JP4671608B2 - 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 pneumatic reciprocating tools of this type have been developed. (For example, see Patent Document 1 and Patent Document 2)
However, these conventional tools have problems such as a complicated structure, relatively heavy weight, and large air consumption. In addition, the compressed air is not smoothly supplied and exhausted, which may hinder the operation of the tool.
4-2781 US Patent 5,755,292

  In view of the above-described points, an object of the present invention is to provide a pneumatic reciprocating tool that has a simple structure, is small in weight, and can smoothly supply and exhaust air.

That is, the present invention
A tubular housing;
A front end member for closing the front end of the housing;
A rear end member for closing the rear end of the housing;
A fixed shaft extending axially forward of the housing from the closed rear end of the housing;
A first piston having a hole through which the fixed shaft is inserted and slidable along the fixed shaft;
A second piston provided on the front end side of the first piston;
A tool attachment member that passes through the front end member from the second piston, extends forward in the axial direction, and attaches a tool such as a saw to the front end;
First biasing means for biasing the first piston forward;
Second urging means for urging the second piston backward;
A compressed air supply path for supplying compressed air from the rear end member through the fixed shaft and between the first and second pistons;
The first and second pistons are driven backward and forward by the compressed air supplied between them, against the first and second urging means, respectively, and the first and second pistons are predetermined. An exhaust passage for exhausting the compressed air supplied between the first and second pistons to the outside of the housing when separated by an interval;
A piston drive position in which the first and second pistons are separated from each other by supplying compressed air between them, and a tool attached to a tool attachment member is in a forward position, and the exhaust passage Compressed air is exhausted through and moved close to each other and moved to a piston return position where the tool is in a retracted position.
A pneumatic reciprocating tool is provided.

  This pneumatic reciprocating tool is easier to use as a hand-held tool because its structure is simpler, the air supply / exhaust can be performed stably, and the weight can be reduced compared to the conventional tool described above. It will be a thing.

In particular,
The compressed air supply path is
An axial portion extending in the fixed shaft toward the front end;
A radial portion extending radially from the axial portion and opening in a side surface of the fixed shaft;
A compressed air inlet recess for opening the inner wall of the hole through which the fixed shaft of the first piston is inserted and receiving compressed air;
A compressed air introduction path communicated with the compressed air inlet recess and for introducing compressed air between the first and second pistons;
Have
When the first and second pistons are at the piston return positions, the compressed air inlet recess is communicated with the radial portion, and compressed air passes through the compressed air introduction path to the first and second pistons. Supplied during and
The first and second pistons are moved toward the piston drive position, and before reaching the piston drive position, the compressed air inlet recess is cut off from the radial portion and between the first and second pistons. And the compressed air supplied between the first and second pistons is exhausted from the exhaust passage to the outside of the housing.

  The compressed air introduction path can be provided so as to extend forward in the first piston from the compressed air inlet recess, but is provided on the fixed shaft so that the first piston is directed from the return position to the drive position. It is also possible to communicate with the compressed air inlet recess within a predetermined range of movement.

  More specifically, the second piston includes a cylindrical portion having an outer peripheral surface that slides with an outer peripheral surface of the first piston, and the first and second pistons are provided in the cylindrical portion. An exhaust path that allows the compressed air supplied between the first and second pistons to be exhausted while being driven toward the piston drive position may be provided.

As another specific example,
The fixed shaft passes through the first piston;
The second piston has a hole for slidably receiving a front end portion of the fixed shaft;
The compressed air supply path is
An axial portion extending through the fixed shaft to the front end portion;
A compressed air inlet recess for opening the inner wall of the hole for receiving the fixed shaft of the second piston and receiving compressed air;
A compressed air introduction path communicated with the compressed air inlet recess and for introducing compressed air between the first and second pistons;
Have
When the first and second pistons are at the piston return positions, the compressed air inlet recess is communicated with the compressed air supply path, and compressed air passes through the compressed air introduction path to the first and second. Supplied between pistons,
The first and second pistons are moved toward the piston drive position, and before reaching the piston drive position, the compressed air inlet recess is cut off from the axial portion and between the first and second pistons. The supply of compressed air is cut off, and the compressed air supplied between the first and second pistons is exhausted from the exhaust passage to the outside of the housing.

  The compressed air inlet recess is not necessarily provided on the peripheral wall of the hole, and can be provided as an extension of the front end of the hole.

