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WO1992013752A1 - Improvement relating to bicycles - Google Patents

Improvement relating to bicycles Download PDF

Info

Publication number
WO1992013752A1
WO1992013752A1 PCT/GB1992/000250 GB9200250W WO9213752A1 WO 1992013752 A1 WO1992013752 A1 WO 1992013752A1 GB 9200250 W GB9200250 W GB 9200250W WO 9213752 A1 WO9213752 A1 WO 9213752A1
Authority
WO
WIPO (PCT)
Prior art keywords
bicycle
axle
chainring
shaft
pinion wheel
Prior art date
Application number
PCT/GB1992/000250
Other languages
French (fr)
Inventor
Malachy Gérard O'BOYLE
Original Assignee
Boyle Malachy Gerard O
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Priority claimed from GB919102942A external-priority patent/GB9102942D0/en
Priority claimed from GB919112976A external-priority patent/GB9112976D0/en
Application filed by Boyle Malachy Gerard O filed Critical Boyle Malachy Gerard O
Publication of WO1992013752A1 publication Critical patent/WO1992013752A1/en

Links

Classifications

    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B62—LAND VEHICLES FOR TRAVELLING OTHERWISE THAN ON RAILS
    • B62M—RIDER PROPULSION OF WHEELED VEHICLES OR SLEDGES; POWERED PROPULSION OF SLEDGES OR SINGLE-TRACK CYCLES; TRANSMISSIONS SPECIALLY ADAPTED FOR SUCH VEHICLES
    • B62M9/00—Transmissions characterised by use of an endless chain, belt, or the like
    • B62M9/04—Transmissions characterised by use of an endless chain, belt, or the like of changeable ratio
    • B62M9/06—Transmissions characterised by use of an endless chain, belt, or the like of changeable ratio using a single chain, belt, or the like
    • B62M9/10—Transmissions characterised by use of an endless chain, belt, or the like of changeable ratio using a single chain, belt, or the like involving different-sized wheels, e.g. rear sprocket chain wheels selectively engaged by the chain, belt, or the like
    • B62M9/14—Transmissions characterised by use of an endless chain, belt, or the like of changeable ratio using a single chain, belt, or the like involving different-sized wheels, e.g. rear sprocket chain wheels selectively engaged by the chain, belt, or the like the wheels being laterally shiftable

