JPH064657Y2 - Release structure of lift arm lowering rotation speed control mechanism in tractor - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION (a) Field of Industrial Application The present invention relates to a release structure capable of freely stopping the function of a damper device provided in a descending rotation speed control mechanism of a lift arm in a tractor.

(B) Conventional Technology Conventionally, a lift arm is provided on the hydraulic case at the rear of the tractor so as to be vertically rotatable so that the rotary device connected to the rear of the tractor can be vertically moved up and down by the lift arm. .

The lift arm is operated by raising and rotating the lift lever disposed on the side of the seat of the tractor to extend and lift the lift cylinder via the hydraulic valve. In addition, when the lift lever is rotated downward, the hydraulic oil in the lift cylinder can be returned to the state through the hydraulic valve, and the rotary device itself is configured to descend.

However, in the case of such a structure, since the lowering of the rotary device is performed by the weight of the device itself, when the device lands on the cultivated surface, the descending speed increases at an accelerating rate and it collides with the cultivated surface. However, depending on soil conditions, there was a problem that the rear part of the tractor was pushed up by the reaction and the tractor engine stopped.

Further, if the descending speed of the rotary device is slowed to prevent such a problem, it takes too much time to cope with the plowing work, and there is a problem that the work efficiency is affected.

Therefore, the following lift arm descending rotation speed control mechanism has been devised.

That is, a lift interlocking mechanism is provided between a lift arm protruding from the hydraulic case at the rear of the tractor so as to be rotatable up and down, and an arm lifting operation lever for operating the lift arm.
The lift interlocking mechanism is configured to vertically rotate the lift arm in conjunction with the operation of the arm raising / lowering operation lever, and a damper device is provided in the elevator interlocking mechanism so that the damper device rotates downward. This is a descending rotation speed control mechanism for the lift arm, which has a cushioning function for the lifting interlocking mechanism only from a predetermined descending position of the lift arm to suppress the descending rotation speed of the lift arm.

(C) Problems to be solved by the invention However, connecting to the rear of the tractor is not limited to the rotary device. For example, a plow-shaped excavator that requires a desired bite is also connected to the tip of the lift arm. Therefore, in some cases, it is preferable that the downward rotation speed control of the lift arm is not performed, and it is necessary to remove the damper device one by one.

Therefore, it takes time to remove the damper device,
In addition, there is a problem that the work efficiency becomes very poor because the positioning and the like when equipping the damper device again is troublesome.

(D) Means for Solving the Problems In the present invention, therefore, a lift arm that is vertically rotatable from the hydraulic case at the rear of the tractor is provided, and a hydraulic lever for lifting and lowering the lift arm and a lift lever are provided. It is configured to be linked via a lift interlocking mechanism, and the lift arm is vertically rotated in conjunction with the operation of the lift lever, and during the lift interlocking mechanism, within the operating range of the hydraulic lever,
A damper device that operates from a predetermined lowered position of the lift arm is provided, and the damper device is configured to have a piston rod slidably provided in the storage case as a buffer function by fluid resistance, and the piston rod is provided in the storage case. Is provided with a rod storage lid body for preventing the protrusion of the lift rod lowering rotation speed control mechanism in the tractor capable of storing the piston rod in the storage case.

(E) Action For example, when performing cultivating work, if the rotary device is connected to the rear of the tractor and the rotary device is connected to the tip of the lift arm, the lift arm is raised and lowered by operating the lever. The vertical movement of the rotary device can be easily performed through the arm as appropriate. At this time, when the lift arm is rotated downward, a damper device provided in the vertical movement interlocking mechanism is connected to the lift arm. If the cushioning function of the lift arm is controlled only from the position near the cultivated surface, the rotary speed of the lift arm is suppressed by the cushion device, so that the rotary device is gently grounded on the cultivated surface. It is a thing.

Then, when it is desired to stop the function of the damper device, that is, in order to cancel the downward rotation speed control of the lift arm, the rod storage lid provided in the storage case of the device is positioned on the closing side, and the rod is closed. When the rod is stored in the storage case, the lift arm does not function as a buffer for the ascending / descending interlocking mechanism, and therefore the lift arm descends due to the weight of the connected working machine.

