JP2568248Y2 - Arm control structure for small turning type power shovel - Google Patents

Description

[Detailed description of the invention]

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an arm control structure of a small turning type power shovel for excavation work.

[0002]

2. Description of the Related Art Conventionally, in a small turning type excavator in which an arm having a digging part is interlocked with a main link by a parallel link and a hydraulic actuator, the operation of the hydraulic actuator for offset is performed. There are those where the stop is repeated impulsively.

[0003]

However, in the above-mentioned conventional example, since the operation of the offset actuator is not performed smoothly, when the earth and sand loaded in the excavating bucket is loaded on a truck or the like, the same earth and sand is used. Was often shaken off and spilled.

[0004] For this reason, there is a type in which a rubber droop is provided at the base of the main boom to prevent the fall of the earth and sand. And rusting sometimes occurred.

[0005]

According to the present invention, an arm having a digging portion at the tip is connected to the tip of a main boom via an offset arm, and the arm is connected to an offset arm, a parallel link and a hydraulic actuator for offset. In a small turning power shovel that can be offset in a meandering manner, a low pressure having a high pressure relief circuit having a high pressure relief valve and a low pressure A relief circuit is provided in parallel with the low-pressure relief circuit, and an on-off valve is provided in conjunction with the pedal mechanism.By opening the on-off valve by operating the pedal mechanism, the low-pressure relief circuit Small turning type power characterized by being able to switch the oil path to the relief circuit Is to St. provide arm restricting structure in excavator.

[0006]

When a digging operation is performed by a small turning type power shovel, the offset arm and the digging portion are deviated with respect to the main boom by operating a hydraulic switching valve, but the offset operation is performed by pedaling a pedal mechanism. The oil passage is switched from the high-pressure relief circuit to the low-pressure relief circuit in conjunction with
The operation of the low-pressure relief valve operates slowly, so that the sediment loaded on the excavation part can be prevented from falling.

[0007]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described in detail with reference to the drawings. Reference numeral 1 denotes a small turning type power shovel, on which an engine 3 and an operation unit 4 are mounted on a turning frame 2.

[0008] Reference numeral 5 denotes a crawler-type traveling device. Reference numeral 6 denotes an excavator. An offset arm 8 and an arm 9 are connected to an upper portion of a main boom 7 of the excavator 6.

10 is a parallel link provided in parallel with the offset arm 8, 11 is a hydraulic actuator for offset, 12
Is an excavation bucket provided at the tip of the arm 9;
The excavating unit 13 is constituted by the excavating bucket 12 and the like.

In FIG. 2, reference numeral 9-1 denotes a mounting arm connected to the tip of the offset arm 8 via a vertical axis 14, and a bucket arm 9-2 is vertically moved at the tip of the mounting arm 9-1. They are freely connected.

The mounting arm 9-1 and the bucket arm
The arm 9 is constituted by 9-2.

The offset hydraulic actuator 11 is interposed between the right end 7-1 of the main boom 7 and the mounting seat 8-1 of the offset arm 8.

The parallel link 10 is interposed between the left end 7-2 of the main boom 7 and the mounting seat 9-3 of the mounting arm 9-1.

Reference numeral 15 denotes a hydraulic cylinder provided on the mounting arm 9-1, and reference numeral 16 denotes a hydraulic cylinder provided on the bucket arm 9-2.

In FIG. 3, reference numeral 20 denotes a hydraulic circuit for operating the offset hydraulic actuator 11;
Is a hydraulic pump, 22 is a main relief valve, and 23 is a hydraulic switching valve.

An oil passage 24 connects the hydraulic switching valve 23 to the left chamber 11-1 of the offset hydraulic actuator 11, and an oil passage 25 connects the hydraulic switching valve 23 to the right chamber 11-2 of the hydraulic actuator 11. It is.

