RU2410234C2 - Air hammer - Google Patents

Abstract

FIELD: machine building.

SUBSTANCE: air hammer consists of hollow cylinder with outlet channel, of striker dividing cavity of cylinder to chambers of working and idle strokes with inlet channels, of handle with devices for inlet and air distribution between chambers, of inlet chamber with air fending jacket and inlet channel and of operating tool with shank end. An intermediate stepped anvil is positioned between the striker and the shank end of the operating tool. A chamber of an air buffer is located on the side of less step of the anvil. From the side of a bigger step of the anvil there is arranged a circular network camera communicated with the distribution device in the handle with inlet channel in a wall of the cylinder. The middle step of the anvil with its end area faces the chamber of the idle stroke. Also, the middle step of the anvil has an air-escape channel with an outlet into the idle-stroke chamber and inlet on a section of side surface, this inlet is periodically overlapped with the cylinder from the side of the circular network camera.

EFFECT: decreased specific consumption of air and raised efficiency of device.

8 cl, 7 dwg

Description

The pneumatic hammer belongs to the field of construction and mining equipment for the development of strong materials of natural and artificial origin.

Known pneumatic hammer (see, for example, the USSR AS No. 95534, Ml. B25D 9/00, E21C 3/24, E21C 37/2, 1953), containing a hollow cylindrical body, housing cover and guide cover a step intermediate anvil, a step striker dividing the body cavity into the network, working and idle cameras, a working tool with a shank installed in the guide, bolted to the body, and the air inlet into the chambers is controlled by a step striker. A stepped intermediate anvil is located between the hammer and the tool shank.

The specified technical solution has disadvantages: the anvil with a lower step faces the idle chamber; there are no air distribution elements that control the position of the anvil; the drummer as an air distributor has a dependence of the stroke on its length, which leads to low maneuverability, a significant specific mass of scrap per unit of its impact power.

Also known is a technical solution for pneumatic concrete breaker (see, for example, UK patent No. 908883, Ml. B25D, 1962) containing an intake device, an air distribution device between the chambers, a noise protection device, a vibration protection device, a working tool with a shank and a device for holding it , a hollow cylinder with an additional cylinder movable relative to the cylinder, a striker dividing the cylinder cavity into working and idle chambers, an intermediate step anvil located between the hammer and the shank of the working tool, the pneumatic buffer chamber from the side of the large anvil stage, the annular chamber from the side of the lower anvil stage, communicated with the air distribution device, the lower stage of the anvil with its end area facing the idle chamber, with the larger and smaller stages joined by a longitudinal groove without exit to their end surfaces, and the groove interacts with the air distribution channel.

The indicated technical solution has a drawback: the annular chamber formed by the cylinder and the steps of the intermediate anvil is not communicated with the idle chamber and does not participate in the formation of a force pulse of air pressure from its side; the intermediate anvil is always in the position of bearing on the shank of the working tool, and therefore, significantly increases the stroke of the striker under counter pressure from the side of the idle chamber, as a result of which the loss of kinetic energy of the striker before the strike and the stroke time increase, which determines the decrease in the frequency of strikes. In addition to the aforementioned, the disadvantages of this technical solution include multi-detail, which, as a rule, leads to a decrease in the reliability and resource of the device as a whole.

A technical solution is known for a pneumatic hammer (see, for example, Swedish patent No. 358332, Ml. B25D 9/01, 1973), including a hollow cylinder with an exhaust channel, a hammer, dividing the cylinder cavity into working and idle chambers with inlet channels, a handle with inlet and air distribution devices between the chambers, an exhaust chamber with an air guard and an exhaust channel, a working tool with a shank, an intermediate step anvil located between the hammer and the shank of the working tool, a pneumatic chamber buffer from the side of the lower stage of the anvil, the annular network chamber from the side of the higher stage of the anvil, communicated by the inlet channel in the cylinder wall with the intake and air distribution device in the handle, the middle stage of the anvil, with its end area facing the idle chamber.

