GB2123328A

GB2123328A - A hydraulic torque machine

Info

Publication number: GB2123328A
Application number: GB08313426A
Authority: GB
Inventors: James Muir; Joseph Ashbridge; William A Thomson; Sam Mccartney; Frank Mcluskie; Arthur Milne
Original assignee: MACH TOOL ENGINEERS
Current assignee: MACH TOOL ENGINEERS
Priority date: 1982-05-15
Filing date: 1983-05-16
Publication date: 1984-02-01
Also published as: GB8313426D0; GB2123328B

Abstract

A reaction chuck 31 and a rotating chuck 21 are mounted on a machine base and are adapted to grip respective ones of a pair of tubes. The rotating chuck is capable of complete rotation about the axis of said tubes and the reaction chuck is free to slide longitudinally of the base. The reaction chuck is capable also of limited rotational movement and includes torque sensing means to measure the torque applied to the joint of the tubes. To ensure accurate centring of the tubes, the chucks are each provided with a self centring arrangement comprising a ring-shaped cam plate 50 having three equispaced arcuate slots 51. A cam follower 52 which is connected to a piston of a radially extending clamping cylinder runs in each of the slots. Each chuck comprises six clamping cylinders with only three being connected to the centring arrangement. <IMAGE>

Description

SPECIFICATION Hydraulic torque machine This invention relates to a hydraulic torque machine and in particular to a machine for use in the making and breaking of threaded connections between tubular members.

According to the present invention there is provided a hydraulic torque machine comprising a machine base, a reaction chuck adapted to grip a first tube body and a rotating chuck adapted to grip a second tube body axially aligned with said first tube body, the rotating chuck being capable of complete rotation about the axis of said bodies and means for effecting rotation of the rotating chuck.

Preferably said reaction chuck is free to slide longitudinally on said machine base.

Preferably also, said means for effecting rotation of the rotating chuck comprises a pair of hydraulic motors.

According to a further aspect of the present invention, the reaction chuck is capable of limited rotational movement and a torque sensing means is incorporated to measure the torque applied to the joint of the first and second tube bodies.

Preferably, said torque sensing means includes a load ceil.

Preferably also, an output signal from said load cell controls the hydraulic power to the hydraulic motors through a proportional control valve.

According to a third aspect of the present invention there is provided a self centring chuck arrangement for gripping pipes or the like, the arrangement comprising a plurality of radially extending clamp cylinders, the pistons of which connect with engagement pins having followers cooperating with respective grooves in a cam plate to ensure each piston moves by the same amount.

Preferably, said cam plate has a ring profile and said grooves are in the form of substantially radially extending arcuate slots.

Embodiments of the present invention will now be described, by way of example with reference to the accompanying drawings, in which: Figure lisa side elevational view of one embodiment of a hydraulic torque machine made in accordance with the present invention; Figure2 is a part plan view of the machine of Figure 1; Figure 3 is an end elevational view illustrating the rotating chuck; Figure 4 is a section view along the line A-A of Figure 1 illustrating the reaction chuck; Figure 5 shows details of fixing of load cell to the reaction chuck assembly; Figures 6a, 6b, 6e and 6d show details of the rotating hydraulic coupling fitted to the rotating chuck assembly; Figure 7 is a hydraulic circuit diagram of the machine of Figure 1;; Figure 8 illustrates an electrical circuit diagram for the electrical control system ofthe machine of Figure 1; Figures 9, 10 and 11 are plan, side elevation and end views of the reaction clamp assembly support frame; Figure 12 shows in part elevation the cam plate of the self centring chuck arrangement; and Figure 13 is a detail of engagement pin and followers arrangement.

Referring to the drawings a hydraulic torque machine 1 comprises a machine base 10, a rotating chuck assembly 20 and a reaction chuck assembly 30.

The rotating chuck assembly 20 is fixed to one end of the machine base 10 and includes a rotating clamp assembly 21 adapted for rotation within support plates 22a and 22b on suitable bearings. The clamp assembly 21 comprises six radially extending hydraulic clamps which serve to grip one of the tube bodies of the pair of tubes to be connected or broken. The clamp assembly 21 is fixed to an externally toothed gear ring 24 which is engaged and rotated by pinions 25a, 25b of respective hydraulic motors 23a, 23b fitted on a support plate 26. Hydraulic power is fed from a power pack and control unit 40 to the hydraulic motors 23a and 23b and, via a hydraulic rotary distribution ring 27, to the hydraulic clamp assembly 21.

The reaction chuck assembly 30 is adapted to slide longitudinally of the machine base 10 by virtue of castors 39 and may be located at any desired position along the length of the base 10. The reaction chuck assembly 30 includes a clamp assembly 31 similar to the clamp assembly 21 of the rotating chuck 20. The clamp assembly 31 is free to effect limited rotary motion and to this end is rotatably mounted on suitable bearings between support plates 32a, 32b. A load cell 34, which limits the extent of rotation of the clamp assembly 31 is provided on the chuck assembly 30. One end of the cell 34 is connected to a plate 36 joining flanges 33 on the clamp assembly and the other end of the cell 34 is connected to a plate 37 joining support plates 32a, 32b. Hydraulic power for the hydraulic clamp assembly is fed from the power pack 40 via a power loop 45.

