EP3231765A1 - Système hydraulique intégré - Google Patents

Système hydraulique intégré Download PDF

Info

Publication number
EP3231765A1
EP3231765A1 EP16199011.4A EP16199011A EP3231765A1 EP 3231765 A1 EP3231765 A1 EP 3231765A1 EP 16199011 A EP16199011 A EP 16199011A EP 3231765 A1 EP3231765 A1 EP 3231765A1
Authority
EP
European Patent Office
Prior art keywords
valve
integral
hydraulic
hydraulic system
lifting
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.)
Withdrawn
Application number
EP16199011.4A
Other languages
German (de)
English (en)
Inventor
Xu Linjie
Liu Shunli
Lin Zuqian
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Ep Equipment Co Ltd
Original Assignee
Ep Equipment Co Ltd
Priority date (The priority date 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 date listed.)
Filing date
Publication date
Priority claimed from CN201610239511.8A external-priority patent/CN105883664A/zh
Application filed by Ep Equipment Co Ltd filed Critical Ep Equipment Co Ltd
Publication of EP3231765A1 publication Critical patent/EP3231765A1/fr
Withdrawn legal-status Critical Current

Links

Images

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
    • B66F9/20—Means for actuating or controlling masts, platforms, or forks
    • B66F9/22—Hydraulic devices or systems

