US3668959A

US3668959A - Process and device for advancing and simultaneously centering sheet material

Info

Publication number: US3668959A
Authority: US
Inventors: Wolfgang Max Egon Richter; Edgar Lab; Hans Werner Sieblist
Original assignee: Schmalback Lubeca AG
Current assignee: Ardagh Metal Beverage Germany GmbH
Priority date: 1969-08-12
Filing date: 1970-08-12
Publication date: 1972-06-13
Anticipated expiration: 1989-06-13
Also published as: DE1940912A1; DE1940912B2; DE1940912C3

Abstract

This disclosure relates to a scroll cutting apparatus which is provided with a feed mechanism which automatically assures centering of the sheet material upon each advance thereof prior to the actuation of the scroll cutter. The feed mechanism includes a first feed disposed in advance of the scroll cutter and a second feed between the scroll cutter and a centering stop. Each feed has associated therewith guide means engaging the opposite edges of the sheet material with one half of each guide means being fixed and the other half being resiliently mounted. The feed mechanism includes rollers which rotate to advance the sheet material and which are hunted axially thereof so as to transversely hump the sheet material in cooperation with the guide means so as to perfect the centered feeding of the sheet material.

Description

Unite States atent Richter et al.

[4 1 June 13, 1972 [73] Assignee: Schmalbach-Lubeca-Werke [72] Inventors: Wolfgang Max Egon Richter; Edgar Lab;

Hans Werner Sieblist, all of Seesen, Germany Aktiengesellschait, Braunschweig, Germany 22 Filed: Aug. 12, 1970 21 Appl.No.: 63,117

[58] Field ofSearch ..83/32, 36, 42,48, 251,253, 83/420 [56] References Cited UNITED STATES PATENTS 3,446,499 5/1969 Ringler ..83/25l X 3,599,521 8/l97l Lee ..83/25lX 3,600,992 8/l97l Dryon ..83/25lX Primary Examiner-Andrew R. J uhasz Assistant Examiner-David R. Melton Attorney-Dil|er, Brown, Ramik & Holt [5 7] ABSTRACT This disclosure relates to a scroll cutting apparatus which is provided with a feed mechanism which automatically assures centering of the sheet material upon each advance thereof prior to the actuation of the scroll cutter. The feed mechanism includes a first feed disposed in advance of the scroll cutter and a second feed between the scroll cutter and a centering stop. Each feed has associated therewith guide means engaging the opposite edges of the sheet material with one half of each guide means being fixed and the other half being resiliently mounted. The feed mechanism includes rollers which rotate to advance the sheet material and which are hunted axially thereof so as to transversely hump the sheet material in cooperation with the guide means so as to perfect the centered feeding of the sheet material.

12 Claims, 4 Drawing Figures PATENTEDJuu 13 I972 m H w an A r T wdHH 2 m 0 9 om ,0 A. v i W h W T M H T main 8 mm m z 7 3 N N m /2 5 55 m V 2R 7 N w M4 2 E m um Q M W E K m m M Di m w m 2 Q 70mm PROCESS AND DEVICE FOR ADVANCING AND SIMULTANEOUSLY CENTERING SHEET MATERIAL The invention relates to a process and the device for feeding and simultaneously centering sheet material, especially coil sheet metal, toward a fixed centering stop on the side of the front edge of the sheet metal as an initiation of the true-to-size cutting of the coil sheet metal in a scroll cut to be formed in a conventional manner into sheets for further processing into stamped metal parts with cutting surfaces curved on all sides, and with the coil sheet metal being fed through the use of a coarse and fine feed separately transporting and guiding the sheet laterally.

BACKGROUND OF THE INVENTION Since in the case of production of stamped metal parts we are dealing, generally speaking, with a definite mass production and in large numbers, a reduction in costs of these articles is' possible only by an improvement within the framework of the manufacturing process. For that reason, others have replaced the purchase of precut sheets of a certain size with the purchase of coil sheet metal, generally referred to as coils. Rolling mills are not in a position to supply the coil material more cheaply than the sheets.

