JP4551302B2 - Pneumatic reciprocating tool. - Google Patents

Description

  The present invention relates to a pneumatic reciprocating tool such as a hand-held saw driven by compressed air.

  Various types of pneumatic reciprocating tools of this type have been developed. For example, a cylindrical housing and a fixed shaft extending from the rear end of the housing in the axial direction of the housing. A first piston that is slidable along the fixed shaft, and a second piston that is provided on the front end side of the first piston and has a recess that slidably receives the first piston in the axial direction. And a tool holding member drivingly connected to the second piston, and the compressed air is supplied between the first and second pistons via a compressed air supply path extending along the axis of the fixed shaft. There is a tool that drives (see, for example, Patent Document 1).

  In this reciprocating tool, the first piston is slidably engaged with the fixed shaft, and the second piston is slidably engaged with the first piston, thereby aligning the fixed shaft.

However, for example, when the tool held at the tip is a saw, a lateral load in a direction perpendicular to the axis of the fixed shaft is applied to the second piston, the first piston, and the fixed shaft through the saw. Therefore, in the tool having the structure as described above, this lateral load causes excessive sliding resistance between the first piston and the second piston and sliding resistance between the first piston and the fixed shaft. There is a risk that the sliding between them will not be performed smoothly.
JP-A-2005-205514

In view of the above problems, even if a lateral load on the tool held in the tip, the first and second pistons, and pneumatic sliding between the respective fixed shaft were to smoothly perform An object of the present invention is to provide a reciprocating tool.

That is, the present invention
A tubular housing;
A fixed shaft extending forward in the housing from the rear end side of the housing;
A cylindrical first piston slidable along the fixed shaft;
A second piston provided in alignment with the first piston in the axial direction of the fixed shaft on the front end side of the first piston;
A tool holding member that is drivingly connected to the second piston and holds a tool on the front end side of the housing;
First urging means for urging the first piston forward;
Second urging means for urging the second piston backward;
A compressed air supply path for supplying compressed air between the first and second pistons through the fixed shaft;
Have

The first and second pistons are slidably engaged in the axial direction, and the compressed air supplied therebetween opposes the first and second urging means, respectively, and Exhaust gas that is driven forward and is arranged to exhaust compressed air supplied between the first and second pistons to the outside of the housing when the first and second pistons are separated by a predetermined distance. Has a passage,
First piston, a first tubular member having an inner peripheral surface slidingly engages the outer circumferential surface of the fixed shaft, disposed in the second piston-side with respect to the first tubular member, the is aligned with the first cylindrical member and the axial line direction, and a second tubular member which is displaceably set in the radial direction with respect to the fixed shaft,
Sliding engagement of the first and second pistons in the axial direction is performed between the second tubular member of the first piston and the second piston;
The first urging means urges the first cylindrical member and the second cylindrical member forward via the first cylindrical member,
The pneumatic drive reciprocating tool is characterized in that the compressed air drives the second cylindrical member and the first cylindrical member rearward through the second cylindrical member. provide.

That is, in this pneumatic reciprocating tool, Suridogakari the outer peripheral surface of the inner peripheral face of the fixed shaft of the alignment of the slide portion relative to the axis of the fixed shaft of the first piston first tubular member since the the to keep the case, even when the horizontal load is applied to the second piston, a second tubular member of the first piston, which is inclined together with the second piston in response to the lateral load smooth with sliding is maintained between the first tubular member of the first piston which is connected to them are not affected by the lateral load, to maintain a smooth sliding of the fixed shaft It becomes possible.

In one example,
A sealing ring is provided between the first and second tubular members and seals between them. Furthermore, the first and second tubular member has first and second annular surfaces facing each other in the axial line direction, respectively, sandwiched between the sealing rings of the first and second annular surface To be.

In another example,
Forward portion of the first tubular member and the rear portion of the second tubular member is to be fitted in the axial line direction in the first piston, the sealing ring, with fitted in radially mutually It is sandwiched between the peripheral surfaces of the front portion and the rear portion facing each other.

