FR2565516A1 - UNIVERSAL SHEAR WITH OFFSET WITH WIRE CUTTER OVER THE WIDTH - Google Patents

Abstract

A UNIVERSAL OFFSET SHEAR 10 WITH A THREAD CUTTER THROUGHOUT THE WIDTH HAS BOSSES THROUGH WHICH A FIRST AND A SECOND BLADE 12, 14 ARE PIVOTALLY CONNECTED TO ROTATE AROUND AN AXIS 16 PERPENDICULAR TO THE PIVOT BOSSES. THE BLADES HAVE CUTTING SURFACES 70, 72 DEPORTED FROM THE PIVOT BOSSES TO ALLOW THE CUTTING OF IRREGULAR SHAPES, INCLUDING TIGHT CURVES AND SMALL CIRCLES, UP TO 51 TO 64 MM IN DIAMETER. THE CUTTING SURFACES MAY ROTATE BETWEEN AN OPEN AND AN OPEN POSITION AND A CLOSED POSITION TO CUT THE SHEET BETWEEN THEM.

Description

i Universal offset shear with wire cutter on all

the width.

  The present invention relates to cutting pliers or an improved manual offset shear, which can be used

  for cutting metal sheets or similar materials

  res, either in a straight line, or to the right or to the left, including for making circular cuts

  up to an opposite circle of approximately 51 to 63.5 mm in diameter.

  When cutting metal sheets or similar materials

  With conventional shears, one or both edges of the cut sheet can encroach on the body of the shears, making it difficult for the shears to advance through the sheet and distorting the cut edges. This encroachment is very large when it comes to cutting irregular shapes, especially tight curves and especially small circles. Consequently, conventional shears are often supplied in two symmetrical configurations in a mirror, particularly suitable for making cuts, either turning to the left or turning

  on the right. Furthermore, when using shears

  optional to cut thick, stubborn or rigid materials, the sheet may tend to slide blades when they are closed, which reduces the efficiency of the cut. In addition, conventional shears may require long branches and significant force to be exerted by

  the user to cut most sheet metal products.

  As shown in US Patent No. 2,264,840, one approach to reducing the encroachment of the cut sheet on the body of the shears is to offset the cutting surfaces relative to the branches of the shears so that the cut sheet passes over one side of its branches. We also see in this patent the extension of the cutting blades

  laterally substantially at right angles to the

  branch operating rights. This configuration

  facilitates the advancement of the shears in the sheet by reducing

  the distance by which the cut sheet must be pushed vertically to pass above and below the lower blade, thus reducing the tendency of the sheet to slip away from the cutting surfaces. More recently, a connecting rod mechanism, as shown in US Patent No. 3,587,173, has been proposed to reduce the force required by the user

for cutting thick sheets.

  As in the case of conventional shears, most of the offset shears available can generally only be used to cut curves, either to the left or to the right, which requires other offset shears with a symmetrical configuration in a mirror

  when it comes to cutting curves in the other direction.

  In addition, the blades extending laterally from the available offset shears must be carefully ground and

  aligned during manufacture and generally they cannot

  may be properly ground again if they become dull or damaged. Damage to the blades when cutting wire or products

  similar can make the shear unusable for cutting

  per sheets. Consequently, a need exists for a

  improved offset shear, which can easily be

  sharpen if the blades are dull or damaged, and which

  includes a wire cutter of the clamp type or of the shear type.

  In addition, there is a need for an improved arrangement of branches and knee pads making the offset shear more powerful and more suitable when it comes to cutting

thick sheets.

  In a US patent application of the Applicant, a wire cutter of the clamp type is used, in which a part of the upper blade serves as an anvil and a part of the lower blade serves as a chisel for the wire cutter. In such an arrangement a "clearance" formed at the base of the elements of the thread cutter, due to the manufacturing process

  involved, requires that the wire to be cut be specifically positioned

  practically in the center in the thread cutter. If, for example, there is a small diameter metal wire at the

  level of the thread cutter base, the "clearance" prevents ef-

  fectively the wire to be cut by the chisel and the anvil.

  This "clearance" is created due to the various operations or grinding passes required to grind the opposite faces of the chisel. Furthermore, in the formation of the chisel

  this patent application, the grinding passes generally create

  a wide V-shaped chisel, the angle between

  the sides is about 70. Although suitable for most

  share of applications, such an angular configuration

  of the chisel requires more delicate manufacturing processes

  cats and therefore results in a significantly higher production cost. It also requires higher forces and pressures to cut the metal wires because the cutting angle of the chisel is less acute and wires of smaller and possibly larger diameters can easily catch on or be trapped at the base of the wire. wire cutter in the "clearance" area. It is therefore more difficult to cut the wire and we must manually reposition the wire in the center so that the scissor cuts or clamps like a pliers over the entire width of the wire, with the wire squarely trapped between the anvil and

  the full width of the face of the chisel.

  Another disadvantage of the Patent Application of the Deman-

  aforementioned deresse is that the lower blade, although

  tee, does not provide enough clearance for opposite circular cuts of very small diameters to be made. This drawback makes it necessary to manufacture and store both left-hand shears and

  protrusions on the right, because no offset shears are real-

  considered a universal type of shears capable of cutting in any direction, that is, straight ahead, right and left. It should be noted that, in most cases, cutting arcs, curves or circles up to about 51 to 64 mm in diameter satisfies most

requirements.

  It is therefore an object of the present invention to pro-

  to cure a universal shear with improved offset, which can cut sheets at the same time according to curves on the left and

  curves to the right, as well as circles of very small diameters

  very, without being bothered by the encroachment of the product

  cut with the body of the shears.

  It is another object of the present invention to provide a

  universal shear with improved offset greater power

  and in which the cutting surfaces can be-

  appropriately economical, tapered if these surfaces

  are dull or damaged, and in which the re-

  sharpening the wire cutter chisel can be done by a

  single grinding pass with the boss of its blade.

