Bicycle gear shifting system

Patent metadata

Field	Value
Publication number	US-11912374-B2
Application number	US-202218071352-A
Country	US
Kind code	B2
Filing date	Nov 29, 2022
Priority date	Nov 1, 2018
Publication date	Feb 27, 2024
Grant date	Feb 27, 2024

Abstract

A bicycle front shifting system includes operable to transmit a wireless signal, a crank assembly with two crank arms and a pedal on each of the two crank arms. The crank assembly is rotatable about a rotation axis. A front shift unit is coupled to the crank assembly and is rotatable about the rotation axis. The front shift unit includes a chain ring component with a big chain ring and a small chain ring. The small chain ring has a small diameter and the big chain ring has a big diameter that is larger than the small diameter. A shift mechanism is coupled to and rotatable with the chain ring component about the rotation axis. The shift mechanism is configured to receive the wireless signal from the shifter and to shift a chain between the big chain ring and the small chain ring according to the wireless signal.

First claim

What is claimed is:

1. A front shifting system for a bicycle, the front shifting system comprising:
a shifter mountable on a bicycle, the shifter operable to transmit a wireless signal;
a crank assembly configured to include two crank arms and a pedal associated with each of the two crank arms, the crank assembly rotatable about a rotation axis;
a chain; and
a front shift unit coupled to the crank assembly and rotatable about the rotation axis, the front shift unit including
a chain ring component with a big chain ring and a small chain ring, the small chain ring having a small diameter and the big chain ring having a big diameter that is larger than the small diameter, and
a shift mechanism coupled to and rotatable with the chain ring component about the rotation axis, the shift mechanism configured to receive the wireless signal from the shifter and to shift the chain between the big chain ring and the small chain ring according to the wireless signal,
wherein the shift mechanism includes an electronic control unit, a gearmotor unit in communication with the electronic control unit, at least one upshift element coupled to the gearmotor unit, at least one downshift element coupled to the gearmotor unit, and a battery arranged to provide power for the electronic control unit and the gearmotor unit to operate the at least one upshift element and the at least one downshift element, and
wherein the at least one downshift element includes a first downshift element and a second downshift element positioned opposite the first downshift element around a circumference of the chain ring component.

2. The front shifting system of claim 1 , the shifter being mountable on the bicycle remote from the front shift unit.

3. The front shifting system of claim 1 , wherein, according to a wireless upshift signal received by the electronic control unit, the at least one upshift element is operable by the gearmotor unit to shift the chain from the small chain ring to the big chain ring, and
wherein, according to a wireless downshift signal received by the electronic control unit, the at least one downshift element is operable by the gearmotor unit to shift the chain from the big chain ring to the small chain ring.

4. The front shifting system of claim 1 , wherein the first downshift element and the at least one upshift element are operable by a first link coupled to the gearmotor unit.

5. The front shift unit of claim 4 , wherein the second downshift element is operable by a second link coupled to the gearmotor unit.

6. The front shifting system of claim 4 , wherein the shift mechanism further comprises:
a first cam shaft coupled to the gearmotor unit and rotatable about a first cam axis;
an upshift driver rotatable about the first cam axis and configured to move the at least one upshift element between an upshift state engaging the chain on the small chain ring and a neutral state not engaging the chain on the chain ring component; and
a first downshift driver rotatable about the first cam axis and configured to move the first downshift element between a downshift state engaging the chain on the big chain ring and a neutral state not engaging the chain on the chain ring component.

7. The front shifting system of claim 6 , wherein, when the at least one upshift element moves to the upshift state, the first downshift element is in the neutral state, and wherein, when the first downshift element moves to the downshift state, the upshift element is in the neutral state.

8. The front shifting system of claim 6 , wherein the shift mechanism further comprises:
a second cam shaft coupled to the gearmotor unit and rotatable about a second cam axis; and
a second downshift driver rotatable about the second cam axis and configured to move the second downshift element between the downshift state engaging the chain on the big chain ring and the neutral state not engaging the chain on the chain ring component.

9. The front shifting system of claim 8 , wherein, when the at least one upshift element moves to the upshift state, the first and second downshift elements are in the neutral state, and wherein, when the first and second downshift elements move to the downshift state, the upshift element is in the neutral state.

10. The front shifting system of claim 8 , wherein the first and second downshift elements move in concert with one another between the downshift state and the neutral state.

11. The front shifting system of claim 1 , wherein the chain ring component is formed as one integral structure including the big chain ring and the small chain ring.

12. A front shifting system for a bicycle, the front shifting system comprising:
a shifter mountable on a bicycle, the shifter operable to transmit a wireless signal;
a crank assembly configured to include two crank arms and a pedal associated with each of the two crank arms, the crank assembly rotatable about a rotation axis;
a chain; and
a front shift unit coupled to the crank assembly and rotatable about the rotation axis, the front shift unit including
a chain ring component with a big chain ring and a small chain ring, the small chain ring having a small diameter and the big chain ring having a big diameter that is larger than the small diameter, and
a shift mechanism coupled to and rotatable with the chain ring component about the rotation axis, the shift mechanism configured to receive the wireless signal from the shifter and to shift the chain between the big chain ring and the small chain ring according to the wireless signal,
wherein the shift mechanism includes an electronic control unit, a gearmotor unit in communication with the electronic control unit, at least one upshift element coupled to the gearmotor unit, at least one downshift element coupled to the gearmotor unit, and a battery arranged to provide power for the electronic control unit and the gearmotor unit to operate the at least one upshift element and the at least one downshift element, and wherein each of the electronic control unit, the gearmotor unit, the at least one upshift element, the at least one downshift element, and the battery are carried on the big chain ring of the chain ring component.

Assignees

• Sram Llc

Inventors

• Shipman Christopher
• Jordan Brian
• Hahn Sage

Classifications

• B62M9/04

  of changeable ratio · CPC title

• B62M9/1346 Primary

  using cams or plates · CPC title

• B62M9/105

  involving front sprocket chain-wheels engaged by the chain, belt or the like · CPC title

• B62M9/132 Primary

  electrically or fluid actuated; Controls thereof · CPC title

• B62M9/134

  Mechanisms for shifting laterally · CPC title