US3550931A

US3550931A - Apparatus for folding flexible materials

Info

Publication number: US3550931A
Application number: US797771A
Authority: US
Inventors: Kurt Hoffmann
Original assignee: CHROBOK HOFFMANN KG
Current assignee: CHROBOK HOFFMANN KG
Priority date: 1968-02-26
Filing date: 1969-02-10
Publication date: 1970-12-29
Anticipated expiration: 1987-12-29
Also published as: FR2002615A1

Description

United States Patent Inventor App]. No.

Filed Patented Assignee Priority Kurt Hoffmann Heidelberg, Germany Feb. 10, 1969 Dec. 29, 1970 Chrobok-Hoffmann K. G.

Eppelheim, near Heidelberg, Germany Feb. 26, 1968 Germany APPARATUS FOR FOLDING FLEXIBLE MATERIALS 9 Claims, 7 Drawing Figs.

[52] US. Cl 270/61 [51] Int. Cl B65h 45/00 [50] Field of Search 270/61 [56] References Cited UNITED STATES PATENTS 3,024,019 3/1962 Ladenburger 270/61 3,148,874 9/1964 Forthmann, Jr 270/61 Primary Examiner-Eugene R. Capozio Assistant Examiner-Paul V. Williams AtzorneysFrancis D. Stephens and Hugo Huettig, Jr.

ABSTRACT: Pairs of vertically movable flat plates having die openings are used to fold the edges of flexible materials.

upper portion containing a press plate, a press plunger, and

means for folding the material and ejection of the finished piece. This invention simplifies the construction and considerably improves the operation of the plural operational steps of heretofore usedfolding apparatus. In the heretofore used folding apparatuses which fold in oneoperational cycle and upon which -this invention is an improvement, the two spaced plates which form the lower portion of the apparatus are rigidly connected to each other while the press plate can be moved vertically through a die opening in the upper plate of the lower tool portion. The upper portion also is composed of two spaced plates which are rigidly connected to each other. The plunger. below the lower plate of the upper portion, is rigidly connected to the folding knife forming the outer edge. A plate joined to the plunger can be moved vertically for pressing down on and holding the workpiece in place. The folding step takes'place during the lowering of the plunger in the lower portion of the apparatus and at the same time the plunger, during itsupward return movement to its original position, and by lifting the upper portion ejects the finished workpiece. Since this apparatusoperates with a special apparatus for holding the workpiece in place and with a folding knife which surrounds the clamping apparatus, it is possible to fold only workpieces up to a certain size. The use of a folding knife can cause disruptions, especially when glue is used.

The object of this invention is to reduce substantially the cost of the folding apparatus and simultaneously to improve upon its operation by making it adaptable to multiple use for all usual and conventional workpiece sizes.

In general, this object is obtained in this invention in that the press plate is rigidly connected with the lower plate of the lower portionof the apparatus and can bemoved through a die opening having a recessed rim formed in the upper plate which is moved relative to the lower plate against spring pressure. The press plunger is rigidly connected to the plunger holding plate which is positioned so that it can be moved vertically between the lower and upper plates of the upper portion which are rigidly connected to each other, and with the plunger holding plate being urged to is upper position by springs. and with the use of clamping means that can be released in the lower position by the plunger holding plate so that the pressplunger can slide through the die opening in the lower plate of the upper portion. Consequently, in this invention, the press plate, in contrast to the heretofore used apparatus, is rigidly joined to the lower portion of the apparatus, and in which the upperplate of the lower portion is movable. The press plunger within the upper portion of the apparatus is also movable, as contrasted to the press plunger rigidly connected in the upper portion of the heretofore used apparatus.

As contrasted to the heretofore used apparatus, this invention results. in a simplified construction and an improved operating technique. This invention does not require a special folding knife as heretofore used. In this invention, there is instead attached to the lower side of the lower plate of the upper portion a folding plate which fits into a recessed rim in the upper plate of the lower portion. The folding step is improved in that the inner side edges of the folding plate extend in a curve to its bottom and to the lower surface of the completely retracted plunger. This arrangement makes it possible to size the press plate as well as thepress plunger and folding plate as small as possible and to use them for small workpieces often encountered in this work. Also, the elimination of the folding 75 knife avoids any disruption of the apparatus.

In this invention, posts, pins or pegs are attached to the lower plate of the lower portion which are slidable-in bores of the upper plate and whose upper ends are conical and extend beyond the upper plate through bores through the lower plate .of the upper portion and act in conjunction with the releasable clamping and fixing device of the upper portion of the apparatus. This control clamping device. for the plunger holding plate has a further feature in that two. sliders are arranged on" the narrow sides of the upper portion and which are slidable in guide members which are fixed to the lower plate of the upper portion. The head of each slider facing the plunger holding plate has a nose which can extend over the plunger holding plate. Each slider is held in its clamping position by a pressure spring. Also, the head of each slider is beveled forming a surface which the plunger holding plate engages during its downward movement so that the sliders are pushed outwardly. Bores extend through the sliders and guide members through which the conical ends of the guide posts of the lower portion can extend and engage and force the sliders into their release positions so that the plunger holding plate can be released. Finally, the sliders are provided with a stop on their outer ends which restrict their engaged position.