The specified technical solution of the pneumatic hammer is taken as a prototype, as containing the largest number of essential features common with the claimed technical solution.

The prototype is characterized by a main drawback: the annular chamber from the side of the larger anvil stage is not communicated with the idle chamber and does not participate in the formation of a force impulse of air pressure from its side. This determines the inlet of a significant amount of air into the idle chamber in the pre-shock period; the formation of significant backpressure and braking of the projectile and, as a consequence, a decrease in its kinetic energy transmitted to the intermediate anvil and further to the shank of the working tool and the medium being processed. This consumes a significant amount of air supplied to the idle chamber, which seems possible to reduce due to its supply only for launch purposes.

The disadvantage of the prototype is eliminated if the annular chamber communicated with the compressed air network is periodically communicated with the idle chamber, and the main channel of the air inlet into the idle chamber is used as the launch channel.

The essence of the proposed technical solution is as follows.

The pneumatic hammer contains a hollow cylinder with an exhaust channel, a hammer that separates the cylinder cavity into working and idle chambers with inlet channels, a handle with intake and air distribution devices between the chambers, an exhaust chamber with an air guard and an exhaust channel, a working tool with a shank, an intermediate step anvil located between the drummer and the shank of the working tool, the pneumatic buffer chamber on the side of the lower anvil stage, the annular network chamber on the side the larger stage of the anvil, communicated by the inlet channel in the cylinder wall with the air distribution device in the handle, the middle stage of the anvil, with its end area facing the idle chamber, and the middle stage of the anvil is equipped with a bypass channel with an exit to the idle chamber and an entrance on the side of the middle surface steps periodically blocked by a cylinder from the side of the annular network camera.

It is advisable to bypass channel in the form of a direct groove with a constant passage section.

It is advisable to make the bypass channel in the form of an inclined groove with an increasing bore in the direction of the idle chamber.

It is advisable to make the bypass channel in the form of a straight line with a constant bore.

It is advisable to make the bypass channel in the form of an inclined flat with an increasing bore in the direction of the idle chamber.

It is advisable to make the bypass channel in the form of an inclined circular channel in the cross section in the body of the anvil stage.

It is advisable to make the bypass channel in the form of a truncated cone, expanding towards the idle chamber.

It is advisable to bypass channel in the form of a cranked channel in the body of the middle stage of the anvil.

The objective of the proposed technical solution is to reduce the specific air consumption and increase the efficiency of the hammer.

The proposed technical solution is illustrated by drawings. Figure 1 shows a pneumatic hammer with a partial longitudinal section with the implementation of the bypass channel in the stage of the anvil in the form of a direct groove with a constant passage section; figure 2 is a fragment of the bypass channel in the form of an inclined groove with an increasing bore in the direction of the idle chamber; figure 3 is a fragment of the bypass channel in the form of a direct flat; figure 4 is a fragment of the bypass channel in the form of an inclined flat with an increasing bore in the direction of the idle chamber;

figure 5 is a fragment of the bypass channel in the form of an inclined circular in cross-section of the channel in the body of the stage; Fig.6 is a fragment of the bypass channel in the form of a truncated cone, expanding towards the idle chamber; 7 is a fragment of the bypass channel in the form of a cranked channel in the body of the stage. In all the drawings, the designations are assumed to be the same.

The pneumatic hammer contains a hollow cylinder 1 with an outlet channel 2, a hammer 3, a working chamber 4 with an inlet channel 5 and an idle chamber 6 with a calibrated inlet channel 7, a handle 8 with intake and air distribution devices between the chambers (not shown and can be any known constructions), an exhaust chamber 9 with an air guard 10 and an exhaust channel 11, a working tool 12 with a shank 13, an intermediate step anvil 14 located between the hammer 3 and the shank 13, the pneumatic chamber 15 buffer from the side of the lower stage 16, the annular network chamber 17 from the side of the higher stage 18, communicated by the inlet channel 19 in the wall of the cylinder 1 with the air distribution device in the handle 8, the middle stage 20 of the anvil 14, with its end area 21 facing the chamber 6, the bypass a channel in the form of a direct groove 22 (FIG. 1), or an inclined groove 23 (FIG. 2), or a straight flange 24 (FIG. 3), or an inclined flat 25 (FIG. 4), or an inclined circular channel 26 in cross section ( 5), or a conical channel 27 (6), or a cranked channel 28 (7) with an output of 29 the chamber 6 and the inlet 30 on a portion of the side surface 31 of the anvil stage 20, periodically blocked by the cylinder 1 from the side of the annular network camera 17.

