TOOLS

FIELD OF INVENTION

[0001 ] The present invention relates to the field of hand operated tools. It will be convenient to hereinafter describe the invention with particular reference to hand tools such as scissors, tin snips, clamps and blind rivet setting tools, but it should be appreciated that the present invention is not solely limited to such tools.

BACKGROUND ART

[0002] Blind rivets (sometimes referred to as pop-rivets) are known in the art and generally consist of a headed mandrel of specified diameter and length, on which is carried a deformable or expandable sleeve (also referred to as a shank) of a size which can be received through holes provided in two sheets of material to be joined. The sleeve has a flange (also referred to as a rivet head) at one end thereof, which cannot pass through the holes, but bears against the innermost sheet when the mandrel head and sleeve have been passed through the holes. With the blind rivet held in position by the nose piece of an appropriate tool, the mandrel is gripped and force is applied thereto to pull the headed portion of the mandrel into deforming relationship to the sleeve and thereby clamp or rivet the two sheets of material together between the deformed sleeve (bearing against the outermost sheet) and flange (bearing against the innermost sheet) . As the mandrel head tightens on the outermost sheet, the applied force on the mandrel becomes so great that it fractures (often along a break notch provided in the mandrel), leaving the headed portion within the hole and permitting the remainder of the mandrel to be discarded.

[0003] The tools used for setting blind rivets comprise generally a nose piece in which the rivet can be mounted for application, a gripping means, usually in the form of spring loaded collet jaws for embracing the mandrel and coupling it to a pulling force, and means for applying the pulling force to cause deformation of the sleeve and subsequent fracture of the mandrel. In high production assembly lines and the like, the force may be applied through power means, electrically operated, hydraulic or pneumatic, for example. In field work, maintenance work, and for low volume applications such as handy-man jobs, however, the force is generally manually applied through a mechanical linkage which is provided by a pivoted lever forming part of the manually operated tool. The pulling force required to be applied to the mandrel varies depending on the size, type and material of the rivet and can sometimes be in excess of the hand force that can be exerted by an individual. Such hand tools, therefore, are often designed with elongated handles, for example, so that sufficient force can be applied by hand to set the rivet and fracture the mandrel, regardless of the size, type and material of the rivet. Such hand tools, however, can be unwieldy and difficult to operate.

[0004] As would be appreciated, similar issues can also be encountered during use of other hand operated clamping, cutting and fastening tools, such as scissors and clamps, for example.

[0005] It is to be appreciated that any discussion of documents, devices, acts or knowledge in this specification is included to explain the context of the present invention. Further, the discussion throughout this specification comes about due to the realisation of the inventor and/or the identification of certain related art problems by the inventor. Moreover, any discussion of material such as documents, devices, acts or knowledge in this specification is included to explain the context of the invention in terms of the inventor's knowledge and experience and, accordingly, any such discussion should not be taken as an admission that any of the material forms part of the prior art base or the common general knowledge in the relevant art in Australia, or elsewhere, on or before the priority date of the disclosure and claims herein.

SUMMARY OF INVENTION

[0006] In accordance with a first aspect of the present invention, there is provided a tool operable through a hand squeezing force applied, in use of the tool, by an operator between handgrips of first and second handle members. The tool includes a first application member supported on the first handle member, a second application member supported for reciprocal displacement relative to the first application member, and a linkage mechanism coupling the second handle member to the second application member. The linkage mechanism includes a user selectable means for adjusting the mechanical advantage of force, in use, transferred from the handgrips to the application members. [0007] The tool of the present invention advantageously has a user selectable means for adjusting the mechanical advantage of force, in use, transferred from the handgrips to the application members. Thus, a user is able to select a degree of mechanical advantage provided by the tool, depending on the specific job to be performed . If it is necessary to apply a greater force, a user can simply actuate the user selectable means, instead of possibly having to select a different tool. Furthermore, given its inbuilt mechanical advantage adjuster, it is possible for tools of the present invention to have smaller handle members, making them less unwieldy to operate than many existing tools. Weaker handed operators might also be able to operate such tools, thus making the same tool suitable for use by a greater number of people. Smaller tools may also be capable of one handed operation, which may help to speed up the process and thus increase a worker's efficiency.

[0008] In some embodiments, the tool may be a clamping tool, such as a rivet setting tool, with the first and second application members being provided in the form of members adapted (in use) to bear against a rivet's flange and to grip the rivet's mandrel, respectively. Reciprocal displacement of the application members would thus cause the rivet to deform (i.e. in the manner described above). Advantageously, the user selectable means for adjusting the mechanical advantage of force, in use, transferred from the handgrips to these members might enable the same rivet setting tool to be used with rivets having practically any characteristics.

[0009] In alternative embodiments, the tool may be a cutting tool, such as tin snips or scissors, with the first and second application members being provided in the form of cutting blades. Reciprocal displacement of the first and second application members would, in such embodiments, move one application member past the other application member such that any material (e.g. fabric or sheet metal) therebetween would be cut. Advantageously, the user selectable means for adjusting the mechanical advantage of force, in use, transferred from the handgrips to the application members enables the same pair of scissors to be used for cutting materials having very different properties (e.g. paper and canvas).

[001 0] In accordance with a second aspect of the present invention there is provided a rivet setting tool including a first handle member with a handgrip toward one end thereof and a first application member toward the other end, a second application member supported for reciprocal sliding displacement with respect to the first application member, a second handle member having a handgrip toward one end thereof and a pivotal coupling to the first handle member toward the other end, and a linkage mechanism coupling the second handle member to the second application member. The linkage mechanism includes a user selectable means for adjusting the mechanical advantage of force, in use, transferred from the handgrips of the first and second handle members to the first and second application members.

[001 1 ] The linkage mechanism of the tool of the second aspect may include a lever arm coupled at a lever arm pivot to the first handle member. The lever arm may be coupled on one side of the lever arm pivot to the second application member, and on the other side of the lever arm pivot to the second handle member. The lever arm may be coupled to the second handle member by means of a push arm pivotally supported by the second handle member. A position of engagement of the push arm with the lever arm may be governed by a user operable selector by means of which the mechanical advantage of the tool can be adjusted. The selector may be in the form of a rotatable cam member that bears against the push arm to govern the engagement position with the lever arm.

