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
  • B66F9/00—Devices for lifting or lowering bulky or heavy goods for loading or unloading purposes
  • B66F9/06—Devices for lifting or lowering bulky or heavy goods for loading or unloading purposes movable, with their loads, on wheels or the like, e.g. fork-lift trucks
  • B66F9/075—Constructional features or details
  • B66F9/12—Platforms; Forks; Other load supporting or gripping members
  • B66F9/14—Platforms; Forks; Other load supporting or gripping members laterally movable, e.g. swingable, for slewing or transverse movements
  • B66F9/142—Movements of forks either individually or relative to each other
  • B66F9/143—Movements of forks relative to each other - symmetric
• • 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
  • B66F9/00—Devices for lifting or lowering bulky or heavy goods for loading or unloading purposes
  • B66F9/06—Devices for lifting or lowering bulky or heavy goods for loading or unloading purposes movable, with their loads, on wheels or the like, e.g. fork-lift trucks
  • B66F9/075—Constructional features or details
  • B66F9/12—Platforms; Forks; Other load supporting or gripping members
  • B66F9/14—Platforms; Forks; Other load supporting or gripping members laterally movable, e.g. swingable, for slewing or transverse movements
  • B66F9/147—Whole unit including fork support moves relative to mast
  • B66F9/148—Whole unit including fork support moves sideways
• • 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
  • B66F9/00—Devices for lifting or lowering bulky or heavy goods for loading or unloading purposes
  • B66F9/06—Devices for lifting or lowering bulky or heavy goods for loading or unloading purposes movable, with their loads, on wheels or the like, e.g. fork-lift trucks
  • B66F9/075—Constructional features or details
  • B66F9/20—Means for actuating or controlling masts, platforms, or forks
  • B66F9/22—Hydraulic devices or systems
• • 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
  • F15B11/16—Servomotor systems without provision for follow-up action; Circuits therefor with two or more servomotors
  • F15B11/20—Servomotor systems without provision for follow-up action; Circuits therefor with two or more servomotors controlling several interacting or sequentially-operating members
• • 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
  • F15B13/06—Fluid distribution or supply devices characterised by their adaptation to the control of servomotors for use with two or more servomotors
  • F15B13/07—Fluid distribution or supply devices characterised by their adaptation to the control of servomotors for use with two or more servomotors in distinct sequence
• • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
  • Y10—TECHNICAL SUBJECTS COVERED BY FORMER USPC
  • Y10T—TECHNICAL SUBJECTS COVERED BY FORMER US CLASSIFICATION
  • Y10T137/00—Fluid handling
  • Y10T137/2496—Self-proportioning or correlating systems
  • Y10T137/2544—Supply and exhaust type
  • Y10T137/2554—Reversing or 4-way valve systems
• • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
  • Y10—TECHNICAL SUBJECTS COVERED BY FORMER USPC
  • Y10T—TECHNICAL SUBJECTS COVERED BY FORMER US CLASSIFICATION
  • Y10T137/00—Fluid handling
  • Y10T137/8593—Systems
  • Y10T137/86493—Multi-way valve unit
  • Y10T137/86574—Supply and exhaust
  • Y10T137/8667—Reciprocating valve
• • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
  • Y10—TECHNICAL SUBJECTS COVERED BY FORMER USPC
  • Y10T—TECHNICAL SUBJECTS COVERED BY FORMER US CLASSIFICATION
  • Y10T137/00—Fluid handling
  • Y10T137/8593—Systems
  • Y10T137/86493—Multi-way valve unit
  • Y10T137/86574—Supply and exhaust
  • Y10T137/8667—Reciprocating valve
  • Y10T137/86694—Piston valve
  • Y10T137/8671—With annular passage [e.g., spool]

Definitions

• the invention is related to hydraulic systems, and in particular, to a multi-function hydraulic valve assembly.
• a piece of machinery such as a hoist or a truck, may require several hydraulic operators to move the load in different ways.
• the various hydraulic operators are each controlled by a lever located in the cab of the machine or vehicle.
