JP2010132414A - Cargo handling vehicle - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To prevent a retreat of a vehicle body when starting in climbing travel. <P>SOLUTION: A forklift has a lift device, a traveling device and a braking mechanism, and has an inching pressure switch 40 for detecting the stepping of a second brake pedal 33a having an inching function in an intermediate detecting position, a lift detecting pressure switch for detecting that a cargo handling operation lever 42a is operated to the lift side, and a select valve capable of stopping, connecting and separating by supplying a hydraulic fluid to an advance-retreat clutch by an advance-retreat lever, and is constituted so that the select valve stops the supply of hydraulic fluid pressure to the clutch by the detection of the lift detecting pressure switch and the inching pressure switch 40. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a cargo handling vehicle having a brake pedal provided with an inching mechanism capable of moving back and forth at a slow speed.

  For engine-driven loading and unloading vehicles, use when the engine speed is high during high-load loading work and when it is necessary to move forward and backward at a slow speed or to start quietly with less impact on the vehicle body An inching mechanism is installed.

  For example, in the driver's seat of a forklift (truck), as shown in FIG. 6, from the left side to the right side of the floor, a left brake pedal 11 that can be inched and a right brake pedal 12 that brakes while the clutches 24 and 25 are connected. The accelerator pedal 13 is arranged side by side, and in normal traveling work and cargo handling work, the left brake pedal 11 is depressed with the left foot and the accelerator pedal 13 is depressed with the right foot.

  The forklift braking mechanism is configured such that the left and right brake valves 14 and 15 operated by the left and right brake pedals 11 and 12 respectively, and the left and right brake valves 14 and 15 are respectively operated from the air tank 16 via the double check valve 17. An air over hydraulic brake 18 that is operated by supplying high pressure air, a power transmission mechanism 19 for transmitting power from the engine to the wheels, and a pressure that is operated by the high pressure air sent from the left brake valve 14. And a switch 20.

  The brake 18 is operated by supplying high-pressure air from the double check valve 17 via the booster 21. The power transmission mechanism 19 is interposed between the hydraulic pump 23 for supplying the hydraulic pressure for operation from the oil tank 22 and the hydraulic pump 23 and the forward clutch 24 and the reverse clutch 25, and a travel shift lever (not shown). And a select valve 26 for forward / reverse switching and an inching valve 27 that is electromagnetically controlled by the pressure switch 20. As shown in FIG. 6C, the pressure switch 20 and the solenoid S of the inching valve 27 are connected in series.

  In the above configuration, when the left brake pedal 11 is depressed with the left foot, the left brake valve 14 is opened, and high-pressure air is supplied from the air tank 16 to the brake 18 via the double check valve 17 and the booster 21, and the wheels are operated. Braked. When further depressed, the pressure switch 20 is turned on by the high pressure air from the air tank 16 and the inching valve 27 is operated, the supply of the hydraulic pressure for operation is stopped, the forward clutch 24 or the reverse clutch 25 is separated, and the power transmission is stopped. Is done. When the right brake pedal 12 is depressed, the brake valve 15 is opened, and high-pressure air is supplied from the air tank 16 to the brake 18 via the double check valve 17 and the booster 21, and the forward / reverse clutch 24 or 25 is supplied. The wheel is braked in a state where is separated.

As described above, the inching mechanism depresses the left brake pedal 11 for the entire stroke, brakes the wheel in a state where the forward and reverse clutches 24 or 25 are separated, and stops the vehicle body, and then selects the select valve 26 by the travel shift lever. Is operated to connect the forward clutch 24 (or the reverse clutch 25), and in the forward state (or reverse state), the left brake pedal 11 is gradually returned to turn off the pressure switch 20 and the forward clutch 24 (or reverse). The clutch 25) is connected, and the pressure switch 20 is turned on and off by repeatedly returning and stepping on the left brake pedal 11 at that position, thereby setting the forward clutch 24 (or the reverse clutch 25) in a half-clutch state. The vehicle body moves forward and backward at a slow speed.
Japanese Patent Laid-Open No. 2001-348198 (FIG. 2)

  However, when the left brake pedal 11 is depressed during climbing, the clutches 24 and 25 are separated by the inching function and the wheels are braked. Therefore, even when the left brake pedal 11 is released and the accelerator pedal 13 is depressed at the time of starting. There is a problem that the vehicle body moves backward due to the time lag between the release of braking and the starting operation.

