WO1982000274A1 - Extension bracket for bicycle rear derailleur - Google Patents
Extension bracket for bicycle rear derailleur Download PDFInfo
- Publication number
- WO1982000274A1 WO1982000274A1 PCT/US1981/000960 US8100960W WO8200274A1 WO 1982000274 A1 WO1982000274 A1 WO 1982000274A1 US 8100960 W US8100960 W US 8100960W WO 8200274 A1 WO8200274 A1 WO 8200274A1
- Authority
- WO
- WIPO (PCT)
- Prior art keywords
- bicycle
- slot
- extension bracket
- bracket
- rear derailleur
- Prior art date
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
- B62M9/12—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 chain, belt, or the like being laterally shiftable, e.g. using a rear derailleur
- B62M9/121—Rear derailleurs
- B62M9/125—Mounting the derailleur on the frame
Definitions
- My invention relates to bicycle accessories and more particularly to accessories which improve the performance of a bicycle's powering mechanism.
- a bicyclist With the type of bicycle having at least one crank gear, a cluster of gears coupled to the rear wheel axle, a drive chain engaged with the crank gear, and a rear derailleur mechanism for selectively engaging the drive chain with one of the rear cluster of gears, a bicyclist can produce the greatest amount of rear wheel torque when the largest gear of the rear cluster is engaged.
- the maximum torque developed at the rear wheel has heretofore been limited by the largest gear a standard rear derailleur can accomodate, which is a 38 tooth alpine gear.
- a 38 tooth gear insufficient torque is produced to climb some very steep grades.
- a bicycle's rear cluster of gears could not include a gear with more than 38 teeth unless a standard rear derailleur mechanism were modified to accomodate it. Modifying a derailleur mechanism has many disadvantages including decreased reliability of the mechanism, and the non-reversibility of such modifications.
- a rear derailleur 'extension bracket comprising an elongated plate provided with a pair of spaced, parallel slots, the bracket being associated with fasteners which attach the bracket between the rear axle assembly and the rear derailleur mechanism.
- the extension bracket lowers the derailleur so that it can accomodate an oversized gear added to the rear cluster of gears.
- My extension bracket is advantageous in that it is simple in structure, and does not impair the performance nor does it modify the construction of the bicycle's original rear derailleur. Since the rear derailleur is radially extended from its normal position, much larger rear gears can be used with a resultant enhancement of the bicycle's hill climbing capabilities.
- the slotted structure of the bracket allows it to be used with virtually any make of bicycle, and to be adjusted as perfectly as possible to a particular bicycle.
- Fig. 1 is an elevational view
- Fig. 2 is a cross-sectional view along line 2-2 of Fig. 1
- Fig. 3 is an elevational view of the bracket operationally attached to a bicycle.
- a rear derailleur extension bracket 10 includes a plate 12 provided with a pair of elongated, linear, parallel slots 14 and 16.
- the bracket is associated with a number of fasteners including a nut and bolt 18 and screws 20 and 22.
- Plate 10 is quadrilateral with two parallel sides 24 and 26, and a side 28 substantially perpendicular the parallel sides. The remaining side 30 meets side 24 at an acute angle and side 26 at an obtuse angle. The corners of the bracket are rounded for safety.
- Slots 14 and 16 are preferably formed parallel to sides 24 and 26. Slot 14 is wider than slot 16 so that it can accomodate the shafts of larger bolts and studs.
- the bracket is preferably constructed from a strong, lightweight material such as aluminum, stainless steel, platic, or any of the numerous alloys known to the bicycle trade. It may be formed by stamping, casting, molding, machining, or any other suitable process.
- bracket 10 is attached to a bicycle including: a frame 32; a rear axle assembly having a rear cluster 34, an axle stud 36, and an axle nut 38; a rear derailleur 40; and a chain 42.
- the axle stud is positioned within slot 14 and is affixed to the bracket by axle nut 38.
- the rear derailleur assembly is attached to slot 14 of the bracket by nut and bolt 18.
