JPS5828486Y2 - Draft control device for agricultural tractors - Google Patents

Description

[Detailed description of the invention] This invention is a draft control device for agricultural tractors, which automatically controls the working equipment such as a rotary tiller or plow when the traction resistance or load on the working equipment towed by the agricultural tractor becomes excessive. This invention relates to a control device for increasing the traction resistance or traction load by an appropriate amount and keeping the above-mentioned traction resistance or traction load constant.

That is, this type of draft control device generally
The link bracket that supports the aba-link in the link device for connecting the work equipment is rotatably supported around the horizontal fulcrum axis, and the load sensor spring for detecting the resistance or load acting on the work equipment is attached to the ring. The link bracket and the hydraulic lift cylinder device for lifting and lowering the work equipment are interlocked and connected by a link mechanism, and the load acting on the load sensor spring and the force of the spring are transmitted through the link bracket. It is configured to automatically move the work machine up and down to balance it.

In such a draft control device, it is rarely known that the load sensor spring is housed in a casing in order to protect the load sensor spring from rainwater and mud and increase its durability.

In addition, in consideration of the fact that depending on field conditions and the type of work equipment, it may be preferable to work under certain conditions rather than sizing the work equipment traction resistance, ・Selectively eliminate the draft control function of the draft control device. In order to make it possible, the following movable locking hardware, that is, a movable locking hardware that is selectively inserted into the gap between the end surface of the link bracket on the body side and a fixed locking surface provided opposite to the end surface, and selectively locks the link bracket. It is also already known to provide movable locking hardware that locks against rotation.

The purpose of this invention is to provide a draft control device that is equipped with a casing and a movable locking hardware as described above, which is made more compact and has a simpler structure by organically relating the arrangement of the various components of the device. There is a plan, and
It is an object of the present invention to provide a novel draft control device for an agricultural tractor, which improves the operability of the movable lock hardware as described above, which is an operated object.

Regarding the illustrated embodiment, the configuration of the draft control device according to the invention will be explained as shown in FIG.
Agricultural tractor body T equipped with a hydraulic lift device consisting of a lift cylinder 1 and a lift arm 3 that is raised and lowered around a fulcrum shaft 2 by the lift cylinder 1.
At the rear, there is an upper link 4 and a pair of lower links 5 on the left and right.
The work machines R and P are connected by the tie rod 6.
A draft control device for equalizing the traction resistance of the working machines R and P, which are raised and lowered by the hydraulic lift device by connecting the lift arm 3 and the lower link 5, is as follows. It is said to have a similar structure.

That is, as usual, this draft control device supports a link bracket 8 which pivotally supports the aba-link 4 at its base end 7R, 7P so as to be rotatable around a horizontal fulcrum shaft 9. A load sensor spring 10 is provided which is compressed by the rotational displacement of
In addition, the link bracket 8 and the operation part of the servo control pulp 11 that switches and controls the supply and discharge of hydraulic pressure to the lift cylinder 1 are interlocked and connected by a link mechanism 12, thereby increasing the traction resistance of the working machines R and P. By utilizing the fact that the link bracket 8 is rotated as shown by the arrow through the rear par link 4, the load sensor spring 10 is compressed and its spring force is increased.
The servo control pulp 11 is displaced via the link mechanism 12 in the lifting direction of the lift cylinder 1 that reduces the traction resistance, thereby establishing a neutral position where the spring force of the load sensor spring 10 and the soil resistance against the work implements R and P are balanced. The draft control device shown in FIG. 1 automatically obtains constant traction resistance of the working machines R and P, and is known from Japanese Utility Model Publication No. 48-21771. Soil resistance L□ for the working machine R etc. when the working machine is a plow P
etc., the soil resistance L2 for the working machine PK is,
Considering the fact that the directions are different as shown in Figure 1 a and b,
In order to be able to use this draft control device regardless of the type of work machine, the link brat 8 is provided with at least one (two in the illustrated case) aba-link support holes 13 and 14 above and below the fulcrum shaft 9. Similarly, Figure 1 a and b
As shown.

When the working machine is a rotary tiller R etc., the upper support hole 13 is used, and when the work machine is a plow P etc., the lower support hole 14 is used to support the aba-link 4 on the bracket 8. Figure 1a.

As shown by arrows indicating the direction of displacement of each member when the resistance increases in b, soil resistance L1. Even though L2 is in a different direction, the link bracket 8 is rotated in the same direction when the resistance increases, that is, the load sensor spring 10 is made to increase in spring capacity equally in both cases, and the servo control pulp 11 is rotated in the same direction. Although the direction of displacement is the same in both cases, this draft control device is further provided with the following mechanism according to this invention.

That is, as shown in FIGS. 2 and 3, it is formed on the back surface of the cylinder case 15 that accommodates the lift cylinder 1 and supports the fulcrum shaft 2, that is, on the surface that is inclined slightly forward and upward as shown. A casing 1 for accommodating the load sensor spring 10 between the cylinder case 15 and the link bracket 80 along a certain back surface.
6 is connected and fixed to the cylinder case 15 by a fixture IT, and is composed of a pair of left and right vertical plate portions 8a and a pair of upper and lower horizontal plate portions 8b that fixedly connect the vertical plate portions 8a. In the link bracket 8, the horizontal support shaft 9 is rotatably supported at both ends of a support tube 18 fixed to the ends of a pair of left and right rear extension portions 16a formed on the casing 16. is rotatably supported around a fulcrum shaft 9, but there is a lock for locking the link bracket 8 so that it cannot rotate, thereby selectively deactivating the draft control device. The means are provided.

