JP4487713B2 - Impact tool - Google Patents

Description

  The present invention is an impact tool such as an electric hammer that performs various operations such as crushing and suspending work materials such as concrete, and prevents continuous impact movement (hereinafter referred to as “empty strike”) in an unloaded state. The present invention relates to a striking tool having an anti-blank function.

  2. Background Art A hammering tool such as an electric hammer that is driven by a motor as a driving source and performs various operations such as crushing and lifting of a work material such as concrete is widely known (see, for example, Patent Document 1). An example of such an impact tool is shown in FIGS.

  That is, FIG. 7 is a longitudinal sectional view showing a part of a conventional impact tool 1 ′, and FIG. 8 is a longitudinal sectional view of a tip portion of the impact tool 1 ′. In the illustrated impact tool 1 ′, FIG. 7, the rotation of the motor 3 as a drive source housed in the motor casing 2 is transmitted to the crankshaft 8 by the pinion 5 in the gear cover 4, the counter gear 6 and the final gear 7. Driven by rotation. Then, the rotation of the crankshaft 8 is converted into a reciprocating linear motion of the piston 10 by the connecting rod 9, and the air pressure in the air chamber 12 defined by the piston 10 in the striker 11 is reciprocated by the piston 10. Therefore, the striker 11 reciprocates in the cylinder case 13 and intermittently collides with the intermediate element 14, so that the tip tool 16 is slidably fitted in the tip tool holding member (holder) 15. The striking force is transmitted from the meson 14, and the tip tool 16 performs necessary work such as crushing or hanging of a work material such as concrete.

  By the way, this kind of striking tool 1 ′ is provided with a function of preventing idling, and a C-ring-shaped gripping member (mouse) 17 is provided in the cylinder case 13 as means for that purpose. That is, when the thrust to the striker 11 side applied to the tip tool 16 is released (hereinafter, referred to as “no load”), the intermediate piece 14 and the striker 11 move to the tip tool 16 side. As shown in FIG. 3, the striker 11 is gripped by the gripping member 17 and its sliding is locked, so that the striker 11 is not interlocked with the movement of the piston 10, thereby preventing so-called idling.

Japanese Utility Model Publication No. 60-172681

However, in the conventional idling prevention structure, the air in the sealed space S ′ formed inside the gripping member 17 is compressed by the striker 11, so that the inside of the sealed space S ′ becomes high pressure and hits when no load is applied. In some cases, the child 11 was not gripped by the gripping member 17 and an empty shot occurred. Further, even when the striker 11 is gripped by the gripping member 17 as shown in FIG. 8 when there is no load, the compressed air in the sealed space S ′ acts as an air spring to push the striker 11 back and hold the gripping member 17. There is a possibility that the striker 11 will not be gripped and the idle strike will occur. When the idle driving occurs, the striker 11 is not only the operability is impaired to continuously strike the body, causing reduction of the service life of the body.

  The present invention has been made in view of the above problems, and an object thereof is to provide a striking tool capable of reliably preventing idling and improving operability and main body life.

In order to achieve the above object, according to the first aspect of the present invention, an impactor is slidably fitted in a cylinder case, and rotation of a motor as a drive source is caused to move within the impactor of a piston via a crankshaft. The reciprocating motion is converted into a reciprocating motion, and the striking force is transmitted to the tip tool by the pressure fluctuation in the air chamber formed between the piston and the striking element to perform a predetermined work, and the striking element is gripped by the gripping member. In the striking tool having a blanking prevention function for fixing it, a first air passage is formed in at least one of the outer periphery of the striking member or the inner periphery of the gripping member, and is defined by the striking member and the gripping member. The air in the space is allowed to escape through the air passage so that the pressure of the air in the space does not increase, and a plurality of spaces are provided between the outer periphery of the striker and the inner periphery of the cylinder case behind the first air passage. of Forming a second air passage, characterized in that the air passing through the first air passage to discharge continuously the air in the space by discharging through the second air passage.

