RU2327871C2 - Pneumatic impact mechanism with throttling air distribution - Google Patents

Abstract

FIELD: mechanics.

SUBSTANCE: invention is related to construction and mining impact machines. Mechanism includes network air chamber, pre-chamber, hollow cylinder with striker splitting cylinder cavity into working and idle stroke chambers, lid with bead at one cylinder end from working stroke chamber side, tube with continuously opened inlet duct. Inlet duct connects pre-chamber with idle stroke chamber. Mechanism is also comprised of a cup with circular bead directed to lid bead, circular static boosting chamber in cylinder wall from the side of idle stroke chamber. Boosting duct in cylinder wall is in the form of radial channel connecting static boosting chamber with idle stroke chamber. Boosting duct connects also outlet ducts in cylinder walls and operating tool with tongue. Striker is provided with internal and external recessed chambers interconnected by bypass duct and so that the distance from cutoff edge of boosting duct shear to outlet duct is more than the length of external recessed chamber on striker. Side surface of tube is ensured with radial channel connecting internal recessed chamber in striker with longitudinal tube ducts. From the side of operating tool longitudinal duct of tube is provided with start-up throttle.

EFFECT: increase of impact effect to treated medium.

1 dwg

Description

The present invention relates to the field of construction and mining percussion machines and can be used to create manual pneumatic hammers for mechanical engineering, as well as heavy pneumatic impact machines for the destruction of rock and frozen soils.

A pneumatic hammer is known (see, for example, AS USSR No. 787632, MKl E21C 3/24, 1980) containing a working tool, a hammer with a channel opened from the side of the working chamber located on the side of the cylinder end opposite to the working one to the tool and from the side of the side, intake and exhaust channels with an annular recess in the cylinder and an idle chamber on the side of the working tool, communicated with each other by a channel in the cylinder, and the annular recess (chamber) from the outlet channel is in constant communication with the compressed air network and overlaps with the drummer periodically.

The indicated and similar technical solutions have disadvantages: the annular recess (chamber) and the idle chamber are constantly connected to each other, which causes significant back pressure from the side of the idle chamber and slows down the hammer, reducing its pre-shock speed and, consequently, the kinetic energy of the shock transmitted instrument; the channel in the drummer by means of a radial exit to its side surface before impact passes part of the air with significant pressure from the working chamber into the annular recess and through the channel in the cylinder into the idling chamber, which also contributes to an increase in back pressure in the idling chamber before the impactor strikes the tool; after impact, the channel in the drummer bypasses part of the air from the annular chamber and, therefore, the idling chamber into the working chamber with a lower air pressure in it, which significantly reduces the pressure impulse from the side of the idling chamber and does not provide the calculated value stroke, increases the idle time, reduces the frequency and energy of the impact.

Also known is a pneumatic shock device with throttle air distribution (see, for example, AS USSR No. 1235719, MKL B25D 9/14, 1986 - prototype), comprising a network air chamber, a pre-chamber, a device for switching on the supply of compressed air to the chamber air supply, a hollow cylinder, a drummer located in it, dividing the cylinder cavity into the idle and working chamber, an annular groove located on the side of the idle chamber and connected to it by a constant bypass channel mounted on one end of the cylinder with the orons of the working chamber are a lid with a shoulder, a tube with a flat channel on the side surface and a constantly open inlet channel connecting the pre-chamber to the idle chamber, a glass with an annular collar facing the lid shoulder, exhaust channels made in the side wall of the cylinder, and a working tool with a shank.

The specified pneumatic shock device with throttle air distribution adopted as a prototype as containing the largest number of essential features used in the proposed technical solution.

The prototype has disadvantages: a tube for supplying air to the idle chamber, which is rigidly fixed relative to the housing, which requires the execution of a cylinder, tube and drummer from one installation to ensure alignment of these parts, which is practically impossible, and three fittings of these parts relative to each other lead to warping, braking the drummer and breaking the tube; the message of the ring recess and the idle chamber through the bypass channel in the isthmus between the chambers increases the accumulation volume, which must be filled with air from the network through the throttle inlet channel in the tube, but this leads to braking of the hammer by creating significant back pressure in the idle chamber and ring groove at the end of the stroke, which leads to a loss of kinetic energy of the drummer, and at the beginning of idling after collision and an increase in the volume of the idle chamber and the air pressure impulse from the side of the idle chamber is insufficient to provide the estimated magnitude of the stroke of the striker, as a result of which the idle time increases and the frequency of impacts decreases with a significant irrational air flow from the network; the presence of a channel-groove (or flats) on the side surface of the tube in this technical solution leads to the selection of air from the idle chamber and passes it to the working chamber, which leads to a decrease in the air pressure impulse from the side of the idling chamber and, as a result, an increase in idle time and a decrease in the stroke of the projectile, and as a result, a decrease in the frequency and energy of the impact.