  SUMMARY OF THE INVENTION An object of the present invention is to provide a cargo handling vehicle that solves the above-described problems and can prevent the vehicle body from retreating when starting uphill.

  According to a first aspect of the present invention, there is provided a hydraulic pressure generator driven by an engine, a cargo handling device driven by hydraulic pressure supplied from the hydraulic pressure generator, and a driving force of the engine from a torque converter to a traveling wheel via a clutch. An inching operation detection unit for detecting a depression operation of an inching brake pedal, and an engine in a cargo handling vehicle including a power transmission mechanism for transmitting and a braking mechanism capable of braking a traveling wheel with a clutch connected by an inching brake pedal. A cargo handling operation detection unit that detects that the cargo handling operation device has been operated on the drive operation side that drives at a high speed and drives the cargo handling device, and is operated by a forward / reverse operation device to supply and stop hydraulic pressure for operation to the clutch. A forward / reverse switching valve that can be connected and separated, and the forward / reverse switching valve is connected to the cargo handling operation detector by the cargo handling operation detection unit. At the same time that the operation to the drive operation side is detected, the inching brake pedal is detected at the intermediate detection position by the inching operation detection unit, and the supply of operating hydraulic pressure to the clutch is stopped and the clutch is separated. It has been done.

  According to a second aspect of the present invention, in the configuration of the first aspect, the cargo handling operation detector is a pressure switch that detects the hydraulic pressure of a pilot valve operated by the cargo handler, and the inching operation detector is an inching brake pedal. The pressure switch detects a stepping operation based on the fluid pressure discharged from the pilot valve to be operated, or the position detection switch detects the stepping operation based on the stepping position of the inching brake pedal.

  According to a third aspect of the present invention, in the configuration according to the first or second aspect, the brake mechanism is a hydraulic drive that brakes the traveling wheel with a drive oil supplied from a hydraulic pump or a hydraulic accumulator by operating an inching brake pedal. This is an air drive type that brakes a traveling wheel with high-pressure air supplied from an air pressure accumulator.

  According to the first aspect of the present invention, during normal braking by the inching brake pedal, the clutch is maintained in the connected state, so that the vehicle body can be prevented from retreating when starting uphill, and starting on a slope can be prevented. It can be performed smoothly and the vehicle body does not move backward.

  Further, during a cargo handling operation in which the engine rotates at a high speed, when the inching brake pedal is pushed through the operation detection position and the running wheel is braked to the step pressure limit to stop the vehicle body, this is detected by the inching operation detection unit. And if a cargo handling operation device is operated to the drive operation side, a cargo handling operation detection part will detect this. By the detection of the inching operation detection unit and the cargo handling operation detection unit, the forward / reverse switching valve is operated to stop the supply of hydraulic pressure for operation to the clutch, and the clutch is separated. Further, the inching brake pedal is returned to the depressing operation detection position, and the inching brake pedal is repeatedly depressed and returned before and after the depressing operation detection position. By repeatedly supplying and stopping the engine and engaging and disengaging the clutch to make it a half-clutch state, the power from the engine to the running wheels can be transmitted little by little, and the vehicle can move forward and backward at a slow speed. And inching operation can be performed smoothly.

  According to the configuration of claim 2, the cargo handling operation detection unit is a pressure switch that detects the hydraulic pressure of the pilot valve, and the inching operation detection unit is a pressure switch that detects the fluid pressure discharged from the pilot valve, or an inching brake pedal. By using the position detection switch for detecting the depression position, the cargo handling operation and the inching operation can be accurately detected.

