JPH071927Y2 - Draft control device for tractor - Google Patents

Description

TECHNICAL FIELD The present invention relates to a draft control device for a tractor.

Conventional technology A top link mounting member that is rotatably supported in the machine body is linked to a hydraulic control device, and the top link mounting member senses the compressive force applied to the top link due to the increase in traction resistance of the working machine, and hydraulic control is performed. The draft control of the tractor is designed so that the tractor can be prevented from slipping by keeping the traction load constant by raising the work implement by switching the device, and the draft control of the tractor is located at the position corresponding to the position of the control lever. It is already known as one of hydraulic control mechanisms and put to practical use together with a position control for adjusting the height of the hydraulic pressure control and a mix control having both a draft control and a position control.

In such a draft control device, when the draft is not used, for example, when the position control operation or the mix control operation is performed, the top link mounting member is fixed so as not to move even if a thrust from the working machine is applied, as shown in FIG. A stopper (c) rotatably attached to the upper part of the link mounting member (a) via a support shaft (b) is fixedly secured to the hydraulic case (e) by straddling the stopper bolt (d). A structure is provided in which the bracket (f) and the top link mounting member (a) are intervened and locked, and the stopper (c) is rotated upward during the draft operation to release the lock. Kosho 61-15
No.

However, in the above-mentioned conventional device, the stopper bolt (d) is provided in the widthwise intermediate portion of the machine body near the upper end of the top link mounting member (a) that performs the sensor function as shown in the figure. Since the stopper (c) is located above it, the top link mounting member (a) is long in the vertical direction, and the sensor part (g) uses a narrow space on the rear side of the hydraulic case (e). Due to the structure of the machine, the stopper (c) may easily interfere with the seat member bracket or the tool box provided at the rear of the seat depending on the model.
Therefore, it may be difficult to secure a mounting space for the stopper (c).

Therefore, according to the present invention, the top link mounting member is supported rotatably in the front-rear direction with respect to a bracket fixed to the machine body through bracket fixing bolts. A stopper for restricting the forward rotation of the top link mounting member is hung vertically and slidably in a longitudinal direction through a stopper bolt provided outside the bracket fixing bolt and is slidable in the longitudinal direction. The stopper is held in the actuated state when the bracket fixing bolt is located on one side and is held in the non-actuated state when positioned on the other side. It is a thing.

Action When using the draft control, if the stopper is hung vertically, the stopper's rotation restricting action on the top link mounting member is released, so the top link mounting member is pushed by the top link due to the increase in the traction resistance of the work machine and moves forward. Freely rotate to switch the hydraulic control device to the raising side,
The work machine rises. When the traction resistance decreases as the working machine rises, the top link mounting member returns to its original position by the leaf spring, and the working machine descends. On the other hand, when the draft control is not in use, if the stopper is located on the opposite side with the bracket fixing bolt sandwiched, the stopper intervenes between the top link mounting member and the bracket and the forward rotation of the top link mounting member is restricted. Will not be done.

