WO1981003003A1

WO1981003003A1 - A gear

Info

Publication number: WO1981003003A1
Application number: PCT/DK1981/000036
Authority: WO
Inventors: J Lauesen
Original assignee: J Lauesen
Priority date: 1980-04-14
Filing date: 1981-04-14
Publication date: 1981-10-29
Also published as: EP0050141A1

Abstract

External chain-shifting gears have a large building width, which necessitates the application of unsymmetrical rear wheels. In order to avoid this a number of toothed rims (1) is embedded with axial displacement on a guiding barrel (4) with side flanges (5). The toothed rims (1) have pins (2), which through slits (3) in the guiding barrel (5) are in mesh with helical grooves (7) in a sleeve (6) embedded inside the guiding barrel (4). A gear changing mechanism rotates the sleeve (6) in relation to the guiding barrel (4), by which means the toothed rims (1) are led from a position of rest at the side flange (5) of the guiding barrel (4) to the middle of the guiding barrel (4).

Description

A GEAR.

The present invention relates to a gear, especially for bicycles, of the kind in which a pulling chain or tooth belt can be changed between a number of toothed rims of different diameter and number of teeth by means of a chain guide and a chain tightener.

External chain-shifting gears (derailleur gears) have a number of toothed rims on the rear axle. The bicycle can by means of a chain guide and a chain tightener change from one toothed rim to another. Hereby the chain is generally exposed to a wrong pull, as only one of the toothed rims can be lying on the same level as the crank blade of the bicycle.

The object of the invention is to provide a gear which permits the chain to remain on the same level, which has a lower weight than known gears, which is compact and sturdy, which provides an exact gear shifting, which is simple to repair, and which, contrary to hub gears, can be individually adjusted to bicycles.

This object is obtained by embedding the toothed rims with axial displacement and by adapting a gear changing mechanism for carrying out this displacement.

Hereby is obtained that waste and chain wear is reduced and that it is possible to use a symmetric rear-wheel which is considerably more stable than the generally used rear-wheels in connection with derailleurgears.

The gear can according to claim 2 be characterized in that a number of toothed rims by means of pins is embedded in a guiding barrel with axial slits and side flanges. By these means a compact gear is obtained, as the toothed rims, which are not in mesh with the chain or the tooth belt, are packed up at the side flanges of the guiding barrel so that only the toothed rim, which is in mesh, is free.

The gear can according to claim 3 be characterized in that a number of toothed rims by means of round or long holes is embedded on a guiding barrel which consists of two end flanges and a number of round-going stay bolts. This embodiment is insensitive to mud.

The gear can according to claim 4 be characterized in that the gear changing mechanism consists of a sleeve, which is placed coaxially inside the guiding barrel, and which has helical grooves in which the turning-in pins of the toothed rims are in mesh, and that the gear changing mechanism is activated by a braking of the sleeve and at the same time a forward or backward movement of the pulling chain. This embodiment is simple and inexpensive.

The gear can according to claim 5 be characterized in that the gear changing mechanism consists of axially sliding bolts adapted for moving the toothed rims in axial direction. This embodiment is sturdy and provides an exact gear shifting.

The gear can according to claim 6 be characterized in that a number of toothed rims is embedded with equidistant intervals on a sleeve with axial dis placement, that the gear changing mechanism consists of a besides generally known shifter fork, and that the toothed rims can be locked by means of a ball catch or the like. This embodiment is simple and very inexpensive to produce, at the same time as the gear fulfils the requirements of most cyclists as the toothed rims in a simple way can be individually adjusted.

The gear can according to claim 7 be characterized in that the chain tightener permits the application of a back-pedal brake as it, when the chain is moving in the opposite direction, holds this in a tight position to such an extent that the braking operation is neither delayed nor reduced. Hereby a considerable inconvenience is eliminated, which is known from generally known derailleur gears in which the chain is not all the time lying on the same level.

The invention is further elucidated with reference to the drawing in which

Fig. 1 shows components for a gear according to the invention seen in perspective; Fig. 2 a sectional view through a gear which consists of the single components in fig. 1, and Pig. 3 components for the other embodiment of the gear seen in perspective.

