RU2773755C1 - Pneumatic hammer - Google Patents

Abstract

FIELD: mechanical engineering.

SUBSTANCE: invention relates to pneumatic impact machines and can be used in construction, mining and mechanical engineering. The pneumatic hammer contains a cylindrical body, a working tool held by a latch relative to the cylindrical body, a handle with an intake device, a partition with an intake throttle, an outlet channel and an axial hole in which a tube with a longitudinal outlet channel and a radial outlet channel extending into its side surface is installed and fixed, an annular exhaust chamber with an outlet channel formed by a partition, a cylindrical body and a handle body, a pre-chamber formed by a handle body and a partition, having the possibility of communication by means of an inlet channel with a compressed air network, a striker with a through axial channel for passing the said tube, dividing the cavity of the cylindrical body into a working stroke chamber located on the side of the partition, which has the possibility of constant communication with the pre-chamber by means of an inlet throttle in the partition, and an idle chamber located on the side of the working tool, which has the possibility of periodic communication by means of radial and longitudinal outlet channels in the tube and an outlet channel in the partition, with an outlet to the annular exhaust chamber and by means of an outlet channel in the handle housing with an atmospheric chamber formed by the handle housing and an air intake ring, while a recess is made in the cylindrical housing from the side of the idling chamber, and a bypass channel made with the possibility of communicating the working and idling chambers with each other, in this case, the bypass channel is made on the side surface of the tube in the form of a drainage screw channel-groove with a constant depth and cross-sectional area in the form of a rectangle or square with the formation of collars and grooves and with the possibility of communicating the working and idling chambers with each other, and so that the radial outlet channel in the tube is made in the collar without the possibility of its communication with grooves in the position of the striker leaning on the working tool.

EFFECT: increase in the energy and frequency of impact, as well as, due to the exclusion of channels on the side surface of the striker, an increase in its strength and the service life of the hammer as a whole.

1 cl, 1 dwg

Description

The invention relates to the field of construction, in particular pneumatic impact machines, and can be used in the destruction of hard materials, and can also be used in mining and mechanical engineering.

Known pneumatic hammer (RF patent No. 2583575, 2016 B25D 9/04, B25D 9/08) containing:

- cylindrical body;

- a working tool held by a latch relative to the cylindrical body; handle with inlet device;

- a partition with an inlet throttle channel and an axial hole in which a tube is installed and fixed, with a longitudinal outlet channel; a radial outlet channel extending in its side surface;

- an annular outlet chamber, with an outlet formed by a baffle, a cylindrical body and a handle body;

- an antechamber formed by the body of the handle and a partition, communicated by means of an air supply channel, with a network of compressed air;

- a striker with a through axial channel, for passing the said tube, dividing the cavity of the cylindrical body into the working stroke chamber, from the side of the partition, constantly communicating with the flow chamber, by means of an inlet throttle in the partition;

- an idle chamber on the side of the working tool periodically communicated by means of radial and longitudinal outlet channels in the tube;

- an outlet channel made in the partition with access to the annular outlet chamber and through the outlet hole in the handle body into the atmospheric chamber formed by the handle body and the air baffle ring in a cylindrical body;

- a groove in the housing from the side of the idle chamber;

- a bypass channel on the side surface of the striker, in the form of an inclined groove at an angle to the generating surface of the striker with a permanently open outlet at the end of the striker from the side of the working stroke chamber.

The disadvantage of the described design is:

Significant air counterpressure from the side of the working stroke chamber at the end of idling due to air compression by the moving drummer, which is enhanced by the constant intake of mains air from the prechamber through the throttle channel in the partition, as a result of which the drummer starts braking prematurely and does not reach the calculated stroke value; significant air counterpressure in the idle chamber at the end of the working stroke before the striker collides with the tool shank, due to the compression of the air cut off in the chamber and the air entering through the bypass channel made on the side surface of the striker when its radial channel exits into the annular groove of the idle chamber with a sharp bypass into its volume of air from the working stroke chamber, as a result of which the striker brakes prematurely with a loss of impact speed, and consequently a loss of energy of the shock pulse transmitted to the tool shank.

