Patent GB-1211879-A (GB)
Title: Improvements in and relating to mechanism door latch apparatus
Inventor: MCBURNIE S G
IPC: E05C1/16
Filed: 1967-12-20
Abstract: 1,211,879. Catch fastenings. VELTO INDUSTRIES Ltd. 20 Dec., 1967 [3 Jan., 1967], No. 57809/67. Heading E2A. [Also in Division F2] Mechanism for door latch apparatus for a door having a first hole 30 extending therethrough from face to face thereof and near one of its edges and a second hole 31 therein extending from and normal to the first hole and opening out through said door edge, comprises a longitudinally adjustable housing 44, adapted to be placed in the first hole and extending through the door, end flanges 48, 54 on the housing at opposite ends thereof and extending normal to the axis of the housing, said flanges being adapted to engage the opposite faces of the door properly to position the housing in the first hole with said axis extending normal to the faces, a shaft 60 extending longitudinally through the housing and through openings in the flanges, means 80, 81 secured to the shaft near the end flanges cooperating with said flanges to retain the shaft in position, a plunger 70 adapted to extend through the second hole 31 and a hole in the housing and mounted for longitudinal movement along an axis normal to the longitudinal axis of said shaft, and interconnecting means 72 between the plunger and said shaft and shaped to cause the plunger to move longitudinally upon rotation of the shaft in either direction. In the construction shown the housing consists of an outer sleeve 45 and an inner sleeve 46, the two sleeves having screw threads by which they are connected together; the flanges of the sleeves are both provided with depressions 50, 56 and for each the end portion of respective handles 80, 81 engages in the depression so that the handle is located relative to the flange. The shaft 60 has four radial ribs 61 extending from end to end of the shaft and disposed at 90 intervals circumferentially and on the edges of the ribs at each end portion of the shaft are interrupted screw threads 63 on which the handles which as shown are internally threaded are secured. The inside handle 80 is prevented from rotation relative to the shaft by a lock washer 93 which has a cross shaped opening 94 which conforms to the cross sectional shape of the shaft; it has a number of circumferentially spaced and inwardly projecting tabs 95 provided on the outer edge and the base 84 of the handle has a similar number of slots 96 of corresponding shape and spacing, the washer 93 fits over the end portion of the shaft and seats against the base 84 of the handle with the tabs 95 lodged in the slots 96. The washer has a pair of small handles 97 by which it is insertable and removable. The outer handle 81 is secured to the shaft by means of a key 90 which is square in cross section so that the key fits between two adjacent ribs on the shaft with an edge portion of the key entering a notch 91 in the handle. Both of the handles have detachable end discs 104, 105 to enable the lock washer and key to be inserted, the discs being sprung in place. The shaft 60 has notches 64 in the two vertical ribs 61 and the  horizontal rib on the same side as the notches has a notch 65 which is aligned with the notches 64; the interconnecting means 74 consists of a yoke 72 with arms 73 which extend over the vertical ribs 61 and it has a recess shaped to enter the notches 64 and 65. A latch plate 20 is integrally formed with spring 28 and it is pivoted in a supporting frame 21 which is inlaid in a recess in the edge portion of the jamb 16.