JPH01179601A - Driving mechanism for lifting or lowering working device of agricultural tractor - Google Patents

Abstract

PURPOSE:To enable driving, lifting and lowering of lift arms with excellent operating efficiency according to soil quality and working condition, by enabling release of linking of lowering the lift arms to decelerating thereof. CONSTITUTION:An oil quantity regulating member 17 for regulating lifting speed of lift arms 3 is linked through a linking member 20 to one of the lift arms 3. The oil quantity regulating member 17 is pushed from a state moved to the outside by a recessed part 28 to contact a linking member 22 into a weight reduction regulating position based on downward rocking displacement from the set positions of the lift arms 3. Thereby, the lift arms 3 are lowered at a low speed. When an operating lever 24 is operated to rotate an operating member 25, the linking member 22 can be changed over to a position for contacting the oil quantity regulating member 17 and position for releasing the linking by a bent part (25a). As a result, decelerating state of the lift arms can be changed over.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a working device lifting/lowering drive mechanism for an agricultural tractor.

[Conventional technology]

As the conventional drive mechanism, for example, the Japanese Patent Publication No. 61
As disclosed in Publication No. 25323, when the lift arm is raised, it is configured so that it always rises at high speed, and when the lift arm is lowered, it reaches a predetermined plowing depth from just before the ground work equipment touches the ground. There is one that is configured so that the return oil from the lift cylinder is squeezed within a predetermined height range until the lift arm is lowered at a low speed.

[Problem to be solved by the invention]

The structure of the above-mentioned example is intended to prevent the occurrence of engine stop or dancing phenomenon caused by rapid grounding of the ground working machine during plowing work in heavy clay fields, for example. However, when the lift arm is lowered, it always descends at a low speed within the predetermined height range, so that the predetermined plowing depth can be reached even when plowing in fields with light soil where there is no risk of engine stoppage or dancing phenomenon. There was an issue that needed to be improved in that the work efficiency was reduced because the machine descended at low speed.

The present invention has been made with this point in mind, and an object of the present invention is to enable lift arm lifting and lowering drives with good work efficiency in accordance with the soil quality and working conditions through a simple switching operation.

[Means to solve the problem]

A feature of the present invention is that the amount of oil adjustment member for adjusting the amount of oil discharged from the hydraulic cylinder for driving the lift arm is reduced based on the swinging displacement downward from the set position of the lift arm that drives the work equipment up and down. A linking member is provided that is mechanically linked to the side to reduce the descending speed of the lift arm, and this linking member is switched between a lift arm reduction action state and a lift arm deceleration disabled state in which the linkage is released. The device is equipped with an operating member to be operated, and its functions and effects are as follows.

[For production]

When the operating member is set to the lift arm reduction action state, the lift arm swings downward from the set position, that is, the position immediately before the work equipment touches the ground, and operates the oil amount adjustment member toward the reduction side. As a result, the lowering speed of the lift arm is reduced, and the work equipment touches the ground at a low speed. and,
When the operating member is set to a state in which the lift arm cannot be decelerated, the link between the lift arm and the oil amount adjusting member is released.
The lift arm can be driven at high speed both when ascending and descending.

〔Effect of the invention〕

Therefore, according to the present invention, in heavy clay fields where there is a risk of engine stoppage or dashing phenomenon when the work equipment is grounded, the lift arm can be set to the non-coupling state and the work equipment can be grounded at a low speed. In fields with light soil where there is no risk of the above problems occurring, the lift arm can be set to a state where deceleration is not possible and the lift arm can be driven at high speed throughout the entire ascending and descending stroke, eliminating unnecessary waiting time and improving work efficiency. has improved.

Additionally, it is conceivable to use an electrical control mechanism to achieve the above-mentioned functions and effects, but agricultural tractors are generally used in harsh environments, and such electrical control may have poor durability and reliability. However, since the present invention is constructed with a simple mechanical mechanism, it can be constructed at low cost without deteriorating durability or reliability.

〔Example〕

As shown in FIG. 5, a pair of left and right lift arms (3) are provided at the rear of the body (1) of the agricultural tractor and are operated to swing vertically by a single-acting hydraulic cylinder (2).

(3), and a three-point link mechanism (4) that is driven and moved in conjunction with these lift arms (3), (3), and the three-point link mechanism (4) is an example of a working device. A rotary tiller (5) is detachably connected thereto.

The three-point link mechanism (4) includes a pair of left and right lower links (6) that connect the machine body (1) and the rotary tiller (5).
, (6), the top link support (7) attached to the rear upper side of the fuselage (1), and the rotary tilling device (5).
) and a top link (9) that connects the attached top mast (8).

