CH663921A5 - GENERAL PURPOSE SHEARS. - Google Patents

Description

DESCRIPTION

The invention relates to a general-purpose shear according to the preamble of claim 1.

If sheet metal or similar material is cut with conventional hand-held sheet metal shears, then one or both edges of the cut sheet metal with the main part of the sheet metal shears can come into a disruptive position which makes it difficult to advance the sheet metal shears further, and also one Distortion or bending of the cut edges. This disturbance or impairment is greatest when irregular shapes, in particular sharp curvatures and especially small circles, are cut. As a result, conventional sheet metal shears are often supplied in mirror-image versions that are particularly adapted to a left-handed or a right-handed cut. When conventional sheet metal shears are used to cut thick, resistant, or rigid or rigid material, the material often also tends to move away from the cutting blades as they close, thereby reducing cutting performance, i.e. the efficiency is reduced. Furthermore, conventional sheet metal scissors can require long manipulations and a considerable amount of effort on the part of the user if sheet metal or flat materials are to be cut in various but frequently required designs or qualities.

As shown in U.S. Patent 2,264,840, an attempt to reduce the degradation between the cut sheet and the body of the shear is to offset the cutting edges with respect to the shank shaft portions so that the cut material passes on one side of the shaft parts. As this patent also discloses, it is practice to extend the cutting blades sideways in an approximately perpendicular direction to the work position of the shaft parts. This configuration facilitates the advancement of the sheet metal shears into the sheet metal material by reducing the extent to which the cut sheet metal has to be spread in the vertical direction in order to pass over and under the lower blade, thereby simultaneously reducing the effort of the sheet metal material pushing the cutting edges away is reduced. More recently, as shown in U.S. Patent No. 3,587,173, a hinge assembly has been proposed to reduce the force required by the user to cut thick sheet materials.

Like conventional sheet metal shears, most commercially available sheet metal shears can only be used to cut curvatures or bends in either a left or a right direction, which makes it necessary to use other mirrored sheet metal shears for cutting in the other direction To have available. Also, the transverse or sideways extending blades of available offset sheet metal shears must be handled with great care

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be sanded and aligned during manufacture, and they generally cannot be regrind cheaply or practically if they become blunt or damaged. Misuse or misuse of the blades to cut wire or other similar materials can render the metal shears unusable for cutting metal sheets.

Accordingly, there is a need for a stepped shear that can be easily and easily re-sharpened should its blades become blunt or damaged, and which includes a wire cutter of the squeeze or shear type. There is also a need for an improved handle and hinge arrangement or configuration that will make the sheet metal shears more powerful, more effective, and more suitable for use when cutting heavy or thick sheet material.

In the subject of the U.S. patent application Ser.-No. 386 049 (filed June 7, 1982 for James R. O'Keefe), a squeeze cutter is used, with part of the upper cutting leg of the scissors serving as an anvil and part of the lower cutting leg serving as a cutting or wedge piece for the wire cutter. With such an arrangement, a recess formed at the base of the cutting elements due to the manufacturing process - a kind of relief - requires that the wire to be cut is positioned in a special way, essentially in the center of the cutting tool. If, for example, a wire of small diameter is inserted at the base or at the starting point of the cutting device, the relief grinding actually precludes the wire from being cut by the anvil and the cutting piece. This relief is created as a result of the various grinding operations and passes required to grind the opposing surfaces of the cutting or wedge piece. Also, the grinding passages in the manufacture of the wedge piece according to the aforementioned US patent application generally result in a wide V-shaped wedge piece with an angle of approximately 70 ° between the side faces thereof. A wedge shaped at such an angle, although suitable for most applications, requires difficult manufacturing operations, which results in significantly higher manufacturing costs. Higher pressures and forces are also required to cut a wire because the wedge piece has a wider cutting angle, and wire of smaller and larger caliber can be easily pressed or pulled against the base (the starting point) of the cutting tool in the relief area. If this happens, it will be difficult to cut the wire and you will need to manually return the wire to the central or central position so that the wedge piece cuts or squeezes across the full wire width, with the wire at right angles between the anvil and the entire extent of the wedge piece surface is captured.

Another disadvantage of a pair of sheet metal shears according to the USA patent application mentioned is that the lower cutting leg, although offset or offset, does not offer adequate play or clearance, so that opposite circles of very small diameter cannot be cut. This shortage forces right and left hand cutting tools to be manufactured and kept in stock, since neither of the two sheet metal shears set apart can actually be regarded as a general-purpose or universal sheet metal shear that is able to perform cutting work in any direction, i.e. straight, right-hand or left-hand cuts. It should be noted here that in the most common cases, cutting arches, curves or circles down to a diameter of approximately 5 cm are sufficient for most application requirements placed on the tool.

It is therefore the object of the invention to provide an improved offset general-purpose sheet metal shears with which sheet metal or flat material can be cut both in left-hand and in right-hand curvatures and also in circles with a very small diameter, without being impeded by a Bumping or placing the cut material on the main part of the shear occurs.

It is also an object of the invention to provide an improved, offset, general-purpose, high-performance sheet metal shear in which the cutting edges can be sharpened in a practical and economical manner when they become blunt or damaged, and sharpening the wedge piece of the wire cutter in one single grinding pass can be carried out with the rotary bearing of its cutting leg.

Another object of the invention is to provide an improved, all-purpose, sheet metal shear which includes either a crimping or shearing device for cutting wire and the like. Round or rod material, so that the need for a second tool for this purpose is eliminated and misuse of the sheet material cutting edges of the offset cutting legs is reduced or eliminated.

