Patent GB-627451-A (GB)
Title: Improvements in or relating to latch devices
IPC: E05C1/12
Filed: 1947-06-30
Abstract: 627,451. Latches. AUSTEN, C. J. June 30, 1947, No. 17212. [Class 44] In a latch for retaining a door or drawer in closed position a withdrawal member is provided which is separate from the latch bolt and is operable to withdraw the latter by energy stored during movement of the movable member, the withdrawal member being held by manually releasable stop means against movement by the stored energy. The latch bolt 23, Fig. 2, is mounted on a stem 24, and two loading members 25 are provided, one on each side of the latch, mounted on rods 26. The withdrawal member consists of a sleeve 27 within which the stem 24 slides. Rods 26 and sleeve 27 are guided in holes in a partition 28 in the lock casing, members 25 abut against a yoke 32 sliding on stems 24 and 26, and urged towards the front of the casing by springs 31. The sleeve 27 has an external circumferential rib 33 between which and yoke 32 acts a spring 34. Outward movement of stem 24 in sleeve 27 is limited by a washer 35 on stem 24. A spring 38 acting between the end 37 of the sleeve and a flange 41 on stem 24 urges the latch bolt outwardly relatively to the sleeve 27. A single longitudinal rib 42'is formed on the sleeve 27 between the end and the rib 33, and engages in a slot in partition 28 to prevent rotation. A stop member slidably mounted and operable by a push button 44, Fig. 4, comprises a plate having a notch 46 which in one position registers with rib 42, and in another position blocks movement of the sleeve, and being biased by a spring to the blocking position. The latch bolt 23, Fig. 2, is of the usual chamfered rounded form, the loading members 25 being similarly shaped. Striking plate 47 has a recess 51 to receive the latch bolt, and flat faces 52 against which members 25 bear. When the door is open, yoke 32 is held in its outermost position by springs 31, and latch bolt and members 25 are fully projected, and sleeve 27 is held against washer 35. As bolt 23 and members 25 are forced in by the striker in closing, springs 34 and 38, as well as springs 31, are compressed, since sleeve 27 is held by stop member 43. On complete closing, latch bolt 23 is forced into recess 51 by spring 38, the parts being then in the position of Fig. 2. To release the catch, stop member 43 is moved by pressing the push button, sleeve 27 is moved inwardly by spring 34, taking the latch bolt with it. As the door is opened, members 25 are again projected by springs 31 Figs. 5 and 6 show a modified form in which the latch is a pivoted member 63, the nose of which is undercut to engage the keeper 66, actuated by a spring influenced rod 71. The stop member consists of a pivoted arm 87, operated by a push rod and button. The action is similar to that of the first described form. In a further modification, Fig. 8, a withdrawal member 99 carries two pivotally mounted blocks 101, 102, through the latter of which passes the stem 103 of the latch 104, which is urged outwardly by a spring 107. Block 101 is bored for the passage of a rod 108 which forms the loading member. The withdrawal member 99 carries a weight 100 which is raised as the door is opened by the pull of a wire 124, one end of which is fixed to the door frame, while the other is secured to the rod 108. Member 99 is retained in position with the weight raised by a spring urged push rod 118, of which an enlarged portion drops into an enlarged part of slot 117. Manual operation of the push rod 118 releases the member 99, and the fall of weight 100 withdraws the catch.