JP3385379B2 - Grab bucket - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a grab bucket which is mainly suspended from a crane and used for loading and unloading bulk materials.

[0002]

2. Description of the Related Art Conventionally, a single rope type grab bucket operated by a crane or the like has been used for transferring loose materials such as wood chips, powdered ore and earth and sand.

As a conventional single rope type grab bucket of this type, for example, one having a structure shown in FIGS. 7 and 8 is known. This grab bucket comprises a pair of shells 2 and 2 that constitute a grab 1 and are opened and closed so as to face each other, and a lower frame 3 in which the pivot centers of the shells 2 and 2 are pivotally supported by shafts 2a and 2a. , An upper frame 5 located above the lower frame 3 and connected to the back surface of each shell 2, 2 via suspension arms 4, 4, ..., and between the upper and lower frames, a hydraulic cylinder 6 for the lower frame 3. The intermediate movable frame 7 connected through the intermediate movable frame 7, the lower end of which is fixed to the intermediate movable frame 7, and the suspension which is extended upward by being wound around pulleys provided in the intermediate movable frame 7 and the upper frame 5, respectively. A wire rope 8 for lowering and closing the grab, and a hydraulic cylinder control means for controlling the operation of the hydraulic cylinder 6 by opening and closing an oil passage communicating with the hydraulic cylinder 6. Equipped and are configured.

When the glove 1 is opened, the hydraulic cylinder control means is operated to set the hydraulic cylinder 6 in a free state so that the lower frame 3 is moved from the intermediate movable frame 7 by the weight of the shell and the lower frame 3. When the shell 2 is detached and lowered, the back surface of the shell 2 is suspended by the suspension arm 4, the position of the rotation center shaft 3a is lowered, and the glove is opened.

In the closing direction of the grab 1, the intermediate movable frame 7 is lowered by feeding the wire rope 8 downward from the open state while the hydraulic cylinder 6 is kept in the free state. Three
, The hydraulic cylinder 6 is made inextensible in this state, and the wire rope 8 is pulled up, whereby the intermediate movable frame 7 is pulled up so as to approach the upper frame 5, whereby both shells 2 and 2 close each other. It is designed to be operated in the direction.

[0006]

However, in the conventional single rope type grab bucket as described above, when handling substances that easily adhere to the grab such as powdery ores and clayey earth and sand having high adhesiveness, After releasing the grab and releasing the contents after grasping the object, the opening operation of the grab does not easily separate it, and the next grasping operation must be performed while it is attached to the inner surface of the shell. There was a problem of reduced efficiency.

In view of the state of the art as described above, the present invention is capable of reliably releasing the contents held at the time of opening the grab even when handling a substance that easily adheres to the inner surface of the shell. The purpose is to provide.

[0008]

The features of the present invention for solving the above-mentioned conventional problems and achieving the intended purpose are as follows.
A pair of shells that form a grab and are opened and closed to face each other, a lower frame that pivotally supports the center of rotation of the shell, and a rear surface of each shell and a suspension arm that are located above the lower frame. And an intermediate movable frame that is between the upper and lower frames and that is connected to the lower frame via a hydraulic cylinder, and has a lower end fixed to the intermediate movable frame and the intermediate movable frame. The operation of the hydraulic cylinder by closing the wire rope for closing the hanging grab, which is wound around the pulleys provided in the frame and the upper frame and extended upward, and the oil flow path communicating with the hydraulic cylinder. A grab bucket comprising a hydraulic cylinder control means for controlling the above. A bypass passage which connects the said hydraulic cylinder barrel with a predetermined interval from the parts, in that so as to accelerate the piston moving between the upper portion and the body portion of the hydraulic cylinder.

It is preferable to interpose a control valve for adjusting the oil flow rate in the bypass passage. When the glove is opened, it is preferable that the inner bottom surface of the shell inclines upward and the inner surface of the shell is made of stainless steel. It is preferable that

[0010]

BEST MODE FOR CARRYING OUT THE INVENTION Next, an embodiment of a grab bucket according to the present invention will be described with reference to FIGS. The same parts as those in the above-mentioned conventional example are designated by the same reference numerals for description.

In the figure, 1 is a grab, 3 is a lower frame, 4 is a suspension arm, 5 is an upper frame, 6 is a hydraulic cylinder, 7 is an intermediate movable frame, and 8 is a wire rope.