That is, the above-mentioned cylinder case 15 has, at its lower end,
The link bracket 8 extends rearward with a slight gap.
Rear extension part 19 facing the horizontal plate part 8b on the lower side of
A lock metal fitting 2 is integrally provided in the gap between the extending portion 19 and the lower horizontal plate portion 8b and abuts against both members 19°8b to lock the link bracket 8 unrotatably.
0 is fixed at the lower end, and the support tube 23 supported by the support member 22 on the back surface of the casing 16 is inserted through the operation rod 21 and is provided along the vertical direction. From this point, the operating rod 21 is raised upwards and the lock hardware 20 is pulled out from the gap between the extension part 19 and the lower horizontal plate part 8b, to the unlocked position shown by the imaginary line in FIG. The operation rod 21 is raised and lowered by holding the upper end knob 21a, so that the draft control device can be selectively deactivated by a non-rotatable lock of the link bracket 8, or activated by releasing the lock. It is being done.

In addition, stopper pins 24 and 25 are fixed to the operating rod 21, and stopper pins 24 and 25 respectively touch the lower end surface and the upper end surface of the support tube 23 to restrict the upper and lower extreme positions of the operating rod 21. The operating rod 21 further has a pin insertion hole 26 for inserting another stopper pin (not shown) that hits the upper end surface of the support tube 23 to prevent the operating rod 21 from moving downward at the unlocked position shown by the imaginary line. It is a provision.

Note that the load sensor spring 10 has a diameter of 5 as shown in FIG.
t/C1 Inside the casing 16, a rod 21 is slidably supported by the casing 16 and has a stopper nut 28 at its upper end that hits the upper surface of the casing 16 and prevents it from entering into the casing 16. 27, and a movable spring receiver 29 for receiving the load sensor spring 10 is fixed to the lower end of the rod 27.

Further, a horizontal cylinder 30 through which the horizontal fulcrum shaft 9 is inserted is fixed to the link bracket 8 between the upper and lower horizontal plate portions 8b.
Although the bin 31 is fixed between the horizontal cylinder 3'0 and the fulcrum shaft 9, a pair of left and right curved arms 32 are fixed at the base end to the horizontal cylinder 30, and the support structure is different from the one described above. The tip of the curved arm 32, which is moved up and down about the axis of the fulcrum shaft 9 as the link bracket 8 is rotated, is inserted into the casing 16 through a window hole formed in the casing 16.
The movable spring receiver 29 faces inside and receives the lower end of the load sensor spring 10, the support shaft 33 and the pin 34.
The movable spring receiver 2 is connected via the curved arm 32 by the rotational displacement of the link bracket 8.
9 is shown so that it can be displaced in a direction that compresses the load sensor spring 10 whose upper end is supported on the inner surface of the top wall of the casing 16.

A stopper hardware 35 is fixed to the middle of the rod 27, which is displaced together with the movable spring receiver 29, for regulating the maximum displacement of the movable spring receiver 29 by abutting against the inner surface of the top wall of the casing 16. The stopper nut 28 has a structure that can be unscrewably locked onto the rod 2T after being screwed an appropriate amount.
1 can be moved forward or backward to change and adjust the load set by the load sensor sling 10.

As described above, when the lock is released by the locking means 20.degree. 21, that is, when the lock hardware 20 is positioned at the position shown by the imaginary line in FIG.

The effect obtained by the illustrated draft control device is the same as that of the conventional one, and according to the illustrated draft control device, the working implement is a rotary tiller R or the like, or a Burary P or the like. By changing the position of the pivot point of the aba-link 4 relative to the link bracket 8 to above and below the fulcrum shaft 9 of the bracket 8, draft control in both cases can be easily achieved with the same device. The draft control device can be selectively deactivated by moving the hardware 20 to the locked position and locking the link bracket 8 unrotatably.

As can be understood from the above description of the embodiments, the draft control device of this invention is provided with a load sensor spring housed in a casing, and a fixing device provided opposite to the fuselage side end surface of the link bracket and the end surface. A movable locking hardware is provided which is selectively inserted into the gap between the link bracket and the locking surface and selectively locks the link bracket against rotation.

This is a draft control device for an agricultural tractor, in which the back surface of a cylinder case 15 of a lift cylinder 1 is formed into a surface that slopes slightly forward and upward, and the casing 16 is aligned with the back surface of the cylinder case 15 and attached to the cylinder case 15. Left and right support portions 16a are connected and fixed and extend rearward from the casing 16.

