JP4564456B2 - 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.

This type of pneumatic reciprocating tool includes, for example, a cylindrical housing, first and second pistons disposed in the housing so as to be displaceable in the axial direction of the housing, and extends forward from the second piston. A tool mounting member for attaching a tool such as a saw at the front end, compressed air supply passage means for communicating a compressed air source between the first and second pistons, and the first and second pistons facing forward and backward, respectively. First and second springs for biasing, supplying compressed air from the compressed air source between the first and second pistons to respectively connect the first and second pistons to the first and second pistons; There is a type in which the tool mounting member is driven forward by being displaced backward and forward against a spring. (See Patent Document 1)
JP-A-2005-205514

  However, in such a type of reciprocating tool, the weight of the second piston provided with the tool mounting member is large, and even when the second spring is used, a collision with the housing during forward drive occurs, so A cushioning material made of urethane rubber or the like is provided. However, when the pressure of compressed air for driving becomes high, such a cushioning material cannot maintain its durability.

  In view of these points, the present invention provides a pneumatic reciprocating tool that can properly brake and stop the second piston and relieve the impact force even when the compressed air for driving becomes high pressure. The purpose is to provide.

That is, the present invention
A tubular housing;
A first piston provided in the housing so as to be displaceable in an axial direction of the housing;
A second piston provided in the housing, arranged in alignment with the first piston in the axial direction, and displaceable in the axial direction;
A tool mounting member extending forward from the second piston and attaching a tool such as a saw to the front end;
Compressed air passage means for supplying a compressed air source between the first and second pistons, and supplying compressed air from the compressed air source between the first and second pistons. And a pneumatic reciprocating tool configured to drive the tool mounting member forward by displacing the second piston backward and forward, respectively.
A braking member provided in the housing at a front position of the second piston, including a piston braking chamber having an opening facing rearward, and driven and displaced forward by a predetermined distance by compressed air. A braking member that receives the front portion from the opening and brakes the second piston by the air in the piston braking chamber compressed by the front portion;
Atmospheric communication means for communicating the space between the first and second pistons to the atmosphere when the second piston enters the piston braking chamber;
A pneumatic reciprocating tool is provided.

  In this pneumatic reciprocating tool, since the braking is performed by the air compressed by the second piston in the piston braking chamber of the braking member, the durability of the cushioning material such as urethane rubber generated in the conventional tool is improved. The problem can be solved.

  Specifically, it is preferable to provide means for communicating a space between the second piston and the braking member in the housing with a compressed air source. In other words, since the air pressure in the piston braking chamber can be constantly increased by doing in this way, a large braking force is applied when the second piston is driven forward and enters the piston braking chamber. Can do.

  Moreover, it is preferable to provide a spring for urging the braking member rearward in the axial direction.

  That is, by doing in this way, since the braking force by the air in the piston braking chamber with respect to a 2nd piston can be made small, the said braking member can be made small.

  The brake member may be connected to the first piston so as to be displaced integrally with the first piston, and a spring for urging the first piston forward in the axial direction can be provided. That is, by doing so, the positions of the first piston and the braking member in the axial direction when the compressed air is not supplied between the first and second pistons are determined by the biasing force of the first and springs, When compressed air is supplied between the first and second pistons, the braking member is driven rearward together with the first piston. Therefore, when the second piston is driven forward by the compressed air, the second piston and the braking member approach each other, and when the second piston enters the piston braking chamber of the braking member, the rearward movement of the braking member. Therefore, the backward movement of the first piston is subjected to braking. Therefore, not only the impact relaxation of the second piston but also the impact relaxation of the first piston can be obtained. Further, the stroke length of the first and second pistons can be shortened.

More specifically,
The first piston has a rear end wall and a cylindrical wall extending forward from the rear end wall;
The second piston is slidable in the axial direction within the cylindrical wall of the first piston;
The atmosphere communicating means may have an opening provided so as to penetrate the cylindrical wall of the first piston, and a ventilation path provided in the housing and communicated with the opening to communicate with the atmosphere. .