Definitions

  • the invention relates to lifting mechanisms for use in lifting equipment, such as a pallet truck, and in particular to an integral hydraulic system that combines a hydraulic power unit, hydraulic control unit and hydraulic action unit into one complete unit.
  • Hydraulic systems for lifting equipment usually include a power unit, a control unit and an action unit. These components are an important part of a pallet truck, and the hydraulic system's function and cost are directly related to the cost, market prospects and promotion of the entire pallet truck. This is especially true as more modem pallet trucks have become lighter and less expensive, making the cost and volume or space occupied by the hydraulic system very important.
  • pallet truck lifting systems generally are of two kinds: manual and electrical.
  • Manual hydraulic systems include a pump that is easier and cheaper to make, but requires pumping by an operator, and therefore, more labor during use of the system.
  • Manual hydraulic systems also have limited lifting capacity, which together with the pumping required, affects the efficiency of using the pallet truck.
  • the hydraulic systems in electric pallet trucks tend to have components that are located separately from each other, such as an electric motor as a power unit, a valve body that serves as a hydraulic control unit, and a lift cylinder that serves as a hydraulic action unit, with a reservoir, a pump, the valve body and the lift cylinder fluidly connected to each other by a variety of conduits and/or houses. The extra components add cost and require more volume for the operable system.
  • the subject matter of this invention provides advantages over the structures of typical prior art hydraulic systems used in lifting equipment, such as pallet trucks.
  • the present invention provides an example integral hydraulic system having a valve board, a lift cylinder and a reservoir to provide an integral valve body, which advantageously can be directly connected to an electric motor and a hydraulic gear pump, so as to achieve a single unit.
  • This improved configuration permits a reduction in cost, volume and potential fluid leakage for pallet trucks. Indeed, this configuration is able to provide a pallet truck having a compact, integral hydraulic system that has significant lifting capacity, enhanced reliability and improves operator efficiency.
  • the invention provides an integral hydraulic system, including a valve board, a lift cylinder and a reservoir connected into one integral valve body, wherein the integral valve body is further connected to an electric motor and a hydraulic gear pump, so as to form a complete power unit that includes valves utilized in the different functions that control a hydraulic fluid circuit in the lifting and lowering of a plunger rod of the lift cylinder.
  • the invention provides an integral hydraulic system that has a lowering valve that includes an unloading spring, an O-ring, a firing pin, and a firing pin pedestal that are installed inside the valve board.
  • the invention provides an integral hydraulic system that has a lifting valve that includes a valve orifice, a screw, a valve needle, a valve spring, and a ball that provide a one-way valve biased by the valve spring.
  • the invention provides an integral hydraulic system that has a relief valve that includes a screw, an adjusting screw, a spring, a ball pedestal, and a ball that are installed inside the valve board.
  • the present invention presents alternatives to prior art manual and electric hydraulic systems for lifting equipment, such as pallet trucks and provides advantageous features by bringing together previously separated components to greatly improve the convenience, utility and efficiency in operating such lifting equipment.
  • the invention provides solutions to the technical problem presented by existing manually and electrically operated hydraulic lifting systems, such as are used in pallet trucks.
  • the invention teaches an integral hydraulic system having a valve board, a lift cylinder and a reservoir combined within an integral valve body, which advantageously is further directly connected to an electric motor and a hydraulic gear pump, so as to achieve a self-contained, full power unit.
  • an example of such an integral hydraulic system is disclosed herein, such as may be used in pallet trucks, or other lifting equipment.
  • the system is described further herein in reference to a preferred embodiment shown in the accompanying drawing FIGS. 1-3 . It will be appreciated, however, that the invention may be constructed and configured in various ways and is not limited to the specific example in the form of the preferred embodiment shown and described herein.
  • the present invention provides an integral hydraulic system that combines the space saving advantages of a manual pump system and the lower labor, higher lifting capacity of an electric pump system. But to do so, the example integral hydraulic system utilizes an entirely new way to connect the components, which also reduces the potential for leakage, while reduces the number of components.
  • the integral hydraulic system includes an electric motor, a hydraulic gear pump and a power source, together with an integral valve body that includes a valve board, a lift cylinder and a reservoir, with all of the components connected together within a relatively small volume.
  • a motor 3 and a hydraulic gear pump 19 are connected to a valve body 21 by screws 2, 20, respectively, making up a single, but complete power unit of an integral hydraulic system 22.
  • the valve body 21 includes a reservoir 23, a valve board 24 and lift cylinder 18, the combination of which reduces the volume of the entire system, while internalizing the fluid connections to avoid leakage and pollution.
  • a cross section of the valve board 24 is shown in FIG. 3 .
  • hydraulic fluid flows from the hydraulic gear pump 19 of the integral hydraulic system 22, to a lifting valve 25 that is constructed within the valve board 24 and includes a valve end 13, a valve seat screw 14, a valve needle 15, a first spring 16, and a first ball 17, such as a steel ball, all of which are combined essentially into a one-way valve biased by the first spring 16 toward a closed position, shown in FIG. 3 .
