JP3369844B2 - Rotary impact tool with idle hit prevention mechanism - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a structure of a rotary hammering tool, and more particularly to a rotary hammering tool having a blank hammering prevention mechanism capable of surely preventing blank hammering.

[0002]

2. Description of the Related Art A conventional rotary impact tool is shown in FIG. The tool part 10 attached to the tip is driven by a motor to rotate. When the tool portion 10 is pressed against a processing object such as concrete (during processing work), the tool portion 10 performs a striking operation in which the tool portion 10 reciprocates in the directions of arrows 90 and 91 in addition to the rotating operation to crush the processing object. Thus, FIG.
In the rotary impact tool shown in (1), the tool unit 10 performs only the rotating operation and does not perform the impact operation until the tool unit 10 is pressed against the machining target (during non-machining work).

The conventional rotary operation mechanism, impact operation mechanism, and idle prevention mechanism (prevention of impact operation of the tool portion 10 during non-machining work) of a rotary impact tool will be described below. The tool unit 10 is held by the intermediate member 3 so as to be movable in the axial direction,
This meson 3 is located in the cylinder 2. The cylinder 2 and the intermediate element 3 are spline-coupled by the spline portions 2G and 3G, and the intermediate element 3 cannot rotate independently of the cylinder 2, but the arrow 9 in the cylinder 2 causes the intermediate element 3 to rotate.
It can move in the 0, 91 direction.

A cylinder bevel gear 33 is fixed to the cylinder 2, and a transmission shaft bevel gear 32 of a transmission shaft 30 meshes with the cylinder bevel gear 33. The transmission shaft 30 is driven by a motor to rotate,
The cylinder 2 rotates via the transmission shaft bevel gear 32 and the cylinder bevel gear 33. As mentioned above, cylinder 2
And the intermediate member 3 are spline-connected, the intermediate member 3 is also rotated by the rotation of the cylinder 2, and the tool portion 10 is rotated.

On the other hand, a striker 9 and a piston 16 are held in the cylinder 2 so as to be movable in the directions of arrows 90 and 91. The crankshaft 26 is rotated by the drive of the motor, and the eccentric pin 28 is fixed to the eccentric position. The eccentric pin 28 and the piston 16 are connected via the connecting bar 17, and the piston 16 reciprocates in the directions of arrows 90 and 91 based on the rotation of the crankshaft 26.

FIG. 3 shows a machining operation, that is, the tool portion 10 is pressed against a machining object, and the intermediate element 3 and the impact element 9 are indicated by arrows 9.
The figure shows the state of movement in one direction. First in this state
The air pressure in the chamber 41 causes the striker 9 to reciprocate as the piston 16 moves. An O-ring 18 provided on the striker 9 and an O-ring 19 provided on the piston 16
The atmospheric pressure of the first chamber 41 is maintained by.

The hitting element 9 hits the intermediate element 3 in the direction of arrow 90, and the tool section 10 performs the hitting operation in addition to the rotating operation. The second chamber 42 formed in the tip direction of the striker 9 is always opened by the air vent hole 21 formed in the cylinder 2. Therefore, the air pressure in the second chamber 42 does not hinder the reciprocating movement of the striker 9.

During non-machining work in which the tool portion 10 is separated from the object to be machined, the blanking prevention is performed by the following mechanism. When the tool part 10 is separated from the processing target, the intermediate piece 3 is hit by the hitting piece 9 and moves in the direction of arrow 90 from the state shown in FIG. As a result, the striker 9 also has an arrow 90.
Move in the direction. An air vent hole 22 is formed in the cylinder 2. This air vent hole 22 is shown in FIG.
Although it is closed by the striker 9 as shown in FIG.
Open up.