The surface of the press plate can be provided with the conventional stampings for ornamenting the surface and serrating the edges of the workpiece. By means of this, it is possible that very small workpieces can be provided with fluted or serrated edges.

The means by which the objects of this invention are obtained are described more fully with reference to the accompanying drawings in which: 7

FIG. I is a longitudinal cross-sectional view through the apparatus as taken on line H of FIG. 2 and in which the left side of the FIG. shows the apparatus in open position and the right side in closed position; v

FIG. 2 is a cross-sectional view along-the line ll-II in FIG. 1;

FIG. 3 is a cross-sectional view taken on the line Ill-III of FIG. 1;

FIG. 4 is a schematic plan view of the various steps taken in the folding of the edges of a workpiece;

FIG. 5 is a cross-sectional view taken on the line V-V of FIG. 4; g

FIG. 6 is a similar view of the intermediate step with the edges standing vertically; and

FIG. 7 is a cross-sectional view taken on the line VII-VII of FIG. 4.

The folding apparatus of this invention has two main portions, namely, the lower portion and the'upper portion.

' The lower portion is composed of a basev plate 1 on which the guide posts 2 and 3 for the guideplate 4 are fixedly mounted. Guide posts 2 are positioned approximately at the four outer corners of plates 1 and 4 and are at the same time used as the bearing members for compression springs 5. The

posts 2 are made as threaded bolts for the purpose of holding. springs 5 on the underside of guide plate 4 and are inserted through the springs and screwed into the base plate 1. Guide posts 3 extend upwardly and somewhat beyond the upper guide plate 4. The posts have conical upper ends 6. Threaded holes 7 are positioned on the outer corners of plate 1 for attaching this plate to a machine table. However, a dovetail joint can be used for attaching plate 1 instead of using threaded holes 7. Fixed to the center of the upper surface of plate 1 is a press plate 8 whose surface corresponds to the'shape of the workpiece that is to be folded. A die opening 9 is in the upper guide plate 4 and into which plate 8 extends when plate 4 is moved against the pressure of springs 5 toward plate 1. A recessed rim 10 which is larger than the size of opening 9 is used for placing the workpiece to be folded.

The upper portion of the apparatus is composed of two plates which are the lower plate 11 and the upper plate 12 fixed to each other by four bolts 13 positioned at the corners of plates 11 and 12. Folding plate 144 is, fastened to the lower side of lower plate 11 and plate 14has a sliding, fit into the recessed rim, 10 in the guide plate 4 in the lower portion.

Plunger holding plate 15 which is movable up and down is positioned between the two plates 11 and 12 in the upper portion imam is'guided in the upper plate 12 by means of posts 16. Two'posts a'reshown in the drawing. Compression springs 17 ,are positioned'on the four corners of the plunger holding plate 15 which urge plate '15 upwardly against upper plate 12. F Plunger 18 is fastenedto the lower side of plunger holding plate 15 and is moved up'and down along with plunger holding plate 15 and is slidably guidedthrough an opening 19 in lower plate 11. Plunger 18 can be made in one piece. However, for special production techniques, its lower part 20 can be made of a special piece which is attached to the lower surface of the actual plunger 18. In order to hold plunger holding plate 15 in its lower position against the pull of spring 17, a releasable clamping device is positioned on each outer side, respectively, on the upper surfaces of plate 11 and between plates 11 and 12 and also opposite guide posts 16. In plane view, these clamping devices are on the narrow sides of the rectangular outline of the machine. These clamping devices hold plunger holding plate 15 in its lower position. Each of these clamping devices is composed of a slider 21 which can be reciprocated toward and away from holding plate 15 and which slider is held in a guide member 22 fixed to plate 11. The end of slider 21 facing plunger plate 15 has a head 23. This head has a nose 24 which extends over the edge of plate 15 when the plate is lowered and which holds the plate 15 down against the pull of spring 17. The slider is held in clamping position by a spring 25 which bears against guide member 22 and head 23 and urges the head toward plunger holding plate 15. A stop pin 26 is inserted through the outer end of slider 21 for restricting the forward movement of slider 21'.

In the right-half side of FIG. 1 and in FIG. 2, the plunger holding plate 15 is shown in its lowered position in which it is held by the nose 24 on slider 21. The left-half side of FIG. 1 shows'the holding plate in its released upper position in which it is forced upwardly by springs 17 into contact with upper plate 12.

Bores

27 and 28 in slider 21 and guide member 22, respectively, are entered by the conical ends 6 of guide posts 3 when the upper portion of the apparatus is moved toward the lower portion. The guide posts 3 are then extended through

bores

27 and 28 so that their conical ends 6 engage and push r the sliders outwardly whereby the noses 24 are released from the plunger holding plate 15 which is then quickly moved upwardly by springs 17. Post 29 attached to the upper side of plate 12 in the upper portion is used to hold the upper portion in the apparatus.

