US2703143A - Free floating punch holder mechanism - Google Patents

Description

March 1, 1955 Q GQQD ET AL 2,703,143-

FREE FLOATING PUNCH HOLDER MECHANISM Filed April 3, 1952 Sheets-Sheet l u i I' U i I I I j; 5 i f;

i I I I zo r I I :----20 3 59; I i 22 22 k 612% 62 \l" l I $0 INVENTORS CHARLES E. G000 3 Lou/s 5. JENNINGS A TTORNE )4 March 1, 1955 g, GOOD ETAL 2,703,143

FREE FLOATING PUNCH HOLDER MECHANISM Filed April 5, 1952 2 Sheets-Sheet 2 I E /O /0 4 r/O f f 62 r 28 /8 26 22 ---/O l 68 64 22-a9 si 36 4 w .1nnnnnrl: 54 g u;

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L i /e 44 INVENTORS CHARLES E. 6000 c2 Laws ,5. JENNINGS ATTOPNEY.

United States Patent FREE FLOATING PUNCH HOLDER MECHANISM Charles R. Good, Detroit, and Louis E. Jennings, Farmington, Mich., assignors to Copco Steel and Engineering Company, Detroit, Mich., a corporation of Michigan Application April 3, 1952, Serial No. 280,304

Claims. (Cl. 164-124) This invention relates to a novel and inventive tooling set for use on press brake machines, or similar equipment, to punch or perforate metal sections of flat or formed metal stock.

The improvement in punch tooling embodied in this invention achieves such objects as simplicity, flexibility, lower tool costs, easier tool set-ups and repairs, faster tool set-up time, and generally a great increase in tool and machine efliciency.

These objects of the invention are obtained by the use of complementary rails holding the punch mechanism in positive and full free floating engagement, a dye block to guide and control the punch holder, and a positive stripper action in the die block.

Instead of using stripper springs on the punch holder mechanism, a positive stripper action is combined with a full floating punch to make every ram stroke positive in effect. Tool breakage is practically eliminated, and tool wear held to a minimum by the tooling construction here disclosed. In addition, the losses due to stripper spring failures are eliminated. Additional objects of the invention will appear in the more detailed description given below.

The description together with the appended drawings is a disclosure of forms which the invention may take, and is not in any way intended to be a limitation of the forms or variations which persons skilled in the art may make. The terms are used for purposes of description and not of limitation.

Referring now to the drawings annexed hereto and forming an integral part of this specification,

Fig. 1 is a side elevation partially in section of one form of the invention.

Fig. 2 is a front elevation of the tooling shown in Fig. 1.

Fig. 3 is a sectional view on the line 33 of Fig. 1.

Fig. 4 is a sectional view on the line 4-4 of Fig. 1.

Fig. 5 is a sectional View on the line 55 of Fig. 1.

Fig. 6 is a front elevation of a series of tooling embodying the invention and assembled in a single press brake.

Fig. 7 is a fragmentary sectional view similar to Fig. 1, showing the positive stripper action of the cooperating elements.

Fig. 8 is a side elevation partly in section similar to Fig. 1, for flat stock.

The press brake tooling embodying the invention comprises three principal elements, namely the ram rails 10, the punch holder 12 and the die block 14. Together with a base support 16, the entire tooling mechanism cooperates and coacts to punch and perforate metal sections in a novel and inventive manner.

A press brake ram 18, designed to reciprocate upwardly and downwardly in a pair of parallel ram guides (not shown), is the supporting member for a pair of horizontally positioned, parallel, opposedly mounted ram rails 10. Each rail 10 is designed to be held by mounting bolts 20, passed through the body portion 21, that lock the rail vertically to the bottom of the ram 18. On the sides of rails 10 that face each other, an inwardly projecting ledge or shoulder 22 provides a guide space, among other functions, for the location of punch holders 12. The ledge 22 extends the length of the rail 10.