More specifically,
It said first piston second tubular member of has an inner peripheral surface of the larger diameter than the inner circumferential surface of the first tubular member, to the fixed shaft and coaxially around said fixed shaft Can be set.

In this case, by increasing the inner diameter of the second tubular member, when the lateral load is applied, and the second tubular member and the second piston is it possible to tilt together.

As another aspect,
You can first piston second tubular member of to extend forward from a position ahead of or front end position from the front end position of the fixed shaft.

That is, by setting the second tubular member in this way, without fitting results relative to the fixed shaft of the second tubular member, therefore, even if inclined second tubular member This is to prevent interference with the fixed shaft.

According to the present invention, even if a lateral load on the tool attached to the tip, without Kakekara is lateral load to the first tubular member of the fixed shaft and the sliding engagement with that first piston, thus said with smooth sliding on the fixed shaft of the first tubular member is maintained, since the second tubular member of the first piston will be inclined together in response to lateral loads together with the second piston, Smooth sliding between them is maintained.

  An embodiment of a pneumatic reciprocating tool when the present invention is applied to a saw will be described in detail with reference to the accompanying drawings.

  As shown in FIG. 1, a pneumatic reciprocating tool 10 according to the present invention includes a cylindrical housing 12, a fixed shaft 14 that extends forward in the axial direction of the housing from the rear end of the housing, and a fixed shaft 14. A cylindrical first piston 18 slidable along the second piston 20, a second piston 20 provided on the front end side of the first piston, and the second piston 20 connected to the front end of the housing 12 And a tool holding member 22 that extends forward in the axial direction and holds a tool (not shown) at the front end.

The first piston 18 includes a first tubular member 18a having an inner peripheral surface slidingly engages the outer circumferential surface of the fixed shaft 14 is aligned with the first tubular member and the axial line direction, in FIG. 2 as clearly shown, larger diameter than the inner circumferential surface of the first tubular member 18a, a second cylindrical member 18b having an inner peripheral surface spaced from the outer peripheral surface of the fixed shaft, the first and second tubular member 18a, is set between 18b, it is composed of a O-ring 18c to achieve sealing between them. Specifically, the O-ring 18c is sandwiched in the first and second tubular member 18a, 18b first and second between annular surface 18a-1 and 18b-1 of facing each other in the axial line direction Has been. The first piston 18 is urged forward by first urging means (coil spring) 24, and the second piston 20 is urged rearward by second urging means (coil spring) 26, as shown in FIG. In a state where compressed air is not introduced, the first and second pistons 18 and 20 are brought closer to each other by the first and second urging means.

  The fixed shaft 14 is fixed to a rear end member 28 that closes the rear end of the housing 12. The fixed shaft 14 extends through the rear end member 28 and is compressed from a compressed air introduction passage 30 that communicates with a compressor (not shown). A compressed air supply path 32 that receives air and supplies the air between the first and second pistons 18 and 20 is provided. A ball-shaped valve body 34 is provided in the compressed air supply path 32, and the compressed air supply is provided at an open position (FIG. 1) for opening the compressed air supply path 32 and at the front end side of the housing from the open position. The valve body 34 is displaceable between a closed position where the compressed air supply path 32 is closed by sealingly engaging the front end portion of the path 32, and the valve body 34 is provided by a compression spring 36 provided in the compressed air supply path 32. It is biased toward the closed position. On the other hand, the tool holding member 22 fixed to the second piston 20 has a rear end aligned with the compressed air supply path 32 and protrudes rearward from the second piston 20, and the first and second pistons. A valve opening / closing operation unit 38 that operates opening / closing of the valve body 34 in accordance with the movements of 18 and 20 is provided.