Air hammer works as follows.

When you press the handle 8 and turn on the intake and air distribution device, air simultaneously enters through the calibrated launch channel 7 into the idle chamber 6 and through the intake channel 19 into the annular network chamber 17. In the position shown in Fig. 1, the chambers 6 and 17 communicate between by means of a bypass channel in the form of a groove 22 or an inclined groove 23 (Fig. 2), or a straight flat 24 (Fig. 3), or an inclined flat 25 (Fig. 4), or a circular inclined channel 26 (Fig. 5) either a conical channel 27 (Fig.6), or a cranked channel 28 (Fig.7), with in output 29 and input 30. Due to the larger area from the side of the larger stage 18 and the lower air pressure to the end area 21, from the side of the chamber 6, due to the smaller air intake through the calibrated launch channel 7, the step anvil 14 together with the hammer 3 will begin to move to the side of the handle 8 to the stop of the larger stage 18 at the end of the cylinder 1, blocking the bypass channel, after which the anvil 14 will stop in the position shown in figure 2, 3, 4, 5, 6 and 7, and the hammer under the action of an air pressure pulse side camera 6 will be about keep movement, blocking the exhaust channel 2. As a result, the air pressure in the chamber 4 of the working stroke will increase, and the air distribution device will open air from the network through the inlet channel 5 to the chamber 4. With further movement, the hammer 3 will open the channel 2 from the side of the chamber 6 and from it air through channel 2, the exhaust chamber 9, the exhaust channel 11 will be removed to the atmosphere. The air pressure in the chamber 6, despite some of its flow through the calibrated launch channel 7, will be close to atmospheric, which is facilitated by a significantly larger passage section of the channel 2 in comparison with the section of the channel 7. Having exhausted the initial pulse of air pressure from the side of the chamber 6, the hammer 3 will stop and will begin its movement towards the stepped anvil. After the drummer 3 closes the exhaust channel 2 in the chamber 6, the compression of the air cut off in it and the air entering through the calibrated launch channel 7 will begin. The air pressure in the chamber 4 will decrease, and the air distribution device will close its access to the channel 5 and the chamber 4. Since the air pressure in the chamber 6 is not large due to the small passage area of the launch channel 7, the hammer 3, overcoming the backpressure force, will strike the anvil 14 The calculated value of the impact force from the side of the hammer 3 is determined by the kinetic energy possessed by the hammer and the force of air pressure on the end area 21 from the side of the chamber 6. The sum of the indicated forces is greater than the sum of the forces holding the anvil 14 in position II, shown in figure 2, 3, 4, 5, 6 and 7, due to air pressure on the site of the larger stage 18 from the side of the chamber 15 of the pneumatic buffer acting on the site of the lower stage 16 of the anvil. Under the action of a greater force from the side of the chamber 6, the anvil 14 together with the striker 3 will move towards the shank 13 of the working tool 12 until it collides with the shank, as a result of which the kinetic energy of the impact from the moving masses of the striker and the anvil will be transferred to the working tool and the processed medium.

