safely disposed in the tool holder 48. Furthermore, as further explained herein, the tool unit assembly and the attached tool are prevented from being unintentionally decoupled due to false air pressure, such as "blow-off" cleaning operations.

The pneumatic fluid from the unlock air output of the air control system 58 is coupled to the unlock air input port 118 and, thus, to the valve 120. The valve 120 is spring biased to a closed position, shutting off the flow of pneumatic fluid whenever the main unit 12 is decoupled from the tool unit 14 and physically moved away from the tool unit 14. As described above, the air control system 58 continuously outputs pneumatic fluid on one output or the other. Since switching to the locked air output will cause the piston 58 to move to the coupled position, preventing the piston 58 from being coupled to another tool unit 14, the air control system 58 continues to provide pneumatic fluid at the unlocked air output when the main unit 12 and the tool unit 14 are decoupled. During this time, the valve 120 prevents the discharge of the pneumatic fluid. When the main unit 12 abuts a new tool unit 14, the plunger extending from the main pneumatic module 26 is depressed by contact with the tool pneumatic module 36, opening the valve 120 and allowing the unlocking pneumatic fluid to flow freely in either direction.

When the main unit 12 and the tool unit 14 are coupled together, the unlocking pneumatic fluid passes through the valve 120 and through the pneumatic coupling 30 between the main pneumatic module 26 and the tool pneumatic module 36. When the attached tool is properly positioned in the tool rack 48 (and thus the tool pneumatic module 36 is also properly positioned on the tool rack 48), the unlocking pneumatic fluid further passes through the channel 62 in the tool pneumatic module 62 and through another pneumatic coupling 68 between the tool pneumatic module 36 and the tool rack 48. A "loopback" passage 70 in the tool rack 48 directs the unlocking pneumatic fluid back into the tool pneumatic module 36.

The unlocking pneumatic fluid returned from the tool rack 48 into the tool pneumatic module 36 passes through the safety coupling 122. The safety coupling 122 includes a male coupling member 122a on the tool rack 48 that is received in a female coupling member 122b when the tool pneumatic module 36 is properly oriented on the tool rack 48. The male coupling member 122a is generally cylindrical with a sealing O-ring at the base end and a tapered adapter at the distal end. An air passage hole is formed in the cylindrical portion. The female coupling member 122b comprises two coaxial cylindrical bores. The lower bore opens to the exterior of the tool holder 48 and is sized and shaped to receive the cylindrical portion of the male coupling member 122 a. The upper bore is smaller in diameter than the lower bore and is open to the atmosphere. A sealing O-ring is disposed at the intersection of the upper and lower bores.

In operation, when the tool pneumatic module 36 is properly seated on the tool rack 48 and aligned with the tool rack 48, the cylindrical portion of the male coupling member 122a is disposed within the lower bore of the female coupling member 122 b. The lower bore is sealed at the lower end by contact with an O-ring at the base of the male coupling member 122 a. The lower bore is also sealed at the upper end by a tapered nipple of male coupling member 122a that presses against an O-ring at the intersection of the lower and upper bores of female coupling member 122 b. The pneumatic fluid escapes through an air passage hole formed in the cylindrical portion of the male coupling member 122a and is directed through the passage 76 that communicates with the lower hole of the female coupling member 122 b.

The safety coupling 122 ensures that the tool pneumatic module 36 must be properly seated and aligned on the tool rack 48. If the lower or upper O-ring fails to seal, pneumatic pressure will be lost to the atmosphere and will not drive the piston 56 to decouple. In one embodiment, proper alignment between the tool pneumatic module 36 and the tool rack 48 is aided by one or more alignment pins 124 on the tool unit 14 or the tool pneumatic module 36 and corresponding alignment holes 126 in the tool rack 48. Of course, similar locator/alignment features may be provided on the attached robotic tool. Although described herein as O-rings, any suitable sealing element may be utilized to provide a pneumatic seal at the lower and upper ends of the lower bore of female coupling member 122 b.

The unlocking pneumatic fluid from the safety coupling 122 passes through the channel 76, the pneumatic coupling 40 between the tool pneumatic module 36 and the main pneumatic module 26, and through the channel 60 to the decoupling port of the piston 56. In the illustrated embodiment, a sealing O-ring is provided at the interface of the air passage 60 between the main air module 26 and the main unit 12.

