GB2322344A

GB2322344A - Adjustable handlebar and seat extension tubes for a bicycle

Info

Publication number: GB2322344A
Application number: GB9703447A
Authority: GB
Inventors: Richard Draper
Original assignee: Individual
Current assignee: Individual
Priority date: 1997-02-19
Filing date: 1997-02-19
Publication date: 1998-08-26
Anticipated expiration: 2017-02-19
Also published as: GB9703447D0; GB2322344B

Abstract

The adjustable handlebar extension shown has a top arm with toothed sectors arranged in a fork formation (3, Figures 1a and 1c) which slot between the toothed fork formation (8, Figures 2a and 2b) of a lower arm which, in use, is received in a bicycle frame tube. The two arms are held together by a central bolt about which the top arm pivots so that it can be rotated into a required position relative to the lower arm before being secured by tightening the bolt. The pivot hole (6, Figure 1a) in the top arm is elongated, in relation to the diameter of the bolt, so that the toothed sections of each arm can be separated to allow rotation of the top arm when the bolt is slackened. When the bolt is tightened, the engaging toothed sections act to firmly lock the top arm in position relative to the lower arm. The seat extension shown in Figures 4-6 comprises similar features to the handlebar extension but the end of the top arm is adapted to support a seat instead of a handlebar.

Description

ADJUSTABLE EXENSION ARRANGEMENT FOR A PEDAL CYCLE The invention relates to an adjustable extension tube mechanism suitable for use with a seat or handlebar of a pedal cycle.

Current handlebar and seat extension tube mechanisms are well known parts of pedal cycles which allow the seat and handlebars to be attached as an extension to their respective bicycle frame tubes. They have the form of fixed tubular geometry which is clamp bolted into either the head tube or the seat tube of a bicycle frame with little or no adjustment to the position of one relative to the other being available. The distance between the centre of the handlebars and the near point of the seat is the critical dimension for individual comfort in the use of a pedal cycle. It is desirable that, due to ergonomics, each individual person using any bicycle must be able to adjust the position of the 'bars and seat in order to attain their individual comfort requirements. In addition the position of the 'bars and seat relative to the geometry of the rest of the bicycle is just as important and needs tailoring to the individual persons requirements.

According to the proposed invention there is provided an adjustable extension tube arrangement suitable for use with a pedal cycle seat or handlebars as set forth in claim 1. Note that an adjustable extension arrangement may be used on the handlebars or seat or both.

A specific embodiment of the invention will now be described by way of example with reference to the accompanying drawings in which : Figures la,lb,lc show an upper extension tube member for a handlebar, Figures 2a,2b show a lower extension tube member for a handlebar, Figures 3a to 3h show a handlebar extension tube mechanism in a range of assembled positions (omitting the central pivoting bolt).

Figures 4a,4b show a lower extension tube member for a seat, Figures 5a,5b,5c show an upper extension tube member for a seat, Figures 6a,6b show a seat extension tube mechanism at the extent of the proposed rearward adjustment and vertical position without illustrating the central pivoting bolt.

(i) Handlebar extension tube mechanism Referring to figures 1-3, an extension tube arrangement is shown suitable for use between a handlebars of a pedal cycle and a main frame of the cycle. Figure 1 shows a member 2 with a clamp 1 to secure the handle bars at one end, as used in the prior art. The opposite end comprises a plurality of disc shaped forks 3 of circular radius with toothed engaging members 4 extending through approximately 180 degrees around the outside edge of the disc section. The extent of the toothed engaging members is limited only by the point where the disc section meets he tubular section 2 to the corresponding point on the opposite side thus defining the limits of adjustability.

The adjustment range shown in the assembled configuration of fig 3 from 0 degrees (vertical) to 105 degrees.

The second, or lower, elongate member shown in figure 2 comprises toothed engaging members 7 which are designed to synchronise with the toothed engagement members 4 as described above. This will lock the two elongated members in the position required by the user and ensure that the members remain finely locked into position during use. In addition; the three forks 3 with the toothed engagement members around their end radii on member 2 are designed to slot in between the forks 8 on the lower member 9.