  According to the configuration of the third aspect, even if the braking mechanism is a hydraulic drive type or an air drive type, the same effect can be obtained.

Embodiments of the present invention will be described below.
[Embodiment 1]
A first embodiment of a forklift that is a cargo handling vehicle equipped with an inching mechanism capable of moving back and forth at a slow speed will be described with reference to FIGS.

(Braking mechanism)
As shown in FIGS. 1 and 4, a forklift braking mechanism 31 includes a hydraulically driven disc brake device 34. The brake mechanism 31 is disposed on the right side of the floor of the driver's seat and operates on a first brake valve (spool valve) 32. The first brake pedal (normal brake pedal) 32a is disposed on the left side and the second brake valve. A second brake pedal (inching brake pedal) 33a for operating the (spool valve) 33, a hydraulic pump P1 driven by the engine E, the hydraulic pump P1 and the oil tank T, and the first and second brakes. Braking hydraulic pressure between the brake oil supply pipe 35A and the brake oil discharge pipe 35B for connecting the valves 32 and 33, the master cylinder 38 for operating the disc brake device 34, and the first and second brake valves 32 and 33, respectively. Brake oil supply / discharge pipe 36 that supplies and discharges hydraulic pressure, and a hydraulic accumulator that supplies braking hydraulic pressure when the hydraulic pump P1 is stopped (Hydraulic accumulator) has and a 37.

  A brake oil supply pipe 35A and a brake oil discharge pipe 35B are connected to the first brake valve 32 and the second brake valve 33, respectively, and the pilot operation of the first brake valve 32 is performed from the discharge port of the second brake valve 33. A pilot pipe 39 is connected to the port 32b. The pilot pipe 39 is provided with an inching pressure switch 40 which is an inching operation detection unit for detecting the pilot pressure, and is substantially at the center of the depression stroke between the depression pressure start position of the second brake pedal 33a and the depression pressure limit. Is set so that the inching pressure switch 40 is activated (turned on) by turning on the second brake valve 33 at the intermediate detection position (stepping operation detection position) set to.

  Instead of the inching pressure switch 40, an inching position detector (limit switch) LS that detects the depression operation of the second brake pedal 33a at the spool position of the first brake valve 32 may be used. In the case of this inching position detector LS, it is set to operate (on / off) at the intermediate detection position of the second brake pedal 33a.

(Handling device)
As shown in FIGS. 2 and 4, the cargo handling device includes a lift device 41 that lifts and lowers a fork (not shown) provided at the front of the vehicle body to perform a cargo handling operation. The lift device 41 is operated by a hydraulic pump (hydraulic pressure generating device) P2 driven by the engine E, a cargo handling operation lever (a cargo handling operator) 42a for operating the cargo handling pilot valve 42, and a cargo handling pilot valve 42. A lift valve 45 capable of supplying the drive hydraulic pressure supplied from the hydraulic pump P2 to the progress chamber of the lift cylinder 44, and a cargo handling operation detection unit that detects an operation state of the cargo handling operation lever 42a to the lift side (drive operation side). A lift detection pressure switch 47 is provided.

  A pilot pressure supply pipe 48A and a pilot pressure discharge pipe 48B are connected from the pilot hydraulic pump P3 and the oil tank T to the cargo handling pilot valve 42, respectively. When operated to the lift side, cargo handling pilot pipes 46A, 46B for supplying and discharging pilot oil from the discharge port of the cargo handling pilot valve 42 to the pilot operating portions 45a, 45b of the lift valve 45 are connected. A lift detection pressure switch 47 is provided in the cargo handling pilot pipe 46A that is pressurized when the cargo handling lever 42a is operated to the lift side. The lift cylinder 44 is connected to a lift hydraulic discharge pipe 43B that discharges drive hydraulic pressure from the progress chamber to the oil tank T when the fork is lowered.

(Power transmission mechanism)
FIG. 4 shows a power transmission mechanism that transmits the power of the engine E to the traveling wheels W. Between the engine E and the traveling wheels W, the torque converter TC, the forward clutch FC, and the reverse clutch RC are sequentially arranged from the engine E side. The forward and reverse speed reducers TM, the propeller shaft PS, the differential gear DG, and the axle shaft AS are interposed.

