JPH0754004B2 - Work tool angle control device for front loader - Google Patents

Description

TECHNICAL FIELD The present invention relates to a work implement angle control device for a front loader.

(Prior Art) A front loader used by being mounted on a vehicle body such as a tractor includes a boom pivotally supported on the vehicle body in a vertically movable manner and a bucket (work implement) pivotally supported at a tip of the boom to be vertically rotatable. )
And a boom control valve for controlling a boom cylinder for moving the boom up and down, and a bucket control valve for rotating the bucket.
The book operation lever enables independent and simultaneous operation.

When scooping earth and sand into a bucket with this type of front loader, if the bucket such as a dump truck is grounded horizontally to the ground,
It is convenient because you can move forward immediately after touching down and scoop up the soil.

Therefore, while using solenoid valves as each control valve, while electrically supporting control signals to the solenoid valves by operating the operating lever,
A control device that detects the angle of the bucket with respect to the boom and automatically returns the bucket control valve to the neutral position when the bucket rotates upward to an angle at which it horizontally descends when it contacts the ground is disclosed in Japanese Patent Application Laid-Open No. 61-221422. (Sho 60-61658) and the like.

(Problems to be Solved by the Invention) The conventional control device has a drawback that the manufacturing cost becomes very high because the electrical control using the solenoid valve is adopted.
Also, when rotating the bucket upward while lowering the boom, it was necessary to continue to hold the operating lever in the operating position for simultaneously lowering the boom and rotating the bucket upward while moving the front loader side. When the vehicle body is retracted, there is a drawback that it requires skill to operate.

In view of such conventional problems, the present invention makes it possible to use an inexpensive manual valve as the control valve and operate the operation lever to the operation position for simultaneously lowering the boom and rotating the work implement upward. After that, even if the hand is released, the boom is automatically lowered and the work tool is rotated to a predetermined angle and stopped to facilitate the control.

(Means for Solving Problems) As a means for solving the problems, the present invention provides a boom cylinder 9 for vertically moving a boom 8 pivotally supported on the vehicle body 1 side and a vertical rotation at a tip of the boom 8. The work tool cylinder 12 that rotates the work tool 11 that is pivotally supported is provided with a control valve that can be operated independently and simultaneously, and one operating lever 14 that operates this control valve is provided with an engagement portion 38. An engaging tool 39 is provided on the vehicle body 1 side that engages and disengages with the engaging portion 38 when the operating lever 14 is set to an operating position for simultaneously rotating the working tool upward and lowering the boom. The detection releasing means 51 is provided for detecting that the hook has become a predetermined angle with respect to the boom 8 and actuating the engaging member 39 in the releasing direction.

(Operation) When the operation lever 14 is operated to the operation position where the boom is lowered and the work tool is rotated upward, the engaging portion 38 engages with the engagement tool 39, and the operation lever 14 is locked at that position. Further, by operating the operation lever 14 at this time, the boom control valve 15 is switched, the boom cylinder 9 is contracted and the boom 8 is lowered, and at the same time, the work tool control valve 16 is switched and the work tool cylinder 12 is contracted. Work implement 11 pivots upward around pivot 10 at the tip of boom 8.

When the work implement 11 rotates to a predetermined angle with respect to the boom 8,
The detection releasing means 51 detects it and operates the engaging tool 39 in the releasing direction. Therefore, the operating lever 14, the boom control valve 15, and the work implement control valve 16 return to neutral, and the boom 8 stops at the lowered position, and at the same time, the work implement 11 automatically stops upward rotation at a predetermined angle.

(Example) Hereinafter, the present invention will be described in detail with reference to the illustrated example.
The figure exemplifies a bucket type front loader mounted on a tractor for use. In FIG. 4, 1 is a tractor body,
Reference numeral 2 is a driver's seat, and 3 is a mount, which are provided on both left and right sides of the tractor body 1.

Reference numeral 4 denotes a front loader, which includes a column 5 that is detachably attached to the mount 3, a brace 6 that projects forward from the column 5 and is detachably attached to the front end of the tractor body 1, and an upper end of the column 5. A boom 8 pivotally supported by a pivot shaft 7, a boom cylinder 9 for vertically moving the boom 8, and a bucket (work implement) pivotally supported by a pivot shaft 10 at the tip of the boom 8. 11 and a bucket cylinder (working tool cylinder) 12 for rotating the bucket 11. In addition, the pillar 5, the brace 6, the boom 8,
A pair of boom cylinder 9 and bucket cylinder 12 are provided on the left and right.

Reference numeral 13 is a control device, of the pair of left and right columns 5, the right column 5
The operating device 13 has a single operating lever 14 and is constructed as shown in FIGS. 1 to 3.

