# US 4,400,122 A · Expansion bolt

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- Number: US 4,400,122 A
- Document ID: US4400122A
- Status: Granted
- Kind: A
- Application number: 06/226,280
- Filed: 1981-01-19
- Granted: 1983-08-23
- Earliest claimed: 1981-01-19
- Assignees: Coalequip (Proprietary) Limited
- Inventors: Daniel Minnaar; Clive Straughan
- Web page: https://patentgrep.com/patent/US4400122A

## CPC

- F16B 13/066: {fastened by extracting a separate expander-part, actuated by the screw, nail or the like}
- E21D 21/008: {Anchoring or tensioning means}
- F16B: DEVICES FOR FASTENING OR SECURING CONSTRUCTIONAL ELEMENTS OR MACHINE PARTS TOGETHER, e.g. NAILS, BOLTS, CIRCLIPS, CLAMPS, CLIPS OR WEDGES; JOINTS OR JOINTING (couplings for transmitting rotation F16D)
- E21D: SHAFTS; TUNNELS; GALLERIES; LARGE UNDERGROUND CHAMBERS (soil-conditioning or soil-stabilising materials C09K17/00; drilling or cutting machines for mining or quarrying E21C; safety devices, transport, rescue, ventilation or drainage E21F)

## Abstract

The invention relates to an expansion bolt of a type having an expansible shell arranged on an elongated stud, with a tapered plug being provided to expand the shell in use. In order to render the bolt more versatile, a spacer is provided between the plug and the expansible shell, the spacer being in the form of finger elements which engage the inner surface of the shell to expand it.

## Claims

### Claim 1

An expansion bolt comprising an elongated stud member which is adapted to provide an anchorage at its leading end in use, a plug element secured to the stud towards its remote trailing end, an expansible shell on the stud, a spacer member disposed on the stud intermediate the shell and the plug, the spacer member being comprised of a plurality of elongated finger elements which are adapted to expand the shell radially upon movement of the plug towards the shell and deformable means coupling the ends of the finger elements adjacent the plug element together, said deformable means having sufficient strength to ensure the expansion of said shell prior to the radial expansion of said finger elements of said spacer.

### Claim 2 (depends on 1)

The expansion bolt according to claim 1 wherein the expansible shell comprises two or more longitudinal leaf elements.

### Claim 3 (depends on 2)

The expansion bolt according to claim 2 wherein the spacer is adapted to engage the inner surfaces of at least some of said leaves of the shell to expand such leaves radially.

### Claim 4 (depends on 1)

The expansion bolt according to claim 1 wherein the remote ends of the finger elements are deformably coupled together by means of a uniting claw forming the remote extremity of the bolt.

### Claim 5 (depends on 1)

The expansion bolt according to claim 1 wherein the finger elements are releasably bound to the stud by means of an encircling spring clip.

### Claim 6 (depends on 3)

The expansion bolt according to claim 3 wherein the inner surfaces of the leaves of the shell and the outer surfaces of the spacer fingers, which mate in use, are substantially parallel.

### Claim 7 (depends on 1)

The expansion bolt according to claim 1 wherein the inner surface of the fingers of the spacer and the outer surface of the plug are substantially parrallel.