阅读说明：本技术 一种叉车 (Forklift truck ) 是由 不公告发明人 于 2018-02-10 设计创作，主要内容包括：本发明涉及一种叉车,叉车的控制装置包括液压泵、油箱、手动换向阀、起升油缸、货叉、叉架、链条、链轮和门架,所述液压泵的进油口与油箱连通,液压泵的出油口与手动换向阀的进油口P口连通；还包括液控换向阀和控制液压泵；所述控制液压泵的进油口与油箱连通；控制液压泵的出油口与液控换向阀的控制口K口连通；所述手动换向阀的执行口A口与液控换向阀的进油口P口连通；所述液控换向阀的执行口A口与起升油缸的无杆腔连通；当液控换向阀的控制口K口通入压力油时,液控换向阀的进油口P口与执行口A口相通；当液控换向阀的控制口K口未通入压力油时,液控换向阀的执行口A口与油箱相通。本发明可在发动机熄火时货叉自动下降着地。(The invention relates to a forklift, wherein a control device of the forklift comprises a hydraulic pump, an oil tank, a manual reversing valve, a lifting oil cylinder, a pallet fork, a fork frame, a chain wheel and a gantry, wherein an oil inlet of the hydraulic pump is communicated with the oil tank, and an oil outlet of the hydraulic pump is communicated with an oil inlet P port of the manual reversing valve; the hydraulic control reversing valve and the control hydraulic pump are also included; an oil inlet of the control hydraulic pump is communicated with an oil tank; the oil outlet of the control hydraulic pump is communicated with a control port K of the hydraulic control reversing valve; an execution port A of the manual reversing valve is communicated with an oil inlet P of the hydraulic control reversing valve; an execution port A of the hydraulic control reversing valve is communicated with a rodless cavity of the lifting oil cylinder; when pressure oil is introduced into a control port K of the hydraulic control reversing valve, an oil inlet P port of the hydraulic control reversing valve is communicated with an execution port A; when the control port K of the hydraulic control reversing valve is not filled with pressure oil, the execution port A of the hydraulic control reversing valve is communicated with the oil tank. The invention can automatically descend and land when the engine is shut down.)

1. A forklift comprises a fork control device, wherein the fork control device comprises a hydraulic pump (100), an oil tank (101), a manual reversing valve (102), a lifting oil cylinder (103), a fork (104), a fork frame (105), a chain (106), a chain wheel (107) and a portal frame (108), an oil inlet of the hydraulic pump (100) is communicated with the oil tank (101), and an oil outlet of the hydraulic pump (100) is communicated with an oil inlet P port of the manual reversing valve (102); the forks (104) are connected to a fork carriage (105); a cylinder body (103-2) of the lifting oil cylinder (103) is connected to the gantry (108); the chain wheel (107) is rotatably connected to the end of a piston rod (103-1) of the lifting oil cylinder (103), one end of the chain (106) is fixedly connected with the fork frame (105), and after the chain (106) bypasses the chain wheel (107) at the end of the piston rod (103-1) of the lifting oil cylinder (103), the other end of the chain (106) is fixedly connected to the door frame (108); the method is characterized in that: the hydraulic control reversing valve also comprises a hydraulic control reversing valve (1) and a control hydraulic pump (2); an oil inlet of the control hydraulic pump (2) is communicated with an oil tank (101); an oil outlet of the control hydraulic pump (2) is communicated with a control port K of the hydraulic control reversing valve (1); an execution port A of the manual reversing valve (102) is communicated with an oil inlet P of the hydraulic control reversing valve (1); an execution port A of the hydraulic control reversing valve (1) is communicated with a rodless cavity of the lifting oil cylinder (103);

when pressure oil is introduced into a control port K of the hydraulic control reversing valve (1), an oil inlet P of the hydraulic control reversing valve (1) is communicated with an execution port A; when pressure oil is not introduced into a control port K of the hydraulic control reversing valve (1), an execution port A of the hydraulic control reversing valve (1) is communicated with an oil tank (101);

the fork control device also comprises a safety valve (3) and a filter (4); the safety valve (3) is arranged on an oil channel from an oil outlet of the control hydraulic pump (2) to the oil tank (101); the filter (4) is arranged on an oil channel from the oil tank (101) to an oil inlet of the control hydraulic pump (2).

