JPS6125323B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a lifting device for a ground-based work machine such as a rotary, and when lowering the ground-based work machine to a target working depth before starting work, it is necessary to By slowing the descent speed from the predetermined position in This paper proposes a lifting device for ground-based work equipment that is devised to allow rapid lifting without limiting the function of the lift mechanism during lifting operations that do not require speed control. Japanese Utility Model Application No. 52-95813 discloses a device configured to throttle oil returned from a hydraulic cylinder so that the speed of elevation and descent of a ground-based work machine is slow within a predetermined height range. However, this device is inefficient because a throttling action also occurs during the upward movement.

In addition, a control device is disclosed in which the lowering operation of a lift arm and the throttle operation of a throttle valve are linked by electric means such as a limit switch so as to slowly control the lowering operation of a ground work machine before and after touching the ground. It is known as No. 101683 (Sho 51-101683), but,
In this known device, the throttling action is performed even when the ground work machine is descending below the point where it touches the ground, so the descending motion during plowing is slow and the control response is poor. The device requires electrical means and is disadvantageous in terms of cost.

Therefore, the present invention is configured by mechanical means so that in the ascending operation, it is possible to ascend rapidly without any throttling action, and in the descending action, the slow descending due to the throttling action occurs only within a predetermined height range. This is what I did.

That is, the ground work machine 3 connected to the tractor
In the lifting device for ground work equipment, which can be raised and lowered by a lift mechanism 4 having a lift cylinder 8 operated by a hydraulic device 7, a throttle mechanism 14 that squeezes return oil from the lift cylinder 8, and a lift arm 5.
The lift mechanism 4 is configured to operate the throttle mechanism 14 within a predetermined height range of the ground work equipment 3 when the lift arm 5 is lowered, and to keep the throttle mechanism 14 inactive when the lift arm 5 is moving upward. and a mechanical interlocking mechanism 27 that interlocks the throttle mechanism 14.

Next, the specific structure will be explained based on the illustrated embodiment. As shown in FIG. 1, the ground work machine 3 can be raised and lowered by a coupling device 2, such as a three-point linkage device, at the rear of the tractor 1. The lower link forming the coupling device 2 is connected to the lift mechanism 4.
is suspended from lift arms 5, 5 via lift arms 6, 6, and pressurized oil from a hydraulic device 7 provided on the tractor 1 is supplied to or discharged from a lift cylinder 8, and the lift arm 5 is moved in and out by the movement of a hydraulic piston 9. ，
5 can be moved up and down.

Therefore, in this invention, as shown in FIG. A cam portion 11a with a circular cross section provided at one end of the cam 11 is always elastically attached in the direction of the arrow A in FIG. The contact portion 11 of the cam 11
The actuating body is provided so that b comes into contact with the rotating base of the lift arm 5. On the other hand, as shown in FIG.
When the lift arm 5 is raised by operating the hydraulic device 7, the pressure oil passes from the hydraulic device 7 through the oil passage 15, through the gap between the check valve 16 of the throttling mechanism 14 and the check valve seat 16a, and into the hollow cylinder. The throttle valve 17 is pushed back against the valve spring 18 to flow into the lift cylinder 8 through the through hole 19 and push the hydraulic piston 9, and the lift arm 5 in the raised position is lowered. Hydraulic system 7
When the valve spring 18 is operated as shown in FIG.
The throttle valve, which has been pushed back by Valve seat 16
It returns to the hydraulic system 7 from the oil passage 15 through the gap between the oil passage a and the oil passage 15, and is discharged into a tank (not shown).

Then, the push rod 21, which has a seat 21b communicating with the relief hole 17a passing through the hollow part of the throttle valve 17, is loosely fitted through the lid 22 of the throttle mechanism 14, and the push rod 21 projects out of the lid 22. It is set up like this. Further, the straight rod portion 23a of the L-shaped lever 23 is rotatably supported by brackets 24, 24 attached to the case of the lift cylinder 8, and the arm portion 23b of the lever 23 is rotatably supported. The fitted roller 25 is made to come into contact with the cam part 11a of the cam 11, and the push plate 26 fitted with a spline at the end of the straight rod part 23a is always brought into contact with the push rod 21 of the aperture mechanism 14, as shown in FIG. When the lift arm 5 is in the raised position and the ground work equipment 3 is sufficiently lifted from the ground as shown by the solid line, the cam 11 is in the lowered position, and the arm part 23b that contacts the cam part 11a is in the lowered position. The push plate 26 is kept in a position far away from the throttle mechanism 14, but when the lift arm 5 is lowered and the ground work equipment 3 reaches a predetermined position before reaching the target working depth, it is lowered as shown by the two-dot chain line in the same figure. The cam portion 11a, which is reversely rotated upward by the rotated lift arm 5, pushes up the arm portion 23b via the roller 25, and by the rotation of the straight rod portion 23a, the push plate 26 is moved to the fourth position. As shown in the figure, the throttle valve 17 is pushed down toward the check valve 16 together with the push rod 21 against the valve spring 18. As a result, the throttle valve 17 disconnects the through hole 19 and the chamber 20, so that the lift cylinder The pressure oil in the lift cylinder 8 passes through the thin relief groove 27 and returns to the oil passage 15 from the thin relief groove 21a of the seat 21b through the relief hole 17a. Since the return oil is limited, the lowering speed of the lift arm 5 is formed to be slow, and when the lift arm 5 rotates further downward and the ground work equipment 3 reaches the target working depth, the circular cam portion 11a will come off the roller 25 and enter the gap between the roller 25 and the lift arm 5, and the pushing up of the roller 25 will be released and the push plate 2
6 no longer pushes back the throttle valve 17, and the restriction on the speed of draining oil from the lift cylinder 8 is also lifted.