The second piston 20 has a cylindrical wall 20a extending rearward, the second tubular member 18b is inserted in the first piston 18, is engaged slidably engaged with the inner peripheral surface of the cylindrical wall 20a ing. The cylindrical wall 20a is provided with first to fourth exhaust ports 20b-1 to 20b-4 penetrating in the diametrical direction and spaced apart from each other in the axial direction. When compressed air is supplied between the first and second pistons 18 and 20 through the compressed air supply path 32, the first and second pistons 18 and 20 are respectively connected to the first and second urging means. Drives backward and forward against 24 and 26. As the drive proceeds, the first exhaust port 20b-1 to the second, third, and fourth exhaust ports 20b-2 to 20b-4 are sequentially arranged. The space between the first and second pistons 18 and 20 is communicated.

  A cylindrical exhaust port closing member 44 is provided between the inner peripheral surface of the housing 12 and the outer peripheral surface of the second piston 20, and can be displaced in the axial direction of the housing 12. A connecting pin 50 is fixed to the exhaust port closing member 44, and the connecting pin 50 passes through a through long hole 46 formed in the housing 12 so as to extend in the axial direction of the housing 12. It is slidably engaged with an annular groove 53 of a cylindrical adjustment member 52 mounted on the top. The adjusting member 52 is screw-engaged on the outer peripheral surface of the housing 12, and is screwed on the housing 12 to displace the exhaust port closing member 44 in the axial direction of the housing 12 via the connecting pin 50. Adjustable. That is, when the first and second pistons 18 and 20 are driven by the compressed air, the exhaust port closing member 44 sequentially opens the exhaust ports 20b-1 to 20b-4 as the second piston 20 is driven forward. Therefore, the exhaust port for exhausting compressed air from the space between the first and second pistons 18 and 20 is adjusted by adjusting the position of the exhaust port closing member 44 in the axial direction. It can be changed. Specifically, the more the exhaust port closing member 44 is set to the left position, the more the compressed air is exhausted through the left exhaust ports of the first to fourth exhaust ports 20b-1 to 20b-4. Therefore, the driving by the compressed air ends quickly and the driving stroke length is shortened.

  The compressed air exhausted from the exhaust port is exhausted to the outside of the housing 12 through the internal space 40 between the housing 12 and the fixed shaft 14 and the exhaust passage 42 formed in the rear end member 28. It has become.

In this pneumatic drive reciprocating tool 10, even if a lateral load is applied by pressing a tool attached to the tip, for example, a saw, to the work piece, the first piston 18 that is in sliding engagement with the fixed shaft 14. not Kakekara is lateral load to the first tubular member 18a, thus with smooth sliding of on the fixed shaft 14 of the first tubular member 18a is maintained, the second cylinder of the first piston 18 since Jo member 18b will be inclined together in response to lateral loads together with the second piston 20, smooth sliding between them is maintained.

  1 and 2, reference numeral 55 is an O-ring, 44a is an urging means (coil spring) for preventing rattling of the exhaust port closing member 44, and 57 is axially displaceable on the rear end member 28. An opening / closing member for opening / closing the compressed air introduction path 30 is shown.

  FIG. 3 shows a main part of another embodiment of the pneumatic reciprocating tool according to the present invention.

In this pneumatic reciprocating tool 10 is a front and rear portions of the second tubular member 18b of the first cylindrical member 18a in the first piston 18 is fitted in the axial line direction, the O-ring 18c is sandwiched between the peripheral surfaces 18a-2 and 18b-2 of the front portion and the rear portion that are fitted and face each other in the radial direction. Other configurations are substantially the same as those in the first embodiment.

  FIG. 4 shows still another embodiment of the pneumatic reciprocating tool according to the present invention.

In this pneumatic reciprocating tool 10, the second tubular member 18b of the first piston 18 is set from the front end near the fixed shaft 14 so as to extend forward.

This reciprocating tool, since the second tubular member 18b of the first piston 18 is set as described above with respect to the fixed shaft 14, results fit with respect to the fixed shaft of the second tubular member it is no, therefore, the second piston 20 is inclined by the lateral load, as the second tubular member 18b is inclined with it, there is no interference with the fixed shaft 14. Compared to the first embodiment, the second piston 20 is slidably accommodated, and there is only one exhaust port 20b, and therefore there is no exhaust port closing member 44. Further, the configuration is substantially the same except that there is no ball-shaped valve body 34 and a cushion 59 is provided between the second piston and the first piston.

