US20020170423A1 - Hydraulic tool with an oc/cc selector - Google Patents
Hydraulic tool with an oc/cc selector Download PDFInfo
- Publication number
- US20020170423A1 US20020170423A1 US09/858,905 US85890501A US2002170423A1 US 20020170423 A1 US20020170423 A1 US 20020170423A1 US 85890501 A US85890501 A US 85890501A US 2002170423 A1 US2002170423 A1 US 2002170423A1
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- Prior art keywords
- chamber
- mode
- piston
- tool
- hydraulic
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Classifications
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- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F15—FLUID-PRESSURE ACTUATORS; HYDRAULICS OR PNEUMATICS IN GENERAL
- F15B—SYSTEMS ACTING BY MEANS OF FLUIDS IN GENERAL; FLUID-PRESSURE ACTUATORS, e.g. SERVOMOTORS; DETAILS OF FLUID-PRESSURE SYSTEMS, NOT OTHERWISE PROVIDED FOR
- F15B13/00—Details of servomotor systems ; Valves for servomotor systems
- F15B13/02—Fluid distribution or supply devices characterised by their adaptation to the control of servomotors
- F15B13/021—Valves for interconnecting the fluid chambers of an actuator
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- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F15—FLUID-PRESSURE ACTUATORS; HYDRAULICS OR PNEUMATICS IN GENERAL
- F15B—SYSTEMS ACTING BY MEANS OF FLUIDS IN GENERAL; FLUID-PRESSURE ACTUATORS, e.g. SERVOMOTORS; DETAILS OF FLUID-PRESSURE SYSTEMS, NOT OTHERWISE PROVIDED FOR
- F15B11/00—Servomotor systems without provision for follow-up action; Circuits therefor
- F15B11/02—Systems essentially incorporating special features for controlling the speed or actuating force of an output member
- F15B11/024—Systems essentially incorporating special features for controlling the speed or actuating force of an output member by means of differential connection of the servomotor lines, e.g. regenerative circuits
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- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F15—FLUID-PRESSURE ACTUATORS; HYDRAULICS OR PNEUMATICS IN GENERAL
- F15B—SYSTEMS ACTING BY MEANS OF FLUIDS IN GENERAL; FLUID-PRESSURE ACTUATORS, e.g. SERVOMOTORS; DETAILS OF FLUID-PRESSURE SYSTEMS, NOT OTHERWISE PROVIDED FOR
- F15B15/00—Fluid-actuated devices for displacing a member from one position to another; Gearing associated therewith
- F15B15/20—Other details, e.g. assembly with regulating devices
- F15B15/202—Externally-operated valves mounted in or on the actuator
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- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F15—FLUID-PRESSURE ACTUATORS; HYDRAULICS OR PNEUMATICS IN GENERAL
- F15B—SYSTEMS ACTING BY MEANS OF FLUIDS IN GENERAL; FLUID-PRESSURE ACTUATORS, e.g. SERVOMOTORS; DETAILS OF FLUID-PRESSURE SYSTEMS, NOT OTHERWISE PROVIDED FOR
- F15B21/00—Common features of fluid actuator systems; Fluid-pressure actuator systems or details thereof, not covered by any other group of this subclass
- F15B21/08—Servomotor systems incorporating electrically operated control means
- F15B21/082—Servomotor systems incorporating electrically operated control means with different modes
Abstract
Description
- 1. Field of the Invention
- This invention relates to hydraulic tools, and more particularly to hydraulic tools that can use a constant pressure fluid delivery system or a constant volume fluid delivery system. In particular, this invention relates to a hydraulic tool having a selector sleeve that is selectively adjustable to operate the tool in an “open center” (OC) mode or a “closed center” (CC) mode.
