JPS5833066B2 - striking device - Google Patents

Description

[Detailed Description of the Invention] The present invention is configured such that a movable cylinder disposed within an outer cylinder is reciprocated by a crank mechanism, and a free piston is inserted into the movable cylinder so that the free piston can strike a workpiece. The purpose of this invention is to improve the durability and work performance of a striking device by appropriately inhaling, exhausting, and refueling an air chamber formed above a free piston inside a movable cylinder.

The present invention will be specifically described below based on embodiments shown in the drawings.

In the embodiment shown in FIGS. 1 and 2, a movable cylinder 2 with an open bottom end disposed inside an outer cylinder 1 is connected to a crank mechanism 3.
At the same time, the free piston 4 is fitted into the movable cylinder 2, and the air chamber 5 formed above the free piston 4 inside the movable cylinder 2 is formed in a sealed manner, so that the air in the air chamber 5 is This is a striking device configured to operate the free piston 4 and strike a work body 6 such as a chisel by utilizing the compression and repulsion of the air and the lifting action of the free piston 4 due to negative pressure. This is an implementation of the invention.

As will be described later, in this type of striking device, it is necessary to form the air chamber 5 so as to basically maintain a sealed state, but in the conventional example, it is formed in a completely sealed state. The air in the air chamber 5 reaches a high temperature within a short period of time due to the compression effect of the free piston 4 and the generation of frictional heat between the free piston 4 and the movable cylinder 2, and the air in the air chamber 5 contains lubricating oil. Since it is difficult to supply the fuel into the interior of the fuel cell 5, it causes a deterioration in work performance and also causes accidents such as burn-in, resulting in problems with durability.

In order to solve the problems of the conventional example, the present invention forms a communication part 8 near the top 9 of the movable cylinder 2, which communicates the air chamber 5 with the inner space 7 of the outer cylinder 1, and this communication part 8. A valve body 10 having a short stroke H is provided so as to be able to reciprocate and is configured to close the communication portion 8 at the top dead center D1 and the bottom dead center D2 of the valve body 10.
The air chamber 5 is characterized in that it is configured such that air is taken in or exhausted from the air chamber 5 through the communication portion 8 only when the air chamber 5 is moved.

In the embodiment shown in FIGS. 1 and 2, a valve insertion hole 11 is provided at the center of the movable cylinder top 9, and conical valve seats 12a are provided at the upper and lower ends of the hole.

12b, and upper and lower conical closure bodies 13a.

13b is supported in the valve insertion hole 11 so as to be able to reciprocate, and a plurality of communication holes 8a, 8a, . . . are bored around the insertion hole 11. .

The vertical movement of the valve body 10 is regulated within a certain range by the closing bodies 1.3a, 13b being seated on the valve seats 12a, 12b.

Also, when the valve body 10 moves upward, a certain amount of air is exhausted from the air chamber 5 to the outer cylinder inner space 7 through the circulation holes 8a, and when the valve body 10 moves downward, a certain amount of air is exhausted. is drawn into the air chamber 5 from the outer cylinder inner space 7 through the communication holes 8a, 8a, . . . .

During this intake, lubricating oil is supplied from the lubricating oil tank 14 at the top of the outer cylinder 1 to the outer cylinder inner space 7 through the oil supply felt 15, together with air, to the circulation hole 8a.
, 8a... into the air chamber 5.

The crank mechanism 3 includes a crank 16 and a connecting rod 19 that connects the crank 16 and the movable cylinder 2 via a crank pin 17 and a connecting pin 18.

Further, 20 is an O-ring, and 21 is a drive shaft that provides rotational driving force to the crank 16.

In the embodiment shown in FIG. 3, a sphere holding chamber 22 is formed in the center of a communication hole 8b provided in the top part 9 of the movable cylinder, and a sphere is disposed in this holding chamber 22 so as to be able to move up and down. This constitutes the valve body 10.

Next, the operation of the present invention will be explained based on FIGS. 4 to 7.

