<div class="application article clearfix" id="description">
<p class="printTableText" lang="en">zutitf 8 1 <br><br>
Priority Date(s): <br><br>
Complete Specification Filed: <br><br>
Class: RAl M[42 <br><br>
Publication Date: 5. J. !WJ??7. <br><br>
P.O. Journal, No: • • • • /• • • • • <br><br>
NEW ZEALAND <br><br>
PATENTS ACT, 1953 <br><br>
No.: Date: <br><br>
COMPLETE SPECIFICATION <br><br>
JHJ*mrroFRcE 12 JUL 1984 ;jQ£££l\f£D ;ALL-WAY OFFSET SNIPS CUTTING TOOL WITH FULL WIDTH WIRE CUTTER ;X/We, PROSNIP CORPORATION, a corporation of the State of Nebraska, United States of America, of Dewitt, Nebraska, 68341, ;United States of America hereby declare the invention for which jj / we pray that a patent may be granted to 3ficfe/us, and the method by which it is to be performed, to be particularly described in and by the following statement:- ;2088.11 ;ALL-HAY OFFSET SNIPS CUTTING TOOL WITH FULL WIDTH WIRE CUTTER ;This application is related to applicant's United States Patent No. 4,463,497 filed on June 7, 1982 by James R. O'Keefe as inventor and entitled "Improved Offset Snips". ;BACKGROUND OF THE INVENTION ;The present invention relates to an improved hand operated offset shears or snips which can be used for cutting sheet metal or similar material in either a straight line or In a right or left hand direction, including circle cuts down to an opposing circle of about 2.0" to 2.5" in diameter. ;When sheet metal or similar material is cut with conventional snips, one or both edges of the cut sheet material may interfere with the body of the snips, making It difficult to advance the snips into the sheet material and distorting the cut edges. This interference is greatest when cutting irregular shapes, particularly sharp curves and especially small circles. Accordingly, conventional snips are often supplied in mirror image configurations particularly adapted for either .left-hand or right-hand turning cuts. Also, when conventional snips are used to cut thick, tough or stiff material, the sheet material may tend to slide away from the blades as they are closed, decreasing the efficiency of the cutting. Further, conventional snips may require long handles and sub-stantial force to be exerted by the operator in order to cut many sheet materials. ;As illustrated by U.S. Patent No. 2,264,840, one approach to decreasing the interference of the cut sheet material with the body of the snips is to offest the cutting surfaces with respect to the shank portions of the snips such ;that the cut sheet material passes to one side of the shank portions. Also illustrated therein is the practice of extending the cutting blades laterally approximately at right angles to the place of operation of the shanks. This configuration facilitates the advancement of the snips into the sheet material by reducing the extent to which the cut sheet material must be spread vertically to pass above and below the lower blade, thereby decreasing the tendency of the sheet material to slide away from the cutting surfaces. More recently, a link arrangement, as shown in U.S. Patent No. 3,587,173, has been proposed to reduce the force required by the operator to cut heavy sheet materials. ;As with conventional snips, most available offset snips generally can be used only in cutting curves either In the left-hand or right-hand direction, thus requiring other offset snips having a mirror image configuration when curves must be made in the other direction. Also, the laterally extending blades of available offset snips must be carefully ground and aligned during manufacture and, generally, cannot be conveniently reground if they become dull or damaged. Abuse of the blades by cutting wire or similar materials may render the snips useless for cutting sheet material. Accordingly, a need exists for improved offset snips which can be easily resharpened if the blades become dull or damaged, and which embodies a pinch or shear type wire cutter. Further, there is a need for an improved handle and toggle arrangement or configuration making the offset snips more powerful and convenient to use when cutting heaving sheet material. ;In applicant's related U.S. patent application, a pinch type cutter is employed where part of the upper blade ;2 ;— W ■ ;member serves as the anvil and a portion of the lower blade member serves as the chisel for the wire cutter. With such an arrangement, a "relief" formed at the base of the cutter elements, due to the manufacturing processes involved, requires wire that is to be cut to be specifically positioned substantially centrally in the cutter. Should, for example, a small diameter wire be positioned at the base of the cutter, the "relief" in effect precludes the wire from being cut by the chisel and anvil. This "relief" is created as a result of the various grinding operations or passes required in order to grind the opposite faces of the chisel. Also, In the formation of the chisel of such related patent application, the grinding passses generally create a broad V-shaped chisel having an angle between the sides thereof of about 70 degrees. Such an angular chisel configuration, although adequate for most applications, requires more difficult manufacturing processes to fabricate resulting In considerably higher product cost. It also requires higher pressures and forces to cut wire as the chisel has a broader cutting angle and wire of smaller and even larger gauges can easily become snagged or trapped at the base of the cutter in the "relief" area. Such an occurrence then makes it difficult to cut the wire and one must manually reposition the wire centrally so that the chisel cuts or pinches across the full width of the wire with the wire trapped squarely between the anvil and full face width of the chisel. ;Another disadvantage of applicant's related patent application is the fact that the lower blade member, although offset, does not provide adequate clearance so that very small opposing diameter circle cuts cannot be made. This deficiency makes it necessary to fabricate and stock both ;808381 ;left and right hand cutters as neither offset snips is truly considered an all-way or universal type of snips capable of cutting in any direction, that is, straight, right-hand and