JP2008000871A - Driving machine - Google Patents

Abstract

A driving machine capable of improving the durability of a driver blade and a piston.
A piston 11 that reciprocates in a cylinder and a driver blade 12 that reciprocates together with the piston 11 to hit a stopper, and one end of the driver blade 12 is formed in a slit 11a formed in the piston 11. In the driving machine in which one end of the driver blade 12 is connected to the piston 11 by a piston pin 13 which is fitted and inserted into holes 12a and 11b formed in the driver blade 12 and the piston 11, respectively. A slope portion 13b is formed on the outer peripheral portion of the piston pin 13 from the intermediate portion in the axial direction of the piston pin 13 to the insertion-side end surface 13a, and the axial length x of the slope portion 13b is a slit 11a formed in the piston 11. Is set to be larger than the width b (x> b).
[Selection] Figure 2

Description

  The present invention relates to a driving machine for driving a stopper such as a nail or a staple by a driver blade that reciprocates with a piston.

  In a driving machine for driving a stopper such as a nail or a staple by a driver blade that reciprocates with a piston, a plate-like driver blade 112 has a slit formed at one end of the piston 111 as shown in FIG. The piston 111 is fitted to the piston 111 and is connected to the piston 111 by press-fitting into the piston 111 (see, for example, Patent Documents 1 and 2).

  Here, a process of connecting the driver blade 112 to the piston 111 by the piston pin 113 will be described with reference to FIGS. 8 to 11 are sectional views showing a method of connecting the driver blade to the piston in the order of the steps.

  As shown in FIG. 8, a slit 111a that passes through the center of the shaft is provided in the lower portion of the piston 111 in a direction perpendicular to the paper surface of FIG. 8, and a circular hole 111b that passes through the slit 111a is axial with respect to the slit 111a. It penetrates in the perpendicular direction (lateral direction of FIG. 8). Further, a circular hole 112 a having the same diameter as the circular hole 111 b formed in the piston 111 is penetrated at the end of the driver blade 112.

  Thus, in order to connect the driver blade 112 to the piston 111, one end of the driver blade 112 is fitted into the slit 111a of the piston 111 as shown in FIG. At this time, since the center of the circular hole 111b of the piston 111 and the center of the circular hole 112a of the driver blade 112 are shifted within the range of intersection, when one end of the driver blade 112 is fitted into the slit 111a of the piston 111, Steps A and B as shown are inevitably formed between the hole 111b and the circular hole 112a of the driver blade 112.

  In the above state, when the piston pin 113 is inserted into the circular hole 111b of the piston 111 as shown in FIG. 8, the insertion side end surface 113a of the piston pin 113 first comes into contact with the stepped portion A. It tilts in the circular hole 111b. That is, the piston pin 113 is inclined so that its insertion side end surface 113a faces downward in FIG. Then, when this inclined piston pin 113 is forcibly inserted into the circular hole 112a of the driver blade 112 and the circular hole 111b of the piston pin 111 as it is, the insertion side end 113a of the piston pin 113 is as shown in FIG. Contact with the step B.

After that, when the piston pin 113 is further pushed in, the piston pin 113 is press-fitted into the piston 111 while being inclined as shown in FIG. The driver blade 112 is connected to the piston 111 while being scraped off or the outer peripheral surfaces of the driver blade 112 and the piston pin 111 are scratched and scratched.
JP 58-090475 A Japanese Patent Application Laid-Open No. 60-062471

  When a driving operation such as a nail is performed by a driver blade 112 connected to the piston 111 by a tilted piston pin 113 as shown in FIG. 11, the piston 111 collides with a piston bumper (not shown) at the time of driving, and inertia When force is generated, stress concentration occurs in the scratches generated in the inner surface of the circular hole 111b of the piston 111 and the scratches generated in the circular hole 112a of the driver blade 112, thereby damaging the driver blade 112 and the piston 111. There was a possibility.

