CA1155831A - Hydraulic jack with removable and serviceable pump and valve member - Google Patents
Hydraulic jack with removable and serviceable pump and valve memberInfo
- Publication number
- CA1155831A CA1155831A CA000371838A CA371838A CA1155831A CA 1155831 A CA1155831 A CA 1155831A CA 000371838 A CA000371838 A CA 000371838A CA 371838 A CA371838 A CA 371838A CA 1155831 A CA1155831 A CA 1155831A
- Authority
- CA
- Canada
- Prior art keywords
- pump
- unit
- cylinder
- chamber
- reservoir
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Expired
Links
Classifications
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B66—HOISTING; LIFTING; HAULING
- B66F—HOISTING, LIFTING, HAULING OR PUSHING, NOT OTHERWISE PROVIDED FOR, e.g. DEVICES WHICH APPLY A LIFTING OR PUSHING FORCE DIRECTLY TO THE SURFACE OF A LOAD
- B66F3/00—Devices, e.g. jacks, adapted for uninterrupted lifting of loads
- B66F3/24—Devices, e.g. jacks, adapted for uninterrupted lifting of loads fluid-pressure operated
- B66F3/25—Constructional features
- B66F3/42—Constructional features with self-contained pumps, e.g. actuated by hand
Abstract
HYDRAULIC JACK
ABSTRACT OF THE DISCLOSURE
A hydraulic jack comprises a piston and cylinder combination and a hydraulic fluid reservoir mounted on the piston and cylinder combination. There is a chamber between and communicating hydraulically with the piston and cylinder combination and the reservoir. A pump and valve unit is slidably received within the chamber. The unit comprises a pump conduit connecting the reservoir to the piston and cylinder combination, a pump for transferring fluid from the reservoir to the piston and cylinder combination through the pump conduit and a check valve for preventing a reverse flow of fluid from the piston and cylinder combination to the reservoir.
ABSTRACT OF THE DISCLOSURE
A hydraulic jack comprises a piston and cylinder combination and a hydraulic fluid reservoir mounted on the piston and cylinder combination. There is a chamber between and communicating hydraulically with the piston and cylinder combination and the reservoir. A pump and valve unit is slidably received within the chamber. The unit comprises a pump conduit connecting the reservoir to the piston and cylinder combination, a pump for transferring fluid from the reservoir to the piston and cylinder combination through the pump conduit and a check valve for preventing a reverse flow of fluid from the piston and cylinder combination to the reservoir.
Description
1 15~83 1 This invention relates to a hydraulic jack with a pump and valve unit releasably received between a piston and cylinder combination and a hydraulic fluid reservoir.
Ease of maintenance and simplicity of construction are of primary concern for hydraulic jacks in general and hydraulic camper jacks in particular. Hydraulic camper jacks are used for raising truck campers so that they can be removed from the backs of trucks or placed thereon.
Components such as O rings wear out as eventually do check valves and components of the pump. Earlier camper jacks have attempted to provide a construction allowing for easy serviceability of such items. However, previous jacks have not permitted access to all serviceable components, excluding the main piston and cylinder combination, with a single operation. Additionally, some prior jacks have relied upon threaded connections for hydraulic sealing which are prone to leaking and damage when the jacks are dis-assembled and assembled. Earlier jacks with even the simpler maintenance provisions require wrenches to gain access to the serviceable hydraulic parts.
In earlier patents, United States Patent 3,782,689 to Barosko discloses a combination valve and seal used in a hydraulic jack. United States Patent-3,350,063 to Thurlow and 4,015,822 to Rasmussen both disclose camper jacks.
United States Patent 3,985,389 to Bonfield discloses a hydraulic jack for use with wheel chairs.
Ring-type check valves for use in hydraulic systems are disclosed in United States Patent 2,790,597 to Turpin, 3,297,106 to Hanson, 3,298,394 to Chorkey, 3,303,910 to Gavillet, 3,511,271 to Pollinger and 3,618,690 to Johnson.