left-hand. It should he recognized that for most applications, cutting arcs, curves, or circles down to at least about 2.0" to 2.5" in diameter would satisfy most field requirements of the tool. ;It is therefore an object of the present invention to provide universal offset snips for cutting wire and for cutting sheet metal or the like in substantially any direction which overcomes at least some of the above mentioned disadvantages. ;It is a preferred feature of the present invention to provide improved all-way offset snips which can cut sheet material in both left-hand and right-hand curves, as well as in very small diameter circles, without being impeded by interference of the cut material with the body of the snips. ;It is a further preferred feature of the present invention to provide improved all-way offset snips of increased power and in which the cutting surfaces may be conveniently and economically resharpened if the cutting surfaces become dull or damaged, and resharpening of the chisel of the wire cutter can be done by a single grinding pass with the boss of its blade member. ;It is a further preferred feature of the present invention to provide improved all-way offset snips having either pinch or shearing means for cutting wire and the like, thereby eliminating the need for a second tool and reducing the abuse of the sheet material cutting surfaces of the offset blade members. ;It is a further preferred feature of the present invention to provide improved all-way offset snips having substantially increased power due to a toggle arrangement which provides greater force action to the central toggle pivot of a dual link/three pivot point toggle linkage because of the general ;4 ;208381 ;linearity of the toggle pivot points when the offset snips is in closed position. ;It is still a further preferred feature of the present invention to provide an "all-way" offset snips having handles with a toggle linking arrangement of considerably greater power which can more easily be grapsed when the snips are in the open position and more easily forced to the closed position. ;It is yet another preferred feature of the present invention to provide an all-way offset snips having either a pinch or shear type cutter, with the anvil portion of the pinch cutter on the upper blade member and the chisel on the lower blade member regardless of the type of cutter which is employed. ;It is still yet another preferred feature of the present invention to provide an all-way offset snips having a chisel which can be sharpened in a single grinding pass with the boss of its blade member and which cuts across the full width of the a nvi1. ;SUMMAKY OF INVENTION ;The present invention is directed to improvements in hand operated all-way shears or snips with full width wire cutting means for cutting sheet material and wire or other rod-like materials. ;Accordingly the invention consists in universal offset snips for cutting wire and for cutting sheet metal or the like in substantially.any direction, having upper and lower blade members having, respectively, flat first and second pivot bosses and first and second cutting surfaces offset with respect to the plane of said first and second pivot bosses; and pivot means pivotably connecting the upper and lower blade members for rotation about an axis perpendicular to the first and second pivot bosses by opposite handle means pivoting the upper and lower blade members about said pivot means such that the first and second cutting surfaces are movable between an open position and a closed position for cutting sheet metal ;5 ;therebetween; comprising; ;an upwardly extending portion of said first pivot boss forming a beveled chisel 6dge of a wire cutter, said upwardly extending portion being formed such that removal of material from theJsaid pivot boss including said upwardly extending portion serves to sharpen : ;said chisel edge; an upwardly extending portion on said lower blade member serving as ao opposing wire cutter surface to said chisel edge; ;both said pivot bosses and the cutting surfaces being adapted for removal of materials therefrom for resharpening the cutting surfaces while maintaining the offsets therebetween with the first and second pivot bosses serving as reference surfaces to facilitate resharpening of the offset snips; and the opposing surface of said wire cutter incorporating the full face width of said chisel edge, whereby pinching and snagging of said wire during cutting is precluded, and said offset snips are capable of small opposing circle cuts down to at least substantially 2.0" to 2.5" in diameter. ;i''V ;12FEBI98Zj ;BRIEF DESCRIPTION OF THE DRAWINGS ;FIGURE 1 is a side elevaclonal view of an embodiment of Che offset snips of the present invention shown in the open position and with portions broken away; ;FIGURE 2 is a side elevational view of the offset snips of FIGURE 1 shown in the closed or cutting position and with portions broken away; ;FIGURE 3 is a sectional view.of the offset snips of FIGURES 1 and 2 taken along the line of 3-3 of FIGURE 2; ;FIGURE 4 is a side elevational view of the upper cutting blade of the offset snips of FIGURES 1 to 3; ;FIGURE 5 is a sectional view of the upper cutting blade of the offset snips of FIGURES 1 to 3 taken along the line 5-5 of FIGURE 4; ;FIGURE 6 is a sectional view of the upper cutting blade of the offset snips of FIGURES 1 to 3 taken along the line 6^6 of FIGURE 4; ;FIGURE 7 is a side elevational view of the lower ;'.