Patent GB-1425852-A (GB)
Title: Dowel or anchoring means
IPC: F16B13/10
Filed: 1973-02-05
Abstract: 1425852 Screw sockets; anchoring bolts HILTI AG 5 Feb 1973 [4 Feb 1972] 5608/73 Heading F2H  A wall plug, screw socket, or anchor bolt comprises a two-component adhesive which sets after mixing of the components to secure the plug, socket, or bolt in a bore, at least one of the components being micro-encapsulated with the micro-capsules intimately mixed with the other component, and wedging means to hold the plug, socket, or bolt in the bore while the adhesive sets. In Fig. 1, a bolt 1 having the plain portion 2 of its shank coated with a two-component adhesive 5 is inserted headfirst into a bore 10, and a sleeve 6 having a chamfered leading end 7 is driven over the bolt shank 2 so that the micro-capsules are burst to bring the two adhesive components together. Longitudinal ribs 8 or conical projections on the sleeve outer surface are elastically deformed by the bore wall to wedge the sleeve and the bolt in the bore. In a modification (Fig. 5, not shown), the bolt is replaced by a pin having a frustoconical head (12) at one end and a screwthreaded bore (13) in the other end. The sleeve (6a) is smooth externally and has longitudinal slits (14) extending from its leading end so that when the sleeve is driven over the shank of the pin, the leading end is expanded by the pin head (12) into wedging engagement with the bore wall. In Fig. 6, a wall plug 15 has a tapered bore 16 filled with adhesive. Radial bores 18 are of smaller diameter than the micro-capsules so that when a screw 22 is driven into the plug, the micro-capsules are burst whilst being forced through the bores 18. The screw causes the leading end of the plug 15 to fracture along lines of weakness 19 and expand to grip the base wall, serrations 20 aiding this grip. Fins 21 at the rear of the plug prevent rotation of the plug as the screw is driven into it. If intended for use with a machine screw, the open end of the plug bore has an inward lip to guide the screw thread and to seal the open end against escape of adhesive while the screw is being driven in. In a modification (Fig. 7, not shown) for use with a headless bolt (25), the main bore of the plug is cylindrical, with a tapered part (23) and a small bore cylindrical part (24) at its leading end, which is closed. The bolt (25) is driven in with its threaded portion rearmost, and expands the small cylindrical part (24). In Fig. 8, a pin 26 having a frusto-conical part 27 under its head 28 is first placed in the bore 10. A sleeve 29, having at its rear end a screw socket 32 separate from the main bore 30, is driven over the pin 26 so that adhesive 5 is forced through radial bores 31 and the microcapsules broken. The conical part 27 of the pin expands the leading end of the sleeve against the bore wall. A modification (Fig. 9, not shown) uses a bolt (1b) with a serrated frustoconical head (33), the bolt shank being surrounded by adhesive. A sleeve (35) with a through bore having a divergent portion at its leading end is driven over bolt shank, the microcapsules being burst by passage through radial bores (37) from the divergent portion. The sleeve leading end is expanded by the bolt head (33). A helical spring (38) at the radially outer surface of the adhesive receives the sleeve (38) as it is driven over the bolt shank, and spaces the sleeve from the bore wall. In Fig. 10, the adhesive 5 round a bolt shank 2c is surrounded by a jacket 39 of expanded metal mesh which is deformed by driving in a sleeve 6c to wedge the sleeve in the bore 10. In Fig. 11, an adhesive cartridge 40 of glass, containing a two component adhesive, with one component micro-encapsulated, has a jacket 39a of expanded metal mesh. The cartridge is broken by driving in a fixing rod, the jacket 39a serving as a wedging member. In Fig. 12, not shown, a glass cartridge contains a radially compressed helical spring (41) as well as the adhesive 5. The wall plugs and screw sockets may be of metal or plastics.