Furthermore, the invention aims at an improved remote all-purpose sheet metal shear, which, due to a toggle joint arrangement, which provides a greater force effect at the central articulation point of a two-joint / three-pivot knee joint transmission, which is due to the general linearity of the articulation pivot points when the sheet metal shears are in their closed position is based, offers increased performance.

In addition, it is an object of the invention to provide an improved remote general-purpose sheet metal shear that has grips with a knee joint transmission of considerably greater performance, which are easier to grasp when the shear is in its open position, and which are more easily in the closed position can be pressed.

Yet another object of the invention is to provide a remote all-purpose shear that has either a squeegee or a shear cutter, with the squeegee's anvil on the upper cutting leg, the cutting or wedge piece on the lower cutting leg regardless of the type Applied type of cutting device are arranged.

It is also an object of the invention to provide a remote all-purpose shear that has a cutting or wedge piece that can be sharpened in a single grinding pass with the pivot of its cutting leg and cuts across the entire extent of the anvil in the cutting direction.

The invention is directed to improvements to hand-operated, general-purpose scissors or sheet metal shears with a wire cutter that is uninterrupted across its entire width, for cutting sheet metal or flat material and wire or other rod or bar material.

The inventive design of the sheet metal shears results from the characterizing part of patent claim 1.

The invention is explained on the basis of two exemplary embodiments in the description with reference to the drawings, further objects of the invention and the advantages to be achieved with it being clear from the description.

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The drawings show:

1 is a partially broken side view of a pair of tin snips according to the invention in its open position:

FIG. 2 shows a partially broken side view of the offset sheet metal shears from FIG. 1 in the closed or cutting position;

3 shows the section or the top view along the line 3 - 3 in FIG. 2;

FIG. 4 shows a side view of the upper cutting leg of the offset sheet metal shears shown in FIGS. 1-3;

5 shows the section or the view along the line 5 - 5 in FIG. 4;

6 shows the section or the view along the line 6 - 6 in FIG. 4;

7 is a side view of the lower cutting leg of the offset sheet metal shears shown in FIGS. 1-3;

8 shows the section or the view along the line 8-8 in FIG. 7;

9 shows the section or the view along the line 9-9 in FIG. 7;

Figure 10 is a partially broken side view of a more preferred embodiment of a stepped metal shear according to the invention in its open position.

FIG. 11 shows a partially broken side view of the offset sheet metal shears from FIG. 10 in the closed or cutting position;

12 shows the section or the top view along the line 12-12 in FIG. 11;

13 is a side view of the upper cutting leg of the sheet shear shown in FIGS. 10-12;

Fig. 14 shows the section or the view along the line

14-14 in Fig. 13;

Fig. 15 shows the section or the view along the line

15-15 in Fig. 13;

16 is a side view of the lower cutting leg of the sheet shear shown in FIGS. 10-12;

17 shows the section or the view along the line 17-17 in FIG. 16;

18 shows the section or the view along the line 18-18 in FIG. 16;

19A and 19B are broken top views or sections of opposing shear blades of typical cutting tools of the seer type, which can be used instead of crushing cutting tools if desired.

An embodiment of a stepped or angled. Sheet metal shears 10 designed according to the invention are shown in FIGS. 1-3. The sheet metal shears have an upper and a lower cutting leg 12 or 14, which can be pivoted about a main pivot pin 16 by an upper and a lower handle 18 or 20.

Movement of the cutting legs 12 and 14 between the open position shown in FIG. 1 and the closed position. 2 shows a cutting of a sheet metal piece 22 or wire piece 24 located between the cutting legs 12, 14 (see FIG. 1).

The handles 18:20 can be pivoted about a handle pivot pin 26 which lies between the front ends of the handles 18, 20. The rear handles 28 and 30 of the respective handles 18, 20 are covered with an upper and a lower handle 32 and 34 respectively. The booklets 32, 34 are preferably formed by immersion or compression molding, in such a way that they each receive outwardly protruding protrusions 36 and 38 in order to prevent the user's hand from sliding forward when the sheet metal shears 10 are used.

The preferred material for booklets 32, 34 is a hot-dip plastisol which is commercially available from Sinclair Rush, St. Louis, Missouri / USA.

The handles 18, 20 extend further from the handle pivot pin 26 and away from one another, so that they are pivotally connected to the cutting legs 12, 14 on pivot pins 40 and 42. In the open position (FIG. 1), an acute angle is preferably formed between an imaginary line connecting the pins 26 and 40 and an imaginary line connecting the pins 26 and 42. In a preferred manner, the handles 18, .20 have a U-shape in cross section, as shown in FIG. 3, wherein side parts 44 and 46 which are spaced apart in the transverse direction are connected by a web 48. A spring 50 designed in the manner of the letter Omega, which is held in place by the handle pivot pin 26, lies with its ends against the webs 48 of the handles 18, 20, so that the sheet metal shears 10 are pressed into their open position. Other elements or devices that produce a similar effect can also be used. A sleeve 51 is arranged between the handle pivot pin 26 and the omega spring 50, which centers this spring 50 and keeps it at a distance from the handle pivot pin 26. Although this sleeve 51 is not an essential part for working the sheet metal shears 10, it has been shown that it extends the life of the omega spring 50.

