Nonrotary piston for jackhammer and removable splined nut therefor
AssigneeIngersoll-Rand Company
InventorsPaul B. Campbell, Robert R. Kimberlin, Sean M. O'Malley, Roland P. Holt
Life of this patent
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Abstract
A fluid-activated, percussive impact tool has a piston therein that reciprocates longitudinally but not rotationally. The piston activates a wrap spring clutch to rotate the drill steel. A removable splined nut in combination with the tool's housing restrains rotation of the piston, while permitting longitudinal reciprocation of the piston.
Claims4
A removable, splined nut for restraining from rotation a reciprocal piston in a housing of a fluid-activated percussive impact tool, said piston having a piston stem with a plurality of longitudinal grooves thereon comprising:
- a nut body having an axis, a top end, a bottom end and a center portion therebetween;
- an internal surface on said body having at least one longitudinally extending spline thereon, for slidably connecting to a longitudinal groove in said piston stem;
- and
- an external surface forming a circumference with at least one male profile lobe thereon, said at least one male profile lobe being formed by a rounded projection extending radially outwardly from said circumference, wherein said external surface is tapered such that, when viewed in a direction perpendicular to the axis of said nut body, said at least one male profile lobe has a center apex portion between said top and bottom ends for interference fit into a housing portion having at least one female profile lobe cavity adapted to receive said at least one male profile lobe.
In a fluid-activated jackhammer having a backhead at a top end, a drill steel chuck at a bottom end, a housing extending therebetween forming a central bore having a reciprocal piston supported therein for reciprocation along a longitudinal axis, and a wrap spring clutch for causing rotation, in one direction, of a drill steel in said chuck during reciprocation of said piston, the improvement comprising:
- said piston having a piston stem, a piston tail and a piston head therebetween;
- a plurality of longitudinal grooves extending downwardly along said piston stem and spaced apart around a circumference of said piston stem;
- and
- a removable nut body having an axis, a splined internal surface slidably connected to said longitudinal grooves, and a male profile lobed external surface restrained in said housing, said external surface forming a circumference with at least one male profile lobe thereon, said at least one male profile lobe being formed by a rounded projection extending radially outwardly from said circumference, wherein said external surface is tapered such that, when viewed in a direction perpendicular to the axis of said nut body, said at least one male profile lobe has a center apex portion between said top and bottom ends for interference fit into a housing portion having at least one female profile lobe cavity, whereby rotation of said nut body and said piston is restrained but longitudinal movement of said piston is permitted.
Dependencies are inferred from the claim text.