.~ ~
The invention is in a hydraulic device comprising a piston movable within a cylinder; a reservoir to contain hydraulic fluid; a pump to force fluid from the reservoir to the cylinder to move the piston within the cylinder;
S pump conduit means extending through the pump to allow hydraulic communication between the reservoir and the cy-linder; a reservoir conduit communicating the reservoir with an inlet for the pump conduit; a cylinder conduit communicating the cylinder with an outlet for the pump conduit; a first check valve to prevent reverse flow from the pump to the reservoir; a second check valve to prevent reverse flow from the cylinder to the pump and is the im-provement whereby the device has a chamber positioned be-tween the reservoir and the cylinder and the pump and the first and second check valves are formed in a single unit adapted to be a liquid-tight seal within the chamber; and releasable means to locate the single unit within the cham-ber, whereby the device may be serviced by removal of the releasable means, withdrawal of the single unit and re-20 placement with a complete single unit. `
Preferably, the chamber and the unit are cylin-drical and have generally equal diameters, the unit ex-tending through the chamber.
When compared with prior art hydraulic jacks, embodiments of the present invention offer distinct ad-vantages and surprising results. For example, by using the pump and valve unit, all serviceable components outside the main piston and cylinder combination can be removed from the jack with a single operation. The pump and valve unit can be retained within the jack by easily removable means such as C clips so that no wrenches are required for disassem-bly. The misuse of wrenches during disassembly and 1 ~5~83 1 assembly is a well known cause of damage to jacks. More-over, the use of the pump and valve unit means that all of the hydraulic sealing can be accomplished by reliable and serviceable means such as O rings. There is no need to rely upon threaded connections with their inherent tendency to leak. If desired, all hydraulic components of the camper jack, outside the main piston and cylinder combination, can be replaced in a single operation by the removal and re-placement of the pump and valve unit. However, when leaking occurs due to failure of the seals, all of the O rings can be replaced easily once the pump and valve unit is removed.
Figure 1 is a side elevational view of a camper jack according to an embodiment of the invention; and Figure 2 is a sectional view showing a portion of the jack of Figure 1, including the pump and valve unit, in elevation.
The drawings illustrate one embodiment of the invention which comprises a hydraulic camper jack 1 which is similar in overall configuration to earlier jacks used for the same purpose. The body of the jack includes the com-bination of the elongate hydraulic cylinder 2 and the piston 4. The piston 4 is an elongate rod which extends slidably through the aperture 6 in the bottom of the cylinder 2.
Hydraulic seals 8 are provided for hydraulic sealing about the piston 4 near the bottom of the cylinder 2. A stop-ring 9 prevents the piston 4 passing through aperture 6. The piston 4 is downwardly connected to the base plate 10 of the jack 1. An inner tube 13 is connected to base 10 and extends upwardly about cylinder 2. An outer tube 12 extends downwardly from the hydraulic fluid reservoir 14, on the top of the jack 1, and slidably about inner tube 13. Reservoir 14 is mounted on cylinder 2.
The ~ack 1 is raised by the action of pump 16, operated by the handle 18, which transfers hydraulic fluid downwardly from reservoir 14 to the cylinder 2. When it is desired to lower the jack, there is a release valve 20 which allows fluid to return from cylinder 2 to the reservoir 14 when opened. The jack 1 can be used to raise a Truck camper when one of the jacks is mounted on each corner of the camper by means of the bracket 22.
The jack 1 includes a cylindrical pump and valve unit 24 which is shown in better detail in Figure 2. The unit 24 is releasably received within the chamber 28 which comprises a cylindrical bore passing diametrically through the body 26 of the jack between the reservoir 14 and the cylinder 2. Unit 24 is secured in this position by the shoulder 30 which contacts the body 26 of the pump at one end of the chamber 28 and by the C clip 32 at the opposite end of the chamber.
