GB1107756A - Improvements in fasteners - Google Patents

Abstract

1,107,756. Moulding fasteners. ITW Ltd. 18 Feb., 1966 [18 Nov., 1964], No. 46964/64. Heading B5A. [Also in Divisions E2 and F2] A fastener formed from a resilient mouldable material comprises a head 4, a tubular shank 2 extending from the head and having a circumferentially continuous wall, a pin 6, an inwardlydirected protuberance 20 in the bore of the shank at or near the free end of the shank so that an end portion of the shank will be deformed outwards when the pin is driven into the shank from the head, and an abutment surface 14 on the head which will engage a panel when the shank of the fastener is inserted through a hole in the panel, the abutment surface being radially spaced away from the shank. In the construction shown the abutment surface is on a rim 16 forming part of the head and both the rim 16 and the shank are circular and the protuberance is in the form of a bead. The pin 6 is initially joined to the remainder of the fastener by a frangible section 8 which is broken when the pin is driven into the shank. When the pin is driven into the shank the head flexes until a stop surface 18 abuts against the panel and after the pin is in a position in which the end portion of the shank is expanded, the resilience of the head urges the shank towards its initial position so that the deformed end portion of the shank forms a tight seal with the edge 22 of the hole in the panel; the abutment surface on the rim 16 also forms a seal with the other side of the panel. The fastener shown serves as a means for attaching a channel-shaped decorative strip with inturned edges to, the panel, the inturned edges being snapped over the heads of a number of the fasteners so as to be anchored in position by the surface 24 of the fasteners. In a modification the shank is formed internally with a second circumferential bead 30 of triangular section and the sharp inner edge of the bead grips the pin 6 tightly and forms a secure seal around the pin. The fastener shown has a tapering end portion to the pin but in a modification the bead 20 is provided with the taper instead of the pin. The stop surface 18 can be omitted if desired. The pin can be provided with a blind bore to increase the resilience of its end portion and instead of the rim being circular it can be elongated with slightly concave sides: The frangible section 8 between the pin and the remainder of the fastener, instead of being continuous as shown, can consist of a few narrow bridges between the pin and the remainder of the fastener; the shank of the fastener instead of being circular in cross-section can be oval, square or triangular and the bead 20 can be replaced by a number of pips. The fastener is made in a mould as shown in Fig. 5 which consists of the two outer parts 51 and 53 and a core pin 50; the preferred materials from which the fastener is made are nylon or an acetal resin and with these materials the shank does not fully return to the as moulded shape after it has been expanded as the core pin is pulled out past the bead 20. To allow for this the exterior of the shank is moulded with a taper.