RU2191105C1 - Pneumatic hammer with throttle air distribution - Google Patents

Abstract

FIELD: construction industry. SUBSTANCE: pneumatic hammer has hollow cylinder, sleeve equipped with air channel and fixed on cylinder, air baffle-type ring, and striker. Striker with central channel divides cylinder cavity into idle stroke chamber and working stroke chamber. Air is supplied through main chamber. Cylinder is provided with cover positioned at side adjoining working strike chamber and provided with central through opening. Movable pipe is extending through cover opening and striker central channel to connect main chamber with idle stroke chamber. Pipe and central through opening side walls define throttle channel connecting main chamber to working stroke chamber. Pipe is equipped with step positioned at the level of cover opening and provided with channel formed in its side surface and adapted for periodical air bypassing. In the process of completion of idle stroke by striker, channel is opened to provide for supplying of additional air into working stroke chamber. Pneumatic hammer of such construction may be used for crushing rock and frozen ground. EFFECT: increased efficiency by increased frequency and power of stroke. 9 cl, 8 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 percussion machines for the destruction of rock and frozen soils.

 A pneumatic hammer is known (see, for example, AS SU 1061982, Mcl B 25 D 8/04, 1983), including a cylindrical body, a drummer placed in it with a through axial hole, dividing the body cavity into the working chamber and idle, a cover with an axial multichannel tube, which serves for the intake of compressed air into the chambers, and a system of exhaust chokes periodically communicating the chambers with the atmosphere, the system of exhaust chokes made in the cover and the tube, which is rigidly and tightly fixed relative to the cover and the side surface in interacts with the surface of the through hole in the hammer.

 The disadvantage of this and similar pneumatic hammers is the compulsory sealed fixed tube seating relative to the lid or cylindrical body, as well as movable drummer landings relative to the tube and cylindrical body.

 Also known is a pneumatic hammer (see, for example, AS su 1235719, M. class B 25 D 9/04, 1986), comprising a housing with accumulation chambers and exhaust channels, connected to it by a foot with a preliminary chamber, placed in the housing is aligned with the air supply tube fixed in the foot, and the hollow hammer interacting with the tube, periodically blocking the exhaust channels and forming working and idle chambers with the housing, periodically communicated to each other via bypass channels and constantly from the preliminary chambers second means inlet throttle and the working tool, wherein an intake throttle, which connects the idling pre-chamber chamber formed in the tube in the area of its fastening to Fittings and passageways are formed as longitudinal grooves in the outer cylindrical surface of the tube periodically overlapped ends of the striker.

 The main disadvantage of this and similar pneumatic hammers is the compulsory compaction of a fixed tube fit in the foot (cover), as a pinch-pin with a console supported on a movable part with a fit in a through axial hole of a hollow hammer. With such and similar fastenings of the tube, it is also necessary to provide a sealed landing of the striker relative to the tube and the cylinder of the body. The inability to process the axial holes of the cylinder, impactor, tube and cover from the "one installation" causes misalignment of the holes and leads to distortions, "biting", increased uneven friction on the mating interacting surfaces and braking of the impactor and, as a result, lowering the energy of a single impact and the number of strokes as well as breaking the tube and stopping the hammer. Distortions lead to involuntary leaks and overflows that violate the calculation process in the working chambers of the hammer.

 The closest technical solution is a pneumatic hammer with throttle air distribution (see, for example, patent RU 2062692, Mcl B 25 D 3/4, E 21 C 3/24, 1996), including a network camera, a handle with a feed switch compressed air into the network chamber, a hollow cylinder, the drummer located in it with the central channel and dividing the cylinder cavity into the idle and working chamber, a movable tube passed through the central channel of the drummer connecting the network chamber with the idle chamber through a constantly open inlet throttle channel, a cover with a shoulder and a central through hole for passing a tube through it at one end of the cylinder on the side of the working chamber chamber; a throttle channel constantly connecting the inlet chamber to the working chamber connecting the network camera with the working chamber communicated with the last accumulation chamber bypass channels, exhaust channels made in the side wall of the cylinder, and a working tool with a shank installed in the other end of the cylinder, and on the flange of the cover the cup is surrounded by its bottom, the annular accumulation chamber is formed by the cup wall and the outer lateral surface of the cylinder, the bypass channels are made in the cylinder wall at the level of the working chamber in the form of radial channels, the movable tube is made with the possibility of axial and radial movement relative to the central through hole of the lid, and the throttle channel open inlet to the working chamber is made in the form of an annular channel with the possibility of changing the shape of its cross section, formed side of the tube and the central through hole in the cover.

