Patent GB-747575-A (GB)
Title: Improvements in or relating to latch mechanism
Inventor: RAYBURN ALDEN GRANVILLE
IPC: E05C1/16
Filed: 1953-09-14
Abstract: 747,575. Door latches. CARTER, V. M. Sept. 14, 1953, No. 25298/53. Class 44. [Also in Group XXIV] A latch set for a door includes a cage 10 comprising two housings 20, 21 fitting one over the other and each having an aperture 25, 64 through both of which a latch housing 11 extends to be locked in position by relative rotation of the housings. As shown, the invention is applied to a mortice latch and the housing 11, Figs. 3, 7, which contains a latch bolt 15 is arranged at right angles to the cage 10 which rotatably supports operating spindles 45, 46. The housings are of cylindrical cup-shape each having a spindle boss 24, 63 protruding from its base. The housings are notched so that bosses 68 on the housing 11 can pass through the apertures 25, 64 which are in the cylindrical walls, the relative rotations of the housings 20, 21 closing the notches so that the housing 11 cannot be withdrawn. The rotation of the housings 20, 21 brings apertures 37 in the base of the inner housing 20 into alignment with corresponding apertures in the base of the outer housing 21, threaded sleeves 76 being passed through the apertures 37 to engage bolts passing through the apertures in the housing 21 to prevent rotation of the housings. The sleeves and bolts also engage escutcheon plates 72, 73 by which the housings 20, 21 are fixed to the door. The ends of the sleeves and bolts are concealed by rosettes 80, 81 which are sprung on to the escutcheon plates. Within the cage 10 formed by the housings 20, 21 is a pair of discs 26, 27, Fig. 6, which are connected together by a piece 28. The discs are locked relative to the inner housing by a boss 33 on the disc 26 which engages an aperture in the housing. Each disc has an arcuate slot 29 through which the end of one of the spindles 45, 46 passes. The spindles are each made of metal sheet rolled to cylindrical shape but having a longitudinal slot 47 and each is prevented from axial movement relative to its disc by abutments 49, 51, which engage one on each side of the disc ; the abutment 49 is initially passed through a notch 30 in the slot 29 and in use the spindle is not rotated far enough for the abutment to come opposite the notch. One end 48 of each spindle is of arcuate shape and engages the door latch actuator 16. Each spindle receives a knob 12<SP>1</SP>, 13<SP>1</SP>, the boss of which fits over the spindle ; each knob is locked in place by a projection 56, Fig. 5, on a resilient ring 54 contained in the spindle, the projection passing through aligned apertures in the knob and spindle. If desired a privacy latch may be provided to prevent when necessary the door latch from being operated from outside the room (by the knob 12<SP>1</SP> in Fig. 7) but allowing it to be operated by the inside knob 13<SP>1</SP>. This privacy latch comprises a push-button 90 urged to the right as shown, by a spring 100 and connected to a bar 92 which passes through slots 31, 32 in the discs 26, 27. When the push-button is pressed, the end of this bar engages the slot 47 in the spindle 45 and prevents .its rotation. The bar is locked in the engaged position by a lever 97 which is pivoted to it and the free end of which is urged away from the bar by a spring 106 so that a detent 105 can engage a shoulder 108 on a ring 101 mounted inside the spindle 46. The detent 105 is released by rotating the knob 13<SP>1</SP> so that the shoulder 108 rotates away from the detent. So that, if need be, the door can be opened from outside when the privacy latch is preventing the rotation of the knob 12<SP>1</SP> a spindle 91 is provided, this is connected to a bushing 118 in the knob 12<SP>1</SP>, the bushing having a slot 120 so that it can be rotated by a screw-driver, key or the like. The spindle 91 is connected to an arcuate latch actuator 116 which extends through the spindle slot 29 to engage the door latch actuator 16.