JP2002362338A - Braking device for lift truck - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a braking device for a lift truck capable of reducing a work load of an operator. SOLUTION: In the braking device for the lift truck provided with a brake pedal 23 for operating a deadman system brake in a cab ridden by the operator, an assisting means 40 is provided for energizing the brake pedal 23 in a stepped direction when the brake pedal 23 is stepped into a brake releasing position. The assisting means 4 can be operated only when an accelerator operating tool 14 of the lift truck is operated.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a lift truck braking device.

[0002]

2. Description of the Related Art Generally, a lift truck is provided with a traveling device for traveling the vehicle body and a braking device for stopping the traveling of the vehicle body. As the braking device, a mechanical braking device occupies the mainstream. A method of electrically braking the traveling motor of the device may be used together.

A mechanical braking device is configured to press a wear-resistant member such as a brake shoe or a brake pad against a rotating body interlocked with a traveling motor, a driving wheel, or the like, and brake the rotating body by friction. As a method of pressing the member, a method using an electric device such as an electromagnet and a method using a mechanical mechanism are generally used, but a method using a hydraulic device can also be adopted.

In any case, the brake device is provided with an operating tool for the operator to perform a brake operation, that is, a brake operating tool. In the brake device of the lift truck, the operator drives while walking near the vehicle body. Except for the model, a brake pedal is provided as the brake operation tool.

[0005] By the way, lift trucks on which the operator gets on the vehicle are classified into two types, one in which the operator sits in the driver's seat and operates, and the other type in which the operator stands in the driver's cab. In the latter case, the brake pedal is used. When the brake pedal is depressed, the brake action is released, and the brake is activated if the brake pedal is depressed shallower or the brake pedal is not depressed. ing.

[0006]

In a lift truck employing this deadman type braking device, it is necessary to continuously depress the brake pedal to maintain a state in which the braking action is released in order to travel.

However, in this deadman type braking device, the operator loosens the brake pedal,
In order to make the braking device respond swiftly when the brake is released, a spring is provided which constantly urges the brake pedal to the maximum braking position where the braking force is maximized.

[0008] Therefore, during traveling, the operator must keep pressing the brake pedal against this spring, so that the operator is physically imposed on the operator. In particular, the weight of the labor load becomes a problem for operators with weak operating forces, such as female operators, elderly operators, and operators with physical dysfunction, which have increased in recent years.

Of course, in the case of a braking device in which the wear-resistant member is driven by an electric device such as an electromagnet or a hydraulic device, the operating force of the brake pedal is reduced by setting the elasticity of the spring for urging the brake pedal in the opening direction to be small. However, in a braking device in which the anti-friction member is driven by a brake pedal via a mechanical mechanism,
Since it is necessary to press the wear-resistant member against the rotating body with a predetermined pressure or more, the operating force of the brake pedal cannot be weakened to a certain level or more.

SUMMARY OF THE INVENTION An object of the present invention is to solve the problems of the prior art and to provide a lift truck braking device capable of reducing the workload of an operator.

[0011]

SUMMARY OF THE INVENTION The present invention attains the above object in a braking apparatus for a lift truck having a brake pedal provided on a cab on which an operator gets on to perform a deadman type braking operation. For,
When the brake pedal is depressed to the brake release position, a technical means is provided in which assisting means is provided for urging the brake pedal in the depressing direction.

Accordingly, if the brake pedal is depressed to the brake release position, the urging force of the assisting device opposes a part of the elasticity of the spring that urges the brake pedal in the braking action direction, so that the operator has to The effect is obtained that the force required to keep the brake pedal depressed to the brake release position is reduced.

In the present invention, the assisting means urges the brake pedal in the stepping-down direction when the brake pedal is located at the brake release position. In order to respond, the urging force of this assisting means must be set weaker than the spring that urges the brake pedal in the opening direction. However, when the brake pedal is not depressed to the brake release position, the assisting means does not bias the brake pedal, so that the assisting means does not hinder the brake operation.

The running of the lift truck includes power running in which the running motor is energized to drive the driving wheels by the running motor, and coasting in which the vehicle including the load is driven by the inertia of the vehicle body. Since an operation is required, it is preferable to reduce the resistance to the braking operation. In addition, since the running by the coasting operation is relatively short, the labor for continuously depressing the brake pedal is hardly a problem.

