US2070469A - Lift cutting die and process - Google Patents

Description

Feb. 9,1937. F. EXLEY v LIFT CUTTING DIE AND PROCESS Filed July 18, 1936 2 Sheets-Sheet 1 Feb. 9, 1937. 1.. F. EXLEY LIFT CUTTING DIE AND PROCESS Filed July 18, 1936 2 Sheets-Sheet 2 w ri Patented Feb. 9, 1937 PATENT ()FFIQE LIFT CUTTING DIE AND PROCESS Leo F. Exley, Johnson City, N. Y., assignor to Endicott Johnson Corporation, Endicott, N. Y., a corporation of New York Application July 18, 1936, Serial No. 91,385

5 Claims.

This invention includes a novel cutting die, and novel feeding mechanism for use in connection with the die. The novel die is particularly designed for blanking or cutting out all sheet materials used in the construction of shoes or footwear, such as heel lifts, box toes, counters, heel reinforcing pieces, linings or any other part of a shoe, especially those blanks which have one straight, or substantially straight edge, and one object of my invention is to reduce waste of material and enable more blanks to be cut from a given size of sheet than has heretofore been possible.

Another object is to provide improved means for feeding the sheet of material to and between the die and cutting block.

The blank cutting machine commonly used has a reciprocable plunger carrying a cutting block adjustable in relation to a blank cutting die mounted on a support below the cutting block, such support having an opening approximately of the same shape and usually larger than the cutting edge of the die. When such machine is in operation the plunger is reciprocated up and down, and the sheet of material, such as leather board, from which the blanks such as heel lifts or the like are to be cut, is intermittently fed or pushed between the cutting die and block by feed rolls; and blanks are successively cut out of the sheet adjacent the inner edge of the material and pass down through the die and its support.

In such machine the feed rolls are located in advance of the die (in relation to the direction of travel of the sheet being cut) and on the shafts of the feed rolls are discs which separate the portion of the sheet from which the blanks are to be cut from the body of the sheet, as and before the successive blanks are cut therefrom.

The discs in separating the strip from the main portion of the sheet, break and crush the adjacent edges of the strip and sheet, and so disturb and displace the fibres therein as to form a considerable useless spongy margin on both the strip to be cut and on the adjacent edge of the sheet, which edge must be presented to the back gauge in the next subsequent cutting operation. Due to the production of such spongy margins, the shearing discs must be so located in relation to the cutting die that a sufficiently wide margin must be left uncut on each side of the strip in order that no portion of the spoiled margins may be included in the cut blank. Such comparatively wide margins heretofore necessarily left on both sides of the strip from which the blanks are cut result in a high percentage of waste material.

My invention overcomes and eliminates the waste and defects in the present blank cutting mechanism. One essential of my invention is the peculiar construction of the cutting die and another the novel arrangement of the stock feeding mechanism. To enable others to understand and utilize my invention I will explain the same with reference to the accompanying drawings which illustrate a practical embodiment of my invention, and in the claims the essentials of the invention and novel features of construction and combination of parts for which protection is desired are summarized.

In said drawings:

Fig. 1 shows parts of a lift cutting machine equipped with my improvements. Fig. 2 is a plan of the cutting die. Fig. 3 is a top view of the die. Fig. 4 is a sectional view of the die on the line 4-4, Fig. 3. Fig. 5 is a diagrammatic figure illustrating the action of my invention. Fig. 6 is a detail view of part of a lift strip cut by my machine. Fig. '7 is a detail view of a lift strip cut by the heretofore used machines. Fig. 8 is a view of a plural lift cutting die; and Fig. 9 is a view of a part of the strip cut by die H.

The cutting die While I do not limit my invention to the cutting of heel lifts, I have shown parts of a heel lift cutting machine and die in the drawings as an illustration of one embodiment of the invention primarily because such heel lift blanks are usually cut from leatherboard and have at least one straight, or nearly straight, edge.

The lift cutting die as shown in Figs. 2, 3 and. 4 has a body portion I conforming in contour to the lift to be cut, and has a projection la at one straight or nearly straight side extending in line with suchstraight side. The extreme end lg of the projection la. is curved in slightly to insure a positive and complete cut-off in event the position of the board is slightly altered in its passage through the machine by careless handling. Said die is provided at its base with a perforated projecting lug le and flange If for engagement of bolts l h by which it is attached to the base Ik. Fig. 1.

