Abstract:
A cutting tool capable of cutting work pieces which are thicker than what comparably-sized conventional cutting tools are capable of cutting has a jaw with a cutting edge which does not completely abut or overlap over the full length of an opposing edge of a second jaw when the cutting tool is in its closed position. A resulting gap between the opposing edges varies from a maximum at the free end of the cutting edges to zero at a portion of the opposing edges where the edges abut one another. The cutting tool successively notches a work piece, and as the notch deepens, the work piece is advanced toward the abutting portion of the cutting edge and the opposing edge until it is finally severed. The jaws may be operated manually by hand levers or driven by hydraulic, pneumatic or electrical drive mechanisms.

Description:
BACKGROUND OF THE INVENTION 
   The present invention relates generally to cutting tools, and, more particularly, to cutting tools used for cutting solid, high strength materials such as metals. 
   Cutting tools are well-known. Conventional cutting tools generally include a pair of opposing jaws with sharpened edges which pivot such that the jaws can be operated to be separated and brought together, often using levers to actuate the jaws, forcing the sharpened edges against the material to be cut. The cutting stroke generally begins with the jaws being separated as the levers are moved apart, the material to be cut is inserted between the opened jaws, and the jaws are forced together as the levers are moved together, creating a force which exceeds the strength of the material within the jaws, thus cutting the material. Typically, the jaws come together in either a scissors shear cutting action, where the jaw edges overlap at the end of the cutting stroke or in a pliers cutting action, where the jaw edges abut one another at the end of the cutting stroke. The force imposed on the material for a given lever force increases as either the length of the levers (as measured from the point of application of force to the levers to the lever pivot point) increases or the distance between the pivot point and the work piece decreases. 
   A deficiency of the prior art is that conventional shear type cutting tools are not suitable for cutting relatively thick materials. When cutting very thin materials, shear type tools work well because the work piece can be entered and advanced successively with limited opening of the blades. However, as the thickness of the work piece increases, the cutting action becomes less efficient. With shear type cutting tools, twisting forces are developed by the non-aligned cutting members. As the thickness of the work piece increases, the twisting forces tend also to increase. Twisting forces are undesirable in that they tend to cause the blades to misalign (in turn tending to further increase the twisting forces), decreasing the cutting force applied to the work piece and potentially damaging the cutting edges. 
   Typically, tools with abutting jaws, such as pliers or bolt cutters, are used to cut relatively thick materials such as wire, bolts and rods. The abutting, in-line cutting action of these tools, where the cutting forces are in alignment, eliminates or minimizes the twisting forces characteristic of the shear type devices. However, conventional abutting jaw type devices do suffer from the deficiency that the jaws must be moved from their abutting closed position to an open position such that the jaws are spread sufficiently to accommodate the full thickness of the work piece, which typically requires substantial movement of the actuating levers. Furthermore, conventional abutting jaw devices are not well-suited for the work piece to be successively advanced into the jaws with limited blade movement. 
   BRIEF SUMMARY OF THE INVENTION 
   The invention is directed to a cutting tool comprising a first jaw having first and second ends and first and second edges extending between the first and second ends. At least a portion of the first edge of the first jaw forms a cutting edge between the first and the second ends. The cutting tool further comprises a second jaw having first and second ends and first and second edges extending between the first and second ends. At least a portion of the first edge of the second jaw faces the first edge of the first jaw. The first and second jaws are pivotally connected together such that the first edge of the first jaw and the first edge of the second jaw oppose one another and pivot between a closed and an open position. In the closed position, an angled gap is formed between the cutting edge of the first jaw and the facing portion of the first edge of the second jaw. The gap increases in size from zero at one end of the first edges to a finite value at an opposite end of the first edges. 

