JPH0515077Y2 - - Google Patents

Description

[Detailed description of the invention] [Field of industrial application] The present invention relates to a material testing machine that grips a test piece and applies a load to the test piece using a pair of gripping mechanisms on a fixed side and a movable side. The present invention relates to a device for preventing descent of a gripping mechanism in a materials testing machine, which prevents the gripping mechanism from lowering when replacing the gripping teeth of the movable gripping mechanism.

[Prior art and its problems]

A material testing machine that applies a tensile load or the like to a test piece generally has a pair of gripping mechanisms that grip the test piece, spaced apart in the vertical direction, and the upper gripping mechanism is fixedly arranged. The lower gripping mechanism is attached to the piston rod of the hydraulic actuator so as to be movable up and down with the piston rod.

By the way, the above-mentioned gripping mechanism is designed to grip the test piece with a pair of gripping teeth that are arranged so as to approach and separate from each other, and the gripping teeth are those that match the shape and dimensions of the test piece. Otherwise, the test piece cannot be firmly gripped. Therefore, when the shape or dimensions of the test piece changes, the gripping teeth must be replaced, but in automatic material testing machines where the test piece is replaced by a robot, the gripping teeth are also replaced by the robot. Ta. In order to maintain good test efficiency, the robot replaces the test piece and gripping teeth when the piston rod of the hydraulic actuator, to which the lower movable side gripping mechanism is attached, is in the raised position and the fixed side gripping mechanism is attached to the piston rod. In connection with this, the test specimens were exchanged at a location where they could be exchanged.

However, when replacing the gripping teeth of the movable gripping mechanism supported by the piston rod in the raised position, the robot hand must grip the gripping teeth located inside the gripping mechanism. If a power outage occurs during a power outage, the hydraulic pressure in the hydraulic actuator will drop due to the power outage, and the gripping mechanism will descend to the lowest position along with the piston rod, but the robot hand facing inside this gripping mechanism will also fall into the gripping mechanism. Since the robot hand would be lowered by the robot hand, there was a risk of breakage of the robot hand.

[Purpose of invention]

The present invention overcomes the problems with the conventional ones described above, and prevents the gripping mechanism from descending even if a power outage occurs when replacing the gripping teeth of the movable gripping mechanism.
An object of the present invention is to provide a device for preventing a gripping mechanism from falling in a material testing machine, which prevents a robot from breaking when applied to an automatic material testing machine.

[Summary of the idea]

The present invention provides a materials testing machine equipped with a gripping mechanism that grips a test piece with movable gripping teeth that are arranged so as to be able to rise and fall, and that come into contact with the gripping mechanism to prevent the gripping mechanism from descending below a predetermined height. and a driving means for moving the stopper between a position in which it abuts the gripping mechanism and a position in which it does not abut, and the driving means moves the stopper to a position in which it abuts the gripping mechanism when replacing the gripping teeth. The gripping mechanism is designed to prevent the gripping mechanism from lowering below a predetermined height even in the event of a power outage accident.

[Example of idea]

The present invention will be explained below with reference to embodiments shown in the drawings.

FIG. 1 shows the main part of the lower part of a material testing machine equipped with a device for preventing descent of a gripping mechanism according to the present invention. A piston rod 4 is connected to a piston (not shown) that is raised and lowered by supplying hydraulic pressure into the cylinder 3.
passes through an opening 5 formed in the testing machine table 1 and reaches above the testing machine table 1.

A gripping mechanism 6 is attached to the upper end of the piston rod 4. This gripping mechanism 6 has a frame 7 supported on the upper end of the piston rod 4.
A pair of hydraulic cylinders 8A and 8B are formed within the frame 7 and are opposed to each other with a distance in the horizontal direction. Inside both hydraulic cylinders 8A, 8B are hydraulic cylinders 8A, 8B.
Piston rods 9A and 9B are disposed which are moved in the horizontal direction by the supply of hydraulic pressure therein, and the tips of these piston rods 9A and 9B are opposed to each other in a groove 10 formed in the center of the frame 7. are doing. Furthermore, both piston rods 9A,
Gripping teeth 11A and 11B are removably attached to the tip of the piston rod 9B to grip a test piece (not shown) by moving the piston rods 9A and 9B in the approaching direction. A gripping mechanism having the same configuration as this gripping mechanism 6 is fixedly attached to the upper frame of a material testing machine (not shown) so as to be located directly above the gripping mechanism 6, and the gripping mechanism on the fixed side and the movable side After gripping a test piece (not shown) with the gripping mechanism 6, the hydraulic actuator 2 moves the piston rod 4 to pull it onto the test piece.
Compression or cyclic loads can be applied.