  A hydraulic pump P3 driven by the engine E is provided, and a clutch supply pipe 51A and a clutch discharge pipe 51B are respectively provided between the hydraulic pump P3 and the oil tank T and the forward and reverse clutches FC and RC. An electromagnetic select valve (forward / reverse switching valve) 53 is interposed between the clutch supply and discharge pipes 51A and 51B.

  FIG. 3 is a wiring diagram for operating the select valve 53. Wirings 54 and 54 are connected to the forward / reverse switch 52 operated by the forward / reverse lever 52a, respectively, and the forward relay 55F and the reverse relay are connected to the wirings 54 and 54, respectively. 55R is provided, and when the forward / reverse switch 52 is operated to the forward side or the reverse side by the forward / reverse lever 52a, the forward relay 55F or the reverse relay 55R is turned on to advance the forward solenoid FS of the select valve 53. Alternatively, the reverse solenoid RS is excited, and the hydraulic pressure for operation is sent to and connected to the forward clutch FC or the reverse clutch RC. Further, when the forward / reverse lever 52a is in the neutral position, the forward relay 55F or the reverse relay 55R is off and the forward solenoid FS or the reverse solenoid RS is not excited, and the forward and reverse clutches FC and RC are separated. It becomes a state.

  Further, an inching relay 56 that is always on (connected) is interposed in the wiring 54, and a contact 57 operated by the inching pressure switch 40 is connected to a wiring 57 that turns off the inching relay 56 when energized. An inching switch 40S and an a-contact lift detection switch 47S operated by a lift detection pressure switch 47 are interposed in series.

  Therefore, when the inching pressure switch 40 and the lift detection pressure switch 47 are turned on simultaneously and the inching switch 40S and the lift detection switch 47S are turned on, the inching relay 56 is turned off and the wiring 54 is de-energized. Even if the select valve 53 is on the forward side or the reverse side, the excitation of the forward solenoid FS or the reverse solenoid RS is stopped, so that the select valve 53 is returned to the neutral position, and the forward and reverse clutches FC and RC are engaged. To be separated.

(Description of operation)
In the above configuration, when the vehicle travels forward (or reverse), the forward / reverse switch 52 is operated to the forward side (or reverse side) by the forward / reverse lever 52a to excite the forward solenoid FS (or reverse solenoid RS). The valve 53 is operated forward (or backward). As a result, the hydraulic pressure for operation is supplied from the hydraulic pump P3 to the forward clutch FC (or the reverse clutch RC) and connected, and the power of the engine E is transmitted to the traveling wheels W to rotate and drive forward (or reverse). .

  When the first brake pedal 32a is depressed during traveling, the brake hydraulic pressure supplied from the hydraulic pump P1 is sent from the second brake valve 33 to the master cylinder 38, and the forward clutch FC or the reverse clutch RC is connected. In this state, the disc brake device 34 is operated to brake the traveling wheel W.

  When the second brake pedal 33a is depressed during traveling, the brake hydraulic pressure supplied from the hydraulic pump P1 is sent from the pilot pipe 39 to the pilot operation port 32b of the first brake valve 32 via the second brake valve 33. It is done. As a result, the first brake valve 32 is operated, the brake hydraulic pressure supplied from the hydraulic pump P1 is sent to the master cylinder 38, the disc brake device 34 is operated, and the traveling wheel W is braked.

  At this time, when the second brake pedal 33a is depressed beyond the intermediate detection position, the inching pressure switch 40 is actuated and the inching relay 56 is turned on, but when the cargo handling operation lever 42a is not operated to the lift side, Since the lift detection pressure switch 47 is in the OFF state, the select valve 53 is maintained in the forward or reverse operation state, and the connected state of the forward clutch FC or the reverse clutch RC is maintained.