Definitions

  • This invention relates to improvements relating to bicycles which for the purposes of this invention includes a frame having front and rear downwardly converging struts rooted to a bottom tubular bracket through bearings in which an axle is journalled to extend therebeyond carrying rotationally fast a front chainring near to one end thereof with opposite ends of the axle carrying a crank mounting a pedal.
  • the frame has a rearward fork extending from the bracket, the limbs of which are similarly splayed apart and at the distal ends of which are provided mountings between which is carried a shaft on which the rear wheel is mounted. The rear wheel rotates through the fork.
  • the shaft carries near its outer end, corresponding to the same lateral side as the front chainring is mounted on the axle, an arrangement of rear sprockets of a gearing system.
  • a chain is entrained around the chainring or a front sprocket thereon and one or other rear sprocket.
  • the chainring is aligned with one sprocket but not with the other sprockets therefore when the chain is around any one of the other sprockets, the chain, chainring and sprocket are not in alignment with the consequential possibility that friction is caused between the links of the chain.
  • Ther is power wastage and there is the possibility of the chain disengaging from the chainring or the sprocket.
  • This problem is particularly, but not necessarily, applicable to bicycles, normally referred to as mountai bicycles or to racing bicycles, in the use of which the maximum travelling speed is required from the effort pu into the pedalling action.
  • An object of the present invention is to obviate or mitigate the problem described above.
  • the present invention is a bicycle of the type aforesaid in which the axle is of extended length and a mechanism is provided connected to the axle to allow for lateral shift of the axle with change of gear selection to reposition the front chainring to maintain it in alignment with the sprocket selected in use on the back wheel.
  • a mechanism is preferably provided for connection to an extended axle to allow for lateral shift of the axle with change of gear selection to reposition the front chainring to maintain it in alignment with the sprocket selected in use on the back wheel.
  • the mechanism comprises a unit secure to one of the struts, the unit having a housing with a tubular passage whose axis is parallel to that of the bracket and through which a shaft is in sliding relationship.
  • the shaft intermediate its ends, preferably has opposite upper and lower surfaces, the upper surface being toothed to form a rack and the lower surface having a row of indentations.
  • the housing desirably encases a low friction rotatable toothed member whose teeth mesh with the teeth of the rack.
  • the toothed member is preferably a pinion wheel and has desirably a coaxial extension around which a helical groove is provided.
  • a cable is preferably provided around the groove and anchored thereto, the ends of the cable passing out through a respective upright passage to be anchored to lever, arcuate movement of which controlling rotational movement of the pinion wheel and therefore of longitudinal movement of shaft.
  • the ends of the cable are anchored to a lever of the gear change mechanism whereby alteration of the gear synchronously alters the position of the chainring on the axle.
  • the or each end of the shaft is tied to the axle by a link, the or each link having a bearing which permits only rotational movement of the axle.
  • the limb of the fork on the side on which the chain is positioned is shaped to avoid interference with movement of the chain with sliding adjustment of the axle and chainring.
  • Fig. 1 is a perspective view of part of a bicycle according to the present invention.
  • Fig. 2 is a perspective view of a mechanism mounted on a bicycle to a larger scale
  • Fig. 3 is a vertical cross-section of a housing of the mechanism
  • Fig. 4 is a plan view of part of a bicycle frame showing the forks on which is mounted the rear wheel;
  • Fig. 5 is side elevational view of a pinion wheel of the mechanism.
  • Fig. 6 is a plan view of a modified toothed member.
  • a bicycle of the type aforesaid having the axle 10 of extended length and a mechanism connected to the axle 10 to allow for lateral shift of the axle 10 with change of gear selection to reposition the front chainring 12 to maintain it in alignment with the sprocket 14 selected in use on the back wheel 8.
  • the mechanism comprises a unit 16 secured to the rear strut 18 by clamp rings 20.
  • the unit 16 has a housing 22 with a tubular passage 24 whose axis is parallel to that of the bracket 26 and through which a shaft 28 is in sliding relationship.
  • the shaft 28, intermediate its ends, has opposite upper and lower planar surfaces.
  • the upper surface is toothed to form a rack 30 and the lower surface has a row of indentations 32.
  • the housing 22 encases a low friction rotatable toothed member, in this embodiment, a pinion wheel 34 whose teeth mesh with the teeth of the rack 30.
  • the pinion wheel 34 has a coaxial extension 36 around which a helical groove 38 is provided.
  • the teeth of the shaft 28 are held in engagement with the teeth of the rack 30 at their point of contact by two spring-biased ball bearings 42 engaging in respective indentations 32, the ball bearings 42 being spaced apart a corresponding distance or multiple thereof as the spacings between the indentations 32 as shown.
  • the springs 44 of the spring- biasing are housed in respective bores 46 at right angles to the passage 24.
  • the springs 44 are held in place by grub screws 48 in threaded engagement with screw threads at the outer ends of the bores 46.
  • a cable 40 is provided around the groove 38 and anchored thereto.
  • the ends of the cable 40 passing out through a respective upright passage 50 to be anchored to a lever 51 , arcuate movement of which controlling rotational movement of the pinion wheel 34 and therefore of longitudinal movement of the shaft 28.
  • Each end of the shaft 28 is tied to the axle 10 by a link 52.
  • Each link 52 has a race bearing 54 which permits only rotational (and not axial) movement of the axle 10 therein.
  • the limb 56 of the fork 58 on the side on which the chain 57 is positioned is shaped to avoid interference with movement of the chain 57 with sliding adjustment of the axle 10 and chainring 12.
  • the lever 51 for the mechanism is moved to correspondingly move the chainring 12 along the shaft 28 to bring the chainring 12 or a first sprocket thereon, the chain and a rear sprocket (shown generally at 60 Fig. 3) into alignment.
  • the mechanism can be screwed to the front street and the ends of the cable 40 are anchored to the lever 59 of the gear change mechanism whereby alteration of the gear synchronously alters the position of the chainring 12 on the axle 10, lever 51 is therefore dispensed with.
  • a modified toothed member is used, namely a segment pinion wheel 35 as shown in Fig. 6, and a circumferential groove 37 to seat cable 40 is provided mid-way through the teeth of the segmental pinion wheel 35.