  The present invention has been made in view of the above problems, and the object of the present invention is to improve the durability of the driver blade and the piston by preventing the concentration of stress at the connecting portion of the driver blade to the piston by the piston pin. The object is to provide a driving machine that can be realized.

  In order to achieve the above object, an invention according to claim 1 is provided with a piston that reciprocates in a cylinder, and a driver blade that reciprocates with the piston and strikes a stopper, and one end of the driver blade is attached to the piston. In a driving machine in which one end of a driver blade is connected to a piston by a piston pin that is fitted into a formed slit and press-fitted into a hole formed in each of the driver blade and the piston. In addition, a slope portion extending from the axial intermediate portion of the piston pin to the insertion side end face is formed, and the axial length of the slope portion is set larger than the width of the slit formed in the piston. To do.

  According to a second aspect of the present invention, in the first aspect of the invention, the inclined surface portion is a tapered surface inclined toward the axial center toward the insertion side end surface of the piston pin, and is formed in the slit of the piston of the driver blade. The distance from the end face on the mating side to the center of the hole is set to be larger than the distance from the end face of the slit of the piston to the center of the hole, and when the driver blade is statically inserted into the piston slit, The center of the hole is eccentric to the slit entrance side of the piston with respect to the center of the piston hole.

  According to the first aspect of the present invention, since the slope portion is formed on the outer peripheral portion of the piston pin and the length thereof is larger than the width of the slit of the piston, there is a step between the hole of the piston and the hole of the driver blade. Even if there is a part, the insertion side end of the piston pin is received by the piston hole before the insertion side end surface of the piston pin comes into contact with the step part and tilts. Is avoided by the slope portion formed on the piston pin, and the piston pin is smoothly pressed into the holes of the piston and the driver blade without being inclined to connect the driver blade to the piston. For this reason, even when the piston collides with the piston bumper during driving and an inertial force is generated, stress concentration does not occur in the connecting portion of the driver blade to the piston, and the driver blade and the piston are damaged. They are prevented and their durability is increased.

  According to the second aspect of the present invention, in the process of inserting the piston pin into the hole of the piston and the driver blade, the driver blade is slit in the slit of the piston by the wedge action by the tapered inclined portion formed in the piston pin. Since it moves to the end face side (anti-slit inlet side) and the end face is pressed against the slit end face of the piston, the collision load at the time of driving is received by the slit end face of the piston. For this reason, the load which a driver blade and a piston pin receive is reduced, and the durability improvement of a driver blade and a piston pin is achieved further.

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

  FIG. 1 is a cutaway side view of a pneumatic nailing machine 1 as one embodiment of a driving machine according to the present invention. The illustrated nailing machine 1 includes a body 2 having a substantially T shape in a side view. The exhaust cover 3 is airtightly attached to the upper end opening of the body 2. An accumulator chamber S1 is formed in the body 2, and an air plug 4 for connecting an air hose (not shown) is provided at the rear end of the handle portion 2a of the body 2.

  Further, the body 2 is provided with a trigger valve 9 including a plunger 8 that can accommodate a large number of nails 5 and that is moved up and down by a trigger 7.

  A cylinder 10 is provided in the body 2, and a piston 11 is fitted into the cylinder 10 so as to be slidable up and down. One end of a plate-like driver blade 12 is connected to the piston 11 by a piston pin 13, and the driver blade 12 extends vertically downward in the cylinder 10. The cylinder 10 is divided into a piston upper chamber S2 and a piston lower chamber S3 by a piston 11, and a piston bumper 14 made of an elastic body such as rubber is provided at the bottom of the cylinder 10.

  Furthermore, a cylindrical return air chamber S4 defined by a partition wall 15 is formed in the lower half of the body 2 between the cylinder 10 and constitutes a part of the return air chamber S4 of the cylinder 10. A plurality of air holes 16 and 17 are formed in the circumferential direction above and below the portion, and only the flow of compressed air from the piston upper chamber S2 toward the return air chamber S4 is allowed in the upper air hole 16. A check valve 18 is provided.

