US3686991A

US3686991A - Apparatus for cutting a sheet material

Info

Publication number: US3686991A
Application number: US8924A
Authority: US
Inventors: Sakae Fujimoto
Original assignee: Ricoh Co Ltd
Current assignee: Ricoh Co Ltd
Priority date: 1969-02-20
Filing date: 1970-02-05
Publication date: 1972-08-29
Anticipated expiration: 1989-08-29
Also published as: CA927273A; FR2032900A5; GB1290619A; JPS5035706B1; DE2007689A1; DE2007689B2

Abstract

An apparatus for cutting a sheet material comprising a barshaped cutter receiving member disposed to extend across the width of the sheet material in contact with one surface thereof and an annular cutter whose center axis is nearly normal to an edge of the cutter receiving member. The sheet material can be cut by the annular cutter as the latter is rolled with a portion of its peripheral edge maintained in pressing engagement with the edge of the cutter receiving member.

Description

United States Patent Fujimoto 1 51 Aug. 29, 1972 [54] APPARATUS FOR CUTTING A SHEET MATERIAL [72] Inventor: Salraehflimoto, Tokyo, Japan [73] Assignee: Kabushiki-Kaisha Rlcoh,

Japan [22] Filed: Feb. 5, 1970 [2]] Appl. No; 8,924

Tokyo,

301 Foreign Application Priority om Feb. 20, 1969 Japan ......................44/l3085 52 us. c1. ..s3/4s2, 83/487, 83/564, 83/582, 83/614 51 Int. (:1. ..B26d 1/20 [58] Field of Search ..83/485489, 614, 83/353, 564, 482

[56] References Cited UNITED STATES PATENTS 3,282,140 11/1966 Sasabuchietal.... ....3/353X 3,221,585 12/1965 Staar 83/614 X FOREIGN PATENTS 0R APPLICATIONS 180,251 1/1907 Germany ..83/487 719,649 4/1942 Germany ..83/485 Primary Examiner-Andrew R. Juhasz Attorney-McGlew and Toren [57] ABSTRACT Anapparatus for cutting a sheet material comprising a bar-shaped cutter receiving member dispoaed to extend across the width of the sheet material in contact with one surface thereof and an annular cutter whose center axis is nearly normal to an edge of the cutter receiving member. The sheet material can be cut by the annular cutter as the latter is rolled with a portion of its peripheral edge maintained in pressing engagement with the edge of the cutter receiving member.

BClaImglZDrawlngFigures PAIENTEII B 2 3.686.991

sum

1 or 4 IN VENTOR SFIKHE 'FUJIMOTO BY 1 ya mm.

ATT( 7RNE Y PATENTED I972 3.686.991

saw a or 4 INVENTOR snxne Fujmoro ATW )RNI' Y PATENTEB MIC 29 0912 SHEU 3 BF 4 INVENTOR SHKHE 'FUJIMOTO BY 'fw K lam.

Tn IINEY APPARATUS FOR CU'I'IING A SHEET MATERIAL BACKGROUND OF THE INVENTION In copiers and other machines which use a roll of photosensitive sheet material or a roll of recording sheet material, there is generally provided an apparatus for cutting such sheet material after it is paid out from the roll.

One apparatus for cutting a sheet material used with a copier known in the art comprises a fixed cutter 2 disposed over one surface of the photosensitive sheet material I paid out from the roll and arranged to extend along the width thereof, and a movable cutter 3 disposed below the other surface of the photosensitive sheet material I to cooperate with the fixed cutter 2 as shown in FIG. 1. The photosensitive sheet material is cut by a cutting edge of the fixed cutter and a cutting edge 30 of the movable cutter as the movable cutter 3 is rotated in the direction of the arrow A. A

The prior art apparatus for cutting a sheet material referred to hereinabove has disadvantages. The operation of replacing the cutters, particularly the movable cutter, with new cutters is troublesome and time consuming when the cutting edges of old cutters are worn. The movable cutter is high in cost. The resistance of the sheet material markedly increases as the cutting edges of the cutters are worn. This type of sheet material cutting apparatus has a short service life when it is used for cutting a magnetic sheet material for transferring magnetic recordings because it is required to cut a large number of sheets from a roll of magnetic sheet material in this case.

SUMIMARY OF THE INVENTION This invention relates to apparatus for working on paper, fabric and other sheet material and deals more particularly with an improved apparatus for cutting a sheet material.