In this way, the striker 9 moves to move the first chamber 4
1 is widened and the air vent hole 22 opens the first chamber 41, so that the reciprocating movement of the piston 16 is not transmitted to the striker 9, and the impact operation of the tool portion 10 during non-machining work is prevented. A steel ball 24 is provided on the inner peripheral surface of the cylinder 2, and the steel ball 24 is engaged with the hitting element groove 9a of the hitting element 9 to hold the position of the hitting element 9 during non-machining work.

When the machining operation is performed again, the tool portion 10
Is pressed against the object to be processed, the striker 9 moves in the direction of arrow 91, and is positioned in the state shown in FIG. As a result, the air vent hole 22 is closed again by the striker 9, and the reciprocating movement of the piston 16 is transmitted to the striker 9 by the air pressure in the first chamber 41. Then, the impact element 9 impacts the intermediate element 3, whereby the tool portion 10 performs the impact operation in addition to the rotation operation.

[0011]

The above-mentioned conventional rotary impact tool has the following problems. In the conventional rotary impact tool, the first chamber 41 is opened by the air vent hole 22 to prevent idling during machining work. However, in the air vent hole 22, the opening of the first chamber 41 is insufficient, and since the reciprocating movement of the striker 9 is suppressed, the striking operation of the meson 3 is indirectly stopped.
There is a problem that it is not possible to reliably prevent runaway.

Incidentally, as a conventional example of a striking tool, an actual tool shovel 62 is used.
There is one disclosed in Japanese Patent Publication No. 181382. This impact tool is shown in FIG. The striking tool crushes the object to be processed by performing only the striking operation without performing the rotating operation. Also in this impact tool, the piston 16 in the cylinder 48 reciprocates in the directions of arrows 90 and 91, and the impact element 9 is moved by the air pressure in the first chamber 41 to impact the intermediate element 45.

An intermediate groove 46 is formed in the intermediate element 45, and an O-ring 47 is provided on the inner peripheral surface of the cylinder 48. At the time of non-machining work in which the tool part 10 is separated from the machining target, the O-ring 47 is fitted in the meson groove 46,
The bounce of the meson 45 (movement in the direction of the arrow 91) is suppressed. By this, the movement cycle of the meson 45 is found,
Prevents runaway.

However, since this striking tool does not rotate, the cylinder 48 and the intermediate member 45 do not need or have the spline portions 2G and 3G as shown in FIG. Therefore, for example, the configuration shown in FIG. 4 cannot be directly applied to the conventional rotary impact tool. That is, when the cylinder 2 shown in FIG. 3 is provided with an O-ring for locking the intermediate member 3 and a groove is formed near the rear end of the intermediate member 3, the O-ring comes into contact with the spline portion 3G and the O-ring is The problem of wear arises.

Further, the front cap 6 shown in FIG.
When a ring is provided and a groove is formed in the vicinity of the tip of the intermediate piece 3 (in the vicinity of the O-ring 23), the front cap 6 shown in FIG. 3 does not rotate, and thus the O-ring wears due to contact friction with the intermediate piece 3.

SUMMARY OF THE INVENTION It is therefore an object of the present invention to provide a rotary hammering tool having a blank hammering prevention mechanism capable of reliably preventing blank hammering and avoiding wear of a locking member such as an O-ring.

[0017]

A rotary impacting tool having a blanking prevention mechanism according to a first aspect of the present invention has a cylinder engaging portion on an inner peripheral surface thereof, and is a cylinder which is rotated by being driven by a drive source. , An intermediate member that is located in the cylinder and that has a moving engaging portion that engages with the cylinder engaging portion and that holds the tool portion, and that engages the cylinder engaging portion and the moving engaging portion. In the state where the cylinder is maintained, it is provided with an intermediate member that is reciprocally moved along the rotation center line direction of the cylinder by being driven by a drive source. In a rotary striking tool to which a tool part that reciprocates based on movement is attached, a locking member is provided on the inner peripheral surface of the cylinder,
A member to be locked is formed on the meson, and the part to be locked is formed as a conical surface for restricting the movement of the meson during the working operation. By the reciprocating movement of the meson within the range where the locking member and the locking member are not engaged, the tool portion performs both the rotating operation and the reciprocating movement operation, and during non-machining work,
The locking member engages with the locking target, and the meson is removed from the drive source.
To limit movement to a position that receives the driving force of
Therefore, the tool portion does not perform the reciprocating movement operation but performs only the rotation operation, and the processing operation is performed by pressing the tool portion against the processing object, and the non-processing operation is performed by separating the tool portion from the processing object. , Is characterized.