In this case, the compressed air introduction path is
A radial portion extending radially from the axial portion and opening in a side surface of the fixed shaft; and
It can be provided so as to extend backward in the second piston from the compressed air inlet recess.

  The compressed air introduction path is provided in the fixed shaft so that the second piston communicates with the compressed air inlet recess in a predetermined range of movement from the return position to the drive position. be able to.

  Specifically, the first piston includes a cylindrical portion having an inner peripheral surface that slides with an outer peripheral surface of the second piston, and the first and second pistons are disposed on the cylindrical portion. In the middle of being driven toward the drive position, an exhaust path that allows the compressed air supplied between the first and second pistons to be exhausted may be provided.

As another specific example,
The compressed air supply path is
The inside of the fixed shaft extends in the axial direction and opens at the front end of the fixed shaft,
The second piston has an opening opening / closing member extending from a rear end of the piston and extending through an opening of the compressed air supply path provided at a front end of the fixed shaft;
When the first and second pistons are at the piston return position, compressed air is supplied between the first and second pistons through the opening of the compressed air supply path,
The first and second pistons are moved toward the piston driving position, and before reaching the piston driving position, the opening of the compressed air supply passage is blocked by the opening opening / closing member, and the first and second pistons The supply of compressed air between the first and second pistons may be interrupted, and the compressed air supplied between the first and second pistons may be exhausted from the exhaust path to the outside of the housing. .

In the reciprocating tool as described above,
An urging force adjusting member screw-engaged around the fixed shaft;
The first urging means is a coil spring set between the urging force adjusting member and the first piston around the fixed shaft;
By rotating the urging force adjusting member on the fixed shaft, the axial position on the fixed shaft can be adjusted, and the urging force of the first urging means on the first piston can be adjusted. It can also be.

  DESCRIPTION OF EMBODIMENTS Hereinafter, embodiments of a pneumatic reciprocating tool according to the present invention will be described in detail with reference to the accompanying drawings.

  As shown in FIGS. 1 and 2, a pneumatic reciprocating tool 10 according to the present invention includes a cylindrical housing 12, a front end member 14 that closes the front end of the housing, and a rear end that closes the rear end of the housing. An end member 16, a fixed shaft 18 extending forward in the axial direction of the housing from the closed rear end of the housing, a first piston 20 slidably provided along the fixed shaft 18, and the first A second piston 22 provided on the front end side of the piston 20; a tool attachment member 24 that passes through the front end member 14 from the second piston 22 and extends forward in the axial direction and attaches a tool T (such as a saw) to the front end; The first spring 26 for urging the first piston 20 forward, the second spring 28 for urging the second piston 22 rearward, and the first and second pistons from the rear end member 16 through the fixed shaft 18. Compressed air supply path 30 for supplying compressed air between the cylinders 20 and 22, a valve 32 for opening and closing the compressed air supply path 30, and compressed air supplied between the first and second pistons 20 and 22 Therefore, when the first and second pistons 20 and 22 are separated from each other by a predetermined distance, the first and second pistons 26 and 22 are driven against the first and second springs 26 and 28, respectively. And an exhaust passage 34 for exhausting the compressed air supplied between the second pistons 20 and 22 to the outside of the housing 12.

  The first and second pistons 20 and 22 are separated from each other by the compressed air supplied therebetween, and the piston driving position in which the tool T attached to the second piston 22 is in a predetermined forward position. (FIG. 2) and the piston return position where the compressed air is exhausted through the exhaust passage 34 and is brought close to each other by the first and second springs 26 and 28 so that the tool T is in the retracted position. It is supposed to be movable. (FIG. 1 shows a state in which the compressed air reciprocating tool 10 is not operated, that is, a state in which no compressed air is present, and the first and second pistons 20 and 22 are in contact with each other in the axial direction. However, in the piston return position during the operation of the compressed air reciprocating tool 10, some compressed air remains between the first and second pistons 20 and 22, so that they are directly (Does not come into contact.)