The operation of the seventh embodiment of the present invention is described with reference to fig. 12A to 12F, in which identification numerals of the internal passage, the coupling, and the like are omitted for clarity. Fig. 12A-12F also depict a 2-position pneumatic valve in the air control device 58, which operates under the control of a robotic control system (not shown). In fig. 12A, the main unit 12 is attached to a robot arm (not shown), and no tool is attached. The piston 56 is in the unlocked or decoupled position and no pressure is applied to the coupled or decoupled ports. The unlock sensor 82 (if present) outputs a signal indicating that the piston 56 is in the unlocked position. The valve in the air control system 58 outputs pneumatic fluid on the unlock air output, which is blocked by the spring loaded valve 120.

Fig. 12B shows the seventh embodiment when the robotic arm moves the main unit 12 into initial contact with the tool unit 14. The valves in the air control system 58 switch to output pneumatic fluid on the lock air output and exhaust pneumatic fluid in the lock release air line. The lockout pneumatic fluid begins to drive the piston 56 toward the coupled or locked position, as indicated by the pressure arrows in the coupling chamber of the piston 56. This attempts to drive the pneumatic fluid out of the decoupling port, which (to the extent that it does not leak out of the incompletely sealed couplings 30, 40) forces pressure through the tool pneumatic module 36, the tool holder 48, the tool pneumatic module 36 and the main pneumatic module 26, where the pressure stops through the valve 120, which valve 120 remains closed when its plunger is not fully depressed.

Fig. 12C shows the seventh embodiment after the main unit 12 has been fully mated with the tool unit 14 and coupled to the tool unit 14. The valve 120 is depressed open by its plunger contacting the tool pneumatic module 36 and the unlocking pneumatic fluid from the decoupling chamber of the piston 56 is vented through a valve in the air control system 58. Note that in order for the unlocking pneumatic fluid to pass through the tool pneumatic module 36 and the tool rack 48, the tool pneumatic module 36 must be seated on and properly aligned with the tool rack 48. This is required so that the lower bore of the female portion 122b of the safety coupling 122 is sealed at both its upper and lower ends, thereby containing the unlocking pneumatic fluid within the path through the tool pneumatic module 36 and the tool rack 48, as shown. The valve of the air control system 58 continuously supplies the lock-up pneumatic fluid to the coupling chamber of the piston as indicated by the pressure arrows. The lock sensor 84 (if present) indicates that the piston 58 is in the locked or fully coupled position.

In fig. 12D, the robot has removed the main unit assembly and the coupled tool unit assembly (with the robot tool attached, not shown) from the tool rack 48. The air control system 58 continues to provide positive pneumatic pressure on the lock air line, continuously driving the piston 56 to the coupled position. The lock sensor 84 (if present) continues to indicate that the piston 58 is in the locked or fully coupled position.

The seventh embodiment of the present invention, in one embodiment thereof, includes an additional safety feature that prevents the unlikely but possible cause of accidental decoupling of the tool unit 14 from the main unit 12. Before discussing this feature, it should be noted that fig. 11 and 12A-12F are pneumatic schematic diagrams-they are not, for example, cross-sectional views. Although not apparent in fig. 12A-12F, and as best seen in fig. 13 and 14, at least a portion of the tool pneumatic module 36 extends outwardly (out of the plane of the drawing) from the main pneumatic module 26 when the main unit 12 and the tool unit 14 are coupled together.

One key to the operation of safety coupling 122 is that the upper bore of female portion 122b is open to atmosphere, which requires the upper tapered portion of male portion 122a to press against an O-ring to form a seal so that the lower bore becomes a sealed chamber that supports the transfer of pneumatic fluid (as opposed to venting pneumatic fluid to atmosphere). Although in fig. 12D it will occur that the upper bore is sealed (or at least blocked) by contact with the main pneumatic module 26, this will not actually occur. As shown in fig. 13 and 14, the concave portions 122b of the safety couplings are formed on the portion of the tool pneumatic module 36 that extends outward from the main pneumatic module 26, and therefore do not contact therewith.

Similarly, at least one through-hole 123 located near the concave portion 122b of the safety coupling 122 extends through a portion of the tool pneumatic module 36 that extends outwardly from the main pneumatic module 26. As shown in fig. 13 and 14, two or more through holes 123 may be provided. Fig. 13 is a perspective view of the robotic tool changer 10, and fig. 14 is a cross-sectional view taken through the center of the female portion 122b of the safety coupling 122 on the tool pneumatic module 36.

