JPS61273497A - Block clamping device - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to a block clamp device known as one of the attachments for a forklift.

(Prior Art) As shown in FIG. 3, this type of device is equipped with a pair of left and right clamp arms 5 extending in parallel in the front-rear direction and movably opened and closed on an arm holder 1.
By opening and closing the clamp cylinder 7 disposed on the base side, the block W is held and gripped from both sides. Further, many of the clamp arms 5 are formed to have a T-shaped cross section as shown in FIG. 4, and are disposed parallel to each other so as to face each other, and the contact surfaces against the block W are vertical surfaces.

(Problem to be Solved by the Invention) Generally, a block clamp device clamps several blocks at the same time. Deflection (including twisting) occurs due to the weight of W and vibrations during running, and this deflection, including twisting, occurs as a diagonally downward force that opens the clamp arm 5, as shown by the arrow in Fig. 5. . This is thought to be caused by the block W functioning as a wedge and pushing both arms apart to the left and right. As a result, there is a drawback that the clamping force of the block W is weakened and the block W is worn away, and this tendency becomes more noticeable on the distal end side.

In view of the above-mentioned problems, the present invention has as a technical problem to solve the problem of linking the bending or twisting that occurs in the clamp arm to an increase in clamping force.

(Means for Solving the Problem) The technical means for solving the above problem is a block clamp device that includes a pair of left and right clamp arms extending parallel to each other in the front-rear direction, which are movably opened and closed on an arm holder.
The clamping surface of the clamp arm, which has a rectangular cross section, against the block is slanted in a substantially figure-eight shape from the front so that it bites into the block due to the bending or twisting that occurs during clamping. be.

(Function) Therefore, when the clamp arm is clamping a block, if the clamp arm is deflected or twisted, this deflection or twist tends to displace the clamp surface of the clamp arm in the direction of biting into the block. That is, the bending or twisting that occurs in the clamp arm is used as a force to strengthen the clamping force.

(Example) Hereinafter, an example of the present invention will be specifically described based on the drawings. In the figure, 1 is an arm holder attached to the front of a lift bracket 3 that is raised and lowered along a mast 2 of a forklift.A pair of upper and lower guide bars 4 are attached in parallel to the front of the arm holder 1. A pair of left and right clamp arms 5 are attached to be movable in the left and right direction via arm brackets 6 formed at their bases. In addition, on the front side of the arm holder 1, a double piston-type (two double-acting cylinders are directly connected) clamp cylinder 7 is arranged in a floating manner parallel to the guide bars 4 between the upper and lower guide bars 4. At the same time, the rod of the clamp cylinder 7 is connected to the left and right clamp arms 5.
The clamp arm 5 is connected to an arm bracket 6, and the clamp arm 5 is opened and closed by the expansion and contraction of the clamp cylinder 7.

The left and right clamp arms 5 extend parallel to each other in the front-rear direction, have a rectangular cross section, and are arranged so that the long sides of the arms 5 extend in parallel to each other. That is, the left and right clamp arms 5 are arranged so that a straight line connecting the center O and the clamp surface A in the rectangular cross section is given a predetermined inclination angle θ with respect to the horizontal axis (clamping direction) passing through the center O. .

This embodiment is constructed as described above, and when several blocks W are clamped and lifted by the left and right clamp arms 5, the weight of the blocks W causes the clamp arms 5 to move as shown in FIG. rotational force in the direction of the X arrow,
In other words, twisting occurs as shown by the one-dot chain line. However, at this time, it is assumed that the contact surface between the block W and the clamp arm 5 does not slip due to frictional force.

Now, in FIG. 1, the inclination of the clamp arm 5 with respect to the clamp direction (horizontal axis direction) is θ,
If the torsion angle is Δθ, and the distance from the center O to the clamp surface A is r, the displacement of the clamp surface A of the clamp arm 5 due to the torsion will be in the direction of biting into the block W, and the displacement position S (biting amount) is 5-r(cos(θ-Δθ)-cosθ).

However, in this case, since the concrete block W is a rigid body, the above-mentioned torsional displacement (even though the apparent displacement is upward), so in reality, the clamping surface A of the clamp arm 5 relative to the block W is It does not move in the clamping direction, but acts as a force that pushes the center O of the clamp arm 5 in the anti-clamping direction.As a result, this force tends to displace the lamp arm 5 in the anti-clamping direction. acts on the block W as a clamping force.

In addition, although the clamp arm 5 is deflected due to the weight of the block W and the weight of the clamp arm 5, the direction of the deflection is changed from the conventional downward direction to the diagonally inward direction by adopting the above-mentioned inclined arrangement. 2 in Figure 1.
The direction is to bite into the block W as shown by the dotted chain line. Assuming that the horizontal inward deflection of the clamp arm 5 is t, this deflection (biting) includes biting due to twisting, and the actual deflection amount ΔS is Δ5−t−
Represented by S. In the conventional device, both clamp arms 5
In contrast, in this embodiment, both clamp arms 5 are arranged in an angular shape, thereby changing the direction of deflection to the diagonally inward direction. However, the deflection distance ΔS at this time appears to be an upward deflection, similar to the above-mentioned twisting, and substantially acts as a force pushing the clamp arm 5 in the anti-clamping direction. As a result, this force acts as a force to clamp the block W in the same manner as in the case of torsion.

FIG. 4 shows another embodiment of the invention. In this embodiment, the left and right clamp arms 5 have a T-shaped cross section, and are arranged at an angle of θ with respect to the horizontal axis. Although it is similar to the previous embodiment, in particular in this case, the distance r from the center O to the clamping surface in the T-shaped cross section of the clamp arm 5 is larger than in the case of the rectangular cross section described above, so that the clamping force is further increased.

Note that the cross-sectional shape of the clamp arm 5 is not limited to that shown in the drawings, and can be changed as appropriate as long as it is square.

(Effects of the Invention) As described in detail above, according to the present invention, the deflection or torsion that occurs when a block is clamped by a clamp arm can be utilized in a form that strengthens the clamping force. This prevents wear and tear and enables stable block handling operations. In addition, since the present invention does not include any special device to prevent wear-off, the structure itself remains as simple as before, and the effect in this respect is also large.
It is.

[Brief explanation of drawings]

The drawings show an embodiment of the present invention, and FIG. 1 is an explanatory diagram showing the main parts, FIG. 2 is a side view of the entire block clamp device, and FIG.
4 is an explanatory diagram showing another embodiment, and FIG. 5 is an explanatory diagram showing a conventional example. 1... Arm holder 4... Guide bar 5...
・Clamp arm 7... Clamp cylinder Applicant Toyota Automobile Co., Ltd. taI11 Agent Patent attorney Hidehiko Okada (2 others) No. 3 Fig. 5 Fig. 4

Claims (1)

[Claims] In a block clamp device that includes a pair of left and right clamp arms that extend parallel to each other in the front-rear direction and are movable to open and close on an arm holder, the clamp surface of the clamp arm, which is formed into a rectangular cross section, relative to the block may be damaged due to twisting or bending that occurs during clamping. A block clamp device that is arranged so that the front side is tilted in an approximately figure-eight shape so that it acts in a direction that bites into the block side.