An object of this invention is to provide an improved apparatus for cutting a sheet material which obviates all the disadvantages of prior art apparatus for cutting a sheet material.

Another object of the invention is to provide an apparatus of the type described in which an annular cutter used as a movable cutter can be made to operate effectively as it is moved along a cutter receiving member which cooperates with it.

Another object of the invention is to provide means for supporting the annular cutter which permits to effect adjustments of the angle of contact between the annular cutter and the cutter receiving member so as to provide the most satisfactory cutting effect.

Additional objects as well as features and advantages of the invention will become evident from the description set forth hereinafter when considered in conjunction with the accompanying drawings.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a perspective view showing essential portions of a prior art apparatus for cutting a sheet material.

FIG. 2 is a schematic perspective view in explanation of the cutting operation of the apparatus according to this invention;

FIG. 3 is a plan view of FIG. 2;

FIG. 4 is a side view of FIG. 2 as seen from the side on which the annular cutter is disposed, with the sheet material shown in FIG. 2 being omitted;

FIG. 5 is a front view showing the relative positions of the annular cutter and the cutter receiving member;

FIG. 6 is a plan view of one embodiment of the cutter receiving member used for cutting a sheet material while the latter is moved;

FIG. 7 is a side view of the apparatus for cutting a sheet material comprising one embodiment of this invention;

FIG. 8 is a side view of FIG. 7 showing the annular cutter being made ready for performing a sheet material cutting operation in its starting position;

FIG. 9 is an enlarged sectional view taken along the line A-A of FIG. 8;

FIG. l0is a plan view showing a portion of FIG. 7;

FIG. 1 1 is a perspective view of means for supporting the annular cutter; and

FIG. 12 is a perspective view of one embodiment of the drive means for moving the annular cutter in reciprocating motion.

DESCRIPTION OF THE PREFERRED EMBODIMENTS In the drawings which illustrate the preferred embodiments of this invention, like reference characters designate similar or corresponding parts. An annular cutter 4 is firmly fixed, by a clamping nut 8, to the outer circumferential surface of a cylindrical member 7 which includes a slightly convex outer circumferential portion 7a (See FIG. 9). Fitted in the bore of the cylindrical member 7 is an outer race of a ball bearing which is secured to the inner wall of the cylindrical member 7 by means of a threaded ring 10 threadably received in the outer opening of the cylindrical member 7. The ball bearing comprises an inner race 9b which is threadably connected, by means of a headed screw 13, to the outer end of a shaft 12 which is loosely fitted, at the inner end, in an opening formed in a spherical member 11. Thus, the cylindrical member 7 to which the annular cutter 4 is attached can rotate freely about the shaft 12.

The spherical member 11 supporting the inner end of the shaft 12 is firmly held between a pivotal plate 16 pivotally connected by a shaft 15 to a first side wall 14a of a sliding member 14 and a keep plate 18 firmly fixed at opposite ends to the pivotal plate 16 by means of two

screws

17, 17. Since the inner end of the shaft 12 is supported by the spherical member 11, it is posible to adjust the direction of the center axis of rotation of the annular cutter 4 so as to provide the most satisfactory sheet cutting effect. The direction in which the shaft 12 is disposed can be adjusted by slightly loosening the

screws

17,17 to provide latitude for rotation of the spherical member 11. Preferably, the shaft 12 which is coaxial with the center axis of rotation of the annular cutter 4 is inclined slightly at a minute angle with respect to a perpendicular to a lateral surface 50 of a cutter receiving member 5 so that a sharp wedgeshaped space S may be formed between the lateral surface 5a and the peripheral edge of the annular cutter 4 as shown in FIG. 3.

An expansive spring 19 mounted between the pivotal plate 16 and a flange 12a (See FIG. 9) of the shaft 12 biases the shaft 12 outwardly (to the right in FIG. 9) so that a portion of the peripheral edge of the annular cutter 4 presses against the lateral surface 5a of the cutter receiving member 5. The cutter receiving member 5 is mounted on the upper part of one side of a rigid supporter 20 fixed to an immovable frame of the apparatus and caused to press thereagainst by a bent lateral edge 21a of a keep plate 21 which is attached to the one side of the supporter 20 by a number of screws 22,22. The bent lateral edges 21a and 21b straddle the cutter receiving member 5 and its supporter 20, so that the cutter receiving member 5 bears strongly against the supporter 20 and is fixed thereto when the screws 22,22 are tightened. The cutter receiving member 5 has an upper end surface 5b which is substantially on the same level as a planar upper surface 200 of the supporter 20.

