Pallet fork hydraulic system and forklift loader

Abstract

The invention belongs to the field of engineering machinery, and discloses a forklift loader and a fork hydraulic system.The fork hydraulic system comprises a first oil cylinder and a second oil cylinder, rod cavities between the first oil cylinder and the second oil cylinder are communicated with each other, a rodless cavity of the first oil cylinder is connected with a first sidesway working oil way, and a rodless cavity of the second oil cylinder is connected with a second sidesway working oil way. A rodless cavity of the second oil cylinder is connected with a second lateral displacement working oil way; and a multi-way valve to which the first side shift working oil path and the second side shift working oil path are hydraulically connected. The two oil cylinders can be driven to generate synchronous transverse movement on the opposite sides, and therefore synchronous lateral movement hydraulic driving is achieved. The distance between the fork knives of the pallet fork is adjusted in a non-manual mode, goods can be conveniently taken by the pallet fork, the left-right position adjustment of heavy goods loaded by the pallet fork on the pallet fork portal frame can be achieved, and the heavy goods can be conveniently and accurately stacked.

Description

TECHNICAL FIELD

[0001] The present application belongs to the field of engineering machinery, and in particular relates to a fork hydraulic system and a forklift truck. BACKGROUND

[0002] The forklift truck in a loaded state, i.e. after the fork is loaded, cannot move the heavy object on the fork left and right by manpower, which is extremely inconvenient for stacking. Therefore, the fork tines can only be manually moved by pure manpower in an unloaded or lightly loaded state, which is time-consuming and laborious. For a fork tine with a large weight, several people are needed to move it. Moreover, the fork tines need to be frequently moved back and forth between the cab and the fork position each time, which wastes operation time. SUMMARY

[0003] The purpose of the present application is to provide a fork hydraulic system and a forklift truck to realize synchronous left and right movement of fork tines.

[0004] To achieve the above purpose, the present application provides a fork hydraulic system in one aspect, which is applied to a forklift truck, and comprises: a first oil cylinder and a second oil cylinder, a rod cavity between the first oil cylinder and the second oil cylinder being in communication with each other, a rodless cavity of the first oil cylinder being connected with a first side movement working oil path, and a rodless cavity of the second oil cylinder being connected with a second side movement working oil path; a multi-way valve, the first side movement working oil path and the second side movement working oil path being hydraulically connected to the multi-way valve.

[0005] In some embodiments, the fork hydraulic system comprises: a folding working oil path hydraulically connected to the rod cavity of the first oil cylinder and the rod cavity of the second oil cylinder; an unfolding working oil path hydraulically connected to the rodless cavity of the first oil cylinder and the rodless cavity of the second oil cylinder; a reversing valve for connecting an implement group oil path of the multi-way valve to the first side movement working oil path, the second side movement working oil path, or alternatively to the folding working oil path and the unfolding working oil path.

[0006] In some embodiments, the fork hydraulic system comprises: an on-off control valve for controlling the cutoff or communication between the rodless cavity of the first oil cylinder and the rodless cavity of the second oil cylinder.

[0007] In some embodiments, the on-off control valve is a cartridge valve arranged in a connecting oil path between the unfolding working oil path and the second side movement working oil path.

[0008] In some embodiments, the fork hydraulic system comprises: The shuttle valve is hydraulically connected to the first side shift working oil path and the second side shift working oil path through two comparative oil ports respectively, and the oil outlet is hydraulically connected to the control oil port of the plug-in valve.

[0009] In some embodiments, the reversing valve is a two-position six-way electromagnetic reversing valve.

[0010] In some embodiments, the hydraulic valves in the first side shift working oil path, the second side shift working oil path, the closing working oil path and the opening working oil path are arranged on the forks of the forklift, and the reversing valve is arranged at the head of the arm frame of the forklift.

[0011] In some embodiments, the fork hydraulic system comprises: Quick-change joints, the first side shift working oil path, the second side shift working oil path, the closing working oil path and the opening working oil path are connected to the reversing valve through the quick-change joints respectively.

[0012] In some embodiments, the hydraulic valves in the first side shift working oil path and the second side shift working oil path each comprise a hydraulic lock, and the hydraulic valves in the closing working oil path and the opening working oil path each comprise a speed regulating valve, an overflow valve and a hydraulic lock.

