GB2573169A

GB2573169A - A drive link

Info

Publication number: GB2573169A
Application number: GB1806947.6A
Authority: GB
Inventors: Johnson Mike
Original assignee: Hire Torque Ltd
Current assignee: Hire Torque Ltd
Priority date: 2018-04-27
Filing date: 2018-04-27
Publication date: 2019-10-30
Also published as: GB201806947D0

Abstract

A torque wrench drive link 20 containing a housing, a drive plate 3 and an actuator coupling to attach an actuator 4 to the housing. The housing comprises at least two interlocking parts 20a and 20b, which contain an internally splined opening to allow mounting of a reaction arm 8. The interlocking parts also shield and enclose the drive plate 3 to eliminate pinch points (p, fig 1b and1c) that could cause injury or fingers to become trapped in the gap. This shroud also prevents access to the drive plate 3 when the torque wrench drive link 20 is coupled to the actuator 4. The interlocking parts could include at least one recess 22e and 22f, at least one protrusion and one key (22c and 22d, fig 4b) that align to allow the parts to engage with each other. The drive link could be secured by a plurality of fasteners such as externally threaded bolts or screws, which pass through a plurality of aligning through holes in the interlocking parts. The torque wrench could contain a ratchet drive 5 mounted in the drive plate, an externally splined hollow shaft and a socket attachable to a socket connector.

Description

A Drive Link

Field of the Invention

The present invention relates to a drive link and in particular to a ratchet drive driven by a powered actuator.

Background of the Invention

Drive links for torque wrenches which are typically hydraulically powered, are comprise a housing which is machined from a single billet, usually formed of aluminium. In order to mount a drive plate in the housing a slot is provided between two bosses. The drive plate is assembled in the housing by sliding the drive plate through the slot. However, the resulting assembly presents pinch points.

Hydraulic torque wrenches are often used to turn large nuts/bolts, typically for connecting together the flanges of adjacent pipes of a pipeline. The forces exerted by the torque wrenches can be very great and often the external environment is hostile. If a user’s finger becomes trapped in a machine the user could be badly harmed. It would be desirable to provide a hydraulic torque wrench which eliminates the pinch points associated with the prior art devices.

Summary of the Invention

According to the invention there is provided a torque wrench drive link comprising a housing, a drive plate mounted for rotation in the housing and an actuator coupling, the actuator coupling providing for attachment of an actuator to the housing, wherein the housing comprises at least two interlocking parts, each interlocking part including an internally splined opening for mounting a reaction arm, and wherein the at least two interlocking parts of housing provide a shroud which encloses the drive plate in the housing and prevents access to the drive plate when the torque wrench drive link is coupled to the actuator.

Preferably, one interlocking part includes at least one protrusion and another other interlocking part includes at least one recess, the at least one protrusion and at least one recess so shaped and dimension as to engage with one another and prevent relative rotation between the interlocking parts. Alternatively, each interlocking part may include at least one recess and a key may be situated in aligned recesses of adjacent interlocking parts.

The at least two interlocking parts may be secured together by a plurality of fasteners.

Preferably, each of the fasteners includes an externally threaded bolt or screw.

One of the interlocking parts may include a plurality of through holes, and another of the interlocking parts includes a corresponding plurality of internally threaded holes which align with the through holes, the fastener passing through one of the through hole engages with internal threads of the aligned hole.

According to another aspect of the invention there is provided a torque wrench comprising a torque wrench drive link according to the first aspect of the invention, an actuator in driving connection with the drive plate, a ratchet drive mounted within the drive plate, a reaction arm and means for mounting the reaction arm to the internally splined opening of at least one of the interlocking parts.

Advantageously, the means for mounting the reaction arm to the internally splined opening of at least one of the interlocking parts includes an externally splined hollow shaft.

The torque wrench may further comprise a socket attachable to a socket connector, the socket connector in driving connection with the ratchet drive.