[001 2] Where the invention is applied to a rivet setting tool, the first application member may be adapted to bear against a rivet flange, in use. The second application member may be adapted to support or grip a mandrel that is, in use, engaged with a rivet sleeve. During operation of the tool, the relative displacement between the first and second application members is effective to deform the rivet sleeve and thereby set the rivet.

[001 3] In accordance a third aspect of the present invention there is provided a hand tool including:

a first handle supporting first and second application members for displacement relative to one another to effect a clamping action;

a second handle pivotally mounted in relation to the first handle to enable user operation of the tool by squeezing the first and second handles together; and

a linkage mechanism coupling the second handle to the first and/or second application members whereby user operation of the first and second handles causes relative displacement of the first and second application members, the linkage mechanism including a user selectable means for adjusting the mechanical advantage of the tool. [0014] In accordance with a fourth aspect of the present invention there is provided a hand tool operable by squeezing action of first and second handles for effecting a clamping action through relative displacement of first and second tool application members. The tool includes a linkage mechanism coupling the second handle to the first and/or second clamping members, the linkage mechanism including a user selectable means for adjusting the mechanical advantage of forces transferred from the handles to the application members.

BRIEF DESCRIPTION OF THE DRAWINGS

[001 5] Further aspects, features and advantages of specific embodiments of the present invention may be better understood by those skilled in the relevant art by reference to the following description of embodiments taken in conjunction with the accompanying drawings, provided by way of example only, and in which:

Figure 1 A is a diagram showing the initial stage of rivet setting with use of a hand riveter;

Figure 1 B is a diagram showing the rivet while the mandrel thereof is being pulled;

Figure 1 C is a diagram showing the rivet upon completion of setting;

Figure 2 is a part-sectional elevation of the collet jaws and associated parts of a blind riveting tool with a rivet in place in the jaws;

Figure 3 is a front perspective view of a hand operated rivet setting tool according to an example of the prior art;

Figure 4 is a side view of a hand operated rivet setting tool according to an embodiment of the present invention;

Figure 5 is a front perspective view of the tool of Figure 4;

Figures 6A and 6B are side views of the tool of Figure 4 in respective open and closed configurations;

Figure 7 is an enlarged perspective view of an upper portion of the tool of Figure

4;

Figure 8 is a view corresponding to Figure 7 with several tool components removed;

Figures 9A and 9B are perspective views of some isolated components of the mechanism from the tool of Figure 4 illustrating a selector function;

Figures 10A and 1 0B are side views corresponding to Figures 9A and 9B;

Figure 1 1 is a perspective view of a selector component from the tool of Figure 4; Figure 1 2 is a side view of a lever arm component from the tool of Figure 4;

Figure 13 is a perspective view of an alternative selector component in accordance with an embodiment of the present invention ;

Figure 14 is a side view of an alternative lever arm component in accordance with an embodiment of the present invention;

Figure 15 is a side view of a quick-release bar clamp tool according to an example of the prior art, but which is capable of being adapted in accordance with the present invention;

Figure 16 is a side view of a pair of scissors according to an embodiment of the present invention; and

Figure 1 7 shows the opposite side of the scissors of Figure 16.

DETAILED DESCRIPTION

[001 6] In one aspect, the present invention provides a tool operable through a hand squeezing force applied, in use of the tool, by an operator between handgrips of first and second handle members. The tool includes a first application member supported on the first handle member, a second application member supported for reciprocal displacement relative to the first application member, and a linkage mechanism coupling the second handle member to the second application member. The linkage mechanism includes a user selectable means for adjusting the mechanical advantage of force, in use, transferred from the handgrips to the application members.

[001 7] The linkage mechanism in the tool of the present invention couples the second handle member to the second application member such that, during use, squeezing the handgrips of the (pivotally coupled) first and second handle members causes the desired reciprocal displacement of the first application member relative to the second application member.

[001 8] The form of the linkage mechanism in a tool in accordance with the present invention will depend on factors including the relative configuration of the other components of the tool (primarily the handles and application members), the tool's intended purpose and the nature of the reciprocal displacement of the first and second application members. In some embodiments (e.g. as is the case for the scissors described below), the linkage mechanism may include only one component that directly couples the second handle member to the second application member. In other embodiments, however (e.g. as is the case for the rivet setting tool described below), the linkage mechanism may include a number of components, such as, for example, a lever arm and additional pivots, via which the second handle member and the second application member are coupled.

[001 9] In embodiments where the linkage mechanism includes only one component that directly couples the second handle member to the second application member, the linkage mechanism may, for example, include a push arm, one end of which may be pivotally supported by the second handle member and the other end of which may engage the second application member at an appropriate position (i.e. in order to cause the necessary reciprocal displacement upon squeezing of the handgrips).

[0020] If a cutting reciprocal displacement is required, for example, the second application member may, in some embodiments, be pivotally coupled to the first handle member at an application member pivot. In such embodiments, the linkage mechanism may include a push arm, with one end of the push arm being pivotally supported by the second handle member and the other end of the push arm engaging the second application member on a distal side of the application member pivot (i.e. the push arm engages the side of the second application member that is on the opposite side of the application member pivot to the cutting side of the second application member).

[0021 ] As would be appreciated, movement of the second handle member of tools in accordance with such embodiments would cause a corresponding movement of the second application member (with a user selectable amount of mechanical advantage, as described below).

[0022] In embodiments where the linkage mechanism includes other components, such may, for example, be provided in the form of a lever arm coupled to the first handle member at a lever arm pivot. Such a lever arm may, for example, be coupled on one side of the lever arm pivot to the second application member and on the other side of the lever arm pivot to the second handle member. Movement of the second handle member of tools in accordance with these embodiments would cause a corresponding movement of the lever arm and, via the lever arm pivot, movement of the second application member. As would be appreciated, depending on the relative distances between the lever arm pivot and the other components, a mechanical advantage may be provided by such a configuration. Even if not, however, such a configuration alters the direction of an applied force, whereby a squeezing action of the tool's handles causes an expansion of the application members (i.e. as is required by a riveting tool).