18 supports a horizontal fulcrum shaft 9 for the link bracket 8, the link bracket 8 is disposed behind the casing 16, and the fixed locking surface is connected to the casing 1.
The movable lock hardware 20 is configured by an end face of an extension part 19 that integrally extends rearward from the cylinder case 15 below the link bracket 8 and is positioned opposite to the lower end face of the link bracket 8. It is fixed to an operating rod 21 which is positioned between the casing 16 and the link bracket 8 between the left and right support parts 16a and 20 and supported so as to be movable up and down, and is operated to move between a lower locking position and an upper unlocking position. The present invention is characterized in that it is configured to be possible, and has the effect of achieving the above-mentioned purpose as follows.

In other words, first of all, if we look at the point of making the device more compact,
A casing 16 that accommodates and protects the load sensor spring 10 is fixedly installed along the back surface of the cylinder case 15, which is formed on a slightly forward and upwardly inclined surface, and is in an inclined position close to a vertical position. Because of this, the front and rear width occupied by the casing 10 is reduced.

In addition, since the front and rear width occupied by the casing 10 is small and an extra space is left behind the casing 10, the draft control device of this invention makes use of such an extra space to move the link bracket 8 to the corresponding part. It is supported by the casing 16 and provided behind it, but as can be seen from FIG. 3, the gap between the casing 16 and the link bracket 8 is such that the casing 16 is tilted slightly forward and upward. As a result, the upper side becomes approximately V-shaped with a large gap in the front-rear direction.

A locking mechanism for unrotatably locking the link bracket 8 in such a roughly V-shaped gap is installed on the end face of the cylinder case extension 19 that constitutes the fixed locking surface so that the gap in the gap is minimized. A movable locking hardware 20 is provided at a lower position of a certain casing 16 so that locking can be performed at the smallest portion in the gap, and an operating rod 21 for moving the locking hardware 20 up and down is extended upward in a larger area in the gap. Considering that the support member that supports the operating rod 21 so as to be movable up and down is disposed in the thick part of the gap, the movable member that locks the link bracket 8 in the small part of the gap. The lock hardware 20 only needs to be small in width, and the operating rod 21 supported by the thick part in the gap can be easily supported, and the draft control device of this invention can be locked using an extremely narrow space. The mechanism is designed to be installed compactly.

Based on the above, the draft control device of this invention is
The casing 16 for protecting the load sensor spring 10 and the link bracket 8 to which the locking mechanism for the link bracket 80 and the lever link are connected occupy a large front-to-back width at the rear of the tractor body where the work implement support mechanism is provided. It is designed to be installed in a compact manner.

Next, in terms of structural simplification, the draft control device of this invention has a casing 16 for protecting the load sensor spring 10 mounted on the rear surface of the cylinder case 15, which is easy to install, and a link bracket attached to the casing 16. 8 is supported, and a locking mechanism is supported between them (operating rod 2 to which movable lock hardware 20 is fixed).
1 may be supported by the casing 16 or the fall of the link bracket 8.

), various mechanisms are supported using the cylinder case 15 as a basic support structure, and after the various mechanisms are assembled to the cylinder case 15 externally, the cylinder case 15 is installed on the tractor body. The structure is simplified to facilitate one-time assembly.

Further, as described above, the operating rod 21 for moving the movable locking hardware 20 is provided so as to be operated from the thick upper side of the approximately V-shaped gap between the casing 16 and the link bracket 8. Therefore, the draft control device of this invention improves the operability of the movable lock hardware 20 for selectively locking the link bracket 8.

[Brief explanation of the drawing]

Figures 1 a and b are schematic mechanical diagrams showing an embodiment of this invention in different usage states, Figure 2 is a plan view of the same embodiment, and Figure 3 is the line ■-■ of Figure 2. FIG. 1...Lift cylinder, 3...Lift arm 4...Aver link, 5...Lower link, 6...Tie rod, 8・・・・・・
・Link bracket, 8b...Horizontal plate part, 9・
...Horizontal fulcrum shaft, 10...Load sensor spring, 15...Cylinder case, 16.
...Casing, 19...Rear extension part,
20...Lock hardware, 21...Operation rod, 21a...Knob portion, 23...Standard, 24.25...Stopper Bin 26...
...Pin insertion hole.

Claims (1)

[Scope of utility model registration request] A load sensor spring is housed and provided in the casing, and is selectively inserted into the gap between the end surface of the link bracket on the body side and a fixed lock surface provided opposite to the end surface to selectively rotate the link bracket. A draft control device for an agricultural tractor is provided with a movable lock hardware that locks the lift cylinder 1 immovably. The cylinder case 15 is placed along the back side of the cylinder case 15.
The left and right support portions 16a, 18 extend rearward from the casing 16 and support the horizontal fulcrum shaft 9 for the link bracket 8, so that the link bracket 8 is attached to the rear of the casing 16 An extension portion 19 is provided, and the fixed locking surface is integrally extended rearward from the cylinder case 15 below the casing 16 and is positioned opposite to the lower end end surface of the link bracket 8.
The lower end of the operating rod 21 is configured such that the movable lock hardware 20 is positioned between the casing 16 and the link bracket 8 between the left and right support portions 16 at 20 and supported so as to be movable up and down. A draft control device is characterized in that it is configured to be fixed to a position and to be movable between a lower locking position and an upper unlocking position.