   
     BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWINGS 
     The foregoing summary, as well as the following detailed description of preferred embodiments of the invention, will be better understood when read in conjunction with the appended drawings. For the purpose of illustrating the invention, there is shown in the drawings embodiments which are presently preferred. It should be understood, however, that the invention is not limited to the precise arrangements and instrumentalities shown. In the drawings: 
       FIG. 1  is a right side elevational view of a cutting tool of the present invention, illustrating the jaws being opened and a work piece being inserted within the jaws; 
       FIG. 2  is a right side elevational view of the cutting tool of  FIG. 1 , illustrating the jaws being closed down upon a work piece; 
       FIG. 3  is a right side elevational view of the cutting tool of  FIG. 1 , illustrating the jaws being opened and the work piece being advanced within the jaws after an initial cutting stroke has been made; 
       FIG. 4  is a right side elevational view of the cutting tool of  FIG. 1 , illustrating the jaws being closed upon the work piece in a second cutting stroke; 
       FIG. 5  is a right side elevational view of the cutting tool of  FIG. 1 , illustrating jaws being opened and the work piece being advanced for a final cutting stroke; 
       FIG. 6  is a right side elevational view of the cutting tool of  FIG. 1 , illustrating the jaws being closed down upon the work piece in a final cutting stroke, severing the work piece; 
       FIG. 7  is a front end view of the cutting tool of  FIG. 1 ; 
       FIG. 8  is a right side elevational view of a second embodiment of the present invention, wherein the jaws of the cutting tool have cutting edges with non-linear profiles; 
       FIG. 9  is a right side elevational view of a third embodiment of the present invention, wherein the jaws are meshing gear-type surfaces used to maintain alignment of the jaws; 
       FIG. 10  is a right side elevational view of a fourth embodiment of the present invention, wherein the jaws of the cutting tool are opened and closed with hand levers, illustrating the jaws in their open position; 
       FIG. 11  is a right side elevational view of the hand tool of  FIG. 10 , illustrating the jaws in their closed position; 
       FIG. 12  is a left side elevational view of a fifth embodiment of the present invention, wherein the jaws of the cutting tool are operated by a hand-held motorized device and the jaws execute one cutting stroke per revolution of a bevel gear, with the jaws shown in a closed position; 
       FIG. 13  is the hand tool of  FIG. 12 , with the jaws shown in an open position; 
       FIG. 14  is a left side elevational view of a sixth embodiment of the present invention, wherein jaws of the cutting tool are operated by a hand-held motorized device and the jaws execute two cutting strokes per revolution of a bevel gear, with the jaws shown in a closed position; 
       FIG. 15  is the hand tool of  FIG. 14 , with the jaws shown in a first open position; 
       FIG. 16  is the hand tool of  FIG. 14 , with the jaws shown in a second open position; 
       FIG. 17  is a left side elevational view of a seventh embodiment of the present invention, wherein one jaw is provided with a cutting edge and the second jaw is provided with an opposing cutting anvil; and, 
       FIG. 18  is a front end view of the hand tool of  FIG. 17 . 
   

   DETAILED DESCRIPTION OF THE INVENTION 
   A first preferred embodiment cutting tool jaw set of the present invention is shown in  FIGS. 1–7  and is indicated generally at  10 . The cutting tool is comprised of a first  12  and a second  14  jaw. The first jaw  12  has opposing, first  16  and second  18  ends, a first, outer edge  20  and a second inner edge  22  extending between the ends  16 ,  18 . The first jaw  12  includes a pivot point  24  intermediate the first  16  and second  18  ends and the first  20  and second  22  edges. At least a portion of the first edge  20  of the first jaw  12  intermediate the pivot point  24  and the first end  16  is sharpened to form a cutting edge  26 . The first jaw  12  also includes a through hole  28  proximate the second end  18 . Similarly, the second jaw  14  also has opposing first  30  and second  32  ends, a first, outer edge  34  and second, inner edge  36  extending between the ends  30 ,  32 . The second jaw  14  also includes a pivot point  38  intermediate the first  30  and second  32  ends and the first  34  and second  36  edges. At least a portion of the first edge  34  of the second jaw  14  intermediate the pivot point  38  and the first end  30  is sharpened to form a cutting edge  40 . The second jaw  14  also includes a through hole  42  proximate the second end  32 . 