Also, while the vehicle is stopped, the accelerator means is not operated, and the brake pedal is positioned at the maximum braking position to maintain the vehicle body in a stopped state.
The above-mentioned assisting means is not used.

Therefore, in the present invention, the assisting means is made operable only when the accelerator means of the lift truck is operated, and when the assisting means is unnecessary, for example, monitoring of the position of a brake pedal is performed. It is recommended to reduce wasteful energy consumption.

The assisting means of the present invention includes those having a brake release detecting means for detecting that the brake pedal is depressed to the brake releasing position and those not having the brake releasing detector. It is advantageous to provide this brake release detecting means in order to perform on / off control depending on whether or not it is located.

The brake release detecting means may be driven by a brake pedal of the braking device or a mechanical mechanism component linked thereto to detect that the brake pedal is at the brake release position. .

For example, a switch such as a contact switch, a knife switch, a non-contact switch such as a proximity switch typified by a microswitch, or a sensor such as a pressure sensor, a photosensor, an acoustic sensor, or an ultrasonic sensor is used as brake release detecting means. However, it is also possible to use a measuring means such as a potentiometer or a rotary encoder as the brake release detecting means.

When the anti-friction member of the braking device is driven by an electric actuator, the brake release detecting means can be constituted by an energization detecting means for detecting the energization or the like of the electric actuator. When the member is driven by a hydraulic actuator, a position change of a hydraulic pressure sensor that detects a supply pressure to a hydraulic actuator that drives the wear-resistant member and a control valve that controls the supply and discharge of pressure oil to the hydraulic actuator is detected. The brake release detecting means can be constituted by a position sensor that performs the operation, an energization sensor that detects energization to an electromagnetic control valve that controls the supply and discharge of the hydraulic oil to and from the hydraulic actuator, and the like.

The assisting means of the present invention needs to include an urging means for urging the brake pedal located at the brake release position in the depressing direction.
Although it is possible to use a spring, rotary drive means such as an electric motor, a rotary solenoid, and a hydraulic motor, linear drive means such as a linear motor, a linear solenoid, an electric cylinder, and a hydraulic cylinder, and suction means such as a magnet including an electromagnet In addition, it is advantageous to use an adsorbing means because the structure can be simplified.

In the case where the assisting means of the present invention includes the brake release detecting means and the urging means, when the brake release detecting means detects that the brake pedal is depressed to the brake release position, It is necessary to provide an assisting control means for operating the urging means.As the assisting control means, there is provided a microcomputer, or a switch circuit which is opened and closed depending on whether or not the brake release detecting means is energized. What is constituted may be used.

In the present invention, as a method of enabling the assisting means only when the accelerator means of the lift truck is operated, a method for detecting whether or not the accelerator means is operated, and only when the accelerator operation is detected, There is a method of enabling the assisting means, and there are a method of turning on / off the assisting control means of the assisting means, and a method of turning on / off the energization or supply of the pressure oil to the urging means.

In order to carry out these methods, anyway, an accelerator operation detecting means for detecting the presence or absence of an accelerator operation is provided. As the accelerator operation detecting means, an energizing detecting means for detecting the presence or absence of energization to the traveling motor may be employed. When detecting the operation of the accelerator operating means, for example, a microcomputer of the assisting means is activated. The assist control means configured as described above, an assist control means in which a switch circuit opened / closed by the presence or absence of energization of the brake release detection means and a switch circuit opened / closed by the presence or absence of energization of the traveling operation detection means are connected in series. Should be adopted.

The traveling operation detecting means only needs to be configured to be able to detect that the traveling operation means is traveling by being driven by an accelerator operating tool or a component linked thereto.

For example, a switch such as a contact switch, a knife switch, a non-contact switch such as a proximity switch typified by a microswitch, or a sensor such as a pressure sensor, a photosensor, an acoustic sensor, or an ultrasonic sensor is used as brake release detecting means. However, it is also possible to use a measuring means such as a potentiometer or a rotary encoder as the brake release detecting means.

