Patent GB-1380955-A (GB)
Title: Door latch
IPC: E05B65/26
Filed: 1972-04-06
Abstract: 1380955  Latches J A TRUHON 6 April 1972 [7 April 1971] 15809/72 Heading E2A A door latch comprises inner and outer escutcheon plates 10, 12 adapted to be mounted against inner and outer faces of a door 16 in a position overlying an opening through the door, the outer plate 12 having a recess 24 therein adapted to project into the opening and a peripheral flange 22 surrounding the recess and adapted to overlie the outer face of the door around the opening, and an outer door operating handle 26 mounted in the recess 24 and normally disposed substantially wholly within the recess. The latter has a bottom wall 40 which is generally parallel to the flange 22 and a flat inner surface, a lock bolt 38 comprising a sheet metal stamping having a flat inner surface positioned against the inner surface of the wall 40 and supported thereon for reciprocation in a rectilinear path. The bolt has a projection extending from one end thereof in a direction parallel to the path of reciprocation of the bolt to beyond the recess 24 and a bolt nose 58 thereon adapted to engage with a door-frame-mounted striker 162 to retain the door in a closed position, the bolt nose being thick in relation to the flat sheet metal body of the bolt and projecting from the plane thereof towards the flange 22 and beyond the wall 40. The exterior handle 26 is operatively connected with the bolt to retract the bolt from the striker engaging position to a striker releasing position when the handle is operated. There is an inner handle 88 mounted on the plate 10 and operatively connected with the bolt to retract the bolt when the handle is actuated. As shown, the bolt 38 is formed with a slotted extension 48 engaged by a pin 50 projecting from the wall 40 and an extension 52 return bent to form the bolt nose 58 in which is secured a metal block 60; the nose is slideably guided in a guideway 64 formed in a lug 66 integral with the plate 12 and retained therein by a plate 68. The bolt is biassed to the projected position thereof by a spring 72 the free ends 76 of which engage ears 78 on. the plate 44. The wall 40 includes a boss 80 in which a stem 82 is rotatably -supported; the stem carries the handle 88, which is journalled in a boss 90 on the plate 10, and a follower 86 having rounded ends 94 and engaged in an opening 46 in the plate 44. Rotation of the handle 88 in either direction causes one of the ends 94 of the follower to engage the edge 96 of the opening 46 and retract the bolt against the bias of the spring 72. The handle 26, pivotally supported in the plate 12 and by means of a pin 28, has lugs 32 which are adapted to engage ears 36 on the bolt 38 which project through slots 42 in the wall 40 of the recess 24. Secured to the stem 82 is a cam 98 provided with opposed cam lobes 100 interconnected by a recess 102 normally engaged by a pin 104 mounted on a lock plate 106 disposed between the cam and the follower 86. A spacer bushing 110 around the stem 82 engages the sides of an elongated opening in the lock plate to slidingly guide the lock plate which is biassed in one direction by a spring 112; a guide slot 116 in the lock plate is engaged by a stud 120. The bolt 38 is formed with a slot 124 the axis of which is perpendicular to the axis of the slot 116 and parallel to the axis of reciprocation of the bolt, the slot having a transversely enlarged end of slightly greater width than the large diameter cylindrical portion 118 the stud 120, and the opposite end of the slot corresponding in width to the small diameter cylindrical portion 130 of the stud. The inner end of the stud is screwed in a non-rotatable sleeve 132 axially slideable on a guide sleeve 133 in which the barrel 134 of a key-operated cylinder lock is arranged. The sleeve 132 is formed with circumferentially extending slot 38 at one side thereof and having opposed axially inclined sides the slot being engaged by the pin 140 on the barrel 134. Axially spaced notches 150 on the sleeve 132 are adapted to be engaged by a spring biassed detent 152. A cam 156 is formed on the lock plate 106 and the slot 116 extends to the peak of the cam which in the normally retracted position of the lock plate laterally clears a flange 158 on the stud 120 and with the lock plate in this position, when the handle 88 is rotated, one of the cam lobes 100 engages the pin 104 to shift the lock plate to the left, Fig. 6, to cause cam 156 to engage flange 158 and shift the sleeve 132 to a position wherein the detent 152 engages the outer of the notches 150; the stud 120 is projected outwardly of the plate 10 so that the portion 118 thereof moves axially outwardly of the plane of the slot 124 and aligns the portion 130 of the stud with the narrower portion 128 of the slot 124. Continued rotation of the handle 88 causes the bolt to be completely retracted against the bias of the spring 72. If the stud 120 is in the depressed condition thereof the portion 118 of the stud is engaged in the wider portion of the slot 124 and prevents substantial retraction of the bolt by the handle 26. Insertion of a key into and rotation of the barrel 134 causes the pin 140 to engage one inclined surface of slot 138 of sleeve 132 and shift the stud 120 outwardly; with the door lock in the unlocked position rotation of the barrel causes pin 140 to engage the other inclined surface of the slot to shift the stud 120 to the retracted locked position.