US3564892A - Variable radius bending fixture - Google Patents

Abstract

A MACHINE FOR BENDING LENGTHS OF TUBULAR OR ROD STOCKABOUT A BENDING DIE ASSEMBLY WHEREIN THE BENDING DIE IS COMPRISED OF A LENGTH OF CHAIN WOUND ABOUT A COMMON AXIS A SUFFICIENT NUMBER OF TIMES TO GENERATE THE REQUIRED RADIUS OF BEND IN THE STOCK.

Description

W. A. OSTERLAND Feb. 23, 1971 VARIABLE RADIUS BENDING FIXTURE '2 Sheets-Sheet 1 Filed Aug. 15, 1968 1971 w. A. OSTERLAND I ,8

VARIABLE RADIUS SENDING FIXTURE Filed Aug. 15, 1968 2 Sheets-Sheet 2 ATTORNEY United States Patent 3,564,892 VARIABLE RADIUS BENDING FIXTURE William A. Osterland, Aurora, 11]., assignor to Pines Engineering Co., Inc., Aurora, 11]., a corporation of Illinois Filed Aug. 15, 1968, Ser. No. 752,972 Int. Cl. B21d 7/02 U.S. Cl. 72-219 Claims ABSTRACT OF THE DISCLOSURE A machine for bending lengths of tubular or rod stock about a bending die assembly wherein the bending die is comprised of a length of chain wound about a common axis a sufficient number of times to generate the required radius of bend in the stock.

Bending machines generally comprise a frame upon one end of which is mounted a bending die having associated with it the usual clamp dies and a wiper die, the latter being movable about the axis of the bending die to carry the work piece around said bending die for generating a bend therein. With such machines, when a bend of a different bending radius is to be performed, it is necessary to remove the bending die and replace it with one having a different radius. This is time consuming and expensive especially in instances where but a few bends of a given radii are required or when a plurality of pieces of stock are each to be formed with sevreal bends of different radii.

The present machine is provided with a bending die assembly which can be easily and quickly changed from one radius to another without replacement of the bending die. More specifically, the bending die of the present machine is comprised basically of a carrier plate or disc of considerable diameter, having a core secured on its top surface about which a link chain or other flexible element is wound to generate the desired working radius. Winding and unwinding of the chain is accomplished by means of a motor geared to the bending die assembly and excess chain is collected on a motor driven collector reel or spool. -In order to assure that the bend stock is devoid of markings which might be generated thereon by the impression of the links of the chain, the effective area of said chain is masked by a smooth bend. The bending die assembly has, of course, associated with it the usual clamp dies and a wiper die, the latter being effective to carry the stock around the bending die a requisite distance.

It is, therefore, an object of the invention to provide a bending machine with a variable radius bending die assembly.

Another object is to provide a bending die assembly of the character to which referred.

Another object is to provide a bending die assembly of a character that can have the surface of its bending radius readily increased or decreased.

Another object is to provide a bending die assembly of a character having its bending surface comprised of a length of chain or the like wound thereon.

Another object is to provide a chain type bending die with a smooth work engaging surface.

Another object is to provide a variable radius bending die assembly of the character referred to which is not expensive or difficult to manufacture, is easy to adjust, positive in its adjustment and very efficient and satisfactory to use.

The structure by means of which the above noted and other objects and advantages of the invention are attained will be described in the following specification, taken in conjunction with the accompanying drawings, showing 3,564,892 Patented Feb. 23, 1971 a preferred illustrative embodiment of the invention, in which:

FIG. 1 is a plan view of a bending machine embodying the invention;

FIG. 2 is an enlarged plan view of the bending die assembly;

FIG. 3 is a detail sectional view taken substantially on line 33 of FIG. 2, showing parts in elevation;

FIG. 4 is a detail sectional view of the take-up reel assembly, taken substantially on line 4-4 of FIG. 2; and

FIG. 5 is a detail view of a fragment of the chain.

Referring to the exemplary disclosure of the invention as shown in the accompanying drawings, the bending machine includes a base frame 11, upon which is mounted a suitable guide 12 for a workpiece 13 which may be a length of tubular stock or rod stock. One end of the frame 11 mounts on its top surface a bending die assembly generally indicated at 14, associated clamp die assemblies 15 and 16, and a wiper die 17. The wiper die 17 is carried on a fixture 18 that is rotatable about the axis of the bending die assembly so as to carry the workpiece 13 around the bending die, as shown in dotted lines in FIG. 2, a distance required to produce the requisite bend therein.

It should be obvious that the radius of bend generated is determined by the diameter of the bending die 14. Hence, in order to change the radius of bend to be produced it is necessary to change the effective diameter of the bending die. This change is accomplished with ease by the disclosed bending die assembly. This assembly is comprised essentially of a link chain 19, or other flexible member, wrapped around the axis of the bending die assembly a sufficient number of times to generate an effective bending surface of the desired radius.

