Engine-powered industrial vehicles

Abstract

To provide an engine type industrial vehicle which can surely maintain brake force of an automatic parking brake without against the intention of an operator at the time of inching operation.SOLUTION: In an engine type industrial vehicle which has: a vehicle body; an engine 31 mounted on the vehicle body; an accelerator pedal 43 for increasing / decreasing the rotational speed of the engine 31; an inching pedal 45; an operation lever for operating a work device; a controller 47 for controlling output of the engine 31 on the basis of an operation amount of the accelerator pedal 43 at the time of operation of the operation lever; and an automatic parking brake 55 controlled by the controller 47, generating brake force at the time of vehicle stopping, and releasing brake force by operation of the accelerator pedal 43. The vehicle has an operation switch 58 capable of performing ON / OFF operation, and the controller 47 maintains brake force of the automatic parking brake 55 when the operation switch 58 is turned ON at the time of operation of the inching pedal 45 and the accelerator pedal 43.SELECTED DRAWING: Figure 3

Description

Technical Field

[0001] This invention relates to an engine-type industrial vehicle having an engine as a traveling drive source mounted on a vehicle body.

Background Art

[0002] As a conventional technology related to an engine-type industrial vehicle, for example, a creep running control device for an industrial vehicle disclosed in Patent Document 1 is known. Patent Document 1 discloses an engine-type forklift. In the engine-type forklift of Patent Document 1, the output shaft of the engine is connected to a transmission having a torque converter. The transmission is connected to an axle having drive wheels via a differential device. A service brake is provided on the axle. A parking brake is provided on the output shaft of the transmission.

[0003] On the floor of the cab of the engine-type forklift of Patent Document 1, an accelerator pedal, an inching pedal, and a brake pedal are provided. The inching pedal is used to put the clutch in a semi-engaged state (half-clutch state) when performing a very slow running of the forklift while performing a loading and unloading operation. The stepping operation of the brake pedal is independent of the inching pedal, but the stepping operation of the inching pedal is interlocked with the brake pedal halfway. That is, the inching pedal moves (operates) independently of the brake pedal until it reaches the inching position and at the inching position, but after passing the inching position, the brake pedal moves integrally with the inching pedal.

[0004] Incidentally, with engine-powered forklifts, inching operations, which include operating the inching pedal, can be performed either by handling loads without moving the vehicle, or by handling loads while creeping (moving at a very slow speed), depending on the operator's intention. When handling loads without moving the vehicle, the operator fully depresses the inching pedal and operates the accelerator pedal. When handling loads while creeping during inching operations, the operator lightly depresses the inching pedal so as not to depress it beyond a certain amount and operates the accelerator pedal. This type of engine-powered forklift may be equipped with an automatic parking brake that automatically applies braking force when the vehicle is stopped. The braking force of the automatic parking brake is released by depressing the accelerator pedal after the vehicle has stopped. [Prior art documents] [Patent Documents]

[0005] [Patent Document 1] Japanese Patent Publication No. 2001-114084 [Overview of the project] [Problems that the invention aims to solve]

[0006] However, in engine-powered forklifts equipped with automatic parking brakes, pressing the accelerator pedal always releases the braking force of the automatic parking brake. Therefore, even if the operator presses the inching pedal with the intention of only handling loads without moving, if the inching pedal is not pressed deeply enough, the engine-powered forklift will move at a very slow speed contrary to the operator's intention.

[0007] This invention has been made in view of the above-mentioned problems, and the object of this invention is to provide an engine-powered industrial vehicle that can reliably maintain the braking force of the automatic parking brake without going against the operator's intentions during inching operations. [Means for solving the problem]

[0008] To solve the above problems, the present invention provides an engine-powered industrial vehicle comprising: a vehicle body; an engine mounted on the vehicle body; a work device provided at the front of the vehicle body; an accelerator pedal for increasing or decreasing the rotational speed of the engine; an inching pedal operated when the work device is working; an operating lever for operating the work device; a controller for controlling the output of the engine based on the amount of operation of the accelerator pedal when the operating lever is operated; and an automatic parking brake controlled by the controller, which generates a braking force when the vehicle is stopped and releases the braking force when the accelerator pedal is operated, wherein the vehicle has an operating switch that can be operated ON / OFF, and the controller maintains the braking force of the automatic parking brake when the operating switch is ON when the inching pedal and the accelerator pedal are operated.

