Expanded – threaded – driven – headed – tool-deformed – or locked-thr – Torque responsive nut or bolt driving connection – Frangible connection
Patent
1985-07-22
1986-06-03
Corbin, David H.
Expanded, threaded, driven, headed, tool-deformed, or locked-thr
Torque responsive nut or bolt driving connection
Frangible connection
405259, 411 40, 411 55, 411 60, F21D 2100, F16B 1306
Patent
active
045926875
ABSTRACT:
An expansion bolt, particularly adapted for supporting the roof of a mine tunnel, includes an elongate stud having distal and proximal threaded ends. Coaxially mounted on the stud near the distal end is an expansion sleeve that is axially divided into a plurality of circumferentially-spaced sleeve segments. A cam element is threadedly attached to the distal stud end. The cam element is formed of a sheet metal stamping; and includes an annular collar with a plurality of circumferentially-spaced fingers extending proximally from the periphery of the collar. The fingers also taper radially outwardly to give the cam element a frusto-conical configuration. The proximal ends of the fingers engage the interior surface of the sleeve near the distal end of the sleeve. The sleeve is constrained from axial movement on the stud, and the stud is rotatable independently of the cam element and the sleeve. The proximal end of the sleeve has a nut adapted for the application of a torque thereto. The nut is attached to the stud by a shear pin that allows the nut and the stud to turn together until a predetermined torque level is reached. Rotation of the stud flattens the cam element axially, causing its fingers to spread radially outwardly against the sleeve segments, camming the latter in a radially outward direction. When the predetermined torque is applied, the nut is advanced axially on the stud toward the distal end, bringing the nut into engagement with a pressure plate carried on the stud between the nut and the sleeve.
REFERENCES:
patent: 2159580 (1939-05-01), Zifferer
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patent: 2218581 (1940-10-01), Levan
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patent: 3191486 (1965-06-01), Gibbens
patent: 3211044 (1965-10-01), White
patent: 3267792 (1966-08-01), Yackle
patent: 3315557 (1967-04-01), Dickow
patent: 4173918 (1979-11-01), Piersall
patent: 4483645 (1984-11-01), White et al.
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