GB2236570A

GB2236570A - Cable adjusting tool

Info

Publication number: GB2236570A
Application number: GB8922233A
Authority: GB
Inventors: Janice Anne Bradshaw
Original assignee: Individual
Current assignee: Individual
Priority date: 1989-10-03
Filing date: 1989-10-03
Publication date: 1991-04-10
Also published as: GB8922233D0

Abstract

A tool for pulling a cable 36 through a passage defined by a member 38, comprises a cable receiving portion 22, cable clamping means 16 and grippable means 12 rotatable about the cable receiving portion to move the clamping means whereby the cable is pulled through the member. <IMAGE>

Description

CABLE ADJUSTING TOOL This invention relates to a cable adjusting tool and is particularly, though not exclusively concerned with a tool which may be used for adjusting a bicycle brake cable.

A typical bicycle brakes mechanism, whether side-pull-, centre-pull-, or cantilever-operated has a Bowden cable which has to be replaced from time to time because of stretching of the wire or damage to the outer sheath.

The gradual stretching of the wire causes the brake blocks to be held too far from the wheel rim in the rest position and can be compensated for by an adjuster mechanism. The adjuster mechanism generally includes a barrel, through which the wire passes, which fits against a fixed member of either the brake lever or brake mechanism and has a threaded outer surface; and an internally-threaded outer sleeve, which fits about the barrel, and which abuts an end of the outer sheath of the other of the brake lever or the brake mechanisms.

Unscrewing the outer sleeve in relation to the barrel increases the length of the adjuster mechanism to accomodate the stretching of the cable and to keep the brake blocks close to the bicycle rim when the brake mechanism is in the rest position. Alternatively, screwing the outer sleeve over the barrel decreases the length of the adjuster mechanism so moving the brake blocks away from the rim.

When a cable is replaced the brake mechanism must be compressed by holding the brake blocks against the wheel rim; the new brake wire must be passed through the cable restraining draw bolt, and the nut of the draw bolt tightened to grip the wire. All three operations must be must be performed together and usually two people are required. An inexpensive tool popularly called a "third hand" which is formed from spring steel wire is available which can be used to hold the brake blocks against the wheel rim so that only one person is required to change the cable. A disadvantage of such a tool is that it eventually loses its resilience so that it is unable to compress the brake mechanism. Furthermore such tools can be difficult to use if they are made of especially resilient material in that they are awkward to fit over the brake blocks.

A tool is available for pulling the cable through the cable restraining nut, whilst the brake mechanism is compressed either by hand or with the "third hand" tool described above, which has a scissor action one arm abutting the draw bolt, in use, and the other arm gripping and pulling the cable. Such tools are considered to be expensive.

It is an object of the present invention to provide a tool which facilitates the adjustment or replacement of cables.

According to one aspect of the invention there is provided a tool for pulling a cable through a passage defined by a member, the tool comprising a cable receiving portion, cable gripping means and grippable means rotatable about the cable receiving portion to move the gripping means whereby the cable is pulled through the member. The cable may be for example the wire of a Bowden cable.

The member may be the outer sheath of a Bowden cable or, preferably, the cable restaining draw bolt of a cycle brake.

The tool may abut the member in use. Preferably the grippable means abuts the member in use whereby it can be rotated against the member.

The clamping means may comprise a screw, bolt or similar fastener.

The cable receiving portion may comprise a passage.

The passage may be the bore of a tubular member. In such a case the cable clamping means may include an element which is located in the wall of the tubular member and which is operable to hold the cable against the inner wall of the tube. The element may be a screw.

The grippable means and cable receiving portion may be interconnected. The grippable means and cable receiving portion may be interconnected by at least one threaded portion carried by either of the grippable means and cable receiving portion. Preferably both of the grippable means and cable receiving portion are threadably connected.

The grippable means may comprise a wheel. The surface of the wheel may be textured to facilitate grip by a user.

A tool in accordance with the invention will now be described, by way of example only, with reference to the accompanying drawings, Figs. 1 and 2 in which: Fig. 1 is a plan view of the tool; and Fig. 2 is an elevation of a bicycle brake mechanism, including a cross section of a portion of the wheel showing the tool in use.

