Patent GB-656010-A (GB)
Title: Improvements relating to devices for opening and closing gates and doors automatically
IPC: B62D33/03
Filed: 1948-12-31
Abstract: 656,010. Door and gate operating-apptiances. KEMP, J. V. L., and CRAIG. G. L. Dec. 31. 1948, Nos. 33570/48 and 14521/49. [Class 65(i)] In mechanism for opening and closing a door or gate a spring is held between two relatively movable members, being stressed during the initial part of the opening movement and thereafter serving to complete this movement, and one of the members moves along a different path during the closing movement so that there is no increase in spring stress during such movement, the force for producing the dosing movement being provided by release of residual stress in the spring or by a second spring which is stressed during the opening movement. A delay mechanism may be embodied for holding the door open for a predetermined period. As shown in Fig. 3 a rod 13 is pivotally mounted at one end on a gate post and its other end, which projects into a box 12 carried by the gate, is provided with a roller 14. The latter is biassed downwardly by a cable 15 attached at its respective ends to a member 16 slidably disposed in the box and to a tension spring anchored to the gate post. Initial movement of the gate from the closed position displaces the roller upwardly upon a triangular plate 18 thus stressing the spring until the roller passes the apex 18a, when the spring draws the roller down the opposite incline to complete the opening movement, the roller then resting upon a sliding stop 20 connected to the plunger of a spring-loaded dashpot 22. Upon collapse of the plunger under the pressure of the spring the roller returns along a plate 19 to its original position, so closing the gate. A pivoted latch 24 prevents the roller moving in the wrong direction. The opening of the gate is initiated by pressure of a vehicle either against a bumper bar mounted on one side of the gate and moveable relatively thereto to operate a latch mechanism, or against a collapsable pillar on the other side of the gate and connected to the bumper bar. In a modification the roller is biassed by a torsion spring into contact with a triangular track located within a cylinder carried by the gate, the roller being carried by a member rotatably mounted on the rod. In a further modification, Fig. 13, the mechanism comprises a spring-loaded toggle, one arm 29<1> of which is supported by a pivoted stop 20 actuated by the plunger of a dashpot, and the other arm 30 of which is telescopic and is biassed to extend by a compression spring 34. On opening the gate the pivot 31 between the arms follows a track 38a, and the toggle, after moving to deadcentre position against the action of the spring, is carried by the latter to the gateopen position shown. The gate remains open until the stop 20 has tilted so as to allow the arm 29<1> to slide past it, thus freeing the gate for closing under the action of a second spring 37, the pivot 31 returning along a track 38b. The Provisional Specifications state that the gate may be of the self-closing type when no closing spring is required, that the roller may be held against the incline by means of a weight, and that the gate may be operated remotely by mechanical connections to a hand lever or by a connection to another gate.