The through-hole 123 preferably has a larger diameter along the entire length thereof than the upper chamber of the concave portion 122 b. When the tool is attached and in operation (i.e. not in the tool holder 48), each through-hole 123 provides a low resistance path for compressed air which is directed towards the lower bore of the female portion 122b of the safety coupling 122. Many robotic operations, such as grinding, sanding, milling, deburring, etc., generate debris, such as drill cuttings, dust, or other particles, the accumulation of which can interfere with the task being performed. Thus, in some robotic operations, it is common practice to periodically pause the task at hand and clean the robotic tools and robotic tool changer surfaces by blowing compressed air over them. If a technician directs a flow of compressed air over the opening to the upper or lower bore of the female portion 122b of the safety coupling while his hand or other object blocks the opposite opening, air pressure can be directed through the channels 76 and 60 (see fig. 11) to apply pressure to the decoupling port of the piston 56. If this pressure exceeds the pressure provided by the air control system 58 outputting the locking pneumatic fluid on the locking air output, the piston 56 may move toward the decoupled or unlocked position, allowing the tool unit 14 (and thus the attached tool) to be decoupled from the main unit 12, resulting in an unsafe "tool drop" event.

Providing one or more through-holes 123 located near concave portion 122b of safety coupling 122 reduces this potential for mistaking. The through-holes 123 provide a low resistance path for extraneous compressed air flow and divert the air flow that might otherwise pass through the pneumatic channels 76, 60. In fact, testing has shown that in many cases, the high flow of compressed air through the through-hole 123 creates a venturi effect and actually reduces the air pressure in the lower bore of the female portion 122b of the safety coupling 122 to slightly below atmospheric pressure. Although only one through-hole 123 is shown in fig. 11 and 12A to 12F, preferably, as shown in fig. 13 and 14, two or more through-holes 123 are provided to reduce the possibility that all through-holes are simultaneously blocked during the compressed air blow-off cleaning operation. Fig. 14 is a cross-sectional view taken through female portion 122b of safety coupling 122, showing lower and upper bores, sealing O-rings, and pneumatic channel 76. The via 123 is indicated by a dotted line.

Fig. 12E shows the seventh embodiment after the robot has returned the tool to the tool rack 48 and the main unit 12 has been decoupled from the tool unit 14. A valve in air control system 58 outputs pneumatic pressure on the unlock air output and exhausts the pneumatic fluid returning in the lock air line. For example, the air control system 58 may receive a signal from a tool rack sensor (not shown) indicating that a tool is disposed in the tool rack. The unlocking pneumatic fluid flows through the valve 120 in the main pneumatic module 26 (which is held open by its plunger being depressed by contact with the tool pneumatic module 36), and through the tool pneumatic module 36 and the tool rack 48. Because the pneumatic module 36 is seated on the tool rack 48 and properly aligned with the tool rack 48, the lower bore of the female portion 122b of the safety coupling is sealed at both the lower and upper ends, and pneumatic fluid flows from the tool rack, through the safety coupling, and to the decoupling port of the piston 56, as indicated by the pressure arrows in the decoupling chamber. An unlock sensor (if present) indicates that the piston 56 is in the unlocked or decoupled position.

Fig. 12F shows the seventh embodiment after the main unit 12 and the tool unit 14 have been decoupled and the robot has removed the main unit assembly from the tool unit assembly (e.g., to attach a different tool). To prevent the piston 56 from moving to the coupled position, which may interfere with attachment to a different tool unit 14, the air supply system 58 continues to output pneumatic fluid on the unlock air output (avoiding pressurizing the lock air line). However, the valve 120 in the main pneumatic module 26 stops the flow of pneumatic fluid because the plunger is no longer depressed by contact with the tool pneumatic module 36. The unlock sensor (if present) indicates that the piston 56 is in the unlocked or decoupled position and is ready for attachment to a different robotic tool.

Fig. 15 shows an intrinsically safe method 130 of removing a robot tool from a robot according to a seventh embodiment. The main unit assemblies 12, 26 of the tool changer 10 are attached to the robot and the tool unit assemblies 14, 36 of the tool changer 10 are attached to the robot tool. A pneumatic coupling mechanism 56 selectively couples the main unit assembly 12, 26 and the tool unit assembly 14, 36 to one another. The robot is positioned to place the tool in a predetermined position in the tool rack 48 (block 132). Pneumatic fluid is received from the air source 58 (block 134). The pneumatic fluid is directed to the tool holder (block 136). For example, as shown in fig. 11, pneumatic fluid is received at the unlock air input port 118, passes through the valve 120 (because the main pneumatic module 26 and the tool pneumatic module 36 abut), and then passes through the coupling 30, the channel 62, and the coupling 68 to the tool rack 48. If the tool unit assemblies 14, 36 are seated on the tool rack and properly aligned (block 138), pneumatic fluid is received from the tool rack 48 via the safety coupling 122. The pneumatic fluid is then directed to a decoupling port of the pneumatic coupling mechanism 56 (block 140), for example, via the channel 76, the coupling 40, and the channel 60. On the other hand, if the tool unit assemblies 14, 36 are not seated on the tool rack, or are not properly aligned (block 138), the pneumatic fluid from the tool rack 48 is vented to atmosphere (block 142) because the lower bore of the coupling member 122b of the safety coupling 122 will not seal properly. In this case, the pressure is lost and the pneumatic coupling mechanism 56 cannot move to the decoupled position.

