JPS6018986Y2 - Steering wheel reaction force reduction device at the start of reversing in walking-type mobile agricultural machinery - Google Patents

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention relates to a reaction force reduction device for a mobile agricultural machine such as a small walk-behind tractor when it starts to reverse.

[Conventional technology]

A small walk-behind tractor is equipped with a prime mover, a transmission mechanism that changes the forward movement of the machine using a control lever, and a clutch mechanism that uses a clutch lever to operate the power from the prime mover to the drive wheels on and off. (equipped with two drive wheels), for example, when the prime mover is set to the normal rotation speed, the transmission mechanism is shifted to the reverse position, and the clutch is engaged, the drive wheels will suddenly reverse rotation and the steering wheel will move upwards. A strong reaction force may act, putting the operator in danger.

The danger level is particularly high because the working equipment is attached to the rear of the tractor.

[Purpose of invention]

The present invention was developed in view of the above circumstances, and when the transmission mechanism is shifted to the reverse position, the rotational speed of the prime mover is lowered below the normal rotational speed, and when the clutch is engaged in this state, the rotational speed of the prime mover is reduced. By restoring the rotation speed to the normal rotation speed and allowing the drive wheels to reverse rotation quietly instead of abruptly, the reaction force of the steering wheel when backing up a walk-behind mobile agricultural machine is reduced, allowing for safe maneuvering. The object of the present invention is to provide a steering wheel reaction force reducing device that can prevent accidents from occurring.

〔Example〕

Hereinafter, one embodiment of the present invention will be specifically described with reference to the drawings.

In FIG. 1, reference numeral 1 denotes the body of a small walking-type tractor supported by drive wheels 2 on the left side.
is installed.

Reference numeral 5 denotes a rotary tiller connected to the rear end of the machine body 1, and the rotary tiller 5 receives power from the prime mover 3 to perform rotary tillage work.

The handle 4 includes a clutch lever 6 of a clutch mechanism that connects and connects the rotational power from the prime mover 3 to the drive wheels 2 and the rotary tiller 5, and a shift lever 7 of a transmission mechanism that switches the drive wheels 2 between forward and backward movement. , and an accelerator lever 8 for controlling the rotational speed of the prime mover 3.

In FIGS. 2 and 3, the symbol SW1 is turned on when the shift lever 7 of the transmission mechanism is shifted to the reverse position;
This is a permanent switch that is turned off when the clutch lever 6 is shifted to a position other than the reverse position, and the switch indicated by SW2 is turned off when the clutch lever 6 is in the engaged position, and turned off when it is in the disengaged position. It is a normally closed type that operates so that it is turned on.

Both switches SW1 and SW2 use the battery of a small tractor or a lighting coil as a power source A, and form a series electric circuit with the solenoid SQL.

As shown in FIG. 3, the tip of 5QL-a, which is the operating piece of the solenoid SQL, is connected to the throttle valve lever 9 of the carburetor of the prime mover 3 via a wire 10, and is connected to the switches SW1 and SW2. turns on and solenoid S
When QL is energized, it is energized, attracts the actuating piece SQL-a, and rotates the throttle valve lever 9 of the lowering device to the low speed side.
When the rotation speed is reduced to approximately 1/2 of the normal rotation speed and one or both switches SW1 and SW2 are turned off, the power is cut off and the solenoid SQL is demagnetized, and the actuating piece 5
QL-a is now free.

Further, the throttle valve lever 9 and the slot arm 1 of the carburetor are
1 is connected via springs 14, 15 so as to be interlocked with a lever 13 supported by a pin 12, and when the actuating piece 5QL-a becomes free, the springs 14, 15
The actuating piece 5QL-a is returned to its original position (normal rotational speed) by the action of .

Further, a fly ball 16 provided on the output shaft of the prime mover 3 is connected to the lever 13, and is configured to accelerate and decelerate according to the load of the drive wheel 2 and the rotary tiller 5.

In a device having such a configuration, a small tractor is usually used by adjusting the rotational speed of the prime mover 3 to approximately the normal rotational speed using the slot lever 8.

For example, when performing tillage work, shift the speed change lever 7 to the forward position, set the rotary tiller 5 to the drive side using an operating device (not shown), and then operate the clutch lever 6 to the connecting position. The rotary tiller 5- performs tilling work while being moved forward by the drive wheels 2.

At this time, the switch SW1 remains off, so the solenoid SQL is not energized, and the prime mover 3 does not rotate at bottom speed.

On the other hand, when reversing a small tractor, the vehicle is stopped, the clutch lever 6 is in the off position, and the switch SW2 is in the on state. When the gear shift lever 7 is shifted to the reverse position, the switch SW1 is turned on. Then, the solenoid SQL is energized and excited, and the actuating piece 5QL-a is attracted.

As a result, the throttle valve lever 9 of the carburetor is throttled and the prime mover 3
The rotation speed drops to the normal rotation speed of about 172, and then when the clutch lever 6 is moved to the connecting side, switch SW2
is turned off, solenoid SQL is demagnetized and actuating piece 5
QL-a becomes free, and by the action of the spring 14.15, the operating piece 5QL-a returns to its original position, the throttle valve lever 9 of the carburetor returns to its original position, and the motor 3 gradually returns to normal operation from low speed rotation. The drive wheels 2 are rotated to smoothly move backward without rapidly reversing the driving wheels 2.

Therefore, the backward operation can be performed safely without applying a strong impact force that pushes the bundle 4 in the Lh direction.

In addition, in the above embodiment, by appropriately adjusting the amount of movement of the actuating piece 5QL-a, it is possible to prevent the engine from stalling when the rotation speed of the prime mover 3 is low.
Although this example shows the case of two wheels, it can be implemented in the same way not only for one wheel but also for a diesel engine as well as a gasoline or oil engine.

[Effect of idea]

As explained above, according to the device of the present invention, when the walking-type mobile agricultural machine backs up, the rotational speed of the prime mover is always lower than the normal rotational speed, and then shifts to the normal rotational speed. By reducing the reaction force applied to the bundle at the start of reversing, the bundle can be retracted smoothly and safely, which has the effect of preventing accidents.

[Brief explanation of the drawing]

FIG. 1 is a side view of a small walking tractor equipped with the device of the present invention, and FIG. 2 is an electric circuit diagram used in the device of the present invention.

Claims (1)

[Scope of utility model registration request] The above-mentioned walk-behind mobile agricultural machine is equipped with a prime mover and is equipped with a transmission mechanism that switches the moving backwards and forwards of the machine body using a control lever, and a clutch mechanism that operates on and off the transmission of power from the prime mover to the drive wheels using a clutch lever. A first switch provided in the transmission mechanism and turned on when the operating lever is shifted to a reverse position and turned off when shifted to a position other than the reverse position, and a first switch provided in the clutch mechanism and turned off when the clutch lever is moved to a connected position; a second switch that is turned on when the switch is in the off position; A steering wheel reaction force reduction device for a walk-behind mobile agricultural machine at the start of reversing, characterized in that it is provided with a renoid that operates to bring the rotational speed to a normal rotational speed.