Abstract: A retainer device (10) is provided for retaining a drill bit (12) within a percussive drill assembly casing (2). The retainer device (10) includes a generally annular body (16) having a central axis and an inner circumferential shoulder portion (18) disposable within the casing (2) such that the body axis (17) is substantially collinear with a casing axis (2a). The shoulder (17) is deflectable between a first position (P1), where the shoulder (18) is contactable with the bit head (14) to retain the bit (12) within the retainer body (16), and a second position (P2). The second position (P2) is spaced radially outwardly from the first position such that the bit head (14) is displaceable through the body (16) in a direction along the casing axis (2a). Also, the retainer device (10) includes a spacer (24) that locates the retainer body (16) at a desired axial position within the casing (2) and a centralizer (26) that centers the body (16) about the casing axis (2a).

Abstract: A fluid channeling device is for a percussive drill including a casing having an interior space, drive and valve chambers defined within the interior space, a piston disposed within the casing and having an upper end disposeable within the drive chamber and a longitudinal through-bore, and a valve for controlling flow into the drive chamber. The device includes a first member partially disposed within the drive chamber so as to extend into the piston bore when the piston end is within the drive chamber. The first member has an outer surface, an interior space and one or more ports extending between the outer surface and interior space and fluidly connectable with the drive chamber. A second member is disposed within the first member interior and has a passage fluidly connected with the valve chamber and fluidly connectable with the port(s) to establish fluid communication between the drive and valve chambers.

Abstract: A portable screw fastener driving tool is driven electrically from a solid state inverter and intended to be coupled to any selected one in a set of screw fastener engaging members, each demanding a drive enabling tightening of the engaged fastener by parameters (e.g. torque, angle, speed) specific to its size or type. Code elements are provided on the members in a binary code pattern specific for each member. Sensors on the tool read the code pattern on the member connected to the tool and serve it electrically to a decoding unit which transforms the read binary pattern to signals adapted to control the inverter the way the member demands.

Abstract: A bolt for transmitting axial load having a head provided with a weakening slot for promoting elastic deformation of the head in response to the axial load magnitude. On the head there is a pair of measure points located at each side of the slot in or adjacent the free end surface of the head at a distance between them that decreases at increasing axial load on the bolt. The bolt head also comprises a pair of reference points located either in the same axial plane as the measure points but in a direction perpendicular to the latters or in a plane axially spaced from that of the measure points adjacent the bottom of the weakening slot. The location of the reference points is such that the relative distance between them remains unaffected by the deformation of the bolt head and thereby the axial load transmitted by the bolt.

Abstract: In rock drilling, the dust-laden flushing air from the borehole is drawn through a coarse dust separator and a filter unit. A mixing apparatus is screwed to the bottom of the filter unit and in accordance with this invention the dust that falls from the filter unit is fed in batches to a mixing chamber of the mixing apparatus in which it is mixed with a liquid binder. The dust from the coarse dust separator is directly dumped on the ground and the fine dust from the mixing apparatus is also dumped on the ground.

Abstract: A method for binding dust generated when rock drilling, by mixing said dust with a liquid. The apparatus to perform the method includes a mixing chamber (6) connected to a dust-separating means (1, 3); means for passing gravitationally to the mixing chamber (6) batches of dust collected in the separating means; and means (12) for supplying a liquid binder to the mixing chamber in an amount corresponding to the size of the batch of dust in question. Arranged in the mixing chamber (6) are means (7, 8) for mixing the dust and liquid by agitation while the next batch of dust is being collected in the separating means (1). The resultant mixture is discharged prior to the next batch of dust being supplied to the mixing chamber.

Abstract: A hard compact material, such as rock, is broken by forcing an elongated mass body of relatively incompressible fluid, such as water, against the material to be broken. The mass body is caused to impact the material at a momentum necessary for breaking the material. The momentum is generated by supplying the fluid to a storage chamber against the effect of a thrust load acting upon the fluid in the storage chamber. When a sufficient amount of fluid has been supplied the fluid in the storage chamber is forced toward the material to be broken by the effect of the thrust load.

Abstract: A drill wagon has oscillatable crawler frames. Each crawler frame has a hydraulic ground engaging support jack at one end.

Abstract: The various air motors of a rock drilling rig are supplied with oil through oil lines which are furnished with predetermined metered oil flows from positive displacement pumps that are operated in synchronism with each other by an air operated oscillator. There is a normally closed shut-off valve in each oil line. The respective shut-off valve is opened when the respective air line is pressurized. When a shut-off valve is closed, the respective metered oil flow escapes through a pressure relief valve.

Abstract: The various air motors of a rock drilling rig are supplied with oil through oil lines which are furnished with predetermined metered oil flows from positive displacement pumps that are operated in synchronism with each other by an air operated oscillator. There is a normally closed shut-off valve in each oil line. The respective shut-off valve is opened when the respective air line is pressurized. When a shut-off valve is closed, the respective metered oil flow escapes through a pressure relief valve.