Patent GB-1206778-A (GB)
Title: Extensible and retractable locking strut or stay construction
IPC: F16B7/10
Filed: 1967-11-03
Abstract: 1,206,778. Releasable fastenings. NORCO Inc. 3 Nov., 1967 [25 Nov., 1966], No. 50211/ 67. Heading E2B. An extensible and retractable, locking strut or stay construction comprises, in combination, a pair of inner and outer, elongate telescoping members 10, 12 which are slidable one within the other to bring cooperable end portions thereof in proximity when the strut or stay is axially extended, said members having means 18, 20 at their remaining, remote end portions for attachment respectively to structural parts whose relative positions are to be controlled, said outer member 10 having in the wall of said cooperable end portion thereof, slot 22 extending therethrough, said inner member 12 having, in said cooperable end portion thereof, an outer annular fastening recess 24 comprising shoulders in its outer surface, an arcuate fastening dog 28 disposed in the slot of the outer member, said dog having an inner peripheral portion adapted to fit into said fastening recess of the inner member against the shoulders thereof to restrain movement of the inner member when the strut or stay is axially extended and the cooperable end portions are juxtaposed, a locking sleeve 34 slidably mounted on the outer member and enclosing the slot and fastening dog, said sleeve being movable between a locking position wherein it blocks said fastening dog to prevent its outward movement from the fastening recess, and a releasing position wherein it frees the dog for radially outward movement and for disengagement from said fastening recess and shoulders thereof, spring means 36 located within and biasing the looking sleeve to said locking position, said outer member having a rigid internal annular shoulder adjacent the slot thereof and facing away therefrom, said inner member having a rigid outer shoulder (provided by a member 48) at its said cooperable end portion, facing toward the fastening recess thereof and engageable with the internal shoulder of the outer member when the strut or stay is axially extended, to prevent separation of the two members. In the construction shown there are two dogs 28 diametrically oppositely disposed and the member 12 has a plurality of recesses defined by grooves between ribs 26 which provide the shoulders. Each dog has teeth which engage the grooves. The means for attachment to structural parts are screw threaded holes in the end portions of the members 10, 12. In a modification the recess is provided by the groove of a screw thread and the dogs are suitably modified. In the construction shown the portion of the member 10 having the slots for the dogs is attached to the remaining portion of the member 10 by a screw threaded connection and its inner end provides the internal shoulder. In another construction the two members each consist of a tubular portion and two end portions, the end portions each being provided with annular recesses into which the wall of the tubular portion is deformed by rolling so that rolled in grooves are left in the tubular portion at each end, one of the rolled in grooved constituting the recess for receiving the fastening dogs in the fastening condition. In this construction there are three dogs and the inner portion of each dog conforms in shape to the shape of the rolled-in groove. In this construction also the locking member has a frusto conical inner surface and the outer surfaces of the dogs are conic sections whereby the locking member forces the dogs inwardly so that in the fastening position there is no free play.