During the opening of the bypass channel in the form of a direct groove 22 (Fig. 1), the chambers 6 and 17 will communicate and a portion of a significant amount of air accumulated in the chamber 17 will flow into the chamber 6. Under the influence of a significant pulse of air pressure, the hammer 3 will disconnect from the anvil 14 and will begin accelerated movement towards the handle, making idle, which will contribute to the pressure of the air flowing into the chamber 6 through the channel 7 launch. With further movement, the hammer 3 will block the exhaust channel 2, and in the chamber 4, the compression of the air cut off in it will begin. After the drummer 3 opens the outlet channel 2 from the side of the chamber 6, the air pressure in the chamber will decrease and under the influence of significant air pressure forces to a large stage 18 from the side of the network chamber 17 and to a smaller stage 16 from the side of the chamber 15 of the pneumatic buffer, the step anvil will rapidly move from the shank 13 and will block the bypass channel in the form of a direct groove 22 (FIG. 1), or an inclined groove 23 (FIG. 2), or a straight flange 24 (FIG. 3), or an inclined flange 25 (FIG. 4), or an inclined channel 26 ( figure 5), or a conical channel 27 (figure 6), or lenchatogo channel 28 (Figure 7), and the chamber 17 and 6 open, and in the chamber 17 starts accumulation of air pressure to close the network.

In the current period of the cycle, the pressure in the chamber 4 will increase to the calculated value, and the air distribution device will open the air to the channel 5 and the chamber 4. Under the influence of backpressure from the side of the chamber 4, the firing pin will begin to slow down its movement, and having exhausted the impulse of pressure forces received from the side of the chamber 6, it will stop and immediately begin accelerated movement towards the anvil 14, making a working stroke.

Moving to the side of the anvil 14, the hammer will block the exhaust channel 2 from the side of the chamber 6 and it will begin to compress the cut-off air and air entering the calibrated launch channel 7. Note that when the chamber 6 is in communication with the atmosphere by means of channel 2, chamber 9, and channel 11 during periods of idle and stroke of the striker 3, the productive air flow is insignificant due to the small passage area of the calibrated launch channel 7. Further, during its movement, the firing pin 3 opens the exhaust channel 2, as a result of which the pressure in the chamber 4 decreases almost to atmospheric, since the passage section of the channel 2 is significantly larger than the passage section of the channel 5.

As a result of the aforementioned, the air distribution device immediately turns off the air supply to the channel 5 and the chamber 4.

Overcoming the resistance from air backpressure from the side of the chamber 6, the firing pin 3 strikes the anvil 14. The calculated value of the impact force from the side of the firing pin 3 is determined by the kinetic energy, which in the second collision cycle is much larger than in the launch cycle. Thus, the sum of the forces from impact and air pressure acting on the end area 21 from the side of the chamber 6 is significantly greater than the forces holding the anvil 14 in the position shown in Figs. 2, 3, 4, 5, 6, and 7, due to pressure air to the site of the larger stage 18 from the side of the chamber 17 and air pressure from the side of the chamber 15 of the pneumatic buffer acting on the site of the smaller stage 16 of the anvil.

Under the action of a greater force of air pressure on the end face 21 from the side of the chamber 6, the anvil 14 together with the striker 3 will move towards the shank 13 of the working tool 12 until it collides with the shank, as a result of which the kinetic energy of the impact from the moving masses of the striker and the anvil will be transferred to the working tool and processed environment.

During the opening of the bypass channel in the form of a direct groove 22 (Fig. 1), the chambers 6 and 17 are communicated, and a portion of a significant amount of accumulated air, with greater pressure than was the case in the start-up cycle, will flow into the chamber 6. Under the influence of a significant pressure pulse air, the hammer 3 will disconnect from the anvil 14 and begin accelerated movement towards the handle, making idle, which will also contribute to the pressure of the air flowing into the chamber 6 through a calibrated launch channel 7. The parameters of the energy and economic indicators of the second cycle will correspond in value to the parameters of the steady state operation of the pneumatic hammer. Next, the workflow will be repeated.

Thus, the execution of the bypass channel in the form of a direct groove (Fig. 1) between the network camera 17 and the idle camera 6, which functions during the collision of the hammer 3 with the anvil 14, allows for efficient air flow through the network camera, and reduce unproductive air flow for due to a significant reduction in the bore of the inlet channel into the idle chamber, leaving behind it mainly the launch functions, i.e. functions of the calibrated inlet channel 7 start.