  It is another object of the present invention to provide a universal shear with improved offset having means, either of the cutting pliers type or of the shearing type, for cutting metal wires and the like, eliminating

  thus the need for a second tool and reducing damage

  Aged under the cutting surfaces of the blade sheets

deported.

  It is another object of the present invention to provide a universal shear with improved offset, the power of which is notably increased due to a toggle mechanism which provides greater force on the central toggle pivot of a mechanism. toggle with two connecting rods and three pivot points, since the pivot points of the toggle joint are generally aligned when

  the offset shear is in the closed position.

  It is another object of the present invention to provide a universal offset shears having branches with

  a toggle mechanism for exercising power

  significantly larger, branches that can be more easily grasped when the shears are in the open position

  and more easily force back to the closed position.

  It is yet another object of the present invention to pro-

  clean a universal offset shear having a wire cutter of the type, either cutting pliers or shearing, with the anvil portion of the pliers on the upper blade and the chisel on the lower blade, whatever the type of

employee wire cutter.

  It is yet another object of the present invention to provide

  rer a universal offset shears having a chisel which can be sharpened in a single grinding pass with the boss of its blade and which cuts across the entire width of the anvil. The present invention relates to improvements in pliers or manual universal shears with wire cutting means across the entire width for cutting sheet metal and wire or the like.

produced in the form of rods.

  According to one aspect of this invention, first and second blades have pivot bosses through which a pivot pivotally connects the blades to allow them to rotate about an axis perpendicular to the pivot bosses. The respective blades have a first cutting surface and a second cutting surface which are offset

  relative to the plane of the respective pivot bosses. When-

  as the blades rotate around their pivots, the first

  cutting surface and the second cutting surface are displaced

  created between an open position and a closed position to cut sheet metal between them. The pivot bosses and

  cutting surfaces are adapted so that it can be removed

  worm of the material so as to be able to re-sharpen the cutting surfaces while maintaining the offsets between the pivot bosses and the respective cutting surfaces. While re-sharpening the thread cutter chisel, a pivot boss

  is also ground to bring it back to the desired size.

  The offsets of the cutting surfaces from the pivot bosses are at a minimum of approximately 6.35 to 9.5 mm, so as to allow the product cut previously to pass to the

  straight blades without encroachment and to allow effect

  kill opposite circular cuts of very small diameters.

  According to another aspect of this invention, a first blade

  and a second blade are pivotally connected by the

  intermediate of body portions, one of the body portions having a recess practically in the plane of the sheet to be cut. The respective blades have a first cutting surface and a second cutting surface whose offsets with respect to the body portions are extended and which can move by turning between an open position and a closed position to cut sheet metal therebetween. A cut edge of the cut sheet can be housed in the recess so as to allow the sheet to be cut at the same time according to curves turning to the left or turning to the right.

  that the offset shear of the present invention is "uni-

  verselie ", effectively eliminating the need for separate shears to the right and left when cutting

irregular are necessary.

  According to another aspect of the invention, the branches can

  rotate to provide leverage

  particularly favorable throughout the cutting stroke,

  whereby the center point of the kneepad around the

  what forces are created to get a lock

  powerful tool is obtained by positioning it practical-

  in line just beyond the "dead center overhang" position of the toggle joint, with the pivot bolts providing the articulated movement of the blades relative to the branches. Other aspects of the invention include improved one-piece cutting means, suitable for cutting metal wires and one-piece locking means

  to keep the cutting blades in the closed position.

  The invention will be better understood on reading the description.

  detailed description, given below by way of example only, of several preferred embodiments, in conjunction with the accompanying drawing, in which:

  - Figure 1 is a side elevational view of a reali-

  sation of the offset shears of the present invention, shown in the open position, with parts torn off; - Figure 2 is a side elevational view of the offset shear of Figure 1, shown in the closed position or cutting position, with parts broken away; - Figure 3 is a sectional view of the offset shears of Figures 1 and 2, taken along line 3-3 of Figure 2; - Figure 4 is a side elevational view of the upper cutting blade of the offset shears of Figures 1 to 3;

  - Figure 5 is a sectional view of the upper cutting blade

  lower of the offset shears of Figures 1 to 3, taken along line 55 of Figure 4;

  - Figure 6 is a sectional view of the upper cutting blade

  lower of the offset shears of Figures 1 to-3, taken along line 66 of Figure 4; - Figure 7 is a side elevational view of the lower cutting blade of the offset shears of Figures 1 to 3;

  - Figure 8 is a sectional view of the lower cutting blade

  lower of the offset shears of Figures 1 to 3, taken along line 88. of Figure 7;

  - Figure 9 is a sectional street of the lower cutting blade

  lower of the cutting shears of Figures 1 to 3, taken along line 99 of Figure 7;

  - Figure 10 is a side elevational view of a reaction

  preferred reading of the offset shears of this

  invention, shown in the open position, with holders

torn off;

  - Figure 11 is a side elevational view of the above

  offset projection of Figure 10, shown locked in the closed position or cutting position, with parts torn off; - Figure 12 is a sectional view of the offset shears of Figures 10 and 11, taken along line 12-12 of Figure 11; - Figure 13 is a side elevational view of the upper cutting blade of the offset shears of Figures 10 to 12;

  - Figure 14 is a sectional view of the upper cutting blade

  lower of the offset shears of Figures 10 to 12, taken along line 14-14 of Figure 13; - Figure 15 is a sectional view of the upper cutting blade of the offset shears of Figures 10 to 12, taken along line 15-15 of Figure 13; - Figure 16 is a side elevational view of the lower cutting blade of the offset shears of Figures 10 to 12;

  - Figure 17 is a sectional view of the lower cutting blade

  lower of the offset shears of Figures 10 to 12, taken along line 17-17 of Figure 16;

  - Figure 18 is a sectional view of the lower cutting blade

  lower of the offset shears of Figures 10 to 12, taken along line 18-18 of Figure 16; and - Figures 19A and 19B are partial top views

  opposite shear blades of wire cutter to a shear-

  ment that one can, if desired, use in place of

pliers type wire cutters.