According to the present invention, as another method for enabling the assisting means to be operated only when the accelerator means of the lift truck is operated, the assisting means may be operated only when the accelerator means is operated by the brake pedal or the brake pedal. There is a method in which the brake pedal is urged to be connected to a mechanical mechanism component to be actuated, and is arranged at a position separated from the brake pedal or a mechanical mechanism component associated therewith when the accelerator means is not operated.

As is apparent from the above description, according to the present invention, not only the brake device in which the wear-resistant member of the braking device is operated by the brake pedal via the mechanical mechanism, but also the above-mentioned wear-resistant member is driven by an electric device or a hydraulic device. In such a case, the elasticity of the spring for urging the brake pedal to the maximum braking position can be freely determined.

Next, the present invention relates to a brake apparatus for a lift truck having a brake pedal provided on a cab on which an operator gets on to perform a deadman type brake operation. Technical means is employed in which a locking means for locking the pedal to the brake release position by friction is provided.

According to this, when the brake pedal is located at the brake release position, the friction of the locking means acts as a resistance against the urging force of the spring for urging the brake pedal in the direction of the brake operation, and the brake pedal is released. The burden on the operator who continues to step on the brake release position is reduced.

The method of locking the brake pedal at the brake release position includes a method of directly locking the brake pedal and a method of locking a mechanical mechanism component linked to the brake pedal.

Further, according to the present invention, there is provided a braking apparatus for a lift truck having a brake pedal provided on a driver's cab on which an operator gets on to perform a deadman type braking operation. Technical means is adopted in which positioning means for positioning the pedal at the brake release position is provided.

According to this, when the brake pedal located at the brake release position is moved to the brake application position, the force required to release the positioning operation of the positioning means urges the brake pedal in the brake application direction. The resistance to the elasticity of the spring is reduced, and the burden on the operator who continues to depress the brake pedal to the brake release position is reduced.

In this case, the method of positioning the brake pedal at the brake release position includes a method of directly positioning the brake pedal and a method of positioning a mechanical mechanism component linked with the brake pedal.

[0035]

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a perspective view of a lift truck braking device according to an embodiment of the present invention.
It is as follows.

FIG. 1 is a circuit block diagram of assisting means provided in a lift truck braking device according to one embodiment of the present invention, and FIG. 2 is a perspective view of the lift truck. This lift truck is called a reach-type forklift. For example, as shown in FIG. 2, the vehicle body 1 of the lift truck includes a frame 2, a mast 3, a backrest 4, and a fork 5. A cockpit 6 into which an operator rides is provided at the right rear.

The frame 2 is composed of a rear frame 2a and a left and right 1 which are provided at an appropriate distance in front of the rear frame 2a.
And a pair of front frames 2b.
Is a quadrilateral bottom frame 2c with left and right sides cornered at the rear end in plan view, left and right side plates 2d and 2e raised on each of the left and right sides, the bottom frame 2c and the left and right sides A connection plate 2f for connecting the front and rear intermediate portions of the face plates 2d and 2e. The cockpit 6 has a front surface defined by the connection plate 2f and a battery storage portion, and a right surface defined by the right side plate 2e. The left side of the cockpit 6 is divided into a power room by a first side panel 7 fixed to the connecting plate 2f and the bottom frame 2c of the frame 2, and a driver's cab 8 stretched on the lower surface of the cockpit 6. It is defined as the space below it. Further, the rear and upper surfaces of the cockpit 6 are continuously open.

An operation panel 10 is provided on the front side of the cockpit 6 to cover the upper surface of the battery storage section. The operation panel 10 is operated to extend and retract the mast 3 to move the backrest 4 and the fork 5 up and down. A lifting lever 11, a tilt lever 12 for operating the backrest 4 and the fork 5 to tilt, a reach lever 13 for operating the mast 3, the backrest 4 and the fork 5 forward and backward, and the lift An accelerator operation tool (generally referred to as an accelerator lever) 14 for operating the truck back and forth is provided in order from left to right.

The rear side of the power room is covered with a second side panel 9 which can be opened and closed, and the top surface is covered with a top panel 15. A steering wheel 1 for controlling the traveling direction is provided above the top panel 15.
6 are provided.