The closest in technical essence, the claimed device, selected as a prototype, is a pneumatic hammer (RF patent No. 2728059, 2020 B25D 9/04, B25D 9/20, B25D 17/02, E21C3 37/24), containing a cylindrical body , a working tool held by a lock relative to the cylindrical body, a handle with an inlet device, a partition with an inlet throttle, an outlet channel and an axial hole in which a tube with a longitudinal outlet channel and a radial outlet channel extending into its side surface is installed and fixed, an annular outlet chamber with an outlet formed by a partition, a cylindrical body and a handle body, an antechamber formed by a handle body and a partition and communicated through an air supply channel with a compressed air network, a striker with a through axial channel for passing said tube, dividing the cavity of the cylindrical body into the working stroke chamber from the side of the partition , constantly informed yu with the pre-chamber by means of an inlet throttle in the partition and an idle chamber on the side of the working tool, periodically communicated by means of radial and longitudinal outlet channels in the tube and the outlet channel in the partition with access to the annular outlet chamber and through the outlet hole in the handle body to the atmospheric chamber formed the handle body and the air baffle ring, in the cylindrical body on the side of the idle chamber, a groove is made, and on the side surface of the drummer there is a bypass channel in the form of a screw groove, with constantly open exits to the idle chamber and the working stroke chamber with constant communication of both chambers with each other and so that the open outlet of the through helical channel is made with a decreasing cross-sectional area towards the idle chamber.

The disadvantage of the prototype are:

the presence of a significant number of areas of stress concentration along all turns of the helical channel-groove, which reduces the strength of the striker during collisions with the shank of the working tool; the increase in the strength of the striker determines the increase in its diametrical cross-sectional area due to the placement of the channel-groove on its side surface; the channel-groove is made with a varying depth and a decreasing cross-sectional area, which changes the position of the center of gravity along the longitudinal axis, which reduces the stability of the impactor in the channel of the cylindrical body and creates different loads in the protrusions of the channel-groove during impact with the shank of the working tool, which leads to a violation of the equal strength of the annular part of the impactor.

The objective of the claimed invention is to exclude the load from stress concentrators on the side boundaries of the bypass channel-slot, increase the strength properties of the impactor by eliminating the channel-slots on the side surface of the impactor, maintain the drainage properties of the bypass channel-slots that perform the function of a drainage channel between the chambers of the working and idling strokes, providing reduction of counterpressure from the side of the working stroke chamber during the idling of the striker, which eliminates premature braking of the striker, therefore, the striker guarantees the achievement of the design stroke, and during the working stroke, the backpressure in the idle chamber is reduced, which helps to maintain the value of the pre-shock velocity of the striker, this allows you to increase energy hit.

The problem is solved by the fact that in a pneumatic hammer containing a cylindrical body, a working tool held by a latch relative to the cylindrical body, a handle with an inlet device, a partition with an inlet throttle, an outlet channel and an axial hole in which a tube with a longitudinal outlet channel and a radial outlet channel extending in its lateral surface, an annular outlet chamber with an outlet channel formed by a partition, a cylindrical body and a handle body, an antechamber formed by a handle body and a partition and communicated through an outlet channel with a compressed air network, a striker with a through axial channel for passing the mentioned a tube dividing the cavity of the cylindrical body into one located on the side of the partition of the chamber of the working stroke, having the ability to communicate with the pre-chamber by means of an inlet throttle in the partition and idling, located on the side of the working tool, having the possibility of periodic communication through radial and longitudinal outlet channels in the tube and the outlet channel in the partition with access to the annular outlet chamber and through the outlet channel in the handle body to the atmospheric chamber formed by the handle body and the air baffle ring, while in the cylindrical body from the side of the idle chamber a recess and a bypass channel are made, having the ability to communicate between the working and idle chambers, according to the invention, the bypass channel is made on the side surface of the tube in the form of a drainage screw channel-groove with a constant depth and cross-sectional area in the form of a rectangle or square with the formation of beads and grooves and with the possibility of providing communication between the working and idle chambers, and so that the radial outlet channel in the tube is made in a shoulder without the possibility of its communication with the grooves in the position of the striker supported on the working tool.

