Device for controlling the reciprocation of a working piston

Claim 1

A device for reciprocating the working piston of a pneumatic drive unit comprising, in combination, a directional control valve with three ports and a control element movable between two distinct positions, with a first port being connected to a source of air under pressure, a second port being connected to atmosphere, and said movable control element being selectively operable to connect the third port to either said first port or said second port; a compressed air storage container; a control block connected to both said directional control valve and said container; said pneumatic drive unit including a cylinder and a working piston therein dividing said cylinder into first and second cylinder chambers; said control block being formed with first and second interior chambers and with a first passage connecting said first interior chamber to said second interior chamber and terminating in a first connection port of said control block; a first connection line connecting said first connection port to said first cylinder chamber; a hollow rod movable axially in said first interior chamber and having an outer end projecting externally from said control block and formed with a cross bore connecting the interior of said hollow rod, at its outer end, with atmosphere; a flexible diaphragm secured to the periphery of said rod and secured in said first interior chamber to divide said first interior chamber into pressure chambers on opposite sides of said flexible diaphragm; means in said first interior chamber defining an inlet chamber surrounding the inner end of said hollow rod; a second passage formed in said block and connecting said inlet chamber to a second connection port; a second connection line connecting said second connection port to said third port of said directional control valve; a main valve axially displaceable in said inlet chamber adjacent the inner end of said hollow rod; biasing means biasing said main valve in a direction to engage the inner end of said hollow rod to close said inner end; said block being formed with a first axial passage through which said hollow rod extends to define an annular main flow passage connecting said inlet chamber to said first passage, said main flow passage being closed by said main valve, under the influence of said biasing means, when said hollow rod is in a position in which its inner end is retracted inwardly beyond the adjacent end of said first axial passage to disengage said main valve; a third passage connecting said second passage to said first interior chamber on that side of said diaphragm nearer to the outer end of said hollow rod; said diaphragm being flexed, to shift said hollow rod axially, in accordance with the differential between the pressures in said pressure chambers on said opposite sides of said flexible diaphragm; said rod being movable to an end position wherein said main valve closes said first axial passage and the inner end of said hollow rod is disengaged from said main valve to connect the interior of said hollow rod with said first passage through said first axial passage to vent said first passage to atmosphere through said cross bore; a solid rod mounted for axial displacement in said second interior chamber; a cup-shaped secondary valve secured to said solid rod for movement therewith; a frustoconical insert in said second interior chamber surrounding said solid rod and defining therewith a second annular passage communicating at one end with said first passage; said frustoconical insert being formed with a radial passage therethrough closed by said cup-shaped secondary valve in a first position of said solid rod; a tubular piece in said second intErior chamber in axially spaced relation to said insert and defining, with said solid rod, a third annular axial passage; the space between said frustoconical insert and said tubular piece defining a cavity communicating with said second and third annular axial passages; a third passage communicating with said cavity and terminating in a third connection port; a third connection line connecting said third connection port to said second cylinder chamber; a fourth connection port communicating with said second interior chamber exteriorly of said frustoconical insert; a fourth connection line connecting said fourth connection port to said compressed air storage container; means, including said control block, defining a cover chamber having a vent to atmosphere and surrounding the end of said solid rod extending from said third annular passage; a valve plate on said last-named end of said solid rod in said cover chamber movable with said solid rod to close said third annular axial passage in a second position of said solid rod in which said cupshaped secondary valve uncovers said radial passage; and a valve seat defined in said control block between said first passage and said second interior chamber and engaged by said cup-shaped valve, in said second position of said solid rod, to block communication between said first passage and said second interior chamber and thus to block communication between said first passage and said compressed air storage container; whereby, upon movement of the control element of said directional control valve to a position connecting the first port of said directional control valve to its third port, fluid under pressure is supplied through said third passage to deflect said diaphragm to move said hollow rod in a direction to engage said main valve and to displace said main valve away from said second axial passage for flow of fluid under pressure from said second passage through said inlet chamber to said first passage and thus to said first cylinder chamber to displace said piston axially of said cylinder in a working stroke and, when said control element of said directional control valve is moved to its opposite position to connect the second port of said directional control valve to its third port, said second and third passages are connected to atmosphere to relieve the pressure on said diaphragm for flexing of said diaphragm in a direction to disengage said hollow rod from said main valve for seating of said main valve on the end of said second axial passage and establishment of communication between said first passage and the interior of said hollow rod for venting of the pressure in said first cylinder chamber to atmosphere through said hollow rod with the pressure in said compressed air storage container being effective in said second cylinder chamber to displace said piston toward said first cylinder chamber in an idle stroke; said frustoconical valve, during the working stroke of said piston, occupying a position connecting said first passage through said fourth connection port for supply of fluid under pressure to said compressed air storage container, as a valve plate opening said third annular axial passage for connection of said second cylinder chamber to said cover chamber for venting of the pressure in said second cylinder chamber to atmosphere through said vent, said control block is formed with a fourth passage connecting said cavity to that one of said pressure chambers on the side of said diaphragm more remote from the outer end of said hollow rod.

