JPS6327526Y2 - - Google Patents

Description

[Detailed Description of the Invention] The present invention relates to a lower link of a three-point linkage mechanism for towing and mounting a working machine such as a rotary tiller or a plow on a moving vehicle such as a tractor.

In order to facilitate the connection between the lower link and the working machine, the lower link 9 is divided into front and rear halves, as shown in FIG. 10, so that the first link 10 and the second link 12 can be moved relative to each other in the longitudinal direction. After the second link 12 is connected to the working machine by being configured to allow slight vertical swinging, both links 10 and 12 are contracted, and the lock member 20 provided on the first link 10 and the second link 1 are retracted.
By engaging the notch 23 provided in 2, both links 1
A lower link 9 has been devised that prevents movement of 0 and 12.

In this lower link 9, both links 10,
There is some play in the contracted state of 12, and the 1st and 2nd
When tensile and compressive loads are repeatedly applied to the links 10 and 12, the engaging surface 29 of the lock member 20 and the engaged surface 24 of the notch 23 collide, and as shown in FIG. 29 is getting tired.

If the engaging surface 29 and the engaged surface 24 are parallel to the axis of the locking member 20, they will become inclined with respect to the axis when settling occurs, and when a tensile load is applied, the locking member 20 will be pushed up. A force α may be generated, and the second link 12 may come off naturally.

In view of these problems, the present invention provides a protrusion on the engaged surface of the notch at a position spaced apart from the bottom surface thereof, and places this protrusion at a location remote from the end of the engagement surface of the lock member. It is an object of the present invention to provide a lower link which does not form an inclined surface that would generate a force to push up a lock member even if the lower link sag by being configured to abut against each other.

The features of the present invention to achieve this purpose are that the lower link that connects the working machine to the moving vehicle is divided into two parts, front and rear, and the first link has a cylindrical part at the end and can move freely into and out of the cylindrical part. and a locking member,
The lower link is provided with a notch that can be engaged with a lock member to prevent movement of the second link, the end of which is fitted within the cylindrical portion so as to be relatively movable in the longitudinal direction, A protrusion protruding toward the lock member is formed on the engaged surface of the notch that faces the engagement surface, and this protrusion is spaced apart from the intersection of the engaged surface and the bottom surface of the notch, and The point is that it is formed at a position where it comes into contact with a portion of the engagement surface that is remote from the distal end surface of the member.

The invention will now be described in detail with reference to the illustrated embodiments.

In the first embodiment of the present invention shown in FIGS. 1 to 4, 1 is a tractor body, 2 is a rear wheel, and 3 is a driver's seat. Reference numeral 4 denotes a hydraulic system mounted on the rear part of the tractor body 1, which has a pair of left and right lift arms 5. Reference numeral 6 denotes a rotary tiller as a working machine, which is attached to the rear of the tractor body 1 via a three-point linkage mechanism 7, and can be raised and lowered by a hydraulic device 4.

The three-point link mechanism 7 includes one top link 8 and a pair of left and right lower links 9. Each lower link 9 includes a lower link main body 10 (first link),
The lower link body 10 has a movable link 12 (second link) inserted into the cylindrical portion 11 at the rear end so as to be freely retractable in the longitudinal direction. It is pivotally supported and connected to the lift arm 5 via a lift rod 14. Of course, the check chain is also connected to the lower link body 10.

As shown in FIGS. 2 to 4, the cylindrical portion 11 is formed by combining a pair of left and right side plates 15 and a pair of upper and lower plates 16 and 17 connecting the side plates 15 into a rectangular cylindrical shape. , the rear end is a U-shaped reinforcement 18
It is reinforced from the top and bottom respectively.

Further, a holding cylinder 19 is provided in the cylindrical portion 11 in a protruding manner at a position slightly deviated forward from the longitudinal center of the upper plate 16, and a locking member 2, which will be described later, is attached to this holding cylinder 19.
0 is held in the cylindrical portion 11 so as to be able to move forward and backward.
The movable link 12 has sloped parts 21 and 22 formed by cutting out the upper and lower corners of the front end, and a longitudinal notch 23 is formed at the rear of the sloped part 21 on the upper edge side. A surface portion standing up from the bottom surface 23a is an engaged surface 24 for a lock, which will be described later.

Further, the movable link 12 has a connecting portion 26 having a ball joint structure at the rear end, which is detachable from the mounting pin 25 of the rotary tiller 6 . Reference numeral 27 denotes a retaining pin, which is driven into the rear end of the upper side of the cylindrical portion 11 so as to span between the side plates 15. The movable link 12 is engaged with the notch 23 so as to allow the movement and to bend and swing only above the straight position with respect to the lower link body 10 when the movable link 12 protrudes rearward.

As shown in FIG. 2, the locking member 20 has flat surfaces 28 on both left and right sides, and these flat surfaces 28
5, the engagement surface 29 is unrotatable between the side plates 15 and can be freely inserted and removed, and also has an engagement surface 29 that is in surface contact with the engagement surface 24 at the front end of the notch 23 in a detachable manner. 35 is a push-up surface that comes into contact with the inclined portion 21 when the movable link 12 is inserted. Lock member 20
has a shaft portion 31 which is vertically slidably fitted into the holding cylinder 19 and vertically slidably fitted into the lid body 30 screwed onto the upper end of the shaft portion 31.
A gripping ring 32 is provided at the upper end of the holder.