  Reference is now made to the drawing in which FIGS. 1 to 3 represent an embodiment of an offset shear produced according to the present invention and marked as a whole at 10. The shears 10 comprise an upper blade

  marked as a whole at 12 and a lower blade marked

  as a whole in 14, which blades can be

  pivotally moved around a main pivot bolt

  cipal 16 by the action of an upper branch identified as a whole in 18 and a lower branch identified in

  as a whole in 20. The rear portions 28 and 30 of the branches

  ches 18 and 20 respectively are covered with a handle

  upper 32 and lower handle 34 respectively.

  Preferably, the handles 32 and 34 are formed by immersion

  or by molding so as to present ear flaps projecting outwards, respectively 36 and 38, so as to prevent the user's hand from sliding towards

  the front when using the cutting shears 10.

  The preferred material for handles 32 and 34 is applicable by hot immersion, such as that sold by

  Sinclair Rush, St. Louis, Missouri.

  The branches 18 and 20 extend forward from the pivot bolt of the branches 26 and they separate from one another to be articulated on the blades 12 and

  14 by pivot bolts 40 and 42 respectively.

  In the open position shown in Figure 1, a

  acute angle is preferably formed between a line ima-

  ginary connecting the pivot bolts 26 and 40 and an imaginary line connecting the pivot bolts 26 and 42. Preferably, the cross section of the branches 18 and 20 is U-shaped, as seen in Figure 3, this U being formed by laterally spaced lateral portions 44 and 46 connected by a core 48. An omega spring

  held in place by the branch pivot bolt

  ches 26 cooperates with the core 48 of the branches 18 and 20 for

  return the cutting shears 10 to the open position.

  Other recall means can be used for a similar purpose. A ring 51 is disposed between the pivot bolt of the branches 26 and the omega spring 50 to center

  the spring 50 and the space between the pivot pivot bolt

  ches 26. Although the ring 51 is not essential for the operation of the cutting shears 10, it has been found that it considerably prolongs: spring life

Omega 50.

  In the open position, the upper blade 12 extends towards

  up and back from the main pivot bolt

  pal 16 to a pivoting joint on the bolt

  pivot 40, as seen in Figure 1. The lower blade

  14 extends backwards from the main pivot bolt 16 to a pivoting joint on the pivot bolt 42. In response to the closure of the arms 18 and 20, the pivot bolts 40 and 42 rotate around the 1 1 pivot bolt of the branches 26, thus spacing the rear portions 54 and 56 of the blades 12 and 14. As can be seen in FIG. 3, the rear portions 54 and 56 are thick enough to be fitted tightly between the lateral portions 44 and 46 of the branches 18 and 20 so as to keep the upper cutting blades 12 and lower 14 aligned. The clearance between the lateral portions 44 and 46 and the rear portions 54 and 56 is carried out by means of nuts. adjustment 58 screwed on pivot bolts 40

and 42.

  The main pivot bolt 16 is screwed into a hole 60 in the central portion or body 62 of the upper blade 12 and forms a sliding fit with a hole 64 in the central portion or body 66 of the lower blade 14. A locking nut 68 is locked against the body 62 to maintain the adjusted length of the main pivot bolt

  16. The cutting surfaces 70 and 72 of the cutting blades remain

  pectives 12 and 14 lie in a plane practically parallel to the adjacent bodies 62 and 66 of the respective blades, but they are offset laterally, as can be seen in FIG. 3. It will be noted that this offset is sufficient to allow a cut portion from sheet 22 to pass on

  the side of the body portion 66.

  It has been found that the cutting of the sheet 22 is improved if the cutting surfaces 70 and 72 are, in side elevation, curved, as seen in Figures 4 and 7, so

  to present cutting surfaces to the cutting sheet

  offended. In the preferred embodiment shown, the upper cutting surface 70 is defined by a radius of approximately centimeters, and the lower cutting surface 72 is

  also defined by a radius of about 20 centimeters.

  However, the configuration shown is given by way of illustration only, since various other curved configurations can be used with similar results. As shown clearly in FIGS. 4 to 8, the front portions 84 and 86 of the respective blades 12 and 14 extend laterally almost perpendicular to the body portions 62 and 66. This configuration facilitates the cutting of a sheet 22 which is placed on a flat surface such as a table and further minimizes the distance from which the cut surfaces of the sheet must be kept apart as they pass

  above and below the lower blade 14.

  Preferably, the blades 12 and 14 are recessed ground along the surfaces 78 and 80 respectively to ensure that the upper cutting surfaces 70 and lower 72 have a uniform width in lateral elevation, while allowing the blades to be resharpened as it will be described

  below. The rear portion of the lower cutting surface

  72 has a clearance 82 to facilitate the furnishing

  lage of the cutting surface 72 and to ensure during cutting cooperation by gentle sliding of the cutting surfaces 70 and 72. The front portions 84 and 86 of the blades 12 and 14 are curved inwardly, as seen

  in Figures 6 and 9, to form convex surfaces.

  This configuration of the front portions 84 and 86 gives the

  cutting surfaces 70 and 72 sufficient mechanical resistance

  health, while allowing to easily maneuver the shears

  cutting 10 for cutting purposes, when space is limited.

  The cutting of a wire 24 is obtained by the cooperation of an anvil 88 formed on the upper blade 12 with a chisel or wedge-shaped portion 90 formed on the lower blade 14. The arrangement of the anvil 88 and the wedge-shaped portion 90 is such that their cooperation forms a stop to limit the rotation of the blades when the cutting shears 10 is in the closed position shown in FIG. 2. The wedge-shaped portion 90 serves as a chisel for cutting a wire, a rod, a small bar or the analog, placed on the anvil

  88 when the cutting shears 10 is moved from the posi-

  open position shown in Figure 1 at the closed position

  mée of figure 2. It will be noted that, instead of the anvil 88 and the wedge portion 90, it is possible to use with a similar result other opposite cutting surfaces.

  such as for example those of diagonal thread cutters.

