Abstract:
An adjustment mechanism for a wire stripper that sets the initial minimum opening between cutter jaws so that the jaws close snugly around a wire, and then adjusts the opening to provide a clearance distance so that the wire is not damaged when the jaws cut through the insulation.

Description:
This application is a continuation-in-part of pending application Ser. No. 09/781,790, filed on Feb. 12, 2001. 
    
    
     BACKGROUND INFORMATION 
     1. Field of the Invention 
     The invention relates to V-notch wire strippers and particularly, to wire strippers with an adjustable stop mechanism for adjusting the wire stripper to a specific wire gauge. 
     2. Description of the Prior Art 
     Wire strippers have long been known and there are numerous variations on the basic device. The critical feature of the wire stripper is to provide the capability of adjusting a stop for the cutters so that, when the device is closed, the cutters cut through the insulation around the wire, but do not nick or damage the wire conductor. The conventional wire stripper today has two cutter bars that are movably attached to each other in an intermediate section of the bars such that when the handgrips at one end of the cutter bars are closed, the cutter jaws at the other end of the bars close around the wire to be stripped. Typically, each cutter jaw has a V-notch in the cutting area so that when the cutting jaws close toward each other, a cross-section that corresponds to the cross-section of the uninsulated wire conductor remains open and the cutting edges of the cutting jaws cut through only the insulation. The goal of all such strippers is to establish the minimum opening between the cutter jaws that will snugly embrace the stripped wire, i.e. the minimum opening that will cut through the insulation without damaging the wire itself, when the handgrips are squeezed together. 
     Since it is critical that the strippers don&#39;t close too closely around the wire, wire strippers typically have some type of adjusting mechanism or stop mechanism to set the minimum opening of the cutter jaws. The types of stop or adjusting mechanisms include cams, star-shaped wheels, and nut-and-screw slides in a groove. These mechanisms are mounted on a lower portion of one of the cutter bars and effectively stop the other cutter bar from closing too far. Many of these mechanisms require the use of a screwdriver or other tool to adjust the mechanism. This is a disadvantage, because it generally takes two hands to hold the wire stripper around a wire to adjust the stripper to the proper gauge. To have to use a screwdriver or other tool to loosen or tighten the adjusting mechanism is cumbersome and leads to inaccuracy. A shortcoming of the conventional adjusting or stop mechanisms, however, is that they do not provide for a safety clearance to ensure that the cutter jaws do not nick the conductor. Thus, determining the proper adjustment for the tool still requires guesswork on the part of the person using the tool and possibly several trials and corrections of the tool. 
     A further disadvantage of many of the conventional devices is that the adjusting mechanism “walks” when it is being set. For example, one can adjust the stripper to properly fit the wire gauge, only to have the mechanism move slightly during tightening, with the end result that the cutter jaws close too closely and then cut into the wire when the stripper grippers are squeezed closed, or are too far apart so that the jaws do not cut through the insulation properly, making it difficult to strip it from the conductor. In addition, most wire strippers have a spring mechanism that biases the cutters and grippers to an open position. The spring bias is generally desirable, because it ensures that the stripper will spring open when one&#39;s grip on the grippers is released. The disadvantage of this spring bias, however, is that it increases the difficulty of accurately adjusting the stripper, because the hand gripping the wire stripper has to counteract the biasing force of the spring during adjustment. Because of these disadvantages of conventional wire strippers, adjusting the wire stripper is typically a trial-and-error operation that requires very careful visual inspection and may require several trial cuts before the tool is properly adjusted. 
     What is needed, therefore, is a wire stripper with an adjustable stop mechanism that will allow the operator of the tool to quickly and easily change or adjust the setting of the stripper, with excellent accuracy and repeatability. What is further needed is such a device that will automatically provide clearance for the uninsulated conductor, without the need to use additional tools or to know the wire gauge. What is yet further needed is such a device that provides a means of controlling a biasing spring to achieve the desired bias function and to quickly and easily convert the bias function of the spring to a hold function that holds the current position of the stripper. 