- 2. Description of Related Art
- U.S. Pat. No. 5,778,755 is directed to a control apparatus22 for operating a
hydraulic tool 20 that can use a constant volume or constant pressure fluid system. The constant volume or OC mode of operation is shown in FIGS. 1-3, and the constant pressure or CC mode of operation is shown in FIGS. 4 and 5. - The control apparatus22 includes a housing 32 having a cavity 34 in which a piston 36 reciprocates. The piston 36 divides the cavity 34 into a drive chamber 44, which is positioned to the left of the piston 36, and a
retract chamber 42, which is positioned to the right of the piston 36. Anadjustment assembly 48 is retained in the drive chamber 44 to control fluid flow between theretract chamber 42 and the drive chamber 44 in a neutral mode. The control apparatus 22 also includes a handle structure 49 containing a valve assembly 50. Inlet and outlet ports 52, 54 can be connected to a constant volume or constant pressure fluid source. A central port 56 selectively connects the inlet port 52 with theretract chamber 42. A cross port 58 communicates with the drive chamber 44 and selectively with the outlet port 54. - The piston36 includes a plurality of shuttle valves 66 having shuttle spools 68 that are retained in shuttle ports 70 formed in the piston 36. Enlarged heads 72, 74 are provided on each end of the shuttle spool 68. Each shuttle valve 66 operates along a valve axis 78 that is generally parallel to the central axis 76.
- The
adjustment assembly 48 allows the control apparatus to be operated in the OC or CC mode. Theadjustment assembly 48 includes a control body or annular member 82 which is attached to adjustment shafts 84 extending through a shaft bore 86 in the housing 32. The control body 82 can be moved between a first position (FIGS. 1-3) and a second position (FIGS. 4 and 5) by use of drive heads 96 that are connected to the adjustment shafts 84, and are accessible to the outside of the housing 32. In the first position, the control body 82 extends away from a recess 106, and in the second position, the control body 82 is received within the recess 106. The control body 82 has an annular shape that provides a continuous circumferential contact surface 102 that can contact the shuttle valves 66 (FIG. 1) regardless of their circumferential orientation. - When the
adjustment assembly 48 is configured for use with a constant volume system, the shuttle valves 66 are moved as a result of contacting theadjustment assembly 48 when the piston 36 is retracted. Movement of the spool valves 66 unseats valve heads 74 from the shuttle port 70. By disengaging the heads 74 fluid flows from theretract chamber 42 to the drive chamber 44 when the piston is in a neutral position as shown in FIG. 1. As shown in FIG. 4, the adjustment assembly is spaced away from the spool valves 66 for use with a constant pressure system thereby preventing engagement with the shuttle spool valve 66 causing the spool valve heads 74 to seal the shuttle port 70 when the piston 36 is in a neutral position. - A step-by-step description of the operation is now described. In FIG. 1, the
adjustment assembly 48 is positioned in the constant volume or OC mode. The piston 36 is in the fully retracted position in which the shuttle valves 66 are opened by contact of the head 72 against the control body 82. This neutral position allows fluid to continuously flow from the inlet port 52, through the control apparatus 22 (i.e., the central port 56, tubular conduit 108,retract chamber 42, and around valve spools 66), and back through the outlet port 54 via cross port 58. - In FIG. 2, trigger64 is actuated to communicate the inlet port 52 with the cross port 58, which in turn supplies pressurized fluid to the drive chamber 44 to drive the piston 36. During this movement, the heads 72 are maintained in their position against the piston. Fluid from the
retract chamber 42 is exhausted through the central conduit 108, the central port 56 and the outlet port 54. - In FIG. 3, the trigger64 has been released following a crimping operation. Release of the trigger 64 re-establishes communication between the inlet port 52 and the central port, central conduit 108 and the
retract chamber 42 to slide the piston 36 to its retracted position. During this movement, the spool valves 66 slide on the piston 36 so that the heads 74 contact the piston 36, until such time as the piston reaches the fully retracted position. At that time, the heads 72 engage the control body 82, and the heads 74 are separated from the piston 36 to allow pressurized fluid to pass though the piston 36 and to the outlet port 54 via the cross port 58. - The closed volume or CC mode of operation is shown in FIGS. 4 and 5. The only difference in these figures is that the control body82 has been placed in the recess 106 so that it does not contact the heads 74 when the tool is in the neutral position (FIG. 4). As such, the pressurized fluid (that is supplied via the inlet port 52, central conduit 56 and tubular conduit 108) is maintained in the
retract chamber 42 and does not pass through the piston 36. - The operation of the tool in the CC mode in FIG. 5 is the same as the operation of the tool in the OC mode in FIG. 2. Further, when the trigger is released, the shuttle valves66 will slide such that heads 74 contact the piston 36. However, upon reaching the fully retracted position, the heads 72 will not contact the control body 82 so that constant pressure is maintained on the piston 36.