Furthermore, in the above pneumatic reciprocating tools,
A fixed shaft extending forward in the housing from the rear end of the housing;
A rear end wall of the first piston has a hole through which the fixed shaft is inserted, and the first piston is slidable along the fixed shaft;
The compressed air supply passage means includes a through hole penetrating the fixed shaft in the axial direction, a compressed air introduction in which one end communicates with the rear end of the through hole and the other end communicates with the compressed air source. And a passage. The pneumatic reciprocating tool further includes a first end face communicated between the first and second pistons through the through hole, and a second end face having an area smaller than the first end face. The compressed air which is a valve and communicates with the rear end of the through hole of the fixed shaft when the force acting on the second end surface by compressed air is greater than the force acting on the first end surface by compressed air The compressed air that leads to the rear end of the through hole of the fixed shaft when the introduction passage is closed and the force acting on the second end surface by compressed air is smaller than the force acting on the first end surface by compressed air A valve that is displaced so as to open the introduction passage may be provided.

  By doing so, when the second piston is driven forward by the compressed air and displaced forward by a predetermined distance, the pressure between the first and second pistons is reduced to atmospheric pressure or a value close thereto by the atmospheric communication means. When this is done, the supply of compressed air between the first and second pistons is interrupted, and braking of the second piston can be efficiently stopped.

  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 and a cylindrical first provided in the housing so as to be displaceable in the axial direction of the housing. 1 piston 14, a second piston 16 provided in the first piston so as to be displaceable in the axial direction, and a tool mounting member 18 extending forward from the second piston and attaching a tool S such as a saw to the front end. And a compressed air supply means including a fixed shaft 20 that extends forward from the rear end of the housing 12 and is provided with a supply passage 19 for supplying compressed air between the first and second pistons.

  Compressed air from the compressed air source (not shown) is supplied between the first and second pistons 14 and 16 to displace the first and second pistons 14 and 16 backward and forward, respectively. Thus, the tool mounting member is driven forward.

  The pneumatic reciprocating tool 10 further includes a braking member 22 provided in the housing at a position in front of the second piston 16. The brake member 22 includes a piston brake chamber 24 having an opening facing rearward, and receives from the opening a small front portion 26 of the second piston 16 that is driven and displaced forward by a predetermined distance by compressed air. Thus, the braking of the second piston 16 is stopped by the air in the piston braking chamber 24 compressed by the front portion 26. In the illustrated example, a seal ring 27 is provided in the front portion 26 of the second piston 16, and the seal ring 27 seals the piston brake chamber 24 when the front portion 26 enters the piston brake chamber 24. ing. The first piston 14 has a rear end wall 28 and a cylindrical wall 30 extending forward from the rear end wall, and a through hole 32 is formed in the cylindrical wall 30. As shown in FIG. 3, when the front portion 26 of the second piston 16 enters the piston braking chamber 24 of the braking member 22, the through hole 32 is formed by the second piston 16. It is opened from the closed state, and the space between the first and second pistons 14 and 16 is vented to the atmosphere.

In the illustrated example, the braking member 22 is screwed to the first piston 14 and is displaced together with the first piston 14 in the axial direction. Further, the first piston 14 is biased forward by a first coil spring 34 set between the rear end portion of the housing 12 and the braking member 22 is set between the front end portion of the cylinder 12. The second coil spring 36 is biased backward.
As shown in FIG. 2, the compressed air supply means with which the supply path 19 of the fixed shaft 20 communicates includes a rear end wall 42 of the housing 12 and first and second rear ends attached to the rear end wall 42. It is composed of fluid passages formed in the members 44 and 46. In FIG. 2, reference numerals 45 and 47 denote packings.

  First, the second rear end member 46 is provided with a horizontal passage 48 to which the hose 40 is connected, and a valve setting hole which is provided so as to be orthogonal to the horizontal passage 48 and accommodates an on-off valve 50 which can be displaced in the vertical direction. 52 and an inverted L-shaped passage 54 provided near the lower end of the valve setting hole 52. The on-off valve 50 is urged to the closed position by a compression coil spring 53 set between the on-off valve 50 and the spring setting member 51 set in the valve setting hole 52, and is pivotally attached to the second rear end member 46. By pressing the lever 110 clockwise, it is moved to the open position.