1 to 3, 15 is a boom control valve for controlling the boom cylinder 9, 16 is a bucket control valve (work implement control valve) for controlling the bucket cylinder 12, and these control valves 1
5,16 consists of a spool type 3-position switching valve, and spool 1
7, 18 are fixed to the mounting plate 19 so that they are in the vertical direction. The mounting plate 19 is fixed to the column 5. A control box 20 is fixed to a mounting plate 19 above the control valves 15 and 16. One control lever is provided in the control box 20.
An interlocking mechanism 21 is provided for allowing the control valves 15 and 16 to be operated independently and simultaneously by the control valve 14. The interlocking mechanism 21 includes a first oscillating member 24 and a second oscillating member 25, which are swingable around the axes of a first shaft 22 and a second shaft 23 which are orthogonal to each other.
The operation lever 14 is fixed to. The operating lever 14
Is projected upward from an opening 27 formed in the top plate portion 26 of the control box 20. The first oscillator 24 is U-shaped, has a first shaft 22 in the left-right direction, and the first shaft 22 is a mounting plate.
It is rotatably inserted into a boss portion 29 fixed to a bracket 28 of 19. The first oscillating member 24 has an arm portion 30 projecting forward, and the arm portion 30 includes a pin 31, a rod 32, and a pin.
It is connected to the spool 17 of the boom control valve 15 via 33. The second oscillator 25 is a second shaft in the front-rear direction in the first oscillator 24.
It is pivotally supported by 23, and this second oscillator 25 has a first shaft
It has a protrusion 34 that protrudes in the opposite direction on the axis of 22. The protrusion 34 is connected to the spool 18 of the bucket control valve 16 via the ball receiver 35, the rod 36, and the pin 37. Therefore, the operation lever 14 can be swung in the front / rear lowering / raising directions around the shafts 22 and 23, and right and left squeeze (upward rotation) / dump (downward rotation) directions. 23 Swing 2 around
By the combined movement of 4,25, it is possible to freely swing in each direction in the middle, and each control valve 15, 16 is independently interlocked with the front and rear, left and right operations of this operation lever 14, and it can be operated in the middle direction. The control valves 15 and 16 are designed to work together at the same time.

Reference numeral 38 denotes an engaging portion, which is provided so as to project toward the squeeze direction side in a state of being slightly inclined from the base portion of the operation lever 14 toward the lowering direction side. 39 is an engaging tool, which is a control box
Inverted U-shaped bracket attached to the lower side of the top plate 26 of 20
A vertical axis is rotatably supported by a pivot shaft 41, and a stopper spring 43 is urged upward by a winding spring 42 so as to abut on the top plate 26 side. An upward hook-shaped portion 44 is provided at the tip of the engaging member 39, and as shown in FIG. 5, the operating lever 14 is slightly operated from the neutral position N toward the lowering direction within the lowering operation range a. When only b is operated to the squeeze operation position in the direction of the squeeze, the engaging portion 38 has the hook-shaped portion 44.
It is configured to be engageable with and disengaged from above.

An inner 48 of a push-pull wire 47 is connected to the engagement tool 39 via a pin 45 and a connection tool 46. Further, one end of the outer 49 of the push-pull wire 47 is attached to an outer receiver 49 provided in the control box 20 below the engaging member 39. Therefore, by pulling the inner 48, the engagement tool 39 is rotated around the pivot 41, and the engagement with the engagement portion 38 can be released. The push-pull wire 47 detects that the bucket 11 is at a predetermined angle with respect to the boom 8 and is an engaging tool.
It is interlockingly connected to the detection releasing means 51 so as to operate the 39 in the releasing direction.

As shown in FIG. 6, the detection canceling means 51 includes a rod 53 pivotally supported by a pin 53 on a bracket 52 of the bucket 11 above the pivot 10 and extending along the boom 8, and a play of the rod 53. A guide cylinder 54 that slidably holds the end side, a cam 55 provided on the rod 53, and a cam 55 when the bucket 11 rotates in the squeeze direction to an angle at which the bottom surface 11a of the bucket 11 contacts the ground horizontally. And an L-shaped detection arm 56 which is operated by. The guide cylinder 54 and the detection arm 56 are rotatably supported on the boom 8 by a pin 57. Detection arm 56 cam
The other end of the inner 48 of the push-pull wire 47 is connected to the side opposite to 55, and the other end of the outer 49 is attached to an outer receiver 58 fixed to the guide cylinder 54.

Next, the operation will be described. When the operating lever 14 is operated in the dumping direction at the most raised position of the boom 8, the second oscillating member 25 moves to the second shaft.
It swings around 23 and pulls the spool 18 of the bucket control valve 16 upward via the protrusion 34 and the rod 36, so that the bucket cylinder 12 extends and the bucket 11 performs a dumping action around the pivot 10 to remove soil and sand. discharge.

In the dumped state of the bucket 11, the operation lever 14 is slightly moved downward from the neutral position N in the lowering operation range a, and then the operation lever 14 is operated in the squeeze direction side.
38 engages with the engagement tool 39 from above, and locks the operation lever 14 in the lower operation position and the squeeze operation position. By operating this operation lever 14, the first rocker 24 is moved to the first shaft 22.
It swings around and pushes down the boom control valve 15 via the rod 32, so that the boom cylinder 9 contracts and the boom 8 moves.
Starts to descend, and at the same time, the second oscillator 25 moves the second shaft 23
It swings around and pushes the spool 18 of the bucket control valve 16 downward via the rod 36, so that the bucket cylinder 12 contracts and the bucket 11 rotates upward around the pivot 10.

