JPH09255298A - Clamping device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To surely synchronize adjacent split arms with each other during non-application of loads until external forces are applied to the split arms in a clamping device having divided split arms. SOLUTION: Left and right split arms 5L and 5R are attached to clamp holders 4 via attaching shafts 7L and 7R so as to be rotated, and these are individually rotated by clamp cylinders. The attaching shafts 7L and 7R are rotated integrally with the split arms 5L and 5R, a friction pad 24 is provided between the opposing shaft end surfaces of the attaching shafts 7L and 7R, and during non-application of loads until external forces are applied to the split arms 5L and 5R, the opening/closing operations of the left and right split arms 5L and 5R are synchronized by the friction force of the friction pad 24.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a clamp device known as one of attachments for forklift trucks, and relates to loading and unloading work of roll-shaped articles (hereinafter referred to as roll paper) such as newsprint paper and kraft paper, and particularly, different diameter The present invention relates to a clamp device suitable for gripping work.

[0002]

2. Description of the Related Art A conventional roll clamp device for handling roll paper is generally provided with a swing type long arm and a fixed type short arm, and a work for simultaneously grasping stacked roll papers having different diameters. In order to accommodate the above, the swing type long arm is divided into two in the left-right direction (width direction), and the divided arm, that is, the split arm, can be individually opened and closed by a clamp cylinder. An example of such a split type roll clamp device is, for example, Japanese Utility Model Laid-Open No. 57-711
No. 98 publication.

By the way, in the case of the above-mentioned split type roll clamp device, during the loading operation of roll papers of different diameters, the split arm rotated in the closing direction contacts the roll paper of large diameter and one of the splits. It is convenient for carrying out cargo handling work that the split arms rotate synchronously until the arms reach the stroke end in the opening direction, that is, when no load is applied to the split arms. Therefore, conventionally, a diversion valve is provided in the hydraulic circuit of the clamp cylinder, and the flow amount of the hydraulic oil sent to the clamp cylinder is controlled by the diversion valve to synchronize the opening and closing operations of both split arms.

[0004]

However, in the clamp device of the type in which the split arms are synchronized by using the above-described conventional flow dividing valve, the hydraulic oil fed to the clamp cylinder is particularly affected by the performance of the flow dividing valve. When the number is small, poor synchronization may occur. That is, the clamp cylinders of the split arm, which have small turning resistance, are activated first because the turning resistances when opening and closing the arms are different between the left and right split arms. There is a problem that the work becomes difficult.
Then, the problem of poor synchronization of the split arm occurs regardless of the presence or absence of the flow dividing valve, and also occurs even if the drive means for rotating the split arm is a hydraulic motor.

The present invention has been made in view of the above problems, and an object of the present invention is to eliminate a synchronization failure of a split arm in a clamp device having a split split arm. .

[0006]

Means for Solving the Problems In order to solve the above problems, the present invention is configured as follows. That is, according to the invention of claim 1, in a clamp device including a plurality of split arms divided in the width direction, interlocking means for interlocking the split arms with each other when there is no load and releasing the interlock when there is a load. It is equipped with. Here, when the load is applied, when the arms for loading and unloading work are opened and closed, the split arm moved to the closing side comes into contact with the load to be grasped, or the split arm moved to the open side reaches the stroke end. An external force is applied, and no load means a state where no external force is applied.

Therefore, the invention as set forth in claim 1 is constructed as described above.
According to the invention, the plurality of divided split arms are interlocked via the interlocking means when no external force is applied and the interlocking is released when the external force is applied. That is, the split arm works together unless it receives external force by coming into contact with luggage or reaching the stroke end, and the synchronization failure is eliminated.

According to a second aspect of the present invention, in the clamp device according to the first aspect, the interlocking means comprises a friction member interposed between the facing surfaces of the split arm. Therefore, according to the invention of claim 2, the split arm is interlocked by the frictional force of the friction member when there is no load, and the interlocking is released when the friction member slides when loaded. The interlocking means composed of a friction member has a simple structure and can be easily applied to an existing clamp device.

According to a third aspect of the present invention, in the clamp device according to the first aspect, the interlocking means is interposed between the facing surfaces of the split arm and is engaged when there is no load, and the engagement is performed when there is a load. It is characterized in that it is composed of a concave member and a convex member to be released. Therefore, according to the invention of claim 3, the split arm is interlocked by the engagement of the concave member and the convex member when there is no load, and the interlocking of the split arm is released by the detachment of the concave member and the convex member when loaded. Further, in the case of the interlocking means composed of the concave member and the convex member, compared with the friction member, it is possible to enhance structural durability and maintain its performance for a long period of time.