^cutting blade of the offset snips of FIGURES 1 to 3; ;• 7 ;w <>#■ vv# u | ;FIGURE 8 is a sectional view of the lower cutting blade of the offset snips of FIGURES I to 3 taken along the line ;8-8 of FIGURE 7; ;FIGURE 9 Is a sectional view of the lower cutting blade of che offset snips of FIGURES 1 to 3 taken along the line ;9-9 of FIGURE 7; ;FIGURE 10 i 8 a side elevational view of a more preferred embodiment of the offset snips of the present invention shown in the open position and with portions broken away; ;FIGURE 11 is a side elevational view of the offset snips of FIGURE 10 shown locked in the closed or cutting position and with portions broken away; ;FIGURE 12 is a sectional view of the offset snips of FIGURES 10 and 11 taken along the line 12-12 of FIGURE 11; ;FIGURE 13 is a side elevational view of the upper cutting blade of the offset snips of FIGURES 10 to 12; ;FIGURE 14 is a sectional view of the upper cutting blade of the offset snips of FIGURES 10 to 12 taken along the line 14-14 of FIGURE 13; ;FIGURE 15 is a sectional view of the upper cutting blade of the offset snips of FIGURES 10 to 12 taken along the ;\ ;line 15-15 of FIGURE 13; ;FIGURE 16 is a side elevational view of the lower cutting blade of the offset snips of FIGURES 10 to 12; ;FIGURE 17 is a sectional view of the lower cutting blade of the offset snips of FIGURES 10 to 12 taken along the line 17-17 of FIGURE 16; ;FIGURE 18 is a sectional view of the lower cutting blade of the offset snips of FIGURES 10 to 12 taken along the ;8 ;2088 8 T ;line 18-18 of FIGURE 16; and ;FIGURES 19a and 19b are fragmentary top views of opposing shearing blades of typical shear type cutters which may, if desired, be employed in lieu of the pinch cutter. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS ;With reference to the drawings, one embodiment of offset snips made in accordance with the present Invention is indicated generally by the numeral 10 in FIGURES 1 to 3. The cutting snips 10 Include upper and lower blade members, indicated generally by the numerals 12 and 14, respectively, which are pivotably moveable about a main pivot bolt 16 by upper and lower handles, indicated generally by the numerals 18 and 20, respectively. Movement of the blade members 12 and 14 between the open position shown in FIGURE 1 and the closed position shown in FIGURE 2 effects cutting of a sheet material workpiece 22 or a wire workpiece 24 positioned between the blade members 12 and 14, as shown in FIGURE 1. ;The handles 18 and 20 are pivotably moveable about a handle pivot bolt 26 located lntermediatley of the ends of the handles 18 and 20. The rearward portions 28 and 30 of the respective handles 18 and 20 are covered with upper and lower hand grips 32 and 34, respectively. Preferably, the hand grips 32 and 34 are formed by dipping or molding so as to include outwardly projecting ear portions 36 and 38, respectively, to prevent the hand of the operator from sliding forward during use of the cutting snips 10. The preferred material for the hand grips 32 and 34 is a hot-dip plastisol such as that commercially available from Sinclair Rush of St. Louis, Missouri. ;The handles 18 and 20 extend forward from the handle pivot bolt 26 and away from each other for pivotable mounting ;20888 1 ;Co Che blade members 12 and 14 at pivot bolts 40 and 42, respectively. In the open position shown in FIGURE 1, an acute angle is, preferably, formed between an imaginary line joining Che plvoc bolts 26 and 40 and an imaginary line joining pivot bolts 26 and 42. Preferably, the handles 18 and 20 have a U-shaped cross-section, as shown in FIGURE 3, formed by laterally spaced side portions 44 and 46 joined by a web portion 48. An omega spring SO, held in place by the handle pivot bolt 26, engages the web portion 48 of the handles 18 and 20 to bias the cutting snips 10 into the open position. Other biasing means could be employed with similar effect. A sleeve 51 is positioned between the handle pivot screw 26 and the omega spring 50 to center and space the omega sping 50 with respect to the handle pivot .screw 26. Although the sleeve 51 is not essential to the operation of the cutting snips 10, Applicant has found that the sleeve 51 subsCanCially extends the cycle life of Che omega spring 50. ;In Che open posiclon, Che upper blade member 12 exCends upward and rearward from the main pivot bolt 16 to a pivotable mounting upon the pivot bolt 40, as shown in FIGURE 1 . The lower blade member 14 extends rearward from the main pivot bolt 16 to a pivotable mounting upon the pivot bolt 42. In response to the closing of the handles 18 and 20, the pivot bolts 40 and 42 are rotated about the handle pivot bolt 26, thereby spreading the rearward portions 54 and 56 of the blade members 12 and 14. As illustrated in FIGURE 3, the rearward portions 54 and 56 have sufficient thickness to be closely received by the side portions 44 and 46 of the handles 18 and 20 so as to maintain alignment of the upper and lower cutting blades 12 and 14. Adustment of the play ;10 ;between the side portions 44 and 46 and the rearward portions 54 and 56 is provided by adjustment nuts 58 upon the pivot bolts 40 and 42. ;The main pivot bolt 16 is threaded into a hole 60 in the shank portion 62 of the upper blade member 12 and forms a sliding fit with a hole 64 within the shank portion 66 of the lower blade member 14. A lock nut 68 is locked against the shank portion 62 to maintain the adjusted length of the main pivot bolt 16. Cutting surfaces 70 and 72 of the cutting blades 12 and 14, respectivley, are within a plane substantially parallel to but offset laterally from the adjoining shank portions 62 and 66 of the respective blade members, as shown in FIGURE 3. It will be noted that the offset is sufficient to permit a cut portion of the sheet material workpiece 22 to pass to the side of the shank portion 66. ;Applicant has found that the cutting of the sheet material workpiece 22 Is enhanced if the cutting surfaces 70 and 72 are curved In side elevation, as shown in FIGURES 4 and 7, so as to present convex cutting surfaces to the work-piece. In the preferred embodiment shown, the upper cutting surface 70 is defined by an 8 inch radius, and the lower cutting surface 72 is also defined by an 8 inch radius. However, the configuration illustrated is merely illustrative as various other curved configurations could be utilized with similar effect. As is evident from FIGURES 4 to 8, forward portions 84 and 86 of the respective blade members. 