GB236783A - Lock for the doors of railway carriages and the like - Google Patents

Abstract

236,783. Kiekert, F. W. Oct. 17, 1924. Latches, sliding; locks, square-key; striking plates for latches.-A latch-bolt which is held half-shot by a pivoted trigger when the door is open, is controlled by a three-armed follower on the handle spindle, one arm engaging a recess in the latch bolt, a second arm engaging the boltshooting spring, and the third arm co-operating with the trigger to hold the bolt half-cocked. Fig. 6 shows the mechanism with the door open and the latch bolt 1 held within the casing. On closing the door, the end 7 of the trigger pivoted at 8 hits the projection 22 in the recess 21 of the striking plate 18 and rocks the trigger against its spring 10 to release the trigger arm 9 from the path of the follower-arm 4. The spring 15 mounted on the plunger 13 sliding through the flange 14 then pushes the plunger-head 12 upwards, the pin 11 engaging the hooked-arm 5 of the follower to rock the follower, causing the arm 3 to shoot fully the bolt 1 as shown in Fig. 1. For retraction, the handle spindle 24 is turned when the arm 3 retracts the bolt against the spring 15, and on opening the door the trigger tilts back under the influence of the spring 10 and engages the arm 4. The bolt has an auxiliary spring. In thin locks for metal doors such as shown in Fig. 8, this auxiliary spring 29 is mounted in a casing 28 outside the lock casing and engages a peg 30 on the bolt. The striking plate is of the form shown in Fig. 1, a bevel 20 leading to the latch bolt recess 19 and a recess 21 having a projection 22 to engage the trigger. A recess 23 is provided for the lock bolt 16 which is operated by a cam 17 turned by a squared key. The cam has two flat edges engaging with a flat spring to hold the cam in either of its extreme positions.