Rotary drill bits
AssigneeDrilling & Service U.K. Limited
InventorJohn D. Barr
Life of this patent
Estimating the term…
Abstract
In a rotary drilling bit having preform cutting elements, a partial or total structural discontinuity is disposed between the elements and the underlying structure or within the underlying structure to reduce the bending strain upon the preform cutting elements. In this way there is a reduction in the fracture or damage of preform cutting elements.
Claims17
A rotary drill bit for deep hole drilling or coring in subsurface formations comprising a body with a shank having a fluid bore, said body carrying a plurality of preform cutting elements and support members, in which each preform cutting element is loosely mounted in contact with the respective support member and flexible locating means are provided to hold the preform cutting element in contact with the support member and to reduce the bending strain in the preform cutting element caused by deflection of the support member in use of the bit, in which the flexible locating means comprises an elongate locating means one end of which is fixed to the bit body at a position spaced from the support member and the other end of which urges the preform towards the support member.
A rotary drill bit for deep hole drilling or coring in subsurface formations comprising a body with a shank having a fluid bore, said body carrying a plurality of preform cutting elements and support members in which each preform cutting element is loosely mounted in contact with the respective support member and flexible locating means are provided to hold the preform cutting element in contact with the support member and to reduce the bending strain in the preform cutting element caused by deflection of the support member in use of the bit, in which the preform cutting element is bonded to a backing element which is loosely mounted in contact with the support member and the flexible locating means is arranged to hold the backing element in contact with the support member.
A rotary drill bit for deep hole drilling or coring in subsurface formations comprising a body with a shank having a fluid bore, said body carrying a plurality of preform cutting elements and support members, in which each preform cutting element is loosely mounted in contact with the respective support member, and in which at least one slot or aperture is provided extending parallel to the major face of the preform to reduce the bending strain in the cutting element caused by deflection of the support member in use of the bit.
Dependencies are inferred from the claim text.