  Next, the first rear end member 44 includes a first vertical passage 58 communicated with the inverted L-shaped passage 54, a small-diameter horizontal passage 59 connected to the upper end of the vertical passage 58, and the small-diameter horizontal passage 59. A large-diameter horizontal passage 60 connected to the vertical passage 58 at a lower position and a second vertical passage 62 described later are provided. FIG. 4 shows a left end view of the first rear end member taken along line IV-IV in FIG.

  The rear end wall 42 of the housing 12 has a horizontal through hole 66 having a diameter for receiving the circular rear end flange portion 64 of the fixed shaft 20 shown in FIG. 5, which is a cross-sectional view taken along the line VV in FIG. 3. have. A spool valve 68 and a valve holding member 70 for holding the spool valve slidably in the horizontal direction are set in the horizontal through hole. The spool valve 68 has a large-diameter sliding portion 72 and a small-diameter sliding portion 74, and correspondingly, the valve holding member 70 supports the large-diameter sliding portion 72 so as to be slidable. A central horizontal through hole having a large diameter hole 76 and a small diameter hole 78 is formed. The valve holding member 70 also has an upper horizontal through hole 80 at an upper portion thereof, and the right end of the horizontal through hole 80 is communicated with the small-diameter horizontal passage 59 of the first rear end member 44. On the left end surface of the valve holding member 70, a circular recess 82 is formed concentrically with the left end opening of the central horizontal through hole and having a larger diameter than the left end opening. The left end of the upper horizontal through hole 80 is the circular end. It communicates with the recess 82. The spool valve 68 has first and second recesses 84 and 86 formed from the left and right at the diametrical central portion thereof, and a radial hole 88 penetrating the spool valve in the radial direction is formed from the second recess 86. Has been. On the other hand, a passage 79 extending to a position communicating with the second vertical passage 62 of the first rear end member 44 is formed on the right side of the central horizontal through hole with respect to the small diameter hole portion 78. The passage 79 is in communication with the radial hole 88.

  As can be seen from the above, the spool valve 68 has a left-facing area larger than a right-facing area so that when the pressure of the compressed air source is applied to both faces, the spool valve 68 is moved to the right. It has become.

  The housing 12 is formed with a compressed air communication passage 90 extending in the axial direction along the lower portion as viewed in FIGS. 1 and 2, and the front end of the passage 90 is a first piston on the inner periphery of the housing 12. The second piston 16 and the brake member 22 through a radial through hole 94 formed in a liner 92 provided to slide 14 and a radial hole 96 formed in the cylindrical wall 30 of the first piston 14. It communicates with a space 98 between the two. As shown in the figure, annular sliding portions 100 and 102 are provided on both sides of the radial hole 96 provided in the cylindrical wall 30 of the first piston 14, and the compression entered from the radial through hole 94 provided in the liner 92. Air is prevented from leaking to both sides.

  Further, the through hole 32 provided in the cylindrical wall of the first piston 14 is formed between the liner 92 and the first piston and extends rearward, and as shown in FIG. 5, the flange portion 64 of the fixed shaft 20. And the rear end wall 42 of the housing 12 and communicated with the atmosphere by an exhaust passage 104 extending from the first rear end member 44.

  In order to operate the pneumatic reciprocating tool 10, the lever 110 is pushed clockwise as viewed in FIG. 1 to open the on-off valve 50. Thereby, the compressed air is applied from the compressed air source to the left and right side surfaces of the spool valve 68 through the hose 40, the passages 48 and 54 of the second rear end member 46, and the passages 58, 59 and 60 of the first rear end member 44. It is done. As described above, the left-facing surface of the spool valve 68 has a larger area than the right-facing surface. Therefore, when compressed air acts on these surfaces, the spool valve 68 is urged to the right and compressed. Air is supplied between the first and second pistons 14 and 16 through the through hole 19 of the fixed shaft 20. In the state shown in FIG. 1, the second piston 16 closes the through hole 32 formed in the cylindrical wall 30 of the first piston 14, so that the compressed air supplied between the first and second pistons is not The first and second pistons are driven backward and forward, respectively.