According to a second aspect of the present invention, there is provided a rotary striking tool having an idle striking prevention mechanism, wherein the locking member includes the cylinder engaging portion and the moving member. It is characterized in that it is provided at a position where it does not abut on the joint.

[0019]

As described above, in the rotary impact tool having the idle striking prevention mechanism according to the first aspect of the present invention , the engagement member is provided on the inner peripheral surface of the cylinder, and the engagement target portion is formed on the intermediate member. .

During the working operation, the tool reciprocates within a range where the locking target portion and the locking member do not engage with each other, so that the tool portion performs both rotating operation and reciprocating operation. Also, it is locked during non-processing work
The locking member engages the target part, and the meson is driven from the drive source.
Reciprocating the tool part by limiting the movement to the position to receive force
No moving operation is performed, only rotation operation is performed.

As described above, when the locking member engages with the locking target portion, the intermediate element receives the driving force from the driving source.
Since the movement of the tool portion is restricted to a certain position, it is possible to reliably prevent idle driving, that is, reciprocating movement of the tool portion during non-machining work.

Further, during the working operation, the intermediate member reciprocates within a range where the locking target portion and the locking member do not engage with each other, so that the locking member does not interfere with the reciprocal movement of the intermediate member. Therefore, the rotation operation and the reciprocating movement operation of the tool portion during the machining work can be reliably performed. Furthermore
In addition, during non-machining work, the locking member engages the conical surface of the meson.
And directly suppress the movement of the meson holding the tool section.
Since it is controlled, it is possible to surely prevent the blank driving. Well
Also, the conical surface regulates the movement of the meson during processing work.
This conical surface is used as the locking target part.
We are using. This creates a new locking target
You don't have to.

In the rotary impact tool having the idle striking prevention mechanism according to the second aspect, the locking member is provided at a position where it does not contact the cylinder engaging portion and the moving engaging portion. Therefore, the locking member does not wear due to contact with the cylinder engaging portion or the moving engaging portion.

[0024]

BEST MODE FOR CARRYING OUT THE INVENTION An embodiment of a rotary impact tool having an idle-strike prevention mechanism according to the present invention will be described with reference to the drawings. FIG. 1 is a side sectional view of a rotary impact tool. Figure 2
Cylinder 2, meson 3, front cap 6 shown in FIG.
It is an enlarged sectional view of the vicinity, A shows the state at the time of processing work, B has shown the state at the time of non-processing work.

The tool unit 10 attached to the tip of the tool is driven by a motor 13 as a drive source to rotate. Then, when the tool portion 10 is pressed against a processing object such as concrete (during the working operation), the tool portion 10 performs a striking operation of reciprocating in the directions of arrows 90 and 91 in addition to the rotating operation to crush the processing object.

As described above, in the rotary impact tool according to the present embodiment, the tool portion 10 performs only the rotating operation and does not perform the impact operation until the tool portion 10 is pressed against the object to be machined (during non-machining work). Below, the overall configuration of the rotary impact tool in the present embodiment, the operation during machining work, and the operation during non-machining work will be described.

[Overall Structure] The tool unit 10 is attached to an intermediate member 3 which is a reciprocating member and is held so as to be movable in the axial direction. The intermediate member 3 is located at the tip of the cylinder 2. The cylinder 2 and the intermediate element 3 are splined by a spline portion 2G as a cylinder engaging portion and a spline portion 3G as a moving engaging portion, and the intermediate element 3 cannot rotate independently of the cylinder 2.
It is movable in the cylinder 2.

