TOOLS FOR APPLYING TORQUE

Abstract

Disclosed is a tool for applying torque to an object, the tool comprising: a frame for clamping to the object to which torque is to be applied, the frame comprising a pair of jaws with an adjustable separation therebetween, and an adjuster mechanism to adjust the separation between the jaws; at least one thruster disposed on opposite sides of an intended axis of rotation of the frame, respective thrusters providing thrust in opposite directions, so as to cooperate and generate torque on the frame; characterised in that a displaceable mass is provided within a barrel extending from at least one of said thrusters, which mass is displaced by the thruster upon actuation, so as to increase the recoil, and hence the torque, experienced by the frame upon actuation of the thruster.

Claims

1. A tool for applying torque to an object, the tool comprising: a frame for clamping to the object to which torque is to be applied, the frame comprising a pair of jaws with an adjustable separation therebetween, and an adjuster mechanism to adjust the separation between the jaws; at least one thruster disposed on opposite sides of an intended axis of rotation of the frame, respective thrusters providing thrust in opposite directions, so as to cooperate and generate torque on the frame; characterised in that a displaceable mass is provided within a barrel extending from at least one of said thrusters, which mass is displaced by the thruster upon actuation, so as to increase the recoil, and hence the torque, experienced by the frame upon actuation of the thruster.

2. A tool according to claim 1, wherein each thruster comprises a charge of propellant or explosive.

3. A tool according to claim 2, wherein the charge may be electrically initiated remotely.

4. A tool according to claim 1, wherein the displaceable mass comprises a piston within the bore of the barrel.

5. A tool according to claim 4, wherein the piston is formed from a material which is selected and shaped so as to have a substantially gas-tight seal with the interior surface of the barrel once the charge has been initiated.

6. A tool according to claim 4, wherein the piston substantially comprises or consists of a synthetic plastics material, especially a moulded plastics material.

7. A tool according to claim 4, wherein the piston substantially comprises or consists of high-density polyethylene (HDPE).

8. A tool according to claim 1, wherein the displaceable mass comprises a body of liquid.

9. A tool according to claim 8, wherein the liquid is water or an aqueous solution.

10. A tool according to claim 4, wherein the tool further comprises a resistance which tends to resist displacement of the displaceable mass.

11. A tool according to claim 10, wherein the resistance is provided by a body of liquid as defined in claim 8, located within the barrel between the piston and an end cap covering the barrel.

12. A tool according to claim 11, wherein the liquid substantially fills the volume of the barrel between the piston and the end cap.

13. A system for applying torque to an object, the system comprising a tool in accordance with claim 1, together with one or more of the following: a set of a plurality of single-use caps for capping the distal end of the barrel; and a set of a plurality of single-use deformable pistons.

14. A method for applying torque to an object, the method comprising the steps of: a) adjusting the separation between the jaws of a tool in accordance with claim 1, by means of the adjuster mechanism, so as to clamp the device to the object; b) placing a cap over the distal end of at least one barrel; and c) causing the initiation of the thrusters.

15. A method for applying torque to an object in accordance with claim 14, the method additionally comprising the step (ai) of: substantially filling, with a liquid, the volume of the barrel downstream of the distal end of a piston located therein.

16. A method for applying torque to an object lying underwater, the method comprising the steps of: a) adjusting the separation between the jaws of a tool in accordance with claim 1, by means of the adjuster mechanism, so as to clamp the device to the object; b) allowing the water to fill the barrel downstream of the piston; and c) causing the initiation of the thrusters.

17. A method according to claim 14, wherein the object is the tail fuse or nose fuse of a bomb or other munition.

Description

[0022] The invention will now be further described by way of illustrative embodiments and with reference to the accompanying drawing figures in which:

[0023] FIGS. 1A and 1B show two different embodiments of prior art known “rocket wrench” devices in situ attached to the nose fuse of an unexploded bomb;

[0024] FIG. 2 shows a sectional view of part of one embodiment of a device in accordance with the invention; and

[0025] FIGS. 3A and 3B show two different embodiments of a device in accordance with the first aspect of the invention in situ, attached to the nose fuse of an unexploded bomb.

