JPH0724431Y2 - Boom type hydraulic working equipment hydraulic operating device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION (Industrial field of application) The present invention relates to a hydraulic operating device for a boom hydraulic working machine.

(Prior Art) For example, in a front loader equipped with a bucket as a work tool, when the boom is raised after scooping earth and sand with the bucket, even when the bucket is in a substantially lifting posture with the opening of the bucket facing upward, As the boom rising angle increases, the bucket becomes backward and downward, and the scooped sand and sand falls on the hood side of the traveling vehicle.

Therefore, conventionally, a sensor for detecting the lifting posture of the bucket and a sensor for detecting the raising angle of the boom are provided, and the posture of the bucket is electrically detected according to the raising of the boom to control the bucket cylinder control valve. Is controlled via a solenoid valve to correct the bucket posture by the operation of the bucket cylinder to a posture in which the earth and sand do not spill.

In addition, in the front loader, there is a case where the loader is lifted to enter the work under the loader, and at this time, a check member that restricts only the lowering direction and the dumping direction is provided so that the operation lever does not operate accidentally. Some have secured safety.

(Problems to be Solved by the Invention) According to the conventional electrical horizontal holding technique, it is difficult to improve reliability by requiring expensive electric components such as two detection sensors and solenoid valves. It was

Therefore, it is possible to feed back the boom raising operation from the state in which the work implement is in a substantially lifting posture to the control valve of the work implement cylinder by the link mechanism so as to mechanically maintain the substantially lifting posture of the work implement. Recommended.

However, when this mechanical horizontal holding technology is adopted, the restraining member regulates the dumping direction, the squeezing direction, and the lowering direction.When the operating lever is raised in this state, the link mechanism works to raise the boom. Is fed back to the operation lever as a downward direction and is regulated, so that the link mechanism or the operation lever may be damaged.

It is an object of the present invention to prevent damage to an operation lever and the like even when mechanically holding the product horizontally.

(Means for Solving the Problem) According to the present invention, the boom 7 can be moved up and down via the lift cylinder 11, and the work implement 9 attached to the boom 7 can be tilted via the tilt cylinder 12. The boom type hydraulic working machine 1 is provided with control valves 34 and 35 for controlling the lifting cylinder 11 and the tilt cylinder 12, respectively.
In order to achieve the above-mentioned object, the following technical measures are taken in a hydraulic operating device in which 4,35 can be operated independently and simultaneously by one operating lever 40.

That is, the present invention provides a link mechanism R that feeds back the upward movement of the boom 7 from the state in which the working tool 9 is in the substantially lifting posture to the control valve 35 of the tilt cylinder 12 to maintain the working tool 9 in the substantially lifting posture. The control box 41 of the operating lever 40 is provided with a restraining member 52 for restraining the raising operation U, the lowering operation D and the dumping operation T of the operating lever 40 so as to be movable in the left-right direction and rotatable. It is a feature.

(Embodiment and Operation) Hereinafter, an embodiment and operation of the present invention will be described with reference to the drawings.

In FIG. 6, reference numeral 1 is a boom type front loader mounted on the front part of the tractor 2, and a pair of left and right mounting bases 4 are mounted on the traveling vehicle body 3, and a mast 5 is detachably fixed to each upper part thereof. The left and right booms 7 are pivotally supported on the upper part of the mast 5 via pivots 6, and one bucket (work implement) 9 is pivotally supported on the tip of each boom 7 via pivots 8. There is.

The booms 7 are paired on the left and right, and the middle part in the front-rear direction is bent. The rear part from the bent part to the mast 5 and the front part from the bent part to the bucket 9 are formed in a substantially straight line. There is.

The bucket 9 has an opening 9a at the front in the state shown by the solid line in FIG.
In addition to a bucket, a fork, grader, backhoe bucket, or the like can be used as the work tool.

An elevating cylinder 11 for raising and lowering the boom is provided between the midway portion of the boom 7 and the lower portion of the mast 5, and a tilt cylinder 12 for performing the scooping operation and the dumping operation of the bucket is provided between the boom 9 and the bucket 9. The lower part of the left and right brackets 13 fixed to the back of the bucket 9 is connected to the boom 7, and two links 1 are formed between the upper part of the bracket 13 and the boom 7 to form a four-bar linkage 14 with them.
Each end of 5,16 is connected. The other ends of the two links 15 and 16 are flexibly connected by a connecting pin 17, and the rod of the tilt cylinder 12 is connected to the connecting pin 17. The four-bar linkage 14 is provided to increase the maximum rotation angle of the bucket 9.