12 and 14 extend laterally nearly perpendicular to the shank portions 62 and 66. This configuration facilitates the cutting of a sheet material workpiece 22 which is placed upon a flat surface such as a table and, further, minimizes the amount ;1 1 ;that the cut surfaces of the workpiece must be spread apart as they pass above and below the lower blade member 14. ;Preferably, the blade members 12 and 14 are hollow ground along the surfaces 78 and 80, respectively, to ensure that the upper and lower cutting surfaces 70 and 72 have a uniform width in side elevation while providing for resharpening of the blade members, as described below. The rearward portion of the lower cutting surface 72 is provided with a relief 82 to facilitate grinding of the cutting surface 72 and to ensure smooth sliding engagement of the cutting surfaces 70 and 72 during cutting. The forward portions 84 and 86 of the blade members 12 and 14 are curved inward as shown in FIGURES 6 and 9 to form convex surfaces. This configuration of the forward portions 84 and 86 provides sufficient strength for the cutting surfaces 70 and 72 while permitting the cutting snips 10 to be maneuvered for cutting when space is limited. ;Cutting of the wire workpiece 24 is provided by engagement of an anvil portion 88 formed upon the upper blade member 12 by a chisel or wedge portion 90 formed upon the lower blade member 14. The placement of the anvil portion 88 and the wedge portion 90 is such that their engagement provides a stop to limit rotation of the blade members when the cutting snips 10 are in the closed position shown in FIGURE 2. The wedge portion 90 serves as a chisel to sever a wire, rod, small bar or the like placed upon the anvil portion 88 when the cutting snips 10 are moved from the open position shown in FIGURE 1 to the closed position of FIGURE 2. It will be appreciated that other opposed cutting surfaces such as, for example, those of "diagonal" cutters ;12 ;V UU o I ;nay be used in place of the anvil portion 88 and the wedge portion 90 with similar effect. ;It is an Important feature of the present invention that ttie cutting surfaces 70 and 72 may be reground to renew worn or damaged cutting surfaces. Referring to FIGURE 3, it will be apparent that grinding back either the upper cutting surface 70 or the lower cutting surface 72 would normally be expected to result in a lateral space between the cutting surfaces 70 and 72, thereby precluding shearing of the sheet material workpiece 22. The offset of the cutting surface 70 ;with respect to the shank portion 62 is decreased by such ;\ ;grinding, and the offset of the cutting surface 72 with respect to the shank portion 66 is Increased by such grinding. For this reason, the commercially available offset snips cannot be conveniently resharpened once they become dull or damaged. ;Resharpening of the cutting snips 10 of the present invention is facilitated by pivot bosses, indicated generally by the numerals 92 and 94, upon the adjacent surfaces of the shank portions 62 and 66, respectively. The pivot bosses 92 and 94 axe flat projections above the surface of the shank portions 62 and 66 perpendicular to the main pivot bolt 16. The pivot boss 92 need not be of any particular configuration but, by way of example, may Include a semi-circular forward portion 96 concentric with the main pivot bolt 16 and a rectangular rearward portion 98, as shown in FIGURE 4. Similarly, by way of example, the pivot boss 94 may Include a s emi-ci r ciila r forward portion 100 concentric with the main pivot boLt 16 and a triangular rearward portion 102 as indicated in FIGURE 7. The pivot bosses 92 and 94 provide improved bearing surfaces between the blade members 12 and 14 ;13 ;Abb ^ar while maintaining alignment of the cutting surfaces 70 and 72. The rearward portions 98 and 102 cooperate to prevent the cutting surfaces 70 and 72 from spreading apart during the cutting stroke. ;In the cutting snips 10, the offset of the cutting surfaces 70 and 72 ia determined by the location of the pivot bosses 92 and 94. As a result, resharpening of the cutting snips 10 can be provided by grinding both the cutting surfaces 70 and 72 and the respective pivot bosses 92 and 94. It will be appreciated that no change in the offset of the upper cutting surface 70 will occur if equal thicknesses of material are ground from the upper cutting surface 70 and the pivot boss 92. Similarly, no change in the offset of the lower cutting surface 72 will ocur if equal thicknesses of material are ground from the lower cutting surface 72 and the pivot boss 94. Thus, either or both of the blade members 12 and 14 may be sharpened as required without producing a lateral space between the cutting surfaces 70 and 72. ;Resharpening of the respective blade members is further simplified because no curved surfaces require regrinding. The upper and lower cutting surfaces 70 and 72 are ground in a plane which is substantially parallel to the respective pivot bosses 92 and 94. The pivot bosses 92 and 94 may be machined first to provide reference surfaces for the grinding of the cutting surfaces 70 and 72. The hollow ground portions 78 and 80 of the respective blade members 12 and 14 eliminate the need to grind any other surfaces during resharpening. Applicant has found that sufficient regrinding capability is provided if the height of the pivot bosses 92 and 94 above the adjacent shank portions 62 and 66 is 1/32 of ;14 ;an inch. The articulation of the blade members 12 and 14 with respect to the handles 18 and 20 permits the cutting surfaces 70 and 72 to be positioned in a grinding fixture with the pivot bolts 26, 40 and 42 in place, only the main pivot bolt 16 having been removed. ;Applicant has found that the cutting of the sheet material workpiece 22 Is enhanced if the upper and lower cutting surfaces 70 and 72 are not exactly parallel with respect to the pivot bosses 92 and 94 but, instead, are angled slightly so as to establish progressive interference as the blade members are closed. Although various amounts of interference may be used with similar effect, Applicant prefers an angle of approximately 15 minutes on each of the cutting surfaces 70 and 72 so as to establish a total interference of approximately one-half a degree. This interference forces the blades tightly together during the latter part of the cutting stroke to ensure a shearing action. The desired angle and offset can be conveniently and economically formed when the blade members 12 and 14 are initially ground or subsequently reground to effect resharpening. ;It will be appreciated that grinding of the pivot bosses 92 and 94 is merely illustrative of the inventive concept of removing material