JPS60262501A - Working machine up-and-down movement operation apparatus in tractor - Google Patents

Abstract

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

Description

DETAILED DESCRIPTION OF THE INVENTION Field of Industrial Application This invention relates to a VC for raising and lowering a working machine connected to a towing vehicle such as a tractor, and in which the working machine raising and lowering mechanism is at a high position on 11A. This is intended to reduce the large stopping impact when reaching 1-.

Conventional technology When the work equipment lifting mechanism reaches the position instructed by the lifting instruction member, the spool of the control valve is configured to return to the middle position by feedback of this reaching movement θ). However, in the vicinity before the indicated position, the feedback operation gradually becomes smaller, so that the return movement of the spool to the neutral position becomes extremely slow, and it is difficult to return the spool to the neutral position.

Problems to be Solved by the Invention Particularly when the work equipment lifting mechanism is operated to the highest position, the amount of pressure oil supplied to the lift cylinder is at its maximum, but the return movement to the q position in the spool is slow. As a result, high pressure acts on the hydraulic circuit for a long period of time, and as a result, a large force acts on the hydraulic circuit and the working machine lifting mechanism, resulting in a large impact force.

Means for Solving the Interval Vertex Accordingly, the present invention has taken the following measures to ensure that the control valve can quickly return to the neutral position when operating near the highest position on ljj.

That is, the control valve (4) that controls the supply and discharge of pressure oil to the lift cylinder (8) of the work equipment lifting mechanism (3) is operated by the position mechanism (6) linked to the lifting instruction member (5). In the work equipment lifting operation device configured to return the control valve (4) to the middle Q state when the work equipment lifting mechanism (3) reaches the position indicated by the lifting instruction member (5), the work equipment lifting mechanism Based on (3), the position mechanism (6
Upper limit feedback mechanism C40 that feeds back to j
), and this upper limit feedback mechanism (:(0) is
The position mechanism (6) is configured to slightly return the control valve (4) toward the lowered position in the above-mentioned immediately preceding raised state.

EMBODIMENT AND OPERATION Next, an embodiment of the present invention will be described with reference to FIG. 1 showing a side view of the main part and FIG. 2 showing a partially expanded view or rear view.

The control valve (4) of the work equipment elevating mechanism (3), in which the work equipment (1) is suspended by lift arms f2) + 2), is activated by the position mechanism (4) as the elevating instruction member (5) rotates. The spool (6) moves the pressure oil of the pump to the lift cylinder (8) and discharges it from the lift cylinder (8). When the arm f21 (2) reaches, the feedback mechanism (9) returns the spool (force) to the neutral position. In other words, the position mechanism (6) in the illustrated example Armi! Hot water is fixed on the operating shaft (lυ), and the spool (7
), the upper part of the position link (+4) is connected to the upper part of the arm 021 by the pin 09, and the upper part of the position link (+4) is connected to the upper part of the arm 021 by the pin 09.
5) is connected to the upper part of the lever 1171 which is rotatably fitted to the operating shaft 1171 with the link 0 mark, and the arm 1171 is fixed to the operating shaft 1171 and the spring (not shown) The feedback mechanism (9) in the illustrated example has the bin 1 attached to the pivoting base of the lift arm (2).
? The l-dar link (2+1) connected at α and the vertically intermediate portion of position link A are interlocked by feedback link (2 sides and its bin fs!3), 124, and the elevation instruction member (5 ) in the upward direction shown by arrow A in Figure 1, lever 07) and link f+91 rotate clockwise, and the operating shaft (lυ and arm f121 also rotate clockwise, so position link (1) Desk bottle (24
) rotates clockwise around the spool (the force moves in the direction of arrow B from the neutral position in Figure 1, and the control valve (4)
Pressure oil is supplied to the lift cylinder (8) through the
will have a rising motion, and the link! 211 rises and the feedback link (221 moves to the right in FIG. 1, which causes the position link (I
4) in the counter-arrow B direction, the spring (2gl
, the spool (7) begins to return towards the neutral position,
When the lift arm (2) + 2) reaches the height instructed by the lift instruction member (5), the spool (7) returns to the neutral position and the supply of pressure oil to the lift cylinder (8) is stopped. Moreover, when the elevation instruction member (5) is operated in the downward direction opposite to the arrow A direction, each member operates in the opposite direction to that described above.