The noted disadvantages of the prototype as a whole reduce the effect of shock interaction with the medium being processed.

The technical problem solved by the invention is to increase the effect of impact on the medium being processed by reducing the volume of the idle chamber itself and securing the launch functions to the inlet channel in the tube, thereby significantly reducing the air flow from the network and lowering the back pressure in the idling chamber; securing to the annular recess (camera) the functions of the non-flowing afterburner camera and the message of its volume constantly by the inlet throttle with the network air chamber, thereby eliminating backpressure in the idle chamber; the exclusion of the bypass channel between the idle and working chambers in the form of a groove (or flat), which will preserve the idle pressure impulse, which after the idle chamber and the non-flow afterburner will increase significantly due to the connection of the air accumulated in it with a pressure close to the network pressure.

At the same time, it is necessary to block the afterburner channel, which informs the idle chamber and the slow afterburner during operation, at a certain section of the drummer’s movement, and open the message when idle. The aforementioned will allow not creating a significant air backpressure in the idle chamber before impact, and therefore, increase the speed of impact. During acceleration of the striker in the initial period of idling, the air pressure in the idle chamber due to its entry from the network chamber through the start channel in the tube will decrease slightly, and when the afterburner is opened, the pressure in the idle chamber will increase, and the striker will receive an additional pressure impulse and increase the speed his movement towards the lid. The aforementioned will reduce the time of movement of the drummer at idle.

Thus, in order to achieve the effect, it is necessary to report the afterburner chamber from the side of the idle chamber via the inlet channel in the tube with the network air chamber.

The problem is solved in that the pneumatic shock device with throttle air distribution includes a mains air chamber, a pre-chamber, a device for turning on compressed air into the mains air chamber, a hollow cylinder, a drummer located in it, dividing the cylinder cavity into the idle and working chamber mounted on one end of the cylinder from the side of the working chamber, a cover with a shoulder, a tube with a constantly open inlet channel connecting the pre-chamber to the idle chamber, a glass with face flange facing the collar of the lid, an annular non-flow afterburner chamber located in the cylinder wall from the idle chamber side, an afterburner channel periodically reporting a non-flow afterburner chamber with an idle chamber, made in the cylinder wall in the form of a radial channel, exhaust channels made in the side wall of the cylinder, and a working tool with a shank, and the hammer is made with internal and external chambers, recesses, communicated constantly with each other through the bypass channel and so that e, from the cut-off edge of the cut-off of the afterburner channel to the exhaust channel, the outer recess chamber on the striker is made large, and a radial channel is made on the side surface of the tube, periodically communicating the inner recess chamber in the striker with the longitudinal tube channel, and the longitudinal channel of the tube from the tool side is provided with a channel -throttle trigger.

The drawing shows a pneumatic impact device with a partial longitudinal section with a non-flow afterburner chamber.