from the adjacent shank portions 62 and 66 of the upper and lower blade members 12 and 14 to permit resharpening of the cutting surfaces 70 and 72. Milling or other cutting means could also be employed in place of grinding provided that such cutting means is not precluded by the hardness of the blade members 12 and 14. ;Another feature is the locking means which can be engaged manually to prevent the cutting snips 10 from opening from the closed position shown in FIGURE 2. The pivot bolt ;15 ;i. VUU U I ;40 is formed with a shoulder portion between the shank portion and the head portion. A lock strap 104 is pivotably mounted upon the pivot bolt 42 outside the laterally spaced side portions 44 and 46 of the upper and lower handles 18 and 20. The free end of the lock strap 104 is notched in a side portion thereof so as to form a hook surface 106. The lock strap 104 is moveable manually between the pivot bolt 40 and the handle pivot 26 from a first position shown in FIGURE 1 which permits operation of the cutting snips 10 to a second position shown in FIGURE 2 which locks the cutting snips 10 in the closed position. In the second position, the hook surface 106 of the free end of the lock strap 104 is rotated into engagement with the shoulder portion of the pivot bolt 40 such that the lock strap 104 is held in compression by the omega spring 50. The lock strap 104 may conveniently be released or engaged by the operator's thumb to permit one-hand operation. ;It is another important feature of the cutting snips 10 that a triangular notch or recess 110 is provided in the shank portion 66 of the lower blade member 14 in line with the path of the cut sheet material workpiece 22 passing above the forward portion 86 of the lower blade member 14. The recess 110 permits the cutting snips 10 to cut right-hand as well as left-hand turning cuts. It will be appreciated that the configuration of the cutting snips 10 shown in the preferred embodiment is particularly suited for straight and left-hand turning cuts. However, applicant has found that the recess 110 permits right-hand turning cuts having a 4 inch or larger diameter, thereby eliminating the need for separate cutting snips particularly adapted for right-hand ;16 ;turning cuts. Similar cutting snips could be provided having a mirror image configuration which would be particularly suited for straight and right-hand turning cuts yet capable of 4 inch diameter left-hand turning cuts. ;It is still another Important feature of Che cutting snips 10 that the handles 18 and 20 are particularly convenient and adapted for applying force throughout the range of motion of the cutting blades 12 and 14. Unlike more conventional offset snips, the handle pivot bolt 26 is relatively close to the hand grips 32 and 34. As a result, the angle formed between the hand grips 32 and 34 when the cutting snips 10 are in the open position shown In FIGURE 1 can be greater than that of conventional snips. In the open position, the forward portions of the hand grips 32 and 34 are spaced apart to permit the handles 18 and 20 to be spanned by the operator's hand adjacent the ear portions 36 and 38 for maximum leverage. The lower handle 20 is configured such that the open position of the lower hand grip 34 does not interfere with a work-bench 'upon which the sheet material workpiece 22 is placed for cutting. As the upper and lower blade members 12 and 14 are moved toward the closed position shown in FIGURE 2, the more rearward portions of the upper and lower hand grips 32 and 34 are, progressively, Ideally spaced apart for maximum leverage. In addition, the blade members 12 and 14 and the handles 18 and 20 comprise a four bar linkage which provides amplification in transmitting the manually applied force to the cutting surfaces 70 and 72 to reduce operator exertion and fatique. ;A variety of materials may be used to form the blade members and the handles, depending upon the sheet material to be cut. In the preferred embodiments shown, the cutting ;17 ;blades are forged Co alloy tool steels and are ground to the configurations shown. Such construction provides sufficient strength to permit steel sheet to be cut by the cutting snips. However, other materials and less expensive forming methods may be used, particularly when less substantial sheet material is to be cut. The handles 18 and 20 may be conveniently and economically formed of mild steel by various stamping operations. The lock strap 104 may also be conveniently and economically formed of sheet steel. ;Referring now to FIGURES 10 to 19, an improved all-way offset snips cutting tool with an improved wire cutter is indicated generally by the reference numeral 10'. The snips 10' include upper and lower blade members 12'' and 14', respectively, which are pivotably moveable about a main pivot bolt 16' by upper and lower handles, indicated generally by the numerals 18' and 20', respectively. Movement of the blade members 12' and 14' between the open position shown in FIGURE 10 and the closed position shown in FIGURE 11 effects cutting of a sheet material workpiece 22' or a wire workpiece 24' positioned between the blade members 12' and 14', as shown in FIGURE 10. ;The handles 18' and 20' are pivotably moveable about a handle pivot bolt 26' locaCed intermediately of the ends of the handles 18' and 20'. The rearward portions 28' and 30' of the respective handles 18' and 20' are covered with upper and lower hand grips 32' and 34', respectively. Preferably, the hand grips 32' and 34' are formed by dipping or molding so as to include outwardly projecting ear portions 36' and 38', respectively, to prevent the hand of the operator from sliding forward during use of the cutting snips 10'. ;18 ;The handles 18' and 20' extend forward from the handle pivot bolt 26' and away from each other for pivotable mounting to the blade members 12' and 14' at pivot bolts 40' and 42', respectively. In the open position shown in FIGURE 10, an acute angle is, preferably, formed between an imaginary line joining the pivot bolts 26' and 40' and an imaginary line joining pivot bolts 26' and 42'. Such an acute angle is in the order of about 70 degrees in both embodiments of the invention. However, in the closed