US2586536A - Pressure fluid clamp - Google Patents

Description

Feb. 19, 1952 HALLER PRESSURE FLUID CLAMP 2 SHEETS- SHEET 1 Filed Aug. 17, 1948 @MM #wwf/Lee Gttorrw's Feb. 19, 1952 J. HALLER PRESSURE FLUID CLAMP 2 SHEETS-SHEET 2 Filed Aug. 17, 1948 .www

Gttornegs Patented Feb. 19, 1952 PRESSURE FLUID CLAMP John Haller, Detroit, Mich.

Original application March 15, 1947, Serial No. 734,904, now Patent No. 2,467,740, dated April 19, 1949. Divided and this application August 17, 1948, Serial No. 44,622

3 Claims. 1

This invention relates to feeding mechanisms and in particular to clamping devices for auto-V clamping device for clamping sheet material to a support, the device being hydraulically actuated to press a clamping member into engagement with the sheet material so as to hold it firmly against the support so long as the device is supplied with pressure fluid.

Another object is to provide a clamping device as set forth in the object immediately preceding, wherein a clamping roller working in a tapered recess is pushed into engagement with the sheet material by means of hydraulic pressure.

This is a division of my co-pending application Serial No. 734,904 led March 15, 1947;for Step-by-Step Feeding Device which has matured into U. S. Patent No. 2,467,740 granted April 19, 1949.

In the drawings:

Figure 1 is a diagrammatic side elevation, partly in section, of a portion of a cutting, punching or stamping machine having a hydraulic feed and hydraulic clamping arrangement according to a preferred form of the invention;

Figure 2 is a fragmentary vertical section through the bed of the machine immediately vvadjacent one of the clamping devices, taken along the line 2-2 in Figure 1;

Figure 3 is an enlarged top plan view partly in section through the slide-mounted clampingvdei vice taken along the zig-zag line 3 3 in Figure 4;

Figure 4 is a vertical section through the slidemounted clamping device taken along the Yline 4-4 in Figure 3; and

Figure 5 is a vertical section through the slidemounted clamping device and the slide thereof taken along the line 5 5 in Figure 4.

Referring to the drawings in detail, Figure l shows a cutting, punching or stamping machine generally designated I0 with which are associated bed-,mounted and slide-mounted clamping devices generally designated I I and I2 supplied alternately with pressure fluid from a platen-operated hydraulic pump, generally designated I3. Figure l Shows a purely diagrammatic arrangementv of the mechanisms associated with the clamping devices II and I2, certain details of construction being omitted in order to simplify the showing'. While the pump I3 has been shown asseparate and distinct from theufeeding motor which it operates (Figure 1) it will be understood that in practice these may be more intimately interconnected or interrelated such as is disclosed in my co-pending application Serial No. 576,821 led February 8, 1945, for Stock Feeding Mechanism for Punching, Stamping and Cutting Machines, now Patent No. 2,428,483 issued October 7, 1947.

The machine I0 may consist, for example, of a punch press having a bed I4 and a vertically reciprocable platen or ram I5, the machine I0 being conventional and its details forming no part of the present invention. Secured to the bed I4 and platen I5 are cooperating male and female die members I6 and Il respectively having projections I8 and I9 received in recesses 20 and 2| respectively (Figure l). Also mounted on the bed I4 as by the bolts 22 is a sheet or strip feeding mechanism generally designated 23. The feeding mechanism 23 consists of a pair of parallel guide members 24 of L-shaped crosssection (Figure 2) having opposed guide grooves 25 of V-shaped cross-section and interconnected by a bridge member 26 bolted thereto as at 21. The bed-mounted or stationary clamping device Il is bolted as at 28 to the bridge member 26.

Mounted for reciprocating movement in the guide grooves 25 is a slide 29 having oppositelyly-extending ribs or flanges 30 of V-shaped crosssection (Figure 5) mating with the grooves 25. The slide 29 is provided with a socket 3I in which is secured, as by the pin 32, the forward end of a plunger 33 which at its opposite end is provided with a head 34. The head 34 reciprocates in the bore 35 of a hydraulic cylinder 36. The latter is provided with a closure 3l having a bore 38 through which the plunger 33 passes. The usual packing gland (not shown) is provided to prevent leakage around the plunger 33. The cylinder 36 is provided at its opposite ends with ports 39 and 40 to which are connected pipes'4I' and 42 leading to ports 43 and 44 (Figure 1) in the opposite end plates 45 and 46 of a hydraulicv cylinder 41. Y

