Patent GB-792818-A (GB)
Title: A fastening device
IPC: F16B5/02
Filed: 1955-10-04
Abstract: 792,818. Screw fastenings; nuts &c. ELASTIC NUT CORPORATION OF AMERICA. Oct. 4, 1955 [Oct. 13, 1954], No. 28231/55. Classes 44 and 89(1) A fastening device for securing an innermember 36 to an outer-member 38 comprises a bolt 10 and a self-locking nut 12 having lugs 26, 28, and a retainer 14 for the nut having an aperture 50 adapted for assembly to said inner-member, the aperture 50 being shaped so that the nut can enter the retainer when in a limited number of positions only, so that the nut when screwed on to the bolt can then be rotated by turning the bolt with the bottoms of the lugs sliding on the base 34 of the retaimer until the lugs engage side webs 56, 58 on the retainer, further turning of the bolt advancing the bolt through the nut. As shown in Figs. 2 and 3 the base 34 is secured directly to the inner-member 36 by rivets 44. The aperture 50 Fig. 7, has a pair of oppositely-positioned recesses 52, 54 through which the lugs 26, 28 pass when the nut is passed through the retainer. Overlying each recess is a finger 60, 62 which engages the lug as it is passed through the recess. These fingers are depressed by pressure on the nut and bolt' and ensure that until the nut is turned so that the lugs engage the walls 56, 58, a visible indication is given that the fastener is not secured, since the head of the bolt, which is normally received in a countersunk aperture in the outer-member 38 is protruded from the surface of the member by the fingers. The lugs 26, 28 each have a bevelled under-surface, which engage tlhe edges of the recesses 52, 54 and draw the two members 36, 38 together when the nut is rotated. The nut is made self-locking by providing it with a number of beams 24 which are offset towards the thread-axis, but other self-locking means may be provided. The aperture in the 38 through which \the bolt passes can be indented, as at 42, to engage the aperture in the member 36, which is larger than the aperture in the member 38 to enable the lugs of the nut to pass through. This indentation of the member 38 resists sheerforce. In a modification, a bevelled-bushing is positioned on the bolt between the nut and the under-surface of the member 38 to engage a countersunk enlargement of the hole in the member 36. When it is desired to release the fastening from the inside of the inner-member 36, the bolt is provided with an extension 76, Fig. 9, having two parallel surfaces which can be gripped by a pair of pliers. When it is desired that the holes in the two members shall be of the same size, the bolt is provided with a threaded-stem of reduced diameter as shown in Fig. 12, and the nut is small ehough to pass through the hole in the inner-member 136. The bolt is made captive to the outer-member 138 by a bevelled snap-ring 216. The snap-ring is housed in an annular recess in an unthreaded shank-portion 222 of the bolt, and 'when the member 138 is disconnected from the member 136 is protrudes from the recess to make the bolt captive on the member 138. When the nut is passed through the hole in the member 136 to engage the retainer, the bevelled-edge of the snapring engages the edge of the hole in the member 136 and is thereby compressed so that it can pass through the hole. In this construction the retainer is not mounted directly on to the member 136 but a shim 143 is interposed. The retainer is loosely retained in a square-portion of a pressurecap 146 which is riveted to the shim and member 136, and whidh prevents fluid from passing through the holes in the members 136, 138. Specification 490,743 is referred to.