In the front loader 1, the bucket control valve is dumped in a dumping direction via a link mechanism provided between the bucket 9 and the control valve of the cylinder 12 for raising the boom 7 from a state in which the bucket 9 is in a specific posture. There is provided a work implement attitude control device configured to maintain the specific attitude of the bucket 9 even when the boom 7 is lifted by converting the operation to the operation. Next, this device will be described in detail.

A support plate is provided at a midway portion of one of the left and right booms 7 in the longitudinal direction.
18 is fixed, and a horizontal shaft 19 for mounting the bucket cylinder 12 is provided on the support plate 18. An end portion of the horizontal shaft 19 projects laterally from the support plate 18 and has a shaft end portion 2 Arms 21 and 22 of the book are supported so as to be rotatable relative to each other.

The horizontal axis 19 for supporting the arms 21 and 22 is also used as the horizontal axis 19, but it may be separately prepared and provided on the support plate 18 or in the middle of the boom so as to project laterally.

The second arm 22 is located closer to the support plate 18 than the first arm 21,
A backing plate that forms an engaging portion 25 that can come into contact with the first arm 21 is fixed to the side edge thereof. Further, one end of a rod 26 (second connecting member) is connected to the tip of the second arm 22, and the other end of the rod 26 is pivotally connected to a link 15 pivotally supported by the boom 7. The second arm according to the scooping operation and the dumping operation of the bucket 9 via the 16 and the rod 26.
22 is rotated to detect the attitude of the bucket 9. The front end of the rod 29 (first connecting member) is connected to the tip of the first arm 21. The rod 26 is substantially along the side surface of the front portion of the boom 7, and the rod 29 is substantially along the side surface of the rear portion of the boom 7.
Is protected by the boom 7.

A mounting plate 33 for the control mechanism 32 is mounted on the upper rear surface of the mast 5 as shown in FIGS.

In FIG. 7, E is an engine equipped with a tractor, and P is a hydraulic pump driven by this engine. 34 is a control valve for controlling the lifting cylinder 11, 35 is a tilt cylinder
It is a control valve that controls 12.

36 is a main relief valve, 37 is a check valve, 38 is a sub relief valve connected to the lift circuit of the lifting cylinder 11, and operates at a higher pressure than the main relief valve 36. The sub relief valve 38 is connected to the tank. 39 is a lifting cylinder 11
It is a check valve connected to the down circuit of and communicates with the tank.

These control valves 34, 35 are spool type three-position switching valves, and as shown in FIGS. 3 and 4, the spools 34a, 35a are fixed to the mounting plate 33 so as to be in the vertical direction. The return springs 34b and 35b return the spools 34a and 35a of the control valves 34 and 35 to the neutral position. The neutral position return spring may be provided on the operation lever 40.

41 is a control box, as shown in FIGS.
It is fixed to the mounting plate 33 above 4,35 and supports one operation lever 40 and forms a lever guide portion 42. The control box 41 has a U-shaped bracket 43 in plan view.
Is fixed, and the first shaft 45 in the left-right direction fixed to the first oscillator 44 is pivotally supported on the bracket 43, and the second oscillator 46 is arranged in the U-shaped portion of the first oscillator 44. Second axis 47 in the front-back direction
The first shaft 45 and the second shaft 47 have their axes orthogonal to each other.

The base of the operating lever 40 is fixed to the second oscillating member 46, and the axis of the second oscillating member 46 is orthogonal to that of the second oscillating member 46 so that the second oscillating member 46 can be concentric with the first shaft 45. Two shaft portions 48, 49 are provided so as to project left and right, and are connected to the spool 35a of the bucket control valve 35 via the ball joint and rod of the first shaft portion 48, and the second shaft portion 4
9 is a swing member 28 via a transmission body 50 such as a rod or a wire.
It is connected to the rear end via a pin 51.

The first oscillating member 44 has an arm portion 44a protruding forward, and this arm portion 44a is connected to the boom control valve 3 via a joint and a rod.
It is connected to four spools 34a. The rod is screwed into the joint so that its length can be adjusted.

The control mechanism 32 rotates the single operating lever 40 in the vertical direction to swing the first rocker 44 about the first shaft 45 and pushes the spool 34a of the boom control valve 34 up and down. Pull,
The boom cylinder 11 is operated to move the boom 7 up and down (in FIG. 2, D is lowered and U is raised). When the operation lever 40 is rotated in the left-right direction, the second oscillating member 46 is oscillated about the second shaft 47, and the spool of the bucket control valve 35 is rotated.
35a is pushed up and down and the bucket cylinder 12 is operated to rotate the bucket 9 up and down (in FIG. 2, S indicates the squeeze direction, and T indicates the down direction). In addition, operating lever 40
When the lever is operated at an angle, both control valves 34 and 35 can be operated at the same time, and the boom 7 can be moved up and down and the bucket 9 can be rotated up and down at the same time, and the operating lever 40 can operate both control valves 34 and 35 independently. It can be operated simultaneously.

