US3552176A

US3552176A - Device for rounding cutout pieces of very thin sheet metal

Info

Publication number: US3552176A
Application number: US666622A
Authority: US
Inventors: Walter Sommer
Original assignee: Fried Krupp AG
Current assignee: Fried Krupp AG
Priority date: 1966-09-10
Filing date: 1967-09-11
Publication date: 1971-01-05
Anticipated expiration: 1988-01-05

Abstract

A DEVICE FOR FOLDING THE END PORTION OF A METAL SHEET BY A RELATIVELY LARGE ANGLE, PREFERABLY AN ANGLE IN EXCESS OF 135*. THE DEVICE IS CHARACTERIZED PRIMARILY BY THE ARRANGEMENT OF A SINGLE FOLDING RAIL WHICH HAS A NOSE PORTION AND AN INCLINED SURFACE PORTION AND THE MOVEMENT OF WHICH IS SO CONTROLLED THAT FIRST THE SAID NOSE PORTIONS FOLDS THE RESPECTIVE METAL SHEET END PORTION BY 90* AND SUBSEQUENTLY THE SAID INCLINED SURFACE PORTION

FOLDS THE THUS FOLDED END PORTION BEYOND SAID 90* TO THE DESIRED TOTAL FOLDING ANGLE.

Description

W. SOMMER Jam s, 1971 DEVICE FOR ROUNDING CUTOUT PIECES OF VERY THIN SHEET MIE'IAL Filed Sept. 11, 1967 1/ m F w 5 Y u A Z B fl fl MM m. A

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United States Patent U.S. Cl. 72312 3 Claims ABSTRACT OF THE DISCLOSURE A device for folding the end portion of a metal sheet by a relatively large angle, preferably an angle in excess of 135. The device is characterized primarily by the arrangement of a single folding rail which has a nose portion and an inclined surface portion and the movement of which is so controlled that first the said nose portion folds the respective metal sheet end portion by 90 and subsequently the said inclined surface portion folds the thus folded end portion beyond said 90 to the desired total folding angle.

The present invention concerns a device for rounding, folding or bending the edges of pieces cutout of very thin sheet metal, by large angles, preferably by angles exceeding 135 by means of movable folding rails. By

means of devices of the just mentioned type, rectangularly shaped cutout fine sheet metal pieces which are to be processed to folded can bodies are rounded for preparing the fold on two oppositely located sides in oppositely pointing directions. Heretofore known devices of this type operate with folding rails which are movable in a single direction transverse or at an angle with regard to the plane of the cutout piece to be folded. However, with devices of the above-mentioned type it is possible within a single working operation to obtain a proper rounding, folding or bending only up to an angle of a maximum of 135 whereas for the rounding, folding or bending of larger angles, for instance the frequently desired angle. 'of' 150, two working operations are required. In this instance it is necessary by means of a first folding rail to fold about 90 whereupon the thus formed hook is to be folded further by a second folding rail by about 60".

It is an object of the present invention to provide a device of the above mentioned type which will overcome the above mentioned drawback.

It is another object of this invention to provide a device for rounding the edges of fine sheet metal pieces by any desired angle in a single working operation.

These and other objects and advantages of the invention will appear more clearly from the following specification in connection with the accompanying drawing, in which:

- FIGS. 1 and 2 respectively illustrate the device according to the present invention in two different positions, namely prior to the start of the rounding, folding or bending operation and after the rounding operation has been completed.

priority, application Germany, Sept. 10, 1966, I

FIG. 3 shows the folding rail in three different positions relative to the piece to be rounded, the scale of FIG. 3 being considerably larger than that of FIGS. 1 and 2.

The above outlined objects have been realized according to the present invention by the provision of a single folding rail which is so shaped and which is so moved that theportion of the piece to be folded is first bent by means of a nose by and is subsequently pressed against an inclined surface of the folding rail which inclined surface extends approximately in the direction of the desired deviation.

In the device according to the present invention, thus the folding rail is not moved in a single direction, i.e., rectilinearly, but is moved along a curve. According to a further development of the present invention, this curve is in the form of an approximately elliptically curved portion of a coupling curve which is produced by a fourbar linkage with oscillating driving crank.

The clamping device for the cutout piece to be folded is advantageously so designed that it is opened by the folding rail itself against a spring force as soon as the folding operation is completed.

Referring now to the drawing in detail, the arrangement shown therein comprises two

clamping rails

1 and 2 for clamping the cutout piece or metal sheet 3 therein. The said

rails

1 and 2 are connected to the housing 4 and cover 5. By means of dish springs 6 carried by the head of a threaded bolt 7 which can be raised and lowered by means of a nut 7a, the cover 5 and the housing 4 can be pressed against each other with the result that the two

clamping rails

2 and 1 are resiliently pressed against the piece 3.