[0023] In some embodiments, the lever arm may be coupled to the second handle member by a push arm that is pivotally supported by the second handle member (i .e. a similar push arm to that described above).

[0024] As will be appreciated by persons skilled in the art, other components (or configurations of components) may advantageously be incorporated into the linkage mechanism in accordance with the teachings disclosed herein in order to provide tools having additional functionality or advantages.

[0025] The linkage mechanism of the tools of the present invention includes a user selectable means for adjusting the mechanical advantage of force, in use, transferred from the handgrips to the application members. Any means which are operable by a user to adjust components of the tool in a manner whereby a mechanical advantage of force transferred from the handgrips to the application members may be used in the present invention.

[0026] In some embodiments, for example as noted above, the linkage mechanism may include a push arm, one end of the push arm being pivotally supported by the second handle member and the other end of the push arm engaging either the lever arm or the second application member (i.e. depending on whether or not the linkage mechanism includes the linking arm described above).

[0027] In such embodiments, a position of engagement of the push arm with the second application member or the lever arm may be governed by a user (e.g. via a user operable selector). Operation of such a selector can adjust the mechanical advantage of force, in use, transferred from the handgrips to the application members, as will be described below by way of example only.

[0028] Moving the position at which the push arm engages either the second application member or the lever arm will affect the mechanical advantage afforded by the tool. Moving the push arm closer to the respective pivot point will decrease the mechanical advantage, whilst moving the push arm away from the respective pivot point will increase the mechanical advantage. Thus, for the same handle operation, adjusting the position of the push arm with respect to the second application member/lever arm effects a variable mechanical advantage. The amount of such a mechanical advantage can be predetermined in order to provide two or more states, for example, one in which there is only a standard mechanical advantage and another (or others) in which there is an enhanced mechanical advantage.

[0029] In some embodiments (e.g. in the case of some of the cutting tools described herein), it will be appreciated that altering the mechanical advantage of the tool will also affect the relative movements of the handles and the cutting blades/application members. With no mechanical advantage selected, a movement of the handles would usually correspond to the amount of movement of the cutting blades (i.e. opening and closing the handles would cause a corresponding opening and closing of the cutting blades). However, once a mechanical advantage is selected, opening and closing the handles will cause only partial opening and closing of the cutting blades. Thus, only an inner portion (i.e. that closest to the pivot point) of the cutting blades will effect a cutting action, albeit at a mechanical advantage, with the amount of the cutting blades able to cut depending on the degree of mechanical advantage selected by the user.

[0030] It is envisaged that such an operation may provide a number of advantages in addition to the mechanical advantage described above. In particular, it is envisaged that the accuracy of cutting will be improved due to the combination of mechanical advantage and reduced cutting blade movement. Instead of one stroke of the handles corresponding to one stroke of the cutting blades, smaller increments of the cutting blades occur, with only a portion of the cutting blades closest to the pivot point between the blades being used. As would be appreciated, a user's degree of control over the cutting blades diminishes as the portion of the cutting blades doing the cutting moves further from the pivot point between the blades and handles (with the lowest amount of control right at the very tip of the cutting blades). Thus, cutting using the full movement of the handles but with only partial closing of the cutting blades (with a mechanical advantage) may enable the user to exercise a higher degree of control over the cutting blades than would be possible for prior art cutting tools. Furthermore, such fine control of the cutting blades does not require a corresponding fine control of the handles, providing the user with more tolerance in the cutting movement.

[0031 ] Any suitable mechanism that is operable by a user and which can move the push arm with respect to the second application member or the lever arm may be used. Suitable mechanisms include, for example, twisting and sliding mechanisms. One specific form of user operable selector includes a rotatable cam member that bears against the push arm to govern the position of engagement with the second application member or the lever arm. Such a rotatable cam member will be described in further detail below.

[0032] The tools of the present invention include a first application member supported on the first handle member and a second application member supported for reciprocal displacement relative to the first application member. As would be appreciated, the nature of the first and second application members and their reciprocal displacement will depend on the intended purpose and function of the tool.

[0033] In specific embodiments, for example, the tool is a rivet setting tool and the first application member includes a nose piece for receiving a rivet, and the second application member include a mandrel gripping means. In such embodiments, reciprocal displacement of the first and second application members corresponds to a lateral movement of the nose piece with respect to the mandrel gripping means.

[0034] In other specific embodiments, the first and second application members may include opposing cutting blades that are pivotally connected. In such embodiments reciprocal displacement of the first and second application members corresponds to a cutting movement of the opposing cutting blades.

[0035] Tools specifically contemplated by the present invention include tools which operate using a clamping-type mechanism, such as riveting tools and clamps, and tools which operate using a cutting-type mechanism, such as scissors and tin snips. Each of these tools is provided with application members, handles and other components where necessary, appropriately configured for their intended use. Specific embodiments of tools of the present invention are described in detail below, and it is within the ability of a person skilled in the art to adapt the teachings disclosed herein to other, similar, tools.

[0036] Features of tools in accordance with the first aspect of the present invention have been generalised above. Such generalisations are also applicable mutatis mutandis to the second, third and fourth aspects of the present invention.

[0037] Specific embodiments of the tools of the present invention will now be described below with reference to the Figures. [0038] Figures 1 A, 1 B and 1 C illustrate the process of how a rivet 1 0 is set by a hand riveting tool. The rivet 10 comprises a rivet sleeve 2 having a flange 1 at its one end, and a mandrel 4 headed as at 3 and inserted through the rivet sleeve 2, with the head 3 at the other end of the sleeve (Figure 1 A). The rivet head 3 and sleeve 2 is inserted through the workpieces 5, 5' to be riveted, and the mandrel 4 is pulled by the hand riveter to deform the sleeve 2 (Figure 1 B), whereby the workpieces 5, 5' are firmly joined together by the flange 1 , on the one side, and the sleeve end 2, on the other side, which has been radially outwardly deformed by the head 3 (Figures 1 B and 1 C). The setting operation fractures the mandrel 4 adjacent the head 3 (Figure 1 C), and the mandrel is discarded.