     SUMMARY OF THE INVENTION 
     It is an object of the present invention to provide a V-notch wire stripper that has an accurate and easily adjustable stop mechanism for setting the minimum proximity of the cutter jaws. The term “minimum proximity” or also “minimum opening” refers to the size of the opening in the cutter jaws that fits snugly around the bare wire when the stripper is closed. It is a further object of the invention to provide such a wire stripper that does not require the use of an additional tool such as a screwdriver to adjust the minimum proximity of the cutter jaws. It is a yet further object to provide such a wire stripper that automatically provides a safety clearance for the uninsulated wire. It is a still yet further object to provide such a stripper that has a biasing spring that, in a first position, biases the cutter bars open, but can be easily placed into a second position that helps to hold the then current opening of the stripper. 
     The objects are achieved by providing a wire stripper that has an adjustable stop mechanism that includes a cam and a slider mounted in a groove on one of the cutter bars. The slider has a tab on its upper end and another tab on its lower end. These tabs fit within the groove and serve as guides, allowing the slider to move along a section of the cutter bar. A detent, in some embodiments a hemispherical protrusion, is provided on the upper face of the slider. The cam also has a lever along one side which can be used to move the cam into a HOLD position, a CUT position, or into a RELEASE position. When the cam lever is pushed to the RELEASE position, the slider can be moved along the groove; when pushed to the HOLD position, the detente applies sufficient force against the slider to hold the slider in position in the groove; and when pushed to the CUT position, the position of the cam is adapted such to force the cutter bars apart slightly, so that the cutter bars cut through the insulation on the wire, yet provide a security clearance between the cutter edges and the conductor. 
     To adjust the stripper for a particular wire gauge, the operator first checks that the cam is in the RELEASE position. The operator then places a piece of uninsulated wire into the V-notch area of the cutter jaws and brings the cutter jaws together around the wire, such that the jaws close snugly around the wire, but without cutting into it. If uninsulated wire is not available, the operator can, of course, place a piece of insulated wire in the stripper and gently squeeze the grippers until he or she senses that the cutter jaws have cut through the insulation and just touched the wire. Once the cutter jaws have been brought into light contact with bare wire, the operator then slides the slider in the groove with the other hand until the edge of the slider touches the edge of the other cutter bar. At this point, the operator pushes the cam lever all the way to an inner stop that forces the cutter bars to open slightly more, thereby automatically providing the correct clearance for allowing the cutters to cut through the insulation without marking or damaging the conductor. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     FIG. 1 is a perspective view of the front side of the V-notch wire stripper according to the Preferred Embodiment of the invention. 
     FIG. 2 is an exploded view of the individual components of the stop mechanism of the Preferred Embodiment of the invention, including the cam, the slider with the detent, the groove, and the fastener. 
     FIG. 3 is a perspective view of the front side of the V-notch wire stripper according to the alternative embodiment of the invention. 
     FIG. 4 is an exploded view of the individual components of the stop mechanism of the Preferred Embodiment of the invention, including the cam, the slider with the detent, the groove, and the fastener. 
     FIG. 5 is a perspective view of the rear side of the V-notch wire stripper according to the invention, with the biasing spring in the BIAS position. 
     FIG. 6 is a perspective view of the rear side of the V-notch wire stripper according to the invention, with the biasing spring in the HOLD position. 
     FIG. 7A shows a top view of the biasing spring according to the invention. 
     FIG. 7B shows a side view of the biasing spring according to the invention. 
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
     FIG. 1 shows the Preferred Embodiment of a V-notch wire stripper  1  according to the present invention. As can be seen, the wire stripper  1  comprises primarily a first cutter bar  2 , a second cutter bar  3 , and a stop mechanism  20 . Each cutter bar  2 ,  3  has a cutter jaw at a respective upper portion of the bars  2 ,  3 , designated respectively as  2 A and  3 A, and each jaw  2 A,  3 A is provided with a V-notch. The two cutter bars  2 ,  3  are pivotably attached to each other by means of a fastener  4 . The lower portions of the two cutter bars  2 ,  3  extend into grippers, i.e., the first cutter bar  2  extends into a first gripper  5  and the second cutter bar  3  into a second gripper  6 . A groove  7  is cut into the second cutter bar  3  and the stop mechanism  20  is seated in the groove  7 . As shown in FIG. 1, the stop mechanism  20  has been slid in the groove  7  toward the jaw end of the cutter bar  3  until a limiting edge  20 A contacts an edge of the first cutter bar  2  while the wire stripper  1  closes around the cross-section of an uninsulated section of wire  8 , shown with dashed lines. 