• lift trucks are vehicles which are used to pick up and move loads from place to place.
• a conventional lift truck includes a carriage which supports a pair of forks. The forks are maneuvered into place by the lift truck operator and are used to pick up the load.
• the carriage rides vertically in a mast, which also supports the carriage. In addition the mast may be tilted backward to facilitate stabilizing the load on the forks.
• Two separate hydraulic operators are used to move the carriage vertically and to tilt the mast.
• a side shift assembly which facilitates aligning the spaced pair of forks with the load.
• side shifting is used to describe the concept of shifting the forks as a spaced pair either left or right of the vehicle center line. This function provides the operator with a greater margin for error when aligning the vehicle with the load.
• a hydraulic operator such as a piston/cylinder arrangement is typically used by the side shifting assembly to move a frame to which the forks are secured.
• Another attachment to enhance the capability of a lift truck is a fork positioning assembly.
• the term fork positioning is used to describe the concept of changing the relative spacing between the forks to accommodate loads of different widths. Again, a hydraulic operator, such as a piston/cylinder arrangement is used in the fork positioning assembly to move the forks.
• a cab of a conventional lift truck provides three levers to operate three hydraulic operators. Accordingly, if a user requires four hydraulic operators, such as, for example, by installing a fork positioning attachment, an additional lever must be installed to operate the fork positioning attachment.
• prior art systems permit operation of two separate hydraulic operators with a single lever on a lift truck. These systems utilize an electrical circuit to toggle between the two hydraulic operators. Prior to moving the lever which actuates the hydraulic system, the user would activate the electrical switch to select the appropriate hydraulic operator. This system adds expense and complexity to the design of the lift truck. In addition, electrical cables must be provided and extended over the lift truck mast. [0008] Accordingly, there is a need for a hydraulic valve assembly which permits selectable hydraulic operation of more than one hydraulic operator with a single lever.
• a hydraulic valve assembly for delivering hydraulic fluid from a supply of hydraulic fluid to one of a first hydraulic operator and a second hydraulic operator.
• the assembly comprises:
• a valve block defining: i) a first supply port adapted for fluid communication with said supply; ii) a second supply port adapted for fluid communication with said supply; iii) a first operator port adapted for fluid communication with said first hydraulic operator; iv) a second operator port adapted for fluid communication with said second hydraulic operator; v) a third operator port adapted for fluid communication with said first hydraulic operator; vi) a fourth operator port adapted for fluid communication with said second hydraulic operator; vii) a first chamber, said first chamber being in fluid communication with said first supply port, said first operator port, and said second operator port; viii) a second chamber, said second chamber being in fluid communication with said second supply port, said third operator port and said fourth operator port;
• a hydraulic valve assembly for delivering hydraulic fluid from a supply of hydraulic fluid to one of a first hydraulic operator and a second hydraulic operator.
• the assembly comprises: [0013] a) a valve block defining: i) a supply port adapted for fluid communication with said supply; ii) a first operator port adapted for fluid communication with said first hydraulic operator; iii) a second operator port adapted for fluid communication with said second hydraulic operator; iv) a chamber, said chamber being in fluid communication with said supply port, said first operator port, and said second operator port;
• a selection valve located in said chamber, said selection valve operable between a first position when said hydraulic fluid is at a first pressure and a second position when said hydraulic fluid is at said second pressure, where in said first position, said selection valve permits fluid communication between said supply port and said first operator port, where in said second position, said first selection valve permits fluid communication between said supply port and said second operator port; wherein said first pressure is lower than said second pressure.
• Figure 1 is a schematic of a hydraulic system for a lift truck
• Figure 2 is a perspective view of a valve assembly according to a preferred embodiment of the present invention.