[0010]

BEST MODE FOR CARRYING OUT THE INVENTION Embodiments of the present invention will be specifically described below with reference to the drawings. The present embodiment is intended for a roll clamp device suitable for loading and unloading roll paper, and as shown in FIG. 3, a clamp holder 4 is provided on the front surface of a lift bracket 2 that moves up and down along a mast 1 of a forklift. Is rotatably mounted via a rotating device 3 about a horizontal axis. The clamp holder 4 is provided with a pair of openable and closable clamp arms consisting of a long arm 5 and a short arm 6 that face each other, and clamp pads 5a and 6a are attached to the tips of the arms 5 and 6, respectively.

As shown in FIG. 4, the long arm 5 is composed of two split arms 5L and 5R in the width direction (left and right direction), and the split left and right split arms 5L and 5R have their base portions. Is the clamp holder 4
Is rotatably pivotally mounted via concentric mounting shafts 7L and 7R, and each is individually rotated by clamp cylinders 8L and 8R as drive means.
The bases of the clamp cylinders 8L and 8R are rotatably attached to the tip of the clamp holder 4 by a pin 9.
The tip of the piston rod is the split arm 5L, 5
It is pivotally attached to R by a pin 10.

Further, as shown in FIG. 1, the mounting shafts 7L and 7R of the split arms 5L and 5R are fixed in the circumferential direction and the axial direction by a retaining pin 11 which is radially inserted from the outer circumference of the base of the split arms 5L and 5R. The clamp holder 4 is fixed in both directions, and is rotatable with respect to the clamp holder 4 via a metal 12 that receives a radial force and a metal 13 that receives an axial force. As a result, the split arms 5L and 5R are axially positioned with respect to the clamp holder 4.

FIG. 5 shows a hydraulic circuit for driving the clamp cylinders 8L and 8R. As shown, the hydraulic pump 1
The hydraulic oil discharged from 4 is the oil control valve 1
5 is sent to the left and right clamp cylinders 8L and 8R via the rotary valve 16, and the rotary valve 16 is communicated at a rotation interval of 90 degrees. In the rotary valve 16, the flow rate (or return oil) sent to the left and right clamp cylinders 8L, 8R is controlled to control the clamp cylinders 5L, 5R.
A shunt valve 17 is provided to synchronize the operation of the.
In the figure, 18 is a pilot type check valve, and 19 is a tank.

On the other hand, as shown in FIG. 3, the short arm 6 has its base side rotatably attached to the clamp holder 4 by a shaft 20, and its base end side.
A cylinder 2 for position adjustment in which a rod 21 is pivotally attached to the short arm 6 and a rod end is pivotally attached to the short arm 6 by a pin 22.
It is adapted to be rotated by 3. It should be noted that the short arm 6 is rotated for position adjustment when the diameters of roll paper to be handled are greatly different, and is used in a fixed state during normal cargo handling work.

In the roll clamp device as described above, interlocking means is provided between the left and right split arms 5L and 5R to interlock the opening and closing of the unloaded split arms 5L and 5R. As shown in FIG. 1, the interlocking means according to the present embodiment is constituted by a friction pad 24 made of a material capable of obtaining a high friction force such as a rubber pad or a brake pad as a friction member. Numeral 24 is interposed on the opposing end surfaces of the mounting shafts 7L and 7R which rotate integrally with the split arms 5L and 5R.

The friction pad 24 is formed in the shape of a disc or a donut, and is fixed to one mounting shaft (the left mounting shaft 7L is shown in the drawing) by a screw 25, as shown in FIG. The friction pad 24 is the split arm 5
When assembling L and 5R, that is, when inserting the mounting shaft 7L into the shaft holes of the split arm 5L and the clamp holder 4,
The shaft end surface of the other mounting shaft 7R is pressurized with a predetermined pressure.
It is held by a stop pin 11 for fixing to L and 5R. The friction pad 24 may be attached by an adhesive, or a square convex portion may be formed on one end surface or both end surfaces of the friction pad 24 and fitted into a square concave portion provided on the end surfaces of the mounting shafts 7L, 7R. It may be in the form of being crowded.

