JPS6387901A - Rising and falling control mechanism of agricultural tractor - Google Patents

Abstract

(57) [Abstract] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to an elevation control mechanism for an agricultural tractor, and more particularly to an elevation control mechanism mechanically configured to control the elevation of a ground work device.

[Conventional technology]

Conventionally, in plowing work performed by connecting a rotary tiller to an agricultural tractor, the ground level of the rotary tiller is detected from the amount of rocking of the rear cover provided on the rotary tiller, and the rocking posture of the rear cover is determined in a predetermined manner. Feedback control is performed on hydraulic valves for lifting and lowering to maintain the same state (for example, Japanese Utility Model Application Publication No. 10329/1983).

[Problem that the invention seeks to solve]

In addition, conventional lift control mechanisms are equipped with a so-called position lever to arbitrarily raise and lower ground work devices such as rotary tillers, and are also provided with a so-called position lever that is in contact with the feedback control system to prevent it from interfering with the feedback control system during automatic plowing depth control. Due to flexibility in structure, etc., the operating system of hydraulic valves is
Usually, a spring is provided that sets the biasing force direction in the direction of lowering the ground work equipment and returns the hydraulic valve.

Therefore, when the ground work device is arbitrarily raised or lowered, the biasing force from the spring may act on the position lever, so there is room for improvement.

An object of the present invention is to obtain a structure that reduces the biasing force acting on the position lifting system from the return operation spring without causing any hindrance to the operation of the automatic lifting system of ground work equipment through rational modification. be.

[Means for solving problems]

The features of the present invention include a member that is connected to a hydraulic pulp that controls the elevation of the ground work device and that swings and deflects due to the feedback operation force generated in response to changes in the ground level of the ground work device, and A spring for operating the hydraulic pulp is provided between a swinging member that is linked to the level setting operating lever and swings and deviates substantially coaxially with the above-mentioned member, and its operation and effects are as follows. is as follows.

[For production]

If the above features are configured as shown in FIGS. 1 and 2, for example, the position lever (7), which is an example of an operating lever for setting the level relative to the vehicle body of the ground work device (4), is moved (lower) during automatic plowing depth control. By setting the swing member (23) to the Kl) position, there is a large distance between the swing member (23) and the member (20), and the swing member (23) is attached to the operating arm (21) that operates the hydraulic pulp (9). The load of the return spring (24) that exerts a biasing force in the direction of bringing the and member (20) closer together acts, and when the ground work device (4) is arbitrarily raised or lowered, the position lever is By simply operating (7), the swinging member (23) and the member (20) come into close proximity, and the return spring (20) acts on the position lever (7).
24) becomes extremely low.

〔Effect of the invention〕

Therefore, by a relatively simple modification of installing a spring between two members installed on the coaxial core, the biasing force of the spring works well during automatic elevation control, and the load from the return spring is reduced during position control. This resulted in a structure that allows for lifting and lowering operations with light operating force.

〔Example〕

Embodiments of the present invention will be described below based on the drawings.

As shown in Figure 4, a pair of left and right lift arms (2), (
The three-point link mechanism (3) is raised and lowered by the operation of (2).
) to connect a rotary tiller (4), which is an example of a ground work device.

The lift arms (2), (2) are operated by a hydraulic cylinder (5) installed in the transmission case (1), and a ground work device is installed on the side of the driver's seat (6) on the agricultural tractor. A position lever (7) as an example of an operating lever for setting the level relative to the vehicle body, and a tilling depth setting lever (8) for automatic tilling depth control of the low tillage device (4)
and these two levers (7) and (8)
is interlocked and connected to a hydraulic valve (9) built into the transmission case (1) through the following structure.

