JPS6213864Y2 - - Google Patents

Description

[Detailed Description of the Invention] The present invention relates to a steering operation device for a work vehicle such as a tractor, which is required to frequently switch between forward and backward movement for steering. A pivot shaft 11 is held with its axis oriented substantially parallel to the rotational center line of the handle wheel 9 relative to a fixed member 12 that rotatably holds the handle wheel 9. A free end portion 24 of the forward switching lever 8 is disposed near the outer periphery of the handle wheel 9, and the base portion 17 is pivoted so that the free end portion 24 can freely swing in a direction toward and away from the handle wheel 9. An operating position locking member is pivotally supported on the support shaft 11 and is provided between the fixed member 12 and a predetermined eccentric position of the lever 8, and is engaged in the direction in which the free end portion 24 leaves the handle wheel 9. The present invention relates to a mounting structure for a forward/reverse operation lever in a steering operation device for a work vehicle having a configuration in which a removable engagement structure 25 is provided.

This configuration allows the operator holding the handle wheel 9 to easily hold the forward/backward switching lever 8 with his or her fingers and swing the lever, and when this operation is completed, the switching lever 8 is moved to the neutral position by the engagement structure 25. This vehicle has the advantage that it can be maintained at the same time using the handle wheel 9 and that the lever 8 can be used to switch forward and backward movement at the same time, making it easy to steer this type of work vehicle. It is.

However, as a structure for attaching this lever 8 to the pivot shaft 11, a structure as shown in FIG. 4 has been adopted.

In other words, the base of the lever 8 is connected and held to the pivot shaft 11 via the second pivot shaft 18 in a direction perpendicular to the axis of the pivot shaft 11, and the swinging of the lever 8 is restricted as follows. A guide plate 041 having a guide groove 04a through which the eccentric position of the lever 8 is passed is fixed to the fixing member 12 that holds the pivot shaft 11. In this configuration, when the lever 8 is operated to rotate the pivot shaft 11 around the axis, the moment for this rotation acts on the second pivot shaft 18 as a bending force, In addition, because of the above advantages, the lever 8 is rotated rapidly and this acting force tends to act as a sudden force, so the second pivot shaft 18 or its bearing part is easily damaged. It was durable.

Therefore, if the second pivot shaft 18 or its bearing is operated without being aware of damage, there may be a shift between the operating position at the free end or guide plate of the lever 18 and the operating position due to rotation of the pivot shaft. The disadvantage is that there is a risk of the vehicle being moved forward or backward unexpectedly.

The present invention aims to eliminate such drawbacks.

In order to achieve this objective, the mounting structure of the forward/reverse operation lever in the steering operation device for a working vehicle of the present invention is such that the forward/reverse operation lever is mounted on a large diameter boss portion fixed to the pivot shaft, and is attached to a large diameter boss portion fixed to the pivot shaft. A fitting hole into which the base of the lever is fitted is formed in a direction intersecting the axis of the pivot shaft, and has an axis substantially perpendicular to the axis of the pivot shaft and the fitting direction of the fitting hole. The end of the base is pivoted to the back side of the fitting hole by a second pivot shaft, and the width of the fitting hole in the axial direction of the pivot shaft is a range that allows engagement and disengagement of the engagement structure. The base is set to a width that allows it to swing around the second pivot shaft, and the width of the fitting hole in the axial direction of the second pivot shaft is approximately equal to the width of the base in the same direction. This configuration adopts a configuration set to .

With this configuration, the base of the lever is fitted into the insertion hole with a length approximately equal to the diameter of the large-diameter boss portion, and the second pivot shaft is arranged on the back side of this insertion hole and supports the base of the lever. Furthermore, this base is held in contact with the inner surface of the fitting hole in the direction of rotation of the pivot shaft, so the rotational moment of the pivot shaft caused by the lever is applied to the shaft that is inserted into the fitting hole. The force is distributed over substantially the entire length of the base and is transmitted to the pivot shaft, and no longer acts as a bending force on the second pivot shaft.

Therefore, the second pivot shaft and its bearing part are not damaged even if the lever is suddenly rotated, which is the opposite of the above-mentioned advantages of the conventional technology.The durability is improved, and the operating position is We have now been able to eliminate the dangers caused by unexpected fluctuations.

Furthermore, since the durability of the lever has been improved in this way, there is an advantage that the forward/reverse switching operation can be carried out more rapidly and the speed of the steering operation can be improved.

Next, embodiments of the present invention will be described.

First Embodiment (See FIGS. 1, 2, and 3) In this embodiment, a hydraulic front-back switching structure in a tractor shown in FIG. 3 will be described as an example. In this structure, a hydraulic clutch 5 for forward rotation transmission and a hydraulic clutch 6 for reverse rotation transmission are interposed in parallel between an output shaft 2 from an engine 1 and an input shaft 4 of a traveling mission 3. Lever 8 for operating the hydraulic switching valve 7 that selectively switches oil supply to 5 and 6
is arranged near the steering handle wheel 9.

The mounting structure of the lever 8 will be explained in more detail as follows.

A pivot shaft 11 connected to the operating section of the switching valve 7 via a release wire 10 is connected to a handle holder 12 that pivotally supports the wheel 9, with its axis parallel to the center line of rotation of the wheel 9. It is pivoted on one side.