Next, the work of loading roll paper of different diameters by the roll clamp device constructed as described above will be explained. As illustrated in FIG. 6, when the small-diameter roll paper W2 is stacked vertically on the large-diameter roll paper W1 with a part of the outer periphery aligned, first, both roll papers W1,
The clamp pad 6a of the short arm 6 is abutted against the outer circumference of W2. Next, when the oil control valve 15 is operated to the closing side, the hydraulic oil discharged from the hydraulic pump 14 is sent to the bottom chambers of the left and right clamp cylinders 8L and 8R via the rotary valve 16 and the flow dividing valve 17, and the left and right split arms 5L and 5R are rotated to the closing side with the mounting shafts 7L and 7R as pivots.

At this time, the left and right split arms 5L,
If the rotation resistance of 5R is different, depending on the performance of the flow dividing valve 17, the hydraulic oil is mainly the clamp cylinder 8L on the side where the resistance is small.
Or, it will flow into the 8R and cause a poor synchronization of the split arms 5L and 5R. However, according to the present embodiment, the friction pad 24, which is interposed between the left and right mounting shafts 7L and 7R in a pressurized state, uses the frictional force to both shafts 7L and 7R.
Link 7R. Therefore, both split arms 5L,
The 5Rs rotate in synchronization even if their rotation resistances are different.

When the clamp pad 5a of one split arm 5L comes into contact with the large-diameter roll paper W1 and an external force (load) is applied to the split arm 5L, after that, the friction pad 24 and the mounting shaft 7R slide. , The other split arm 5R is further rotated, and its clamp pad 5a is brought into contact with the small diameter roll paper W2. Thus, the different-diameter roll paper is gripped as shown in FIG.

The gripping action is released by operating the oil control valve 15 to the open side. At this time, the left and right split arms 5L and 5R are attached to the friction pad 2.
By the action of 4, it is rotated in synchronization with the opening side while maintaining the relative displacement at the time of gripping. Then, when one split arm 5L reaches the stroke end first and is stopped, the friction pad 24 slips as in the case of gripping, and only the other split arm 5R is rotated to the stroke end.

As described above, according to the present embodiment, both split arms 5L and 5R can be reliably rotated in synchronization with each other when no load is applied until the external force is applied to the left and right split arms 5L and 5R. . That is, since the poor synchronization of the split arms 5L and 5R is eliminated, the troublesomeness in the cargo handling work due to the poor synchronization is eliminated, and the cargo handling work is efficiently performed.

Further, in the present embodiment, the friction pad 24 system is used as the interlocking means of both split arms 5L, 5R, so that a simple structure is sufficient and the mounting shafts 7L,
Since it can be assembled using a small space between 7Rs, it can be easily applied to existing devices. Although the above description is for the case of gripping different diameters, when handling roll paper of the same diameter or long length, both split arms 5 are used.
L and 5R are always opened and closed in synchronization with each other.

FIG. 7 shows the second embodiment. In the second embodiment, concave portions 7a and convex portions 7b, which are fitted with an annular gap left in the radial direction, are set on the opposing end faces of the mounting shafts 7L and 7R, and the friction pad 24 is added to the gap. It is interposed in a pressed state, and is otherwise configured in the same manner as in the first embodiment. Therefore, the second embodiment
In this case as well, it is possible to obtain the same effect as that of the first embodiment described above.

Next, a third embodiment shown in FIG. 8 will be described. In the third embodiment, the friction pad 24 is mounted on the mounting shaft 7L via the position adjusting means, and the other parts are configured similarly to the first embodiment. That is, the friction pad 24 is adhered to the head of the pad holder 24a, and the screw portion 24b of the pad holder 24a is attached to the screw hole of the attachment shaft 5L so as to be axially positionally adjustable.
The head of the pad holder 24a is formed in a square shape. Therefore, according to the third embodiment, the frictional force (pressure) of the friction pad 24 can be easily adjusted by rotating the pad holder 24a with a tool such as a spanner during assembly or wear.

Next, a fourth embodiment will be described with reference to FIGS. 9 and 10. In the fourth embodiment, the interlocking means of the split arms 5L and 5R is composed of a convex / concave member which can be engaged / disengaged. That is, the mounting shafts 7L, 7R
On the same circumferential line of the opposing end faces of the above, balls 27 as convex members are provided on one side and circular recesses 28 as concave members are provided on the other side at the same intervals.

