JPS6134950B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention uses compressed air as a power source to reciprocate a striking piston that is slidably housed in a striking cylinder, and uses a rod-shaped driver rigidly connected to this striking piston to generate a large number of blows. A nail feeder built into a pneumatic nailer that separates the connected nails, which are connected in parallel at a constant pitch using a connecting material, into individual nails and drives the separated nails into the material to be driven. Regarding the mechanism.

Conventionally, commonly used pneumatic nailers employ a nail feeding method in which the second nail positioned from the tip of a connected nail is fed into the nail driving nose. According to this nail feeding method, the tip of the nail feeding pawl does not enter the nail driving nose, so even when hitting the head of the nail in the nail driving nose with a rod-shaped driver, the nail feeding pawl does not enter the nail driving nose. Accidents in which the tip end is struck by the rod-shaped driver do not occur, and it is not so difficult to control the timing of each operation of the nail feeding claw using compressed air.

However, the above nail feeding method cannot avoid the following two serious drawbacks.

First, with the nail feeding method described above, each nail of the connecting nail is driven in sequence, and the nail located at the rearmost end of the connecting nail cannot be stably fed into the nail driving nose. Even if the nail is fed into the material, the nail cannot be supported within the nail driving nose by the nail feeding pawl, so it is impossible to drive the nail into the material to be driven.

Next, depending on the above nail feeding method, the parallel pitch of the connected nails that can be adopted is limited to a small one. That is, each nail constituting the widely used connecting nail consists of a shank portion and a circular head, and the diameter of the circular head is two to three times the diameter of the shank portion. Each nail is connected by a connecting material such as a wire in a positional relationship such that its circular head contacts the circumferential surface of the shank of another nail located immediately after this nail, and the pitch (connection) between the shank of each nail is Care has been taken to keep the parallel pitch of the nails as small as possible. The connecting material is cut using a rod-shaped driver and a nail feeding claw in a method similar to shearing, so it has a restriction that it cannot have a large bending rigidity. Therefore, in order to support the weight of each nail, the minimum bending Rigidity is imparted to the connecting member.

The diameter of the circular head is 2 to 3 times the diameter of the shank.
In the case of a connecting member made of double nails, since the parallel pitch is relatively small, it is not difficult to hold the nail at the leading end in a stable position within the nail driving nose by the connecting member extending from the next position.

However, in the case of nails that require a large parallel pitch of connecting members, that is, nails whose circular head diameter is approximately four times or more the diameter of the shank (hereinafter referred to as large-head nails), The support of the nail located at the tip of the nail becomes extremely unstable.

The object of the present invention is to provide a nail feeder for a pneumatic nailer in which a nail positioned at the tip of a connected nail is fed into a nail-driving nose by a nail-feeding pawl, and is supported within the nail-driving nose. It is to provide a mechanism. In order to achieve this object, the present invention has a structure in which a connecting nail, in which a number of nails are connected with a constant parallel pitch by a connecting member, is biased by a spring so as to be swingable at the tip of a piston rod of a nail feeding piston/cylinder mechanism. In the nail feeding mechanism of a pneumatic nailer in which a rod-shaped driver reciprocates by a nail feeding pawl and the nail is fed into a nail driving nose that has a nail pick-up section directly below the part where the nail feeding pawl moves, a nail feeding piston cylinder is used. The nail feed cylinder of the mechanism is provided with a cap on the rear end side, and one end of the advancing air supply passage to which compressed air is selectively supplied and the retreating air supply passage to which compressed air is constantly supplied are mutually connected. One end of a compression coil spring is fixed to the rear end side of the nail feeding piston of the nail feeding piston/cylinder mechanism facing the advancing air supply passage, and the other end of the compression coil spring is opened in the opposite position. When the nail feed piston is advanced to the maximum extent, it protrudes from the rear end face of the nail feed piston by a certain amount, and has a certain amount of clearance between it and the cap, and the nail feed pawl The nail located at the tip of the connecting nail is supported in the nail driving nose, and when the nail is struck by the rod-shaped driver, the compressed air in the advancing air supply passage is released into the atmosphere, and the nail feeding piston is first The nail pick-up part and the nail feeding pawl work together to prevent the nail from coming out from the nail driving nose, and then the compression coil spring is moved back a distance equal to the protrusion amount of the compression coil spring. It is characterized in that the nail feeding claw moves back to the maximum extent under load and picks up the nail located at the tip of the connected nail.