Then, the lift arms (3), (3) and the lower links (6), (6) are connected to the lift arms (10).
), (10), and the hydraulic cylinder (2
) The three-point linkage mechanism (4) can be driven and swung by the telescopic operation. And a rotary tiller (
The input shaft (11) of 5) and the power take-off shaft (12) protruding from the rear of the machine are interlocked and connected via a bendable transmission shaft (13) which is detachably connected to these to form a rotary tiller. (5).

As shown in FIGS. 1 to 4, the hydraulic cylinder (2
) is connected to the transmission case (16) from the oil chamber (15) of the hydraulic cylinder (2) when lowering the rotary tiller (5) from the raised position.
Oil amount adjustment member (17) that adjusts the amount of drained oil returned inside
This is provided. That is, an oil amount adjusting member (17) that functions as a slidable throttle valve is provided in the oil supply and drainage path for hydraulic oil to the hydraulic cylinder (2), and as shown in FIG. When the member (17) moves outward, the member (17)
Drained oil flows out from the gap (S) between the inner end surface of the support member (19) and the contact member (18), and the cylindrical portion (19a) of the support member (19) slidably supports the oil amount adjustment member (17). A large amount of oil passes through the large-diameter passage hole (20) formed in and flows out into the transmission case (16) via a control valve (not shown), causing the lift arms (3) and (3) to descend at high speed. That's what I do. Furthermore, when the oil amount adjusting member (11) is inserted into the head portion (14), the end surface of the member (17) corresponds to the abutting member (18), as shown in FIG. In this state, the oil flows out through the small diameter orifice (21) formed in the cylindrical portion (17a) of the oil amount adjusting member (17), and the flow rate is adjusted to decrease. ) and (3) descend at low speed.

Moreover, the oil amount adjusting member (17) and one lift arm (
3) is mechanically linked via a linking member (20), and this linking member (2) adjusts the amount of oil based on the swinging displacement of the lift arm (3) downward from the set position. The adjustment member (17) is linked to be pushed into the weight loss adjustment position. In other words, the connecting member (22) is connected from the vicinity of the swinging end of the lift arm (3) to the cylinder head (1).
4), and its rear end is fitted into a support bracket (23) that is rotatably supported on the lift arm (3) around the horizontal axis (P), and the rear end of the lift arm The structure is such that the front and back displacements are interlocked with the rocking displacement (3). On the other hand, the front end of the connecting member (22) is externally supported by the supporting member (19) so as to be freely rotatable, and an operating member (25) that can be rotated by an extended operating lever (24). It is loosely inserted and supported by the bent portion (25a) of the. As shown in FIG. 3, this operating member (25) is configured so that it can be oscillated within a predetermined range and held in position at the oscillating end by means of a pole detent mechanism (26) and a stopper pin (27). When the member (25) is set to swing downward, the connecting member (22) moves to the oil amount adjusting member (17).
(hereinafter referred to as the set state), and when switched upward, the contact between the connecting member (22) and the oil amount adjustment member (17) is released (hereinafter referred to as the released state). It is structured like this.

And, in the middle part on the rear side of the linking member (22),
In the cent state, a recess (28) is formed that allows the oil amount adjusting member (17) to move outward, and as shown in FIG.
) to the tilling device (5) from the setting position (S) slightly before landing on the ground.
Until the oil amount adjustment member (ET) is lowered to
7) is located at a position corresponding to the recess (28), and the lift arm (3) descends at high speed. And lift arm (
3) is lowered below the set position, the oil amount adjusting member (
17) is brought into contact with and regulated by the linking member (22), and the lift arm (3) descends at a low speed.

Further, when the operating member (25) is set to the released state, the oil amount adjusting member (17) can always move outward, and the lift arm (3) is always in a high-speed descending state over the entire stroke. be.

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 and lowering drive mechanism for the working device of an agricultural tractor according to the present invention, in which FIG. 1 is a cutaway plan view, FIG. 2 is a side view, and FIG. 3 is a cross-sectional view taken along line II [-■ in FIG. , FIG. 4 is a cross-sectional plan view of the main part, and FIG. 5 is a side view of the rear part of the agricultural tractor. (2)...Hydraulic cylinder, (3)...
Lift arm, (17)... Oil amount adjustment member, (
22)... Oil amount adjustment member, (25)...
・Operation parts.

Claims (1)

[Claims] A system for adjusting the amount of oil discharged from the hydraulic cylinder (2) for driving the lift arm (3) based on the swinging displacement downward from the set position of the lift arm (3) that drives the work device (5) up and down. A linking member (22) is provided that mechanically links the oil amount adjusting member (17) toward the reduction side to reduce the descending speed of the lift arm (3). (3) A working device lifting/lowering drive mechanism for an agricultural tractor, which is provided with an operating member (25) for switching between a decelerating state and a lift arm non-decelerating state in which the link is released.