In the middle of one oil passage 25, a branch pipe 26 is provided.
And a high pressure relief valve 27 and a low pressure relief valve 28 are provided. 26-1 is a high pressure relief circuit having a high pressure relief valve 27, and 26-2 is a low pressure relief circuit having a low pressure relief valve. Reference numeral 29 denotes an electromagnetic on-off valve provided on the side of the low-pressure relief valve 28, which is interlocked with the pedal mechanism 30.

Reference numeral 31 denotes a switch which is turned ON and OFF by a pedal mechanism 30. In the ON state, the opening / closing valve 29 is operated leftward to turn the low-pressure relief valve 28 ON. Reference numeral 32 denotes a power source, and reference numeral 33 denotes an operating rod provided on the offset hydraulic actuator 11.

The embodiment of the present invention is configured as described above. When excavation is performed by the small turning type excavator 1, the excavation is performed by linearly positioning the offset arm 8 with respect to the main boom 7. Although the work is performed, when excavating a place deviated rightward or leftward with respect to the machine body, the offset arm 8 is rotated.

First, when the excavating portion 13 is displaced to the right, the hydraulic switching valve 23 is operated to the right so that the high-pressure hydraulic oil from the hydraulic pump 21 is supplied to the offset hydraulic actuator 11.
To the left ventricle 11-1.

As a result, the hydraulic actuator for offset 11 contracts and pivots the offset arm 8 to the right to offset it in a center-folded manner.

Then, the excavating section 13 is in the state shown in FIG.

When the excavating portion 13 is deviated to the left with respect to the main boom 7 to perform earth loading and excavating work, the hydraulic switching valve 23 is operated to the left to operate the hydraulic pump 21 from the hydraulic pump 21 side. The hydraulic oil is guided to the right chamber 11-2 of the offset hydraulic actuator 11. As a result, the offset hydraulic actuator 11 is extended to rotate the offset arm 8 to the left. In this case, operate the pedal mechanism 30 to switch
When the switch 31 is turned on, the electromagnetic on-off valve 29 provided in the branch pipe 26 of the oil passage 25 is opened, and when the on-off valve 29 is opened, the low-pressure relief valve 28 is operated. Then, the mode is switched to the low-pressure relief circuit 26-2 in conjunction with the offset operation.

Therefore, since the offset hydraulic actuator 11 rotates slowly,
Sediment loaded in 12 does not spill.

Then, in this case, the excavating part 13
Then, loading operation and excavation operation can be performed.

When the low-pressure relief valve 28 is turned off and only the high-pressure relief valve 27 is used, the operation of the offset arm 8 is fast, and the soil can be shaken off.

As described above, according to the above embodiment, the arm 9 having the excavation portion 13 is connected to the main boom 7 via the offset arm 8, and the arm 9 is connected to the offset arm 8, the parallel link 10, In a small turning type power shovel in which the offset hydraulic actuator 11 can be offset in the form of a middle bend, a high pressure relief valve 27 having a high pressure relief valve 27 in the middle of an oil passage 25 connecting the offset hydraulic actuator 11 and the hydraulic switching valve 23. Relief circuit 26-1 and low voltage relief circuit 26-
2, a low-pressure relief circuit having a pressure relief circuit 2 is provided in parallel, and an on-off valve 29 is provided in the low-pressure relief circuit 26-2 in conjunction with the pedal mechanism 30, and the pedal mechanism 30 is operated by a pedal to open the on-off valve 29. In conjunction with the offset operation, the high-pressure relief circuit 26-1 to the low-pressure relief circuit 26
-2, the oil passage can be switched, and an on-off valve 29 that operates in conjunction with the offset operation is disposed on the low-pressure relief valve 28 side. When the offset arm is operated slowly, the falling of the earth and sand is prevented because the offset arm operates slowly.

In the prior art, a rubber drip or the like is provided at the base of the main boom. However, according to the present invention, the rubber drip or the like is not required at all and can be manufactured at a low cost.

Further, since it is not necessary to increase the strength of the support portion such as the offset arm, it is possible to make the whole compact.

