JPH0585396A - Reversing alarm device of cargo handling car - Google Patents

Abstract

PURPOSE:To provide a reversing alarm device in a skid steering type cargo handling car, which can send a reversing alarm signal surely before the start of the reversing motion of the car. CONSTITUTION:A loose joint 20 provided on a steering rod 12 which connects a steering lever 13 with a hydraulic pump 3 has so-called back-lash, and reversing operation of the steering lever 13 is transmitted to a running hydraulic pump system with a time lag corresponding to the back-lash. A reversing alarm switch 26 is driven by means of the steering rod 12, which is located at the nearer position to the steering lever 13 than the loose joint 20, and as the result, the reversing alarm signal can be sent before the start of the reversing motion of the car.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a skid steer-type cargo handling vehicle warning device for backward movement.

[0002]

2. Description of the Related Art In a skid steer type cargo handling vehicle, for example, a pair of left and right steering levers are used to individually adjust the swash plate tilt angles of a pair of variable displacement hydraulic pumps to adjust the amount of discharged oil and the direction of discharge. The rotational speed and the rotational direction of a pair of hydraulic motors for wheel drive are changed to control the traveling speed and forward and backward movement of the vehicle. One example thereof is a front view of the driver's seat of the skid steerer and traveling. The hydraulic system is shown in FIGS.

The traveling operation of the loader will be described in more detail with reference to FIG. 7. A pair of tandem variable displacement pumps 3 directly connected to the output shaft of the engine 4 are connected to a pair of hydraulic models through a high pressure pipe 6. -The hydraulic motor 7 is driven individually.
Drives tires 9 on each side through a chain type transmission mechanism 8. The pump 3 has a plurality of cylinders (not shown) axially formed on the same circumference in a cylinder block (not shown) that is directly connected to the output shaft of the engine 4 and rotates, and extends from each cylinder. A piston (not shown) is supported by a swash plate (not shown) via a joint (not shown). By controlling the tilt angle of the swash plate, the discharge amount and discharge direction of oil can be controlled, whereby the rotation speed and rotation direction of the hydraulic motor 7 can be adjusted, and the rotation speed and rotation direction of the tire 9 can be changed.

The steering device of this loader will be described with reference to FIGS. When the steering lever 13 rotates about the steering pin 14, the working end of the steering lever 13 drives the trunnion lever 11 via the steering rod 12, and the trunnion lever 11 is connected to the trunnion pin 10 by the pump 3 The swash plate (not shown) is tilted to control the discharge oil amount and the discharge direction. The other end of the trunnion lever 11 is a support plate for fixing the pump housing through a spring holder 15.
A coil spring built in the spring holder 15 is urged to hold the trunnion lever 11 in the neutral position. In FIG. 9, only the left steering lever device is shown. Next, the backward warning switch will be described with reference to FIG.

The switch 16 is a limit switch having a roller 17 as an operating element and is a trunnion lever-1.
The trunnion lever 11 is closed in the rearward movement of the trunnion lever 11 to issue a backward warning to turn on the backward warning buzzer and the backward warning lamp.

[0006]

The reverse warning switch 16 described above is operated by the trunnion lever 11 connected to the steering lever 13, but a reverse warning is generated due to play inside the switch 16 or a displacement of the mounting position of the switch 16. There is a possibility that the backward warning light cannot be turned on promptly due to the delay in issuing the warning.

SUMMARY OF THE INVENTION The present invention has been made in view of the above problems, and it is an object of the present invention to provide a reverse warning device capable of reliably issuing a reverse warning before starting the reverse of a skid steer type cargo handling vehicle. It should be an issue.

[0008]

SUMMARY OF THE INVENTION A reverse warning device for a cargo handling vehicle according to the present invention comprises a pair of left and right wheel drives for adjusting the discharge direction of a traveling hydraulic pump system by a transmission system connected to a pair of left and right steering levers. Change the rotation direction of the hydraulic motor of
A skid steer type cargo handling vehicle that switches between forward and backward movement of the vehicle, a floating portion interposed in the transmission system for invalidating the initial reverse operation of the steering lever, and a reverse warning for activation by the initial reverse operation. And a switch.