   The first  12  and second  14  jaws are operably connected by a first assembly plate  44  and a second assembly plate  46 . A first assembly hole  48  extends through the first assembly plate  44 , through the first jaw  12  at pivot point  24  and through the second assembly plate  46 . A second assembly hole  50  extends through the first assembly plate  44 , through the second jaw  14  at pivot point  38  and through the second assembly plate  46 . Fasteners  52 ,  54 , for example bolts with nuts or rivets, extend through the assembly holes  48 ,  50 . Washers  53  and  55  underlie fasteners  52  and  54 . 
   At the end of the cutting edges  26  and  40  proximate the pivot points  24  and  38 , the edges abut together when the first  12  and second  14  jaws are in their closed position, forming an abutment section  56  (see  FIG. 2 ). From this abutment section  56 , the cutting edges  26  and  40  are angled away from one another, thus forming a gap  58 , which increases in size from zero at the end of the abutting section  56  proximate to the first ends  16  and  30 , to some finite value at the first ends  16  and  30 . Note that at the opposite end of the abutment section  56 , proximate the second ends  18  and  32 , each jaw  12  and  14  has an opposing semicircular cut-out  60  and  62 , which facilitate the jaws  12  and  14  to fully align with one another longitudinally during operation, by virtue of a fulcrum pin  63  which is inserted between the cut-outs  60  and  62 . The fulcrum pin  63  is captured on its ends by the assembly plates  44  and  46 . Another method for maintaining alignment of the first and second jaws  12 ,  14  would be to form meshing gear type surfaces on mating portions of the jaws  12  and  14 . This method is described later herein under the discussion of the third embodiment of the invention. 
   The preferred material of construction for the cutting tool  10  is hardened tool steel. Other materials, for example, stainless steel or other combinations of materials, for example hardened tool steel for the jaws  12 ,  14  and polypropylene or ABS plastic for the plates  44 ,  46 , could be substituted. 
   From this disclosure, it would be obvious to one skilled in the art to modify the arrangement of the jaws  12  and  14  as shown. For example, the jaws  12  and  14  could be modified to make the cutting edges  26  and  40  proportionally smaller or larger relative to other features of the jaws  12 ,  14 . The size of the gap  58  or the length of the abutment section  56  could be increased or decreased, either in absolute terms or in proportion to the other features of the jaws  12 ,  14 . 
   In operation, actuating forces are applied to the second ends  18  and  32  of the first  12  and second  14  jaws, respectively. The forces are preferably applied by force carrying members (not shown) connected to the first  12  and second  14  jaws at the through holes  28  and  42 . When the forces are applied as indicated by the arrows in  FIG. 1 , the jaws  12  and  14  tend to pivot away from one another at their first ends  16  and  30 , thus opening the gap  58  and separating the jaws  12 ,  14  from one another at the abutment section  56 . A work piece  64  of a size suitable to fit within the gap  58  may then be inserted between the jaws  12  and  14 , within the gap  58 . As the directions of the applied forces are reversed, as indicated by the arrows in  FIG. 2 , the jaws  12  and  14  tend to pivot toward one another at their first ends  16  and  30 . The jaws  12  and  14  continue to close together, resulting in a cutting stroke, up to the point where the jaws  12  and  14  fully abut one another at the abutment section  56 . During this cutting stroke, the work piece  64  is notched. Note that the cutting tool  10  may be rotated about a work piece which is generally circular in cross-section, as is the work piece  64  illustrated in the Figs., scoring the work piece surface at multiple points about the circumference. As indicated by  FIGS. 1–6 , this cycle of alternatively opening the jaws  12  and  14 , advancing the work piece  64  toward the abutment section  56 , and closing the jaws  12  and  14  in a cutting stroke, incrementally notches the work piece  64  until it fully advances into the abutment section  56  and is completely severed. It should be noted that this incremental notching of the work piece  64  allows a relatively large work piece  64  to be severed by the cutting tool  10 . 