Pneumatic shock device with throttle air distribution (see drawing) contains a hollow cylinder 1 with a drummer 2 located in it, dividing the cylinder cavity into the chambers of the working 3 and idle 4 strokes. In the drummer 2, an inner 5 and an outer 6 of the undercut chamber are interconnected by a bypass channel 7. On the side of the chamber 3, the cylinder is covered by a lid 8 with a central hole 9 for passing a tube 10 with a throttle channel 11 equipped with a launch choke 12 to the chamber 4 and a radial channel 13 for periodic communication with the undercut chamber 5. The cover 8 is provided with a flange shoulder 14 and a sealing shoulder 15, by means of which it rests on the end face 16 of the cylinder 1 and the cup 17, which is equipped with an annular step shoulder 18 facing bead 15. Cover 8 is also provided with an annular throttle 19 of the inlet into the chamber 3, formed by the side surfaces of the hole 9 and the tube 10 in the form of a gap. The cup 17 is sealed and detachable, for example, by means of a threaded connection, mounted on the cylinder 1 and provided with a channel 20 that constantly communicates the network air chamber 21 formed by the end face of any known type of air distribution device 22 with the cup 17 detachably interconnected. The lid 8 with the end face of the cup 17 from the shoulder 18 forms a pre-chamber 23, constantly connected by the channel 20 to the network air chamber 21, connected by the channel 24 to the compressed air network by means of an air distribution device 22. The inner side surface of the glass 17 and the outer side surface of the cylinder 1 form an accumulation chamber 25, constantly in communication with the chamber 3 by means of a radial bypass channel 26. The cylinder 1 is provided on the side of the chamber 4 with an annular non-flowing afterburner chamber 27, periodically communicating via the shaft of the afterburner radial channel 28 in the cylinder with the chamber 4. A radial exhaust channel 29, at the level of which an air baffle ring 30 with an exhaust channel is installed, for example, in the form of a slit 31. An exhaust chamber 32 is formed between the ring 30 and the cylinder 1. Shank 33 of the working tool 34 installed in the cylinder from the side of the chamber 4 and is prevented from falling out by the device for holding it, for example, in the form of a rubberized metal cap 35, which is detachably fixed relative to the cylinder by means of a threaded or other known connection I am.

Pneumatic shock device with throttle air distribution works as follows.

When the supply device 22 is turned on, compressed air enters through the channel 24 into the network air chamber 21, from where through the channel 20 to the pre-chamber 23 and then the main air enters the working chamber 3 through the annular throttle channel 19. At the same time, the main air enters the chamber 4 from the pre-chamber 23 idling through the throttle channel 11 in the tube 10 through the start-throttle channel 12, and also into the non-flow afterburner chamber 27 through the flow system of channels: the longitudinal channel 11 and the radial channel 13 in the tube 10, the inner annular chamber-recess 5 of the hammer , a bypass channel 7, an external annular chamber-recess 6 of the striker and a radial channel 28. Thanks to the marked flow system, the non-flowing afterburner chamber 27 is filled with air with a pressure close to the network pressure.

As the striker 2 moves, the radial channel 28 is closed, maintaining the air pressure equal to the network pressure in the afterburner chamber 27.

With further movement of the hammer 2, the pressure in the idle chamber 4 will decrease. This is due to the rapidly increasing volume of the chamber 4 during idle and it does not have time to fill up with the network air coming from the chamber 24 through the start-throttle channel 12 in the tube 10, and when the radial channel 13 is opened, the chamber 4 will be filled with air more intensively, which will increase the pressure pulse in her.

With further movement of the striker 2, its lateral surface will open the afterburner channel 28 and the air accumulated in the non-flowing afterburner chamber 27 will sharply fill the volume of the chamber 4, which will significantly increase the idle air pressure pulse and the velocity of the striker.

With further movement of the striker 2, its lateral surface will open the exhaust channel 29. Since the exhaust air is discharged from the chamber 4 through the exhaust channel of a certain passage section, a sharp decrease in air pressure in the chambers 4 and 27 will not occur, and the pressure in the chamber 4 will be maintained calculated.

Simultaneously, in the chamber 3 of the working stroke and the chamber 25 communicated with it through the channel 26, the process of compression of the air cut off in them and the network air again coming from the chamber 23 through the annular throttle inlet channel 19 will begin.

After the lateral surface of the striker 2 of the exhaust channel 29 is opened and its subsequent movement is in progress, the air pressure in the idle chamber 4 and the afterburner inertia chamber 27 connected with it smoothly, due to the intake of air from the chamber 23 through the ducts 11, 13 and 12, decreases to atmospheric. Under the influence of the difference of pulses of air pressure in the chambers 3 and 4, the firing pin 2 will slow down its movement. Moving under the influence of a pulse, the air pressure from the side of the chamber 4 and overcoming some back pressure from the side of the chamber 3, the hammer continues to compress the air in the chamber 3 and the chamber 25 communicated through the channel 26, including the air coming from the chamber 23 through the annular channel 19. After overlapping channel 26 firing pin 2 and when aligning the power pulses acting on the firing pin from the side of chambers 3 and 4, it will stop at the calculated point. Immediately under the influence of an air pressure impulse from the side of the chamber 3, the hammer will begin to accelerate toward the shank 33, making a working stroke. The drummer 2 opens the channel 26 and the chambers 3 and 25 communicate with each other and the air pressures in them are equalized, while at the end of the idle and the beginning of the working stroke of the hammer the pressure in the chambers 4 and 27 will remain almost equal to atmospheric, since the exhaust channel 29 has a passage area sections significantly exceeding the area of the channel-inductor 12 of the launch and the radial channel 13 in the tube 10.