The drawing (Fig. 1) shows a longitudinal section of a pneumatic hammer with a drainage screw channel-groove on the side surface of the tube in the form of a rectangle or square in cross section with permanently open outlets to the working stroke chamber and the idle chamber with an annular recess.

The pneumatic hammer contains a cylindrical body 1 with a recess 2, a working tool 3 held by a latch 4 relative to the body 1, a partition 5 with an inlet throttle 6, an outlet channel 7, a tube 8 with a longitudinal outlet channel 9 and a side outlet channel 10, a radial outlet channel 11 on the side surface of the tube 8, the drummer 12, the idle chamber 13 with a recess 2 on the side of the working tool 3, the chamber 14 of the working stroke on the side of the partition 5, the drainage screw channel-groove 15 on the side surface of the tube 8 with a constant cross-sectional area and a groove depth in in the form of a rectangle or square, the radial channel 11 of the outlet in the tube 8 is made in the shoulder 16 of the turn without communication with the groove 17 of the screw channel-groove 15. The drummer 12 is provided with an axial through channel 18 for passing the tube 8. The handle 19 through a threaded connection on its body 20 and cylindrical body 1 tightly presses the partition 5 to the end of the cylindrical body 1 from the side of the chamber 14 of the working move. The body 20 of the handle 19 includes an outlet channel 21, an inlet channel 22 and a network air pre-chamber 23 formed between the body 20 and the partition 5. with an atmospheric chamber 25 formed by a body 20 and a detachable air baffle ring 26 installed with it. The body 20 of the handle 19 is fixed relative to the cylindrical body by a latch 27 and a retained annular casing 28.

Pneumatic hammer works as follows.

After turning on the mains air supply device (not shown in the drawing (Fig. 1) and can be any known by design solution), air enters through the inlet channel 22 of the handle 19 into the pre-chamber 23 of the mains air, from where through the inlet throttle 6 in the partition 5 into the chamber 14 working stroke.

In the position of the pneumatic hammer shown in (Fig. 1), air from the chamber 14 of the working stroke through the drainage screw channel-groove 15 of the tube 8 and further along the side surface of the drummer 12 enters the idle chamber 13 with a recess 2 in the cylindrical body 1. between themselves, the idle chamber 13 and the working stroke chamber 14 change the functions of the chambers: the working stroke chamber 14 acquires the functions of a chamber with partial air displacement, the idle chamber 13 acquires the functions of a flow-through pressurization chamber.

As a result of the above, in the chamber 14 of the working stroke, the air pressure at the intake through the intake throttle channel 6 from the prechamber 23 rises slowly, and the air pressure in the idle chamber 13 will be maintained higher due to its leakage from the chamber 14 of the working stroke. Under the action of air pressure on the end face of the drummer 12 from the side of the idle chamber 13, the drummer moves towards the chamber 14 of the working stroke, making an idle stroke.

In the idle chamber 13, the process of air expansion continues while it is simultaneously bypassed from the chamber 14 of the working stroke, in which the compression process continues, the air remaining in it and the air that continues to flow through the inlet throttle 6 of the partition 5 from the prechamber 23.

Continuing the movement of the drummer 12 with its end from the idle chamber 13 will open the radial outlet channel 11 and through the longitudinal outlet channel 9, as well as the side outlet channel 10 of the tube 8 and the outlet channel 7 in the partition 5, the outlet annular chamber 24 of the outlet channel 21 in the housing 20 handle 19 and the atmospheric chamber 25 formed by the housing 20 and the air baffle ring 26, the air from the idle chamber 13 will be released into the atmosphere and the air pressure in the idle chamber 13 is equalized to atmospheric pressure.

Continuing to move, the drummer 12 under the action of inertia forces overcomes the air resistance from the side of the chamber 14 of the working stroke, slows down and stops in the calculated position.

After stopping, the drummer 12, under the action of air pressure from the side of the chamber 14 of the working stroke, will begin an accelerated movement towards the chamber 13 of the idle stroke, making the working stroke.

