GB1455256A - Devices for holding open doors - Google Patents

Abstract

1455256 A device for holding a door open; releasable fastenings NEWMAN-TONKS Ltd 16 Jan 1974 [17 Jan 1973] 2369/73 Headings E2A and E2X A device for holding a door 10 open comprises an electro-magnetic catch 13 which is arranged to be engaged when the door reaches its fully open position to hold the door open, and an electrical delay circuit which is arranged to release the magnetic catch after a predetermined time delay so that the door can close. As shown, the catch is secured to a wall 12 and a keeper plate 14 is carried by the door 10. The catch, Fig. 3, comprises a spherical body 17, which is mounted by screws for selected universal, locking, adjustment in a cover plate 16 of a casing 15 so as to accommodate the angle of the keeper plate 14 when the door is opened more than 90‹, Fig. 2 not shown, and which houses a plunger 19 which is urged outwardly by a spring to be pressed inwardly when engaged by the keeper 14 to actuate a switch 19a. The latter connects electrical power to the electromagnet through a time delay, Fig. 4 not shown, which ensures that the door is held open for a predetermined period. After this period the time delay, which comprises a cover (23) and a casing (22) which contains a printed electrical circuit (24), de-energises the electro-magnet so that the door closes. An electro-magnetic catch (25), Fig. 5 not shown, is adapted to be secured to the floor by screws (26). An electrical circuit for the electro-magnet and timing device, Fig. 6 not shown, comprises a supply (29), which has a common earth, at (32), with the casings of the timing device (21) and the magnet (15), and which leads through a terminal block 36 to the plunger switch (19, 19a) and a variable resistance (28) for regulating' the delay of the timing device. In a modification, Figs. 7, 8 not shown, a unit (41), containing the plunger and plunger switch (38), is separated from the wall-mounted electromagnet (39). The timing device can be included in the electrical supply circuit of an electric motor for opening the door. In a further embodiment the catch is contained in a casing mounted along the top of the door frame, the keeper, slidably mounted in the casing, being actuated by the linkage of a door closing unit when the door is fully open.