JPH0560211U - Lift control device for agricultural tractors - Google Patents

Abstract

(57) [Summary] [Purpose] Provided is a lift control device for an agricultural tractor which is operated by a hydraulic cylinder and can perform position control for vertically moving a lift arm for vertically moving a lower link from the lower link side. To do. An agricultural tractor 1 which is operated by a hydraulic cylinder 11 and is configured to vertically move a lift arm 12 for vertically moving a lower link 7 by a position control arm 15 operated by a position control lever 8. One lift control lever 18 is provided which is connected to the position control arm 15 and can operate the lift arm 15 up and down from the lower link 7 side.

Description

[Detailed description of the device]

[0001]

[Industrial applications]

 The present invention relates to a lift control device for an agricultural tractor, which is operated by a hydraulic cylinder and is capable of performing position control for vertically moving a lift arm for vertically moving a lower link from a lower link side.

[0002]

[Prior Art]

 There is a well-known agricultural tractor in which a position control arm operated by a position control lever operates a lift cylinder for vertically moving a lower link, which is operated by a hydraulic cylinder provided in a tractor body. Then, as shown in FIG. 5, the position control arm A is operated by a position control lever provided near the steering seat of the tractor to move the lower link up and down via the lift arm, and A link rod B is connected to the control arm A so that it can be operated from the lower link side, and a lift arm raising lever C and a lift arm lowering grip D for operating the link rod B are provided. There is known a lift control device in which a position control arm A is pivotally operated by a lift arm lower grip D to vertically move a lower link via the lift arm.

[0003]

[Problems to be solved by the device]

 In the conventional lift control device described above, when the position control arm A is pivotally operated from the lower link side, the link rod B is connected and the lift arm raising lever C and the lift arm lowering grip for operating the link rod B are operated. It has a complicated configuration with D, has a large number of parts, is troublesome to assemble, and has a problem that the device is expensive. The present invention has been made to solve the above problems.

[0004]

[Means for Solving the Problems]

 In order to achieve the above object, the present invention is an agricultural machine which is operated by a hydraulic cylinder, and the vertical movement operation of a lift arm for vertically moving a lower link is performed by a position control arm operated by a position control lever. The tractor is characterized in that it is provided with a single lift control lever that is linked to the position control arm and that allows the lift arm to be moved up and down from the lower link side.

[0005]

[Action]

 With the above-described structure, the agricultural tractor lift control device of the present invention has a simple structure and a small number of parts because one lift control lever that can vertically move the lift arm from the lower link side is connected to the position control arm. The number is reduced, the assembly is easy, the apparatus can be inexpensive, and the operability is good.

[0006]

【Example】

 Hereinafter, an embodiment of the present invention will be described in detail with reference to the accompanying drawings. In FIG. 3, an agricultural tractor 1 has a pair of left and right front wheels 2 and rear wheels 3, an engine part 4 is provided in the front part, and a control part 5, a driver's seat 6, and a lower link 7 are provided behind the engine part 4. A position control lever 8 and the like shown in Fig. 1 are also provided for vertical movement operation. The control section 5, the driver's seat 6, the position control lever 8 and the like are in a cabin 9, a hydraulic lift case 10 is provided on the vehicle body between the left and right rear wheels 3, and the hydraulic lift case 10 is provided in the hydraulic lift case 10. A single-acting hydraulic cylinder 11 shown in the hydraulic circuit diagram of FIG. 1 is incorporated, and the lift arm 12 is rotated in the vertical direction. The lower link 7 that connects the working machine via a link arm 13 is connected to the tip of the lift arm 12.

As shown in FIGS. 1 and 2, a lower end portion of a position control arm 15 is connected to a tip end portion of the position control lever 8 via a connecting rod 14, and a rotation fulcrum of the position control arm 15 is connected to the lower end portion. A control valve 16 (see FIG. 4) for controlling the expansion / contraction operation and stop of the hydraulic cylinder 11 is connected to 15a, and a draft control rod 17 is provided on the position control lever 15 on the position control arm 15 slightly below the pivot 15a. It is connected to the 8 side.

On the side opposite to the side where the position control lever 8 of the position control arm 15 is connected, that is, on the lower link 7 side, a rotation operation plate 19 having one lift control lever 18 fixed is provided with a pivot pin 20. An engagement pin 21 pivotally mounted via the rotary operation plate 19 is engageable with and disengageable from the side edge of the position control arm 15 by the rotation of the rotation operation plate 19. A grip portion 18 a is provided at the tip of the lift control lever 18.

The hydraulic mechanism 22 included in the agricultural tractor 1 will be described with reference to the hydraulic circuit of FIG. 4. The hydraulic mechanism 22 includes a working machine lifting hydraulic mechanism 23 and a power steering hydraulic mechanism 24. is doing. The working machine lifting hydraulic mechanism 23 has a pump P for pumping the oil in the hydraulic tank T to a hydraulic path from the hydraulic tank T to the hydraulic cylinder 11 and a pressure in the working machine lifting hydraulic mechanism 23 is equal to or higher than a predetermined pressure. Relief valve 25 for returning excess oil to the hydraulic tank T when it reaches the limit, pressure oil take-out block 26 for supplying pressure oil to the attachment, etc., and the above-mentioned control for controlling expansion / contraction operation and stop operation of the hydraulic cylinder 11. A valve 16 and a descending speed adjusting valve 27 capable of variably operating the oil discharge path of the hydraulic cylinder 11 are provided in this order.

