Hammer device
AssigneeSandvik AB
InventorRainer Beccu
Life of this patent
Estimating the term…
Abstract
A down-the-hole hammer includes a drill bit and a piston reciprocating therebehind to periodically strike the drill bit. The drill bit includes front and rear portions of difference impedance, and the piston includes front and rear portions of difference impedance. In the drill bit, the front portion has a larger impedance than the rear portion. In the piston, the rear portion has a larger impedance than the front portion.
Claims21
In a hammer device comprising a drill bit disposed at a front end of the device, and a piston mounted longitudinally behind said drill bit for reciprocation in a longitudinal direction to repeatedly strike said drill bit, the improvement wherein:
- said drill bit includes front and rear portions of difference impedance, and said piston includes front and rear portions of different impedance, wherein:
- Z.sub.M1 /Z.sub.T1 is in the range of 3.0-5.5, and
- Z.sub.M2 /Z.sub.T2 is in the range 3.0-5.5,
- where:
- Z.sub.M1 is the impedance of said piston rear portion,
- Z.sub.T1 is the impedance of said piston front portion,
- Z.sub.M2 is the impedance of said drill bit front portion, and
- Z.sub.T2 is the impedance of said drill bit rear portion.
A piston for use in a hammer device for being reciprocated longitudinally into striking engagement with a drill bit located in front of the piston, said piston including front and rear portions of different impedance, wherein:
- Z.sub.M1 /Z.sub.T1 is in the range 3.0-5.5,
- where:
- Z.sub.M1 is the impedance of said piston rear portion, and
- Z.sub.T1 is the impedance of said piston front portion.
A drill bit for use in a hammer device for being repeatedly struck by a longitudinally reciprocating piston located behind said drill bit, said drill bit including front and rear portions of difference impedance, wherein:
- Z.sub.M2 /Z.sub.T2 is in the range 3.0-5.5,
- where:
- Z.sub.M2 is the impedance of said drill bit front portion, and
- Z.sub.T2 is the impedance of said drill bit rear portion.
Dependencies are inferred from the claim text.