GB2528892A

GB2528892A - Actuator unit for a bending machine

Info

Publication number: GB2528892A
Application number: GB1413714.5A
Authority: GB
Inventors: Alan Bradley George Pickering; Terence John Pickering; Michael Ian Lawson; James Michael Dobson
Original assignee: UNISON Ltd
Current assignee: UNISON Ltd
Priority date: 2014-08-01
Filing date: 2014-08-01
Publication date: 2016-02-10
Also published as: GB201413714D0

Abstract

An actuator unit 30 for a bending machine (10, figure 1) for pipes (20) comprises two guide screw rods 50 and two servo motors 48. Each motor is coupled to a respective screw 50 to rotate it. Each screw may have an associated nut 52 driven along it. The motors may be aligned with and located above or beneath respective screws. The servo motors may be parallel with and to one side of the screws and the motors may be aligned parallel with one another. Such arrangements provide for a compact bending machine with a relatively small footprint. Each motor is configured to deliver equal torque to their screws. A belt or chain may connect motors to respective screws. A bending machine may comprise a clamp die (13), a movable pressure die (12), and a mandrel (14), each actuated by a respective actuator. The servo motors may be controlled to have the same output and one of the motors may be controlled in dependence on feedback of the output of the other. The output may be torque, angular rotation, position or force. The bending machine may comprise a bending arm (32, figure 7) actuated by three or more servo motors (98) which deliver equal torque.

Description

ACTUATOR UNIT FOR A BENDING MACHINE

The present disclosure relates to an actuator unit.

In particular it relates to an actuator unit for bending machine and method of operating an actuator unit for bending machine.

Background

Many different designs of bending machines exist and are known in the art.

At the higher end of customer requirements, pipes have a large diameter, thick walls and are made of specialist materials, and consequently are difficult to bend. In addition to support platforms needed to seat the pipe, which will tend to be several metres in length, the positioning, clamping and bending arrangements of such a machine must be sufficient to achieve the desired pipe deformation. Pipes are clamped and bent using a variety of actuators, including hydraulic, pneumatic and electrically powered actuators which have become larger to cope with increasing force and torque demands.

Additionally the requirement for a mandrel to be located in the pipe at the region of bending, and the withdrawal of such after the bend is complete, requires a tailstock with actuators which also have increased with size as the required power output from such devices has increased. Hence the overall volumetric size and area "footprint" of industrial bending machines has increased. Generally, however, manufacturing plants have become more expensive per unit area, and certainly more crowded, and hence there is a requirement to keep the size of industrial bending machines to a minimum.

Also, customers needs have increased to such an extent that in order to achieve the desired functionality, large (i.e. industrial) electrically actuated bending machines now require specially designed and manufactured motors, shafts and drive rods to be made, the specifications of "off the she/f' components no longer being sufficient. This increases the final cost to the end customer as manufacturing and maintenance costs are thus also increased.

Hence a bending machine which has a high rating but which occupies a minimal area footprint and whose manufacturing and maintenance costs are also minimal, is highly desirable.

Summary

According to the present disclosure there is provided apparatus and method as set forth in the appended claims. Other features of the invention will be apparent from the dependent claims, and the description which follows.

Accordingly there may be provided an actuator unit (30, 70, 110) for a bending machine (10) for bending pipes (20), wherein the actuator unit (30) comprises: two guide screw rods (50, 76, 116); two servo motors (48, 78, 118); one of the servo motors being coupled to one of the guide screw rods (50, 76, 116), the other servo motor being coupled to the other guide screw rod (50, 76, 116), each servo motor (48, 78, 118) operable to rotate the screw rod (50, 76, 116) to which it is coupled.

Each servo motor (48, 78, 118) may be provided substantially parallel and substantially to one side of the screw rod (50, 76, 116) to which it is coupled.

The servo motors (48, 78, 118) may be arranged aligned parallel with one another.

Each of the servo motors (48, 78, 118) may be configured to deliver substantially equal torque to their respective screw rods (50, 76, 116).

A screw nut (52, 74, 114) may be rotatably engaged with each of the screw rods (50, 76, 116); and each of the screw nuts (52, 74, 114) may be operable to be driven along their respective screw rod (46) by rotation of the screw rod.

The servo motors (48, 78, 118) may be substantially aligned with the screw rods (50, 76,116).

The servo motors (48, 78, 118) may be provided beneath or above the screw rods (50, 76, 116).

The servo motors (48, 78, 118) may be substantially vertically aligned with the screw rods (50, 76, 116).

The servo motors (48, 78, 118) may be substantially horizontally aligned with the screw rods (50, 76, 116).

Each screw rod (50, 76, 116) may be coupled to, and driveable by, one of the servo motors (48, 78, 118) via a belt or chain (54).