In the open position, the upper cutting leg 12 runs upwards and backwards from the main pivot pin 16 to its pivotable attachment to the pivot pin 40, as shown in FIG. 1. The lower cutting leg 14 extends from the main pivot pin 16 backwards to its pivotable attachment to the pivot pin 42. In response to a closing movement of the handles 18 and 20, the pivot pins 40, 42 perform a rotary movement around the handle pivot pin 26, with the rear parts 54 and 56 of the cutting legs 12 and 14 are spread. As shown in FIG. 3, these rear parts 54, 56 have a sufficient thickness so that they are snugly received by the side parts 44, 46 of the handles 18, 20 in order to align the upper and lower cutting legs 12 and 14 maintain. An adjustment or readjustment of the play between the side parts 44 and 46 and the rear parts 54 and 56 is provided by adjusting nuts 58 on the pivot pins 40 and 42.

The main pivot pin 16 is screwed into a bore 60 of the shaft part 62 of the upper cutting leg 12 and produces a sliding fit with a hole 64 in the shaft part 66 of the lower cutting leg 14. A lock nut 68 is tensioned against the shaft part 62 in order to maintain the set length of the main pivot pin 16.

Cutting edges 70 and 72 of the cutting legs 12 and 14 are located within a plane parallel to the adjacent shank parts 62 and 66 of the respective cutting legs, but offset laterally from the shank parts, as shown in FIG. 3. It should be pointed out here that the offset or offset is sufficient to allow a part separated from the sheet metal piece 22 to pass the side of the shaft part 66.

It has been found that the cutting of a piece of sheet metal 22 is favored if the cutting edges 70 and 72 have a curved profile in the side view, as shown in FIGS. 4 and 7. In the shown and preferred embodiment, the upper cutting edge 70 is determined by a radius of 20.32 cm, which is also determining for the lower cutting edge 72. However, the design shown serves more illustrative purposes and other arch designs with a similar effect can be used. As clearly shown in FIGS. 4-8

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men, the front parts 84 and 86 of the two cutting legs 12, 14 each extend to the side almost at right angles with respect to the shaft parts 62 and 66. This configuration facilitates the cutting of a flat surface, eg. B. a table, placed piece of sheet metal 22 and also reduces the amount by which the cut surfaces of the workpiece must be spread in order to pass above and below the lower cutting leg 14.

The cutting legs 12 and 14 are preferably ground hollow on their respective surfaces 78 and 80 in order to ensure that the upper and lower cutting edges 70, 72 have a uniform width in the side view, thereby at the same time providing for regrinding of the cutting legs, what will be discussed later. The rear portion of the lower cutting edge 72 is provided with a recess or a relief 82 to facilitate the grinding of the cutting edge 72 and to ensure a smooth sliding of the cutting edges 70, 72 during the cutting process. The front parts 84 and 86 of the cutting legs 12, 14 are, as shown in FIGS. 6 and 9, curved inwards so that convex surfaces are formed. This configuration of the front parts 84, 86 ensures sufficient strength and firmness of the cutting edges 70 and 72, while at the same time enabling and promoting the handling and mobility of the sheet metal shears 10 when cutting when space is limited.

The wire piece 24 is cut by abutment of an anvil 88 formed on the upper cutting leg 12 against a cutting or wedge piece 90 configured on the lower cutting leg 14. The anvil 88 and wedge piece 90 are arranged in such a way that the rotation of the Cutting leg is terminated when the sheet metal shears 10 are in their closed position shown in FIG. 2. The wedge piece 90 serves as a cutting edge, around a wire, smaller rod and round rod material or the like, which is placed on the anvil 88, when the sheet metal shears 10 move from their open (see FIG. 1) to their closed position (see Fig. 2) to cut. It is clear that other opposing cutting surfaces, such as. B. of oblique, diagonal or miter cutting tools, can be used with the same effect at the location of the anvil 88 and the wedge piece 90.

It is an essential feature of the invention that the cutting edges 70 and 72 can be reground in order to repair them if they are worn or damaged. It can be seen from FIG. 3 that grinding and thus material removal at either the upper or the lower cutting edge 70 or 72 will normally lead to a transverse clearance between these cutting edges, whereby a shearing or cutting operation of the sheet metal piece 22 is excluded. The displacement of the cutting edge 70 with respect to the shaft part 62 is reduced by such grinding, while the displacement of the cutting edge 72 with respect to the shaft part 66 is increased by the grinding. For this reason, the commercially available sheet metal shears cannot be reground in an expedient and practical manner if they have become blunt or damaged.

Regrinding of the sheet metal shears 10 according to the invention is facilitated and promoted by protruding surfaces 92 and 94, which can be referred to as rotary bearings or hub parts and are formed on the adjacent surfaces of the shaft parts 62 and 66. The pivot bearings 92.94 are flat projections or projections,

which protrude beyond the surfaces of the shaft parts 62, 66 which are perpendicular to the main pivot pin 16. The pivot bearing 92 need not have any special design, but it can be provided with a semicircular front part 96 concentric with the main pivot pin 16 and a rectangular rear part 98, as shown in FIG. 4. Similarly, the pivot bearing 94 may include a semi-circular front portion 100 concentric with the main pivot pin 16 and a triangular rear portion 102 as shown in FIG. 7. The pivot bearings 92 and 94 represent improved bearing surfaces between the cutting legs 12 and 14, while at the same time maintaining the alignment or the guidance of the cutting edges 70 and 72 to one another. The backs 98 and 102 work together to prevent the cutting edges 70 and 72 from spreading during the cutting operation.