The cylinder 4l contains a double-headed piston 48 having heads 49 and 50 interconnected by a neck 5I having a transverse bore 52. The bore 52 vreceives the rounded end of a crank 53 mounted on a shaft 54 and having arms 55 and 5B through which are threaded limit screws'5l and 5B, the ends of which engage a projection 59 extending laterally from an arm 60 loosely mounted on the shaft 54. The outer end of the arm 66 carries a pin 6I engaging a slot 62 in a bracket 63 bolted as at 64 to the platen I5.l

Consequently, when the platen I reciprocates, it swings the arm 60 through the pin and slot connection 6|, 62, causing the crank 53 to swing through a length of stroke determined by the adjustment of the limit screws 5l, 58, and consequently reciprocating the piston 48.

The clamping devices II and I2 are of similar construction, hence one description will suffice for both. Each is provided with a block-like casing 65 (Figures 4 and 5) having a port 66 into which is threaded a connection 6l. The connection 6l of the stationary clamping device II is connected by a branch pipe 68 to the pipe 42 whereas that of the movable clamping device I2 is connected by a flexible branch pipe 69 to the pipe 4 I The port 66 opens into a downwardly-inclined passageway 'i0 (Figure 4) leading to a laterally elongated chamber 'II closed by an elongated plate 'I2 bolted as at 13 to the casing 65. Lead- .ing downwardly from the chamber 'II are multiple bores 'I4 which receive pins l5 forming ,plungers The pins 'I5 are urged vinto engagement with a laterally elongated roller I6 (Figure 3) by means of coil springs TI. The roller 'I6 is mounted in a recess 'i8 with a tapered wall I9 inclined downward relatively to the bottom wall 80 of the casing 65. The latter rests upon the sheet or strip 8l forming the workpiece and this, in turn, rests upon the upper surface 82 of the slide 29 (Figure 5). Bolts 83 pass downward through the casing 65 of the movable clamping device I2 in order to secure it to the slide 29.

The workpiece 8| is guided at its edges by grooved guide wheels 84 (one only being shown) which are rotatably mounted upon vertical axles 85 (Figure l) seated in bores 86 in slide blocks lil of T-shaped cross-section. Those are mounted in 'a T-slot 88 by which they may be moved to and fro laterally to adjust them to different widths of workpiece 8 I.

In the operation of the invention, a workpiece 8I., such as a strip of material, for example sheet steel, is inserted between the guide wheels 84 and passed through the chambers 'I8 of the clamping devices Il and I 2 and into the space between the punch I6 and die I'I (Figure l). When the platen I5 is moved .downward it swings the arm 66 downward and this, in turn, swings the crank 53 to the right, moving the doubleheaded piston 48 to the right, This causes pressure fluid to be transmitted through the pipe 42 and port 43 into the left-hand end of the cylinder 36, causing the head 34 on the plunger 33 to be moved to the right, carrying with it the slide 29 and movable clamping device I2. At the same time, pressure iluid passes through the branch pipe B8 and passageway 'I0 of the stationary clamping .device II into the chamber 1I. This pressure fluid urges the piston-like pins 'I5 downward to the right (Figure l) forcing the roller 'I6 against the inclined Wall 'I9 of the recess 18, so that it tightly engages the workpiece 8l by wedging action and forces it against the bridge member 26. This holds the workpiece firmly in a stationary position while the punch I6 and die I'I perform their work.

Meanwhile, the travel of the piston 48 to the right creates a suction in the left-hand end of the cylinder 4l (Figure 1), causing a corresponding suction to be created in the right-hand end of the cylinder 36, withdrawing fluid therefrom through the pipe 4I. The same suction also withdraws fluid from the chamber 'II of the movable clamping device I2 by way of theflexible pipe 69, releasing the grip of the piston pins 'I5 upon the roller 'I6 (Figure 3) and terminating its wedging action against the workpiece 8I. As a consequence, the slide 29 and movable clamping device I2 are free to slide as a unit to the right on a retraction stroke, preparatory to starting a new feeding stroke.

