US3826121A

US3826121A - Method and apparatus for cold bending h-shaped steel

Info

Publication number: US3826121A
Application number: US00336350A
Authority: US
Inventors: K Yashiro
Original assignee: Individual
Current assignee: Individual
Priority date: 1973-02-27
Filing date: 1973-02-27
Publication date: 1974-07-30
Anticipated expiration: 1991-07-30

Abstract

A method and apparatus for bending a grooved, H-shaped or the like shaped steel workpiece having a center web and two parallel flanges extending at right angles to and connected by the web in the plane of the web by cold-bending in which the inner surface of one of the two flanges has applied thereon an outward force by a pressure roller means and the inner surface of the other flange also has applied thereon an outward force by a pair of spaced pressure receiving roller means positioned on the opposite sides of the pressure roller means whereby the shaped steel workpiece has imparted thereto a bending moment without applying any buckling load on the web across the width thereof and the workpiece is then transferred in the longitudinal direction thereof with the workpiece held in pressure contact with the rollers.

Description

United States Patent [191 Yashiro 11] 3,826,121- [451 July 30, 1974 METHOD AND APPARATUS FOR COLD BENDING H-SHAPED STEEL [76] Inventor: Kazuyoshi Yashiro, No. 19

Miharashi-cho 2-chome, Kue-shi, Hiroshima-kemlapan [22] Filed: -Feb. 27, 1973 [21] Appl. No.: 336,350

[52] US. Cl. 72/170, 72/171 [51] Int. Cl B21d 5/14 [58] Field of Search 72/170-l75 [56] References Cited 1 UNITED STATES PATENTS 2,279,197 4/1942 Hoell 72/171 2,767,767 10/1966 Peterson 72/170 X 3,339,392 9/1967 Buckwalter et a1 72/170 X FOREIGN PATENTS OR APPLICATIONS 19,988 8/1969 Japan 72/173 Primary ExaminerMilton S. Mehr Attorney, Agent, or Firm-Wenderoth, Lind & Ponack [57] ABSTRACT A method and apparatus for bending a grooved, H- shaped or the like shaped steel workpiece having a center web and two parallel flanges extending at right angles to and connected by the web in the plane of the web-by cold-bending in which the inner surface of one of the two. vflanges has applied thereon an outward force by a pressure roller means and the inner surface of the other flange also has applied thereon an outward force by a pair of spaced pressure receiving roller means positioned on the opposite sides of the pressure roller means whereby the shaped steel workpiece has imparted thereto a bending moment without applying any buckling load on the web across the width thereof and the workpiece is then transferred in the longitudinal direction thereof with the workpiece held in pressure contact with the rollers.

4 Claims, 5 Drawing Figures PATENTEU L 3.826. 1 2 1 Fig fi'? ART F/g. 2 PRIOR ART METHOD AND APPARATUS FOR COLD BENDING II-SHAPED STEEL BACKGROUND OF THE INVENTION This invention relates to a method and apparatus for bending a shaped steel workpiece and especially, an H- shaped or grooved steel workpiece having a center web and two parallel flanges extending at right angles to and connected by the web in the plane of the web by coldbending.

A number of methods for bending an H-shaped steel workpiece or the like having a center web and parallel flanges extending at right angles to and connected by the web in the plane ofthe web by cold-bending have been proposed and practically employed. Such prior art methods may be generally exemplified as follows: a. A first prior art method According to this method, the center web of a shaped steel workpiece such as an I-I-shaped steel workpiece is cut off or sheared in the axial direction (longitudinal direction) thereof to divide the workpiece into two half portions, the half portions are individually bent to a desired curvature in the plane of the web thereof by a conventional bender and thereafter,.the bent half portions are welded together along the longitudinal cut faces thereby to obtain an H-shaped on the like shaped steel workpiece product having the desired curvature. Alternatively, two preformed T-shaped or L-shaped steel workpieces are bent to a desired curvature in-the plane of the web thereof and the'workpieces are then welded together at their legs thereby to obtain an H- shaped or a grooved steel product having the desired curvature.

b. A second prior artmethod According to this method, the opposite ends of a shaped steel workpiece are pulled by a stretcher against dies to a desired or necessary curvature or shape.

c. A third prior art method According to this method, the outer surface of one of the two flanges of a shaped steel workpiece such as an H-shaped steel workpiece is supported on apair of spaced pressure receiving rollers whereas the outer surface of the other flange has applied thereto an inward force by a single pressure roll in an intermediate position between the pair of pressure receiving rollers and the workpiece is then bent in the plane of the web thereof as the workpiece is transferred in the longitudinal direction thereof while being held in pressure contact with the rollers.