In the sheet metal shears 10, the offset or offset of the cutting edges 70, 72 is determined by the location of the pivot bearings 92 and 94. The consequence of this is that the sheet metal shears can be reground by grinding both the cutting edges 70, 72 and the respective pivot bearings 92, 94. It should be obvious that no change in the displacement of the upper cutting edge 70 will occur if the same material thicknesses are removed from the upper cutting edge 70 and the rotary bearing 92. Similarly, no change in the offset of the lower cutting edge 72 will occur if the same material thicknesses are ground off the lower cutting edge 72 and the pivot bearing 94. Thus, one of the cutting legs 12, 14 can be reground and sharpened as necessary, or both cutting legs can be ground without causing a transverse clearance or a gap between the cutting edges 70 and 72.

The resharpening of the respective cutting legs is further simplified in that it is not necessary to grind on curved surfaces. The upper and lower cutting edges 70, 72 are ground in a plane that is substantially parallel to the respective pivot bearings 92 and 94. Here, these rotary bearings 92, 94 can first be machined to create reference surfaces for grinding the cutting edges 70 and 72. The hollow ground surfaces 78 and 80 of the cutting legs 12, 14 eliminate the need for grinding any other surfaces or edges during regrinding. It has been found that there is sufficient and satisfactory regrinding ability or possibility if the height of the pivot bearings 92, 94 with respect to the adjacent shaft parts 62 and 66 is 0.8 mm. The articulated connection of the cutting legs 12, 14 with respect to the handles 18 and 20 allows the cutting edges 70, 72 to be clamped in place in a grinding device while leaving the pivot and pivot pins 26, 40 and 42 in place, since only the main pivot pin 16 must be removed.

It has also been found that the cutting of the sheet metal piece 22 is favored if the upper and lower cutting edges 70, 72 do not run exactly parallel with respect to the pivot bearings 92, 94, but instead have a slight angular course in order to prevent the cutting legs from closing as they progress Interacting or meeting to accomplish and enforce. Although different values can be used for such interlocking with similar effects, it has been found that an angle of approximately 15 'on each of the cutting edges 70, 72 is preferred in order to achieve a total interlocking of approximately 0.5 °. This gripping or clamping the blades or cutting legs during the late

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The other part of the cutting process is pressed tightly together to ensure a cutting action or effect. The desired angle and the desired offset can be formed in a suitable and economical manner if the cutting legs 12, 14 are first ground or later re-sharpened for re-sharpening.

It should be understood that the grinding of the pivot bearings 92 and 94 merely to explain the concept according to the invention for removing material from the adjacent shaft parts of the upper and lower cutting legs 12 and 14 in order to enable the cutting edges 70, 72 to be resharpened. serves.

Milling or other machining operations can also be used instead of grinding, provided that such machining is not precluded by the hardness of the cutting legs 12 and 14.

Another feature can be seen in the locking device, which can be engaged by hand in order to prevent the sheet metal shears 10 from opening from the closed position shown in FIG. 2. The pivot 40 is provided with a shoulder between its shaft and head part. A locking tab 104 is held on the pivot 42 outside the side part 46 of the lower handle 20 and outside the corresponding side part of the upper handle 18, the free end of which is notched from one side, so that a hook part 106 is formed. The locking tab 104 can be moved by hand between the pivot pin 40 and the handle pivot pin 26 from a first position, shown in FIG. 1, in which working with the sheet metal shears 10 is possible, into a second position, shown in FIG. 2, in which the sheet metal shears 10 are locked in their closed position. In this second position, the hook part 106 at the free end of the locking plate 104 is pivoted for engagement with the shoulder on the pivot pin 40, the locking plate 104 being subjected to pressure by the omega spring 50, so that it is held locked. The latch tab 104 can be conveniently released or locked by a thumb of the user, which enables one-handed work.

Another feature to be emphasized of the sheet metal shears 10 lies in a triangular incision or recess 110 which lies in line or in alignment with the path of the cut sheet metal piece 22 which passes over the front part 86 of the lower cutting leg 14 in the shaft part 66 of the lower cutting leg 14. With this recess 110, the sheet metal shears 10 can be used to make cuts that rotate to the right and to the left. It should be clear that the configuration of the sheet metal shears 10, which is shown as the preferred embodiment, is particularly suitable for straight and left-handed cuts. It was found, however, that 110 right-hand cuts with a diameter of 10 cm or more can be carried out by the puncture, so that the need for own sheet metal shears, which are particularly adapted to right-hand cuts, is eliminated. Similar sheet metal shears, which have a mirror-image configuration, which are particularly suitable for straight and right-handed cuts and can also perform left-handed cuts with a diameter of 10 cm or more, can of course be provided.

Another important feature of the shears 10 can be seen in the fact that the handles 18 and 20 are particularly suitable and designed to apply a force over the entire range of motion of the cutting legs 12, 14. In contrast to conventional offset sheet metal shears, the handle pivot pin 26 is arranged relatively close to the upper and lower handles 32, 34. That has to

The result is that the angle formed between the booklets 32 and 34 in the open position of the sheet metal shears 10 (see FIG. 1) can be larger than in the case of conventional sheet metal shears. In the open position, the forward portions of booklets 32, 34 are spaced apart to allow the handles 18 and 20 to be gripped or spanned by the user's hand near the bumps 36 and 38 for maximum leverage .

The lower handle 20 is designed in such a way that the position of the lower booklet 34 in the open position of the sheet metal shears does not cause any impairment or interference with respect to a workbench on which the sheet metal piece 22 lies for cutting. As the upper and lower cutting legs 12 and 14 are moved to the closed position shown in FIG. 2, the rear portions of the upper and lower booklets 32 and 34 are continuously held at an ideal distance for maximum leverage. In addition, the cutting legs 12 and 14 and the handles 18 and 20 constitute a four-part link mechanism which causes an increase in the transfer of the force applied by hand to the cutting edges 70 and 72 in order to reduce the effort and hassle as well as signs of fatigue on the part of the user.