When the operation lever 40 is rotated left and right, the second rocker 46
Swinging causes the swinging member 28 to swing through the transmission body 50,
The first arm 21 is swung via the rod 29.

In the embodiment, the bucket control valve 35 is set so as to rotate the bucket 9 upward when the spool 35a is pushed downward, that is, to perform the rake operation, and to dump the bucket when pulled upward. There is.

In FIG. 1, a support shaft 30 is projected from the upper portion of the mast 5, and the support shaft 30 is pivotally supported by first and second swing members 28a and 28b having an L-shape in a side view. A rod 29 is connected to one end of the first swing member 28a via a pin 51A, and a second swing member 2
One end of 8b is connected to the transmission body 50. The other ends of the first and second oscillating members 28a and 28b are superimposable with each other, and in the superposed state, they act as a single bell crank oscillating member 28.

That is, the first and second swing members 28a, 28b transmit the movement of the rod 29 to the second shaft portion 49 via the transmission body 50.

That is, on a flat ground, the bucket 9 can perform a scooping operation and a dumping operation from a scooping posture in which the bottom surface is horizontal. After scooping earth and sand, the bucket cylinder 12 is contracted to prevent the earth and sand from falling. Makes a scooping motion until it reaches a horizontal position. The bucket 9 can be turned upward at the grounding position where the boom 7 is lowered until the opening 9a is slightly rearward, but when the soil is lifted, the opening 9a is set to a substantially horizontal position, that is, a specific position. To be done.

When the bucket 9 has a substantially specific posture at the ground contact position,
The arm 22 rotates so as to approach the first arm 21, and the engaging portion
25 is close to the first arm 21. When the boom cylinder 11 is extended from that state and the boom 7 is raised and rotated about the pivot 6, the horizontal shaft 19 moves upward about the pivot 6 and the rod 29 moves upward about the pin 51A. , The distance from the horizontal shaft 19 to the pin 51A becomes longer, and the first arm 21 relatively rotates in the clockwise direction in FIG. 1 about the horizontal shaft 19, which causes the first arm 21 to move to the Two
It contacts the engaging portion 25 of the arm 22. From that state, the first arm 21 is restricted from moving in the clockwise direction in FIG. 1 by the second arm 22, and becomes immobile unless the bucket cylinder 12 is operated. Therefore, the first and second arms 21, 22 and the rods 26, 29, etc. The link mechanism R is stationary with respect to the boom 7.

The distance from the horizontal axis 19 to the pin 51A further extends while the boom 7 further rises and shifts to the rising posture shown by the dashed line in FIG. However, the first arm 21 remains immovable because it is in contact with the engaging portion 25, so that the swing member 28 is relatively swung counterclockwise in FIG. The second oscillating member 46 is oscillated, whereby the spool 35a is pulled up and the bucket control valve 35 is forcibly dumped.

This dumping operation is continuously performed while the boom 7 is being raised, and the bucket 9 is slightly moved in the dumping direction. Therefore, when the second arm 22 is rotated clockwise in FIG. The 1st arm 21 is still engaged with the engaging portion 25, but the swinging member 28 is in a posture to bring the bucket control valve 35 to the neutral position, and this posture is held by the neutral position return spring 35b of the spool 35a. To be done.

In this way, as the boom 7 rises, the bucket 9 can perform a dumping operation and keep its opening 9a horizontal, so that the earth and sand will not spill to the tractor 2 side, and its attitude control is automatic. Moreover, since it is mechanically performed, no operation is required and reliability is increased.

The dumping lowering operation of the bucket 9 from the state where the boom 7 is in the raised posture is performed by pulling up the spool 35a with the operation lever 40, and at that time, the first arm 21 is also rotated, but in a direction away from the engaging portion 25. Turn to.

As described above, the raising operation of the boom 7 from the state in which the bucket 9 is in the substantially lifting posture is performed by the control valve 35 of the tilt cylinder 12.
A link mechanism R for holding the bucket 7 in a substantially lifting posture is provided to prevent soil spillage.

Further, in the present invention, the control box 41 is provided with a restraining member 52 for restraining the raising operation U, the lowering operation D and the dumping operation T of the operation lever 40 as shown in FIGS. 1 to 4.

In FIGS. 1 to 4, a hinge fitting 53 is fixed to the top plate of the control box 41 with bolts 54.
A shaft portion 55 of the check member 52 is attached to the boss portion 53A of the check member 52 so as to be slidable in the left-right direction and rotatable (raised). The check member 52 has a U-shaped plan view in which the inside of the vehicle body is open. It has a restraint portion 56 surrounded by parts. The check member 52 is made of a plate-like material, and has a slide stopper 57 that engages with the guide portion 42 on the lower surface thereof.

