Hydraulic cartridge for improved motion control

A hydraulic cartridge of the type having a body supporting a sealed enclosure containing fluid, said enclosure containing a high pressure chamber and low pressure reservoir space, a reciprocative plunger having a working stroke and a first portion external of said enclosure adapted to receive actuating loads, said plunger having a second portion connected to the first portion and extending within the enclosure, there being a fluid seal encircling said plunger between said first and second portions, said second portion extending through a primary part of the reservoir space to the high pressure chamber and forming a movable barrier between the high pressure chamber and said primary part of the reservoir space to resist movement of the plunger, wherein the improvement comprises:

• a cylinder having intrinsically a wall with inner and outer surfaces and first and second open ends, a tubular jacket member secured to the cylinder having intrinsically one open muzzle end and one end at least partially enclosed, said jacket encircling a portion of the length of said cylinder, a closure member for the second end of said cylinder retained by said jacket, there being passage means for flow of fluid from said high pressure chamber between the jacket and cylinder to permit movement of said plunger, a flexible expandable bladder forming a variable volume secondary part of the reservoir space, the bladder having a first and second anchor portions respectively encircling portions of said cylinder and jacket thereby enclosing the muzzle end of the jacket within the secondary part of the reservoir space and means sealing said anchor portions of said cylinder and jacket, said first anchor portion of said bladder being adjacent the first end of said cylinder, the cylinder being provided with an internal circumferential groove, a cylinder closure member for said first end of the cylinder provided with bearing means for guiding said plunger, said cylinder closure member for the first end of the cylinder being retained in said cylinder by a snap ring engaged in said circumferential groove, said cylinder closure member for the first end of the cylinder having an end flange extending radially beyond the outer diameter of said bladder first anchor portion to retain said bladder, said snap ring being disengageable by axial pressure applied to said end flange.

A hydraulic cartridge of the type having a body supporting a sealed enclosure containing fluid, said enclosure containing a high pressure chamber and low pressure reservoir space, a reciprocative plunger having a working stroke and a first portion external of said enclosure adapted to receive actuating loads, said plunger having a second portion connected to the first portion and extending within the enclosure, there being a fluid seal encircling said plunger between said first and second portions, said second portions extending through a primary part of the reservoir space to the high pressure chamber and forming a movable barrier between the high pressure chamber and said primary part of the reservoir space to resist movement of the plunger, wherein the improvement comprises:

• a cylinder having intrinsically a wall with inner and outer surfaces and first and second open ends, a tubular jacket member secured to the cylinder having intrinsically one open muzzle end and one end at least partially enclosed, said jacket encircling a portion of the length of said cylinder, a closure for the second end of said cylinder retained by said jacket, there being passage means for flow of fluid from said high pressure chamber between the jacket and cylinder to permit movement of said plunger, a flexible expandable bladder forming a variable volume secondary part of the reservoir space, the bladder having first and second anchor portions respectively encircling portions of said cylinder and jacket thereby enclosing the muzzle end of the jacket within the secondary part of the reservoir space and means sealing said anchor portions to said cylinder and jacket, said first anchor portion of the bladder being adjacent the first end of the cylinder, a first clamp ring constricting said first anchor portion into tight contact with the cylinder, a cylinder closure member retained in the first end of the cylinder, said cylinder closure member retained in the said first end of the cylinder having an end flange extending radially beyond the inner diameter of said first clamp ring thereby to retain said clamp ring in place.