The cylinder 2 is rotatably held in the barrel 7 via a bearing 8. The tool unit 10 is attached coaxially with the rotation center line L1 of the cylinder 2. Further, the intermediate element 3 reciprocates along the direction of the rotation center line L1 (directions of arrows 90 and 91).

A front cap 6 is fixed to the tip of the barrel 7. The front cap 6 is attached to the meson 3.
An O-ring 23 is provided on the sliding surfaces of and to prevent the lubricating oil on the sliding surfaces from leaking to the tip portion of the front cap 6. A cylinder bevel gear 33 is fixed near the rear end of the cylinder 2, and a transmission shaft bevel gear 32 of a transmission shaft 30 meshes with the cylinder bevel gear 33. A transmission shaft gear 31 is also fixed to the transmission shaft 30.

When the trigger 14 of the handle 34 shown in FIG. 1 is grasped, the switch portion 15 is turned on and the motor 1
3 is rotationally driven. When the trigger 14 is released and returned, the switch unit 15 is turned off and the driving of the motor 13 is stopped. A motor shaft gear is formed on the motor shaft 25 of the motor 13. A crankshaft 26 is rotatably held in the body, and a motor shaft gear 25 meshes with a crankshaft gear 27 fixed to the crankshaft 26.

The above-mentioned transmission shaft gear 31 is also meshed with the crankshaft gear 27 of the crankshaft 26. That is, the rotational drive of the motor 13 is transmitted to the transmission shaft 30 via the crankshaft 26, and the transmission shaft bevel gear 32 of the transmission shaft 30 and the cylinder 2 are transmitted.
Is transmitted to the cylinder 2 by meshing with the cylinder bevel gear 33. As a result, the cylinder 2 is driven by the motor 13 to rotate.

On the other hand, the striker 9 and the piston 16 are held in the cylinder 2 so as to be movable in the directions of arrows 90 and 91. One end of a connecting bar 17 is connected to the piston 16. In addition, the crankshaft 26 described above
An eccentric pin 28 is provided at the eccentric position, and the other end of the connecting bar 17 is connected to the eccentric pin 28. By the eccentric pin 28 and the connecting bar 17, the rotation of the crankshaft 26 is converted into a reciprocating movement in the directions of arrows 90 and 91 and transmitted to the piston 16.

[During Machining Work] Next, the operation during the working work of the rotary impact tool in this embodiment will be described in detail. As described above, at the time of processing work, the tool part 10 is pressed against a processing target such as concrete, and the tool part 10 is rotated and hit to crush the processing target. 1 and 2A show the state of the rotary impact tool during the working operation.

As described above, the rotational drive of the motor 13 is
It is transmitted to the transmission shaft 30 via the crankshaft 26, and is transmitted to the cylinder 2 by the meshing of the transmission shaft bevel gear 32 of the transmission shaft 30 and the cylinder bevel gear 33 of the cylinder 2. As a result, the cylinder 2 rotates, the intermediate member 3 spline-coupled to the cylinder 2 also rotates, and the tool unit 10 performs a rotating operation.

The rotation of the crankshaft 26 is transmitted to the piston 16 via the eccentric pin 28 and the connecting bar 17 as reciprocating movement in the directions of arrows 90 and 91. When the piston 16 reciprocates, the piston 16 and the striker 9
The striking element 9 also reciprocates due to the change in atmospheric pressure in the first chamber 41 formed between the striking element 9 and.

Then, the striker 9 strikes the intermediate piece 3 in the direction of arrow 90, and the tool portion 10 performs a striking operation. The O-ring 18 provided on the striker 9 and the O-ring 19 provided on the piston 16 maintain the atmospheric pressure in the first chamber 41. Further, an air pressure adjusting hole 29 is formed in the cylinder 2, and the air pressure in the first chamber 41 is adjusted by the air pressure adjusting hole 29, so that the striker 9 can efficiently reciprocate.