The convex outer circumferential portion 7a of the cylindrical member 7 moves in rolling motion on the planar upper surface 200 of the supporter 20 during the process of cutting a sheet material by the annular cutter 4 in cooperation with the cutter receiving member 5. The convex outer circumferential portion 7a serves to cause the sheet material to press against the planar upper surface 200 of the supporter 20 and to keep constant the amount of overlapping of the annular cutter 4 and cutter receiving member 5.

A second side wall 14b of the sliding member 14 to which the pivotal plate 16 is pivotally connected (See FIG. 11) is formed with an opening 23 and a cutout 24, and a third side wall 14c thereof of smaller width is formed with an opening 25 which is aligned with the opening 23. A first guide rod 26 loosely extends through the cutout 24, and a second guide rod 27, which is parallel to the first guide rod 26, loosely extends through the aligned openings 23 and 25 (See FIG. 12). The sliding member 14 is adapted to move in sliding motion over the

guide rods

26 and 27 which are secured at opposite ends to the immovable frame of the apparatus. Preferably, bearings providing a friction reducing effect are mounted in the

openings

23 and 25 and cutout 24 for joumalling the

guide rods

26 and 27 to prevent the openings and cutout from coming into direct contact with the guide rods, so that the sliding member 14 may be able to move smoothly over the

guide rods

26 and 27.

A wire 29 trained substantially parallel to the guide rod 27 is fastened in its intermediate portion to a pin 28 connected to the pivotal plate 16 in a position above the shaft 15. FIG. 7 shows the wire 29 as it is pulled to the left, and FIG. 8 shows the wire 29 as it is begun to be pulled to the right. Ifthe wire 29 is pulled to the left, the pivotal plate 16 will be moved in pivotal motion in an anticlockwise direction about the shaft till its vertex 16a abuts against a projection 14d formed in the sliding member 14. As the pivotal plate 16 is moved as aforementioned, the annular cutter 4 is released from engagement with the cutter receiving member 5. Since the annular cutter 4 is normally biased outwardly by the spring 19 (See FIG. 9), the annular cutter 4 tends to be disposed above the cutter receiving member 5 when the former is released from the latter as shown in FIG. 7. This tendency is prevented by a pusher plate 30 mounted in a position in which it is juxtaposed to the outer end of the cylindrical member 7. As shown in FIG. 10, the pusher plate 30 extends to be increasingly spaced apart from the outer end of the cylindrical member 7, so that when the cylindrical member 7 moves in rolling motion from the right in FIG. 10 the pusher plate 30 receives and stops the cylindrical member 7. The pusher plate 30 includes a downwardly extending portion 304 which is fixed to the rear side of the supporter 20 by means of

screws

31,31. Thus, the pusher plate 30 is disposed at one end of the supporter 20 which is a starting position of the annular cutter 4.

As shown in FIG. 12, the wire 29 is attached at one end to a pulley 32 of relatively larger diameter and at the other end to a peripheral groove of a pulley 33 of substantially the same dimension as the pulley 32. The wire 29 is trained over

intermediate pulleys

34 and 35 of smaller diameter so as to maintain the length of wire between the two

intermediate pulleys

34 and 35 parallel to the guide rod 27. The intermediate pulleys also serve to guide the wire 29 so that the opposite ends of the wire are directed to the respective larger diameter pulleys. A length 29a of the wire 29'clisposed between the intermediate pulley 34 and larger diameter pulley 32 and a length 29b of the wire 29 disposed between the intermediate pulley 35 and larger diameter pulley 33 are inclined in opposite directions. The larger diameter pulleys 32 and 33 are secured to opposite ends of a pulley shaft 37 having a gear 36 mounted near one end thereof which gear 36 is adapted to be oscillated by suitable drive means (not shown) without making a complete revolution in either direction.