A hydraulic cartridge of the type having a body supporting a sealed enclosure containing fluid, said enclosure containing a high pressure chamber and low pressure reservoir space, a reciprocative plunger having a working stroke and a first portion external of said enclosure adapted to receive actuating loads, said plunger having a second portion connected to the first portion and extending within the enclosure, there being a fluid seal encircling said plunger between said first and second portions, said second portion extending through a primary part of the reservoir space to the high pressure chamber and forming a movable barrier between the high pressure chamber and said primary part of the reservoir space to resist movement of the plunger, wherein the improvement comprises:

• a cylinder having intrinsically a wall with inner and outer surfaces and first and second open ends, a tubular jacket member secured to the cylinder having intrinsically one open muzzle end and one end at least partially enclosed, said jacket encircling a portion of the length of said cylinder, a closure for the second end of said cylinder retained by said jacket, there being passage means for flow of fluid from said high pressure chamber between the jacket and cylinder to permit movement of said plunger, a flexible expandable bladder forming a variable volume secondary part of the reservoir space, the bladder having first and second anchor portions respectively encircling portions of said cylinder and jacket thereby enclosing the muzzle end of the jacket within the secondary part of the reservoir space, and means sealing said anchor portions to said cylinder and jacket, said movable barrier comprising a piston larger in diameter than the adjacent part of said plunger, said plunger seal being a diaphragm having an invaginable wall with one end attached to the plunger, said diaphragm having a rim portion annular in shape, an annular quill member and a piston stop ring member secured within said cylinder confining, pressurizing, and sealing said rim portion therebetween against the inner wall of said cylinder, said quill member having a bore supporting said invaginable wall against the fluid, said piston stop ring providing means to limit the stroke of said plunger.

A hydraulic cartridge of the type having a body supporting a sealed enclosure containing fluid, said enclosure containing a high pressure chamber and low pressure reservoir space, a reciprocative plunger having a working stroke and a first portion external of said enclosure adapted to receive actuating loads, said plunger having a second portion connected to the first portion and extending within the enclosure, there being a fluid seal encircling said plunger between said first and second portions, said second portion extending through a primary part of the reservoir space to the high pressure chamber and forming a movable barrier between the high pressure chamber and said primary part of the reservoir space to resist movement of the plunger, wherein the improvement comprises:

• a cylinder having intrinsically a wall with inner and outer surfaces and first and second open ends, a tubular jacket member having a muzzle end circumferentially open to fluid flow, said jacket being secured to the cylinder closely spaced from said outer cylinder surface throughout a major portion of its interior length including its muzzle end, said jacket having one end at least partially enclosed, a closure for the second end of said cylinder retained by said jacket, there being passage means for fluid to flow from said high pressure chamber between the jacket and cylinder to said reservoir space to permit movement of said plunger, a flexible elastomeric bladder having induced circumferential tension forming a variable volume secondary part of the reservoir space and maintaining reserve pressure in the fluid tending to extrude said plunger, the bladder having first and second anchor portions respectively encircling portions of said cylinder and jacket thereby enclosing the muzzle end of the jacket within the secondary part of the reservoir space, and means sealing said anchor portions to said cylinder and jacket, said movable barrier comprising a piston larger in diameter than the adjacent part of said plunger, said plunger seal being a diaphragm having an invaginable wall with one end attached to the plunger, said diaphragm having a rim portion annular in shape, an annular structure and a shaped annular ring member secured within said cylinder confining, pressurizing, and sealing said rim portion therebetween against the inner wall of said cylinder, said annular structure having a bore supporting said invaginable wall against the fluid, said shaped annular ring member providing means to limit the stroke of said plunger.

A hydraulic cartridge of the type having a body supporting a sealed enclosure containing fluid, said enclosure containing a high pressure chamber and low pressure reservoir space, a reciprocative plunger having a working stroke and a first portion external of said enclosure adapted to receive actuating loads, said plunger having a second portion connected to the first portion and extending within the enclosure, there being a fluid seal encircling said plunger between said first and second portions, said second portion extending through a primary part of the reservoir space to the high pressure chamber and forming a movable barrier between the high pressure chamber and said primary part of the reservoir space to resist movement of the plunger, wherein the improvement comprises:

• a cylinder having intrinsically a wall with inner and outer surfaces and first and second open ends, said first end extending beyond said fluid seal and being devoid of fluid, a tubular jacket member having a muzzle end circumferentially open to fluid flow, said jacket being secured to the cylinder closely spaced from said cylinder outer surface throughout a major portion of its interior length including its muzzle end, said jacket having one end at least partially enclosed, a closure for the second end of said cylinder retained by said jacket, there being passage means for fluid to flow from said high pressure chamber between the jacket and cylinder to said reservoir space to permit movement of said plunger, a flexible elastomeric bladder having induced circumferential tension forming a variable volume secondary part of the reservoir space and maintaining reserve pressure in the fluid tending to extrude said plunger, the bladder having first and second anchor portions respectively encircling portions of said cylinder and jacket thereby enclosing the muzzle end of the jacket within the secondary part of the reservoir space and means sealing said anchor portions to said cylinder and jacket, said first anchor portion of the bladder being sealed in position adjacent the first end of said cylinder, a closure member fitting slidably within said cylinder adjacent said first end, said closure member adjacent said first end having an end flange extending radially into sealing contact with said first anchor portion of the bladder.

A hydraulic cartridge of the type having a body supporting a sealed enclosure containing fluid, said enclosure containing a high pressure chamber and low pressure reservoir space, a reciprocative plunger having a working stroke and a first portion external of said enclosure adapted to receive actuating loads, said plunger having a second portion connected to the first portion and extending within the enclosure, there being a fluid seal encircling said plunger between said first and second portions, said second portion extending through a primary part of the reservoir space to the high pressure chamber and forming a movable barrier between the high pressure chamber and said primary part of the reservoir space to resist movement of the plunger, wherein the improvement comprises:

• a cylinder having intrinsically a wall with inner and outer surfaces and first and second open ends, a tubular jacket member having a muzzle end circumferentially open to fluid flow, said jacket being secured to the cylinder closely spaced from said outer cylinder surface throughout a major portion of its interior length including its muzzle end, said jacket having one end at least partially enclosed, a closure for the second end of said cylinder retained by said jacket, there being passage means for fluid to flow from said high pressure chamber between the jacket and cylinder to said reservoir space to permit movement of said plunger, a flexible elastomeric bladder having induced circumferential tension forming a variable volume secondary part of the reservoir space and maintaining reserve pressure in the fluid tending to extrude said plunger, the bladder having first and second anchor portions respectively encircling portions of said cylinder and jacket thereby enclosing the muzzle end of the jacket within the secondary part of the reservoir space, and first and second clamp rings sealing said first and second anchor portions respectively to said cylinder and jacket.

A hydraulic cartridge of the type having a body supporting a sealed enclosure containing fluid, said enclosure containing a high pressure chamber and low pressure reservoir space, a reciprocative plunger having a working stroke and a first portion external of said enclosure adapted to receive actuating loads, said plunger having a second portion connected to the first portion and extending within the enclosure, there being a fluid seal encircling said plunger between said first and second portions, said second portion extending through a primary part of the reservoir space to the high pressure chamber and forming a movable barrier between the high pressure chamber and said primary part of the reservoir space to resist movement of the plunger, wherein the improvement comprises:

• a cylinder having intrinsically a wall with inner and outer surfaces and first and second open ends, a tubular jacket member secured to the cylinder having intrinsically one open muzzle end and one end at least partially enclosed, said jacket encircling a portion of the length of said cylinder, a closure for the second end of said cylinder retained by said jacket, there being passage means for flow of fluid from said high pressure chamber between the jacket and cylinder to permit movement of said plunger, a flexible expandable bladder forming a variable volume secondary part of the reservoir space, the bladder having first and second anchor portions respectively encircling portions of said cylinder and jacket thereby enclosing the muzzle end of the jacket within the secondary part of the reservoir space, and means sealing said anchor portions to said cylinder and jacket, there being a discontinuous external circumferential shoulder extending radially outward from the outer surface of the cylinder, the muzzle end of the jacket contacting said flange and forming a passageway communicating with flow passages leading from the high pressure chamber and the primary and secondary reservoir spaces.

