JP2726643B2 - Impact tool - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a striking tool, and more particularly, to a striking tool prevention mechanism capable of reliably preventing idling.

[0002]

2. Description of the Related Art In general, impact tools are widely known as tools for crushing concrete or the like.

[0003] In such a hammering tool, it is not desirable to operate the hammer in a no-load state because of safety, durability of the tool, etc., and various hitting prevention mechanisms have been proposed. FIG. 6 is a schematic view of a hitting tool showing a conventional idle hit prevention mechanism. In the figure, reference numeral 101 denotes a main body casing, in which a cylinder 102 is provided. An adapter 10 is provided at the lower end of the cylinder 102 in the drawing.
3 is provided so as to be movable in the vertical direction in the figure, and a tool 104 is mounted on the adapter 103. on the other hand,
A hammer 105 is provided in the cylinder 102 so as to be movable in the axial direction (vertical direction in the figure). Above the hammer 105 in the figure, a piston 107 reciprocated vertically by a motor 106 in the figure. It is stored in the cylinder 102. Further, on the side wall of the cylinder 102, an air intake / exhaust hole 102a, an idle hit prevention hole 102b,
2c are sequentially drilled from the bottom in the figure.

[0004] In the hitting tool constructed as described above, the idle hit prevention hole 102b is always in contact with the hammer 105 during operation.
Is blocked by On the other hand, when the operation is not being performed, the hammer 105 does not move even if the piston 107 reciprocates because the idle hit prevention hole 102b is open, so that the idle hit is prevented. .

[0005]

However, in FIG. 7, the upper end surface of the hammer 105 in the drawing and the hitting prevention hole 102b are shown.
When the length 1 is short, the hammer 105 moves upward in the drawing due to the reaction force caused by the collision between the adapter 103 and the main body casing 101 and the collision between the tool 104 and the main body casing 101, and the hammer 105 is disengaged from the idle hit hole. There is a problem in that the block 102b is closed again, resulting in an idling state. Further, when the length 1 is increased, there is a problem that a hitting operation is desired, but a hitting phenomenon is caused.

SUMMARY OF THE INVENTION The present invention has been made in view of the above problems, and has as its object to provide a striking tool capable of more reliably preventing an idling phenomenon and a non-striking phenomenon.

[0007]

SUMMARY OF THE INVENTION The present invention provides a main body casing, a cylinder housed in the main body casing,
An adapter provided at one end of the cylinder so as to be movable in the axial direction of the cylinder, a tool attached to the adapter, and a hammer housed in the cylinder so as to be movable in the axial direction and hitting the adapter. A piston movably provided on the other end side of the cylinder, and the cylinder has an intake / exhaust hole opened and closed by the hammer, a first anti-hitting hole, and an air adjustment hole. In the impact tool, a second non-hitting hole is formed between the first non-hitting hole and the air adjustment hole; The opening area of the prevention hole is set to 1/10 to 1/3.

[0008]

An embodiment of the present invention will be described below with reference to the accompanying drawings. FIG. 1 is a schematic view of a striking tool according to the present invention. In the figure, reference numeral 1 denotes a main body casing, in which a cylinder 2 is provided. An adapter 3 is provided at the lower end of the cylinder 2 in the drawing.
Is provided so as to be movable in the vertical direction in the figure, and a tool 4 is mounted on the adapter 3. On the other hand, cylinder 2
A hammer 5 is provided in the inside so as to be movable in an axial direction (vertical direction in the figure). Above the hammer 5 in the figure, a piston 7 reciprocated vertically by a motor 6 in a cylinder 2 is provided. Is housed inside. Also, cylinder 2
A suction / exhaust hole 2a, a first idle hit prevention hole 2b, a second idle hit prevention hole 2d, and an air adjustment hole 2c are formed in the side wall in this order from below in the figure. Here, the opening area of the second blank hit prevention hole 2d is set to 1/10 to 1/3 of the opening area of the first blank hit prevention hole 2b.

In the thus configured impact tool,
When performing the work, when the tool 4 is pressed against concrete or the like and the tool 4 is moved upward in the figure, the hammer 5 is moved upward in the figure via the adapter 3. Then, the hammer 5 closes the first blank hit prevention hole 2b and the second blank hit prevention hole 2d. At this time, the air in and out of the space 8 flows only through the air adjusting hole 2c having a small hole diameter. Therefore, when the piston 7 moves upward in the drawing, the pressure in the space 8 becomes a negative pressure, and the hammer 5 is further pulled up. Then, the hammer 5 also closes the air adjusting hole 2c. When the piston 7 moves downward in the drawing in this state, the air in the space 8 is compressed, the hammer 5 is driven out, and the adapter 3 is hit. By repeating such an operation, a striking operation is performed.

