GB2167333A - Pipe bending tool - Google Patents

Abstract

A hand tool for use in bending automobile brake pipes 24 without producing flats or creases comprises a pair of jaws provided with arcuate grooves 11, 12 about which the pipe may be bent. The grooves extend laterally of the jaws from one pair of side surfaces 5, 6, across the mating surfaces 9, 10 and across the other pair of side surfaces 13, 14. When the jaws are in mating contact the grooves form a circular orifice at the one surface in which the pipe is clamped prior to bending. Bending is achieved by forming the clamped pipe to the arcuate shape of one of the grooves. <IMAGE>

Description

SPECIFICATION Bending tool The present invention is concerned with a tool used for bending small bore pipes about a small radius. the tool may be a hand held tool and the pipes automobile brake pipes.

There is a general problem in forming small radius bends in narrow bore pipes, such as automobile brake pipes, and a particular problem where the bend is required to be formed adjacent a nut fitment retained on the end of the tube which may, for example, have been flared so that the nut fitment is not removable.

Present methods of bending such pipes tend to introduce undesirable flats and distortions in the area at and adjacent the bend.

I have now developed a tool, which is preferably a hand held tool, that substantially overcomes these problems and enables an operator to hold and form small radius bends directly in narrow bore pipes.

Accordingly, therefore, my invention provides a tool for use in bending small bore pipes comprising: a pair of arm portions pivotally connected adjacent one end thereof to provide at said one end a pair of jaws movable towards and away from each other, said jaws having mating face portions and first and second surfaces adjacent said face portions, the other end of said arms being movable to open and close said jaws and to urge said faces into mating relationship; an arcuate groove formed in each said jaw extends from one of said first or second surfaces across a said mating surface to meet and extend across the other said surface on at least one of said jaws, the grooves in each said jaw being shaped and positioned such that with the mating faces in contact a circular orifice is formed in one of said first or second surfaces.

The said other end of said arms may be in the form of handles whereby manual pressure is used to bring them into their nearmost positions and thereby to urge the mating faces into contact.

The handles may include means for locking them in their nearmost positions. In an alternative arrangement the handles may be activated by mechanical, pneumatic or hydraulic means.

Preferably the grooves adjacent said one surface initially extend substantially parallel to each other whereby a short tubular portion extends from said circular orifice when the mating faces are in contact.

The radius of the groove is preferably substantially equal to the outside radius of the tube that requires bending.

One embodiment of the invention will now be described with reference to the accompanying diagrammatic drawings in which: Fig. 1 is a plan view from one side of a hand tool of the invention.

Fig. 2 is a side elevation in the direction of arrow C on Fig. 1, Fig. 3 is a plan view of the other side of the tool of Fig. 1, Fig. 4 is a view taken along the line A-A of Fig. 3 in the direction of arrow B, Fig. 5 is a sectional view of a brake pipe held in the jaws of the tool of Figs. 1-4, Fig. 6 is a section of the brake pipe of Fig.

5 after bending.

In this embodiment the tool is a hand tool having the general form of a pair of tongs comprising a head portion 4 consisting of a pair of jaws having upper surfaces 5 and 6 and lower surfaces 13 and 14. Each jaw forms part of cranked arms 1 and 2, having handles 7 and 8 respectively, that are pivotally connected through pin 3.

The jaw portions have parallel mating surfaces 9 and 10. Arcuate grooves 11 and 12 are formed in the said mating surfaces and extend from upper surfaces 5 and 6 across mating surfaces 9 and 10 and lower surfaces 13 and 14, as illustrated in Fig. 3, to form recesses in the sides of the arm portions, e.g., 12' in side 7' of arm 7 (fig.2) The said grooves have semi-circular sections such that when the mating surfaces 9 and 10 of the jaws are in contact the grooves form a circu lar orifice 20 between surfaces 5 and 6 (Fig.

1).

It is preferable that the grooves extending from surfaces 5 and 6 are initially substantially parallel thereby providing orifice 20 with a short tubular portion adjacent said upper surfaces 5 and 6. The radius of the grooves is governed by the outside radius of the pipe to be bent and should be such that the pipe can be held firmly between the jaws of head 4 by manual pressure on handles 7 and 8.

In use handles 7 and 8 move to open the jaws of head 4 to receive a portion of the pipe e.g., an automobile brake pipe, that requires bending. The pipe is then clamped between the jaws in the upper end of grooves 11 and 12 by exerting a clamping pressure on handles 7 and 8 and the pipe is then bent round one of grooves 11 or 12 acting as a former.

Fig. 5 illustrates an automobile brake pipe 24 clamped in orifice 20 formed by grooves 11 and 12. A threaded fitment 22 is retained on the pipe 24 by the outwardly flared portion 21 of pipe 24. As shown the upper surfaces 5 and 6 of jaws 4 lie against the nut portion 23 of fitment 22. The radius of grooves 11 and 12 is equal to the outside diameter of pipe 24, the pipe is firmly clamped in position and with pressure applied to handles 7 and 8 to maintain faces 9 and 10 in contact, can be bent around groove 12 to provide a bend, as shown in fig. 6, immediately behind the nut 23 of fitment 22, and having a uniform sub stantially circular cross-section.

It is preferable that the grooves 11 and 12 initially extend from surfaces 5 and 6 in a substantially parallel relationship to form a short tubular section that provides a clamp to hold the brake pipe against sideways or other movement between the jaws prior to bending.

To assist the user known means may be provided to maintain the handles in a closed position and restrain the jaws from opening under pressure applied by a pipe during the bending operation.

Although the invention has been described with reference to bending automobile brake pipes it may, of course, be applied to bending any small bore piping. Thus, the invention may, for example, be used to bend pyrocabling and microbore piping for central heating systems. In general pipes of up to 9.5 mm diameter can be bent by the tool of the present invention.

Claims (8)

1. A tool for use in bending small bore pipes comprising: a pair of arm portions pivotally connected adjacent one end thereof to provide at said one end a pair of jaws movable towardsand away from each other, said jaws having mating face portions and first and second surfaces adjacent said face portions, the other end of said arms being movable to open and close said jaws and to urge said faces into mating relationship; an arcuate groove formed in each said jaw extends from one of said first or second surfaces across a said mating surface to meet and extend across the other said surface on at least one of said jaws, the grooves in each said jaw being shaped and positioned such that with the mating faces in contact a circular orifice is formed in one of said first or second surfaces

2.A tool according to claim 1 wherein the other end of said arms is in the form of a handle whereby manual pressure may be exerted to urge the mating faces into contact.

3. A tool according to claim 2 wherein the handles include means to lock them in their nearmost positions in order that the jaws are not forced apart by bending pressure applied to the said pipe.

4. A tool according to any one of claims 1-3 wherein the grooves initially extend from said one surface in parallel directions whereby a short tubular portion is formed by said faces when in mating contact.

5. A tool according to any one of the preceding claims wherein the radius of each said groove is substantially the same as the outside radius of the pipe to be bent.

6. A tool according to any one of the preceding claims wherein the pipe is an automobile brake pipe.

7. A tool according to any one of the preceding claims wherein the said grooves extend across each said other surface adjacent each said mating face.

8. A tool substantially as herein described with reference to Figs. 1-4 of the drawings.