Chain assembly/disassembly

Abstract

 A tool (20) is adapted to remove and insert link pins from and into joints connecting adjacent links of a chain. The chain components are positioned at an operative region (26) at which they are supported against plastics deformation whilst a punch (34) mounted on a movable carrier (36) is used to remove or insert a link pin.
An angling post (54) induces an angle between the chain components such that the free outer link plate at a joint is preferably supported against plastic deformation by contact with its adjacent inner link plate. A retention member (60) helps to retain the chain components at the operative region (26) . An orientation post, receivable between the outer link plates at a joint, ensures that the joint can only be positioned at the operative region (26) in one orientation and the width of the jaw of the operative region (26) ensures that a joint can only be positioned at one site. A storage recess (68) with a removable cap (70) may be used to retain a spare link pin or rivet for a chain.
To be accompanied when published by Figure 2 of the drawings.

Description

[0001] This invention relates to the assembly and disassembly of chains, particularly, though not exclusively, roller chains. More particularly, this invention relates to the extraction or insertion of a coupling, link pin or rivet used to secure together adjacent links of a chain.

[0002] Tools for inserting or extracting chain rivets have been known for some time and one example of such a tool is described in British Patent No. 912 703. In order to extract a rivet from a chain using this tool a joint of the chain is located in the jaw of the tool and the rivet to be extracted is aligned with an advancible punch which may be used to push the rivet through and out of the link. Insertion of a rivet follows a similar procedure except that the links are introduced to a different anvil, the punch being used to push the rivet into a link.

[0003] When a chain is in use it is important that adjacent links can rotate freely about a joint. To provide for this movement, chain links are typically constructed such that there is a clearance gap between the outer link plates and the inner link plates of the respective links at each joint. One of the disadvantages of the aforementioned tool is that both during extraction and insertion of a rivet the inner and outer link plates at a joint are forced together as the rivet is forced through the respective link plates. Consequently, when adjacent links are disassembled or assembled using this tool the resulting joint is often too stiff to function properly, the outer link plates having been deformed inwards to lie against, and in some cases, to grip the inner link plates. This problem is currently alleviated by using the aforementioned tool in a different mode to deform the outer link plates to re-introduce a clearance gap.

[0004] Prior art tools have suffered from a disadvantage of initially deforming the links of a chain and of subsequently requiring a separate operation to reintroduce a clearance gap into a deformed link to permit the chain to function correctly. In addition, in some tools it is easy to mis-position a chain within the tool and consequently to risk damaging the chain, the tool, or both when attempting to extract or insert a rivet.

[0005] It is an aim of the present invention to provide an improved method of, and tool for, extracting or inserting a rivet or link pin from or into a joint of a chain.

[0006] According to a first aspect of the invention, there is provided a tool adapted to extract and/or insert a coupling from or into a joint connecting first and second chain components, the tool comprising drive means adapted to displace the coupling and the chain components relative to each other, and support means adapted to position the first and second chain components at an operative region of the tool such that when the coupling is being driven from, through, or into the joint each link plate at that joint is supported against plastic deformation.

[0007] In a preferred embodiment the tool comprises a jaw in which a joint may be positioned and the drive means may move relative to the jaw to push a rivet into or from a joint held therein. The drive means may comprise a punch mounted upon a carrier. The carrier may be an externally screw-threaded shaft which is rotatable within a correspondingly threaded bore of the tool. A trapizoidal type thread may be used for the drive means for the advantageous force transfer characteristics this provides as a power thread.

[0008] The tool may also be provided with position means adapted to position a joint of a chain in the tool such the the rivet or at least the bore of the joint through which the rivet passes is axially aligned with the axis along which the drive means is movable. Where a tool is adapted for use with a roller chain the position means may comprise a saddle or equivalent roller locating means which may have an axially extending U-shaped recess adapted to receive a roller of a joint and hence to position the joint relative to the tool and to the drive means.