Embodiments The structure of the present invention will be described with reference to an embodiment shown in the drawings. Reference numeral 1 is a hydraulic case of a tractor, which is fixedly mounted on the upper surface of a transmission case not shown. Reference numeral 2 denotes a lift arm extending from the side of the hydraulic case 1 toward the rear of the machine body (left side in FIG. 1). The extension end side of the lift arm is not shown in the drawing, but is connected to the lower link of the working machine mounting device via the lift rod. The lift arm 2 is vertically moved by the switching operation of the hydraulic control device incorporated in the hydraulic case 1 so as to raise and lower the working machine. Reference numeral 3 denotes a bracket integrally provided with an arm 3a. The bracket 3 is fixed to the rear side of the hydraulic case 1 by bracket fixing bolts 4 and 5 screwed up and down two by two on the left and right. Reference numeral 6 denotes a top link mounting member which is rotatably supported in the arm 3a via a pivot pin 7 in the front-rear direction. A plate formed by fixing each of the receivers 6b.
6c is fixed together. The plate 6c is loosely fitted to the stopper bolts 8 for restricting the rearward turning range of the top link mounting member 6 protruding rearward from the left and right sides of the bracket 3, and the front side of the plate 6c has the base fixed to the bracket 3. The leaf spring 9 is brought into contact with the spring spring 6b. a
Is a mounting hole for the top link b provided in a plurality of steps on the top link mounting member 6. By the way, the stopper bolts 8 are disposed above and outside the front bracket fixing bolts 4 and 5, and each stopper bolt 8 is provided with a stopper 10 for restricting the forward rotation of the top link mounting member 6. It is hung so that it can swing right and left and slidable in the longitudinal direction. The stopper 10 is composed of a plate 10a having a long hole 11 and a pin portion 10b fixed to the hanging lower end of the plate 10a, and when the stopper 10 is positioned on one side with the bracket fixing bolts 4 and 5 interposed therebetween. The stopper 10 is held in the operating state, and when it is positioned on the other side, the stopper 10 is held in the non-operating state. That is, as shown in FIG. 2, the left and right stoppers 10 are attached to the bracket fixing bolts.
When the stoppers 10 are located inwardly of the bolts 4 and 5, the stopper 10 is held in the stopper action state by the pin 10b abuttingly supported by the heads 4'and 5'of the bolts 4 and 5 by its own weight. When located on the outer side of the fixing bolts 4 and 5, the pin portion 10b
One side of the notch 6'c provided at the bottom of both sides of the plate 6c
It is drooped in a desired state and is held in a non-acting state of the stopper.

By the way, as shown in FIGS. 2 and 3, the stopper 10 is set in a compactly housed state by utilizing the space between the plate 6c and the bracket 3, and it is set whether the stopper is operating or not. Even in such a case, it does not project above the top link attachment member 6. The stopper bolts 4, 5 and the stopper 10 do not necessarily have to be provided on both the left and right sides, and may be provided on one side.

Reference numeral 12 is a draft control rod, one end of which is connected to the top link mounting member 6 by a pin 13 and the other end of which is connected to a select arm 15 by a pin 14. 16 is a draft control lever, 17 is a feedback rod, 18 is a feedback arm, 19 and 20 are links, 21 is a pin protruding from the link 19, 2
2 is select arm 15 and draft control lever 16
Connecting pin, 23 is a connecting pin between the position control lever 2 and the link 19, 25 is a position control lever 24
It is a position control shaft integrated with and also serves as the central axis of rotation of the draft control lever 16. 26 is a mounting pin for the top link b, and 27 is a fender.

When using the draft control for plow work with a tractor, use the left and right stoppers 10
As shown in the phantom line in FIG. 2, the stopper 10 is rotated to the outside of the bracket fixing bolts 4 and 5 and is released, and the stopper 10 is transformed into a vertically hanging state by its own weight, and the pin 10b of the pin portion 10b is lifted. Since one end faces the notch 6'c of the plate 6c and the stopper is in a non-acting state, the action of restricting the forward rotation of the top link mounting member 6 is released, and the work is started in this state (in this case, the lever position is the first position). (At the lever position shown by the solid line in the figure, the hydraulic valve (not shown) incorporated in the hydraulic control device inside the hydraulic case 1 is set to the neutral position). After the work is started, when the thrust in the P direction is applied to the mounting pin 26 from the working machine side via the top link b, the top link mounting member 6 is rotated forward about the pivot pin 7 against the leaf spring 9. Therefore, the draft control rod 12 moves forward and the select arm 15 rotates counterclockwise around the pin 22. At this time, the select arm 15 pushes the pin 21 to link.
19 also rotates in the same direction around the pin 23 and pushes the link 20, so that the feedback arm 18 rotates clockwise around the shaft 18a to move the feedback rod 17 forward.
As a result, the hydraulic valve is switched to the up side, so that the lift arm 2 rotates upward and the working machine rises. When the thrust of the P direction disappears due to the rise of the working machine, the state of FIG. 1 is restored.

