RU2750620C1 - Installation for testing products for long-term durability - Google Patents

Abstract

FIELD: testing devices.

SUBSTANCE: invention relates to testing devices, namely systems for testing products with grippers for long-term strength. The system contains a bed, grippers, a test load meter, a loading mechanism associated with the first gripper, and a mechanism for maintaining a constant load with a drive. The test load meter is installed after the specified mechanism for maintaining a constant load through a U-shaped element, followed by a part on the same U-shaped element that simulates the end part of the element, which is subjected to clamping by a gripper installed in a replaceable protective pipe on the corresponding supports and which is affected by the loading mechanism.

EFFECT: provided is the ability to test products with grippers of various design.

3 cl, 2 dwg

Description

The invention relates to testing devices, namely to installations for testing products for long-term strength.

In the production of a number of products, the design documentation in accordance with GOST provides for their tests for long-term strength. For example, GOST 54867-2011 "Multilayer polymer pipes" refers to long-term hydrostatic strength as a value with the dimension of stress, characterizing the predicted average strength at temperature T and time t. For metals there is its own test method for long-term strength (GOST 10145-81, "Metals. Test method for long-term strength"). Samples for testing have different shapes and, accordingly, different designs of grips for performing their tests. Most often used are hinged (US Pat. RU # 2105965), threaded, collet (US Pat. RU # 112423) grippers. In some cases, tick-borne, jaw, eccentric and cam grips are used. Some of the grips listed require testing for reliability, holding capacity and long-term strength. The ultimate force required to pull out, for example, an anchor from concrete is called the holding capacity. The difference in holding capacity from long-term strength is only in the magnitude of the applied force, and the approach to performing such operations is practically the same. For example, in a device for determining the holding strength, the role of a fixed grip is played by a product pulled from the material surrounding it, and the rest of the structures are similar. Differences in known devices can only be found in methods and devices for applying forces. So, in various devices for removing parts with interference (pulleys, bearings and other similar products), mechanical and hydraulic mechanisms are used (website: https: //www.enerprom.ru/cat/39, found on the Internet on 11/21/2020). Moreover, for devices with which such tests are carried out, there are general technical requirements (GOST 28845-90). Among these requirements, one can single out the coaxiality of the application of the load to the sample and the automatic maintenance of the given load.

There is a known technical solution in the form of an installation for determining the bearing capacity of a tubular anchor, including a support frame equipped with length-adjustable supports, a loading device, a traction element with a helical surface installed with the ability to interact with the anchor and a loading device, a device for monitoring the generated force (US Pat. No. 2668953, G01N3 / 02, dated 01.08.2017). In this case, the connection of the traction element with the anchor is made through the spacers installed to interact with the inner surface of the tubular anchor. The installation is designed to apply a pulling force to the anchor or determine the holding capacity of the material using a screw or hydraulic type loading device. Although this rig is intended for testing an anchor, in principle it can be used to determine the long-term strength of such grips that work on "thrust". The disadvantage of the installation can be called the indirect determination of the force according to the readings of a pressure gauge or torque wrench and the inability to test other types of grippers.

Known installation for testing materials for long-term strength, containing a frame, two grips for the material, a loading mechanism associated with the first gripper, and a mechanism for maintaining a constant load, which includes a lead screw with a nut associated with the second grip and a drive for moving the screw connected to it. In this case, additional grips are coaxially installed between the first sample grip and the lever loading mechanism, with one additional grip connected to the lever loading mechanism, and the other additional grip is connected to the first sample grip by means of a screw with a nut. A traverse is located between the specified nut and the first grip of the specimen, and a dynamometer is installed between the additional grips, with the possibility of removing it without unloading the test specimen. The lever loading mechanism has a suspension with a load with the ability to move it along the lever (patent RU No. 2141636, G01N3 / 08 dated 01.21.1997, prototype).

This installation has a lever loading mechanism that acts on the movable gripper. In this case, the pulling rod can be skewed for gripping in the traverse guides and its effect on the dynamometer readings. It is intended for testing materials in the form of specimens of a certain shape, and is not intended for testing grippers.

The aim of the present invention is to improve the design and expand the technical capabilities of the installation by testing different types of grippers for long-term strength.

The technical result consists in creating a structure for testing for long-term strength for holding specimens of grips.