There may also be provided a bending machine (10) for bending pipes (20), the bending machine comprising: a bending former (11) having a forming surface (40) which is centred on a central axis (42); a clamp die (13) for clamping a pipe (20) to the bending former (11); and an actuator unit (30) according to the present disclosure for driving the clamp die (13) to/from the bending former (11).

The bending machine may further comprise a clamp die connection rod (46) which acts on the clamp die (13); the clamp die connection rod (46) being coupled to the screw rods (50) via the screw nuts (52); the clamp die connection rod (46) being configured as a conduit for communicating force generated by rotation of the screw rods (50) to the clamp die (13).

There may also be provided a bending arm (32) which comprises the clamp die (13) and clamp die actuator unit (30), and the bending arm (32) is rotatably mounted and operable to rotate with the clamp die (13) and the clamp die actuator unit (30) about the central axis (48) of the bending former (11) to thereby displace the clamp die (13) around the forming surface (40) of the bending former (11), the clamp die actuator unit (30) being operable to force the clamp die (13) against the bending former (11) while it is being rotated about the central axis (42) of the bending former (11) with the clamp die (13).

The bending arm (32) may be coupled to a drive mechanism (90) operable to rotate the bending arm (32) about the bending former central axis (42) the bending arm drive mechanism comprising: a shaft (94) aligned with the bending former central axis (42), wherein the shaft extends perpendicular to the direction in which the clamp die actuator unit (30) and clamp die (13) are aligned; and a plurality of bending arm servo motors (98) operable to rotate the shaft (94) to thereby drive the bending arm (32) about the bending former central axis (42).

Each of the bending arm servo motors (98) may be configured to deliver substantially equal torque to the bending arm shaft (94).

There may also be provided a bending machine (10) for bending pipes (20), the bending machine comprising a moveable pressure die (12) operable to move to a position to engage with a pipe (20); an actuator unit (70) according to the present dislcosure for driving the pressure die (12) to the pipe engagement position.

The pressure die actuator unit (70) may comprise a pressure die connection rod (72) which acts on the pressure die (12), the pressure die connection rod (72) being coupled to the screw rods (76) via the screw nuts (74) of the pressure die actuator unit (70); the pressure die connection rod (72) being configured as a conduit for communicating force generated by rotation of the pressure die screw rods (76) to the pressure die (12).

There may also be provided a bending machine (10) for bending pipes (20), the bending machine comprising a moveable pressure die (12) operable to move to a position to engage with a pipe (20); an actuator unit (70) according to the present disclosure for driving the pressure die (12) to the pipe engagement position wherein each screw rod (76) of the pressure die actuator unit is coupled to its respective servo motor (78) via a pressure die gear unit (80); each pressure die servo motor (78) being provided substantially at right angles to the pressure die screw rods (76).

There may also be provided a bending machine (10) for bending pipes (20), the bending machine comprising a mandrel (14) for passage and location along a pipe (20) being operated upon by the bending machine (10) an actuator unit (110) according to the present disclosure for driving the mandrel (14) along the pipe (20).

The mandrel actuator unit (110) may comprise: a mandrel connection rod (112) which acts on the mandrel (14), the mandrel connection rod (112) being coupled to the screw rods (116) via the screw nuts (114) of the mandrel actuator unit (110); the mandrel connection rod (112) being configured as a conduit for communicating force generated by rotation of the screw rods (116) to the mandrel (14).

There may also be provided a bending machine (10) for bending pipes (20), the bending machine comprising a mandrel (14) for passage and location along a pipe (20) being operated upon by the bending machine (10) an actuator unit (110) according to the present disclosure for driving the mandrel (14) along the pipe (20), wherein each mandrel screw rod (116) is coupled to a mandrel servo motor (118) via a mandrel gear unit (120) each mandrel servo motor (118) being provided substantially at right angles to the mandrel screw rods (116).

There may also be provided a method of operating a bending machine the bending machine (10) comprising a first servo motor and a second servo motor the method comprising the steps of transmitting a control signal to each of the servo motors to produce substantially the same output; and controlling one of the servo motors in dependence on the output of the other servo motor.

The output may be at least one of torque, angular rotation, position and force.

The bending machine may further comprise a third servo motor, and the method further comprising the step of: controlling two of the servo motors in dependence on the output of the other servo motor.

The output of the servo motors may be co-ordinated so as to deliver a predetermined force to a die for reaction against a pipe, and achieve a predetermined die position.

The output of the servo motors may be co-ordinated so as to deliver a predetermined output to a rotatable bending arm to rotate the bending arm around a central axis to thereby provide bending force for deformation of a pipe, and achieve a predetermined bending arm angular position.

The output of the servo motors may be co-ordinated so as to deliver a predetermined force to a mandrel to insert it into, and extract if from, a pipe, and achieve a predetermined mandrel displacement.