According to a second aspect of the present invention, there is provided a shank sleeve that transmits the striking force of the striking element to the tip tool via the intermediate element and slidably holds the intermediate element, and the striking element is gripped by the gripping member. In this state, air passages for releasing the air in the space defined by the striker, the gripping member, and the shank sleeve to the outside of the space are formed in the outer periphery of the shank sleeve, the gripping member, and the inner periphery of the cylinder case . It is characterized by that.

According to a third aspect of the present invention, in the state where the striker is gripped by the gripping member, an air passage for releasing the air in the space defined by the striker and the gripping member to the outside of the space is gripped. It was formed in the outer periphery of a member and the inner periphery of a cylinder case .

According to the present invention, since the air in the space defined by the striker and the gripping member is always released outside the space through the first air passage, the air is compressed by the striker in the space. In addition, the striker is securely gripped by the gripping member when there is no load, and the striker once gripped by the gripping member is not pushed back by the air pressure in the space and does not come off the gripping member. Further, a plurality of second air passages are formed between the outer periphery of the striker behind the first air passage and the inner periphery of the cylinder case, and the air passing through the first air passage is discharged through the second air passage. Since it did in this way, even if a striker rotates, the air in the said space comes to be discharged | emitted reliably. For this reason, the hitting element is always securely held and fixed to the holding member when there is no load, and the idling is reliably prevented, and the operability of the hitting tool and the life of the main body are improved.

  Embodiments of the present invention will be described below with reference to the accompanying drawings.

<Embodiment 1>
1 is a longitudinal sectional view of a tip of an impact tool according to Embodiment 1 of the present invention, and FIG. 2 is a sectional view taken along line AA in FIG.

For implementation the basic configuration of the impact tool 1 according to the first is similar to that of a conventional impact tool 1 'shown in FIGS. 7 and 8, is omitted again explanation for this characteristic of the present invention Only those parts will be described.

The front end portion of the cylinder case 13 is mounted concentrically cylindrical tip tool holding member (holder) 15 extending therefrom horizontally by multiple bolts 18, on both sides of the rear end flange 15a, Ring-shaped cushioning materials 19 and 20 made of an elastic body such as rubber are interposed.

Further, a shank sleeve 21 is disposed at the front end portion in the cylinder case 13, and the meson 14 is inserted and held in the center portion of the shank sleeve 21 so as to be slidable in the front-rear direction. the rear end surface of the tip tool 16 that its rear end to a tip end tool holding member 15 is inserted and held in contact with the rear end is in the normal blow you contact the front end surface of the striker 11. Further, behind the shank sleeve 21, a C-ring-shaped gripping member (mouse) for fixing the striker 11 when no load is applied to the tip tool 16 when no load is applied (non-working) to prevent idling. ) 17 is arranged. Note that the inner peripheral surface of the gripping member 17 forms a tapered surface whose diameter increases toward the rear.

  Thus, a space S defined by the front end face of the striker 11 and the rear end faces of the shank sleeve 21 and the intermediate element 14 is formed inside the gripping member 17. 11 communicates with a plurality of air passages 23 formed between the cylinder case 13 and the striker 11 via air passages 22 formed in the axial direction in a part of the outer periphery of the head 11. Here, as shown in FIG. 2, the air passage 22 is formed by cutting a part of the outer periphery of the striker 11 into a flat surface 11 a that is long in the axial direction.

  By the way, the gripping member 17 is slightly movable in the axial direction along the inner peripheral surface of the cylinder case 13, and a ring-shaped damper 25 is interposed between the rear end surface and the cylinder case 13 via a washer 24. It is installed. Here, the damper 25 is for alleviating the impact generated when the intermediate element 14 moves to the striker 11 side (rear), and the washer 24 has a notch portion of the C-ring-shaped gripping member 17 as a damper. This is for preventing the damper 25 from being damaged by directly hitting it.