It is a longitudinal sectional view of an air pressure reciprocating tool according to the present invention. It is a principal part longitudinal cross-sectional view of the reciprocating tool of FIG. The main part of another embodiment of an air pressure reciprocating tool according to the present invention is a vertical sectional side view showing. It is a vertical sectional side view showing still another embodiment of an air pressure reciprocating tool according to the present invention.

Explanation of symbols

Pneumatic reciprocating tool 10
Housing 12
Fixed shaft 14
First piston 18
The first tubular member 18a
The second tubular member 18b
O-ring 18c
First annular surface 18a-1
Second annular surface 18b-1
Second piston 20
Cylindrical wall 20a (cylindrical part)
Exhaust port 20b (second embodiment)
1st thru | or 4th exhaust port 20b-1-20b-4
Tool holding member 22
First biasing means (coil spring) 24
Second urging means (coil spring) 26
Rear end member 28
Compressed air introduction path 30
Compressed air supply path 32
Disc 34
Compression spring 36
Valve opening / closing operation section 38
Housing internal space 40
Exhaust passage 42
Exhaust port closing member 44
Through long hole 46
Connecting pin 50
Adjustment sleeve 52
Annular groove 53
O-ring 55
Cushion 59

Claims (6)

A tubular housing;
A fixed shaft extending forward from the rear end side of the housing in the housing;
A cylindrical first piston slidable along the fixed shaft;
A second piston provided in alignment with the first piston in the axial direction of the fixed shaft on the front end side of the first piston;
A tool holding member that is drivingly connected to the second piston and holds a tool on the front end side of the housing;
First urging means for urging the first piston forward;
Second urging means for urging the second piston backward;
A compressed air supply path for supplying compressed air between the first and second pistons through the fixed shaft;
Have
The first and second piston, slidably engaged with said axis direction, by the compressed air supplied therebetween, respectively, against the first and second biasing means, rear and Driven forward, it is arranged to exhaust the compressed air supplied between the first and second pistons to the outside of the housing when the first and second pistons are separated by a predetermined distance . An exhaust passage,
First piston, a first tubular member having an inner peripheral surface slidingly engages the outer circumferential surface of the fixed shaft, disposed in the second piston-side with respect to the first tubular member, is aligned with the first tubular member and the axial line direction, and a second tubular member which is displaceably set in the radial direction with respect to the fixed shaft,
Sliding engagement of the first and second pistons in the axial direction is performed between the second tubular member of the first piston and the second piston;
The first urging means urges the first tubular member and the second tubular member forward via the first tubular member,
A pneumatic reciprocating tool characterized in that the compressed air is configured to drive the second tubular member and the first tubular member backward via the second tubular member. The pneumatic reciprocating tool according to claim 1, further comprising a sealing ring that is set between the first and second cylindrical members and seals between them. First and second tubular member has first and second annular surfaces facing each other in the axial line direction, respectively, said sealing ring is clamped between the first and second annular surface The pneumatic reciprocating tool according to claim 2, wherein the pneumatic reciprocating tool is provided. A front and rear portions of the second tubular member of the first tubular member in the first piston is fitted in the axial line direction, said sealing ring, fitted radially opposed to each other The pneumatic reciprocating tool according to claim 2, wherein the pneumatic reciprocating tool is sandwiched between peripheral surfaces of the front portion and the rear portion. It said first piston second tubular member of has an inner peripheral surface of the larger diameter than the inner circumferential surface of the first tubular member, to the fixed shaft and coaxially around said fixed shaft The pneumatic reciprocating tool according to any one of claims 1 to 4, wherein the pneumatic reciprocating tool is set. Pneumatic according to any one of claims 1 to 4 said first piston second tubular member of is to extend forward from a position ahead of or front end position from the front end position of the fixed shaft Reciprocating tool.

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