On the testing machine table 1, there are a pair of parallel guide rails 12A, 12A, 12B, 1 on each side of the piston rod 4 of the hydraulic actuator 2.
2B is attached, and these guide rails 12A, 12A or guide rails 12B, 1
The square columnar stoppers 13A and 13B are guided by the frame 7 of the gripping mechanism 6.
It is arranged on the testing machine table 1 so as to move between a widthwise intermediate position immediately below the test machine and a position away from directly below. The heights of the stoppers 13A and 13B are so formed that they have a small gap from the bottom surface of the gripping mechanism 6 at the predetermined replacement position. In addition, each stopper 13A, 13B has a piston rod 16A, which is supported by a bracket 14A, 14B protruding from the tester table 1, as shown in FIG.
16B are connected, and by supplying air to these air cylinders 15A, 15B, the stoppers 13A, 13B move toward the guide rails 12A, 1.
2B. Note that in this embodiment, both air cylinders 15
A, 15B are located directly below the gripping mechanism 6, so that the stroke of the piston rod 4 of the hydraulic actuator 2 is controlled by the gripping mechanism 6 as compared to the air cylinders 15A, 15B.
The range is such that it does not come into contact with 15B.

Next, the operation of the embodiment described above will be explained.

In an automatic material testing machine, since the specimen and the gripping teeth 11A, 11B are replaced by a robot, the gripping mechanism 6 is moved to a predetermined replacement position by raising and lowering the piston rod 4 of the hydraulic actuator 2 prior to replacing the gripping teeth 11A, 11B. will be moved up to After that, the stopper 13A, 1 in the retracted position
3B is moved to a position directly below the gripping mechanism 6 by driving the air cylinders 15A and 15B, and is opposed to the bottom surface of the gripping mechanism 6 from below with a small gap therebetween.

In such a state, the gripping teeth 11A, 11B of the gripping mechanism 6 are replaced by a robot.
In the unlikely event that a power outage occurs when replacing B, the hydraulic pressure in the hydraulic actuator 2 decreases, and even if the gripping mechanism 6 attempts to descend together with the piston rod 4 due to its own weight, if the gripping mechanism 6 descends a small distance, both stoppers will be attached to the gripping mechanism 6. 13A and 13B abut against each other from below to prevent the gripping mechanism 6 from further lowering. Therefore, even if the robot hand faces inside the gripping mechanism 6, the gripping mechanism 6 will descend a very small distance and stop immediately, so there is no risk of the robot hand breaking.

Note that after replacing each gripping tooth 11A, 11B of the gripping mechanism 6, the air cylinders 15A, 15B
The material test may be performed again after supplying air to the stopper 13A, 13B and moving each stopper 13A, 13B to a retracted position where they do not interfere with the lowering of the gripping mechanism 6.

According to this embodiment, the gripping teeth 11 of the gripping mechanism 6
Even if a power outage occurs when replacing parts A and 11B, the gripping mechanism 6 will only be slightly lowered and both stoppers 13 will be removed.
Since it is supported by A and 13B and stopped, there is no fear that the robot hand will break even if the gripping teeth 11A and 11B of the gripping mechanism 6 are replaced by the robot.

It should be noted that the present invention can be applied not only to automatic material testing machines but also to material testing machines in which test pieces and gripping teeth 11A, 11B are manually tested, so that replacement work can be performed safely.

[Effect of idea]

As explained above, according to the present invention, even if a power outage occurs when replacing the gripping teeth of the movable side gripping mechanism, the lowering of the gripping mechanism can be prevented, which improves safety when replacing the gripping teeth manually. becomes higher,
Furthermore, when applied to an automatic material testing machine, breakage of the robot hand can be prevented.

[Brief explanation of the drawing]

FIG. 1 is a partially longitudinal sectional front view showing an embodiment of a device for preventing descent of a gripping mechanism in a material testing machine according to the present invention, and FIG. 2 is an enlarged side view of FIG. 1. 1... Test machine table, 2... Hydraulic actuator, 3... Cylinder, 4... Piston rod,
6...Gripping mechanism, 8A, 8B...Hydraulic cylinder,
11A, 11B...Gripping teeth, 13A, 13B...
Stopper, 15A, 15B...Air cylinder.

Claims (1)

[Claims for Utility Model Registration] 1. In a materials testing machine equipped with a gripping mechanism that grips a test piece with movable gripping teeth that are arranged to be able to rise and fall, the gripping mechanism is in contact with the gripping mechanism and is below a predetermined height of the gripping mechanism. A gripping mechanism in a material testing machine characterized by comprising: at least one stopper for preventing the stopper from descending to Anti-descent device. 2. A device for preventing descent of a gripping mechanism in a material testing machine according to claim 1, wherein a plurality of the stoppers are arranged at symmetrical positions on the gripping mechanism.