Brief Description of the Drawings

In the Drawings, which illustrate drive links of the prior art, and a drive link and torque wrench of preferred embodiments of the invention:

Figure 1a is a schematic representation of a drive link of the prior art;

Figure 1b is a detailed schematic representation of a part of the drive link illustrated in

Figure 1a;

Figure 1c is a cross-sectional elevation of the drive link illustrated in Figure 1a;

Figure 2a is a schematic representation of an assembled torque wrench including a drive link and according to the invention viewed from a first side;

Figure 2b is a schematic representation of the assembled torque wrench and drive link illustrated in Figure 2a viewed from an opposing side;

Figure 3a illustrates the interlocking parts of the housing of the drive link illustrated in

Figures 2a and 2b viewed from a first side;

Figure 3b illustrates the interlocking parts of the housing of the drive link illustrated in

Figures 2a and 2b from viewed from an opposing side; and

Figure 4a is a schematic cross-section illustrating an assembled torque wrench illustrated in

Figures 2a and 2b;

Figure 4b is an exploded view of the assembled torque wrench illustrated in Figure 4a viewed from a first side; and

Figure 4c is an exploded view of the assembled torque wrench illustrated in Figure 4a viewed from an opposing side.

Description of the Prior Art

Referring to Figures 1a to 1c, there is shown a hydraulic torque wrench 1 of the prior art.

The principal components of the wrenchl are known in the art as a drive link 2, a drive plate 3 that is mounted in the drive link 2, an actuator 4 which couples to the drive link 2 and the drive plate 3, a ratchet drive 5 and a reaction arm 8.

The drive link 2 is machined from a single billet of aluminium. Not only is this an expensive manufacturing process, but the resulting drive link 2 and drive plate 3 present pinch points where an operator could trap a part of the body, such as a finger or skin for example.

The pinch points are the encircled areas indicated by the letter P in Figures 1b and 1c. The billet is machined so that the drive plate 3 may be inserted into position as shown in Figure 1c, where the piston 6 of the actuator 4 is connected to a pin 7 of the drive plate. As is best appreciated from Figure 1b, the drive plate 3 sits between two spaced apart bosses 2a, 2b of the

drive link 2. Flat edges 2c, 2d extend between the two bosses 2a, 2b. The potential pinch points P are located respectively in the regions bounded by the flat edges 2c, 2d, the inner surfaces of the bosses 2a, 2b and the outer surface of the drive plate 3. In use, the drive plate 3 rotates back and forth to operate the ratchet mechanism 5 and any tool attached thereto. The forces exerted by the actuator 4 can be very great. A finger located in one of the regions P could become trapped very easily as the drive plate rotates under the action of the actuator 4 and finger could be crushed between the outer surface of the drive plate 3 and one of the flat surfaces 2c, 2d.

It would therefore be desirable to provide a drive link 2 which is not only less costly to manufacture, but which reduces the possibility of parts of the body becoming trapped in the tool.

Detailed Description of the Preferred Embodiment

Figures 2a and 2b illustrate an assembled hydraulic torque wrench of the invention.

Instead of the drive link 20 being machined from a single billet of aluminium it is formed by two parts which interlock, referred to hereafter as link halves. Each link half 20a, 20b is manufactured from a casting, for example of steel or aluminium. As can be seen from Figure 2a and 2b, a complete enclosure is formed around the drive plate 3, eliminating the pinch points P of the prior art device.

Figures 3a and 3b illustrate the two link halves 20a, 20b. Each half comprises a side plate 21 a, 21 b and extending perpendicularly therefrom respective perimeter walls 22a, 22b. The perimeter walls 22a, 22b each comprise interlocking elements. When the two link halves are fastened together the interlocking elements resist relative rotation between the two link halves 20a, 20b. As can be seen from Figure 3a, the link half 20b includes key elements 22c, 22d extending from the perimeter wall 22b away from the side plate 21b. Figure 3b illustrates the inside of the link half 20a. It can be seen that the wall 22a includes recesses 22e, 22f, each positioned to receive a respective one of the key elements 22c, 22d.