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  • Engineering & Computer Science (AREA)
  • Chemical & Material Sciences (AREA)
  • Combustion & Propulsion (AREA)
  • Transportation (AREA)
  • Mechanical Engineering (AREA)
  • Transmission Devices (AREA)

Abstract

A bicycle of the type aforesaid has an axle (10) of extended length. A mechanism is provided connected to the axle (10) to allow for lateral shift of the axle (10) with change of gear selection to reposition the front chainring (12) to maintain it in alignment with the sproket (14) selected in use on the back wheel (8). The mechanism comprises a unit (16) secured to one of the struts (18). The unit (16) has a housing (22) with a tubular passage (24) whose axis is parallel to that of the bracket (26) and through which a shaft (28) is in sliding relationship.

Description

IMPROVEMENT RELATING TO BICYCLES.
This invention relates to improvements relating to bicycles which for the purposes of this invention includes a frame having front and rear downwardly converging struts rooted to a bottom tubular bracket through bearings in which an axle is journalled to extend therebeyond carrying rotationally fast a front chainring near to one end thereof with opposite ends of the axle carrying a crank mounting a pedal. The frame has a rearward fork extending from the bracket, the limbs of which are similarly splayed apart and at the distal ends of which are provided mountings between which is carried a shaft on which the rear wheel is mounted. The rear wheel rotates through the fork. The shaft carries near its outer end, corresponding to the same lateral side as the front chainring is mounted on the axle, an arrangement of rear sprockets of a gearing system. A chain is entrained around the chainring or a front sprocket thereon and one or other rear sprocket. Hereinafter in the specification and claims a bicycle described above will be referred to as "a bicycle of the type aforesaid".
A problem exists with conventional chainring/ sprocket relationships in that the chainring is fixed on the axle which is axially fast. The chainring is aligned with one sprocket but not with the other sprockets therefore when the chain is around any one of the other sprockets, the chain, chainring and sprocket are not in alignment with the consequential possibility that friction is caused between the links of the chain. Ther is power wastage and there is the possibility of the chain disengaging from the chainring or the sprocket. This problem is particularly, but not necessarily, applicable to bicycles, normally referred to as mountai bicycles or to racing bicycles, in the use of which the maximum travelling speed is required from the effort pu into the pedalling action.
An object of the present invention is to obviate or mitigate the problem described above.
Accordingly, the present invention is a bicycle of the type aforesaid in which the axle is of extended length and a mechanism is provided connected to the axle to allow for lateral shift of the axle with change of gear selection to reposition the front chainring to maintain it in alignment with the sprocket selected in use on the back wheel.
In or for a bicycle of the type aforesaid, a mechanism is preferably provided for connection to an extended axle to allow for lateral shift of the axle with change of gear selection to reposition the front chainring to maintain it in alignment with the sprocket selected in use on the back wheel.
Preferably, the mechanism comprises a unit secure to one of the struts, the unit having a housing with a tubular passage whose axis is parallel to that of the bracket and through which a shaft is in sliding relationship. The shaft, intermediate its ends, preferably has opposite upper and lower surfaces, the upper surface being toothed to form a rack and the lower surface having a row of indentations. The housing desirably encases a low friction rotatable toothed member whose teeth mesh with the teeth of the rack. The toothed member is preferably a pinion wheel and has desirably a coaxial extension around which a helical groove is provided.
A cable is preferably provided around the groove and anchored thereto, the ends of the cable passing out through a respective upright passage to be anchored to lever, arcuate movement of which controlling rotational movement of the pinion wheel and therefore of longitudinal movement of shaft. Alternatively, the ends of the cable are anchored to a lever of the gear change mechanism whereby alteration of the gear synchronously alters the position of the chainring on the axle.
Preferably also, the or each end of the shaft is tied to the axle by a link, the or each link having a bearing which permits only rotational movement of the axle. Preferably further, the limb of the fork on the side on which the chain is positioned is shaped to avoid interference with movement of the chain with sliding adjustment of the axle and chainring.
An embodiment of the present invention will now be described, by way of example, with reference to the accompanying drawings, in which:-
Fig. 1 is a perspective view of part of a bicycle according to the present invention;
Fig. 2 is a perspective view of a mechanism mounted on a bicycle to a larger scale;
Fig. 3 is a vertical cross-section of a housing of the mechanism;
Fig. 4 is a plan view of part of a bicycle frame showing the forks on which is mounted the rear wheel;
Fig. 5 is side elevational view of a pinion wheel of the mechanism; and
Fig. 6 is a plan view of a modified toothed member.
Referring to the drawings, a bicycle of the type aforesaid is provided having the axle 10 of extended length and a mechanism connected to the axle 10 to allow for lateral shift of the axle 10 with change of gear selection to reposition the front chainring 12 to maintain it in alignment with the sprocket 14 selected in use on the back wheel 8. The mechanism comprises a unit 16 secured to the rear strut 18 by clamp rings 20. The unit 16 has a housing 22 with a tubular passage 24 whose axis is parallel to that of the bracket 26 and through which a shaft 28 is in sliding relationship. The shaft 28, intermediate its ends, has opposite upper and lower planar surfaces. The upper surface is toothed to form a rack 30 and the lower surface has a row of indentations 32. The housing 22 encases a low friction rotatable toothed member, in this embodiment, a pinion wheel 34 whose teeth mesh with the teeth of the rack 30. The pinion wheel 34 has a coaxial extension 36 around which a helical groove 38 is provided. The teeth of the shaft 28 are held in engagement with the teeth of the rack 30 at their point of contact by two spring-biased ball bearings 42 engaging in respective indentations 32, the ball bearings 42 being spaced apart a corresponding distance or multiple thereof as the spacings between the indentations 32 as shown. The springs 44 of the spring- biasing are housed in respective bores 46 at right angles to the passage 24. The springs 44 are held in place by grub screws 48 in threaded engagement with screw threads at the outer ends of the bores 46.
A cable 40 is provided around the groove 38 and anchored thereto. The ends of the cable 40 passing out through a respective upright passage 50 to be anchored to a lever 51 , arcuate movement of which controlling rotational movement of the pinion wheel 34 and therefore of longitudinal movement of the shaft 28.
Each end of the shaft 28 is tied to the axle 10 by a link 52. Each link 52 has a race bearing 54 which permits only rotational (and not axial) movement of the axle 10 therein.
The limb 56 of the fork 58 on the side on which the chain 57 is positioned is shaped to avoid interference with movement of the chain 57 with sliding adjustment of the axle 10 and chainring 12.
In use, when the bicycle is in use and the gear selection is changed using a lever 59, the lever 51 for the mechanism is moved to correspondingly move the chainring 12 along the shaft 28 to bring the chainring 12 or a first sprocket thereon, the chain and a rear sprocket (shown generally at 60 Fig. 3) into alignment.
In a first modification, (the mechanism can be screwed to the front street and the ends of the cable 40 are anchored to the lever 59 of the gear change mechanism whereby alteration of the gear synchronously alters the position of the chainring 12 on the axle 10, lever 51 is therefore dispensed with.
In a second modification, a modified toothed member is used, namely a segment pinion wheel 35 as shown in Fig. 6, and a circumferential groove 37 to seat cable 40 is provided mid-way through the teeth of the segmental pinion wheel 35.
In a third modification, only one end of each e of the sha t 28 is tied to the axle 10 through a link 52.
Variations and other modifications can be made without departing from the scope of the invention as claimed.