[0009] Orientation means may also be provided and may be adapted to permit a joint to be positioned in only one orientation at the operative region of the tool. Where, for example, a tool is adapted for use with a roller chain the orientation means may comprise a member, such as an orientation post, adapted to co-operate with the inner and/or outer link plates (for example adapted to be received between the outer link plates of a joint positioned in the tool). The orientation means may be of such cross-section that it may be received between the outer link plates of the joint but cannot fit between the inner link plates of a joint. In this way a joint must always be positioned within the tool with its outer link plates co-operating with the orientation means.

[0010] The support means may comprise a rear anvil adapted to support directly the external surface of an outer link plate of a joint placed in the tool. The support means may comprise a pair of rear anvils each rear anvil being separated by a slot, preferably an axially extending U-shaped slot. In this case, each rear anvil is adapted to support the external surface of an adjacent outer link plate on an opposed side of the coupling receiving bore of the outer link plate. The U-shaped slot may be adapted to receive a coupling which is pushed out cf the joint through the outer link plate. It will be appreciated that although only one support for the outer link plate may be necessary the provision of a pair of rear anvils to provide support on each side of the coupling receiving bore of the link plate provides greater support for the link plate against deformation.

[0011] In some chain constructions ( for example, in Hyperglide (TM) chains) the outer link plates are convex in shape rather than planar. To accommodate this construction one or each of the rear anvils may be provided with a rear anvil recess which extends axially towards the anvil to provide an axial anvil projection adapted to provide the point of contact between that anvil and the adjacent link plate.

[0012] The support means may be adapted to directly support each link plate of a joint. Alternatively or additionally, the support means may position the chain components such that each link plate is supported. One link plate may support another via their contact.

[0013] It will be appreciated that the aim of one embodiment of this invention is to prevent plastic deformation of the link plates of a joint when a rivet is forced into, through, or out of a joint. Consequently, it is not necessary that each link plate be supported to prevent any possible axial movement but merely that each link plate be sufficiently supported so that no permanent plastic deformation occurs during the rivet inserting or extracting process. Elastic deformation may be permissible. Similarly, the link plates need not be supported when at rest but need only to supported when a coupling is being driven into, from, or through a joint.

[0014] Where the tool comprises orientation means received between the outer links of a joint such orientation means may also provide a support member forming part of the support means and being adapted to support directly the inner surface of the outer link plate opposite the drive means.

[0015] In one preferred arrangement the support means is adapted to directly support the outer surface of an outer link plate positioned opposite the drive means and to position the first and second chain components at a relative angle so that the outer surface of each inner link plate contacts the inner surface of its adjacent outer link plate. Additional support means may be provided to support directly any of the link plates.

[0016] In some chain constructions, for example roller chain constructions, the inner link plates at a joint are held in spaced apart relations. In a roller chain construction the inner link plates at a joint are kept apart by bushes upon which the roller rotates. Consequently, where a tool is adapted for use with roller chains it is not always necessary to provide support means to support the inner link plates at a joint. In this case, when the first and second chain components are positioned within the tool at a relative angle the rear outer link plate may be supported against axial movement of the rivet by the rear anvil and the front outer link plate may be supported by its adjacent inner link plate.

[0017] The first and second components may be positioned at a relative angle by an angling formation. The angling formation may project axially from the rear anvil and be adapted to deflect an inner link plate of a joint relative to the anvil and consequently to introduce an angle between the first and second chain components.

[0018] According to a second aspect of the invention there is provided a tool adapted to extract or insert a coupling from or into a joint connecting first and second chain components, the tool comprising drive means adapted to displace the coupling and the chain components relative to each other and angling means adapted to position the first and second chain components at an angle relative to each other at an operative region of the tool when the tool is in use.

[0019] This helps to ensure that there is some axial play in the joint in use of the chain after the coupling has been introduced to couple the two components.

