Abstract:
A manually powered cutting tool with cutting force at the cutting jaw faces that is multiplied several times by the mechanism, leading to a much higher maximum available cutting force than possible with conventional snips. The maximum magnitude of the cutting force applied to the workpiece may be much larger due to multiple stages of force multiplication present in the mechanism. The multiplication factors are established by the structural geometry built into the tool.

Description:
[0001]     This application claims the benefit of U.S. Provisional Application No. 60/712,097, filed Aug. 29, 2005, which is incorporated herein by reference in its entirety. 
     
    
     BACKGROUND OF THE INVENTION  
       [0002]     This invention relates to snips, bolt cutters, and other cutting hand tools with increased cutting force.  
       SUMMARY OF THE INVENTION  
       [0003]     The present invention provides a manually powered cutting tool with cutting force at the cutting jaw faces that is multiplied several times by the mechanism, leading to a much higher maximum available cutting force than possible with conventional snips. The maximum magnitude of the cutting force applied to the workpiece may be much larger than possible with conventional snips, due to multiple stages of force multiplication present in the mechanism. The multiplication factors are established by the structural geometry built into the tool. 
     
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       [0004]      FIG. 1  is a schematic elevational view of a pliers, with the jaws in the fully open position.  
         [0005]      FIG. 2  is a schematic end view of the pliers, from the jaw end.  
         [0006]      FIG. 3  is a schematic elevational view like that of  FIG. 1 , after initial activation of the pliers handles.  
         [0007]      FIG. 4  is a schematic elevational view like that of  FIG. 1 , at the position where the lower jaw contacts the workpiece.  
         [0008]      FIG. 5  is a schematic elevational view like that of  FIG. 1 , as force is applied to the workpiece.  
         [0009]      FIG. 6  is a schematic elevational view like that of  FIG. 1 , as the lower handle is pivoted toward an overcenter position.  
         [0010]      FIG. 7  is a schematic elevational view of a second embodiment of the pliers, with force adjustment and a locking release.  
         [0011]      FIGS. 8-11  are a series of schematic elevational views of a third embodiment of the pliers, in an overcenter locking form, showing the closing movement of the handles and jaws, wherein  FIG. 8  shows the jaws in the open position,  FIG. 9  shows the lower jaw just contacting the workpiece,  FIG. 10  shows the lower handle approaching the overcenter position, and  FIG. 11  shows the lower handle in the overcenter position.  
         [0012]      FIGS. 12-15  are a series of schematic elevational views of the embodiment of  FIGS. 8-11 , in a non-overcenter locking form, showing the closing movement of the handles and jaw, wherein  FIG. 12  shows the jaws in the open position,  FIG. 13  shows the lower jaw just contacting the workpiece,  FIG. 14  shows the lower handle approaching the overcenter position, and  FIG. 15  shows the lower handle contacting the control arm to prevent movement to the overcenter position.  
         [0013]      FIG. 16  is a schematic elevational view of a fourth embodiment of the pliers.  
         [0014]      FIG. 17  is a schematic elevational view of a fifth embodiment of the pliers.  
         [0015]      FIG. 18  is a plan view illustrating another embodiment with the cutting faces in their open position.  
         [0016]      FIG. 19  is a view similar to  FIG. 18 , with the cutting faces closed on an article between the jaws.  
         [0017]      FIG. 20  is a plan view illustrating the assembly of the jaw and handle with their interconnecting link.  
         [0018]      FIG. 21  is a similar view of the other integrally formed handle and jaw.  
         [0019]      FIG. 22  is an edge view of the integral jaw and handle.  
         [0020]      FIG. 23  is a detail sectional view of the line  23 - 23  of  FIG. 18 . 
     
    
     DETAILED DESCRIPTION OF THE INVENTION  
       [0021]      FIGS. 1-17  illustrate a tool  20  according to the invention. The figures herein are all schematic drawings illustrating external features and internal mechanisms in a single plane, for clarity in describing the interrelationships of the elements. “Up” and “down” reference directions are indicated on several of the figures and apply to all of the embodiments.  
