JPS6349127Y2 - - Google Patents

Description

[Detailed description of the invention] This invention relates to a three-point link lower link device, and its main purpose is to make it possible to easily and quickly attach and detach work equipment, especially to connect it, and to prevent detachment accidents from occurring. do.

A three-point link type coupling device is widely used as a form of coupling a working machine to the rear of a tractor body. However, in the conventional general three-point link type coupling device, the lower link is pivotally attached to both sides of the tractor body via a pivot shaft so that it can swing up and down, and the intermediate section is connected to the lift rod to lift the hydraulic system. Since the structure is simply connected to an arm, it is difficult to connect the work machine and the work tool.

In other words, because conventional lower links cannot be bent or expanded, unless the connection part (ball joint part) at the rear end is completely aligned with the mounting pin on the work equipment side, the two cannot be connected. , it is necessary to move one side of the tractor and the work equipment to match the other, and no matter which side is moved, it is very complicated to achieve perfect alignment between the two, and it is difficult to connect the work equipment. A big problem arose.

Therefore, we divided the flexible lower link into two parts, the main body part and the movable part, and connected the two parts so that they could expand, contract, and bend.
A device that facilitates handling when connecting a work machine is being considered.

That is, a cylindrical part is provided at the tip of the lower link main body side, and a movable link having a connecting part is fitted into the cylindrical part in a nested structure so that it can be freely moved in and out, and a locking member and a retaining pin are provided at both the extension and retraction positions of the movable link. Some are provided as dedicated parts for each.

However, this increases the number of component parts of the coupling device, resulting in a complicated structure and inconvenience in handling.Furthermore, the lock member easily comes off, resulting in frequent disconnection accidents.

The present invention solves these conventional problems, and embodiments of the present invention will be described in detail below with reference to the drawings.

In FIG. 1, 1 is a tractor body, 2 is a rear wheel, and 3 is a driver's seat. Reference numeral 4 denotes a single-acting 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 device as a working machine, which is attached to the rear of the tractor body 1 via a three-point link 7 and can be raised and lowered by a hydraulic device 4.

The three-point link 7 includes one top link 8 and a pair of left and right lower links 9. Each lower link 9 has a lower link main body 10 and a movable link 12 inserted into a cylindrical portion 11 at the rear end of the lower link main body 10 so as to be extendable and retractable in the longitudinal direction. Pivot shaft 13
and is connected to the lift arm 5 via a lift rod 14. Although not shown, the check chain is connected to the lower link body 10.

In the first embodiment shown in FIGS. 2 to 6,
The cylindrical portion 11 includes a pair of left and right side plates 17 and a pair of upper and lower plates 18 and 19 that connect the side plates 17.
and are combined into a rectangular cylindrical shape, and the rear end is reinforced by surrounding a reinforcing material 20. Further, a notch 21 is provided in the cylindrical portion 11 at approximately the center in the longitudinal direction of the upper edges of the upper plate 18 and the side plates 17, and a lock pin 22 is provided in the notch 21 so as to be freely retractable.

The movable link 12 has sloped parts 23 and 24 formed by cutting out the upper and lower corners of the front end, and an engaged part 25 for locking and for preventing slippage is formed on the rear side of the sloped part 23 on the upper edge side. There is. Furthermore, movable link 1
2 has a connecting portion 27 of a ball joint structure at the rear end, which is detachable from the mounting pin 26 of the rotary device 6.

Reference numeral 28 is a stop pin, which is a headed pin that is supported through a hole 29 formed in the upper rear end of the cylindrical portion 11. This stop pin 28 is located inside the engaged portion 25 and its length is The movable link 12 is allowed to expand and contract within a range of , is engaged with the engaged portion 25.

The hole 29 is slightly larger than the retaining pin 28, and has an arc-shaped guide surface 30 formed from its bottom to the rear, and prevents upward movement when the retaining pin 28 moves from front to rear along the guide surface 30. accompany.

A U-shaped operating tool 33 is supported by the retaining pin 28, and the operating tool 33 is rotatable while straddling the cylindrical portion 11. The operating tool 33 is provided with a gripping rod 34 and a locking pin 22 on the front part, and the locking pin 22 has a diameter larger than the retaining pin 28 and is rotatable relative to the operating tool 33. By doing so, it can move in and out of the notch 21. The notch 21 is slightly larger than the lock pin 22, and a slight play occurs when the lock pin 22 is engaged.

The lower portion of the notch 21 is formed in an arc shape so as to be engaged with the outer periphery of the lock pin 22, and the front portion 25a of the engaged portion 25 is also formed in an arc shape so as to fit the lock pin 22.
The center of curvature of the arcuate surface of the front portion 25a of the 5 is lower than its upper edge.