- Screw 20 is disposed through slot 16 and engages the bicycle's frame, and screw 22 is likewise disposed through slot 16 and engages the rear derailleur assembly.
- the bracket can be easily removed to return the bicycle to its original condition.
- side 30 is designed to match the contours of that portion of the bicycle's frame to which it attaches. While this is an aesthetically pleasing feature, it is not a necessity because it has been found that the extension bracket works equally well when inverted on some makes of bicycles.
- bracket 12 While the derailleur is shown to be attached to the rear of bracket 12, it could equally well be attached to the front of the bracket in many cases. Should axial positioning of the derailleur become necessary, spacers such as washers 44 can be disposed around the shafts of the nuts and bolts.
- An oversized gear 46 has been added to the rear cluster to illustrate the use of the present device.
- the bracket assembly allows the derailleur to be displaced downwardly from the rear axle of the bicycle so that chain 42 can be dropped around the oversized gear. Without the extension provided by the present bracket this would not be possible.
- the bracket is slotted so that it might be fitted to a wide variety of bicycles and so that it can be adjusted to fit any particular bicycle as perfectly as possible. However, the bracket might be provided with only one slot, or even just some bore holes, should that be all that was necessary to fit the bracket to a particular bicycle.
Landscapes
- Engineering & Computer Science (AREA)
- Chemical & Material Sciences (AREA)
- Combustion & Propulsion (AREA)
- Transportation (AREA)
- Mechanical Engineering (AREA)
- Axle Suspensions And Sidecars For Cycles (AREA)
Abstract
Extension bracket for lowering the rear derailleur assembly of a bicycle so that an oversized, high torque gear can be added to the rear gear cluster of the bicycle. With reference to Fig. 3 of the drawing, said bracket includes a plate (10) provided with a pair of elongated, parallel slots (14 and 16). The bicycle's rear axle stud (36) and nut (38) adjustably engage an upper portion of the wider slot (14), and a nut and bolt (18) adjustably attach the bicycle's rear derailleur assembly (40) to a lower portion of the wider slot (14). Narrow slot (16) provides supplemental adjustable attachment of the plate (10) to the bicycle's frame (32) and rear derailleur assembly (40) by means of a pair of fasteners (20 and 22). When the extension bracket is in place an oversized gear (46) can be accommodated by the extended derailleur assembly. The gear (46) greatly increases the torque that can be developed at the rear wheel and thus enhances the hill climbing capabilities of the bicycle.
Description
Description
Extension Bracket for Bicvcle Rear Derailleur
Technical. Field
My invention relates to bicycle accessories and more particularly to accessories which improve the performance of a bicycle's powering mechanism.
With the type of bicycle having at least one crank gear, a cluster of gears coupled to the rear wheel axle, a drive chain engaged with the crank gear, and a rear derailleur mechanism for selectively engaging the drive chain with one of the rear cluster of gears, a bicyclist can produce the greatest amount of rear wheel torque when the largest gear of the rear cluster is engaged. Thus the maximum torque developed at the rear wheel has heretofore been limited by the largest gear a standard rear derailleur can accomodate, which is a 38 tooth alpine gear. Unfortunately, even with a 38 tooth gear insufficient torque is produced to climb some very steep grades.
Background Art
Prior to this invention a bicycle's rear cluster of gears could not include a gear with more than 38 teeth unless a standard rear derailleur mechanism were modified to accomodate it. Modifying a derailleur mechanism has many disadvantages including decreased reliability of the mechanism, and the non-reversibility of such modifications.