         [0022]     As shown in  FIG. 1  for one embodiment, the tool  20  comprises an upper arm  22  with an upper jaw  24  at a first end  26  of the upper arm  22 . The upper arm  22  has a cross-sectional shape preferably in the form of an inverted “U”, with the opening of the “U” pointing downwardly, as seen in  FIG. 2 . The upper jaw  24  preferably has a pattern of gripping ridges  28  on its lower side  30  for engaging a workpiece  32 . An upper handle  34  is at an oppositely disposed second end  36  of the upper arm  22  that is remote from the upper jaw  24 . The upper handle  34  is configured for comfortable gripping by a user operating the tool  20 , and may be contoured and/or provided with a resilient plastic covering.  
         [0023]     A support  38  is affixed to and extends downwardly from the upper arm  22  at an intermediate location between the first end  26  and the second end  36 . The support  38  desirably includes two parallel and spaced-apart support bodies  38   a  and  38   b,  as seen in  FIG. 2 .  
         [0024]     Two slots are provided in the support  38 , extending through the support bodies  38   a  and  38   b.  A first slot  40  extends downwardly and has smooth side walls. A second slot  42  extends downwardly parallel to the first slot  40 , at a location rearward of the first slot and thence closer to the upper handle  34  than the first slot  40 . (As used herein, the term “slot” includes other functionally equivalent structures, such as recesses, channels, grooves, and the like, and may include guide surfaces where the function of the slot is to act as a guide as in the case of the first slot  40 .) The two slots  40  and  42  are illustrated in  FIG. 1  as curved, and the curvature will be discussed subsequently. They are locally parallel to each other, even though curved. That is, the slots  40  and  42  have their adjacent portions substantially parallel to each other. The slots  40  and  42  may instead be straight, as shown in  FIG. 16 . A first side  44  of the second slot  42 , closest to the first slot  40 , has second-slot teeth  46  thereon. An oppositely disposed second side  48  of the second slot  42 , closest to the upper handle  34 , is smooth.  
         [0025]     A lower arm  50  has a first end  52  and an oppositely disposed second end  54 . The lower arm  50  preferably has a cross section in the form of an upwardly opening “U” shape. A lower handle  56  is present adjacent to the second end  54 . As with the upper handle  34 , the lower handle  56  is configured for comfortable gripping by a user operating the tool  20 , and may be contoured and/or provided with a resilient plastic covering. Force is applied to the workpiece  32  by the hand of the user of the tool  20  acting through the two handles  34  and  56 .  
         [0026]     A control arm  58  is pivotably connected at a first end  60  thereof to an upper control arm pivot pin  62  on the upper arm  22  at a location within or adjacent to the upper handle  34 , and adjacent to the second end  36  of the upper arm  22 . A second end  64  of the control arm  58  is pivotably connected to a lower control arm pivot pin  66  at an intermediate location between the ends  52  and  54  of the lower arm  50 .  
         [0027]     A spring  68  is affixed at a first end  70  thereof to the upper arm  22  at a location adjacent to the first end  26  of the upper arm  22 . A second end  72  of the spring  68  is affixed to a spring extension  74  of the control arm  58 . The spring extension  74  extends beyond the portion of the control arm  58  that is affixed to the upper control arm pivot pin  62 , preferably at an angle to the control arm  58 . The preferred angle between the spring extension  74  and the control arm  58  is about 45 degrees, although other angles are operable. The spring force of the spring  68  applied through the spring extension  74  serves to resist rotation of the control arm  58 , in the clockwise direction in the view of  FIG. 1 . Other spring configurations are possible to achieve this resisting of rotation of the control arm  58 , as will be discussed subsequently.  
         [0028]     The mechanisms associated with the upper arm  22 , including the first end  60  of the control arm  58 , the upper control arm pivot pin  62 , the spring  68 , and the spring extension  74 , are hidden from external view within the interior of the U-shaped upper arm  22 . Similarly, the second end  64  of the control arm  58  and the lower control arm pivot pin  66  are hidden from external view within the interior of the U-shaped lower arm  50 .  
