US3324704A

US3324704A - Press brakes

Info

Publication number: US3324704A
Application number: US386225A
Authority: US
Inventors: Savory Frederick Ralph
Original assignee: Steel Construction and Engineering Co Notts Ltd
Current assignee: Steel Construction and Engineering Co Notts Ltd
Priority date: 1963-08-09
Filing date: 1964-07-30
Publication date: 1967-06-13
Anticipated expiration: 1984-06-13
Also published as: CH420027A; GB1001999A; SE320641B

Description

F. R. SAVORY June 13, 1967 PRESS BRAKES 5 Sheets-Sheet 1 Filed July 30, 1964 Mil/1, 159M 3 5 F. R. SAVORY June 13, 1967 PRES S BRAKE S 5 Sheets-Sheet 5 Filed July 30, 1964 W Z w MA, iwwz WW United States Patent 3,324,704 PRESS BRAKES Frederick Ralph Savory, Sutton-in-Ashfield, Nottinghamshire, England, assignor to Steel Construction & Engineering Co. (Notts) Limited Filed July 3!), 1964, Ser. No. 386,225 Claims priority, application Great Britain, Aug. 9, 1963, 31,460/63 2 Claims. (Cl. 72-453) This invention relates to press brakes, and more particularly to press brakes for bending sheet metal into box sections.

When forming a box section from sheet metal one of the tool-carrying beams (usually the movable one) of a press brake extends within the box section to form rightangle or other angle bends, radiused corners or curved bends, and lies between the closing edges of the sheet metal as the final bend is formed. To remove the formed box section from the press brake the closing edges of the sheet metal must remain sufiiciently separated to permit withdrawal of the beam relatively from the formed box section, the closing edges of the box section being brought adjacent each other, and welded or otherwise secured together, if desired, after removal from the press brake. The bringing together of the closing edges may be diflicult to achieve, particularly with heavy guage metal, and may result in a permanent stressing of the metal when the closing edges are secured together. In addition, the stroke of the movable tool-carrying beam of a press brake must be considerable to permit withdrawal, often needing to be greater than the largest cross-sectional dimension of a box section to be formed, with the result that the press brake has a dimension in the direction of movement of the movable beam that is inordinately large as compared with the actual bending portion of the working stroke and a consequently slow cycle of operation.

It has been known to provide a press brake with a completely removable guide frame and drive connection for one end of one of the tool-carrying beams (again, usually the movable one) so that a box section may be removed endwise after removal of the guide frame and drive connections, but the improvement gained in enabling the formation of complete box sections and in shortening the stroke has been greatly--if not completelyofiset by the time and labour involved in removing and replacing the guide frame and drive connection.

According to the present invention, a press brake comprises a fixed tool-carrying beam, a movable tool-carrying beam, a pair of hydraulic rams connected one between each adjacent pair of ends of the tool-carrying beams, and means for supplying hydraulic fluid under pressure to the rams, the connection of one of the hydraulic rams between the tool-carrying beams including a link pivotally connected at one end to one of the tool-carrying beams and pivotally connected at the other end to the hydraulic ram, that ram being carried by the other tool-carrying beam and one of the pivotal connections of the link being removable. Withdrawal of the removable pivotal connection breaks the connection between the beams, at that end, and the link can be swung about its other pivotal connection to permit endwise removal of a box section formed around one of the tool-carrying beams.

Means is preferably provided on the fixed tool-carrying beam adjacent the other hydraulic ram (i.e., the one without the pivotal link) to support the movable tool-carrying beam in cantilever condition when the removable pivotal connection of the pivotal link is withdrawn and avoid imposing any bending moment on that ram. Thus a cross-bar may be carried by pillars on the fixed tool-carrying beam and span the edge of the movable beam opposite to the tool-carrying edge; the connection between the beams including the ram without the pivotal link preferably also includes a single pivot permitting limited swinging of the movable beam in its own plane, so that the ram cannot take any bending moment when the movable beam is in cantilever conditionthe pivotal connection being removable for maintenance purposes only. The pivotal link may be provided with a removable locking pin enabling the movable beam to be secured parallel to the fixed beam.

The pivotal link is preferably a double-plate link, with one plate on each side of the beam to which the link is pivoted, so that the working load will not impose a bending moment on the link and/ or the rams.

The removable pivotal connection preferably comprises a taper pin, so that any play, e.g., due to wear, can be taken up, the taper pin having a screwed stern extending axially from its smaller end for engagement by a nut, which is preferably captive.