During subsequent movement, the hammer 2 will block the outlet channel 29 with its lateral surface, as a result of which the pressure of the air cut off in the chamber 4 and 27, as well as the air flowing back into these chambers through the launch choke 12 and the radial channel 13 to the tube 10 will begin to increase. After the drummer blocks 2 channels 13 and 28, air will enter the chamber 4 only through the channel throttle 12, without creating from the side of the chamber 4 significant backpressure and braking forces of the striker.

As you move the firing pin 2 will block the channel 28 and disconnect the chambers 4 and 27, then open the flow system of channels: the radial channel 13 in the tube 10, the inner annular chamber-recess 5 of the striker, the bypass channel 7, the outer annular chamber-recess 6, radial channel 28 afterburner. Thanks to the flow system of the channels, the non-flowing afterburner chamber 27 will be filled with air by entering it through the channel 11 of the tube 10 to a pressure close to its pressure in the chamber 23. After the drummer opens the channel 2, the air pressure in the working chamber 3 and the chamber 25 connected to it through the channel 26 will decrease to atmospheric pressure, despite the flow of air through the annular throttle channel 19 of the inlet from the chamber 23, since the passage section of the exhaust channel 29 is much larger than the cross section of the channel 19. Thus, the exhaust air from the chambers 3 and 25 is discharged through the channel 29 into the exhaust chamber 32 and through the slotted channel 31 in the air exhaust ring 30 to the atmosphere.

Under the influence of the difference of pressure pulses in chambers 3 and 4, the striker 2, overcoming the counterpressure from the side of the chamber 4, strikes the shank 33 of the tool 34 and the described working process will be repeated with the only difference that the subsequent idle stroke of the striker will also be formed with the participation of the rebound pulse drummer from the tool shank.

Performing the height of the external chamber-recess 6 of a shorter distance from the cut-off edge of the cut-out of the afterburner channel 28 to the exhaust channel 29 and performing the throttle inlet channel 7 calibrated allows the calculated air pressure in the non-flow chamber 27 of the afterburner when the hammer 2 is in the chamber 4 between the shank 33 and the outlet 29, and when the chamber 4 communicates with the atmosphere through channel 29, the air flow through channels 12 and 13 will not exceed the calculated one. The above allows, without increasing the total air flow, through the implementation of afterburner at idle from the side of the chamber 4, in conjunction with the placement of the afterburner channel 28 in relation to the exhaust channel 29 in the cylinder wall 1 in a section no longer than the length of the hammer 2, reduce backpressure in the chamber 4 by reducing the flow area of the channel 12 in the tube 10.

Reducing the back pressure in the chamber 4 will allow to increase the length of the acceleration section during idling without increasing the idle time due to the afterburner pulse, and during the working stroke in the same phase of acceleration of the striker due to the reduction of back pressure from the side of the camera 4, also reduce the cycle time than increase the frequency impacts of a pneumatic impact device with throttle air distribution, and with sufficient energy of a single impact, increase the efficiency of impact on the medium being treated.

Claims (1)

Pneumatic shock device with throttle air distribution, including a network air chamber, a pre-chamber, a device for switching on compressed air to the network air chamber, a hollow cylinder, a shock placed therein, dividing the cylinder cavity into the idle and working chamber mounted on one end of the cylinder from the side travel chamber lid with collar, tube with a constantly open inlet channel connecting the pre-chamber to the idle chamber, a glass with an annular collar facing the collar cover lid, an annular non-flowing afterburner chamber located in the cylinder wall from the idle chamber side, an afterburner channel periodically communicating a non-flowing afterburner chamber with the idle chamber, made in the cylinder wall in the form of a radial channel, exhaust channels made in the side wall of the cylinder, and a working tool with a shank, characterized in that the hammer is made with internal and external chambers, recesses, constantly communicated with each other through the bypass channel, and the distance from the cut edge of the slice channel afterburner to the outlet channel formed larger length of the outer chamber, the undercut on the striker, and on the lateral surface of the tube is formed radial passage intermittently communicating an interior chamber, the recess in the striker with the longitudinal bore of the tube and a longitudinal tube channel from the tool is provided with a duct-throttle start.