         [0029]     A lower jaw member  76  includes a lower jaw  78  at a first end  80  thereof. The lower jaw  78  preferably has a pattern of upwardly facing gripping ridges  82  thereon. The gripping ridges  28  and  82  are in facing relationship to each other, and serve to grasp the workpiece  32  firmly therebetween.  
         [0030]     A slider  84  extends from each side of the lower jaw member  76 , as seen in  FIGS. 1 and 2 . The slider  84  is shaped and dimensioned to be received within, and to slide within, the first slot  40 . The first slot  40  thereby serves as a guide. Any other structural component that functionally serves as a guide may be used rather than the first slot  40 . Groves, guide surfaces, and channels are examples. The slider  84  is straight where the first slot  40  is straight, and is curved to match the curvature of the first slot  40 , when the first slot  40  is curved. The slider  84  is dimensioned so that its fit into the first slot  40  is sufficiently loose to prevent binding of the slider  84  to the sides of the first slot  40  during operation. The slider  84  constrains the movement of the lower jaw  78  so that it has a perpendicular or near-perpendicular incidence to the upper jaw  24  when the workpiece is grasped between the jaws. This constraint prevents any end-to-end or side-to-side relative movement of the jaws  78  and  24 , which would tend to gouge the workpiece. This constraint is an important advantage of the present invention, achieved with the use of two slots  40  and  42  rather than a single slot.  
         [0031]     A pawl  86  is captured within and disposed within the second slot  42  of each of the support bodies  38   a  and  38   b.  (That is, there are preferably two pawls  86 , but one pawl would be sufficient for the tool to operate.) Each pawl  86  has a set of pawl teeth  88  thereon, in facing relationship to the second slot teeth  46 . A second side  90  of the pawl  88 , oppositely disposed from the pawl teeth  88 , is smooth and in facing relationship to the smooth second side  48  of the second slot  42 . The functioning of the pawl  86  will be subsequently discussed in relationship to  FIGS. 3-6 . In equivalent structures to be discussed subsequently, a high-friction material may substitute the teeth  46  and  88 , or a cam may substitute for the pawl  86 .  
         [0032]     A shifter  92  is a plate that transfers force applied to the handles into the lower jaw  78 . There may be two plate shifters  92 , one associated with each of the support bodies  38   a  and  38   b.  Equivalently, there may be a single shifter  92  disposed between the two support bodies  38   a  and  38   b.  Each shifter  92  has three pivot points thereon arranged in a triangular pattern. The three pivot points on the shifter  92  are respectively connected to a lower jaw member pivot pin  94  on the lower jaw member  76 , a pawl pivot pin  96  on the pawl  86 , and a lower arm pivot pin  98  at the first end  52  of the lower arm  50 . The shifter  92  provides the interconnection between the lower arm  50 , the pawl  86 , and the lower jaw member  76 . That is, the lower jaw member  76  is not integral with the lower arm  50 , but instead is linked by a linkage, in this embodiment provided by the shifter  92 .  
         [0033]     A torsion spring  99  is wound around the lower arm pivot pin  98  and anchored on the lower arm  50 . The torsion spring  99  resists rotational movement of the lower arm  50  relative to the lower arm pivot pin  98 . As will be discussed subsequently, functionally equivalent springs may be used instead of the torsion spring  99 .  
         [0034]      FIGS. 1 and 3 - 6  provide a sequential depiction of the movement of the mechanism of the tool  20  from an initial position in  FIG. 1  to a near-final position in FIG.  6  as the handles are moved together with an applied force. Not all elements are shown and labeled in  FIGS. 3-6 , so that the operation of the mechanism is not obscured. In  FIG. 1 , the mechanism is in a relaxed, fully open position, with no force applied through the handles  34  and  56 . The workpiece  32  is not yet grasped between the jaws  24  and  78 , the slider  84  is free to slide within the first slot  40  to move the lower jaw member  76  upwardly, and the pawl  86  is free to slide within the second slot  42  with the second side  90  of the pawl  86  sliding along the second side  48  of the second slot  42 .  
