Lock and emergency release system for power operated doors

A lock and emergency release system for a sliding door normally power operated by a door operator, the system comprising a lock displaceable between an idle position to a functional position in which the door operator is prevented from opening the door, at least one emergency release means manually operable for displacing said lock to said idle position thereof and releasing the door from said door operator, thereby allowing the door to be manually opened, said system further includes a driven member for operatively connecting said emergency release means to the door operator, wherein said lock includes a key drum and a latch bolt displaceable by said key drum, said key drum being rotatable between unlocked and locked positions for respectively retracting and extending said latch bolt, said driven member being rotatably mounted about said key drum, and wherein a torque transferring member is provided between said driven member and said key drum for allowing said driven member to rotate said key drum from said locked position to said unlocked position, while allowing said driven member to rotate independently of said key drum between limit positions thereof when said key drum is in said unlocked position.