SU658268A1 - Pneumatic hammer - Google Patents

Description

The invention relates to construction and rock percussion machines and can be used to create hand-held pneumatic hammers with valve-less air distribution, as well as heavy air-impact machines for breaking frozen soils and rocks. Known manual pneumatic hammers with valveless air distribution and stepped drummers. 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, for specific conditions, the most favorable characteristics of the resultant forces accelerating the hammer. In addition, the foam impactors allow one of the chambers with the same net pressure to be realized in the hammers, which guarantees a steady start of the machines. Work 1. The disadvantages of such hammers are the increased specific consumption of aether air due to insufficient filling of the working stroke chamber with the energy carrier while moving the striker to the tool to large pressure peaks in the working chamber at the end of idle and beginning of the stroke of the striker causing vibration and requiring more effort to handle. The closest in technical essence and the achieved result to the invention is a pneumatic hammer, comprising a housing with a central stepped channel, in which with the possibility of reciprocating axial movement a stepped impactor with axial and radial channels is installed, forming with the walls of the housing a working stroke chamber, an idle chamber stroke, which is constantly in communication with a source of compressed air, an atmospheric pressure chamber and an accumulation one. , air supply and exhaust ducts, a handle and a working tool 2. In the hammer it was possible to increase the average air pressure in the working stroke chamber while moving the impactor towards the tool, as a result of h: it increased the energy of a single blow. The consumption of compressed air also increased slightly, but to a lesser extent than the energy of a single blow. As a result, the specific air flow rate in this hammer is quite high, and the vibration and power characteristics are also improved.

The aim of the invention is to reduce the specific consumption of compressed air.

This is achieved by the fact that throttle channels are made in the wall of the housing separating the chamber and the idling chamber to constantly communicate these chambers with each other.

In the drawing: e shows the proposed pneumatic hammer, a longitudinal section.

The hammer includes a housing 1 with a central stepped channel in which a step drummer 2 with axial 3 and 4 radial channels is installed with the possibility of reciprocating axial movement, a handle 5 with a starting device and a working tool 6 with a device 7 for holding it. The housing 1 is provided with air inlet 8 and exhaust 9 channels, which are closed by a split ring 10.

The drummer 2 forms with the walls of the casing 1 a working stroke chamber 11, an idling chamber 12 continuously communicated during operation with a source of compressed air, an atmospheric pressure chamber 13 and an accumulation chamber 14.

In the wall 15 of the housing 1, which separates the accumulation chamber 14 and the chamber 12, throttle channels 16 are made, which constantly communicate between these cameras. Cameras 14 and 12 through the channels 4 and 3 of the striker 2 periodically communicate with the camera 11 Last by the same channels, but in the reverse sequence, also periodically communicate with chamber 13. Chamber 13 is continuously connected with the atmosphere through exhaust channels 9, and chambers 12 and 14 are constantly separated from the atmosphere. When the starter is turned on, the chamber 12 is constantly communicated via the channels 8 with the compressed air network.

Pneumatic hammer works as follows.

After turning on the starting device of the handle 5, the compressed air enters through channels 8 into chamber 12. The pressure of compressed air at annular end 17 of the striker 2 from the side of chamber 12 causes the striker to move from tool 6 - it starts to move. At the beginning of idling, the udanik 2 does not experience a counterpressure from the chamber 11 side, since at that time it is in communication with the atmosphere through channels 3 and drummer 2, chamber 13 and exhaust channels 9. From the moment the starter turns on, the network air from the chamber 12 through the throttle channels 16 begins to flow into the accumulation chamber 14, increasing the pressure in it.

After the radial channel 4 of the striker 2 is blocked by the case wall 18, the pressure of the air cut off in the chamber 11 increases. After a short period of time, the channel 4 of the striker is opened from the side of the accumulation chamber 14 and the air from it enters the chamber 11, abruptly increasing the back pressure on the impactor 2. However, the back pressure jump is relatively small, since at the time the Accumulation chamber 14 communicates with the chamber 11 the latter is several (3-4) times larger than the volume of the accumulator chamber. Therefore, a marked back pressure jump in chamber 11 at the beginning of idling does not lead to deterioration of the vibration parameters of the hammer. With further movement of the firing pin, the back pressure on it from the side of the chamber 11 increases intensively, but smoothly. This contributes to the continuous leakage into the chamber 11 of the network air through the channels 16, the chamber 14 and the channels 4 and 3 of the drummer. Thanks to the significant axial flow area

3 and the radial 4 channels of the striker, the pressure in the chambers 11 and 14 is constantly equalized during the entire period of their communication.