[0020] The relative angle between the first and second chain components may be induced when the joint of a chain is introduced into the tool or the angle may only be induced by engaging the drive means with the rivet of the joint.

[0021] In the case of a roller chain the support means preferably induce a sufficient relative angle between the inner and outer link plates such that there is a point of contact providing a point of support between each inner link plate and its adjacent outer link plate at a joint.

[0022] According to a third aspect of the invention there is provided a tool adapted to insert or extract a coupling into or from a joint connecting first and second chain components, the tool comprising drive means adapted to displace the coupling and the chain components relative to each other, support means adapted to support the components against the axial displacement of the coupling and orientation means adapted to allow the first and second components to be positioned in only one orientation relative to the support means at an operative region of the tool.

[0023] According to a fourth aspect of the invention there is provided a tool adapted to insert or extract a coupling into or from a joint connecting first and second chain components, the tool comprising drive means adapted to axially displace the coupling and the chain components relative to each other, support means adapted to support the components against axial displacement of the coupling and the tool having only one site at which the joint may be positioned within the tool.

[0024] Preferably the tool comprises a jaw within which the joint of a chain is positioned and the width of the jaw is such that the joint may only be introduced into the jaw at one site. This alleviates the problem that exists with prior art tools comprising more than one site within the tool at which the joint can be located. When only one site is provided it is not possible to position the joint at an incorrect site within the tool.

[0025] According to a further aspect of the invention there is provided a tool adapted to insert or extract a coupling into or from a joint connecting first and second chain components, the tool having an operative region at which are provided drive means adapted to displace the coupling and the chain components relative to each other, support means adapted to support the components during use of the tool, and retention means adapted to prevent the chain components from accidentally leaving the operative region.

[0026] The retention means is preferably movable relative to the operative region.

[0027] The retention means may comprise a member mounted on the body of the tool, and adapted to be held manually against the chain components positioned in the tool. Preferably the retention means applies pressure in use to the chain components. The retention means may also assist in correctly aligning a joint within the tool.

[0028] According to a yet further aspect of the invention there is provided a tool adapted to extract or insert a coupling from or into a joint of a chain, the tool comprising a handle adapted to be held in the hand of an operator when the tool is in use.

[0029] The handle may also be adapted to be held in a vice or clamp when the tool is in use.

[0030] According to another aspect of the invention there is provided a tool adapted to extract or insert a coupling from or into a joint connecting first or second chain components the tool comprising storage means adapted to store a coupling which may be inserted in to the chain.

[0031] The storage means may comprise a hole provided in the body of the tool into which a coupling can be inserted. The hole may be closed by a removable cap to prevent a stored coupling from falling out accidentally. Couplings for use with a coupling inserting tool are easily lost or misplaced and it is convenient to provide storage mean associated with the tool.

[0032] According to a further aspect of the invention there is provided a tool adapted to extract or insert a coupling from or into a joint connecting first and second chain components, the tool comprising drive means adapted to axially displace the coupling and the chain components relative to each other, support means adapted to support the chain components against axial displacement of the coupling, and indicating means adapted to indicate a position of the drive means relative to the tool.

[0033] Preferably the indicating means provide a visual marker which indicates the position of the tip of the punch relative to the tool.

[0034] When extracting a coupling (or pin) from a joint it is preferable that the pin is not pushed entirely through and out of the joint but is retained with one of its ends held in the rear outer link plate. In this way the chain components can be separated and when an operator attempts to join the outer link plates to the inner link plates of another joint he or she can use the rivet which is still held in the outer link plate and which is already correctly aligned with the bore through which the rivet is to pass. Preferably the indicating means comprises a first visual marker provided on and moving with the drive means and a second stationary visual marker provided on the tool body. Alignment of the first and second markers may indicate that the punch has been advanced to a sufficient position to permit the release of the joint whilst retaining the rivet in the outer link plate.

