GB2331721A

GB2331721A - Shaping process

Info

Publication number: GB2331721A
Application number: GB9725256A
Authority: GB
Inventors: Stephen Clive Brooks
Original assignee: Brooks
Current assignee: Brooks
Priority date: 1997-11-29
Filing date: 1997-11-29
Publication date: 1999-06-02
Also published as: GB9725256D0; GB2331721A9

Abstract

A length of round or square hollow tubing (10), such as steel, into which a solid steel insert (11) has been introduced, is securely held between a pair of grippers (13 and 14). An axially extending force F is then abruptly imparted to the end (12) and insert (11) through an axially moveable ram (19), to cause the end of the tube (12) and the insert (11) to deform generally outwardly, to provide a shape as may be desired, particularly on the head portion of a railing. The tubing and insert may be heated during shaping.

Description

1 PATENTS ACT 1977 WLININS/A9316GB Title: Shaping Process 2331721

Description of Invention

This invention relates to a shaping process, and particularly but not exclusively to a shaping process whereby metallic or metal-like articles may be deformed.

The invention is particularly concerned with processes used to shape generally elongate metallic or metal-like members, such as are, for example, used in the manufacture of fence posts, railings and the like, and specifically, the invention is directed towards a method of forming head portions of such articles.

Conventionally, head portions of railings, fence posts and the like are formed separately from the associated fence post, which usually comprises a hollow tube, of round, square or other cross-section. Subsequent to the head portion being made, for example by forging or pressing, the head portion is welded to the tube.

As will be appreciated, welding operations are expensive, and often leave weld marks which impart an undesired appearance to the finished article.

It is thus an object of the present invention to provide an improved method which reduceis operating costs and which produces an improved result.

According to one aspect of the invention, there is provided a method of shaping an end portion of a metallic or metal-like hollow member comprising placing an insert of metallic or metal-like material in the end of the member and subsequently shaping both the end of the member and the insert.

2 The hollow member may comprise a metallic tube, of for example round or square cross-section, and the insert, of corresponding, but slightly smaller cross-section may be a length of solid bar, an ingot, or the like.

The end of the member and the insert may be shaped by a variety of methods, chosen in accordance with the desired configuration of the end portion.

In the case where it is desired that the end portion should have a crosssectional area generally equal or less than that of the remainder of the hollow member, the end portion of the hollow member and the insert may be shaped by a drop forging or pressing operation, which may of course comprise a plurality of stages during which the desired configuration is obtained in stages, and which may also comprise a subsequent pressing or machining operation in order to "finish" the operation.

In the case where it is desired that the cross-sectional area of the end portion is greater than that of the remainder of the hollow member, an upset forging operation may be used. In such a case an upset forging force may be applied to the end of the member in which the insert is located, with the member held securely by a gripping force applied thereto, such that the axially extending upset forging force causes the end of the member and at least part of the insert to "spread" radially outwardly from the axis of the member. It will of course be appreciated that as either forging operation is carried out with the end of the member and the insert in a heated state, the insert will become secured to the member during the forging operations.

In the case of upset forging, once the required increase in crosssectional area of the tube and insert has been obtained, the enlarged end may then be formed in any convenient manner, such as by subsequent pressing or machining, as desired.

The insert may be formed from the same material as the hollow member or formed from a different material. It will of course be appreciated that whilst 3 it is necessary for an end of the member to be hollow, so as to receive the insert, it is not necessary for all of the member to be hollow.

The invention is particularly suited to the manufacture of heads for metallic railings or fence posts, as operational manufacturing costs are reduced by the avoidance of the necessity for welding a head portion to the generally elongate rail or fence post. Moreover, a wide variety of differently configured heads may be manufactured by choice of appropriate subsequent forging or pressing processes, and it has been found by the applicants that the appearance of a railing or fence post with a head manufactured in this way is considerably better than if the head were manufactured separately and subsequently welded. In fact, the applicants have found that a fence post manufactured in this way closely resembles a length of solid bar, which is clearly desirable when aesthetic considerations are taken into account, such as is the case with ornamental fencing arrangements.

The invention will now be described by way of example only by reference to the accompanying drawings, wherein Figures la, Ib and Ic illustrate three stages in a preferred embodiment of the invention, which is used to produce a head portion of a fence post of greater cross-sectional area than the remainder of the fence post.

