JPS586577B2 - Grip device for gripper feed - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a gripping device for use in a gripper feed.

Gritpuff feed is commonly used in presses to feed the material.

Gripping devices used here include moving grippers and fixed grippers, but it goes without saying that in either case, a gripping device that reliably grips the material with a small operating force is required.

By the way, as an example of a conventional gripping device, there is one that is configured to apply a pressing force to a material by applying an arcuate motion to a gripper block with the material feeding direction as a tangential direction.

However, according to this, when gripping, a pressing force acts in a direction oblique to the feeding direction of the material, so a horizontal component of force along the feeding direction is generated, which causes slippage between the gripper block and the material. This may cause the grip position to shift.

Another example of a gripping device is one that grips the material by giving a gripper block an arcuate motion with the tangential direction perpendicular to the material feeding direction; this grips the material using a simple pressing force. It attempts to grip using only the frictional force.

However, when the material is transported, a large force due to back tension acts on the material in the opposite direction to the transport direction, so it is difficult to maintain this grip with only frictional force, and slips are likely to occur.

In order to prevent this, it is possible to increase the operating force and apply a large pressing force, but in that case, when releasing the material (opening the gripper), a large force corresponding to the operating force must be applied. This results in a disadvantage that it lacks not only durability but also high speed.

The object of the present invention is to propose a gripping device that grips materials accurately and reliably, and has durability and high speed.

Embodiments of the present invention will be described below with reference to the drawings.

The figure shows a configuration example in which the present invention is applied to a moving gripper, in which a slider S that slides on a guide shaft G is provided, and this slider S is equipped with a gripper device.

The gripper device is constructed as follows.

That is, one end of the link 2, which is swingably supported by the pin 1 in a fixed position, is pivoted to one end of the other link 4 by the pin 3 so as to form a dogleg shape.

The link 2 is integral with the lever 2A, thereby forming a bell crank.

The link 4 is used as a grip block and has a hard friction pawl 5 at its tip.

A link 8 is swingably supported by a pin 6 in a fixed position.
The tip of the link 4 is pivotally connected to the link 4 by a pin 9.

It is desirable that the pin 9 be located as close to the friction pawl 5 as possible.

As described above, a chain is formed by the virtual link 10 connecting links 2, 4, 8 and pins 1, 6.

11 is a compression spring whose elasticity is used as the operating force of the grip block.

12 is an extrusion pin for release, 13 is a stopper, 14 is a block on the fixed side located at the same fixed position as pins 1 and 6, 1
5 is the material.

FIG. 2 is a diagram showing the principle of the configuration of FIG. 1, and as is clear from this diagram, the circular curve e of the friction pawl 5 is
It is considered that the distance of f from the central pin 3 becomes gradually longer from e to f.

Now, to explain the operation with reference to FIG. 2, when a force P acts as an operating force on the tip A of the lever 2A (this force is given by the compression spring 11), the link 2 moves counterclockwise around the pin 1. As a result, while the link 4 is restrained by the rotation trajectory of the link 8, that is, the movement trajectory of the pin 9, a rotation force is exerted to rotate the link 4 in a clockwise direction around the pin 9. As a result, the friction pawl 5 and the block 14 pinch the material 15.

The clamping force generated by this clamping pressure becomes a gripping force that grips the material 15.

If the link 8 were to be parallel to the material 15, the force acting on the pin 9 would only be perpendicular to the material 15.

At this time, no component force in the direction parallel to the material 15 is generated, so no slip occurs between the friction pawl 5 and the material 15.

Also, if the links 8 are not parallel, the force acting on the pin 9 is
A certain angle (temporarily assume this is θ) with respect to the perpendicular to the material 15.

) acts in the direction of inclination.

At this time, a component force is generated in a direction parallel to the material 15, which causes slip.

However, since this slip is determined by the coefficient of friction between the friction pawl 5 and the material 15 and the size of the angle θ, it is possible to prevent slip by setting the angle θ in advance so that no slip occurs. You will be able to do it.

Next, the pressing force of the material 15 by the friction pawl 5 will be considered.

The operating force P and the vertical distance from pin 1 to link 4 are a and b, respectively, and the force acting in the direction of link 4 is Q1 pin 9.
Let α be the angle between the vertical line passing through and the link 4.

Considering the moment about pin 1 P・a:Q・b Must.

Also, the pressing force W to be determined is W=QCOSα It is.

Therefore, both formulas are used.

Here, the smaller b and the smaller the angle α, the larger the pressing force W becomes. However, as explained above, the force P causes the link 2 to rotate counterclockwise around the pin 1. , as the link 4 rotates clockwise about the pin 9, the angle α becomes smaller.

Therefore, a very large pressing force W is generated with a small operating force P.

The fact that the operating force P can be reduced in this way means that
This means that the pushing force of the lever 2A by the push-out pin 12 when releasing the material 15 is also small, which is extremely advantageous in terms of durability and high speed.

When the present invention is used as a moving gripper as in the illustrated embodiment, when the material 15 is conveyed while being gripped, a large force due to back tension acts in the opposite direction to the conveying direction.

However, this generates a frictional force X on the contact surface between the material 15 and the grip surface, and this frictional force acts in the direction of reducing the angle α, so the pressing force of the friction pawl 5 against the material 15 increases, and as a result, It is convenient that the movement due to back tension is suppressed.

Note that during transportation or when transportation is stopped, an inertia force that overcomes the back tension acts, and the resulting frictional force Y acts in the direction of increasing the angle α, but as described above, the pressing force W If you set it large enough,
The grip is maintained sufficiently by the frictional force on the grip surface at that time.

As detailed above, according to the present invention, it is possible to accurately grip a material by pressing the friction pawl against the material with a force substantially perpendicular to the material, and also to generate a large pressing force with a small actuation force. Because it is possible to
Even if the actuating force is pressed with a substantially perpendicular force as described above, there is no need to make the actuation force particularly large, and this produces the effect of sufficiently exhibiting durability and high speed.

It goes without saying that this invention can also be applied to fixed grippers.

[Brief explanation of drawings]

FIG. 1 is a front view showing an embodiment of the present invention, and FIG. 2 is an explanatory diagram of the operation. 1... Fixed pin, 2... Link, 3... Pin, 4... Link, 5... Friction pawl, 6... Fixed pin, 8... Link, 9... Pin, 14... Fixed block.

Claims (1)

[Claims] 1. The link 2 and the link 4, which is a movable block, are pivotally connected to the pin 3 in a dogleg shape, and the end of the link 2 is pivotally connected to the fixed pin 1, and the link 2 forms a bell crank. A spring 11 for rotating the link 2 is provided at the tip of the crank, and a circular curve is provided at the tip of the link 4 so that the distance from the pin 3 is at one end so as to face the fixed block 14. A friction pawl 5 is installed which gradually becomes longer as it goes from one end to the other end, and a link 8 pivotally connected to a fixing pin 6 is attached to the link 4.
A gripping device for a gripper feed, which is connected by a pin 9 to a position close to the installation position of the friction pawl 5.