  FIG. 3 shows a state in which the first and second pistons 14 and 16 are so driven and the front end 26 of the second piston 16 starts to enter the right end opening of the piston braking chamber 24 of the braking member 22. ing. At this time, the second piston 16 opens the through hole 32 formed in the cylindrical wall 30 of the first piston 14, and communicates the space between the first and second pistons 14, 16 to the exhaust passage 104. For this reason, the first piston 14 is stopped by the action of the first coil spring 34 and then moved forward.

  However, the second piston 16 is inertial and continues to move forward at a greater speed than the brake member integral with the first piston 14, so that the front portion 26 of the second piston is further in the piston brake chamber of the brake member 22. 24, and compresses the air in the brake chamber (when the front portion 26 of the second piston enters the piston brake chamber 24, the spool valve is displaced to the left, and the upper horizontal passage 80 of the valve holding member 70). And the supply path 19 of the fixed shaft 20 are cut off). The air compressed in the brake chamber 24 brakes the second piston 16, and the second piston is finally stopped, and then the spool valve 68 is displaced to the left. The second piston 16 pushed back by the compressed air supplied to the space 98 through the compressed air communication passage 90, the radial through hole 94, and the radial hole 96 passes through the through hole 32 in the cylindrical wall 30 of the first piston 14. It closes and continues moving backward, and then the space 98 is communicated with the through hole 32 and the space 98 is communicated with the atmosphere. At the same time, the volume between the first and second pistons 14 and 16 is reduced and the internal air pressure rises, the spool valve 68 is moved to the right again, and the compressed air from the compressed air source passes through the fixed shaft 20. It is supplied between the first and second pistons through the hole 19.

  In this manner, the reciprocating operation of the pneumatic reciprocating tool is continued.

  When the on-off valve 50 is opened, the compressed air source is supplied to the passage 54 of the second rear end member 46, the passages 58 and 60 of the first rear end member 44, the radial hole 88 of the spool valve 68, and the second recess 86. Through the passage 79, the passage 62 of the first rear end member 44, and the passage 90 of the housing 12, the space 98 between the second piston 16 and the braking member 22 is always communicated. The air is filled with compressed air, and a large braking action can be performed on the second piston 16 when the second piston 16 enters the piston braking chamber 24.

  Further, when the on-off valve 50 is opened, the second piston 16 does not close the position shown in FIG. 3 with respect to the first piston 14, that is, the through hole 32 of the cylindrical wall 30 of the first piston 14. When the first and second pistons are in communication with the atmosphere in the state, the compressed air is supplied to the space 24 between the second piston 16 and the braking member 22 as described above. Therefore, the second piston 16 is brought into a state as shown in FIG. 1 with respect to the first piston 14 by the action of the compressed air, and the spool valve 68 is moved to the right. The reciprocating tool is used for reciprocating motion.

  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. For example, in the illustrated example, the braking member 22 is separated from the housing 12 and is slid within the housing. However, the braking member 22 may be integrally formed with the housing and fixed to the housing. it can.

It is a longitudinal cross-sectional view of the compression-pneumatic reciprocating tool which concerns on this invention, and shows the state which is not act | operated. It is an expanded sectional view which shows the compressed air supply path | route of the compression-pneumatic reciprocating tool of FIG. FIG. 2 is a view similar to FIG. 1, but shows a state where the compressed pneumatic reciprocating tool is operated and the tip of the second piston starts to enter the piston braking chamber of the braking member. It is the figure seen along the IV-IV line in FIG. It is sectional drawing seen along the VV line in FIG. FIG. 2 is a view similar to FIG. 1, but shows a state where the compressed pneumatic reciprocating tool is operated and the second piston enters the piston braking chamber of the braking member and is stopped.