A variety of materials can be used to manufacture the cutting legs and the handles, but this depends on the sheet material to be cut. In the embodiment shown and preferred, the cutting legs are forged from alloyed tool steels and ground or machined to the shape shown. Such a structural design offers sufficient strength to be able to cut sheet steel with the tin snips. However, other materials and less complex or expensive shaping processes can also be used, in particular if less solid or hard sheet metal material has to be cut. The handles 18 and 20 can be formed in an advantageous and economical manner from unalloyed steel by means of various pressing processes. The latch plate 104 can also be manufactured cheaply and economically from a steel sheet.

With reference to FIGS. 10-19, an improved general-purpose sheet metal shear 10 'of a stepped or angled type with an improved wire cutter is described. The sheet metal shears 10 'have an upper and a lower cutting leg 12' or 14 ', which can be pivoted about a main pivot pin 16' by an upper and a lower handle 18 'or 20'. Movement of the cutting legs 12 'and 14' between the open position shown in FIG. 10 and the closed position shown in FIG. 11 causes a piece of sheet metal 22 'or wire piece 24' located between the cutting legs 12 ', 14' to be cut. see Fig. 10).

The handles 18 ', 20' can be pivoted about a handle pivot pin 26 'which lies between the ends of the handles 18', 20 '. The rear handles 28 'and 30' of the respective handles 18 ', 20' are covered with an upper and lower handle 32 'and 34'. The booklets 32 ', 34' are preferably formed by immersion or compression molding in such a way that they each receive outwardly protruding bumps 36 'and 38' in order to prevent the user's hand from sliding forward when the sheet metal shears 10 'are used.

The handles 18 ', 20' extend further forward and away from the handle pivot pin 26 'so that they can be pivotally connected to the cutting legs 12', 14 'on pivot pins 40' and 42 '. In the open position (FIG. 10), an imaginary line connecting the pins 26 'and 40' and an imaginary line connecting the pins 26 'and 42' are preferably used

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formed an acute angle. This acute angle is in the range of approximately 70 "in both embodiments. In the closed position, this angle between the two imaginary lines of the same length is preferably increased by approximately 10 to 15 (to 114: to 119"), which is a considerably more efficient detection due to the flatter knee joint transmission and the general linearity of the articulation pivot points, the result is that the offset sheet metal shears are in a closed position. If the pivot pins 40 ', 42' are closer to the handle pivot pin 26 ', the latter is closer to the dead center, at which the force for the joint mechanism is at its maximum. Thus, in this embodiment according to the invention, the distance between the handle pivot pin 26 'and the pivot pin 40', 42 'is about 6 mm smaller, which compared to a sheet metal shear of the embodiment shown in Figs. 1-8 to an improved offset Tin snips with considerably greater force. Here, in the closed position, the two opposite, equal angles of the triangular “over-center” joint mechanism with the further imaginary line connecting the pivot pins 40 'and 42' form angles of the order of about 30 to 35 degrees.

In a preferred manner, the handles 18 ', 20' have a U-shape in cross section, as shown in FIG. 12, wherein side parts 44 'and 46' which are spaced apart in the transverse direction are connected by a web 48 '. A spring 50 'designed in the manner of the letter Omega, which is held in place by the handle pivot pin 26', lies with its ends against the webs 48 'of the handles 18', 20 ', so that the sheet metal shears 10' in its open position is pressed. Other elements or devices for applying pressure can also be used in this embodiment. Although the centering sleeve 51 'is not essential for the operation of the sheet metal shears 10', it does considerably extend the life of the omega spring 50 '.

In the open position, the upper cutting leg 12 'extends upwards and backwards from the main pivot pin 16' to its pivotable attachment to the pivot 40 ', as shown in FIG. 10. The lower cutting leg 14 'runs from the main pivot pin 16' backwards to its pivotable attachment to the pivot 42 '. In response to a closing movement of the handles 18 'and 20', the pivot pins 40 ', 42' perform a rotary movement about the handle pivot pin 26 ', the rear parts 54' and 56 'of the cutting legs 12' and 14 'being spread apart . As shown in FIG. 12, these rear portions 54 ', 56' are of sufficient thickness to be snugly received by the side portions 44 ', 46' of the handles 18 ', 20' to align the upper and lower cutting legs 12 'and 14'. An adjustment or readjustment of the play between the side parts 44 'and 46' and the rear parts 54 'and 56' is provided by adjusting nuts 58 'on the pivot pins 40' and 42 '.

The main pivot pin 16 'is screwed into a bore 60' of the shaft part 62 'of the upper cutting leg 12' and creates a sliding fit with a hole 64 'in the shaft part 66' of the lower cutting leg 14 '. A lock nut 68 'is tensioned against the shaft part 62' in order to maintain the set length of the main pivot pin 16 '. Cutting edges 70 'and 72' of the cutting legs 12 'and 14' are located within a plane parallel to the adjacent shank parts 62 'and 66' of the respective cutting legs, but offset laterally from the shank parts, as shown in FIG. 13. It should be pointed out here that the offset or offset is selected to be sufficient to give a part cut off from the sheet metal piece 22 'the possibility of easily passing the side of the shaft part 66' and, what is more important, the improved tool in FIG move the stand to be able to cut a counter circle with a smallest diameter of about 5 cm. This arrangement enables a user to cut sheet metal for most work with a single tool, since the very widely spaced blades allow not only straight cuts but also sharp or strong curvatures in a left or right direction.