2. The lift truck of claim 1, wherein: when an engine is shut down, the oil outlet of the hydraulic pump (2) can not output pressure oil, no pressure oil enters the control port K of the hydraulic control reversing valve (1), the oil inlet port P of the hydraulic control reversing valve (1) is not communicated with the execution port A, but the execution port A of the hydraulic control reversing valve (1) is communicated with the oil tank (101), at this time, even if a driver forgets to operate the manual reversing valve (102) when the driver leaves the vehicle, the execution port A of the manual reversing valve (102) is communicated with the oil tank (101), at this time, the execution port A of the manual reversing valve (102) is not communicated with the oil inlet port P or is not communicated with the oil return port T, the pressure oil of a rodless cavity of the lifting oil cylinder (103) can also enter the oil tank (101) through the hydraulic control reversing valve (1), and a piston rod (103-1) of the lifting oil cylinder (103) retracts under the action of the gravity of goods on a fork (104), a fork (105) and the fork (104), the fork carriage (105) drives the fork (104) to descend and land through the chain (106) and the chain wheel (107).

Technical Field

The invention relates to a forklift.

Background

The safe operation regulation of the forklift provides that when the forklift leaves, the fork is descended to the ground, the gear handle is placed at a neutral position, the engine is flamed out, the power supply is cut off, the hand brake is pulled well, and when the forklift parks on a ramp, the wheels are also required to be cushioned by the cushion blocks. The fork control device of the prior art forklift is shown in fig. 2, and comprises a hydraulic pump 100, an oil tank 101, a manual directional control valve 102, a lifting cylinder 103, a fork 104, a fork frame 105, a chain 106, a chain wheel 107 and a portal frame 108, wherein an oil inlet of the hydraulic pump 100 is communicated with the oil tank 101, an oil outlet of the hydraulic pump 100 is communicated with an oil inlet port P of the manual directional control valve 102, an execution port a of the manual directional control valve 102 is communicated with a rodless cavity of the lifting cylinder 103, the fork 104 is connected to the fork frame 105, a cylinder body 103-2 of the lifting cylinder 103 is connected to the portal frame 108, the chain wheel 107 is rotatably connected to an end of a piston rod 103-1 of the lifting cylinder 103, one end of the chain 106 is connected to the fork frame 105, and the other end of the chain 106 is fixed to the portal frame 108. When the piston rod 103-1 of the lift cylinder 103 is extended or retracted, the fork 105 is raised or lowered along the mast 108 by the chain 106 and the sprocket 107. When the pallet fork 104 needs to ascend, only the manual reversing valve 102 needs to be operated, so that an oil inlet P port of the manual reversing valve 102 is communicated with an execution port A port, pressure oil in the hydraulic pump 100 enters a rodless cavity of the lifting oil cylinder 103, a piston rod 103-1 of the lifting oil cylinder 103 extends out, and the fork carriage 105 drives the pallet fork 104 to ascend through a chain 106 and a chain wheel 107; when the pallet fork 104 rises to a required position, the opening A of the execution port of the manual reversing valve 102 is not communicated with the opening P of the oil inlet and is not communicated with the opening T of the oil return port, at this time, pressure oil in the hydraulic pump 100 can not enter a rodless cavity of the lifting oil cylinder 103, pressure oil in the rodless cavity of the lifting oil cylinder 103 can not enter the oil tank 101, a piston rod 103-1 of the lifting oil cylinder 103 can not extend or retract any more, and the pallet fork 104 can not rise or fall any more; when a driver needs to put off and leave the vehicle, the fork 104 needs to be descended to the ground, the manual reversing valve 102 can be operated, an execution port A of the manual reversing valve 102 is communicated with an oil return port T, pressure oil of a rodless cavity of the lifting oil cylinder 103 enters the oil tank 101, a piston rod 103-1 of the lifting oil cylinder 103 retracts under the action of the gravity of the fork 104, the fork frame 105 and goods on the fork 104, and the fork frame 105 drives the fork 104 to descend through the chain 106 and the chain wheel 107. When the engine of the fork control device of the forklift is shut down, the fork 104 cannot automatically descend, and the fork can descend only by manually operating the manual reversing valve 102 to communicate the execution port A of the manual reversing valve 102 with the oil return port T. When a driver forgets to operate the manual reversing valve 102 when leaving the vehicle, the port A of the execution port of the manual reversing valve 102 is communicated with the oil tank 101 (at the moment, the port A of the execution port of the manual reversing valve 102 is not communicated with the port P of the oil inlet and is not communicated with the port T of the oil return port), at the moment, pressure oil in a rodless cavity of the lifting oil cylinder 103 cannot enter the oil tank 101, the fork 104 cannot descend, namely the fork 104 is still in a lifting state, at the moment, the engine is directly stopped and leaves the vehicle, the fork does not descend and lands, potential safety hazards exist, and the safety operation regulations of the forklift are not met.

