Patent ID: 7210268

Claim:
A manually operated unlock mechanism for use with a rotary door operator for opening and closing a door of a transit vehicle door system, said rotary door operator having a mounting bracket, a drive cylinder enabled by a source of fluid pressure, an output shaft connected to a piston of said drive cylinder, said unlock mechanism comprising: (a) a first abutment adapted to be secured to said output shaft for axial movement therewith; (b) a first blocking means for blocking an axial linear movement of said first abutment during an unintended loss of said fluid pressure to said drive cylinder, said first blocking means being one of a cylinder and a solenoid; (c) a blocking member attached to said first blocking means, (d) at least one mounting tab asapted to be fixed relative to said mounting bracket; (e) a second blocking means pivotally attached to said mounting tab for rotating toward and away from said first abutment, said second blocking means pivotally attached to said blocking member to be driven thereby, a portion of said second blocking means in a locked position disposed underneath said first abutment for preventing a predetermined axial linear movement of said output shaft sufficient to open said door, said second blocking means being rotatable to an unlocked position for allowing said predetermined axial linear movement of said output shaft to open said door; (f) said first blocking means comprising a first biasing means for urging said second blocking means toward said locked position; (g) an unlock crank pivotally disposed relative to said mounting tab, said unlock crank having a portion engageable with said second blocking means to rotate said second blocking means from said locked position into said unlocked position; and (h) a pressure interruption means for discharging said fluid pressure from said drive cylinder during manual opening of said door, said pressure interruption means having an actuating portion engageable with said unlock crank.