US 4,467,699 AGranted

Pneumatic motor

AssigneeJoy Manufacturing Company

InventorLouis H. LeBlanc

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Abstract

A valveless, pneumatic motor including a cylinder within which a hammer piston reciprocates and a buffer ring fixedly secured within the cylinder. A source of motive fluid under pressure cooperates with the buffer ring which through supply porting provides pressurized motive fluid alternately to opposed faces of the piston head. Intake ports are formed within the piston stem and adapted to cooperate intermittently with the buffer ring supply porting to provide motive fluid to the piston interior wherein an axial bore transmits the fluid along the stem toward the piston head and discharge porting delivers the motive fluid to the forward face of the piston head thereby urging the piston rearwardly. A reduced diameter portion of the piston stem then comes into communication with the buffer ring supply porting and permits the motive fluid to impinge directly on the rearward face of the piston head without passage through the piston to urge the piston forwardly. Specific porting arrangements and mechanical relationships are disclosed.

A pneumatic motor comprising

a hammer piston having a piston head and a rearwardly projecting piston stem,
a cylinder within which said hammer piston is positioned for relative reciprocating movement,
a buffer ring fixedly secured within a rear portion of said cylinder receiving a portion of said hammer piston stem,
inlet port means in communication with said buffer ring for supplying pressurized motive fluid thereto,
supply port means formed within said buffer ring for delivering said motive fluid to said hammer piston,
intake hammer piston port means in communication with the outer peripheral surface of said hammer piston stem for intermittent communication with said supply port means,
said hammer piston having an axial bore in communication with said intake hammer piston port means,
discharge hammer piston port means in communication with the forward surface of said piston head and said hammer piston axial bore,
a reduced diameter portion of said hammer piston stem disposed between said intake hammer piston port means and said piston head having a diameter less than the internal diameter of said buffer ring,
said buffer ring supply port means when in communication with said intake hammer piston port means adapted to supply motive fluid to the forward surface of said piston head to urge said piston rearwardly and when in communication with said reduced diameter portion of said stem adapted to provide motive fluid to the rearward surface of said piston head by flow externally of said piston to urge said piston forwardly,
said hammer piston having a reduced diameter hammer portion projecting forwardly from said piston head,
said discharge hammer piston port means having a number of passageways diverging from said axial bore to said piston head forward face,
said intake hammer piston port means having a number of passageways oriented generally radially between the periphery of said piston stem and said axial bore,
said piston stem having a generally rearwardly disposed free end, and said axial bore terminating short of the free end of said hammer piston stem, and
reduced diameter bore means connecting said axial bore with the free end of said piston stem.

12 more elements

Abstract

Claims8