However, the first prior art method includes the welding operation which consumes a great deal of labor and time and since the obtained shaped steel product has the welded joint, the strength of the product is frequently insufficient for application as a structural member. In the second prior art method, the opposite ends of the shaped steel workpiece which have been gripped by jaws of the stretcher will be damaged to a degree that they become unserviceable and the damaged end portions have to be removed resulting in waste of material. In the third prior art method, the center web of the shaped steel workpiece is subjected to a compressive (buckling) load across its width which will buckle the web and the opposite flanges are also easily subjected to deformation. Therefore, the curvature range obtainable by this method is limited to a relatively narrow one.

SUMMARY OF THE INVENTION Therefore, one object of the present invention is to provide a method for cold-bending a shaped steel workpiece in the plane of the web thereof which can effectively eliminate the time consuming operation inherent in the above-mentioned first and second prior art methods and which includes the bending operation utilizing only the rollers as in the case of the third prior art method, but which eliminates the possibility of the buckling and/or deformation which inevitably occurs in the third prior art method.

According to one embodiment of the present invention, pressure and pressure receiving rollers are employed as in the case of the third prior art method as means for applying pressure against a workpiece, but a pressure roller means and a pressure receiving roller means apply outward forces on the flanges of a shaped steel workpiece from the inner surface of the flanges instead of merely applying pressure on the flanges from the outer surfaces thereof as in the case of the third prior art method and the pressure roller means and pressure receiving roller means apply such outward forces in opposite directions so that the workpiece has imparted thereto a bending moment with no compressive (buckling) load applied on the center web across its width and the workpiece-is then bent in its web plane by cold-rolling as the workpiece'is transferred in the longitudinal direction while being held in pressure contact with the roller means.

Thus, according to the present invention, a shaped steel workpiece can be easily and rapidly processed while eliminating the possibility of the buckling of the center web and/or the deformation of the flanges which inevitably occur in the prior art corresponding methods.

Anotherobject of the present invention is to provide an apparatus for carrying out the method.

The above and other objects and attendant advantages of the present invention will be more apparent to those skilled in the art from a reading of the following detailed description in conjunction with the accompanying drawing which shows preferred embodiments of the invention for illustration purpose only, but not limiting the scope of the same in any way.

BRIEF DESCRIPTION OF THEDRAWING FIG. 1 is a perspective view showing the abovementioned third prior art method for curving a workpiece in the plane of the web thereof by cold-bending;

FIG. 2 is an end elevational view of FIG. 1;

FIG. 3 is a front elevational view showing one embodiment for bending a workpiece in the plane of the for web thereof by cold-bending according to the present DETAILED DESCRIPTION OF THE PRESENT INVENTION For better understanding of the advantages of the present invention over the prior art, a description will first be given of FIGS. 1 and '2 of the accompanying drawing which show the above-mentioned third prior art method for bending a shaped workpiece in the plane of the web thereof by cold-bending. In these Figures, the prior art method is shown as being applied to the bending of an H-shaped steelworkpiece 10 which has a pair of opposite parallel flanges 11 and 12 and a web 13 extending between the flanges at right angles thereto and connecting them together. In bending the I-I-shaped steel workpiece 10 in the plane of the web by cold-bending, a pressure roller 14 is brought into pressure-contact with the outer or upper surface 11' of the flange l1 and a pair of spaced pressure receiving rollers 14' and 14' are brought into pressure-contact with the outer or lower surface 12 of the flange 12 and support the workpiece 10 from below whereby the workpiece has pressure applied thereto from both above and below. While being held in pressure-contact by the rollers, the workpiece 10 is bending inwardly or rearwardly as seen in FIG. 1 in the plane of the web as the workpiece is transferred in the longitudinal direction thereof (as indicated by the arrow A in FIG. 1). However, the prior art cold-bending method has the disadvantage that the flanges 11 and 12 of the workpiece 10 are likely to deform downwardly and/or upwardly, and the center web will be buckled as shown by the broken lines in FIG. 2 while the workpiece is being processed.

FIGS. 3 to 5 inclusive show preferred embodiments of the present invention in which the method of the invention is shown as being applied to the bending of H- shaped steel workpieces (identical with that shown in FIGS. 1 and 2) in the plane of the web thereof by coldbending for illustration purpose only, but the method of the invention can be equally applied to other shaped steel workpieces to be similarly processed.