Claim 2

A device for reciprocating the working piston of a pneumatic drive unit comprising, in combination, a directional control valve with three ports and a control element movable between two distinct positions, with a first port being connected to a source of air under pressure, a second port being connected to atmosphere, and said movable control element being selectively operable to connect the third port to either said first port or said second port; a compressed air storage container; a control block connected to both said directional control valve and said container; said pneumatic drive unit including a cylinder and a working piston therein dividing said cylinder into first and second cylinder chambers; said control block being formed with first and second interior chambers and with a first passage connecting said first interior chamber to said second interior chamber and terminating in a first connection port of said control block; a first connection line connecting said first connection port to said first cylinder chamber; a hollow rod movable axially in said first interior chamber and having an outer end projecting externally from said control block and formed with a cross bore connecting the interior of said hollow rod, at its outer end, with atmosphere; a flexible diaphragm secured to the periphery of said rod and secured in said first interior chamber to divide said first interior chamber into pressure chambers on opposite sides of said flexible diaphragm; means in said first interior chamber defining an inlet chamber surrounding the inner end of said hollow rod; a second passage formed in said block and connecting said inlet chamber to a second connection port; a second connection line connecting said second connection port to said third port of said directional control valve; a main valve axially displaceable in said inlet chamber adjacent the inner end of said hollow rod; biasing means biasing said main valve in a direction to engage the inner end of said hollow rod to close said inner end; said block being formed with a first axial passage through which said hollow rod extends to define an annular main flow passage connecting said inlet chamber to said first passage, said main flow passage being closed by said main valve, under the influence of said biasing means, when said hollow rod is in a position in which its inner end is retracted inwardly beyond the adjacent end of said first axial passage to disengage said main valve; a third passage connecting said second passage to said first interior chamber on that side of said diaphragm nearer to the outer end of said hollow rod; said diaphragm being flexed, to shift said hollow rod axially, in accordance with the differential between the pressures in said pressure chambers on said opposite sides of said flexible diaphragm; said rod being movable to an end position wherein said main valve closes said first axial passage and the inner end of said hollow rod is disengaged from said main valve to connect the interior of said hollow rod with said first passage through said first axial passage to vent said first passage to atmosphere through said cross bore; a solid rod mounted for axial displacement in said second interior chamber; a cup-shaped secondary valve secured to said solid rod for movement therewith; a frustoconical insert in said second interior chamber surrounding said solid rod and defining therewith a second annular passage communicating at one end with said first passage; said frustoconical insert being formed with a radial passage therethrough closed by said cup-shaped secondary valve in a first position of said solid rod; a tubular piece in said second intErior chamber in axially spaced relation to said insert and defining, with said solid rod, a third annular axial passage; the space between said frustoconical insert and said tubular piece defining a cavity communicating with said second and third annular axial passages; a third passage communicating with said cavity and terminating in a third connection port; a third connection line connecting said third connection port to said second cylinder chamber; a fourth connection port communicating with said second interior chamber exteriorly of said frustoconical insert; a fourth connection line connecting said fourth connection port to said compressed air storage container; means, including said control block, defining a cover chamber having a vent to atmosphere and surrounding the end of said solid rod extending from said third annular passage; a valve plate on said last-named end of said solid rod in said cover chamber movable with said solid rod to close said third annular axial passage in a second position of said solid rod in which said cupshaped secondary valve uncovers said radial passage; and a valve seat defined in said control block between said first passage and said second interior chamber and engaged by said cup-shaped valve, in said second position of said solid rod, to block communication between said first passage and said second interior chamber and thus to block communication between said first passage and said compressed air storage container; whereby, upon movement of the control element of said directional control valve to a position connecting the first port of said directional control valve to its third port, fluid under pressure is supplied through said third passage to deflect said diaphragm to move said hollow rod in a direction to engage said main valve and to displace said main valve away from said second axial passage for flow of fluid under pressure from said second passage through said inlet chamber to said first passage and thus to said first cylinder chamber to displace said piston axially of said cylinder in a working stroke and, when said control element of said directional control valve is moved to its opposite position to connect the second port of said directional control valve to its third port, said second and third passages are connected to atmosphere to relieve the pressure on said diaphragm for flexing of said diaphragm in a direction to disengage said hollow rod from said main valve for seating of said main valve on the end of said second axial passage and establishment of communication between said first passage and the interior of said hollow rod for venting of the pressure in said first cylinder chamber to atmosphere through said hollow rod with the pressure in said compressed air storage container being effective in said second cylinder chamber to displace said piston toward said first cylinder chamber in an idle stroke; said frustoconical valve, during the working stroke of said piston, occupying a position connecting said first passage through said fourth connection port for supply of fluid under pressure to said compressed air storage container, as a valve plate opening said third annular axial passage for connection of said second cylinder chamber to said cover chamber for venting of the pressure in said second cylinder chamber to atmosphere through said vent, said control block is formed with a fourth passage connecting said cavity to that one of said pressure chambers on the side of said diaphragm more remote from the outer end of said hollow rod.