• Figure 3 is a cross-sectional view of a valve block for the preferred embodiment of Figure 2;
• Figure 4 is a perspective view of a selection valve for the preferred embodiment of Figure 2;
• Figure 5A is a cross-sectional view of the preferred embodiment of Figure 2in a first position showing fluid flow in one direction;
• Figure 5B is a cross-sectional view of the preferred embodiment in the first position as shown in Figure 5A, but showing fluid flow in an opposite direction;
• Figure 5C is a cross-sectional view of the preferred embodiment of Figure 2 in a second position showing fluid flow in one direction;
• Figure 5D is a cross-sectional view of the preferred embodiment in the second position, as shown in Figure 5C, but showing fluid flow in the opposite direction;
• Figure 6 is a schematic view showing the preferred embodiment of Figure 2 connected to a side shifter and fork positioner.
• FIG. 1 shows a hydraulic system for a lift truck connected to a valve assembly 10 according to a preferred embodiment of the present invention.
• the valve assembly 10 is connected to a control panel 11 by a first hydraulic supply line 12 and a second hydraulic supply line 14.
• the control panel 11 is connected to a hydraulic fluid tank 16 by a tank supply line 18 and a tank return line 20.
• a pump (not shown) is connected to the tank supply line 18 to provide the hydraulic fluid under pressure.
• the control panel 11 includes a hydraulic circuit 26 to interchangeably connect the tank supply and return lines 18, 20 to the first and second hydraulic supply lines 12 and 14.
• the circuit 26 is operated in a conventional manner and will not be further described.
• the circuit 26 is hydraulically connected to three corresponding levers in the lift truck cab. Other similar circuits may be used to control other vehicle functions such as mast tilting, carriage raising, and the like. For convenience, only the lever 28 for operating the particular circuit 26 is shown. It will be understood by those skilled in the art that other types of actuators may be provided.
• the valve assembly includes a valve block 30, which preferably has a box-like shape.
• a first supply port 32 and a second supply port 34 are provided in the valve block 30.
• the first and second supply ports 32, 34 communicate with first and second hydraulic supply lines 12, 14 (shown in Figure 1), respectively.
• the supply ports 32, 34 are located on the same face of the block 30.
• An orifice valve 35 (shown in Figures 5A-5D) is preferably provided between the supply ports 32 and 34. The function of this orifice valve is discussed below. Preferably, the diameter of the orifice valve may be about 0.043 inches. [0029] Referring now to Figure 3, a first chamber 36 and a second chamber 38 are provided in the valve block 30. The first and second chambers 36, 38 communicate with first and second supply ports 32, 34 via first and second block channels 40 and 42.
• valve block 30 four operator ports are provided in the valve block 30.
• a first operator port 44 and a second operator port 46 are provided on one face of the block 30, and a third operator port 48 and a fourth operator port 50 are provided on the opposite face of the block 30.
• the first and second operator ports 44, 46 communicate with the first chamber 36.
• the third and fourth operator ports 48, 50 communicate with the second chamber 38.
• the first hydraulic operator may be, for example, a fork positioning cylinder.
• the second and fourth operator ports 46, 50 are connected to corresponding ports (not shown) of a second hydraulic operator 82.
• the second hydraulic operator may be, for example, a side shifting cylinder.
• a pilot channel 52 is provided in the valve block 30.
• the pilot channel 52 communicates with first and second chambers 36, 38.
• the pilot channel 52 also communicates with first and second block channels 40, 42, all three meeting at an intersection 54.
• a bi-directional valve 56 is located in the intersection 54.
• the bi-directional valve is a conventional ball and shuttle valve.
• the bi-directional valve alternatively connects pilot channel 52 with block channel 40 or block channel 42.
• a first conventional selection valve 60 is located in the first chamber 36 and a second conventional selection valve 61 is located in the second chamber 38.
• the selection valves 60, 61 are identical.
• the first selection valve 60 includes a generally cylindrical valve housing 62 mounted in the first chamber 36.
• the cylindrical valve housing 62 has an open end proximate to the pilot channel 52, and defines an internal valve chamber 64.
• the cylindrical valve housing 62 also includes a plurality of radially directed circumferentially arranged openings 65 for communicating with the first chamber 36.
• a moving valve body 66 is located within the valve chamber 64 of valve housing 62.
• the valve body 66 has a pressure surface 68 adjacent the open end of the valve housing 62.