A traveling motor, a hydraulic power unit, and the like are housed in the power room, and drive wheels 17 interlocked with the traveling motor via a reduction gear project downward from the lower surface of the opened power room. To roll on the ground.

A support wheel 18 is rotatably supported by each front frame 2b, and a bottom frame 2c is provided below the driver's cab 8.
Is provided with a universal wheel 19 supported by the user.

The accelerator operating tool 14 is provided so as to be tiltable back and forth about a neutral position which stands vertically with respect to the operation panel 10, for example. When the vehicle stops, the vehicle body 1 stops, and when the vehicle is tilted forward from the neutral position, the traveling motor rotates in the forward direction and the vehicle body 1 advances. When the vehicle body 1 leans backward from the neutral position, the traveling motor rotates in the reverse direction and the vehicle body 1 rotates. Retreats. The lift truck is provided with a braking device for braking the traveling of the vehicle body 1.

FIG. 3 is a side view of the brake device for the lift truck, FIG. 4 is a rear view of the brake device, and FIG.
FIG. 2 is a plan view of the braking device. These FIGS. 3 and 4
As shown in FIG.
9, a pair of upper and lower brake pads 22 to be brought into contact with and separated from the upper and lower surfaces of the brake disk 21, near the driver's cab 8 at the far left of the cockpit 6. A brake pedal 23 is provided, and a mechanical mechanism 24 for interlocking the brake pad 22 with the brake pedal 23 is provided.

As shown in FIGS. 3 and 5, a bracket 25 is fixed to the upper portion of the traveling motor 19, and a pair of holder arms 26, which are vertically opened and closed with the brake disc 21 interposed therebetween, One end of each arm 27 is pivotally supported, and the brake pads 22 are fixed to the surfaces of the holder arms 26 and 27 facing the brake disc 21, respectively.

As shown in FIG. 3, bolts 28 whose heads are received on the upper surface of the upper holder arm 26 are inserted through the free ends of the upper and lower holder arms 26, 27, respectively. A spring 30 composed of a compression coil spring is inserted between a spring seat 27 and a spring seat 29 supported by the bolt 28 below the spring 27. The spring 30 always closes both holder arms 26 and 27, and the brake The pad 22 is urged in the direction in which the pad 22 is pressed against both surfaces of the brake disc 21 (the direction in which the brake acts).

A brake release cam 3 such as an elliptical cam, an egg-shaped cam, a triangular cam, an S-shaped or a Z-shaped cam is provided on the upper portion of the traveling motor 19 via a bracket 25.
2 is rotatably supported between the free ends of the two holder arms 26 and 27. By rotating the brake release cam 32, the two holder arms 2 are opposed to the spring 30.
When the distance between the free ends 6 and 27 is increased, both brake pads 22 are separated from the brake disc 21 and the braking action is released.

An adjustable screw 33 for receiving the brake release cam 32 is provided at a free end of each of the holder arms 26 and 27. By adjusting the position at which the adjust screw 33 receives the brake release cam 32, the position of the adjustable screw 33 is adjusted. The distance between the disk 21 and the pad 22 when the brake is released is adjusted.

As shown in FIGS. 3 to 5, the support frame 2g raised in the power room near the first side panel 7 is fixed to the bottom frame 2c. As described later, the brake pedal 23 is supported so as to be rotatable between a brake release position in which the front end portion is centered, for example, in a horizontal position, and a brake operation position in which the rear end portion jumps up.

The mechanical mechanism 24 includes a brake pedal 23
It is sufficient if the brake pad 22 is configured to be interlocked with the first. In this embodiment, as described below, the first
Rod 34, bell crank 35, and second rod 3
6 and a lever 37. First, the first rod 34 is provided with a length adjusting means 38 as required, and a lower end thereof is connected to, for example, an intermediate portion of the brake pedal 23 in the front-rear direction.

The bell crank 35 is connected to the connecting plate 2f.
A rotating shaft 35a rotatably supported by a rearward arm 35b and an upward arm 35b, which swing directions are different by about 90 °.
c, the upper end of the first rod 34 is connected to the free end of the rearward arm 35b.
The front end of the second rod 36 is connected to the free end of 5c. The second rod 36 is provided with a length adjusting means 39 if necessary, and the rear end of the second rod 36 is provided with the brake release cam 3.
It is connected to a free end of the lever 37 fixed to the second rotation center shaft 32a.

