Patent GB-257509-A (GB)
Title: Improvements in or relating to pressure-operating systems for the protection of strong room doors and the like
IPC: E05B51/02
Filed: 1925-03-23
Abstract: 257,509. O'Brien, M. C. M. March 23, 1925. Safes and strongrooms; pneumatically controlled fastenings; fastenings co-operating with alarms; obstruction bars; multiple-bolt fastenings.-A pressure-operated locking system is arranged with a pawl or swivel bar which, when pressure has forced bolts into operative position, prevents withdrawal of the bolts when the pressure falls. In the embodiment illustrated, pressure is admitted to the pressure engine 320 through the pipe 319 and to the cylinder 318 through the pipe 316, when the valve 313 is opened; the spring valve 317 being normallyopen. When pressure accumulates in the engine 320, the bracket valve 333 is forced to the bottom of the, cylinder 320<a> rotating the shaft 330 by a cord 332 and pulley 331, causing the lever 334 to press down the pawl arm 335 raising the other end 336 clear of the bolt 326. Pressure being simultaneously admitted to cylinder 318, the piston 324 is forced along the cylinder 318, forcing the bolt 328 into its socket 308. The valve 322 being closed, the escape of pressure past the bucket valve 333 gradually equalizes the pressure at each side and the bucket valve gradually returns to the top of its stroke by the force of the weight 337 on the side of the pulley 331. As the bucket valve rises, the lever 334 is raised from the pawl arm 335, allowing the pawl arm 336 to drop into the notch 329 to hold the bolt in its shot position. To withdraw the bolt, the valve 322 is opened, allowing pressure on the underside of the bucket valve to escape so that the valve is forced downwards revolving the shaft 330 and causing the arm 334 to trip the pawl 335. When the pawl is clear of the bolt, the valve 313 is closed, cutting off the supply of pressure to the cylinder 318 so that escapement past the bucket valve 333 reduces the pressure behind the bolt allowing the spring 325 to retract it. A pipe 339 carries pressure to the locking devices on the same or other doors, a spring retracted piston 340 operating one end of an obstruction bar 307 against a spring 309, a locking pawl 346 being provided and released by hand. The pipe 339 is fitted also with a suitable alarm. In the case of a safe door, double bolts are provided, which cannot be simultaneously operated. The cylinders 128, 128<a> carry pistons 129 retracted by springs 130 when not forced forward by pressure, and carrying bolts 132. 132<a>. When the knots 137, 137<a> are pulled out, the cylinders are under pressure, and when pulled out, the cylinders are cut off from pressure. The depressions 145, 146 and hump 148 of the bolt 132 are so arranged in relation to the swivel bar 141, and the depressions 143, 144 and hump 147 of the bolt 132<a> that simultaneous forward and backward movement of the bolts is impossible. To withdraw the bolts, the knot 137 is depressed, cutting off the cylinder 128<a> and opening the exhaust pipe 135, allowing spring 130 to force back the piston 129, and bolt 132<a>. The depression 144 now in alignment with the swivel bar 141 and the knot 137 is depressed, the knot 137<a> being kept depressed, to permit spring retraction of the other bolt. The pipes may be embodied in the safe walls.