  On the other hand, a fitting hole 15b having a regular hexagonal cross section is provided through the front half of the tip tool holding member 15 in the front-rear direction, and a hexagonal columnar fitting portion 16a formed at the rear of the tip tool 16 is a fitting hole. The tip tool 16 is prevented from being rotated by being inserted and fitted into 15b. A rear end portion 16b extending rearward from the fitting portion 16a of the tip tool 16 is formed in a columnar shape, and an outer periphery thereof is slidably held by a sleeve 26.

  Further, a rotatable round bar-shaped retaining member 27 is provided in a direction perpendicular to the axis (perpendicular to the plane of FIG. 1) on the upper front end of the tip tool holding member 15. Is formed with a flat surface 27a. The retaining member 27 is intended to prevent the tip tool 16 from slipping by engaging with an engagement groove 16c formed in the fitting portion 16a of the tip tool 16 in the front-rear direction as shown in the figure. The tip tool 16 can be attached and detached by rotating it 180.degree. From the state shown in the figure so that the flat surface 27a faces the tip tool 16. FIG.

In the impact tool 1 according to the first implementation, a within impact tool 1, the portion other than the motor casing 2 lubricating oil is sealed such as grease, in order to prevent the lubricating oil from leaking The shank sleeve 21 is provided with two O-rings 28 that are in sliding contact with the outer peripheral surface of the intermediate element 14.

And Thus, in the impact tool 1 according to the first implementation, as in conventional impact tool 1 'shown in FIGS. 7 and 8, the piston 10 is reciprocated in the longitudinal direction in the striker within 11, The air pressure in the air chamber 12 formed in the striker 11 varies. The impact element 11 reciprocates back and forth in the cylinder case 13 due to fluctuations in the air pressure in the air chamber 12 and intermittently collides with the intermediate element 14, so that an impact force is transmitted from the intermediate element 14 to the tip tool 16. Then, the tip tool 16 to which the impact force is transmitted performs various operations such as crushing and hanging of a work material such as concrete.

By the way, in the no-load state (non-working time) when the thrust to the striker 11 side applied to the tip tool 16 is released because the tip tool 16 is separated from the work material after the work is finished, the striking force As shown in FIG. 1, the striking element 11 is gripped by the gripping member 17, and at this time, the striking element 11 and the gripping member 17 define it. The air in the space S is pushed out by the striking element 11 and escapes to the plurality of air passages 23 between the cylinder case 13 and the striking element 11 through the air passage 22 as indicated by arrows in FIG. In the space S, air is not compressed by the striker 11. As a result, at the time of no load striker 11 it can be reliably gripped by the gripping member 1 7, also disengaged from the gripping member 1 7 striker 11 which is temporarily held by the gripping member 1 7 is pushed back by air pressure in the space S Therefore, the striker 11 is always securely gripped and fixed to the gripping member 17 when there is no load. This prevents the striker from being surely prevented, and improves the operability of the impact tool 1 and the life of the main body. Improvement is achieved.

<Embodiment 2>
Next, a second embodiment of the present invention will be described with reference to FIGS.

Incidentally, FIG. 3 and FIG. 4 is a longitudinal sectional view of the impact tool tip according to the second implementation, FIG. 4 is a sectional view taken along line B-B in FIG. 3, in these figures 1 and 2 The same elements as those shown are denoted by the same reference numerals, and description thereof will be omitted below.

In Embodiment 2 of implementation, the inner circumference of the air passage 22 gripping member 17 for releasing air from the space S at the time of no load when striker 11 is gripped by the gripping member 17 the washer 24, the damper 25 and the cylinder case 13 The other parts are the same as those in the first embodiment.

  Here, as shown in FIG. 4, the air passage 22 is formed in a concave groove (formed in the gripping member 17 in FIG. 4) in each of the gripping member 17, the washer 24, the damper 25, and the inner peripheral portion of the cylinder case 13. Only the concave groove 17a is shown).