The lock pin 22 engages with the engaged portion 25 when the movable link 12 is contracted, and prevents the movable link 12 from extending. In this engaged state, the axis B of the retaining pin 28 is located above the axis A of the lock pin 22 by a distance C.

Reference numeral 35 denotes a tension spring tensioned between a pin 36 of the lower link body 10 and a pin 37 protruding from the side of the operating tool 33. It's stretched.

The retaining pin 28, the lock pin 22, and the operating tool 3
3 and tension spring 35 etc., the cylindrical part 1
A locking tool 38 is configured to restrict the expansion/contraction position of the movable link 12 relative to the movable link 12.

The operation of the first embodiment will be explained.

Usually, the movable link 12 is the lower link main body 10
is inserted into the cylindrical part 11 of and is in an extended state,
The retaining pin 28 is engaged with the engaged portion 25 to prevent it from coming off (as shown by the imaginary line in FIG. 4).

When connecting the rotary device 6, the tractor body 1 is moved backward toward the rotary device 6, and then the single-acting hydraulic device 4 is operated in the downward direction to lower the lower link 9 below the mounting pin 26.

Since the movable link 12 has the inclined part 24 at the lower front end and the engaged part 25 on the upper edge side, it can be expanded and contracted and bent upward while being connected to the cylindrical part 11. The longitudinal and vertical positions of the connecting portion 27 are adjusted to correspond to the mounting pins 26 and connected. In this case, the extension of the movable link 12 is restricted by the retaining pin 28 coming into contact with the front portion 25a of the engaged portion 25.

After connecting the left and right connecting portions 27 to the mounting pins 26,
When the tractor body 1 is further moved backward, the movable link 12 contracts into the cylindrical portion 11 while becoming linear with respect to the lower link body 10. At this time,
The inclined part 23 at the front end of the movable link 12 is connected to the lock pin 2.
2 and pushes it up against the tension spring 35. Since the lock pin 22 is rotatable relative to the operating tool 33 and rolls in contact with the inclined portion 23, the movable link 12 is smoothly contracted. When the movable link 12 contracts further, the engaged portion 25 moves to a position facing the lock pin 22, so that the lock pin 22 automatically engages with the engaged portion 25 by the action of the tension spring 35. It comes into the notch 21 as much as possible.

When the lock pin 22 is engaged with the front part 25a of the engaged part 25 (solid line state in FIG. 4), the extension movement of the movable link 12 is blocked by the lock pin 22, and the contraction movement is prevented by the retaining pin 28 when the engagement part 25 is engaged. This is prevented by contacting the rear portion 25b of the portion 25 and by the front end of the movable link 12 contacting the deep portion of the cylindrical portion 11.

In this state, the lower link device is rotary device 6.
However, when a traction load is applied to the movable link 12, the load is applied to the lock pin 22 via the front part 25a of the engaged part 25, and the lock pin 22
is supported by the notch 21.

There is some play in the engagement between the lock pin 22 and the notch 21, and the lock pin 22 moves rearward by the amount of play, comes into contact with the rear part 21a of the notch 21, and is supported by this rear part 21a. As the lock pin 22 moves backward, the retaining pin 2
8 slides on the guide surface 30 and moves rearward and upward, creating a distance C between the axes A and B of both pins 22 and 28. This condition may also occur due to the action of the tension spring 35. That is, even when the lock pin 22 is engaged with the notch 21, the tension spring 35
When a tensile force of 1 is applied, the operating tool 33 assumes an upright shape with the lock pin 22 as a fulcrum, and the retaining pin 28 becomes higher than the lock pin 22.

When the loads of both pins 22 and 28 are supported by the cylindrical portion 11, the axis A of the lock pin 22 is located lower than the axis B of the retaining pin 28, so the lock pin 22 moves downward with the retaining pin 28 as the center. A torque is generated, and a pressing force is generated toward the lower part of the notch 21, which becomes a retaining force that is added to the acting force of the tension spring 35, and the lock pin 22 is reliably prevented from disengaging, thereby preventing the movable link 12 from disengaging. Almost completely preventable. Moreover, this locking force is due to the lock pin 22.
This is only when a traction load is applied to the rotary device 6, and is not applied when the rotary device 6 is attached or detached, so that the lock pin 22 can be easily engaged and disengaged from the notch 21.
Further, since the retaining pin 28 can move slightly back and forth and up and down within the hole 29, the lock pin 22 can be easily engaged and disengaged when no traction load is applied.

