SU659739A1 - Air hammer - Google Patents

Description

one

The invention relates to the field of mining and construction percussion machines and can be used to create manual pneumatic hammers with valveless air distribution and stepped impactors, as well as heavy air percussion machines for the destruction of rocks and frozen ground.

Known manual pneumatic hammers with valveless air distribution and stepped drummers. These hammers are simple in design, durable, and have high operational reliability, including when operating in freezing temperatures. The central channel of the body of these hammers is divided by a hammer into three or more chambers, which makes it possible to obtain, under certain conditions, the most favorable characteristics of the resultant forces accelerating the hammer. In addition, stepped impactors allow one of the chambers with a constant network pressure to be realized in the hammers, which guarantees a steady start of the machines in operation 1.

The disadvantages of these hammers are: low energy of a single blow due to insufficient filling of the working stroke chamber with energy when the drummer is moving to the tool, as well as large pressure peaks in the working chamber at the dead end and the beginning of the stroke of the impactor, which cause vibration and require great effort on the handle hammer weave.

The closest technical solution to the proposed invention is a pneumatic hammer with a stepped drummer, in which the disadvantages noted are largely eliminated. This pneumatic 1st hammer contains a 1t case with air inlet, exhaust and central stepped channels, in which a stepped stepper with axial, radial and throttle channels is installed with the possibility of reciprocating movement, forming with the body a working stroke chamber, an idling chamber constantly communicated with a compressed air source, an accumulation chamber and an atmospheric pressure chamber, a handle and a working tool 2.

The design of this hammer allows you to increase the average air pressure in the working stroke chamber when the striker moves in the direction of the tool. As a result, the energy of a single blow increases substantially. The vibration and power characteristics of a pneumatic hammer are also improved.

However, the filling of the working stroke chamber and the average air pressure in it during the working stroke of the impactor remain insufficient in this hammer.

The aim of the invention is to further increase the energy of a single blow by increasing the air pressure in the working stroke chamber during the working stroke of the impactor.

This is achieved by the fact that the throttle channels of the striker are made on its steps of a larger diameter and constantly communicate the working and idling chambers among themselves.

The drawing shows an inevmatic hammer, a longitudinal section through the body.

The hammer includes a housing 1 with a central stepped channel in which a stepped drummer 2 with an axial 3 and 4 radial channels is installed with the possibility of reciprocating mixing, a handle 5 with a starting device (not shown) and a working tool b with a device 7 for its hold.

The housing 1, except for the central one, is provided with an air supply with shi 8 and exhaust 9 channels closed by a split ring 10.

The drummer 2 forms with the walls of the housing 1 a chamber AND working stroke, a chamber 12 of idling, which is constantly communicated when working with a source of compressed air, a chamber 13 of atmospheric pressure and an accumulation chamber 14.

In the stage of the impactor 2, which has a larger diameter, the throttle channels 15 are made, the working chambers 11 and the idling 12 strokes constantly communicating among themselves. The accumulator chamber 14 is periodically connected with the camera AND of the working stroke by means of the channels 3 and 4 of the striker 2. The latter, via the same channels, but in the reverse sequence, also periodically communicates with the chamber 13 of atmospheric pressure. Chamber 13 by means of exhaust ducts 9 is permanently connected with the atmosphere, and chamber 14 is constantly separated from the atmosphere. Chamber 12 periodically (during the exhaust period) communicates with the atmosphere through throttle channels 15, channels 3 and 4 of the striker 2, camera 13 and channels 9. When the starter is turned on, camera 12 is constantly in communication with the compressed air network.

Pneumatic hammer works as follows.

After switching on the trigger 5 of the handle 5, compressed air will flow through channels 8 into chamber 12. Pressure of compressed air on annular end 16 of drummer 2 from chamber 12 will cause the impactor to move from tool 6 - idling starts.

At the beginning of idling, the impactor 2 does not experience counterpressures from the side of chamber 11, since the pressure in it (despite the supply of network air from chamber 12 through throttle channels 15) is atmospheric, because at this time chamber 11 is communicated through channels 3 and 4 of drummer 2 with the camera 13, and through the exhaust channels 9 - with the atmosphere.

After blocking the radial channel 4 of the striker with the wall 17 of the housing 1, the pressure of the air cut off in the chamber And will begin to increase. Immediately thereafter, the chamber AND via the channels 3 and 4 of the striker communicates with the accumulation chamber 14, the additional volume of which will ensure a smooth increase in the counterpressure in the chamber AND, eliminating the appearance of sharp "nicks". The smooth growth of the back pressure in the chamber 11 and the accumulation chamber 14 also contributes to the flow of network air from the chamber 12 through the throttle channels 15. Due to the significant axial flow area of the axial 3 and the radial 4 impactor channels, the pressure in the chambers 11 and 14 is constantly equalized their messages.

As the backpressure chamber 11 increases, the movement of the firing pin slows down. At some point, the accumulator chamber 14 with air leaking into it is disconnected from chamber I, and the latter immediately immediately communicates channels 3 and 4 with chamber 12. Compressed air from chamber 12 enters chamber I. Due to the difference in pressure forces acting on the larger end and the annular end 16 of the striker 2, the latter will begin an accelerated movement in the direction of the tool, making a working stroke. The radial channel 4 of the striker 2 first overlaps with the wall of the housing, and then re-opens from the side of the accumulation chamber 14, as a result of which it communicates with the chamber 11, and the air accumulated in it maintains the pressure in this chamber at a higher level. To a even greater degree of maintaining high pressure in the chamber 11 at the working stroke, the flow of network air from chamber 12 through the throttle channels 15 contributes to it. In addition, throttling allows you to somewhat unload 12, which reduces the back pressure on the firing pin and further increases (compared to with a prototype) single impact energy.

In the period preceding the exhaust from chamber I, the radial channel 4 overlaps the wall of the housing 17, and the accumulation chamber 14 is uncoupled with camera I. After this, channel 4 of the impactor is opened from the side of chamber 13, and from chamber AND by channels 3 and 4 of the impactor, camera 13 and channel 9 exhaust occurs in the atmosphere. Due to significant

the flow area of the channels 9, the pressure in the chamber 13 during the exhaust period remains close to atmospheric.

Overcoming the resistance of the compressed air from the side of the annular chamber 12, the striker 2, after exhausting from chamber 11, will strike the tool shank b, and the cycle described above will repeat with the difference that the new cycle will start with the existing overpressure in the accumulation chamber 14 (0.4 -0.6 from the mains), since no air is released from it during the exhaust period.

During the communication period of the chamber I with the atmosphere, unproductive leakage of network air from chamber 12 through throttle channels takes place (in the prototype, similar leaks are observed from the accumulation chamber). However, as the calculations showed, this unproductive expenditure will be no more than 2-5% of the total, which is permissible.

Due to the better filling of the working stroke chamber with net air, the energy of a single blow in this hammer in comparison with the prototype increases substantially. In addition, the vibration force characteristics of the hammer are also slightly improved.

Claims (2)

1. German patent number 117560, cl. 87 in 2/09, published 1901. 2. For 2425238/03, cl. E 21C 3/24, 1977, according to which a decision was made to issue an author's certificate. 7/7