  When traveling forward, the second brake pedal 33a is stepped on to the depression pressure limit to stop braking. When the lift operation is performed from this state, if the cargo handling operation lever 42a is operated to the lift side, the inching pressure switch 40, the lift detection pressure switch 47, Are turned on and the wiring 57 is energized. As a result, the inching relay 56 is turned off, the power supply to the forward solenoid FS (or the reverse solenoid RS) is stopped, and the selection valve 53 is returned to the neutral position, whereby the supply of the hydraulic pressure for operation is stopped and the forward clutch FC (or reverse clutch RC) is separated.

  Next, the second brake pedal 33a is slowly returned to the intermediate detection position, and the inching pressure switch 40 is turned on and off by alternately stepping on and returning the second brake pedal 33a with the intermediate detection position interposed therebetween. 56 is turned on and off, and the select valve 53 is alternately switched between the neutral position and the forward position (or reverse position). As a result, supply and discharge of the hydraulic pressure for operation to the forward clutch FC (or reverse clutch RC) are alternately repeated to enter a half-clutch state, and fine speed forward (or slow reverse) is possible.

  Here, the reason that the inching operation can be performed only at the time of the lift work is that a high load is applied to the hydraulic pump P2 during the lift operation of lifting the load via the fork, and the engine E is rotated at a high speed. When the forward clutch FC (or the reverse clutch RC) is directly connected in a state where the engine E is at a high speed in this way, the vehicle starts suddenly or gives a large impact to the load, making it difficult to control the traveling operation of the vehicle body. Because. Further, at the time of the down operation for lowering the fork, only the drive hydraulic pressure is discharged from the progress chamber of the lift cylinder 44, and therefore the rotational speed of the engine E does not increase. Further, even when the vehicle starts moving forward or backward from the stop, the rotational speed of the engine E does not increase, and it is only necessary to increase the rotational speed of the engine E to the rotational speed required for starting by the accelerator pedal. Therefore, at such a low rotational speed, even when the forward clutch FC (or the reverse clutch RC) is connected, the second brake pedal 33a is returned and the accelerator is stepped on moderately, so that the vehicle can move forward at a low speed ( Or reverse), and no impact is caused by starting. Also, the vehicle body does not slide down even when the vehicle starts moving uphill.

(Effect of embodiment)
According to the first embodiment, when the traveling wheel W is braked and stopped by depressing the second brake pedal 33a to the depression pressure limit, the inching pressure switch 40 is activated and the inching relay 56 is turned on. Since the switch 47 remains off, the forward or reverse clutches FC and RC are held in the connected state. Therefore, after climbing down the second brake pedal 33a and stopping the vehicle body, the forward / reverse lever 52a is operated to set the forward / reverse switch 52 to the forward side (or reverse side) and return the second brake pedal 33a. When the disc brake device 34 is released, the power of the engine E is transmitted to the traveling wheel W through the torque converter TC at the same time, so that the vehicle body is not retracted even in an uphill state, and the vehicle can start smoothly. it can.

  Here, if the fork loaded by operating the cargo handling operation lever 42a to the lift side is raised, a high load is applied to the engine E and the rotational speed is increased. When the second brake pedal 33a is depressed to the limit of the depression pressure and the inching pressure switch 40 is turned on, when the cargo handling operation lever 42a is operated to the lift side and the lift detection pressure switch 47 is turned on, the select valve 53 is neutral. Returning to the position, the forward clutch FC (or the reverse clutch RC) is separated.

  As a result, the depression of the second brake pedal 33a is returned to the intermediate detection position, and further, the inching relay 56 is turned on and off by repeating the depression and return of the second brake pedal 33a across the intermediate detection position. The clutch FC (or the reverse clutch RC) can be engaged / disengaged to enter the half-clutch state, and the clutch FC (or the reverse clutch RC) can move forward (or reverse) at a slow speed.

  Thus, even when traveling on a slope, the vehicle body can be reliably prevented from moving backward and started. In addition, even during the lift operation when the engine E is rotating at a high speed, the inching operation can be performed, and the vehicle can move forward and backward at a low speed in a half-clutch state, and can start smoothly without giving an impact to the load. it can.

