# US 5,706,918 A · Brake apply mechanism > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 5,706,918 A - Document ID: US5706918A - Status: Granted - Kind: A - Application number: 08/578,417 - Filed: 1995-12-26 - Granted: 1998-01-13 - Earliest claimed: 1995-12-26 - Assignees: General Motors Corporation - Inventors: James Allan Redelman - Web page: https://patentgrep.com/patent/US5706918A ## CPC - B60T 13/22: Brakes applied by springs or weights and released hydraulically - B60T: VEHICLE BRAKE CONTROL SYSTEMS OR PARTS THEREOF; BRAKE CONTROL SYSTEMS OR PARTS THEREOF, IN GENERAL (electrodynamic brake systems for vehicle, in general B60L; brakes per se, i.e. devices where braking effect occurs, including ultimate brake actuators, F16D); ARRANGEMENT OF BRAKING ELEMENTS ON VEHICLES IN GENERAL; PORTABLE DEVICES FOR PREVENTING UNWANTED MOVEMENT OF VEHICLES; VEHICLE MODIFICATIONS TO FACILITATE COOLING OF BRAKES ## Abstract A brake apply mechanism for a power transmission is provided which includes a planetary gear set having a ring gear member, a carrier assembly member and a sun gear member; an operator-controlled brake apply mechanism operatively connected to the sun gear member to selectively enforce rotation thereof; an auxiliary spring applied hydraulically released brake apply mechanism selectively operable to enforce rotation of the ring gear member to initiate brake engagement; and a brake apply mechanism operatively connected to the carrier assembly member to enforce brake engagement when either the operator control brake apply mechanism or the auxiliary brake apply mechanism is operated. ## Claims ### Claim 1 A brake apply mechanism comprising: a brake pedal; a vehicle transmission including a planetary gear set with a ring gear and a carrier assembly operatively connecting a plurality of planet gears within the ring gear wherein the planet gears rotate around a sun gear and mesh with a first set of gear teeth of the sun gear with a substantially straight rack gear engaging the sun gear at a second set of gear teeth; a linkage connecting the brake pedal to the rack gear wherein operation of the brake pedal transmits movement through the linkage to the rack gear causing the rack gear to move rotating the sun gear and causing the carrier to move to apply the brake apply mechanism within the vehicle transmission; an auxiliary brake apply mechanism including an auxiliary linkage connected with the ring gear and a piston rod wherein the piston rod is connected to a piston that is carried with a spring on a first side of the piston and a hydraulic pressure chamber on a second side of the piston wherein when a hydraulic pressure release is enabled from the hydraulic pressure chamber, the spring moves the piston into the hydraulic pressure chamber, moving the auxiliary linkage through the piston rod with the auxiliary linkage causing the ring gear to rotate the carrier in a brake apply direction; and, a line connecting the hydraulic pressure chamber to a cylinder wherein the cylinder carries a spool piston alternately registering with a hydraulic pressure line and an exhaust line so that when the spool piston registers with the hydraulic pressure line, hydraulic pressure is conveyed through the line to the hydraulic pressure chamber causing the piston to compress the spring releasing the auxiliary brake apply mechanism and when the spool piston registers with the exhaust line, hydraulic pressure is released from the hydraulic pressure chamber allowing the spring to move the piston to apply the auxiliary brake apply mechanism; wherein the planetary gear set provides a mechanical advantage to the brake pedal in applying the brake apply mechanism of approximately 3:1 to 6:1 so that the brake apply mechanism is applied without hydraulic brake apply assist. ### Claim 2 A brake apply mechanism for a power transmission comprising: a planetary gear set having a ring gear member, a carrier assembly member and a sun gear member; an operator-controlled brake apply mechanism operatively connected to one of the members of the planetary gear set to selectively enforce rotation there of through a rack gear that engages the sun gear wherein the rack gear is manipulated by a linkage that engages the rack gear wherein the linkage is manipulated by an operator-controlled brake pedal that engages the linkage; an auxiliary brake apply mechanism selectively operable to enforce rotation of another of the members of the planetary gear set to initiate brake engagement; and a brake apply mechanism operatively connected to yet another of the members of the planetary gear set to enforce brake engagement when either the operator