Hereinafter, preferred embodiments of the present invention will be described in detail with reference to FIGS. 1 to 6. FIG. 1 is a vertical cross-sectional view of a main part of a pneumatic nailing machine 1 incorporating the nail feeding mechanism of the present invention, and FIG. 2 is a vertical cross-sectional view of the remaining part of the pneumatic nailing machine 1.

A percussion cylinder 3 is disposed inside the housing 2 of the pneumatic nailer 1, a percussion piston 4 is slidably housed in the percussion cylinder 3, and a rod-shaped driver 5 is rigidly connected to the percussion piston 4. ing.

This rod-shaped driver 5 reciprocates within a nail driving nose 32 projecting downward from the housing 2, and has a cross section as shown in FIG.
An arch-shaped clearance groove 3 is provided on the rear end side of the rod-shaped driver 5.
3 extends in the axial direction of this driver 5, and because of the existence of this arcuate relief groove 33, when hitting the round head 35a of the large head nail 35 located at the tip of the connecting nail 34, the second one from the tip The circular head 36a of the large head nail 36 that is located is not struck.

Compressed air for reciprocating the striking piston 4 is supplied via a head valve 8 from a main air chamber 7 formed inside the handle portion 6 of the housing 2 and around the striking cylinder 3.

This main chamber 7 is connected to an air hose (not shown) extending from an air compressor (not shown) connected to an air plug 37 provided at the rear end of the handle portion 6 shown in FIG. Air is constantly supplied. A relief valve 38 is provided below the air plug 37 to maintain the air pressure within the main air chamber 7 constant.

The head valve 8 is arranged in an annular shape above the striking cylinder 3, and includes a head valve cylinder 9 formed with an annular hole at the upper end of the housing 2, and a head valve piston 10 slidably housed inside the head valve cylinder 9. It consists of

A control chamber 11 formed above the head valve piston 10 as part of the head valve cylinder 9
communicates with a large-diameter trigger valve chamber 22a of the trigger valve 18 via a head valve control air passage 12.

The trigger valve 18 includes a trigger valve cylinder 19 and a hollow trigger valve piston 2 slidably disposed inside the trigger valve cylinder 19.
0a and a trigger valve stem 20b slidably disposed within the trigger valve piston 20a. A compressed air introduction hole 21 communicating with the main air chamber 7 is bored in the upper end portion of the trigger valve piston 20a, and a small diameter trigger valve chamber 22b is formed.
is familiar with This small-diameter trigger valve chamber 22b communicates with a valve piston lower chamber 22c of the trigger valve cylinder 19. A large diameter trigger valve chamber 22a communicating with the main air chamber 7 is located between the trigger valve cylinder 19 and the valve piston 20a.
is formed. This large trigger valve chamber 22
a communicates with the head valve control air passage 12 and also with the advancing air supply passage 16.

On the other hand, the upper end portion of the trigger valve stem portion 20b is provided with a stem small-diameter upper end portion 25 that moves within the small-diameter trigger valve chamber 22b, and a joint stem portion 26 is provided continuously to the stem small-diameter upper end portion 25. This joint stem portion 26 is connected to the intermediate stem portion 2.
7 and an O-ring fitting small-diameter portion 29 to a trigger valve stem operating portion 30 . The small-diameter upper end portion 25 of the stem is always resiliently biased downward by a return compression spring 31 disposed within the small-diameter trigger valve chamber 22b. Therefore, manual trigger 10
5 is not pulled up and the trigger safety arm 34a is not pushed up, the O-ring fitting small diameter portion 29 fits into the fitting hole 106 formed at the lower end of the trigger valve cylinder 19. However, the trigger valve piston 20a is moving upward in the figure, blocking off the large-diameter trigger valve chamber 22a and the atmosphere. At this time, the main air chamber 7 and the large-diameter trigger valve chamber 22a are communicating through the gap 107 between the trigger valve cylinder 19 and the valve piston 20a, and compressed air flows through the head valve control air passage 12. Control room 1
It is guided by 1. The head valve piston 10 is at the bottom dead center position due to the pressure of this compressed air.