- U.S. Pat. No. 5,442,992 patent discloses a reciprocating
hydraulic tool 20 in the form of a shade tree pruner. Thetool 20 includes acylinder 40 having a piston 34 that reciprocates between a fully extended position and a retracted position. Thetool 20 is referred to in the art as a “pull to cut” tool since the blades 26, 28 of the pruner start in the open position, and when the trigger 90 is actuated, hydraulic fluid is supplied to the side of the piston 34 remote from the trigger 90. This causes the piston to move toward the trigger, and the blade 26 is pulled toward the blade 28 to perform a cutting operation. - The
tool 20 can use either a constant pressure (CC) or a constant volume (OC) source of hydraulic fluid. A selector 60 is rotatably mounted on the cylinder to enable the tool to be used in the OC or CC modes. FIGS. 1 and 2 show the selector 60 in the OC mode, and FIGS. 3 and 4 show the selector in the CC mode. - In FIGS. 1 and 2, the selector60 defines a passageway 62 that communicates between opposite sides of the piston 34 when the piston is in its fully advanced position with respect to the cylinder, as shown in FIG. 1. In this fully advanced position, the piston is fully advanced with respect to the end 58 of the cylinder which is opposite its end 44 at which the
valve body 42 is coupled. - In the second position of the selector60 as illustrated in FIGS. 3 and 4, the passage 62 is rotated out of a position for communicating between the opposite sides of the piston 34. Additionally, the passage 62 mounts a one-way check valve 68 that limits fluid flow to a single direction, from a side 70 of the piston 34 that faces the first end 44 of the cylinder and the opposite side 56 of the piston that faces the opposite end 58 of the
cylinder 40. - In FIGS. 1 and 3, the
tool 20 is in the neutral position. Hydraulic fluid is supplied by the pressure port 49 to a cross port 52 that supplies the fluid to thecylinder 40, which is maintained in the fully extended position. Fluid from the opposite side of the piston is exhausted through the conduit 54, short port 55 and outlet port 51. - In FIG. 1, the selector60 is positioned such that, when the piston is in the fully extended position, the fluid can enter the passageway 62 of the selector 60, pass through holes 64 and 66 in the
cylinder 40, the check valve 68, and return to the conduit 54 and outlet port 51. This is the OC mode of operation. - FIG. 3 differs in this respect because the selector60 is rotated so that the passageway 62 does not align with the holes 64, 66 of the
cylinder 40, which disables communication between the opposite ends of the piston 34. Therefore, fluid is supplied to the cross port 52 and the left side of the piston, while fluid from the right side of the piston is exhausted. This is the CC mode of operation. - In FIGS. 2 and 4, the trigger has been actuated to perform a cutting operation. Fluid is supplied to the conduit54, which in turn provides the fluid to the side 56 of the piston 34 that is remote from the trigger. At the same time, fluid is exhausted (via cross port 52, axial port 92, and outlet port 50) from the side 70 of the piston that faces the trigger. This causes the piston to move toward the trigger.
- As opposed to FIGS. 2 and 4 (the CC mode), the selector60 in FIGS. 1 and 3 (the OC mode) is positioned so that fluid can flow from the holes 64, 66 into the passageway 62. However, the ball 80 of the check valve 68 is maintained in the closed position by use of a spring 82.
- The 755 and 992 patents are complicated in design and require that a short circuit for the OC mode of operation be provided by using a passage in or around the piston. Thus, a need has developed in the art to provide a hydraulic tool in which modification of the piston and/or the cylindrical housing is not necessary to short circuit flow in the OC mode of operation.
- One aspect of the invention is to provide a hydraulic tool having a selector member that can be switched easily between the OC and CC modes of operation. The tool may be a reciprocating tool such as a crimper, but it is not limited to reciprocating type tools.