   This incremental cutting action, in conjunction with the jaw gap  58 , does not require the jaw ends  16  and  30  to move through an arc equal to the work piece  64  thickness as is required of conventional devices. Hence, the jaws  12  and  14  need be actuated only by that amount sufficient to score the work piece  64 , such that the work piece  64  may be successively notched and advanced into the jaws  12  and  14 . Because no large movement of the jaws  12  and  14  is required, the jaws  12  and  14  may be designed for optimal weight, strength and simplicity (note that the fulcrum pin  63 , which is highly desirable for its low cost and simplicity, works best in jaw designs with limited motion). Equally important, a device which actuates the jaws  12  and  14  can be simplified and optimized for maximum actuating force over a limited range of jaw  12 ,  14  motion. 
   From this disclosure, it would be obvious to one skilled in the art to modify the profile of the cutting edges  26  and  40  to tailor the cutting tool  10  for different materials and applications.  FIG. 8  illustrates a second embodiment of the cutting tool  10 ′ where the profile of the cutting edges  26 ′ and  40 ′ is nonlinear, with the profile assuming a relatively steep angle at ends  16  and  30 . The resulting wider gap  58 ′ and more steeply angled profile would be best suited for relatively soft materials, (such as copper, wood or mild steels) which can be cut with relatively few advances. In contrast, a less steeply angled profile of cutting edges  26 ′ and  40 ′ combined with longer jaws  12 ′ and  14 ′ would be better suited for harder materials, such as hardened steels, which require numerous cuts and advances, and greater cutting forces. The profile could be further tailored for use with work pieces composed of a combination of materials (for example an Aluminum Conductor Steel Reinforced (ACSR) cable used in power transmission). Furthermore, serrations could be added to the cutting edges  26 ′ and  40 ′ to minimize slippage of the work piece  64 . 
   From this disclosure, it would be further obvious to one skilled in the art that the jaws  12  and  14  may be actuated to rotate relative to one another by a variety of means. For example, rotation may be effected by manually-operated levers. Or the jaws  12  and  14  could be caused to rotate by an electrically, hydraulically or pneumatically driven motive force connected to the jaws  12  and  14  either directly or through a mechanical drive system. 
   As indicated above, the fulcrum pin  63  is one preferred method of maintaining alignment of the first and second jaws  12  and  14 . As illustrated in  FIG. 9 , a third embodiment of the invention  10 ″ uses another method for maintaining alignment of the first and second jaws  12 ″,  14 ″, specifically, meshing gear type surfaces  60 ″ and  62 ″ on mating portions of the jaws  12 ″ and  14 ″. Assembly plate  44 ″ is omitted from  FIG. 9  to improve clarity of illustration of the meshing surfaces  60 ″ and  62 ″. 
     FIGS. 10 and 11  illustrate a fourth preferred embodiment of the present invention. A hand tool  110  is comprised of the cutting tool  10  of the first embodiment combined with manual means for applying actuating forces to the jaws  12  and  14 . In this embodiment, first and second levers  166 ,  168  are connected to the jaws  12  and  14  and to each other. The first lever  166  includes a first end  170  and a second end  172 . A handle portion  174  is intermediate the first  170  and second  172  ends. First and second through holes  176 ,  178  are provided at the first end  170  of the first lever  166 . The first through hole  176  mates with the through hole  28  of the first jaw  12 . The first lever  166  and the first jaw  12  are affixed together with attachment means, for example nut and bolt assembly  177 . Similarly, the second lever  168  includes a first end  180  and a second end  182 . A handle portion  184  is intermediate the first  180  and second  182  ends. First  186  and second  188  through holes are provided at the first end  180  of the second lever  168 . The first through hole  186  mates with the through hole  32  of the second jaw  14 . The second lever  168  and the second jaw  14  are affixed together with attachment means, for example nut and bolt assembly  187 . The levers  166 ,  168  are also pivotally attached directly together at through holes  178 ,  188  by attachment means, for example nut and bolt assembly  189 . The portion of the first lever between the first through hole  176  and the second through hole  178  thus forms a first linkage  190 . Similarly, a second linkage  192  is formed by the portion of the second lever between the first through hole  186  and the second through hole  188 . The jaws  12  and  14  may thus be viewed as being alternatively opened and closed by the oscillating pivoting motion of the linkages  190  and  192 . The jaws  12  and  14  are put in an open position when the linkages  190  and  192  are pivoted away from the pivot points  24  and  38  (as illustrated in  FIG. 10 ), and put in a closed position when the linkages  190  and  192  are moved in line with one another (as illustrated in  FIG. 11 ). The levers  166  and  168  are biased into an open position by spring element  194 . 