[Embodiment 2]
A second embodiment having an air-driven drum brake device as a forklift braking mechanism will be described with reference to FIG. In the second embodiment, since FIGS. 2 to 4 of the first embodiment are the same, the description will be made with reference to FIGS.

(Braking mechanism)
As shown in FIGS. 4 and 5, the braking mechanism 61 includes a first brake pedal 62 a that is disposed on the right side of the floor portion of the driver seat and operates the first brake valve (spool valve) 62, and the floor portion of the driver seat. The second brake pedal 63a that is disposed on the left side of the vehicle and that can be operated by the inching operation to operate the second brake valve (spool valve) 63, the air-driven drum brake device 64 provided on each traveling wheel W, and the engine E An air compressor AC that is driven, an air reservoir (air type accumulator) 66 that accumulates braking high-pressure air from the air compressor AC via an air governor (pressure regulating valve) 65, and the air reservoir 66 and the first and second brake valves. The brake air supply pipes 67A and 67B that connect 62 and 63, respectively, and the first and second brake valves 62 and 63, respectively Double check valve 68 for merging the brake high-pressure air, and the brake air supply pipe 67C for supplying and discharging the brake high-pressure air from the double check valve 68 to the working cylinder 64a of the drum brake device 64 via the air booster 69. It is equipped with. An inching pressure switch 70 is provided in the brake air supply pipe 67B connected to the discharge port of the second brake valve 63. With this inching pressure switch 70, the stepping operation of the second brake pedal 63a is brought to the intermediate detection position. Reaching can be detected via air pressure. Instead of the inching pressure switch 70, the second brake valve 63 is provided with an inching position detector (limit switch) LS for detecting the depression operation of the second brake pedal 63a at the intermediate detection position of the depression stroke based on the pushing position of the spool. It may be provided.

(Description of operation)
In the above configuration, when the second brake pedal 63a is depressed during forward (reverse) traveling, the high-pressure air for braking supplied from the air reservoir 66 is supplied from the second brake valve 63 via the air booster 69 to the drum brake device 64. And the drum brake device 64 is actuated to brake the traveling wheel W.

  At this time, when the second brake pedal 63a is fully depressed beyond the intermediate detection position, the inching pressure switch 70 is activated and the inching relay 56 is turned on. At this time, if the cargo handling operation lever 42a is not operated to the lift side, the lift detection pressure switch 47 is not turned on, and the select valve 53 is maintained in the forward (or reverse) operation state and the forward clutch FC (or reverse). The connection state of the clutch RC) is maintained.

  In this state, when the cargo handling operation lever 42a is operated to the lift side in order to perform the cargo handling work, the lift detection pressure switch 47 is turned on, the inching relay 56 is turned off, and the inching pressure switch 70 and the lift detection pressure switch 47 are turned on. Thus, power supply to the forward solenoid FS (or the reverse solenoid RS) is stopped, the select valve 53 is returned to the neutral position, and the forward clutch FC (or the reverse clutch RC) is separated.

  When further starting, the inching pressure switch 70 is set by slowly returning the depression of the second brake pedal 63a to the intermediate detection position and further alternately depressing and returning the second brake pedal 63a across the intermediate detection position. Thus, the inching switch 70S is repeatedly turned on and off, whereby the inching relay 56 is repeatedly connected and disconnected, and the select valve 53 is switched between the neutral position and the forward position (or reverse position). Then, the supply and stop of the hydraulic pressure for operation to the forward clutch FC (or the reverse clutch RC) are repeated, and a half-clutch state is established, so that a slow forward (slow reverse) can be performed.

According to the above embodiment, even the braking mechanism 61 including the air-driven drum brake device 64 can achieve the same effects as those of the first embodiment.
In the first and second embodiments, the cargo handling vehicle is a forklift. However, the present invention is not limited to this, and an earthwork vehicle such as a wheel loader that moves forward and backward while performing cargo handling work may be used.