[0009] In this invention, when the operating switch is turned ON while the inching pedal and accelerator pedal are being operated, the braking force of the automatic parking brake is maintained. In other words, even if the inching pedal is pressed and the accelerator pedal is pressed while the braking force of the automatic parking brake is being applied, the braking force of the automatic parking brake will not be released. Therefore, the braking force of the automatic parking brake can be reliably maintained during inching operations without contradicting the operator's intentions.

[0010] Furthermore, in the above-mentioned engine-driven industrial vehicle, the operating switch may be provided on the operating lever. In this case, since the control switch is located on the control lever, the control switch can be turned ON at the same time as the control lever is operated during inching operations, improving the operability of the forklift operator.

[0011] Furthermore, in the above-mentioned engine-driven industrial vehicle, a service brake that generates braking force while driving may be provided, and the controller may be configured to activate the service brake when the inching pedal is pressed down to a certain amount or more. In this case, the service brake is activated when the inching pedal is pressed beyond a certain amount. For example, if the accelerator pedal is not pressed when the inching pedal is pressed beyond a certain amount, the automatic parking brake and the service brake can simultaneously generate braking force.

[0012] Furthermore, the present invention relates to an engine-powered industrial vehicle comprising: a vehicle body; an engine mounted on the vehicle body; a work device provided at the front of the vehicle body; an accelerator pedal for increasing or decreasing the rotational speed of the engine; an inching pedal operated when the work device is working; a brake pedal operated when driving; an operating lever for operating the work device; a controller for controlling the output of the engine based on the amount of operation of the accelerator pedal when the operating lever is operated; and a service brake that generates braking force when driving by operating the brake pedal, wherein the engine-powered industrial vehicle comprises: a brake actuator controlled by the controller, which generates braking force for stopping as an automatic parking brake in the service brake and releases the braking force for stopping by operating the accelerator pedal; and an operating switch that can be operated ON / OFF, wherein the controller controls the brake actuator to maintain the braking force for stopping of the service brake when the operating switch is ON when the inching pedal and the accelerator pedal are operated.

[0013] In this invention, even if the inching pedal is pressed and the accelerator pedal is pressed while the braking force of the service brake (which functions as an automatic parking brake) is being applied, the braking force of the service brake (which functions as an automatic parking brake) will not be released. Therefore, the braking force of the service brake (which functions as an automatic parking brake) can be reliably maintained during inching operations without contradicting the operator's intentions. Furthermore, by providing a brake actuator, the function of an automatic parking brake can be added to the service brake. For this reason, there is no need to provide a separate automatic parking brake. [Effects of the Invention]

[0014] According to the present invention, it is possible to provide an engine-powered industrial vehicle that can reliably maintain the braking force of the automatic parking brake during inching operations without going against the operator's intentions. [Brief explanation of the drawing]

[0015] [Figure 1] This is a side view of an engine-powered forklift according to the first embodiment. [Figure 2] This is a plan view of an engine-powered forklift according to the first embodiment. [Figure 3] This is a schematic diagram of the engine-powered forklift according to the first embodiment. [Figure 4] This is a flowchart illustrating the control of the automatic braking system when the inching pedal is not fully depressed. [Figure 5] This is a flowchart illustrating the control of the automatic braking system when the inching pedal is pressed deeply. [Figure 6] This is a schematic diagram of an engine-powered forklift according to the second embodiment. [Figure 7] (a) is a longitudinal cross-sectional view of the brake actuator during braking, and (b) is a longitudinal cross-sectional view of the brake actuator when the brakes are released. [Modes for carrying out the invention]

[0016] (First embodiment) Hereinafter, an engine-powered industrial vehicle according to an embodiment of the present invention will be described with reference to the drawings. The engine-powered industrial vehicle of this embodiment is an engine-powered forklift used as a material handling vehicle. The directions "front and back," "left and right," and "up and down" are indicated based on the state in which the forklift operator is seated in the driver's seat and facing the forward direction of the forklift.