The punch holder 12 is made of round tool stock and has a flange portion 24 at one end of larger diameter than the body portion 26. The diameter of flange 24 is less than the distance between the rail body portions 21;

2,703,143 Patented Mar. 1, 1955 this difierence may allow as much as on each side of the flange diameter for free floating movement between the rails. A pair of parallel flats 28 are cut on the flange 24; the distance across the flats being less than the open distance between the rail ledges 22 facing each other. The main body portion 26 of the punch holder 12 is round, but the lowermost section of the holder has a flat portion 30 cut lengthwise the punch holder body, the function of which will be described below. In the center of the punch holder 12 at the end, opposite flange 24 is a punch opening 32 adapted to receive and hold a punch tool 34 of the desired form and length. The usual method and means of retaining such a tool 34 is to cut angled flats 36 on the tool shank, drill and tap set screw holes in the punch holder body 26 perpendicular to the flats 36 on the tool shank, and insert set screws 38 to retain the punch tool 34 in the holder body 26. A rod passage 39, for removing tight punch tools 34, is located above the tool punch opening 32 extending through the holder body 26.

The die block 14 is designed to rest upon and be anchored to the base support 16. A die block retaining screw 40 is passed through the die block body 42 and into the base support 16. A locating pin 44 in the base support 16 positions the die block body 42 in proper alignment for operation.

A work slot 46 is cut into the die block body 42. The work slot 46 of Fig. 1 is arranged for T-section work material; the work slot 47 of Fig. 8 is designed for flat work material. In Fig. 8, a screw stop 48 locates the flat work for punching or perforation. In Fig. l, the shoulders 50 of the die block body 42 locate the T- section flange of the work. A clamping finger 52, shown in broken lines in Fig. 1, is actuated to retain the T-section work in work slot 46 during the punching cycle. The various mechanical or hydraulic means to hold the T-section work in proper position are well known in the art to which this invention pertains, but such means does not form an element of this invention.

The die block body 42 also contains a die 54 which is positioned in the body 42 in proper relation to the punch tool 34. The die 54 lies below the work slot 46, and has a pair of angled flats 56 cut in its side. A pair of drilled and tapped holes in the die block body 42, for die retaining set screws 58, lie perpendicular to the angled flats 56 on the die. An exit opening 60 for punchings lies below the die 56 in the body 42.

Above the work slot 46, a punch holder guide hole 62, usually having a vertical axis common with that of the die 54, is located in the upper portion of the die block body 42, as distinguished from the portion below the work slot 46.

At the top of the die block body 42, and bordering on the guide hole 62 is guide block 64, having a flat edge 66 complementary to the punch holder flat 30. A set screw 68 holds the guide block 64 in place in its seat 70, cut out of the body 42.

The punch tool 34 can be designed with a round shank portion for insertion in the punch opening 32, the working end of the tool having any desired shape and length. In Figs. 1 and 5, a square end tool is shown; in Fig. 8, a round end tool is shown.

In operation, the ram rails 10 are mounted on ram 18, in parallel, with ledges 22 facing each other. The punch holder 12, with tool 34 locked in place, is passed between the ledges 22 of rails 10. A quarter-turn places the flange 24 across the rail ledges 22.

The die block body 42 is mounted on base support 16 by retaining screw 40, the locating pin 44 fitting into the appropriate opening in the base of the die block body 42. Die 54 is locked in place in the body 42, and the punch tool 34 is lined up with it; the tool set and the base support 16 are then placed on and clamped to the press brake die table.

At the beginning of the punching or perforating cycle, the press ram 18 is at rest at the top of its stroke. The free floating punch holder flange 24 rests upon the rail ledges 22, as in Fig. 7. The work is placed in the work slot 46, and the press ram actuated. When the punch tool 34, on the downward stroke of the ram 18, meets 1 the work, the punch holder flange 24 begins to pass upwardly between the rails until the ram 18 meets the top of the punch holder 12. Continuing downward the ram 18 forces the punch tool 34 into and through the work, the punching dropping into exit opening 60.