Therefore the complete assembled extension tube mechanism is symmetrical about its vertical axis eliminating potential imbalances.

An elongated pivotal centre bolt hole 6 in member 2 allows the entire mechanism to have its position altered without removing any of the parts from the clamped assembly.

All that will be require will be to slacken the centre bolt, disengage the toothed engagement members by sliding, rotate members 2 and 9 to the required position, reengage the toothed engagement members and tighten the centre bolt.

An 'oval' section 18 has been included in member 2 around its longitudinal axis as a means of saving weight without reducing strength.

A countersunk hole 10 allows the head of the 'long expansion bolt' to drop down between the interlocking forks 3,8. It can then be turned via a countersunk hexagonal slot in its head. The lower member 9 can be secured into the cycle frame tube in the normal way without the bolt head interfering with the interlocking forks of the assembled extension tube mechanism.

The heads of the clamping pivotal centre bolt passing through aperture 6 can be countersunk in a similar way for neatness.

(ii) Seat extension tube mechanism Referring now to figures 3-6, an extension tube is shown suitable for use with a seat figure 5 shows an upper elongate tube member 11 with an elongate central pivotal bolt hole 12 (same function as in handlebar extension). One end is arranged to receive a seat, as in the prior art. The other is bifurcated to form two forks 13 having toothed engagement members 14 extending around at least one quarter of the end radius of the forks 13. This extent could be increased as in the handlebar mechanism described above.

The tull adjustment range as shown is 45 degrees either side of the vertical. As with the handlebar extension the two radius toothed ended forks 13 of the upper elongated member are designed to slot into the three radius toothed ended forks 15 of the lower elongated member 16 shown in figure 4. The teeth of 16 are linearly arranged across on the shoulder 17 between the forks of member 16, and are designed to synchronise with the toothed engagement members 14.

The lower extension tube member is clamped into the seat tube in the normal way.

Finally the seat extension tube mechanism is designed to be adjusted in exactly the same manner as the handlebar extension tube mechanism

Claims

Claims 1. An adjustable extension arrangement suitable for use with a pedal cycle seat or handlebars, comprising: a first elongate member having at a first end thereof one or more engagement means; a second elongate member having at a first end thereof one or more receiving means for receiving said engagement means to operatively inhibit longitudinal angular movement between said first and second members; and retaining means for inhibiting longitudinal separation of said first and second members.
2. An arrangement as claimed in claim 1, wherein said engagement means comprises a plurality of engagement dedents and said receiving means comprises one or more corresponding indents.
3. An arrangement as claimed in claim 2, wherein said engagement means comprises a disc having a plurality of teeth around an exterior circumference thereof, and said receiving means comprises a plurality of corresponding receiving teeth.
4. An arrangement as claimed in any preceding claim, wherein said first end of said first member is bifurcated for receiving said first end of said second member there between or vice versa.
5. An arrangement as claimed in claim 1, wherein; said first end of said first member is divided into one or more discs having engagement teeth around a circumference thereof; said first end of said second member is provided with a corresponding one or more slots for receiving said discs, an interior surface of said slots having one or more toothed receiving apertures for operatively receiving and interlocking with said engagement teeth; said first end of said first member and said first end of said second member having a lateral aperture there through for receiving said retaining means comprising a lateral clamping means.
6. An arrangement as claimed in claim 5, wherein said aperture is elongate to allow longitudinal separation of said first and second members and thereby disengage said engagement means and said receiving means, without requiring complete removal of said clamping means.
7. An arrangement as claimed in any preceding claim, wherein a second end of said first member is provided with means for receiving a cycle seat or a cycle handlebars, and a second end of said second member is arranged to be coupleable to a frame of a pedal cycle, or vice versa.
8. An arrangement substantially as hereinbefore described with reference to the accompanying drawings.