 The specified device, as containing the largest number of essential features in relation to the proposed, adopted as a prototype.

 The disadvantage of the prototype is the impossibility of sharper braking of the drummer at the end of idle and its earlier and more intense acceleration at the beginning of the working stroke.

 This drawback can be eliminated, for example, by additional supply of compressed air to the working chamber at the end of the idle and the beginning of the working stroke of the hammer, thereby performing a buffer cycle. The implementation of such a cycle will increase both the frequency of impacts by reducing the time of idle and working stroke, and the energy of the impact due to greater acceleration of the striker at the beginning of the working stroke and its greater speed at the end of the working stroke, that is, by increasing the speed of impact of the striker with the tool.

 The essence of the proposed technical solution for a pneumatic hammer is as follows.

 An air hammer with a throttle air distribution includes a network camera, a handle with a device for switching compressed air into the network camera, a hollow cylinder, a drummer with a central channel placed in it and dividing the cylinder cavity into idle and working chambers, a movable tube passed through the central channel of the drummer connecting a network camera with an idle camera through a constantly open inlet throttle channel mounted on one end of the cylinder from the side of the working chamber, a cover with a throttle and a central through hole for conducting a tube through it, a throttle channel that constantly connects the inlet into the working chamber connecting the network camera with the working chamber, connected to the latter by the accumulation chamber bypass channels, exhaust channels made in the side wall of the cylinder, and a working tool with a shank installed in the other end of the cylinder, a beaker is mounted on its flange on the flange of the lid; the annular accumulation chamber is formed by the wall of the beaker and the outer side the top of the cylinder, the bypass channels are made in the cylinder wall at the level of the working chamber in the form of radial channels, the movable tube is provided with a restrictive collar and is made with the possibility of axial and radial movement relative to the central through hole of the cover, and the throttle channel is constantly open to the inlet into the working chamber in the form of an annular channel with the possibility of changing the shape of its cross section with a constant area formed by the side surfaces of the tube and the central kvoznogo holes in the cover, the tube from the limiting collar at the central hole cover is provided with a step with periodic bypass channel at its side surface for air bypass air network between the cameras and stroke.

 It is advisable to channel periodic bypass to perform in the form of an open groove with cut off along the length of the edges.

 It is advisable to carry out the periodic bypass channel in the form of a circular channel in the stage body with cut-off edges along the length.

 It is advisable that the periodic bypass channel be made in the form of an open flat with cutting edges along the length.

 It is advisable to channel periodic bypass in the form of a circular channel in the body of the stage with a cutting edge from the side of the restrictive collar of the tube.

 It is advisable that the periodic bypass channel be made in the form of an open groove with a cutting edge from the side of the tube collar.

 It is advisable that the periodic bypass channel be made in the form of a flat with a cutting edge from the side of the tube collar.

 It is advisable to channel periodic bypass in the form of a helical channel with cut off along the length of the edges.

 It is advisable to channel periodic bypass in the form of a helical channel with a cutting edge on the side of the limiting flange of the tube.

 The implementation of the proposed technical solution of the hammer is illustrated by drawings, in which Fig. 1 shows a hammer with a partial cross-section with a bypass channel in the form of an open groove in the body of the tube stage with cut-off edges along the length; figure 2 and 3 are fragments of the execution of the bypass channel in the form of a round channel and flats with a cutting edge from the side of the limiting flange of the tube and stage; figure 4-7 - fragments of the execution of the bypass channel in the body of the stage in the form of a circular channel, an open groove, flats and an open screw channel with cutting edges on the side of the restrictive collar of the tube.

 Designations on all figures are accepted the same.

 Pneumatic hammer with throttle air distribution (see figure 1) contains a hollow cylinder 1 with a drummer 2 placed in it with a central through channel 3, dividing the cavity of the cylinder 1 into the chamber of the working 4 and idle 5 strokes and the tube 6, which interacts with the central channel 3 drummer 2 and is equipped with a constantly open longitudinal throttle channel 7 in the idle chamber 5, a throttle annular channel 8 for the continuous supply of network air to the working chamber 4. The pipe 6 is installed on the side of the working chamber 4 in the price the swivel hole 9 of the fixed cover 10 and is equipped with a restrictive flange 11 with the transition to the stage 12 with the annular platform 13 facing the drummer 2, which is the anvil for the hammer 2 when they collide.

 The possibility of longitudinal and transverse movement of the stage 12 of the tube 6 is provided due to the absence of a rigid connection between the stage and the side surface of the Central hole 9 of the cover. Thus, the throttle annular channel 8 is formed by the gap between the side surfaces of the stage 12 and the hole 9.

