RU2813091C1 - Impact test device - Google Patents

Abstract

FIELD: impact testing.

SUBSTANCE: invention relates to a test technique designed to determine wear or shape deformation in test objects subjected to impact loads, and in particular in impactors. The impact test device contains a power unit with a force-transmitting mechanism, a mechanism for cocking and lowering the impactor. In this case, the gear wheel of the transmission mechanism contains a number of grooves for pins that alternately act on the axis of the cocking mechanism, which can be rearranged in them to change the path travelled by the impactor before impact, and the tested impactors of different sizes are fixed in the corresponding blocks, fixed in the same way under the influence of the specified cocking mechanism, while the blow is performed with penetration to a given depth into the body of the control plate, which is moved in the groove of the device body to a different position after each blow, and the replaceable parts of the block have characteristics selected for the blow with penetration into the body of the control plate to a given depth.

EFFECT: expansion of the functionality of the stand by testing impactors of different sizes.

2 cl, 3 dwg

Description

The invention relates to a test technique designed to determine wear or shape deformation in test objects subjected to impact loads, and in particular in impactors.

Wear or shape deformation here refers to the displacement of a material from its original position on a solid surface under the action of another surface. Assessing the wear of a used object usually often involves measuring the surface topography of a sample before impact loading and of the same sample after loading. A typical design of one of the impact elements, which will be discussed below, is disclosed, for example, in a method for monitoring the performance of a galvanic impact mechanism (patent RU No. 2281452, F41A 19/59, dated July 10, 2002). The difference between the process of deformation of the strikers and the usual impact on the anvil is that the tip of the striker works to penetrate the material of the case primer body. Therefore, when testing such objects, it is important to comply with the impact conditions with penetration into a material with similar properties.

Impact loading techniques use different approaches. For example, during impact tests, the tested object can be accelerated with an impact on a stationary element (pat. No. 2104509, G01M 7/08, dated 08/10/1992) or be impacted by an impact element (pat. RU No. 2360225, G01M 17/06, G01N 3/34, dated 07/09/2007, Patent RU No. 2079831, G01N3/42, dated 06/17/1994, Patent RU No. 80953, G01N 3/30, dated 07/09/2007). In addition, the tested products can collide with each other (application RU No. 94037362, G01M7/00, dated 10/05/1994, patent RU No. 2759709, G01M7/00, G01N 3/34, dated 12/20/2020). The acceleration of the impactor in such tests is achieved, for example, by gravity, air pressure, electrical, electromagnetic drive, explosion or spring force. In addition, combinations of these agents can be used.

There is also a known method for assessing the deformability of a material during local extrusion, in which the measure of deformability is taken as the ratio of the plastic deformation of the thickness of the material at the top of the bulge, formed by the impact of a striker with a spherical end, to the impact speed (patent RU No. 2137107, G01N 3/28, dated 06.07 .1995). The technical solution develops a method for testing sheet material by pressing a spherical stamp into a sample clamped along the contour described in GOST 10510-80 "Metals. Method of testing for extrusion of sheets and tapes according to Eriksen" due to the use of impact instead of slow loading. The quality of metal according to GOST is assessed by the depth of the hole at which a through crack appears. The impact itself with a striker with a spherical end in the above method is performed in a powder or pneumatic installation, and the material under study serves as an anvil for the striker. That is, in the described solution, the deformability of the material is studied, and the possibility of deformation of the spherical striker is not assumed, especially if it is used repeatedly. Data on what size strikers the named installations can work with is not given in the description, due to the description of only the method. An essentially similar approach is implemented in a technical solution describing an impact meter using a submillimeter-sized impact ball to determine the dynamic hardness and response to impact of a magnetic disk (US Pat. No. 6050127, G01N3/30, dated 07/09/1999). The device allows the subsequent observation, for example, using a surface profilometer or high power microscope, of the characteristics of the dent made in the target material by a free falling impact ball, and the interpolation of the observed characteristics into analytical standards that, for a given ball size, weight and drop height, indicate dynamic hardness disc material at the test site.

Spring accelerators include, for example, a device for impact testing, designed to determine the stress-strain state of metal structures made of ferromagnetic steels and in which the acceleration of the indenter is performed by a spring-loaded striker (pat. RU No. 80953, G01N3/30, 07/09/2007). In this case, the indenter is made in the form of a cylinder made of non-magnetic material with a metal ball at the end, and the striker acts as a link transmitting the force of the spring. The dimensions of the striker are set by a spring, and the indenter is rigidly set by the diameter of the pipe. The proposed solution is not intended for testing the deformability of the spherical tip of the indenter. Another way for shock loading is described in the solution, where the impact is created by increasing the pressure inside the pipe (pat. RU No. 2685070, G01B 5/08, G01B 21/10, dated 09/28/2018). The change in diameter is measured with a fairly simple specialized device.