  The compressed air supply passage 30 has an axial portion 36 extending toward the front end in the fixed shaft 18, and a radial portion 38 that extends radially from the tip portion of the axial portion 36 and opens to the side surface of the fixed shaft 18. And a compressed air introduction path 40 extending from the rear end side to the front end in the first piston 20. When the first and second pistons 20 and 22 are in the piston return position, the compressed air introduction passage 40 is communicated with the radial portion 38 so as to supply compressed air between the first and second pistons 20 and 22. It has become. Further, in the stroke in which the first and second pistons 20 and 22 are moved toward the piston drive position (FIG. 2), the compressed air introduction path 40 has a radial portion before reaching the piston drive position (FIG. 2). The supply of compressed air between the first and second pistons 20 and 22 is cut off from the valve 38. As will be described later, at this time, the compressed air supplied between the first and second pistons 20 and 22 is exhausted from the exhaust passage 34 to the outside of the housing 12.

  In the illustrated example, the first piston 20 has a through hole 42 through which the fixed shaft 18 is inserted, and a compressed air inlet recess formed in an annular shape so as to open to the inner wall surface of the through hole and surround the through hole. 44, and a plurality of the compressed air introduction passages 40 are formed so as to extend in the axial direction from the compressed air inlet recess 44 in the first piston 20 (in the drawing, two compressed air introduction passages 40 are formed. 3 is provided at a predetermined interval in the circumferential direction).

In the illustrated example, the second piston 22 has an outer peripheral surface 22-1 having a space with the inner wall surface of the housing 12 and an inner peripheral surface 22-2 that slides with the outer peripheral surface of the first piston 20. It has a cylindrical portion 22-3 and a disk-shaped portion 22-4 that closes the end of the cylindrical portion and faces the first piston. A plurality of notches 22-6 as exhaust passages extending forward from the rear end edge 22-5 of the cylindrical portion are formed in the cylindrical portion at appropriate intervals in the circumferential direction (only two are shown in the drawing). In the middle of driving the first and second pistons 20 and 22 toward the piston drive position (FIG. 2), the compressed air supplied between the first and second pistons 20 and 22 is notched 22−. 6 through the exhaust passage 34. Instead of the notch 22-6, a plurality of grooves or holes may be formed on the inner peripheral surface. An extension portion 22-7 extending forward from the center of the front end surface of the disk-like portion 22-4 is formed, and a tool mounting member 46 is fixed to the front end of the extension portion, and the tool T is attached to the tip of the extension portion 22-7. The fixing member 48 for fixing the is attached. In the figure, 50 is a screw for fixing the rear end of the tool T to the fixing member 48, 52 is set on both sides of the tool T to protect the attachment base end portion of the saw (formed by bending a metal wire) The protective member is shown. These are widely known and will not be described in detail.

  The rear end member 16 extends into the housing by closing the rear end opening of the housing 12, and an air supply member 56 is fixed to the rear end surface of the rear end member 16 via a packing 54. The supply member extends in the axial direction from an air supply port 30-1 communicating with a compressed air source (air compressor) (not shown), and extends through the valve 32 to the front end surface of the air supply member 56. 2, and the air supply passage portion communicates with a recess 30-4 formed in the rear end member 16 through a through hole 30-3 formed in the packing 54, and the recess 30-4 is fixed. The shaft 18 communicates with an axial portion 36, and the axial portion 36, the radial portion 38, the compressed air introduction passage 40, and the compressed air inlet recess 44 form a compressed air supply passage 30. A valve operating lever 60 is pivotally attached to the air supply member 56. A stopper 62 pivotally attached to the operating lever and biased by a spring is rotated clockwise from the position shown in FIG. By pivoting the lever 60 in the clockwise direction, the valve 32 is pushed up to open the compressed air supply path 30.

  As shown in the drawing, a male screw 18-1 is formed on the outer peripheral surface of the fixed shaft 18, and a nut-like spring adjusting member 64 is screwed to the male screw. The spring adjusting member 64 is displaced in the axial direction by being rotated on the fixed shaft 18, and the first piston 20 of the first spring 26 set between the spring adjusting member 64 and the first piston 20. The spring force against is adjusted. As shown in FIG. 3, the spring adjustment member 64 is meshed with an adjustment gear 66 rotatably attached to the housing, and is adjusted by rotating the adjustment gear 66. . By this adjustment, the back and forth reciprocation distance of the second piston can be varied, and the stroke length of the tool T can be adjusted.