A hydraulic cartridge of the type having a body supporting a sealed enclosure containing fluid, said enclosure containing a high pressure chamber and low pressure reservoir space, a reciprocative plunger having a working stroke and a first portion external of said enclosure adapted to receive actuating loads, said plunger having a second portion connected to the first portion and extending within the enclosure, there being a fluid seal encircling said plunger between said first and second portions, said second portion extending through a primary part of the reservoir space to the high pressure chamber and forming a movable barrier between the high pressure chamber and said primary part of the reservoir space to resist movement of the plunger, wherein the improvement comprises:

• a cylinder having intrinsically a wall with inner and outer surfaces and first and second open ends, a tubular metallic jacket member having an intrinsically open muzzle end, said jacket encircling a portion of the length of said cylinder and being secured to the cylinder closely spaced from said outer cylinder surface throughout a major portion of its length, said jacket having an outer circumferential wall extending throughout a major portion of its length forming a portion of the exterior wall of said cartridge, said jacket having one end at least partially enclosed, closure means for the second end of said cylinder retained by said jacket, a tubular flexible elastomeric bladder surrounding a portion of said cylinder in tandem to said jacket and forming a variable volume secondary part of the reservoir space, said bladder having induced circumferential tension maintaining reserve pressure in the fluid tending to extrude the plunger, said bladder having first and second end portions respectively sealed to said cylinder and jacket, there being passage means which, during each working stroke, channel fluid to flow from said high pressure chamber between the jacket and cylinder, then to enter the bladder to permit movement of said plunger, said fluid seal encircling said plunger being a diaphragm having an invaginable wall with one end attached to the plunger, said diaphragm having a rim portion annular in shape, an annular structure secured within said cylinder confining, pressuring, and sealing said rim portion against the inner wall of said cylinder, said annular structure having a bore supporting said invaginable wall against the fluid.

A hydraulic cartridge of the type having a body supporting a sealed enclosure containing fluid, said enclosure containing a high pressure chamber and low pressure reservoir space, a reciprocative plunger having a working stroke and a first portion external of said enclosure adapted to receive actuating loads, said plunger having a second portion connected to the first portion and extending within the enclosure, there being a fluid seal encircling said plunger between said first and second portions, said second portion extending through a primary part of the reservoir space to the high pressure chamber and forming a movable barrier between the high pressure chamber and said primary part of the reservoir space to resist movement of the plunger, wherein the improvement comprises:

• a cylinder having intrinsically a wall with inner and outer surfaces and first and second open ends, a tubular flexible elastomeric bladder surrounding a portion of said cylinder forming a variable volume part of said sealed enclosure and forming a secondary part of the reservoir space, said bladder having induced circumferential tension maintaining reserve pressure in the fluid tending to extend the plunger, there being passage means, which during each working stroke, channel fluid to flow from said high pressure chamber into said bladder to permit movement of said plunger, said fluid seal encircling said plunger being a diaphragm having an invaginable wall with one end attached to the plunger, said diaphragm having a rim portion annular in shape, an annular structure secured within said cylinder confining, pressuring, and sealing said rim portion against the inner wall of said cylinder, said annular structure having a bore supporting said invaginable wall against the fluid, there being check valve means within said high pressure chamber comprising a seat area, a movable valve element and a closing spring for the movable valve element for permitting fast flow of fluid from said reservoir space to said high pressure chamber for quick plunger return, and an encasement structure surrounding said bladder and having an impervious wall, sealing means contacting said encasement and forming an airtight chamber around said bladder, said encasement being provided with an air inlet port adapted for connection to an air conduit to permit air pressure to be brought to bear against the exterior of said bladder, said bladder having an amount of induced circumferential tension which maintains reserve fluid pressure slightly above that necessary to prevent relaxation and wrinkling of the diaphragm but insufficient to open the check valve and extend the plunger, the said seat area and closing spring force against the movable valve element being correlated with said induced circumferential tension of the bladder to effect opening of said valve at a fluid pressure slightly higher than that maintained by said bladder, said air inlet port permitting introduction of air pressure to compress said bladder to augment said reserve pressure sufficiently to open the check valve and extrude the plunger.