     FIG. 2 is an exploded view of the individual components of the stop mechanism  20 , which includes a cam plate  22  with a cam edge  22 A and a slider  23 . The slider  23  has a first end proximal to the jaw end of the wire stripper  1  and a second end proximal to the gripper end. A tab  23 A is provided at each end of the slider  23 . FIG. 2 shows only the tab  23 A at the end proximal to the jaw end of the wire stripper  1 . The slider  23  has an outer edge with an outer stop  23 C and an inner edge with an inner stop  23 D. The outer stop  23 C and the inner stop  23 D serve to limit the movement of the cam plate  22 . A detent  23 B, for example, a raised hemispherical protrusion, is provided on an upper face of the slider  23 . A slider through-bore  23 E and a cam through-bore  22 E are provided respectively on the slider  23  and on the cam plate  22  such that the two through-bores are aligned one above the other. A lever  22 B is provided along an outer edge of the cam plate  22  for the purpose of the adjusting the position of the cam plate  22 . 
     To assemble the stop mechanism  20  in the wire stripper  1 , the slider  23  and the cam plate  22  are arranged on an upper face  3 B of the second cutter bar  3 , over the groove  7 , and aligned so that the respective slider and cam through-bores  23 E and  22 E are aligned with a concentric hole  24 E in a fastener plate  24  that is positioned on the lower face of the cutter bar  3 . A fastener  21  is inserted through the respective bores  22 E,  23 E, and  24 E and fastened to the fastener plate  24 , so as to hold the slider  23  and the cam plate  22  together in the groove  7 . When the cam lever  22 B is pushed against the outer stop  23 C, the cam plate  22  and the slider  23  have a certain amount of play in the groove, allowing the stop mechanism  20  to slide in the groove  7 . By sliding the cam plate  22  toward the inner stop  23 D, the cam plate  22  slides across the detente  23 B, thereby applying sufficient force to the cam plate  22  and the slider  23  to hold the stop mechanism  20  in a desired position with respect to the cutter jaws  2 A,  3 A. 
     Operation of the wire stripper  1  is as follows: 
     Hold the wire stripper  1  with one hand; and with the thumb of the same hand, push the cam lever  22 B to the outer edge of the wire stripper  1 . Slide the slider  23  in the groove  7  so that the wire stripper  1  can be opened sufficiently to receive a piece of wire to be stripped. 
     Insert a piece of uninsulated wire between the cutter jaws  2 A,  2 B and close the jaws around the wire. In the alternative, insert a piece of insulated wire, and squeeze the grippers gently until the cutter jaws just contact the bare wire. 
     Slide the slider  23  up toward the jaw end of the wire stripper  1  until the limiting edge  20 A hits the opposite cutter bar  2 . 
     Push the cam lever  22 B toward the inner edge of the cutter bar  3 . As the cam plate  22 A slides across the detente  23 B more force is required to move the cam lever  22 B, as a result of the force applied by the detente  23 B. Moving the cam plate  22  to the limit at the inner stop  23 D rotates the cam edge  22 A slightly, thereby forcing the cutter jaws  2 A,  3 A slightly farther apart. This provides the correct clearance in the V-notch wire stripper  1  that will allow the stripper  1  to cut through the insulation when the jaws  2 A,  3 A close over an insulated section of the wire, yet not mark or damage the wire conductor. 