[0017] As shown in FIGS. 1 and 2, the forklift 10 includes a cargo handling device 12 as a working device at the front part of the vehicle body 11. A driver's seat 13 is provided near the center of the vehicle body 11. Front wheels 14 are provided at the front part of the vehicle body 11, and rear wheels 15 are provided at the rear part of the vehicle body 11. The front wheels 14 are driving wheels, and the rear wheels 15 are steering wheels. A counterweight 16 is provided at the rear part of the vehicle body 11, and the counterweight 16 is for adjusting the vehicle weight and achieving weight balance in the vehicle body 11. A head guard 17 covering the upper part of the driver's seat 13 is provided on the vehicle body 11.

[0018] The cargo handling device 12 includes a mast 18 having an outer mast 19 and an inner mast 20. A pair of left and right outer masts 19 are provided with a pair of left and right inner masts 20 that can be raised and lowered inside the outer masts 19. The cargo handling device 12 includes a lift bracket 21 that moves up and down along the inner mast 20, and the lift bracket 21 is provided with a pair of left and right forks 22 and a backrest 23. The left and right forks 22 scoop up and support the load. The backrest 23 supports the rear surface of the load supported by the pair of left and right forks 22.

[0019] A tilt cylinder 24 operated by hydraulic oil is installed between the vehicle body 11 and the cargo handling device 12. The cargo handling device 12 tilts in the front-rear direction with the lower end of the cargo handling device 12 as a fulcrum by the operation of the tilt cylinder 24. A lift cylinder 25 operated by supply and discharge of hydraulic oil is provided on the outer mast 19 (see FIG. 1). By the operation of the lift cylinder 25, the inner mast 20 moves up and down inside the outer mast 19, and the lift bracket 21 also moves up and down.

[0020] An instrument panel 26 is located in front of the driver's seat 13. The instrument panel 26 is equipped with a steering column 27 that supports the steering wheel 28. The instrument panel 26 is equipped with a key cylinder (not shown) into which a key is inserted, as well as a lift lever 29 and a tilt lever 30, which are cargo handling levers. The lift lever 29 is an operating lever for raising and lowering the forks 22. The tilt lever 30 is an operating lever for tilting the mast 18 forward and backward. The vehicle body 11 is equipped with an engine 31, and the vehicle body 11 is equipped with an openable engine hood 32 that covers the engine 31. The driver's seat 33 is located on top of the engine hood 32.

[0021] As shown in Figure 3, the output shaft 35 of the engine 31 is connected to a torque converter 36, and the output shaft 37 of the torque converter 36 is connected to a reduction gear 38. The reduction gear 38 has a differential mechanism (not shown) that distributes the rotational force input from the torque converter 36 to the left and right axles 39. The axles 39 are equipped with front wheels 14. A hydraulic oil pump 40 is provided, which is operated by the engine 31. The vehicle body 11 is equipped with a hydraulic oil tank 41 for storing hydraulic oil. The hydraulic oil pump 40 and the torque converter 36 are connected by hydraulic oil piping 42. When the hydraulic oil pump 40 is operated, it draws hydraulic oil from the hydraulic oil tank 41. The hydraulic oil drawn up by the hydraulic oil pump 40 is supplied to the torque converter 36 via the hydraulic oil piping 42. During cargo handling operations, the hydraulic oil drawn up by the hydraulic oil pump 40 is supplied to the lift cylinder 25 and tilt cylinder 24.

[0022] Incidentally, the floor of the driver's seat 13 is equipped with an accelerator pedal 43, a brake pedal 44, and an inching pedal 45. The accelerator pedal 43 is a pedal that increases or decreases the rotational speed of the engine 31. An accelerator sensor 46 is provided to detect the amount of operation by pressing the accelerator pedal 43. The accelerator sensor 46 is connected to a controller 47. The controller 47 is mounted in the vehicle body 11 at a position directly below the driver's seat 33 (see Figure 1). The controller 47 controls various parts of the forklift 10. For example, when the accelerator pedal 43 is pressed, the controller 47 controls the engine 31 according to the amount of operation of the accelerator pedal 43. As shown in Figure 3, the controller 47 that controls various parts of the forklift 10 includes a CPU 48, a memory unit 49 consisting of RAM and ROM, etc.

