JPS6041050Y2 - Tractor lift arm device - Google Patents

Description

[Detailed description of the invention] The present invention relates to a lift arm device for a hydraulic system installed on a tractor.The purpose of the invention is to prevent misalignment of a pair of left and right arms, and to be robust and easy to process and assemble. The goal is to provide something easy.

As is well known, the rear of vehicles such as agricultural tractors has a
A lift arm is provided for raising and lowering the attached work machine.

As a conventional lift arm, for example,
The one described in Japanese Patent No. 809 is known.

This lift arm is provided with a pair of left and right at both ends of the rotation shaft, and one end of the arm is spline-coupled or key-coupled with the rotation shaft, and connected to the work equipment, etc. provided at the other end of the left and right arms. The connecting holes are configured to face each other without misalignment.

The left and right arms are configured to operate integrally when this rotation shaft is rotated by a hydraulic device.

Therefore, the spline or keyway that fits with the rotation shaft, etc.
Since machining accuracy for the connecting holes is required, manufacturing costs increase and assembly accuracy is also required.

Furthermore, since a large force is applied to the joint between the rotating shaft and the arm, breakage is likely to occur at that part.

Furthermore, conventional hydraulic systems require rotational force to rotate the spline shaft.

Furthermore, the hydraulic system is housed within the housing of the aircraft, making maintenance and inspection cumbersome.

Therefore, the present invention was devised to solve the above-mentioned problems.The present invention is characterized by a lift arm device for a tractor in which a pair of left and right arms are rotated by a hydraulic cylinder. The two arms are integrally molded in a substantially U-shape by being connected to each other at a connecting part at the center of rotation, and a hydraulic cylinder is connected to the middle part of the arm.

Hereinafter, embodiments of the present invention will be described in detail based on the drawings.

1 to 3 show a frame type tractor to which the present invention is applied.

In Fig. 1, reference numeral 1 denotes a vehicle body frame, and the front part of the frame 1 is equipped with a freely steerable front wheel (not shown), and the rear part is equipped with a rear wheel 3 that can be freely driven via a differential device 2. has been done.

Further, an engine 4, a seat 5, and other equipment are mounted on the frame 1.

A pair of left and right legs 6' are provided on the frame 1 behind the seat 5 via a rear axle case 2', and a stand 6 is detachably erected on the legs 6'.

The foot arm 7 is rotatably supported on this stand 6.
is installed horizontally between the stands 6 so as to project rearward, and the lift arm 7 is attached to a mounting base 8 projecting from the rear end of the frame 1.
It is driven to be vertically movable by a hydraulic cylinder 9 whose lower part is rotatably supported.

A top link bracket 8' is provided at the center of the vehicle width at the rear of the leg 6' via a mounting member 6''.

In FIG. 2, the lift arm 7 is composed of a pair of left and right arms "10, 10" and a cylindrical connecting part 11, and extends from the outer periphery near both ends of the cylindrical connecting part 11 in the same radial direction. The arm 10 is integrally formed with the connecting portion 11.

A connecting hole 12 is provided coaxially through the distal end of the arm 10.

A pivot shaft 14 passes through the inner hole 13 of the cylindrical connecting portion 11, and both ends of the pivot shaft 14 are connected to the stand 6 through bushes 15.
A male threaded portion 16 having a diameter smaller than the outer diameter of the pivot shaft 14 is provided at both ends of the pivot shaft 14, which is rotatably inserted and supported by the stand and further projects outward from the stand. Movement is regulated.

18 is a spacer between the nut 17 and the stand 6, and
A set screw 19 is provided on the pivot shaft 14 between the stand 6 and the cylindrical connecting portion 11 to ensure relative rotation. ing.

Further, the upper end connecting portion 20 of the hydraulic cylinder 9 is attached to the pin 2 at the lower protruding portion in the middle of one of the left and right arms 10.
It is rotatably supported via 1.

In the above-mentioned embodiment of the present invention, the lift arm 7 is integrally molded, so it is strong and rigid, and does not have a connecting part unlike the conventional one, so that the arm 10 does not shift in position.

In addition, since the connecting holes 12 provided in the arm 10 can be aligned on the same axis by machining, there is no need to process splines, etc. that fit into the rotating shaft as in the past, which reduces manufacturing costs and allows for easy positioning during assembly. There is no need for alignment, making assembly easy.

Next, what is shown in Fig. 3 is a stand 6 and a lift arm 7.
The pivot structure is pivoted by screwing reamer bolts 22 to the lift arm 7 from the left and right outside of the stand 6,
Other aspects are the same as the embodiment shown in FIG. 2 above.

In this case, since the poling process of the connecting portion 11 is not required, manufacturing costs can be reduced, and the outer diameter of the connecting portion 11 can be made small.

Note that the present invention is not only applicable to frame-type tractors, but can also be adopted to tractors with an integral structure type body.

In FIGS. 1, 1 and 2, reference numeral 100 denotes a hitch device which is installed on a plate-shaped mounting member 6'' provided on the rear surface of the vehicle body so that its position can be changed and fixed in the height direction.

A rear wheel fender device 101 is erected via support devices 102 provided on the upper surface of both sides of each rear axle case 2', and a floor sheet 103 is provided between the fender devices 101.

104 is a cabin, and 105 is a three-point link lower link.

In the present invention, the lift arm 7 is connected to the connecting portion 11 between the arms 10.
Since they are integrally molded, the pair of left and right arms 10 will not be misaligned, and will be robust and easy to process and assemble.

In addition, since the hydraulic cylinder is connected to the middle of the arm, compared to conventional systems that connect to the center of rotation,
It can be raised and lowered with a small amount of force.

Therefore, the strength of the hydraulic cylinder itself and the connection strength between the hydraulic cylinder and the arm can be reduced.

Furthermore, since the hydraulic cylinder is connected to the arm, the hydraulic cylinder can be provided so as to be exposed to the outside, which provides excellent effects such as easy maintenance and inspection.

[Brief explanation of drawings]

FIG. 1 is a partially omitted side view showing an embodiment in which the present invention is applied to a frame type tractor, FIG. 2 is a sectional view of the same, and FIG. 3 is a sectional view showing the same embodiment. 7...Lift arm, 10...Arm, 11...Connection part.

Claims (1)

[Scope of utility model registration request] In a lift arm device for a tractor in which a pair of left and right arms are rotated by a hydraulic cylinder, the pair of left and right arms are connected to each other at a connecting portion at the center of rotation, and are integrally molded in a substantially U-shape, and in the middle of the arms. A tractor lift arm device, characterized in that a hydraulic cylinder is connected to the section.