Furthermore, in this embodiment according to the invention, the cutting edges 70 'and 72' are curved in the same way when viewed from the side with the same radii, as shown in FIGS. 13 and 16, so that convex cutting edges or surfaces are presented to the workpiece. The front parts 84 ', 86' of the respective cutting legs 12 'and 14' extend laterally almost at right angles to the shaft parts 62 'and 66', as is also the case in the embodiment of FIGS. 1-9.

Preferably, the cutting legs 12 'and 14' are hollow ground on their respective surfaces 78 'and 80' to ensure that the upper and lower cutting edges 70 ', 72' have a uniform width in the side view, thereby simultaneously providing for Regrinding the cutting leg is hit, which will be discussed. The rear portion of the lower cutting edge 72 'is provided with a recess or a relief 82' to facilitate the grinding of the cutting edge 72 'and to ensure a smooth sliding of the cutting edges 70', 72 'during the cutting process. The front parts 84 'and 86' of the cutting legs 12 ', 14' are, as shown in FIGS. 15 and 18, curved inwards so that convex surfaces are formed. This configuration of the front parts 84 ', 86' ensures sufficient strength and strength of the cutting edges 70 'and 72', while at the same time enabling and promoting the handling and mobility of the sheet metal shears 10 'when cutting when space is limited.

The wire piece 24 'is cut by abutment of an anvil 88' formed on the lower cutting leg 14 'with a cutting or wedge piece 90' designed on the upper cutting leg 12 '. The arrangement of the anvil 88 'and the wedge piece 90' is such that their abutment stops the rotation of the cutting legs when the metal shears 10 'are in their closed position, shown in FIG. 11. The wedge piece 90 'serves as a cutting edge around a wire, smaller bar and round bar material or the like, which is placed on the anvil 88', when the sheet metal shears 10 'move from their open position (see FIG. 10) to blow their closed position (see Fig. 11). It is clear that the opposing cutting surfaces cut a wire through a crimp cutting operation that is different from other cutting operations, e.g. B. a shearing process, is preferable because a special path limitation is not necessary, cut. In the case of shear cutting edges, the cutting edges between the opposing cutting legs being designed in a conventional scissor shape, a pair of end stops 89 and 91, as indicated by dashed lines in FIGS. 10 and 11, must be present between the grip legs in order to pivot the movement limit the cutting leg. End stops of this type are required for each of the embodiments shown in FIGS. 19A and 19B, where the wire crimping cutters have been replaced by wire shear cutters. 19A, anvil 88 'is simply ground to clear the way of the cutting or wedge piece 90' and by moving the cutting piece 90 'on the opposite one

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Cutting edge 93 'over, as shown in dashed lines. cut the wire 24 '. 19B, the opposite cutting edge 93 'is offset outwards, since the sharp cutting edge of the cutting or wedge piece 90' is arranged at an angle which is opposite to that of the wedge piece 90 'of FIG. 19A.

Both with a squeeze cutter and with a shear cutter, no relief is required at the base or the starting point of the cutting elements, since the cutting or wedge edges are all formed by grinding across the full surface of the cutting elements. In the improved sheet metal shears according to the invention, only a single grinding step needs to be carried out in order to produce each of the two types of cutting edge, since the cutting edges, starting from a straight edge, are formed by grinding an oblique or angled edge. Thus, the knife or shear edge designed in this way can be made much smaller in the size of its angle and consequently made considerably sharper than a conventional relatively blunt squeezer with a V-shape. 1-9, this has an angle of, for example, approximately 70, while in the preferred embodiment in question an angle of approximately 40c to 60 shows satisfactory results. It is believed that during cutting with the acute-angled cutting tool according to the invention, considerably less friction is generated compared to the previous crimping cutter. In these cases, the cutting elements were already made of stronger steels in order to maintain sharp cutting edges. It has been shown that an angle of approximately 50c is suitable and preferred for putting the invention into practice. It should also be clear that with an obtuse angle of 70: for the V-shaped crimping cutter according to FIGS. 1-9, greater forces are required to cut a wire by crimping, since it can be assumed that the wider wedge-shaped cutting piece cutting has a considerably higher frictional resistance.

It should also be clearly recognizable that with a cutting element having a full area over its width, even very thin wires can be cut through easily and correctly, since there is no undercut or a free area at the base of any of the cutting elements. Thus, the thin wire can be placed anywhere along the cutting edge or the anvil - whether it is a squeeze or shear cutter - without fear that the thin wire will be undercut at the base of the cutting element or anvil and is either not or incompletely severed. In such cases, the wire had to be repositioned exactly in the middle of the cutting edge in order to cut the wire again at another point or to finish the incomplete cut at the same point or again as close as possible to the first attempt, as close as it was without it the use of special tools for precise alignment of the cutting tool for a second cut on the wire is conceivable. to cut.

It is an essential feature of the invention that the cutting edges 70 'and 72' can be reground in order to repair them if they are worn or damaged. It can be seen from FIG. 12 that grinding and thus material removal at either the upper or the lower cutting edge 70 'or 72' will normally lead to a transverse clearance between these cutting edges, as a result of which a shearing or cutting operation of the sheet metal piece 22 ' is excluded. The displacement of the cutting edge 70 'with respect to the shaft part 62' is reduced by such grinding, while the displacement of the cutting edge 72 'with respect to the shaft part 66' is increased by the grinding. For this reason, as has already been stated above, the commercially available sheet metal shears cannot be reground in an expedient and practical manner if they have become blunt or damaged.