By Thus, also in the second implementation, in the no-load the striker 11 is gripped by the gripping member 17, the air in the space S, shown by an arrow in FIG. 3 is pushed by the striker 11 Thus, the air is not compressed by the impactor 11 in the space S because the air is passed through the air passage 22 to the plurality of air passages 23 between the cylinder case 13 and the impactor 11. The member 17 is always securely gripped and fixed, and idling is reliably prevented, and the operability of the impact tool 1 and the life of the main body are improved.

<Embodiment 3>
Next, Embodiment 3 of the present invention will be described with reference to FIG.

Note that FIG. 5 is a longitudinal sectional view of the impact tool tip according to Embodiment 3 of implementation, and the same reference numerals are given to the same elements as those shown in FIG. 1 in FIG. 5, below, for their Description of is omitted.

In the third implementation, an air passage 22 for air to escape from the space at the time of no load when striker 11 is gripped by the gripping member 17, a notched groove 21a formed on the rear end face of the shank sleeve 21 cylinder It is comprised by the notch groove 13a formed in the inner peripheral part of case 13, and the other structure is the same as the said Embodiment 1. FIG. Here, the notch grooves 21a and 13a communicate with each other to form one continuous air passage 22.

And Thus, even in the third implementation, in the time of no load when striker 11 is gripped by the gripping member 17, the air in the space S, through the air passage 22 is pushed by the striker 11 shown Since it flows in the direction of the arrow and escapes to the plurality of air passages 23 between the cylinder case 13 and the striker 11, air is not compressed by the striker 11 in the space S, and is the same as in the first embodiment. The effect is obtained.

<Embodiment 4>
Next, a fourth embodiment of the present invention will be described with reference to FIG.

Note that FIG. 6 is a longitudinal sectional view of the impact tool tip according to the fourth implementation, and the same reference numerals denote the same elements as those shown in FIG. 1 also in FIG. 6, below, for their Description of is omitted.

In the fourth implementation, the striker 11 is formed through the air passage 22 for releasing air from the space S to no load to be gripped by the gripping member 17, in the radial direction to the front end of the gripping member 17 off The notch groove 17b and the notch groove 13a formed in the cylinder case 13 are used, and other configurations are the same as those of the first embodiment. Here, the two notched grooves 17b and 13a communicate with each other to form one continuous air passage 22.

And Thus, even in the fourth implementation, the time of no load when striker 11 is gripped by the gripping member 17, the air in the space S, through the air passage 22 is pushed by the striker 11 shown Since it flows in the direction of the arrow and escapes to the plurality of air passages 23 between the cylinder case 13 and the striker 11, air is not compressed by the striker 11 in the space S, and is the same as in the first embodiment. The effect is obtained.

  In the first to fourth embodiments described above, the case where the present invention is applied to the impact tool 1 adopting a configuration in which the pressure fluctuation in the air chamber 12 is transmitted to the tip tool 16 via the intermediate element 14 will be described. However, the present invention can be similarly applied to a striking tool that employs a configuration in which an intermediate member is not provided and an impact force accompanying air chamber pressure fluctuation is directly transmitted to the tip tool. Also in the tool, the same effect as described above can be obtained by discharging the air in the space defined by the tip tool and the striker inside the gripping member to the outside through the air passage.

By the way, the gripping member 17 is a component that expands outward in the radial direction when the striking element 11 is gripped. However, in the configuration of the second embodiment, a concave groove 17 a for providing the air passage 22 is formed in the gripping member 17. Therefore, the thickness of the concave groove 17a portion becomes thin, and the strength of the portion becomes lower than that of other portions. Further, in the configurations of the third and fourth embodiments, it is necessary to process the notch groove 13a for providing the air passage 22 in the inner peripheral portion of the cylinder case 13, but the processing is not easy.