Hence there is provided an actuator unit for a bending machine, and a method of operation of an actuator unit for a bending machine, configured such that the machine's various elements are efficiently packaged to reduce its overall volume and area footprint. The actuator units and bending machine are also configured to enable them to be assembled from standard components.

Brief Description of the Drawings

Examples of the present disclosure will now be described with reference to the accompanying drawings, in which: Figures 1 to 6 illustrate the steps in a typical tube bending process using a

machine according to the present disclosure;

Figure 7 shows a plan view of a tube bending machine according to the present

disclosure;

Figure 8 shows a side view of a bending arm of the bending machine shown in Figure 7; Figure 9 shows a diagrammatic representation of a side view of an actuation unit for a clamp die according to the present disclosure; Figure 10 shows a diagrammatic representation of a plan view of the clamp die actuation unit as shown in Figure 9; Figure 11 shows a diagrammatic representation of a plan view of a pressure die actuation unit for a bending machine of the present disclosure; Figure 12 shows a side view of the pressure die as shown in Figure 11; Figure 13 shows a plan view of a mandrel actuation unit and/or an alternative configuration of a pressure die actuation unit according to the present disclosure; Figure 14 shows a side view of the mandrel actuation unit or pressure die actuation unit as shown in Figure 13; Figure 15 shows a plan view representation of a bending arm actuation unit

according to the present disclosure;

Figure 16 shows a plan diagrammatic view of an alternative mandrel actuation unit configuration to that shown in Figures 14,15; and Figure 17 shows a side view of the mandrel actuation unit as shown in Figure 16.

Detailed Description

Figures 1 to 6 illustrate a process for bending a tube 20 using a bending machine according to the present disclosure. The bending machine 10 comprises a bending (or centre") former 11, a pressure die 12, a clamp die 13, a mandrel 14 with two articulated balls 14a, and a wiper die 15, which holds the tube 20 steady against the mandrel 14. Figures 7,8 show more detailed plan and side views respectively of the bending machine 10, including a bend arm 32 carrying the clamp die 13 and the tooling carrier 30. The bend arm 32 produces rotation of the former 11, whereas the pressure die 12 is fixed to a main bed 22 of the bending machine 10.

Figure 1 shows a tube 20 inserted and ready for bending. In Figure 2 the pressure die 12 and clamp die 13 are closed. The bending former 11 and clamp die 13 then rotate to bend the tube 20, as shown in Figure 3, to pull it through the machine 10. During this process, the pressure die 12 "follows" the tube, which is to say it moves to the left as shown in Figure 3.

The pressure die 12 may consists of a steel or aluminium bar, one side of which is machined to fit halfway round the tube 20 and runs along the straight portion of the tube 20. Alternatively or additionally, the pressure die may comprise other metallic or non metallic materials. This pressure die 12 is free to slide, either by mounting on a roller slide or being mounted directly on a bearing system. During bending, i.e. the rotation of the centre former 11, and hence bending of the straight tube into the circular centre former, the pressure die 12 forms the reaction system necessary to bend the tube.

Thus the only loads on the pressure die 12 are those induced during bending.

For producing bends with a tight radius and/or of high quality, a controlled force, indicated by arrow 21, can be exerted on the pressure die 12 to control its leftward movement by providing a push or drag force.

Figure 4 shows the mandrel 14 being retracted, after which the pressure die 12 is opened and the clamp die 13 drops away, as shown in Figure 5. Finally the bending former 11, pressure die 12, clamp die 13 and the mandrel 14 return to their original locations after the tube 20 is fed forward along the bed 22 of the bending machine 10 and rotated as required for the next bending operation, as shown in Figure 6, or removed from the bending machine 10 if the bending operations are complete.

Figure 7 shows a plan view of the bending machine 10. Figure 8 shows a side view of the bending arm 11 end of the bending machine 10 shown in Figure 7. The table bed 22 defines the major longitudinal length of the bending machine 10. The clamp die 13 and its actuator unit 30 are mounted to a rotatable bending arm 32 which is rotatable with the bending former 11. The pressure die 12 sits opposite the wiper die 15 adjacent the clamp die 13. Unlike the clamp die 13 and bending former 11, the pressure die 12 and wiper die 15 do not rotate with the bending arm 32. The mandrel 14 is mounted to a mandrel actuator unit 110 at the opposite end of the table bed 22 to the bending arm 32. Each of these features will be described in more detail in the

following description and related figures.

Figures 9,10 shows a diagrammatic representation of a side view of the clamp die actuator unit 30. As stated above, this forms part of the apparatus which moves with the bending arm 32 as it moves to deform the tube 20. As shown in Figure 7, the clamp die actuator unit 30 sits facing the bending former 11 along the bending arm 32. The bending former 11 has an arcuate forming surface 40 which is centred on a central axis 42. The clamp die 13 for clamping the tube 20 to the bending former 11 is aligned with the clamp die actuator unit 30, which is operable to drive the clamp die 13 towards and away from the bending former 11. The clamp die actuator unit 30 comprises a clamp die connection rod 46 (or "piston") which acts on the clamp die 13, the clamp die connection rod 13 being coupled to two electrically powered clamp die servo motors 48.