  In order to operate the compressed air reciprocating tool 10, the valve operating lever 60 is rotated clockwise as described above, the valve 32 is pushed up, and the first and second pistons are connected via the compressed air supply path 30. Compressed air is supplied between 20 and 22. The first and second pistons 20 and 22 are instantaneously driven backward and forward by the compressed air, and are separated from each other. In this case, the spring force of the second spring 28 is set to be smaller than that of the first spring 26 so that the second piston 22 is driven forward largely compared to the first piston 20. When the first and second pistons 20 and 22 move away from the position shown in FIG. 1 toward the piston driving position shown in FIG. 2, the front end edge 20-1 of the first piston is formed on the second piston 22. The compressed air supplied between the first and second pistons is exhausted from the exhaust passage 34 to the outside of the reciprocating tool through the notch 22-6. The At substantially the same time, the radial portion 38 of the compressed air supply passage 30 of the fixed shaft 18 is closed by the inner peripheral surface of the first piston 20 and communicates with the compressed air inlet recess 44 formed in the first piston 20. Is cut off and the supply of compressed air is stopped. Even if it becomes such a state, the 1st and 2nd move to back and front, respectively by inertia, but after reaching the piston drive position shown in FIG. 2, by the 1st and 2nd springs 26 and 28, respectively. Are pushed back forward and backward, respectively. The compressed air inlet recess 44 of the pushed first piston and the radial portion 38 of the shaft 18 communicate with each other again, and the first and second pistons are driven rearward and forward, and the tool T repeats reciprocation.

  Although the embodiments of the present invention have been described above, the present invention is not limited to these embodiments, and various modifications can be made within the scope of the present invention defined in the claims.

It is a longitudinal cross-sectional view of the compressed air type reciprocating tool which concerns on this invention, and shows the state which is not act | operated. FIG. 2 is a view similar to FIG. 1, but shows a state where the compressed air reciprocating tool is actuated to drive a tool such as a saw attached to the tip to the most front end position. FIG. 3 is a cross-sectional view taken along line III-III in FIG. 1 and shows a mechanism for adjusting a first spring in a compressed air reciprocating tool.

Explanation of symbols

DESCRIPTION OF SYMBOLS 10 Compressed-air reciprocating tool 12 Housing 14 Front end member 16 Rear end member 18 Fixed shaft 20 1st piston 20-1 Front end edge 22 of 1st piston 2nd piston 22-1 Outer peripheral surface 22-2 Inner peripheral surface 22-3 Cylindrical portion 22-4 Disc-shaped portion 22-5 Rear edge 22-6 Notch 22-7 Extension portion 24 Tool mounting member 26 First spring (first biasing means)
28 Second spring (second biasing means)
30 Compressed air supply path 30-1 Supply port 30-2 Supply path part 30-3 Through hole 30-4 Recess 32 Valve 34 Exhaust path 36 Axial direction part 38 Radial part 40 Compressed air introduction path 42 Through hole 44 Compressed air Entrance recess 46 Tool mounting member 48 Fixing member 50 Screw 52 (Saw) protection member 54 Packing 56 Air supply member 60 Valve operation lever 62 Stopper 64 Spring adjustment member 66 Adjustment gear

Claims (9)