After. the punch I6 'and kdie I1 .have performed their work and the platen I5 moves upward, the upward swinging of the arm 60 moves the crank 53 to the left and with it the double-headed piston 48. This causes pressure fluid to be pumped from the left-hand end of the cylinder 4l through the pipes 4l and 69 into the righthand end of the feeding cylinder 36 and also into the chamber Il of the movable clamping device I2. This action causes the head 34, plunger 33 and slide 29 to move to the left, shifting the workpiece 8i another step beneath the punch I6 while at the same time the piston pins 'I5 jam the roller 'I6 of the movable clamping device I2 tightly into engagement with the workpiece 8l and holding it securely against the slide 29. The workpiece 8|, being thus tightly clamped to the slide 29, is fed along with it as the slide y29 reciprocates to the left.

While this is going on, the suction developed in the right-hand end of the cylinder 41 by the travel of the double-headed piston 48 to the left, creates a suction in the left-hand end of the feeding cylinder 36, withdrawing fluid therefrom through the pipe 42, and at the same time withdrawing fluid from the chamber Il of the stationary clamping vdevice II. This action releases the grip of the piston pins 'I5 upon the roller 'I6 of the clamping device II, causing it to release its grip upon the workpiece 8| so that the latter slides freely over the bridge member 26 as the workpiece 8l is advanced by the clamping action of the clamping device I2.

In this manner, the workpiece 8I is advanced step by step in synchronism with the motion of the platen I5, causing the workpiece 8I to be punched successively by the punch I6 and die I'I. The clamping devices II and I2 are always in synchronism since they are alternately subjected to the same pressure and suction of the uid used to operate the plunger 33 in the feeding cylinder 36.

The feeding cylinder 36, for purposes of simplicity, is shown as having a fixed stroke. It may, however, be provided with an adjustable stroke by adopting the construction shown in my above-mentioned co-pending application Ser. No. 576,821 filed February 8, 1945.

What I claim is:

1. A selectively applicable and releasable pressure fluid clamping and feeding device for an intermittent sheet metal feeding mechanism serving a sheet metal stamping, cutting or punching machine, said clamping device comprising a casing structure having a slot therethrough for the passage of said sheet metal, said slot having spaced upper and lower walls, with a wedge-shaped recess adjacent one of said walls and having a recessed wall inclined relativelyY thereto, an elongated wedging roller disposed in said recess and engageable with said inclined wall, a plurality of spaced cylinder bores disposed in said casing structure with their axes Vsubstantially parallel to one another, said cylwith said roller, and a pressure fluid supply passageway opening into said cylinder bores and having a connecting portion adapted to be connected to a source of pressure fluid.

2. A selectively applicable and releasable pressure uid clamping and feeding device for an intermittent sheet metal feeding mechanism serving a sheet metal stamping, cutting or punching machine, said clamping device comprising a casing structure having a slot therethrough for the passage of said sheet metal, said slot having spaced upper and lower walls, with a wedgeshaped recess adjacent one of said Walls and having a recessed wall inclined relatively thereto, a chamber interconnecting said cylinder bores behind said pistons, a plurality of spaced cylinder bores disposed in said casing structure with their axes substantially parallel to one another, said cylinder bores being inclined relatively to said lower wall and with their axes directed toward said roller, a clamp-operating piston reciprocably mounted in each cylinder bore and engageable with said roller, and a pressure fluid supply passageway opening into said chamber and having a connecting portion adapted to be connected to a source of pressure uid.

3. A selectively applicable and releasable pressure fluid clamping and feeding device for an intermittent sheet metal feeding mechanism serving a sheet metal stamping, cutting or punching machine, said clamping device comprising a casing structure having a slot therethrough for the passage of said sheet metal, said slot having spaced upper and lower Walls, with a Wedge-shaped recess adjacent one of said walls and having a recessed wall inclined relatively thereto, an elongated wedging roller disposed in said recess and engageable with said inclined wall, a plurality of spaced cylinder bores disposed in said casing structure with their axes substantiallly parallel to one another, said cylinder bores being inclined relatively to said lower wall and with their axes directed toward said roller, a clamp-operating piston reciprocably mounted in each cylinder bore and engageable With said roller, and a pressure fluid supply passageway opening into said cylinder bores and having a connecting portion adapted to be connected to a source of pressure fluid, said casing structure having an upper casing half and a lower casing half abutting one another adjacent said slot. JOHN HALLER.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date 1,851,678 Mayer Mar. 29, 1932 2,349,114 Russell May 16, 1944 2,349,520 Ripley May 23, 1944

Images