 Step 12 is provided with a periodic bypass channel, for example, in the form of an open groove 14 with cutting edges 15 and 16 along the length of the generating step.

 The lid 10 is equipped with a flange collar 17 and a sealing collar 18, by means of which it rests on the end face of the cylinder 1 and the cup 19. The glass 19 is sealed and detachable, for example by means of a threaded connection, mounted on the cylinder and provided with an air supply channel 20 from the removable handle 21 with a starting device of any type. A network camera 22 is formed between the glass 19 and the flange 18 of the lid 10, and an annular accumulation chamber 23 is formed between the glass 19 and the cylinder 1, which is constantly in communication with the camera 4 by means of radial bypass channels 24 in the cylinder. The cylinder is equipped with radial outlet channels 25 and 26, arranged in tiers, at the level of which an air baffle ring 27 is installed on the cylinder with an outlet channel, for example, in the form of a slot 28. An outlet chamber 29 is formed between the ring 2 and cylinder 1. The tool tool shank 30 is installed in the chamber idle and is kept from falling out by the device, for example, in the form of a rubberized metal cap 31, which is fixed detachably relative to the cylinder by means of a threaded connection.

 The bypass channel in the stage 12 can be structurally made in the form of a circular channel 32 with the length 33 and 34 cut off along the lengths (FIG. 2), or in the form of an open flange 35 with the 36 and 37 cut off along the lengths (FIG. 3), or in the form of a round channel 38 with a cutting edge 39 from the side of the restrictive flange 11 (Fig. 4), or in the form of an open groove 40 with a cutting edge 41 from the side of the flange 11 (Fig. 5), or in the form of a flat 42 with a cutting edge 43 from the side flange 11 (Fig.6), either in the form of a helical channel 44 with cutting edges 45 and 46 (Fig.7), or in the form of a helical channel 47 with cutting edge 48 from the flange 11 (Fig. 8).

 A pneumatic hammer with throttle air distribution works as follows. When the handle 21 is pressed until the hammer tool stops in the medium to be processed and the trigger is pulled, the compressed air enters through the channel 20 in the glass 19 into the network air chamber 22. From the chamber 22, air enters the chamber 4 through the inlet throttle annular channel 8, formed by the lateral surfaces of the central hole 9 in the cover 10 and the stage 12 of the tube 6. From the chamber 4, the air through the bypass channels 24 in the wall of the cylinder 1 also enters the annular accumulation chamber 23. At the same time, the network air from the chamber 22 enters the idle chamber 5 through the inlet throttle channel 7 in the tube 6.

 The air pressure in the chamber 4 and 23 will remain almost equal to atmospheric, since the bypass channels 24 and the exhaust channel 26 in the cylinder 1 and the channel 28 in the ring 27 have passage areas that significantly exceed the area of the inlet throttle ring channel 8.

 In the idle chamber 5, the air pressure increases, since its volume is disconnected from the atmosphere, and the striker 2 begins to move along the tube 6 from the tool shank 30 installed in the cap 31, idling.

 When moving, the hammer 2 will block the main outlet channel 26 with its lateral surface, as a result of which the air pressure cut off in the chambers 4 and 23 will begin to increase. After the channel 26 is closed, the channel 25 will open and the air pressure in the idle chamber 5 will decrease to atmospheric pressure , despite the flow of air through the inlet channel 7 in the tube 6 from the chamber 22, since the flow area of the exhaust channel 25 is significantly larger than the flow area of the inlet throttle channel 7. This is reduced In addition, the opening exhaust channel 26 contributes to air pressure. Thus, the exhaust air from the chamber 5 is discharged into the exhaust chamber 29 and through the slotted channel 28 in the air baffle ring 27 to the atmosphere.

 As the drummer idles, the air pressure in the chamber 4 of the stroke and constantly communicated with the channels 24 accumulation chamber 23 will increase. With further movement of the drummer 2, two settings are possible. One of them provides with increasing air pressure on the annular platform 13 of the stage 12 and lower pressure on the flange 11 from the side of the chamber 22, the movement of the tube 6 with subsequent contact (collision) with the hammer and joint movement to a stop in the extreme calculated position. Another setting involves at a lower air pressure on the annular platform 13 of the stage 12 and more pressure on the flange 11 from the side of the chamber 22, impact of the hammer 2 with the annular platform 13 of stage 12 and the joint movement of the hammer and tube 6 to a stop in the extreme calculated position.