When the working machine is lifted, a rearward pulling force is applied to the top link mounting member 6, but this pulling force is received by the stopper bolt 8.

When the draft is used, the stopper 10 is sandwiched between the bracket fixing bolts 4 and 5 and the stopper regulating member 6a, so that swinging due to vibration of the machine body is regulated,
The stopper 10 is stably held at a predetermined position.

On the other hand, when the draft is not used, the left and right stoppers 10 are lifted upward and rotated toward the inside of the bracket fixing bolts 4 and 5, and the pin portion 10b is rotated.
When placed on the heads 4'and 5'of the
Since b is held in a tilted C-shaped inclined posture in which it intervenes between the plate 6c and the bracket 3, forward rotation of the top link mounting member 6 is restricted and draft control is not performed.

When the draft is not used, the stopper 10 is supported by the heads 4 ', 5'of the bracket fixing bolts 4 and 5 by its own weight and is held in a stable inclined state. The middle stopper 10 does not rotate freely to the other side beyond the bolt heads 4'and 5 '.

Effect of the Invention As described above, according to the present invention, the top link mounting member rotatably supported by the machine body is connected to the hydraulic control device, and the compression force applied to the top link is increased by increasing the traction resistance of the working machine. In a draft control device for a tractor, in which a mounting member senses the hydraulic control device to perform a switching operation to raise a working machine, the top link mounting member is attached to the machine body through a bracket fixing bolt in a front-back direction. A stopper that rotatably supports and that restricts the forward rotation of the top link mounting member between the top link mounting member and the bracket is provided to the left and right via a stopper bolt that is provided on the outer side above the bracket fixing bolt. Suspend swingably and slidably in the longitudinal direction, and place the stopper on one side with the bracket fixing bolt in between. The stopper is kept in the working state when it is placed, and is held in the non-working state when it is positioned on the other side, so that the stopper is stably supported both when the draft control is used and when it is not used. In addition, since the mounting height of the stopper bolt and stopper can be set low, even if the seat mounting bracket, tool box, etc. are projected above the top link mounting member, the stopper can be mounted without worrying about the mounting space. It can be easily mounted, and has an effect that the structure is simple and the number of processing steps can be reduced as compared with the conventional one in which the rotation fulcrum of the stopper is provided in addition to the stopper bolt.

[Brief description of drawings]

FIG. 1 shows an embodiment of a draft control device for a tractor according to the present invention. FIG. 1 is a side view of a main part, FIG. 2 is an enlarged rear view of the main part, and FIG. An enlarged side view and FIG. 4 are rear views of a conventional example. In the figure, 1 is a hydraulic case, 2 is a lift arm, 3 is a bracket, 4 and 5 are bracket fixing bolts, 6 is a top link mounting member, 8 is a stopper bolt, and 10 is a stopper.

Claims (1)

[Scope of utility model registration request] Claim: What is claimed is: 1. A top link mounting member, which is rotatably supported by a machine body, is connected to a hydraulic control device, and the top link mounting member senses a compressive force applied to the top link due to an increase in traction resistance of a working machine. In a draft control device for a tractor in which a hydraulic control device is switched to raise a working machine, the top link mounting member is supported rotatably in a front-rear direction with respect to a bracket fixed to a machine body through a bracket fixing bolt. In addition, a stopper for restricting the forward rotation of the top link mounting member between the top link mounting member and the bracket is swingable left and right through a stopper bolt provided on the outer side above the bracket fixing bolt and can be swung laterally. When the stopper is positioned on one side with the bracket fixing bolt sandwiched, it is suspended. There is maintained in the activated condition, the draft control apparatus of the tractor, characterized by being configured to be held in the non-operating state when brought into position on the other side.