In the manufacture of stamped metal parts with cutting surfaces curved on all sides, for example, covers or bottoms of cans or similar articles, the strips herebefore have been cut transversely to the feed direction into sheets with straight cutting edges. The covers or bottoms then were cut from these sheets in sequences of stamped parts arranged correspondingly displaced in relation to one another. At the trimmed ends of the sheets, in that case there developed half cut-outs, which naturally were not usable and therefore considerably'increased the waste. The half cut outs furthermore brought about the danger of an easier damage to the stamping tools. l

In the course of the further improvements, others moved on to cutting the sheets that were to be cut from the coil in a socalled scroll cut, that is to say, the strip was cut transversely to its longitudinal extent in such a manner that zig-zag shaped cutting edges resulted. This method has the great advantage, that on each of the protruding serrations half of a stamping image additional space is provided for forming of complete articles, in the present case of a cover or bottom for cans or similar articles,whereby the length of the sheet corresponds to a whole number multiple of the width of the stamped image. In this manner no noteworthy waste will occur either on the ends or the sides in the case of succeeding-stamping, and the sheet material therefore is utilized as economically as possible. One will obtain more cut outs from a sheet of the same size by this scroll cut than with the use of the known processes.

It will be understood that the scroll cut can be used economically only when a guarantee for a great precision of the cut sheets exists. The precision of the sheets can be defined by four values: a

the length of the cut,

the width of the edge scroll,

the angularity of the sheet and as a consequence the parallelism of the scroll cuts.

A means for fulfillment for a part of the above mentioned values is the feed of the sheet. It consists generally of two phases, namely a coarse feed and a fine feed. Both movements are executed, generally speaking, with two rubberized feed rollers, whereby the pair of rollers for the fine feed lies directly in ,front of the fixed stops for the end of the sheet. After the sheet material, whose free edge already shows one scroll cut, has been moved by the coarse feed up to a certain distance in front of the solid stop, the edge of the sheet scroll is centered in two fixed stops during the subsequent fine feed. The lateral stops also serve as an auxiliary elements for the lateral guidance of the sheet.

Since the rolling mills will permit a certain, even though slight, lateral shifting of the coil within the framework of their permissible tolerances during production, the danger frequently exists that the scroll cut will shift and the precision of the sheet therefore has some uncertainties. This uncertainty can not be eliminated through the prescribed centering of the edge of the scroll sheet brought about by means of the feed alone.

SUMMARY OF THE INVENTION This is where the invention starts. It is the purpose of the invention with the inclusion of the means used for the feed to control the centering to such a point that it will guarantee with assurance the required high precision of the sheet with due consideration to the lateral shifting. According to the invention, this problem will be solved through the fact that the sheet is guided just to in front of the centering stop, in the case of coarse feed with simultaneous hunting transversely to its feed direction, with unilateral loose lateral guidance, then the hunting and lateral guidance of the coarse feed are nullified, and in the course of the subsequent fine feed the-front edge of the sheet is moved against the centering stop, with renewed hunting transversely to its feed direction, with unilateral loose and unilateral firm lateral loadof the sheet. These steps bring about an optimum accuracy of the sheet in the sense of the previously mentioned values with due consideration to the possible occurrence of lateral shifting of the coil during production.

Furthermore, the centering effect will be increased through the fact that, according to a further characteristic of the invention, the hunting of the sheet transversely to its feed direction takes place functionally independently of the feed.

The device to carry out the process in accordance with this invention includes a cutting unit having associated therewith a coarse and a fine feed, each including a pair of conveying rollers extending transversely to the running direction of the sheet and a pair of lateral load rollers arranged in the area of the conveying rollers, said rollers lying on both sides of the sheet and arranged behind the conveying rollers, and a fixed centering stop at the front edge of the sheet arranged in front of the fine feed. The previously mentioned feed action and simultaneous centering of the sheet material will be achieved according to the invention by the device through the fact that the conveying rollers of the coarse and the fine feed are shiftable in an axial direction, and that the guide rollers at the side of the sheet of the coarse feed are arranged one cuttinglength in front of the cutting unit and can be automatically moved from their sheet guiding position. At thesame time, the axial shiftability of the conveying rollers permits the hunting of the sheet transversely to its feed direction, so that both the movable lateral guide rollers as well as the fixed stop can correct the position of the sheet during feed in. The arrangement of the guide roller of the sides of the sheet of the coarse feed one cutting length in front of the cutting unit as well as the fact that they can be released automatically from their guide position will avoid a static find during the positioning of the sheet within the cutting unit.

It has been desirable for the effectiveness of the conveying rollers of the coarse feed to drive the coarse feed rollers in accordance with a further characteristic of the invention via an oscillating drive mechanism and an arrangement which will transform the feed and reverse stroke of an oscillating drive mechanism into a revolving movement and transfer it to the pair of rollers.

According to another characteristic of the invention, the fine feed is controlled via a radial curve and is applied through a pressure spring.

For a reliable releasing of the lateral load rollers from the side of the sheet during centering, the lateral load rollers of the coarse feed, according to a further characteristic of the invention, are connected with pistons guided hydraulically, pneumatically or in some similar manner in cylinders. This arrangement makes it possible, furthermore, in the case of other widths of sheets of the coils to adapt the lateral load rollers safely and precisely for guidance.