Disclosure of the Invention
In accordance with the present invention, I provide a rear derailleur 'extension bracket comprising an elongated plate provided with a pair of spaced, parallel slots, the bracket being associated with fasteners which
attach the bracket between the rear axle assembly and the rear derailleur mechanism. The extension bracket lowers the derailleur so that it can accomodate an oversized gear added to the rear cluster of gears. My extension bracket is advantageous in that it is simple in structure, and does not impair the performance nor does it modify the construction of the bicycle's original rear derailleur. Since the rear derailleur is radially extended from its normal position, much larger rear gears can be used with a resultant enhancement of the bicycle's hill climbing capabilities. Furthermore, the slotted structure of the bracket allows it to be used with virtually any make of bicycle, and to be adusted as perfectly as possible to a particular bicycle.
Brief Description of the Drawings
The details of my invention will be described in connection with the accompanying drawing, in which Fig. 1 is an elevational view; Fig. 2 is a cross-sectional view along line 2-2 of Fig. 1; and Fig. 3 is an elevational view of the bracket operationally attached to a bicycle.
Best Mode for Carrying Out the Invention
Referring to the drawing, a rear derailleur extension bracket 10 includes a plate 12 provided with a pair of elongated, linear, parallel slots 14 and 16. The bracket is associated with a number of fasteners including a nut and bolt 18 and screws 20 and 22.
Plate 10 is quadrilateral with two parallel sides 24 and 26, and a side 28 substantially perpendicular the parallel sides. The remaining side 30 meets side 24 at an acute angle and side 26 at an obtuse angle. The corners of the bracket are rounded for safety.
Slots 14 and 16 are preferably formed parallel to sides 24 and 26. Slot 14 is wider than slot 16 so that it can accomodate the shafts of larger bolts and studs.
The bracket is preferably constructed from a strong, lightweight material such as aluminum, stainless steel, platic, or any of the numerous alloys known to the bicycle trade. It may be formed by stamping, casting, molding, machining, or any other suitable process.
Referring more particularly to Fig. 3, bracket 10 is attached to a bicycle including: a frame 32; a rear axle assembly having a rear cluster 34, an axle stud 36, and an axle nut 38; a rear derailleur 40; and a chain 42. The axle stud is positioned within slot 14 and is affixed to the bracket by axle nut 38. The rear derailleur assembly is attached to slot 14 of the bracket by nut and bolt 18. Screw 20 is disposed through slot 16 and engages the bicycle's frame, and screw 22 is likewise disposed through slot 16 and engages the rear derailleur assembly. The bracket can be easily removed to return the bicycle to its original condition.
It will be noted that side 30 is designed to match the contours of that portion of the bicycle's frame to which it attaches. While this is an aesthetically pleasing feature, it is not a necessity because it has been found that the extension bracket works equally well when inverted on some makes of bicycles.
It will also be noted that while the derailleur is shown to be attached to the rear of bracket 12, it could equally well be attached to the front of the bracket in many cases. Should axial positioning of the derailleur become necessary, spacers such as washers 44 can be disposed around the shafts of the nuts and bolts. An oversized gear 46 has been added to the rear cluster to illustrate the use of the present device. The bracket assembly allows the derailleur to be displaced downwardly from the rear axle of the bicycle so that chain 42 can be dropped around the oversized gear. Without the extension provided by the present bracket this would not be possible.
The bracket is slotted so that it might be fitted to a wide variety of bicycles and so that it can be adjusted to fit any particular bicycle as perfectly as possible. However, the bracket might be provided with only one slot, or even just some bore holes, should that be all that was necessary to fit the bracket to a particular bicycle.
The foregoing and other advantages are obvious to those skilled in the art of bicycle design.
Claims
1. In a bicycle including a frame, a rear derailleur assembly, and a rear axle assembly; a rear derailleur extension bracket characterized by: a plate provided with a first elongated, substantially vertically oriented slot having an upper portion adapted to adjustably engage said rear axle assembly; and first means for adjustably engaging said rear derailleur assembly with a lower portion of said first slot, whereby said derailleur assembly is radially displaced from said rear axle assembly.
2. The extension bracket of claim 1 further characterized by means for axially spacing said plate from said rear axle assembly.
3. The extension bracket of claim 1 further characterized by means for axially spacing said plate from said rear derailleur assembly.