As the ram begins its upward stroke, the punch holder 12 is at rest, with tool 3 in the work. This state con tinues until the rail ledges 22 meet the underside of punch holder flange 24, as in Fig. 7. Then the upward force of the ram 18 pulls the punch holder 12 upwardly. The tool 34 carries the work upward to the top of the work slot 46, whereupon stripper action occurs, and the work is positively stripped of the tool 34.

The punch holder flat 3t rides against and is guided by the flat edge 66 of guide block 64, in the die block; body 42, during the downward and upward strokes. Guide block 64 prevents rotation of the punch holder 12 during the punching cycle, a factor that is of great importance not only to tool life and wear but also to keeping the punch holder flange 24 in proper relation to rail ledges 22. A further important function of punch holder body flat 30 and guide block edge 66 is that punch forms other than round can be used without the danger of rotation of the punch holder. Square, oval and irregular forms on punches are positive in relation to their dies at all times.

The tool set of this invention is excellently adaptable to form and stamp metal, as well as punch and perforate, simply by changing the punch and die elements, and 54 respectively.

When it is desired to remove the punch holder 12 from the rails 10, for repair or replacement, the press ram 18 should be moved to the top of its upward stroke. The punch holder 12 will then have its flange 24 resting upon the ledges 22, and the holder 12 can be gripped by the hand and lifted upward until the body flat 30 is out of and above the guide block 64. A quarter-turn (90) will place the punch holder flange flats 28 parallel to the rail ledges 22. By tilting the flange 24 downwardly, it will pass between rail ledges 22 and out into the open. In this way, tool sets can be placed fairly close together; in some cases even side by side, because the tool punch holders 12 can be tilted either way. Another advantage of this construction is that it is not necessary to pass the punch holders 12 to the ends of the rails 10 to remove them from the machine. When the press ram is at the top of its stroke, there is suflicient open space between the ram rail bottom and the top of the die block lg! to allow removal of the punch holder 12 from between t cm.

Our invention is described in its simplest terms, but details may be varied in greater or lesser degree without departing from the essence of our invention.

We claim:

1. A press brake punch tool set for a vertically reciprocatingly movable ram comprising a pair of rails fixedly mounted in depending position on the bottom of said ram and spaced apart from each other in parallel relation, each rail having an inwardly facing projecting ledge at its lower inner edge; a punch holder having an outer flange at one end engageable by said rail ledges, said flange having flats thereon with a diameter less than the distance between said rail ledges, said flange having a maximum diameter larger than the distance between said rail ledges but less than the open distance between said rails, said punch holder having a body whose maximum diameter is less than the distance between said rail ledges so as to allow said punch holder to be turned 90 about its longitudinal axis when being removed from said ram, punch holding means, and a guide fiat on the outer surface of its body; a die block adapted to locate on the die table of said press brake, said die block having a die and a work slot above said die, a punch holder guide hole in said die block and a guide block at said punch holder guide hole complementary to said punch holder guide flat preventing rotation of said punch holder when said punch holder body is in said punch holder guide hole; said ram rails having an inside free height above said rail ledges sulficient for vertical free travel of said punch holder and punch out of said die block when said ram is at the top of its stroke.

2. A press brake tool set for a vertically reciprocatingly movable ram for punching or perforating metal sections comprising a pair of press brake ram depending rails arranged in parallel relation, fixedly mounted on the bottom of said ram and spaced apart from each other, each of said rails having a projecting ledge at its lowermost inner corner, said ram rail ledges being spaced apart from each other, a punch holder engageable upon said ram rail ledges having a punch tool at one end and a partial peripheral flange at the other end, said flange being engageable by said ram rail ledges upon upward movement of said ram, said flange having flats thereon with a diameter less than the distance between said rail ledges and a maximum diameter larger than the distance between said rail ledges, said punch holder having a body portion whose maximum diameter is less than the distance between said rail ledges so as to allow said punch holder to be turned about its longitudinal axis when being removed from said ram, said punch holder being actuated by said ram upon its downward movement, said punch holder being free floating within said ram rails, a die block cooperative with said punch holder and said punch tool located upon the die table of said press brake, said die block having a punch holder guide passage and a guide block at said guide passage complementary to said punch holder and preventing rotation of said punch holder when said punch holder is in said guide passage, said ram rails having an inside free height above said rail ledges suflicient for vertical free travel of said punch holder and punch tool out of said die block when said ram is at the top of its stroke.