control brake apply mechanism or the auxiliary brake apply mechanism is operated. ### Claim 3 (depends on 2) A brake apply mechanism as described in claim 2 wherein the brake apply mechanism is operatively connected to the carrier assembly. ### Claim 4 (depends on 2) A brake apply mechanism as described in claim 2 wherein the auxiliary brake apply mechanism is selectively operable to enforce rotation of the ring gear. ### Claim 5 (depends on 2) A brake apply mechanism as described in claim 2 wherein the auxiliary brake apply mechanism is spring actuated with a hydraulic release. ### Claim 6 A brake apply mechanism for a power transmission comprising: a planetary gear set having a ring gear member, a carrier assembly member and a sun gear member; an operator-controlled brake apply mechanism operatively connected to the sun gear member to selectively enforce rotation thereof; an auxiliary spring applied hydraulically released brake apply mechanism selectively operable to enforce rotation of the ring gear member to initiate brake engagement; and a brake apply mechanism operatively connected to the carrier assembly member to enforce brake engagement when either the operator control brake apply mechanism or the auxiliary brake apply mechanism is operated. ### Claim 7 (depends on 6) A brake apply mechanism as described in claim 6 wherein the auxiliary spring applied hydraulically released brake apply mechanism includes a linkage that is connected with the ring gear member, and a piston connected to the linkage through a piston rod. ### Claim 8 (depends on 7) A brake apply mechanism as described in claim 7 further comprising a valve, wherein the valve is normally open to supply a fluid pressure to the auxiliary spring applied hydraulically released brake apply mechanism to prevent actuation of the brake apply mechanism and wherein, when the valve is supplied with a hydraulic signal through a line connected to the valve, a valve piston in the valve is shifted cutting off the fluid pressure to the auxiliary spring applied hydraulically released brake apply mechanism wherein the ring gear is rotated by action of a spring in the auxiliary spring applied hydraulically released brake apply mechanism. ### Claim 9 A brake apply mechanism comprising: a brake pedal; a vehicle transmission including a planetary gear set with a ring gear and a carrier assembly operatively connecting a plurality of planet gears within the ring gear wherein the planet gears rotate around a sun gear and mesh with a first set of gear teeth of the sun gear with a substantially straight rack gear engaging the sun gear at a second set of gear teeth; and, a linkage connecting the brake pedal to the rack gear wherein operation of the brake pedal transmits movement through the linkage to the rack gear causing the rack gear to move rotating the sun gear and causing the carrier to move to apply the brake apply mechanism within the vehicle transmission. ### Claim 10 (depends on 9) A brake apply mechanism according to claim 9 wherein the planetary gear set provides a mechanical advantage to the brake pedal in applying the brake apply mechanism of approximately 3:1 to 6:1 so that the brake apply mechanism is applied without hydraulic brake apply assist. ### Claim 11 (depends on 9) A brake apply mechanism according to claim 9 further comprising: an auxiliary brake apply mechanism including an auxiliary linkage connected with the ring gear and a piston rod wherein the piston rod is connected to a piston that is carried with a spring on a first side of the piston and a hydraulic pressure chamber on a second side of the piston wherein when a hydraulic pressure release is enabled from the hydraulic pressure chamber, the spring moves the piston into the hydraulic pressure chamber, moving the auxiliary linkage through the piston rod with the auxiliary linkage causing the ring gear to rotate the carrier in a brake apply direction. ### Claim 12 (depends on 11) A brake apply mechanism according to claim 11 further comprising: a line connecting the hydraulic pressure chamber to a cylinder wherein the cylinder carries a spool piston alternately registering with a hydraulic pressure line and an exhaust line so that when the spool piston registers with the hydraulic pressure line, hydraulic pressure is conveyed through the line to the hydraulic pressure chamber causing the piston to compress the spring releasing the auxiliary brake apply mechanism and when the spool piston registers with the exhaust line, hydraulic pressure is released from the hydraulic pressure chamber allowing the spring to move the piston to apply the auxiliary brake apply mechanism.