[0035] According to another aspect of the invention there is provided a tool adapted to extract and/or insert a coupling from or into a joint connecting first and second chain components, the tool comprising drive means adapted to displace the coupling and the chain components relative to each other, support means adapted to support the chain components against displacement of the coupling and stop means, associated with the drive means, adapted to limit the distance by which the drive means may be advanced with respect to the support means.

[0036] The stop means are adapted to prevent a user advancing the punch too far when pushing a coupling out of a chain joint and accidentally pushing the coupling entirely out of the join as opposed to leaving one end of the coupling retained in the rear outer link plate. Where the drive means comprises a punch mounted on a screw threaded carrier, the stop means may be provided by a stop member which cooperates with the screw threaded carrier to prevent the carrier advancing beyond the stop member. The stop means may be formed as an integral part of the housing in which the screw threaded carrier is rotated to advance the punch.

[0037] It will be understood that an embodiment of the present invention may comprise features of any aspect of the invention.

[0038] According to a yet further aspect of the invention there is provided a method of extracting or inserting a coupling from or into a joint connecting first and second chain components, the method comprising supporting each of the first and second chain components against plastic deformation and displacing the coupling axially relative to the components to extract it from or insert it into the joint.

[0039] According to another aspect of the invention there is provided a method of extracting or inserting a coupling from or into a joint connecting first and second chain components, the method comprising inducing a relative angle between the first and second components and displacing the coupling axially relative to the components to extract it from or insert it into the joint.

[0040] It will be appreciated that we see methods of using a tool/holding a chain for extraction of a coupling as being further aspects of the invention.

[0041] In order that the invention may be more clearly understood embodiments of the invention will now be described, by way of example only, with reference to the accompanying drawings in which:

Figure 1a shows a perspective view of one form of chain with which the invention is adapted to be used;

Figure 1b shows a perspective view of a Hyperglide (TM) type of chain having convex outer link plates;

Figure 1c Shows a perspective view of a Seddis (TM) type of chain having concave inner link plates;

Figure 2 shows a side view of a tool embodying several aspects of the invention;

Figure 3 shows a side view of the tool of Figure 2 in a different configuration;

Figure 4 shows a sectional view along the line 44' of Figure 3;

Figure 5 shows a plan view of the tool in the configuration of Figure 3;

Figure 6 shows an enlarged portion of part of the tool (the jaw) shown in Figure 5; and

Figure 7 shows a plan view of first and second chain components positioned in the jaw of the tool.

[0042] Figures 1a, 1b, and 1c illustrate lengths of roller chain 2 comprising first and second chain components 4, 6, each chain components comprising a pair of opposed link plates 8. Adjacent first and second chain components are connected by a coupling in the form of a pin or rivet 16 passing through a joint 10, of the chain. Four link plates 8 are coupled together by the rivet 16 at the joint 10 the inner two link plates being separated by a bush 12 over which is located a freely rotatable roller 14.

[0043] The joint 10 is provided with a clearance gap (not shown) between the inner and outer link plates to allow the first and second chain components 4, 6 to rotate freely about the axis of their linking rivet 16.

[0044] Referring now to figures 2-7 a tool 20 for inserting or extracting a coupling comprising a rivet 16 into or from a joint 10 of a chain 2 has a body 22 comprising a handle 24 and an operative region in the form of a jaw 26 adapted to receive a joint 10 of a chain 2 from or into which a rivet 16 is to be extracted or inserted. The handle 24 is provided with a palm engaging side 28 and finger grip formations 30 on an opposed side; it is adapted to be gripped in the hand of an operator the finger grip formations 30 facilitating the holding of the tool in the hand. Alternatively, the handle 24 may be secured in the jaws of a vice or clamp.

