Abstract: A casing hammer for simultaneously driving casing and drilling a water well comprises a housing having an annular pneumatic chamber with an annular piston that drives an annular anvil which seals the lower end of the chamber. The chamber is formed by outer and inner sleeves of which the inner sleeve is fixed to an end cap solely at its rear end and is thus cantilevered from the end cap, being free of connection at its forward end. The forward end of the inner sleeve is stabilized by means of a relatively small clearance between the anvil and the sleeves at the front end of the chamber. The cantilevered connection of the inner sleeve at its rear end provides a smooth and unobstructed bore through which extends a rotating drill string that also extends through casing while the casing is being driven by the annular hammer.

Abstract: In accordance with one aspect of the present disclosure, the locking apparatus for maintaining in closed condition the two halves of the casing sections of a high pressure leak-testing apparatus for pipe joints comprises a plurality of bifurcated links. The locking apparatus further comprises a substantial number of hooks having end portions pivotally connected to the bifurcated links, the connections being at relatively thin hook portions which nest with the links. With the described construction by which a bifurcated or yoke-shaped end of one element is nested relative to a relatively thin portion of another element, it is possible to achieve extremely strong locking of the casing sections in closed condition despite the great pressure contained within the tester.In accordance with another aspect of the disclosure, the packer of the leak-testing apparatus comprises a hollow cylindrical mass of rubber which is split, and has insert elements molded therein.

Abstract: A casing hammer for driving casing while drilling a water well comprises a housing having an annular pneumatic chamber with a relatively lightweight, short-stroke annular piston. The piston is reciprocably driven at a high rate to provide a large number of light blows of controllable energy upon an annular anvil that seals one end of the chamber. Percussive blows upon the anvil are transmitted through a drive head and adapter to the upper end of the pipe to be driven. The hammer is suspended from a rotary drive head that operates a hollow drill string extending downwardly through the hammer and through the casing driven thereby.