Abstract: A backhead assembly system for a Down The Hole (DTH) hammer operated by a supply of compressed fluid, that comprises mainly a backhead, said backhead having a central hole capable of transporting the pressurized air to the hammer and an inner cylinder, coaxially disposed and coupled with releasable holding mediums to the backhead, were said backhead has an interior frontal cavity and said releasable holding mediums are in the mentioned frontal cavity. The hammer also comprises a wear sleeve, coaxially disposed to the backhead and inner cylinder, in which the backhead is coupled to the rear side of the wear sleeve. In both embodiments of the present invention, the inner sleeve has a rear section of less diameter and a front side of larger diameter; both sections joined through a portion of generally increasing diameter.

Abstract: A pressurized fluid flow system for a down the hole drill hammer has a plurality of chambers that exert work, namely one or more auxiliary drive and lifting chambers besides two main chambers located at opposite ends of the piston, the auxiliary chambers each formed around respective waists on the piston and externally delimited by respective cylinders which are arranged longitudinally in series. Two or more internal chambers filled with the pressurized fluid are defined by recesses in the inner surfaces of the piston for supplying said fluid to the work chambers, controlled in a cooperative way by the piston and a control tube coaxially arranged within a central bore of the piston. One or more discharge chambers are formed in between the outer casing and the cylinders for emptying the work chambers through discharge ports in the cylinders. Reverse and normal circulation drill hammers are provided having this system.

Abstract: A pressurized fluid flow system for a reverse circulation down-the-hole hammer includes a cylinder and a cylindrical control tube that are respectively coaxially disposed in between the outer casing and the piston of the hammer and in between the piston and the sample tube. Two chambers help to respectively supply and discharge pressurized fluid into and out of the front and rear chambers that exert work on the piston: an internal chamber, defined by a central recess in the inner surfaces of the piston and permanently connected to the source of pressurized fluid, and a discharge chamber, defined by one or more recesses in the inner surface of the outer casing and permanently communicated with the bottom of the hole. A hammer provided with this system has one or more end discharge ports connected to respective longitudinal discharge channels formed on the outer surface of the outer casing.

Abstract: A pressurized fluid flow system for a down the hole drill hammer has a plurality of chambers that exert work, namely one or more auxiliary drive and lifting chambers besides two main chambers located at opposite ends of the piston, the auxiliary chambers each formed around respective waists on the piston and externally delimited by respective cylinders which are arranged longitudinally in series. Two or more internal chambers filled with the pressurized fluid are defined by recesses in the inner surfaces of the piston for supplying said fluid to the work chambers, controlled in a cooperative way by the piston and a control tube coaxially arranged within a central bore of the piston. One or more discharge chambers are formed in between the outer casing and the cylinders for emptying the work chambers through discharge ports in the cylinders. Reverse and normal circulation drill hammers are provided having this system.

Abstract: A pressurized fluid flow system for a normal circulation down-the-hole hammer comprises a cylinder coaxially disposed in between an outer casing and a piston which reciprocates due to changes in pressure of pressurized fluid contained inside a front chamber and rear chamber located at opposites sides of the piston, supply/discharge of fluid to/from these chambers being conducted through a supply chamber and a discharge chamber defined by recesses on the inner surface of the casing and separated by a dividing wall, the front/rear chambers' in/out fluid flow being controlled solely by the overlap of the piston and the cylinder. A hammer having this system comprises a drill bit with one or more flushing passages which extend from channels cooperatively formed between splines on the inner surface of the driver sub and on the outer surface of the drill bit shank up to the front face of the drill bit.

Abstract: A pressurized fluid flow system for a normal circulation down-the-hole hammer comprises a cylinder coaxially disposed in between an outer casing and a piston that reciprocates due to changes in pressure of the pressurized fluid contained inside of a front chamber and a rear chamber located at opposites sides of the piston, wherein the flow into and out of these chambers is controlled solely by the overlap or relative position of the piston and the cylinder as a supply chamber and a discharge chamber defined by recesses on the inner surface of the outer casing and separated by a dividing wall control the flow of pressurized fluid in and out of the front and rear chambers the.

Abstract: A pressurized fluid flow system for a reverse circulation down-the-hole hammer having a cylinder coaxially disposed in between an outer casing and the piston. This piston reciprocates due to changes in pressure of the pressurized fluid contained inside of a front chamber and a rear chamber at opposite sides of the piston, where the flow into and out of these chambers is controlled solely by the overlap or relative position of the piston and the cylinder as a supply chamber and a discharge chamber, which are defined by recesses on the inner surface of the outer casing and separated by a dividing wall, respectively, supply to and discharge from the front and rear chambers, the pressurized fluid. An internal chamber may also be provided in between the piston and a sampling tube coaxial with the outer casing for a more efficient filling of the chambers.