[0023] The controller 47 may include dedicated hardware, such as an application-specific integrated circuit (ASIC), that performs at least some of the various processes. The controller 47 can be configured as a circuit including one or more processors that operate according to a computer program, one or more dedicated hardware circuits such as ASICs, or a combination thereof. The memory unit 49 stores program code or instructions configured to cause the CPU 48 to perform the processes. The memory unit 49 stores various programs for controlling the various parts of the forklift 10.

[0024] As shown in Figure 3, the brake pedal 44 is a pedal for generating braking force for the service brakes 50 provided on the left and right axles 39. The service brakes 50 are brakes that include a disc plate 51 provided on the axle 39 and a brake plate 52 that clamps the disc plate 51 in conjunction with the brake pedal 44. The forklift 10 is equipped with a brake sensor 53 that detects whether or not the brake pedal 44 is pressed down. The brake sensor 53 is connected to a controller 47. Note that the service brakes 50 may also be drum brakes.

[0025] The inching pedal 45 is operated when moving the forks 22 up and down at a slow speed or when the forks 22 are stationary and the upward speed of the forks 22 is increased. The forklift 10 is equipped with an inching sensor 54 that detects the amount of movement of the inching pedal 45. The inching sensor 54 is connected to a controller 47. The controller 47 recognizes that the inching pedal 45 is pressed shallowly if it is pressed less than a certain amount, and that it is pressed deeply if it is pressed more than a certain amount. When the inching pedal 45 is fully pressed, the inching pedal 45 is reliably pressed more than a certain amount. When the inching pedal 45 is pressed deeply, the controller 47 activates the service brake 50 and generates braking force.

[0026] As shown in Figure 3, an automatic parking brake 55 is provided at the rear of the reduction gear 38. The automatic parking brake 55 is a known wet multi-plate brake that automatically generates braking force on the output shaft 37 when the forklift 10 stops. A hydraulic fluid pipe 56 is provided connecting the automatic parking brake 55 and the torque converter 36. The hydraulic fluid pipe 56 is equipped with an electromagnetic valve 57 that opens and closes the hydraulic fluid pipe 56. The electromagnetic valve 57 is controlled by a controller 47. When the electromagnetic valve 57 is closed, the automatic parking brake 55 generates and maintains braking force. On the other hand, when the electromagnetic valve 57 is opened, hydraulic fluid is supplied to the automatic parking brake 55, and the braking force is released by the hydraulic pressure. The controller 47 controls the electromagnetic valve 57 to open when the accelerator pedal 43 is operated.

[0027] In this embodiment, the lift lever 29 is equipped with an operating switch 58. The operating switch 58 is connected to a controller 47, and when the operator presses the operating switch 58, an ON signal is transmitted to the controller 47. When the operating switch 58 is not pressed, an OFF signal is transmitted to the controller 47. When the operating switch 58 is pressed, the controller 47 controls the electromagnetic valve 57 so that the braking force of the automatic parking brake 55 is not released even when the accelerator pedal 43 is operated.

[0028] Specifically, the controller 47 controls the automatic parking brake 55 during inching operations according to a series of steps shown in Figures 4 and 5. First, we will explain the control when the inching pedal 45 is not pressed down by more than a certain amount during inching operations, and the pressing is shallow. When raising and lowering the forks 22 while driving at a slow speed, the operator presses the inching pedal 45 shallowly so as not to press it down by more than a certain amount. Note that inching operation refers to the operation in which the inching pedal 45 is pressed down.

[0029] As shown in Figure 4, when the forklift 10 stops, the automatic parking brake 55 is activated (step S101). The activation of the automatic parking brake 55 generates braking force. Next, when the operator performs an inching operation during cargo handling, the inching pedal 45 is pressed down. Since the operator intends to raise and lower the forks 22 while moving at a slow speed, the operator presses the inching pedal 45 shallowly without pressing it down beyond a certain amount. Therefore, the controller 47 recognizes that the inching pedal 45 has been pressed shallowly (step S102). Since the operator presses the accelerator pedal 43 after pressing the inching pedal 45, the controller 47 recognizes that the accelerator pedal 43 has been pressed down (step S103).

