Mine roof bolt

Claim 1

A mine roof bolt comprising an elongated shaft having threads formed at least on one end thereof; an outer stop member provided at the other end of said shaft and integrally formed with said shaft, said stop member extending laterally outwardly of said shaft; a bolt head having an axially extending passageway provided therethrough, the inner radial dimensions of said passageway being slightly less than the outer radial dimensions of said shaft, said bolt head being force-fitted onto said shaft in abutment with said outer stop member, the force-fit between said bolt head and said shaft being such that said bolt head will disengage from said shaft and rotate with respect to said shaft when a torque of above a pre-determined magnitude is applied to said bolt head; a generally flat washer member having outer radial dimensions greater than those of said bolt head and provided with an axial opening therethrough of generally the same size as said passageway, said washer member being force-fitted onto said shaft with the outer face thereof in abutment with said bolt head; and said outer stop member, said bolt head, and said washer being constructed and arranged with respect to each other such that when a force exceeding a pre-determined magnitude is applied to said bolt head and said washer in the direction of said outer stop member, said bolt head and said washer will move longitudinally of said shaft and said bolt head will creep over said outer stop member until it becomes free of the outer stop member.