GB2300373A - Device for bending elongate material - Google Patents

Abstract

A portable, hand operated bending machine comprises a machine body (11), at least one former (12, 13) carried by the body (11), a tube retainer (14) secured to the body to hold part of a tube during deformation of part of the tube about the former, a pair of operating arms (15, 16) one of which is a support arm (15) rigidly secured to the machine body, and the second arm (16) being a deformation arm pivotally secured to the machine body and carrying deformation means (17, 18) for applying bending pressure to the tube to cause it to be bent around a former (12, 13) during movement of the arms one relative to the other, the support arm (15) being of a tubular form having an internal passage of substantially uniform diameter which extends through the machine body (11).

Description

DEVICE FOR BENDING ELONGATE MATERIAL This invention relates to a device for bending elongate material such as strips, including tubes, of metal and other permanently deformable materials.

A requirement to bend metal tubes arises often when installing electrical conduits and gas or water supply pipes. Installation is facilitated by use of a tube bending device of a portable type which can be used at the installation site, and various types of hand held portable bending machines are known.

Known hand held type bending machines typically comprise a metal body which carries at least one arcuate former having a circumferentially extending groove of semi-circular cross-sectional shape and into which a tube can be deformed from a straight to a curved form having a curvature corresponding to that of the radius of curvature of the circumferentially extending groove.

Deformation of tube material typically is achieved by moving a pair of arms relative to one another, one arm being a support arm fixed to the body of the device and the other arm being a deformation arm pivotally mounted relative to the body and carrying a roller against which the tube material bears, either directly or indirectly, and is caused to wrap around the former, within the former groove, as the arms are moved one relative to the other.

In the design of a hand held portable bending machine of the aforedescribed type it is necessary to provide a strong and robust construction whilst ensuring that the device remains suitably light in weight.

A particular difficulty arises in providing a portable bending machine which is able to bend material such as stainless steel tube that, in contrast copper tube of the same diameter and wall thickness, is less easily deformed.

In accordance with one of its aspects the present invention provides a portable, hand operated bending machine comprising a machine body portion, at least one former carried by that body, and the body having a tube retainer to hold part of a tube or other elongate member during deformation of an adjacent part of the elongate member about the former, a pair of operating arms, one of said operating arms being a support arm rigidly secured to the machine body and a second of said arms being a deformation arm pivotally secured to the machine body and carrying deformation means for applying bending pressure to the elongate material to cause it to be bent around the former during movement of the arms one relative to the other, wherein the support arm is of a tubular form and defines an internal passage of substantially uniform diameter which extends though the machine body.

Preferably the support arm is rectilinear. It is further preferred that the support arm has an end region in the vicinity of the machine body which extends at least 2 cm, for example between 2 and 10 cm, beyond the machine body and may serve to reinforce that body.

The machine body may be of a cast construction and may be cast around the support arm, for example by a high pressure die casting technique.

The machine body may have secured thereto two or more formers each adapted for receiving tubes of different outer dimensions(s). The operating arm may comprise deformation means in the form of a roller and that roller may either be profiled to have an outer groove of part circular shape to bear directly against the outer surface of a tube, or it may for example be flat, i e have a cylindrical outer surface, which may, for example, be utilised to bear against a deformation bar positioned between the tube and roller. The support arm may comprise a pair of deformation means in the case of a machine body having a pair of formers.

The retention means associated with the machine body may be a pivotally mounted retainer pivoted so as to be movable between respective positions aligned with grooves in either of two formers.

Preferably the support arm is provided with end closures and more preferably at least one of said end closures is selectively releasably secured to the arm whereby it may be removed for temporary insertion of a reinforcing member. The reinforcing member preferably has a length corresponding substantially to that of the support arm whereby, when bending a relatively stiff elongate member, the support arm may be temporarily reinforced by insertion of the strengthening member. The strengthening member preferably has an outer diameter or other crosssection corresponding to the bore of the support arm. The strengthening member may be of solid cross-section or tubular.

An embodiment of the present invention is now described, by way of example only, with reference to the accompanying diagrammatic drawing which is a perspective view of a portable, hand held, pipe bender in accordance with the present invention.