Reference will be first had to FIGS. 3 and 4 which show a first embodiment of the invention. In carrying out the method of the invention, a pair of spaced pressure receiving rollers 20 are brought into pressurecontact with the inner surface 11" of the flange 11 of the workpiece on each side of the center web 13 of the workpiece spaced from the flange l2 and a pressure roller 21 is brought into pressure-contact with the inner surface 12" of the flange 12 a position between the pressure receiving rollers on each side of theweb l3 spaced from the flange 11.

With the above arrangement of pressure rollers and pressure receiving rollers, the two types of rollers cooperate with each other to apply outwardly directed forces in the opposite directions against the inner surfaces 11" and 12" of the opposite flanges 11 and 12 of the workpiece l0. Thereafter, in bending the workpiece 10 in the plane of web thereof by cold-bending, the workpiece is transferred in its longitudinal direction relative to the

rollers

20 and 21 with held in pressurecontact by the rollers. For transferring the workpiece 10 in the manner described above, the rotary shafts of the

rollers

20 and 21 are preferably connected to a prime mover (not shown) by means of gearing or the like (not shown) so as to rotationally drive the rollers. However, alternatively, the workpiece 10 can be also transferred by pulling the workpiece with a separate pulling means (not shown) which operates independently of the rollers.

The force which holds the pressure rollers and pressure receiving rollers in pressure-contact with the respectively associated flanges of the workpiece is preferably supplied from a suitable hydraulic fluid device, but any conventional pressure applying device can be employed in carrying out the invention.

According to the embodiment of the invention as just described hereinabove, in contrast with the prior art method as shown in and described in connection with FIGS. 1 and 2 hereinabove, since no buckling load is applied on the center web 13 of the workpiece 10 across the width of the web, the web will not buckle in its width direction and in addition, since the flanges l1 and 12 of the workpiece 10 will be free of any buckling load, the flanges can also be effectively protected from deformation. 7

Thus, according to the present invention, the workpiece can be bent, without causing any drawback such as that of the prior art, in the plane of the web thereof by cold-bending to a relatively great curvature.

Referring now to FIG. 5 which shows another embodiment of the invention. The embodiment of FIG. 5 is a combination of the prior art of FIGS. 1 and 2 and the embodiment of FIGS. 3 and 4. As shown in FIG. 5, a pair of first spaced pressure receiving rollers 20a are brought into pressure-contact with the inner surface 11 of the flange 11 of the workpiece 10 on each side of the center web 13, a first pressure roller 21a is brought into pressure-contact with the inner surface 12" ofthe flange 12 at a position between the pressure receiving rollers 20a on each side of the web as in the case of the embodiment of FIGS. 3 and 4, a pair of second spaced pressure rollers 20b are brought into pressure-contact with the outer surface 12' of the flange 12 in positions corresponding to the first pressure receiving rollers 20a and a second pressure roller 21b is brought into contact with the outer surface 11 of the flange 11. Thus, it will be understood that the first and second pressure rollers 21a and 21b apply forces against the flanges 11 and 12 in the same direction and similarly, the first and second pressure receiving rollers 20a and 20b apply forces against the flanges 11 and 12 in the same direction, but the force applying direction of the pressure rollers is the opposite of that of the pressure receiving rollers. After the rollers have been positioned on the workpiece 10 in the manner as described above, the workpiece is transferred in the longitudinal direction to be subjected to the bending process by cold-rolling as in the case of the embodiment of FIGS. 3 and 4.

In contrast to the above-mentioned third prior art method in which the pressure necessary for curving the workpiece in its web plane is applied on only the outer surfaces of the two flanges of the workpiece, accordingto the embodiment of FIG. 5, such pressure is also applied on the inner surfaces of the flanges of the workpiece as well as the outer surfaces of these flanges and thus, the embodiment of FIG. 5 can substantially reduce the compressive (buckling) load on the center web of the workpiece which was great in the prior art method as referred to hereinbefore and in consequence, the embodiment of this Figure can eliminate or substantially reduce the problem of the buckling of the center web and/or deformation of the flanges of the workpiece and makes it possible to bend the workpiece in the plane of the web with a relatively greater curvature than that possible by the prior art methods.

The ratio of the pressure applied by the first pressure rollers to that by the second pressure roller and the ratio of the first pair of pressure receiving rollers and that by the second pair of pressure receiving rollers can be selectively determined depending upon the shape and size of the particular steel workpiece to be processed and the desired curvature for the product to be obtained from the workpiece after the same has been processed by the present invention. It has been experimentally found that the curvature obtainable by the present invention is about two times as great as that obtainable by the prior art methods by properly selecting the values of factors, such as referred to above, concerned.

While only two preferred embodiments of the invention have been shown and described in detail for illustration purpose only, they are not to be taken as a definition of the invention, reference being had for this purpose to the appended claims.