  It is an important feature of the present invention that cutting surfaces 70 and 72 can be ground again to renovate worn or damaged cutting surfaces. Referring to Figure 3, it appears that a new grinding, either of the upper cutting surface

  70, i.e. from the lower cutting surface 72, would create nor-

  improperly a lateral space between these cutting surfaces 70 and 72, thus preventing the shearing of the sheet 22. The offset of the cutting surface 70 relative to the body portion 62 is reduced by such grinding, and the offset of the cutting surface 72 relative to the body portion 66 is increased by such grinding. For this reason, commercially available offset shears cannot be resharpened properly when they are dull or

have been damaged.

  The resharpening of the cutting shears 10 of the present invention is facilitated by pivot bosses, generally identified at 92 and 94, on the adjacent surfaces of the respective body portions 62 and 66. The pivot bosses 92 and 94 are flat projections above the surface of the body portions 62 and 66, perpendicular to the main pivot bolt 16. The pivot boss 92 need not have a particular shape, but, as

  example, it may include a semi-anterior portion

  circular 96 concentric to the main pivot bolt! 6 and a rectangular rear portion 98, as seen in FIG. 4. Similarly, by way of example, the boss

  pivot 94 may have a semi-anterior portion

  circular 100 concentric with the main pivot bolt 16 and a triangular rear portion 102, as shown in FIG. 7. The pivot bosses 92 and 94 provide improved bearing surfaces between the blades 12 and 14, while

  maintaining the alignment of the cutting surfaces 7% and 72.

  The posterior portions 98 and 102 cooperate to prevent the cutting surfaces 70 and 72 from moving apart during the

cutting stroke.

  In the cutting shears 10, the offset of the cut surfaces

  Pants 70 and 72 is determined by the location of the bosses

  pivot 92 and 94. As a result, it is possible to carry out a

  sharpening the shears 10 by grinding both the cutting surfaces 70 and 72 and the respective pivot bosses 92 and 94. It will be noted that there is no modification of the offset of the upper cutting surface 70 if an equal ground is ground thickness of material both on the upper cutting surface 70 and on the pivot boss 92. Similarly, the offset of the lower cutting surface 72 will not be modified if equal thicknesses of material are ground on both the cutting surface lower 72 and on the pivot boss 94. Thus, one can re-sharpen at will one or the other, or the two blades 12 and 14, without creating a space

  lateral between the cutting surfaces 70 and 72.

  Re-sharpening the respective blades is further simplified because no curved surface requires further grinding. The upper and lower cutting surfaces, 70 and 72, are ground in a plane which is practically parallel to the respective pivot bosses 92 and 94. The pivot bosses 92 and 94 can be machined first to provide

  reference surfaces for grinding of coated surfaces

  Pantes 70 and 72. The recessed ground portions 78 and 80 of the respective blades 12 and 14 eliminate the need for grinding of any other surface during re-sharpening. It was found that there was sufficient resharpening potential if the height of the pivot bosses 92 and 94 above the

  adjacent body portions 62 and 66 was 0.8 mm. The arti-

  culation of the blades 12 and 14 relative to the branches 18 and makes it possible to position the cutting surfaces 70 and È in a grinding device with the pivot bolts 26, and 42 in place, only the main pivot bolt 16

to be removed.

  It has been found that the cutting of the sheet 22 is improved if the upper and lower cutting surfaces, 70 and 72, are not exactly parallel to the pivot bosses 92

  and 94, but that they are slightly tilted so as to be

  blir a progressive encroachment when the blades are closed. Although varying degrees of encroachment can be used

  with a similar result, we prefer an angle of approx.

  For 15 minutes on each of the cutting surfaces 70 and 72 so as to establish a total encroachment of about half a degree. This encroachment strongly applies the blades to each other during the last part of the cutting stroke to ensure a shearing action. The desired angle and offset can be set appropriately economically when the blades 12 and 14 are initially ground or are

  subsequently ground again to re-sharpen.

  Note that the grinding of the pivot bosses 92 and 94 is only a simple illustration of the concept of the invention consisting in removing material from the adjacent body portions 62 and 66 of the upper blade 12 and the lower blade 14 to allow the resharpening of the cutting surfaces 70 and 72. Instead of grinding, it is also possible to use milling means or other cutting means provided that these cutting means are not counter-square

by the hardness of the blades 12 and 14.

  Another characteristic resides in the locking means.

  lage which can be set up manually to prevent the shears 10 from opening from the fence position shown in Figure 2. The pivot bolt 40 has a shoulder between the barrel and the head. A locking strip 104 is pivotally mounted on the pivot bolt 42, outside the laterally spaced side portions 44 and 46 of the

  upper and lower branches 18 and 20. A lateral portion

  part of the free end of the locking strip 104 is notched to form a latching surface 106. The locking strip 104 can be moved manually between the pivot bolt 40 and the branch pivot 26 from a first position shown on Figure 1, which allows the operation of the shears 10, to a second position shown in Figure 2, which locks the shears 10 in the closed position. In the second position, the hooking surface 106 of the free end of the locking strip 104 is brought into engagement with the shoulder J of the pivot bolt 40 so that the locking strip 104 is kept compressed by the omega spring. 50. Suitably, the locking strip 104 can be released

  by the user's thumb to allow operation

with one hand.

  Another important characteristic of the shears 10 is that a triangular notch or recess 110 is formed in the body portion 66 of the lower blade 14 in

  alignment with the path of the cut sheet 22 passing through

  above the front portion 86 of the lower blade 14.