(F) Effect According to the present invention, the descending rotation speed of the lift arm can be moderated only from the predetermined descending position, and the lift arm can be changed according to the type of each working machine connected to the lift arm. Since the descending rotation speed control can be released quickly and reliably without tools, there is an effect that the work efficiency is improved.

Moreover, since it is not necessary to remove the damper device itself,
There is no need to bother with the storage location and management of the device after it is removed, and further there is an effect that the labor such as positioning when installing the device again can be saved.

Also, as a means for stopping the function of the damper device,
Since the housing for the damper device is provided with the rod housing lid that prevents the piston rod from projecting, the structure is simple.

(G) Embodiments An embodiment of the present invention will be described in detail with reference to the drawings. (A) shown in FIG. 1 is a tractor, and the tractor (A) is located at the front of the machine frame (1) and has a prime mover part ( 2), mission case on the rear
(3) is provided, an operating section (4) is provided between them, and front and rear wheels (5) and (6) are continuously provided below the aircraft body frame (1).

The hydraulic case (7) is mounted on the upper side of the mission case (3), and the left and right lift arms (8) are installed from the rear left and right sides of the case (7).
The arm (8) (8) is provided so that it can be rotated up and down.
Is configured to rotate up and down by the expansion and contraction operation of the lift cylinder provided in the hydraulic case (7), and various working machines such as a rotary device connected to the rear of the tractor (A) are connected to the lift arm (8) ( It is possible to move up and down by 8).

The lift cylinder is a single-acting cylinder.When the hydraulic oil is supplied, the cylinder rod expands to rotate the lift arms (8) and (8) upward, and when the hydraulic oil is returned, the cylinder rod contracts. Lift arm (8)
The descending of (8) is free. (9) is the PTO axis.

The driver's unit (4) has a handle (10) at the front, a seat (11) is arranged behind the handle (10) above the hydraulic case (7), and left and right rear wheel fenders are located on the left and right sides of the seat (11). (12) (12 ') is provided, and the gear shift lever (13) is installed from the left rear wheel fender (12).
And the lift lever (14), hydraulic lever (15), and automatic plowing positioning lever (16) from the right rear wheel fender (12 ') so that various levers can be operated while seated. I am able to do it.

The lift lever (14) is the left and right lift arms (8) (8) described above.
It is an arm raising / lowering operation lever for rotating up and down. As shown in FIG. 2, the base end of the lever (14) is pivotally supported (14a) on the upper front side of the mission case (3). A lift interlocking mechanism (19) between the base end of the lever (14) and the valve opening / closing operation shaft (18) protruding from the right side wall of the hydraulic case (7) to open / close the hydraulic valve of the lift cylinder. It is arranged so that the left and right lift arms (8, 8) are interlocked with the lift lever (14) by the lifting and lowering interlocking mechanism (19).

Also, the transmission shaft (20) is laterally supported by the transmission case (3) near the lower end of the lift lever (14) base end, and the right end is extended (20a) to the right side so as to project outward. The extension portion (20a) is loosely fitted with a base end of an operating arm (21), which partially constitutes the ascending / descending interlocking mechanism (19), via a boss.
2) project, and the tip of the projecting piece (22) is interlockingly fitted to the interlocking cylinder (23) that is connected to the base end of the lift lever (14).
The operating arm (21) is configured to rotate in conjunction with 4).

Here, the structure of the lifting interlocking mechanism (19) will be described in detail below.

That is, the ascending / descending interlocking mechanism (19) has the above-mentioned operating arm (2
1) and the passive arm (2
By interposing an interlocking rod (25) with (4), the operating shaft (18) is rotated by the operation of the lift lever (14), opening and closing the hydraulic valve, and further lifting the left and right lift arms ( 8) It is configured such that the vertical rotation operation of (8) can be performed.

