JP2605523B2 - Reverse warning device for cargo handling vehicles - Google Patents

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 warning device for warning that a cargo vehicle has retreated.

[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 individually adjusts a swash plate inclination angle of a pair of variable displacement hydraulic pumps to adjust a discharge oil amount and a discharge direction. FIG. 7 illustrates a front view of a driver seat portion of a skid steer loader and a traveling hydraulic system as an example of which changes the rotation speed and rotation direction of a pair of drive hydraulic motors to control the traveling speed and forward / backward traveling of the vehicle. Shown in FIG.

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

[0004] A steering device of the loader will be described with reference to FIGS. 9 and 10. 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
Tilts a swash plate (not shown) of the pump 3 connected to the trunnion pin 10 to control the discharge oil amount and the discharge direction. 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 urges the trunnion lever 11 to hold the trunnion lever 11 at a neutral position. FIG. 10 shows only the left steering lever device. 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 operator, and is a trunnion lever-1.
It is disposed on the vehicle body in the vicinity of 1 and closes when the trunnion lever 11 is moved backward, issues a reverse warning and turns on the reverse warning buzzer and the reverse warning light.

[0006]

The above-described reverse warning switch 16 is operated by a trunnion lever 11 connected to the steering lever 13, but the reverse warning is provided by play inside the switch 16 or a displacement of the mounting position of the switch 16. May be delayed, and the reverse warning light may not be turned on quickly.

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 issuing a reverse warning without fail in a skid steer type cargo-handling vehicle before the vehicle reverse starts. Should be an issue to be addressed.

[0008]

SUMMARY OF THE INVENTION A reversing warning device for a cargo handling vehicle according to the present invention adjusts the discharge direction of a traveling hydraulic pump system by a transmission system connected to a pair of left and right steering levers to drive a pair of left and right wheels. Change the rotation direction of the hydraulic motor
A floating portion mounted on a skid steer type cargo handling vehicle for switching the vehicle between forward and backward, interposed in the transmission system and invalidating an initial retreat operation of the steering lever, and a reversal warning activated by the initial retreat operation. And a switch.

[0009]

The idler interposed in the transmission system for 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 this play, and as a result, the oil discharge for retreating the vehicle is delayed by the play of the idler.

The reverse warning switch is driven by the initial reverse operation of the steering lever, so that the operation of the switch precedes the idler by the play of the idler. 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 before the actual reverse starts, so that the reverse warning light is turned on and the reverse warning buzzer is activated. The excellent effect that the negative drive can always be performed before the actual reverse operation can be achieved.

[0011]

1 and 2 show a preferred embodiment of the present invention.
This will be described with reference to FIG. FIG. 1 is a plan view showing a steering apparatus of a loader according to the present embodiment, and FIG. 2 is a side view thereof. The pair of left and right steering levers 13 is a steering pin 1
4, the steering levers 13 are rotatably held on the vehicle body, and the front 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 and the steering rod 12
Is connected to one end 11a of the trunnion lever 11 by a joint 18. Steering rod 1
A floating joint (a floating portion in the present invention) 20, which will be described later, is provided at a central portion of 2. More specifically, the steering rod 12 is screwed into one end of each 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. The rotation of the steering lever 13 is controlled by a joint 19 and a floating joint 20. , Steering rod 12, joint 18, trunnion lever 11, trunnion pin 10
, The swash plate is tilted sequentially to individually control the rotational speed and the rotational direction of the left and right tires 9 so that the loader travels and turns.

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. Biased to hold in position. As shown in FIG. 5, the 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.

In FIG. 2, the left steering lever is provided.
Only the system is shown. Next, the floating joint 20 will be described with reference to FIGS. This floating joint 20 has a case composed of a shallow bottom cylinder 21 and a deep bottom cylinder 22.
A working chamber S having a closed cylindrical shape is formed inside the casing. A cylindrical slider 23 is slidably accommodated in the working chamber S, and a rear end of the front steering rod 12 is welded to a front end face of the slider 23 through a hole at the bottom center of the cylinder 21. I have. 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 protrudes rearward from around the rear end surface 24 of the slider 23, and when the vehicle stops (the neutral position of the steering lever 13) and moves forward, the tip of the stopper 25 has a small distance (from the bottom of the cylinder 22 opposed thereto). (Here 5mm)
They face apart (see FIG. 3). A limit switch 26 is attached to the working chamber S, and an operator 27 of the limit switch 26 is
Is in contact with

At the neutral position of the steering lever 13, 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 steering rod 12 on the rear side forward through the cylinders 21 and 22, thereby inclining the swash plate in the forward direction via the trunnion lever 11 and the trunnion pin 10, and as a result, the pump 3 moves forward. Discharges traveling oil.

Conversely, when the left and right steering levers 13 are tilted rearward 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. The rear end face 24 presses the operating element 27 to close the internal normally open contact of the limit switch 26, and connects the two internal normally open contacts of the left and right limit switches 26 in series to extend a captire wire (not shown). Turns on a buzzer for issuing a reverse warning and a reverse warning light provided on the vehicle body. Since the operating resistance of the operating element 27 is very light as compared with the neutral maintaining force of the coil spring for maintaining the neutral in the spring holder 15, the trunnion lever is operated.
11 remains stationary, the swashplate tilt angle does not change, and the vehicle does not start retreating.

When the left and right steering levers 13 are further tilted rearward, the slider 23 moves backward in the working chamber S, and the stopper 25 abuts against the bottom of the cylinder 22.
Is the steering rod 12 on the rear side via the cylinder 22,
The swash plate is inclined in the retreating direction via the trunnion lever 11 and the trunnion pin 10, and as a result, the hydraulic motor
(Not shown) reversely rotates, and the vehicle starts to retreat.

In this manner, the start of retreating the vehicle can be delayed from the issuance of the retraction warning by an amount corresponding to the play d of the floating joint 20, and the traveling safety is improved. Further, even if an error occurs in mounting the limit switch 26, the play d can absorb the error, so that there is an advantage that it is not necessary to mount the limit switch 26 precisely as in the related art.

Further, in this embodiment, the limit switch 2
6 is built into the floating joint 20,
By assembling the floating joint 20, the limit switch 26 can be automatically attached to a predetermined position, thereby simplifying the assembly. In the above embodiment, the floating joint 2
Although the limit switch 26 is built in 0, the limit switch for retreat 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, another type of switch such as a photo interrupter can be used.

[Brief description of the drawings]

FIG. 1 is a plan view showing a steering device according to an embodiment.

FIG. 2 is a side view of FIG. 1;

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

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

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

FIG. 6 is a front view showing the vicinity of a driver's seat of a conventional loader.

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

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

FIG. 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 (power transmission system), 18 joint (power transmission system), 19 joint (power transmission system), 11 trunnion lever (power transmission system), 20 floating joint (Floating part), 26 Limit switch (backward switch),

Claims (1)

(57) [Claims] A driving system connected to a pair of left and right steering levers to adjust a discharge direction of a traveling hydraulic pump system to change a rotation direction of a pair of left and right wheel driving hydraulic motors;
A floating portion mounted on a skid steer type cargo handling vehicle for switching the vehicle forward and backward, interposed in the transmission system and invalidating an initial retreat operation of the steering lever, and a warning switch activated by the initial retreat operation. And a retreat warning device for a cargo-handling vehicle.