Disclosure of Invention

The invention aims to provide a forklift with a fork capable of automatically descending and landing when an engine is shut down.

In order to achieve the purpose, the invention adopts the following technical scheme: a forklift comprises a fork control device, wherein the fork control device comprises a hydraulic pump, an oil tank, a manual reversing valve, a lifting oil cylinder, a fork frame, a chain wheel and a gantry; the forks are connected to the fork carriage; the cylinder body of the lifting oil cylinder is connected to the gantry; the chain wheel is rotationally connected to the end of the piston rod of the lifting oil cylinder, one end of the chain is fixedly connected with the fork frame, and the other end of the chain is fixedly connected to the gantry after the chain bypasses the chain wheel at the end of the piston rod of the lifting oil cylinder; the hydraulic control reversing valve and the control hydraulic pump are also included; an oil inlet of the control hydraulic pump is communicated with an oil tank; the oil outlet of the control hydraulic pump is communicated with a control port K of the hydraulic control reversing valve; an execution port A of the manual reversing valve is communicated with an oil inlet P of the hydraulic control reversing valve; an execution port A of the hydraulic control reversing valve is communicated with a rodless cavity of the lifting oil cylinder; when pressure oil is introduced into a control port K of the hydraulic control reversing valve, an oil inlet P port of the hydraulic control reversing valve is communicated with an execution port A; when the control port K of the hydraulic control reversing valve is not filled with pressure oil, the execution port A of the hydraulic control reversing valve is communicated with the oil tank.

Also includes a safety valve; the safety valve is arranged on an oil channel from an oil outlet of the control hydraulic pump to the oil tank.

The device also comprises a filter; the filter is arranged on an oil channel from the oil tank to an oil inlet of the control hydraulic pump.

The invention has the following positive effects: (1) the oil outlet of the control hydraulic pump is communicated with the control port K of the hydraulic control reversing valve; an execution port A of the manual reversing valve is communicated with an oil inlet P of the hydraulic control reversing valve; an execution port A of the hydraulic control reversing valve is communicated with a rodless cavity of the lifting oil cylinder; when the hydraulic lifting device is used, the power input shaft of the control hydraulic pump 2 is in transmission connection with the crankshaft of the engine of a vehicle through the transmission mechanism, so that after the engine is flamed out, the crankshaft of the engine does not rotate any more, the power input shaft of the control hydraulic pump does not rotate any more, the oil outlet of the control hydraulic pump cannot output pressure oil, no pressure oil enters the control port K of the hydraulic control reversing valve, the execution port A of the hydraulic control reversing valve is communicated with the oil tank, even if a driver forgets to communicate the execution port A of the manual reversing valve with the oil tank when the driver leaves the vehicle, the pressure oil in a rodless cavity of the lifting oil cylinder can enter the oil tank through the hydraulic control reversing valve, a piston rod of the lifting oil cylinder retracts under the action of the gravity of goods on the fork, the fork frame and the fork, and the fork frame is driven by the. Namely, the fork can automatically descend to land after the engine is flamed out, so that potential safety hazards can not exist, and the safety operation rules of the forklift are met.

Drawings

FIG. 1 is a schematic diagram of the present invention;

fig. 2 is a schematic diagram of a fork control device of a prior art forklift.

The reference numbers in the above figures are as follows: the hydraulic control directional control system comprises a hydraulic control directional control valve 1, a control hydraulic pump 2, a safety valve 3, a filter 4, a hydraulic pump 100, an oil tank 101, a manual directional control valve 102, a lifting oil cylinder 103, a piston rod 103-1, a cylinder body 103-2, a fork 104, a fork frame 105, a chain 106, a chain wheel 107 and a portal frame 108.

Detailed Description

The invention is further described below with reference to the accompanying drawings and the examples given.