Moreover, the interlocking rod (25) is configured such that the main body (25a) can be extended and retracted by a turnbuckle system, and the base end (25b) is an operating arm.
(21) Linked to the tip, a long hole (25d) is formed in the tip (25c) in the longitudinal direction, and the tip (25c) is projected from the passive arm (24). Same long hole (25d) in mating sliding pin (26)
Is loosely fitted through.

The tip of the tension spring (27) whose base end is fixed at a predetermined position is connected to the tip of the engaging slide pin (26), and the passive arm (24) is driven by the tension urging force of the spring (27). ), The valve opening / closing operation shaft (18) is rotated to operate the hydraulic valve on the hydraulic oil return side.

Therefore, with the lift lever (14), the left and right lift arms
(8) When raising (8), the operating arm (21) moves the interlocking rod.
(25) pushes and rotates the passive arm (24) through the engagement slide pin (26), and the hydraulic valve is operated to the hydraulic oil supply side in accordance with the rotation of the pulsating operation shaft (18). The left and right lift arms (8) (8) rotate upward as the lift cylinder extends.

At this time, the passive arm (24) is rotated by the tension spring (27).
This is done against the pulling force of.

In addition, the left and right lift arms (8) (8) by the lift lever (14).
When the lower arm is operated, the actuating arm (21) pulls the interlocking rod (25), but the passive arm (24) engages the sliding pin.
Since (26) slides in the long hole (25d), it does not rotate integrally with the interlocking rod (25), but after a while, it is rotated by the tension urging force of the tension spring (27), The hydraulic valve is actuated to the hydraulic oil return side so that the left and right lift arms (8) (8) can be freely rotated downward.

At this time, if a working machine such as a rotary device is connected to the ends of the left and right lift arms (8) and (8), the work machine is lowered by its own weight.

In addition, the lifting interlocking mechanism (19) has a damper device (28).
Is configured to function as a buffer function to control the downward rotation speed of the lift arm, which will be described in detail below.

That is, as shown in FIGS. 2 and 3, the damper device (28) includes a storage case (28a), a piston (28c) slidably provided in the storage case (28a), and the piston. (28c) and a piston rod (28d) that is integrally formed with the storage case (28a) and projects from the storage case (28a) so as to slide back and forth.
When d) slides backward into the storage case (28a), it is configured to be buffered by the fluid in the storage case (28a).

The damper device (28) is housed in the storage case (28a), and the rod sliding hole (28b) provided in the front side wall (28'a) of the case (28a) is used to store the damper device (28). The piston rod (28d) can be freely projected to the outside of the case.
8'a) and the front of the storage case (28a) have a spring between them.
(28e) is interposed, and a damper device advancing / retreating adjustment bolt (28f) is attached to the rear side wall of the storage case (28a).

Reference numeral (29) is a support bracket that supports the damper device (28).

Therefore, since the advance / retreat position of the damper device (28) can be easily adjusted by the adjustment bolt (28f), the shock absorbing condition of the damper device (28) can be easily adjusted.

Therefore, for example, when the rotary device is connected to the ends of the left and right lift arms (8) (8) and the lift arms (8) and (8) are lowered by the lift lever (14), as described above, the tension spring The same lift arm quickly due to the urging force
(8) The rotary device is descended through (8), but the contact piece (30) contacts the piston rod (28d) of the damper device (28) and pushes the rod (28d). When pushed and retracted, at the same time, the contact piece (30) begins to receive the fluid buffering effect in the storage case (28a), and the rotary device descends slowly.

At this time, if the timing at which the damper device (28) starts the buffer function is set to a position near the cultivated surface of the rotary device, the rotary device will collide with the cultivated surface and the machine will stall. Is solved and the work efficiency can be secured.

In the present invention, the damper device (28) may be any device as long as it provides a cushioning function by advancing and retracting the piston rod.

In such a configuration, the gist of the present invention resides in the lift arm lowering rotation speed control release structure, which will be described in detail below with reference to FIGS. 3 to 6.

That is, the upper portion of the rod storage lid (31) is pivotally supported (32) on the front side wall (28'a) of the storage case (28a) along the front side wall (28'a) surface. The lid body (31) is configured to open and close the rod sliding hole (28b).