In operation, the blank workpiece, as, for example, a stamped out piece of leather, such as shown in FIG. 5, is placed with its front side downwardly in the open machine, as in the left side of FIG. 1, and in the recessed rim of guide plate 4. Then the upper portion of the tool is lowered and guided by posts 3 toward guide plate 4. This brings the plunger 18. 20 into contact with the workpiece and presses the same into the die opening 9. When the

plunger

18, 20 enters the die opening 9, the edges of the workpiece are turned up all around the workpiece, as shown in FIG. 6. In the'lowermost position of the

plunger

18, 20 in which the workpiece has reached the bottom of die opening 9 and when

plunger

18, 20 is directly on top of the workpiece, as shown in the right half of FIG. I, the conical ends 6 of posts 3 release the control clamping device 21 which lies between plates 11 and 12 of the upper portion. Because'of the pressure of springs 17, the plunger holding plate moves rapidly upward until it reaches a stop on the underside ofupper plate 12. In this manner, the plunger 18, is pulled out of die opening 9. This is the position as shown in the left side of FIG. 1. At this time, the workpiece is still on the bottom of die opening 9 with the folded edges extending vertically at right angles. as shown in FIG. 6. The entire upper portion of the tool is moved at this point further downwardly by motor means. not shown. whereby the folding plate 14 enters the recessed rim l0 and bears on the bottom of the rim. The upper portion is lowered further and pushes guide plate 4 downwardly against the pressure of springs 5. During this time. plate 4 pushes downwardly around press plate 8 which enters die opening 9 so that the workpiece enters the interior of the folding plate 14. During this step. the upright edgesof the workpiece enter guide plate 4 which has a curved corner between its inner .side edges and the bottom .of the fully retracted

plunger

18, 20 so that the upstandingedges. are completely folded over and pressed tight; as shown in FIG.. '7 and in the right side of FIG..,4.. Since the edges of the work;

piece have been coated with glue before the workpiece was placed in the apparatus, these edges become tightly glued during the last pressing of the workpiece. When the workpiece edges are to be serrated, then the surfaceof the press plate 8 has to be provided with a corresponding profile aside from its outer edges. This makes it possible to fold and serrate the edges of the workpiece in one work step. After folding and, if desired, simultaneously serrating the edges of the workpiece, the workpiece lies within the folding plate 14. Then the workpiece is carried along during a further lifting of the upper portion until the upper ends of the guide posts 16 joined to plunger holding plate 15 come into contact with a stop, not shown, in the apparatus. Then the plunger holding plate 15 is pressed downwardly against the pressure of springs 17 during a further lifting of the upper portion. During this motion, the outer edges of plunger holding plate 15 engage the beveled surfaces 30 above the noses 24 on the sliders 21 and thus force the sliders outwardly during a further movement until the plunger holding plate 15 comes into contact with the upper surface of lower plate 11 of the upper portion and the noses 24, because of springs 25, clamp over the edges of the plunger holding plate 15. The

plunger

18, 20, while this movement is taking place, comes out of folding plate 14 whereby the folded and finished workpiece is ejected downwardly.

I claim:

1. An apparatus for folding flexible materials such as leather, textiles and corresponding synthetic materials comprising a lower portion having a lower plate I spaced from an upper plate 4 having a die opening 9 therein surrounded by a recessed rim 10, a press plate 8 mounted on said lower plate 1 and movable through said die opening 9, spring means 5 for movably supporting said upper plate 4; an upper portion having a lower plate 11 and an upper plate 12, a plunger holding plate 15 vertically movable between the lower plate 11 and the upper plate 12, spring means 17 for urging said holding plate 15 toward said upper plate 12, clamping means 21 for clamping said holding plate 15 on said lower plate 11, and a press plunger 18 secured to said holding plate 15 and movable by said holding plate 15 through said die opening 19 in said lower plate 11.

2. An apparatus as in claim 1, further comprising a folding plate 14 secured to the underside of said lower plate 11 and surrounding said press plunger 18 and fittable in said recessed rim 10.

3. An apparatus as in claim 2, said folding plate having a curved inner side edge extending from the lower face of said folding plate to the lower face of the press plunger 18 when in fully retracted position.

4. An apparatus as in claim 3, further comprising posts 3 joined to said lower plate 1 and extending through bores in said upper plate 4 and said lower plate 11, and conical end means 6 on said posts for actuating said clamping means 21.

5. An apparatus as in claim 4, saidclamping means 21 comprising a guide piece 22 secured to said lower plate 11, a slide movable through said guide piece;a head 23 on said slide and nose means 24 on said head for releasably clamping said plunger holding plate 15 to said lower plate 11.

6. An apparatus as in claim 5, further comprising spring means 25 between said guide piece 22 and said slide for urging said slide to clamping position on said plunger holding plate.

7. An apparatus as in claim6, further comprising diagonally slanted surface means 30 on said head 23 engageable by said plunger holding plate 15 for releasing said slide from said clamping position during downward movement of said plunger holding plate.

9. An apparatus as in claim 8, funther comprising fluted surface means on said press plate 8 for folding the serrated edge of a workpiece.