GB2192855A - Tool-change coupling for robots - Google Patents

Abstract

A coupling device for use in enabling a robotic unit to couple automatically with any one of a number of tools, comprises two coupling parts (22, 26) connected respectively to the tool and the arm. The two parts can be brought into interengaged relationship by appropriate manipulation of the arm and can then be locked together by means of a locking element (44), controlled by piston and cylinder assembly (48), which enters a tapered bore (32) in a spigot (30) after the spigot, which is mounted on the coupling part (22), has entered a bore in the other coupling part. The parts (22, 26) also incorporate registering passages (54, 34) for providing continuity of pressurised air supply between the robotic unit and a fluid-powered device incorporated in the tool. <IMAGE>

Description

SPECIFICATION Coupling device This invention relates to a coupling device for use in the attachment of tools to robotic apparatus.

According to the present invention there is provided a coupling device comprising a first part attachable to or forming part of a robotic unit, a second part attachable to or forming part of a tool for connection to the robotic unit, each coupling part including power supply connection means and being interengageable to provide, in use, continuity of power supply between the robotic unit and the tool, and power-operated locking means for releasably securing the two coupling parts together.

The locking means is preferably provided on the first coupling part so that the locking means, in use, effectively forms part of the robotic unit. In practice, the robotic unit may be used with any one of a plurality of tools in which event each tool type may be provided with a respective second coupling part whereby any one of the tools can be selectively connected to the robotic unit by effecting coupling between the second coupling part associated with the tool and the first coupling part associated with the robotic unit.

The first coupling part is conveniently attached to or forms part of a manipulating arm of the robotic unit so that, in use, the arm can be operated in such a way as to register the first coupling part with the second coupling part of the desired tool, the locking means being operated to secure the two coupling parts together after they have been properly registered. When properly registered and secured together by the locking means, the coupling parts provide continuity of power supply so that the tool can be connected to a power source. Thus, for example, the tools may be fluid-pressure operated in -which case the power source may be hydraulic or pneumatic and the power supply connection means incorporated in the first and second coupling parts may comprise fluid supply passages which register when the coupling parts are locked together.

The locking element of the locking means is advantageously biassed, for example by spring loading, to its locking position so that the coupling parts remain locked together in the event of a power failure.

To promote further understanding of the invention, an embodiment will now be described by way of example only with reference to the accompanying drawings, in which: Figure 1 is an exploded schematic side view of a robotic unit showing the tool separated from the robot arm; and Figure 2- is an axial sectional view through the coupling device.

Referring to Figure 1, the robotic unit comprises an arm 10 having a number of articulated and swivel connections, eg 12, 13, 14, 15 and mounted on a column 16 about the axis of which the arm 10 may be swivelied to allow a wide variety of manipulation tasks to be executed. The robotic unit msy be powered pneumatically for example and may be operable remotely by way of an operating console so that the unit may be used in hazardous or toxic environments without risk to the operator. For instance, the unit may be located within a hot cell of a nuclear fuel fabricating or reprocessing facility and may be operated from a console external to the hot cell.

In practice, a variety of tools may be required to be connected, one at a time, to the robotic arm. Hitherto, this has been done manually by releasing fasteners securing one tool to the arm and retightening the fasteners to secure the replacement tool to the arm.

In Figure 1, only one tool (a pneumaticallyoperable gripper) 20 is illustrated but it will be understood that in practice a number of different tool types will be available. Each tool 20 has a coupling part 22 secured to its inboard end and, when not in use, the tool can be stored on a rack 24. To this end, the rack may include a number of generally U-shaped cut-outs for reception of the coupling parts 22, the coupling parts being formed locally with a contour which is a complementary nonrotatable fit with each of the U-shaped cutouts so that the tool is supported by the rack in cantilever fashion and in a predetermined angular orientation.

The arm 10 terminates in a coupling part 26 by means of which each tool can be coupled to the arm through the agency of the coupling part 22. In Figure 1, the parts 22, 26 are shown separated. By appropriate manipulation and extension of the arm, the parts 22, 26 can be interengaged as shown in Figure 2.

The coupling part 22 comprises an annular body 28 to which a stem 30 is secured so as to be captive both axially and rotatably with the body. The stem 30 forms a spigot which is formed with a transverse tapering bore 32 adjacent its end. The body 28 is formed with a number of passages 34 (one only shown in Figure 2) which, at one end, open at the face 36 and at their other ends terminate in threaded outlets 38 for reception of pneumatic pipe fittings. The body 28 is adapted (by means not shown) to be fastened to the respective tool 20.

The coupling part 26 comprises an annular body 40 forming a socket for close fitting reception of the spigot 30. The face 42 of the body 40 is of complementary shape to the face 36 of coupling part so that the two parts can be brought together in face-to-face engagement. The coupling parts may be provided one with a dowel (not shown) and the other with a bore for reception of the dowel to ensure that the two parts 22, 26 can only be brought together into correct operative relationship by angular alignment of the dowel and bore thereby ensuring that the two parts 22, 26 are in a predetermined angular relationship on being coupled together.

When so coupled, the bore 32 will be in transverse alignment with a plunger 44 whose end portion is formed with a taper complementary to that of the bore 32. The plunger 44 is coupled to the piston 46 of a single acting piston and cylinder assembly 48 which, when supplied with fluid under pressure, is operable to withdraw the plunger 44 clear of the bore 32. A spring 50 urges the plunger 44 in the opposite direction, ie for engagement in the bore 32. The plunger 44 has a wedge-like action on entering the bore 32 and serves to draw the surfaces 36 and 42 closely together thereby providing a sealing action by compression of O-ring seals 52. The seals 52 are provided around those ends of passages 54 which open at the surface 42.