According to the braking device 20, when the operator steps on the brake pedal 23 deeper than a certain amount toward the brake release position, the first rod 34 is pulled down, and the second rod is pulled down via the bell crank 35. Rod 36
Is pulled forward, the brake release cam 32 is driven via the lever 37 to separate the brake pad 22 from the brake disk 21, and the braking action is released.

When the operator releases the brake pedal 23 or depresses his / her foot from the brake pedal 23, the spring 30 pushes the brake release cam 32 in a direction to reduce the cam lift, and the brake release cam 32 When the brake pedal 23 rotates beyond a certain position on the brake application position side from the brake release position in conjunction with the above, the brake pad 22 is pressed against the brake disk 21 by the spring 32, and the brake operation is effective.

When the operator only steps on the brake pedal 23 but does not step on it, or when the operator retreats from the brake pedal 23, the spring 32 pushes the brake pedal 23 back to the braking position. It is.

Therefore, according to the braking device 20, the vehicle 1
In order to make the vehicle travel, it is necessary for the operator to apply force to the foot and depress the brake pedal 32 more than a certain amount to release the braking action, and it is necessary to keep the depressed state continuously during traveling.

The braking device 20 according to this embodiment is
When the brake pedal 23 is depressed during traveling, the brake pedal 23 is urged in the depressing direction to provide an assisting means 40 for assisting the operator to depress. As shown in FIG.
When the vehicle is running and the brake pedal 23 is depressed to the brake release position, the brake pedal 2
Brake release detecting means 41 for detecting that the brake pedal 23 is located at the brake release position so as to urge the brake pedal 3 in the stepping direction, and a rotary solenoid which can urge the brake pedal 23 in the stepping direction. Means 42, a driver 43 for turning on and off the driving power supply of the urging means 42, and turning on the driver 43 when the brake release detecting means 41 detects that the brake pedal 23 is depressed to the brake release position. An assisting control means 44 comprising a microcomputer (microcomputer) for switching off the driver 43 at the time of switching or non-detection is provided.

As shown in FIG. 3, in this embodiment, the brake release detecting means 41 is constituted by a microswitch, and when the brake pedal 23 is at the brake release position, for example, a drive piece 45 fixed to the bell crank 35 is used. When the brake pedal 32 is released and turned on, and the brake pedal 32 is rotated from the brake release position in the braking action direction, it is driven by the drive piece 45 and turned off.

When the brake release detecting means 41 is turned on, the assisting control means 44 switches the driver 43 on to supply a drive current to the urging means 42, and when the brake release detecting means 41 is turned off, The assisting control means 44 switches off the driver 43 to cut off the driving current of the urging means 42.

The urging means 42 is supported by the support frame 2g, and its rotating shaft 42a is mounted on the brake pedal 23.
Is fixed at the front end. Thereby, the brake pedal 2
3 is supported by the support frame 2g so that it can rotate between the brake release position and the maximum braking position together with the rotation shaft 42a about the rotation shaft 42a.

FIG. 6 is a cross-sectional view schematically showing the structure of a rotary solenoid constituting the urging means 42. The urging means 42 includes a casing 42b fixed to the support frame 2g and a casing 42b. The above rotating shaft 4
A rotor 42c rotatably supported within a predetermined angle range in the casing 42b through the rotor 2c;
An electromagnet 42d for magnetically attracting 2c to one end of its rotation stroke. When the urging means 42 is energized, the rotor 42c is attracted by the electromagnet 42d in a direction opposite to the urging force of the spring 30, so that the brake pedal 23
In the stepping direction, and when no power is supplied, the rotor 42c
Is released from the electromagnetic attraction of the electromagnet 42c, so that the brake pedal 23 can rotate freely within a predetermined range together with the rotation shaft 42a. As described above, when the brake pedal 23 is urged in the stepping direction by the assisting means 40 when the brake pedal 23 is located at the brake release position, the operating force of the operator continuing to depress the brake pedal 23 by the amount of the urging force is reduced. And thus the operator's workload is reduced.