[0039] Referring to Figure 2, the head portion 15 of a riveting tool is shown having a tubular housing 20 which is fixed at one end of one of the handles of the tool (not shown in this illustration). A jaw assembly of the tool is received within the housing 20, the jaw assembly including a member 25 arranged for reciprocal sliding motion within the housing 20, the respective motions being indicated by arrows 26a and 26b. The member 25 is coupled at a pivotal connection 27 to the other handle of the tool (not shown in this illustration). When the handles of the tool are pulled together, which is the action for setting a rivet, the mechanical arrangement of the tool causes the slidable member 25 to move in the direction of arrow 26a.

[0040] The member 25 contains a longitudinal bore 28 housing a two-part collet 29, 29'. The forward end of the bore 28is formed with a taper as shown and the external surfaces of the collet 29, 29' are formed with corresponding tapers. It will be appreciated that the collet 29, 29' is able to receive the mandrels of blind rivets of different diameters according to the extent by which the nose of the collet extends out of the bore 28 of the member 25. The collet 29, 29' is urged forwardly (i.e. towards the workpiece, in use) by a plunger 30 and a coil spring 31 acting between the plunger 30 and the pivot 27. A nipple 21 is screwed into the nose of the housing 20 and has a bore therethrough, which is appropriate to the size of the mandrel 4 of a blind rivet 10. Different sized nipples, having different sized bores, may be fitted to the tool in order to accept rivets having mandrels of different diameters.

[0041 ] In operation, the mandrel 4 of a rivet 10 is inserted into the bore of the nipple 21 until the flange 1 rests against the forward end thereof. The mandrel 4 extends between the collet jaws 29, 29', which have teeth formations on the inside for gripping the mandrel shaft. When the slidable member 25 is drawn backwards (i.e. in the direction of arrow 26a) by action of the handle at pivot 27, the collet jaws 29, 29' are forced to clamp onto the shaft of the mandrel 4 and draw it backwards also. This effects a relative displacement between the rivet head 3 (connected to the mandrel 4) and flange 1 (abutting against the nipple), causing the deformation of sleeve 2. Thus, the action of the tool on the rivet causes the workpieces 5, 5' to be clamped between the flange 1 on one side of the rivet 10 and the deformed portion of sleeve 2 on the other side. Eventually, the member 25 moves far enough in the direction of arrow 26a that the mandrel 4 snaps (as shown in Figure 1 C).

[0042] Figure 3 illustrates a typical hand tool 40 for setting blind rivets using a simple lever mechanism to effect the rivet setting action as described above. The housing 20, with nipple 21 on the front, is supported on one end of a fixed handle 41 . The rear of the slidable member 25 is coupled to one end of a moveable handle 43 at pivot coupling 27. The other ends of the elongate handles 41 , 43 are provided with hand grips 42, 44. The fixed and moveable handles 41 and 43 are coupled to one another by a pivot pin 45, located between the pivot coupling 27 and the handle hand grips 42, 44. In use, the handle 43 is pivotally moveable about pivot pin 45 with respect to handle 41 , which effects movement of the slidable member 25 relative to housing 20 (i.e. in the direction of arrows 26a and 26b in Figure 2).

[0043] The tool 40 uses moveable handle 43 in a simple lever action with pivot pin 45 as the fulcrum. The length of the load arm is determined by the separation between the fulcrum (i.e. pivot pin 45) and the load point (pivot 27), and the length of the force application arm corresponds to the length of the handles from the fulcrum (pivot 45) to the hand grips (42, 44). During the action of setting a rivet, the mechanical advantage provided by such an arrangement is broadly determined by the length ratio of the force application arm to the load arm. In this mechanism the amount of mechanical advantage is fixed, resulting in tool 40 being suitable for many applications but suffering the problems described above.

[0044] An embodiment of the present invention is described hereinbelow, in the form of a tool for setting blind rivets, with particular reference to Figures 4 to 12 of the drawings. The tool 1 00 is shown in side view in Figure 4. For convenience of reference, the following description adopts a directional convention with respect to the tool as seen in Figure 4, wherein the "forward" direction is to the left of the page, and the "upward" direction is toward the top of the page. Additionally, axes of pivotal movement as described hereinbelow, unless explicitly specified otherwise, are perpendicular (i.e. into and out from the page) to the tool as seen in the view of Figure 4. Thus, where directional references of such a nature are made throughout the following description it is to be understood that these relate to the orientation of the tool as seen in Figure 4.

[0045] The tool 100 as shown has a first handle 150, with a hand grip 152 toward the lower end thereof, and a tool head 1 15 at the opposite, upper end. The tool head 1 1 5 includes a housing 120 which supports a slidable member 125 for reciprocal forward/backward sliding motion within the housing 120. The tool head 1 1 5 may employ a mechanical construction similar to that shown and described in relation to Figure 2, for example and therefore, in the interests of simplicity of representation and description, detailed drawings and description of the componentry of the tool head 1 15 are not included. Nevertheless, to reiterate in functional terms, the tool head 1 1 5 is adapted to receive the mandrel of a rivet 1 1 0 when inserted into an aperture at the front, and grasp the mandrel in use to enable application of force in a rearward direction in order to set the rivet. As understood from the previous description, the front end of the slidable member 125 contained within the housing 120 may have collet jaws (not shown) for grasping the rivet mandrel, whilst at the rear end is a pivot coupling 127.

[0046] Beneath the tool head 1 15 a lug plate 155 projects rearwardly from the first handle 150. A second handle 160 is pivotally coupled at a handle pivot 1 65 toward the rear extent of the lug plate 155. The second handle 1 60 has a hand grip 162 toward its lower end. Intermediate the first 150 and second 160 handles is a lever arm 170 pivotally coupled to the lug plate 155 at lever pivot 175. Toward one end, the lever arm 1 70 is coupled to the rear of the slidable member 1 25 at head pivot 1 27. Toward the other end the lever arm 170 is formed with a selector slot 178, wherein the selector slot 178 and head pivot 127 are opposite one another with respect to the lever pivot 1 75. The selector slot 1 78 is relatively elongate in a radial direction with respect to the lever pivot 1 75.

[0047] Beneath the handle pivot 165 the second handle 160 supports a push arm 180 on a push arm pivot 1 85. The push arm 1 80 projects generally forward to a push arm dog 190 that engages in the selector slot 1 78 of the lever arm 170. The position of the push arm dog 190 within the elongate selector slot 1 78 is governed by a user operable selector 200, the structure and operation of which is described further hereinbelow. [0048] The front perspective view of the tool 100 presented in Figure 5 illustrates the bifurcated structure of the second handle 160 and the lever arm 170 in this exemplary embodiment. A fastening means 172, such as a bolt or pin with a bushing, is provided at the top of the lever arm 170 to assist in fastening the two plate portions of the lever arm 170 together. Similarly, a fastening means 164 is provided in a central location on the second handle 160 to assist in fastening together the two plate portions thereof. The lug plate 1 55 and the push arm 180 are located between the two portions of the second handle 1 60 and lever arm 170. This form of structure allows for the tool 100 to be substantially symmetrical, which reduces unwanted torsional forces on the pivotal couplings, but is not necessary for the tool to operate. In alternative embodiments (not shown), a symmetrical structure may be obtained through use of a bifurcated lug plate and/or push arm if desired. It will be understood, however, that the precise form of the mechanical components of the tool may vary whilst still performing the same function, and may be adapted according to the manner in which the components and/or tool is manufactured in practice.

[0049] The pivotal couplings between the components of the tool 100 may be accomplished through various means, such as pins, bearings, bolts, rivets or the like, together with accessories and/or fastenings such as bushings, nuts, clips, etc. where applicable. Moreover, the coupling between the lever arm 170 and the slidable member 125 may be in the form of a hook or some other kind of bearing mechanism, rather than a pivotal coupling, as will be recognized by those skilled in the art, to allow for an arcuate motion of the lever arm to be translated to a linear travel of the slidable member.

[0050] Figures 6A and 6B are side views illustrating the tool 100 in open and closed configurations, respectively. In the open configuration shown in Figure 6A, the hand grips (152, 162) of the first and second handles 150, 1 60 are separated from one another and the slidable member 125 is at its furthest forward extent in the housing 120. With the tool 100 in this configuration a rivet mandrel may be inserted into the front of the tool head 1 1 5. In use, to operate the tool 100 for setting a rivet, the hand grips 1 52, 1 62 of the first and second handles 150, 160 are manually forced toward one another. Since the head 1 1 5, which in use holds the rivet in relation to the workpiece, is attached to the first handle 150, manual operation of the tool typically involves the first handle 150 remaining relatively stationary with the second hand grip 1 62 being brought toward the first hand grip 152 as indicated by arrow 101 in Figure 6B. This action brings the tool to the closed configuration where the first and second hand grips 152, 162 are substantially adjacent, as shown.

[0051 ] Operation of the second handle 160 toward the closed configuration causes the push arm dog 1 90 to bear against the forward surface of the selector slot 178 in the lever arm 170. Thus, force applied to the second handle 160 is transferred through the push arm 1 80 to the lower portion of the lever arm 1 70, where the push arm dog 190 bears against the lever arm 1 70. This forward force is translated through the lever arm 170 and lever pivot 175 into a rearward force on the slidable member 125 though its coupling 127 to the lever arm 1 70. Accordingly, as the second handle grip 162 is brought forward toward the first handle grip 152, the slidable member 125 is drawn backward relative to the housing 1 20, as indicated by arrow 102. The tool 1 00 may include a handle bias spring (not shown in the drawings) to bias the handle grips away from one another (i.e. to bias the handles into an initial rivet receiving configuration).

[0052] The mechanical advantage of the tool 100, e.g. the amount of force that can be generated at the tool head 1 15 for a given application of force on the handle grips 152, 162, is determined by the geometry of the tool components. Generally speaking, the mechanical advantage for the tool 100 is determined by the product of: 1 ) the ratio of separations of push arm dog 1 90 and coupling 127 from lever pivot 175; and 2) the ratio of separations of hand grip 1 62 and push arm coupling 185 from handle pivot 1 65. The larger those ratios are. the greater the mechanical advantage provided by the tool. Also, the larger the mechanical advantage, the smaller the travel of the slidable member 125 for a given displacement of the hand grip 162. The mechanical advantage may be readily increased by simply lengthening the handles; however beyond a certain handle length the tool will become unwieldy and likely require two handed operation, which may be undesirable.

[0053] As described above, the tools of the present invention include a user selectable means for adjusting the mechanical advantage of force, in use, transferred from the handgrips to the application members. Embodiments of the present invention described herein provide a selector mechanism whereby the mechanical advantage provided by the tool can be selectively altered by the user. The structure and operation of the selector mechanism is described hereinbelow with particular reference to Figures 7 and 8 of the drawings, which illustrate the upper portion of the tool 1 00 from a front perspective view, with some components having been removed in Figure 8 for better view of the underlying parts.

[0054] The selector mechanism functions by governing the configuration of the push arm 180 with respect to the selector slot 1 78. In particular, the selector mechanism is used to control the location within the selector slot 178 at which the push arm dog 190 engages the lever arm 170, in use. Bearing in mind the explanation of the mechanical advantage presented above, the further away from lever pivot 1 75 that the push arm 180 engages with the lever arm 170, the greater is the mechanical advantage.

[0055] In the illustrated embodiment, the selector mechanism employs a cam member 200 that is rotatably supported by the second handle 160. The location of the selector cam member 200 is adjacently above the push arm 180, intermediate the push arm pivot 185 and push arm dog 190. The selector mechanism also includes a bias spring (not shown in the Figures) provided to urge the push arm 180 upwards (i.e. in a clockwise sense about pivot 1 85). Spigot 210 (see Figure 8) is provided for the bias spring to act against. The selector cam member 200 has a switch arm 202 accessible on one side of the tool, by means of which the user can rotate the cam member 200. In a first position, with the switch arm 202 pointing upward (as seen in Figures 7 and 8), the cam member 200 holds the push arm 180 down against the spring bias so that the push arm dog 190 is forced to engage with the lever arm 1 70 toward the bottom of the selector slot 178. In a second position of the cam member, with the switch arm pointing downward (see Figures 9A and 1 0A, described below), the shape of the cam member 200 allows the push arm 1 80 to be urged upward by the bias spring to a position where the push arm dog 190 is able to engage with the lever arm 170 toward the top of the selector slot 1 78. Operation of the selector mechanism is further described with reference to Figures 9 and 10, below.

[0056] Figures 9A and 9B are front perspective views of some components of the tool 100 isolated for the purpose of explaining the selector mechanism. Figures 10A and 10B show the same components, but in side view. Figures 9B and 1 0B illustrate the selector mechanism with the cam member 200 in the aforementioned first position, whilst in Figures 9A and 10A, the selector mechanism is shown with the cam member 200 in the second position. As seen, when the selector mechanism is configured with the cam member 200 in the first position, the push arm dog 1 90 is positioned toward the bottom of the selector slot 178. On the other hand, when the selector mechanism is configured with the cam member in the second position, the push arm dog 190 is positioned toward the top of the selector slot 178. Thus, the first position of the switch arm 202 corresponds to a tool configured for greater mechanical advantage than the second position of the switch arm 202.

[0057] Figure 1 1 is a perspective view of the selector cam member 200 in isolation. In this drawing the cam bearing surfaces 204 and 206 can be more clearly discerned. These are the surfaces that govern the positioning of the push arm 180, in use. When the cam member 200 is in the first position, it is surface 206 that is arranged to bear against the push arm 180 (as can be seen in Figure 9B, for example). When the cam member 200 is in the second position, it is surface 204 that is arranged to bear against the push arm 1 80 (Figure 9A). As seen in Figure 1 1 , with respect to the axis of the cam member 200, the bearing surface 206 has a greater radial displacement than the bearing surface 204. It is this difference in radial displacements of the bearing surfaces 204, 206 that effects the change in push arm 1 80 positioning when the selector is moved from one position to another.

[0058] Figure 12 is a side elevation of the lever arm 1 70 in isolation, giving a clear view of the selector slot 1 78. It can be seen that the surface of the lever arm 1 80, within the selector slot 1 78, against which the push arm dog 190 bears, in use, is formed with indentations 174 and 176 for improved location of the push arm dog 190. The two indentations 176, 174 are the locations where the push arm dog 190 bears against the lever arm 170 when the selector 200 is in the first and second positions, respectively.

[0059] Whilst the embodiment described above allows the user to adopt one of two configurations of the selector, it is also possible to provide more than two selection positions. For example, Figure 13 shows, in isolation, a selector cam member 200' adapted for three different configurations of the tool. As shown, the selector cam member 200' has three cam bearing surfaces 204', 205', 206' , each of which has a different radial displacement from the axis of the cam member. This allows the user to manipulate the switch arm 202', in use, to place the tool in any one of three different configurations characterized by the position of the push arm dog 190 in the selector slot. Figure 14 shows a correspondingly formed lever arm 170' having three different indentations 174', 177', 176' within the selector slot 178'. [0060] Other variations of the selector mechanism are also possible. For example, whilst the selector has been above described with a plurality of discrete configurations defined by separate cam bearing surfaces, the cam member may alternatively have a continuously varying cam bearing surface. In such a case, the selector cam member may be maintained in a desired rotational position using an indexing formation or some form of tightening structure. Moreover, the selector mechanism need not employ a rotating cam member as described above and may equally comprise a sliding or pushbutton member arranged to govern the position of engagement of the push arm with the lever arm. Furthermore, whilst the above embodiments have the push arm pivoting on the second handle in order to control the position of engagement with the lever arm, it is also possible to reverse that arrangement so that the push arm pivots on the lever arm and the selector mechanism controls a position of engagement of the push arm with the second handle. Another possibility is that the pivotal couplings of the second handle and lever arms on the lug plate could be reversed, in which case the push arm would in effect be a 'pull arm' by transmitting force from the second handle to the lever arm through tension rather than compression.

[0061 ] Whilst the above embodiment has been described in the context of a blind rivet setting tool, other forms of hand tools may also benefit from a mechanism for providing selectable mechanical advantage. For example, another type of rivet known as a rivet nut (also known as a blind nut, rivnut, threaded insert or nut-sert) is a one-piece internally threaded and counter-bored tubular rivet that can be anchored entirely from one side. Rivet nuts may be installed using a hand tool that is similar to the blind rivet setting tool described above, but the mandrel forms part of the tool, rather than the rivet unit itself. Instead of an aperture at the front of the tool head for receiving a rivet mandrel, a rivet nut setting tool has an externally threaded tool mandrel projecting therefrom. The tool mandrel is supported by the slidable member for axial rotation. In use, the external thread on the end of the tool mandrel is engaged with the internal thread of a rivnut sleeve prior to installation. The rivet is then set in much the same way as described above, by effecting relative displacement between the tool mandrel and the tool head housing which bears against a flange of the rivnut sleeve. Once the rivnut sleeve has been deformed and clamped onto the workpiece, instead of the mandrel fracturing it is rotated to unscrew from its engagement with the rivnut sleeve. [0062] The functional effect of the above described rivet setting tools is a clamping action. A manual squeezing action of the handles is translated into a relative displacement of first and second clamping members in the form of the head housing and slidable member, which results in the rivet sleeve being deformed so as to clamp onto the workpiece. Considering this, those skilled in the art may recognize how the principles of the present invention can be applied to other kinds of hand tools, particularly those involving a clamping action. The kinds of tools that could benefit from incorporation of a user selectable adjustable advantage linkage mechanism according to embodiments of the invention may include quick-release bar clamps, frame clamps, pliers, vice-grips and the like. Application to a bar clamp is described briefly below.

[0063] A bar clamp operated with one hand is used to clamp onto a workpiece, and is more convenient than a bar clamp that requires two hands to operate. With reference to Figure 15, a conventional bar clamp 300 comprises a slidable member 325 (including a slide bar 370 and movable jaw 372), a stationary member 320 (including a stationary jaw 371 ), a body 373, a drive assembly and a brake 376. The movable jaw 372 opposes the stationary jaw 371 and is mounted at one end of the slide bar 370 that is movably mounted through the body 373. The slide bar 370 has a top edge and a bottom edge.

[0064] The body 373 has a top, a bottom, a front edge, a cavity 331 , a transverse hole 332 and a first handle 350. The stationary jaw 371 is formed on the top of the body 373. The cavity 331 is defined in the body 373 and the slide bar 370 passes through the cavity 331 . The transverse hole 332 is formed in the front edge of the body above the slide bar 370. The handle 374 is formed at the bottom of the body 373.

[0065] The drive assembly comprises a second handle 360, a drive lever 351 and a spring 352. The second handle 360 has a top, a bottom, a front edge and rear edge and is pivotally mounted in the body 373 corresponding to the first handle 350 so the top of the second handle 360 is in the cavity 331 . The drive lever 351 has a front surface, a rear surface and a hole (not numbered) through which the slide bar 370 passes, is suspended on the slide bar 370 and abuts the rear edge of the second handle 360. The hole of drive lever 351 has a top edge and a bottom edge. The spring 352 has two ends and is mounted around the slide bar 370 in the cavity 331 . One end of the spring 352 abuts the drive lever 351 , and the other end abuts an interior surface of the cavity 331 . [0066] The brake 376 has a central hole and is pivotally attached to the transverse hole 332 in the front edge of the body 373. The slide bar 370 passes through the central hole in the brake 376. The central hole in the brake 376 has a top edge and a bottom edge. A compression spring 362 is mounted between the brake 376 and the front edge of the body 373 so the brake 376 is pushed to an inclined standby position.

[0067] To move the movable jaw 372 toward the stationary jaw 371 , second handle 360 is squeezed toward the first handle 350, and the second handle pivots the drive lever 351 . The hole in the drive lever 351 is inclined so the top and bottom edges of the hole grip the top and bottom edges of the slide bar 370 and push the slide bar back. As the drive lever 351 pushes the slide bar back, the movable jaw 372 moves toward the stationary jaw. The slide bar is kept from moving forward by the brake 376 because the central hole in the brake grips the top edge and bottom edge of the slide bar when the second handle 360 is released. The compression spring 362 keeps the brake 376 in position to grip the slide bar 370 to prevent the slide bar from moving forward.

[0068] Considering the structure and functional action of the prior art bar clamp and its parallels with the prior art pop rivet setting tool previously described, those skilled in the art will recognize the manner in which a user selectable adjustable advantage linkage mechanism, similar in nature to that applied to the tool 1 00, may also be applied to a bar clamp. For example, rather than the second handle 360 engaging the drive lever 351 directly, a lever arm and push arm with selectable advantage engagement may be interposed therebetween. In such a modification, the lever arm may be supported by the body 373 for pivotal action at the pivot point 375 conventional supporting the second handle 360, and the second handle shifted forward to accommodate the linkage mechanism. As with the rivet setting tool, a push arm may be mounted to the second handle together with a selector mechanism to control the position of engagement of the push arm with the lever arm.

[0069] Referring now to Figures 16 and 17, a tool in accordance with another embodiment of the present invention is shown in the form of scissors 400. Scissors 400 have a first handle 402, a second handle 404, a first application member in the form of blade 406, which is integrally formed with first handle 402, and a second application member in the form of blade 408. Blade 408 is provided at one end of a member 410, the other end of the member 410 being located between the first 402 and second 404 handles and having a selector slot 41 2 therein. Selector slot 412 is similar in appearance and operation to selector slot 178', shown in Figure 14, and will be described in further detail below.

[0070] The member 410 is pivotally coupled to first handle 402 and blade 406 via pivot coupling 414. The second handle 404 is pivotally coupled to first handle 402 via pivot coupling 416. Opening and closing of handles 402, 404 causes a reciprocal displacement in the form of a cutting movement of blades 406, 408, via the linkage mechanism described below. The scissors 400 also include a spring (not shown), which biases the arms 402, 404, and hence the blades 406, 408, into an open configuration (not shown).

[0071 ] Scissors 400 also include a linkage mechanism which couples the second handle 404 to the member 410 in the form of push arm 418. Push arm 418 is pivotally coupled to second arm 404 at push arm pivot 420 at one end thereof, with its other end including a push arm dog 422 (which cannot clearly be seen in Figures 16 and 1 7) that is positioned within and able to bear on the indented edge of selector slot 41 2. As will be appreciated from the discussions regarding mechanical advantage set out above, the position in slot 41 2 on which the push arm dog 422 is brought to bear will affect the mechanical advantage of force, in use, transferred from the handles 402, 404 to the blades 406, 408.

[0072] The scissors 400 also include a user selectable means for adjusting the mechanical advantage in force transferred in use from handles 402, 404 to blades 406, 408, in the form of cam member 424. Cam member 424 is operable in a manner similar to that described above in respect of cam members 200 and 200' in order to selectively move the push arm 418 (and more particularly, the push arm dog 422) between the indentations within the selector slot 412. The selector slot 41 2, in the depicted embodiment, provides for three user selectable settings, with maximum, medium and minimum mechanical advantages being provided as the push arm dog 422 moves away from the pivot coupling 414.

[0073] As would be appreciated, cutting tools similar to scissors 400 but having varying characteristics and functionality could be obtained by varying the relative positions of pivot couplings 414, 41 6 and 420. [0074] Scissors 400 also have a pivoting lock 426, which is positionable as shown in Figures 16 and 17 in order to hold handles 402, 404 and, more particularly, blades 406, 408 in their closed position.

[0075] While this invention has been described in connection with specific embodiments thereof, it will be understood that it is capable of further modification(s). This application is intended to cover any variations uses or adaptations of the invention following in general, the principles of the invention and including such departures from the present disclosure as come within known or customary practice within the art to which the invention pertains and as may be applied to the essential features hereinbefore set forth.

The following sections I and II provide a guide to interpreting the present specification. I. Terms

[0076] The term "product" means any machine, manufacture and/or composition of matter, unless expressly specified otherwise.

[0077] The term "process" means any process, algorithm, method or the like, unless expressly specified otherwise.

[0078] Each process (whether called a method, algorithm or otherwise) inherently includes one or more steps, and therefore all references to a "step" or "steps" of a process have an inherent antecedent basis in the mere recitation of the term 'process' or a like term. Accordingly, any reference in a claim to a 'step' or 'steps' of a process has sufficient antecedent basis.

[0079] The term "invention" and the like mean "the one or more inventions disclosed in this specification", unless expressly specified otherwise.

[0080] The terms "an embodiment", "embodiment", "embodiments", "the embodiment", "the embodiments", "one or more embodiments", "some embodiments", "certain embodiments", "one embodiment", "another embodiment" and the like mean "one or more (but not all) embodiments of the disclosed invention(s)", unless expressly specified otherwise. [0081 ] The term "variation" of an invention means an embodiment of the invention, unless expressly specified otherwise.

[0082] A reference to "another embodiment" in describing an embodiment does not imply that the referenced embodiment is mutually exclusive with another embodiment (e.g., an embodiment described before the referenced embodiment), unless expressly specified otherwise.

[0083] The terms "including", "comprising" and variations thereof mean "including but not limited to", unless expressly specified otherwise.

[0084] The terms "a", "an" and "the" mean "one or more", unless expressly specified otherwise.

[0085] The term "plurality" means "two or more", unless expressly specified otherwise.

[0086] The term "herein" means "in the present specification, including anything which may be incorporated by reference", unless expressly specified otherwise.

[0087] The phrase "at least one of", when such phrase modifies a plurality of things (such as an enumerated list of things), means any combination of one or more of those things, unless expressly specified otherwise. For example, the phrase "at least one of a widget, a car and a wheel" means either (i) a widget, (ii) a car, (iii) a wheel, (iv) a widget and a car, (v) a widget and a wheel, (vi) a car and a wheel, or (vii) a widget, a car and a wheel. The phrase "at least one of", when such phrase modifies a plurality of things, does not mean "one of each of" the plurality of things.

[0088] Numerical terms such as "one", "two", etc. when used as cardinal numbers to indicate quantity of something (e.g., one widget, two widgets), mean the quantity indicated by that numerical term, but do not mean at least the quantity indicated by that numerical term. For example, the phrase "one widget" does not mean "at least one widget", and therefore the phrase "one widget" does not cover, e.g., two widgets.

[0089] The phrase "based on" does not mean "based only on", unless expressly specified otherwise. In other words, the phrase "based on" describes both "based only on" and "based at least on". The phrase "based at least on" is equivalent to the phrase "based at least in part on". [0090] The term "whereby" is used herein only to precede a clause or other set of words that express only the intended result, objective or consequence of something that is previously and explicitly recited. Thus, when the term "whereby" is used in a claim, the clause or other words that the term "whereby" modifies do not establish specific further limitations of the claim or otherwise restricts the meaning or scope of the claim.

[0091 ] The term "e.g." and like terms mean "for example", and thus does not limit the term or phrase it explains. For example, in the sentence "the car travels along a path (e.g., on a road or track)", the term "e.g." explains that "a road" is an example of "a path" that the car may travel along, and also explains that "a track" is an example of "a path" that the car may travel along. However, both "road" and "track" are merely examples of "path", and other things besides "road" and "track" can be "path".

[0092] The term "i.e." and like terms mean "that is", and thus limits the term or phrase it explains. For example, in the sentence "the car is propelled by a motive force (i.e., an engine) along the road", the term "i.e." explains that an "engine" provides the "motive force" that propels the car along the road.

[0093] Any given numerical range shall include whole and fractions of numbers within the range. For example, the range "1 to 10" shall be interpreted to specifically include whole numbers between 1 and 1 0 (e.g., 2, 3, 4, . . . 9) and non-whole numbers (e.g., 1 .1 ,

I .2, . . . 1 .9).

II. Disclosed Examples and Terminology Are Not Limiting

[0094] Neither the Title nor the Abstract in this specification is intended to be taken as limiting in any way as the scope of the disclosed invention(s). The title and headings of sections provided in the specification are for convenience only, and are not to be taken as limiting the disclosure in any way.

[0095] Numerous embodiments are described in the present application, and are presented for illustrative purposes only. The described embodiments are not, and are not intended to be, limiting in any sense. The presently disclosed invention(s) are widely applicable to numerous embodiments, as is readily apparent from the disclosure. One of ordinary skill in the art will recognize that the disclosed invention(s) may be practiced with various modifications and alterations. Although particular features of the disclosed invention(s) may be described with reference to one or more particular embodiments and/or drawings, it should be understood that such features are not limited to usage in the one or more particular embodiments or drawings with reference to which they are described, unless expressly specified otherwise.

[0096] The present disclosure is not a literal description of all embodiments of the invention(s). Also, the present disclosure is not a listing of features of the invention(s) which must be present in all embodiments.

[0097] A description of an embodiment with several components or features does not imply that all or even any of such components/features are required. On the contrary, a variety of optional components are described to illustrate the wide variety of possible embodiments of the present invention(s). Unless otherwise specified explicitly, no component/feature is essential or required.

[0098] Although a product may be described as including a plurality of components, aspects, qualities, characteristics and/or features, that does not indicate that any or all of the plurality are preferred, essential or required. Various other embodiments within the scope of the described invention(s) include other products that omit some or all of the described plurality.