[0013] In addition, the application also provides a forklift comprising the fork hydraulic system described above.

[0014] In the technical solution of the application, the rod cavities of the two oil cylinders are connected to each other, i.e., the two oil cylinders are connected in series, so that high-pressure oil can be introduced into the rodless cavities of the corresponding sides through the working oil paths according to the side shift direction, i.e., the two oil cylinders can be driven to produce synchronous lateral movement in the opposite direction, thereby realizing synchronous side shift hydraulic driving. In this way, the distance between the forks is adjusted by a non-manual method, which not only facilitates the adjustment of the forks to take objects when the forks are empty, but also can realize the left-right position adjustment of heavy objects on the fork gantry after the forks are loaded, thereby facilitating precise stacking of heavy objects.

[0015] Other features and advantages of the embodiments of the application will be described in detail in the following specific embodiments. BRIEF DESCRIPTION OF DRAWINGS

[0016] The accompanying drawings are included to provide a further understanding of the embodiments of the application, and constitute a part of the specification, and are used to explain the embodiments of the application together with the following specific embodiments, but do not constitute a limitation of the embodiments of the application. For those skilled in the art, other drawings can be obtained from the structures shown in the drawings without creative labor. In the drawings: Figure 1A hydraulic schematic diagram of the hydraulic system of the fork according to the specific embodiment of the present application.

[0017] Explanation of reference signs Specific embodiment

[0018] The specific embodiment of the present application is described in detail below with reference to the accompanying drawings. It should be understood that the specific embodiment described herein is only for illustration and explanation of the present application, and is not intended to limit the present application.

[0019] The fork hydraulic system and the forklift according to the present application are described below with reference to the accompanying drawings.

[0020] As mentioned above, in the prior art, the position of the fork tines is generally adjusted by manually moving the forks to achieve lateral shifting. However, in the era of mechanization, this manual operation is outdated, and efforts should be made to replace manual operation with automated machinery, so as to not only save the operator's physical strength and save operation time, but also make up for the demand for operation conditions that cannot be met by manpower.

[0021] To this end, the present application discloses a new type of fork hydraulic system applied to a forklift. As shown in Figure 1 In one specific embodiment, the fork hydraulic system comprises: a first oil cylinder 100 and a second oil cylinder 200, the rod cavities of the first oil cylinder 100 and the second oil cylinder 200 are in communication with each other, the rodless cavity of the first oil cylinder 100 is connected with a first lateral shifting working oil circuit L1, and the rodless cavity of the second oil cylinder 200 is connected with a second lateral shifting working oil circuit L2; a multi-way valve 20, the first lateral shifting working oil circuit L1 and the second lateral shifting working oil circuit L2 are hydraulically connected to the multi-way valve 20.

[0022] Among them, the first oil cylinder 100 and the second oil cylinder 200 are both driving oil cylinders for driving the fork tines to fold or unfold each other. In the present application, the two oil cylinders are connected in series, i.e. the rod cavities of the first oil cylinder 100 and the second oil cylinder 200 are in communication with each other, and the rodless cavities of each are connected with a working oil circuit, and high-pressure oil is introduced through the working oil circuit on one side, so as to drive the two oil cylinders to produce relative lateral shifting, thereby realizing lateral shifting hydraulic drive. This design can realize the adjustment of the distance between the fork tines by non-manual means, facilitate the adjustment of the tines for taking objects when the fork is empty, and at the same time can realize the adjustment of the left and right positions of the heavy object on the fork portal after the fork is loaded, and facilitate precise stacking of the heavy object.

[0023] Referring to Figure 1 , the fork hydraulic system further comprises: a folding working oil circuit L3 hydraulically connected to the rod cavity of the first oil cylinder 100 and the rod cavity of the second oil cylinder 200. The opening work oil path L4 is hydraulically connected to the rodless cavity of the first oil cylinder 100 and the rodless cavity of the second oil cylinder 200; The reversing valve 30 is used to connect the tool group oil path of the multi-way valve 20 to the first side shift work oil path L1, the second side shift work oil path L2, or alternatively to the closing work oil path L3 and the opening work oil path L4.

