Abstract: A coupler device for joining together two segments of a tunnel or shaft lining ring, the device being characterised by a double ended male dowel having an externally grooved cylindrical portion adjacent to both ends. This dowel engages in recesses cast into the segment. A reverse tapered sleeve is cast in the recesses retaining an expandable collar formed of a plurality of arcuate segments, these arctuate segments having complimentary grooves on their inner surface to mate with the grooves on the dowel and a tapered external circumferential portion to abut the reverse tapered sleeve. As the dowel is inserted the arcuate segments, being retained elastically within the reverse tapered sleeve, lock the male part of the device into the recess preventing the device from pulling out.

Abstract: A coupler device for joining together two segments of a tunnel or shaft lining ring, the device being characterised by a double ended male dowel having an externally grooved cylindrical portion adjacent to both ends. This dowel engages in recesses cast into the segment. A reverse tapered sleeve is cast in the recesses retaining an expandable collar formed of a plurality of arcuate segments, these arctuate segments having complimentary grooves on their inner surface to mate with the grooves on the dowel and a tapered external circumferential portion to abut the reverse tapered sleeve. As the dowel is inserted the arcuate segments, being retained elastically within the reverse tapered sleeve, lock the male part of the device into the recess preventing the device from pulling out.

Abstract: A device for joining two members together such as concrete segments for a tunnel lining ring includes a first sleeve for fitting in one of the members to open at a surface thereof and a second sleeve for fitting in the other member. A connecting pin with external ribbing fits in both sleeves, which have internal ribbing, the ribbing of the connecting pin and/or the ribbing of at least one of said sleeves being of resilient material and extending in a substantially parallel direction at an inclined angle to a longitudinal axis of the connecting pin when it is, in use, inserted in the sleeves. The bore of one sleeve is of greater cross-sectional area in one dimension than the bore in the other sleeve, in which other bore the connecting pin can engage as a tight fit, while being able to engage in the firstmentioned bore and traverse it in said one dimension.