Claims

1. A bicycle of the type aforesaid in which the axle is of extended length and a mechanism is provided connected to the axle to allow for lateral shift of the axle with change of gear selection to reposition the front chainring to maintain it in alignment with the sprocket selected in use on the back wheel.
2. In or for a bicycle of the type aforesaid, a mechanism is provided for connection to an extended axle to allow for lateral shift of the axle with change of gear selection to reposition the front chainring to maintain it in alignment with the sprocket selected in use on the back wheel.
3. A bicycle as claimed in Claim 1 or 2, wherein the mechanism comprises a unit secured to one of the struts, the unit having a housing with a tubular passage whose axis is parallel to that of the bracket and through which a shaft is in sliding relationship.
4. A bicycle as claimed in Claim 3, wherein the shaft, intermediate its ends, has opposite upper and lower surfaces, the upper surface being toothed to form a rack and the lower surface having a row of indentations.
5. A bicycle as claimed in Claim 3 or 4, wherein the housing encases a low friction rotatable toothed member whose teeth mesh with the teeth of the rack.
6. A bicycle as claimed in Claim 5, wherein the toothed member is a pinion wheel.
7. A bicycle as claimed in Claim 6, wherein the pinion wheel has a coaxial extension around which a helical groove is provided.
8. A bicycle as claimed in Claim 5, wherein the toothed member is a segment of a pinion wheel.
9. A bicycle as claimed in Claim 8, wherein a circumferential groove is provided mid-way through the teeth of the segmental pinion wheel.
10. A bicycle as claimed in Claim 7 or 9, wherein a cable is provided around the groove and anchored thereto, the ends of the cable passing out through a respective upright passage to be anchored to a lever, selected arcuate movement of which controlling rotational movement of the pinion wheel and therefore of longitudinal movement of shaft.
11. A bicycle as claimed in Claim 10, wherein the ends of the cable are anchored to a lever of the gear change mechanism whereby alteration of the gear synchronously alters the position of the chainring on the axle.
12. A bicycle as claimed in any one of Claims 3 to 11 , wherein the or each end of the shaft is tied to the axle by a link, the or each link having a bearing which permits only rotational movement of the axle.
13. A bicycle as claimed in any one of the preceding Claims, wherein the limb of the fork on the side on which the chain is positioned is shaped to avoid interference with movement of the chain with sliding adjustment of the axle and chainring.
14. A bicycle substantially as hereinbefore described with reference to the accompanying drawings.
PCT/GB1992/000250 1991-02-12 1992-02-12 Improvement relating to bicycles WO1992013752A1 (en)