[0024] As shown in the figure, one side oil port of the reversing valve 30 is hydraulically connected to the tool group oil path of the multi-way valve 20, and the other side oil port is respectively hydraulically connected to the first side shift work oil path L1, the second side shift work oil path L2, the closing work oil path L3 and the opening work oil path L4. The pumped hydraulic oil of the hydraulic pump 10 is delivered to the reversing valve 30 through the output oil port (i.e. the tool group oil path) of a certain main valve disc of the multi-way valve 20, and through the reversing action of the main valve disc and the reversing valve 30, it can be selectively delivered to a certain work oil path, thereby driving the fork blade to realize the corresponding side shift action.

[0025] Among them, under the left valve position of the illustrated reversing valve 30, the pumped hydraulic oil can only flow to the closing work oil path L3 or the opening work oil path L4, and the first side shift work oil path L1 and the second side shift work oil path L2 are cut off or return oil, that is, only the fork closing action or the fork opening action can be performed, and the fork side shift action is locked. Among them, it is determined by a certain main valve disc of the multi-way valve 20 whether the pumped hydraulic oil flows to the closing work oil path L3 while the opening work oil path L4 returns oil, or flows to the opening work oil path L4 while the closing work oil path L3 returns oil.

[0026] Under the right valve position of the illustrated reversing valve 30, the pumped hydraulic oil of the hydraulic pump 10 can only flow to the first side shift work oil path L1 or the second side shift work oil path L2 through the tool group oil path and the reversing valve 30, and the closing work oil path L3 and the opening work oil path L4 are cut off or return oil, that is, only the fork side shift action can be performed, and the fork closing action or the fork opening action is locked. Similarly, it is determined by a certain main valve disc of the multi-way valve 20 whether the pumped hydraulic oil flows to the first side shift work oil path L1 while the second side shift work oil path L2 returns oil, or flows to the second side shift work oil path L2 while the first side shift work oil path L1 returns oil.

[0027] As can be seen, the fork hydraulic system of the present embodiment integrates the multi-action driving of synchronous closing, synchronous opening, synchronous left side shift and synchronous right side shift of the fork blade. Only one reversing valve and one hydraulic control valve group are used to realize the synchronous closing and opening and synchronous left and right side shift of the fork blade, and the system structure is simple and the function is sufficient.

[0028] Further, the fork hydraulic system of the present embodiment can further include: The on-off control valve 80 is used to control the cut-off or communication between the rodless cavity of the first oil cylinder 100 and the rodless cavity of the second oil cylinder 200.

[0029] By setting the on-off control valve 80, the oil passage of the two groups of movement modes of the fork closing and opening and synchronizing left and right side shifting can be isolated. When the fork performs the closing and opening action, the on-off control valve 80 is in the on state, and the C1 / C2 ports of the hydraulic control valve group shown in the dashed box are connected, that is, the two rodless cavities are connected; when the fork performs the side shifting action, the on-off control valve 80 is in the off state, and the C1 / C2 ports are not connected. This control method is simple, efficient and reliable, and can avoid the misoperation in the fork control process. The on-off control valve 80 can be controlled by an electromagnetic valve, but in the present embodiment, the on-off control valve 80 is set as a cartridge valve in the connecting oil passage between the opening working oil passage L4 and the second side shifting working oil passage L2. The cartridge valve is not only conducive to the large flow of oil, but also can realize automatic on-off control through hydraulic control, which will be described in detail below.

[0030] To realize the automatic hydraulic control of the on-off control valve 80, the fork hydraulic system can include: The shuttle valve 90, two comparison oil ports of the shuttle valve 90 are respectively hydraulically connected to the first side shifting working oil passage L1 and the second side shifting working oil passage L2, and the oil outlet is hydraulically connected to the control oil port of the cartridge valve.

[0031] By setting the shuttle valve 90, the high-pressure oil in the first side shifting working oil passage L1 and the second side shifting working oil passage L2 can be introduced into the control oil port of the cartridge valve as pilot oil. At the same time, it can also be used as a drain channel for the control oil port oil of the cartridge valve and be led out through the one-way valve 91. In this way, whether it is left side shifting or right side shifting, the cartridge valve can be locked, that is, the communication of the two rodless cavities is cut off. When the fork closing or opening action is performed, the cartridge valve cannot be locked due to the absence of high-pressure oil in the first side shifting working oil passage L1 and the second side shifting working oil passage L2, that is, the two rodless cavities can maintain communication.