More particularly, the bending die assembly 14 is comprised of a carrier plate or disc 21 or relatively large diameter, about 48 inches, secured firmly to a hub 22 that is journalled for free rotation about a stud shaft sleeve 23 anchored firmly in the wiper die fixture 18 as by means of a stud 24 having a retaining nut 25 threaded onto its upper end. Preferably, antifriction thrust bearings 26 are arranged between the hub and stud sleeve.

The carrier plate 21 has a gear 27 secured to its bottom surface which is meshed at all times with a pinion 28 carried on the upper end of a shaft 29 that is drivingly connected with a motor 31. Preferably, a hydraulic motor is used. This assembly provides drive means for rotating carrier plate 21 for a purpose to be explained presently.

The hub 22 carries, for rotation therewith and with the carrier plate, a core 32 that has a slightly eccentric outside diameter, as best shown in FIG. 2, and to which is connected one end of the link chain 19. This chain, which is adapted to be wound on the core 32, as described presently, has its outwardly disposed surface ground down so as to be relatively smooth, as shown in detail in FIG. 5 at 33.

It should be apparent at this time that when motor 31 is operated to rotate shaft 29, the chain is wound upon or unwound from core 32 so as to increase or decrease the number of turns thereon. By so doing, there is presented a surface for the generation of a given radius of bend in the work piece which is bent therearound. Because of the eccentricity of core 32, the chain winds thereon substantially concentrically. To facilitate visual determination of the radius generated by a given number of turns of the chain, the carrier plate 21 may have on its top surface a series of indicies 34 in the form of circular lines each bearing a radius marking.

The chain 19, which is of considerable length, has its other end secured to a rewind reel 35 mounted on frame 11 adjacent to the bending die assembly. As best shown in FIG. 4, the reel 35 includes a gear 36 which is 3 meshed with a pinion 37 carried on the end of the shaft 38 of a motor 39.

In operation, the radius of bend to be performed in a length of stock is determined and the motor 31 is operated to generate the number of turns of chain to be cacumulated on core 32 to produce the required bend. Any excess chain is Wound upon reel 36. A surfacing band 41 (FIG. 2), adjustly anchored at its ends as at 42, 43, is laid over the wound chain on the bending die assembly to present a smooth work surface of the stock. The wiper die 17 then is swung around the bending die to carry the stock over and against the surfacing band 41 to produce the requisite band. Of course it may be necessary to advance the wiper die beyond the degree of bending required to compensate for spring back. In any event, a number of like bends may be produced in succession, or, at will, the radius of bend may be varied by winding or unwinding the chain to present more or less wrappings thereon and adjusting surface band 41.

Although I have described a preferred embodiment of my invention, in considerable detail, it will be understood that the description thereof is intended to be illustrative, rather than restrictive, as details of the structure may be modified or changed without departing from the spirit or scope of the invention. Accordingly, I do not desire to be restricted to the exact construction described.

I claim:

1. In a bending machine of the type including a bending die assembly, the improvement comprising a selfcontained adjustable bending die which includes a flexible element wound about an axial core a sufiicient number of turns to generate the effective bending diameter of the bending die, and means to wind and unwind said flexible element to selectively change the effective bending diameter of the bending die.

2. The bending machine of claim 1 wherein said axial core has a peripheral edge which is eccentric to cause the flexible element to wind on the core substantially concentric with the axis of the axial core.

3. The bending machine of claim 1 wherein said bending die assembly includes a disc which carries said axial core on the upper surface thereof whereby said flexible element rests on said upper surface of the disc.

4. The bending machine of claim 3 in which the peripheral edge of the axial core is concentric to cause the flexible element to wind thereon substantially concentric with the axis.

5. The bending machine of claim 1 in which the flexible element comprises a link chain wrapped around said axial core a suflicient number of turns to generate a bending radius of required dimensions.

6. The bending machine of claim 4 in which means is provided to rotate said axial core for collecting turns of chain thereon.

7. The bending machine of claim 5 in which a reel is provided to collect unused chain.

8. The bending machine of claim 7 including means to rotate the reel.

9. The bending machine of claim 5 in which a smooth strap is arranged around the wound chain.

10. The bending machine of chain 1 in which means are provided to rotate said axial core for collecting turns of said flexible element on said axial core.

References Cited UNITED STATES PATENTS 3,452,571 7/1969 Sassak 72157 3,181,331 5/1965 Wishing 72-319 2,659,411 11/1953 Bird 72--157 2,754,580 7/ 1956 Schlaich 72-148 2,819,752 1/1958 Hart 72-157 5 CHARLES W. LANHAM, Primary Examiner .M. J. KEENAN, Assistant Examiner US. Cl. X.R. 72-293, 157, 319

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