         [0035]     This configuration is retained, see  FIG. 3 , as a force is applied through the arms  22  and  50  and the lower handle  56  is moved upwardly, thereby acting through the shifter  92  to move the lower jaw member  76  upwardly to approach (but not yet reach) contact to the workpiece  32 . Simultaneously, the control arm  58  pivots about the upper control arm pivot pin  62 , clockwise in the view of  FIG. 3 , so that the spring  68  extends. The spring extension creates a relatively small force that resists the upward movement of the lower handle  56 , giving the user of the tool  20  a feel for the positioning and movement of the lower handle  56 . This spring extension force also serves as a restoring force that moves the arms  22  and  50  apart to the jaw-open or relaxed position of the tool  20  shown in  FIG. 1 , if no force is applied to the handles  34  and  56 .  
         [0036]     With continued upward movement of the lower handle  56 , the lower jaw  78  contacts the workpiece so that it can no longer move upwardly, as seen in  FIG. 4 . At this point, the continued movement of the lower handle  56  causes the shifter  92  to rotate in rigid-body motion in the counterclockwise direction in  FIG. 4 . The rigid-body rotation of the shifter  92  draws the pawl  86  forwardly, engaging the pawl teeth  88  to the second-slot teeth  46 , as seen in  FIG. 5 . This engagement between the sets of teeth  88  and  46  effectively produces a new clamping pivot point, whose location along the second slot  42  varies according to the size of the workpiece  32 . The smaller the workpiece  32 , the further upwardly along the second slot  42  is the point where the sets of teeth  88  and  46  engage. With continued upwardly movement of the lower handle  56 , as in  FIG. 6 , the shifter  92  rotates about this effective clamping pivot point, causing the lower jaw member  76  to rotate about the clamping pivot point and, in cooperation with the upper jaw  24 , to apply clamping force to the workpiece  32 .  
         [0037]     In all of this movement depicted in  FIGS. 1 and 3 - 6 , the movement of the lower jaw member  76  and its lower jaw  78  is constrained by the slider  84  to travel along the first slot  40 . Also during the movement of  FIGS. 1 and 3 - 6 , the second end  64  of the control arm  58  follows a locus of points as it pivots about the upper control arm pivot pin  62 . Desirably, the first slot  40  and the second slot  42  are shaped with the same curvature as this locus of points or, alternatively stated, the first slot  40  and the second slot  42  are parallel to the locus of points defined by the second end  64 .  
         [0038]     That is, in their preferred curved configuration, the first slot  40  and the second slot  42  are each respectively segments of circles centered on the upper control arm pivot pin  62 . With this preferred configuration for the slots  40  and  42 , the clamping force applied to the workpiece  32  is the same, regardless of the size of the workpiece  32 . The closer the curvature of the slots  40  and  42  is to that of the locus of points of the second end  64  and to a segment of a circle, the closer is the clamping force to a constant value for all workpiece sizes that fit between the jaws  24  and  78 . Even if the slots  40  and  42  are straight, the variation in the clamping force is relatively small, so that straight slots  40  and  42  may be used if it is not important to maintain the clamping force exactly constant for all sizes of workpieces.  
         [0039]      FIG. 7  depicts an embodiment of the tool  20  that provides for both adjustability of the clamping force applied through the jaws  24  and  78 , and also for overcenter locking and release of the clamping force. The term “overcenter locking” is used herein in the conventional sense.  
         [0040]     These two features of force adjustability and overcenter locking and release are desirably provided together, but they may be provided separately. The basic closing and opening mode of this tool  20  of  FIG. 7  is the same as that shown in  FIGS. 1-6 . Features common to the embodiment of  FIGS. 1-6  are identified by the same numerals, and the prior discussion of  FIGS. 1-6  is incorporated herein.  