A gear according to the invention is shown separated in fig. 1, only the essential components being shown. A toothed rim 1 has three internal pins 2,which can be thrown into mesh with corresponding slits 3 in a guiding barrel 4, which is provided with side flang es 5. A sleeve 6 with three helical grooves 7 corresponding to the three pins 2 in the toothed rim 1 is placed coaxially inside the guiding barrel. Fig. 2 shows a cross section view of these three components 1, 4, and 6 in an assembled condition.

By a relative rotation of the sleeve 6 in relation to the guiding barrel 4 the toothed rim will be displaced towards one of the side flanges 5 dependent on the direction of this rotation. At the same time another, not shown, toothed rim will be led from the other side flange 5 towards the middle of the guiding barrel 4 where the pulling chain will be twisted on the toothed rim gradually as the chain is twisting off the first toothed rim 1. The guidance of the chain takes place by means of a general chain guide and a chain tightener, which in this way only has to move on one level.

Fig. 3 shows another embodiment of the gear, in which a guiding barrel 11 consists of two end flanges 12, which are held together by a number of stay bolts 13. Toothed rims 8 provided with round or long holes

9 are embedded on the guiding barrel 11. The toothed rims 8 have like the toothed rims 1 turning-in pins

10 to be thrown into mesh with the grooves 7 in the sleeve 6.

In the shown and described embodiment of the gear the toothed rims are mounted on the rear axle. However, toothed rims can also be mounted on the pedal axle, which can be axially displaced. The chain is guided by a steering fork, and the gear shifting takes place by an axial displacement of the pedal axle .

The invention is not confined to a bicycle gear, as the gear can be used for many other purposes, where general gear constructions are used today. Thus it is obtained that the gear shifting can take place without using a clutch and that the transmission takes place with less waste, since indirect gears are avoided. Besides the gear can be independently placed either on the pulling or on the pulled axle. Furthermore, in the embodiments described the sleeve and the guiding barrel can be interchanged, as the grooves in the sleeve can be changed into through-going slits.

Claims

C L A I M S

1. A gear, especially for bicycles, of the kind in which a pulling chain or tooth belt can be changed between a number of toothed rims of different diameter and number of teeth by means of a chain guide and a chain tightener, c h a r a c t e r i z e d i n that the toothed rims (1, 8) are embedded with axial displacement, and that a gear changing mechanism is adapted for the carrying out of this displacement.

2. A gear according to claim 1, c h a r a c t e r i z e d i n that a number of toothed rims (1) by means of pins (2) is embedded in a guiding barrel (4) with axial slits (3) and side flanges (5).

3. A gear according to claim 1, c h a r a c t e r i z e d i n that a number of toothed rims (8) by means of round or long holes (9) is embedded on a guiding barrel (11) which consists of two end flanges (12) and a number of round-going stay bolts (13).

4. A gear according to claim 2 or 3, c h a r a c te r i z e d i n that the gear changing mechanism consists of a sleeve (6), which is coaxially placed inside the guiding barrel (4, 11), and which has helical grooves (7), in which the turning-in pins (2, 10) of the toothed rims (1, 8) are in mesh, and that the gear changing mechanism is activated by a braking of the sleeve (6) and at the same time a forward or backward movement of the pulling chain.

5. A gear according to claim 2 or 3, c h a r a c t e r i z e d i n that the gear changing mechanism consists of axially sliding bolts adapted for moving the toothed rims (1, 8) in axial direction.

β. A gear according to claim 1, c h a r a c t e r i z e d i n that a number of toothed rims is embedded with equidistant intervals on a sleeve with axial displacement, that the gear changing mechanism consists of a,besides generally known, shifter fork, and that toothed rims can be locked by means of a ball catch or the like.

7. A gear according to each of claims 1 - 6, c h a r a c t e r i z e d i n that the chain tightener permits the application of a back-pedal brake, as it, when the chain is moving in the opposite direction, holds this in a tightened position to such an extent that the braking operation is neither delayed nor reduced.