Further, even a weak operator such as an elderly person, a woman, or a physically handicapped person can easily continue to depress the brake pedal 23 to the brake release position.

By the way, as shown in FIG. 1, in this embodiment, it is assumed that the assisting device 40 is operating the accelerator operating tool 14, that is, tilting forward or backward from the neutral position. An accelerator operation detecting means 46 for detecting is provided. This accelerator operation detecting means 46
To be able to detect that the accelerator operating tool 14 is being operated, for example, when the accelerator operating tool 14 is positioned at the neutral position, the accelerator operating tool 14 is driven and turned on by the accelerator operating tool 14, and the accelerator operating tool 14 is turned on. When it is located at a position other than the neutral position, it is constituted by a microswitch which is released from the accelerator operation tool 14 and turned off. When the accelerator operation detecting means 46 is on, the assist control means 44
And the brake release detecting means 41 are connected to the power supply 47 so that the assisting means 40 can be operated. That is, when the brake pedal 23 is depressed to the brake release position during the accelerator operation, the assisting means 40 is operated, and the brake pedal 23 is urged in the depressing direction. On the other hand, when the accelerator operation detecting means 46 is off, the assist control means 44 is cut off from the power supply 47 to invalidate the brake release detecting means 41, and the brake release detecting means 41 is cut off from the power supply 47. Operation becomes impossible. Thus, the assist means 4 for the operation of the brake pedal 23 during coasting is provided.
The resistance of 0 is eliminated, and delicate brake operation is facilitated, and wasteful power consumption is reduced.

Of course, when the accelerator operation detecting means 46 does not detect the accelerator operation, the assist control means 44
It is not essential to the present invention to cut off the brake release detecting means 41 from the power supply 47. The assist control means 44 and the brake release detecting means 41 are connected to the power supply 47 regardless of the presence or absence of the accelerator operation. Is also good. Further, in this embodiment, the assisting control means 44 is constituted by a microcomputer. Alternatively, for example, as shown in an electric circuit diagram of FIG. The assist control means 44 may be constituted by a switch circuit interposed in the circuit.

Auxiliary means 44 comprising this switch circuit
The brake release detection means 41 and the accelerator operation detection means 46 are interposed in series. The relay switch having a relay coil interposed in the power supply circuit of the brake release detection means 41, and the accelerator operation detection means A configuration may be such that a relay switch having a relay coil interposed in the power supply circuit of the detection means 46 is interposed in series with the power supply circuit of the urging means 42.

FIG. 8 is a side view of a lift truck braking device according to another embodiment of the present invention. As shown in FIG. 8, in this embodiment, the urging means 42 is connected to the first rod 34. Is supported by the connecting plate 2f.

When the brake pedal 23 is depressed to the brake release position, a rack tooth row is provided at an intermediate height of the first rod 34 which moves toward the connecting plate 2f so as to face the connecting plate 2f. A gear 42f is fixed to the rotating shaft 42a of the urging means 42 and is engaged with and disengaged from the rack teeth 42e. In this example,
When the brake pedal 23 is depressed to the brake release position, the rack tooth row 42e moves to the connecting plate 2g side and the gear 42
If the urging means 42 is turned on at this time, the brake pedal 23 is urged in the stepping direction via the first rod 34.

On the other hand, when the brake pedal 23 moves from the brake release position to the brake operation side, the rack teeth 42e are separated from the gear 42f, and the urging means 42 urges the brake pedal 23 in the depressing direction. You can't do that.

In the case of this embodiment, the urging means 42
May be always energized. However, since the energizing means 42 is energized only when the brake pedal 23 is at the brake release position during the accelerator operation as in the previous example, wasteful power consumption is reduced. Can be reduced.

Other configurations, operations and effects of this embodiment are the same as those of the previous embodiment.

In each of the above embodiments, a technical means is employed in which the brake pedal 23 or a mechanical mechanism component linked thereto is urged in the stepping direction by the urging means 42 comprising a rotary solenoid, which is a kind of rotary drive means. are doing. In order to achieve the purpose of reducing the workload of the operator, it is most preferable to positively bias the brake pedal 23 in the stepping direction. For example, the brake pedal 23 depressed to the brake release position or the brake pedal 23 A different pressure-resistant member may be pressed with an appropriate pressure against the mechanical mechanism component so as to generate a resistance against the urging force of the spring 30 due to a frictional force. The above object can also be achieved by positioning the brake pedal 23 or a mechanical mechanism component interlocked with the brake pedal 23 at the brake release position using the positioning means.

