US3763690A

US3763690A - Press brake ram leveling

Info

Publication number: US3763690A
Application number: US00244577A
Authority: US
Inventors: J Kirincic; R Heitner
Original assignee: DREIS AND KRUMP MANUF CO
Current assignee: DREIS AND KRUMP MANUF CO
Priority date: 1972-04-17
Filing date: 1972-04-17
Publication date: 1973-10-09
Anticipated expiration: 1990-10-09

Abstract

A press brake having a ram leveling adjustment in its ram advancing means is disclosed. Adjustment can be made even though tooling is secured to the bed and ram. In a preferred embodiment, the mechanical portion of the ram advancing means includes substantially parallel, linked bell cranks, each having a pivot, and at least one of the pivots inludes an eccentric pivot pin which can be rotated to a desired position for ram leveling adjustment. Preferably the orientation of the eccentric pivot pin is adjusted, and secured after adjustment, by means of a manually operable gear system which is self-locking with respect to forces applied at the pivot pin.

Description

United States Patent [191 Kirincic et al.-

[ Oct. 9, 1973 PRESS BRAKE RAM .LEVELING [73] Assignee: Dreis & Krump Manufacturing (30.,

Chicago, Ill.

[22] Filed: Apr. 17, 1972 [21] Appl. No.: 244,577

2,353,388 7/1944 Cannon 100/258 A Primary Examiner--Richard J. Herbst Attorney-John D. Dewey et a1.

[57] ABSTRACT A press brake having a ram leveling adjustment in its ram advancing means is disclosed. Adjustment can be made even though tooling is secured to the bed and ram. In a preferred embodiment, the mechanical portion of the ram advancing means includes substantially parallel, linked bell cranks, each having a pivot, and at least one of the pivots inludes an eccentric pivot pin which can be rotated to a desired position for ram leveling adjustment. Preferably the orientation of the eccentric pivot pin is adjusted, and secured after adjustment, by means of a manually operable gear system which is self-locking with respect to forces applied at the pivot pin.

5 Claims, 6 Drawing Figures PATENTED um 9 ma SHEET 30! 3 1 PRESS BRAKE RAM LEVELING This invention relates to the manufacture and use of press brakes, and specifically to leveling adjustment.

The modern press brake is regarded as a high powered production tool, and is considered to be a versatile machine. Many kinds of press work can be accomplished quickly, easily and cheaply, with the use of tools which are readily available or which can be conveniently developed for special uses. The press brake can perform bending, forming, blanking, notching, shearing, rubber forming, multiple piercing, and other operations.

Because of the high performance characteristics which are required in the press brake construction, press brakes are expensive. In recent years there has been greater emphasis toward simplification, and other design development which help reduce the cost of manufacture of press brakes, and increase their versatility. It is well known that press brakes generally include a stationary bed and a reciprocable ram, each of which are adapted to receive the necessary tooling for the performance of the desired operations. It is also well known that it is highly desirable to provide some means of leveling the working faces of the tools, and of making and securing fine adjustments in the relative angular orientation of the tools. For example, press brakes can be used in the manufacture of elongated articles such as tapered metal light poles, and it is highly desirable to be able to make and secure adjustments in the order of thousandths of inches in the relative spacing of one or both ends of the tooling.

It is an object of the present invention to provide a highly versatile press brake having means for leveling adjustment in the mechanical portion of the ram advancing means. It is a further object of the invention to provide such a leveling adjustment by which the relative spacing of one or both ends of the tooling can be reliably and accurately changed by an operator, which adjustment is then reliably, and accurately secured and maintained during the operation of the press brake.

It is a further object of a preferred embodiment of the present invention to provide a press brake having leveling means associated with the ram, which leveling means can be manually controlled by an operator through a high mechanical advantage system, with which extremely fine adjustment in the leveling can be made as the result of relatively large adjustments by the operator in the adjustment control means of the system.

It is another object of the present invention to provide press brake leveling means which are characterized by simplicity of design, and are furthermore operable without disturbing the attachment of tooling which is secured to the bed and/or ram.

These and other objects which will be apparent hereinafter are achieved in accordance with the present invention which is described generally, and in connection with a particularly preferred embodiment, with'the aid of the accompanying drawings in which:

FIG. 1 is a perspective view of an improved press brake in accordance with the present invention;

FIG. 2 is a highly simplified elevational illustration of hydraulic and mechanical elements involved in advancing and returning the ram of the press brake shown in FIG. 1;

FIG. 3 is an enlarged fragmentary front view of the upper right hand portion of the press brake illustrated in FIG. 1;

FIG. 4 is a cross sectional view taken approximately along the line 4-4 of FIG. 3;

FIG. 5 is an enlarged cross sectional view taken approximately along the line 5-5 of FIG. 4; and

FIG. 6 is an enlarged fragmentary partially cut-away front view of the adjustment gear box shown in the upper righthand portion of FIG. 1.

