SU207181A1 - PNEUMATIC SHOCK TOOL - Google Patents

Description

This invention relates to low impact pneumatic percussion instruments.

An ineutomic tool is known with a differential piston placed in a cylinder, having a groove in the middle part. The piston divides the cylinder into forward and reverse cavities and an intermediate cavity. The forward stroke cavity communicates with the air passage and the return cavity, and the intermediate cavity is connected to the exhaust port and has a chamber at the rear end that periodically communicates through the groove in the air port.

However, in this type of instruments there is not enough effective damping of recoil.

In the proposed tool, the middle part of the tool is made with a cross section decreasing to its shank.

With this design, recoil is effectively absorbed by smoothly increasing the air pressure in the chamber of the intermediate cavity at the end of the return and the beginning of the run due to the steadily increasing cross section of the groove and movement as it moves.

an intermediate zero of the cylinder of the proposed tool and a diagram of pressure change in the intermediate cavity of a zero-hole tool operating on a conventional cycle (dashed line), where 4 and / n is the return and forward stroke time, G is the cycle time; g - specific pressure; p is pressure;

(i) / 2 — excess (reactive) pressure pulses.

on fug. 26 is a diagram of pressure in the return cavity; on fug. 3 - pneumatic tool in another embodiment.

Pneumatic shock tool contains a stepped cylinder 1 (see Fig. 1), inside which is located the differential piston 2, the working tool 3 and the lid 4.

The piston 2 separates the cylinder / on the icing of the forward stroke A, the span between B and the reverse B. The chamber of the upper part of the intermediate cylinder is located at the top of the intermediate icing. The upper part of the piston 2 controls the compressed air inlet of the cylinders 1 and I and the lower part exhaust from these cavities. The middle part of the Porsch 2, which has a conical shape, forms at the inner surface of the rear stage of the cylinder / annular slit of variable cross section due to the groove when moving, the means of which automatically regulates the flow of supply air into the industrial cavity B. In the absence of compressed air in the tool piston 2 is located on the end of the working tool 3. At the same time, the cavities L and B of the cylinder and the channel D are interconnected and with the help of the channels and F with the air-supplying network.

The intermediate bed is through the window About communicated with the atmosphere. The tool works as follows. When the starter is opened, compressed air from the network through the channels and G through cavity A and channel D enters cavity B. Since the area of the piston head 2 is relatively small relative to the area of its shank, it will move upwards under the action of the pressure.

After the piston 2 blocks O (Fig. 2a, point c) in the intermediate cavity, free air will begin to compress, and since the top of the piston of channel D (Fig. 26, point d) is closed, network air will not enter the cavity B and it will net expansion process.

Continuing upward movement, the piston will open the window O (Fig. 26, point e), as a result of which exhaust from cavity B will occur. The pressure in it will fall sharply to atmospheric and piston 2 will continue to move upwards by inertia.

At some point (Fig. 2a, point e) the piston will open the channel W and the network air through the annular gap formed by its groove and the inner surface of the rear stage of the cylinder /, will flow into the ground; weft cavity B and chamber G.

Gradually decreasing as the Norsh 2 progresses upward the section of the annular gap and the corresponding volume of the chamber D causes a smooth increase in pressure in the intermediate cavity B at the end of the return stroke. As a result, when the piston 2 reaches the top position (Fig. 2a, point g), the pressure here will be significantly less than in hammers with a normal work cycle. Zan in the upper position, the piston 2 under the action of pressure from above and from the side of the chamber G will begin to move down, making a working stroke.

Due to the gradually increasing cross-section of the annular gap and the relatively slow movement of the piston in the initial period of the forward stroke, the pressure in the intermediate cavity B will gradually increase and a moment will come (Fig. 2a, point 3) when it reaches the maximum value close to the network one. In the future, as the speed of movement of the piston increases, the pressure in this space will gradually fall. Continuing the downward movement, the piston will close the channel F (Fig. 2a, point u). The supply of air into the intermediate cavity B will cease and a net expansion process will take place there. After the window O is closed (fig. 26, point k) and P1a2c compresses free air in cavity B, and from the moment of opening by the shank of piston 2 of channel D (fig. 26, point l) compressed air from the network will flow into this cavity.