What is claimed is:

l. A method for bending by cold bending a shaped steel workpiece such as a grooved or H-shaped steel workpiece having a center web and a pair of parallel flanges at the opposite ends of said web and connected thereby in the plane of the web of said workpiece, comprising the steps of a. applying a first outward pressure against a first flange on the inner surface thereof by a pressure roller means;

b. applying a second outward pressure against a second flange on the inner surface thereof by a pair of pressure receiving roller means positioned at positions spaced along the workpiece and on the opposite sides of said pressure roller means, said second outward pressure being in the opposite direction from the pressure applied against said first flange; and

c. transferring said workpiece in the longitudinal direction thereof while it is held in pressure-contact with said roller means for bending said workpiece in its center-web plane in the direction of said second outward pressure by cold-bending.

2. The method as set forth in claim 1, further including the steps of:

a. applying a first inward pressure against said second flange on the outer surface thereof by a second pressure roller in a position along the workpiece corresponding to that at which said first outward pressure is applied and in the same direction as said first outward pressure; and

b. applying a second inward pressure against said first flange on the outer surface thereof by a second pair of pressure receiving rollers in positions along the workpiece corresponding to that at which said second outward pressure is applied in the same direction as said second outward pressure.

3. The method as set forth in claim 1, in which the workpiece is an l-l-shaped steel workpiece which is to be bent in the plane of the web thereof by coldbending, and the first and second outward pressures are applied to the inner surface of said first and second flanges on the opposite sides of said center web of the H-shaped steel workpiece.

4. An apparatus for carrying out cold bending of a shaped steel workpiece such as a grooved or H-shaped steel workpiece having a-center web and a pair of parallel flanges at the opposite ends of said web and connected thereby in the plane of the web of the workpiece comprising:

a. a pressure roller means adapted to be brought into pressure-contact with the inner surface of one of the two flanges of the shaped steel workpiece for applying a first outward pressure against said one flange;

b. a pair of pressure receiving roller means on opposite sides of said pressure roller means and spaced therefrom in the direction of the length of the workpiece and adapted to be brought into pressure-contact with the inner surface of the other flange of said workpiece for applying a second outward pressure against said other flange; and

0. means for transferring said workpiece in the longitudinal direction thereof with the workpiece held in pressure-contact with said roller means.

Claims

1. A method for bending by cold bending a shaped steel workpiece such as a grooved or H-shaped steel workpiece having a center web and a pair of parallel flanges at the opposite ends of said web and connected thereby in the plane of the web of said workpiece, comprising the steps of a. applying a first outward pressure against a first flange on the inner surface thereof by a pressure roller means; b. applyiNg a second outward pressure against a second flange on the inner surface thereof by a pair of pressure receiving roller means positioned at positions spaced along the workpiece and on the opposite sides of said pressure roller means, said second outward pressure being in the opposite direction from the pressure applied against said first flange; and c. transferring said workpiece in the longitudinal direction thereof while it is held in pressure-contact with said roller means for bending said workpiece in its center-web plane in the direction of said second outward pressure by cold-bending.

2. The method as set forth in claim 1, further including the steps of: a. applying a first inward pressure against said second flange on the outer surface thereof by a second pressure roller in a position along the workpiece corresponding to that at which said first outward pressure is applied and in the same direction as said first outward pressure; and b. applying a second inward pressure against said first flange on the outer surface thereof by a second pair of pressure receiving rollers in positions along the workpiece corresponding to that at which said second outward pressure is applied in the same direction as said second outward pressure.

3. The method as set forth in claim 1, in which the workpiece is an H-shaped steel workpiece which is to be bent in the plane of the web thereof by cold-bending, and the first and second outward pressures are applied to the inner surface of said first and second flanges on the opposite sides of said center web of the H-shaped steel workpiece.

4. An apparatus for carrying out cold bending of a shaped steel workpiece such as a grooved or H-shaped steel workpiece having a center web and a pair of parallel flanges at the opposite ends of said web and connected thereby in the plane of the web of the workpiece comprising: a. a pressure roller means adapted to be brought into pressure-contact with the inner surface of one of the two flanges of the shaped steel workpiece for applying a first outward pressure against said one flange; b. a pair of pressure receiving roller means on opposite sides of said pressure roller means and spaced therefrom in the direction of the length of the workpiece and adapted to be brought into pressure-contact with the inner surface of the other flange of said workpiece for applying a second outward pressure against said other flange; and c. means for transferring said workpiece in the longitudinal direction thereof with the workpiece held in pressure-contact with said roller means.