• the valve body 66 has a narrower portion which defines an annular space 69.
• the radially directed openings 65 communicate with the annular space 69 between the valve body 66 and the valve housing 62.
• the valve body 66 is connected to a spring 74 located in a closed end of the cylindrical valve housing 62. Valve body 66 may be moved relative to valve housing 62 by collapsing the spring 74.
• the spring 74 biases the valve body 66 to the position shown in Figures 5A and 5B.
• the spring resistance is configured such that a pressure of 315 PSI or greater applied to pressure surface 68 is required to collapse the spring 74 so that the valve body 66 may move to the position shown in Figures 5C and 5D.
• a number of external O-rings 70, 72 are provided to seal portions of the first selection valve 60 against portions of the wall of the first chamber 36.
• Internal O-rings (not shown) are also provided to seal the upper and lower ends of the annular space 69 from the remainder of the valve chamber 64 to prevent bleeding of fluid between the valve body 66 and valve housing 62.
• the operation of the present invention will be described in conjunction with a conventional hydraulically-operated fork positioner 80 and side shifter 82 for a lift truck.
• the first hydraulic operator will be the fork positioner
• the second hydraulic operator will be the side shifter.
• the present invention may be operated with any two hydraulic operators requiring different pressure, and is not confined to fork positioners and side shifters, or to hydraulic operators for lift trucks. The operators could be used for any desired function, such as rotating, tilting, clamping, or the like.
• the lift truck operator when the lift truck operator wishes to actuate the fork positioner in a first direction, such as to narrow the forks, the operator moves the lever 28 part-way in one direction.
• the circuit 26 is partially activated to supply hydraulic fluid from the hydraulic fluid tank 16 along tank supply line 18, through section 22, and then to the first hydraulic supply line 12. Because, the circuit 26 is only partly activated, the flow rate of hydraulic fluid in the first hydraulic supply line 12 is low, resulting in low pressure as explained below. Preferably, low pressure means pressure below 315 PSI.
• the hydraulic fluid enters the first supply port 32 and flows into first channel 40.
• the pressure of the fluid in first block channel 40 moves the bi-directional valve 56 into a position permitting fluid communication between first block channel 40 and pilot channel 52, while sealing off communication between second block channel 42 and the pilot channel 52.
• the pressure of the fluid in the pilot channel 52 acts on the pressure surface 68 of each of the selection valves 60, 61. Because the pressure is below 315 PSI, neither of the valve bodies 66 of the selection valves 60, 61 move. Accordingly, the annular channels of selection valves 60 and 61 remain aligned with first operator port 44 and third operator port 48, respectively.
• the supply fluid in first block channel 40 also enters the annular space 69 through the radially directed openings 65 in the cylindrical housing 62 of the first selection valve 60. The fluid exits from the annular space 69 of first selection valve 60 through additional radially directed openings 65 and enters first operator port 44. The fluid is prevented from entering second operator port 46 by O-ring 70 and the internal O-rings of the selection valve 60.
• the hydraulic fluid travels to the fork positioner 80 by line 84 connected to first operator port 44.
• hydraulic fluid also leaves the fork positioner 80 and enters third operator port 48 via line 86.
• the fluid is routed to second block channel 42 through the second selection valve 61 , in a similar but reverse manner as described for first selection valve 60.
• the fluid exits the valve assembly 10 at second supply port 34 along second supply line 14.
• the hydraulic fluid enters the valve block 30 via the second supply port 34 and into the second block channel 42.
• the bi-directional valve 56 is moved in the other direction such that it is now the second block channel 42 which communicates with the pilot channel 52. Because it is low pressure fluid, neither of the valve bodies 66 of selection valves 60 and 61 move from the position shown in Figure 2B. However, the hydraulic fluid flows through second selection valve 61 in the same manner as described for the first selection valve 60.
• the hydraulic fluid flows out of third operator port 48 and into line 86 to the fork positioner 80. This causes the fork positioner to operate in the opposite direction.