The ball 27 is constantly pressed into the circular recess 28 by a spring 30 as a pressing member housed in a vertical hole 29 having an appropriate length in the axial direction. The configuration excluding the interlocking means configured as described above is the same as in the first embodiment.
Is the same as

Therefore, according to the fourth embodiment, when no external force is applied to both split arms 5L and 5R, the ball 27 is kept engaged with the circular recess 28 and the two mounting shafts 7L. , 7R are interlocked, so that both split arms 5L, 5R rotate in synchronization. When one of the split arms 5L and 5R comes into contact with the roll paper or reaches the stroke end and an external force is applied, the ball 27 escapes from the circular recess 28 against the pressing force of the spring 30. The interlocking of the split arms 5L and 5R is released.

In the case of the interlocking means using the ball 27 and the circular concave portion 28, the wear resistance can be improved as compared with the case of utilizing the above-mentioned frictional force, and therefore, the initial resistance can be maintained for a long period of time. A highly durable interlocking device that can maintain performance can be provided.

FIG. 11 shows the fifth embodiment. The fifth embodiment is another example of the case where the interlocking means is composed of a convex member and a concave member, and the engaging portions of the concavities and convexities are formed in a tooth profile (waveform). That is, one mounting shaft 7
A sliding shaft 33 having a tooth-shaped uneven portion 32 on the shaft end surface is slidably fitted in the small-diameter shaft portion 31 formed at the end portion of the L in the axial direction, and the uneven portion 32 is attached to the other mounting shaft 7R. It is engaged with a tooth-shaped uneven portion 34 formed on the shaft end surface of the shaft, and is pressed by a pressing disc spring or a compression coil spring 35 interposed between the small-diameter shaft portion 31 and the sliding shaft 33. The interlocking means having such a configuration can also achieve the intended purpose of eliminating the poor synchronization of the split arms 5L and 5R.

The present invention is not limited to the illustrated embodiments, but may be modified as appropriate without departing from the spirit of the invention. In the illustrated embodiment, since the mounting shafts 5L and 5R are connected by the interlocking device, there is an advantage that the mounting space is small. However, instead of this, the split arms 5L and 5R are connected by the interlocking device. You may do it. In that case, it is desirable to construct the interlocking means consisting of a friction member or the interlocking means consisting of a convex member and a concave member by utilizing the space between the facing side surfaces near the center of rotation.
Further, the invention is not limited to the rotary type roll clamp device, but may be applied to a sliding (parallel movement type) clamp device or a clamp device in which both opposing clamp arms are movable.
Furthermore, the drive means of the split arms 5L, 5R is not limited to the hydraulic cylinder, but may be changed to a hydraulic motor.

[0031]

As described in detail above, according to the present invention,
In the clamp device with split split arm, because the split arm synchronization failure can be eliminated,
It becomes possible to efficiently carry out cargo handling work.

[Brief description of drawings]

FIG. 1 is a plan view showing a split arm attachment portion and an interlocking device according to a first embodiment of the present invention.

FIG. 2 is a detailed view of part A of FIG.

FIG. 3 is an overall side view of a roll clamp device.

FIG. 4 is a perspective view showing a split arm.

FIG. 5 is a hydraulic circuit diagram for driving a clamp cylinder.

FIG. 6 is an explanatory diagram showing a work mode of gripping a different diameter.

FIG. 7 is a cross-sectional view showing a second embodiment.

FIG. 8 is a cross-sectional view showing a third embodiment.

FIG. 9 is a cross-sectional view showing a fourth embodiment.

FIG. 10 is a sectional view taken along line BB of FIG. 9;

FIG. 11 is a partially cutaway plan view showing a fifth embodiment.

[Explanation of symbols]

 4 ... Clamp holder 5 ... Long arm 5L, 5R ... Split arm 7L, 7R ... Mounting shaft 8L, 8R ... Clamp cylinder 24 ... Friction pad 27 ... Ball 28 ... Circular recess

Claims (3)

[Claims] 1. A clamp device having a plurality of split arms divided in the width direction, wherein the split arms are interlocked with each other when no load is applied,
Clamping device equipped with interlocking means to release the interlocking under load. 2. The clamp device according to claim 1, wherein
The clamping device, wherein the interlocking means is a friction member interposed between the facing surfaces of the split arm. 3. The clamp device according to claim 1, wherein
A clamping device comprising: a concave member and a convex member, wherein the interlocking device is interposed between the opposing surfaces of the split arm and is engaged when there is no load, and is disengaged when there is no load.