[0045] The tool 20 also has drive means positioned at the front of the tool and comprising a punch 34 mounted upon a carrier comprising an externally screw-threaded shaft 36 which is rotatable within a correspondingly threaded bore 38 provided in the body 22 of the tool 20. The punch 34 is adapted to connect with a rivet 16 of a joint 10 positioned in the jaw 26 of the tool and to drive the rivet through the joint. The punch 34 is advanced or retracted relative to the jaw by rotating the screw threaded shaft 36 which is provided with a drive hand 40. The drive handle 40 facilitates manual rotation of the drive means and also provides a mechanical advantage to increase the force provided by the operator which is transmitted to the punch 34 by the drive means to displace the rivet 16 of a joint 10.

[0046] The tool also has support means comprising a pair of rear anvils 44, 46 (shown in figures 4 and 5) separated by a U-shaped slot 48. Each rear anvil 44, 46 is adapted to directly support the external surface of an adjacent outer link plate of a joint 10 positioned in the jaw 26 of the tool 20. The rear anvils 44, 46 support this outer link plate on either side of the bore of the link plate in which the rivet 16 is received when the joint 10 is assembled. When a rivet 16 is pushed through and out of the joint by the punch 34 it is received in the U-shaped slot 48. Preferably, when a rivet 16 is pushed through a joint to release the first chain component 4 from the second chain component 6, the rivet 16 is not pushed entirely through the joint but is pushed sufficiently to release the first and second components but with one of its ends still retained within the rear outer link plate; this is described below in more detail and facilitates the reinsertion of a rivet 16 into a joint 10. When the rivet 16 is held in this way with one of its ends held in the bore of the rear anvil link plate, the free end of the rivet projects into the U-shaped slot 48 between the pair of rear anvils 44, 46.

[0047] In order that the tool can accommodate not only chains having planar or concave link plates 8, but also chains having convex outer link plates, the rear anvil 44 which is adapted to lie opposite the outer link plate at a joint is provided with a rear anvil recess 50 and a rear anvil projection 52, as illustrated in Figures 6 and 7. In use, one rear anvil 46 supports the end of the rear outer link plate 81 of a joint positioned in the tool and the rear anvil projection 52 of the other rear anvil 44 supports a portion of that rear link plate on an opposed side of the bore through which the rivet 16 passes. Any convex curve of an outer link plate (not shown) is accommodated by the rear anvil recess 50 so that the longitudinal axis (referenced 100) of the second chain component 6 lies parallel to the ends of the U-shaped slot 48 emerging into the jaw 26 of the tool 20 and the free end of that outer plate is not pivoted away from its respective rear anvil 46 by a convex outer link plate having two points of contact with the other rear anvil 44.

[0048] The support means also comprise an angling formation in the form of an angling post 54. In use, the angling post 54 contacts the rear inner link plate 83 of a joint 10 positioned in the tool and positions the first chain component 4 at a respective angle to the second chain component 6 so that its longitudinal axis (referenced 101) is not parallel to the longitudinal axis 100 of chain component 6.

[0049] In some roller chain constructions the inner link plates 83, 84 at a joint are not planar but are partially concave about their respective longitudinal axis (for example Seddis (TM) chains) . In order to accommodate this type of chain construction (shown in figure 1c) the angling post 54 comprises a post of radial cross section which projects axially from the rear anvil 46 and is adapted to be opposite the rear inner link plate 83 of a joint 10 positioned in the jaw 26 of the tool. The post 54 is adapted to contact the central portion of the outer surface of the inner link plate 83. This formation of angling post can thus accommodate chain formations having planar or concave inner link plates.

[0050] The support means also comprise a support member in the form of an inter-plate post 56 which projects laterally from the base of the jaw 26. The inter-plate post 56 may be of circular or of square or of any other suitably shaped cross section. The inter-plate post 56 is adapted to be received between the opposed outer link plates 81, 82 of a joint 10 positioned in the tool and to provide an additional support for the front outer link plate 82 against plastic deformation when the tool is in use.

