Patent GB-447635-A (GB)
Title: Improvements in multiple unit treadle controlled door system
IPC: G06C11/00
Filed: 1935-05-16
Abstract: 447,635. Door - operating apparatus. NATIONAL PNEUMATIC CO., 420, Lexing- ton Avenue, New York, U.S.A. May 16, 1935, No. 14399. Convention date, July 5, 1934. [Class 65 (i)] In an arrangement for operation of a door by treadles, a number of treadles are provided, one of them under the door, and the control arrangements are such that the door is opened only when a person approaches it over the treadles in succession, the door closing or remaining closed when a person moves away from the door over the treadles in succession. In the arrangements described, the treadles close electric switches which directly or indirectly control the electro-magnetic valve 10 of a differential fluid-pressure engine operating a pair of folding doors 1 ; the treadles are arranged so that adjacent ones are depressed together for a moment. In the arrangement shown in Fig. 5, a person approaching the door from the left depresses treadle A, energizing relay 33 to prepare circuits, for relay 34 and valve 10, which are completed by treadle B, relay 34 having a stick circuit so that the circuits are maintained when A is released and 33 drops. Treadle C completes a direct circuit for 10 ; release of B restores 34 to normal, and release of C de-energizes 10 for the door to close. The door is not operated by a person moving away, since B completes no circuit until A is operated, when the circuit is almost immediately broken again by release of B. Treadles E and F act in the same way in every case. In the simplest arrangement a single stick relay is used, treadle A or C closing a contact in the relay circuit for energization when B or D is depressed. In a modification, a relay having two windings is provided at each end of the arrangement, the end treadle, e.g. A, energizing the relay while the second treadle, e.g. B, energizes a holding coil through a contact of the relay and also energizes the valve 10 through a contact of the relay. If B is operated first, the relay is not energized until A is operated, when power is immediately cut off from 10 by release of B. In a modification of this form, the holding coil is replaced by a feed through a resistance to the operating coil, the resistance preventing operation of the relay by treadle B. In a further modification, the relay is energized only by A and B in series, B also completing a stick circuit and a circuit, including a contact of the relay, for valve 10. In another modification, using common relays for the two sides of the door, treadle A or E energizes one relay to prepare a circuit for energization of the second relay by treadle B or D to complete a circuit for 10 and a stick circuit for itself, the latter including B or D but being independent of the first relay. The arrangement shown in part in Fig. 9 prevents the momentary energization which is permitted by all the above arrangements when a person moves away from the door. A depressed first energizes the operating coil of 71 and the lower (holding-down) coil of 72 ; B then energizes the holding coil of 71 and, the upper coil of 72, which when A is released closes the circuit for valve 10. If B is depressed first, no circuit is made until A operates 71, and the lower coil of 72 then prevents any energization of 10. In another arrangement achieving the same object, Fig. 11, the end treadles are replaced by two treadles, such as J, K, and treadles B, D complete a stick circuit for relay 98 directly controlling 10. Relay 97 has an armature which can move either way from the position shown, with spring-pressed contacts 98<1>, 105. J energizes the operating coil through 98<1> to open 105 and close 120, and K then simply energizes the holding coil ; if K is operated first, the bottom coil moves 98<1> so that J cannot energize 97 but maintains this holding-down coil. In a modification, also using the divided end treadle, two relays similar to 84, 85 in Fig. 10 are provided at each end, each having an operating and a holding coil and each normally closing the operating circuit of the other. J operates, and K holds, one relay (84) which energizes the relay corresponding to 98 in Fig. 11 ; if K is depressed first, it operates, and J holds, the second relay (85) which thus prevents operation of the first. In all the above arrangements, if a person approaching the door steps on treadle J at the same time as a person leaving, the door will not operate ; to avoid this objection treadle J is further subdivided, the part J<1>, Fig. 10, being placed at one side so as only to be operated when two persons are passing one another at J. Section J<1> energizes relay 84 independently of 85, the operation being otherwise as described above. The Specification as open to inspection under Sect. 91 describes also arrangements in which the passage is divided into two halves, each used in one direction only and each having a single treadle, on the approach side but projecting past the door, the treadles being connected to individual or common control means. This subject-matter does not appear in the Specification as accepted.