Another approach to performing impact tests is to hit the test object on an anvil (A.S. No. 815550, G01M 7/00, G01P 21/00, 04.04.1979, A.S. No. 991218, G01M 7/00, 07.29.1981 ). The impact of the product is carried out using free fall or a power exciter, thereby checking its impact resistance. The number of such blows is determined by the nature of the product being tested and, if it is some kind of device, then it is determined by the technical requirements. In this case, due to its hardness, the anvil cannot have a deformation hole and the tested object elastically bounces off it. To observe the deformation of an object, you need to perform a certain number of impacts. That is, such a design is not suitable for performing tests on the deformability of an object with penetration into a material of a certain hardness.

The closest solution would be a design containing a power element with a transmission mechanism, a mechanism for cocking and lowering the striking element onto the test object (patent RU No. 2360225, G01M 17/06, G01N 3/34, dated 07/09/2007). Here, a worm gearbox as part of the transmission mechanism ensures the transmission of torque from the power device sequentially to an elastic coupling and a flywheel with one roller, which ensures the load of the rocker with the impact element or striker when overcoming the compression force of the spring of the loading mechanism. Changing the frequency of impacts is achieved by increasing the number of rollers, and the amplitude of impacts by shifting the rollers along the radius. In this case, the rocker arm is mounted on an axis above the frame. Also, on the other side of the frame, a stop is installed on a protruding stand, to which a stand with the material being tested is attached. This makes the structure quite voluminous with increased material consumption. In addition, the blow can only be delivered to one point on the object. But the penetration of a striker to a given depth into a hardened object is not reported here. The design is not intended for such tests.

The objective of the invention is to improve the design of a device for impact testing and expand its technical capabilities for testing a number of standard sizes of impact elements.

The technical result that can be obtained using the proposed technical solution boils down to an improved design of the device, which allows testing a number of standard sizes of impact elements. The technical result achieved by the claimed invention consists in developing the design of a device for testing strikers of different sizes. The technical result is achieved by the fact that in the device for impact testing, containing a power unit with a force-transmitting mechanism and a mechanism for cocking and lowering the striker, changes are made in the gear wheel of the transmission mechanism in the form of a series of grooves for pins alternately acting on the axis of the cocking mechanism, which can they are rearranged to change the path traveled by the striker before the impact, and the tested strikers of different sizes are fixed in the corresponding blocks, fixed in the same way under the action of the specified cocking mechanism, while the strike is performed with penetration to a given depth into the body of the control plate, moved in the groove of the device body in a different position after each impact, and the replacement parts of the block have characteristics selected for impact with penetration into the body of the control plate to a given depth. It is advisable to supplement the device with a means of mechanically moving the control plate after an impact to a position for the next impact.

In addition, the device is additionally equipped with a set of replaceable parts for securing the tested elements of different standard sizes in the same housing of the replaceable block.

The proposed technical solution is illustrated by drawings, where in Fig. 1 is a front view of the proposed impact test apparatus; FIG. 2 shows a side view. Figure 3 shows a sectional view of a block containing the test object. As can be seen, here in FIG. 1 marked welded body 1, gears 3, 4, 5, 8, 13, power drive 6, shafts 2, 7, guide rack 9, cocking axis 10 with a lever having surface A, body of the holder of the test striker (impact element) 11 , (the designation for the striker is shown in Fig. 3) key 12. Along the diameter there are six grooves with surface profile B for the pins shown in the following figure. The grooves are necessary to change the radius of rotation of the specified pins and, accordingly, the height of the striker.

In fig. 2 are also indicated, on the housing 1, power drive 6, shafts 2 and 7, key 12. In addition, a control plate 14, pins (six pieces) 15 on wheel 13, bolts 16 for fastening the housing 11, shafts 17, 18 and 19 are shown, and a spring 20 for pressing the control plate 14 against the groove surface support. Here, the gear wheel 13 with its pins 15 acts on parts of the mechanism for cocking and lowering the striker, consisting of a cocking striker 21 and a bushing that imitates the body of the striker 22. The specified groove for the control plate 14 is highlighted by an external arrow B in the guide rail 9 and makes it possible to manually or mechanically moving the plate by an appropriate means after each impact.