With the increasing volume of the chamber 14 of the working stroke with the simultaneous flow of air through the inlet throttle 6 of the partition 5 from the pre-chamber 23, the air in the chamber 14 of the working stroke will expand rapidly.

Continuing to move, the striker 12 of the pre-chamber will block the radial outlet channel 11 of the tube 8, after which the idle chamber 13 will be separated from the atmosphere and the process of compressing the air cut off in it and the air flowing from the chamber 14 of the working stroke through the drainage screw channel-groove 15 of the tube 8 and further along the side surface of the drummer 12 into the idle chamber 13.

As a result of such air distribution in the volume of the idle chamber 13 and the volume of the undercut 2, the process of compressing the air cut off in them and the air coming from the working stroke chamber 14 with less air counterpressure from the side of the idle chamber 13 will continue.

With the subsequent movement of the drummer 12, the air pressure due to the volume of the groove 2 from the side of the chamber 13 of the idle stroke will not significantly affect the growth of the counterpressure and premature braking of the drummer 12, but will significantly increase the air pressure pulse from the side of the chamber 13 of the idle stroke at the beginning of the idle stroke of the drummer 12, which will provide due to its greater speed when colliding with the shank 3 of the working tool, the corresponding values of the energy parameters of the working process. After the collision, the working process of the pneumatic hammer will be repeated and the next idle stroke of the striker 12 is carried out due to the air pressure pulse from the idle chamber 13 and the addition of the rebound pulse of the striker 12 from the working tool 3.

The use of the claimed invention allows for constant air drainage between the working and idling chambers with a lower air counterpressure in them, due to which, at the end of the stroke of the striker, partial displacement of air from the idle chamber during the pre-shock period into the working stroke chamber is ensured, which allows to increase the speed of the striker when colliding with a working tool and increase the impact energy. When the striker is idling, the drainage displacement of air from the working stroke chamber causes a decrease in the air counterpressure from its side and prevents premature braking of the striker, which ensures the guaranteed value of the design stroke of the striker. Thus, the proposed technical solution for the working process of a pneumatic hammer using a drainage screw channel-groove, on the side surface of a tube with a constant depth and cross-sectional area in the form of a rectangle or square with the formation of flanges and grooves with constant communication between the working and idling chambers and so that the radial outlet channel in the tube 8 is made in the shoulder 16 without communicating it with the grooves 17 in the position of the striker resting on the working tool 3 allows you to increase the impact energy transmitted to the working tool, and also, by eliminating the channels on the side surface of the striker, increase it strength and resource of the hammer as a whole. Additional positive features of the proposed technical solution are in the constructive solution of the drainage screw channel-groove 15, which provides cooling of the striker 12 with air flow during its working and idling.

Claims (1)

Pneumatic hammer containing a cylindrical body, a working tool held by a latch relative to the cylindrical body, a handle with an inlet device, a baffle with an inlet throttle, an outlet channel and an axial hole in which a tube with a longitudinal outlet channel and a radial outlet channel extending into it is installed and fixed. side surface, an annular outlet chamber with an outlet channel formed by a baffle, a cylindrical body and a handle body, an anterior chamber formed by a handle body and a baffle that can communicate with the compressed air network through an inlet channel, a striker with a through axial channel for passing the said tube, dividing the cavity cylindrical body on the working stroke chamber located on the side of the partition, having the possibility of constant communication with the pre-chamber by means of an inlet throttle in the partition, and the idle chamber located on the side of the working tool, having the possibility the importance of periodic communication through radial and longitudinal outlet channels in the tube and the outlet channel in the baffle, with access to the annular outlet chamber and through the outlet channel in the handle body with an atmospheric chamber formed by the handle body and the air baffle ring, while in the cylindrical body on the side of the idle chamber groove is made, and the bypass channel is made with the possibility of providing communication between the working and idle chambers, characterized in that the bypass channel is made on the side surface of the tube in the form of a drainage screw channel-slot with a constant depth and cross-sectional area in the form of a rectangle or square with the formation of shoulders and grooves and with the possibility of providing communication between the working and idling chambers, and so that the radial outlet channel in the tube is made in the shoulder without the possibility of its communication with the grooves in the position of the striker supported on the working tool.

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