• Hydraulic fluid flowing out of fork positioner 80 into line 84 enters the valve assembly 10 at first operator port 44.
• the returning fluid is directed into first channel 40 by the first selection valve 60, as described above.
• the fluid exits at first supply port 32 and is returned to the tank return line 20 via first supply line 12.
• moving the lever 28 either way causes the fork positioner 80 to move in either direction (i.e. narrowing or widening the fork spacing).
• the hydraulic fluid enters the first chamber 36 along the same path as described for the narrowing function of the fork positioner.
• the now high pressure fluid passes to the pilot channel 52 and acts against surface 68 of each of the valve bodies 66 of the selection valves 60 and 61. Because the pressure in the pilot channel 52 acting against pressure surface 68 of each valve body 66 is greater than the resistance of the respective springs 74, the valve body 66 of each selection valve moves against the spring 74. This moves the valve bodies 66 to the positions shown in Figures 5C and 5D, and thereby permits fluid in first block channel 40 to flow through annular space 69 and into second operator port 46. O-ring 72 prevents fluid communication with first operator port 44.
• hydraulic fluid flows to the side shifter 82 along line 88.
• Hydraulic fluid returns to fourth operator port 50 along line 90, then through selection valve 61.
• the fluid flows through the valve block 30 and out through the second supply port 34 in a manner analogous to the manner described above.
• the fluid is returned to the tank in the same manner as described for the narrowing function of the fork positioner.
• the hydraulic operators are able to achieve their required functions while operating at different pressures.
• One pressure is referred to herein as the lower pressure, while the other pressure is referred to as the higher pressure.
• Absolute values are, of course, widely variable. However, it is preferred that the two pressures differ by about 50 PSI.
• fork positioning can be successfully preformed using pressures of less than 250 PSI, while side shifting can be accomplished using pressures above 325 PSI.
• Other pressures and other pressure differentials can be used depending on the vehicle and the implements being controlled.
• the high pressure in the supply lines 12 and 14 is achieved by moving lever 28 quickly to the full open position in the desired direction.
• the orifice valve 35 may be provided to reduce any hammer effect which may be caused by sudden changes in direction of the fluid flow.
• the preferred embodiment of the invention described above is configured to provide selectable, two-way, hydraulically actuated movement. However, certain hydraulic operators may require only one way movement. The return movement of the hydraulic operator may be provided by some other source, such as a spring or gravity. For such hydraulic operators, the second supply port 34, second block channel 42, second selection valve 61 , bi-directional valve 56, and third and fourth operator ports 48, 50 may be omitted.

Landscapes

• Engineering & Computer Science (AREA)
• Transportation (AREA)
• Structural Engineering (AREA)
• Mechanical Engineering (AREA)
• Civil Engineering (AREA)
• Life Sciences & Earth Sciences (AREA)
• Geology (AREA)
• Fluid Mechanics (AREA)
• General Engineering & Computer Science (AREA)
• Physics & Mathematics (AREA)
• Combustion & Propulsion (AREA)
• Chemical & Material Sciences (AREA)
• Forklifts And Lifting Vehicles (AREA)
• Multiple-Way Valves (AREA)
• Mechanically-Actuated Valves (AREA)
• Valve Housings (AREA)
• Servomotors (AREA)
• Fluid-Pressure Circuits (AREA)

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• 2003
  • 2003-02-14 DE DE60329471T patent/DE60329471D1/de not_active Expired - Lifetime
  • 2003-02-14 EP EP20030701411 patent/EP1481168B1/fr not_active Expired - Lifetime
  • 2003-02-14 JP JP2003573302A patent/JP2005519244A/ja active Pending
  • 2003-02-14 AT AT03701411T patent/ATE444449T1/de not_active IP Right Cessation
  • 2003-02-14 CA CA 2476759 patent/CA2476759C/fr not_active Expired - Lifetime
  • 2003-02-14 AU AU2003203106A patent/AU2003203106A1/en not_active Abandoned
  • 2003-02-14 CN CNB038049597A patent/CN100404882C/zh not_active Expired - Lifetime

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