Patent GB-927256-A (GB)
Title: Locking devices
Inventor: MEANS CLARENCE HUGH
IPC: B64C1/30
Filed: 1961-02-03
Abstract: 927,256. Latches. DOWTY ROTOL Ltd. Feb. 2, 1962 [Feb. 3, 1961; June 23, 1961], Nos. 4203/61 and 22666/61. Class 44. [Also in Group XXXIII] A locking device comprises a lock bolt adapted for connection to a first member and a holding means for receiving the first member, the holding means including a fluid-pressure operated tensioning element for straining the lock bolt, and a mechanical locking member for mechanically locking the lock bolt in its strained condition. The invention is applied to the locking together of two parts of an aircraft fuselage in which a number of the devices is used and in the arrangement according to Figs. 1 and 2, in which a lock bolt 11 attached to one part 15 is engageable with a cylindrical member 18 attached to the other part 16, the tensioning element comprises a piston and rod 40, 42 into which the lock bolt 11 enters as the parts 15, 16 are brought together. Upon continued movement of the bolt, a chamfered face 54 thereon engages projections 47a on a ring 47 of locking spring claws which are loaded by a spring 49, the projections 47a finally engaging a chamfered face 53. Pressure fluid is then applied through a connection 67 to chamber 66 to displace a member 24 in a direction towards the bolt and also through a connection 64 to a chamber 63 which pressure imposes a tension upon the bolt 11 through the projections 47a and allows projections 22a on a ring 22 of spring claws to engage a chamfered face 44 of a projection 43 of the tensioning element whereby to lock the bolt.in tensioned position, in which position the member 24 has pivoted a lever 55 to the position shown in Fig. 2. The lever 55 actuates a spring-loaded plunger 59 which in the tensioned position of the bolt 11 allows manual operation of a lever 62 to release the fluid pressure from the chambers 63 and 66. When the parts are to be separated, pressure fluid is applied through a connection 65 to an annulus 27 to displace the member 24 against a spring 38 and at the same time pressure is momentarily applied to chamber 63 to cause the tensioning element 40, 42 to hold the tension in the bolt 11 to permit disengagement of projections 22a and outward movement of the bolt. All the levers 62 of the devices are connected together for operation in unison. In another arrangement, Figs. 3 and 4, in which a lock bolt 110 is arranged to be forced out of the first part 124 by a push-rod 150 as the parts are moved towards each other, the rod 150 operates on the bolt 110, which is spring-loaded, through a lever 115 which operates in a slot 117 in a cylinder 118 carrying the bolt. As the parts 124, 125 are brought close together the bolt enters a hollow piston-rod 133 of a piston and rod-tensioning element 132, 133, and a projection 112 on the bolt is engaged behind projection 146a of a ring 146 of locking spring claws. Fluid-pressure is then applied to chambers 129 and 157 through conduits 153 and 159 respectively to displace a member 137, Fig. 3, against a spring 142 to free a flange 137a of the member 137 from projection 140b of a ring 140 of locking spring claws. The fluid pressure in chamber 129 acts upon piston 132 to tension the bolt 110 through a projection 134 and projections 146a. Thereafter, fluid-pressure is applied to a chamber 156, the differential pressure between the chambers 156, 157 being then effective to move the member 137 such that the projection 134 is locked between projections 140b and 146a. A transverse locking member 149 is then positioned such that it locks the element 132, 133 with respect to the part 125 and the fluid-pressure applied to chambers 129, 156 and 157 can then be released. When the parts are so separated, fluid-pressure is applied to chambers 129 and 157 allowing the locking member to be released, fluid-pressure in chamber 129 is released and the parts moved away from each other, whereupon the lock bolt is retracted into cylinder 118 by its spring 119. The chamber 157 is then exhausted and the member 137 moves to the position shown. In a further arrangement, Fig. 6 (not shown), for a considerably shorter lock-bolt, applicable to either of the foregoing arrangements, a stack of Belleville washers is provided on the bolt to supplement the strain imposed by the tensioning element.