The clamp die connection rod 46 is carried by two clamp die guide rods 50. The clamp die connection rod 46 is driven by the clamp die servo motors 48 along the clamp die guide rods 50.

The clamp die guide rods 50 are provided with a screw thread on their outer circumference to define a clamp die screw rod and the clamp die connection rod 46 is coupled to the clamp die guide rods 50 via a clamp die screw nut 52. Each clamp die screw rod 50 is operable to be driven by one of the clamp die servo motors 48.

Rotation of the screw rod 50 drives the screw nut 52 along the rods 50 to thereby drive the connection rod 46.

Each clamp die screw rod 50 is operable to be driven by one of the clamp die servo motors 48 via a belt or chain 54. That is to say, the servo motor 48 comprises a shaft 56 which extends from the motor 48 and terminates in a drive or gear wheel 57 for connection with the belt 54 which leads to a similar drive or gear wheel 59 on the screw rod 50. One of the belt or chains 54 may be substantially longer than the belt or chain 54 of the other. This is because one servo motor 48 may be located beneath the other, and in one example, for example the arrangement shown in Figure 9, the lower servo motor drives the higher screw rod 50, and the lower screw rod 50 is driven by the higher of the two servo motors 48. In this arrangement one of the clamp die screw rods is vertically above the other clamp die screw rod 50, which are both vertically above one of the clamp die servo motors 48, which in turn is vertically above the other clamp die servo motor 48. That is to say the clamp die screw rods 50 and servo motors 48 are vertically aligned with one another.

Each clamp die servo motor 48 is provided substantially parallel and substantially to one side of the clamp die guide rods 50. The clamp die servo motors 48 are aligned substantially parallel with one another, which is to say they are aligned and adjacent one another and may be provided one above the other. Likewise the clamp die rods 50 are provided parallel with one substantially directly above the other.

The clamp die servo motors 48 may be provided adjacent and beneath, above or to the side of the clamp die rods 50. That is to say the clamp die servo motors 48 may be side by side with the clamp die rods 50. That is to say, the clamp die servo motors 48 are aligned with the clamp die guide rods 50. They may be horizontally aligned, or aligned along a line (or in a direction) at an angle to a direction perpendicular to the plane of the table bed surface 22.

The servo motors 48 are aligned along their longitudinal length and are positioned such that one does not extend substantially beyond the other along their longitudinal length.

Each of the servo motors 48 is connected to a servo drive unit 60 which is fed signals by a computer controlled by 62 operated by control software. Hence the computer 62 sends signals to the servo drive 60 which in turn send signals to the servo motors 48 to turn, and hence drive, the guide rods 50 via the belts 54.

Each of the clamp die servo motors 48 are configured to deliver substantially equal torque output to the clamp die connection rod 46.

In alternative examples (not shown) there may be provided more than two servo motors 48 in combination with additional screw rods 50 and screw nuts 52 to drive the connection rod 46 and hence the clamp die 13. In such examples, the servo motors, rods and nuts may be provided in alignment with one another, that is to say parallel and vertically aligned.

As described above the moveable pressure die 12 is operable to press the tube 20 against the static wiper die 15. This is achieved by a pressure die actuator unit 70 shown diagrammatically in Figures 11 and 12. Figure 11 shows a plan view and Figure 12 shows a side view of this arrangement. The pressure die 12 is moved by the pressure die actuator unit 70 which drives the pressure die 12 towards and away from the wiper die 15. The pressure die actuator unit 70 comprises a pressure die connection rod 72 which acts on the pressure die 12. The connection rod 72 is coupled to two pressure die screw nuts 74, each pressure die screw nut 74 being provided on a pressure die screw rod 76. Each pressure die screw rod 76 is provided with a screw thread on their outer circumference. Each pressure die screw rod 76 is coupled to, and operable to be driven by, a pressure die servo motor 78 by a pressure die gear unit 80.

Each pressure die servo motor 78 is provided substantially at right angles to the pressure die screw rods 76, the gear unit 80 turning the rotational output of the servo motor 78 through 90 degrees to rotatably drive (i.e. rotate) the pressure die screw rods 76 which thus moves the screw nuts 74 along the screw rods 76, thus driving the connection rod 72.

As shown in Figures 13,14 the servo motors 78 may alternatively be provided parallel and to one side, beneath or below the screw rods 76, and the motors 78 and rods 76 may be connected by belts or chains 54 as described in relation to the clamp die actuation unit 30 shown in Figures 9,10. In other respects, however, the features and function of this alternative arrangement is the same as that for the example of Figures 11,12.

