Patent ID: 8561730
Filing Date: 2013-10-22
Classification: B21K,E21B

Abstract:
1. A foot valve assembly for a down-the-hole (“DTH”) drill that includes a drill bit including a bit bore having a bit bore diameter, the assembly comprising: a cylindrical member having a cylindrical member outer diameter larger than the bit bore diameter and including a cylindrical member bore defining a cylindrical member inner diameter, the cylindrical member having a cylindrical member rigidity; and a support sleeve having an outer sleeve diameter less than the cylindrical member inner diameter and inserted into the cylindrical member bore to form a cylindrical member and sleeve assembly, at least a portion of the support sleeve having a rigidity greater than the cylindrical member rigidity; wherein the cylindrical member and sleeve assembly is inserted into the bit bore, which causes the cylindrical member to deform such that the outer diameter of the cylindrical member can fit within the bit bore and such that the cylindrical member deforms against the support sleeve to fit within the bit bore, such that the cylindrical member is fixedly sandwiched between the support sleeve and the bit bore; and wherein the cylindrical member and support sleeve assembly includes a gap between the support sleeve and the cylindrical member bore prior to insertion of the cylindrical member and support sleeve assembly into the bit bore; and wherein deformation of the cylindrical member during insertion into the bit bore closes the gap and causes the cylindrical member to apply pressure to the support sleeve.