US2365663A - Strip cutter - Google Patents

Description

Dec. 26, I944.

A, TORRESE 2 ,365,663

STRIP CUTTER Filed Jan. 21, 1945 2 Sheets-Sheet 1 I I 20 o 0 I6 0 l o t I I as. -|l 1 I N r I A v .Fi'g. 1.

vmvmon a Ape/lo Torre UBYWW Dec. 26, 1944.

' A. TORRESE 2,365,663

STRIP CUTTER Filed Jan. 21, 1945 2 Sheets-Sheet 2 INVENTOR Apollo Torrese BY Patented Dec. 26, 1944 Apollo Torrese, Philadelphia, Pa., assignor to A. P. de Sanno & Son, Inc., a. corporation of Pennsylvania Application January 21, 1943, Serial No. 473.056

4 Claims. (01. 164-42) Myinventlcn relates toa" cutter and relates more particularl tof a cutter for cutting a thin sheet of metalstrips.

Metal-based abrasive strips comprising a thin flexible metal backing with a granular abrasive attached to the backing by means of a suitable adhesive are in general use by the dental profession. Heretofore these strips of abrasivehave been cut by hand in the following manner:

The'abrasive, which is produced in sheet form, would be out by a hand-operatedcutter into strips about /8 of an inch wide and about 6 inches long. Since thestrip width would thus depend upo'n'the skill of the operator it is apparent that the accuracy in estimating the cut would inge'neral not'b very great. Because a more accurate method has heretofore not been available, the industry had been forced to use such strips of non-uniform width. Automatic machines for producing these strips have heretoforebeen unsuccessful in properly cutting to desired Widths, they have lacked facility and speed of changing parts or replacement of a suitable cutter, and havebeen relatively very complex.

The primary object of my invention is to produce amachine in which these defects are overcome.

Another object of myinvention to provide a cutting machine for metal backed abrasives, which is simple in construction and design.

A further object of my invention is to provide a simple metal-based abrasive cutting machine which cuts strips to accurate widths.

Still another ob'iect of my invention is to produce a cutting machine which is inexpensive to manufacture and to operate.

The invention, both as to details of construc tion and combination of parts will best be understood from the following description of aspecific embodiment which. I illustrate as an example,v

when read in connection with the accompanying drawings, in which;

Fig. 1 shows a perspectiveview of my invention.

Fig. 2 showsa top plan view of the base assembly.

Fig. -3 is a fragmentary sectionalview taken on the line 3 ,-3 of Fig. 2.

Fig. 4 is a perspective view showing the cutting knife and driving wheel in detail,

Referring now to the drawings, I show in Fig. 1 a basegenerallydesignated as A. The base A is preferably mounted on a suitable stand or table for convenience of the operator and to provide vertical clearance for a gravity-operated fixed to the plate l6 and extending through I sheet advancing mechanism subsequently to be described in detail. Mounted on the base A is an assembly comprised essentially of a slide 13, a brake C, a knife or cutter D, a driving wheel E and a stop F.

The base A'has a. longitudinal slot Hi crossshaped in section and cut centrally in the top surface I2. The slide B comprises a cross-shaped member Hi to which is attached a flat plate l6 mounting a sheet-holder l8. The member M is constructed and arranged to slide freely Within the slot Ill and to move the plate It longitudinally to and flatwise to the surface I2 with a minimum of sliding friction. Mounted longitudinally on base A to either side of the slot H! are fixed guides 28 and 22 which serve to guide the plate It and ,the abrasive sheet 40 carried thereon.

The holder l8 comprises a sheet metal plate having two longitudinal cuts in the front edge 24 and having the portion between the cuts bent downwardly at a small angle to provide a bifurcation for holding the sheet of abrasive. The holder IB is pivotally mounted at approximately its. center on a pin 26 extending upwardly from the plate 16 so that the leading or bifurcated edge 24 can be tilted, up or down. The edge 2-4 is biased in the downward position by means of a helical compression spring 28 between the plate I6 and the trailing endof the holder l8, the spring 28 being held in place by a second pin the spring 28 and an aligned hole in the holder it.

The slide B is constantly urged forward by means of a weight 29 hanging below the base A onthe end of a cord 36 which passes upwardly into anopening 32 near the front of the base A and communicating with the slot Ill, over a pulley 34, backwardly along the slot l8, and finally is attached to the leading end of the member Id.

The. brake C for holding the abrasive'sheet 48 is disposed across the front of the base A and is attached to one sidethereof by a hinge 36. The other end of the brake C is held down under compression by an adjustable resilient clamp 38. The brake C is suitably provided with slots for the guides 20 and 22 so that it does not come into contact with these guides, and is arranged to be biasedslightly upward so that the abrasive sheet may pass freely beneath it when said sheet is not held down by the clamp 38.

The cutter or knife D is pivotally mounted at the front of the base A on the same side as the clamp38, said clamp 38 projecting forwardly out over theknife so that it is lifted to release the pressure on the brake C when the knife is raised. The other end of the knife is linked to the drive wheel E by a connecting rod 42 so that the knife is cyclically raised and lowered as the wheel E is turned by a pulley 44 on the same shaft 46 with the wheel E. The pulley 44 is driven by a belt from any convenient prime mover (not shown).

Attached centrally to and on the front side of the knife D is a. cam 48 which, at the lower part of the stroke, comes into contact with a cam follower 58 forcing the latter to move in a frontward direction. The follower 50 is attached to the stop F by locking slot and pin connections 52 so that it can be fixed relative to said stop for the particular adjustment desired. The stop F rests transversely to base A on front exten sions 54 of said base and is mounted on two rods 58 for sliding movement longitudinally of base A. The rods 56 are fixed in base A, are threaded at the forward ends and are equipped with compression springs 58 and wing nuts 68 so that the stop F can be adjusted in the desired position. The stop F is constructed so that it presents a flat surface to the edge of the advancing abrasive sheet, the follower 58 being above this level and adapted to contact the cam 48 only.