         [0041]     The clamping force adjustability is provided by moving the upper control arm pivot pin  62  in a track  100  in the upper arm  22 , along the length of the upper arm  22  in the direction between the first end  26  and the second end  36 . The maximum travel required to achieve a substantial variation in the clamping force is relatively small, and typically is about ¼ inch or less. The movement of the upper control arm pivot pin  62  along the track  100  is preferably accomplished with a screw drive  102  and a manual screw movement knob  104  that extends from the second end  36  of the upper arm  22 . This same adjustability may equivalently be provided by moving the lower control arm pivot pin  66  in a similar fashion, but this movement is not as conveniently implemented.  
         [0042]     The overcenter locking and release is conveniently provided by placement of an unlocking lobe  106  on the lower side of the control arm  58 . A release arm  108  is pivotably connected to the lower arm  50 , at a location between the first end  52  and the second end  54  and accessible to the hand of the user of the tool  20  at the second end  54 . A release pad  110  on the upper side of the release arm  108  is disposed to contact the unlocking lobe  106 . In operation, the lower control arm pivot pin  66  moves to an overcenter position relative to the upper control arm pivot pin  62  and the lower arm pivot pin  98 , when the lower handle  56  is moved upwardly to the limit of its travel. Stated alternatively, when the lower handle  56  is fully open (moved to its downward limit of travel) as in  FIG. 1 , the lower control arm pivot pin  66  lies below a straight line drawn between the upper control arm pivot pin  62  and the lower arm pivot pin  98 . As the lower handle  56  is moved upwardly, the lower control arm pivot pin  66  moves closer to a straight-line relationship between the pins  62  and  98 , and eventually crosses over that straight line to lie above the straight line drawn between the pins  62  and  98 . This is the overcenter lock position. To release the tool  20  from this overcenter lock position, the release arm  108  is operated to rotate the release pad  110  upwardly against the unlocking lobe  106 , and thereby force the lower arm  50  downwardly and out of the overcenter relationship.  
         [0043]     The embodiment of  FIG. 7  allows the tool  20  to be selectively shifted between the non-locking version and the locking/release version. An overcenter lock switch  112  is provided to selectively prevent the pivoting movement of the release arm  108 . That is, when the movement of the tool  20  passes into the overcenter relationship, the release arm  108  is forced to pivot in the direction (counterclockwise in the embodiment of  FIG. 7 ) opposite to the pivoting movement of the release arm  108  during unlocking (clockwise in  FIG. 7 ). The locking function may be prevented by preventing this counterclockwise movement of the release arm  108  as the movement reaches the overcenter position as the jaws are closed, so that the stationary release arm  108  prevents the movement of the control arm  58  from passing to the overcenter position. The overcenter lock switch  112  prevents the movement of the release arm  108  and the control arm  58  by physically contacting and interfering with the movement of the release arm  108 . Thus, in the embodiment of  FIG. 7 , the overcenter lock switch  112  slides into an interfering position relative to the release arm  108  when slid to the right, so that the overcenter locking is not permitted. (Other functionally equivalent forms of the overcenter lock switch may also be used, such as an arm that pivots between positions where it blocks the release arm  108  and where it does not block the release arm  108 .) The tool then serves as an ordinary non-locking tool. When the overcenter lock switch  112  is slid to the left in the view of  FIG. 7 , it does not interfere with the rotation of the release arm  108 , and the release arm  108  does not prevent the movement of the lobe  106  and thence the control arm  58  as it passes to the overcenter position. The tool is a locking tool in this configuration.  
         [0044]      FIGS. 8-15  illustrate another embodiment of the invention. This embodiment is similar to those of  FIGS. 1-7 , and the description of those embodiments is incorporated herein as appropriate with differences as noted next. In these figures, the labels of some elements are omitted so as not to obscure the illustration of the movement. In the embodiment of  FIGS. 8-15 , the spring  68  is connected between the second end  36  of the upper arm  22  and the spring extension  74  on the control arm  58 , rather than between the first end of the upper arm  22 . The mechanical effect in resisting rotation of the control arm  58  is functionally the same as that of the embodiment illustrated in  FIGS. 1-7 , but the spring  68  is shorter and positioned out of the way so that the remainder of the upper arm  22  may be used for other purposes as will be discussed in relation to  FIG. 17 .  