The pump 16 comprises a pump cylinder 34 which extends axially into the member 24 from one end thereof. A
pump piston 36 is slidably received within cylinder 34 and the O ring 38, received within the annular groove 40 of the unit 24, provides sealing between the piston 36 and the cylinder 34. As seen in Figure 1, the handle 18 of the pump 16 is pivotally connected to the piston 36 by means of link 42 and a link pin 44. A link 46 and a pair of link pins 48 and 50 pivotally connect link 42 to the reservoir 14. As may be easily be appreciated, an upward movement of handle 18 moves piston 36 outwardly from cylinder 34, while a downward movement moves the piston into the cylinder.
Referring again to Figure 2, a conduit 52 in the body 26 of the pump 16 communicates upwardly with the hy-draulic fluid reservoir 14 and extends downwardly to the chamber 28. Similarly, a cylinder conduit 54 communicates downwardly with the interior of cylinder 2 and upwardly with the chamber 28. There is a pump conduit 56 through the member 24 which connects the reservoir 14 to the cylinder 2 by means of conduit 52 and conduit 54. Conduit 56 has a first end 57 which communicates with reservoir conduit 52 and a second end 59 which communicates with cylinder conduit 54.
Pump conduit 56 includes the bore 58, which passes diametrically through unit 24 and the axial bore 60 com-municating therewith. A larger axial bore 62 extends frombore 60 to the pump cylinder 34. A plurality of passageways 64 extend outwardly through unit 24 to the annular groove 66. Groove 66 communicating with the cylinder conduit 54.
Jack 1 has check valves for permitting the fluid to be pumped from reservoir 14 to the cylinder 2, but preventing the reverse flow of fluid. A first ball-type check valve 68 is operable between the pump 16 and the reservoir 14 to permit a flow of fluid from the reservoir to the pump. The ball of the check valve is biased against the 25 seat 70, formed between bore 60 and bore 62, by a coil spring 72 which is received within the groove 74 in bore 62.
A second, O ring-type check valve 76 comprises a resilient O
ring tightly received within the annular groove 66 of unit 24.
B
In operation, spring 72 normally keeps check valve 68 engaged with seat 70, but the suction within cylinder 34 when handle 18 is raised, and piston 36 moved outwardly, moves the check valve 68 inwardly against the pressure of the spring 72 and permits hydraulic fluid to pass from reservoir 14 downwardly through conduit 52 and in-to the cylinder 34 through pump conduit 56. An upward flow of fluid from cylinder 2 and conduit 54 is prevented by check valve 76 which is sucked inwardly to seal the passageways 64 when the handle is raised. When the handle 18 is subse-quently pushed downwardly, moving piston 36 towards check valve 68, the ball is forced against seat 70 and prevents the fluid from returning to reservoir 14. However, the pre-ssure of fluid as piston 36 moves inwardly expands check valve 76 so it is raised away from passageways 64 and allows the hydraulic fluid to flow from pump 16 to cylinder
Ease of maintenance and simplicity of construction are of primary concern for hydraulic jacks in general and hydraulic camper jacks in particular. Hydraulic camper jacks are used for raising truck campers so that they can be removed from the backs of trucks or placed thereon.
Components such as O rings wear out as eventually do check valves and components of the pump. Earlier camper jacks have attempted to provide a construction allowing for easy serviceability of such items. However, previous jacks have not permitted access to all serviceable components, excluding the main piston and cylinder combination, with a single operation. Additionally, some prior jacks have relied upon threaded connections for hydraulic sealing which are prone to leaking and damage when the jacks are dis-assembled and assembled. Earlier jacks with even the simpler maintenance provisions require wrenches to gain access to the serviceable hydraulic parts.
In earlier patents, United States Patent 3,782,689 to Barosko discloses a combination valve and seal used in a hydraulic jack. United States Patent-3,350,063 to Thurlow and 4,015,822 to Rasmussen both disclose camper jacks.
United States Patent 3,985,389 to Bonfield discloses a hydraulic jack for use with wheel chairs.