 When the tube 6 moves, the cutting edges 15 and 16 of the bypass channel in the form of a groove 14 in the stage 12 will open from the side of the central hole 9 and an additional portion of air from the network chamber 22 will immediately enter the working chamber 4 through the channel 14. In this regard, the pressure in the chamber of the stroke increases sharply. Under the influence of the difference of pulses of air pressure in the chambers 4, 23 and 5, the firing pin 2 will slow down its movement and stop at the calculated point.

 A similar process of pressurization of the chambers 4 and 23 by means of the bypass channel of the stage 12 of the tube 6 is carried out with other proposed structural solutions. So, when opening with respect to the Central hole 9 of the cutting edges 34 and 33 (Fig.2) of the bypass channel in the form of a channel 32 of circular cross section, a sharp inlet of the network air from the chamber 22 into the chamber 4 is carried out. Also, when opening with respect to the Central hole 9 of the cutting the edges 37 and 36 (Fig. 3) of the bypass channel in the form of a flat 35, the network air is sharply admitted from the chamber 22 to the chamber 4. Also, when opening with respect to the central hole 9 in the lid 10 of the cutting edge 39 of the bypass channel from the collar 11 of the tube 6 (figure 4) in the form of can Ala 38 of circular cross-section with direct access to the annular surface 13 of the stage 12, a sharp inlet of the network air from the chamber 22 into the chamber 4. A direct exit (cut) of the channel 38 causes less resistance at the outlet from it, and therefore, a higher efficiency of conservation of internal air energy to its expansion in the chamber 4. A similar process of pressurization with the conservation of internal air energy is carried out in the technical solution of the bypass channel, made in the form of a groove 40 (figure 5). So, when opening in relation to the Central hole 9 of the cutting edge 41 of the groove 40 from the side of the flange 11 is a sharp intake of air from the chamber 22 into the chamber 4.

 From the standpoint of cost-effectiveness of the energy carrier (compressed air) consumption, it is most preferable to make the bypass channel in the stage 12 in the form of a flat 42 (Fig.6), having minimal resistance to air movement over the entire length of the flat. So, when opening in relation to the Central hole 9 of the cutting edge 43 of the flats 42 from the side of the buric 11 is a sharp intake of air from the chamber 22 into the chamber 4.

 From the standpoint of economical consumption and reduction of the nomenclature of the cutting tool for manufacturing the bypass channel at the stage 12, it seems preferable to perform it in the form of a screw channel 44 with both two cutting edges 46 and 45 (Fig. 7), and a screw channel 47 with one cutting edge 48 ( Fig. 8).

 So, when opening with respect to the central hole 9 of the cutting edges 46 and 45 (Fig. 7) of the screw channel 44, the air inlet from the chamber 22 abruptly is introduced into the chamber 4. Also, when opening with respect to the central hole 9 of the cutting edge 48 of the screw channel 47 (Fig. 8) from the shoulder 11, a sharp inlet of the network air from the chamber 22 into the chamber 4 is carried out.

 After braking and stopping the hammer 2, it immediately under the influence of a pressure impulse from the side of chambers 4 and 23 will begin to accelerate toward the tool shaft 30, making a working stroke.

 As you move the firing pin 2, the air pressure in the chamber 4 of the stroke and constantly communicated with it channels 24 accumulation chamber 23 will decrease. This is because the rapidly increasing volume of the chamber 4 during the working stroke does not have time to fill up with the network air coming from the chamber 22 through the inlet throttle channel 8 and the additional bypass channel 14 in the stage 12 of the tube 6. There are two possible settings for the start of the movement of the hammer. One of them involves the movement of only the drummer 2 along the tube 6 — at a higher air pressure to the stage 13 of the stage 12 from the side of the chamber 4 and less pressure on the shoulder 11 from the side of the chamber 22, and then, when the air pressure decreases, the tube moves until it fits into the shoulder 11 on cover 10. Another setting involves the simultaneous movement of the striker 2 and the tube 6 — with less air pressure on the platform 13 of the stage 12 from the side of the chamber 4 and more pressure on the shoulder 11 from the side of the chamber 22, and then after the collar 11 is planted on the cover, the striker 2 is torn off from loschadki 13 and accelerated movement through the tube 6 only impactor.

 With further movement of the striker 2, its lateral surface will block the exhaust channel 25. At the same time, compression of the air cut off in it and the air of the network again coming from the chamber 22 via the inlet throttle channel 7 in the tube 6 will begin in the idle chamber 5 (Fig. 1). After the lateral surface of the striker 2 of the exhaust channel 26 opens, the air pressure in the working stroke chamber 4 and the accumulation chamber 23 communicated constantly with it will drop sharply to atmospheric pressure, since through the exhaust channel 24 the chamber 4 and the chamber 23 through the bypass channels 24, chamber 4 and channel 26 communicates with the exhaust chamber 29 and through the slot 28 in the air ring 27 with the atmosphere.