3. A press brake tool set for a vertically reciprocatingly movable ram for punching or perforating metal sections comprising a pair of press brake ram rails fixedly mounted On and arranged in parallel depending relation from said ram and spaced apart from each other, each of said ram rails having a ledge projecting toward each other at the lowermost inner corner of said ram rail, a punch holder having a partial peripheral flange at one end engageable by said ram rail ledges, said punch holder flange being free floating between said ram rail ledges, said flange having flats thereon with a diameter less than the distance between said rail ledges and a maximum diameter larger than the distance between said rail ledges, said punch holder having a body portion whose maximum diameter is less than the distance between said rail ledges so as to allow said punch holder to be turned 90 about its longitudinal axis when being removed from said ram, a die holding and punch holder guiding means cooperative with said punch holder, said means having a guide block complementary to said punch holder and preventing rotation of said punch holder, said punch holder being removably insertable in said means, said ram rails having an inside free height above said rail ledges suflicient for vertical free travel of said punch holder out of said die holding and punch holder guiding means when said ram is at the top of its stroke.

4. A metal forming tool set for use with a press having a vertically reciproeatingly movable ram comprising a pair of ram attachable rails spaced apart from each other in parallel relation, fixedly mounted on and depending from said ram, each of said rails having an inwardly facing ledge at its lower inner corner, a free floating punch holder having a flange engageable by and between said ram rail ledges, said punch holder having portions of its flange removed to allow ingress to and egress from said ram rails for engagement with and disengagement from said inwardly facing ram rail ledges, said flange having flats thereon with a diameter less than the distance between said rail ledges and a maximum diameter larger than the distance between said rail ledges, said punch holder having a body portion whose maximum diameter is less than the distance between said rail ledges so as to allow said punch holder to be turned 90 about its longitudinal axis when being removed from said ram, a die block cooperatively arranged with said punch holder having a mating die, and a punch holder guide block in said die block preventing rotation of said punch holder flange out of engagement with said ram rail ledges when said punch holder is cooperatively mated in said die block, said punch holder having a body portion flat thereon complementary with said guide block, said ram rails having an inside free height above said rail ledges suflicient for vertical free travel of said punch holder out of said die block when said ram is at the top of its stroke.

5. A metal forming tool set for use with a press having a vertically reciprocatingly movable ram comprising a pair of ram attachable rails spaced apart from each other in parallel relation, fixedly mounted on and depending from said ram, each of said ram rails having a ledge projecting toward the other at the lowermost inner corner of said ram rail and a supporting body portion eontiguous to said ram, a free floating punch holder having a flange at its upper head and a metal forming punch tool at its lower end, said punch holder flange having a maximum diameter larger than the distance between said ram rail ledges, said punch holder flange having flat portions thereon, the diameter across said flat portions being less than the distance between said ram rail ledges, said punch holder having a body portion whose maximum diameter is less than the distance between said ram rail ledges so as to allow said punch holder to be turned 90 on its longitudinal axis when being removed from said ram, a die block cooperatively arranged with said punch holder having a mating die, and a punch holder guide in said die block preventing rotation of said punch holder flange out of engagement with said ram rail ledges when said punch holder is cooperatively mated in said die block, said punch holder having a body portion flat thereon complementary with said guide, said ram rails having an inside tree height above said rail ledges UNITED STATES PATENTS 2,715 Fowler July 11, 1842 471,084 Hopkin Mar. 15, 1892 824,044 Southworth June 19, 1906 1,052,527 Stimpson Feb. 11, 1913 1,319,411 Nelson Oct. 21, 1919 1,661,188 Matthews Mar. 6, 1928 1,925,034 Fitzgerald Aug. 29, 1933 2,601,108 Emmer June 17, 1952

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