This grab bucket comprises a pair of shells 2 and 2 that constitute the glove 1 and are opened and closed facing each other, and the center of rotation of each shell 2 and 2 is a shaft 3a, as in the above-mentioned conventional example. The lower frame 3 pivotally supported by 3a, the upper frame 5 located above the lower frame 3 and connected to the back surfaces of the shells 2 and 2 via the suspension arms 4, 4 ,. And an intermediate movable frame 7 connected to the lower frame 3 via a hydraulic cylinder 6, and a pulley having a lower end fixed to the intermediate movable frame 7 and provided on the intermediate movable frame 7 and the upper frame 5, respectively. The wire rope 8 for suspending and closing the grab, which is wound around the cable and extended upward, and the movement of the hydraulic cylinder 6 by opening and closing the oil flow path communicating with the hydraulic cylinder 6. It is constituted by a hydraulic cylinder controlling means for controlling.

The grab 1 has a shaft 3 with respect to the lower frame 3.
a and 3a are respectively rotatably supported by shells 2 and 2, and in the closed state where the openings are joined to each other, the bottom is closed and a gripping space 9 in which a loose item is stored is formed. To be formed.

The inner surface of the shell 2 is made of stainless steel, and its shape is such that when the glove 1 is fully opened, the inner bottom surface 10 of the shell 2 inclines upward toward the inside of the shell with respect to the ground. ing.

The lower end of the suspension arm 4 is pivotally supported by the back of each shell 2, and the upper end of the suspension arm 4 is pivotally supported by the upper frame 5. Are connected in a suspended state with respect to.

An oil tank 11 and a radio signal receiver 12 are attached to the lower frame 3. In the figure, reference numeral 13 is a fuel filler port provided on the upper portion of the oil tank 11, and 14 is a receiving antenna of the wireless signal receiver.

The radio signal receiver 12, when receiving a signal from the radio signal transmitter, transmits an opening command to the hydraulic circuit for controlling the hydraulic cylinder 6.

The intermediate movable frame 7 has a hollow portion 15 inside.
The sheave cases 16 and 16 are fixedly provided on the lower right side of the front surface and the lower left side of the rear surface, and sheaves 17 and 17 are rotatably provided in the sheave cases 16 and 16.

The hydraulic cylinder 6 has a cylinder portion 6a.
And a piston 6b reciprocally housed in the cylinder portion 6a, and a piston rod 6 connected to the piston 6b and protruding from the upper end of the cylinder portion 6a so that it can freely move in and out.
and c.

The lower end of the cylinder portion 6a is connected to the lower frame 3, and the tip end portion of the piston rod 6b is connected to the top portion of the intermediate movable frame 7 by screwing or the like.
As a result, the lower frame 3 and the intermediate movable frame 7 are connected via the hydraulic cylinder 6.

The flow path 1 communicating with the upper and lower sides of the piston 6b
8 is formed, and a check valve 19 for restricting the inflow of oil from the upper side to the lower side of the piston 6b is provided in the flow path 18 thereof.

A rod-shaped piston rod 6c is provided on the piston 6b so as to project upward.

As shown in FIG. 6, the hydraulic circuit for controlling the operation of the hydraulic cylinder 6 has one end of the conduit 20 connected to the upper end of the cylinder portion 6a of the hydraulic cylinder 6, and a throttle valve 21 and a pilot check valve 22. After that, the cylinder part 6
The other end of the conduit 20 is connected to the lower end of a. Further, the lower end of the cylinder portion 6 a is communicated with the oil tank 11 via the connecting conduit 23.

The throttle valve 21 is interposed between the upper end of the cylinder portion 6a and the pilot check valve 22, and the glove 1
When releasing the cylinder part 6a from the top
a The opening speed of the glove 1 is changed by adjusting the flow rate of the oil flowing to the lower end portion.

The pilot check valve 22 is a solenoid valve 24.
When the pilot check valve 22 is closed, the oil above the piston 6b in the cylinder portion 6a is dammed to stop the hydraulic cylinder 6 from descending, and the pilot check valve 2 is opened.
When 2 is opened, oil can flow into the hydraulic cylinder 6 below the piston 6b through the conduit 20 and the hydraulic cylinder 6 becomes free.

