RU202259U1 - Pneumatic jack hammer - Google Patents

Abstract

The utility model relates to the mining industry and construction, in particular to pneumatic hammers. The pneumatic jack hammer contains a handle, fixed with the ability to move relative to the barrel, in which there is a central channel and openings for air passage, an intermediate link with an annular chamber formed by an internal bore, a valve, an air distribution mechanism, a striker made with the ability to provide reciprocating movements and dividing the barrel into working and idle chambers, a damping ring made of an elastic polymer material, located inside the handle cavity. A porous chrome-plated coating with a thickness of 50 microns is made on the working surface of the barrel. The technical result is to increase the durability of the barrel to increase labor productivity. 1 ill.

Description

Technology area

The utility model relates to the mining industry and construction, in particular to pneumatic hammers.

State of the art

Known pneumatic jackhammer (Patent RU 168881, IPC B25D 17/24 (2006.01). Published 02.22.2017 Bull. No. 6), containing a handle, fixed with the ability to move relative to the barrel, which has a central channel and openings for air passage, intermediate a link with an annular chamber formed by an internal bore, a valve, an air distribution mechanism, a striker designed to provide reciprocating movements and dividing the barrel into working and idle chambers, a damping ring made of an elastic polymer material placed inside the handle cavity, while made in the form of a cylinder with a central hole and tapering towards the intermediate link of the end part [1].

The disadvantages of this pneumatic hammer are the low reliability of the barrel.

Known device is an internal combustion engine with a reciprocating piston with at least one cylinder (patent RU2011 122 113 A IPC F02F 3/00 Published: 10.12.2012 Bul. No. 34), and each cylinder has a cylinder liner and a piston located in it for reciprocating movement, while the piston has at least one piston ring on the surface of its jacket, and the materials of the cylinder liner and piston rings of the piston, which moves along the working surface of the cylinder liner, are ideally matched to each other along resistance to wear, while the piston rings have a coating made of chromium ceramics, at least on the surface facing the working surface of the cylinder liner, and the cylinder liner contains a solid phase fraction from 0.01 to 1.99% [2].

The disadvantages of this internal combustion engine are the low reliability of the cylinder.

Known device pneumatic jackhammer (patent RU 185 520 U1 IPC B25D 17/24; B25D 17/02 Published: 07.12.2018 Bul. No. 34), containing a handle, fixed with the ability to move relative to the barrel, which has a central channel and holes for air passage, an intermediate link with an annular chamber formed by an internal bore, a valve, an air distribution mechanism, a striker capable of providing reciprocating movements and dividing the barrel into working and idle chambers, a damping ring made of an elastic polymer material located inside the cavity handle, while made in the form of a cylinder with a central hole and tapering towards the intermediate link of the end part, and the striker is coated with damping materials nickel and fluoroplastic-epoxy varnish [3].

The disadvantages of this pneumatic jackhammer are low barrel reliability.

Disclosure of a utility model

The technical result of the utility model is to increase the wear resistance of the barrel to increase labor productivity.

The problem is solved by the fact that a pneumatic jackhammer, containing a handle fixed with the ability to move relative to the barrel, in which there is a central channel and holes for air passage, an intermediate link with an annular chamber formed by an internal bore, a valve, an air distribution mechanism, a striker made with the ability to provide reciprocating movements and dividing the barrel into the working and idle chambers, a damping ring made of an elastic polymer material, located inside the handle cavity, while made in the form of a cylinder with a central hole and tapering towards the intermediate link of the end part, and on the working surface of the barrel is made of a porous chrome-plated coating 50 µm thick.

The hallmark is:

a porous chrome-plated coating is made on the working surface of the barrel, such a technical solution makes it possible to increase the wear resistance of the cylinders and increase labor productivity by changing the overhaul period;

porous chrome-plated coating with a thickness of 50 microns, this contributes to an increase in tool life

A significant increase in the wear resistance of the rubbing surfaces of the barrel cylinder walls is achieved by using the processes of porous chromium plating [4].

Porous chrome coatings have a slightly higher ductility than shiny ones, they are easier to wear in, they more easily perceive local overloads during operation, and are characterized by high wear resistance and antifriction properties [5].

When the thickness of the electrolytic chromium layer is more than 50 microns, no progressive pore growth occurs. At 50 µm, the chrome plating cracks randomly and the crack pattern increases. As a result, several cracking layers are formed, lying one on top of the other, while pores appear in the coating as a result of intersecting cracks.

Comparison of the proposed solution with analogs and the prototype did not allow to identify in them the features that distinguish the proposed solution, which allows us to conclude that the criterion of "novelty" is met.

Brief Description of Figures

The claimed utility model is schematically shown in Fig., Which contains: 1 - barrel; 2 - porous chrome plating coating 50 microns thick.

Implementation of the utility model

The manufacturing technology of the proposed device is similar to the manufacturing technology of the known pneumatic jackhammer barrel. The processing of the cylindrical surface of the barrel 1 is performed by electrotechnical application of chrome coating 2. The optimal conditions for obtaining chrome coatings with the most developed network of cracks are:

the ratio Cr03: SO42. - (105-110): 1;

cathode current density during chromium plating iK - 40-60 A / dm ² ;

electrolyte temperature 55 ± 3 ° С;

holding time during anodic treatment - 5-12 minutes;

anode current density ia = 40-60 A / dm ² .

A decrease in the cathode current density causes the formation of a denser network of porous chromium channels, however, the width and depth of the channels becomes smaller. With an increase in the temperature of the electrolyte and the ratio of CrO3: SO42, the network of channels in the coating becomes more rare [5].

An increase in labor productivity is achieved by reducing the wear of the barrel 1 of the piston part of the working and idle chambers, since this coating has an aggregate antifriction property, and an increase in the overhaul period.

Sources of information

1. Patent RU 168881, IPC B25D 17/24 (2006.01). Published on February 22, 2017 Byull. No. 6.

2. Patent RU2011 122 113 A IPC F02F 3/00 Published: 10.12.2012 Byull. No. 34.

3. patent RU 185 520 U1 IPC B25D 17/24; B25D 17/02 Published: 07.12.2018 Bul. No. 34.

4. LLC "Sibstream" Chrome plating. [Electronic resource]. URL: https: //sibstream.rf/a154023-hromirovanie.html.

5. Physicochemical processes in mechanical engineering technology: a tutorial. [Electronic resource]. URL: http://window.edu.ru/catalog/pdf2txt/243/67243/40286?p_page=9.

Claims (2)

Pneumatic jack hammer, containing a handle, fixed with the ability to move relative to the barrel, which has a central channel and holes for air passage, an intermediate link with an annular chamber formed by an internal bore, a valve, an air distribution mechanism, a striker made with the ability to provide reciprocating movements and dividing the barrel into chambers of working and idle strokes, a damping ring made of an elastic polymer material placed inside the handle cavity, while the damping ring is made in the form of a cylinder with a central hole and an end part tapering towards the intermediate link, characterized in that on the working the surface of the barrel is made of a porous chrome-plated coating 50 µm thick.

Images