position, said angle between the two equally long imaginery lines is preferably increased by about 10 degrees to about 15 degrees (114 degrees to 119 degrees) resulting in a substantially more powerful grip due to the shallower toggle "linkage" and the general linearality of the toggle pivot points when the offset snips are in a closed position. With the pivot bolts 40' and 42' closer to the handle pivot bolt 26', the latter i8 much more closer to dead center where power is maximum for the toggle mechanism. Thus, in this embodiment of the invention, the distance between the handle pivot bolt 26' and the pivot bolts 40' and 42' is about 1/4 inch less which results in an improved offset snips of considerably greater power than that of the embodiment shown in FIGURES 1 to 8. Here in the closed position, the two opposite equal angles of the triangular "over-center" type toggle mechanism form angles with the further imaginary line joining pivot bolts 40' and 42' in the order of about 30 degrees to about 33 degrees. Preferably, the handles 18' and 20' have a U-shaped cross-sect1on, as shown in FIGURE 12, formed by laterally spaced side portions 44' and 46' joined by a web portion 48'. An omega spring 50', held in place by the handle pivot bolt 26', engages the web portion 48' of the handles 18' and 20' ;19 ;Co bias Che cutting snips 10' Into the open position. Other biasing means could also be employed with this embodiment of Che invention, and, although the "centering" sleeve 51' is not essential to the operation of the cutting snips 10', the sleeve 51' substantially extends the cycle life of the omega spring 50'. ;In the open position, the upper blade member 12' extends upward and rearward from the main pivot bolt 16' to a pivotable mounting upon the pivot bolt AO' as shown In FIGURE 10. The lower blade member 14' extends rearward from the main pivot bolt 16' to a pivotable mounting upon the pivot bolt 42'. In response to the closing of the handles 18' and 20', the pivot bolts 40' and 42' are rotated about'the handle pivot bolt 26', thereby spreading the rearward portions 54' and 56' of the blade members 12' and 14'. As illustrated in FIGURE 12, the rearward portions 54' and 56' have sufficient thiCKness to be closely received by the side portions 44' and 46' of the handles 18' and 20' so as to maintain alignment of the upper and lower cutting blades 12' and 14'. Adjustment of the play between the side portions 44' and 46' and the rearward portions 54' and 56' is provided by adjustment nuts 58,' upon the pivot bolts 40' and 42'. ;The main pivot bolt 16' is threaded into a hole 60' in the shank portion 62' of the upper blade member 12' and forms a sliding fit with a hole 64' within the shank portion 66' of the lower blade member 14'. A lock nut 68 is locked against the shank portion 62' to maintain the adjusted length of the main pivot bolt 16. Cutting surfaces 70' and 72' of the cutting blades 12' and 14', respectively, are within a plane substantially parallel to but offset laterally from the ad- ;20 ;^ w "H0 %J, ;joining shank portions 62' and 66' of the respective blade members, as shown in FIGURE 13. It will be noted that the offset in this embodiment of the invention is extended sufficiently to easily permit a cut portion of the sheet material workpiece 22' to pass to the side of the shank portion 66', but more importantly, to enable the improved tool to cut down to an opposing circle of about 2.0" to 2.5" in diameter. This arrangement permits one to cut sheet metal for most jots with a single tool as the "super" extended offset blades enable not only straight line cuts, but also sharp curves in either left or right hand directions. ;In this preferred embodiment of the invention, the cutting surfaces 70' and 72' are.also similarly curved in side elevation with like radii, as shown in FIGURES 13 and 16, so as to present convex cutting surfaces to the workpiece. Also, the forward portions 84' and 86' of the respective blade members 12' and 14' extend laterally nearly perpendicular to the shank portions 62' and 66', as in the embodiments of FIGURES 1 to 9. ;Preferably, the blade members 12' and 14' are hollow ground along the surfaces 78' and 80', respectively, to ensure that the upper and lower cutting surfaces 70' and 72' have a uniform width in side elevation while providing for resharpening of the blade members, as described below. The rearward portion of the lower cutting surface 72' is provided with a relief 82' to facilitate grinding of the cutting surface 72' and to ensure smooth sliding engagement of the cutting surfaces 70' and 72' during cutting. The forward portions 84' and 86' are curved inward as shown in FIGURES 15 and 18 to form convex surfaces. This configuration of the forward portions 84' and 86' provides sufficient strength for ;8 i' ;the cutting surfaces 70' and 72' while permitting the cutting snips 10' to be "maneuvered for cutting when space is limited. ;Cutting of the wire workpiece 24' is provided by engagement of an anvil portion 88' formed upon the lower blade member 14' by a chisel or wedge portion 90' formed upon the upper blade member 12'. The placement of the anvil portion 88' and the wedge portion 90' is such that their engagement provides a stop to limit rotation of the blade members when the cutting snips 10' are in the closed position shown in FIGURE 11. The wedge portion 90' serves as a chisel to sever a wire, rod, small bar or the like placed upon the anvil portion 88' when the cutting snips 10' are moved from the open position shown in FIGURE 10 to the closed position in FIGURE 11. It will be appreciated that the opposed cutting surfaces cut vire by means of pinch cutting which is preferable to other cutting means, such as shear cutting, as a separate limit stop is not required. With shear cutting surfaces in the form of "scissor-like" cutting blades between portions of the opposite blade members, the snips would also require a pair of mating abutments 89 and 91 (limit stop) between the handle blades for limiting rotation of the blade members (as best shown In phantom in FIGS. 10 to 11). Such a limit stop is necessary in each of the embodiments of FIGURES 19a and 19b where shear type vire cutters are substituted for pinch type wire cutters. With a shear type cutter of FIGURE 19a employed, the anvil portion 88' is simply ground down to clear the cutting blade or chisel 90' and movement of the chisel 90' (shown in phantom) past the opposing shear edge 93' cuts the wire (also shown in phantom). In FIGURE 19b, the opposing shear edge 93' is outwardly offset as the ;22 ;20888 t sharp cutting edge of the shear blade or chisel 90' is disposed at an angle opposite to that of the chisel 90' shown In FIGURE 19a. ;With either a pinch cutter or the shears type cutter, no relief is required at the base of the cutter elements as the chisel or knife edges are all sharpened by grinding across the full face of the cutter elements. With the Improved snips of the invention, only a single grinding pass need be made to fopm either type of cutter as the cutters are formed by grinding an angled or beveled edge from a straight edge. Thus, such a knife edge or shear blade formed thereby can be substantially smaller In angle size and therefore considerably more sharper than a more conventional blunt V-shaped angled pinch cutter. For example, approximately a 70 degree angle is provided in the chisel of FIGURES 1 to 9, whereas in the preferred embodiment an angle of about 40 degrees to about 60 degrees is satisfactory. It Is believed that considerably less friction is'generated during cutting with the small angled cutter of the present Invention as compared to the earlier pinch cutter. In such cases, the blade members are inherently made of stronger steels in order to maintain a sharp cutting edge or edges. Preferably, an angle of about 50 degrees has been found to be suitable for the practice of the Invention. It should also be appreciated that with a blunt angle of 70 degrees for the V-shaped pinch cutter FIGURES 1 to 9, greater forces are required to pinch or cut wire as the wider wedge-shaped chisel is believed to generate considerably more frictional resistance to cutting. ;It . shall be recognized that with the full face width cutters of the present invention, very small wires can be easily cut as there is no "relief" at the base of any cutter. ;23 ;4.VOQ O 1 ;Thus, the small wire can be positioned anywhere along the cutting edge or anvil, be it the pinch or shears type, without any fear that the small wire will be hung-up in a "relief" at the base of the cutter or anvil and either not be cut or incompletely cut. With such situations, one must then accurately reposition the wire in the center of the cutter in order to recut the wire in another spot, or finish the incomplete cut at the same spot, or to recut as close to the first attempt as one could conceivably achieve without the aid of any special tools to acurately align the cutter up for a "second" bite at the wire. ;It 18 an important feature of the present invention that the cutting surfaces 70' and 72' may be reground to renew worn or damaged cutting surfaces. Referring to FIGURE 12, it will be apparent that grinding back either the upper cutting surface 70' or the lower cutting surface 72' would normally be expected to result in a lateral space between the cutting surfaces 70' and 72', thereby precluding shearing of the sheet material workpiece 22'. The offset of the cutting surface 70' with respect to the shank portion 62' Is decreased by such grinding, and the offset of the cutting surface 72' with respect to the shank portion 66' is increased by such grinding. For this reason as noted hereinbefore, commercially available offset snips cannot be conveniently resharpened once they become dull or damaged. ;Resharpening of the cutting snips '10 of the present invention is facil'itated by pivot bosses, indicated generally by the numerals 92' and 94', upon the adjacent surfaces of the shank portions 62' and 66', respectively. The pivot bosses 92' and 94' are flat projections above the surface of ;24 ;the shank portions 62' and 66' perpendicular to the nain pivot bolt 16', The pivot boss 92' in the preferred embodiment is of particular configuration in that it includes a portion 96' generally concentric with the main pivot bolt 16' and a generally slender rectangular upward portion 97, as shown in EIGURE 13. Pivot boss 94' includes a generally circular portion 100' concentric with the main pivot bolt 16' and a generally upwardly extending portion 101, as indicated in FIGURE 16. The pivot bosses 92' and 94' provide improved bearing surfaces between the blade members 12' and 14' while maintaining alignment of the cutting surfaces 70' and 72'. The upward portions 97 and 101 also respectively reinforce the strength of the anvil portion 88' as well as the chisel 90' itself. ;In the cutting snips 10', the offset of the cutting surfaces bosses 70' and 72' is determined by the location of the pivot bosses 92' and 94'. As a result, resharpening of the cutting snips 10' can be provided by grinding both the cutting surfaces 70' and 72' and the respective pivot bosses 92' and 94' (and their upward portions 97 and 101 as well). The grinding of the pivot boss 92' across the full face thereof including the upwardly extending portion 97 also serves to sharpen the. chisel 90' of the wire cutter. ;It will be appreciated that no change in the offset of the upper cutting surface 70' will occur if equal thicknesses of material are ground from the upper cutting surface 70' and the pivot boss 92'. Similarly, no change in the offset of the lower cutting surface 72' will occur if equal thicknesses of material are ground from the lower cutting surfaces 72' and the pivot boss 94'. Thus, either or both of the blade members 12' and 14' may be resharpened as is periodically required during normal use without producing a lateral space between the cutting surfaces 70' and 72'. ;v simplified because no curved surfaces require regrinding. The upper and lower cutting surfaces 70' and 72' are ground in a plane which is substantially parallel to the respective pivot bosses 92' and 94'. The pivot bosses 92' and 94' may be machined first to provide reference surfaces for the grinding of the surfaces 70' and 72'. The hollow ground portions 78' and 80' of the respective blade members 12' and 14' eliminate the need to grind any other surfaces during resharpening. Applicant has found that, sufficient regrinding capability is provided if the height of the pivot bosses 92' and 94' above the adjacent shank portions 62' and 66' is 1/32 of an inch. The articulation of the blade members 12' and 14' with respect to the handles 18' and 20' permits the cutting surfaces 70' and 72' to be positioned in a grinding fixture with the pivot bolts 26', 40' and 42' in place, only the main pivot bolt 16' having been removed. ;As noted hereinabove, the cutting of the sheet material workpiece 22' is enhanced if the upper and lower cutting surfaces 70' and 72' are not exactly parallel with respect to the pivot bosses 92' and 94' but, instead, are angled slightly so as to establish progressive Interference as the blade members are closed. Although various amounts of interference may be used with similar effect, applicant prefers an angle of approximately 15 minutes on each of the cutting surfaces 70' and 72' so as to establish a total interference of approximately one-half a degree. This interference forces the blades tightly together during the latter part of the cutting stroke to ensure a shearing action; and the angle and offset desired is formed when the blade members ;/ ;12' and 14' are initially ground or subsequently reground to ;26 ;4U0B81 ;effect resharpening. ;Suitable locking means which can be engaged manually to prevent the cutting snips 10' from opening from the closed position is shown in FIGURE 11. The pivot bolt 40' is formed with a shoulder portion between the shank portion and the head portion. A lock strap 104' is pivotably mounted upon the pivot bolt 42' outside the laterally spaced side portions 44' and 46' of the upper and lower handles 18' and 20'. The free end of the lock strap 104' is notched in a side portion thereof so as to form a hook surface 106'. The lock strap 104' is moveable manually between the pivot bolt 40' and the handle pivot bolt 26' from a first position shown in FIGURE 10 which permits operation of the cutting snips 10' to a second position shown in FIGURE 11 which locks the cutting snips 10' in the closed position. In the second position, the hook surface 106' of the free end of the lock strap 104' is rotated into engagement with the shoulder portion of the pivot bolt 40' such that the lock strap 104' is held in compression by the omega spring 50'. The lock strap 104' may conveniently be released or engaged by the operator's thumb to permit one-hand operation. ;Although the cutting surfaces 70' and 72' of the blade members 12' and 14' are considerably offset from the pivot bosses so as to provide all-way offset snips capable of cutting small opposing circles of the order of about 2.0" to 2.5" diameters, a triangular notch or recess 110' may still be provided in the shank portion 66' of the lower blade member 14' in line with the path of the cut sheet material workpiece 22' passing above the forward portion 86' of the lower blade member 14'. The recess 110' aids in permitting the cutting snips 10' to cut right-hand as well as left-hand ;27 ;*• vwu y i <br><br>
Cuming cuts. It will be appreciated that both configurations of the cutting snips shown are particularly suited for straight and left-hand turning cuts, but that the improvement shown in FIGURES 10 to 19 also can cut equally as well in a right-hand turning cut, say in cases where a small circle or sharp curve is experienced in the opposite direction from the tool's normal orientation. Thus, the embodiment of FIGURES 10 to 19 permits right-hand turning cuts of almost 2.0" to 2.5" in diameter; consequently eliminating for all intensive purposes the need for separate cutting snips particularly adapted for right-hand turning cuts. <br><br>
Another feature of the cutting snips 10' is that the handles 18' and 20' are particularly convenient and adapted for applying force throughout the range of motion of the cutting blades 12' and 14'. Unlike conventional offset snips, the handle pivot bolt 26' is disposed close to the hand grips 32' and 34', but at the same time it Is about 1/4 inch closer to the pivot bolts 40' and 42' as compared to that of FIGURES 1 to 9. As a result, the angle formed between the hand grips 32' and 34' when the cutting snips 10' are in the open position shown in FIGURE 10 is greater than that of conventional snips, as well as that of FIGURES 1 to 9. With the pivot bolts 40' and 42' disposed closer to the pivot bolt 26', the angle between "imaginery toggle links" between the pivot bolt 26' and each of said pivot bolts 40' and 42' is preferably in the order of about 115 degrees to about 120 degrees, and more preferably about 117 degrees with the snips in a closed position. With such construction, a more powerful snips is achieved inasmuch as the center <br><br>
28 <br><br>
Z0888 1 <br><br>
point of the three piece "toggle" linkage arrangement more closely approaches dead center where the three pivot points would form a straight line (maximum power). <br><br>
In the open position, the forward portions of the hand grips 32' and 34' are spaced apart to permit the handles 18' and 20' to be spanned by the operator's hand adjacent the ear portions 36' and 38' for maximum leverage. The lower handle 20' 18 configured such that the open position of the lower hand grip 34' does not interfere with a work-bench upon which the sheet material workpiece 22' is placed for cutting. As the upper and lower blade members 12' and 14' are moved toward the closed position shown in FIGURE 11, the more rearward portions of the upper and lover hand grips 32' and 34' are progressively, Ideally spaced apart for maximum leverage. <br><br>
Of course, it should be understood that various changes and modifications to the preferred embodiments described above will be apparent to those skilled in the art. For example, rivets or other pivot means may be employed in place of the four bolts without affecting the operation of the cutting snips. It is therefore intended that the foregoing detailed description be regarded as Illustrative rather than limiting and that it be understood that it is the following claims, including all equivalents, that are intended to define the scope of this invention. <br><br>
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