Patent Publication Number: US-7913400-B2

Title: Compact bolt cutter with improved mechanical advantage

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
     This application claims the benefit of provisional application Ser. No. 60/879,485, filed 2007 Jan. 9 by the present inventor. 
    
    
     FEDERALLY SPONSORED RESEARCH 
     Not Applicable 
     SEQUENCE LISTING OR PROGRAM 
     Not Applicable 
     BACKGROUND 
     1. Field of Invention 
     This invention relates in general to bolt cutters but may also apply to other devices for cutting or punching. 
     2. Prior Art 
     A commonly used conventional device for cutting bolts, locks, and reinforcement bar is referred to as a bolt cutter. The standard bolt cutter is generally made up of two long handles connected to a pair of opposing jaws that can be manually separated or brought together by movement of the handles. The long handles enable the user to produce force at the jaws for cutting, usually smaller sized bolts. This embodiment relates to a bolt cutter, type cutting tool, specifically with an improved closing mechanism. 
     Originally bolt cutters were manufactured with relatively long handles to help the user generate the desired cutting force, as with U.S. Pat. No. 3,949,473 to Blanc (1976). However, many consumers are still unable to generate enough force to produce the desired cut. Thereafter, several other cutting tools have been proposed U.S. Pat. No. 5,862,597 to Juros (1999) discloses a cutter with an increased handle arc range that only slightly increased the mechanical advantage upon closing. U.S. Pat. No. 5,014,432 to Putsch (1991) discloses a handle arrangement that crosses over without joint increasing the cutting output, but still requiring the user to generate a substantial amount of force. 
     U.S. Pat. No. 5,898,998 to Deville (1999) discloses a cutting tool with emphasis on decreasing the thickness of the support members, producing a lighter tool but with still the cutting difficulties of previous cutters. 
     One of the disadvantages to the existing devices is that the handles have to be made extremely long and it is still difficult for the user to be able to produce sufficient cutting force. It is an object of the present invention to increase by simple means the cutting power produced while closing the more compact handles. 
     Also, existing devices are limited in their use to the force that can be applied directly by the user of the device. And so the amount of force generated for cutting is limited by the physical strength of the user. Further, the state of the art bolt cutters are heavy and cumbersome to use. 
     Accordingly, it is an object of the present invention to provide an improved bolt cutter with greater cutting force utilizing a substantially enhanced mechanical advantage thereto. So that cutting of relatively large hard work-pieces, such as bolts or reinforcing bars of steel can be effected with relative ease. 
     Still another object of the present invention is to provide a bolt cutter, that can be manufactured with a lighter, smaller more compact construction. 
     SUMMARY 
     The foregoing and other objects, features and advantages of the present invention can be realized by providing a cutting or punching apparatus having at one end a set of jaws and at the other end a relatively shorter length handles that are connected by a means for providing a mechanical advantage. In the disclosed embodiment herein this means includes a threaded rod that can be turned to close the handles and similarly close the jaws. 
    
    
     
       DRAWINGS 
       Figures 
       Numerous other objects, features and advantages of the present invention should now become apparent upon a reading of the following detailed description taken in conjunction with the accompanying drawings, in which: 
         FIG. 1  is a first view of the device of the present invention shown in its open position. 
         FIG. 1A  illustrates an alternate embodiment for the cutting end of the device. 
         FIG. 1B  shows a further alternate embodiment at the distal end of the device for providing a punching action. 
         FIG. 2  is a view similar to that shown in  FIG. 1  but with the jaws closed. 
         FIG. 3  is a view similar to that shown in  FIG. 2  and illustrating the applied force. 
         FIG. 4A  and  FIG. 4B  show alternate embodiments at the proximal end of the device supplying the rotational force. 
     
    
    
     REFERENCE NUMERALS 
     
         
           10  jaws 
           10 A,  10 B separate jaws 
           12 A,  12 B handles 
           13 A threaded hole  13 B through-hole 
           14 ,  14 A threaded rod 
           15  arrows 
           16  rotational handle 
           18  yoke 
           20  pin 
           25  holder 
           28  hex head 
           29  central drive engagement 
           30  ratchet handle 
       