In alternative examples (not shown) there may be provided more than two servo motors 78 in combination with additional screw rods 76 and screw nuts 74 to drive the connection rod 72 and hence the pressure die 12. In such examples, the servo motors, rods and nuts may be provided in alignment with one another, that is to say parallel and horizontally aligned.

Each of the pressure die servo motors 78 are configured to deliver substantially equal torque to the pressure die 12.

As with the clamp die actuator unit, each of the servo motors 78 is in communication with a servo drive 82 driven by a computer 84 controlled by control software.

As shown in Figures 7,8,15, the bending machine 10 further comprises a bending arm 32 which in turn comprises the clamp die 13 and clamp die actuator unit 30. The bending arm 32 is rotatably mounted and operable to rotate with the clamp die 13 and the clamp die actuator unit 30 about the centre axis 42 of the bending former 11 to thereby displace the clamp die 13 which pulls the tube 20 around the forming surface of the bending former 11. The clamp die actuator unit 30 is operable to force the clamp die 13 against the bending former 11 while it is being rotated about the central axis 42 of the bending former 11 with the clamp die 13. The bending arm 32 is coupled to a drive mechanism 90, shown generally in Figures 7,8,15, where the drive mechanism 90 is operable to rotate the bending arm 32 about the bending former centre axis 42. As shown in Figures 8,15, the bending arm 32 comprises a shaft 94 which extends perpendicular to the direction in which the actuator clamp die actuator unit 30 and clamp die 13 are aligned. The shaft 94 terminates at its base at a drive wheel 96 which is rigidly coupled to the shaft 94. A plurality of bending arm servo motors 98 are coupled to the shaft 94 via a gearing arrangement including the drive wheel 96. The bending arm servo motors 98 may be engaged with the drive wheel 96 by gear wheels or friction drive wheels 100 as shown in Figures 7,15.

The bending arm servo motors 98 are arranged around the circumference of the drive wheel 96. As shown in Figure 7, 15 one of the bending arm servo motors 98 is arranged underneath the pressure die actuation unit 70, and the other two bending arms servo motors 98 are arranged such that they are underneath the table bed 22. By this arrangement, the bending arm actuation unit 90 and all of its components including the servo motors 98 are within an envelope defined by the table 22 and the immovable pressure die actuation unit housing 70.

Each of the bending arm servo motors 98 are configured to deliver substantially equal torque to the bending arm shaft 94.

In common with the preceding examples of actuation units, each of the bending arm servo motors 98 are linked to a drive unit 102 which in turn are sent commands from a computer 104.

In alternative examples (not shown) there may be provided more than three servo motors 98 in combination with additional gear wheels or friction drive wheels 100 to drive the drive wheel 96.

In such examples, the servo motors and gear/friction drive wheels may be provided under the table 22 and pressure die actuator unit 70 in the same way as those shown in Figure 7.

As shown in Figures 16,17, the bending machine 10 further comprises the mandrel 14 for passage and location along the pipe 20 being operated upon by the bending machine 10. The actuator unit 110 is operable to drive the mandrel 14 along the inside of the pipe 20.

The mandrel actuator unit 110 comprises a mandrel connection rod 112 which acts on the mandrel 14. The mandrel connection rod 112 is coupled to two mandrel screw nuts 114, each mandrel screw nut being provided on a mandrel screw rod 116. Each mandrel screw rod 116 is coupled to a mandrel servo motor 118 via a mandrel gear unit 120. In the example shown, each mandrel servo motor 118 is provided substantially at right angles to the mandrel screw rods 116. As with the pressure die example of Figures 11 and 12, the gear unit 120 translates the rotational output of the motor 118 to drive the mandrel screw rods 116 despite the fact that the servo motors 118 are substantially at right angles to the mandrel screw rods 116. Rotation of the screw rods 116 drives the screw nuts 114, and hence the connection rod 112.

As shown in Figures 13,14 the servo motors 118 may be provided parallel and to one side, beneath or below the screw rods 116 and the motors 118 and rods 116 may be connected by belts or chains 54, as described in relation to the clamp die actuation unit shown in Figures 9,10. In other respects, however, the features and function of this alternative arrangement is the same as that for the example of Figures 16,17.

Each of the mandrel servo motors 118 are configured to deliver substantially equal torque to the mandrel screw rods 116.

As in the preceding examples each of the servo motors 118 is connected to a servo drive 122 which are sent commands from a computer 124. Figure 16 shows a plan view of this arrangement and Figure 17 shows a side view of the same arrangement.

In alternative examples (not shown) there may be provided more than two servo motors 118 in combination with additional screw rods 116 and screw nuts 114 to drive the connection rod 112 and hence the mandrel 14. In such an example, the servo motors, rods and nuts may be provided in alignment with one another, that is to say parallel and horizontally aligned.

