Abstract:
An annular air-hammer apparatus for drilling holes incorporates a hollow cylindrical case with a stepped bore which has inlet and outlet ports. A rock-cutting tool with an axial opening is fitted to the case at the forward end thereof. A chips-receiving sleeve and a stepped ring-shaped hammer are located inside the case, whereby the hammer forms a working-stroke chamber with the case and an idle-stroke chamber with the case, the rock-cutting tool and the chips-receiving sleeve. The chips-receiving sleeve has a cylindrical protuberance at its upper end which interacts with the hammer when this is in its topmost position. A channel is provided in the idle-stroke chamber at that side thereof which faces the upper end face of the hammer.
Abstract:
A FLUID ACTUATED ROCK DRILL OF THE PERCUSSIVE TYPE IS PROVIDED WITH AN OVERRIDING CLUTCH ADAPTED TO BE ACTUATED BY THE OPERATING FLUID IN TIMED RELATION WITH THE PERCUSSIVE MECHANISM TO ROTATE THE DRILL STEEL.
Abstract:
The invention relates to a probe assembly (1) adapted to penetrate and travel in a mass of material, comprising:a hull,a front striking zone (3) and/or a rear striking zone (4) axially opposite, for transmitting pulses to the hull,a striking piston (2) anda pneumatic motor for setting in motion the striking piston (2) so as to project it against a striking zone (3, 4) integral with the hull, a compressed-air supply for the motor, characterized by the fact that the friction of the hull and any guiding elements rigidly connected to the hull in a pulverulent mass is between a lower value f insufficient to assure the holding of the probe upon the recoil of the striking piston (2) and a higher value F preventing the probe from advancing upon the impact of the striking piston (2) on the striking zone (3, 4) so as to permit the advancement of the probe in the pulverulent material.
Abstract:
A rock drill is provided including a flap valve allowing high cutting speed operation over a range of compressed air pressures. The rock drill further includes a wear sleeve secured to a back head with a chuck to the opposite side, an inner cylinder within the wear sleeve, a valve seat at the inner end of the cylinder with a valve stem extending into the cylinder, and a piston within the cylinder reciprocable from one position where the valve stem engages a bore in the piston to a position where the stem enters a bearing in the cylinder to strike a drill bit held by the chuck. The ratio of the piston head area to its bore area is 9.9/9.95 to 1. The ratio of the piston head length to the stem length is 1.5/1.52 to 1. The ratio of piston head diameter to stem diameter is 1.4/1.43 to 1 and the ratio of piston stem length to the length of stem within the bearing at the point at which the piston strikes the bit is 1.4/1.45 to 1.
Abstract:
A hammer and more particularly a fluid operable hammer wherein alternating impetus provided by pressurized liquid and gas means actuates a reciprocable hammer piston to generate repetitive impact loads. A work member is provided to receive blows from the hammer and includes an enlarged portion located in a sealed, variable volume cushion chamber. Means are provided to provide fluid above atmospheric pressure in the chamber. The chamber is sealed before hammer operation to provide a variable gas pressure cushioning chamber for the work member.
Abstract:
A tool for cutting percussive rotary drilling of boreholes includes a hollow casing having a bit. A hammer piston is installed in the casing for reciprocations and for cooperation with the bit for imparting impact impulses thereto. The hammer piston divides a working space of the casing into a workstroke chamber and a return stroke chamber which are alternately connected through distribution means provided in the casing with a source of a fluid under pressure for reciprocations of the hammer piston. There are provided controlled throttling means in permanent communication with distribution means which can be set to two limit positions, so that in the first position they provide for a partial supply of a fluid for reciprocations of the hammer piston with minimum kinetic energy and in the second position the throttling means are completely closed so as to provide for the full supply of a fluid to the workstroke and return stroke chambers through the distribution means for reciprocations of the hammer piston at maximum kinetic energy. There are provided control means which are coupled to the bit and to the controlled throttling means for setting them to the first position when the bit encounters a soft rock and to the second position when the bit encounters a hard rock.
Abstract:
A fluid operated reciprocating piston rock drill wherein the piston has a stem portion closely slidably received in a guide bushing and the cylinder of the rock drill provides clearance space around the head of the piston.