Drilling machine with driving tool for casing or pipe

Claim 1

A drilling machine having a tower with drill power means movable lengthwise of said tower and carrying drill pipe sections, said drilling machine carrying a driving tool for casing sections, said driving tool having a hammer barrel with an interior bore vented to atmosphere, said bore having a smaller diameter portion at one end communicating with a larger diameter portion at the other end, the area between said small and large diameter bore portions providing a generally transversely extending anvil surface, a plate having an open central portion closing said large diameter bore portion, a spindle element extending from said plate coaxially through said bore and terminating adjacent the end of said small diameter bore portion, a piston element movable within said bore coaxially around said spindle element, said piston element having a small diameter portion slidably received within said small diameter bore portion and a large diameter portion slidably received within said large diameter bore portion, the large diameter bore portion being adapted for connection to a constant source of pneumatic pressure, the small diameter portion of the bore being adapted for connection to an intermittent source of hydraulic pressure, said plate carrying thereon a chucking mechanism coaxially of said spindle element and having a series of jaws for engaging a drill pipe section passing through said spindle element.