When the trigger safety arm 34a is pushed up and the manual trigger 105 is pulled up, the valve piston lower chamber 22c is
At the same time, the valve piston 20a moves downward in FIG. 1.
As a result, the gap 107 that communicates the large-diameter trigger valve chamber 22a and the main air chamber 7 is closed, and the large-diameter trigger valve chamber 22a, the head valve control air passage 12, and the advancing air supply passage 16 communicate with the atmosphere. .

The gap 107 is formed by the fact that the inner diameter of the trigger valve cylinder 19 is slightly larger than the maximum outer diameter of the trigger valve piston 20a, and that the trigger valve cylinder 1
9 and the trigger valve piston 20a are both made of metal. The compressed air in the control chamber 11 is removed via the head valve control air passage 12, so that the head valve piston 10 maintains the differential pressure between the air pressure in the control chamber 11 and the air pressure in the main air chamber 7. is pushed up toward top dead center. As the head valve piston 10 moves to the top dead center, the compressed air in the main air chamber 7 flows into the top dead center side chamber 3A of the striking cylinder 3 all at once, and the striking piston 4
act on the upper surface of the striking piston 4 to rapidly lower it toward the bottom dead center.

A nail feeding mechanism is disposed between the rear end side of the nail driving nose 32 and the rear end side of the handle portion 6. This nail feeding mechanism is composed of a nail guide plate 39, a nail feeding piston/cylinder mechanism 40, a nail feeding pawl 41, a check pawl 42, and a door mechanism 43.
The nail feeding mechanism unwinds the connecting nails 34 from the circular container-shaped nail magazine 44a, and feeds the nails one by one toward the nail driving nose 32.

A trapezoidal opening 44 is provided on the front side of the nail guide plate 39 (the left end side of the nail guide plate 39 in FIG. 1), and the nail feeding pawl 41 guides the nail inside this opening 44. It reciprocates in the longitudinal direction of the plate 39.

The nail feed pawl 41 is disposed at the tip 46a of the piston rod 46 of the nail feed piston 45 so as to be pivotable about a pivot shaft 47. The nail feeding pawl 41 holds the piston rod 46 between upper and lower sides by a mounting yoke 48, and is biased counterclockwise in FIG. 3 by a torsion coil spring 49. However, the stopping pin 50 is fixed to the nail feeding claw 41,
The piston rod 46 is attached to this stopping pin 50.
A part of the tip 46a of the nail feeding claw 41 comes into contact with the nail feeding claw 41, and the counterclockwise rotation of the nail feeding claw 41 is restricted to a certain limit. This state is shown in FIG. In the state shown in FIG. 3, the tip end surface 41a of the nail feeding claw 41 protrudes close to the central axis of the nail driving nose 32.

The torsion coil spring 49 has two coil parts 5 above and below the mounting yoke 48 of the nail feeding claw 41.
1, and one end side 51a of these coil portions 51 are integrally connected. The other end 51b of the coil portion 51 is brought into contact with the shoulder portion 52 of the nail feed pawl 41, so that the torsion coil spring 49 biases the nail feed pawl 41 in the counterclockwise direction as described above.

Connecting material passage grooves 53a and 53b are provided at the upper end portion and intermediate height portion of the nail feeding pawl 41.
1 in the horizontal direction. On the other hand, nail feeding claw 4
A groove 54 is formed in the vertical direction of 1. This groove 5
The front wall portion 55 of No. 4 prevents the large head nail 36 located second from the tip of the connecting nail 34 from entering the nail driving nose 32 by being dragged by the cutting operation of the large head nail 35 located at the tip. It is for.