Ring-type check valves for use in hydraulic systems are disclosed in United States Patent 2,790,597 to Turpin, 3,297,106 to Hanson, 3,298,394 to Chorkey, 3,303,910 to Gavillet, 3,511,271 to Pollinger and 3,618,690 to Johnson.
.~ ~
The invention is in a hydraulic device comprising a piston movable within a cylinder; a reservoir to contain hydraulic fluid; a pump to force fluid from the reservoir to the cylinder to move the piston within the cylinder;
S pump conduit means extending through the pump to allow hydraulic communication between the reservoir and the cy-linder; a reservoir conduit communicating the reservoir with an inlet for the pump conduit; a cylinder conduit communicating the cylinder with an outlet for the pump conduit; a first check valve to prevent reverse flow from the pump to the reservoir; a second check valve to prevent reverse flow from the cylinder to the pump and is the im-provement whereby the device has a chamber positioned be-tween the reservoir and the cylinder and the pump and the first and second check valves are formed in a single unit adapted to be a liquid-tight seal within the chamber; and releasable means to locate the single unit within the cham-ber, whereby the device may be serviced by removal of the releasable means, withdrawal of the single unit and re-20 placement with a complete single unit. `
Preferably, the chamber and the unit are cylin-drical and have generally equal diameters, the unit ex-tending through the chamber.
When compared with prior art hydraulic jacks, embodiments of the present invention offer distinct ad-vantages and surprising results. For example, by using the pump and valve unit, all serviceable components outside the main piston and cylinder combination can be removed from the jack with a single operation. The pump and valve unit can be retained within the jack by easily removable means such as C clips so that no wrenches are required for disassem-bly. The misuse of wrenches during disassembly and 1 ~5~83 1 assembly is a well known cause of damage to jacks. More-over, the use of the pump and valve unit means that all of the hydraulic sealing can be accomplished by reliable and serviceable means such as O rings. There is no need to rely upon threaded connections with their inherent tendency to leak. If desired, all hydraulic components of the camper jack, outside the main piston and cylinder combination, can be replaced in a single operation by the removal and re-placement of the pump and valve unit. However, when leaking occurs due to failure of the seals, all of the O rings can be replaced easily once the pump and valve unit is removed.
Figure 1 is a side elevational view of a camper jack according to an embodiment of the invention; and Figure 2 is a sectional view showing a portion of the jack of Figure 1, including the pump and valve unit, in elevation.
The drawings illustrate one embodiment of the invention which comprises a hydraulic camper jack 1 which is similar in overall configuration to earlier jacks used for the same purpose. The body of the jack includes the com-bination of the elongate hydraulic cylinder 2 and the piston 4. The piston 4 is an elongate rod which extends slidably through the aperture 6 in the bottom of the cylinder 2.
Hydraulic seals 8 are provided for hydraulic sealing about the piston 4 near the bottom of the cylinder 2. A stop-ring 9 prevents the piston 4 passing through aperture 6. The piston 4 is downwardly connected to the base plate 10 of the jack 1. An inner tube 13 is connected to base 10 and extends upwardly about cylinder 2. An outer tube 12 extends downwardly from the hydraulic fluid reservoir 14, on the top of the jack 1, and slidably about inner tube 13. Reservoir 14 is mounted on cylinder 2.
The ~ack 1 is raised by the action of pump 16, operated by the handle 18, which transfers hydraulic fluid downwardly from reservoir 14 to the cylinder 2. When it is desired to lower the jack, there is a release valve 20 which allows fluid to return from cylinder 2 to the reservoir 14 when opened. The jack 1 can be used to raise a Truck camper when one of the jacks is mounted on each corner of the camper by means of the bracket 22.
The jack 1 includes a cylindrical pump and valve unit 24 which is shown in better detail in Figure 2. The unit 24 is releasably received within the chamber 28 which comprises a cylindrical bore passing diametrically through the body 26 of the jack between the reservoir 14 and the cylinder 2. Unit 24 is secured in this position by the shoulder 30 which contacts the body 26 of the pump at one end of the chamber 28 and by the C clip 32 at the opposite end of the chamber.
The pump 16 comprises a pump cylinder 34 which extends axially into the member 24 from one end thereof. A
pump piston 36 is slidably received within cylinder 34 and the O ring 38, received within the annular groove 40 of the unit 24, provides sealing between the piston 36 and the cylinder 34. As seen in Figure 1, the handle 18 of the pump 16 is pivotally connected to the piston 36 by means of link 42 and a link pin 44. A link 46 and a pair of link pins 48 and 50 pivotally connect link 42 to the reservoir 14. As may be easily be appreciated, an upward movement of handle 18 moves piston 36 outwardly from cylinder 34, while a downward movement moves the piston into the cylinder.
Referring again to Figure 2, a conduit 52 in the body 26 of the pump 16 communicates upwardly with the hy-draulic fluid reservoir 14 and extends downwardly to the chamber 28. Similarly, a cylinder conduit 54 communicates downwardly with the interior of cylinder 2 and upwardly with the chamber 28. There is a pump conduit 56 through the member 24 which connects the reservoir 14 to the cylinder 2 by means of conduit 52 and conduit 54. Conduit 56 has a first end 57 which communicates with reservoir conduit 52 and a second end 59 which communicates with cylinder conduit 54.
Pump conduit 56 includes the bore 58, which passes diametrically through unit 24 and the axial bore 60 com-municating therewith. A larger axial bore 62 extends frombore 60 to the pump cylinder 34. A plurality of passageways 64 extend outwardly through unit 24 to the annular groove 66. Groove 66 communicating with the cylinder conduit 54.
Jack 1 has check valves for permitting the fluid to be pumped from reservoir 14 to the cylinder 2, but preventing the reverse flow of fluid. A first ball-type check valve 68 is operable between the pump 16 and the reservoir 14 to permit a flow of fluid from the reservoir to the pump. The ball of the check valve is biased against the 25 seat 70, formed between bore 60 and bore 62, by a coil spring 72 which is received within the groove 74 in bore 62.
A second, O ring-type check valve 76 comprises a resilient O
ring tightly received within the annular groove 66 of unit 24.
B
In operation, spring 72 normally keeps check valve 68 engaged with seat 70, but the suction within cylinder 34 when handle 18 is raised, and piston 36 moved outwardly, moves the check valve 68 inwardly against the pressure of the spring 72 and permits hydraulic fluid to pass from reservoir 14 downwardly through conduit 52 and in-to the cylinder 34 through pump conduit 56. An upward flow of fluid from cylinder 2 and conduit 54 is prevented by check valve 76 which is sucked inwardly to seal the passageways 64 when the handle is raised. When the handle 18 is subse-quently pushed downwardly, moving piston 36 towards check valve 68, the ball is forced against seat 70 and prevents the fluid from returning to reservoir 14. However, the pre-ssure of fluid as piston 36 moves inwardly expands check valve 76 so it is raised away from passageways 64 and allows the hydraulic fluid to flow from pump 16 to cylinder
2 through the annular groove 66 and cylinder conduit 54.
Jack 1 includes seals between the unit 24 and the cylindrical chamber 28 to prevent a leakage of hydraulic fluid during the pumping operation. The seals consist of three resilient O rings 78, 80 and 82 received within the annular grooves 84, 86 and 88 of unit 24 respectively. Seals 78 and 80 are to each side of the first end 57 of pump conduit 56. Similarly, seals 80 and 82 are to each side of the second end 59 of conduit 56.
In order to lower jack 1, it is provided with the release valve 20 which has a threaded portion 94 threadedly received within the correspondingly tapped portion 96 of the axial bore 98 extending inwardly from the end of unit 24 opposite the pump 16. When the valve 20 is tightened in the bore 98, its portion 99 sealingly engages the seat 100 formed in the bore while its portion 101 engages seat 103 of the bore. Bore 98 forms part of a release conduit 102, also formed by diametrical bores 104 and 106 in unit 24. Bore 104 communicates upwardly with reservoir 14 by means of reservoir conduit 108, while bore 106 communicates down-wardly with cylinder 2 by means of cylinder conduit 110.
Normally, valve 20 is tightened against seats 100 and 103 to prevent fluid from flowing upwardly from cylinder 2 to reservoir 14 through the release conduit 102. However, when it is desired to lower the jack, valve 20 is unscrewed slightly, permitting a flow of fluid to pass upwardly through conduit 110 and bore 106 past valve 20 and upwardly to the reservoir 14.
O rings 112 and 114 received within annular grooves 116 and 118 of unit 24 provide seals between the unit 24 and chamber 28 to either side of the first end 120 of release conduit 102 which communicates with reservoir conduit 108. Similarly, O ring 114 and O ring 78 provide seals on opposite sides of the second end 122 of reIease conduit 122 which communicates with cylinder conduit 110.
To prevent unwanted movement downwardly of plate 10 a safety catch may be provided. The catch comprises a stud 121 to receive an angle member 122. Foot 124 of angle member 122 fits beneath plate 10. Angle member 122 is retained in position by, for example, a wing nut 126 en-gaging stud 121. When nut 126 is removed angle member 122 may be removed from stud 121 and the jack can then be operated.
The jack is simple to operate. When the truck E:
camper is stopped first the release valves 20 are slackened slightly on the jacks attached to the truck camper. As each valve 20 is opened base 10 is moved downwardly, for example with the foot, to contact a solid base, for example the ground. Each jack should be left about 30 seconds after base 10 has been moved to allow liquid in the reservoir to move into the cylinder 2 to establish equilibrium. When equilibrium is established valves 20 are closed and the jacks operated by moving handles 18. As indicated above this transfers hydraulic fluid from reservoir 14 to cylinder 2. Pressure within cylinder 2 is increased causing lifting of the cylinder 2 about the piston 4 to raise the jack, and then the camper attached to each bracket 22. The jacks are lowered by opening valves 20.
~ When it is desired to remove unit 24 for inspec-tion or servicing, it is simply necessary to remove C clip 32 and valve 20. Once this is accomplished, unit 24 can be removed from the body 26 of jack 1 by a sliding movement outwardly in the direction of pump 16. It should be em-phasized that the jack need not be removed from the truckcamper. Access to such components as the O rings, check valves 76 and 68 and the pump 16 is accomplished simulta-neously. The entire unit 24 can be easily replaced if desired or separate components such as the O rings can be replaced readily. No tools are required for this disassem-bly or the reassembly.
When compared with prior art jacks, the preferred embodiment of the present invention offers a considerably simplified hydraulic arrangement with improved service-ability. Moreover, the use of such features has the ring-type check valve 76 improves the economy and reliability of the jack when compared with earlier devices.
Jack 1 includes seals between the unit 24 and the cylindrical chamber 28 to prevent a leakage of hydraulic fluid during the pumping operation. The seals consist of three resilient O rings 78, 80 and 82 received within the annular grooves 84, 86 and 88 of unit 24 respectively. Seals 78 and 80 are to each side of the first end 57 of pump conduit 56. Similarly, seals 80 and 82 are to each side of the second end 59 of conduit 56.
In order to lower jack 1, it is provided with the release valve 20 which has a threaded portion 94 threadedly received within the correspondingly tapped portion 96 of the axial bore 98 extending inwardly from the end of unit 24 opposite the pump 16. When the valve 20 is tightened in the bore 98, its portion 99 sealingly engages the seat 100 formed in the bore while its portion 101 engages seat 103 of the bore. Bore 98 forms part of a release conduit 102, also formed by diametrical bores 104 and 106 in unit 24. Bore 104 communicates upwardly with reservoir 14 by means of reservoir conduit 108, while bore 106 communicates down-wardly with cylinder 2 by means of cylinder conduit 110.
Normally, valve 20 is tightened against seats 100 and 103 to prevent fluid from flowing upwardly from cylinder 2 to reservoir 14 through the release conduit 102. However, when it is desired to lower the jack, valve 20 is unscrewed slightly, permitting a flow of fluid to pass upwardly through conduit 110 and bore 106 past valve 20 and upwardly to the reservoir 14.