FIG. 4 shows a mounting structure of a radiator and an oil cooler provided in a power working machine.
Reference numeral 50 denotes a radiator provided at the front of the engine 51, and reference numeral 52 denotes an oil cooler. Both sides of the radiator 50 and the oil cooler 52 are integrally supported by brackets 53 and 54. 55
Is an exhaust duct for cooling air formed between the radiator 50 and the oil cooler 52. A noise absorbing material is attached to the inner peripheral surface of the exhaust duct 55 to reduce noise.

Therefore, according to the above-described embodiment, since all the cooling air passing through the radiator 50 comes into contact with the oil cooler 52, the cooling efficiency of the oil cooler 52 is increased.

Further, by providing the exhaust duct 55, noise from the engine and the machine is absorbed and reduced.

The radiator 50 and the oil cooler 52
Since they are integrally mounted by the brackets 53 and 54, the number of parts is reduced, and the cost can be reduced.

[0034]

According to the present invention, a high-pressure relief circuit having a high-pressure relief valve and a low-pressure relief circuit having a low-pressure relief valve are arranged side by side in the oil passage connecting the offset hydraulic actuator and the hydraulic switching valve. ,
The low-pressure relief circuit is provided with an on-off valve linked to the pedal mechanism, and by operating the pedal mechanism to open the on-off valve, the oil path can be switched from the high-pressure relief circuit to the low-pressure relief circuit in conjunction with the offset operation. Therefore, when the earth and sand loaded on the excavation part are to be surely loaded on the truck without falling, the pedal mechanism is operated and the offset operation is performed, thereby operating the low-pressure relief valve. Thus, the offset arm can be operated slowly, and as a result, the falling of the earth and sand can be prevented. At this time, even when the offset operation is performed by manual operation, the pedal mechanism can be performed by stepping on the pedal, and the delicate opening and closing operation of the on-off valve can be reliably performed. In addition, when it is desired to speed up the operation of the offset arm and perform the work of shaking off the soil adhering to the excavated portion, the offset operation is performed without operating the pedal mechanism to operate the high-pressure relief valve. As a result, the offset arm can be operated quickly, and as a result, the soil attached to the excavated portion can be shaken off.

The present invention can be manufactured at low cost because no rubber dripping is required.

Moreover, since it is not necessary to increase the strength of the support portion of the offset arm, the structure can be made compact as a whole.

[Brief description of the drawings]

FIG. 1 is an overall side view of a small turning type power shovel equipped with the present invention.

FIG. 2 is a plan view of the same.

FIG. 3 is a hydraulic circuit diagram showing a main part of the present invention.

FIG. 4 is a perspective view showing another embodiment.

[Description of Signs] 7 Main boom 8 Offset arm 9 Arm 11 Hydraulic actuator for offset 23 Hydraulic switching valve 25 Oil passage 26-1 High pressure relief circuit 26-2 Low pressure relief circuit 27 High pressure relief valve 28 Relief valve for low pressure

Claims (1)

(57) [Scope of request for utility model registration] An arm (9) having a digging portion (13) at the tip is connected to the tip of a main boom (7) via an offset arm (8), and the arm (9) is connected to the offset arm (7). 8) and a parallel link (10) and a small turning power shovel that can be offset in a meandering manner by an offset hydraulic actuator (11), wherein the oil connecting the offset hydraulic actuator (11) and the hydraulic switching valve (23) is used. A high-pressure relief circuit (2) having a high-pressure relief valve (27) in the middle of the road (25).
6-1) and thereby juxtaposed low-pressure relief circuits (26-2) having a low-pressure relief valve (28), the low pressure Li
Linked with leaf mechanism (26-2) and pedal mechanism (30)
The on-off valve (29) is provided to connect the pedal mechanism (30).
Open by opening the open / close valve (29) by pedal operation
High pressure relief circuit (26-1) in conjunction with set operation
An oil passage that can be switched to a low-pressure relief circuit (26-2) .