Patent GB-1372179-A (GB)
Title: Releasable fastening device
IPC: F16B39/08
Filed: 1970-12-16
Abstract: 1372179 Fastenings VACTRIC CONTROL EQUIPMENT Ltd 29 Nov 1971 [16 Dec 1970] 59830/70 Headings E2A and E2B A releasable fastening device for preventing relative angular movement between two elements 10, 11 comprises a member 18 which is mountable on one element 10 so as to be movable axially between first and second positions relatively to the element but incapable of any substantial angular movement relatively to the element, and spring 19 for urging the member 18 towards one position, the member 18 being movable in use by means of an operating member to the other position, the member 18 and the other element 11 having interengaging portions to prevent angular movement between the member 18 and the other element 11 when the member is in one of its positions. The element 10 has a thread at one end portion which engages with an internal thread of the element 11. The element 11 has teeth 13 which engage with teeth 27 on the member 18 to secure the elements against relative angular movement. To secure the member 18 to the elements, a plunger 16 with a transverse aperture 16a and the spring 19 extending from a reduced portion of the plunger are inserted in a blind bore in the element 10 and depressed so that the aperture 16a aligns with lateral apertures 20 in the element 10. An actuating member 17 is inserted through one of the apertures 20 so that end disc portions 21 engage in the apertures. The member 18 is mounted on the element 10 so that pins 23 projecting from the disc portions 21 extend in opposed interior grooves in the member 18 which is then turned slightly so that the pins engage in a circumferential groove, a keyway 25 on the element 10 then aligns with a keyway 24a of the member 18. A key is inserted in the keyways to allow small angular movement. The member 18 is in the position which is nearer to the threaded end of the element 10. The operating member is a tool which is inserted into a recess 14 in the element 10 to depress the plunger 16 therein thereby causing the actuating member 17 to turn and thereby raising the member 18 to its other position. The tool is then rotated to screw the element 10 into the element 11. The tool is removed from the element 10 allowing the plunger 16 to rise thereby depressing the member 18 to the one position in which the teeth 13 and 27 engage and the elements are fastened together against angular movement. In a modification, two elements 31, 32, Fig. 2 are secured together against angular movement by a member 36 urged by a spring 37 to engage teeth 43 on the member 36 with teeth 42 on the element 31. The element 31 is screwed into the element 32 by a box spanner inserted in a head 41 of the element 31 thereby depressing the member 36. When the spanner is removed a spring 37 moves the member 36 to engage the teeth 43 thereon with the teeth 42 of the element 31. The two elements may be separately journalled for rotation. The end of the element 10 remote from the recess 14 may have a permanent magnet and the element 11 may form part of an aircraft engine housing communicating with oil passageways the magnet attracting and retaining metal particles in the oil flow. The modification may similarly have a magnet.