  The recess 110 allows the shears 10 to make cuts turning to the right as well as cuts turning to the left. It will be noted that the configuration of the shears 10

  shown in the preferred embodiment is particularly suitable

  straight to straight cuts or to cuts turning to the left. However, it has been found that the recess allows cuts turning to the right with a diameter equal to or greater than 10 centimeters, thus eliminating

  the need to have a separate separate shear-

  suitable for right-turning cuts. We can pre-

  see similar shears with a symmetrical configuration

  stick in a mirror, which would be particularly appropriate

  required to make straight cuts or right-turning cuts, but still capable of making

  cuts turning left with a diameter of 10 centimeters.

  Another important characteristic of the shears 10 is that the branches 18 and 20 are particularly suitable

  for applying a force over the entire displacement range

  cementing of the blades 12 and 14. Unlike most conventional offset shears, the pivot bolt of the branches 26 is relatively close to the handles 32 and 34. As a result, the angle formed between the handles 32 and 34, when the shears 10 is in the open position shown in Figure 1, may be greater than that of a conventional shears. In the open position, the

  front portions of handles 32 and 34 are spaced apart for

  put in the user's hand to grasp the branches 13

  and 20 in the vicinity of the atria 36 and 38 so as to have

  use maximum leverage. The lower branch 20 has a configuration such that the open position of the lower handle 34 does not encroach on a workbench on which the sheet 22 is placed for cutting purposes. When the upper and lower blades 12 and 14 are moved to the closed position shown in FIG. 2, the rearmost portions of the upper 32 and lower handles 34 are progressively ideally spaced to have the maximum lever power. In addition, the blades 12 and 14 and the branches 18 and 20 constitute a four-bar connection system, which amplifies the transmission of the force applied manually to the cutting surfaces 70 and 72 to

  reduce user effort and fatigue.

  A variety of materials can be used to form the blades and branches depending on the material of the sheet to be cut. In the preferred embodiments shown, the cutting blades are forged from tool steel alloy and are ground to the configurations shown. Such an embodiment gives sufficient mechanical strength to

  allow the shear to cut steel sheets. However

  However, other materials and less costly forming methods can be used, especially when smaller sheets have to be cut. Branches 18 and 20 can

2565516.

  suitably and economically be made of mild steel and be formed by various stamping operations. The locking strip 104 may also, suitably and

  economical, be formed from sheet steel.

* We now refer to Figures 10 to 19, on which we see a universal shear with improved offset with an improved wire cutter, identified as a whole in 10 '. The shear 10 'comprises an upper blade 12' and a lower blade 14 ', which can be pivotally displaced around a main pivot bolt 16' by upper, 18 'and lower 20' branches. The movement of the blades 12 'and 14' between the open position shown in Figure 10 and the closed position shown in Figure 11 it cuts a sheet metal part 22 'or a metal wire part 24' disposed between blades 12 'and 14',

as seen in Figure 10.

  The branches 18 'and 20' can pivot around a branch pivot bolt 26 'disposed between the ends of the branches 18' and 20 '. The rear portions 28 ′ and 30 ′ of the respective branches 18 ′ and 20 ′ are covered by

  upper and lower handles, 32 'and 34' respectively.

  Preferably, the handles 32 'and 34' are formed by immersion in molding so as to have ears projecting outwards 36 'and 38' respectively to prevent the user's hand from sliding forward

  when using the 10 'shears.

  The branches 18 'and 20' extend forward from the branch pivot bolt 26 'away from one another to be pivotally articulated on the blades

  12 'and 14' by pivot bolts 40 'and 42' respectively.

  In the open position shown in Figure 10, an acute angle is preferably formed between an imaginary line

  connecting the pivot bolts 26 'and 40' and an imaginary line

  nary connecting the pivot bolts 26 'and 42'. Such an acute angle is of the order of approximately 70 in the two embodiments of the invention. However, in the closed position, this angle between the two imaginary lines of the same length is preferably increased from about 10 to about 15 (114 to 119), which results in a significantly more powerful grip because the toggle mechanism is shallower and that the pivot points of the toggle joint are generally aligned when the offset shear is in the closed position. With the pivot bolts 40 'and 42' closer to the branch pivot bolt 26 ', the latter is much closer to neutral when the power is maximum

  for the toggle mechanism. So in this realization

  sation of the invention, the distance between the pivot bolt

  of branches 26 'and the pivot bolt 40' and 42 'is of

  about 6.3 millimeters lower, which results in an improved offset shear having a power

  considerably higher than that of the illustrated embodiment

  felt in Figures 1 to 8. Here, in the closed position, the two opposite equal angles of the knee mechanism of the triangular dead center protrusion type form angles with the other imaginary line connecting the bolts

  pivot 40 'and 42' on the order of about 30 to about 33.

  Preferably, the cross section of the branches 18 'and' has the shape of a U, as seen in FIG. 12, formed by laterally spaced lateral portions 44 '

  and 36 'connected by a 48' core. An omega 50 'spring, main-

  held in place by the branch pivot bolt 26 ', is

  in engagement with the blade 48 'of the branches 18' and 20 'for rapp-

  the 10 'shears in the open position. One can also use other return means with this embodiment of the invention, and, although the centering ring 51 'is not essential to the operation of the shears 10', this ring 51 'significantly prolongs the service life of

omega 50 'spring.

  In the open position, the upper blade 12t extends upward and backward from the main pivot bolt 16 'to a pivot joint on the pivot bolt 40', as seen in the figure 10. The lower blade 14 'extends rearwards from the bolt

  main pivot 16 'to a pivot joint-

  on the pivot bolt 42 '. In response to the branches 18 'and 20' being closed, the pivot bolts 40 'and 42' rotate around the branches pivot bolt 26 ', spreading

  thus the rear portions 54 'and 56' of the blades 12 'and 14'.

  As shown in FIG. 12, the rear portions 54 ′ and 56 ′ have a thickness sufficient to be accommodated

  tightly between the lateral portions 44 'and 46' of the branches

  ches 18 'and 20' so as to keep the upper 12 'and lower 14' cutting blades aligned. The adjustment of the clearance between the lateral portions 44 'and 46' and the rear portions 54 'and 56' is obtained by means of adjustment nuts

  58 'screwing onto the pivot bolts 40' and 42 '.

