Abstract: A shock absorber for use with a borehole drill string and which is to take a rotational load and absorb axial shock loading, the absorber consisting essentially of a pair of oppositely disposed components adapted for connection into a drill string and positioned on opposite sides of a resilient member, the latter being held between rigid rings around and separate from the components, each ring being secured to the component on the opposite side of the member.

Abstract: The invention is concerned with pneumatic percussion drilling equipment with advantageous manufacturing simplicity and effective piston area to casing size consisting essentially of an elongate hollow casing housing a piston assembly and having a backhead at one end with a compressed fluid inlet, a bit assembly with a compressed fluid exhaust at the other end, and the backhead including a seal for a backhead end of the piston reciprocatable within the casing, the piston having axial bores extending inwardly from each end, inclined passages extending away from the inner ends of the axial bores to open through the wall of the piston at positions axially displaced from each other and towards opposite ends of the piston from their respective axial bores, and the casing walls having axially spaced apart recesses, the backhead seal, casing recesses and opening through the wall of the piston being such as to allow fluid under pressure introduced axially into the casing through the backhead, to reciprocate and to mai

Abstract: The invention relates to an extraction device used for extracting pneumatically actuated impact tools and the like from boreholes. The device includes a carrier member 1, a reciprocable hammer 2, and a sleeve, 13. The carrier is adapted to be connected to a drill rod secton. Reciprocation of the hammer relative to the carrier may be used to effect extraction. Fluid passages are provided for conveying fluid under pressure through the device in order to cause the hammer to reciprocate.

Abstract: A valveless pneumatic hammer comprising a backhead assembly at one end of a hollow casing and a bit assembly at the other end of the casing, a rod extending into the casing and having a passage out to atmosphere at the other end of the assembly, a chamber divider in the backhead end of the casing having a control rod projecting into the casing, a piston having a large bore in one end and a smaller bore end and the larger bore end being adapted to cooperate with the chamber divider end for the sealing of the larger bore, the piston reciprocating between a first position with the smaller bore end against the bit assembly, and a second position with the piston displaced towards the backhead assembly, a first chamber with the piston in the first position, a second chamber with the piston in the second position, first and second fluid supply paths through the backhead assembly, between chamber divider walls and the casing wall, first and second fluid exhaust paths from the first and second chambers, respectively o

Abstract: A drilling machine comprises a rotary motor mounted to an assemblage of rigid bar linkages. Means are provided for moving the linkages relative to each other. The linkages are connected together in a configuration which ensures that as the linkages move relative to each other the rotary motor moves along a vertical line. Preferably the machine will be mounted on a suitable vehicle. The invention extends to a method of drilling.

Abstract: A pneumatic percussion machine has chambers at its ends with air inlet and exhaust passages thereto, controlled by a piston reciprocable between the chambers, an air supply passage from an axially adjacent end chamber to a third chamber being opened only after the air supply to the other end chamber is closed off.

Abstract: A valveless pneumatic hammer comprises a hollow casing having a backhead assembly at one end and a bit assembly at the other, and a piston reciprocable in the casing. There is a chamber divider at the backhead end of the casing which co-operates with the piston for conducting fluid under pressure into alternate chambers, one at each piston end, for reciprocation of the piston. A chamber divider is located within the casing by a locating split ring which holds the chamber divider axially against the backhead assembly. The chamber divider also has a recess in the end thereof nearest the piston which together with a bore in this piston end, comprises the fluid chamber at this end of the casing.