 Overcoming the impulse of counter-pressure of air from the side of the idle chamber 5 and under the influence of the difference of pulses of air pressure from the side of the chamber 4 and 5, the hammer 2 strikes the tool shaft 30 and the described hammer working process is repeated with the only difference that the hammer idle will also be formed with the participation of the rebound of the hammer 2 from the shank 30 of the tool.

 The stability of the launch, operation and reliability of the energy parameters of the hammer are realized if the tightness between the chambers 22 and 23, 22 and 4 is observed, which is caused by the flange collar 17 and the annular sealing collar 18, made on the annular sealing cover 10 and interacting directly with the glass 19.

 The presence of the flange 11 of the tube 6 prevents it from falling out through the central hole in the lid 10 or the channel 20 in the glass 19. In addition, the tube 6 by means of the flange 11 and its annular sealing seat rests on the annular sealing seat of the restrictive flange of the central hole 9 of the lid 10. This ensures uniform shock loading of the contact surfaces of the cover 10 and the collar 11 of the tube 6, thereby reducing specific loads and increasing the resource (durability) as landing contact surfaces her cap and collar pipe and a hammer as a whole.

 The proposed constructive solution ensures the constancy of the annular cross-section of the inlet throttle channel 8 into the chamber 4 of the working stroke, regardless of the position of the stage 12 of the movable tube 6 in the Central hole 9 of the fixed cover 10.

 In addition to the above, the implementation of the inlet throttle channel 7 into the idle chamber 5 in the tube 6 results in lower local path resistance and a higher efficiency of using the energy of compressed air consumed in the hammer working process.

Claims (9)

 1. A pneumatic hammer with throttle air distribution, including a network camera, a handle with a device for turning on the supply of compressed air to the network camera, a hollow cylinder, a drummer with a central channel placed in it and dividing the cylinder cavity into idle and working chambers, movable through the central channel of the drummer a tube connecting the network camera to the idle camera through a constantly open inlet throttle channel mounted on one end of the cylinder from the side of the roof working chamber with a shoulder and a central through hole for conducting a tube through it, a throttle channel connecting the network camera to the working chamber communicating with the latter through the bypass channels, exhaust channels made in the side wall of the cylinder, constantly open the inlet to the working chamber, and a working tool with a shank installed at the other end of the cylinder, while a cup is mounted on its flange on its flange, an annular accumulation chamber is formed by the wall of the cup and the outer the lateral surface of the cylinder, the bypass channels are made in the cylinder wall at the level of the working chamber in the form of radial channels, the movable tube is provided with a restrictive collar and is made with the possibility of axial and radial movement relative to the central through hole of the cover, and the throttle channel is constantly open to the inlet of the working chamber made in the form of an annular channel with the possibility of changing the shape of its cross section with a constant area formed by the side surfaces of the tube and a central through hole in the lid, characterized in that the tube on the side of the restrictive flange at the level of the central hole of the lid is equipped with a step with a periodic bypass channel on its side surface for periodically transferring air between the network air chambers and the working stroke.  2. A pneumatic hammer with a throttle air distribution according to claim 1, characterized in that the periodic bypass channel is made in the form of an open groove with edges cutting off along the length.  3. A pneumatic hammer with a throttle air distribution according to claim 1, characterized in that the periodic bypass channel is made in the form of a circular channel in the body of the stage with cut-off edges along the length.  4. A pneumatic hammer with a throttle air distribution according to claim 1, characterized in that the periodic bypass channel is made in the form of an open flat line with cut off edges along the length.  5. A pneumatic hammer with a throttle air distribution according to claim 1, characterized in that the periodic bypass channel is made in the form of a circular channel in the body of the stage with a cutting edge on the side of the restrictive collar of the tube.  6. A pneumatic hammer with a throttle air distribution according to claim 1, characterized in that the periodic bypass channel is made in the form of an open groove with a cutting edge on the side of the restrictive collar of the tube.  7. A pneumatic hammer with a throttle air distribution according to claim 1, characterized in that the periodic bypass channel is made in the form of a flat with a cutting edge on the side of the restrictive flange.  8. A pneumatic hammer with a throttle air distribution according to claim 1, characterized in that the periodic bypass channel is made in the form of a helical channel with cut-off edges along the length.  9. An air hammer with a throttle air distribution according to claim 1, characterized in that the periodic bypass channel is made in the form of a helical channel with a cutting edge on the side of the tube restriction flange.

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