The hydraulic cylinder 6 has a piston 6
A bypass passage 25 for accelerating b is provided, and the bypass passage 25 uses a bypass conduit 26 to communicate the upper end portion of the cylinder portion 6a with a portion at a predetermined distance from the upper end portion. It is formed by.

Further, the bypass conduit 26 is provided with a throttle valve 2
The oil flow rate can be adjusted by interposing 7.

The upper frame 5 is formed in such a shape that the upper portion of the intermediate movable frame 7 is fitted in the central portion of the upper frame 5, and is provided with rotatable pulleys 28, 28 at its front and rear portions.

The intermediate movable frame 7 is hung relative to the upper frame 5 by operating the wire rope 8. That is, as shown in FIG. 4, the lower end of the wire rope 8 is fixed to both sides of the intermediate movable frame 7, and the wire rope 8 is fixed to the upper frame 5.
The pulleys 17 and 17 are respectively wound around the pulleys 28 and 28 and extended upward, and the upper ends thereof are fixed to suspenders 29 for suspending them on a crane or the like.

Next, the opening / closing operation of the grab 1 of the grab bucket and the operation of the hydraulic cylinder 6 will be described.

In the initial state of the grab bucket, the grab 1 is placed with the upper, lower and intermediate movable frames in close proximity to each other.
Is closed and suspended from a crane.

At this time, the pilot check valve 22 of the hydraulic circuit is closed, there is no oil flow in the hydraulic cylinder 6, and the hydraulic cylinder 6 is in a locked state.

When opening the glove 1, first, the wireless signal receiver 12 is caused to receive a signal for opening the grab so that an operating current flows through the solenoid valve (solenoid valve) 24, and the solenoid valve is operated only during the energization. 24 is operated to the pilot check valve opening side.

When the solenoid valve 24 operates, the pilot check valve 22 opens, and the cylinder portion 6a passes through the conduit 20.
The oil flows from the upper part to the lower part of the cylinder, and the hydraulic cylinder 6 becomes free.

As a result, the lower frame 3 is attached to the shell 2,
2 and the lower frame 3 are separated from the intermediate movable frame 7 by the weight of the lower frame 3 and are lowered, and in the state where the back portion of the shell 2 is suspended by the suspension arm 4, the position of the rotation center shaft 3a is lowered and the glove 1 is opened. ing.

At this time, the hydraulic cylinder 6 is extended,
The piston 6b rises relative to the cylinder portion 6a, and when the piston 6b reaches the position where the bypass conduit 26 of the cylinder portion 6a is connected, that is, the position of the piston 6b shown by the chain line in FIG. The bypass passage 25 is opened, and the amount of oil flowing from above the piston 6b to below is increased, and the extension speed of the hydraulic cylinder 6 is increased. As a result, the opening speed from the open position indicated by the phantom line (dashed line) in FIG. 3 to the fully open position indicated by the solid line is accelerated.

As described above, since the extension speed of the hydraulic cylinder 6 is increased and the opening speed of the grab 1 is accelerated,
When the loose material is stored inside, the loose material stuck inside the shell 2 is shaken off by the action of inertia. The acceleration of the opening speed is adjusted by the opening / closing degree of the throttle valve 27.

Next, the glove 1 is landed on the object in the open state.

In the closing direction of the glove 1, the intermediate movable frame 7 is lowered by lowering the intermediate movable frame 7 by letting out the wire rope 8 while the hydraulic cylinder 6 is in the free state from the landing state. The hydraulic cylinder 6 is made inextensible in this state by approaching the frame 3, and then the wire rope 8 is pulled up to pull up the lower frame 7 so as to approach the upper frame 5, whereby the rotation center shafts 3a, 3a. Is moved up so that the two shells 2 and 2 are operated so as to close each other.

At this time, in the hydraulic cylinder 6, the pilot check valve 22 is closed, the flow of oil from the upper side to the lower side in the cylinder portion 6a is stopped, and the movement in the extension direction is restricted. On the other hand, the flow of oil from the lower side to the upper side is the flow path 1 provided in the piston 6b.
8 through which the hydraulic cylinder 6 contracts while maintaining a cushioning effect.

The throttle valve 28 interposed in the bypass passage 25 is adjusted in consideration of the adhesiveness of the loose material, and normally the throttle valve 27 is closed to close the bypass passage 25 and the hydraulic cylinder 6 is normally closed. It may be used as it is.