In fig. Figure 3 shows a replaceable block located in the housing 11, which contains: a key 12, a control plate 14, a striker cocking 21, a bushing simulating the striker body 22, a welded body of the device 1, a threaded plug 23, a washer 24, a power spring 25, an insert 26, test striker 27. The upper position of the bushing simulating the striker 22 is designated as position G, the lower position of the same bushing as D. And the symbol H means the estimated lifting height of the striker or the path traversed by the striker. Surface E serves as a mounting location for the replacement unit. In the figures shown, the force transmitting mechanism includes shafts and gears. The cocking and lowering mechanism is determined by the cocking axis, pins, a bushing simulating the firing pin body, and a power spring.

The device for testing the impact of the impact element (striker) operates in the following sequence.

The test striker 27 is installed in a replaceable unit (Fig. 3), which has a liner 26, a bushing simulating the striker body 22, a power spring 25, a plug 23, a washer 24, a key 12 and a housing 11 into which these parts are assembled. This assembled unit is then installed on surface E at the estimated height H in the fixture and secured with bolts 16 (Fig. 2). When installing this unit on the body of the testing device, the bushing simulating the body of the striker 22 has the ability to move vertically when the power unit 6 is driven into rotation (Fig. 2). When the power unit 6 rotates, the rotation system of all gears 3, 4, 5, 8, 13 on the shaft system 2, 7, 17, 18, 19 is started due to the transmission of torque from gear 3 to gear 13 with pins 15, which sequentially, come into contact with the surface A of the cocking axis 10 (Fig. 1), as a result of which the shaft 19 rotates and the striker cocking axis 21 rotates (Fig. 3). When rising, the hammer cocking nose engages with the hammer bushing 22 and begins to lift the bushing 22 with the insert 26 installed in it, as a result of which the spring 25 is compressed. At the moment the pin 15 leaves surface A, the hammer bushing sharply returns to its initial position, thereby lowering the liner 26 and all associated elements, and accordingly, the end part of the firing pin 27 hits the control plate 14, which is installed in the guide rail 9. In this case, the cocking axis 10 rotates and the surface A of the cocking axis lever 10 approaches the next pin 15 to perform the subsequent cycle of cocking and lowering the firing pin.

After performing a specified number of impacts, the test object undergoes visual or instrumental control, for example, on a profile measuring device. In the absence of deviations exceeding the specified ones, the tested object is considered to have passed the test.

The impact test fixture cocks and lowers the firing pin into the test plate 14 in ten different locations as the plate moves after each impact. The lifting and impact of the test striker into the control plate occurs in approximately 1 revolution of the power unit 6.

To control the impact resistance of the firing pin, spring 25 has a force higher than the force of the standard working spring by a given amount. Placing the striker 22 ensures that the striker 27 is raised by a size of 15...17 mm. The impact of the test striker 27 occurs with sufficient force to leave a mark on the control plate 14 with a depth of 0.4...0.45 mm. Washer 24 (Fig. 3) is used to additionally adjust the force created by spring 25.

When testing impact elements of a different standard size, parts in housing 11 are replaced with parts of the structure corresponding to the impactor size being tested. The parts for each standard size result in a set of replacement parts that provide the required depth penetration into the control plate. In this case, the power spring can also be changed if necessary if it does not provide the calculated penetration. If the dimensions of the firing pin being tested do not allow the use of appropriate replacement parts, then a replacement block for this firing pin is manufactured separately along with the required parts. Thus, after performing the impact test and checking for changes in the profile, a conclusion is given about the compliance of the test object with the technical specifications.

In principle, the proposed solution allows the use of a device for impact testing for cyclic deformability of the test object.

Design documentation has been developed for the developed structure and test tests are being carried out.

Claims (2)

1. A device for impact testing, containing a power unit with a force-transmitting mechanism, a mechanism for cocking and lowering the striker, characterized in that the gear wheel of the transmission mechanism has a number of slots for pins that alternately act on the axis of the cocking mechanism, which can be rearranged in them for changes in the path traveled by the striker before the impact, and the tested strikers of different sizes are fixed in the corresponding blocks, fixed in the same way under the action of the specified cocking mechanism, while the strike is performed with penetration to a given depth into the body of the control plate, which is moved in the groove of the device body to another position after each impact, and the replacement parts of the block have characteristics selected for impact with penetration into the body of the control plate to a given depth. 2. The device according to claim 1, characterized in that it is additionally equipped with a set of replaceable parts for securing the tested elements of different sizes in the same body of the replaceable block.