7 and 8 show a second embodiment of the present invention, which differs from the first embodiment in the structure of the cylindrical portion 11 of the lower link body 10. A reinforcing plate 40 covering the left and right side plates 17 is welded to the center of the cylindrical portion 11 in the front-rear direction, and a notch 41 corresponding to the notch 21 is also formed in this reinforcing plate 40. This notch 4
1 is formed slightly larger than the notch 21, and does not come into contact with the lock pin 22 when the lower link device starts to be used.

The rear and lower part of the notch 21, which receives repeated loads from the locking pin 22, gradually sag during use and sag inward, causing trouble in the expansion and contraction of the movable link 12, but a reinforcing plate 40 is provided. This creates a droop on the notch 21 side (outside), so that the movable link 12 can always extend and contract smoothly.
Moreover, since the sagging portion of the notch 21 is supported by the notch 41, the support area of the lock pin 22 becomes large and the support becomes strong.

Further, the notch 41 may be made smaller than the notch 21, and the lock pin 22 may be supported by the notch 41 in the initial stage of use of the lower link device; The sagging portion does not occur inside the side plate 17, ensuring smooth expansion and contraction of the movable link 12 and firm support of the lock pin 22.

Hole 42 for supporting the retaining pin 28 shown in FIG.
is a circular hole having a diameter slightly larger than the diameter of the lock pin 28, and its center is located above the axis of the lock pin 22 when it is engaged with the notches 21, 41.
Further, it is preferable that the axis of the retaining pin 28 be higher than the axis of the lock pin 22 even when it is in contact with the lower part of the hole 42.

Similar to the first embodiment, the cylindrical part 11 having this hole 42 is arranged so that the lock pin 22, which receives the traction load from the movable link 12, is located at the rear of the notch 21, 41 in a state where there is no looseness within the notch 21, 41. At the same time, the retaining pin 28 is supported by the hole 42 and positioned above the lock pin 22. As a result, a downward force acts on the lock pin 22 to prevent it from coming off from the notches 21, 41. Note that the hole 42 may be a long hole in the front-rear direction.

According to the present invention described in detail above, the movable link 12 is made telescopic with respect to the cylindrical portion 11, and the movable link 12 can be adjusted to the telescopic position by the retaining pin 28 and the lock pin 22 of the operating tool 33 pivotally supported by the retaining pin 28. Since the structure is configured to restrict the movement, the connection work can be performed simply and easily, and the structure can be simplified by using parts that can be used for multiple purposes. Further, in a state where the lock pin 22 is engaged with the notch portion 21 and the engaged portion 25 to hold the movable link 12 in the contracted state, the axis B of the retaining pin 28 is located higher than the axis A of the lock pin 22. Therefore, lock pin 2
A traction load is applied to both the lock pin 2 and the retaining pin 28, and a downward pressing force is generated on the lock pin 22, that is, the lock pin 22 is engaged by the engaged portion 25.
Disengagement and disengagement accidents of the movable link 12 can be almost completely prevented.

[Brief explanation of the drawing]

1 to 6 show a first embodiment of the present invention, in which FIG. 1 is a usage state diagram, FIG. 2 is an exploded perspective view, FIG. 3 is a plan view, and FIG. 4 is a side view. Figure 5 is a sectional view taken along the - line in Figure 3, and Figure 6 is a - line sectional view in Figure 3.
A line sectional view, FIGS. 7 and 8 show a second embodiment of the present invention, where FIG. 7 is a longitudinal sectional view and FIG. 8 is a perspective view of the lower link body. 9... Lower link, 10... Lower link body, 11... Cylindrical part, 12... Movable link, 21
... Notch, 22 ... Lock pin, 25 ... Engaged portion, 28 ... Stopping pin, 29 ... Hole, 33 ...
Operating tool, 38...Locking tool.

Claims (1)

[Scope of utility model registration request] A notch 21 is formed in the upper part of the cylindrical part 11 at the tip of the lower link main body 10, and the movable link 12 having an engaged part 25 and a connecting part 27 at both ends is connected to the engaged part 2.
A retaining pin 28 is provided which is telescopically fitted into the cylindrical portion 11 from the 5 side and engages with the engaged portion 25 when the movable link 12 is extended on the distal end side of the cylindrical portion 11. An operating tool 33 is pivotally supported on the cylindrical portion 11 via the operating tool 33, and the operating tool 33 is provided with a lock pin 22 that enters the notch 21 and engages with the engaged portion 25 when the movable link 12 contracts. The lower link device is characterized in that the axis B of the retaining pin 28 is located higher than the axis A of the lock pin 22 that is engaged with the engaged portion 25.