If the lift arm 5 is rotated upward from the lowered position of the lift arm 5, the roller 25
The cam portion 11a inserted between the rotation base of the lift arm 5 and the rotation base of the lift arm 5 comes into contact with the right side of the arm portion 23b in FIG.
3b cannot be rotated, so the cam part 11a escapes to the clockwise and rotates due to the torque spring 13.
The throttle mechanism 14 is not activated, and the lift arm 5 is configured to move up and rotate quickly, and an interlocking mechanism 27 such as a lever 23 that interlocks and transmits the movement of the cam 11 to the throttle mechanism 14 is used. Configure.

Therefore, when the lift arm 5 is raised and the ground work equipment 3 is sufficiently lifted from the ground, when the hydraulic device 7 is applied and the lift arm 5 is rotated downward, the cam portion 11a is rotated upward. As a result, the lever 23 rotates and gradually pushes the throttle valve 17 down toward the check valve 16 via the push plate 26.

When the ground work device 3 reaches a predetermined position before reaching the target working depth, the throttle valve 17 cuts off the communication between the through hole 19 and the chamber 20, as shown in FIG. Pressure oil has a thin relief groove 2
7 and the escape groove 21a, and return to the hydraulic system 7 via the oil passage 15, the lowering speed of the lift arm 5 and the ground work equipment 3 becomes gentle.

Then, when the ground work machine 3 reaches the target working depth in this way, the cam portion 11a is removed from the roller 25, so the arm portion 23b returns to its original position and the throttle valve action by the throttle valve 17 is also canceled.

The ground work equipment lifting device according to the present invention is configured as described above, and when the lift arm 5 is lowered, it operates in conjunction with the lift mechanism 4 within a predetermined height range of the ground work equipment 3. Interlocking mechanism 2
7 causes the throttle mechanism 14 to perform a throttle operation to squeeze the return oil from the lift cylinder 8, so the ground work equipment 3 gradually descends, and after passing a predetermined height range, the throttle mechanism 14 becomes inactive and ground work is resumed. Since the descending speed of the machine 3 is normal, for example, from just before the ground work machine 3 descends and touches the ground until it touches the ground and reaches a predetermined plowing depth, it descends slowly, reducing the workload. This prevented a sudden increase in fuel consumption and prevented engine stalling and dashing.

Then, when descending from a deep position past the predetermined plowing depth, and during the entire range of the lifting movement of the lift arm 5, the throttle mechanism remains inactive, so the hydraulic system can, for example, issue instructions for raising and lowering using the raising and lowering operation lever. The ground working machine 3 operates in response to the operation quickly, and therefore, the plowing depth is controlled by rapidly moving up and down at a normal speed without any throttling action.

In other words, after touching the ground, it is possible to control the plowing depth of the ground work machine at a normal speed that is not subject to the throttling action. The sharpness of the vertical movement is not impaired, and the excellent characteristics of good responsiveness can be demonstrated.

In particular, the present invention provides an interlocking mechanism 27 that interlocks the lift mechanism 4 and the aperture mechanism 14.
Since it is mechanically constructed, there are no factors such as a power supply and electrical wiring that increase production costs, and the lifting device can be made low in cost and easy to maintain.

[Brief explanation of the drawing]

Each figure shows one embodiment of the invention.
The figure is a side view of a tractor with a ground work equipment suspended.
FIG. 2A is a side view of the operating body and the interlocking device, FIG. 2B is a plan view of FIG. Description of symbols 1...tractor, 2...coupling device, 3
... Ground work equipment, 4... Lift mechanism, 5... Lift arm, 6... Lift rod, 7... Hydraulic system, 8... Lift cylinder, 9... Hydraulic piston, 10... Bracket, 11... Cam, 11a... Cam part, 11b... Contact part, 12... Pin, 113... Torque spring, 14... Throttle mechanism, 15... Oil path, 16... Check valve, 16a
...Check valve seat, 17a...Escape hole, 18...Valve spring, 19...Through hole, 20...Chamber, 21...Push rod, 21
a, 27... Relief groove, 21b... Seat, 22... Lid, 23
...Lever, 23a... Straight rod part, 23b... Arm part, 24
...Bracket, 25...Roller, 26...Press plate, 2
7...Interlocking mechanism.

Claims (1)

[Claims] 1. In a ground work equipment lifting device that enables a ground work machine connected to a tractor to be raised and lowered by a lift mechanism having a lift cylinder operated by a hydraulic device, a throttle mechanism that squeezes return oil from the lift cylinder, and a lift When the arm descends, the throttling mechanism is operated within a predetermined height range from just before the ground work equipment touches the ground until it reaches a predetermined plowing depth, and when the lift arm is ascending, the throttling mechanism is disabled. A ground work equipment elevating device for a tractor, comprising a mechanical interlocking mechanism that interlocks a lift mechanism and a throttle mechanism so that they remain in operation.