As the backpressure chamber 11 increases, the movement of the striker slows down, at some point the channel

The striker overlaps the wall.

The housing 15, and the accumulation chamber 14, into which the network air continues to flow from chamber 12 through the throttle channels 16, is disconnected to the chamber 11. By the time channel 4 is opened from the chamber 12 side, the backpressure in the chamber 11 due to air leaking through the throttle channels 16 commensurate with the network pressure (0.7 - 0.8 network). As a result, the entry of network air from chamber 12 into chamber .11 through open channels 4 and 3 of the impactor does not cause such a sharp pressure peak in chamber 11 as it takes place at the end of idle and the beginning of the stroke in known pneumatic impact machines with stepped impactors.

Claims (2)

Due to the difference in pressure forces acting on the larger end and the annular end 17 of the impactor 2, after a stop, it begins to accelerate towards the tool, making a working stroke. The radial channel 4 first overlaps with the wall 15 of the housing, and then re-opens from the side of the accumulation chamber 14, as a result of which the latter communicates with the chamber 11. The air accumulated in the chamber 14 with or near pressure from the network enters the chamber 11 This will condition it to maintain a higher pressure at the working stroke. Maintaining a higher pressure in the chamber during operation and the throttle channels 16, through which the network air from chamber 12 continues to flow into the chamber 14 and from it to the chamber 11, promotes. A higher average pressure on the firing pin during the working stroke provides a proportional increase in energy single strike. In addition, throttling allows the chamber 12 to be somewhat relieved, which slightly reduces the amount of back pressure on the hammer from the side of the annular end 17 and further increases the energy of a single blow. In the period preceding the exhaust from the chamber 11, the radial channel 4 overlaps the housing wall 18 and the accumulation chamber 14 is uncoupled with the camera 11. Thereafter, the channel 4 of the striker 2 is opened from the side of the camera 13 and from the chamber 11 by means of the channels 3 and 4 of the impactor, camera 13 and Channel 9 exhaust into the atmosphere. Due to the significant flow area of the channels 9, the pressure in the chamber 13 during the exhaust period remains close to atmospheric. Having overcome the resistance of compressed air from the side of the annular chamber 12, the drummer 2 strikes the tool 6 shank after the exhaust and the cycle repeats with the difference that it starts when there is already considerable pressure in the chamber 14 (0.7 - Ou8 from the network), Since the network air from the chamber 12 continues to continuously flow into the chamber 14 through the channels 16. The proposed pneumatic milk allows, in comparison with the known, to use a larger amount of air in the working process. However, a significant portion of this air is retained in the accumulation chambers 14 for use in the E following cycle due to the absence of exhaust from it. The absolute consumption of compressed air per cycle can increase slightly, it increases the energy of a single blow much more intensively. As a result, the specific consumption of compressed air is reduced. In addition, the frequency of impacts increases and, while maintaining power, the dimensions and weight of the hammer are reduced by 10-14%; A pneumatic hammer comprising a housing with a central stepped channel in which a stepwise hammer with axial and radial channels is installed with reciprocating axial movement, forming a working stroke chamber with the housing walls, a no-load chamber constantly communicating with a source of compressed air, an atmospheric pressure chamber and an accumulation chamber, air supply and exhaust ducts, a handle and a working tool, characterized in that, in order to reduce the specific Flow rate of compressed air in the housing wall separating the battery-insulating chamber and idling, throttle channels formed for the permanent messages between these chambers a. Sources of information taken into account in the examination 1. German Patent No. 117560, cl. 87c 2/09, 1901. 2. For 2425238/03, cl. E 21 C 3/24, 19,11.77, according to which a decision was made to issue an author's certificate.