The invention will be explained in more detail on the basis of a design given by way of example, which is illustrated in the drawings.

FIG. 1 is a schematic side view of mechanism to carry out the process of this invention with particular emphasis on the feeding of the sheet.

FIG. 2 shows a schematic top view of the mechanism of FIG. 1.

FIG. 3 is a diagram of the course of movement for the sheet feed timing relative to the stroke of the cutting unit.

FIG. 4 is a diagram of the course of movement of the lateral load in relation to the stroke of the cutting unit.

In FIGS. 1 and 2 A designates the sheet portion of a coil, whose free end B has a scroll cut. The direction of movement of sheet A has been designated by arrow 1.

Viewed in the direction of arrow 1, in front of a conventional shear or cutter 2, there is the coarse feed mechanism generally designated by the reference numeral 3, and of a pair of conveying rollers 4 extending transversely to the direction of arrow 1 of the sheet A and lateral load rollers 5 lying on both sides of sheet A. While the distance of the conveying rollers 4 from cutter 2 has not been fixed exactly, but should lie as much as possible not too far away from said cutter, the position of the lateral load rollers 5 is definite. They are centered one cutting length in front of the tool of the cutter 2. The rollers 4 themselves, in order to achieve the optimum conveying characteristics, are provided effectively on their surface with at least a rubber coating, or else they consist entirely of rubber or some equivalent material. As becomes clear from FIG. 1, the driving and axial hunting of the lower roller 4, is accomplished in a conventional manner not shown such as via an oscillating drive and an arrangement transforming the feed and reverse movement of the pendulum drive into a rotational movement and transferring it to the pair of rollers 4.

The lateral load rollers 5 of the coarse feed 3, as shown in FIG. 2, are connected with pistons 8 guided pneumatically or some other way in the cylinders 7. While the left-hand rollers 5 positively engage the edge of the sheet, between the righthand rollers 5 and the piston 7 a spring 9 has been interposed, which permits a movability of the sheet A transversely to its feed direction 1. This movability will be encouraged further through the fact that the conveying rollers 4 are shiftable in an axial direction, as indicated by arrow 10.

There is also provided a fine feed mechanism which consists of the pair of conveying rollers 11 and lateral load rollers 12 which rollers 12 are arranged in the area of the cutter 2 or directly in front of it. As shown particularly in FIG. 2, the conveying rollers 11, which also are shiftable axially in the direction of arrow 10, have been arranged in the immediate vicinity of the centering stops 13 on the sides of the front edges in front of the end B of the sheet A. Of the lateral load rollers 12 of the fine feed mechanism, that pair of rollers 12 which lies to the left of the sheet A is fixed and that pair of rollers 12 which represents the right-hand guidance of the sheet A has been mounted for movement transversely of the sheet A. In the present case, a spring 14 has been interposed between a fixed support and the right-hand rollers 12.

The fine feed rollers 11 may be driven and axially hunted in any conventional manner including by way of a radial curve and applied by a pressure spring (not shown).

OPERATION The end B of the sheet A is moved up to about 25 mm in front of the centering stop 13 on the front edge side by the conveying rollers 4 of the coarse feed mechanism. At the same time, a pre-alignment will be achieved by means of the axial movability of the conveying rollers 4 with a simultaneous assistance of the loose right-hand lateral load rollers 5, 12 for the sheet A, by subjecting the end portion of the sheet A to a hunting movement transversely to the feed direction 1 through the lower conveying roller 4. After that, the hunting of the conveying rollers 4 is stopped the lower roller 4 is moved away from the sheet A in the direction of arrow 6 through the use of conventional mechanism (not shown). Simultaneously, all of the lateral load rollers 5 of the coarse feed mechanism 3 are retracted through action of the pistons 7 by means of pressure within the respective cylinder.

The end of the sheet is now thus influenced only by the conveying rollers 11 and the lateral load rollers 12 of the fine feed mechanism. The fine feed is accomplished in a conventional manner at a lower speed than the coarse feed and the free end B of sheet A is guided by said feed at a slow rate of movement toward the centering stops 13 on the front edge side. In the case of this slow rate of movement, a renewed hunting of the end of sheet A again takes place through the axially shiftable conveying rollers 11 and a simultaneous lateral alignment of the sheet through the lateral load rollers 12, the left end one of which is fixed and the right hand one is loose. Through the centering stop 13, on the one hand, and the lateral load rollers 12, on the other hand, the optimum positioning precision will be achieved in the case of this final stage of the feed, which now will permit the cutting of the cutter 2 without any hesitation. After the out has been made, the centering stops 13 are folded away downwards in the direction of the arrow in a conventional manner, the cut plate is carried away and the feed and centering process is repeated again by first of all the coarse feed starting up again in the previously described manner.

