SU853456A2 - Braking device for test-bed for impact testing - Google Patents

Description

(54) BRAKE DEVICE FOR STAND FOR IMPACT TESTS

one

The invention relates to the test. namely, to brake devices for shock testing of products, in particular electronic products.

Impact brake testing devices are known which consist of a set of elastomer gaskets 1.

However, such a design brake devices significantly limits their performance. These devices have a “soft power characteristic and provide for obtaining the laws of inhibition with long durations at small amplitudes of shock pulses.

With an increase in amplitude and a decrease in the duration of shock acceleration, the elastomer gaskets are destroyed, since the magnitude of their deformation is not limited and may exceed the elastic limit.

The closest technical solution to the invention is a braking device to an impact test bench, made in the form of alternating masses moving in the direction of impact, and dampers 2.

The stand of the bench is braked by increasing its mass by successively attaching to it the masses of the braking device and compressing the dampers located between the masses. The law of inhibition is ensured by selecting the magnitude of each of the masses and parameters of the dampers.

However, at high table speeds (several tens of m / s), when receiving large amplitudes of the shock pulse, the law of deceleration will be mainly determined by the amount of deformation of the dampers, which may exceed the elastic limit. This will lead to a sharp deterioration in the accuracy of the reproduced pulse and the destruction of the dampers. On this braking device, one can obtain only a “soft power characteristic at small amplitudes of the shock pulse.

The purpose of the invention is to improve the accuracy of reproduction of a given pulse shape and to expand the possibilities of controlling the pulse shape.

Claims (2)

This is achieved by the fact that the masses are made with axial protrusions and counter grooves and are equipped with interchangeable restrictive elements installed in the grooves, the stiffness of which is greater than the stiffness of the dampers, but less than the stiffness of the masses, and there is an axial gap between the restricting element of each mass and the protrusion the maximum amount of compression of the damper placed between these masses. The drawing schematically shows the proposed brake device. The device contains placed in guides 1 moving alternating masses 2 and dampers 3. Alternating masses 2 are made with axial protrusions 4 and notches 5. There are restrictive elements 6 in recesses 5, between them and projections 4 there is an axial gap 7. On the braking device There is a table 8 stand with the test product 9. The stiffness of the restrictive elements 6 is greater than the stiffness of the dampers 3, but less than the stiffness of the masses 2. The gap 7 must be less than the maximum amount of compression of the damper 3, placed between the respective masses 2. The brake device operates as follows. The first mass 2 of the device in the direction indicated by the arrow hits the table 8 with the product under test 9. By successively connecting the masses 2 to the mass of the moving table 8, the dampers 3 are sequentially compressed until the axial projections 4 come into contact with restrictive elements 6. When contacting the projections 4 with restrictive elements 6, further compression of the dampers 3 is minimized, as restrictive elements 6 begin to deform, the rigidity of which is greater than the rigidity of the dampers 3 and less the stiffness of the masses 2. As a result, the kinematic energy of the table 8 is completely transformed into the energy of deformation of the dampers 3 and elements 6. By varying the rigidity of the dampers 3 and elements 6, it is possible to obtain various laws of table braking, i.e. various forms of shock pulses. Damper material is usually rubber or elastomer. Restrictive elements 6 and mass 2 can be made from both metal and non-metal. Compared with the known braking devices, using the proposed braking device, you can get higher levels of y, gravy overloads with different durations of action, and the dampers work within the elastic deformation, which improves the shape of the shock pulse, and also prevents them from destruction due to with the presence of restrictive elements. In addition, the restrictive element provides a smooth transition from the "soft power characteristic of dampers to" hard power characteristic of alternating masses, the rigidity of which many times exceeds the rigidity of the dampers. Such a smooth transition further improves the shape of the shock pulse when playing high-intensity shock overloads. The greater the number of colliding masses with intermediate elements contained in the braking device, the greater the energy of the moving table with the test article can be extinguished. Varying the number and stiffness of dampers, restrictive elements, impacting masses, as well as the various forms of interchangeable restrictive elements, one can obtain a number of durations of action of shock pulses in a wide range, which will significantly expand the operational capabilities of braking devices. The invention of the brake device to the test bench for the author. St. No. 567109, characterized in that, in order to increase the reproduction accuracy of a given pulse shape and enhance the control of the pulse shape, the masses are made with axial projections and counter grooves and are equipped with interchangeable restraining elements installed in the grooves, the rigidity of which is greater than the stiffness of the dampers but less than the rigidity masses, and between the restrictive element of each mass and the protrusion of the previous mass there is an axial gap, the value of which is less than the maximum amount of compression of the damper, is placed on between the masses. Sources of information taken into account in the examination 1. US patent number 3.402.593, cl. 73-12, 1966. 2. USSR author's certificate number 567109, cl. G 01 M 7/00, 1975 (prototype).