A nail guide plate 39 is provided at the lower end of the nail driving nose 32.
A nail picking-up portion 32b having a tapered surface 32a is formed below the opening 44. 1st
5 or 6 shows a state in which the tapered surface 32a of the nail pick-up portion 32b is fully performing its original function. That is, in the retracted position of the nail feed pawl 41 shown in FIG.
The lower part 55a of the front wall part 55 of No. 1 and the nail pick-up part 32
The possibility that the nail foot 35b of the large head nail 35 will deviate to the rear of the nail driving nose 32 is completely eliminated by the tapered surface 32a of the large head nail 35.

A rear wall 55b is provided in the nail feed claw 41 and protrudes in the direction opposite to the direction in which the front wall portion 55 protrudes,
This rear wall 55b is a stopping wall portion 5 extending from the nail driving nose 32 in parallel with the nail guide plate 39.
6, thereby preventing the nail feeding pawl 41 that has advanced to the leading edge from moving in a direction perpendicular to the nail guide plate 39 (upward in FIG. 3).

The pivot 47 is a type of stepped pin having narrow diameter portions at its upper and lower ends, and the shoulder portion 66 of the stepped pin formed between the thick diameter portion and these narrow diameter portions prevents the spring from restoring. As the piston rod 46 is prevented from moving in the horizontal axis direction by the eccentric coil portion 51 due to force,
Its omission is prevented.

A nail feed cylinder 60 provided on the rear side of the nail guide plate 39 has a first bore part 61 and a second bore part 62. A shoulder portion 63 is formed between the first bore portion 61 and the second bore portion 62.

A cap 64 is fitted into the rear end of the second bore section 62 (the right end of the second bore section 62 in FIG. 1) and is fixed by a retaining ring 65.

A first O-ring 67 is fitted into the inner wall of the first bore portion 61, and a second O-ring 68 is fitted into the cap 64.

One end 69a of the retreating air supply passage 69 is open at the shoulder portion 63, and the other end 69b of the retreating air supply passage 69 is open into the main air chamber 7.

Advance air supply passage 16 at the position of cap 64
One end side 16a is open, and the other end side 16b of the advancing air supply passage 16 is open to the large diameter trigger valve chamber 2.
It communicates with 2a.

A piston rod 46 is slidably housed in the first bore portion 61, and a nail feeding piston 45 is slidably housed in the second bore portion 62. A cylindrical piston portion 7 is provided on the rear end side of the nail feeding piston 45 (the right end side of the nail feeding piston 45 in FIG. 1).
0, and one end 72 of a compression coil spring 72 is provided on the front end wall surface 71 of this cylindrical piston portion 70.
a is fixed. A thick-walled piston portion 73 is located at the front end of the nail-feeding piston 45 (on the left end side of the nail-feeding piston 45 in FIG. 1), and a third O-ring 74 is fitted into this thick-walled piston portion 73. ing.

The maximum amount of advancement of the piston rod 46 is determined by the abutment of the shoulder 75 formed between the nail feed piston 45 and the piston rod 46 against the shoulder 63.

As shown in FIG. 1, when the piston rod 46 is fully advanced, a certain amount of clearance A exists between the other end 72b of the compression coil spring 72 and the inner wall surface 64a of the cap 64.

On the other hand, in the rest position of the nail feed piston 45 shown in FIG. 1, the compression coil spring 72 is in a fully extended state, and the other end 72 of the compression coil spring 72 is
b has a constant protrusion amount B.

When compressed air is present in both the advancing air supply passage 16 and the retreating air supply passage 69, the total pressure of the compressed air acting on the shoulder portion 75 of the nail feeding piston 45 and the pressure of the nail feeding piston 45 are Rear end surface 4
5a and the front end wall surface 7 of the cylindrical piston portion 70
Due to the difference between the total pressure of the compressed air and the total pressure acting on the nail feed piston 45, the nail feed piston 45 remains at the maximum advanced position.

Compressed air is present in the retreat air supply passage 69,
On the other hand, when compressed air is not present in the advancing air supply passage 16, the pressure of the compressed air acting on the shoulder portion 75 causes the nail feeding piston 45 to be pushed back to the maximum retracted position.