In the above-described embodiment, the example in which the solenoid valve is opened and closed by the wireless operating device is shown, but a wired type may be used.

[0043]

EFFECTS OF THE INVENTION A pair of shells that constitute a glove and are opened and closed to face each other, a lower frame that pivotally supports the rotation center of the shell, and a lower frame that is located above the lower frame. An upper frame connected to the back surface via a suspension arm, an intermediate movable frame between the upper and lower frames and connected to the lower frame via a hydraulic cylinder, and a lower end fixed to the intermediate movable frame. A wire rope for closing the hanging grab, which is wound around pulleys respectively provided on the intermediate movable frame and the upper frame and extended upward.
In a grab bucket comprising a hydraulic cylinder control means for controlling the operation of the hydraulic cylinder by closing the oil flow path communicating with the hydraulic cylinder,
A bypass passage is provided to communicate between the upper end of the hydraulic cylinder and the hydraulic cylinder body that is spaced from the upper end by a predetermined distance, and accelerates a piston that moves between the upper end and the body of the hydraulic cylinder. By doing so, when the glove is fully opened by changing the opening speed of the grab, the object inside the grab will be separated due to the vibration, and any loose object can be appropriately handled. You can

Further, by interposing a control valve for adjusting the oil flow rate in the bypass passage, the change in the opening speed can be adjusted, and the load can be released while maintaining the normal cushioning property up to the middle. The impact at the time of release can be adjusted according to the ease of use, and the unnecessary impact at the time of glove release can be suppressed by closing the control valve in the case of easy removal.

Further, when the glove is opened, the bottom surface of the shell is inclined inward and upward, so that the loose object to be worked is easily separated from the shell.

Further, since the inner surface of the shell is made of stainless steel, the loose object to be worked is easily separated from the shell.

[Brief description of drawings]

FIG. 1 is a front view showing an example of an embodiment of a grab bucket according to the present invention.

FIG. 2 is a side view of the above.

FIG. 3 is a front view showing the above-mentioned glove open state.

FIG. 4 is a perspective view showing a winding state of a pulley and a wire rope.

5 is a longitudinal sectional view showing the hydraulic cylinder in FIG. 1. FIG.

FIG. 6 is a schematic view showing a hydraulic circuit of the above.

FIG. 7 is a front view showing a conventional grab bucket.

FIG. 8 is a side view of the above.

[Explanation of symbols]

1 grab 2 shell 3 Lower frame 4 hanging arms 5 Upper frame 6 hydraulic cylinder 6a Cylinder part 6b piston 6c piston rod 7 Intermediate movable frame 8 wire rope 9 Grasping space 10 Inner bottom 11 oil tank 12 Radio signal receiver 13 Filling port 14 antenna 15 Hollow part 16 sheave cases 17 Pulley 18 channels 19 Check valve 20 conduits 21 Throttle valve 22 Pilot check valve 23 Connection conduit 24 Solenoid valve 25 Bypass 26 Bypass conduit 27 Throttle valve 28 Pulley 29 Hanging equipment

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Claims (4)

(57) [Claims] 1. A pair of shells that constitute a grab and are opened and closed so as to face each other, a lower frame that pivotally supports the center of rotation of the shell, and a lower frame that is located above the lower frame. An upper frame connected to the back surface via a suspension arm, an intermediate movable frame between the upper and lower frames and connected to the lower frame via a hydraulic cylinder, and a lower end fixed to the intermediate movable frame. And a wire rope for closing the hanging grab extended upward by being wound around pulleys respectively provided in the intermediate movable frame and the upper frame, and closing the oil flow path communicating with the hydraulic cylinder. And a hydraulic cylinder control means for controlling the operation of the hydraulic cylinder by the glove bucket. A bypass path is provided for communicating between the upper end and the body of the hydraulic cylinder at a predetermined distance from the upper end so as to accelerate the piston moving between the upper end and the body of the hydraulic cylinder. A glove bucket that is characterized by what you have done. 2. The glove bucket according to claim 1, wherein a control valve for adjusting an oil flow rate is interposed in the bypass passage. 3. The glove bucket according to claim 1, wherein the bottom surface of the shell inclines inward and upward when the grab is opened. 4. The glove bucket according to claim 1, 2 or 3, wherein the inner surface of the shell is made of stainless steel.