Regrinding of the sheet metal shears 10 'according to the invention is facilitated and promoted by protruding surfaces 92' and 94 ', which are referred to as rotary bearings and are formed on the adjacent surfaces of the shaft parts 62' and 66 '. The pivot bearings 92 ', 94' are planar projections or projections which protrude beyond the surfaces of the shaft parts 62 ', 66' which are perpendicular to the main pivot pin 16 '. In the preferred embodiment, the pivot bearing 92 'has a special configuration in that it comprises a part 96' which is generally concentric with the main pivot pin 16 'and a narrow, generally rectangular and upwardly directed part 97, as shown in FIG. 13. The pivot bearing 94 'is provided with a generally circular portion 100' concentric with the main pivot pin 16 'and a generally upward portion 101' as shown in FIG. The pivot bearings 92 'and 94' represent improved bearing surfaces between the cutting legs 12 'and 14', while at the same time maintaining the alignment or guidance of the cutting edges 70 'and 72' to each other. The upwardly extending parts 97 and 101 'each increase the strength of the anvil 88' and also of the cutting piece 90 'itself.

In the sheet metal shears 10 ', the offset or offset of the cutting edges 70', 72 'is determined by the location of the pivot bearings 92' and 94 '. The consequence of this is that the sheet metal shears 10 'can be reground by grinding both the cutting edges 70', 72 'and the respective rotary bearings 92', 94 'and also their upward-facing parts 97 and 101'. It is obvious that no change in the offset of the upper cutting edge 70 'will occur if the same material thicknesses are removed from the upper cutting edge 70' and the pivot bearing 92 '. Similarly, there will be no change in the offset of the lower cutting edge 72 'if the same material thicknesses are ground off the lower cutting edge 72' and the pivot bearing 94 '. Thus, one of the cutting legs 12 ', 14' can be reground and sharpened as required from time to time during normal use, or both cutting legs can be ground without any transverse clearance or a gap between the cutting edges 70 '. and 72 '.

The resharpening of the respective cutting legs is further simplified in that it is not necessary to grind on curved surfaces. The upper and lower cutting edges 70 ', 72' are ground in a plane which is substantially parallel to the respective pivot bearings 92 'and 94'. Here, these rotary bearings 92 ', 94' can first be machined to create reference surfaces for grinding the cutting edges 70 'and 72'. The hollow ground surfaces 78 'and 80' of the cutting legs 12 ', 14' eliminate the need for grinding any other surfaces or edges during regrinding. It has been found that there is sufficient and satisfactory regrinding ability or possibility if the height of the pivot bearings 92 ', 94' with respect to the adjacent shaft parts 62 'and 66' is 0.8 mm. The articulation of the cutting legs 12 ', 14' with respect to the handles 18 'and 20' allows the cutting edges 70 ', 72' to be held in a grinding device while leaving the swivel

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and pivot 26 ', 40' and 42 'in place since only the main pivot 18' needs to be removed.

As stated above, the cutting of the sheet metal piece 22 'is favored if the upper and lower cutting edges 70', 72 'are not exactly parallel with respect to the pivot bearings 92', 94 ', but instead have a slight angular course in order to Close the cutting legs to progressively engage or meet and enforce. Although different values can be used for such interlocking with similar effects, it has been found that an angle of approximately 15 'on each of the cutting edges 70', 72 'is preferred in order to achieve a total interlocking of approximately 0.5 ° . By this gripping or clamping, the blades or cutting legs are pressed tightly together during the later part of the cutting process in order to ensure a cutting activity or action. The desired angle and the desired offset can be formed if the cutting legs 12 'and 14' are initially ground or later re-ground for re-sharpening.

A suitable locking device which can be locked by hand in order to prevent an opening movement of the sheet metal shears 10 'from its position shown in FIG. 11 is shown in FIGS. 10 and 11. The pivot 40 'is provided with a shoulder between its shaft and head part. A locking tab 104 'is held on the pivot 42' outside the side part 46 'of the lower handle 20', the free end of which is notched from one side, so that a hook part 106 'is formed. The locking tab 104 'is manually moved between the pivot pin 40' and the handle pivot pin 26 'from a first position, shown in FIG. 10, in which working with the sheet metal shears 10' is possible, into a second one, in FIG. 11 Position shown movable, in which the sheet metal shears 10 'is locked in its closed position. In this second position, the hook part 106 'at the free end of the locking plate 104' is pivoted for engagement with the shoulder on the pivot 40 ', the locking plate 40' being subjected to pressure by the omega spring 50 'so that it is held locked. The locking tab 104 'can be conveniently released or locked by a thumb of the user, which enables one-handed work.

Although the cutting edges 70 'and 72' of the cutting legs 12 ', 14' are considerably offset sideways from the pivot bearings, they provide a separate, general-purpose sheet metal shear which is capable of closing small counter circles with a diameter of approximately 5 cm In addition, a triangular incision or puncture 110 'can be provided in the shaft part 66' of the lower cutting leg 14 'in line or in alignment with the path of the cut sheet metal piece 22' which passes over the front part 86 'of the lower cutting leg 14' . By means of this recess 110 ', the sheet metal shears 10' can be used to make cuts which rotate to the right and to the left. It should be clear that both of the designs of sheet metal shears discussed here are particularly suitable for straight and left-handed cuts, but that the improved embodiment shown in FIGS. 10-19 can also perform right-handed cuts in the same way, and in cases in which a small circle or sharp curvature occurs opposite to the normal orientation of the tool. Thus, the embodiment according to FIGS. 10-19 allows right-hand cuts with a diameter of approximately 5 cm. As a result, the need for your own metal shears, which are particularly adapted to right-hand cuts, is eliminated for almost all practical purposes.