   The preferred material of construction for the levers  166  and  168  and the attachment means is hardened tool steel. Other materials, for example, stainless steel or other combinations of materials, for example hardened tool steel encased in a plastic coating, could be substituted. The preferred material of construction for the spring element  194  is spring steel. 
   From this disclosure, it would be obvious to one skilled in the art to modify the arrangement of the levers as shown. The length and thickness proportions of the levers with respect to the jaws  12  and  14  could be increased or decreased. The surface of the levers  166  and  168  could be modified to provide a non-slip grip. Cushioning materials (e.g. polypropylene foam) could be used to cover the levers  166  and  168 . 
     FIGS. 12 and 13  illustrate a fifth embodiment of the present invention. A motorized hand tool  210  is comprised of the first embodiment  10  of the cutting tool combined with a motorized drive for applying actuating forces to jaws  12  and  14 . The motorized drive includes a drive mechanism  212 , a hand-held motorized device  214 , capable of rotating an output shaft at a suitable rotational velocity and of providing satisfactory torque to the output shaft and a housing  216  (note that a mating housing is omitted from the FIGS. to allow the internal mechanism to be seen). The hand-held motorized device  214  is a commercially available item, and may be purchased from Makita Power Tools, Model Number 6333D. The housing  216  attaches to the hand-held motorized device  214 , and surrounds the drive mechanism  212  and a portion of the cutting tool  10  proximate ends  18  and  32 . The housing  216  is attached to the jaws  12  and  14  in the same manner and functions in the same way as link  44 . The drive mechanism  212  includes first  218  and second  220  linkages. The first linkage  218  has first  222  and second  224  ends. A first through hole  226  is provided at the first end  222  and a second through hole  228  is provided at the second end  224 . The first linkage  218  is connected to the first jaw  12  by a fastener (e.g. a rivet, not shown) inserted in mating through holes  226  and  28 . Similarly, the second linkage  220  has first  230  and second  232  ends. A first through hole  234  is provided at the first end  230  and a second through hole  235  is provided at the second end  232 . The second linkage  220  is connected to the second jaw  14  by a fastener (e.g. a rivet, not shown) inserted in mating through holes  234  and  42 . 
   The drive mechanism  212  further includes a bevel gear  236  mounted to an output shaft  238  of the hand-held motorized device  214 . The bevel gear  236  drives another, larger bevel gear  240 . A cam link  242  is connected at one end to the bevel gear  240 . The cam link  242  is connected at its opposite end to the two links  218  and  220 , at mating through holes  228 ,  235 . As the output shaft  238  of the hand-held motorized device  214  rotates, the bevel gear  236  turns the larger bevel gear  240 . As the bevel gear  240  rotates, the cam link  242  pushes the links  218  and  220  in an oscillatory pivoting motion. As illustrated in  FIG. 12 , when the cam link  242  is in a “three o&#39;clock” position relative to the bevel gear  240 , the links  218  and  220  are parallel to one another, and the jaws  12  and  14  of the cutting tool  10  are closed. As illustrated in  FIG. 13 , when the cam link  242  is in its “nine o&#39;clock” position relative to the bevel gear  240 , the links  218  and  220  are in their most forward pivoted configuration, and the jaws  12  and  14  are fully open. 
   The preferred material of construction for the linkages  218  and  220  and cam linkage  242  is hardened tool steel. Other materials, for example, stainless steel, could be substituted. The preferred material of construction for the pinion gear  236  and the bevel gear  242  is tool steel, but other materials (e.g. bronze) could be substituted. The preferred material of construction for the housing  216  is carbon steel, but other materials (for example, polypropylene, ABS or PVC) could be substituted. 