  • the flow of hydraulic fluid from the hydraulic gear pump 19 overcomes the force of the first spring 16 and moves the first valve needle 15 to an open position, to permit the hydraulic fluid to enter into the lift cylinder 18, so as to push upward the plunger rod 1 of the lift cylinder 18, realizing the desired lifting function.
  • the fluid pressure in the lift cylinder 18 below the plunger rod 1 makes the first ball 17 seal the opposed passage within the valve board 24 that is associated with a lowering valve 26, and the first spring 16 and increased hydraulic pressure now in the cylinder 18 pushes the valve needle 15 to engage the valve seat screw 14, so as to lock and retain the lifting pressure within the valve board 24 of the valve body 21.
  • the lowering valve 26 includes an unloading second spring 4, an O-ring 5, a firing pin 6, and firing pin pedestal 7, all combined to have the firing pin 6 biased by the second spring 4 toward a withdrawn position, shown in FIG. 3 .
  • the firing pin pedestal 7 and firing pin 6 are utilized to push the first ball 17 back toward the lifting valve 25, so as to push the valve needle 15 to an open position, permitting the reversal of fluid flow to the reservoir 23 and pump 19 as the plunger rod 1 descends within the lift cylinder 18.
  • the unloading second spring 4 will force the firing pin 6 to reset with the firing pin pedestal 7 by moving toward the withdrawn position.
  • a relief valve 27 will protect the system by relieving the excess pressure.
  • the hydraulic fluid will force the second ball 12, such as a steel ball, and a ball pedestal 11 to an open position by overcoming the force of a third spring 10, so as to open the relief valve 27 to a passage 28 that provides pressure relief.
  • the maximum rated pressure for the system can be adjusted by an adjusting screw 9, which controls the biasing pressure applied by the third spring 10, and a sealing screw 8 is used to seal the relief valve 27.
  • valve board 24, a lift cylinder 18 and a reservoir 23 make up one integral valve body 21.
  • an electric motor 3 and a hydraulic gear pump 19 are connected to the valve body 21, such as by the two screws 2, 20, respectively, or other suitable fasteners.
  • the valves 25, 26, 27 within the valve board 24 of the integral hydraulic system 22 provide hydraulic fluid flow for the all of the different required functions.
  • these valves included the lifting valve 25, which is biased to be a one-way valve used when raising the plunger rod 1 of the lift cylinder 18 for lifting, a manual lowering valve 26 for reversing the fluid flow for lowering the plunger rod 1, and a relief valve 27 that protects the entire system from damage that may be caused by excessive pressures.
  • the lift cylinder 18 of the valve body 21 uses the plunger rod 1 to realize the lifting and lowering.
  • hydraulic fluid enters the lift cylinder 18 via the lifting one-way valve 25, and pushes the plunger rod 1 to provide lifting.
  • the lowering valve 26 utilizes the firing pin 6 to push to an open position the valve needle 15 of the lifting valve 25, permitting return of the hydraulic fluid and lowering of the plunger rod 1.
  • the firing pin 6 and valve needle 15 will be reset by the second spring 4 and first spring 16, respectively.
  • the relief valve 27 will protect the entire integral hydraulic system 22 when the lift cylinder 18 is subjected to excess weight applied to the plunger rod 1, and the pressure at which the relief valve is activated can be adjusted by use of the adjusting screw 9 that controls the length of the space the third spring 10 occupies behind the ball pedestal 11, which pushes the second ball 12.
  • the valve board 24, lift cylinder 18 and reservoir 23 make up one integral valve body 21 that is connected directly to the electric motor 3 and hydraulic gear pump 19, such that no extra externally extending conduits or tubes are used in the fluid connections of the components.
  • the power unit of the integral hydraulic system 22 is of significantly smaller volume, complexity and weight, providing for a more compact and reliable hydraulic system.
  • the valve body 24 uses the valve needle 15 to realize the sealing of the fluid passages, and the first spring 16 provides a biasing force.
  • These components are included in the one-way lifting valve assembly 25 with simple and reliable operation, when an operator decides to energize the hydraulic gear pump 19 to send pressurized fluid to the valve body 24 to affect lifting, which overcomes the biasing force of the first spring 16.
  • the hydraulic fluid will be drawn from the reservoir 23 and pumped by the hydraulic gear pump 19 to the one-way lifting valve 25, and will overcome the biasing force of valve spring 16, move the valve needle 15 to an open position and enter the lift cylinder 18.
  • the hydraulic fluid then will push the plunger rod 1 upward to realize the desired lifting.
  • the firing pin 6 will push the first ball 17, so as to push the valve needle 15 to an open position and permit return fluid flow toward the hydraulic gear pump 19 and reservoir 23.
  • the third spring 10 forces the ball pedestal 11, which pushes the second ball 12 to a closed position.
  • the adjusting screw 9 may be used to adjust the maximum rated pressure permitted before the relief valve 27 will be triggered within the valve board 24 of the integral hydraulic system 22.
  • the operator When an operator wishes to lower the plunger rod 1, the operator will actuate a knob on a device, such as on a pallet truck operating handle, so as to move an activation plate that pushes the firing pin 6, so as to cause the firing pin 6 to push the first ball 17 to an open position, which in turn pushes the valve needle 15 to realize the reversing of the flow of hydraulic fluid.
  • a knob on a device such as on a pallet truck operating handle
  • the integral hydraulic system utilizes a valve board, a lift cylinder and a reservoir to provide an integral valve body, which advantageously can be connected directly to an electric motor and a hydraulic gear pump to achieve the full power unit.
  • This space-efficient assembly increases lifting capacity over that of a typical manual hydraulic system, while reducing operator effort.
  • the integral hydraulic system also reduces potential leakage and environmental impact, while improving operator efficiency.