O rings 112 and 114 received within annular grooves 116 and 118 of unit 24 provide seals between the unit 24 and chamber 28 to either side of the first end 120 of release conduit 102 which communicates with reservoir conduit 108. Similarly, O ring 114 and O ring 78 provide seals on opposite sides of the second end 122 of reIease conduit 122 which communicates with cylinder conduit 110.
To prevent unwanted movement downwardly of plate 10 a safety catch may be provided. The catch comprises a stud 121 to receive an angle member 122. Foot 124 of angle member 122 fits beneath plate 10. Angle member 122 is retained in position by, for example, a wing nut 126 en-gaging stud 121. When nut 126 is removed angle member 122 may be removed from stud 121 and the jack can then be operated.
The jack is simple to operate. When the truck E:
camper is stopped first the release valves 20 are slackened slightly on the jacks attached to the truck camper. As each valve 20 is opened base 10 is moved downwardly, for example with the foot, to contact a solid base, for example the ground. Each jack should be left about 30 seconds after base 10 has been moved to allow liquid in the reservoir to move into the cylinder 2 to establish equilibrium. When equilibrium is established valves 20 are closed and the jacks operated by moving handles 18. As indicated above this transfers hydraulic fluid from reservoir 14 to cylinder 2. Pressure within cylinder 2 is increased causing lifting of the cylinder 2 about the piston 4 to raise the jack, and then the camper attached to each bracket 22. The jacks are lowered by opening valves 20.
~ When it is desired to remove unit 24 for inspec-tion or servicing, it is simply necessary to remove C clip 32 and valve 20. Once this is accomplished, unit 24 can be removed from the body 26 of jack 1 by a sliding movement outwardly in the direction of pump 16. It should be em-phasized that the jack need not be removed from the truckcamper. Access to such components as the O rings, check valves 76 and 68 and the pump 16 is accomplished simulta-neously. The entire unit 24 can be easily replaced if desired or separate components such as the O rings can be replaced readily. No tools are required for this disassem-bly or the reassembly.
When compared with prior art jacks, the preferred embodiment of the present invention offers a considerably simplified hydraulic arrangement with improved service-ability. Moreover, the use of such features has the ring-type check valve 76 improves the economy and reliability of the jack when compared with earlier devices.
Claims (12)
1. In a hydraulic device comprising:
a piston movable within a cylinder;
a reservoir to contain hydraulic fluid;
a pump to force fluid from the reservoir to the cylinder to move the piston within the cylinder;
pump conduit means extending through the pump to allow hydraulic communication between the reservoir and the cylinder;
a reservoir conduit communicating the reservoir with an inlet for the pump conduit;
a cylinder conduit communicating the cylinder with an outlet for the pump conduit;
a first check valve to prevent reverse flow from the pump to the reservoir;
a second check valve to prevent reverse flow from the cylinder to the pump;
the improvement whereby:
the device has a chamber positioned between the reservoir and the cylinder and the pump and the first and second check valves are formed in a single unit adapted to be a liquid-tight seal within the chamber; and releasable means to locate the single unit within the chamber, whereby the device may be serviced by removal of the releasable means, withdrawal of the single unit and replacement with a complete single unit.
a piston movable within a cylinder;
a reservoir to contain hydraulic fluid;
a pump to force fluid from the reservoir to the cylinder to move the piston within the cylinder;
pump conduit means extending through the pump to allow hydraulic communication between the reservoir and the cylinder;
a reservoir conduit communicating the reservoir with an inlet for the pump conduit;
a cylinder conduit communicating the cylinder with an outlet for the pump conduit;
a first check valve to prevent reverse flow from the pump to the reservoir;
a second check valve to prevent reverse flow from the cylinder to the pump;
the improvement whereby:
the device has a chamber positioned between the reservoir and the cylinder and the pump and the first and second check valves are formed in a single unit adapted to be a liquid-tight seal within the chamber; and releasable means to locate the single unit within the chamber, whereby the device may be serviced by removal of the releasable means, withdrawal of the single unit and replacement with a complete single unit.