[0032] In the present embodiment, the reversing valve 30 is a two-position six-way electromagnetic reversing valve, so that the operator can perform switching operation through the button before switching to the fork side shifting operation in combination with the vehicle electronic control system. Those skilled in the art can understand that the reversing valve 30 can also be selected as a hand control reversing valve or a hydraulic control reversing valve, etc., but will not be expanded here.

[0033] In this embodiment, the hydraulic valves in the first lateral movement working circuit L1, the second lateral movement working circuit L2, the closing working circuit L3, and the opening working circuit L4 are all arranged on the forks of the forklift, while the directional valve 30 is arranged at the boom head of the forklift. This design, placing the solenoid directional valve at the boom head and the hydraulically controlled valve assembly integrating various hydraulic valves on the forks, avoids placing too many hydraulic components at the boom head, resulting in a bulky structure. Placing the solenoid directional valve at the boom head also facilitates cable routing, avoiding the need for cables to extend to the forks, which would require the cables to be designed for movement and increase the risk of damage.

[0034] Furthermore, the fork hydraulic system may also include quick-change connectors 40, and the first lateral movement working oil circuit L1, the second lateral movement working oil circuit L2, the closing working oil circuit L3 and the opening working oil circuit L4 are respectively connected to the directional valve 30 through their respective quick-change connectors 40.

[0035] The pipeline between the solenoid directional valve at the boom head and the hydraulic control valve assembly on the forks uses a quick-connect 40mm coupling, allowing for quick insertion and removal and enabling rapid replacement of different attachments. At the same time, the solenoid directional valve at the boom head can adapt to different attachment operation requirements.

[0036] The hydraulic valves in each working oil circuit can be integrated into a hydraulic valve assembly as shown in the dashed box. For details, see [link to documentation]. Figure 1 The hydraulic valves in the first lateral displacement working oil circuit L1 and the second lateral displacement working oil circuit L2 both include a hydraulic lock 70. The hydraulic valves in the closing working oil circuit L3 and the opening working oil circuit L4 both include a speed control valve 50, a relief valve 60, and a hydraulic lock 70. The hydraulic lock 70 is used as a balance valve in the closing working oil circuit L3 and the opening working oil circuit L4. The relief valve 60 is used for high-pressure side to low-pressure side relief between the closing working oil circuit L3 and the opening working oil circuit L4. The speed control valve 50 is used to control the flow rate of the oil circuit. It can be seen that the hydraulic control valve group contains two speed control valves, two relief valves, one shuttle valve, one check valve 91, one damper, two bidirectional hydraulic locks, and one cartridge valve.

[0037] By incorporating two overflow valves, damage to structural and hydraulic components due to overpressure during the fork's closing and opening process can be prevented. Two sets of hydraulic locks (6.1 and 6.2) prevent the fork cylinders from moving freely in non-operational states, while ensuring that the two working oil circuits D1 / D4 and D2 / D3 operate independently without interference. The design of two sets of bidirectional hydraulic locks to mutually isolate the two sets of actuation oil circuits avoids oil circuit interference. A cartridge valve is designed to switch between the two sets of fork movements; this design is simple, reliable, efficient, and prevents malfunctions.

[0038] The following combination Figure 1 The working process of the fork hydraulic system is explained in detail.

[0039] In the case of the electromagnetic iron Y1 of the reversing valve 30 losing power, the pressure oil is output through the A oil port of the tool group oil path of the multi-way valve 20, reaches the P1 oil port of the reversing valve 30, reaches the D1 oil port of the hydraulic control valve group through the V1 oil port of the reversing valve 30, reaches the hydraulic lock 70 through the speed regulating valve 50 in the hydraulic control valve group, and is output to the rod cavity of the two fork oil cylinders through the C3 port, so that the two oil cylinders retract, and the fork closing action is realized.