In operation, if the gear 36 is rotated in the direction of the arrow in FIG. 12, the

pulleys

32 and 33 will rotate in conjunction with each other in the direction of the arrow, with the pulley 32 winding the wire 29 thereon as the wire is paid out by the pulley 33. The wire 29 pulls and moves in the direction of the arrow the pivotal plate 16 carrying the annular cutter 4, so that a sheet material 38 disposed on the cutter receiving member 5 is cut by the annular cutter 4 as it moves thereover in rolling motion. Immediately before the pivotal plate 16 begins to be pulled and moved by the wire 29, the pivotal plate 16 is moved in pivotal motion in a clockwise direction about the shaft 15 as shown in FIG. 8 so as to bring the convex outer circumferential portion into contact with the supporter 20 (See FIG. 9). As the pivotal plate 16 is moved as aforementioned, the annular cutter 4 is spaced apart from the lateral surface of the cutter receiving member 5 as shown in FIG. 10. If the pivotal plate 16 is pulled to the right by the wire 29 at this time, then the end edge 7b of the convex outer circumferential portion 7a is moved away from the pusher plate 30, so that the annular cutter 4 which is substantially integral with the convex outer circumferential portion 7a is urged to move outwardly by the biasing force of spring 19. Thus, the peripheral edge of the annular cutter 4 is caused to press against the upper portion of the lateral surface of the cutter receiving member 5 as shown in FIG. 9. The sheet material can be cut as the pivotal plate 16 is pulled by the wire 29 while the annular cutter 4 and cutter receiving member 5 are maintained in this state.

When the annular cutter 4 has moved to the end of the cutter receiving member 5 after the sheet material is cut, the direction of rotation of the gear 36 (See FIG. 12) is reversed so as to move the pivotal plate 16 in an opposite direction. Means for reversing the direction of movement of the gear 36 may be of any suitable type available. Such means may include a microswitch disposed in a position in which the sliding movement of the sliding member 14 comes to an end, which microswitch is actuated when a portion of the sliding member is brought into contact with the actuating member of the microswitch so as to reverse the direction of rotation of the electric motor. Altematively, a clutch of a conventional type may be used to change the directions of movement of the sliding member.

If the pivotal plate 16 is pulled and moved in an opposite direction by the wire 29 after the sheet material is cut, the pivotal plate 16 will be moved in pivotal motion about the shaft 15 and its vertex 160 (See FIG. 7) will abut against the projection 14d before the sliding member 14 pivotally mounting the pivotal plate 16 is pulled and moved, and then the pivotal plate 16 and sliding member 14 will be pulled and moved in the opposite direction as a unit. when the sliding member 14 is restored to a position shown in FIG. 7, the sliding member 14 produces a command to shut off the wire driving means. During the return movement of the pivotal plate, the annular cutter 4 is maintained in a position in which it is spaced apart from the cutter receiving member 5. This permits to advance the sheet material to the next cutting position while the members including the annular cutter are moved to the starting position. The annular cutter 4 is biased outwardly by the spring 19 while it is spaced apart form the cutter receiving member 5. However, if the members including the annular cutter are restored to the starting position shown in H6. 10, then the end edge 7b of the convex outer circumferential portion 7a is pushed inwardly by the pusher plate 30. Thus, the annular cutter 4 is prevented from striking the cutter receiving member 5 when it is moved again.

If it is required to cut a sheet material disposed over the cutter receiving member while moving the sheet material in one direction, as shown in FIG. 6, one edge of the cutter receiving member 5 has only to be inclined relative to a line drawn across the width of the sheet material 39. In this case, the rate of movement Vp of the sheet material, the linear velocity Vc of the annular cutter 4 moving along the inclined edge of the cutter receiving member 5 and the angle of inclination 0 of the edge of cutter receiving member 5 can be expressed by the following formula:

Sin 0 Vp/V c.

If suitable means for supporting the annular cutter is selected and an edge of the cutter receiving member is formed in a gentle curve, it will be possible to cut the sheet material in the same shape as the curve and, if the sheet material is cut while being moved, it will be possible to cut the sheet material in a shape corresponding to the curve.

Preferably, the material of the cutter receiving member is of higher hardness than the material of the annular cutter. If the annular cutter is caused to press against the cutter receiving member with a relatively great force, the sheet material can be cut easily even if an upper edge 5c of the cutter receiving member 5 is worn and rounded as shown in FIG. 5. The old and worn cutter receiving member 5 can be readily replaced by a new one by loosening the clamping screws 22,22. The old and worn annular cutter 4 can be readily replaced by a new one by removing the screw 13 threaded into the shaft 12 (See FIG. 9).