As described above, at the time of machining work, the tool unit 1
0 performs both a rotating operation and a striking operation. In addition, as shown in FIG. 1, an air vent hole 22 is formed in the cylinder 2. However, the hammer 9 is pressed in the direction of the arrow 91 by the tool portion 10 and the intermediate piece 3 during the working operation,
The air vent hole 22 is closed by the striker 9.

The second chamber 42 formed in the tip direction of the striker 9 is always open by the air vent hole 21 formed in the cylinder 2. Therefore, the second chamber 4
The air pressure in 2 does not hinder the reciprocating movement of the striker 9.

[During non-machining work] During non-machining work in which the tool portion 10 is separated from the machining object, the striker 9 and the intermediate piece 3 move in the direction of arrow 90 from the state shown in FIG. FIG. 2B is an enlarged cross-sectional view of the vicinity of the cylinder 2, the intermediate element 3, and the front cap 6 during non-machining work. Note that the striker 9 and the like are omitted in FIG.

As shown in FIG. 2B, a cutout groove is formed at the tip of the cylinder 2, and a locking O-ring 4 which is a locking member is provided therein. The locking O-ring 4 has elasticity and is compressed by the intermediate element 3 as shown in FIG. 2A during the working operation.

The intermediate surface 3 has a conical surface 5 as an object to be locked.
Is formed, and the spline portion 3G is provided in the step-down portion. The conical surface 5 is the inner peripheral surface 2 of the cone of the cylinder 2.
It comes into contact with M and regulates the movement of the intermediate element 3 in the direction of arrow 91 during the working operation (see FIG. 2A).

During non-machining work in which the intermediate piece 3 has moved in the direction of arrow 90, the locking O-ring 4 is located at this step-down portion. In this case, the locking O-ring 4 and the spline portion 3G do not come into contact with each other. For this reason,
The locking O-ring 4 does not wear due to contact with the spline portion 3G.

When the locking O-ring 4 is located at the stepped-down portion of the intermediate member 3, the locking O-ring 4 is released from compression and returns to its shape by elasticity. And O for locking
The ring 4 engages the conical surface 5 of the meson 3 and limits the movement of the meson 3 in the direction of arrow 91. As a result, the intermediate member 3 and the tool portion 10 do not perform the striking operation, and it is possible to reliably prevent idle driving.

As described above, the conical surface 5 is for restricting the movement of the meson 3 in the direction of the arrow 91 during the working operation, and in the present embodiment, the conical surface 5 is used as the locking target portion. is doing. Thereby, it is not necessary to newly form the locking target portion.

During non-machining work, the striker 9 shown in FIG. 1 moves in the direction of arrow 90, the first chamber 41 expands, and the air vent hole 22 formed in the cylinder 2 communicates with the first chamber 41. As a result, the reciprocating movement of the piston 16 is not transmitted to the striker 9, and the striker 9 also stops moving in the directions of arrows 90 and 91.

Further, a steel ball 24 is provided on the inner peripheral surface of the cylinder 2, and the steel ball 24 is used for the striker groove 9 of the striker 9.
The movement of the striker 9 is suppressed by engaging with a. The steel ball 24 is pressed inward by an O-ring located outside. As described above, in the present embodiment, the movement of the striker 9 in the directions of the arrows 90 and 91 is also restricted during non-machining work, so that it is possible to more reliably prevent idle driving.

As described above, at the time of non-machining work, the locking O-ring 4 engages with the conical surface 5 of the intermediate member 3, and the tool portion 10
Since the movement of the intermediate element 3 which holds is directly suppressed, it is possible to surely prevent the blank driving. Even during this non-machining work, since the cylinder 2 is being rotated by the drive of the motor 13, the tool unit 10 only performs the rotating operation.