In other words, as shown in Figures 1 to 3, hydraulic pulp (
9) is the operating position (U) for raising the lift arm (2), (2), the operating position (D) for lowering it, and the neutral position W
(N) Each of the spools (9s) is equipped with an operable spool (9s), and this spool (9s) is connected to an arm (10) that is pivotably supported horizontally around an axis on the left and right side walls of the mission case (1). , (10) It is pivotally connected to the center portion of a scale-shaped arm (11) whose both ends are supported by the respective swinging ends so as to be swingable about the vertical axis.

Further, the support shaft (12) of the left arm (10) (right side in FIG. 2) and the left lift arm (2) are interlocked and connected via a feedback iron (13), and the right arm (10) The support shaft (14) and the position lever (
7), both levers of the plowing depth setting lever (8) are linked by the following structure.

As shown in Fig. 2, a horizontal pivot shaft (15) is provided on the mission case (1), and this pivot shaft (15)
From the mission case (1) side, the first boss (1
6), three cylindrical bodies, a second boss (17) and a third boss (18), are fitted on the outside, and the first boss (16) receives the feed hack operation force from the rotary tiller (4). A feedback arm (19) that acts and a member (20) that swings and deflects together with the first boss (16) by the feedback operation force are provided, and this member (20) and the support shaft (
The operating arm (21) provided on the rond (22)
are interlocked and connected via.

A plowing depth setting lever (8) is connected and fixed to the second boss (17), and an arm portion (8a) formed by bending the end of the lever (8) is provided. ) is connected and fixed with a position lever (7) and a swinging member (23) that can be operated in contact with the member (20), and furthermore, between the member (20) and the swinging member (23) there is a A helical spring (24) is provided that urges both members toward each other.

In addition, the feedback system for automatic tillage depth control includes a link (25) for taking out the rocking movement of the rear cover (4a) of the rotary tillage device (4), and a wire connected to the link (25), as shown in Fig. 1. (26), the outer part (26) of the wire (26)
a), the first swinging arm (27) supporting the wire (26
), a second swinging arm (28) to which the inner part (26b) of
29), a rond (30) that links the second swinging arm (28) and the feedback arm (19), and a push-pull rond that operatively connects the first swinging arm (27) and the arm portion (8a). It consists of (31).

During automatic plowing depth control, by setting the position lever (7) to the (downward) position shown in Fig. 1 and setting the plowing depth setting lever (8) arbitrarily, the rear cover (4a)
and the feedback operation force from the helical spring (2
Automatic plowing depth control is performed by the action of the return operation force from 4), and during position control, the swinging member (23) is brought into contact with the member (20) by operating the position lever (7), and the vehicle body Even if the position lever (7) is operated to the (raised) position shown in Fig. 1, the swinging member (23) and the member (20) are in contact with each other, so the helical spring The structure is such that the urging force from (24) does not act on the position lever (7).

[Another example]

In addition to the embodiments described above, the present invention may use a coil spring, for example, as a spring for operating a hydraulic valve.

Incidentally, although reference numerals are written in the claims section for convenient comparison with the drawings, the present invention is not limited to the structure shown in the accompanying drawings.

[Brief explanation of the drawing]

The drawings show an embodiment of the lifting control mechanism for an agricultural tractor according to the present invention, FIG. 1 is a side view showing the feed pack operating system of the lifting control mechanism, and FIG. 2 is a longitudinal cross-section showing the hydraulic valve operating system. 3 is a perspective view showing a feedback system between a hydraulic valve and a lift arm, and FIG. 4 is a side view of the rear part of the agricultural tractor. (4)...Ground work equipment, (7)...
Operation lever, (9)...Hydraulic valve, (20)
... member, (23) ... rocking member, (
24)... Spring.

Claims (1)

[Claims] A member (20) that is linked to a hydraulic valve (9) that controls the elevation of the ground work device (4) and is oscillated by a feedback operation force generated in response to changes in the ground level of the ground work device (4). , is linked to the operating lever (7) for setting the level relative to the vehicle body of the ground work device (4), and is connected to the member (20).
) and a swinging member (23) that swings and deviates substantially coaxially with a spring (24) for operating a hydraulic valve.