- Another aspect of the invention is to provide a hydraulic tool, which is preferably piston actuated, in which a short circuiting hole or conduit can be provided in an oil tube that communicates between the valve spool and a side of the piston opposite the oil tube. The short circuiting hole or conduit can be provided such that fluid need not go around, through or even reach the piston and/or a cylinder that houses the piston.
- According to one exemplary embodiment of the invention, a hydraulic tool switchable between an open center mode and a closed center mode and having a work mode and a neutral mode comprises a cylinder defining a chamber, a piston within the chamber and operable in the neutral mode and the work mode, the piston defining a drive chamber and a retract chamber within the chamber, a valve operable to selectively supply hydraulic fluid to the drive chamber to thereby drive the piston to a first position when the tool is in the work mode, and to selectively supply the hydraulic fluid to the retract chamber to thereby move the piston to a second position when the tool is in the neutral mode, a fluid inlet and a fluid outlet in fluid communication with the valve; an oil tube in fluid communication with the valve and extending through the piston and being in communication with the retract chamber, the oil tube including opposite ends and at least one hole between said ends, and a mode selector being positionable between a first position in which the tool can operate in the open center mode in which the tool can utilize a constant volume fluid delivery source, and a second position in which the tool can operate in the closed center mode in which the tool can utilize a constant pressure fluid delivery source. In the open center work mode the valve is configured to supply the hydraulic fluid through the oil tube to the drive chamber to drive the piston to the first position. When the tool is moved to the neutral mode, the valve is configured to supply the hydraulic fluid through the oil tube to the retract chamber such that movement of the piston to the second piston can allow communication between the inlet and outlet through the at least one hole in the oil tube.
- According to another exemplary embodiment of the invention, a hydraulic tool comprises a cylinder defining a chamber and a piston within the chamber and operable in a neutral mode and a work mode, the piston defining a drive chamber and a retract chamber within the chamber. A valve is operable to selectively supply hydraulic fluid to the drive chamber to thereby drive the piston when the tool is in the work mode, and to selectively supply the hydraulic fluid to the retract chamber when the tool is in the neutral mode. A mode selector member is positionable between a first position in which the tool can operate in an open center mode in which the tool can utilize a constant volume fluid delivery source, and a second position in which the tool can operate in a closed center mode in which the tool can utilize a constant pressure fluid delivery source. In the open center mode when the tool is in the neutral mode, the valve is configured to supply the hydraulic fluid to the retract chamber until filled, whereupon any excess hydraulic fluid is exhausted to an outlet port before it reaches the chamber or the piston.
- In yet another exemplary embodiment of the invention, a hydraulic tool comprises a cylinder defining a chamber, a piston within the chamber and operable in a neutral mode and a work mode, the piston defining a drive chamber and a retract chamber within the chamber, and a valve operable to selectively supply hydraulic fluid to the drive chamber to thereby drive the piston when the tool is in the work mode, and to selectively supply the hydraulic fluid to the retract chamber when the tool is in the neutral mode. The tool can operate in a open center mode in which the tool can utilize a constant volume fluid delivery source. In the open center mode when the tool is in the neutral mode, the spool is configured to supply the hydraulic fluid to the retract chamber until filled, whereupon any excess hydraulic fluid is exhausted to the outlet port before it reaches the chamber or the piston.
- These and other aspects of the invention will be described in or become apparent from the following detailed description of preferred embodiments.
- Preferred embodiments of the invention will be described in conjunction with reference to the following drawings, in which like reference numbers indicate like parts, wherein:
- FIG. 1 illustrates a side view of a hydraulic tool in the CC mode of operation and in the neutral position, according to one preferred embodiment of the invention;
- FIG. 2 illustrates the hydraulic tool in the CC mode of operation, as shown in FIG. 1, but in the working position;
- FIG. 3 illustrates a side view of a hydraulic tool in the OC mode of operation and in the neutral position; and
- FIG. 4 illustrates the hydraulic tool in the OC mode of operation, as shown in FIG. 3, but in the working position.