As shown in fig. 1, a fork control device of a forklift comprises a hydraulic pump 100, an oil tank 101, a manual directional control valve 102, a lifting oil cylinder 103, a fork 104, a fork frame 105, a chain 106, a chain wheel 107 and a portal frame 108, wherein an oil inlet of the hydraulic pump 100 is communicated with the oil tank 101, and an oil outlet of the hydraulic pump 100 is communicated with an oil inlet P of the manual directional control valve 102; the forks 104 are attached to a fork carriage 105; the cylinder body 103-2 of the lifting oil cylinder 103 is connected to the portal 108; the chain wheel 107 is rotatably connected to the end of the piston rod 103-1 of the lifting cylinder 103, one end of the chain 106 is fixedly connected with the fork frame 105, and after the chain 106 bypasses the chain wheel 107 at the end of the piston rod 103-1 of the lifting cylinder 103, the other end of the chain 106 is fixedly connected to the door frame 108; the hydraulic control reversing valve also comprises a hydraulic control reversing valve 1 and a control hydraulic pump 2; an oil inlet of the control hydraulic pump 2 is communicated with an oil tank 101; the oil outlet of the control hydraulic pump 2 is communicated with a control port K of the hydraulic control reversing valve 1; an execution port A of the manual reversing valve 102 is communicated with an oil inlet P of the hydraulic control reversing valve 1; an execution port A of the hydraulic control reversing valve 1 is communicated with a rodless cavity of the lifting oil cylinder 103; when pressure oil is introduced into a control port K of the hydraulic control reversing valve 1, an oil inlet P of the hydraulic control reversing valve 1 is communicated with an execution port A; when the control port K of the hydraulic control reversing valve 1 is not filled with pressure oil, the execution port A of the hydraulic control reversing valve 1 is communicated with the oil tank 101.

Also comprises a safety valve 3; the relief valve 3 is disposed on an oil passage from an oil outlet of the control hydraulic pump 2 to the oil tank 101.

Also comprises a filter 4; the filter 4 is arranged on an oil passage from the oil tank 101 to an oil inlet of the control hydraulic pump 2.

When the hydraulic oil pressure control device is used, the power input shaft of the control hydraulic pump 2 is in transmission connection with a crankshaft of an engine of a vehicle through a transmission mechanism, specifically, a crankshaft belt pulley is arranged on the crankshaft of the engine, a hydraulic pump belt pulley is arranged on the power input shaft of the control hydraulic pump 2, and a belt is wound on the crankshaft belt pulley and the hydraulic pump belt pulley, so that when the crankshaft of the engine rotates, the power input shaft of the control hydraulic pump 2 is driven to rotate through the crankshaft belt pulley, the belt and the hydraulic pump belt pulley in sequence, and when the power input shaft of the control hydraulic pump 2 rotates, an oil outlet of the control hydraulic pump 2 can output pressure oil. When the engine is not flamed out, the crankshaft of the engine rotates, and as the power input shaft of the control hydraulic pump 2 is in transmission connection with the crankshaft of the engine of the vehicle through the transmission mechanism, the power input shaft of the control hydraulic pump 2 can also rotate, and the oil outlet of the control hydraulic pump 2 can output pressure oil; when the engine is flamed out, the crankshaft of the engine cannot rotate, the power input shaft of the control hydraulic pump 2 cannot rotate, and the oil outlet of the control hydraulic pump 2 cannot output pressure oil.

The working principle of the invention is as follows: when the engine is not shut down, the oil outlet of the hydraulic pump 2 is controlled to output pressure oil; the pressure oil output by the oil outlet of the control hydraulic pump 2 enters the control port K of the hydraulic control reversing valve 1, at the moment, the oil inlet P of the hydraulic control reversing valve 1 is communicated with the execution port A, and when the fork 104 needs to ascend or descend, the operation can be finished only by operating the manual reversing valve 102.

When the engine is shut down, the oil outlet of the control hydraulic pump 2 can not output pressure oil, no pressure oil enters the control port K of the hydraulic control reversing valve 1, the oil inlet P port of the hydraulic control reversing valve 1 is not communicated with the execution port A, instead, the port a of the execution port of the hydraulic control directional control valve 1 is communicated with the oil tank 101, and even if a driver forgets to operate the manual directional control valve 102 when leaving the vehicle, the port a of the execution port of the manual directional control valve 102 is communicated with the oil tank 101 (at this time, the port a of the execution port of the manual directional control valve 102 is not communicated with the port P of the oil inlet and is not communicated with the port T of the oil return port), the pressure oil in the rodless cavity of the lifting oil cylinder 103 can also enter the oil tank 101 through the hydraulic control directional control valve 1, the piston rod 103-1 of the lift cylinder 103 is retracted by the gravity of the fork 104, the fork frame 105 and the load on the fork 104, fork carriage 105 carries forks 104 down to the ground via chain 106 and sprocket 107. Namely, the fork can automatically descend to land after the engine is flamed out, so that potential safety hazards can not exist, and the safety operation rules of the forklift are met.