Claim 6

A device for reciprocating the working piston of a pneumatic drive unit comprising, in combination, a directional control valve with three ports and a control element movable between two distinct positions, with a first port being connected to a source of air under pressure, a second port being connected to atmosphere, and said control element being selectively operable to connect the third port to either said first port or said second port; a compressed air storage container, a control block connected to both said control valve and said container; said pneumatic drive unit including a cylinder and a working piston therein dividing said cylinder into first and second cylinder chambers; said control block being formed with a main conduit therein extending between a first connection port and a second connection port; a first connection line connecting said first connection port to said first cylinder chamber; a second connection line connecting said second connection port to the third port of said directional control valve; said main conduit having a relatively larger diameter portion intermediate its ends serving as a main valve chamber; a main valve shutter mounted in said main valve chamber for axial displacement therein between a first end position, in which said shutter clears said main conduit, and a second end position in which said shutter engages a circular main valve seat formed in said main valve chamber to block said main conduit; a spring biasing said shutter to said second end position, said shutter being displaceable to said first end position against the bias of said spring; a hollow rod mounted in said control block in fluid-tight relation and extending axially of said circular main valve seat; the outer end of said hollow rod projecting externally said control block and being open to the atmosphere; said hollow rod being displaceable between a first end position in which its open inner end extends through said circular main valve seat and engages said main valve shutter to retain said shutter in its first end position against the bias of said spring; said hollow rod being displaceable to a second end position in which it disengages said main valve shutter so that said shutter is biased against said circular main valve seat by said spring to block said main conduit and with the open inner end of said hollow rod communicating with that portion of said main conduit leading to said first connection port; said control block being formed with a secondary conduit therein extending between a third connection port and a fourth connection port; a third connection line connecting said third connection port to said second cylinder chamber; a fourth connection line connecting said fourth connection port to said compressed air storage container; said secondary conduit having an increased diameter portion intermediate its ends defining a secondary valve chamber; the portion of said secondary conduit opening into said secondary valve chamber adjacent said main conduit being shaped as a tapered annular secondary valve seat; the wall of said secondary valve chamber opposite said secondary valve seat terminating at an opening into said main conduit; a cap-shaped seal, having its periphery in the form of an elastic lip, mounted in said secondary valve chamber for coaxial displacement relative to said secondary valve seat; said cap-shaped seal having a first end position in which it tightly engages said secondary valve seat to block said secondary conduit while clearing communication between said main conduit aNd said fourth connection port, and having a second end position in which said cap-shaped seal is displaced from said secondary valve seat to clear said secondary conduit with the periphery of said cap-shaped seal tightly engaging the wall of said secondary valve chamber to block communication between said main conduit and said secondary conduit; said control block being formed with a by-pass conduit open at one end to atmosphere and communicating at its opposite end with that portion of said secondary conduit communicating with said third connection port; said by-pass conduit having disposed therein a check valve formed by a circular check valve seat and a check valve shutter; said check valve shutter being mounted on one end portion of a solid rod axially displaceable in said secondary valve chamber and having an opposite end connected to said cap-shaped seal so that, in said first end position of said cap-shaped seal, said check valve is open and, in said second and position of said cap-shaped seal, said check valve is closed; said hollow rod extending through a control chamber formed in said control block; an elastic diaphragm secured to said hollow rod in said control chamber and extending radially of said hollow rod with its periphery sealed to said control block; said elastic diaphragm defining said control chamber into two compartments; said control block being formed with a passage therein connecting that one of said two compartments which is nearer to the outer end of said hollow rod directly to said second connection line; said control block being formed with a further passage connecting the other of said two compartments directly with that portion of said secondary conduit extending to said third connection port; whereby, responsive to the pressure in one of said two compartments exceeding the pressure in the other of said two compartments, said hollow rod is displaced into a selected one of its respective end positions; said cap-shaped seal, in its first end position, establishing communication between said main conduit and said compressed air storage container and, in its second end position, blocking communication between said main conduit and said compressed air storage container; said one of said two compartments, when said control element of said directional control valve connects said third port of said directional control valve to said first port thereof, being subjected to the pressure of said source of fluid under pressure and, when said control element of said directional control valve connects said third port to said second port, being connected to atmosphere; said other of said two compartments, being constantly subjected to the pressure of the air in said compressed air storage container.