This seventh embodiment of the invention provides a critical safety feature that ensures that the robotic tool is safely disposed in the tool rack 48 before the tool device 14 can be decoupled from the master device 12. Because the actual motive force driving the piston 56 to the decoupled position is transmitted through the tool rack, it is not possible for the main unit 12 to decouple the tool unit 14 whenever the tool pneumatic module 36 is not properly positioned on the tool rack, even if a software malfunction or other improper operation allows such a command to be issued. In addition, the tool and tool pneumatic module 36 must be in place and aligned on the tool rack to achieve decoupling through the safety coupling 122. The through-holes 123 may even reduce the likelihood of accidental tool drops when the tool changer 10 is blown clean with compressed air.

The seventh embodiment is very cost effective-only a single air control system 58 on the robot arm is required (no separate air supply or control valve is required on each tool rack). In addition, the tool rack loopback feature and tool pneumatic module 36 includes only fittings, couplings, and air passages, and does not require valves, controllers, electronics, etc. Only a single valve is required in the primary pneumatic unit 26 to prevent the flow of any pneumatic fluid output by the unlock air output of the air control system 58 when the primary unit 12 and the tool unit 14 are decoupled and decoupled.

As used herein, the term "pneumatic fluid" refers to a pressurized gas, such as compressed air, operable to transfer energy in a pneumatic system. In particular, a pneumatic fluid is a gas at a pressure above ambient atmospheric pressure. In general, it is assumed that the pneumatic fluid is suitably conditioned, e.g., suitably filtered, in terms of gas composition, humidity, pressure, etc., to be substantially free of particles or contaminants.

Although described as being disposed in the main and tool unit pneumatic modules 26, 36 that are attached to the main and tool units 12, 14, respectively, in other embodiments pneumatic valves, pneumatic conduits, pneumatic channels, safety couplings, control signals, etc. may be disposed in the main and tool units 12, 14 themselves. Thus, as used herein, for each embodiment, the term "main unit assembly" refers to an assembly of the main unit 12 and the main unit pneumatic module 26, or an assembly of the main unit 12 that individually includes the pneumatic components operated by the main unit pneumatic module 26. Similarly, for each embodiment, the term "tool unit assembly" refers to the assembly of the tool unit 14 and the tool unit pneumatic module 36, or the tool unit 12 alone including the operative pneumatic components of the tool unit pneumatic module 36.

The present invention may, of course, be carried out in other ways than those specifically set forth herein without departing from essential characteristics of the invention. The present embodiments are to be considered in all respects as illustrative and not restrictive, and all changes coming within the meaning and equivalency range of the appended claims are intended to be embraced therein.

Claims (10)

1. A robotic tool changer (10), characterized by:

a main unit assembly comprising a main unit (12) and a main powered module (26) operatively connected to the robot;

a tool unit assembly comprising a tool unit (14) and a tool pneumatic module (36) operatively connected to the robotic tool and also operatively aligned with and seated on the tool holder (48) when the connected robotic tool is disposed in the tool holder (48);

a pneumatically actuated coupling mechanism (56) disposed in one of the main unit assembly and the tool unit assembly operable to selectively couple the main unit assembly and the tool unit assembly together;

wherein pneumatic fluid operable to decouple the main unit assembly and the tool unit assembly from the tool holder (48) via the coupling (122) is received from the tool holder (48) only when the tool unit assembly is seated on the tool holder (48) and aligned with the tool holder (48), whereby the coupling mechanism (56) can be decoupled only when an attached robotic tool is disposed in the tool holder (48).

2. The tool changer (10) of claim 1, wherein pneumatic fluid operatively coupling the coupling mechanism (56) to couple the main unit assembly and the tool unit assembly together is received from an air control system (58).

3. The tool changer (10) of claim 1 or 2, wherein the pneumatic fluid received from the tool rack (48) via a safety coupling (122) operable to decouple the main unit assembly and the tool unit assembly by the coupling mechanism (56) is received by the tool changer (10) from an air control system (58) and directed to the tool rack (48).