[0009]

The action and the effect of the invention: The floating portion provided in the transmission system mechanism connecting the steering lever and the traveling hydraulic pump system (for example, the swash plate of the hydraulic pump) has a so-called play, and the steering lever is initially retracted. Is transmitted to the traveling hydraulic pump system by being invalidated by the amount of this play, and as a result, the oil discharge for reversing the vehicle is delayed by the amount of play of the floating portion.

The reverse warning switch is driven by the initial reverse operation of the steering lever, so that the operation of the switch precedes the idle part by the amount of play of the idle part. Therefore, according to the device of the present invention, in the skid steer type cargo handling vehicle, the reverse warning switch can reliably issue the reverse warning prior to the actual start of reverse, so that the reverse warning light is turned on or the reverse warning buzzer is issued. It is possible to obtain an excellent effect that the drive of − can always be performed before the actual backward movement.

[0011]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Preferred embodiments of the present invention will be described below with reference to FIGS.
Will be described. FIG. 1 is a plan view showing a steering device of a loader of this embodiment, and FIG. 2 is a side view thereof. The pair of left and right steering levers 13 is the steering pin 1.
The steering lever 13 is rotatably held by the vehicle body 4, and the tip ends (not shown) of both steering levers 13 extend upward from the left and right sides of the driver's seat. The working end 13a (see FIG. 2) of the steering lever 13 is connected to the steering rod 1 by a joint 19.
2 is linked to the front end of the steering rod 12
The rear end is linked by a joint 18 to one end 11a of the trunnion lever 11. Steering rod 1
A floating joint (a floating portion referred to in the present invention) 20 described later is provided in the center portion of 2. More specifically, the steering rod 12 is screwed into each end of the joints 18 and 19, and the effective length of the steering rod 12 can be adjusted by loosening the lock nut and rotating the steering rod 12 integrated with the floating joint 20. It is possible. The trunnion lever 11 is fixed to a trunnion pin 10 extending from the swash plate (not shown) of the axial piston type hydraulic pump 3 to the left and right of the pump, and the turning of the steering lever 13 is performed by a joint 19 and a floating joint 20. Integrated steering rod 12, joint 18, trunnion lever 11, trunnion pin 10
The swash plate is tilted in sequence to sequentially control the rotation speed and the rotation direction of the left and right tires 9, whereby the traveling and turning of the loader are performed.

On the other hand, the other end of the trunnion lever 11 is connected to a support plate 31 fixed to the pump housing through a spring holder 15, and a coil spring built in the spring holder 15 neutralizes the trunnion lever 11, that is, the swash plate. It is biased to hold in position. As shown in FIG. 5, this coil spring has a characteristic of preventing the rotation of the trunnion lever 11 when the operating force of the steering rod 12 is in the range of -f to f.

Incidentally, in FIG. 2, the steering lever on the left side is shown.
Only the system is shown. Next, the floating joint 20 will be described with reference to FIGS. 3 and 4. The floating joint 20 has a case composed of a shallow-bottom cylinder 21 and a deep-bottom cylinder 22, and the cylinder 22 is screwed into the cylinder 21 to form a case.
A closed cylindrical working chamber S is formed inside the chamber. A cylindrical slider 23 is slidably accommodated in the working chamber S, and a rear end portion of the front steering rod 12 penetrates a hole at the center of the bottom portion of the cylinder 21 and is welded to a front end surface of the slider 23. There is. On the other hand, the front end of the rear steering rod 12 is welded to the rear end surface of the cylinder 22. A stopper 25 projects rearward from around the rear end surface 24 of the slider 23, and when the vehicle is stopped (the neutral position of the steering lever 13) and when the vehicle is moving forward, the tip of the stopper 25 is a small distance from the bottom of the cylinder 22 that faces it ( 5mm here)
They are facing each other apart (see FIG. 3). Further, a limit switch 26 is attached to the working chamber S, and an operator 27 of the limit switch 26 has a rear end surface 24 of the slider 23.
Is in contact with.