For the avoidance of doubt, the servo motors of the present disclosure comprise electrical motors, and may further comprise gear boxes.

Operation of each of the actuation units of the present disclosure is performed according to a common principle. Multiple servo motors are used to drive connection rods or turn the drive wheel 96, and in each case, a signal is transmitted to each of the respective servo motors to produce substantially the same output. That is to say, the servo motors 48 of the clamp die actuation unit 30 will each receive the same control signal requesting them to produce the same power output. At the same time, the servo motors 80 of the pressure die actuation unit 70 will receive a different signal commanding them to produce substantially the same output as one another, but which will not necessarily be the same as that demanded of the servo motors 48 of the clamp die actuator unit 30. Likewise the servo motors 98, 118 of the bending arm actuator 90 and mandrel actuator 110 respectively will each be sent a control signal to produce substantially the same output as their associated servo motors, but not necessarily the same as that of the other actuator units.

For each actuator unit, one of the servo motors is controlled in dependence on the output produced by the other servo motor in the actuator unit, where there may be more than one other servo motor in the actuator unit. That is to say there is a feedback from one of the servo motors which indicates its power output and/or position which is fed via the servo drive and software/computer to the other servo motor(s) of the same actuator unit such that they operate in a coordinated manner.

The output of the actuator unit servo motors is one or more of torque, angular rotation (e.g. position) and force. That is to say, one of the servo motors in each actuator unit is controlled in dependence on the output of the other servo motor(s) where the output which is being used to define the output of the remaining servo motors is at least one of torque, angular rotation and force. As shown in the examples, the bending machine actuator units may comprise at least two servo motors or at least three servo motors.

The output of the servo motors is coordinated so as to deliver a predetermined force to a die, and achieve a predetermined position of the die, for reaction against the tube 20.

This is true for the clamp die 13 or pressure die 12.

Likewise the output of the servo motors 98 of the bending arm 32 are coordinated so as to deliver a predetermined output to the rotatable arm 94 to rotate the arm 94 about the central axis 42 to thereby provide a bending force for deformation of the tube 20.

Likewise with the mandrel actuation unit 110, the output of the servo motors 118 is coordinated so as to achieve a predetermined angular rotation and deliver a predetermined force to the mandrel 14 to be inserted into, and extracted from, the tube 20, and thereby achieve a predetermined amount of displacement of the mandrel.

Each of the units of the bending machine 10 comprise actuation units configured to be as compact as possible.

For example, the guide rods 50 and servo motors 48 of the clamp die actuation unit 30 are arranged on top of one another such that they fit within a relatively small volume and have a relatively small area footprint. By contrast, consider if the servo motors 48 were to extend outwards from the guide rods 50, so as to be aligned with the guide rods 50, then the bending arm 32 segment of the bending machine would be substantially longer than that of the present disclosure because of the additional length of the servo motors 48. Additionally, since multiple servo motors 48 are coupled to the clamp die connection rod 13, this means the servo motors 48 can be smaller than if one were used, thus having an impact on the overall size of the machine.

Likewise, with the pressure die actuation unit 70, since the servo motors 78 are provided at right angles to the guide rods 76 such that they are pointing downwards, or the servo motors 78 are provided such that they are underneath and vertically aligned with the guide rods 76. Eiher configuration reduces the length of the pressure die actuation unit assembly 70, keeping the size of the bending arm machine 10 as a whole to a minimum. The same is true of the mandrel actuation unit 110.

Additionally since the bending machine of the present disclosure comprises a plurality of servo motors of a standard design, rather than a specialised high performance bespoke design, the overall cost of the machine is reduced. Likewise the incorporation of multiple screw rods 50, 76,116 instead of a single screw rod, means that off the shelf" screw rods may be procured, thereby obviating the need for design and procurement of larger bespoke diameter rods which would be inherently more time consuming and costly to obtain.

Reducing the overall length of the machine can be critical to some users of tube bending machines. Utilising the actuator unit configurations of the present disclosure may reduce the length and width of the machine by at least a metre.

The use of several servo motors 98 in the bending arm drive mechanism 90 means that the torque can be applied to the drive wheel 96 without the need for a single servo motor of a higher specification. Additionally, using several servo motors to act upon the drive wheel 96 means that the contact between the drive wheel 96 and the different gear wheels 110 coupled and driven by the servo motors 98 means that less stress is placed upon the drive wheel at the interface between the gear wheels 100 and the drive wheel 96, thereby increasing the life of the drive wheel 96 and gear wheels 100. The location of the servo motors 98 lends itself to a compact design.

The configuration of the present disclosure also provides a machine which is relatively squat (i.e. short) compared to machines of the related art. Thus the bending machine of the present disclosure may be provided on a shop floor without the need for excavation or a platform on which an operator can walk.