The operation of this device is as follows:

A sheet of abrasive 40 is placed in the holder 18 and allowed to be moved by the gravity actuated slide B into contact with the rear side of the brake C if the brake is down or into contact with the stop F if the brake C is raised. The stop F and the associated cam follower 58 having previously been adjusted for desired width of the cut strip, the wheel E is placed in rotation, moving the knife D up and down. As the knife is raised from an initially lowered position, the clamp 38 is sprung upwardly thereby, thus releasing the brake C and permitting the slide B to move ahead until the sheet 40 contacts the stop F. As the knife lowers, the clamp 38 presses down on the brake C to hold the sheet 40 after which the cam 48 forces the follower 50 and with it the stop F forwardly, leaving the stripfree to be cut off by the continuing downward movement of the knife. With the stop F pushed out of the way, there is no back pressure on the work-piece permitting an easy cut and allowing the cut strip to freely fall down into a suitable receptacle (not shown). As the knife moves upwardly on the next cycle, the brake is again released, permitting the sheet 48 to be moved ahead the width of the strip, and the cycle is repeated as above.

My invention is described as particularly adapted to cutting metal-backed abrasives, but it is equally adapted for cutting strips of any sheet material.

Although I have described the device as operated by a belt drive, it is obvious that it may be powered by an integral motor or any other suitable mechanical drive, or it may be operated by manually turning the wheel E or its equivalent. Furthermore, for best accuracy and for predetermining exactly the width of strip I prefer the springs 58 to be strong enough so that they are not compressed by the pressure of the sheet 48 as it is moved ahead by the slide B, but it is obvious that if a weaker spring is used it will be compressed an equal amount each time so that the device will still turn out strips of uniform width.

Although my invention has been described in considerable detail, such description is intended as illustrative rather than limiting as numerous embodiments will be apparent to those versed in the art. My invention, therefore, is not to be limited except insofar as is necessitated by the prior art or the scope of the appended claims.

I claim:

1. In a machine for' cutting sheet material, the combination of a base having a flat surface for reception of the sheet to be cut, a knife pivotally attached to said base for oscillatory movement in a, plane transverse to said surface and arranged to wipe the front edge thereof in cutting relation to said sheet, means for oscillating said knife, means for presenting said sheet in position before the knife begins the cutting stroke for cutting a strip therefrom, said second named means includes a braking member for holding the sheet in place during the cutting stroke and to release said sheet during the upstroke of the cutter, and a clamping member arranged to apply pressure on said braking member while the knife is in cutting engagement and to be released from said braking member when the knife is in retracted position, said braking member being biased to be out of engagement with the sheet when not compressed thereon by said clamping member, and a stop for engaging the frontend of the sheet for limiting the forward movement of said sheet.

2. In a machine for cuttin sheet material, the

combination of a base having a fiat surface for reception of the sheet to be cut, a knife pivotallyv attached to said base for oscillatory movement in a plane transverse to said surface and arranged to wipe the front edge thereof in cutting relation to said sheet, means for oscillating said knife, means for presenting said sheet in position before the knife begins the cutting stroke for cutting a strip therefrom, said second named means includes a braking member for holding the sheet in place during the cutting stroke, a clamping member arranged to apply pressure on said braking member whereby to hold the sheet firmly in place while the knife is in cutting engagement and to be released from said braking member when the knife is retracted from cutting engagement. said braking member being biased to be out of engagement with the sheet when not compressed thereon by said clamping member, a mechanism for advancing the sheet While the knife is retracted from cutting engagement, a stop for adjustably limiting the forward travel of said sheet, and third means for moving said stop out of engagement with said sheet during the cutting stroke.

3. In a machine for cutting sheet material,

' the combination of a base having a flat surface for reception of the sheet to be cut, a knife pivotally attached to said base for oscillatory move- 4 ment in a plane transverse to said surface and arranged to wipe the front edge thereof in cutting relation to said sheet, means for oscillating said knife means for presenting said sheet in position before the knife begins the cutting stroke for cutting a strip therefrom, said base being provided with a longitudinal slot, and said second means including a mechanism for advancing the sheet while the knife is retracted from cutting engagement comprising a member slidable within said slot, a plate fixed to said member and adapted to be moved longitudinally to and flatwise of said surface, a sheet holder fixed to said plate and adapted to hold the sheet in position on said surface, and third means for applying to said member a force continuously urging it in a forward direction.

4. In a machine for cutting sheet material, the combination of a base having a flat surface for reception of the sheet to be cut and a longitudinal slot in said surface, a knife pivotally attached to said base for oscillable movement in a plane transverse to said surface and arranged to wipe the front edge thereof in cutting relation to said sheet, means for oscillating said knife cyclically in alternate cutting and retracting strokes, a braking member pivotally attached to said base and adapted to be pressed down on the sheet to hold it in place during the cutting stroke, a clampin member arranged to apply pressure on the free end of said braking member during the cutting stroke and to be released from said braking member during the retracting stroke,

said braking member being biased to be out of engagement with the sheet when not pressed down thereon by the clamping member, a mechanism for advancing the sheet during the retracting stroke comprising a slide member slidable within said slot, a plate fixed to said slide member and adapted to'be moved longitudinally to and fiatwise of said surface as said slide member moves Within said slot, a sheet holder fixed to said plate and arranged to hold the sheet fiatwise in position on said surface as said sheet is advanced over said surface, and means for continuously urgin said slide member in a for- Ward direction, a stop for adjustably limiting the

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