Claim 7

A device for reciprocating the working piston of a pneumatic drive unit comprising, in combination, a directional control valve with three ports and a control element movable between two distinct positions, with a first port being connected to a source of air under pressure, a second port being connected to atmosphere, and said control element being selectively operable to connect the third port to either said first port or said second port; a compressed air storage container, a control block connected to both said control valve and said container; said pneumatic drive unit including a cylinder and a working piston therein dividing said cylinder into first and second cylinder chambers; said control block being formed with a main conduit therein extending between a first connection port and a second connection port; a first connection line connecting said first connection port to said first cylinder chamber; a second connection line connecting said second connection port to the third port of said directional control valve; said main conduit having a relatively larger diameter portion intermediate its ends serving as a main valve chamber; a main valve shutter mounted in said main valve chamber for axial displacement therein between a first end position, in which said shutter clears said main conduit, and a second end position in which said shutter engages a circular main valve seat formed in said main valve chamber to block said main conduit; a spring biasing said shutter to said second end position, said shutter being displaceable to said first end position against the bias of said spring; a hollow rod mounted in said control block in fluid-tight relation and extending axially of said circular main valve seat; the outer end of said hollow rod projecting externally said control block and being open to the atmosphere; said hollow rod being displaceable between a first end position in which its open inner end extends through said circular main valve seat and engages said main valve shutter to retain said shutter in its first end position against the bias of said spring; said hollow rod being displaceable to a second end position in which it disengages said main valve shutter so that said shutter is biased against said circular main valve seat by said spring to block said main conduit and with the open inner end of said hollow rod communicating with that portion of said main conduit leading to said first connection port; said control block being formed with a secondary conduit therein extending between a third connection port and a fourth connection port; a third connection line connecting said third connection port to said second cylinder chamber; a fourth connection line connecting said fourth connection port to said compressed air storage container; said secondary conduit having an increased diameter portion intermediate its ends defining a secondary valve chamber; the portion of said secondary conduit opening into said secondary valve chamber adjacent said main conduit being shaped as a tapered annular secondary valve seat; the wall of said secondary valve chamber opposite said secondary valve seat terminating at an opening into said main conduit; a cap-shaped seal, having its periphery in the form of an elastic lip, mounted in said secondary valve chamber for coaxial displacement relative to said secondary valve seat; said cap-shaped seal having a first end position in which it tightly engages said secondary valve seat to block said secondary conduit while clearing communication between said main conduit aNd said fourth connection port, and having a second end position in which said cap-shaped seal is displaced from said secondary valve seat to clear said secondary conduit with the periphery of said cap-shaped seal tightly engaging the wall of said secondary valve chamber to block communication between said main conduit and said secondary conduit; said control block being formed with a by-pass conduit open at one end to atmosphere and communicating at its opposite end with that portion of said secondary conduit communicating with said third connection port; said by-pass conduit having disposed therein a check valve formed by a circular check valve seat and a check valve shutter; said check valve shutter being mounted on one end portion of a solid rod axially displaceable in said secondary valve chamber and having an opposite end connected to said cap-shaped seal so that, in said first end position of said cap-shaped seal, said check valve is open and, in said second and position of said cap-shaped seal, said check valve is closed; said hollow rod extending through a control chamber formed in said control block; an elastic diaphragm secured to said hollow rod in said control chamber and extending radially of said hollow rod with its periphery sealed to said control block; said elastic diaphragm defining said control chamber into two compartments; said control block being formed with a passage therein connecting that one of said two compartments which is nearer to the outer end of said hollow rod directly to said second connection line; said control block being formed with a further passage connecting the other of said two compartments directly with that portion of said secondary conduit extending to said third connection port; whereby, responsive to the pressure in one of said two compartments exceeding the pressure in the other of said two compartments, said hollow rod is displaced into a selected one of its respective end positions; said cap-shaped seal, in its first end position, establishing communication between said main conduit and said compressed air storage container and, in its second end position, blocking communication between said main conduit and said compressed air storage container; said one of said two compartments, when said control element of said directional control valve connects said third port of said directional control valve to said first port thereof, being subjected to the pressure of said source of fluid under pressure and, when said control element of said directional control valve connects said third port to said second port, being connected to atmosphere; said other of said two compartments, being constantly subjected to the pressure of the air in said compressed air storage container.