A preferred embodiment of the invention, and a slight modification, will now be described by way of example only and with reference to the accompanying drawings, in which FIGURE 1 is a front elevation of the press brake, ready for performing bending operations;

FIGURES 2 and 3 are elevations of the right-hand and left-hand ends respectively of FIGURE 1;

FIGURE 4 corresponds to the right-hand end of FIG- URE 1, but shows the press ready for removal of a completed box section (not shown);

FIGURE 5 corresponds to the upper left-hand end of FIGURE 1, but shows a press brake provided with cropping and notching tools; and

FIGURE 6 is an elevation of the left-hand end of FIG- URE 5, partly in section on the line VI--VI in that figure.

Referring to FIGURES 1 to 3, a fixed beam 10 forms the upper part of a frame below a movable beam 11, with

hydraulic ram cylinders

12A, 12B secured to the ends of the frame with their piston rods 13A, 13B extending upwardly for connection to the movable beam, one connection consisting of a split collar 14 a lock-nut 15 permitting limited pivoting of the movable beam, and the other connection consisting of a double-plate link 16 with one plate 17 on each side of the movable beam and a block 18 screwed on the piston rod 13A, the link being connected to the block by a non-removable pivot pin 19 and to the beam by a removable tapered pivot pin 20 with a lock-nut 21 held captive to the link by a split collar 22 engaging a neck in the nut and bolted to the link.

The block 18 has shoulders 23 extending over the thickness of the link plates 17, and the sides of the shoulders and the lower ends of the link plates are sandwiched between guides 24 with bearings pads 25 which do not extend into the gap between the beams. The pivot pin 19 between the block 18 and the link 16 is confined by the guides 24. The cylinder 12A is bolted to the underside of a circular plate 26 (with a radial slot 27) Welded across the bottom edges of the guides 24 and of an upper frame plate 28, which is welded to a vertical longitudinally-extending web plate 29 of the fixed beam 10, and flanked by a pair of spaced leg-forming lower frame plates 3% which are welded edge-to-edge to the upper frame plate. The piston rod 13A extends below the piston into a secondary cylinder 31 of smaller diameter, and there serves as a piston (as well as a guide) for effecting the return stroke (i.e., lifting) of the movable beam 11, as will be described presently.

At the other end of the press brake the other rain cylinder 12B is bolted to the underside of a similar circular slotted plate 26, but the guides 24 are replaced by a pair of gussets 32 supporting an extension 10X of the fixed beam beyond an end frame otherwise similar to the first.

3 The piston rod 13B is similar to that of the first cylinder unit, but in the second cylinder unit the extension serves as a guide only. The piston rod 13B screws into a coupling 33 on the lower end 34 of a secondary rod 13X which passes through a hole 35 in the extension 10X of the fixed beam 10 and a steady 36 bolted on that beam, the upper end of the secondary rod having an upwardlyfacing shoulder 37 to support the split collar 14 a reduced shank 38 passing with appreciable clearance through a hole 39 in an upright boss 40 in the movable beam 11, and a screwed end 41 for the lock-nut 15. The lock-nut has a part-spherical convex bottom surface 42 mating with a corresponding concave top surface 43 of the boss in the movable beam and the boss has a part-cylindrical convex bottom surface 44 of a radius exceeding the radius of the top surface by the depth of the boss and extending transversely of the beam, the split collar 14 having a corresponding concave upper surface 45 to mate with the bottom of the boss but interrupted by slots 46 for a pair of keys 47 which also engage slots 48 in the bottom of the boss, to prevent lateral displacement whilst permitting pivoting of the movable beam 11 in a vertical plane.

The movable beam has an extension 11X overhanging the extension 10X of the fixed beam 10 and normally bridged by a cross-bar 49 with a screw-down stop 50 bolted to the tops of two pillars 51 the lower ends of which screw into holes in the extension of the fixed beam. The usual grooves 52 and rebate 53 are provided along the length of the beams for attachment of

press tools

54, 55.

The feet of the leg-forming plates 30 are connected in pairs longitudinally by side channel members 56, which are connected at a number of intermediate positions by transverse channel members 57 providing support for a motor 58 and pump 59 for the rams and an oil reservoir 60, the side channels being welded to the leg-forming plates and the transverse channels being welded to the side channels, and the motor and the reservoir being bolted tothe channels.

The

cylinders

12A, 12B are operated in tandem for the working stroke, i.e., oil is supplied under pressure by the pump 59 to the upper end of the cylinder 12B the lower end of which is connected to the upper end of the cylinder 12A, pressurising of the upper end of the cylinder 12A being effected by transfer of oil from the lower end of the cylinder 1213. The smaller secondary cylinder 31 of the cylinder unit 12A only effects rapid return of the movable beam under the same pressure as for the working stroke, oil from the upper end of the cylinder 12A being transferred back to the lower end of the cylinder 12B.