In setting-up the machine preparatory to operation, the die is set so that the straight portion of the side of the die and the projection Ia will be exactly parallel to the direction of travel of the sheet, and as the sheet progresses through the machine lifts are out and at the I same time the projection Ia cuts off the small irregular shaped piece left by the preceding lift cut-out. The cooperation of the projection la and the adjacent straight side of the die leaves the edge of the body of the sheet straight and true and in perfect condition to be placed di rectly against the back gauge and repeat the operation just described.

The die is mounted upon the table of support 2 of the die cutting machine, in the usual manner (see Fig. 1). As the lift cutting machines are well known I have illustrated only so much of such machine as is necessary to enable those familiar with the art to understand and use my invention.

The recip-rocable plunger 3 above the die carries a cutting block 3a adapted to cooperate with the die in cutting lifts from the sheet of material fed therebetween. A pair of feed rolls 4, at the infeed side of the 'die are adapted to advance the sheet of material to be cut, intermittently between the die and cutting block, after each cutting operation of the die. The feed rolls 4 are mounted on shafts 4a which are intermittently operated to feed the sheet as described, but such mechanism forms no part of my invention and is not illustrated.

In advance of the feed rolls a table 5 is provided on which the sheet to be fed is placed by the workman, the inner edge of the sheet being positioned against a guide Ed at the rear side of said table.

In my invention I provide the said machine with auxiliary sheet feeding means, preferably employing a pair of rolls 6 located at the side of the die opposite rolls 4. Rolls 6 are adapted to pull the sheet between the die and block,-see Figs. 1-3. Rolls 6 are mounted on shaft 6a, and may be driven in unison with and from rolls 4 as described in my divisional application filed November 30, 1936, Serial No. 113,523.

The rolls 6 ensure the sheet passing properly and entirely past the die, and enable a lift to be cut from the heretofore waste stub on the rear end of the strip.

A sheet guide could be attached tothe shaft of the lower feed roll 6, but as such shaft is capable of a limited up and down motion, and the feed roll mounted on this shaft is held in contact with the board by the pressure spring, I prefer to support the guide on the upper shaft.

The sheet guide and the back gauge 5a form two points of contact which insures under normal conditions a true straight progression through the machine of the sheet being cut, more particularly because my improved die leaves a straight true uninjured edge on the sheet, which edge next comes in contact with the guides.

To further explain the feed, the feed rolls 4 push the sheet to die for the first cut; the set of rolls 6 engage the sheet as it progresses past the die and pull the sheet entirely past the die; and both sets of rolls are utilized in order to accomplish the cutting-up of the entire strip, including a last-cut in the last end of the strip which has heretofore always been waste.

The procedure followed in cutting up a sheet of board on a machine equipped with my improved die and feeding arrangements is as follows:

First the straight hard satisfactory edge of an uncut sheet is placed against the back gauge and moved forward over the cutting die and engaged by the feed rolls. The downward thrust of the cutting block cuts out of the sheet a lift (see Fig. 5) and at the proper time during the up-stroke of the plunger and cutting block the feed. rolls 6 pull over the die a new uncut portion of the board. The reciprocating motion of the cutting block and intermittent motion of the feed rolls, properly timed in relation to each other, causes the sheet to pass between the cutting block and the cutting die for its entire length, and results in a series of lifts being cut-out and leaves a strip of scrap as shown in Fig. 6. Fig. '7 shows a strip of scrap as out by the heretofore known machines.

Comparing the scrap shown in Fig. '7 with the scrap shown in Fig. 6 it will be observed that there is no margin left on the side of the scrap Fig. 6 like that shown at S in Fig. 7. The size of the pieces of scrap are further reduced by my die, as the straight side or breast of the die is extended by the projection la, so that automatically each section left by a lift being cut out is cut in two and the resultant scrap is in effect chopped-up and partly prepared for the fibre beating machines to which it is generally consigned.

By my invention I have eliminated one waste margin which is inevitable with the arrangement and machines now in use, and furthermore because the edge of the remaining portion of the sheet is left straight true and firm and not broken, I am able to so adjust the gauges in relation to the edge of the die that only a very narrow margin is required for the cutting die to enter, as compared to What is now required with present arrangements.

In machines now in use, as before described, the feed rolls in effect push the stock to the die. These feed rolls 4 engage the main uncut portion of the board and inasmuch as in the machine, as at present arranged, the strip being cut is sheared or broken before coming to the die, there remains on each end of scrap an uncut piece S, of board large enough to form a lift (see Fig. 7) as no means is provided for carrying the same to and over the die. My die and machine arrangement pulls in, and cuts a lift from this piece S (see Fig. 6).