[0040] In the case of the electromagnetic iron Y1 of the reversing valve 30 losing power, the pressure oil is output through the B oil port of the tool group oil path of the multi-way valve 20, reaches the P2 oil port of the electromagnetic reversing valve, reaches the D4 oil port of the hydraulic control valve group through the C4 oil port of the electromagnetic reversing valve, reaches the hydraulic lock 70 through the speed regulating valve 50 of the hydraulic control valve group, and is output to the rod cavity of the two fork oil cylinders through the C2 / C1 ports after being divided, so that the two oil cylinders extend, and the fork opening action is realized.

[0041] In the case of the electromagnetic iron Y1 of the electromagnetic reversing valve 30 being powered, the pressure oil is output through the A oil port of the tool group oil path of the multi-way valve 20, reaches the P1 oil port of the electromagnetic reversing valve, reaches the D2 oil port of the hydraulic control valve group through the C2 oil port of the electromagnetic reversing valve, and is output to the rod cavity of the second oil cylinder 200 through the C1 port of the hydraulic lock 50 in the hydraulic control valve group, so that the second oil cylinder 200 extends and the first oil cylinder 100 retracts due to the series connection of the two fork oil cylinders, and the fork synchronous left movement action is realized.

[0042] In the case of the electromagnetic iron Y1 of the electromagnetic reversing valve 30 being powered, the pressure oil is output through the B oil port of the tool group oil path of the multi-way valve 20, reaches the P2 oil port of the electromagnetic reversing valve, reaches the D3 oil port of the hydraulic control valve group through the C3 oil port of the electromagnetic reversing valve, and is output to the rod cavity of the first oil cylinder 100 through the C2 port of the hydraulic lock 70 in the hydraulic control valve group, so that the first oil cylinder 100 extends and the second oil cylinder 200 retracts due to the series connection of the two fork oil cylinders, and the fork synchronous right movement action is realized.

[0043] The application also protects a forklift truck comprising the above-mentioned fork hydraulic system. As can be seen, the application arranges a reversing valve at the head of the boom and a hydraulic control valve group at the fork, thereby forming a hydraulic system capable of controlling the lateral movement of the fork. The power oil source of the hydraulic system for controlling the lateral movement of the fork can be provided by the plunger pump of the whole vehicle hydraulic system and output through the accessory group oil way of the multi-way valve 20. The A / B oil port of the accessory group oil way of the multi-way valve is in communication with the P1 / P2 port of the electromagnetic reversing valve arranged at the head of the boom. The electromagnetic reversing valve arranged at the head of the boom is a two-position six-way reversing valve, and the V1 / V2 / V3 / V4 oil port thereof is in communication with the D1 / D2 / D3 / D4 oil port of the hydraulic control valve group arranged at the fork, and the connection mode is to use the quick-change connector 40 to connect, which can realize quick insertion and quick removal and facilitate accessory replacement. The C1 / C2 / C3 oil port of the hydraulic control valve group arranged at the fork is connected with the rodless cavity of the second oil cylinder 200, the rod cavity of the two fork oil cylinders and the rodless cavity of the first oil cylinder 100, respectively.

[0044] The forklift truck and the fork hydraulic system thereof of the application replace manual work with automatic mechanical work, save physical strength, avoid the frequent adjustment of the distance between the forks by the operator between the cab and the forks, save operation time and improve efficiency, solve the problem that the heavy object cannot be moved left and right on the forks after the forks are loaded, use plug-in valves to isolate the oil ways of the two actions of the forks, avoid the occurrence of misoperation, and control in a simple, efficient and reliable manner.

[0045] It should be noted that the hydraulic control valve group can be replaced by an electric control valve group or a manual control valve group, and the electromagnetic valves are combined with each other or the mechanical valves are combined with each other to control the oil circuit, so as to control the action of the fork. Any valve group that can control the oil circuit to control the action of the fork can be used.

[0046] In the description of the application, it should be understood that the terms "first" and "second" are only used for the purpose of description and cannot be understood as indicating or implying relative importance or implicitly indicating the number of the indicated technical features. Therefore, the features defined as "first" and "second" can explicitly or implicitly include at least one of the features. In the description of the application, the meaning of "a plurality of" is at least two, such as two, three, etc., unless otherwise specifically limited.

