Mine roof expansion anchor with improved bore hole engagement means and method of installation thereof

Patent · Tue Jun 15 04:00:00 EDT 1993

OSTI ID:6419890

Wright, R L

An expansion anchor assembly is described for insertion in a bore hole of predetermined diameter in a rock formation to anchor firmly within said bore hole the threaded, upper end of a bolt having a lower end positioned outside said bore hole, said assembly comprising, in combination: (a) an expansion shell having a plurality of leaves generally symmetrical about a central axis and radially expansible into gripping engagement with the wall of said bore hole; (b) a tapered plug having a larger diameter upper end and a smaller diameter lower end and a through, axial bore for threaded engagement with said bolt upper end for axial movement of said plug in response to rotation of odd bolt from a first to a second position to effect radially outward movement of odd leaves, said lower end of said plug being axially spaced from said bolt upper end by first and second distances when said plug is in its first and second positions, respectively; (c) an element axially supporting said shell with respect to said plug and bolt in a position wherein said central axis is substantially with said bolt; (d) means rotationally securing said element to said shell; and (e) resilient bore wall engagement means including a portion of said element extending away from said central axis at a position spaced axially from said upper end of said bolt by a distance at least as great as said second distance, said portion extending radially outwardly from said central axis by a third distance greater than one-half of said predetermined diameter, whereby said portion engages and is deflected inwardly by said bore hole wall and inhibits rotation of said assembly upon insertion of said bolt and anchor into said bore hole and rotation of said bolt.

• Assignee: Eastern Co., Naugatuck, CT (United States)
• Patent Number(s): US 5219248; A
• Application Number: PPN: US 7-883115
• OSTI ID: 6419890
• Country of Publication: United States
• Language: English

Related Subjects

01 COAL, LIGNITE, AND PEAT
012031* -- Coal
Lignite
& Peat-- Underground Mining-- Strata Mechanics & Control-- (1987-)
42 ENGINEERING
422000 -- Engineering-- Mining & Underground Engineering-- (1980-)
BOREHOLES
CAVITIES
DESIGN
EQUIPMENT
EXPANSION
INSTALLATION
MINING
MINING EQUIPMENT
OPERATION
ROOF BOLTS
STRATA CONTROL
UNDERGROUND MINING