Referring now to the figures, a press brake is generally indicated at 10. Brake 10 comprises a frame, generally indicated at 12, a stationary bed or lower blade, generally indicated at 14, a ram or upper blade, generally indicated at 16 and hydraulic-mechanical power means, generally indicated at 18, for advancing and returning ram 16.

The main press brake frame 12 is fabricated of steel plate, and press brake frames are conventionally designed for minimum accepted deflection. Frame 12 is fabricated by welding steel plates including side plates 20, and cross members 22. Bed 14 can be considered as contributing substantially to the rigidity since lateral portions 24 of bed 14 are also welded to side plates 20. Side plates 20 rest on feet portions 26. The nature of the conventional platens and conventional upper'or lower die sets which can be used with press brake 10 will not be described herein since these pieces are conventional and are not part of the novel aspects of the present invention.

The hydraulic-mechanical power train means 18 for advancing and returning ram 16 are illustrated in FIG.

Referring specifically to FIG. 2, double acting cylinder 30 is pivotally supported on horizontal hinge pin 32 which is carried between

frame cross members

22, 22. Cylinder 30 is powered through hydraulic line 34 during advance of ram 16, and through hydraulic line 36 during return of ram 16. Hydraulic cylinder 30 advances and retracts cylinder rod 38 which, in turn, is pivotally attached to, and drives, master lever 40 by means of connection thereto through clevis 42 and horizontal pin 44. Master lever 40 is pivotally supported on master lever support pin 46 which is carried between frame cross members 22. Along a line passing between the centers of

pins

44, and 46 another pivot pin 48 pivotally connects tie bar 50 to master lever 40.

The other end 52 of tie bar 50 is pivotally connected to bell crank 54 through pivot pin 56. Bell crank 54 is supported pivotally by pivot pin 58 which is supported between cross members 22. Vertical links '60, and 62 are pivotally connected with master lever 40 and bell crank 54, respectively, by

pivot pins

64, 66 respectively.

Links

60, 62 are pivotally connected with ram 16 near respective ends thereof through

pivot pins

68, and 70 respectively.

Master lever 40, and bell crank 56 are both levers, each having two functioning lever arms forming an angle, each lever arm having its fulcrum at the apex of the angle. Thus, master lever 40 also falls within the definition of a bell crank. Both the master lever 40 and bell crank 56 have corresponding vertical and horizontal lever arms.

Pivots

46, and 58, respectively, serve as the apex of the respective angles formed by the respective pair of horizontal and vertical lever arms. The lever arms are not separate structures but are part of bell crank 54 and master lever 40. They include corresponding vertical lever arms between

pivots

56, 58 on bell crank 54 and between

pivots

46 and 48 on master lever 40. The other corresponding lever arms can be considered to be the imaginary horizontal lever arms between

pivot

56 and 66 in bell crank 54, and between

pivots

46 and 64 in master lever 40. The respective corresponding functional lever arms are identical in length and are substantially parallel in the preferred illustrated embodiment, and the angle therebetween is substantially 90.

Thus, the respective lever-functioning portions of master lever 40 and bell crank 54 are substantially identical in length, and the corresponding lever arms are substantially parallel. Hence lever 40 and bell crank 54 provide parallel bell cranks as part of the ram advancing means.

Comparing FIGS. 1 and 2 it will be appreciated that

pivot pins

32, 46, and 58 are supported between

cross members

22, 22. The ends of

pivot pins

32, 58 can be seen on the face of front cross member 22. Pivot pin 32 is seen to be supported in the

upward frame extensions

72, 72 which are integral with respective

frame cross members

22, 22. Pivot pin 68 can be seen in the middle left-hand portion of cross member 22 in the view of FIG. 1.

However, pivot pin 46, around which the master lever 40 pivots, is not visible in the view of FIG. 1 since it terminates within gear box 74. It will be appreciated from the following description that pivot pin 46 is an important part of the ram tilt adjustment mechanism in accordance with the present invention.

Referring now to FIG. 3 a portion of cover 76 at the lower extreme of gear box 74 is removed for the purpose of clarity of illustration. Front end of pivot pin 46 is visible in the view of FIG. 3 as is worm wheel gear 82 which is fixed to pivot pin 46. Worm gear 84 meshes with worm wheel 82, and is fixed with respect to shaft 86. Worm gear 84 and shaft 86 are rotatably supported by thrust bearings 88 at both sides of gear box 74.

Shaft 86 extends out of gear box 74 to a point beyond cross member 22. Handle 90 is rotatably attached to crank lever 92, which is fixed with respect to the end of shaft 86. Shaft 86 passes through bracket 94 which is bolted to cross member 22, and thumb screw 96 can be threaded through an opening in bracket 94 to lock shaft 86 against inadvertent rotation due to accidental bumping of handle 90 on crank lever 92.