  Therefore, the configuration of the first embodiment is most desirable. According to this configuration, the durability of the gripping member 17 is not reduced due to insufficient strength, and the processing for providing the air passage 22 is easy. .

  The present invention relates to a tool for performing a predetermined work by transmitting a striking force to a tip tool by a change in air pressure in an air chamber generated by a reciprocating motion of a piston in the striking element, and gripping the striking element with a gripping member. It can be applied to an electric hammer having an anti-blank function for fixing the lever and any other impact tool.

It is a longitudinal cross-sectional view of the impact tool front-end | tip part which concerns on Embodiment 1 of this invention. It is the sectional view on the AA line of FIG. It is a longitudinal cross-sectional view of the impact tool front-end | tip part which concerns on Embodiment 2 of this invention. It is the BB sectional view taken on the line of FIG. It is a longitudinal cross-sectional view of the impact tool front-end | tip part which concerns on Embodiment 3 of this invention. It is a longitudinal cross-sectional view of the impact tool front-end | tip part which concerns on Embodiment 4 of this invention. It is a longitudinal cross-sectional view which fractures | ruptures and shows a part of conventional hitting tool. It is a longitudinal cross-sectional view of a conventional impact tool tip.

Explanation of symbols

1 Blowing tool 3 Motor (drive source)
8 Crankshaft 9 Connecting rod 10 Piston 11 Strike
12 Air chamber 13 Cylinder case 13a Notch groove 14 Meson 15 Tip tool holding member (holder)
16 Tip tool 17 Holding member 17a Groove 17b Notch groove 21 Shank sleeve 21a Notch groove 22 Air passage 23 Air passage S Space

Claims (3)

A striking element is slidably fitted in the cylinder case, and the rotation of the motor as a driving source is converted into a reciprocating motion of the piston in the striking element via the crankshaft, and the piston and the striking element In a striking tool having a blanking prevention function for transmitting a striking force to a tip tool by a pressure variation in an air chamber formed between them and performing a predetermined work, and gripping the striking member with a gripping member and fixing it. ,
A first air passage is formed in at least one of an outer periphery of the striker or an inner circumference of the gripping member, and air in a space defined by the striker and the gripping member is passed through the first air passage. The air pressure in the space is prevented from increasing due to the escape, and a plurality of second air passages are formed between the outer periphery of the striker behind the first air passage and the inner periphery of the cylinder case. A striking tool characterized in that the air in the space is always discharged by discharging the air that has passed through the passage through the second air passage . A striking element is slidably fitted in the cylinder case, and the rotation of the motor as a driving source is converted into a reciprocating motion of the piston in the striking element via the crankshaft, and the piston and the striking element In a striking tool having a blanking prevention function for transmitting a striking force to a tip tool by a pressure variation in an air chamber formed between them and performing a predetermined work, and gripping the striking member with a gripping member and fixing it. ,
A shank sleeve is provided that transmits the striking force of the striking element to the tip tool via an intermediate element and slidably holds the intermediate element, and in a state where the striking element is gripped by the gripping member, said gripping member and said shank air passage shank sleeve for releasing the air in the space defined to the space outside of the sleeve, the outer and striking hammer you characterized in that formed on the inner periphery of the cylinder casing of the gripping member tool. A striking element is slidably fitted in the cylinder case, and the rotation of the motor as a driving source is converted into a reciprocating motion of the piston in the striking element via the crankshaft, and the piston and the striking element In a striking tool having a blanking prevention function for transmitting a striking force to a tip tool by a pressure variation in an air chamber formed between them and performing a predetermined work, and gripping the striking member with a gripping member and fixing it. ,
In the state where the striker is gripped by the gripping member, an air passage for releasing the air in the space defined by the striker and the gripping member to the outside of the space is provided on the outer periphery of the gripping member and the cylinder case. striking撃工instrument you characterized in that it is formed on the peripheral.

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