Explanation of symbols

Pneumatic reciprocating tool 10; housing 12; first piston 14; second piston 16; tool mounting member 18; supply passage (through hole) 19; fixed shaft 20; braking member 22; piston braking chamber 24; Seal ring 27; Rear end wall 28; Cylindrical wall 30; Through-hole 32; First coil spring 34; Second coil spring 36; Hose 40; Rear end wall 42; First rear end member 44; Horizontal passage 48; Open / close valve 50; Spring setting member 51; Valve setting hole 52; Compression coil spring 53; Reverse L-shaped passage 54; First vertical passage 58; Small diameter horizontal passage 59; Large diameter horizontal passage 60; Second vertical passage 62: rear end flange portion 64; horizontal through hole 66; spool valve 68; valve holding member 70; large-diameter sliding portion 72; small-diameter sliding portion 74 Large-diameter hole 76; small-diameter hole 78; passage 79; upper horizontal through-hole 80; circular recess 82; first recess 84; second recess 86; radial hole 88; Radial through hole 96; space 98; annular sliding portion 100; exhaust passage 104; lever 110

Claims (6)

A tubular housing;
A first piston provided in the housing so as to be displaceable in an axial direction of the housing;
A second piston provided in the housing, arranged in alignment with the first piston in the axial direction, and displaceable in the axial direction;
A tool mounting member extending forward from the second piston and attaching a tool such as a saw to the front end;
Compressed air supply means for supplying compressed air from a compressed air source between the first and second pistons, and compressed air is supplied between the first and second pistons by the compressed air supply means. In the pneumatic reciprocating tool configured to drive the tool mounting member forward by displacing the first and second pistons backward and forward, respectively.
A brake member provided in the housing at a front position of the second piston, comprising a piston brake chamber having an opening facing rearward, and driven and displaced forward by a predetermined distance by compressed air. A braking member that receives the front portion from the opening and brakes the second piston with air in the piston braking chamber compressed by the front portion;
Atmospheric communication means for communicating the space between the first and second pistons to the atmosphere when the second piston enters the piston braking chamber;
A pneumatic reciprocating tool characterized by comprising:   The pneumatic reciprocating tool according to claim 1, further comprising means for communicating a space between the second piston and the braking member in the housing with a compressed air source.   The pneumatic reciprocating tool according to claim 1, further comprising a spring that biases the braking member rearward in the axial direction. The braking member is connected to the first piston and is integrally displaced with the first piston;
The pneumatic reciprocating tool according to any one of claims 1 to 3, further comprising a spring that biases the first piston forward in the axial direction. The first piston has a rear end wall and a cylindrical wall extending forward from the rear end wall;
The second piston is slidable in the axial direction within the cylindrical wall of the first piston;
The atmosphere communication means has an opening provided so as to penetrate the cylindrical wall of the first piston, and a ventilation path provided in the housing and communicated with the opening and communicating with the atmosphere. Item 5. A pneumatic reciprocating tool according to any one of Items 1 to 4. A fixed shaft extending forward in the housing from the rear end of the housing;
A rear end wall of the first piston has a hole through which the fixed shaft is inserted, and the first piston is slidable along the fixed shaft;
The compressed air supply means includes a through-hole penetrating the fixed shaft in the axial direction, a compressed air introduction passage having one end communicating with the rear end of the through-hole and the other end communicating with the compressed air source. And
The pneumatic reciprocating tool further includes a first end surface communicated between the first and second pistons through the through hole of the fixed shaft, and a second end surface having a smaller area than the first end surface. And when the force acting on the second end surface by the compressed air is larger than the force acting on the first end surface by the compressed air, the valve leads to the rear end portion of the through hole of the fixed shaft. The compressed air introduction passage is closed, and when the force acting on the second end surface by compressed air is smaller than the force acting on the first end surface compressed air, the fixed shaft is led to the rear end portion of the through hole. The pneumatic reciprocating tool according to claim 5, further comprising a valve that is displaced so as to open the compressed air introduction passage.

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