Abstract The piston of a pneumatic cylinder is reciprocated with a controllable dwell time at each end of its stroke, under the control of a digital fluidic circuit which responds to the termination of exhaust flow at the end of each piston stroke to initiate the reverse piston stroke. The air for driving the piston is supplied alternately to opposite ends of the piston through respective cylinder ports, by way of a corresponding pair of pilot valves which are controlled by the fluidic circuit so that one or the other of the pilot valves may supply driving air to the piston at any time. Whenever the piston is in motion, a stream of exhaust air flows through the exhaust port ahead of the piston, and this exhaust stream acts through the fluidic control circuit to maintain the pilot valves in their then-existing states; when the exhaust stream stops at the end of a piston stroke, the fluidic circuit responds to produce a pneumatic pulse delayed by a controllable time with respect to termination of exhaust flow, and this delayed pulse triggers a two-state fluidic device to its opposite state; this in turn reverses the states of the pilot valves so that the other pilot valve now supplies driving air to the opposite end of the piston to drive it in the opposite direction. Reciprocation can be "turned off" by supplying a simulated exhaust stream to the fluidic circuit. Fluidic outputs indicative of the direction of piston movement and of whether reciprocation is occurring are also provided.
Inventors
👤 Frederick W. Martin
Bibliographic Details
Application Number—
JurisdictionUS
Data Sourcegoogle_patents
Last Synchronized2026-11-01 03:51
CPC Classifications
F; F01; F01L; F01L29/00
Claims Analysis
Total Claims: 4
Claim 1
Independent Claim
300 words
Apparatus for controlling the reciprocation of a piston in a cylinder chamber having a first port near one end thereof and a second port near the other end thereof, each said port being positioned beyond the cylinder wall portion sealed off by said piston when in its most extreme positions, said apparatus comprising: first and second pilot valve means each having a cylinder connection, an exhaust connection, a cylinder-air supply connection, and a pilot control connection responsive to a change in fluidic pressure to switch said cylinder connection from communication with said cylinder-air connection to communication with said exhaust connection; means connecting said cylinder connections of said first and second pilot valve means to said first and second ports respectively; a source of cylinder-air connected to said cylinder-air supply connections of both of said first and second pilot valve means; first fluidic means responsive to simultaneous occurrence of substantially zero exhaust flow from said exhaust connections of said first and second pilot valve means to switch its output from a first position to a second position; second fluidic means having two output connections and two stable output states in one of which states the fluidic pressure at one of said two connections is high compared to that at the other of said two output connections and vice versa in the other of said two states; means responsive to each occurrence of said second output position of said first fluidic means to reverse the state of said second two-state fluidic means; and means connecting said output connections of said second two-state fluidic means to respective pilot control connections of said first and second pilot valve means to switch said first and second pilot valve means alternately at times determined by the times of said simultaneous occurrences of substantially zero exhaust flow.
Claim 2
Dependent Claim
300 words
Apparatus for controlling the reciprocation of a piston in a cylinder chamber having a first port near one end thereof and a second port near the other end thereof, each said port being positioned beyond the cylinder wall portion sealed off by said piston when in its most extreme positions, said apparatus comprising: first and second pilot valve means each having a cylinder connection, an exhaust connection, a cylinder-air supply connection, and a pilot control connection responsive to a change in fluidic pressure to switch said cylinder connection from communication with said cylinder-air connection to communication with said exhaust connection; means connecting said cylinder connections of said first and second pilot valve means to said first and second ports respectively; a source of cylinder-air connected to said cylinder-air supply connections of both of said first and second pilot valve means; first fluidic means responsive to simultaneous occurrence of substantially zero exhaust flow from said exhaust connections of said first and second pilot valve means to switch its output from a first position to a second position; second fluidic means having two output connections and two stable output states in one of which states the fluidic pressure at one of said two connections is high compared to that at the other of said two output connections and vice versa in the other of said two states; means responsive to each occurrence of said second output position of said first fluidic means to reverse the state of said second two-state fluidic means; and means connecting said output connections of said second two-state fluidic means to respective pilot control connections of said first and second pilot valve means to switch said first and second pilot valve means alternately at times determined by the times of said simultaneous occurrences of substantially zero exhaust flow.
Claim 3
Dependent Claim
33 words
The apparatus of claim 1, comprising means for delaying each said reversal of state of said second two-state fluidic means by a predetermined amount with respect to the times of said simultaneous occurrences.
Claim 4
Dependent Claim
16 words
The apparatus of claim 2, comprising single control means for adjusting the duration of said delay.