  The main pivot bolt 16 'is screwed into a hole 60' in the central portion or body portion 62 'of the upper blade 12' and forms a sliding fit with a hole

  64 'in the body portion 66' of the lower blade 14 '.

  A locking nut 68 'is locked against the body portion 62' to maintain the adjusted length of the main pivot bolt 16 '. Cutting surfaces 70 'and 72' of the respective cutting blades 12 'and 14' lie in a plane practically parallel to the adjacent body portions 62 'and 66' of the respective blades, but are offset laterally as seen on the Figure 13. It should be noted that the offset in this embodiment of the invention is sufficiently extended to allow a cut portion of a sheet 22 'to pass easily over the side of the body portion 66', but, which is more importantly, to allow the improved tool to cut to an opposite circle of approximately 51 to 63.5 millimeters in diameter. This arrangement makes it possible to cut sheet metal in most cases with a single tool in the sense that the extended offset blades allow not only straight linear cuts, but also cuts

  in a tight curve either to the left or to the right.

  In this preferred embodiment of the invention, the cutting surfaces 70 ′ and 72 ′ are also curved in lateral elevation, with identical radii, as can be seen in FIGS. 13 and 16, so as to present to the workpiece to be cut convex cutting surfaces. Furthermore, the anterior portions 84 'and 86' of the respective blades 12 'and 14' extend laterally almost perpendicular to the body portions 62 'and 66', as in the embodiments

Figures 1 to 9.

  Preferably, the blades 12 'and 14' are recessed 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 lateral elevation while allowing re-sharpening the blades as will be described below. The rear portion of the lower cutting surface 72 'has a recess 82' to facilitate the grinding of the cutting surface 72 'and to ensure smooth sliding cooperation of the cutting surfaces 70' and 72 'during cutting. The front portions 84 ′ and 86 ′ are curved inwards as seen in FIGS. 15 and 18, to form convex surfaces. This configuration of

  front portions 84 'and 86' provide mechanical resistance

  sufficient for cutting surfaces 70 'and 72' while allowing the shears 10 'to be easily maneuvered for

cuts when space is limited.

  The cutting of the metal wire 24 'is obtained by the cooperation of an anvil portion 88' formed on the lower blade 14 'and a chisel or wedge-shaped portion 90' formed on the upper blade 12 '. The layout of the anvil portion 88 '

  and of the wedge portion 90 ′ is such that their cooperation

  tion provides a stop to limit the rotation of the blades

  when the shear 10 'is in the closed position shown

  felt in Figure 11. The wedge-shaped portion 90 'serves as a chisel to cut a wire, a rod, a small bar or the like placed on the anvil portion 88' when the shears 10 'is moved from the open position. shown in Figure 10 in the closed position of Figure 11. Note that the opposing cutting surfaces cut the wire in the manner of a cutting pliers, which is preferable to other cutting means such as shear cutting ,

  in the sense that a separate limit stop is not necessary.

  With shear cutting surfaces in the form of cutting blades like scissors between opposite blade portions, the shears would also require a pair of associated stops 89 and 91 (limiting stops) between the branches to limit the rotation of the blades (as seen in phantom in Figures 10 and 11). Such a limiting stop is necessary in each of the embodiments of FIGS. 19A and 19B, where the wire cutter of the cutting pliers type has been replaced by a wire cutter of the shear type. With a shear type wire cutter according to FIG. 19A, the anvil portion 88 ′ is simply ground to release the chisel 90 ′ and the displacement of the chisel 90 ′ (shown in dashes) in line with the opposite shear edge 93 'cut the wire (shown in phantom). In FIG. 19B, the opposite shear edge 93 'is offset towards the outside, because the acute cutting edge of the chisel 90' is arranged at an angle opposite to that of the chisel 90 '

of Figure 19A.

  With wire cutters such as wire cutters or with a wire cutter

  wire of the shear type, no recess is necessary at the base of the cutting elements, since the edges of the chisel are all sharpened by grinding across the entire width of the cutting elements. With the improved shears of the invention, a single grinding pass is necessary to form either type of wire cutter, since the cutting elements are formed by grinding a beveled edge from an edge straight. Thus, a knife edge or shear blade formed in this way can have a significantly smaller angle and therefore be much sharper than a wire cutter of the pliers type having a more conventional obtuse V angle. For example, an angle of about 70 is provided in the chisel of Figures 1 to 9, while in the preferred embodiment, an angle of about

  at around 60 is satisfactory. It is believed that a scrub

  considerably lower is created when cutting

  with the sharper knife of the present invention, for example

  parison with the wire cutter of the anterior cutting pliers type.

  In these cases, the blades are intrinsically made of stronger steel to maintain a cutting edge or sharper cutting edges. Preferably, we have found that

  angle of about 50 suited to the implementation of the in-

  vention. It should also be noted that, with an obtuse angle of for the wire cutter of the V-shaped cutting pliers type of FIGS. 1 to 9, the forces required to cut the metal wires are higher, because the chisel having the shape of a wider corner creates more friction resistance

important to the cut.

  It should be noted that, with the wire cutters over the entire width of the face of the present invention, it is easy to cut very small wires, since there is no "clearance" at the base of the knives. Thus, the small wire can be placed anywhere along the cutting edge or the anvil, whether it is a wire cutter of the cutting pliers type or of the shear type, without fear that this small wire is hooked in a "clearance" at the base of the knife or anvil

  and is not cut or incomplete. In that case,.

  we must then precisely reposition the wire in the center of the wire cutter in order to cut the wire in another place, or finish the incomplete cut in the same place, or cut as close as possible to the first attempt, which we

  cannot reasonably be achieved without the help of special tools

  cials to precisely align the thread cutter for

"second cut" at the wire.