  On the other hand, a main valve 19 that contacts and separates from the upper surface of the cylinder 10 is provided in the exhaust cover 3 so as to be vertically slidable. The direction is in close contact with the upper end surface). A main valve chamber S5 is defined between the main valve 19 and the exhaust cover 3, and the main valve chamber S5 communicates with the trigger valve 9 via an air passage 21, which will be described later. As described above, the pressure accumulation chamber S1 or the atmosphere is selectively communicated by the trigger valve 9. The exhaust cover 3 is formed with an exhaust hole 22 that opens into the atmosphere. The exhaust hole 22 is opened and closed by the main valve 19 and selectively communicated with the cylinder upper chamber S2.

  Further, a nose 23 for guiding the nail 5 is attached to the distal end portion of the body 2, and a push lever 24 that can move in the vertical direction along the nose 23 is provided. An injection port 25 for driving the nails 5 supplied from the magazine 6 one by one is formed. The push lever 24 is connected to the arm plate 26 of the trigger 7.

  Next, the operation of the nailing machine 1 having the above configuration will be described.

  When an air hose (not shown) is connected to the air plug 4 at the time of nailing the workpiece W such as wood shown in the figure, compressed air is supplied from a pressure supply source (not shown) such as a compressor through the air hose to the body of the nailing machine 1. 2 is supplied to and accumulated in the pressure accumulating chamber S <b> 1 and a part thereof flows into the main valve chamber S <b> 5 through the air passage 21.

  The compressed air that has flowed into the main valve chamber S5 causes the main valve 19 to be brought into close contact with the upper end surface of the cylinder 10 together with the spring 20 as shown in FIG. In order to cut off the communication and prevent the compressed air in the pressure accumulating chamber S1 from flowing into the piston upper chamber S2, the piston 11 remains stationary and no nailing operation is performed.

  Next, when both the pulling operation of the trigger 7 and the pressing operation of the push lever 24 against the workpiece W are performed, the plunger 8 is pushed by the link mechanism of the arm plate 26 and the trigger 7 and the trigger valve 9 is moved. The compressed air in the main valve chamber S5 is discharged to the atmosphere through the air passage 21. Then, the main valve 19 is pushed up by the pressure of the compressed air in the pressure accumulating chamber S1, the upper end of the cylinder 10 opens, and at the same time, the communication between the piston upper chamber S2 in the cylinder 10 and the atmosphere is cut off, and the pressure in the pressure accumulating chamber S1 is increased. Compressed air flows into the piston upper chamber S2 in the cylinder 10, and the piston 11 moves downward toward the bottom dead center together with the driver blade 12 due to the pressure of the compressed air, so that the magazine 6 leads to the injection port 25 of the nose 23. The supplied nail 5 is hit by the driver blade 12. Then, the nail 5 struck by the driver blade 12 is guided to the injection port 25 of the nose 23 and driven into the workpiece W. When the piston 11 descends in the cylinder 10 and passes through the air hole 16, the compressed air in the piston upper chamber S2 flows into the return air chamber S4 through the air hole 16 and the check valve 18 and is accumulated. The Further, when the piston 11 descends in the cylinder 10 and reaches the bottom dead center, the piston 11 collides with the piston bumper 14 and elastically deforms the piston bumper 14. Therefore, surplus energy is generated by the elastic deformation of the piston bumper 14. Is absorbed.

  Next, when the trigger 7 is returned to the original position or the push lever 24 is moved away from the driven material W, the plunger 8 returns to the original position, the trigger valve 9 is turned OFF, and the compressed air in the pressure accumulating chamber S1 is supplied to the air passage. 21 and flows into the main valve chamber S5 through the pressure of the compressed air, so that the main valve 19 moves downward and separates from the exhaust cover 3. As shown in FIG. Close contact with the upper end surface. Then, the communication between the pressure accumulating chamber S1 and the piston upper chamber S2 in the cylinder 10 is interrupted, and the exhaust hole 22 is opened to allow the piston upper chamber S2 to communicate with the atmosphere through the exhaust hole 22. Thereby, the compressed air in the piston upper chamber S2 in the cylinder 10 is discharged from the exhaust hole 22 to the atmosphere.