The pipe bender 10 comprises a die cast steel body 11 to which a pair of formers 12,13 of conventional construction are fixedly secured. The formers 12,13 are each provided with the usual arcuate grooves 12',13' each of a semi-circular cross-sectional shape adapted respectively to accommodate 15 and 22 mm tube. Each groove 12', 13' lies between a pair of part-cylindrical side faces 12",13".

A tube retainer 14 is pivotally mounted on the body 11 and is pivotable between respective positions aligned with the grooves 12',13' in the formers.

The machine comprises two operating handles 15,16. The handle 16 is pivotally secured to the body 11 in a conventional manner and carries a pair of cylindrical surfaced rollers 17,18 which lie in planes aligned with the respective grooves of the formers 12,13. The rollers have cylindrical outer surfaces which can bear against a deformation bar 19 (one only shown) having a grooved side 20 of a curvature corresponding to the outer surface of either a 15 mm or 22 mm tube. The deformation bar 19 also has a pair of co-planar flat edges 20' spaced to correspond with the spacing of a pair of edges 12",13" of a former 12',13'. In use the deformation bar lies between a roller 17,18 and the tube material, to cause the tube material to be deformed into the groove of a former as the operating arms 15,16 are moved relative to one another.

The operating arm 15 is in the form of a support arm that supports the body 11.

The body 11 is formed by a high pressure die casting technique, to surround an end region of the arm 15. The end 21 of the arm nearest the body 11 is arranged to extend at least 2 cm, in this case approximately 5 cm, beyond the body.

The support arm 15 is of a tubular kind having an internal passage of substantially uniform shape and dimension along substantially the whole of its length. The arm is provided with closures 22,23 at its respective ends, typically in the form of rubber caps at least one of which is adapted to be relatively readily removable to facilitate temporary insertion of a reinforcing rod when the machine is used to bend relatively stiff elongate material.

Claims (17)

CLAIMS:

1. A bending machine of a portable, hand operated type comprising a machine body portion, at least one former carried by that body, and the body having a tube retainer to hold part of a tube or like elongate member during deformation of an adjacent part of the length of the elongate member about the former, a pair of operating arms, one of said operating arms being a support arm rigidly secured to the machine body and a second of said arms being a deformation arm pivotally secured to the machine body and carrying deformation means for applying bending pressure to the elongate material to cause it to be bent around the former during movement of the arms one relative to the other, wherein the support arm is of a tubular form and defines an internal passage of substantially uniform diameter which extends though the machine body.

2. A bending machine according to claim 1 wherein the support arm is rectilinear.

3. A bending machine according to claim 1 or claim 2 wherein the support arm has an end region in the vicinity of the machine body and said end region extends beyond the machine body.

4. A bending machine according to claim 3 wherein said end region extends beyond the machine body for a distance between 2 cm and 10 cm.

5. A bending machine according to any one of the preceding claims wherein the machine body is cast.

6. A bending machine according to claim 5 wherein the machine body is cast around the support arm.

7. A bending machine according to any one of the preceding claims wherein the machine body has secured thereto at least two formers each adapted to receive tubes of different outer dimensions.

8. A bending machine according to any one of the preceding claims wherein the operating arm comprises deformation means which is a roller.

9. A bending machine according to claim 8 wherein said roller is profiled to have an outer groove of part circular shape adapted to bear directly against the outer surface of a tube.

10. A bending machine according to claim 8 wherein the roller has a flat surface.

11. A bending machine according to any one of the preceding claims and comprising a pair of formers, wherein each former has associated therewith a respective deformation means.

12. A bending machine according to any one of the preceding claims and comprising at least two grooved formers, wherein the retention means is pivotally mounted to the machine body whereby it is movable between respective positions aligned with grooves in the formers.

13. A bending machine according to any one of the preceding claims wherein the support arm is provided with end closures.

14. A bending machine according to any one of the preceding claims wherein at least one end of the support arm is provided with an end closure which is selectively releasably secured to the arm.

15. A bending machine according to any one of the preceding claims in combination with a reinforcing member adapted for insertion within the tubular support arm.

16. A bending machine according to claim 15 wherein the strengthening member has an outer diameter or other cross-section which corresponds substantially to the bore of the support arm.

17. A bending machine according to claim 1 and constructed and arranged substantially as hereinbefore described with reference to the accompanying drawing.