To ensure accurate centring of the tube within the clamp assemblies 21 and 31, each assembly is provided with a self centring arrangement which comprises a ring shaped cam plate 50 having three equispaced substantially radially extending arcuate slots 51, only one of which is shown in Figure 12. A follower 52 runs in each slot and is connected via pin 53 to a respective piston of the clamp assembly. The pin 53 is constrained to move in a radial slot 54 in the clamp assembly support frame 60 (Figure 10). Thus, movement of one of the pistons causes rotation of the cam plate resulting in simultaneous movement of the other two pistons connected to the cam plate.

It has been found that, in a six piston arrangement, only three of the pistons need be connected to the cam plate. This ensures ease of operation and still results in accurate centring. To prevent operation of the other three "free" clamps, check valves 70a, 70b are included inhibiting operation of the "free" pistons until the "controlled" pistons have clamped the pipe with a sufficient pressure determined by the setting of the check valves 70a, 70b.

The machine of the present invention operates as follows, the description by way of example, considering the joining of two tube bodies.

The reaction chuck assembly 30 is positioned as desired and the first pipe clamped to the desired pressure as described below, this pressure being selected automatically by the control system. Simi marly the second pipe is clamped within the rotating chuck assembly 20. The rotating chuck assembly is caused to rotate until the load cell 34 registers the pre-determined torque applied across the joint whereby the hydraulic power to the hydraulic motors 23a, 23b is controlled via proportional control valve 71.

More specifically, the operation of the machine of the invention will now be described with particular reference to Figures 7 and 8.

Operating Sequence POWER ON energises displays, signal conditioning and control circuits. After a delay (0.5 seconds to 20 seconds) the unloading valve operates and loads the pump.

The control circuits are initially in the AUTO mode and in the STOP condition, with MAKE UP selected.

The chuck control valves are de-energised. The displays indicate the SET TORQUE and CLAMP PRESSURE (calculated in torque units).

To set the required torque, the ten turn potentiometer is adjusted until the required valve is indicated on the torque display. The direction of "motor rotation" is selected by pressing the MAKE UP or BREAK OUT push button.

The chucks are clamped and the clamp pressure is set to correspond to the required torque by means of the relief valve.

The motor is started by operating the RUN button.

In MAKE UP Mode, the motor runs until the torque measured by the load cell reaches the set valve. The proportional valve then closes down until the flow to the motor is just sufficient to make up leakage. The actual torque is displayed on the appropriate display. In BREAK OUT Mode, the proportional valve opens sufficiently for the torque to reach the set valve. If this is sufficient to unscrew the pipe, the motor rotates and the valve opens fully. If the torque is insufficient to unscrew the pipe, the motor remains stalled and leakage is made up via the proportional valve to maintain the set torque.

The chucks cannot be released while RUN Mode is operative.

If required, the actuai torque at which the system stabilizes in MAKE UP Mode can be printed by operating the appropriate button on the printer, which temporarily latches the valve displayed by the torque unit.

Operation of the STOP button causes the proportional valve to close and the torque set point is restored to the torque display.

Once STOP Mode has been selected, the chucks can be released by the appropriate RELEASE buttons. These are momentary contact switches which give 'inching' control of the release.

If MANUAL Mode is selected, the RUN and STOP buttons become inoperative. The torque display indicates the set torque, but this isnot relevant to the MANUAL mode.

While in MANUAL ModetheiNCH buttonçaAn-be used to rotate the rotary chuck. The direction of rotation is determined by the MAKEUP and BREAK OUT button.

In MAN UAL Mode, the chucks can be operated without restriction.

The EMERGENCY STOP. button disconnects power from the control circuits and unloads the pump. The motor will stop and the chucks will be held in their existing condition.

The display and signal conditioning units remain energised.

On restoring power the control unit will again be initialised to the AUTO, STOP, MAKE UP condition.

Modifications and improvements may be incorporated without departing from the scope of the invention.

Claims

1. A hydraulic torque machine comprising a machine base, a reaction chuck adapted to grip a firsttube body and a rotating chuck adapted to grip a second tube body axially aligned with said first tube body, the rotating chuck being capable of complete rotation about the axis of said bodies and means for effecting rotation of the rotating chuck.

2. A machine as claimed in Claim wherein said reaction chuck is free to slide longitudinally on said machine base.

3. A machine as claimed in either preceding Claim wherein said means for effecting rotation of the rotating chuck comprises a pair of hydraulic motors.

4. A machine as claimed in any preceding Claim wherein the reaction chuck is capable of limited rotational movement and a torque sensing means is incorporated to measure the torque applied to the joint of the first and second tube bodies.

5. A machine as claimed in Claim 4 wherein said torque sensing means includes a load cell.

6. A machine as claimed in Claim 5 wherein an output signal from said load cell controls the hydraulic power to the hydraulic motors through a proportional control vajve.

7. A self centring chuck arrangement for gripping pipes or the like, the arrangement comprising a plurality of radially extending clamp cylinders, the pistons of which connect with engagement pins having followers cooperating with respective grooves in a cam plate to ensure each .piston moves by the same amount.

8. A chuck arrangement as claimed.in.Claim 7 wherein said cam plate has a ring profile and said grooves are in the form of substantially radially extending arcuate slots.

9. A hydraulic torque machine substantially as hereinbefore described with reference to the accompanying drawings.

10. A self centring chuck arrangement for gripping pipes or the like substantially as hereinbefore described with reference to the accompanying drawings.