4. The tool changer (10) of any one of claims 1-3, wherein the safety coupling (122) comprises a female coupling member (122b) formed in the tool changer (10), the female coupling member (122b) comprising:

a lower bore open to the exterior and facing the tool holder (48), the lower bore being sized and shaped to receive a corresponding male coupling member (122a) provided on the tool holder (48);

an upper hole in airflow communication with the lower hole, the upper hole being open to the outside;

a first sealing member disposed proximate an intersection between the lower bore and the upper bore; and

a pneumatic fluid passage (76) connecting the lower bore in gas flow communication, the pneumatic fluid passage leading to a decoupling port of the coupling mechanism (56).

5. The tool changer (10) of claim 4, wherein the upper bore and the lower bore are coaxial.

6. The tool changer (10) of claim 4 or 5, wherein when a tool attached to the tool changer (10) is disposed in the tool rack (48),

a male coupling member (122a) on the tool holder (48) disposed within the lower bore and at least partially disposed within the upper bore;

the first sealing member operatively seats against the male coupling member (122a) sealing the lower bore from the upper bore and thus from the exterior through the upper bore; and

the exterior of the tool changer (10) at the lower aperture is operable to seat against a second sealing member provided on the tool holder (48) to seal the lower aperture from the exterior;

whereby the lower bore is sealed from the exterior and pneumatic fluid directed from the toolhead (48) through an air flow opening in the male coupling member (122a) and into the lower bore flows through the pneumatic fluid passage to a decoupling port of the coupling mechanism (56); and

thus, any misalignment of the tool changer (10) on the tool holder (48) results in one or both seals failing and pneumatic fluid directed from the tool holder (48) through the airflow opening in the male coupling member (122a) and into the lower bore escapes to the outside.

7. The tool changer (10) of any one of the preceding claims, wherein

The coupling mechanism (56) is provided in the main unit assembly;

each of the main unit assembly and the tool unit assembly including first and second pneumatic couplings (30, 40) positioned to mate in a pneumatic fluid flow relationship when the main unit assembly and the tool unit assembly are coupled together and operable to transfer pneumatic fluid between the tool unit assembly and the main unit assembly; and is

The main unit assembly includes a pneumatic fluid conduit (60) operable to direct pneumatic fluid between the tool unit assembly and the decoupling port of the coupling mechanism (56) via one of the first and second pneumatic couplings (30, 40).

8. The tool changer (10) of claim 7,

the tool unit assembly comprising third and fourth pneumatic couplings (68, 122) positioned to mate in pneumatic fluid flow relationship with respective pneumatic couplings (68, 122) on the tool holder (48) when a tool attached to the tool unit assembly is disposed in the tool holder (48); and is

Wherein pneumatic fluid supplied from the tool unit assembly to the tool rack (48) via a third pneumatic coupling (68) is received by the tool unit assembly from the tool rack (48) via a fourth pneumatic coupling (122).

9. An intrinsically safe method (130) of detaching a robotic tool from a robot, wherein a main unit assembly of a tool changer (10) is attached to the robot and a tool unit assembly of the tool changer (10) is attached to the robotic tool, and wherein a pneumatic coupling mechanism (56) selectively couples the main unit assembly and the tool unit assembly to each other, the method characterized by:

positioning (132) the robot to place the tool in a predetermined position in a tool holder (48);

receiving (134) pneumatic fluid from an air source (58);

directing (136) the pneumatic fluid to the tool holder (48);

receiving pneumatic fluid from the tool holder (48) via a safety coupling (122), the safety coupling (122) operable to pass the pneumatic fluid under pressure only when (138) the tool unit assembly is seated on the tool holder (48) and aligned with the tool holder (48), and operable to vent (142) the pneumatic fluid to atmosphere when (138) the tool unit assembly is not seated on the tool holder (48) or aligned with the tool holder (48); and is

Directing (140) pneumatic fluid from the safety coupling (122) to a decoupling port of the pneumatic coupling mechanism (56) when (138) the tool unit assembly is seated on the tool rack (48) and aligned with the tool rack (48), thereby causing the pneumatic coupling mechanism (58) to decouple the main unit assembly from the tool unit assembly.

10. The method (130) of claim 9, further comprising, while decoupling the main unit assembly from the tool unit assembly:

stopping the introduction of pneumatic fluid to the tool holder (48) by closing a pneumatic fluid valve (120) interposed between the air source (58) and the tool holder (48);

and wherein the one or more of the one,

the pneumatic fluid is received by the main unit assembly from the air source (58);

the valve (120) is provided in the main unit assembly;

the valve (120) is opened by abutment with the tool unit assembly; and is

The valve (120) is closed by the action of a spring when the main unit assembly is not in abutment with the tool unit assembly.

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