EXAMPLES

Example 1

Description of the Prior Art

[0026] Referring to FIG. 1A, there is shown a conventional prior art “rocket wrench” device clamped to the nose fuse of an unexploded bomb (2). The rocket wrench device comprises a steel frame (4), provided with a pair of jaws (6a, 6b). The separation between the jaws (6, 6a) can be adjusted by means of an adjuster mechanism comprising a pair of knurled wheels (8a, 8b), each wheel mounted on a respective shaft (9) which is in screw-threaded engagement with an end region of each of the jaws (6a, 6b). A pair of thrusters 10a 10b is also provided on the frame, located at the outer edge thereof (so as to maximise turning moment on the frame). The thrusters 10 take the form of a rocket tube (comprising a propellant charge) and a venturi. One thruster 10 is provided on each side of the axis of intended rotation of the frame, with thrusters 10a, 10b pointing in opposite directions, so as to cooperate and provide torque on the frame when the thrusters are actuated. The direction of rotation of the frame is indicated by the arrows (12) marked thereon. It will be noted that the direction of rotation is anticlockwise, so as to cause the fuse to be unscrewed from the bomb (2). Wires (14) are visible which are to permit the electrical initiation of the propellant charge in the thrusters 10 to be performed remotely from a safe distance. Finally, bungee cords 16 are attached to the frame to allow the fuse to be withdrawn from the bomb, again from a safe distance, once the fuse has been unscrewed.

[0027] FIG. 1B illustrates a similar prior art “rocket wrench” device but, in this embodiment, the frame is provided with four thrusters 10, with one pair of thrusters being provided on each side of the frame.

Example 2

Detailed Description of an Embodiment of the Invention

[0028] FIG. 2 is a sectional view of part of an embodiment of a device in accordance with the present invention. Parts of the device are similar to the prior art device shown in FIG. 1A, and like components are denoted by common reference numerals. The device comprises a steel frame 4, part of which is apparent in the Figure. The frame 4 is provided with a pair of adjustable jaws, (not shown in FIG. 2), by which the frame can be clamped onto the tail or nose fuse of a bomb or other object to which torque is to be applied. The separation between the adjustable jaws can be altered using an adjuster mechanism, which comprises a pair of knurled wheels, each of which is mounted on a respective shaft, which is in screw-threaded engagement with an end region of each of the jaws, generally as illustrated in FIGS. 1A, 1B. This allows both the relative angle, and the separation, between the jaws to be altered.

[0029] As with the prior art device, a pair of thrusters is also provided on the frame, located at the outer edge thereof (so as to maximise turning moment on the frame). One such thruster, 10, is shown in FIG. 2. The thrusters 10 comprise a rocket tube 11 and a venturi 13. The rocket tube includes a breech 30, which is sealed at a proximal end thereof by breech plug 32. Within the breech is a blank .50 cal cartridge 34, the propellant of which provides the thrust. The cartridge is fired by an electrical initiator which enters the device via the breech plug 32 and activates initiation means located in the base of the cartridge. In addition, each thruster also has a respective barrel 20 screwed onto the distal end of the thruster. Each barrel is made of steel and is 30 mm in diameter and about 60-80 mm long. A displaceable mass is provided within the barrel, which mass is displaced by the thruster upon actuation, so as to increase the recoil, and hence the torque, experienced by the frame upon actuation of the thruster.

[0030] In the illustrated embodiment, the displaceable mass takes the form of a piston 22 seated within the bore of the barrel. The piston is formed from a material which is selected and shaped so as to have a substantially gas-tight seal with the interior surface of the barrel once the charge has been initiated. Specifically, the piston advantageously undergoes a deformation when the charge is initiated, the force on the piston exerted by the charge tending to cause the piston to deform in such a way as to cause the piston to create a gas-tight seal with the interior surface of the barrel. In the illustrated embodiment, the piston is formed from moulded HDPE and has a concave surface facing the propellant charge. When the propellant charge is fired, the expanding gases generated tend to force the thin edges of the piston outwards, into contact with the interior surface of the barrel 20, so as to form a gas-tight seal therewith. At the distal, “downstream” end of the barrel 20 is a plastics cap 24, which is in screw -threaded engagement with, and seals the end of, of the barrel. Further, between the piston 22 and the cap 24, the interior of the barrel 20, the tool comprises a resistance 26 which tends to resist the displacement of the piston. The resistance may be provided by a gas but, more preferably, is provided by a liquid, since liquids are far less compressible than gases. Thus, in the illustrated embodiment, the interior of the barrel 20, “downstream” of the piston 22, is filled completely with water, kept in place in the barrel 20 by the piston 22 and the cap 24.

[0031] Referring to FIG. 3A, there is shown an embodiment of a device in accordance with the invention, clamped to the nose fuse of an unexploded bomb. Parts of the device are similar to the prior art device shown in FIG. 1A, and like components are denoted by common reference numerals.

[0032] Similarly, FIG. 3B shows a second embodiment of a device in accordance the invention, clamped to the nose fuse of an unexploded bomb. Parts of the device are similar to the prior art device shown in FIG. 1B, and like components are denoted by common reference numerals. The embodiment is essentially similar to that shown in FIG. 3A, but differs in that the device comprises four thrusters in total, with one pair of thrusters provided on each of the two opposed sides of the frame.