The tool 10 which is made of steel comprises a knurled wheel 12 (the "grippable means") and a tubular member 14 (the "cable receiving portion"). A screw 16 extends through the wall of the tubular member 14 into its bore 18.

The wheel 12 has a threaded bore 20 which receives a complimentarily-threaded portion 22 of the tubular member 14. The wheel 12 includes a portion 24 which extends transversely of the bore 20.

The threaded portion 22 is longer than the length of the bore 20 of the wheel 12. If the wheel is kept stationary in an axial sense and rotated about the tubular member 14, the tubular member will move up or down, in the sense of Fig. 1, according to the direction i.e. clockwise or anticlockwise of rotation of the wheel 14.

The use of the tool in drawing a cable through a member is shown in Fig. 2.

The bicycle brake mechanism 26 shown in Fig. 2 is of conventional sidepull construction, including brake blocks 28, which bear against wheel rim 30. A Bowden cable 32, which is connected to a hand-operated brake lever (not shown) governs operation of the brake mechanism 26. The cable comprises an outer sheath 34 and a wire 36. The wire is fixed to the brake mechanism by a draw bolt 38 which forms a passage 39.

A barrel adjuster 40 is provided which can be extended to compensate for the gradual stretching of the wire 36 with use.

To fit a new cable using the tool 10, the barrel adjuster 40 is screwed down to its greatest extent and the draw bolt 38 is slackened.

The wire 36 of the cable 32 is passed through the bore of the barrel adjuster 40 and through the passage 39. The end of the wire 36 is then introduced into the bore 18 of the tool 10, the screw 16 having been slackened. The tool 10 is moved along the wire 36 until it abuts the draw bolt. The screw 16 is tightened to grip the wire 36 and the brake blocks 28 are held against the wheel rim 30 either by hand or using a third hand tool.

The wheel 12 is then rotated in a clockwise manner (when viewed along the tubular member 14) which causes the tubular member to move in the direction of arrow A in Fig, 2 drawing the wire 36 through the passage 39 in the draw bolt. When any slack in the wire 36 has been taken up, further clockwise rotation of the wheel causes compression of the brake block holding levers to urge the brake blocks 28 towards the wheel rim 30. At this point the user no longer has to hold the brake blocks, or if using a third hand tool this can be removed.

The distance of the brake blocks 28 from the rim 30 can be adjusted by further rotation of the wheel 12.

When the brake blocks are in the desired position, the nut 38 of the draw bolt can be tightened to grip the wire 36.

The tool 10 can then be removed from the cable by unscrewing the screw 16 to release the wire and pulling the tool off the wire 36.

It will be appreciated that the tool of this invention can be used in fitting cables used in other situations, for example motorcycle brake cables or cycle deraillieur gear cables. The dimensions of the tool would be adjusted to suit the application. For example, in use with a relatively thick cable, such as a motor cycle brake cable, the passage 18 defined by the tubular member 14 would be relatively large.

It will also be appreciated that the tool may be conveniently formed in a plastics material.

Claims

cLAIXS

1. A tool for pulling a cable through a passage defined by a member, the tool comprising a cable receiving portion, cable clamping means and grippable means rotatable about the cable receiving portion to move the clamping means whereby the cable is pulled through the member.

2. A tool according to claim 1 in which the tool abuts the member in use.

3. A tool according to claim 2 in which the grippable means abuts the member in use whereby it can be rotated against the member.

4. A tool according to any preceding claim in which the clamping means comprises a screw, bolt or similar fastener.

5. A tool according to any preceding claim in which the cable receiving portion comprises a passage.

6. A tool according to claim 5 in which the passage is the bore of a tubular member.

7. A tool according to claim 6 in which the cable clamping means comprises an element located in the wall of the tubular member.

8. A tool according to any preceding claim in which the grippable means and cable clamping portion are interconnected.

9. A tool according to claim 8 in which the grippable means and cable receiving portion are interconnected by at least one threaded portion carried by either of the grippable means and cable receiving portion.

10. A tool according to any preceding claim in which the grippable means is substantially circular.

11. A tool substantially as described herein with reference to the drawings.