Referring now to Figures 4a to 4c, the assembled hydraulic torque wrench comprises the link drive 20 which includes a drive plate 3, a ratchet drive mechanism 5, an actuator 4 coupled to the link drive and the drive plate, a reaction arm 8 and drive head 30 to which a socket may be attached for example. The link halves 20a, 20 each include slots 26a, 26b which align and receive a pin 4’ of the actuator 4. The actuator includes a hole 4” which aligns with holes 28a, 28b of the respective link halves 20a, 20b to receive a pin 27 which secures the actuator to the link drive.

The piston 6 of the actuator 4 attaches to the drive pin 7 of the drive plate 3 so that recuperating motion of the piston 6 translates into rotational motion of the drive plate 3.

The two link halves 20a, 20b are secured together by fasteners in the form of bolts 25 which pass through holes 24 in the link half 20b and engage with internally threaded and aligned holes 23 in the link half 20a. The combination of the interlocking elements (the key elements 22c, 22d and recesses 22e, 22f) resisting relative rotation between the two link halves and the bolts 25 engaged with internally threaded holes 23 preventing lateral separation of the two link halves ensures that torque reacted through the drive link does not cause the link halves to separate.

In the illustrated examples the keys 22c, 22d are integral with link half 20b. In an alternative structure each link half may comprise a recess or recesses and a separate key may be seated in aligned recesses. With the link halves held together agains movement away from each other, for example by the fasteners described above, the combination of separate keys sitting in aligned recesses would resist rotational forces acting to cause relative rotation between the two link halves.

It is also possible that the link drive may be formed by more than two interlocking parts. For example, one or spacers having the same perimeter shape as the walls 22a, 22b could be located between the link halves 20a, 20b. Further, where the link is formed by two interlocking parts those parts may not be halves of the link in strict terms. For example, the walls 22a, 22b may not be of equal width.

Claims

1. A torque wrench drive link comprising a housing, a drive plate mounted for rotation in the housing and an actuator coupling, the actuator coupling providing for attachment of an actuator to the housing, wherein the housing comprises at least two interlocking parts, each interlocking part including an internally splined opening for mounting a reaction arm, and wherein the at least two interlocking parts of housing provide a shroud which encloses the drive plate in the housing and prevents access to the drive plate when the torque wrench drive link is coupled to the actuator.

2. A torque wrench drive link according to Claim 1, wherein one interlocking part includes at least one protrusion and another other interlocking part includes at least one recess, the at least one protrusion and at least one recess so shaped and dimension as to engage with one another and prevent relative rotation between the interlocking parts.

3. A torque wrench drive link according to Claim 1, wherein each interlocking part include at least one recess and a key is located in the aligned recesses of adjacent interlocking parts.

4. A torque wrench drive link according to any preceding claim, wherein the at least two interlocking parts secured together by a plurality of fasteners.

5. A torque wrench drive link according to Claim 4, wherein each of the fasteners includes an externally threaded bolt or screw.

6. A torque wrench drive link according to Claim 5, wherein one of the interlocking parts includes a plurality of through holes, and another of the interlocking parts includes a corresponding plurality of internally threaded holes which align with the through holes, the fastener passing through one of the through hole engages with internal threads of the aligned hole.

7. A torque wrench comprising a torque wrench drive link according to any of Claims 1 to 6, an actuator in driving connection with the drive plate, a ratchet drive mounted within the drive plate, a reaction arm and means for mounting the reaction arm to the internally splined opening of at least one of the interlocking parts.

8. A torque wrench according to Claim 7, wherein the means for mounting the reaction arm to the internally splined opening of at least one of the interlocking parts includes an externally splined hollow shaft.

9. A torque wrench according to Claim 7 or 8, further comprising a socket attachable to a socket connector, the socket connector in driving connection with the ratchet drive.