Next, the operation when the operation is stopped will be described. When the main body is lifted from the hitting operation, the hammer 5 opens the first anti-hitting hole 2b, and the hammer 5
And the tool 4 are pushed forward (downward in the figure). At this time, the inside of the space 8 is maintained at the atmospheric pressure.
Reciprocation is stopped, and the work is stopped.

Here, if the hammer 5 reacts,
Even if it moves slightly upward and closes the first blank hit prevention hole 2b, the space 8 can be maintained at the atmospheric pressure because the second blank hit prevention hole 2d is formed, and the blank hit phenomenon occurs. It can be reliably prevented.

The reason why the opening area of the second blank hit prevention hole 2d is set to 1/10 to 1/3 of the opening area of the first blank hit prevention hole 2b is as follows. That is, when the opening area of the second non-hitting hole 2d is smaller than 1/10 of the opening area of the first non-hitting hole 2b, the second non-hitting hole 2d is raised when the main body is lifted from the hitting operation. The supplied air is not sufficient, and the space inside the space 8 formed between the hammer 5 and the piston 7 becomes negative pressure due to the retraction (upward movement in the figure) of the piston 7, and the hammer 5 is retreated. This is because it is in an idling state. Further, when the opening area of the second non-hitting hole 2d is larger than 1/3 of the opening area of the first non-hitting hole 2b, the second non-hitting hole 2d is formed during a normal hitting operation.
d, the inflow and outflow of air into and from the space 8 increases, the pressure change in the space 8 is small, and the impact force decreases,
There is a risk of causing no impact.

FIG. 2 is a graph showing the piston displacement, the air pressure in the space 8 and the kinetic energy of the hammer 5 during the striking operation of the conventional striking tool. 5 is a graph showing displacement, air pressure in a space 8, and kinetic energy of a hammer 5; The conditions are as follows: the suction / exhaust hole 2a has a diameter of 3.7 mm × 4, the first blank hit prevention hole 2b has a diameter of 2.5 mm × 8, the second blank hit prevention hole 2d has a diameter of 2.5 mm × 1, and the air adjustment hole 2c has a diameter of 2.5 mm × 8. 1.0m diameter
m × 1. As can be seen from FIGS. 2 and 3, the air pressure in the space 8 and the kinetic energy of the hammer 5 hardly change between the case where the second anti-hitting hole 2d is provided and the case where it is not provided. It does not affect the hitting action of the player.

FIG. 4 is a diagram showing the displacement of the piston and the position of the rear end face of the hammer 5 when the striking operation of the conventional striking tool is interrupted. FIG. It is a figure which shows piston displacement and the position of the rear end surface of hammer 5. The conditions are the same as those in the above-described experimental example. Even if the tool is lifted at the point A as described above, the hitting tool having the conventional structure may fall into an idling state, whereas in the case of the present invention, the hammer 5 reliably stops,
An empty shot can be prevented.

[0015]

According to the present invention having the above-mentioned construction, the present invention has the effects of reliably preventing idle hits, and further improving safety and durability.

[Brief description of the drawings]

FIG. 1 is a schematic view of a striking tool according to the present invention.

FIG. 2 is a graph showing piston displacement, air pressure in a space, and kinetic energy of a hammer during a striking operation of a conventional striking tool.

FIG. 3 is a graph showing piston displacement, air pressure in a space and kinetic energy of a hammer during a striking operation of the striking tool of the present invention.

FIG. 4 is a diagram showing a piston displacement and a position of a rear end surface of a hammer when a hitting operation of a conventional hitting tool is interrupted.

FIG. 5 is a diagram showing the piston displacement and the position of the rear end face of the hammer when the striking operation of the striking tool of the present invention is interrupted.

FIG. 6 is a schematic view of a conventional impact tool.

FIG. 7 is a schematic view of a main part of a conventional impact tool.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 ... Main body casing 2 ... Cylinder 2a ... Intake / exhaust hole 2b ... 1st blank hit prevention hole 2c ... Air adjustment hole 2d ... 2nd blank hit prevention hole 3 ... Adapter 4 ... Tool 5 ... Hammer 7 ... Piston 8 ... Space

Claims (2)

(57) [Claims] 1. A main body casing, a cylinder housed in the main body casing, an adapter provided at one end of the cylinder so as to be movable in an axial direction of the cylinder, and a tool attached to the adapter. A hammer that is housed in the cylinder so as to be movable in the axial direction and that hits the adapter; and a piston that is movably provided on the other end of the cylinder, and is opened and closed by the hammer in the cylinder. In a striking tool having an intake / exhaust hole, a first non-hitting hole, and an air adjusting hole, a second non-hitting hole is formed between the first non-hitting hole and the air adjusting hole. A striking tool characterized by being made. 2. The striking tool according to claim 1, wherein the opening area of the second anti-hitting hole is set to 1/10 to 1/3 of the opening area of the first anti-hitting hole. .