Referring now to FIG. 4, pivot pin 46 is rotatably carried in bearings 100 at both front and rear plates 22. Bearings 100 pass through openings in plate 22-and reinforcing

collars

102, 102 which are welded to the inner side of both

cross members

22, 22. Front portion 104 and rear portion 106 within bearings 100 are concentric portions of pivot pin 46. Center portion 108 is eccentric with respect to the center of portion 104, 106 and is circular. Eccentric center portion 108 is rotatably positioned within bushing 110 which extends through an appropriate opening in master lever 40 and front and rear collars 112 which are welded to master lever 40 to provide reinforcement thereof. The eccentricity shown in FIG. 4 is exaggerated greatly for the purpose of more clearly illustrating the principles and operation of the present invention. In a preferred embodiment, the eccentricity would be such that a oneeighth inch throw would be achieved. From FIG. 4 it is also apparent that

reinforcement collars

116 and 118 are welded to master lever 40 both at the front and rear face thereof to provide reinforcement at the openings for

pins

44, 48, respectively.

It is an important aspect of a preferred embodiment of the present invention that the gear ratio of gearing system 81, by which the angular orientation of adjustment of pivot pin 46 can be changed and set manually,

for example, by rotation of crank lever 92, to be high enough that the system is self-locking with respect to forces applied to it through pin 46. When, in accordance with a preferred embodiment of this invention, which is specifically illustrated in the drawings, a worm gear 84 is used in the gearing system 81, the lead angle of the worm gear must be sufficiently steep to permit pin 46 to be rotated by rotation of crank 92, and yet be at an angle which will not permit it to be driven by worm wheel gear 82. Naturally, the exact range of usable lead angles on such a worm gear will depend on the particular dimensions of the elements coacting therewith, on the amounts of lubrication provided, on the amounts of vibration present, and on other variables. We have found that worm gears having thread lead angles in the neighborhood of nine degrees are eminently satisfactory for use in accordance with this invention. Nonetheless, it is highly desirable to provide means for locking crank shaft 86 against inadvertent rotation of crank caused by operator bumping, vibration, etc., and the illustrated embodiment, thumb screw 96 is provided for this purpose.

The specific embodiment described herein is provided for illustration, and the invention is not to be limited thereby. It will be apparent to those skilled in the art that many changes and modifications can be made without departing from the spirit or scope of the present invention. Consequently the scope of the invention is not to be limited by the illustrations provided in the disclosure, but only by the claims appended hereto.

We claim:

1. A press brake comprising hydraulic-mechanical power means for advancing and returning a ram, said power means including a plurality of bell cranks pivotally supported by a frame, at least one of said bell cranks being pivotally supported on an eccentric portion of an operator rotatable shaft rotatably supported on said frame.

2. The press brake of claim 1 wherein said shaft is attached to gear means for rotating said shaft, said gear means being self-locking with respect to forces applied to it from said shaft.

3. The press brake of claim 1 in which said shaft has worm gear means operably connected therewith, said worm gear means including a worm wheel gear fixed with respect to said shaft, and including a worm gear operably engaging said worm wheel gear, and handle means for rotating said worm gear.

4. The press brake of claim 3 in which said shaft has indicator means fixed thereto to correspond to predetermined position adjustment of said ram.

5. A press brake comprising a rigid frame, a bed, a ram, and driving means for advancing and returning the ram, limit means for limiting the length of travel of the ram while advancing and returning, said driving means comprising double acting hydraulic cylinder means for extending and retracting a piston rod, said ram being supported at a plurality of points by respective lengths pivotally attached to respective first levers of respective bell cranks, said bell cranks being pivotally connected to said frame on respective pivot shafts, said bell ton rod, at least one of said bell crank pivot shafts having an eccentric portion supporting the respective bell crank, said shaft having gearing means for rotation of said eccentric portion, said gearing means being selflocking with respect to forces applied to it from said eccentric portion.

Claims

5. A press brake comprising a rigid frame, a bed, a ram, and driving means for advancing and returning the ram, limit means for limiting the length of travel of the ram while advancing and returning, said driving means comprising double acting hydraulic cylinder means for extending and retracting a piston rod, said ram being supported at a plurality of points by respective lengths pivotally attached to respective first levers of respective bell cranks, said bell cranks being pivotally connected to said frame on respective pivot shafts, said bell cranks being connected to each other by connecting rod means at second lever arms of said bell crank, said first lever arms being substantially identical, and each of said second lever arms being substantially identical, and the angle between respective first and second lever arms being identical, one of said bell cranks including an extending arm portion pivotally secured to said piston rod, at least one of said bell crank pivot shafts having an eccentric portion supporting the respective bell crank, said shaft having gearing means for rotation of said eccentric portion, said gearing means being self-locking with respect to forces applied to it from said eccentric portion.