BRIEF DESCRIPTION OF THE DRAWINGS It is the block diagram which shows Embodiment 1 of the cargo handling vehicle which has an inching mechanism based on this invention, and shows a braking mechanism. It is a block diagram which shows the cargo handling apparatus of a cargo handling vehicle. It is an electrical wiring diagram which shows operation | movement of the inching pressure switch and lift detection pressure switch of a cargo handling vehicle. It is a block diagram which shows the power transmission mechanism of a cargo handling vehicle. It is a block diagram which shows Embodiment 2 of the cargo handling vehicle which has an inching mechanism based on this invention, and shows a braking mechanism. (A)-(c) shows the conventional inching apparatus, (a) is a braking mechanism, (b) is a power transmission mechanism, (c) is a wiring diagram.

Explanation of symbols

P1 to P3 Hydraulic pump T Oil tank E Engine FC Forward clutch FR Reverse clutch LS Inching position detector (Inching operation detector)
TC Torque converter FS Forward solenoid RS Reverse solenoid 32 First brake valve 32a First brake pedal 32b Pilot operation port 33 Second brake valve 33a Second brake pedal (inching brake pedal)
34 Disc brake device 37 Hydraulic accumulator 39 Pilot pipe 40 Inching pressure switch (Inching operation detection unit)
40S Inching Switch 41 Lifting Device 42 Pilot Valve 42a Cargo Handling Lever (Cargo Handling Operator)
44 Lift cylinder 45 Lift valves 45a and 45b Pilot operation parts 46A and 46B Pilot piping for cargo handling 47 Lift detection pressure switch (load handling operation detection part)
51A clutch supply pipe 51B clutch discharge pipe 52 forward / reverse switch 52a forward / reverse lever (forward / reverse actuator)
53 Select valve (Forward / backward switching valve)
56 inching relay 62 first brake valve 62a first brake pedal 63 second brake valve 63a second brake pedal (inching brake pedal)
64 Drum brake device 66 Air reservoir 67A, 67B Brake air supply pipe 68 Double check valve 70 Inching pressure switch (Inching operation detection unit)
70S inching switch

Claims (3)

A hydraulic pressure generator driven by the engine, a cargo handling device driven by hydraulic pressure supplied from the hydraulic pressure generator, a power transmission mechanism for transmitting the driving force of the engine from the torque converter to the traveling wheels via the clutch, and an inching In a cargo handling vehicle having a braking mechanism capable of braking a traveling wheel with a clutch connected by a brake pedal,
An inching operation detection unit for detecting depression of the inching brake pedal;
A cargo handling operation detection unit that detects that the cargo handling device is operated on the driving operation side that drives the engine at a high rotation to drive the cargo handling device;
It has a forward / reverse switching valve that can be operated by a forward / reverse operation device to supply, stop, connect, and disconnect hydraulic pressure to the clutch,
The forward / reverse switching valve detects when the cargo handling operation unit has been operated to the drive operation side by the cargo handling operation detection unit, and simultaneously detects the inching brake pedal at the intermediate detection position by the inching operation detection unit. A cargo handling vehicle characterized in that it is configured to stop the supply of the hydraulic pressure for operation and to disengage the clutch. The cargo handling operation detection unit is a pressure switch that detects the hydraulic pressure of the pilot valve operated by the cargo handling device,
The inching operation detection unit is a pressure switch that detects the depression operation based on the fluid pressure discharged from the pilot valve operated by the inching brake pedal, or a position detection switch that detects the depression operation based on the depression position of the inching brake pedal. The cargo handling vehicle according to claim 1. The brake mechanism is driven by hydraulic high-pressure air supplied from a hydraulic drive type or pneumatic pressure accumulator that brakes the traveling wheel by a brake hydraulic pressure supplied from a hydraulic pump or hydraulic pressure accumulator by operating an inching brake pedal. The cargo handling vehicle according to claim 1, wherein the vehicle is an air drive type that brakes a wheel.

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