[0030] Next, the controller 47 determines whether the operation switch 58 is ON or OFF (step S104). If it is determined that the operation switch 58 is ON, the controller 47 maintains the closed state of the electromagnetic valve 57. As a result, the automatic parking brake 55 remains activated (step S105). Next, the controller 47 determines whether the operation switch 58 is OFF or OFF (step S106). If it is determined that the operation switch 58 is OFF, the controller 47 opens the electromagnetic valve 57. As a result, the braking force of the automatic parking brake 55 is released (step S107). With the braking force of the automatic parking brake 55 released, the forklift 10 moves at a slow speed (creep).

[0031] Furthermore, in step S104, if it is determined that the operation switch 58 is not ON, the controller 47 opens the electromagnetic valve 57. As a result, the braking force of the automatic parking brake 55 is released. Also, in step S106, if it is determined that the operation switch 58 is not OFF, the controller 47 maintains the closed state of the electromagnetic valve 57.

[0032] Next, we will explain the control when the inching pedal 45 is pressed down by a certain amount or more during inching operations. When the forklift 10 is stopped and the forks 22 are to be raised and lowered quickly, the operator presses the inching pedal 45 down by a certain amount or more. As shown in Figure 5, when the forklift 10 stops, the automatic parking brake 55 is activated (step S201). Braking force is generated when the automatic parking brake 55 is activated. Next, when the operator performs an inching operation during cargo handling, the inching pedal 45 is pressed down. Since the operator intends to stop the forklift 10 and quickly raise and lower the forks 22, the operator presses the inching pedal 45 down by a certain amount or more. For this reason, the controller 47 recognizes that the inching pedal 45 has been pressed down deeply (step S202). Since the operator presses the accelerator pedal 43 after pressing the inching pedal 45, the controller 47 recognizes that the accelerator pedal 43 has been pressed down (step S203).

[0033] Next, the controller 47 determines whether the operation switch 58 is ON or OFF (step S204). If it is determined that the operation switch 58 is ON, the controller 47 maintains the closed state of the electromagnetic valve 57. Therefore, the automatic parking brake 55 remains activated (step S205). Next, the controller 47 determines whether the operation switch 58 is OFF or OFF (step S206). If it is determined that the operation switch 58 is OFF, the controller 47 opens the electromagnetic valve 57. Therefore, the braking force of the automatic parking brake 55 is released (step S207). Although the braking force of the automatic parking brake 55 is released, the controller 47 generates braking force of the service brake 50 because the inching pedal 45 is deeply depressed, and the forklift 10 stops and does not move. In other words, the controller 47 controls the system to activate the service brake 50 when the inching pedal 45 is depressed by a certain amount or more.

[0034] Furthermore, in step S204, if it is determined that the operation switch 58 is not ON, the controller 47 opens the electromagnetic valve 57. As a result, the braking force of the automatic parking brake 55 is released. Also, in step S206, if it is determined that the operation switch 58 is not OFF, the controller 47 maintains the closed state of the electromagnetic valve 57.

[0035] The forklift 10 of this embodiment provides the following effects. (1) When the operating switch 58 is turned ON while the inching pedal 45 and accelerator pedal 43 are being operated, the braking force of the automatic parking brake 55 is maintained. In other words, even if the inching pedal 45 is pressed and the accelerator pedal 43 is pressed while the braking force of the automatic parking brake 55 is being applied, the braking force of the automatic parking brake 55 will not be released. Therefore, the braking force of the automatic parking brake 55 can be reliably maintained during inching operations without going against the operator's intentions.

[0036] (2) Since the operation switch 58 is provided on the lift lever 29 which is used as a cargo handling lever, the operation switch 58 can be turned ON at the same time as the operation of the lift lever 29 used during inching operations, improving the operability of the forklift 10 operator.

[0037] (3) The forklift 10 is equipped with a service brake 50 that generates braking force while in motion, and the controller 47 controls the service brake 50 to activate when the amount of inching pedal 45 is greater than or equal to a threshold. Therefore, when the inching pedal 45 is pressed down by a certain amount or more, the service brake 50 is activated, so for example, if the accelerator pedal 43 is not pressed when the inching pedal 45 is pressed down by a certain amount or more, the automatic parking brake 55 and the service brake 50 can generate braking force simultaneously.