     FIGS. 3 and 4 illustrate a wire stripper  100  that is an alternative embodiment of the wire stripper  1 . Elements of this wire stripper  100  that are identical to elements of the wire stripper  1  are designated with the same reference numerals. As shown in FIGS. 3 and 4, the stop mechanism  10  of the alternative embodiment comprises a thumb screw  11  with a folding wire tab  11 A, a cam plate  12 , a slider  13 , and a T-nut  14 . The T-nut  14  has a threaded bore  14 A and an upper contour that fits against the groove  7  on the lower face  3 C of the second cutter bar  3 . A cam plate through-bore  12 E and a slider through-bore  13 E are provided respectively on the cam plate  12  and the slider  13  such that they are axially aligned with each other. A detente  13 B is provided on the slider  13  and a corresponding detente-seat  12 A is provided on the cam plate  12 . In this alternative embodiment, the detente seat  12 A is a throughbore sized to receive the detente, although it is also possible to provide an indentation rather than a bore to seat the detente. The detent seat  12 A is constructed to slide over and snap into position over the detent  13 B. A lever  12 B is provided along an outer edge of the cam plate  12 . 
     The manner of using this wire stripper  100  is similar to that of the wire stripper  1 , the difference being in the means of securing the cam plate  12 . To adjust the opening of the cutter bars  2 A,  3 A, the steps are as follows: 
     Hold the wire stripper  100  with one hand and with the other hand fold up the wire tab  11 A of the thumb screw  11 , turn the tab  11 A with fingers to loosen the thumb screw  11  (just enough to allow the stop mechanism  10  to slide in the groove  7 ), and move the cam lever  12 B to the left until the cam  12  hits an outer stop  13 C on the slider  13 . 
     Place a section of uninsulated wire into the V-notch area of the cutter bars  2 A,  3 A and close the grippers  5 ,  6  until light contact is made between the wire and the two V-notches in the jaws  2 A,  3 A. 
     Slide the stop mechanism  10  on the second cutter bar  3  forward until it firmly contacts the edge of the first cutter bar  2 . 
     Tighten the thumb screw  11  by turning the wire tab  11 A and then fold the tab  11 A down, so that it does not interfere with operation of the stripper  100 . 
     Move the cam lever  12 B to the right until the cam  12  stops against the inner stop  13 D and the detente seat  12 A snaps into place over the detent  13 B. The cam  12  is constructed so that, in this position, it will slightly increase the minimum opening between the respective V-notch areas on the jaws  2 A,  3 A of the cutter bars  2 ,  3  when the stripper  100  is closed. This automatically provides the correct clearance in the V-notch wire stripper  100  that will allow the stripper  100  to cut through the insulation when the jaws  2 A,  3 A close over an insulated section of the wire, yet not mark or damage the wire conductor. 
     FIGS. 5 and 6 illustrate a BIAS and a HOLD feature, respectively, provided by a biasing spring  15  that is adaptable to both the Preferred Embodiment and the alternative embodiment of the wire strippers  1 ,  100 . For simplicity&#39;s sake, reference is made hereinafter to the Preferred Embodiment of the wire stripper  1  in the description of the biasing spring  15 , though it is to be understood that use of the biasing spring  15  is just as applicable to the alternative embodiment of the wire stripper  100 . FIGS. 7A and 7B show a top view and a side view, respectively, of the spring  15 . 
     As shown in FIGS. 5 and 6, the wire-type spring  15  is mounted on the first cutter bar  2  by means of a rivet  15 B that holds the spring  15  in place on the cutter bar  2  and a retaining hole  15 A into which a fixed end  15 A′ is inserted and held. When the biasing spring  15  is in the BIAS position shown in FIG. 5, it exerts a force against the side edge of the cutter bar  3 . This force will automatically force the stripper  1  to open when the operator loosens his or her grip on the tool. By flipping an operating end  15 C of the spring  15  up over the upper surface of the second cutter bar  3 , the spring  15  no longer forces the stripper  1  open when one or the other gripper  5 ,  6  is released, but holds the then current position of the stripper  1 . This HOLD function is desirable when setting the stop mechanism  20  and is achieved by the force of friction between the two cutter bars  2 ,  3  that results from the force the operating end of the spring  15  exerts on the two cutting bars  2 ,  3 . By simply opening the grippers  5 ,  6  wide, the operative end  15 C of the spring  15  automatically drops down into its BIAS position on cutter bar  2 , shown in FIG. 5, where it now exerts a force on the cutter bar  3  to bias the stripper  1  to an open position. 
     The embodiments mentioned herein are merely illustrative of the present invention. It should be understood that variations in construction of the present invention may be contemplated in view of the following claims without straying from the intended scope and field of the invention herein disclosed.