UA137654U - PNEUMATIC HAMMER CHAMPION FOR STRENGTHENING WELDED JOINTS - Google Patents

Abstract

The chisel of a pneumatic hammer for strengthening of welded connections of a metalwork by their low-frequency shock processing is made in the form of the cylinder which working end part has a hemispherical surface, the tail part has a ledge for fixing a chisel by a spring in the case of a pneumatic hammer. the impact force of the bit on the machining hardware, designed for its electrical connection with the measuring device. The countersink is removable and is mounted on a movable fit in the guide sleeve, which has a U-shape in axial section and in which there is a through central hole for partial exit of the striker outside the sleeve, fixed by its lateral cylindrical section by threaded connection to the workpiece. and the area of the striker, located within the guide sleeve, rests on a roller mounted in a blind axial hole made from the end surface of the working part of the bit.

Description

The useful model belongs to devices for strengthening processing of welded joints of machine parts, metal elements of structures, which is carried out by repeated shock loading with a rod chisel.

The proposed useful model can be used in mechanical engineering, in the construction industry, in road construction and in bridge construction.

Surface strengthening of the fusion zone of the base metal with the weld metal is carried out in the mode of reciprocating movement with a frequency of 25-100 Hz of a working pneumatic hammer weighing 1.5-3.5 kg at an air pressure of 5-7 bar and an impact energy of 5-15 J (1 , pp. 18-19). Chisels, depending on the need for processing, are made in the form of cylindrical hardened rods with a hemispherical tip with a diameter of 3-18 mm and a length of 100-200 mm. The amplitude of the forward movement of the bit and, as a result, the force of its impact on the metalwork depend on the force of the pneumatic hammer pressed by the operator. Therefore, the efficiency of processing welded joints depends on the qualification of the operator. The main task in the creation of new tools for low-frequency impact treatment (LFA) of welded joints is the production of a bit with a lower cost, in particular with a lower cost for its replacement and higher productivity while meeting the requirements for the quality of processing.

In the case of a welded joint, if the tool is moved along the seam, a groove is created. Its quality (surface roughness, smoothness of the transition of the seam roller to the base metal in the zone of their fusion) and the impact force of the chisel, measured by the installed tensor, is controlled by the operator (2, p. 786-787). When the tip is worn, the operator dismantles the bit.

Because of this, the disadvantage of this bit is the need to periodically restore the geometric dimensions of its tip by mechanical processing. Therefore, the time spent on restoring the working capacity of the tool, namely on repositioning the bit, readjusting the tensometric system, restoring the required profile of the bit tip by mechanical processing increases the time of non-life of welded metal products.

The closest to the proposed one in terms of essential features is the chisel of the 5А8-9502ХРИ 5 ИЗ pneumatic hammer. It has the shape of a cylinder with a diameter of 12 mm, a length of 100 mm and is made of low alloy steel. The working part has a conical shape with a hardened hemispherical tip with a diameter of 3 mm, and the tail part has a protrusion for fixation

From the chisel spring in the body of the pneumatic hammer. A tensor |2, p. 788I is installed on the cylindrical surface to measure the impact force of the chisel on the metal structure.

The disadvantage of this bit is the need for its frequent replacement due to the loss of the desired profile of the tip. And this is accompanied by significant labor costs of time, which is associated with the performance of a number of technological operations to restore the operation of the bit, namely, repositioning the bit, readjusting the tensometric system, restoring the required profile of the bit tip by mechanical processing. The listed operations significantly reduce productivity and increase the cost of welding joints with the mentioned chisel.

The basis of the useful model is the task of creating such a design of the working part of the pneumatic hammer bit, which would allow to increase the productivity of welded joints and reduce its cost due to the use of the proposed removable striker in the design of the bit.

The task is solved by the fact that the bit of a pneumatic hammer for strengthening welded joints of metal structures by their low-frequency impact treatment is made in the form of a cylinder, the working end part of which has a hemispherical surface, the tail part has a protrusion for fixing the bit with a spring in the body of the pneumatic hammer, and on its on the side surface, a tension resistor is fixed for measuring the impact force of the chisel on the processed metalwork, designed for its electrical connection with the measuring device. The hammer is removable and mounted on a movable fit in the guide sleeve, which has a U-shaped shape in the axial section and in which there is a through central hole for the partial exit of the hammer outside the sleeve, fixed by its side cylindrical section with a threaded connection on the working part of the bit. and the part of the striker, located within the guide sleeve, rests on a roller installed in a blind axial hole made on the side of the end surface of the working part of the bit.