  Then, since the compressed air accumulated in the return air chamber S4 flows into the piston lower chamber S3 in the cylinder 10 through the air hole 17, the piston 11 receives the pressure of the compressed air on the lower surface and moves inside the cylinder 10. The piston 11 and the driver blade 12 return to the initial positions shown in FIG.

  By repeating the above operation, the plurality of nails 5 loaded in the magazine 6 are continuously driven into the workpiece W.

  Next, a structure for connecting the driver blade to the piston constituting the gist of the present invention will be described with reference to FIGS. 2 to 5 are sectional views showing the connecting method of the driver blade to the piston in the order of the steps, and FIG. 6 is a view in the direction of arrow C in FIG.

  As shown in FIG. 2, a slit 11a passing through the center of the shaft is provided in the lower portion of the piston 11 in a direction perpendicular to the paper surface of FIG. 2, and a circular hole 11b passing through the slit 11a is axial with respect to the slit 11a. It penetrates in the perpendicular direction (lateral direction of FIG. 2). In addition, a circular hole 12 a having the same diameter as the circular hole 11 b formed in the piston 11 is provided at one end of the driver blade 12. Here, the portions on both sides sandwiching the slit 11a of the circular hole 11b formed in the piston 11 are denoted as circular hole portions 11b-1 and 11b-2.

  Here, the distance L1 from the end surface 12b of the driver blade 12 on the side where the piston 11 is fitted to the slit 11a to the center O1 of the circular hole 12a is from the slit end surface 11a-1 of the piston 11 to the center O2 of the circular hole 11b. The distance L2 is set larger than the distance L2 (L1> L2), and when the driver blade 12 is statically inserted into the slit 11a of the piston 11 as shown, the center of the circular hole 12a of the drive blade 12 is the circle of the piston 11. The center of the hole 11b is decentered by ε shown on the slit entrance side of the piston 11 (downward in FIG. 2). Therefore, a gap δ is formed between the slit end surface 11a-1 of the piston 11 and the end surface 12b of the driver blade 12, and between the circular hole 11b of the piston 11 and the circular hole 12a of the driver blade 12. Stepped portions A and B as shown are formed.

  Further, in the present embodiment, an inclined surface 13b that extends from the axially intermediate portion of the piston pin 13 to the insertion side end surface 13a is formed obliquely on the outer peripheral portion of the piston pin 13 (see FIG. 6). The inclined surface portion 13b is a tapered surface inclined toward the axial center side (inclined downward in FIG. 2) toward the insertion side end surface 13a of the piston pin 13 (toward the left direction in FIG. 2). The length x is set larger than the width b of the slit 11a formed in the piston 11 (x> b), and the body portion 13c of the piston pin 13 extends from one circular hole portion 11b-1 of the circular hole 11b to the other circle. Even if it press-fits to the position which contacts the hole part 11b-2, it is comprised so that the slope part 13b and the circular hole 12a of the driver blade 12 may not contact. Note that a knurled portion 13d for preventing rotation and retaining is formed at the end of the piston pin 13 opposite to the insertion side (right end in FIG. 2).

  Thus, to connect the driver blade 12 to the piston 11, one end of the driver blade 12 is fitted into the slit 11 a of the piston 11 as shown in FIG. 2. At this time, since the center of the circular hole 12a of the driver blade 12 is eccentric with respect to the circular hole 11b of the piston 11 by ε shown in the drawing as described above, one end of the driver blade 12 is fitted into the slit 11a of the piston 11. Steps A and B as shown in the figure are sometimes formed between the circular hole 11b of the piston 11 and the circular hole 12a of the driver blade 12.