- FIGS.1-4 show one example of a
tool 100 that can use either a constant pressure on a constant volume source of hydraulic fluid. In this example, thetool 100 is a reciprocating type tool, although other tools, for example, of the non-reciprocating type, are also within the scope the disclosure. FIGS. 1 and 2 illustrate the CC mode of operation, while FIGS. 3 and 4 illustrate the OC mode of operation. FIGS. 1 and 3 illustrate the neutral position of thetool 100, while FIGS. 2 and 4 illustrate the working position of thetool 100. - As shown in FIG. 1, the
tool 100 includes a housing 1 defining a chamber in which apiston 2 reciprocates. Amode selector 5 is preferably in the form of a sleeve that is coupled, e.g., using threads, to a portion, e.g. an interior portion, of the housing 1. A valve handle 25 is coupled to themode selector sleeve 5, e.g., using acoupling element 40 that includes aflange 41 for engaging aradial protrusion 42 formed as part of or connected to thevalve handle 25. Thecoupling member 40 can be threadedly coupled to an exterior surface of aflange 43 formed on themode selector sleeve 5. - The valve handle25 includes a
valve spool 14 that communicates aninlet port 16 and anoutlet port 15. Thevalve spool 14 includes aspool shaft 14 a that is axially slidable within the valve handle 25 upon selective activation of atrigger 20. When thetrigger 20 is activated, the inlet andoutlet ports central port 29 and across port 31, using channels that are formed in theslidable spool shaft 14 a. The valve handle 25 also includes anend 30 that is adapted to receive one end of anoil tube 6. The end of theoil tube 6 is press-fit into theend 30 of thevalve handle 25 and communicates with thecentral port 29. Theoil tube 6 includes at least one hole orpassage 12. Asleeve valve 9 is slidably fitted over theoil tube 6. Thesleeve valve 9 includes at least one passage orhole 9 a that is selectively alignable with at least one passage orhole 12 in theoil tube 6 as will be described. Thehole 9 a is associated with aball valve 10 that allows one-way flow of pressurized fluid as will be described. - A
coil spring 13 is mounted in surrounding relation to an exterior surface of theoil tube 6. Thespring 13 has a first end that abuts against theend 30 of thevalve handle 25, and a second end which rests against a portion of thesleeve valve 9 that faces theend 30 of thevalve handle 25. Thespring 13 tends to bias thesleeve valve 9 towards and/or against a retainingring 27 fixed on an inside surface of themode selector sleeve 5. Thesleeve valve 9 includes aforward extension 45 positioned toward thepiston 2, for selective interaction therewith in accordance with the position of themode selector sleeve 5, are explained more fully below. - The cylinder1 defines a
drive chamber 4 to the right side of the piston 2 (or the side of thepiston 2 facing theextension 45 of the sleeve valve 9), and a retractchamber 3 to the left side of thepiston 2. The positions of the drive and retract chambers could be reversed, if desired. Areciprocating ram 18 fitted within an end of the housing 1 is connected to and moves with thepiston 2. Theram 18 includes abore 7 in which a distal portion of theoil tube 6 is positioned. Theram 18 includes at least oneopening 8 that communicates fluid between the retractchamber 3 and anend 46 of theoil tube 6. - The
mode selector sleeve 5 is moveable, e.g. rotatable, with respect to the housing 1 to thereby create axial displacement between the housing 1 and themode selector sleeve 5. Theselector sleeve 5 can move between the closed center positions shown in FIGS. 1 and 2 and the open center positions shown in FIGS. 3 and 4. Axial movement of themode selector sleeve 5 also causes commensurate axial movement of the valve handle 25 (via coupling sleeve 40) and theoil tube 6 relative to housing 1. Thesleeve valve 9 is also axially displaceable with theoil tube 6 upon rotation of theselector sleeve 5, but thesleeve valve 9 reaches its maximum axial displacement when thesleeve valve 9 engages the retainingring 27. That is, while thesleeve valve 9 can slide axially with respect to theoil tube 6, it moves with thetube 6 because thespring 13 pushes thesleeve 9 towards thepiston 2 as the valve handle 25 is moved toward the housing 1 when the tool is switched from closed center to open center as will be described. However, thesleeve valve 9 is not rotationally constrained with respect to theoil tube 6. - Operation of the
tool 100 in the CC mode will be described in relation to FIGS. 1 and 2. In FIG. 1, thetool 100 is in the neutral position, with thepiston 2 in the fully retracted position. Pressurized fluid is introduced into theinlet port 16, and thespool shaft 14 a of thevalve spool 14, with thetrigger 20 in the non-actuated position, channels the fluid from theinlet port 16 to thecentral port 29. Thecentral port 29 delivers the fluid to theoil tube 6. Since theholes 12 in the oil tube are not aligned with theholes 9 a in thesleeve valve 9, the fluid continues along theoil tube 6 until it reaches thebore 7, and passes throughhole 8 and into the retractchamber 3. Thepiston 2 is maintained in the fully retracted position based on application of the fluid in the retractchamber 3 on thepiston 2. Further, fluid from thedrive chamber 4 is exhausted to theoutlet port 15. Fluid is exhausted by passing from thedrive chamber 4, through a space S (best seen in FIG. 2) between an outside surface of thesleeve valve 9 and the inside surface of theselector sleeve 5, intochamber 19, through thecross port 31 and out theoutlet port 15. Theholes 9 a insleeve valve 9 are not aligned with thehole 12 in theoil tube 6, so there can be no fluid from flowing from the space S to theoil tube 6. - When the
trigger 20 is activated to perform an operation, as shown in FIG. 2, the valve spool 14 (via thespool shaft 14 a) directs pressurized fluid from theinlet port 16 to thecross port 31. Thecross port 31 communicates with thechamber 19, and the fluid continues past the space S between theselector sleeve 5 and thesleeve valve 9 and into thedrive chamber 4. Again, thesleeve valve 9 prevents the pressurized fluid from flowing into thehole 12 inoil tube 6. The pressurized fluid inchamber 4 moves thepiston 2. Thereciprocating ram 18 therefore extends outside the end of the housing 1. Fluid in the retractchamber 3 is exhausted throughhole 8 inram 18, theoil tube 6,central port 29 andoutlet port 15. Once thetrigger 20 is released, upon completion of the operation, thevalve spool 14 directs fluid as shown in FIG. 1, and the piston is returned to the fully retracted position. In this position, thepiston 2 does not contact theextension 45 of thevalve sleeve 9 since themode selector sleeve 5 is positioned in the CC position, e.g., it is spaced from the end of the housing 1. Thevalve sleeve 9 stays in the same position in FIGS. 1 and 2, in which theholes 12 of theoil tube 6 are covered by thevalve sleeve 9, i.e., theholes - In FIGS. 3 and 4, the
selector sleeve 5 has been rotated such that threaded engagement thereof with the interior surface of housing 1 causes theflange 47 ofselector 5 to approach and/or abut against anend 48 of the cylinder 1. Thus, theselector sleeve 5 has moved axially toward thepiston 2, as compared to the position of themode selector sleeve 5 in FIGS. 1 and 2. However, as shown in FIG. 3, thesleeve valve 9 does not move axially the same amount as theselector sleeve 5 because theextension 45 of thesleeve valve 9 abuts against thepiston 2, compressing thespring 13 in the process. Therefore, in FIG. 3, thepassages 12 of theoil tube 6 are aligned with theholes 9 a in thesleeve valve 9. Thespring 13 assumes a more compressed condition, as compared to the condition of thespring 13 shown in FIGS. 1, 2 and 4, and a shoulder of thesleeve valve 9 has become disengaged from the retainingring 27. - In the neutral position shown in FIG. 3, fluid is introduced into the
inlet port 16, and thevalve shaft 14 a of thevalve spool 14 directs the fluid into thecentral port 29, which communicates with theoil tube 6. Theoil tube 6 provides the fluid to the retractchamber 3 via theholes 8. Because theholes 9 a in thesleeve valve 9 are aligned with theholes 12 in theoil tube 6, any pressurized fluid in excess of an amount sufficient to move the piston to the retracted position passes through thepassages 12 in theoil tube 6 and theholes 9 a on thesleeve valve 9. Theball valves 10 allow the pressurized fluid to pass from the oil tube into the space S, and through thecavity 19, crossport 31 andoutlet port 15. Theball valves 10 do not allow passage of fluid in the reverse direction, i.e., from the space S to theoil tube 6. - When the