[0047] In this application, unless otherwise explicitly specified and limited, the terms "mounting", "connection", "connecting", "fixed", and the like should be understood broadly, for example, can be fixed connection, can also be detachable connection, or integrated; can be mechanical connection, can also be electrical connection or communication with each other; can be directly connected, can also be indirectly connected through an intermediate medium, can be the internal communication of two elements or the interaction relationship between two elements, unless otherwise explicitly limited. For those skilled in the art, the specific meaning of the above terms in this application can be understood according to the specific circumstances.

[0048] In the description of this specification, the description of the terms "one embodiment", "some embodiments", "example", "specific example", or "some examples" and the like means that the specific features, structures, materials or characteristics described in conjunction with the embodiment or example are included in at least one embodiment or example of the present application. In this specification, the illustrative description of the above terms does not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials or characteristics described can be combined in any appropriate manner in any one or more embodiments or examples. Furthermore, those skilled in the art can combine and combine the different embodiments or examples described in this specification and the features of the different embodiments or examples without contradiction.

Claims

1. A hydraulic system for forks, applied to forklift trucks, characterized in that, The fork hydraulic system includes: The first hydraulic cylinder (100) and the second hydraulic cylinder (200) are connected to each other by rod chambers. The rodless chamber of the first hydraulic cylinder (100) is connected to a first lateral movement working oil circuit (L1), and the rodless chamber of the second hydraulic cylinder (200) is connected to a second lateral movement working oil circuit (L2). A multi-way valve (20) is hydraulically connected to the first lateral shift working oil passage (L1) and the second lateral shift working oil passage (L2).

2. The fork hydraulic system according to claim 1, characterized in that, The fork hydraulic system includes: Close the working oil circuit (L3), which is hydraulically connected to the rod chamber of the first oil cylinder (100) and the rod chamber of the second oil cylinder (200); Open the working oil circuit (L4), which is hydraulically connected to the rodless chamber of the first oil cylinder (100) and the rodless chamber of the second oil cylinder (200); A reversing valve (30) is used to connect the attachment group oil circuit of the multi-way valve (20) to the first side-shifting working oil circuit (L1) and the second side-shifting working oil circuit (L2), or to switch to the closing working oil circuit (L3) and the opening working oil circuit (L4).

3. The fork hydraulic system according to claim 2, characterized in that, The fork hydraulic system includes: An on / off control valve (80) is used to control the cut-off or connection between the rodless chamber of the first cylinder (100) and the rodless chamber of the second cylinder (200).

4. The fork hydraulic system according to claim 2, characterized in that, The on / off control valve (80) is a cartridge valve installed in the connecting oil circuit between the opening working oil circuit (L4) and the second side-shifting working oil circuit (L2).

5. The fork hydraulic system according to claim 4, characterized in that, The fork hydraulic system includes: The shuttle valve (90) has two comparison ports that are hydraulically connected to the first side-shift working oil circuit (L1) and the second side-shift working oil circuit (L2), respectively, and its outlet port is hydraulically connected to the control port of the cartridge valve.

6. The fork hydraulic system according to claim 2, characterized in that, The reversing valve (30) is a two-position six-way electromagnetic reversing valve.

7. The fork hydraulic system according to any one of claims 2 to 6, characterized in that, The hydraulic valves in the first lateral shift working oil circuit (L1), the second lateral shift working oil circuit (L2), the closing working oil circuit (L3), and the opening working oil circuit (L4) are all arranged on the forks of the forklift truck, and the reversing valve (30) is arranged at the boom head of the forklift truck.

8. The fork hydraulic system according to claim 7, characterized in that, The fork hydraulic system includes: The quick-change connector (40) is used to connect the first lateral shift working oil passage (L1), the second lateral shift working oil passage (L2), the closing working oil passage (L3), and the opening working oil passage (L4) to the reversing valve (30) through their respective quick-change connectors (40).

9. The fork hydraulic system according to claim 7, characterized in that, The hydraulic valves in the first lateral shift working oil circuit (L1) and the second lateral shift working oil circuit (L2) each include a hydraulic lock (70), and the hydraulic valves in the closing working oil circuit (L3) and the opening working oil circuit (L4) each include a speed regulating valve (50), a relief valve (60) and a hydraulic lock (70).

10. A forklift, characterized in that, The forklift truck includes a fork hydraulic system according to any one of claims 1 to 9.

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