The provision of the drive wheel 96 and servo motors 98 arrangement at the bottom of the bend head allows full operator access and visual monitoring of the bend tooling, as well as reducing the diameter of the bend arm shaft 94.

Reducing the bend arm shaft diameter provides further advantage of reducing the width and length of the bend arm allowing the operator to reduce the length of straights between bends in the tube, thereby increasing design flexibility.

The method of operation, which given the new configuration defined above requires for special control of the various servo motors such that a coordinated operation is achieved, allows for a higher overall output than would be possible with conventional servo motors, as well as smaller overall bending machine size.

Attention is directed to all papers and documents which are filed concurrently with or previous to this specification in connection with this application and which are open to public inspection with this specification, and the contents of all such papers and documents are incorporated herein by reference.

All of the features disclosed in this specification (including any accompanying claims, abstract and drawings), and/or all of the steps of any method or process so disclosed, may be combined in any combination, except combinations where at least some of such features and/or steps are mutually exclusive.

Each feature disclosed in this specification (including any accompanying claims, abstract and drawings) may be replaced by alternative features serving the same, equivalent or similar purpose, unless expressly stated otherwise. Thus, unless expressly stated otherwise, each feature disclosed is one example only of a generic series of equivalent or similar features.

The invention is not restricted to the details of the foregoing embodiment(s). The invention extends to any novel one, or any novel combination, of the features disclosed in this specification (including any accompanying claims, abstract and drawings), or to any novel one, or any novel combination, of the steps of any method or process so disclosed.