In the working machine lifting hydraulic mechanism 23, the control valve 16 is switched by the operation of the position control lever 8, and when the position control lever 8 is moved in the upward direction, hydraulic oil is released in the hydraulic cylinder 11. When the piston is supplied and the lift arm 12 connected to the working machine is lifted and the position control lever 8 is moved in the lowering direction, the pressure oil in the hydraulic cylinder 11 is discharged due to the weight of the working machine. The piston contracts and the work machine descends. Further, when the position control lever 8 is shifted to the lock position, the discharge of the pressure oil in the hydraulic cylinder 11 is stopped, and the working machine stops descending and enters the locked state. The lowering speed adjusting valve 27 is also operated by a lowering speed adjusting lever or a knob provided near the position control lever 8.

In the lift control device of the agricultural tractor 1 according to the embodiment configured as described above, the operator normally sits on the driver's seat 6 in the cabin 9 and operates the position control lever 8 to operate the control valve. 16 is switched and the lower link 7 equipped with the working machine is moved up and down through the lift arm 12 to perform the work. However, when the working machine is attached to or detached from the lower link 7, the lower link 7 is slightly moved up and down to hitch. The position needs to be adjusted. However, if only one operator operates the position control lever 8, the working machine cannot be surely attached / detached to / from the lower link 7.

In such a case, according to the present invention, one lift control lever 18 capable of vertically moving the lift arm 12 from the lower link 7 side is connected to the position control arm 15, so that FIG. When the lift control lever 18 is rotated in the arrow direction to the imaginary line position while holding the grip portion 18a, the engagement pin 21 fixed to the rotation operation plate 19 is engaged with the side edge of the position control arm 15. The position control arm 15 is rotated to the imaginary line position by the control valve 16 is switched to supply pressure oil to the hydraulic cylinder 11, and its piston extends to lift the lift arm 12 connected to the working machine. .. From this state, when the lift control lever 18 is pulled in the direction of arrow F, the rotation control plate 19 rotates the position control arm 15 to the solid line position while rotating slightly around the pivot pin 20, and the control valve 16 is rotated. Are switched, the pressure oil in the hydraulic cylinder 11 is discharged by the weight of the working machine, and the working machine descends.

Therefore, the operator can operate the lift control lever 18 while watching the connection state between the working machine and the lower link 7 to finely adjust the height up and down to surely attach / detach the working machine to / from the lower link 7. .. Further, since the lift control lever 18 is pivotally attached to the position control arm 15 via the rotation operation plate 19, the pivot pin 20, and the engaging pin 21, the configuration is simple and the number of parts is small. The assembly is easy, the device can be inexpensive, and the operability is good.

[0014]

[Effect of the device]

 As described above, according to the lift control device for an agricultural tractor of the present invention, one lift control lever, which is connected to the position control arm and is capable of vertically moving the lift arm from the lower link side, is provided. When attaching or detaching the work implement, the lower link can be freely adjusted up and down with one lift control lever to easily attach or detach the work implement. Also, since the lower link can be freely adjusted up and down with a single lift control lever, the structure is simplified and the number of parts is reduced compared to the conventional one provided with a link rod, lift arm raising lever, lift arm lowering grip, etc. It is less and easy to assemble and can be provided at low cost, and also has good operability.

[Brief description of drawings]

FIG. 1 is a side view of an essential part of the present invention.

FIG. 2 is a view from the direction of arrow E in FIG.

FIG. 3 is a partially cutaway side view of an agricultural tractor to which the present invention is applied.

FIG. 4 is a hydraulic circuit diagram.

FIG. 5 is a side view of a conventional example.

[Explanation of symbols]

 1 Agricultural Tractor 2 Front Wheel 3 Rear Wheel 4 Engine Section 5 Control Section 6 Driver's Seat 7 Lower Link 8 Position Control Lever 9 Cabin 10 Hydraulic Lift Case 11 Hydraulic Cylinder 12 Lift Arm 13 Link Arm 14 Connecting Rod 15 Position Control Arm 16 Control Valve 17 Draft control rod 18 Lift control lever 19 Rotation operation plate 20 Pivot pin 21 Engagement pin 22 Hydraulic mechanism 23 Hydraulic mechanism for lifting work machine 24 Hydraulic mechanism for power steering 25 Relief valve control valve 26 Pressure oil take-out block 27 Descending speed Regulating valve

Claims (1)

[Scope of utility model registration request] 1. An agricultural tractor which is operated by a hydraulic cylinder to vertically move a lift arm for vertically moving a lower link by a position control arm operated by a position control lever. A lift control device for an agricultural tractor, which is connected to and provided with one lift control lever capable of vertically moving the lift arm from the lower link side.