A tubular housing;
A fixed shaft extending axially forward of the housing from the rear end of the housing;
A first piston having a hole through which the fixed shaft is inserted and slidable along the fixed shaft in the housing ;
A second piston provided on the front end side of the first piston in the housing ;
A tool mounting member that passes through the front end of the housing from the second piston and extends forward in the axial direction, and a tool such as a saw is attached to the front end;
First biasing means for biasing 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 ;
The first and second pistons are driven backward and forward by the compressed air supplied between them, against the first and second urging means, respectively, and the first and second pistons are predetermined. An exhaust passage for exhausting the compressed air supplied between the first and second pistons to the outside of the housing when separated by an interval;
A piston drive position in which the first and second pistons are separated from each other by supplying compressed air between them, and a tool attached to a tool attachment member is in a forward position, and the exhaust passage A pneumatic reciprocating tool which is movable between a piston return position in which the compressed air is exhausted through and close to each other so that the tool is in a retracted position ;
The compressed air supply path is
An axial portion extending in the fixed shaft toward the front end;
A radial portion extending radially from the axial portion and opening in a side surface of the fixed shaft;
A compressed air inlet recess for opening the inner wall of the hole through which the fixed shaft of the first piston is inserted and receiving compressed air;
A compressed air introduction path communicated with the compressed air inlet recess and for introducing compressed air between the first and second pistons;
Have
When the first and second pistons are at the piston return positions, the compressed air inlet recess is communicated with the radial portion, and compressed air passes through the compressed air introduction path to the first and second pistons. Supplied during and
The first and second pistons are moved toward the piston drive position, and before reaching the piston drive position, the compressed air inlet recess is cut off from the radial portion and between the first and second pistons. And the compressed air supplied between the first and second pistons is exhausted from the exhaust passage to the outside of the housing. Reciprocating tool. The compressed air introduction passage, an air pressure reciprocating tool according to claim 1, characterized in that is provided so as to extend within the first piston forwardly from the compressed air inlet recess. The compressed air introduction path is provided in the fixed shaft, and the first piston communicates with the compressed air inlet recess in a predetermined range of movement from the return position to the drive position. air pressure reciprocating tool according to claim 1, characterized in that there. The second piston includes a cylindrical portion having an outer peripheral surface that slides with an outer peripheral surface of the first piston, and the first and second pistons are directed toward the piston driving position in the cylindrical portion. middle driven Te in, according to any one of claims 1 to 3, characterized in that the exhaust passage compressed air supplied between said first and second pistons to be exhausted is provided Pneumatic reciprocating tool. A tubular housing;
A fixed shaft extending axially forward of the housing from the rear end of the housing;
A first piston having a hole through which the fixed shaft is inserted and slidable along the fixed shaft in the housing;
A second piston provided on the front end side of the first piston in the housing;
A tool mounting member that passes through the front end of the second piston or the housing and extends forward in the axial direction, and a tool such as a saw is attached to the front end;
First biasing means for biasing 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;
The first and second pistons are driven backward and forward by the compressed air supplied between them, against the first and second urging means, respectively, and the first and second pistons are predetermined. An exhaust passage for exhausting the compressed air supplied between the first and second pistons to the outside of the housing when separated by an interval;
Have
A piston drive position in which the first and second pistons are separated from each other by supplying compressed air between them, and a tool attached to a tool attachment member is in a forward position, and the exhaust passage A pneumatic reciprocating tool which is movable between a piston return position in which the compressed air is exhausted through and close to each other so that the tool is in a retracted position;
The fixed shaft passes through the first piston;
The second piston has a hole for slidably receiving a front end portion of the fixed shaft;
The compressed air supply path is
An axial portion extending through the fixed shaft to the front end portion;
A radial portion extending radially from the axial portion and opening in a side surface of the fixed shaft;
A compressed air inlet recess for opening the inner wall of the hole for receiving the fixed shaft of the second piston and receiving compressed air;
A compressed air introduction path communicated with the compressed air inlet recess and for introducing compressed air between the first and second pistons;
Have
When the first and second pistons are at the piston return positions, the compressed air inlet recess is communicated with the radial portion, and compressed air passes through the compressed air introduction path to the first and second pistons. Supplied during and
The first and second pistons are moved toward the piston drive position, and before reaching the piston drive position, the compressed air inlet recess is cut off from the radial portion and between the first and second pistons. the supply is cut off the compressed air, pneumatic that the compressed air supplied between the first and second piston is characterized in that it is adapted to be exhausted to the outside of the housing from the exhaust passage Reciprocating tool. The compressed air introduction passage, an air pressure reciprocating tool according to claim 5, characterized in that is provided so as to extend the second inner piston rearwardly from the compressed air inlet recess. The compressed air introduction path is provided in the fixed shaft, and the second piston is communicated with the compressed air inlet recess in a predetermined range of movement from the return position to the drive position. air pressure reciprocating tool according to claim 5, characterized in that there. The first piston includes a cylindrical portion having an inner peripheral surface that slides with an outer peripheral surface of the second piston, and the first and second pistons are directed toward the piston driving position in the cylindrical portion. 8. The exhaust passage according to claim 5 , wherein an exhaust passage is provided so that the compressed air supplied between the first and second pistons is exhausted during driving. Pneumatic reciprocating tool. An urging force adjusting member screw-engaged around the fixed shaft;
The first urging means is a coil spring set between the urging force adjusting member and the first piston around the fixed shaft;
By rotating the urging force adjusting member on the fixed shaft, the axial position on the fixed shaft is adjusted, and the urging force of the first urging means with respect to the first piston is adjusted. A pneumatic reciprocating tool according to any one of claims 1 to 8 .

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