A large-diameter boss portion 15 is integrally fixed to the upper end of the pivot shaft 11, and the lower skirt portion 14 fits over the upper portion of the bearing portion 13 fixed to the holder 12.

This large-diameter boss portion 15 is formed with a fitting hole 16 passing through it in the radial direction.
The base 17 of the lever 8 is fitted into the lever 6 .

At the back end of this fitting hole 16, the base 17 is pivoted by a second pivot shaft 18 that is parallel to a direction perpendicular to the penetrating direction of this fitting hole 16 and the pivot shaft 11. There is.

Further, a protrusion 19 is provided on the base 17 and protrudes downward at a position near the entrance of the insertion hole 16, and is inserted opposite to the protrusion 19 when the lever 8 is in the neutral operation position. blind hole 2
0 is formed on the upper surface of the bearing portion 13, and an engagement structure 25 is provided. A coil spring 21 is interposed between the base portion 17 and the upper wall of the insertion hole 16 to bias the lever 8 in a direction to insert the projection 19 into the blind hole 20.

The widths of the fitting hole 16 and the base 17 in the axial direction of the second pivot shaft 18 are approximately the same, and the width of the fitting hole 16 in the axial direction of the pivot shaft 11 is approximately the same. The base 17 is configured to be able to swing around the second pivot shaft 18 so that the protrusion 19 can be moved in and out of the blind hole 20.

Reference numeral 22 denotes a stopper protrusion that protrudes from the lower surface of the boss portion 15 on the side where the second pivot shaft 18 is provided, and is located within a semicircular notch 23 formed on the upper surface of the bearing portion 13 opposite thereto. The stopper protrusion 22 is movable.

A nib portion 24 is provided at the free end of the lever 8, and this nib portion 24 is disposed close to the lower side of the periphery of the handle wheel 9.

In the embodiments described above, it is possible to change the configuration and target by one or more of the following combinations.

The clutches 5 and 6 are not limited to hydraulic type, but may be electromagnetic type, and the lever 8 is configured to selectively change the electromagnetic operation.

It can be used not only for tractors, but also for transport vehicles, civil engineering construction vehicles, and agricultural machinery such as combines and binders.

The cross-sectional shape of the base 17 is not limited to a circle, but may be various polygons or ellipses. The surfaces facing the left and right side walls of the insertion hole 16 are preferably flat surfaces or curved surfaces with a large radius of curvature.

Instead of the projection 19 and blind hole 20, the engagement structure is constructed by a combination of a guide groove of a guide plate and a lever, as shown in FIG.

The engagement structure 25 is arranged to be locked between the forward operation position and the reverse operation position of the lever 8.

[Brief explanation of the drawing]

The drawings show an embodiment of the mounting structure for the forward/reverse operation lever in the steering operation device for a work vehicle according to the present invention, FIG. 1 is a vertical side view showing the main parts, and FIG. 2 is a cross-sectional view taken along the line of FIG. 1. It is. FIG. 3 is a side view schematically showing a steering operation device, and FIG. 4 is a perspective view showing a conventional example. 9...Handle wheel, 8...Forward/forward switching lever, 11...Pivot shaft, 12...Fixing member, 17
... Base, 15 ... Large diameter boss portion, 16 ... Fitting hole, 18 ... Second pivot shaft, 25 ... Engagement structure.

Claims (1)

[Claims for Utility Model Registration] A pivot shaft 11 is held with its axis oriented substantially parallel to the center line of rotation of the steering wheel 9 with respect to a fixed member 12 that rotatably holds the steering handle wheel 9, A free end portion 24 of the forward/reverse switching lever 8 whose base portion 17 is attached to the pivot shaft 11 is disposed near the outer periphery of the handle wheel 9, and the free end portion 24 is located near and far from the handle wheel 9. The base portion 17 is pivotally supported on the pivot shaft 11 so as to be swingable in a direction of
Between the fixed member 12 and a predetermined eccentric position of the lever 8, there is a releasable engagement structure 25 for locking the operating position, which is engaged in the direction in which the free end 24 leaves the handle wheel 9. In the steering operation position of a work vehicle in which a lever 8 is provided, the base 17 of the lever 8 is attached to the large-diameter boss 15 fixed to the pivot shaft 11 over substantially the entire length of the boss 15 in the radial direction. A fitting hole 16 to be fitted is formed in a direction crossing the axis of the pivot shaft 11, and the axis of the pivot shaft 11 and the fitting hole 1
The end of the base 17 is pivoted to the back side of the insertion hole 16 by a second pivot shaft 18 having an axis substantially perpendicular to the insertion direction of the pivot shaft 1
The width of the fitting hole 16 in the axial direction of the base 17 is within a range that allows the engagement structure 25 to be engaged and disengaged.
is set to a width that allows swinging around the second pivot shaft 18, and the width of the fitting hole 16 in the axial direction of the second pivot shaft 18 is approximately equal to the width of the base 17 in the same direction. A mounting structure for a forward/reverse operation lever in a steering operation device of a work vehicle. The mounting structure for a forward/reverse operation lever in a steering operation device for a work vehicle according to claim 1, wherein the engagement structure 25 is disposed within the insertion hole 16.