Claims

CLAIMSAn actuator unit (30, 70, 110) for a bending machine (10) for bending pipes (20), wherein the actuator unit (30) comprises two guide screw rods (50, 76, 116); two servo motors (48, 78, 118); one of the servo motors being coupled to one of the guide screw rods (50, 76, 116), the other servo motor being coupled to the other guide screw rod (50, 76, 116), each servo motor (48, 78, 118) operable to rotate the screw rod (50, 76, 116) to which it is coupled.
2 An actuator unit (30, 70, 110) for bending pipes (20) as claimed in claim 1 wherein each servo motor (48, 78, 118) is provided substantially parallel and substantially to one side of the screw rod (50, 76, 116) to which it is coupled.
3 An actuator unit (30, 70, 110) as claimed in claim 1 or claim 2 wherein the servo motors (48, 78, 118) are arranged aligned parallel with one another.
4 An actuator unit (30, 70, 110) as claimed in any one of the preceding claims wherein each of the servo motors (48, 78, 118) are configured to deliver substantially equal torque to their respective screw rods (50, 76, 116).
An actuator unit (30, 70, 110) as claimed in any one of the preceding claims wherein a screw nut (52, 74, 114) is rotatably engaged with each of the screw rods (50, 76, 116); and each of the screw nuts (52, 74, 114) are operable to be driven along their respective screw rod (46) by rotation of the screw rod.
6 An actuator unit (30, 70, 110) as claimed in any one of the preceding claims wherein the servo motors (48, 78, 118) are substantially aligned with the screw rods (50, 76, 116).
7 An actuator unit (30, 70, 110) as claimed in any one of the preceding claims wherein the servo motors (48, 78, 118) are provided beneath or above the screw rods (50, 76, 116).
8 An actuator unit (30, 70, 110) as claimed in any one of claims 1 to 7 wherein the servo motors (48, 78, 116) are substantially vertically aligned with the screw rods (50, 76, 116).
9 An actuator unit (30, 70, 110) as claimed in any one of claims 1 to 7 wherein the servo motors (48, 78, 118) are substantially horizontally aligned with the screw rods (50, 76, 116).
An actuator unit (30, 70, 110) as claimed in any one of the preceding claims wherein each screw rod (50, 76, 116) is coupled to, and driveable by, one of the servo motors (48, 78, 118) via a belt or chain (54).
11 A bending machine (10) for bending pipes (20), the bending machine comprising: a bending former (11) having a forming surface (40) which is centred on a central axis (42); a clamp die (13) for clamping a pipe (20) to the bending former (11); and an actuator unit (30) as claimed in any one of claims 1 to 10 for driving the clamp die (13) to/from the bending former (11).
12 A bending machine (10) as claimed in claim 11, wherein the actuator unit (30) further comprises: a clamp die connection rod (46) which acts on the clamp die (13); the clamp die connection rod (46) being coupled to the screw rods (50) via the screw nuts (52); the clamp die connection rod (46) being configured as a conduit for communicating force generated by rotation of the screw rods (50) to the clamp die (13).
13 A bending machine (10) as claimed in claim 11 or claim 12 further comprising a bending arm (32) which comprises the clamp die (13) and clamp die actuator unit (30), and the bending arm (32) is rotatably mounted and operable to rotate with the clamp die (13) and the clamp die actuator unit (30) about the central axis (48) of the bending former (11) to thereby displace the clamp die (13) around the forming surface (40) of the bending former (11), the clamp die actuator unit (30) being operable to force the clamp die (13) against the bending former (11) while it is being rotated about the central axis (42) of the bending former (11) with the clamp die (13).
14 A bending machine (10) as claimed in claim 9 wherein the bending arm (32) is coupled to a drive mechanism (90) operable to rotate the bending arm (32) about the bending former central axis (42) the bending arm drive mechanism comprising a shaft (94) aligned with the bending former central axis (42), wherein the shaft extends perpendicular to the direction in which the clamp die actuator unit (30) and clamp die (13) are aligned; and a plurality of bending arm servo motors (98) operable to rotate the shaft (94) to thereby drive the bending arm (32) about the bending former central axis (42).
A bending machine as claimed in any one of the preceding claims wherein each of the bending arm servo motors (98) are configured to deliver substantially equal torque to the bending arm shaft (94).
16 A bending machine (1 0) for bending pipes (20), the bending machine comprising a moveable pressure die (12) operable to move to a position to engage with a pipe (20); an actuator unit (70) as claimed in any one of claims 1 to 10 for driving the pressure die (12) to the pipe engagement position.
17 A bending machine (10) as claimed in claim 16 wherein; the pressure die actuator unit (70) comprises a pressure die connection rod (72) which acts on the pressure die (12), the pressure die connection rod (72) being coupled to the screw rods (76) via the screw nuts (74) of the pressure die actuator unit (70); the pressure die connection rod (72) being configured as a conduit for communicating force generated by rotation of the pressure die screw rods (76) to the pressure die (12).
18 A bending machine (10) for bending pipes (20), the bending machine comprising a moveable pressure die (12) operable to move to a position to engage with a pipe (20); an actuator unit (70) as claimed in any one of claims 1 to 6 for driving the pressure die (12) to the pipe engagement position wherein each screw rod (76) of the pressure die actuator unit is coupled to its respective servo motor (78) via a pressure die gear unit (80); each pressure die servo motor (78) being provided substantially at right angles to the pressure die screw rods (76).
19 A bending machine (10) for bending pipes (20), the bending machine comprising a mandrel (14) for passage and location along a pipe (20) being operated upon by the bending machine (10) an actuator unit (110) as claimed in any one of claims 1 to 10 for driving the mandrel (14) along the pipe (20).
A bending machine (10) as claimed in claim 19 wherein the mandrel actuator unit (110) comprises a mandrel connection rod (112) which acts on the mandrel (14), the mandrel connection rod (112) being coupled to the screw rods (116) via the screw nuts (114) of the mandrel actuator unit (110); the mandrel connection rod (112) being configured as a conduit for communicating force generated by rotation of the screw rods (116) to the mandrel (14).
21 A bending machine (10) for bending pipes (20), the bending machine comprising a mandrel (14) for passage and location along a pipe (20) being operated upon by the bending machine (10) an actuator unit (110) as claimed in any one of claims 1 to 6 for driving the mandrel (14) along the pipe (20), wherein each mandrel screw rod (116) is coupled to a mandrel servo motor (118) via a mandrel gear unit (120) each mandrel servo motor (118) being provided substantially at right angles to the mandrel screw rods (116).
22 A method of operating a bending machine the bending machine (10) comprising a first servo motor and a second servo motor the method comprising the steps of transmitting a control signal to each of the servo motors to produce substantially the same output; and controlling one of the servo motors in dependence on the output of the other servo motor.
23 A method of operating a bending machine as claimed in claim 22 wherein the output is at least one of torque, angular rotation, position and force.
24 A method of operating a bending machine as claimed in claim 22 or claim 23 wherein the bending machine further comprises a third servo motor, and the method further comprising the step of: controlling two of the servo motors in dependence on the output of the other servo motor.
A method of operating a bending machine as claimed in any one of claims 22 to 24 wherein the output of the servo motors is co-ordinated so as to a) deliver a predetermined force to a die for reaction against a pipe, and b) achieve a predetermined die position.
26 A method of operating a bending machine as claimed in any one of claims 22 to 24 wherein the output of the servo motors is co-ordinated so as to deliver a predetermined output to a rotatable bending arm to rotate the bending arm around a central axis to thereby provide bending force for deformation of a pipe, and achieve a predetermined bending arm angular position.
27 A method of operating a bending machine as claimed in any one of claims 22 to 24 wherein the output of the servo motors is co-ordinated so as to deliver a predetermined force to a mandrel to insert it into, and extract if from, a pipe, and achieve a predetermined mandrel displacement.
28 An actuator unit for a bending machine for bending pipes substantially as hereinbefore described and/or as shown in the accompanying drawings.
29 A bending machine substantially as hereinbefore described and/or as shown in the accompanying drawings.A method of operation of a bending machine substantially as hereinbefore described and/or as shown in the accompanying drawings.