The drawing explains the essence of a useful model.

The proposed bit of a pneumatic hammer for low-frequency impact treatment of welded metal structures is made of low-alloy steel in the form of a cylinder with a diameter of 12 mm, a length of 100 mm, hardness of NAS 37-38. The working part 1 of the chisel is equipped with a striker 2 with a hemispherical surface. The tail part C of the bit has a protrusion 4 for fixing the bit with a spring in the body of the pneumatic hammer /not shown/. On the side cylindrical surface of the working part 1 of the bit, a tensor resistor 5 is fixed for measuring the impact force of the bit on the processed metal product. Tensor resistor 5 is connected to a measuring device, for example, an equal-arm Wheatstone bridge /not shown/. On the side of the end of the working surface 1, a blind hole is made, in which a roller 6 with a diameter of 10 mm, made of steel, is installed

IPH15 with a hardness of НАС 60 and fixed in the mentioned hole by a guide sleeve 7 with a hardness of НАС 60. The sleeve 7 has a U-shaped shape in the axial section, in which there is a through central hole for the partial exit of the striker 2 outside the borders of the sleeve 7. The sleeve 7 is fixed by its side a cylindrical section with a threaded connection on the working part of 1 bit. For reliable fixation of the guide bushing 7 on the bit, the design uses a lock nut 8 with a lock washer 9. A removable striker 2 with a hardness of НАС 60 with a hemispherical surface at the end, directly in contact with the processed metalwork, is installed on a movable fit in the hole of the guide bushing 7. The proposed design changes of the working parts of the chisel will allow to significantly reduce the duration and cost of the NGO, in particular, from St3 sp steel compared to machining with a prototype chisel.

The proposed chisel works like this.

During the operation of the pneumatic hammer, the chisel with its tail part Z slides in the body (in the sleeve) of the hammer, resting with the protrusion 4 on the spring, and the removable striker 2 on the processed metal product. During operation, the chisel is subjected to a cyclic shock load, which leads to a violation of the hemispherical surface of the striker due to plastic deformation of the steel from which it is made. But, due to the presence of roller b, which interacts on one side with the striker, and on the other - with the body of the bit, the level of mechanical stresses in the striker is significantly lower than the mechanical stresses in the prototype bit. This increases the resource of the offered bit. Taking into account the fact that the striker 2 is installed in the guide sleeve 7 on a movable landing, it is quickly replaced after losing the hemispherical shape. Thus, compared to the prototype, the proposed bit has increased productivity, allows to reduce the cost of strengthening treatment of welded joints due to the use of a removable striker in the design of the proposed bit.

Sources of information: 1. Naadepzep, R.). apa Madaoh, 5.9U.(2001) bresiiisaiop5 og Med Toe Itrhometepi Bu Witt

Sytipaipo, TI Ogezzipd apa Natteg Reepipd og Tgtapzuegze Meidv. PM/ bositepi, Sottivviop KhPP,

Mokipd Stoyr 2, M/S, Ipiegpaiiopai Ipviyshe oi M/eidipo.

Co., Ltd.) 2. Vgapso S.M. Raidne reNamiog oi meiaea |oipiv m/y steaskv, geraited Bu natteg reepipd /S.M.

Vgapso, U. Ipngapiye, V. Vapivia //Raijdice Egasi. Epapo. Maieg. running 2004. - M. 27, Mo. 9. - R. 785-798. 3. porz//rpeitotavieg.sot .tsa/gy/arotsi/. Professional pneumatic tools and pneumatic equipment. - Kyiv: PE "Pneumomaster" (official representative of AIVOIIMOO5TVI SORVR).

Claims (1)

USEFUL MODEL FORMULA Chisel of a pneumatic hammer for strengthening welded joints of metal structures by their low-frequency impact treatment, made in the form of a cylinder, the working end part of which has a hemispherical surface, the tail part has a protrusion for fixing the chisel with a spring in the body of the pneumatic hammer, and on its side a tensor resistor is fixed to the surface for measuring the impact force of the chisel on the processed metal product, intended for its electrical connection with the measuring device, which is distinguished by the fact that the striker is removable and installed on a movable fit in the guide sleeve, which has a U-shaped shape in the axial section and in which there is a through central hole for a partial exit of the striker outside the bushing, fixed by its side cylindrical section with a threaded connection on the working part of the bit, and the striker section located within the guide sleeve rests on a roller installed in a blind axial hole made on the side of the end surface of the working part of the bit.