[0038] (4) When the inching pedal 45 and accelerator pedal 43 are operated, the controller 47 maintains the braking force of the automatic parking brake 55 when the operation switch 58 is ON. Therefore, if the operation switch 58 is turned ON, the braking force of the automatic parking brake 55 will not necessarily be released even if the accelerator pedal 43 is pressed during inching. Thus, even if the operator presses the inching pedal 45 with the intention of only handling cargo without moving, and the inching pedal 45 is not pressed down beyond a certain amount, by turning the operation switch 58 ON, the forklift 10 will not move at a slow speed against the operator's intention.

[0039] (Second embodiment) Next, a forklift according to the second embodiment will be described. This embodiment differs from the first embodiment in that the service brake also functions as an automatic parking brake. In this embodiment, the same configuration as in the first embodiment will be described by referring to the description of the first embodiment and will use the same reference numerals.

[0040] As shown in Figure 6, the forklift 60 of this embodiment has a brake actuator 61 for an automatic parking brake so as to add the function of an automatic parking brake to the service brake 50. As shown in Figures 7(a) and 7(b), the brake actuator 61 has a cylindrical body portion 62, a movable portion 63 that can move back and forth relative to the body portion 62, a hydraulic fluid chamber 64 formed in the body portion 62, and a coil spring 65 that biases the movable portion 63.

[0041] As shown in Figures 7(a) and 7(b), one end of the movable part 63 protrudes from the main body 62, and one end of the parking brake cable 66 is connected to the protruding end of the movable part 63. One end of the parking brake cable 66 is connected to the brake plate 52 of the service brake 50. The coil spring 65 is a biasing member that biases the movable part 63 in the direction of pulling it towards the main body 62. The hydraulic fluid chamber 64 is a space into which hydraulic fluid is introduced. When hydraulic fluid is supplied to the hydraulic fluid chamber 64, the movable part 63 moves in the direction of protruding against the coil spring 65 by the hydraulic pressure.

[0042] As shown in Figure 6, the hydraulic fluid chamber 64 is connected to the hydraulic fluid pump 40 via the hydraulic fluid piping 67. The brake actuator 61 is equipped with an electromagnetic valve 68 that opens and closes the hydraulic fluid piping 67. The electromagnetic valve 68 is controlled by the controller 47. The controller 47 controls the service brake 50 to function as an automatic parking brake when the forklift 60 stops. Specifically, the controller 47 closes the electromagnetic valve 68, causing the parking brake cable 66 to be pulled to the brake actuator 61, and generating braking force for the service brake 50.

[0043] The controller 47 controls the operation of the accelerator pedal 43 to open the electromagnetic valve 68, and the parking brake cable 66 is loosened, releasing the braking force of the service brake 50, which acts as an automatic parking brake. If the operation switch 58 is turned ON, the braking force of the service brake 50, which acts as an automatic parking brake, is not released even if the accelerator pedal 43 is pressed during inching operations. When the forklift 10 is in motion, the electromagnetic valve 68 is open. As a result, hydraulic fluid is supplied to the brake actuator 61, and no braking force is generated by the brake actuator 61 or the service brake 50; instead, braking force is generated by pressing the brake pedal 44. When the electromagnetic valve 68 is closed from the open state, the hydraulic fluid in the hydraulic fluid chamber 64 is released from residual pressure simultaneously with the closing of the electromagnetic valve 68 and is recovered into the hydraulic fluid tank 41.

[0044] According to this embodiment, even if the inching pedal 45 is pressed and the accelerator pedal 43 is pressed while the braking force of the service brake 50, which functions as an automatic parking brake, is being generated, the braking force of the service brake 50 will not be released. Therefore, the braking force of the service brake 50, which functions as an automatic parking brake, can be reliably maintained during inching operations without contradicting the operator's intentions. Furthermore, by providing the brake actuator 61, the function of an automatic parking brake can be added to the service brake 50. For this reason, there is no need to provide a separate automatic parking brake.

[0045] The present invention is not limited to the embodiments described above, and various modifications are possible within the scope of the invention. For example, the following modifications may be made.