[0051] The inter-plate post 56 also provides orientation means which permit a joint 10 to be positioned in only one orientation within the tool. The width of the inter-plate post is less than the distance separating the opposed outer link plates 81, 82 at a joint 10 but is greater than the distance separating the opposed inner link plates 83, 84 at a joint. The inter-plate post can therefore only be received between the opposed outer link plates of a joint 10 positioned in the tool and consequently the joint 10 can only be positioned in the jaw 26 of the tool in this orientation (in fact it will be appreciated that the chain an also be put in upside down, but that the first and second components will have the same effective configuration).

[0052] The support means positions the first and second components 4 , 6 of a chain at a relative angle within the jaw 26 of the tool (as shown in figure 7). When the drive means is engaged with the joint 10 to displace the rivet 16 the joint 10 is forced against the rear anvils 44, 46 and the second chain components 6 is forced into alignment with the rear anvils 44, 46. The first chain component is held away from the rear anvil 46 by the contact of the angling post 54 with the rear inner link plate 83. This induces a relative angle between the first and second chain components 4, 6. The angling post 54 is positioned and dimensioned such that when the relative angle is induced between the first and second components the free end of the rear inner link plate 83 contacts the inner surface of the rear outer link plate 81 and the free end of the front outer link plate 82 contacts the outer surface of front inner link plate 84. The inner link plates 83, 84 are held apart by an internal pair of bushes 12 and each link plate of the joint 10 is thus supported against plastic deformation; the rear outer link plate 81 is supported by the rear anvils 44, 46; the inner link plates 83, 84 are supported by the pair of bushes 12 and the front outer link plate 82 is supported firstly by its contact with the front inner link plate 84 which is in turn supported through the pair of bushes by the rear inner link plate 83 acting against the rear outer link plate 81 and the angling post 54, and additionally by the inter-plate post 56.

[0053] The tool 20 is also provided with position means comprising a saddle 58 arranged to facilitate positioning of the joint having the rivet 16 (or that is to receive the rivet 16 when a rivet is being reintroduced to join the two chain components) so that the rivet is aligned with the punch 34 and with the U-shaped slot 48 provided between the pair of rear anvils 44, 46.

[0054] The inter-plate post 56 also comprises a part of the position means and co-operates with the joint 10 to position this within the jaw 26. In the illustrated embodiment the inter-plate post 56 facilitates the positioning of the front outer link plate 82 in the jaw 26 and the positioning of the roller 14 and hence the first chain component 4) in the saddle 58. The inter-plate post 56 may be of square or of any other suitably shaped cross section adapted to position any desired part of the joint 10 relative to the tool.

[0055] The distance between the inter-plate post 56 and the front and rear of the jaw 26 is not sufficiently large to allow a first or second chain component 4, 6 to be inserted between the inter-plate post 56 and the front or rear surface of the jaw 26. Consequently, a joint 10 can only be positioned in the jaw 26 with the opposed outer link plates 81, 82 of a joint 26 surrounding the inter-plate post 56. There is thus only one site within the jaw at which a joint 10 can be positioned and this reduces the risk of an operator mis-positioning a joint 10 within the jaw 26.

[0056] The front surface of the jaw 26 is provided with a central insert rivet slot 42. When a rivet 16 is to be inserted into a joint 10, the rivet 16 initially projects from the front outer link plate 82 of one of the two components to be joined and is received in the insert rivet slot 42.