  It is an important feature of the present invention that the cutting surfaces 70 'and 72' can be ground

  again to renovate worn or damaged cutting surfaces

  damaged. Referring to Figure 12, it appears that a new grinding, is the upper cutting surface 70 '

  either from the lower cutting surface 72 ', should normal-

  ment create a lateral space between the cutting surfaces 70 'and 72', thus preventing the shearing of the sheet 22 '. The offset of the cutting surface 70 'relative to the body portion 62' is reduced by such grinding and the offset of the cutting surface 72 'relative to the body portion 66' is increased by such grinding. For this reason, as noted above, the available offset shears

  in the trade cannot be resharpened appropriately

  requested once they have been dull or damaged.

  The resharpening of the shears 10 'of the present invention is facilitated by pivot bosses, generally marked at 92' and 94 'on the adjacent surfaces of the body portions 62' and 66 'respectively. The pivot bosses 92 'and 94' are flat projections above the body portions 62 'and 66', perpendicular to the main pivot bolt 16 '. In the preferred embodiment, the pivot boss 92 'has a particular shape, in that it comprises a portion 96' generally concentric with the main pivot bolt 16 'and a portion rising upward 97 in the form of a narrow rectangle, as seen in Figure 13. The pivot boss 94 'has a generally cylindrical portion 100' concentric with the bolt

  main pivot 16 'and a generally extending portion

  up 101, as shown in Figure 16.

  The pivot bosses 92 'and 94' provide surfaces of

  improved range between 12 'and 14' blades, while maintaining

  nant the alignment of the cutting surfaces 70 'and 72'. The por-

  upward oriented positions 97 and 101 also strengthen

  respectively the mechanical resistance of the portion of

  anvil 88 'as well as the scissor 90' itself.

  In the shear 10 ', the offset of the cutting surfaces 70' and 72 'is determined by the location of the pivot bosses 92' and 94 '. As a result, the shears can be re-sharpened by grinding both the cutting surfaces 70 'and 72' and the respective pivot bosses 92 'and 94' (as well as their upward-facing portions 97 and 101 ). Note that no change occurs in the offset of the upper cutting surface 70 ′ if equal thicknesses of material are ground on the upper cutting surface 70 ′ and on the pivot boss 92 ′. Likewise, there is no change in the offset of the lower cutting surface

  72 'if equal thicknesses of material are ground on the

  lower cutting face 72 'and on the pivot boss 94'.

  Thus, one or the other of the blades 12 'and 14', or both,

  can be re-sharpened as required from time to time

  re during normal use, without creating a space

  lateral between the cutting surfaces 70 'and 72'.

  The resharpening of the respective blades is further simplified

  because no curved surface requires further grinding.

  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 bosses of

  swivel 92 'and 94' can be machined first to provide

  rer reference surfaces for grinding surfaces 'and 72'. The recessed ground portions 78 'and 80' of the respective blades 12 'and 14' eliminate the need for

  grind any other surface when resharpening. We have cons-

  a sufficient grinding potential is obtained if the height of the pivot bosses 92 'and 94' above the

  adjacent body portions 62 'and 66' is equal to 0.8 mm.

  The articulation of the blades 12 'and 14' relative to the branches 18 'and 20' makes it possible to position the cutting surfaces 70 'and 72' in a grinding tool with the pivot bolts 46 'and 42' in place, alone the main pivot bolt

16 'to be removed.

  As previously noted, the section of the sheet 22 '

  is improved if the upper and lower cutting surfaces

  lower, 70 'and 72', are not exactly parallel to the pivot bosses 92 'and 94', but on the contrary are slightly inclined so as to establish a progressive encroachment when the blades are closed. Although we can

  use different degrees of encroachment with identical results

  ment, an angle of about 15 minutes is preferred on each of the cutting surfaces 70 'and 72' so as to establish a total encroachment of about half a degree. This encroachment forces the blades tightly against each other during the last part of the cutting stroke in order to ensure a good shearing action; the desired angle and offset

  are formed when the blades 12 'and 14' are initially ground

  or are further ground again for

resharpening.

  Figure 11 shows a suitable locking means which can be operated manually to prevent the shears 10 'from opening from the closed position. The bolt of

  pivot 40 'has a shoulder between the barrel and the head.

  A locking strip 104 'is pivotally mounted on the pivot bolt 42' outside the laterally spaced side portions 44 'and 46' of the upper and lower legs 18 'and 20'. A lateral portion of the free end of the locking strip 104 ′ is notched so

  to form a hooking surface 106 '. The locking strip

  lage 104 'is moved manually between the pivot bolt 40' and the branch pivot bolt 26 'from a first position shown in Figure 10 which allows to use the cutting shears 10' to a second position shown in the Figure 11, which locks the shears 10 'in the closed position. In the second position, the attachment surface 106 ′ of the free end of the

  locking strip 104 'is engaged with the shoulder

  lement of the pivot bolt 40 ', so that the locking strip 104 is kept compressed by the omega spring 50'. The locking strip 104 'can suitably be released by the thumb of the user to

  allow use with one hand.

  Although the cutting surfaces 70 'and 72' of the blades 12 'and

  14 'are considerably offset from the bossa-

  pivot pins to provide a universal shear to

  offset capable of cutting small opposite circles of gold

  about 51 to 64 mm in diameter, a notch or hollow

  triangular ment 110 'can be provided in the body portion 66' of the lower blade 14 'in alignment with the path of the cut sheet 22' passing above the front portion 86 'of the lower blade 14'. The recess 110 'facilitates cutting to the right as well as cutting to the left. Note that the two shear configurations shown are particularly suitable for

  straight or left-hand cuts, but the am-

  improvement shown in Figures 10 to 19 also allows a cut turning to the right, for example in the case where a small circle or a tight curve must be cut

  in the opposite direction to the normal orientation of the tool.

  Thus, the embodiment of Figures 10 to 19 allows cuts turning to the right of almost 51 to 64 mmn in diameter, which eliminates the need for a separate cutting shears particularly suitable for cuts

turning right.

