초록 ▼

A hydraulic gear shift mechanism for a bicycle having a positioning mechanism for controlling the motion of the piston of a master cylinder assembly is disclosed, wherein the master cylinder assembly is in communication with a slave cylinder for operation of a derailleur. The positioning mechanism p

A hydraulic gear shift mechanism for a bicycle having a positioning mechanism for controlling the motion of the piston of a master cylinder assembly is disclosed, wherein the master cylinder assembly is in communication with a slave cylinder for operation of a derailleur. The positioning mechanism preferably includes a pivot shaft spaced apart from the handlebar, a rotating member rotatable about the pivot shaft, a push mechanism for rotating the rotating member in a first direction and a return mechanism for rotating the rotating member in a second direction. In a more preferred embodiment of the invention, an adjuster piston is threadingly engaged with the master cylinder assembly for adjusting the initial position of the slave cylinder.

대표청구항 ▼

What is claimed is: 1. A shift control device attachable to a handlebar of a bicycle for adjusting a slave piston of a slave cylinder assembly of a hydraulic gear shift mechanism, the shift control device comprising: a bracket attachable to the handlebar; a pivot shaft spaced apart from the handleb

What is claimed is: 1. A shift control device attachable to a handlebar of a bicycle for adjusting a slave piston of a slave cylinder assembly of a hydraulic gear shift mechanism, the shift control device comprising: a bracket attachable to the handlebar; a pivot shaft spaced apart from the handlebar and fixedly secured to the bracket; a member rotatable in a first direction and a second direction about the pivot shaft; a lever operatively connected with the member, wherein the lever is biased in a neutral position and movable in a first and second direction, wherein the neutral position is between the first and second directions, and wherein rotation of the member in the first direction moves the slave piston in a push direction and the rotation of the member in the second direction moves the slave piston in a return direction. 2. The shift control device of claim 1 further comprising a push mechanism configured to cooperate with and rotate the member in the first direction; a cooperate with and rotate the member in the first direction; a return mechanism configured to cooperate with and rotate the member in the second direction; a master cylinder assembly having a master piston operatively connected to the member; and an adjusting piston adjustably extending into the master cylinder assembly. 3. The shift control device of claim 2, wherein the master cylinder assembly comprises a master chamber and an adjuster chamber, the primary piston is disposed in the master chamber, and the adjuster piston is disposed in the adjuster chamber. 4. The shift control device of claim 2, wherein the push mechanism comprises a first latch segment and a push pawl biased toward the first latch segment and configured to cooperate with the first latch segment to rotate the member in a first direction, and wherein the return mechanism comprises a second latch segment and a return pawl, the return pawl having a first claw and a second claw which alternately engage the second latch segment when the member is rotating in the second direction. 5. The shift control device of claim 4 further comprising a pinion gear rotatable about the pivot shaft and operatively connected to the member wherein the pinion gear rotates with the member; and a rack gear engaged with the pinion gear and operatively connected to the master piston of the master cylinder assembly, wherein the rotation of the member in the first direction corresponds to a movement of the piston in a push direction and the rotation in the second direction corresponds to a movement of the piston in a return direction. 6. The shift control device of claim 2 wherein the master cylinder assembly comprises a main chamber for the master piston and an adjuster chamber for the adjusting piston, the master piston is adjustable to vary the depth of the master cylinder in the master chamber, the adjusting piston is adjustable to vary the depth of the adjusting piston in the adjuster chamber, and both the depth of the master piston in the master chamber and the depth of the adjusting piston in the adjuster chamber define a volume of hydraulic fluid in the master cylinder assembly. 7. The shift control device of claim 1 wherein the pivot shaft is substantially vertically oriented. 8. A shift control device attachable to a handlebar of a bicycle for adjusting a slave piston of a slave cylinder assembly of a hydraulic shift gear mechanism, the shift control device comprising: a bracket attachable to the handlebar; a pivot shaft spaced apart from the handlebar and fixedly secured to the bracket; a member rotatable in a first direction and a second direction about the pivot shaft; a lever operatively connected with the member, wherein the lever is biased in a neutral position and movable in a first and second direction, wherein the neutral position is between the first and second directions, and wherein when the lever is moved away from the neutral position in one selected from the first direction and the second direction and then subsequently released, the lever returns to the neutral position. 9. The shift control device of claim 8 further comprising a push mechanism configured to cooperate with and rotate the member in the first direction; a return mechanism configured to cooperate with and rotate the member in the second direction; a master cylinder assembly having a master piston operatively connected to the member; and an adjusting piston adjustably extending into the master cylinder assembly. 10. The shift control device of claim 9, wherein the master cylinder assembly comprises a master chamber and an adjuster chamber, the primary piston is disposed in the master chamber, and the adjuster piston is disposed in the adjuster chamber. 11. The shift control device of claim 9, wherein the push mechanism comprises a first latch segment and a push pawl biased toward the first latch segment and configured to cooperate with the first latch segment to rotate the member in a first direction, and wherein the return mechanism comprises a second latch segment and a return pawl, the return pawl having a first claw and a second claw which alternately engage the second latch segment when the member is rotating in the second direction. 12. The shift control device of claim 11 further comprising a pinion gear rotatable about the pivot shaft and operatively connected to the member wherein the pinion gear rotates with the member; and a rack gear engaged with the pinion gear and operatively connected to the master piston of the master cylinder assembly, wherein the rotation of the member in the first direction corresponds to a movement of the piston in a push direction and the rotation in the second direction corresponds to a movement of the piston in a return direction. 13. The shift control device of claim 9 wherein the master cylinder assembly comprises a main chamber for the master piston and an adjuster chamber for the adjusting piston, the master piston is adjustable to vary the depth of the master cylinder in the master chamber, the adjusting piston is adjustable to vary the depth of the adjusting piston in the adjuster chamber, and both the depth of the master piston in the master chamber and the depth of the adjusting piston in the adjuster chamber define a volume of hydraulic fluid in the master cylinder assembly.