Abstract: The present invention is directed to a dynamic seal tube for use in pressurized fluid-driven down hole hammer drills. The dynamic seal tube is a tube that slides within the bore of the piston and the anvil portion of the drill bit and co-operatively acts to release different volumes of pressurized fluid from the lower chamber when the piston is in different predetermined positions.

Abstract: A down-hole hammer includes a two-piece drill bit retained in a casing having an interior surface with a plurality of longitudinal grooves formed therein. The bit shank and the casing are rotationally connected by a number of pins received in the grooves. A symmetrical free piston divides the casing into an upper working chamber and a lower working chamber. The piston slides on an air control assembly including a ported tube extending axially from said air supply to an axial bore in the shank of the bit to guide exhaust air through discharge ports at the cutting face of the bit, the bit reciprocating on the end of the tube. The upper and lower check valves in the air control assembly and openable by supply pressure against a spring bias in response to working fluid supply pressure.

Abstract: A down-hole hammer includes a two-piece drill bit retained in a casing having an interior surface with a plurality of longitudinal grooves formed therein. The bit shank and the casing are rotationally connected by a number of pins received in the grooves. A symmetrical free piston divides the casing into an upper working chamber and a lower working chamber. The piston slides on an air control assembly including a ported tube extending axially from said air supply to an axial bore in the shank of the bit to guide exhaust air through discharge ports at the cutting face of the bit, the bit reciprocating on the end of the tube. The upper and lower check valves in the air control assembly and openable by supply pressure against a spring bias in response to working fluid supply pressure.

Abstract: There is provided a downhole hammer including a drill bit (2) retained by short (4) and long (5) drive pins in the bore of a driver chuck (1). The chuck (1) and bit (2) shank have machined longitudinal grooves (3), every second bit shank groove being blind and connected to the adjacent open groove by a short-pin length relief. The shorter pins (4) are inserted into the visible holes formed by the alignment of the open drill bit grooves and driver chuck grooves (3). The chuck (1) is then indexed which shunts the short pins (4) sideways until the longer pins (5) are insertable. The driver chuck (1) and drill bit (2) are engaged rotationally. The bit (2) slides by the desired distance due to the shorter pins (4) being entrapped in the blind grooves. The arrangement does not require a bit shank extension to accommodate a conventional bit retainer ring.

Abstract: There is provided a downhole hammer including a drill bit (2) retained by short (4) and long (5) drive pins in the bore of a driver chuck (1). The chuck (1) and bit (2) shank have machined longitudinal grooves (3), every second bit shank groove being blind and connected to the adjacent open groove by a short-pin-length relief. The shorter pins (4) are inserted into the visible holes formed by the alignment of the open drill bit grooves and driver chuck grooves (3). The chuck (1) is then indexed which shunts the short pins (4) sideways until the longer pins (5) are insertable. The driver chuck (1) and drill bit (2) are engaged rotationally. The bit (2) slides by the desired distance due to the shorter pins (4) being entrapped in the blind grooves. The arrangement does not require a bit shank extension to accommodate a conventions bit retainer ring.

Abstract: A manually or mechanically/hydraulically operable tong of light weight and high load capacity by means of a multi-layer interlocking construction achieved by cutting the shapes from plate steel by known means, assembling the plate sections in suitable order, and retained with each other by cylindrical steel pins (8) forming a multi hinged tool capable of engaging the job circumference on two or more points equally via replaceable jaw dies (15) retained radially and axially.