         [0045]     A second difference in the embodiment of  FIGS. 8-15  is that a shoulder  220  extends from the side of the lower jaw  78 . More preferably, two shoulders  220  are provided, one on each side of the lower jaw  78 . The curvature of the shoulder  220  is matched to that of a front side  222  of the support  38 . The sliding movement of the shoulder  220  over the front side  22  of the support  38  guides the position of the lower jaw  78 . The front side  222  of the support  38  thereby serves as a guide for the shoulder  220  in the same manner as the first slot  40  serves as a guide for the slider  84 . The shoulder  220  serves as a slider in the same sense as the slider  84 , except that it slides on a surface rather than in the first slot  40 . Either or both of these guides may be used. The use of both the shoulder  220  and the slider  84  provides a redundant guiding function that increases the strength of the guiding structure.  
         [0046]     A third difference in the embodiment of  FIGS. 8-15  is the addition of an arm  230  on the side of the shifter  92 . The arm  230  defines a recess  232  in which is received a compression spring  234 . The compression spring  234  reacts between the arm  230  on the shifter  92  and the lower arm  50 . The compression spring  234  augments or replaces the coiled torsion spring  99  of the embodiment of  FIGS. 1-7 , to provide a greater restoring force.  
         [0047]     A fourth difference is the addition of a stop  238  to the first end  52  of the lower arm  50 . The stop  238  is positioned to engage the shifter  92  to prevent the lower arm  50  from opening (rotating clockwise in the view of  FIG. 8 ) more widely than desired.  
         [0048]     A fifth difference in the embodiment of  FIGS. 8-15  is that the release arm  108  and its associated structure is replaced by a shaped overcenter lock switch mechanism  240 , which has some of the same functionality as the release arm  108 . The overcenter lock switch mechanism  240  includes a contact surface  242  at the end of an overcenter-limiting arm  244 . The overcenter-limiting arm  244  is affixed to the lower arm  50  at a location adjacent to the second end  54  thereof. The overcenter-limiting arm  244  is affixed to the lower arm  50  by any operable approach, such as an illustrated slider pin  246  in a slot  248 . Other affixing approaches include, for example, a hinge mechanism and a slotted receiver such as discussed above and often used at the jaw end of a conventional tool. The movement of the overcenter-limiting arm  244  on the slider pin  246  or other affixing approach allows the overcenter-limiting arm  244 , and thence the contact surface  242 , to be positioned relative to the lobe  106  to allow an overcenter locking function or to prevent an overcenter locking function, depending upon the positioning. A leaf spring  250  extends between the overcenter-limiting arm  244  and the lower arm  50  to bias the overcenter-limiting arm  244  in the straight extended position.  
         [0049]      FIGS. 8-11  sequentially illustrate the operation of the tool when the overcenter-limiting arm  244  is moved to its rearward position on the slider pin  246 . In  FIG. 8 , the lower jaw  78  is separated from the workpiece and no force is applied through the handles  34  and  56 . In  FIG. 9 , force is applied through the handles  34  and  56  so that the lower handle  56  is moved counterclockwise and the lower jaw  78  just contacts the workpiece. The contact surface  242  has not contacted the lobe  106 . In  FIG. 10 , the handles  34  and  56  are squeezed together, so that a gripping load is applied to the workpiece and the lower arm  50  has moved almost, but not quite, to the overcenter position. The contact surface  242  has not contacted the lobe  106 , so that in FIG. 11  the lower arm  50  may move further to the overcenter position. At this point, there is contact between the contact surface  242  and the lobe  106 , so that the lower arm  50  may not move further. To unlock the overcenter position, the overcenter-limiting arm  244  is rotated against the force of the leaf spring  250 , clockwise in the view of  FIG. 11 , to push the lower arm  50  back through the overcenter position.  
