Patent GB-784054-A (GB)
Title: Improvements relating to locking mechanisms
Inventor: LOBELLE MARCEL JULES ODILON
IPC: B64F1/08
Filed: 1955-03-15
Abstract: 784,054. Automatic catches; electrically operated fastenings; hooks. M. L. AVIATION CO., Ltd. March 5, 1956 [March 15, 1955], No. 7549/55. Classes 44'and 89(2) [Also in Groups XXI and XXXIII] In a mechanism for releasably holding a movable member in which a force necessary for holding the mechanism in a locked position is resisted by one arm of a pivoted lever the latter is prevented from turning about its pivot by engagement of the tip of a second arm of the pivoted lever with a shaft, the shaft being rocked to release the mechanism by a relatively smaller force exerted by one of two solenoids acting one on each end of a yoke extending-symmetrically on both sides of the shaft, to bring a slot in the shaft into register with the tip of the second arm so that the pivoted lever is allowed to turn. In the arrangement according to Fig. 1, as applied to a glider or target towing release, a ring 2 attached to a towing cable is carried by an arm 3, which is pivoted to a casing 1 of the mechanism and is retained by a pivoted catch lever 8. The lever 8 is retained in the position shown, by a toggle linkage 10, 11, and a pivoted lever 15 which is pivotally connected with the toggle by a lever 13, and a tip 24 of which bears on a flattened portion of a shaft 17. The shaft 17 is rotatable by either one of two solenoids 19 and 20 which are operatively connected to a yoke 18 attached to the shaft 17, the arrangement being such that operation of either solenoid rotates the shaft 17 to bring a slot 23 therein into register with the tip 24 of lever 15 which is thereby rotated by a spring 25 in a clockwise direction, thus to collapse the toggle 10, 11 and free the ring 2. The. mechanism is reset by returning the lever 3 to the position shown, and rotating lever 15 by means of a cocking lever 27, the shaft 17 being returned to its original position by a torsion spring 17a acting between the casing 1 and the yoke 18. The mechanism may also be released on the. ground by means of a button 29 after the release of a safety catch 29a, the button being connected through a rod 30 with a member 33 which engages and moves an armature 22 of the solenoid 20. In another arrangement, Figs., 2 and 3, in which a load to be released is attached to a plug 51, the latter is retained by a pair of pivoted jaws 55, 56 coupled together by toggle links 60, 61 which are also pivotally connected through a link 63 to one arm of a pivoted lever 65, this arm and the link 63 forming a second toggle. The other arm of the lever 65 which is loaded by a spring 69, engages by its tip 70 with a shoulder 71 on a latch 72 pivoted to the casing of the mechanism. The latch 72 is connected through a rod and linkage 74 to one arm of a pivoted lever 77, the tip 79 of the second arm of which engages a rotary shaft 80 as in the previous embodi- The rod 74 extends through a partition 75 in the casing and is sealed by a bellows 76, the compartment on one side of the partition thus being sealed from that on the other side of the partition. The plug 51 is released from the jaws 55, 56 by operation of either one of a pair of solenoids 81, 82, the tip 79 of the lever 77 then engaging a slot 84 in the shaft 80 and thereby collapsing the toggles 63, 65 and 60, 61. The mechanism is reset by inserting the plug 51 into the aperture 85 of the casing and rotating a cocking handle 86 in an anti-clockwise direction to restore the mechanism to the condition shown in Fig. 2. The mechanism may be released manually by means of a plunger 89 which operates against a spring 90 against the yoke 83. The plunger 89 is covered by a resilient dome, and a union 92 for cables to the solenoids incorporates a water-tight gland. In a further arrangement, Fig 5, in which a load carrying plug 102 is retained by a pair of pivoted jaws 106, 107, connected to a toggle linkage 110, 111, the links 110, 111 are pivotally connected to a cross-head 113 which is slidable in a guide 114. The cross-head 113 is connected through a second toggle linkage 115, 116 and a link 118 to one arm of a bell crank lever 119 pivoted at 120 and the other arm of which is loaded by a spring 121. A lug 124 on a latch 125 engages a lug 126 on the bell crank lever to maintain the mechanism in the locked condition The latch 125 is pivotally connected through a rod 129 to a lever 132, a tip 134 of which engages a shaft 135 which is rotatable by either one of a pair of solenoids 137, 138. As in the other arrangements the mechanism is released by operation of either of the solenoids and the latch 125 is then rotated to release the bell crank lever 119 to allow collapse of the toggles 110, 111 and 115, 116. The mechanism is reset by means of a rod 141, which, after re-insertion of the plug 102 is moved inwardly to rotate the bell crank lever 119, the latch 125 being rotated in an anti-clockwise direction by the lug 126 until the latter is engaged by the lug 124. The shaft 135 is returned to its locking position by a torsion spring 135a. The mechanism may be released manually by means of a plunger 143 which acts through a lever 145 on a plunger 147 engaging a yoke 136 attached to the shaft 135. As in the previous arrangement, the housing for the mechanism is partitioned, a part above the partition 130 being watertight and being provided with a desiccator. Specification 548,203 [Group XXI] is referred to.