Jennmar Corporation

Glen S Grissinger

John C Stankus

Eugene H Stewart

Jerry E Frease

A roof anchor for supporting an underground mine roof or the like is provided. The roof anchor has an elongated shaft with a head formed at one end. The head supports a washer and a roof supporting plate that surrounds the mouth of a blind bore formed upwardly into the roof. A resin capsule is positioned within the blind bore above the roof anchor. The shaft of the roof anchor has an adjustably securable annular washer surrounding the shaft. The annular washer is fixed in a position so that when the resin capsule is ruptured to release the resin to bind the roof anchor within the bore hole, the resin completely fills the bore hole from the blind end of the bore to the rigid annular washer fixed to the shaft of the roof anchor. By making the position of the annular washer axially adjustable, the roof anchor may be utilized with varying amounts of resin as conditions at the mine site require and still cause the resin to be subjected to a compressive force within the bore hole in the space between the end of the bore hole and the annular washer.

Mine roof anchor having adjustable resin retaining washer

The mine roof anchor includes a roof bolt assembly with an expansion shell assembly secured at the end of the bolt inserted into the bore hole. The expansion shell assembly includes a friction reducing means to increase the horizontal force on the leaves and the bolt assembly includes an adjustable resin retaining washer to compress the resin in the bore hole.

Mine roof anchor having adjustable resin retaining washer and expansion

A roof anchor for supporting an underground mine roof or the like is provided. The roof anchor has an elongated shaft with a head formed at one end. The head supports a washer and a roof supporting plate that surrounds the mouth of a blind bore formed upwardly into the roof. A resin capsule is positioned within the blind bore above the roof anchor. The shaft of the roof anchor has an adjustably securable annular washer surrounding the shaft. The annular washer is fixed in a position so that when the resin capsule is ruptured to release the resin to blind the roof anchor within the bore hole, the resin completely fills the bore hole from the blind end of the bore to the rigid annular washer fixed to the shaft of the roof anchor. By making the position of the annular washer axially adjustable, the roof anchor may be utilized with varying amounts of resin as conditions at the mine site require and still cause the resin to be subjected to a compressive force within the bore hole in the space between the end of the bore hole and the annular washer.

Growing community of inventors

Hollidaysburg, PA, United States of America

Glen S Grissinger