It is to be understood that the hunting of sheet A takes place transversely to its feed direction independently of the feed itself.

In FIG. 3 and 4 the course of the individual operating phases is shown in relation to the cutter stroke a in the manner of a diagram. For this purpose,the cutter stroke a has been subdivided into 360 in order to make the course of the movement more clear, although this is not to be interpreted that, in the case of the cutter 2, we are supposed to deal with a circular movement of the knife. The subdivision into 360 is merely to clarify the phase starting out from an initial position of the knife via the cutting process back into the starting position. It is clear that the actual cut takes place at about 180.

In FIG. 3, the following are presented in relation to the cutter stroke:

b the coarse feed 0 releasing of the coarse feed rollers 4 d the fine feed e the moving together of the fine feed rollers 11.

In FIG. 4 f designates the lateral guidance of the sheet by the coarse feed, and g the stop, in dependence on the cutter stroke a. The diagrams are self-explanatory so that no detailed explanations are required.

Although only a preferred embodiment of the invention has been specifically illustrated and described, it is to be understood that minor variations may be made in the construction of the various drive and guidance components without departing from the spirit and scope of the invention,as defined by the appended claims.

We claim:

1. A process for the feeding and simultaneous transversely centering of sheet material in a scroll cutting operation utilizing a fixed centering step to effect the precision cutting of scroll cut sheets for the further processing of the sheets into stamped parts, the process comprising the steps of advancing the sheet material in a coarse feeding operation relative to a cutter to a position wherein a leading edge of the sheet material is closely in front of the centering stop while simultaneously hunting the sheet material transversely of the direction of feed and applying a lateral guidance load to opposite side edges of the sheet material, discontinuing the coarse feeding operation and the associated guidance and hunting action on the sheet material, and then further advancing the sheet material in a fine feeding operation into engagement with the centering stop while simultaneously further hunting the sheet material transversely of the direction of feed and applying a second lateral guidance load to the opposite edges of the sheet material.

2. Process according to claim 1, characterized in that the hunting of the sheet material takes place transversely to its feed direction functionally independently of the feed.

3. The process of claim 1 wherein the transverse hunting of the sheet material is effected through the mechanism which effects the feeding of the sheet material and independently thereof.

4. The process of claim 1 wherein the edge guidance of the sheet material along one edge is positive and along the opposite edge the edge guidance is loosely resilient.

5. The process of claim 1 wherein the coarse feeding and guiding occurs in advance of the cutter and the fine feeding and guidance occurs beyond the cutter.

6. The process of claim 1 wherein the second lateral guidance load is applied to the sheet material during the later portion of the coarse feeding operation.

7. In a scroll cutting apparatus of the type including a scroll cutter and a centering stop for engaging a leading edge of sheet material, a combined feed and guide assembly comprising coarse feed means for simultaneously feeding sheet material past said cutter to a position wherein a leading edge of the sheet material is positioned closely adjacent said centering stop and hunting the sheet material transversely of the direction of sheet material feed, first guide means for engaging opposite edges of the sheet material and in cooperation with the hunting of the sheet material aiding in the centering thereof relative to said scroll cutter, and fine feed means operable independently of said coarse feed means for simultaneously further feeding the leading edge of the sheet material into engagement with the centering stop and hunting the sheet material transversely of the direction of sheet material feed, and second guide means for engaging opposite edges of the sheet material and in cooperation with the hunting of the sheet material by said fine feed means and the centering stop assuring centering of the sheet material relative to said scroll cutter.

8. The scroll cutting apparatus of claim 7 wherein each of said feed means includes a pair of feed rollers engageable with the opposite surfaces of sheet material, said feed rollers being axially movable to effect said sheet material hunting.

9. The scroll cutting apparatus of claim 8 wherein said feed means are disposed on opposite sides of said scroll cutter.

10. The scroll cutting apparatus of claim 7 wherein each of said guide means includes lateral guide rollers, means fixedly mounting guide rollers along one edge of the sheet material, and other means resiliently mounting guide rollers along the other edge of the sheet material.

11. The scroll cutting apparatus of claim 10 wherein the guide rollers of said first guide means are supported by movable supports operable to retract said first guide means out of engagement with the sheet material during the operation of said fine feed means.

12. The scroll cutting apparatus of claim 7 wherein said first guide means are spaced from said scroll cutter in advance thereof a distance equal to the spacing of said centering stop from said scroll cutter.