GB784812A - Latch mechanism - Google Patents

Abstract

784,812. Door locks; latches. FERRO STAMPING CO. Oct. 24,1955 [Feb. 7, 1955], No. 30316/55. Class 44 A latch mechanism comprises a rotor having both a toothed latching wheel and latching lobes, a wedge cam being resiliently urged into the space between a fixed abutment and the latching. lobes, and means for moving the cam to release the lobe engaged thereby and allow rotation in the unlatching direction. The latch comprises a rotor having teeth 12, Figs. 1, 6, co-acting with a rack 22 on the door frame, so that as the door is closed, the rotor rotates anti-clockwise. The rotor also has lobes 30. Fig. 1, which co-act with a cam plate 78 loosely pivoted at 80. and having an arcuate slot 82 through which protrudes a fixed bolt 84; the plate 78 is urged clockwise by a spring 86. As the rotor turns anti-clockwise, the surfaces 94 of the lobes 30 bear on the cam surface 92 and rotate the plate 78 clockwise, the spring 86 tending to turn the plate 78 anticlockwise, so that when the door ceases moving, the portion of the plate 78 below the bolt 84 acts as a wedge to hold the rotor against clockwise rotation and thus prevent the door opening. Release of the door to addow opening may be obtained by clockwise rotation of plate 78 by moving the flange 90. Further means for releasing the latch comprise a lever 100, Figs. 2 4, pivoted at 102 and bifurcated, one bifurcation having a projection 104 movable into, the path' of a hook portion 106 on plate 78 so as to hold plate 78 against clockwise movement, and the other bifurcation 110 adapted to hook over-the plate 78 and move it clockwise to release the latching mechanism. The lever 100 may be actuated by mechanism attached to an elongated slot 112 or by a lever 72 attached to bifurcation at. 108, and released for actuation by a keyoperated lock 70. The latching teeth 12 are preferably helical and are associated with inclined teeth 22, Fig. 7, on the keeper plate 16; this arrangement resists relative movement in the direction 118. The angle of inclination is preferably between 30 and 60 degrees.