When the steering lever 13 is in the neutral position, the front end of the slider 23 is in contact with the bottom of the cylinder 21, so that when the steering lever 13 is tilted forward from the neutral position, it is fixed to the front steering rod 12. The slider 23 moves the rear steering rod 12 forward via the cylinders 21 and 22, thereby tilting the swash plate in the forward direction via the trunnion lever 11 and the trunnion pin 10, so that the pump 3 moves forward. Discharge the running oil.

Conversely, when the left and right steering levers 13 are tilted backward from their neutral positions, the slider 23 fixed to the front steering rod 12 moves backward in the working chamber S by a distance d, and as a result, the slider 23. The rear end face 24 presses the operating element 27 to close the internal normally open contact of the limit switch 26, and the two normally open contacts of the left and right limit switches 26 are connected in series to extend from a captyre wire (not shown). Turns on the buzzer and the backward warning light for warning the backward warning provided on the vehicle body. Since the operating resistance of the operator 27 is much lighter than the neutral maintaining force of the coil spring for maintaining the neutral in the spring holder 15, the trunnion lever is used.
11 remains stationary, the swashplate tilt angle does not change, and the vehicle does not begin to retreat.

When the left and right steering levers 13 are further tilted backward, the slider 23 moves backward in the working chamber S, the stopper 25 abuts against the bottom of the cylinder 22, and then the slider 23.
Through the cylinder 22 to the rear steering rod 12,
The swash plate is tilted in the backward direction via the trunnion lever 11 and the trunnion pin 10, and as a result, the hydraulic motor for traveling is used.
(Not shown) rotates in the reverse direction, and the vehicle starts to move backward.

In this way, the start of the vehicle retreating can be delayed from the warning of the backward warning by the amount that the floating joint 20 has the play d, and the running safety is improved. Further, even if an error in mounting the limit switch 26 or the like occurs, it can be absorbed by the play d, so that there is an advantage that the conventional precise mounting of the limit switch 26 is not required.

Further, in this embodiment, the limit switch 2
Since 6 is built in the floating joint 20,
By mounting the floating joint 20, the limit switch 26 can be automatically mounted at a predetermined position, which simplifies the assembly. In the above embodiment, the floating joint 2
Although the limit switch 26 is built in 0, the limit switch for the backward warning may be operated by the steering rod 12 or the joint 19 on the front side of the floating joint 20.

Instead of the limit switch 26, it is possible to use another type of switch such as a photo interrupter.

[Brief description of drawings]

FIG. 1 is a plan view showing a steering device of this embodiment,

FIG. 2 is a side view of FIG.

FIG. 3 is a cross-sectional view of a floating joint at neutral and forward movements,

FIG. 4 is a cross-sectional view of the floating joint when retracted,

FIG. 5 is a characteristic diagram of a coil spring for maintaining a trunnion lever-neutral.

FIG. 6 is a front view near the driver's seat of a conventional loader,

7 is a block diagram showing a traveling hydraulic system of the loader of FIG. 6;

8 is a plan view showing the steering device of the loader of FIG. 6;

9 is a side view showing the steering device of the loader of FIG. 6,

FIG. 10 is a plan view showing a conventional backward warning device,

FIG. 11 is a plan view showing a main part (switch part) of a conventional backward warning device,

[Explanation of symbols]

 3 hydraulic pump (travel hydraulic pump system), 13 steering lever 13, 12 steering rod (transmission system), 18 joint (transmission system), 19 joint (transmission system), 11 trunnion lever (transmission system), 20 floating joint (Floating part), 26 limit switch (reverse warning switch),

Claims (1)

[Claims] 1. A transmission system connected to a pair of left and right steering levers adjusts the discharge direction of a traveling hydraulic pump system to change the rotational directions of a pair of hydraulic motors for driving left and right wheels.
A skid steer type cargo handling vehicle that switches between forward and backward travel of the vehicle, a floating portion that is interposed in the transmission system to invalidate the initial reverse operation of the steering lever, and a warning switch that is activated by the initial reverse operation. A reverse warning device for a cargo handling vehicle, comprising: