GB2344324A

GB2344324A - Pedal cycle sub-frame

Info

Publication number: GB2344324A
Application number: GB9928727A
Authority: GB
Inventors: Michael Alan Brigden
Original assignee: Individual
Current assignee: Individual
Priority date: 1998-12-05
Filing date: 1999-12-06
Publication date: 2000-06-07
Anticipated expiration: 2019-12-06
Also published as: GB2344324B; AU1667000A; GB9826734D0; GB9928727D0; WO2000034113A1

Abstract

The subframe (10) is integrally fixed to or demountably attachable to a cycle frame without (a) rear wheel(s); the subframe(10) is adapted to carry a load and is provided with a means to house a wheel or wheels whereby the wheel base of the conventional cycle is extended. The subframe (10) can be attached to the cycle frame by means of a V-frame bar (30), which may comprise adjustable arms to accommodate cycles frames of different sizes. The sub-frame (10) can form an enclosed carrier and may support a motor for applying power to the rear wheel.

Description

A MODIFIED CYCLE FRAME Field of the Invention The present invention relates to bicycle frames and more particularly to a bicycle frame modified to increase the load bearing capacity of a bicycle Background to the Invention Although cycles are constantly improving due to better design of the components and the use of new materials, they still suffer from two basic drawbacks. The first is their limited load bearing capacity. The second is their limited energy available for motive power since that energy comes primarily from the rider.

Summary of the Invention According to a first aspect of the invention, there is provided a subframe for use with a conventional cycle, the subframe (10) being demountably attachable in use to the frame of the conventional cycle of which the or each rear wheel has been removed, wherein the subframe (10) is adapted to carry a load and comprises connection means for one or more rear wheels whereby the wheel base of the conventional cycle is extended The said wheel or wheels may comprise the wheel (s) of the conventional cycle but alternatively or additionally may include a further wheel or further wheels.

The subframe is preferably attached to the frame of a conventional cycle by a V- frame bar.

The V-frame bar preferably comprises arms which are adjustable in length to accommodate different size conventional main frames.

The subframe preferably comprises handles by which the subframe may be lifted.

According to a second aspect of the invention there is provided a cycle frame, for a solo rider, in which a subframe extends rear vardly from the rider's seat to hold, in use, a rear wheel or wheels, the subframe being so sized and shaped as to bear or otherwise carry a load between the front and the or each rearmost wheel, the subframe thereby extending the wheelbase of the cycle by comparison with that of a conventionat soto cycle frame, characterised in that the subframe forms an integral non-demountable part of the cycle frame and in that the subframe does not nor is intended in use to carry the chainset and pedals for propelling the cycle The cycle frame advantageously comprises a tensioning guide, other than the conventional rear wheel derailleur gear chain-tensioning arm to prevent the cycle chain from dragging on the ground in use.

The cycle frame is preferably adapted to operate with two chains, engaging sprockets mounted about a common spindle, the spindle being located between the pedals and the rear wheel.

Brief Description of the Drainas Figure 1 is a perspective view of a subframe embodying the first aspect of the invention ; Figure 2 is a plan view of a'V'-frame bar attaching the subframe to the main frame chassis ; Figure 3 shows it in side view; Figure 3a is a plan view of a v-frame bar having adjustable length side arms, for attaching the subframe to the main frame chassis, Figure 3b shows it in side view ; Figure 4 is a side view partly in cross-section of a bicycle embodying a second aspect of the invention ; Figure 5 is an enlarged plan view of the spindle and hub connecting the main frame chassis to the subframe; Figure 5a is an enlarged plan view of a further example of spindle and hub connecting the main frame chassis to the subframe ; Figure 6 is a plan view (showing the wheel in cross-section) of a motor driven wheel.

Figure 7 is a side view of a subframe having handles ; and Figure 8 shows it in plan view.

Description of the Preferred Embodiments Referring to Figure 1, the bicycle extending subframe 10 comprises a tube 11, bent into an almost complete rectangle, the two ends 12 of the tube 11 defining a gap in the rectangle through which, in use, the rear wheel will pass. Tube 111 in this manner forms the base of the subframe 10, with the gap, in use. being at the rear of the subframe 10. The ends of tube I I are sealed. Four further steel tubes 13 are welded to the tube 11 along the long edge of the rectangle, and orientated upward, substantially right angles to the plane of the rectangle a short way in from each corner. A steel tube 14 is welded to the tube 11 along the upper plane of the rectangle and tubes parallel to its long sides. One point of contact between tube 14 and tube 11 is above the free end of tube 11. A further steel tube 1 is similarly positioned and fixed above the other free end of tube 11. The tubes 14 and 15 are also of such a length that they project beyond both edges of the rectangular base. A further steel'tube 16, has one of its ends welded to tube 14, above the position where tube 14 is itself welded to tube 11. Tube 16 is orientated generally perpendicular to the plane of the rectangular base, tube 17 is similarly attached to tube 15. A rectangular frame 18 of slightly longer length than the base and also formed from steel tubes is welded onto the free ends of each of 13. 16 and 17. Supporting struts 19 and 20 connect the outside of tube 14 to tube 16. and tube 15 to tube 17 respectively.

At both ends of each of tubes 16 and 17 is a dropout 21 A-D which in use locates the subframe 10 on the spindle of the rear wheel, 64 of a bicycle-or"pushbike"- and also to the main frame of a bicycle, or a spindle, thus allowing the subframe to be secured.

The subframe 10, shown in Figure 1, is secured to the mainframe by means of a 'V'frame 30 shown in Figs 2 and 3. Referring firstly to Fig 2, frame clamps 31 fit around rectangular frame 18 of subframe 10. Frame bar 32 is then fixed at a first end to clamp 31 In fig 3, a seat pillar clamp'ils fitted around the seat pillar 34, (shown in cross-section) and the second end of the frame bar 32, secured to it.

The type of fitting described here is adjustable enough to allow the subframe 10 to be fitted to main frames of different sizes Alternatively, or in addition to beina adjustable, the fitting may also be flexible. Figure 4 shows the subframe attached, in part via'V'shaped clamp 30, to the main frame of a bicycle.

Figures 3a and b show an example of an adjustable V-frame. The sub frame 18 comprises two lugs 35 A, B integrally fixed to a bar of the sub frame and spaced apart from one another, each lug having an aperture whose axis is parallel to that of the bar. Each arm of the V-frame is in two sections. Section 36A is fixed at a first end to lug 35A. Section 37A is secured at a first end to the seat pillar clamp 33, which itself is secured to the seat pillar of the bicycle. The two sections are threadably connected together to form the arm. The use of a threadable connection allows the length of the frame arm to be adjusted so that different sizes of bicycle main frame can be accommodated. Once the section bar has been adjusted to a suitable length tightening of the locking nuts 38 fixes the relative positions of sections 36A and 37A.

To attach the subframe 10, the rear wheel of the bicycle is removed and reattached to the dropouts 2IA and B at the rear of the subframe 10, the rim of the wheel passing through the space between tubes 16 and 17 and the gap defined by the end of the tube 11. The dropouts 21 C and D at the front of the subframe 10 are passed over spindle 50 (see Fig 5 described below) the spindle fitting into the rear wheel dropouts 41 of the main frame. The original chain 42 of the bicycle fits over sprocket 51 on spindle 50. A further chain 43 links the sprocket 52 and hence spindle 50, to the sprockets 44 on the rear wheel.

In Fig 5 a hub 53 is fixedly mounted about a rear wheel spindle 50, fixed wheel sprockets 5 1 and 52 are also fixedly mounted about the spindle, separated by spacer, 54 from the hub 53. Dropouts 21C and D fit around the rear wheel spindle 50, and are separated from the hub 53 and sprockets 51, and 52 by further spacers.

Main frame dropouts 55 A and B fit around the spindle 50 and are separated from the dropouts 21C and D by further spacers 54.

Figure 5a illustrates the dropouts of the subframe fitted to the rear wheel on a bicycle having struck its suitable 4,5 or 10 gears. In this Figure the dropouts 21 c, d are shown to be fitted to the spindle 57 without the need of spacers to separate them from the other components on the spindle.

The frame can particularly be used to bear loads such as shopping, sports equipment etc. Alternatively, and additionally it can bear a motor and power source for the motor. The motor when connected to one or more of the wheels, can be used to provide motive force for the pushbike, either alone or in cooperation with that provided through the rider pedalling. Power for the motor can be provided from a battery or batteries for example, conventional storaoe batteries, such as gel batteries. Alternatively, a part or all of the power can come from solar panels.

Fig 6 illustrates one way in which a motor could be used to propel the bicycle Rear wheel tire 60, mounted about rim 61, is in contact with carborundum roller 62. The motor 63, is actuated and controlled by the rider of the bicycle, and upon actuation, causes the roller 62 to rotate, which in turn causes, via the contact between the tire 60 and roller 62, the rear wheel 64 to rotate and hence the bicycle to move. Power for the motor 63 comes from batteries 65.

The material from which the subframe is constructed will need to be both rigid and durable, and as well as being formed from steel, could also be formed from plastic. Although, the tubes are shown above as being welded together, they could also be fixed and held together by nuts and bolts, or screws This won ! d both allow replacement parts to be added easily, as well as for the frame to be dismantled and more conveniently stored when not required.

As alternatives to tubes, struts, bars or laths could also be used. The frame could also be made so that the walls are continuous and hence form a container. The container could also incorporate a frame as illustrated above. The watts of the container form from, for example a moulded plastic or fibre-glass, are formed around and include the frame, the frame then acting to provide support for the container body. Alternatively, a separate container could be added, suitaby contoured to avoid the rear wheel or wheels The container, whether formed from the frame or added separately, can be covered over to give watertight compartment, and can also be adapted to fit a child seat.

Figures 7 and 8 illustrate a subframe 70 having handles 71 and 72 by which the subframe may be lifted and/or carried. The handles as shown also provide additional protection for the load being carried in the event of side impact. This is particularly important when the bicycle is being used to transport a child The'V'frame acts to aid dissipation of downwards forces from the rider and the load, firstly in a horizontal direction and the, through the frame, to the rear wheel or wheels.

It can, if necessary, be replaced by a spring and damper mechanism. Both the frame and a spring and damper mechanism will also impart suspension to the rider and load.

It can be envisage that energy derived from a solar panel could both power the motor and charge up any batteries present. An alternative to an electrically powered motor is to use one powered by compressed air, in which case housin2 for the cylinders can be provided within or attached to the frame. The motor can be connected to the hub of either wheel in order to drive it. In an alternative embodiment (not illustrated) the motor and connection to the wheel could be placed outside the subframe, preferably beneath it This woufd allow any box or container to be made more watertight as there"-olild not need to be a hole in to connect for example, referring to Fig 6, the roller 62 to the bore, 60.

For the sake of clarity, although the subframe is shown in the Figures as being separable from the main chassis of a conventional bicycle, this should not be taken as limiting, and pushbikes wherein the subframe is permanence fixed are also within the scope of the invention.

It will of course be understood that the invention is not limited to the specific details described herein, which are shown by way of example on) y, and that various modifications and alterations are possible within the scope of the appended claims.

Claims

CLAIMS 1. A subframe for use with a conventional cycle, the subframe being demountably attachable to the frame of the conventiona ! cyde from which the or each rear wheel has been removed, wherein the subframe N adapted to carry a load and comprises connection means for one or more rear wheels whereby the wheel base of the conventional cycle is extended.
2. A subframe according to Claim 1, wherein the or each wheel comprises the or each wheel removed from the conventional cycle.
3. A subframe according to Claim 1 or Claim 2, wherein the subframe is attached to the frame of the conventional cycle by a V-frame bar
4. A subframe according to Claim 3, wherein the V-frame bar comprises arms which are adjustable in len to accommodate different size conventional main frames.
5. A subframe according to any one of the preceding Claims, wherein the subframe comprises handles by which the subframe may be lifted.
6. A subframe substantially as herein described with reference to and as illustrated by any appropriate combination of the accompanying drawings
7. A cycle frame, for a solo rider, in which a subframe extends rearwardl ! from the rider's seat to hold, in use, a rear wheel or wheels, the subframe being so sized and shaped as to bear or otherwise carry a load between the front and the or each rearmost wheel, the subframe thereby extending the wheelbase of the cycle by comparison with that of a conventional solo cycle frame, characterised in that the subframe forms an integral non demountable part of the cycle frame and in that the subframe does not nor is intended in use to carry the chainset and pedals for propellinY the cycle.
8. A cycle frame according to Claim 7 wherein the cycle frame further comprises a tensioning guide, other than the conventional rear wheel derailleur gear chain-tensioning arm.
9. A cycle frame according to either of Claims 7 or 8 wherein the frame is adapted to operate with two chains, engaging sprockets mounted about a common spindle, the spindle being located between the pedals and the rear wheel.