  In the above state, when the piston pin 13 is inserted into one circular hole portion 11b-1 of the circular hole 11b of the piston 11 as shown in FIG. 2, the entire circumference of the portion other than the inclined surface portion 13b of the piston pin 13 Is fitted into the other circular hole portion 11b-2 of the circular hole 11b of the piston 11, so that the piston pin 13 is inserted straight into the circular hole 11b of the piston 11 without being inclined. At this time, since the slope portion 13b is formed on the outer periphery of the insertion side of the piston pin 13, the insertion side end portion 13a of the piston pin 13 passes through the step portion A without contacting the step portion A.

  After that, when the piston pin 13 is further pushed in, as shown in FIG. 3, before the piston pin 13 comes into contact with the stepped portion A, the insertion side end portion 13 a is the other circular hole portion of the circular hole 11 b of the piston 11. 11b-2 is greeted and supported. That is, as described above, the length x of the slope portion 13b formed on the outer peripheral portion of the piston pin 13 is made larger than the width b of the slit 11a of the piston 11 (x> b), and the slope portion 13b is further formed into the circular hole 12a. Therefore, before the insertion side end surface 13a of the piston pin 13 comes into contact with the stepped portion A and tilts, the insertion side end portion 13a of the piston pin 13 is the other circular hole portion 11b of the circular hole 11b of the piston 11. -2, the contact between the piston pin 13 and the stepped portion A is avoided by the inclined surface portion 13b formed on the piston pin 13, so that the piston pin 13 is inserted without being inclined.

  Thereafter, when the piston pin 13 is further pushed in, the inclined surface portion 13b of the piston pin 13 comes into contact with the stepped portion A as shown in FIG. When the piston pin 13 is further pushed in even after the inclined surface portion 13b of the piston pin 13 contacts the stepped portion A in this way, the driver blade 12 is moved in the slit 11a of the piston 11 by the wedge action by the tapered inclined surface portion 13b. When the piston pin 13 is completely press-fitted as shown in FIG. 5 after moving to the slit end surface 11a-1 side (upward in FIG. 4), the end surface 12b of the driver blade 12 is brought into contact with the slit end surface 11a-1 of the piston 11. The gap δ (see FIG. 2) formed between the slit end surface 11 a-1 of the piston 11 and the end surface 12 b of the driver blade 12 in the initial stage becomes 0, and one end of the driver blade 12 is moved by the piston pin 13. Connected to the piston 11.

  As described above, according to the present embodiment, the slope portion 13b is formed on the outer peripheral portion of the piston pin 13, the length x is made larger than the width b of the slit 11a of the piston 11 (x> b), and the slope surface is further increased. Since the portion 13b is not in contact with the circular hole 12a, even if there are step portions A and B between the circular hole 11b of the piston 11 and the circular hole 12a of the driver blade 12, the end surface on the insertion side of the piston pin 13 The insertion side end portion 13a of the piston pin 13 is received by the other circular hole portion 11b-2 of the circular hole 11b of the piston 11 before 13a comes into contact with the stepped portion A and tilts. Since the contact of A is avoided by the slope portion 13b formed on the piston pin 13, the piston pin 13 is not inclined and the circular hole 11b of the piston 11 and the circular hole of the driver blade 12 are not inclined. It is pressed smoothly connecting the driver blade 12 to the piston 11 to 2a. For this reason, even when the piston 11 collides with the piston bumper 14 at the time of driving and an inertial force is generated, stress concentration does not occur in the connecting portion of the driver blade 12 to the piston 11, and the driver blade 12 And the damage of the piston 11 is prevented and their durability is enhanced.