[0057] Retention means comprising a retention member 60 pivotally mounted on the tool 20 is also provided. The retention member comprises a pressure plate 62 mounted upon a thumb plate 66. When a joint 10 is to be positioned in the jaw 26 of the tool 20 the thumb plate 66 is raised (as shown in Figure 3) to allow free access to the jaw 26. When a rivet 16 is then to be extracted or inserted, the retention member 60 is lowered (as shown in Figure 2) and held by the operator against the tool 20, the operator's thumb of the hand in which the tool is being held acting against the thumb plate 66 so that the pressure plate 62 acts against the joint positioned in the tool to bias the joint against the base of the jaw 26 and the roller 14 against the saddle. The retention means in this embodiment also assists in ensuring that the chain is in a proper position before the drive means is operated, and in ensuring that there is only one way in which the chain can be positioned. In use, a part circular profile 91 of the pressure plate acts against the top of the roller 14 of a joint positioned in the tool. This biases the roller 14 (and consequently the rivet passing through the roller) into alignment with the line of the punch 34 so that the joint is encouraged into the correct position for correct operation of the tool. The roller 14 is thus held to one side by contact with the part circular profile 91 of the pressure plate and on the other side by contact with the inter-plate post 56. The retention means, in association with the profile of the jaw 26, also helps to prevent the chain components accidentally slipping out of the operative region 26 of the tool; a flat profile 92 of the retention means acts against the top of the link plates positioned in the tool to assist in this.

[0058] Storage means comprising a storage hole 68 is provided in the body 22 of the tool 20. The storage hole 68 is adapted to store and retain a rivet (not shown) which can be inserted into a joint 10. The storage hole 68 is closed by a removable storage cap 70 which prevents a stored rivet from falling out accidentally.

[0059] The tool 20 is also provided with a stop member 72 formed as an integral part of the housing in which the screw threaded carrier 36 is rotated to advance the punch 34. The stop member 72 provides a barrier beyond which the screw threaded carrier cannot be advanced; in this way, it limits forward movement of the punch 34 into the jaw 26 of the tool and is arranged in combination with the punch and the carrier so that the punch cannot be advanced into the jaw further than a position at which a rivet being extracted from a joint is pushed sufficiently far to release the components of the joint but the rivet is still held at one end in the rear outer link plate 81.

[0060] When a rivet 16 is to be extracted from a joint 10 an operator grips the tool 20 in one hand placing his or her fingers around the finger grip formations 30 of the handle 24 and gripping the palm engaging side 28 of the handle 24 in his or her hand. The operator then uses his or her free hand to accomplish the following steps. The punch 34 is sufficiently retracted from the jaw 26 by rotating the screw threaded shaft 36 with the aid of the drive handle 40. The retention member 60 is raised to provide access to the jaw 26 and a joint of a chain is positioned in the tool. As previously described, it is only possible to place the chain at one site and in one orientation within the jaw 26 of the tool 20, the inter-plate post 56 being received between the opposed outer link plates 81, 82 of a second component 6 and the roller 4 resting on the saddle 58. The saddle 58 and the inter-plate post 56 position the joint 10 such that the rivet 16 is axially aligned with the punch 34 and with the U-shaped slot separating the rear anvils 44, 46.

[0061] The retention member 60 is then lowered so that it lies across the top of the jaw 26 and it held in this position by the operator using his or her thumb of his or her hand gripping the tool handle 24 against the thumb plate 66; the pressure plate 62 biases the chain components 4, 6 against the base of the jaw 26.

[0062] The operator now advances the punch 34 into the jaw 26 by rotating the screw threaded shaft 36. When the punch connects with the rivet 16 of the joint 10, the second chain component 6 is pushed rearwards such that its rear outer link plate 81 is held against and is supported by the rear anvils 44, 46. The rear inner link plate 83 of the first chain component 4 is held away from the rear anvil 46 and is supported at one point by angling post 54. This induces an angle between the first and second chain components 4, 6 causing the front outer link plate 82 to be supported by the first chain component 4, as previously described. The front outer link plate 82 is also supported by the inter-plate post 54.

[0063] The operator advances the punch 34 until further advancement is prevented by contact of the punch carrier 36 with the front of its housing which provides the stop 72. When the punch 34 is advanced to this position the rivet 16 will still be held with one of its ends in the rear outer link plate 81, its other end projecting into the U-shaped slot 48 separating the rear anvils 44, 46, but the rivet 16 will have been pushed sufficiently out of the joint 10 to release the first chain component 4 from the second chain component 6.