Then, the rod storage lid facing the rod sliding hole (28b)
In the center of the back surface of (31), a curved curved concave portion (31a) is formed and a guide groove (31b) is formed from the concave portion (31a) to the outer end of the lid body (31) on one side of the back surface. ) Form a communication,
On the opening end side of the guide groove (31b) of the lid body (31), there is provided a sled portion (33).

Therefore, when releasing the lift arm lowering rotation speed control, the piston rod (28d) of the damper device (28) is contacted by the contact piece.
Storage case for the same rod (28d) so as not to buffer with (30)
The piston rod (28d) must first be housed inside the (28a).
By pressing the button, it is retracted into the storage case (28a), and in the same state, the guide groove (31b) on the back surface of the rod storage lid (31).
While sliding the piston rod (28d) to the tip of the curved curved concave part (31a) to the tip of the rod (28d), the piston rod (28d) is stored in the storage case (28a). It is held and does not interfere with the contact piece (30).

When releasing the rod storage state, reverse the above procedure and rotate the rod storage lid (31) upward to open the rod sliding hole (28b). The rod (28d) protrudes forward in the sliding hole (28b) to fulfill the function of controlling the lift arm descending speed.

In addition, the hydraulic lever (15) has a basal opening / closing operation shaft (18) at the base end.
It is loosely fitted to the passive arm (24) and is arranged adjacent to the passive arm (24) .A locking piece (15a) is provided on the front side of the base end of the lever (15) so as to project toward the front side surface of the passive arm (24). Only when the left and right lift arms (8) and (8) are raised by the hydraulic lever (15), the locking piece (15a) engages with the passive arm (24), and the same arm (24) is moved to the hydraulic lever (15). It is configured to operate in conjunction with (15). (1
7) is a stopper body.

Therefore, when the hydraulic lever (15) is operated to the required rotation position, the passive arm (24) is locked by the locking piece (15a) of the lever (15), that is, the left and right lift arms. (8) It is possible to change the lower limit position of (8) appropriately, and to operate the lever (15) to move the left and right lift arms (8) (8) up and down. Is also possible.

That is, the hydraulic lever (15) also functions as an arm raising / lowering operation lever.

Further, the automatic plowing depth positioning lever (16) is a lever for controlling the descending position of the left and right lift arms (8), (8), and if the plowing depth is initially set by the lever (16), The descent position of the lift arms (8) (8) is automatically controlled, and the lowest descent position of the rotary device connected to the lift arms (8) (8), in other words, the plowing depth is always kept constant. It is what is done.

[Brief description of drawings]

FIG. 1 is a side view of a tractor having a release mechanism of a lowering rotation speed control mechanism of a lift arm according to the present invention. FIG. 2 is an enlarged sectional view of the main part. FIG. 3 is a side sectional view of the damper device. FIG. 4 is a front view of the damper device. FIG. 5 is a rear view of the rod storage lid. FIG. 6 is a side view of the storage lid. (A): Tractor (7): Hydraulic case (8): Lift arm (14): Lift lever (19): Lifting interlocking mechanism (28): Damper device (28a): Storage case (28d): Piston rod

Claims (1)

[Scope of utility model registration request] 1. A lift arm (8) projecting vertically from a hydraulic case (7) at the rear of the tractor (A) is provided,
Hydraulic lever (15) for lifting and lowering the lift arm (8)
And the lift lever (14) are connected via a lifting interlocking mechanism (19), and in conjunction with the operation of the lift lever (14),
The lift arm (8) is configured to be vertically rotated, and the hydraulic lever (1
Within the working range of 5), a damper device (28) that operates from a predetermined lowered position of the lift arm (8) is provided, and
The damper device is configured such that a piston rod (28d) slidably provided in the storage case (28a) serves as a buffer function by fluid resistance, and the projection of the piston rod (28d) is provided in the storage case (28a). A structure for releasing a lift arm lowering rotation speed control mechanism in a tractor, which is provided with a rod storage lid (31) for preventing the piston rod (28d) from being stored in a storage case (28a).