  Another characteristic of the shears 10 'is that the branches 18' and 20 'are particularly suitable and

  adapted to exert force over the entire displacement range

  cementing the cutting blades 12 'and 14'. Unlike conventional offset shears, the branch pivot bolt 26 'is placed very close to the handles 32' and 34 ', but at the same time it is about 6.3 mm closer to the pivot bolts 40' and 42 ', compared to the embodiment of Figures 1 to 9. As a result, the angle formed between the

  handles 32 'and 34', when the shear 10 'is in the posi-

  tion open shown in Figure 10, is greater than that of a conventional shears, as well as that of the shears of Figures 1 to 9. With the pivot bolts

  'and 42' arranged closer to the pivot bolt 26 ', the an-

  The gap between the "imaginary toggle links" between the pivot bolt 25 'and each of the pivot bolts 40' and 42 'is preferably in the range of about 115 to about, and preferably about 117 when the shears is in the closed position. With such an embodiment, a more powerful shear is obtained provided that the central point of the three-piece toggle mechanism is closer to neutral when the three pivot points are aligned (maximum power). '

  In the open position, the anterior portions of the poi-

  gnées 32 'and 34' are separated to allow the user's hand to grasp the branches 18 'and 20' in the vicinity of the atria 36 'and 38' to have the maximum leverage. The lower branch 20 'has a shape such that the open position of the lower handle 34' does not encroach on the workbench on which the sheet 22 'is placed

  for cutting purposes. When the upper and lower blades

  lower 12 'and 14' are moved in the direction of the closed position shown in Figure 1, the rearmost portions of the upper and lower handles 32 'and 34' are gradually ideally spaced to have

maximum leverage.

  It is understood that various changes and modi

  Fications to the preferred embodiments described above will be apparent to those skilled in the art. For example, instead of the four bolts, rivets or other pivoting means can be used without affecting the operation of the

  shear. It is therefore intended that the description

  detailed previous is only considered as an illus-

  tration and it is understood that these are the claims

  which define the scope of this invention.

Claims (12)

Claims.   1. Universal offset shear (10) for cutting metal wires (24) and for cutting metal sheets (22) or the like in practically any direction, having   upper (12) and lower (14) blades having respective-   first and second flat pivot bosses (92, 94) and first and second cutting surfaces (70, 72) offset from the plane of the first and second pivot bosses, and pivot means (16 ) pivotally connecting the upper blade and the lower blade to allow them to rotate about an axis perpendicular to the first and second pivot boss by means   opposite branches (18, 20) pivoting the upper blades   lower and lower around these pivot means so that the first and second cutting surfaces can be moved between an open position and a position   closed to cut characteristic metal sheet between them   ridged in that it comprises: a portion: extending upwards from the first pivot boss forming a beveled scissor edge (90) of a wire cutter, and the first cutting surface being simultaneously adapted so that material can be removed at the same time as this chisel edge is sharpened, a portion extending upwards on the lower blade serving as a wire cutter surface, opposite this chisel edge, the pivot bosses and the cutting surfaces being adapted so that it can be removed from the   material for re-sharpening the cutting surfaces while maintaining   the offsets between them with the first and the second   pivot boss serving as a reference surface for faci-   read the reassignment of the offset shears, and the opposite surface (88) of this wire cutter receiving the entire width of the face of this edge of the chisel, thanks to which the pinching and hooking of the wire cutting is prevented, this offset shears thus being capable of making cuts of small opposite circles up to about 51 to 64 mm in diameter. 2. Universal offset shear according to claim 1, characterized in that the upwardly extending portion of the first pivot boss is an anvil (88) and that the wire cutter is a wire cutter of the cutting pliers type with the anvil and the chisel (90) serving simultaneously as a stop   limitation for the journey of the first and second   xth cutting surface (70, 72) of the upper blades and   lower (12, 14) respectively.   3. Universal offset shear according to claim 2,   characterized in that this chisel is a beveled edge ana-   logs at a blade angle of about 40 to 60.   4. Universal offset shear according to claim 3, characterized in that this chisel has a similar beveled edge to a blade of about 50.   5. Universal offset shear according to claim 4, characterized in that the means of opposite branches (18, 20) comprise a pivot joint (26) between them and pivot joints (40, 42) with the upper blade and the lower blade respectively so that there is formed a three-point toggle mechanism between these means of opposite branches and these blades, and in that the junction angle of the pivots formed by the pivot joint (26) and each of the pivot joints (40, 42), when the blades are in the closed position, is approximately 115 to approximately, thanks to which this offset shears has greater power because the pivot joint (26) approaches neutral between pivot joints (40, 42).   6. Universal offset shear according to claim 5, characterized in that the junction angle of the pivots is about 117.   7. Universal offset shear according to claim 1, characterized in that the upwardly extending portion of the first pivot boss forms an opposite shear edge (93 ') resembling the chisel (90') for shearing between them, thanks to which the wire cutter is a wire cutter of the shear type. 8. Universal offset shears according to claim 7, characterized in that it includes associated stops (89, 91) on the means of opposite branches (18, 20) to provide a stop limiting the path of the first and the second cutting surface of the upper blades and lower respectively.   9. Universal offset shear according to claim 8,   characterized in that the chisel is a beveled edge ana-   logs at a blade angle of about 40 to 60.   10. Universal offset shear according to claim 9, characterized in that this chisel has a similar beveled edge to a blade of about 50.   11. Universal offset shear according to claim 10,   characterized in that the means of opposite branches include   carry a pivot joint (26) therebetween and pivot joints (40, 42) with the upper and lower blades (12, 14), so that there is formed a three-point toggle mechanism between the means of branches   opposite and the blades, and in that the angle formed by the arti-   pivot joint (26) and each of the pivot joints (40, 42), when the blades are in the closed position, is obtained by this offset shears because the pivot joint (26) approaches the dead center between the joints pivot (40, 42).   12. Universal offset shear according to claim 11, characterized in that the junction angle of the pivots is about 117.