Patent GB-903664-A (GB)
Title: Door closer assembly
IPC: E05F3/04
Filed: 1961-04-20
Abstract: 903,664. Door closers. RIXSON CO., OSCAR C. April 20, 1961 [April 20, 1960], No. 14288/61. Class 65 (1). In a door closer having a door carrying spindle 3 (Figs. 5, 6) rotatably supported vertically in a casing 1 and a torsion-spring 31 secured at one end to the casing and pivotally connected at the other end to one end of a linkage 39, 41 pivoted in turn to a crank-plate 43 carried by the spindle, the outer edge of the crank-plate forms a cam surface having a stop 51 which is engaged by a spring- biased pivoted follower arm to hold the door in its open position. Means are also provided for selectively holding the follower arm in an inoperative position out of contact with the cam surface. The follower arm comprises a pair of arms 67, 69 (Figs. 12, 13) pivoted at 65 on either side of two symmetrical baseplates 57, 59 secured to the casing 1, a cam follower roller 72 being pivoted on a pin 71 between the extremities of the arms. A bar 81 which has an aperture 98 pivotally engaged with lugs 95, 97 on the arms, is slidably guided between a pair of ears 77, 79 extending from the plates 57, 59 by a pin 82 passing through a slot 99 and carries the springs 89, 91 which bias the arms and which act, respectively, between the arms and the ears and between an enlarged central portion of the bar and supporting brackets 73, 75 on the plates. The bar 81 and the arms 67, 69 are rendered free to follow the cam surface or are retracted therefrom by an eccentric selector cam 111 which is rotatably mounted in apertures 105, 107 in the ears 77, 79 and engages in an aperture 103 in the bar. The cam is rotated by turning a slotted head 113 (Fig. 5) recessed into the top of the casing and connected to the cam by an hexagonal shaft 112. The extent to which the door can open is limited by the engagement of the stop 51 with abutment surfaces 58, 60 on the plates 57, 59. In a modification (Fig. 15) the follower arm comprises a bell-crank 179 loaded by concentric springs 184, 185 and rendered inoperative by a selector crank 190 turned by a rod 191. Damping mechanism.-The damping mechanism comprises a cylinder block 116 (Figs. 4, 8a, 9) having cylinder bores 119, 121 of different sizes containing pistons 123, 125 pivotally connected by arms 127, 129 to opposite sides of a crank-plate 117 carried by the spindle 3 so that the pistons move in opposite directions when the door is opened or closed. During the opening movement of the door the smaller piston 125 moves towards the closed end of the cylinder 121 and the hydraulic fluid is expelled from the cylinder through a tapering V-shaped slot 146 in the cylinder wall, which extends from the open end of the cylinder for about three-quarters of the cylinder length, and through a passage 147 in the closed end of the cylinder which is controlled by an adjustable needle valve 148. The smaller piston consequently provides a damping action which increases as the door approaches its fully open position. When the door begins to close the piston 123 begins to move towards the closed end of the cylinder 119 and the hydraulic fluid, which entered the cylinder through a non-return valve 151 in the piston during the opening stroke, is expelled through a passage 152 in the cylinder wall controlled by an adjustable needle valve 155. When the door reaches a point about 15 degrees from its fully closed position the forward end of the piston 123 covers the passage 152 and its rearward end uncovers a passage 159 (Fig. 8a) which, together with passages 157 and 158 controlled by an adjustable needle valve 160, forms a by-pass to the piston. The speed of the final or latching portion of the door closing movement can thus be controlled independently by the valve 160. During the closing of the door hydraulic fluid flows into the cylinder 121 through a non-return valve 141 in the cylinder wall.