2. A device as claimed in claim 1, the chamber extending transversely through the device.
3. A device as claimed in claim 2, the chamber and the unit being cylindrical and having generally equal diameters, the unit extending through the chamber.
4. A device as claimed in claim 3, including annular grooves formed in the unit;
O rings housed within the annular grooves to pro-ject slightly above the surface of the unit to provide the necessary liquid-tight seal within the chamber.
O rings housed within the annular grooves to pro-ject slightly above the surface of the unit to provide the necessary liquid-tight seal within the chamber.
5. A device as claimed in claim 4, the second check valve comprising an o ring between the single unit and the chamber adjacent the cylinder conduit, the pump conduit extending outwardly through the unit to the second check valve, the second check valve being normally in sealing engagement with the pump conduit and being outwardly ex-pandable to permit fluid to flow from the pump to the cy-linder conduit.
6. A device as claimed in claim 1, the unit having two ends, the pump being near one end.
7. A device as claimed in claim 1, the unit including a release valve for permitting fluid to return from the cylinder to the reservoir.
8. A device as claimed in claim 7, the release valve being operable along a release conduit in the unit communicating at a first end with the chamber and the re-servoir and at a second end with the chamber and the cy-linder.
9. A device as claimed in claim 1, the unit being releasable from the chamber by sliding movement to-wards one end thereof.
10. A device as claimed in claim 1, the relea-sable means to locate the single unit within the chamber comprising a shoulder on the unit for abutting engagement at one end of the chamber and a C clip engageable with the unit at an end of the chamber opposite the one end.
11. A device as claimed in claim 1, the pump comprising a pump cylinder extending axially into the unit from one end thereof and communicating with the pump conduit, and a piston slidably received in the pump cylinder.
12. A device as claimed in claim 11, the release valve being near an end of the unit opposite the one end thereof.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CA000371838A CA1155831A (en) | 1981-02-26 | 1981-02-26 | Hydraulic jack with removable and serviceable pump and valve member |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CA000371838A CA1155831A (en) | 1981-02-26 | 1981-02-26 | Hydraulic jack with removable and serviceable pump and valve member |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CA1155831A true CA1155831A (en) | 1983-10-25 |
Family
ID=4119316
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CA000371838A Expired CA1155831A (en) | 1981-02-26 | 1981-02-26 | Hydraulic jack with removable and serviceable pump and valve member |
Country Status (1)
| Country | Link |
|---|---|
| CA (1) | CA1155831A (en) |
Cited By (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN103318802A (en) * | 2013-07-02 | 2013-09-25 | 平湖市通力机械有限公司 | Disconnect-type oil jack |
| CN106726372A (en) * | 2016-12-29 | 2017-05-31 | 桂林电子科技大学 | One kind replaces walking frame, wheeled walking frame and wheelchair |
| CN110053590A (en) * | 2019-03-28 | 2019-07-26 | 杭州恒宏机械有限公司 | Hydraulic pressure lifting device for pulling type lodging vehicle |
-
1981
- 1981-02-26 CA CA000371838A patent/CA1155831A/en not_active Expired
Cited By (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN103318802A (en) * | 2013-07-02 | 2013-09-25 | 平湖市通力机械有限公司 | Disconnect-type oil jack |
| CN106726372A (en) * | 2016-12-29 | 2017-05-31 | 桂林电子科技大学 | One kind replaces walking frame, wheeled walking frame and wheelchair |
| CN106726372B (en) * | 2016-12-29 | 2023-04-28 | 桂林电子科技大学 | Alternate walking frame, wheel type walking frame and wheelchair |
| CN110053590A (en) * | 2019-03-28 | 2019-07-26 | 杭州恒宏机械有限公司 | Hydraulic pressure lifting device for pulling type lodging vehicle |
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