   From this disclosure, it would be obvious to one skilled in the art to modify the arrangement of the drive mechanism  212  as shown. For example, the sizes of the pinion gear  236  and the bevel gear  240  could be modified to change the performance characteristics of the drive mechanism  212 . 
   A sixth embodiment of the present invention is illustrated in  FIGS. 14–16 . A motorized hand tool  310  is comprised of the first embodiment  10  of the cutting tool of the present invention and the hand-held motorized device  214  of the fifth embodiment of the present invention. The cam link  242  of the fifth embodiment of the present invention is modified in the sixth embodiment, resulting in cam link  342 . Cam link  342  is larger at its base portion  342   a , allowing the cam link  342  to be mounted to the bevel gear  240  farther from the center of rotation of the bevel gear  240 , thus resulting in more highly eccentric motion than occurs in the fifth embodiment. This allows the cam link  342  to move through a longer stroke at its opposite end as the base portion  342   a  moves eccentrically about bevel gear  240 . Additionally, the housing  316  of the sixth embodiment is lengthened relative to the housing  216  of the third embodiment to accommodate both the longer stroke and the increased length of the cam link  342 . The motivation for increasing the stroke of the cam link  342  is to allow the jaws  12  and  14  to move through two full cutting cycles per full revolution of the bevel gear. As illustrated in  FIG. 14 , the cutting tool  10  is fully closed when the cam link  342  is at its “6 o&#39;clock” position, as well as when it is at its “12 o&#39;clock” position.  FIGS. 15 and 16  illustrate that the jaws  12  and  14  are fully opened when the cam link is at its “3 o&#39;clock” and “9 o&#39;clock” positions. 
   A seventh embodiment of the present invention is shown in  FIGS. 17 and 18 . This embodiment incorporates a fourth embodiment of the cutting tool,  10 ′″. In the fourth embodiment of the cutting tool  10 ′″, the first jaw  12 ′″ is provided with a cutting edge  26 ′″, while the opposing edge  40 ′″ of the second jaw  14 ′″ forms a cutting anvil  196 ′″. The cutting anvil  196 ′″ is formed by a metallic insert, preferably brass. The cutting anvil  196 ′″ is secured into the second jaw  14 ′″ by fasteners  197 ′″, preferably rivets. The second jaw  14 ′″ is integrally formed with a first actuating lever  166 ′″, preferably formed from a rigid plastic material, such as ABS plastic. The first jaw  12 ′″ is fixedly attached to a second actuating lever  184 ′″ by fastening means  198 ′″, preferably rivets. First jaw  12 ′″ is preferably fabricated from hardened tool steel, while second actuating lever  184 ′″ is preferably formed from a rigid plastic, such as ABS plastic. The first jaw  12 ′″ is preferably provided with a coating, for example Teflon® or chrome to facilitate release of the workpiece  64  from the cutting edge  26 ′″. The first and second jaws  12 ′″,  14 ′″ are pivotally connected by fastening means  63 ′″, preferably a rivet. A flat spring  194 ′″ biases the first and second jaws  12 ′″,  14 ′″ in an open position. 
   From this disclosure, it would be obvious to one skilled in the art to modify the seventh embodiment  110 ′″ of the present invention as shown. The cutting tool  10 ′″, with its combination of a cutting edge  26 ′″ with a cutting anvil  196 ′″ could be incorporated into any of the foregoing embodiments. 
   A cutting tool  10 ,  10 ′,  10 ″ and  10 ′″ is thus disclosed, suitable for cutting thin or thick and hard (metal) or soft (wood) materials with reduced blade movement. 
   It will be appreciated by those skilled in the art that changes could be made to the embodiments described above without departing from the broad inventive concept thereof. It is understood, therefore, that this invention is not limited to the particular embodiments disclosed, but it is intended to cover modifications within the spirit and scope of the present invention as defined by the appended claims.