After some time, the hole 2 will open the window O (Fig. 2a, point m), as a result of which the exhaust from the intermediate cavity B will occur and the pressure in it will fall sharply to atmospheric. Overcoming the resistance from below, the piston will strike the tool 3, and the above process will be repeated.

Due to the conical shape of the middle part of the piston and the presence of the chamber D, a significant decrease in the excess (reactive impulse (), a smooth increase and later on during the process of its impact on the tool body) is achieved. This causes a sharp decrease in the recoil amplitude and decrease in force on the tool.

In another embodiment, the impactor tool (see Fig. 3) has a stepped cylinder 1, inside of which is a differential piston 2 with an axial channel I, a working tool 3, a cover 4 and a fixed needle valve 5 at the rear of the cylinder.

The piston 2 separates the cylinder / into the cavities of forward stroke A, intermediate B and reverse B.

At the top of the intermediate cavity B is placed the camera -G. The upper part of the nozzle 2 controls the inlet of compressed air into the intermediate cavity B, and the lower part controls the exhaust from the cavities B and B of the cylinder /. Compressed air into cavity B flows through channel I in piston 2, and its flow is regulated by needle valve 5.

The working principle of this tool is somewhat different from the one described above.

In the absence of compressed air in the tool, the piston 2 is located below and rests on the end of the working tool 3. At this, the cylinder cavity A II B / through channel I, located in the body of piston 2, is interconnected and via channel E with an external network. Intermediate cavity B through the window Oh communicated with the atmosphere.

When the trigger is opened, the compressed nozzle from the network through channel E through cavity L and channel I in surface 2 enters cavity B. Under air pressure from the bottom, the piston will move upwards.

After the piston 2 overlaps the windows O (Fig. 2a, point c) in cavity B, free air will begin to compress, and from the moment the valve 5 is closed by channel I (Fig. 26, point d), the net air will not flow into the Viv cavity. extensions.

Its penetration will sharply drop to atmospheric, and the piston will continue to move all the way up by inertia. After some time (Fig. 2a, point e) it will open the access of the network air into the intermediate cavity B and the chamber through the segment slits formed by the Irodolic inclined flatheads 6 existing on its upper part (similar to the tip in the first variant D) and the inner surface of the cylinder. G.

Gradually decreasing, as the piston moves upward, the flow areas of these slots and the presence of a certain volume of chamber D, as well as in the case described above, cause a gradual increase in pressure in cavity B. As a result, when the piston 2 reaches the upper position (Fig. 2a, point g) the pressure here will be significantly less than in instruments with a conventional work cycle.

Zan in the upper position, the piston 2 under the action of pressure from above packs down movement, making a working stroke.

Due to the progressive increase in the flow area of the segmented slots and the relatively slow piston movement 2, the initial period of the forward stroke, the pressure in the cavity will increase smoothly and a moment will come (Fig. 2a, point 3) when it reaches the maximum value close to the network one. In the future, as the speed of the piston 2 increases, the pressure in this space will gradually fall.

Continuing the downward movement, the piston 2 will block the access of air into the cavity B (Fig. 2a, point ") and the process of pure expansion will take place in it.

After closing the window O (fig. 26, point k), the free air in the cavity B is compressed, and from the moment the valve 5 of the channel I is opened (fig. 26, point l), compressed air will flow into this cavity 5 from the network.

After some time, the piston 2 will open the window O (Fig. 2a, point m), as a result of which the exhaust from cavity B will occur, and the pressure in it will drastically decrease to atmospheric. Overcoming the resistance from below, piston 2 will strike but tool 3 and the above described process will be repeated.

From this it can be seen that the needle valve allows the user to use the non-channel cylinder and reduce the size of the instrument with a relatively large course of its Norsh.

Subject invention

Q A pneumatic percussion instrument equipped with a piston located in a cylinder differential with a groove in the middle part of a piston dividing the indicated cylinder into forward and reverse cavities and an exact distance from which the forward motion is connected to the air passage and the return cavity, and the weft cavity is connected to the exhaust port and is provided at the rear end with a chamber, periodically communicating through the groove of the port.

0 with an air inlet line, characterized in that, in order to quench the impact of a smooth air overpressure in the chamber of the intermediate cavity in the shaft of the reverse and forward stroke of the piston, the middle part of the piston is made with a cross section decreasing to its shank.

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