Referring first to Figure Ia. there is shown a length of round or square hollow tubing 10, conveniently of steel, into which has been introduced an insert 11, conveniently of solid form, and which preferably is of the same metallic material as the tubing 10. The end of the tubing 12 is held securely between a pair of grippers 13 and 14, each of which conveniently has an inclined bearing surface 15 and 16 terminating at generally horizontally extending parts 17 and 18, which bear upon, and hold, an outer surface of the tubina 10.

0 4 It will be appreciated from the drawing that the insert 11 is a close, conveniently interference, fit within the tubing 10, and that the insert extends only part way into the interior of the tubing 10.

Once the tubing 10 is secured between the grippers 13 and 14, an axially extending force F is then abruptly imparted to the end 12 and insert I I through an axially moveable ram 19, conveniently pneumatically, hydraulically or mechanically operated.

The axially extending force imparted by the ram 19 causes the end of the tube 12 and the insert to deform generally outwardly (in the direction of the arrows A), with the deformable metallic material thus obtaining an external configuration corresponding roughly to the shape of the bearing surfaces 15 and 16, as shown in Figure lb.

It will of course be appreciated that the radial deformation of the end of the tube and insert may be achieved in a variety of ways, and that the "preshaping" illustrated in Figure I is merely one way in which the radial expansion can be accomplished. For example, the inclined bearing surfaces 15 and 16 may not be necessary, such that the grippers 133 and 14 would comprise bearing surfaces extending generally parallel to walls of the tube, or as a further alternative, the head of the ram 19 may be configured so as to provide the required pre-shaping of the tube and insert.

Whilst in this example, only one defori-nation step is shown, it will be appreciated that in practice, the process may be repeated one or more times, in order for the end of the tubing 12 and the insert to attain the required crosssectional area and shape.

Once the end of the tubing 12 and the insert has been formed to the desired extent, the increased diameter portion may then be machined, pressed or otherwise formed so as to produce the required shape, such as a railing head as shown in Figure I c.

Whilst the applicants envisage drop forging or pressing to be the most appropriate method of forming the final head configuration, it should be understood that one of several methods may conceivably be used.

The invention as above described enables a superior effect to be obtained, in that the final appearance of (for example) a fence post and head is such that it resembles a fence post and head formed from a unitary length of solid bar. Moreover, the method by which it is manufactured is considerably simpler than those previously utilised, in that it may be achieved by a sequence of forging operations, without the necessity of undergoing expensive and relatively complex welding operations. It will of course be appreciated that the invention may similarly be used in the manufacture of vertical bar infills, which are positioned between adjacent fence posts to provide a line of fencing.

Preferably a small hole 22 is drilled or punched into an upper end portion of the tube 12, adjacent to the insert, to assist in a subsequent galvanising operation.

Whilst in the foregoing description the invention has been described as being particularly suited to the manufacture of fence posts, it will of course be appreciated that other articles may be manufactured by the use of this process, not necessarily related to the fencing industry.

The features disclosed in the foregoing description, or the following claims, or the accompanying drawings, expressed in their specific forms or in terms of a means for performing the disclosed function, or a method or process for attaining the disclosed result, as appropriate, may, separately, or in any combination of such features, be utilised for realising the invention in diverse forms thereof.

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Claims

1 A method of shaping an end portion of a metallic or metal-like hollow member comprising placing an insert of metal or metal-like material in the end of the member and subsequently shaping both the end of the member and the insert.

2 A method according to Claim 1 wherein the hollow member comprises a metallic tube.

3 A method according to Claim 1 or Claim 2 wherein the insert is a length of solid bar, having a cross-section slightly smaller than the hollow member.

4 A method according to any one of the preceding claims wherein the hollow member and the insert are shaped by a drop forging or pressing operation.

A method according to any one of Claims 1 to J3) wherein the end portion of the hollow member and the insert are shaped by an upset forging operation.

6 A method according to Claim 5 wherein the end of the member in which the insert is located is securely held by a gripping force, such that the axially extending upset forging force causes the end of the member and at least part of the insert to "spread" radially outwardly from the axis of the member.

7 A method according to any one of the preceding claims wherein the shaping operation is carried out in a heated state.

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8 A method according to any one of the preceding claims wherein the insert is of the same material as the hollow member.

9 A method of shaping an end portion of a metallic or metal-like hollow member, when carried out substantially as hereinbefore described and/or with reference to the accompanying drawings.

A method according to any one of the preceding claims, for shaping the head portion of a railing or fence post.

11 A railing or fence post, the head of which having been shaped by a method according to any one of the preceding claims.

12 Any novel feature or novel combination of features described herein and/or in the accompanying drawings.