Reversible bit bearing
AssigneeIngersoll-Rand Company
InventorWarren T. Lay
Life of this patent
Estimating the term…
Abstract
A fluid-activated, percussive, down-the-hole drill having a reversible bearing and bit combination for altering the volume of return reservoir exhaust fluid between a larger amount for deep hole drilling and a smaller amount for shallow hole drilling.
Claims11
In a fluid-activated, percussive, down-the-hole drill, having a hollow cylindrical drill casing;
- a chuck connected to a bottom end of the drill casing;
- a drill bit connected to the chuck;
- a back head assembly fluidly connecting the drill to a drill string;
- a piston slidably mounted within the drill casing for reciprocating between an impact position in contact with the drill bit and a return position not in contact with the drill bit;
- drive chamber fluid passageway means for providing a first reservoir of percussive fluid for reciprocating the piston between the return position and the impact position;
- return chamber fluid passageway means for providing a second reservoir of percussive fluid when the piston is in the return position, for exhausting from the drill;
- and exhaust fluid passageway means for conducting the percussive fluid from the return chamber fluid passageway means through the drill to an exhaust port, to lift debris up a drillhole, the improvement comprising:
- (a) reversible bearing means between the drill casing and the drill bit, for varying the volume of said return chamber reservoir between a larger preselected amount, for deep drilling, and a smaller preselected amount, for shallow drilling.
A reversible bearing for removable insertion in a fluid-activated, percussive, down-the-hole drill, having a hollow cylindrical drill casing;
- a chuck connected to a bottom end of the drill casing;
- a drill bit connected to the chuck;
- a back head assembly fluidly connecting the drill to a drill string;
- a piston slidably mounted within the drill casing for reciprocating between an impact position in contact with the drill bit and a return position not in contact with the drill bit, said bearing comprising:
- (a) a hollow cylinder for concentric mounting around the drill bit;
- (b) said bearing having an internal surface adapted to be spaced from the drill bit, with a land portion protruding inwardly toward the drill bit;
- (b) said land portion adapted to be spaced from said drill bit when said bearing is mounted in said first position;
- and
- (c) said land portion adapted to be in sealing contact with said drill bit, when said bearing is mounted in said second, reverse position.
In a fluid-activated, percussive, down-the-hole drill, having a hollow cylindrical drill casing;
- a chuck connected to a bottom end of the drill casing;
- a drill bit connected to the chuck;
- a back head assembly fluidly connecting the drill to a drill string;
- a piston slidably mounted within the drill casing for reciprocating between an impact position in contact with the drill bit and a return position not in contact with the drill bit;
- drive chamber fluid passageway means for providing a first reservoir of percussive fluid for reciprocating the piston between the return position and the impact position;
- return chamber fluid passageway means for providing a second reservoir of percussive fluid when the piston is in the return position, for exhausting from the drill;
- and exhaust fluid passageway means for conducting the percussive fluid from the return chamber fluid passageway means through the drill to an exhaust port, to lift debris up a drillhole, the improvement comprising:
- (a) reversible sealing means between the drill casing and the drill bit, for varying the volume of said return chamber reservoir between a larger preselected amount, for deep drilling, and a smaller preselected amount, for shallow drilling;
- (b) said reversible sealing means comprising:
- (i) an external land surface on the piston in sealing contact with the drill casing;
- (ii) an external surface on the drill bit having a land portion protruding toward the drill casing;
- (iii) a reversible bearing removably inserted in the drill casing;
- (c) said bearing further comprising:
- (i) a hollow cylinder concentrically spaced around the drill bit;
- (ii) said bearing having an internal surface spaced from the drill bit and a land portion protruding inwardly toward the drill bit;
- (iii) said bearing land portion, being spaced from said drill bit when said bearing is mounted in said first position;
- and
- (iv) said bearing land portion being in sealing contact with said drill bit land portion, when said bearing is mounted in said second, reverse position,
- (d) whereby, said bearing, in combination with the drill casing, chuck, drill bit, and piston provides:
- (i) in a first bearing position, a first preselected reservoir of percussive fluid in said return chamber, for deep drilling;
- and,
- (ii) in a second, reverse bearing position, a second preselected reservoir of percussive fluid in said return chamber, for shallow drilling, said second reservoir of percussive fluid being smaller than said first reservoir of percussive fluid.
A bearing for reversible use in a down-the-hole-drill, comprising:
- a) a hollow cylinder having an internal surface, and external surface, a top end and a bottom end;
- b) an inwardly protruding circumferential sealing land portion on the internal surface between the top and bottom ends, said inwardly protruding sealing land being a first distance from the top end and a second distance from the bottom end, said first and second distances being different, whereby when the bearing is used in a first position in the drill, the sealing land is in a sealing position with respect to;
- a portion of the drill, and when the bearing is used in a second position in the drill, which is the reverse of the first position, the sealing land is out of the sealing position;
- c) a first undercut portion on the external surface adjacent the top end;
- d) a second undercut portion on the external surface adjacent the bottom end;
- and
- e) at least one circumferentially extending land portion on the external surface.
Dependencies are inferred from the claim text.