Therefore, when the check member 52 is operated, the hinge fitting 53
The restraining member 52 is erected with the boss portion 53A as a fulcrum and then slid in the left and right directions so that the restraint portion 56 is restrained by the operation lever 40 only in the squeeze direction S as shown in FIG.

As a result, while the loader is being lifted, the operation lever 40 is restrained in the lowering direction D and the dumping direction T by the restraining member 52 while the work is carried out under the loader to prevent the malfunction thereof. While improving safety by
Since the movement of the link mechanism R is also restrained, it is possible to prevent the link mechanism R and the like from being damaged. During the loader work, the restraint member 52 is automatically retracted and is in the unrestrained state.

Here, a restraint device having the configuration shown in FIGS. 8 and 9 is also conceivable.

In FIG. 8 and FIG. 9, 100 is a control box,
Long holes 101A, 102B that form a cross-shaped groove when overlapped with each other
The guide plates 101 and 102 having the above are slidably provided in the directions of the arrows. Each of the guide plates 101 and 102 has a lock hole 107 at a vertically corresponding position, and when the operation lever 103 is constrained, a pin 105 of a lock fitting 104 that is rotatable around a fulcrum 105 is inserted into the lock hole 107. I am trying to do it. Therefore,
In the restraint state of FIG. 9 in which the pin 105 is inserted into the lock hole 107, the operating lever 103 can be securely locked (checked), but the lock fitting 104 is unlocked (state of FIG. 8). When operating the operating lever 103 up / down / left / right,
The guide plates 101 and 102 also move, and the structure is complicated and the operating force becomes heavy.

(Effects of the Invention) The present invention is as described above, and according to the present invention, the raising operation of the boom from a state in which the work tool is in a substantially lifted posture is fed back to the control valve of the tilt cylinder, and the work tool can be substantially omitted. Since a link mechanism for holding the lifting posture is provided and the control box of the operation lever is provided with a check member for restraining the raising, lowering and dumping operations of the operating lever so as to be movable in the left and right directions and rotatable. The mechanical tool can automatically maintain the horizontal posture of the work implement and prevent spillage of earth and sand.

In addition, even if the operation lever is prevented from malfunctioning in order to ensure the horizontal posture by the above-mentioned link mechanism and to ensure the safety, the link mechanism or the like is not damaged.

[Brief description of drawings]

The drawings show an embodiment and a comparative example of the present invention. Fig. 1 is a perspective view of the main part of the present invention, Fig. 2 is the same plan view, Fig. 3 is the same elevation side sectional view, and Fig. 4 is the same elevation. Front (back) cross section,
FIG. 5 is a plan sectional view of the same, FIG. 6 is a side view showing the entire loader, FIG. 7 is a hydraulic circuit diagram, FIG. 8 is a perspective view of a comparative example, and FIG. 9 is a plan view thereof. 1 ... Boom type hydraulic working machine (loader), 7 ... Boom, 9 ...
Work tool, 11 ... Lifting cylinder, 12 ... Tilt cylinder, 34,3
5 ... Control valve, 40 ... Operating lever, 41 ... Control box, 52 ...
Checking member, R ... Link mechanism.

Continuation of the front page (56) References JP-A-64-48936 (JP, A) JP-A-59-435 (JP, A) Actually opened 62-128720 (JP, U) Actually opened 53-85002 (JP , U) Japanese Patent Publication No. 40-10890 (JP, B1) Japanese Patent Publication No. 52-14521 (JP, B1)

Claims (1)

[Scope of utility model registration request] 1. A boom (7) is movable up and down via a lift cylinder (11), and a work implement (9) attached to the boom (7) is tiltable via a tilt cylinder (12). The boom type hydraulic working machine (1) is provided with control valves (34) (35) for controlling the lifting cylinder (11) and the tilt cylinder (12) respectively, and the control valves (34) (3).
In a hydraulic operating device in which 5) can be operated independently and simultaneously by one operating lever (40), a tilt cylinder () is used to lift the boom (7) from a state where the work implement (9) is in a substantially lifting posture. A link mechanism (R) for feeding back to the control valve (35) of (12) to hold the work implement (9) in a substantially lifted posture is provided, and the control lever (40) has a control box (41) provided with a control lever (40). 40)
Boom-type hydraulic working machine characterized in that it is provided with a restraining member (52) for restraining the raising operation (U), lowering operation (D) and dumping operation (T) of the robot movably in the left-right direction and rotatable. Hydraulic operating device.