The features of the proposed options for the structural design of the bypass channel in the area of the side surface of the middle stage between the chambers 17 and 6, taking into account the changing pressure in the chambers, are as follows.

The implementation of the bypass channel in the form of a direct groove (see figure 1) allows for air bypass at a constant flow section from the inlet and outlet of the air flow, which will provide the estimated air flow for the entire period of the bypass process.

The bypass channel in the form of an inclined groove with an expanding bore in the direction of the idle chamber (see figure 2) allows air bypass with a smooth increase and decrease in air flow during the start and end of the bypass process.

The execution of the bypass channel in the form of a straight flat (see figure 3) allows for air bypass with a constant passage section of the channel from the inlet and outlet of the air stream and to provide greater strength of the anvil in the cross section (compared with the direct groove) by reducing the number of concentrators voltages at the borders of the bypass channel.

The bypass channel in the form of an inclined flat (see figure 4) allows for air bypass with a smooth increase and decrease in air flow during the start and end of the bypass process and greater anvil strength in the cross section (compared with an inclined groove and a straight flat) of the stage by reducing the number of stress concentrators at the boundary of the bypass channel input.

The implementation of the bypass channel in the form of an inclined channel of circular cross section (see Fig. 5) allows for air bypass with a constant passage section on the inlet and outlet side of the channel, to reduce the number of stress concentrators at the boundaries of the bypass channel due to the oval shape of the channel openings, which allows to increase the strength anvils.

The bypass channel in the form of a conical truncated cone with an expanding bore at the inlet and outlet due to its oblique sections (see Fig.6) allows air bypass with a smooth expansion at the outlet, which will reduce the backpressure in the period preceding the impact of the projectile with a hard place.

The implementation of the bypass channel in the form of a cranked channel (see Fig. 7) allows air bypass with a constant passage section of the channel and a guaranteed estimated air flow for the entire period of the bypass process, which will ensure the stability of the operating mode at the end of the working and the beginning of the idle drum.

Variants of the design of the bypass channels in the section of the lateral surface of the middle stage (straight or inclined grooves, straight or inclined flats, inclined round sections or inclined conical or cranked) allow controlling the air bypass mode between chambers 6 and 17, which creates an additional positive effect when choosing air hammer operating mode.

Claims (8)

1. A pneumatic hammer containing a hollow cylinder with an exhaust channel, a hammer that separates the cylinder cavity into working and idle chambers with inlet channels, a handle with intake and air distribution devices between the chambers, an exhaust chamber with an air baffle cover and an exhaust channel, a working tool with a shank, an intermediate step anvil located between the drummer and the tool shank, a pneumatic buffer chamber on the side of the lower anvil stage, an annular network chamber on the side they are of a larger anvil stage communicated by the inlet channel in the cylinder wall with an air distribution device in the handle, the middle stage of the anvil facing the idle chamber, characterized in that the middle stage of the anvil is made with a bypass channel with an exit to the idle chamber and the entrance on the site of its lateral surface, periodically blocked by a cylinder from the side of the annular network camera. 2. The pneumatic hammer according to claim 1, characterized in that the bypass channel is made in the form of a direct groove with a constant bore. 3. The pneumatic hammer according to claim 1, characterized in that the bypass channel is made in the form of an inclined groove with an increase in the bore in the direction of the idle chamber. 4. The pneumatic hammer according to claim 1, characterized in that the bypass channel is made in the form of a straight line with a constant bore. 5. The pneumatic hammer according to claim 1, characterized in that the bypass channel is made in the form of an inclined flat with an increasing bore in the direction of the idle chamber. 6. The pneumatic hammer according to claim 1, characterized in that the bypass channel is made in the form of an inclined circular channel in the cross section in the body of the middle stage of the anvil. 7. The pneumatic hammer according to claim 1, characterized in that the bypass channel is made in the form of a truncated cone, expanding towards the idle chamber. 8. The pneumatic hammer according to claim 1, characterized in that the bypass channel is made in the form of a cranked channel in the body of the middle stage of the anvil.

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