Withdrawal of the tapered pivot pin 20 breaks the connection between the beams 10, 11, at that end, and the link 16 can be swung about its other pivot pin 19 (as indicated by FIGURE 4) to permit endwise removal of a box section (not shown) formed around the beam 11, the cylinder 12B being utilised to urge the beam 11 upwards to bring its extension 11X up against the screwdown stop 50 and hold the beam 11 in cantilever condition.

Tapped holes 61 (FIGURE 1 only) in the movable beam permit the fixing of a stiffening bar 62 (indicated in broken line) to one or both sides of the movable beam,

or of a guillotine blade (not shown) to one side in place of the press tool 55.

As shown by FIGURES 5 and 6, a modified extension 11Y of the movable beam 11 has a rebated aperture 63, into which is bolted a cropping tool 64 for co-operation with a similar tool 65 carried by a bracket 66 which is bolted to the extension 10X of the fixed beam 10 in place of the pillars 51 for the cross-bar 49, the cropping tools being providedwith corresponding holes 67 of round-, square-, and F-section for the cropping of round or square bars (as well as bars of other section which will fit the round and square holes) and of angle-, channeland T- section. A notching tool 68 is also secured to the extension 11Y for co-operation with a complementary tool 69 secured to the extension 10X of the fixed beam. Punching dies (not shown) may be secured to the extensions 10X, 11Y in place of the

notching tools

68, 69.

What I claim is:

1. A press brake comprising a fixed tool-carrying beam, a movable tool-carrying beam, a pair of hydraulic rams connected one between each adjacent pair of ends of the tool-carrying beams, and means for supplying hydraulic fluid under pressure to the rams, the connection of one of the hydraulic rams between the tool-carrying beams including a link pivotally connected at one end to one of the tool-carrying beams, and pivotally connected at the other end to the hydraulic ram, that ram being carried by the other tool-carrying beam, and one of the pivotal connections of the link being removable, together with pillars on the fixed tool-carrying beam, a cross-bar carried by the pillars and spanning the edge of the movable beam opposite to the tool-carrying edge, and a single pivot in the connection without the pivotal link, permitting limited swinging of the movablebeam in its own plane.

2. A press brake comprising a fixed tool-carrying beam, a movable tool-carrying beam, a pair of hydraulic rams connected one between each adjacent pair of ends of the tool-carrying beams, and means for supplying hydraulic fluid under pressure to the rams, the connection of one of the hydraulic rams between the tool-carrying beams including a double-plate link pivotally connected at one end with one plate on each side of one of the tool-carrying beams and pivotally connected at the other end with one plate on each side of the hydraulic ram, that ram being carried by the other tool-carrying beam, and one of the pivotal connections of the link comprising a removable taper pin having a screwed stem extending axially from its smaller end for engagement by a captive nut, together with pillars on the fixed tool-carrying beam, 2. cross-bar carried by the pillars and spanning the edge of the movable beam opposite to the tool-carrying edge, and a single pivot in the connection without the pivotal link, permitting limited swinging of the movable beam in its own plane.

References Cited UNITED STATES PATENTS 1,585,212 5/1926 Schranz 72455 CHARLES W. LANHAM, Primary Examiner.

R. D. GREFE, Assistant Examiner.

Claims

1. A PRESS BRAKE COMPRISING A FIXED TOOL-CARRYING BEAM, A MOVABLE TOOL-CARRYING BEAM, A PAIR OF HYDRAULIC RAMS CONNECTED ONE BETWEEN EACH ADJACENT PAIR OF ENDS OF THE TOOL-CARRYING BEAMS, AND MEANS FOR SUPPLYING HYDRAULIC FLUID UNDER PRESSURE TO THE RAMS, THE CONNECTION OF ONE OF THE HYDRAULIC RAMS BETWEEN THE TOOL-CARRYING BEAMS INCLUDING A LINK PIVOTALLY CONNECTED AT ONE END TO ONE OF THE TOOL-CARRYING BEAMS, AND PIVOTALLY CONNECTED AT THE OTHER END TO THE HYDRAULIC RAM, THAT RAM BEING CARRIED BY THE OTHER TOOL-CARRYING BEAM, AND ONE OF THE PIVOTAL CONNECTIONS OF THE LINK BEING REMOVABLE, TOGETHER WITH PILLARS ON THE FIXED TOOL-CARRYING BEAM A CROSS-BAR CARRIED BY THE PILLARS AND SPANNING THE EDGE OF THE MOVABLE BEAM OPPOSITE TO THE TOOL-CARRYING EDGE, AND A SINGLE PIVOT IN THE CONNECTION WITHOUT THE PIVOTAL LINK, PERMITTING LIMITED SWINGING OF THE MOVABLE BEAM IN ITS OWN PLANE.