On the other hand, the rod 53 is pushed backward by the upward rotation of the bucket 11 around the pivot 10, and the cam 55 approaches the detection arm 56 side. When the bucket 11 is rotated to an angle at which the bottom surface can be horizontally grounded, the cam 55 rotates the detection arm 56 to pull the inner 48 of the push-pull wire 47.
39 rotates downward against the spring 42, and disengages from the engaging portion 38. Therefore, the spool 18 of the bucket control valve 16 is pushed upward by the return spring to the neutral position, the bucket 11 stops rotating, and the operating lever 14 returns to the neutral position. By returning the operation lever 14 to the neutral position, the spool 17 of the boom control valve 15 also returns to the neutral position, and the lowering of the boom 8 is stopped.

If the bucket 11 is not grounded in this state, if the operation lever 14 is further lowered, the first shaft 22 is rotated around the first shaft 22.
Since the oscillating member 24 oscillates and pushes the spool 17 of the boom control valve 15 downward via the arm portion 30 and the rod 32, the boom cylinder 9 contracts and the boom 8 descends. Also during this time
Since the bucket 11 is in a stopped state, if the bucket 11 is grounded, the bottom surface 11a is always grounded in a horizontal state.

When you simply squeeze the bucket 11,
It suffices to operate 14 in the squeeze direction as it is from the neutral position N. At this time, the engaging portion 38 does not engage with the engaging tool 39.

By making the lowering operation range C of the above embodiment wider than the lowering operation range C shown in FIG. 7, it is possible to control the bucket 11 to be grounded horizontally during the lowering operation of the boom 8. Become.

The engagement portion 38 and the engagement tool 39 may be provided so as to engage with each other upside down as shown in FIG.

As for the detection releasing means 51, a cam 59 may be provided on the bracket 52 as shown in FIG. 9, and the roller 60 of the detection arm 56 may be operated by this cam 59.

The engagement tool 39 may be operated in the releasing direction by a solenoid 61 as shown in FIG. 10. In this case, a limit switch 62 is provided on the boom 8 side corresponding to the cam 59 as shown in FIG. If the limit switch 62 detects the cam 59, the solenoid 61 may be excited to pull down the engaging member 39.

The work implement may be a fork or the like in addition to the bucket 11.

(Effect of the Invention) According to the present invention, when the operation lever 14 is set to the operation position where the work tool upward rotation and the boom lowering are simultaneously performed, the engaging portion 38
Can engage with the engagement tool 39 to hold the operation lever 14, and even if the hand is released, the work tool 11 can be rotated upward while automatically lowering the boom 8, and the work tool 11 moves to the boom 8. On the other hand, when the predetermined angle is reached, the detection releasing means 51 stops the work tool upward rotation and the boom lowering.
It is possible to perform a quick and easy operation from the dumping work that has been raised to the squeeze work that has been lowered, and the front loader work can be facilitated.

[Brief description of drawings]

1 to 6 show an embodiment of the present invention. FIG. 1 is a sectional side view of a control device, FIG. 2 is a sectional rear view thereof, and FIG. 3 is a sectional plan view. FIG. 4 is a side view of the whole, FIG. 5 is an operation explanatory view, FIG. 6 is a side view of the detection releasing means, FIG. 7 is an operation explanatory view showing another embodiment, and FIG. 8 is an engaging portion. FIG. 9 and FIG. 11 are sectional rear views showing another embodiment of FIG.
FIG. 10 is a side view of the detection releasing means, and FIG. 10 is a sectional rear view showing another embodiment of the control device. 1 ... tractor body, 4 ... front loader, 8 ... boom, 9 ... boom cylinder, 11 ... bucket (work implement), 12 ... bucket cylinder (work implement cylinder), 13
...... Control device, 14 ...... Operation lever, 15 ...... Boom control valve, 16 ...... Bucket control valve (work implement control valve), 21 ...... Interlocking mechanism, 38 ...... Engagement part, 39 ...... Engagement tool , 51 …… Detection release means.

Claims (1)

[Claims] 1. A boom cylinder (9) for vertically moving a boom (8) pivotally supported on the vehicle body (1) side so as to be vertically movable.
And a work tool cylinder (12) that pivots a work tool (11) pivotally supported at the tip of the boom (8) so that the work valve (11) can be operated independently and simultaneously. The engaging portion (38) is provided on one operating lever (14), and the engaging portion (38) is located when the operating lever (14) is in an operating position for simultaneously rotating the work implement upward and lowering the boom. An engagement tool (39) that is engageable with and disengaged with the engagement tool (39) is provided on the vehicle body (1) side, and it is detected that the working tool (11) is at a predetermined angle with respect to the boom (8). 39. A work loader angle control device for a front loader, which is provided with a detection releasing means (51) for actuating 39) in a releasing direction.