Two

eccentric shafts

8 and 9 are arranged parallel to each other in the housing 4. The first eccentric shaft 8 is adapted to be turned back and forth by about 90 by means of a drive comprising a connecting rod 10, a rack 11 and a gear 12. Mounted on the respective eccentricesin FIGS. 1 and 2 indicated by their

centers

13 and 14 and the centers 13, 14' of the

shafts

8, 9, respectively-is a link member 15 which is diagrammatically illustrated in FIGS 1a and 2a of the drawing, corresponding to the FIGS. 1 and 2, respectively. Connected to said link member is a folding rail 15a. This folding rail 15a has a surface 16 extending transverse to the plane of the piece 3 to be rounded. The said surface 16 serves in its starting position (FIG. 1) as abutment for the edge of the piece to be rounded and merges through a nose 17 with an inclined surface 18. By means of an adjacent further surface 19, the rail 15a will in the starting position of FIG. 1 lift an abutment screw 20 screwed into the cover 5 and will thus also lift the cover 5 with the clamping rail 2 so that it is possible to introduce a new cutout piece. The movement of the rail 15a which is required for folding the piece 3 is effected by means of the rocker mechanism which consists of

shafts

8 and 9, the

eccentrics

13 and 14 pertaining thereto and the link member 15 mounted on said eccentrics. This folding operation is produced by the fact that in view of the upward movement of the connecting rod 10, the shaft 8 is turned from its starting position shown in FIG. 1 in which the center 13 of the respective eccentric is located on the right-hand side of and adjacent to the pivot axis of shaft 8 in clockwise direction by 90 until it has reached its position shown in FIG. 2. The nose 17 of the folding rail which, as is evident from FIGS. 1 and 2, is located approximately on the extension of the connnecting line between

points

13 and 14, moves along an elliptical curve section of a so-called coupling curve which elliptical curve section is shown in FIG. 3 on a larger scale and is designated with the reference numeral 21. With this movement, as will be evident from FIG. 3, the free end of the cutout piece or metal sheet 3 is first bent downwardly and subsequently is pulled over the back of the nose 17 until eventually it has assumed the direction of the adjacent inclined surface 18. Thereupon, the rail 15a moves back on the same path and after having reached the starting position shown in FIG. 1 lifts the cover 5 with the clamping rail 2 again so that the folded metal sheet 3 in its direction perpendicular to the drawing plane can be removed and can be replaced by a new one.

It is, of course, to be understood that the present invention is, by no means, limited to the particular construction shown in the drawing but also comprises any modifications within the scope of the invention.

I claim:

1. A device for folding the end portion of a metal sheet at an angle greater than 90, comprising a frame, two clamping rail means mounted on said frame and having opposed clamping surfaces for clamping a metal sheet therebetween, said clamping rail means being movable toward each other into clamping position and away from each other into releasing position for clamping and releasing a metal sheet between said surfaces, at least one of said clamping rail means having an edge extending from its clamping surface forming an angle with said clamping surface greater than 90 and at least as great as the angle to which the end of the metal sheet is to be folded, a folding rail arranged opposite said clamping rail means and comprising a nose portion projecting toward said clamping rail means and an adjacent inclined portion, and control means including a link member fixed to said folding rail forming one element of a four-bar linkage, and two eccentrics on which said link member is mounted, said two eccentrics being rotatably mounted on said frame and forming two elements of said four-bar linkage, and means to operate said eccentrics to cause said folding rail to move transversely of said clamping surfaces and a sheet metal end held therebetween to bend said sheet metal end transversely, said eccentrics further moving said folding rail toward said clamping rail means to engage said sheet metal end with said inclined surface to fold said sheet metal end over said edge of one of said clamping rail means, thereby forming an angle substantially the same as the angle of the edge of said rail means.

2. A device in combination according to claim 1, in which said control means is operable to move said folding rail over an elliptically curved portion of a coupling curve.

3. A device in combination according to claim 1, which includes additional means operatively connected to one of said clamping rail means and operable by said folding rail at the end of each folding cycle for automatically moving said clamping rail means relative to each other resiliently into said releasing position.

References Cited UNITED STATES PATENTS 1,055,973 3/1913 Graham ll3ll 2,569,181 9/1951 Laxo 72-312 3,058,512 10/1962 Chebuhar et a1. 72305 LOWELL A. LARSON, Primary Examiner U.S.Cl. X.R. 723 19