This goal is achieved by the fact that in a known installation for testing materials for long-term strength, containing a frame, grips, a test load meter, a loading mechanism associated with the first grip, and a mechanism for maintaining a constant load with a drive, in which the test load meter is installed after the specified mechanism maintaining a constant load through the U-shaped element, followed by a part on the same U-shaped element that simulates the end part of the element being clamped by a grip installed in a replaceable protective tube on appropriate supports and which is acted upon by a loading mechanism.

It is advisable to make the gripper loading mechanism in the form of a hydraulic cylinder with a manual or automated drive.

It is also possible to implement a mechanism for maintaining a constant load with a drive by moving a screw or a hydraulic cylinder.

To reduce the complexity of the testing process, it is advisable to use a microprocessor control system.

The presence in the claimed invention of features that distinguish it from the prototype makes it possible to consider it as corresponding to the "novelty" condition. The claimed device makes it possible to perform tests of various grippers, while the search did not reveal any analogs in the measuring technique, which means that it meets the criterion of “inventive step”.

The technical solution is illustrated by a drawing, which shows a general view of the installation for testing materials for long-term strength in the version with no automation. Figure 1 is a side view, and Figure 2 is an enlarged view of the grip being tested.

The installation (see Fig. 1) consists of a welded frame 1. On the one hand, there is a cradle in the frame, into which replaceable bushings 2 are installed and fixed, where the gripper under test is installed directly 3.On the other side of the device there is a rigid stop with installed it contains a loading element 4, which can be axially displaced and consists of a bolt with an eyelet 5 and nuts 6. A test load meter is attached to the eyebolt, for example, in the form of a dynamometer 7, having a coupling device 8 in the amount of 2 pieces on the sides. Head 9 is attached to the dynamometer using a coupling device, that is, a part that simulates the end part of a real part for a given grip of the product. Here, the circle A marks the part that is shown in FIG. 2 on an enlarged scale and showing the head 9 having a T-shaped boss 11, on which the grip 10 of the product under test is fixed. The T-boss 11 completely emits the special boss used on the real part being tested, such as an anchor for retention in concrete. For each test grip, the shape of this part is selected. The loading mechanism 12 acting on the gripper 10 can be made in the form of either a mechanical or a hydraulic drive.

The installation works as follows.

At the beginning of the test, the grip of the test product 3 is engaged with the head boss or other holding object 9, the bolt with the eyelet 5 is preloaded, corresponding to the holding force in the material. Then the gripper is loaded either by the product's own power screw with the gripper or by a loading mechanism built into the installation, for example, hydraulic up to a given loading value, which is recorded by the dynamometer reading.

Replaceable bushings 2, allow testing grippers with different dimensions and different values of the tested load. By wrapping them around the grips during the application of force, the safety of the test process can be increased. Note that it remains possible by simply changing part 9 to another holding grip for the test specimen, allowing it to be tested for tensile loads.

The gripper loading mechanism can also be implemented in the form of a hydraulic cylinder with a manual or automated drive. Also, the mechanism for maintaining a constant load can be made hydraulic. The use of digital force transducers in combination with controlled cylinder pressures will lead to programmable test execution.

The use of a force meter in series with the tested gripper in this design of the installation allows achieving the specified accuracy of loading the gripper. In place of the replaceable imitation part, other analogs for the grippers can be installed and tested. It is clear that the fastening of the replacement part of the simulator may be different from the above. Preloading allows different working conditions for the grippers to be simulated.

The machine is designed mechanically and tested on a number of available grippers. A variant with microprocessor control has been worked out.

This design allows testing on a single setup a fairly wide variety of grippers used in specialized devices.

Claims (3)

1. Installation for testing materials for long-term strength, containing a frame, grips, a test load meter, a loading mechanism associated with the first grip, and a mechanism for maintaining a constant load with a drive, characterized in that the test load meter is installed after the specified mechanism for maintaining a constant load through U-shaped element, followed on the same U-shaped element by a part simulating the end part of the element, which is clamped by a gripper installed in a removable protective tube on appropriate supports and which is acted upon by a loading mechanism. 2. Installation in accordance with claim 1, characterized in that the gripper loading mechanism is made in the form of a hydraulic cylinder with a manual or automated drive. 3. Installation in accordance with claim 1, characterized in that the mechanism for maintaining a constant load is made in the form of a hydraulic cylinder.

Images