[0046] ○ In the above embodiment, an example was described in which the operating switch is provided on the operating lever, but it is not limited to this. The operating switch may be provided, for example, on the steering wheel, or on an object that is within the range of operation of the operator in the driver's seat. ○ In the above embodiment, the operating switch is provided on the lift lever, which is an operating lever, but it is not limited to this. The operating switch may be provided on, for example, the tilt lever, which is an operating lever, or on a cargo handling lever other than the lift lever and tilt lever, such as the side shift lever. Furthermore, the operating switch may be provided on all cargo handling levers, or it may be provided only on specific cargo handling levers. ○ In the above embodiment, the controller was controlled to activate the service brake as an automatic parking brake when the inching pedal was depressed by a certain amount or more, but it is not limited to this. The controller may, for example, be controlled not to activate the service brake as an automatic parking brake even when the inching pedal is depressed by a certain amount or more. ○ In the first embodiment described above, a wet brake was used as an example of an automatic parking brake, but it is not limited to this. The automatic parking brake may be a drum brake, for example, and the type of brake is not particularly limited. Furthermore, the position of the automatic parking brake is not particularly limited as long as it is in a position where braking is possible. ○ In the above embodiment, the service brake is a disc brake, but it is not limited to this. The service brake may be a drum brake, for example, and the type of brake is not particularly limited. ○ In the above embodiment, a brake sensor and an inching sensor are provided, but the system is not limited thereto. The brake sensor and inching sensor may be omitted. For example, the inching pedal and the brake pedal may be mechanically linked, and the brake pedal may be mechanically connected to the service brake. ○ In the above embodiment, an engine-powered forklift was used as an example of an engine-powered industrial vehicle, but the invention is not limited to this. An engine-powered industrial vehicle may be a material handling vehicle such as a forklift, or, for example, an engine-powered construction vehicle equipped with a work device, such as a wheel loader equipped with a bucket arm as a work device. [Explanation of Symbols]

[0047] 10.60 Engine-powered forklift (engine-powered industrial vehicle) 11 Car body 12. Cargo handling equipment (working equipment) 13. Driver's seat 18 Mast 22 Forks 29. Lift lever (operating lever) 30 Tilt lever 31 Engine 33 Driver's seat 36 Torque Converter 38 Reducer 39 axles 40. Hydraulic oil pump 43 Accelerator pedal 44 Brake pedal 45-inch pedal 47 Controllers 50 Service brake 55 Automatic parking brake 57, 68 Electromagnetic valves 58 Operating switches 61 Brake Actuator 66 Parking brake cable 67 Hydraulic oil piping 68 Electromagnetic valve

Claims

1. The car body and, The engine mounted on the aforementioned vehicle body, A work device provided at the front of the vehicle body, An accelerator pedal for increasing or decreasing the rotational speed of the aforementioned engine, An inching pedal operated during operation with the aforementioned work device, An operating lever for operating the aforementioned work device, A controller that controls the output of the engine based on the amount of operation of the accelerator pedal when the operating lever is operated, In an engine-powered industrial vehicle having an automatic parking brake controlled by the aforementioned controller, which generates braking force when the vehicle is stopped and releases the braking force by operating the accelerator pedal, It has an operating switch that allows for ON / OFF operation. The controller is characterized in that when the operating switch is ON during operation of the inching pedal and the accelerator pedal, it maintains the braking force of the automatic parking brake in an engine-powered industrial vehicle.

2. The engine-driven industrial vehicle according to claim 1, characterized in that the operating switch is provided on the operating lever.

3. It is equipped with a service brake that generates braking force while driving, The engine-powered industrial vehicle according to claim 1 or 2, characterized in that the controller controls the operation of the service brake when the inching pedal is pressed down by a certain amount or more.

4. The car body and, The engine mounted on the aforementioned vehicle body, A work device provided at the front of the vehicle body, An accelerator pedal for increasing or decreasing the rotational speed of the aforementioned engine, An inching pedal operated during operation with the aforementioned work device, The brake pedal, which is operated while driving, An operating lever for operating the aforementioned work device, A controller that controls the output of the engine based on the amount of operation of the accelerator pedal when the operating lever is operated, In an engine-powered industrial vehicle having a service brake that generates braking force during driving by operating the brake pedal, A brake actuator controlled by the controller generates a braking force for stopping, acting as an automatic parking brake, in the service brake, and releases the braking force for stopping by operating the accelerator pedal, It has an operating switch that allows ON / OFF operation, The controller is characterized in that when the operating switch is ON during operation of the inching pedal and the accelerator pedal, it controls the brake actuator to maintain the braking force of the service brake when the vehicle is stopped.

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