Then, the upper part of the cam arm (A) pivoted at the cylinder case pin (2) and the upper part of the lever (171)
b) are connected with a rod ((5) whose length is adjustable, and a cam (4) is fixed to the rotating base (2a) of the lift arm (2). The cam (2 hammers are the cam arm @
Make sure not to touch the lift arms (2) (2).
When 1 moves upward and reaches just before the highest position on i3, the cam 1281 contacts the cam arm (20), and as shown in Fig. 1, the cam (2) pushes the cam arm in the direction of arrow C. As the rod (271) moves in the same direction, the lever (lη
rotates a little counterclockwise and arm 01! i Return a little in the counter-arrow B direction, thereby moving the spool (7) a little in the downward direction in the counter-arrow B direction.
East Cam arm (4), the upper limit feedback mechanism (7) consisting of a rod (oil) that transmits the movement of the cam arm (A) to the lever 0η.
) to the high lifting amount position, the control valve (4) is slightly operated to the lower position (a) just before the lift arm f2) T2+ reaches the highest position. Therefore, the lift cylinder (
8) The pressure oil supply operation to 1. ,spool(
The force quickly assumes a neutral position.

The upper limit feedback mechanism r30) may be formed by mechanical means other than those shown in the drawings, or may be formed by electrical means. Further, the position mechanism (6) and the feedback mechanism (9) may also have structures other than those shown.

Effects of the Invention As described above, the present invention has an upper limit feedback mechanism f: (0) that feeds back to the position mechanism (6) the state in which the work equipment lifting mechanism (3) has reached the height just before the highest lifting height. This upper limit feedback mechanism 13 is provided.
0) is configured so that the position mechanism (6) moves the control valve (4) slightly back toward the lowering position when the position mechanism (6) has reached the above-mentioned immediately above-mentioned state, so that the work equipment lifting mechanism (3) When 113H rises to the highest position, just before reaching the turning height, the control valve (4) is slightly returned to the lowered position by the action of the upper limit feedback mechanism S (υ). In order to
The control valve r4) will quickly return to the middle ((, position), and the time for the upward movement of the control valve (4) at the highest position, where high pressure will act on the hydraulic circuit, can be shortened. As a result, it was possible to reduce the impact force acting on the hydraulic circuit and the working machine lifting mechanism (3) at the time of stopping.

[Brief explanation of drawings]

The drawings show an embodiment of the present invention, in which Fig. 1 is a side view of the main part of the device, Fig. 2 is a view 1 m after partially expanded from Fig. 1, and Fig. 3 is an overall side view of the towing vehicle. Description of symbols (3)...Work equipment lifting mechanism (4)...Control valve (5)...Lifting/lowering instruction member (6)...Position mechanism (8)...Lift cylinder ('tn)・−
Upper limit feedback mechanism agent Patent attorney Takayoshi Hayashi

Claims (1)

[Claims] Work equipment lifting mechanism α) The control valve for supplying and discharging power oil to the lift cylinder is operated by a positioning mechanism that is linked to the lifting instruction unit (a), and the work equipment lifting mechanism is moved to the position indicated by the lifting instruction member. In the work equipment lifting/lowering operating device, the control valve is centered in the middle position when reaching the highest position.In the work equipment lifting/lowering operating device, the state of reaching the lift just before the highest position is fed back to the position mechanism by the work equipment lifting/lowering mechanism. The upper limit feedback mechanism is characterized in that the upper limit feedback mechanism is configured to slightly return the control valve toward the lowering device when the position mechanism reaches the above-mentioned TM (before) upward movement state. Work equipment lifting/lowering control device for towing vehicles.