         [0050]      FIGS. 12-15  illustrate substantially the same sequence as  FIGS. 8-11 , except that the overcenter-limiting arm  244  is moved to its forward position on the slider pin  246 . Closing the lower handle produces a progression from the fully open position of  FIG. 12 , to the contacting of the lower jaw  78  to the workpiece of  FIG. 13 , to the near-contact of the contact surface  242  to the lobe  106  of  FIG. 14 , to the contacting of the contact surface  242  to the lobe  106  of  FIG. 15 . The contact of the contact surface  242  to the lobe  106  in  FIG. 15 , before the lower control arm pivot pin  66  and reaches the overcenter position, prevents movement to the overcenter position and thereby prevents the engagement of an overcenter lock.  
         [0051]     The ability to readily switch between a tool configuration that permits an overcenter lock, as in  FIGS. 8-11 , and a tool configuration that does not permit an overcenter lock, as in  FIGS. 12-15 , is an important advantage. Some tool uses, such as the initial tightening of a fitting, are best accomplished without an overcenter lock to permit the user to move the tool quickly. Then, when the fitting is nearly tightened, the user may switch to the overcenter lock configuration to allow the final tightening to be most easily accomplished.  
         [0052]      FIGS. 16-17  illustrate some other features available for use with the present approach. These embodiments are similar to those of  FIGS. 1-15 , and the description of those embodiments is incorporated herein as appropriate with differences as noted next. In these figures, some features are not illustrated so as not to obscure the features of interest. In  FIG. 16 , the slots  40  and  42  are straight, rather than curved. Also in  FIG. 16 , the second slot  42  and the pawl  86  are not provided with teeth. Instead, a layer of a high-friction material  260  is applied to one or both of the facing surfaces of the second slot  42  (i.e., its first side  44 ) and the pawl  86  to permit them to engage each other upon tightening of the grip, instead of having teeth engage each other. The approach of  FIG. 16  using the high-friction material  260  produces an infinite degree of resolution of the engagement mechanism of the pawl  86  to the second slot  42 , although the engagement is not as secure as where teeth are used. In yet another alternative, a friction-cam lock may be used, wherein the pawl  86  or other movable element serves as a cam to engage the side of the second slot  42 .  
         [0053]     In  FIG. 17 , the upper arm  22  is provided with an upper-arm pivot hinge  270  at an intermediate position along its length. The lower arm  50  is similarly provided with a lower-arm pivot hinge  272  at an intermediate position along its length. The pivot hinges  270  and  272  allow the respective arms  22  and  50  to pivot between the illustrated open position and a folded or closed position to make the tool  20  more compact.  
         [0054]     Also shown in  FIG. 17  is at least one auxiliary tool  280  hingedly connected to one of the upper arm  22  and the lower arm  50  and rotatable in either a clockwise or counterclockwise direction according to the nature of the hinge. In the illustration, two auxiliary tools  280  are pivotably connected to the upper arm  22  by respective hinges  281 . These auxiliary tools  280  may optionally be received within a recess  282  within the arm  22  or  50 , so that they may fold to a closed position below its surface. The auxiliary tools  280  may include, for example, screwdrivers, awls, blades, or the like.  
         [0055]     A prototype of the tool  20  has been constructed with the features of  FIGS. 8-15 . The tool  20  functions smoothly to provide all of the features discussed earlier.  
         [0056]     An alternate embodiment of the tool, shown in  FIGS. 18-23 , includes two jaws  310 ,  311  pivotally connected together by a pivot pin  312  and the two handles  313 ,  314 , the handle  313  being formed integrally with the jaw  310  and the handle  314  being connected to jaw  311  by a link  315  which is attached to jaw  311  by the pivot pin  316  and to the handle  314  by a pivot pin  317 . Jaw  311  is formed with a rearward extension  311   a  and the rear end of this extension engages against the surface of a recessed portion  314   a  of handle  314  when the jaw and handles are in their opened position as shown in  FIG. 1 . When pressure is exerted on the handles to close the handles and jaws, a spring  320  connected to handle  314  and jaw  311  and the engagement of extension  311   a  with the surface  314   a  of handle  314  causes said jaw and handle to move as a unit until jaw  311  engages against an object or article between the jaws, whereupon the tension of spring  320  is overcome and handle  314  becomes disengaged from jaw extension  311   a  as indicated in  FIG. 2 .  
         [0057]     As shown in  FIG. 5 , jaw  310  and handle  313  have an opening  321   a  extending therethrough in which the handle  314  is positioned. Ribs  322  are formed in this hollow portion  321  of jaw  310  and handle  313 , said ribs being spaced apart for reception of the handle  314 . Mounted on said handle  14  at one side of the ribs  322  are means for rendering the connecting link  314  operative to increase the pressure transmitted from handle  314  to jaw  311 . As shown in  FIG. 1 , the pivotal connection  317  between link  315  and handle  314  and the pivotal connection  312  between the jaws  310 ,  311  are normally located at opposite sides of a line intersecting pivot pin  316  and the pivot pin  323  of an abutment or block  324  carried on opposite sides of the handle  314 . This abutment or block  324  is adapted to engage against the ribs  322  when the handles are presses together and the jaws  310 ,  311  engage an article positioned between them. For instance, when the jaws engage an article between them the tension of spring  320  is overcome by continuing the pressure on the handles whereupon the handle  314  will tend to pivot on the pivot pin  317 . This action on the part of handle  314  moves the block or abutment  324  into engagement with ribs  322  whereupon the handle  314  will then tend to turn on the pivot pin  323 , the block  324  at that moment being held stationary by the ribs  322 . This turning movement of handle  314  on pin  323  forces the pivotal connection  317  between the handle and link toward the line A-A with the result that jaw  311  is forced with greater pressure toward jaw  31   0 . If the object gripped between the jaws will yield sufficiently (e.g., is cut) under the pressure imposed on the handles of the tool the pivotal connection  317  between link  315  and handle  314  can be moved sufficiently far to pass beyond the line A-A intersection pivots  316  and  323 , so that the tool will be locked in their thus closed position until the handles are forcibly separated to return the pivotal connection  317  to that side of the line A-A on which it is normally located.  
         [0058]     As stated above, means are provided for regulating this action of the connecting link  315  and these means consist of a stop or screw  325  carried by the link  315  and adapted to engage an extension  311   a  of jaw  311 . By adjusting screw  325  in link  315 , the movement of pivotal center  317  with respect to the line A-A can be varied at will. That is by adjusting the screw  325  so that its end is comparatively close to the jaw extension  311   a  the movement of pivot pin  317  toward the line A-A during the closing of the handles and jaws will be rather limited whereas, if the screw  325  is so adjusted that it is spaced a maximum distance from the jaw extension  311   a,  the pivotal connection  317  will be permitted a maximum movement, which will carry it beyond the line A-A. In other words, if the stop  325  is adjusted to permit a maximum movement of the pivot pin  317  during the closing of the handles and jaws then said pin  317  will be capable of moving beyond the line A-A so as to temporarily lock the jaws in closed position. This would be the adjustment of the parts when it is desired to hold an article between the jaws without continuing the application of pressure to the tool handles. On the other hand, if it is simply desired to use the tool as a pair of tool it is only necessary to adjust stop screw  325  so that its point will come into contact with jaw extension  311   a  just before the pivot pin  317  comes into line with the pivot pins  316 ,  323 , during the closing of the jaws.  
         [0059]     The jaw faces  330  of the various embodiments discussed above each advantageously have one or more sharp cutting edges  332  oriented to cut objects disposed between the jaws  330 . The cutting edges  332  may be formed and hardened in any fashion known in the snip art. The magnified leverage force, advantageously three or more times magnification, supplied by the present invention allows the tool to cut a wider range of objects.  
         [0060]     The present invention may be carried out in other specific ways than those herein set forth without departing from the scope and essential characteristics of the invention. The present embodiments are, therefore, to be considered in all respects as illustrative and not restrictive, and all changes coming within the meaning and equivalency range of the appended claims are intended to be embraced therein.