Applications Claiming Priority (4)

Application Number Priority Date Filing Date Title
GB919102942A GB9102942D0 (en) 1991-02-12 1991-02-12 Bicycle bottom bracket with side-to-side linear movement
GB9102942.1 1991-02-12
GB919112976A GB9112976D0 (en) 1991-06-15 1991-06-15 Improvements relating to bicycles
GB9112976.7 1991-06-15

Publications (1)

Publication Number Publication Date
WO1992013752A1 true WO1992013752A1 (en) 1992-08-20

Family

ID=26298429

Family Applications (1)

Application Number Title Priority Date Filing Date
PCT/GB1992/000250 WO1992013752A1 (en) 1991-02-12 1992-02-12 Improvement relating to bicycles

Country Status (1)

Country Link
WO (1) WO1992013752A1 (en)

Cited By (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
GB2297528A (en) * 1995-01-31 1996-08-07 John James Lindsay Slidably adjustable front chainring axle of a bicycle
WO1997027099A1 (en) * 1996-01-25 1997-07-31 Robert Schmitt Bicycle chain drive with a derailleur
WO1998036960A1 (en) * 1997-02-21 1998-08-27 Josef Prajczer Bicycle gear system
DE102016014681B4 (en) 2015-12-14 2023-06-07 Shimano Inc. bicycle crank assembly

Citations (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3769848A (en) * 1972-06-26 1973-11-06 Guire W Mc Automatic shifting means for multispeed bicycles
FR2444609A1 (en) * 1978-12-21 1980-07-18 Bottin Georgette Derailleur reduction gear for bicycle - in which laterally sliding hub effects chain movement using two controls to give all functions
FR2553055A2 (en) * 1978-12-21 1985-04-12 Bottin Germaine Improved transmission reduction gear associated with a chain derailleur
DE3941119A1 (en) * 1989-12-13 1991-06-20 Egbert Greiss Sprocket assembly for derailleur change speed gear - incorporates hub which can slide axially on wheel hub

Patent Citations (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3769848A (en) * 1972-06-26 1973-11-06 Guire W Mc Automatic shifting means for multispeed bicycles
FR2444609A1 (en) * 1978-12-21 1980-07-18 Bottin Georgette Derailleur reduction gear for bicycle - in which laterally sliding hub effects chain movement using two controls to give all functions
FR2553055A2 (en) * 1978-12-21 1985-04-12 Bottin Germaine Improved transmission reduction gear associated with a chain derailleur
DE3941119A1 (en) * 1989-12-13 1991-06-20 Egbert Greiss Sprocket assembly for derailleur change speed gear - incorporates hub which can slide axially on wheel hub

Cited By (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
GB2297528A (en) * 1995-01-31 1996-08-07 John James Lindsay Slidably adjustable front chainring axle of a bicycle
GB2297528B (en) * 1995-01-31 1998-05-13 John James Lindsay Improvements relating to bicycles
WO1997027099A1 (en) * 1996-01-25 1997-07-31 Robert Schmitt Bicycle chain drive with a derailleur
WO1998036960A1 (en) * 1997-02-21 1998-08-27 Josef Prajczer Bicycle gear system
DE102016014681B4 (en) 2015-12-14 2023-06-07 Shimano Inc. bicycle crank assembly

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