The cutter receiving member may conveniently be in the fonn of a web having a greater length than the effective length of the cutter receiving member. This permits to obviate the time-consuming operation of replacing the worn cutter receiving member by a new one, because the web can be pulled in one direction to bring a new portion into engagement with the annular cutter when the portion of the web serving as a cutter receiving member is worn. Preferably, the material of this web-like cutter receiving member is highly resilient, as in the case with the material of the coiled spring of a clock, because it is convenient to handle, since it can be wound in convolutions at opposite ends of the portion of the web used as a cutter receiving member.

If the annular cutter is not released from engagement with the cutter receiving member when the former is returned to its starting position or if the annular cutter can be moved in reciprocating motion while being maintained in pressing engagement with the cutter receiving member, then it is possible to cut a sheet material by the annular cutter in both its advance movement and its return movement. If a disc is used as a cutter receiving member and the annular cutter is caused to press against its peripheral edge, then it is possible to cut a sheet material in the circular form. Means for driving the annular cutter in this case may include a rotary shaft axially extending through the center of the disc and mounting an arm which supports the annular cutter. It will be evident to one having an ordinary skill in the art that the annular cutter can be used in many different ways within the scope of the present invention.

What is claimed is:

1. An apparatus fur cutting a sheet material comprising a cutter receiving member disposed to extend across the width of the sheet material in contact with one surface thereof, an annular cutter rotatably mounted on a shaft arranged nearly normal to an edge of said cutter receiving member so that said annular cutter presses at a portion of its peripheral edge against said edge, means supporting said shaft, and drive means operable to reciprocate said supporting means along said cutter receiving member; said supporting means including a pivotal plate supporting said shaft; a sliding member pivotally supporting said pivotal plate for pivoting about an axis in laterally spaced parallel relation to said shaft; and means slidably supporting said sliding member for reciprocation along said cutter receiving member; said drive means including an elongated element extending substantially parallel to said cutter receiving member and connected to said pivotal plate at a point thereon substantially vertically above the pivot axis of said pivotal member; whereby, when said element is moved in one direction along said cutter receiving member, said pivotal plate is pivoted to swing said annular cutter downwardly into cooperating relation with said cutter receiving member and, when said element is moved in the opposite direction along said cutter receiving member, said pivotal plate is moved in a direction to lift said annular cutter away from said cutter receiving member; and means engageable with said pivotal plate to limit pivoting thereof in a direction to retract said annular cutter from said cutter receiving member.

2. An apparatus for cutting a sheet material, as defined in claim 1, including a cylindrical member substantially fixed with respect to said annular cutter to rotate therewith, said cylindrical member projecting over the upper surface of said cutter receiving member and limiting the amount of overlapping of said annular cutter and said cutter receiving member.

3. An apparatus for cutting a sheet material, as defined in claim 1, in which said means slidably supporting said sliding member comprises guide rods extending substantially parallel to said cutter receiving member.

4. An apparatus for cutting a sheet material, as defined in claim 1, in which said elongated element comprises a wire.

5. An apparatus for cutting a sheet material comprising a cutter receiving member disposed to extend across the width of the sheet material in contact with one surface thereof, an annular cutter rotatably mounted on a shaft arranged nearly normal to an edge of said cutter receiving member so that said annular cutter presses at a portion of its peripheral edge against said edge, means supporting said shaft, and drive means operable to reciprocate said supporting means along said cutter receiving member; said supporting means comprising a pivotal plate supporting said shaft; a sliding member pivotally supporting said pivotal plate for pivoting about an axis disposed in laterally spaced parallel relation to said shaft; guide rods supporting said sliding member for reciprocation parallel to said cutter receiving member; a wire extending substantially parallel to said cutter receiving member and secured at an intermediate portion thereof, to said pivotal plate at a point disposed substantially vertically above the pivot axis of said pivotal plate; said drive means comprising means operable to reciprocate said wire substantially parallel to said guide rods; said wire, when moving in one direction parallel to said guide rods, pivoting said pivotal member to overlap said annular cutter with said cutter receiving member and, when moved in the opposite direction, pivoting said pivotal member to retract said annular cutter out of overlapping relation with said cutter receiving member; said support means further including a cylindrical member substantially fixed with respect to said annular cutter to rotate therewith, and adapted to engage the upper surface of said cutter receiving member to limit the amount of overlapping of said annular cutter and said cutter receiving member; stop means engageable with said pivotal member to limit the pivoting thereof in a direction retracting said annular cutter from overlapping relation with said cutter receiver member; a spring positioned between said annular cutter and said pivotal plate and baising said annular cutter to engage a portion of its peripheral edge against the lateral surface of said cutter receiver member; and a pusher plate fixed with respect to said cutter receiving member at one end thereof and having a free end inclined with respect to the direction of movement of said annular cutter when said annular cu r is retracted from overlapping engagement wi sai cutter receiving mem r;

said pusher plate engaging the outer end of said cylindrical member to move said cylindrical member toward said pivotal plate against the bias of said spring.