I have applied the extended projecting cutting edge Ia to double dies, such for example as shown in Fig. '8. By my invention I produce a better quality of product in that the sheet is out only with a sharp cutting edge and not broken anywhere, each lift cut from the board being firm and all edges of lift and sheet remain hard and true.

By my invention I get out of a given siZe sheet more lifts than heretofore, and further, the scrap resulting from the use of my die and machine is in smaller pieces and therefore more of it can be loaded by weight in a given size of container, and this facilitates the handling and transportation or disposition of such scrap.

I am aware that extension edges and protruding cutters have been used. Such construction is known to the cutting-die industry as chisels and is invariably used to reduce the size of scrap, or to facilitate the removal of the out parts from the surrounding material; but never to my knowledge has any die been provided with a projection for the express purpose of preparing the portion of material being cut for a subsequent repeated operation. My construction does this, leaving the edge of the uncut portion of material in perfect condition to insert in the machine, and to repeat such operations until the entire sheet has been cut up.

Cir

There are only two methods of mechanically cutting heel lifts. In one system of cutting lifts the sheet of material is stripped or cut to narrow widths in a separate operation, previous to feeding through the cutting machine. In the other system the stripping operation is accomplished by discs or shears, and this operation takes place just before the cutting operation. In either system, a margin is required which becomes scrap. In my invention there is no stripping or separation of the board in any way; the portion of the sheet being cut is at all times a part of the original. This is of distinct advantage when cutting two or more superposed sheets which have been fastened together.

In the cutting of any given size of blank, using a sharp edged cutting die of the usual construction, it is absolutely necessary to have a piece of the material being cut of larger dimension than the die-a considerable amount of the stock must surround the entire outline of the cutting edge. This is required in order to give the cuttingedge an entrance or bite into the stock. If an attempt is made to cut a blank and not have marginal stock surrounding the outline of the die, the die will be driven through the stock in a slantwise manner, moving downward, and at the same time, sideways toward the edge which is not entered or engaged in the stock. The result is to cut a blank whose edges will not be at right angles to the surface, and such blank is generally distorted and not of the same shape as the die. This is due to natural laws and cannot in any way be overcome. My construction complies with this requirement, but with this difference as compared to the usual procedure. That portion of the sheet which is engaged by the projection on the die serves its purpose in guiding the die and then becomes the guiding edge for the subsequent cut and is not discarded as is done at present.

I do not herein claim the machine, as that forms the subject-matter of a divisional application filed November 30, 1936, Serial No. 113,523.

I claim:

1. A blank cutting die having a projection at one side in line with a side and adapted to cut a slit in the sheet in advance of the opening in the sheet cut by the die, said slit extending sufficiently to register with the side of the opening cut in the sheet at the next successive operation of the die thereon, whereby a straight clean cut edge is formed on the sheet.

2. A blank cutting die having a substantially straight side and having a projection at one side in line with such side and adapted to cut a slit in the sheet in advance of the opening in the sheet cut by the die, said slit extending sufiicient- 1y to register with the side of the opening cut in the sheet at the next successive operation of the die thereon, whereby a straight clean cut edge is formed on the sheet, the extreme end of said projection being slightly incurved.

3. A blank cutting die having a substantially straight side and having a projection at one side in line with such side and adapted to cut a slit in the sheet in advanace of the opening in the sheet cut by the die, said projection and adjacent straight side of the die producing a straight true edge on the sheet adjacent the line of perforations made by the die.

4. A blank cutting die having a substantially straight side and having a projection at one side in line with such side and adapted to cut a slit in the sheet in advance of the opening in the sheet cut by the die, said slit extending sufficiently to register with the side of the opening cut in the sheet at the next successive operation of the die thereon, whereby a straight true edge is left on the sheet adjacent the line of perforations made by the die, and the perforated strip is severed from the sheet without marginal waste between the adjacent edges of the cut strip and the sheet.

5. The method of cutting blanks from sheets; consisting in cutting a blank from the sheet and simultaneously cutting a slit in the sheet in advance of the opening left by the removed blank, said slit extending suificiently to register with the side of the next opening cut in the sheet at the next successive cutting operation, said slit forming with the adjacent straight edges of successive cuts a straight true edge on the sheet adjacent the line of openings made by the cuts; whereby the perforated cut strip is removed from the sheet without marginal waste between the adjacent edges of the cut strip and the remainder of the sheet from which the strip is cut.

LEO F. EXLEY.

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