Landscapes

  • Engineering & Computer Science (AREA)
  • Transportation (AREA)
  • Structural Engineering (AREA)
  • Chemical & Material Sciences (AREA)
  • Combustion & Propulsion (AREA)
  • Civil Engineering (AREA)
  • Life Sciences & Earth Sciences (AREA)
  • Geology (AREA)
  • Mechanical Engineering (AREA)
  • Fluid-Pressure Circuits (AREA)
EP16199011.4A 2016-04-15 2016-11-16 Système hydraulique intégré Withdrawn EP3231765A1 (fr)

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
CN201610239511.8A CN105883664A (zh) 2016-04-15 2016-04-15 一体式液压系统
US15/163,315 US20170298963A1 (en) 2016-04-15 2016-05-24 Integral Hydraulic System

Publications (1)

Publication Number Publication Date
EP3231765A1 true EP3231765A1 (fr) 2017-10-18

Family

ID=57354136

Family Applications (1)

Application Number Title Priority Date Filing Date
EP16199011.4A Withdrawn EP3231765A1 (fr) 2016-04-15 2016-11-16 Système hydraulique intégré

Country Status (1)

Country Link
EP (1) EP3231765A1 (fr)

Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US11401145B2 (en) 2019-08-23 2022-08-02 Hyster-Yale Group, Inc. Integrated drive and hydraulic actuator unit

Citations (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
IL55148A (en) * 1978-07-16 1981-02-27 Koor Metal Ltd Dual rate jack system for lift trucks
US20140124299A1 (en) * 2012-11-01 2014-05-08 Parker-Hannifin Corporation Electro-hydraulic actuator (eha) for pallet truck

Patent Citations (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
IL55148A (en) * 1978-07-16 1981-02-27 Koor Metal Ltd Dual rate jack system for lift trucks
US20140124299A1 (en) * 2012-11-01 2014-05-08 Parker-Hannifin Corporation Electro-hydraulic actuator (eha) for pallet truck

Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US11401145B2 (en) 2019-08-23 2022-08-02 Hyster-Yale Group, Inc. Integrated drive and hydraulic actuator unit

Similar Documents

Publication Publication Date Title
US20170298963A1 (en) Integral Hydraulic System
US3952516A (en) Hydraulic pressure amplifier
US4339942A (en) Hydraulically operated crimping tool
US20120006014A1 (en) Multi-speed hydraulic jack
US3515167A (en) Hydraulic and electrical power unit
MXPA03001446A (es) Valvula de liberacion de accion directa a varias presiones, con accionamiento a distancia.
US8459019B2 (en) System and method for pilot-operated high pressure valve
US3787147A (en) Two-stage air-hydraulic booster
EP3231765A1 (fr) Système hydraulique intégré
US7850248B2 (en) Hydraulic system
US6347786B1 (en) Hydraulic jack lifting mechanism
US7316177B2 (en) Hydraulic hand pump with locking device
US3824043A (en) Hydraulic pump and valve unit
CN203223377U (zh) 一种改进型液压齿轮泵
CN201722100U (zh) 一种气动液压千斤顶
CN109630372B (zh) 一种新型超高压先导型液压手动泵
CN201425044Y (zh) 一种自卸车用气控换向阀
CN110303076B (zh) 手动液压折弯装置
CN209761647U (zh) 一种新型超高压先导型液压手动泵
CN102102718A (zh) 塔机制动动力单元
US4359205A (en) Hydraulically operated lifting apparatus and pump therefor
JP2858168B2 (ja) リフト運搬台車等の昇降用油圧装置
US3410087A (en) Hydraulic jack
CN106194641B (zh) 一种驾驶室液压举升装置
CN212202661U (zh) 带断电复位功能的电液作动器

Legal Events

Date Code Title Description
PUAI Public reference made under article 153(3) epc to a published international application that has entered the european phase

Free format text: ORIGINAL CODE: 0009012

AK Designated contracting states

Kind code of ref document: A1

Designated state(s): AL AT BE BG CH CY CZ DE DK EE ES FI FR GB GR HR HU IE IS IT LI LT LU LV MC MK MT NL NO PL PT RO RS SE SI SK SM TR

AX Request for extension of the european patent

Extension state: BA ME

STAA Information on the status of an ep patent application or granted ep patent

Free format text: STATUS: THE APPLICATION IS DEEMED TO BE WITHDRAWN

18D Application deemed to be withdrawn

Effective date: 20180419