Roof bolt with expansion shell and threaded nut

Patent · Tue Jul 07 00:00:00 EDT 1987

OSTI ID:6152959

Calandra, F Jr

Apparatus is described for supporting a rock formation comprising, an elongated rod positioned in a bore hole of a rock formation. The rod has a first threaded end portion and a second threaded end portion. The first threaded end portion is positioned adjacent the end of the bore hole, the rod second threaded end portion extending out of the bore hole. An expansion shell assembly engaged to the rod first threaded end portion. A bearing plate is positioned on the rod second threaded end portion. A nut engages the rod second threaded end portion below the bearing plate. Stop means obstructs axial movement of the nut beyond a first position on the rod second threaded end portion to permit the initial rotation in the preselected direction of the nut and the rod as a unit. The expansion shell assembly is operable upon rotation of the rod in the bore hole to anchor the rod in a fixed position in the bore hole. The stop means is operable to permit axial movement of the nut on the rod second threaded end portion when a predetermined torque is exceeded during the continued rotation of the nut and the rod in the preselected direction. The nut is rotatable relative to the rod and operable to advance during further rotation of the nut in the preselected direction to a second position on the rod second threaded end portion to urge the bearing plate against the rock formation and tension the rod.

• Assignee: Jennmar Corp., Pittsburgh, PA
• Patent Number(s): US 4678374
• OSTI ID: 6152959
• Country of Publication: United States
• Language: English

Related Subjects

01 COAL, LIGNITE, AND PEAT
012031* -- Coal
Lignite
& Peat-- Underground Mining-- Strata Mechanics & Control-- (1987-)
BOREHOLES
CAVITIES
COAL MINES
DESIGN
EQUIPMENT
EXPANSION
FASTENERS
JOINTS
MINES
MINING
MINING EQUIPMENT
OPERATION
POSITIONING
ROOF BOLTS
SHELLS
THREADED JOINTS
TORQUE
UNDERGROUND FACILITIES
UNDERGROUND MINING