  Further, in the present embodiment, in the process of inserting the piston pin 13 into each of the circular holes 11b and 12a of the piston 11 and the driver blade 12, the driver is driven by the wedge action by the tapered inclined surface portion 13b formed in the piston pin 13. Since the blade 12 moves to the slit end surface 11a-1 side (the anti-slit entrance side) in the slit 11a of the piston 11 and the end surface 12b is in contact with the slit end surface 11a-1 of the piston 11 reliably, The collision load transmitted from the driver blade 12 is received by the slit end surface 11 a-1 of the piston 11. For this reason, the load received by the driver blade 12 and the piston pin 13 is reduced, and the durability of the driver blade 12 and the piston pin 13 is further improved.

  In the above description, the present invention is applied to a pneumatic nailing machine. However, the present invention can be applied to electric and combustion nailing machines in the same manner. Of course, the present invention can be applied to any other driving machine for driving a stopper such as a pin or a staple.

It is a fracture side view of a driving machine (pneumatic nail driver) according to the present invention. It is sectional drawing which shows the connection method of the driver blade to the piston in the driving machine which concerns on this invention. It is sectional drawing which shows the connection method of the driver blade to the piston in the driving machine which concerns on this invention. It is sectional drawing which shows the connection method of the driver blade to the piston in the driving machine which concerns on this invention. It is sectional drawing which shows the connection method of the driver blade to the piston in the driving machine which concerns on this invention. It is a figure of the arrow C direction of FIG. It is a fragmentary perspective view which shows the connection structure of the driver blade to the piston in a driving machine. It is sectional drawing which shows the connection method of the driver blade to the piston in the conventional driving machine. It is sectional drawing which shows the connection method of the driver blade to the piston in the conventional driving machine. It is sectional drawing which shows the connection method of the driver blade to the piston in the conventional driving machine. It is sectional drawing which shows the connection method of the driver blade to the piston in the conventional driving machine.

Explanation of symbols

1 Nailer (driving machine)
2 Body 2a Handle 3 Exhaust cover 4 Air plug 5 Nail (fastener)
6 Magazine 7 Trigger 8 Plunger 9 Trigger valve 10 Cylinder 11 Piston 11a Slit 11a-1 Slit end face 11b Circular hole 11b-1 One circular hole part 11b-2 Other circular hole part 12 Driver blade 12a Circular hole 12b Driver blade end face 13 Piston pin 13a Piston pin insertion side end face 13b Slope part 13c Body part 13d Knurled part 14 Piston bumper 15 Bulkhead 16, 17 Air hole 18 Check valve 19 Main valve 20 Spring 21 Air passage 22 Exhaust hole 23 Nose 24 Push lever 25 Exit 26 Arm plate A, B Stepped portion b Piston slit width L1 Distance from the end face of the driver blade to the center of the circular hole L2 Distance from the slit end face of the piston to the circular hole O1 Center of the circular hole 12a O2 Circular hole 11 Center of b S1 Pressure accumulating chamber S2 Piston upper chamber S3 Piston lower chamber S4 Return air chamber S5 Main valve chamber x Axial length of inclined surface W Material to be driven δ Clearance between driver blade end face and slit end face ε Eccentricity of the hole center piston with respect to the center of the circular hole

Claims (2)

A piston that reciprocates in the cylinder; and a driver blade that reciprocates with the piston and strikes a stopper; and one end of the driver blade is fitted into a slit formed in the piston, and the driver blade and the piston In the driving machine formed by connecting one end of the driver blade to the piston by a piston pin press-fitted into each of the holes formed in
On the outer periphery of the piston pin, a slope portion extending from the axial intermediate portion of the piston pin to the insertion side end surface is formed, and the axial length of the slope portion is larger than the width of the slit formed in the piston. A driving machine characterized by setting.   The slope portion is a tapered surface inclined toward the axial center toward the insertion side end surface of the piston pin, and the distance from the end surface on the side of the driver blade fitted to the slit of the piston to the center of the hole, Set larger than the distance from the slit end surface of the piston to the center of the hole, and when the driver blade is statically inserted into the piston slit, the center of the drive blade hole is at the piston slit entrance with respect to the center of the piston hole. 2. The driving machine according to claim 1, wherein the driving machine is eccentric to the side.

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