Another important feature of the sheet metal shears 10 'is that the handles 18' and 20 'are particularly suitable and designed to apply a force over the entire range of motion of the cutting legs 12', 14 '. In contrast to conventional offset sheet metal shears, the handle pivot pin 26 'is arranged close to the upper and lower handle 32', 34 ', namely it is about 6 mm closer to the pivot pin 40' compared to the embodiment of FIGS. 1-9. and 42 '. The result of this is that the angle formed between the booklets 32 'and 34' in the open position of the sheet metal shears 10 '(see FIG. 10) is larger than in the case of conventional sheet metal shears and is also larger than that in accordance with FIG. 1 -9. Due to the arrangement of the pivot pins 40 ', 42' closer to the handle pivot pin 26 ', the angle between the “imaginary joint rods” between the pivot pin 26' and each of the pivot pins 40 'and 42' is preferably in a size range of approximately 115 ° to about 120 °; this angle is preferably 117 ° in the closed position of the metal shears. Such a construction creates a more powerful metal shear in that the center of the three-part linkage approaches the dead center, in which the three pivot points would form a straight line that means maximum force.

In the open position, the front portions of booklets 32 ', 34' are spaced apart to allow handles 18 'and 20' to be gripped or spanned by the user's hand near bumps 36 'and 38' to to get maximum leverage. The lower handle 20 'is designed in such a way that the position of the lower booklet 34' in the open position of the sheet metal shears does not cause any impairment or interference with respect to a workbench on which the sheet metal piece 22 'lies for cutting. As the upper and lower cutting legs 12 'and 14' are moved to the closed position shown in Fig. 11, the further rear portions of the upper and lower booklets 32 'and 34' are continuously held at an ideal distance for maximum leverage.

It will be appreciated that various changes and modifications to the preferred embodiments will be apparent to those skilled in the art. For example, Rivets or other swivel elements can be used in the place of the four bolts or pegs without affecting the operation of the metal shears.

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Claims (8)

663 921 1. All-purpose sheet metal shears of the offset type for cutting wire and sheet metal material, with an upper and lower cutting leg, each having a first and second pivot bearing and a first and second cutting edge offset with respect to the plane of the first and second pivot bearing, and with a rotating element which pivotally connects the upper and lower cutting legs for rotation by means of mutually opposed handles about an axis perpendicular to the first and second rotary bearings, the handles pivoting the upper and lower cutting legs about the rotating element in such a way that the first and second cutting edges between an open and a closed position for cutting sheet metal material located between them, characterized by an upwardly extending part of the one rotary bearing (92, 92 ') forming a beveled cutting piece (90, 90') of a wire cutter, the one cutting edge (70, 70 ') is designed for simultaneous material removal on it with the sharpening of the cutting piece (90, 90 '), by an upwardly extending part on the lower cutting leg (14, 14'), which serves as a wire cutting surface opposite the cutting piece (90, 90 ') , by designing the two rotary bearings (92, 94, 92 ', 94') and the two cutting edges (70, 72, 70 ', 72') for material removal from these for re-sharpening the cutting edges while maintaining their displacement, the first and second rotary bearings (92, 94, 92 ', 94') serve as a reference surface to facilitate the re-sharpening of the offset sheet metal shears (10, 10 '), and through one extending along the entire surface of the cutting piece (90, 90') uninterrupted formation of the opposite rotary cutter surface, which prevents pinching and incomplete cutting of the wire during cutting. 2. Tin snips according to claim 1, characterized in that the upwardly extending part of the one rotary bearing (92) is an anvil (88) and that the wire cutter is of the squeeze type, the anvil (88, 88 ') and that Wedge-shaped cutting piece (90, 90 ') simultaneously serve as an end stop for the stroke of the first and second cutting edge (70, 72, 70', 72 ') on the upper and lower cutting legs (12, 14, 12', 14 '). 2nd PATENT CLAIMS 3. Sheet metal shears according to claim 1, characterized in that the cutting edge of the wedge-shaped cutting piece (90, 90 ') lies in an angular range from 40 ° to 60 °. 4. Sheet metal shears according to claim 3, characterized in that the angle of the cutting edge of the cutting piece (90, 90 ') is approximately 50 °. 5. Sheet metal shears according to one of claims 1 to 4, characterized in that the mutually opposite handles (18, 20, 18 ', 20') arranged between them handle pivot pin (26, 26 ') and rotary connections (40, 42, 40 ', 42') with the upper and lower cutting legs (12, 14, 12 ', 14') so that there is a three-point knee joint transmission between the opposing handles and the cutting legs, and that between the handle pivot pin (26 , 26 ') and each of the rotary connections (40, 42, 40', 42 ') in the closed state of the cutting legs formed joint angle in the range of 115 ° to 120 °, so that due to the approach of the pivot pin to the remote sheet metal shears Dead center between the slewing rings greater performance is achievable. 6. tin snips according to claim 5, characterized in that the joint angle is about 117 °. 7. Sheet metal shears according to claim 1, characterized in that the upwardly extending part of the one rotary bearing forms a shear edge (93 ') opposite the wedge-shaped cutting piece (90'), on which the cutting edge of the cutting piece (90 ') of the Design trained wire cutter glides past. 8. Sheet metal shears according to claim 7, characterized by mutually adapted end stops (89, 91) on the mutually opposite handles (18 ', 20'), the stroke of the first and second cutting edge (70 ', 72') on the first and second cutting legs (12 ', 14') limit.