[0070]

As described above, according to the present invention, when the brake pedal is depressed to the brake release position, the assisting means for urging the brake pedal in the depressing direction is provided. If the brake pedal is depressed to the brake release position, the urging force of the assisting device opposes a part of the elasticity of the spring that urges the brake pedal in the braking action direction, so that the operator continues to depress the brake pedal to the brake release position. The effect of this is that the force required for braking is reduced, and as a result, the workload of the operator is reduced, and even an operator, such as the elderly, a woman, or a physically handicapped person, who has a weak brake operating force can press the brake pedal to the brake release position. The effect that it becomes easy to continue is obtained.

Further, since the present invention is provided with locking means for locking the brake pedal to the brake release position by friction, the frictional force of the locking means causes a resistance to the spring which urges the brake pedal in the braking action direction. The effect is obtained that the force required for the operator to continue to depress the brake pedal to the brake release position is reduced,
As a result, the workload of the operator is reduced, the elderly,
An effect is obtained that even an operator having a weak brake operation force, such as a woman or a physically handicapped person, can easily keep pressing the brake pedal to the brake release position.

Further, since the present invention is provided with positioning means for positioning the brake pedal at the brake release position, the force required to release the positioning means exerts a resistance against a spring which urges the brake pedal in the direction in which the brake is applied. This has the effect of reducing the force required for the operator to continue to depress the brake pedal to the brake release position, thereby reducing the operator's workload and reducing the brakes for elderly people, women, persons with physical disabilities, etc. An effect is obtained that even an operator with a weak operating force can easily keep pressing the brake pedal to the brake release position.

[Brief description of the drawings]

FIG. 1 is a circuit block diagram of the present invention.

FIG. 2 is a perspective view of the present invention.

FIG. 3 is a side view of the present invention.

FIG. 4 is a rear view of the present invention.

FIG. 5 is a plan view of the present invention.

FIG. 6 is a cross-sectional view of the present invention.

FIG. 7 is an electric circuit diagram of the present invention.

FIG. 8 is a side view of the present invention.

[Explanation of symbols]

 Reference Signs List 8 cab 14 accelerator operation tool 23 brake pedal 40 assisting means 41 brake release detecting means 42 urging means 44 assisting control means 46 accelerator operation detecting means

Claims (8)

[Claims] 1. A brake device for a lift truck having a brake pedal provided on a cab on which an operator gets on to perform a deadman type brake operation, wherein the brake pedal is depressed to a brake release position. A lift truck braking device, further comprising assisting means for urging a brake pedal in a stepping direction. 2. The braking apparatus for a lift truck according to claim 1, wherein the assisting means can be operated only when the accelerator means of the lift truck is operated. 3. The assisting means includes: brake release detecting means for detecting that the brake pedal is depressed to a brake release position; urging means for urging the brake pedal in a depressing direction; 3. An assist control means for activating said urging means when it is detected by said means that said brake pedal is depressed to a brake release position.
The braking device for a lift truck described in the above. 4. A braking apparatus for a lift truck according to claim 1, wherein said assisting means directly biases said brake pedal. 5. The braking device for a lift truck according to claim 1, wherein the assisting means urges the brake pedal via a component interlocked with the brake pedal. 6. The assisting means is mechanically linked to the braking device when the brake pedal is depressed to a brake release position, and when the brake pedal is not depressed to the brake release position, the assisting means is activated by the brake. The braking device for a lift truck according to claim 1, wherein the braking device is disengaged from the device. 7. A brake device for a lift truck including a brake pedal provided on a driver's cab on which an operator gets on to perform a deadman type brake operation, wherein the brake pedal is frictionally locked to a brake release position by friction. A braking device for a lift truck, comprising a stopping means. 8. A brake device for a lift truck having a brake pedal provided for performing a deadman type brake operation on a driver's cab on which an operator gets on, comprising positioning means for positioning the brake pedal at a brake release position. A braking device for a lift truck.