FIG. 4 shows a state in which the crank pin 17 is at the top dead center, and the movable cylinder 2 and the free piston 4 are in their respective uppermost positions.

At this time, the air in the air chamber 5 is in a high pressure compressed state, and the pressure difference between the air chamber 5 and the air 7 in the outer cylinder causes the valve body to
0 is at the top dead center and closes the communication portion 8.

When the movable cylinder 2 passes the top dead center and begins to descend, the elastic force of the compressed air in the air chamber 5 is added to the downward movement of the movable cylinder 2, causing the free piston 4 to descend at a speed higher than that of the movable cylinder 2.

FIG. 5 shows a state in which the crank pin 17 has moved 90 degrees from the top dead center.

Before and after this position, the pressure in the air chamber 5 changes from positive pressure to negative pressure.

At this time, as the pressure in the air chamber 5 changes, the valve body 10 moves downward, and a certain amount of air and lubricating oil flow into the air chamber 5.

Thereafter, the valve body 10 is at the bottom dead center position, and the communication portion 8 is closed.

FIG. 6 shows a state in which the crank pin 17 has reached the bottom dead center.

Before and after this, the free piston 4 strikes the work body 6.

Further, the valve body 10 is at the bottom dead center and closes the air chamber 5.

When the movable cylinder 2 passes the bottom dead center and begins to rise, since the air chamber 5 is under negative pressure, a force is generated to pull up the free piston 4, and the free piston 4, which has received the repulsive force at the time of striking, easily lifts the movable cylinder. Rise within 2.

FIG. 7 shows a state in which the crank pin 17 has moved 90 degrees from the bottom dead center.

Before and after this position, the pressure in the air chamber 5 changes from negative pressure to positive pressure.

At this time, as the pressure in the air chamber 5 changes, the valve body 10 moves upward, and a certain amount of air is discharged from the air chamber 5.

Thereafter, the valve body 10 is at the top dead center position, and the communication portion 8 is closed.

As described above, in the device of the present invention, the air chamber 5 is closed except for the short time shown in FIG. 5 and FIG.
The compression elastic action due to the compression of the air chamber 5 shown in the figure and the lifting action of the free piston 4 due to the negative pressure of the air chamber 5 shown in FIG. 6 are performed normally.

In addition, during one cycle, the air chamber 5 is taken in and out and oil is refilled, albeit for a short time and in a small amount, so the high temperature air in the air chamber 5 is gradually converted to low temperature and fresh air outside, and It is possible to prevent the inside of the room 5 from becoming abnormally high temperature.

Furthermore, since oil is continuously supplied into the air chamber 5, the free piston 4 can reciprocate smoothly.

Therefore, according to the present invention, air intake and oil supply into the movable cylinder can be carried out appropriately, and the durability and work performance can be dramatically improved compared to the conventional example.

[Brief explanation of the drawing]

The drawings show an embodiment of the present invention, FIG. 1 is a longitudinal side view, FIG. 2 is a longitudinal side view of the main part thereof, FIG. 3 is a longitudinal side view of the main part of another embodiment, and FIGS. FIG. 7 is a schematic explanatory diagram showing the operation of the present invention. 1... Outer cylinder 2... Movable cylinder 3... Crank mechanism, 4...
Free piston, 5...Air chamber, 6...
Working body, 7... Outer cylinder inner space, 8...
...Communication section, 10...Valve body.

Claims (1)

[Claims] 1. In a striking device configured such that a movable cylinder disposed within an outer cylinder is reciprocated by a crank mechanism, a free piston is inserted into the movable cylinder, and a workpiece is struck by this free piston. A communication part that communicates the air chamber formed above the free piston with the inner space of the outer cylinder is formed near the top of the movable cylinder, and a valve body with a short stroke is provided in this communication part so that it can freely reciprocate. The communication section is configured to be closed at the top dead center and bottom dead center of the body, and the air chamber is configured to take in or exhaust air through the communication section only when the valve body moves. Strike device.