    
     DETAILED DESCRIPTION 
     FIGS.  1 , ( 1 A &amp;  1 B),  2 ,  3  and  4 A and  4 B 
     Reference is now made to the drawings illustrating one possible embodiment of the cutting tool of the present invention. As indicated previously, this tool can be used for cutting such as the cutting of bolts or can be used for cutting cables, locks, reinforcement bar or can even be used for a punching operation. The device is basically comprised of a set of jaws  10  including separate jaws  10 A and  10 B. Each of these jaws has a cutting blade and is supported for pivotal operation from the handles  12 A and  12 B. The basic cutting blades and handles  12 A and  12 B are like that found in existing instruments except that handles  12 A and  12 B are quite short in comparison to the conventional bolt cutter. When handles  12 A and  12 B are in a more open position such as shown in  FIG. 1 , this corresponds to an open position of cutting jaws  10 . 
     At the base of handles  12 A and  12 B there is provided a tightening, lead or threaded rod  14  that functions similar to a jack for drawing handles  12 A and  12 B together such as illustrated by the arrows  15  in  FIG. 3 . For this purpose the end of  12 A may be provided with a threaded hole  13 A for receiving threaded rod  14 . The free end of handle  12 B supports the other end of threaded rod  14  by through-hole  13 B. I presently contemplate that a rotational handle  16  be used to rotate threaded rod  14 , however, in other embodiments, as in  FIG. 4B  threaded rod  14 A is rotated by a centrally located ratchet handle  30 . The rotation of threaded rod  14  in turn causes handles  12 A and  12 B to move either together or apart. The threads on threaded rod  14  may be either left or right hand threads. Further, the number of threads per inch on rod  14  can also be altered to produce the desired cutting force. 
     Rotatable handle  16  is secured at the yoke  18  such as by means of pin  20  which may be a cotter pin. The combination of handle  16  and threaded rod  14  associated with handles  12 A and  12 B provides a substantial mechanical advantage in closing jaws  10  such as from the position shown in  FIG. 1  toward the position shown in  FIG. 2 . 
     The drawings also show a holder  25  that may be screwed into one of the handles such as into illustrated handle  12 A. Holder  25  is preferably engageable on either side of handle  12 A or may be engageable with handle  12 B depending upon whether the instrument is being held by a left or right handed person. Holder  25  assists in holding and stabilizing the instrument during operation. 
     As indicated previously, rotation handle  16  may be removed by removing cotter pin  20 . This enables one to operate threaded rod  14  in other manners. For example, there may be provided a hex head  28  and if yoke  18  is removed then hex head  28  can be used with a socket, wrench or ratchet to rotate threaded rod  14 A. Also, at either end of threaded rod  14  or  14 A there may be provided a means for receiving a drive drill or other motorized drive apparatus for driving threaded rod  14  under operator control.  FIG. 4A  also shows an alternate location for a drive engagement  29 . The threads on threaded rod  14 A are comprised of opposing left and right threads, enabling the centrally located attachment to draw handles  12 A and  12 B together. 
     The means provided which includes either threaded rod  14  or  14 A for closing handles  12 A and  12 B of the instrument provides a substantial mechanical advantage over an operator manually operating handles  12 A and  12 B. This can provide at least one order of magnitude of force greater than is able to be applied by merely manually closing the handles directly. This arrangement, by shortening the length of handles  12 A and  12 B, also provides a far more compact and easily operable bolt cutting arrangement. 
     As indicated previously, the distal end of the instrument may also be constructed in different manners. Refer to  FIG. 1A  and  FIG. 1B  for illustrations of different cutting arrangements.  FIG. 1A  represents arcuate blades for cutting cables rather than the straight surface as shown in  FIG. 1 , and  FIG. 1B  refers to a punching arrangement that may be comprised of a male and a female member. This may be used for punching holes in, for example, steel plate. In either  FIG. 1A  or  FIG. 1B  the mechanisms are closed in a similar manner to that illustrated in  FIGS. 1-4 . 
     Having now described a limited number of embodiments of the present invention, it should be apparent that numerous other embodiments and modifications thereof are contemplated as falling within the scope of the present invention. For example, mention has been made of the use of a motorized drive for threaded rod  14  or  14 A. This motorized drive may be provided at either end of threaded rod  14  or the center of threaded rod  14 A. Also, other forms of drive members may be engaged with threaded rod  14  or  14 A in addition to the use of hex head  28 . 
     Operation 
     FIGS.  1 ,  2 ,  3  and  4 A and  4 B 
     The bolt cutter comprises left and right cutting jaws  10  that are closed by handles  12 A and  12 B. As handles  12 A and  12 B are separated, the jaws open to allow the material to be cut to enter. As handles  12 A and  12 B are closed utilizing threaded rod  14  or  14 A to draw them closed, the cutting edges of jaws  10  close and cut the inserted material. The improved mechanical advantage provided by threaded rod  14  or  14 A allows any user to generate the needed cutting force. Thus, the tool is not limited by the physical strength of the user. The substantially enhanced mechanical advantage allows for the cutting or punching of relatively large hard workpieces, such as bolts or reinforcing bars of steel with relative ease. 
     Another advantage of the embodiment is a bolt cutter that is less cumbersome and can be manufactured with a much more compact construction than the traditional bolt cutters. 
     Alternative Embodiment 
     FIG.  4   
     Additional embodiments are shown in  FIG. 4A  and  FIG. 4B .  FIG. 4A  shows a centrally located drive engagement. In  FIG. 4B  threaded rod  14 A is shown with centrally located ratchet handle  30 , for this embodiment threaded rod  14 A would have opposing right and left hand threads on either side of centrally located ratchet handle  30  to produce the desired closing of handles  12 A and  12 B. 
     Advantages 
     From the description above, a number of advantages of some embodiments of my compact bolt cutter become evident:
         (a) The threaded rod design provides a substantial mechanical advantage when closing the handles.   (b) The enhanced mechanical advantage allows for much shorter handles than a traditional bolt cutter.   (c) The cutting force generated by the tool is not limited by the physical strength of the user.   (d) It is lighter, less cumbersome and can be manufactured with a more compact construction.   (e) The balance and physical safety of the operator is not jeopardized using this new and extremely controlled cutter.   (f) This device eliminates the need for multiple persons to produce the necessary cutting force.   (g) It is a valuable tool for enclosed or hazardous locations.       

     CONCLUSION, RAMIFICATIONS, AND SCOPE 
     Accordingly, the reader will see that the bolt cutter of the various embodiments is much less cumbersome and easier to use than any of the traditional bolt cutters. The cutting force generated by the enhanced mechanical advantage makes it more widely usable, as it is not limited by the physical strength of the user. The relative ease and speed in which it cuts makes it a valuable tool to commercial institutions, fire and rescue teams. Its simplistic design can be easily manufactured and adds a new dimension to the bolt cutting market. 
     Although the description above contains many specificities, these should not be construed as limiting the scope of the embodiment but as merely providing illustrations of some of the presently preferred embodiments. 
     Thus the scope of the embodiment should be determined by the appended claims and their legal equivalents, rather than by the examples given.