[0064] The operator now retracts the punch 34 from the jaw 24, raises the pressure member 60 and withdraws the now uncoupled first and second chain components 4, 6, from the jaw 26.

[0065] When a first chain component 4 is to be joined to a second chain component 6, a similar procedure is followed. The tool is gripped as before and the punch 34 is sufficiently withdrawn to allow the components to be inserted into the jaw 26. A rivet 16 is preferably already held with one of its ends in the front outer link plate 82 of the second component 6; the second component is positioned in the jaw 26 and the rivet 16 projecting from the second component is received in the insert rivet slot 42. Once the first component 4 has also been positioned in the jaw 26, the roller 14 being received on the saddle 58, the pressure member 60 is lowered and held in place and the punch 34 is advanced to push the rivet 16 through the joint 10 to connect the first and second components 4, 6. During the insertion of a rivet 16 the link plates of the first and second components 4, 6 are supported as before.

Claims

1. A tool (20) adapted to extract and/or insert a coupling (16) from or into a joint (10) connecting first and second chain components (4, 6), the tool (20) comprising drive means (34, 36) adapted to displace the coupling and the chain components relative to each other and characterised in that support means (44, 46, 54) is adapted to position the first and second chain components (4, 6) at an operative region (26) of the tool such that when the coupling (16) is being driven from through or into the joint (10), each chain component (4, 6) at that joint is supported against plastic deformation.

2. A tool (20) adapted to extract and/or insert a coupling (16) from or into a joint (10) connecting first and second chain components (4, 6), the tool (20) comprising drive means (34, 36) adapted to displace the coupling and the chain components relative to each other and characterised in that angling means (54) are adapted to position the first and second chain components (4, 6) at a relative angle to each other at an operative region (26) of the tool when the tool is in use.

3. A tool (20) in accordance with Claim 1, characterised in that angling means (54) are adapted to position the first and second chain components (4, 6), at a relative angle to each other at the operative region (26) of the tool when the tool is in use.

4. A tool (20) in accordance with any proceeding claim, characterised in that, in use, one of the outer link plates (82) at the joint (10) is directly supported against movement of the coupling (16) by one of the inner link plates (84).

5. A tool (20) in accordance with any preceding claim, characterised in that orientation means (56) is adapted to permit a joint (10) to be positioned in only one orientation at the operative region (26) of the tool, the orientation means comprising an orientation post (56) receivable between the outer link plates (81,82) of the joint (10) when positioned at the operative region (26) but not receivable between the inner link plates (83,84) at the joint (10).

6. A tool (20) in accordance with any preceding claim, in which the support means comprises a pair of rear anvils (44, 46) and characterised in that at least one of the rear anvils (44) is provided with an axial angle projection (52) adapted to provide a point of contact, in use, between that anvil and the adjacent link plate (81) of the joint (10) positioned in the tool.

7. A tool (20) in accordance with any preceding claim in which the operative region of the tool comprises a jaw (26) within which the joint (10) is positioned in use and characterised in that the width of the jaw (26) is such that the joint (10) may only be introduced into the jaw (26) at one site.

8. A tool (20) in accordance with any preceding claim, characterised in that retention means (60) is adapted to prevent the chain components (4, 6) from accidentally leaving the operation region (26) in use, the retention means comprising a member (60) movably mounted on the body of the tool and adapted to be held against the chain components (4, 6) positioned in the tool for use.

9. A tool (20) in accordance with any preceding claim, characterised in that stop means is associated with the drive means (34, 36), the stop means being adapted to limit the distance the drive means may be advanced with respect to the operative region (26).

10. A tool (20) in accordance with any preceding claim, characterised in that the tool comprises storage means (68, 70) adapted to retain a coupling which may be inserted into a chain.

Drawing