6. An apparatus for cutting a sheet material comprising a cutter receiving member disposed to extend across the width of the sheet material in contact with one surface thereof, an annular cutter rotatably mounted on a shaft arranged nearly normal to an edge of said cutter receiving member so that said annular cutter presses at a portion of its peripheral edge against said edge, means supporting said shaft, and drive means operable to reciprocate said supporting means along said cutter receiving member; said supporting means including a spherical member formed with an opening loosely receiving said shaft so that said spherical member constitutes a bearing for said shaft; and means supporting said spherical member for angular displacement to adjust the angular relation of said shaft to said cutter receiving member.

7. An apparatus for cutting a sheet material as defined in claim 4, including a pulley to which one end of said wire is fastened; a second pulley, of the same diameter as said first-mentioned pulley, to which the other end of said wire is connected; a pulley shaft having said two pulleys mounted at respective opposite ends thereof; and means operable to rotate said two pulleys in selected opposite directions.

8. An apparatus for cutting a sheet material as defined in claim '7, in which said shaft extends substantially parallel to said cutter receiving member; said pulleys being fixedly secured to opposite ends of said shaft for conjoint rotation in the same direction; said wire being secured to said pulleys in a direction such that it is wound on one pulley while being unwound from the other pulley responsive to rotation of said shaft; said driving means being operable to rotate said shaft in opposite angular directions to reciprocate said wire along said cutter receiving member.

# i I 1 i

Claims

5. An apparatus for cutting a sheet material comprising a cutter receiving member disposed to extend across the width of the sheet material in contact with one surface thereof, an annular cutter rotatably mounted on a shaft arranged nearly normal to an edge of said cutter receiving member so that said annular cutter presses at a portion of its peripheral edge against said edge, means supporting said shaft, and drive means operable to reciprocate said supporting means along said cutter receiving member; said supporting means comprising a pivotal plate supporting said shaft; a sliding member pivotally supporting said pivotal plate for pivoting about an axis disposed in laterally spaced parallel relation to said shaft; guide rods supporting said sliding member for reciprocation parallel to said cutter receiving member; a wire extending substantially parallel to said cutter receiving member and secured, at an intermediate portion thereof, to said pivotal plate at a point disposed substantially vertically above the pivot axis of said pivotal plate; said drive means comprising means operable to reciprocate said wire substantially parallel to said guide rods; said wire, when moving in one direction parallel to said guide rods, pivoting said pivotal member to overlap said annular cutter with said cutter receiving member and, when moved in the opposite direction, pivoting said pivotal member to retract said annular cutter out of overlapping relation with said cutter receiving member; said support means further including a cylindrical member substantially fixed with respect to said annular cutter to rotate therewith, and adapted to engage the upper surface of said cutter receiving member to limit the amount of overlapping of said annular cutter and said cutter receiving member; stop means engageable with said pivotal member to limit the pivoting thereof in a direction retracting said annular cutter from overlapping relation with said cutter receiver member; a spring positioned between said annular cutter and said piVotal plate and baising said annular cutter to engage a portion of its peripheral edge against the lateral surface of said cutter receiver member; and a pusher plate fixed with respect to said cutter receiving member at one end thereof and having a free end inclined with respect to the direction of movement of said annular cutter when said annular cutter is retracted from overlapping engagement with said cutter receiving member; said pusher plate engaging the outer end of said cylindrical member to move said cylindrical member toward said pivotal plate against the bias of said spring.

8. An apparatus for cutting a sheet material as defined in claim 7, in which said shaft extends substantially parallel to said cutter receiving member; said pulleys being fixedly secured to opposite ends of said shaft for conjoint rotation in the same direction; said wire being secured to said pulleys in a direction such that it is wound on one pulley while being unwound from the other pulley responsive to rotation of said shaft; said driving means being operable to rotate said shaft in opposite angular directions to reciprocate said wire along said cutter receiving member.