802,335. Door chains; lockable latches. REINER, T. Feb. 29, 1956, No. 6376/56. Class 44 A door lock comprises portions A and B adapted to be mortised in a door and door jamb respectively, a guard chain 106 freely movable through chain guide means 102, means 106 yieldingly urging the chain inwardly into the portion B, means 109 for limiting outward movement of the chain, coupling means 51 fixed to the outer end of the chain, a strike plate 37 having a recess formed therein and extending to the edge thereof (Fig. 2, not shown), this recess permitting passage of the coupling means therethrough, the guide means 102 being disposed behind the recess and providing a seat within the door jamb for the coupling means. door latch means 27 and chain latch means 48 included in the portion A the door latch means being adapted for latching engagement with the strike plate, and the chain latch means being arranged for passage through the edge portion of the recess for latching engagement with the coupling means, and manually operable unlatching means included in the portion A and selectively actuable either to retract the door latch means alone for limiting opening of the door or to retract both the door latch and the chain latch means together for permitting the door to be fully opened. The door latch 27 comprises upper and lower legs 28, 29 interconnected by a bridge 30 and provided with guide flanges 31, 31a respectively and sloping surfaces 32, 33. The latch 27 is biased outwardly by a spring 41 secured to a pin 44 carried by latch 27. The legs 28, 29 of latch 27 straddle a guide block 39 fixed to an inner lock plate 14. The guide block 39 projects laterally beyond an end plate 10 where it is provided with a rectangular aperture defining a guard member 40. The chain latch member 48 is slidably disposed in a horizontally extending groove 47 in the guide block 39. a projecting edge portion 49 of the member 48 having a rectangular notch 52 formed therein. A master unlatching lever 53 is received in this notch 52, the upper end of the lever 53 engaging a shoulder 56 defined by a recess 55 in the upper leg 28 of latch 27. The lever 53 is pivoted at 57 to the rounded free end portion 59 of a lock tumbler plate 60. Springs 61 and 62 urge the lever 53 and tumbler plate 60 respectively in a clockwise direction in Fig. 1. A key operated bolt 65 is adapted to engage in an opening 100 in the portion B. The inner end of bolt 65 is slotted and guided for horizontal movement by a pin 68 mounted on plate 14 and pivotally carrying a series of conventional tumbler plates 69. Leaf springs 71 urge these plates 69 in a clockwise direction. For operating the lock from the inside a rotary member 75 is provided with a square hole 77 adapted to receive a square section operating shaft on which a door knob is mounted. The rotary member 75 has an upwardly extending leg 84 the free end of which is adapted to engage a downwardly extending projection 85 formed on the inner end of leg 28 of latch 27. Counterclockwise rotations of member 75 thus moves latch 27 to the left, master lever 53 remaining undisturbed. A lever 88 pivotally connected at 90 to ears 87 formed on the rotary member 75 is provided with a hook 91 engageable with the lever 53. Clockwise rotation of member 75 thus causes counter-clockwise rotation of lever 53 on pin 57 thereby drawing chain latch 48 to the left. At the same time the upper end of lever 53 engages the shoulder 56 and draws the door latch 27 to the left. Rotary member 75 is provided with vertically aligned feet 80 which engage a downwardly extending spring portion 81. The lower end 92 of lever 53 is adapted to be engaged by a key inserted into a key hole 72 when bolt 65 is fully retracted, but is held out of the way whenever the bolt is extended. For this purpose tumbler plate 60 is provided with a shallow slot 94 in which a dog 73 projecting laterally from the bolt 65 engages as shown in Fig. 1. When the bolt 65 is either half-way or fully extended the dog 73 is received in either of two deep slots 95 in the tumbler plate 60. The coupling member 51 has spaced ears 115, 117 defining a slot 122 adapted to receive the outer end of guard member 40. The ear 115 has a rectangular aperture 118 adapted to receive the end of chain latch 48, the outer end of ear 115 being rounded to facilitate latching engagement. A shallow rectangular notch 123 formed in the chain latch 48 prevents withdrawal of the latch 48 from coupling engagement with the member 51 whenever the door is opened with the guard chain 105 connected to the latch 48. Operation. The door may selectively be opened from the inside with or without - the guard chain 105 connected by turning the door knob in a counter-clockwise or clockwise direction respectively as viewed in Fig. 1. The door may be bolted in the usual manner by means of a key. When the key is used to open the door it may operate to retract the bolt 65, and turning of the key in the unlocking direction with the bolt 65 in its fully retracted position will simultaneously retract both the door latch 27 and the chain latch 48 so that the door opens freely.