trigger 20 is activated as shown in FIG. 4, thevalve shaft 14 a of thevalve spool 14 channels fluid as shown in FIG. 2, to cause movement of thepiston 2. That is, fluid is delivered from theinlet port 16 to thecross port 31,chamber 19, space S and thedrive chamber 4. As thepiston 2 moves into the retractchamber 3, theextension 45 of thesleeve valve 9 extends into thedrive chamber 4 under the bias ofspring 13 until theshoulder 33 of thesleeve valve 9 abuts against the retainingring 27. In this condition, thesleeve valve 9 axially slides on theoil tube 6 such that theholes 12 of the oil tube no longer align with theholes 9 a of thesleeve valve 9. Also, theball valves 10 do not allow fluid to pass from the space S into theholes 9 a of thesleeve valve 9. - When the
trigger 20 is released, thevalve shaft 14 a of thespool 14 redirects fluid, as shown in FIG. 3. As thepiston 2 returns to the fully retracted position, thepiston 2 engages theextension 45 of thesleeve valve 9. At that point, thepiston 2 causes thesleeve valve 9 to slide with respect to theoil tube 6 against the bias of thespring 13, until theholes 12 of theoil tube 6 align with theholes 9 a of thesleeve valve 9, i.e., when the piston assumes the fully retracted position, as shown in FIG. 3. - Preferred embodiments of the present invention have been described with respect to the attached drawings, which are exemplary only and not limiting. Modifications, alterations, and other combinations of elements will occur to those of ordinary skill in the art without departing from the spirit or scope of the preferred embodiments described herein.
Claims (30)
Priority Applications (1)
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US09/858,905 US6490962B1 (en) | 2001-05-17 | 2001-05-17 | Hydraulic tool with an OC/CC selector |
Applications Claiming Priority (1)
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US09/858,905 US6490962B1 (en) | 2001-05-17 | 2001-05-17 | Hydraulic tool with an OC/CC selector |
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US20020170423A1 true US20020170423A1 (en) | 2002-11-21 |
US6490962B1 US6490962B1 (en) | 2002-12-10 |
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CN112211866A (en) * | 2020-09-17 | 2021-01-12 | 中冶宝钢技术服务有限公司 | Big arm control loop |
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US8267004B2 (en) * | 2009-05-20 | 2012-09-18 | Lifetime Enterprises, Llc | Adaptable hydraulic control system |
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US9205541B2 (en) | 2012-06-25 | 2015-12-08 | Hubbell Incorporated | Bucket truck intensifier |
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US11878402B2 (en) * | 2019-03-18 | 2024-01-23 | Milwaukee Electric Tool Corporation | Hydraulic power tool |
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DE4311191C2 (en) * | 1993-04-05 | 1995-02-02 | Deere & Co | Hydraulic system for supplying open or closed hydraulic functions |
US5442992A (en) | 1993-08-20 | 1995-08-22 | Greenlee Textron Inc. | Hydraulic control apparatus with selectively operated check valve assembly |
US5778755A (en) | 1996-03-01 | 1998-07-14 | Greenlee Textron Inc. | Control valve having a sensor switchable between an open and a closed condition |
-
2001
- 2001-05-17 US US09/858,905 patent/US6490962B1/en not_active Expired - Lifetime
Cited By (4)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
WO2015164226A1 (en) * | 2014-04-23 | 2015-10-29 | Ridge Tool Company | Hydraulic press tool |
US10010066B2 (en) | 2014-04-23 | 2018-07-03 | Ridge Tool Company | Hydraulic press tool |
GB2567839A (en) * | 2017-10-25 | 2019-05-01 | Hands Free Bolting Ltd | Remote hydraulic control apparatus |
CN112211866A (en) * | 2020-09-17 | 2021-01-12 | 中冶宝钢技术服务有限公司 | Big arm control loop |
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