When the machining work is performed again, the tool unit 10
Is pressed against the processing target. Due to this pressing force, the intermediate member 3 moves in the direction of arrow 91, the locking O-ring 4 is compressed along the slope of the conical surface 5, and returns to the state shown in FIG. 2A. Further, the striker 9 also moves in the direction of the arrow 91, and the air vent hole 22
Is closed, and the reciprocating movement of the piston 16 is transmitted to the striker 9. In this way, the tool unit 10 can perform the striking motion in addition to the rotating motion.

During the working operation shown in FIGS. 1 and 2A, the intermediate element 3 reciprocates within a range in which the locking O-ring 4 and the conical surface 5 do not engage with each other. Therefore, during the working operation, the locking O-ring 4 and the conical surface 5 do not hinder the impact operation of the tool portion 10.

[Other Embodiments] In the above embodiment, the locking O-ring 4 as the locking member is provided on the cylinder 2 side, and the conical surface 5 as the locking target portion is on the intermediate 3 side. Had been formed. However, the locking member is replaced by the meson 3
May be provided on the side, and the locking target portion may be formed on the cylinder 2 side.

Further, in the above embodiment, the cylinder 2 is illustrated as the cylinder and the intermediate member 3 is illustrated as the reciprocating member, but other shapes and structures may be adopted. Further, although the locking O-ring 4 is illustrated as the locking member and the conical surface 5 is illustrated as the locking target portion, the present invention is not limited to this. That is, as long as it does not engage in the machining operation and engages in the non-machining operation to stop the reciprocating movement of the reciprocating member, the engaging member and the object to be engaged may have other shapes and structures. Can be adopted.

[Brief description of drawings]

FIG. 1 is a side sectional view showing an embodiment of a rotary impact tool having an idle-strength prevention mechanism according to the present invention.

2 is an enlarged cross-sectional view of the vicinity of a cylinder 2, an intermediate member 3, and a front cap 6 shown in FIG. 1, where A shows a state during a working operation and B shows a state during a non-working operation.

FIG. 3 is a side sectional view showing a conventional rotary impact tool.

FIG. 4 is a side sectional view showing a conventional striking tool.

[Explanation of symbols]

2 ... Cylinder 2G: Spline part 3 ... Meson 3G: Spline part 4 ... O-ring for locking 5 ... Conical surface 10: Tool section 13 ... Motor

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Claims (2)

(57) [Claims] 1. A cylinder that has a cylinder engaging portion on its inner peripheral surface, rotates when receiving a drive from a drive source, and a moving member that is located in the cylinder and engages with the cylinder engaging portion. An intermediate member for holding a tool portion having a joint portion, which is driven by a drive source in a state where the engagement between the cylinder engaging portion and the moving engaging portion is maintained to rotate the cylinder. A rotary impact tool equipped with a tool part that reciprocates along the centerline direction, and that performs a rotary operation according to the rotation of the cylinder and that performs a reciprocal motion operation based on the reciprocal motion of the intermediate element. The inner peripheral surface of the is provided with a locking member, the intermediate member is formed with a locking target member, the locking target portion is a conical surface for restricting the movement of the intermediate core during processing work. Has been formed, During work, the tool part performs both rotational movement and reciprocating movement by the reciprocating movement of the meson within the range where the locking target portion and the locking member do not engage, and during non-machining work, The locking member engages with the locking target
Move the meson to the position where it receives the driving force from the driving source.
By restricting the operation , the tool part does not perform the reciprocating movement operation but only the rotating operation, and the tool part is pressed against the object to be processed during the processing operation, and the tool part is separated from the object to be processed. A rotary impact tool having an idle-driving prevention mechanism, characterized in that it is used during non-machining work. 2. A rotary impact tool having an idle-driving prevention mechanism according to claim 1, wherein the locking member is provided at a position where it does not contact the cylinder engaging portion and the moving engaging portion. A rotary impact tool having an idle hit prevention mechanism.