Further, the lock member 20 is biased downward by a coil spring 33 interposed between the lock member 20 and the lid body 30. A protrusion 30a is formed concentrically on the lower surface of the lid 30 so as to surround the shaft 31 of the lock member 20, and the protrusion 30a has a sufficient guide portion for the shaft 31. , to prevent misalignment, etc., and to set the upper limit of the locking member 20.
The lower end is regulated so as to be substantially flush with the upper plate 16 of the cylindrical portion 11. 34 is a reinforcing rib.

The movable link 12 is formed of a rectangular iron plate having a rectangular cross section, and has inclined portions 21, 22 and a cutout portion 23 formed by fusing. The intersection A between the bottom surface 23a of the notch 23 and the engaged surface 24 is approximately a right angle in the one shown in FIG. It was easy to cause sagging as shown in FIG. 11.

In the present invention, an arcuate recess 3 is further added to this intersection A.
7, and a protrusion 38 is formed at a position spaced apart from the intersection A of the engaged surface 24. Therefore, intersection A is a virtual point. As shown in FIG. 2, the engagement between the locking member 20 and the notch 23 is such that the end surface 20a of the locking member 20 is close to the bottom surface 23a of the notch 23, and the protrusion 38 is in a position upwardly away from the end surface 20a. The lower part of the engaging surface 29 only faces the recess 37 and does not come into contact with the engaged surface 24 .

Therefore, when a tensile load is repeatedly applied to the movable link 12, the protrusion 38 collides with the engagement surface 29 and deforms both, but the deformation of the protrusion 38 subsides so that the amount of protrusion decreases. The engaging surface 29 is recessed at the portion where the protrusion 38 comes into contact, and regardless of which deformation occurs or both deformations occur, since the recess 37 exists, the inclined shape shown in FIG. 11 is formed. The locking member 20 does not loosen.
There is no possibility that the movable link 12 will be pushed up by the engaged surface 24 and the movable link 12 will naturally separate.

FIG. 5 shows a second embodiment of the present invention, in which the recess 37 of the notch 23 has a triangular shape, and therefore a trapezoidal protrusion 38 is formed on the engaged surface 24. . In this embodiment, as in the previous embodiment, the locking member 20 is pushed only by the protrusion 38 becoming flattened or the engagement surface 29 being dented as shown by the imaginary line due to repeated tensile loads. There are no slopes that raise the surface. Note that the other configurations are the same as in the first embodiment.

6 and 7 show a third embodiment of the present invention, in which a rectangular recess 37 is formed in the notch 23 of the movable link 12, and a rectangular or trapezoidal protrusion is formed in the engaged surface 24. A portion 38 is formed, and this protrusion 38 abuts the middle portion of the engagement surface 29 of the locking member 20, so that the natural pushing up of the locking member 20 can be prevented in the same manner as in the previous embodiment.

The distal end portion 12a of the movable link 12 has a vertical width narrower than the midway portion, and has a gap B between it and the upper plate 16. By providing this gap B, it becomes possible to disengage the lock member 20 from the movable link 12 without completely pulling it out from between the side plates 15, 15, and prevent rotation when the lock member 20 is pulled up from the flat surface. This can be achieved by the lower part of 28 being in contact with the side plates 15, 15.

The reason why the locking member 20 is prevented from rotating when it is pulled up is to ensure that the locking member 20 performs its locking function. When the movable links 12 come into contact with each other, when a tensile load is applied to the movable link 12, the locking member 20 is naturally pushed up, and the movable link 12 cannot be prevented from moving.

As shown in FIG. 10, the locking member 20 is prevented from rotating even if the locking member 20 is pulled up.
6 and the engagement surface 29, but in this structure, the holding cylinder 19
cannot be fitted into the upper plate 16, and the end of the upper plate 16 must protrude into the holding cylinder 19.
Therefore, the end portion 19a of the holding cylinder 19 must be milled, which increases the cost.

Therefore, as shown in FIG.
If the tip end 12a of the holding tube 19 is made narrow, the holding tube 19
Even if the lock member 2 is inserted into the upper plate 16,
0 is pulled up to a higher position than the tip 12a,
The lower part of the flat surface 28 can be kept in contact with the side plate 15, and this contact can prevent the lock member 20 from rotating. Therefore, there is no need to process the holding cylinder 19, and the movable link 12 can be formed by a simple process of fusing and cutting, and the rotation prevention structure of the locking member 20 can be easily formed.

Further, the vertical widths of the flat surface 28 and the engaging surface 29 of the locking member 20 are long enough to correspond to the depth of the notch 23, and when the locking member 20 is in the engaged state, the tip end surface 20a of the locking member 20 abuts the bottom surface 23a, and the locking member 20 oblique plane 28 of
The upper circular portion 20b is configured so as not to come into contact with the side plate 15, so that even if the lock member 20 is twisted due to the tensile load of the movable link 12, the circular portion 20b
0b will not hit the side plate 15 and cause burrs on the upper edge of the side plate 12, and therefore there is no risk that the locking member 20 will malfunction due to such burrs.

