929,627. Door operating appliances and fastenings. C. B. BEDNAR. March 17, 1960 [March 18, 1959], No. 9476/60. Classes 44 and 65 (1). A power arrangement for operating a door and for locking it in any desired position comprises an electric motor, a gear train including at least a pair of gears of the self-locking type capable of transmitting force only from the motor to the door, and remotely actuated means for separating a pair of gears in the train to release the self-locking action. The invention is described with reference to jail doors provided with tamper-proof locks associated with the driving mechanism, the remotely actuated means also releasing the locks so that the doors may be opened manually by the prisoners in an emergency or leaving them locked for selective manual unlocking by a jailor. The door 20 is carried by an L-shaped member 27 (Figs. 1, 2) bolted to an inverted L-shaped carriage 23 mounted on rollers 24, 25 riding on a track 26. A toothed rack 28 fastened within a U-shaped channel member 36 is slidable on the top surface 23a of the carriage and carries on its right end a cam 29 which co-operates with a latch 30 pivoted on the carriage to lock the rack and carriage together during power operation of the door. A spring coupling is also provided between the rack and the carriage for biasing the rack to the right when the latch is released, and comprises a spring 161 compressed between one end wall 157 of a bracket 156 welded to the carriage and a washer 159 anchored on a rod 153 passing through the spring and secured by means of a bracket 152 and slide block 151 to the rack. The electric motor 50 is pivotally mounted at 52 and drives through an overload slip clutch 130 (not shown) a worm 55 meshed with a worm gear 56 fixed on the same shaft 60 as a larger spur gear 57 meshed with the rack. An arm 64 (Fig. 5) carrying a roller 63 for cooperation with the cam 29 is fixed on a shaft 66 pivoted in the fixed door frame and an arm 68 also fixed on the shaft operates two locks, a drop bolt 72 connected through a lost-motion coupling 72a, 74 with a vertically reciprocable latch member 75 (Fig. 1) which co-operates with a keeper 76 on the door, and a lock bar 80 carrying a projecting block 83 which engages a notch 84 in the top 23a of the carriage. By virtue of the lost-motion coupling the arm 68 and lock bar 80 are not prevented from dropping if a prisoner prevents the latch member 75 from dropping, e.g. by filling the notch 77 in keeper 76. During closing movement of the door the spring 161 is fully compressed and the latch 30 is in engagement with abutment surface 29b of cam 29. When the door is nearly closed cam surface 60 engages roller 63 and turns the arms 64, 68 anti-clockwise to raise drop bolt 72 and lock bar 80. As the roller 63 reaches the left end of the top surface 61 of the cam the inclined bottom face 30b of the latch 30 engages a fixed abutment 40 and the latch disengages from the surface 29b. Simultaneously a shoulder 91 on the carriage 23 engages a fixed stop 90 to prevent further movement of the carriage to the right, the door at this stage being fully closed. The rack continues to move to the right and roller 63 descends cam surface 62 to lower arm 68 and lock the door. During this final movement of the rack spring 161 expands and slide block 151 comes into contact with the right end of a slot 150 in the carriage 23, thus providing, by virtue of the worm 55, a third lock for the door. The unlocking and opening of the door is achieved simply by reversing the motor, limit switches being employed where necessary to regulate both the opening and closing movement. The sides of the channel member 36 extend above the level of the rack teeth and form a lubricant reservoir, lubricant being carried up by the gear 57 during operation to lubricate the gear 56 and worm 55. Manual operation.-The gear-motor housing 59 carries a horizontal rod 92a riding in a slot 92b in a plate 92 fixed to a horizontally reciprocable shaft 95. When the gear is meshed with the rack 28 the rod 92a rests in a seat 92c in the slot, and is prevented from rising by a member 140 floatingly mounted on shaft 95 and located over a projection 143 on the housing. Movement of the shaft to the right causes the rod 92a to rise into the part 92e of the slot and lifts gear 57 clear of the rack, while a plate 100 carried by the shaft is moved so that a keyhole 101 therein registers with a similar hole in a cover-plate 102 (not shown) to enable a jailor to insert a key to turn the shaft 66 and unlock the door. Further movement of the shaft 95 to the right, during which the rod 92a approaches the left end of the part 92e of the slot, causes a stop 112 fixed on the shaft to abut a slide 111 and pull a chain 110 to raise the arm 68 which unlocks the door. In this position of shaft 95 the door is free to be moved by a prisoner. The shaft 95 may control a series of similar doors.