4. The extension bracket of claim 1 wherein said plate is further provided with a second elongated slot spaced from and substantially parallel to said first slot.
5. The extension bracket of claim 4 further characterized by second means for adjustably engaging said frame with an upper portion of said second slot, and third means for adjustably engaging said said rear derailleur assembly with a lower portion of said second slot.
6. The extension bracket of claim 4 wherein the lateral dimension of said first slot is greater than the lateral dimension of said second slot.
7. The extension bracket of claim 4 wherein said plate is quadrilaterial with two of its sides parallel to said first slot and said second slot.
Priority Applications (1)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
AU74511/81A AU7451181A (en) | 1980-07-18 | 1981-07-17 | Extension bracket for a bicycle rear derailleur |
Applications Claiming Priority (2)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
US17013780A | 1980-07-18 | 1980-07-18 | |
US170137800718 | 1980-07-18 |
Publications (1)
Publication Number | Publication Date |
---|---|
WO1982000274A1 true WO1982000274A1 (en) | 1982-02-04 |
Family
ID=22618688
Family Applications (1)
Application Number | Title | Priority Date | Filing Date |
---|---|---|---|
PCT/US1981/000960 WO1982000274A1 (en) | 1980-07-18 | 1981-07-17 | Extension bracket for bicycle rear derailleur |
Country Status (2)
Country | Link |
---|---|
EP (1) | EP0056053A1 (en) |
WO (1) | WO1982000274A1 (en) |
Citations (7)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US852872A (en) * | 1906-04-18 | 1907-05-07 | John S Collins | Adjustable umbrella-support. |
US1397456A (en) * | 1917-02-24 | 1921-11-15 | Charles H Robinson | Window-shade bracket |
FR597838A (en) * | 1925-03-25 | 1925-11-30 | Freewheel sprocket with two direct speeds for bicycles | |
GB382104A (en) * | 1931-11-25 | 1932-10-20 | Alec Shuttleworth | Improvements in change speed gearing for bicycles and similarly propelled vehicles |
GB407505A (en) * | 1933-01-21 | 1934-03-22 | Louis Camillis | Improvements in chain shifting devices for cycles |
FR45176E (en) * | 1934-07-16 | 1935-07-06 | Gear shifting for chain derailment cycles | |
DE876223C (en) * | 1949-10-28 | 1953-05-11 | Hermann Buechner | Locking device for the spring-loaded tensioning arm of a chain switching device of a bicycle or similar vehicle |
-
1981
- 1981-07-17 EP EP19810902144 patent/EP0056053A1/en not_active Withdrawn
- 1981-07-17 WO PCT/US1981/000960 patent/WO1982000274A1/en unknown
Patent Citations (7)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US852872A (en) * | 1906-04-18 | 1907-05-07 | John S Collins | Adjustable umbrella-support. |
US1397456A (en) * | 1917-02-24 | 1921-11-15 | Charles H Robinson | Window-shade bracket |
FR597838A (en) * | 1925-03-25 | 1925-11-30 | Freewheel sprocket with two direct speeds for bicycles | |
GB382104A (en) * | 1931-11-25 | 1932-10-20 | Alec Shuttleworth | Improvements in change speed gearing for bicycles and similarly propelled vehicles |
GB407505A (en) * | 1933-01-21 | 1934-03-22 | Louis Camillis | Improvements in chain shifting devices for cycles |
FR45176E (en) * | 1934-07-16 | 1935-07-06 | Gear shifting for chain derailment cycles | |
DE876223C (en) * | 1949-10-28 | 1953-05-11 | Hermann Buechner | Locking device for the spring-loaded tensioning arm of a chain switching device of a bicycle or similar vehicle |
Also Published As
Publication number | Publication date |
---|---|
EP0056053A1 (en) | 1982-07-21 |
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AK | Designated states |
Designated state(s): AU DE GB JP |
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AL | Designated countries for regional patents |
Designated state(s): FR |