Further, in this third embodiment, a conical spring is used as the coil spring 33, and when the locking member 20 is pulled up and the coil spring 33 is compressed, its dimension is shorter than that of a cylindrical spring. Shortened or circular portion 20 of locking member 20
The axial length of b can be increased.

8 and 9 show a fourth embodiment of the present invention, in which a recess 37 of a cutout 23 of a movable link 12 is shown.
has a triangular shape as in the second embodiment, and the engagement surface 29 of the locking member 20 is formed with a protrusion 39 that fits into the recess 37, and the protrusion 38 fits into the engagement surface 29.
At the same time, the recessed portion 37 and the convex portion 39 abut against each other, and the engaging surface 29 abuts the entire surface of the engaged surface 24 . According to this embodiment, even if the engaging surface 29 and the engaged surface 24 undergo fatigue due to repeated tensile loads, the contact surfaces of the concave portion 37 and the convex portion 39 are inclined in the direction in which the locking member 20 is pulled down. Therefore, the first
The locking member 20 is not pushed up as shown in FIG. However, in this embodiment, when releasing the action of the locking member 20, the movable link 12 must be pushed slightly into the lower link body 10.

The shaft portion 31 of the locking member 20 is divided into upper and lower halves, which are pivotally connected via a pin 40, and this pin 40 is located in a direction crossing the movable link 12.

When the locking member 20 is engaged with the movable link 12, it receives the tensile load of the movable link 12 and C
A moment is applied to the shaft portion 31 in the D direction around the point, and the shaft portion 31 may bend due to the reaction force from the lid 30, making it difficult to pull it up. To solve this problem, the diameter of the through hole 30b of the lid body 30 may be increased, but this imposes restrictions on the setting of the coil spring 33.

Therefore, as described above, if the shaft portion 31 is divided into upper and lower halves and the lower shaft portion 31a is made unrotatable about the horizontal axis with respect to the upper shaft portion 31b, the lock member 20 will not be distorted by the tension of the movable link 12. Also, the upper shaft portion 31b
does not bend, and the lock member 20 can always be moved up and down easily.

According to the present invention detailed above, the second link 12
A locking member 20 is provided on the engaged surface 24 of the notch 23.
A protrusion 38 protruding to the side is provided, and the protrusion 38 is located at a position where the intersection A between the engaged surface 24 and the bottom surface 23a is separated from the lock member 2.
Since the locking member 20 comes into contact with a portion of the engaging surface 29 that is distant from the distal end surface 20a of the locking member 20, even if the protruding portion 38 becomes flat and the engaging surface 29 is deformed due to the tensile load applied to the second link 12, the locking member 20 The locking member 20 and the notch 23 are always in a normal state of engagement, and natural separation of the second link 12 can be reliably prevented. The durability of the lower link 9 can be improved.

[Brief explanation of the drawing]

1 to 4 show a first embodiment of the present invention, in which FIG. 1 is an overall side view showing the state of use, FIG. 2 is a cross-sectional side view of the main parts, and FIG. X-
An X-ray cross-sectional view, Figure 4 is a Y-Y cross-sectional view of Figure 2,
FIG. 5 is a sectional view showing the main parts of the second embodiment, FIG. 6 is a sectional view showing the main parts of the third embodiment, and FIG.
8 is a sectional view showing the main parts of the fourth embodiment, FIG. 9 is a sectional view taken along the SS line in FIG. 8, and FIG. 10 is a comparative example of the present invention. The cross-sectional view shown in FIG. 11 is an explanatory diagram showing the main parts of a comparative example. DESCRIPTION OF SYMBOLS 1... Tractor body, 9... Lower link, 10... Lower link body (first link), 11... Cylindrical part, 1
2... Movable link (second link), 20... Lock member, 20a... Tip surface, 23... Notch, 23a... Bottom surface, 24... Engaged surface, 29... Engaging surface, 37... Recess, 38... Projection .

Claims (1)

[Scope of utility model registration request] Lower link 9 connecting work machine 6 to mobile vehicle 1
A cylindrical portion 11 and a locking member 20 that can move forward and backward into the cylindrical portion 11 are provided at the end of the first link 10, and a locking member 20 is provided inside the cylindrical portion 11 so as to be relatively movable in the longitudinal direction. The lower link is provided with a notch 23 that can be engaged with the locking member 20 to prevent the second link 12 from moving, the notch facing the engaging surface 29 of the locking member 20. Part 23
A protrusion 38 protruding toward the locking member 20 is formed on the engaged surface 24 of the notch 23, and this protrusion 38 is spaced apart from the intersection A between the engaged surface 24 of the notch 23 and the bottom surface 23a, and Tip surface 20 of member 20
A lower link characterized in that it is formed at a position that abuts a portion of an engagement surface 29 that is remote from a.