The passages 34 and 54 are arranged to align with each other when the coupling parts 22, 26 are brought together in the correct operative relationship (ie so that the dowel and bore register) thereby providing continuity between threaded inlets 56 ana outlets 38.

The body 40 is secured, eg by threaded fasteners (not shown), to the end of the arm 10. The pneumatic supply to the piston and cylinder assembly 38 is provided via piping 60 (see Figure 1) via a controi valve (eg a solenoid-controlled valve) which may be housed within the robotic unit and may be operable from the operator console. The supply of pressurised air to the tool is affected via piping 62, 64 connected between remotely operabie valves (eg solenoid-controlled valves) housed in the robotic unit and the inlets 56 of the coupling part 26, via passages 54 and 34 and finally via piping 66, 68 interconnecting the outlets 38 and a fluid powered device incorporated in the tool.

In use, when a particular tool is to be connected to the arm 10, the latter is manipulated to address the-required rack-mounted tool in such a way that the coupling parts 22, 26 are correctly aligned. The arm is then operated to advance the socket part 26 until it is fully engaged with the spigot part 22.At this time, the plunger 44 will be held retracted by the application of pressure to the piston and cylinder assembly 48 so that entry of the spigot 30 into the socket is unimpeded by the plunger 44. -After the two parts have been properly interengaged, the pressure supply to the piston and cylinder assembly 48 is removed allowing the spring 50 to drive the plunger 44 into the bore 32-so as to lock the two parts together with the passages 34 and 54 sealed together in -registry. The rack serves to restrain the tool against axial displacement during the coupling action. Once coupling has been effected, the arm is manipulated to raise the tool out of the U-shaped cut-out in the rack 24. Operation of the tool can now be effected by control of the air supply via piping 62, 64 and 66, 68.

To decouple the tool from the arm, the latter is manipulated to locate the tool on the rack 24, the piston and cylinder assembly is operated to retract the plunger 44 and the arm is withdrawn away from the rack 24 to separate the coupling parts 22, 26.

It will be seen that the coupling device is fail-safe in that the locking action exerted by the spring 50 is maintained and does not rely upon the pneumatic supply. If desired, the piston and cylinder assembly may be of the double-acting type but, in this event, a spring is still preferably provided to ensure a fail-safe locking action. In general, to minimise loading of the arm, the various components of the coupling device will be fabricated from lightweight materials such as plastics, aluminium or aluminium alloy.

Claims (18)

1. A coupling device comprising a first part attachable to or forming part of a robotic unit, a second part attachable to or forming part of a tool for connection to the robotic unit, each coupling part including power supply connection means and being interengageable to provide, in use, continuity of power supply between the robotic unit and the tool, and power-operated locking means for releasably securing the two coupling parts together.

2. A coupling device as claimed in Claim 1 in which the locking means is provided on the first coupling part.

3. A coupling device as claimed in Claim 1 or 2 in which the locking element of the locking means is biassed towards its locking position.

4. A coupling device as claimed in any one of Claims 1 to 3 including means for allowing operative interengagement of the first and second parts only when they are in predetermined reiationship with each other.

5. A coupling device as claimed in any one of Claims 1 to 4 in which the power supply connection means comprise fluid-conducting passages.

6. A coupling device as claimed in any one of Claims 1 to 5 in which the locking element is operable to effect locking with a wedging action so as to draw the two coupling parts together in face-to-face engagement.

7. A coupling device as claimed in Claim 6 in which the locking element is mounted by one coupling part and has a tapering leading end which, to effect locking engagement, is engageable in a generally complementary tapering bore in the other coupling part.

8. A coupling device as claimed in any one of Claims 1 to 7 in which the locking means comprises a fluid pressure operable piston and cylinder assembly and a locking element mov able with the piston.

9. A coupling device as claimed in Claim 8 in which the piston and cylinder assembly is single acting, spring means being provided for biassing the locking element towards its locking position, the pressure operated stroke of the piston being arranged to withdraw the locking element from its locking position to allow separation of the coupling parts.

10. A coupling device as claimed in Claim 8 in which the piston and cylinder assembly is double acting, spring means being provided to bias the locking element towards its locking position.

11. A coupling device as claimed in any one of Claims 1 to 10 in which the coupling parts are fabricated from a lightweight material (such as aluminium, aluminium alloy or plastics material).

12. A coupling device as claimed in any one of Claims 1 to 11 in which the coupling parts are configured so as to make spigot and socket engagement, the locking means being provided on the coupling part embodying the socket. and being arranged so that its locking element is movable transversely of the spigot and is engageable with a bore or opening in the spigot to effect locking of the coupling parts together.

13. A coupling device substantially as hereinbefore described with reference to, and as shown in, the accompanying drawings.

14. In combination, a robotic unit provided with a first coupling part and at least one power-operable tool provided with a second coupling part, the first part and the or each second- part comprising a coupling device as claimed in any one of Claims 1 to 13.

15. The combination according to Claim 14 in which the robotic unit is adapted for connection to a source of pressurised fluid and includes valve means for controlling the supply of -pressure fluid to the locking means and to a tool coupled to the robotic unit, the pressure fluid supply to the tool being effected through the agency bf the power supply connection means of the coupling device.

16. The combination of Claim 14 or 15 further including tool storage rack means for supporting the or each tool while decoupled from the robotic unit.

17. The combination as claimed in Claim 16 in which the rack means is designed to support the or each tool by means of its second coupling part.

18. The combination as claimed in Claim 17 in which the rack means comprises, for the or each tool, a receiving section having a generally U-shaped configuration, the or each second coupling part having a complementary Ushaped contour for seating non-rotatably within the receiving section.