Hereinafter, the operation of the nail feeding mechanism of the present invention will be explained. As shown in FIG. 1, the main air chamber 7 is filled with compressed air, the manual trigger 105 is not pulled, and the trigger safety arm 34a
If the nail feed piston 45 is not pushed up against the nail driving nose 32, compressed air is present in both the advancing air supply passage 16 and the retreating air supply passage 69, so the nail feeding piston 45 advances to the maximum extent. , and is stationary at that position.

Next, the manual trigger 105 is pulled, and the trigger safety arm 34a is moved to the nail driving nose 3.
2, the compressed air in the control chamber 11 and the advancing air supply passage 16 is released into the atmosphere via the trigger valve 18.

As the pressure inside the control chamber 11 drops to atmospheric pressure, the head valve piston 10 moves toward the top dead center, causing communication between the main air chamber 7 and the top dead center side chamber 3A, and the striking piston 4 suddenly descends. (See Figure 5).

On the other hand, during this time, the compressed air in the nail feed cylinder 60 is released into the atmosphere through the advancing air supply passage 16, so that the nail feed piston 45 begins to retreat. As shown in FIG. 5, the nail feed piston 45 moves a distance equal to the clearance A at the moment the rod-shaped driver 5 hits the circular head 35a of the large-head nail 35.

Compression of the compression coil spring 72 is started at the retracted position of the nail feed piston 45 shown in FIG. That is, during this instant, the rod-shaped driver 5
pushes down the large head nail 35, and the nail foot 35b of this large head nail 35 touches the tapered surface 32 of the nail pick-up part 32b.
The nail foot 35b reaches a position facing the nail tip 35a (a position where the nail foot 35b cannot pop out from the nail driving nose 32).

The position of the nail feeding pawl 41 when moved by a distance equal to the clearance A is also a position where there is no risk of being hit by the rod-shaped driver 5.

When the rod-shaped driver 5 drives the large-head nail 35 into the material to be driven, the nail feeding claw 41 also comes to rest at the maximum retracted position, and at that position the second large-head nail 36 from the tip is driven. Complete preparations for feeding into the nose 32 are made. That is, the front wall portion 55 of the nail feeding claw 41 is stationary immediately behind the shank portion 36c of the large head nail 36.

Next, when the manual trigger 105 is released and the trigger safety arm 34a separates from the workpiece, compressed air flows through the advancing air supply passage 16 and the head valve control air passage 12 into the control chamber 11 and the nail feeding cylinder 60. The hammer piston 4 is moved toward the top dead center by the compressed air flowing into the bottom dead center side chamber 3B from the blowback air check 7a, and at the same time, the nail feed claw 41 is moved by the advancement of the nail feed piston 45. A large head nail 36 is sent into the nail driving nose 32.

In the above embodiment, a connecting nail in which large headed nails were connected was explained, but the nail is made of a nail with no head such as a headed nail or a finishing nail whose circular head diameter is two or three times the diameter of the shank part. Even pneumatic nailers that use connected nails exhibit superior effects compared to conventional nail feeding methods.

As described above, according to the present invention, the nail located at the tip of the connecting nail is directly fed into the nail driving nose by the nail feeding claw, so that it can be used even if the parallel pitch of the connecting nails is large. Moreover, even the nail located at the rearmost end of the connected nails can be fed into the nail driving nose in a stable posture.

[Brief explanation of the drawing]

FIG. 1 is a vertical sectional view of the main parts of a pneumatic nailing machine incorporating a nail feeding mechanism according to an embodiment of the present invention, and FIG.
The figure is a longitudinal sectional view of the remaining part of the nailing machine, and
It is connected to the cutting line - in FIG. 1 at the cutting line -. FIG. 3 is a sectional view taken along the line -- in FIG. 1, and only a portion is shown in cross section. Fig. 4 is a cross-sectional view of the rod-shaped driver, Fig. 5 is an operation diagram of the nail feeding mechanism showing the moment when the rod-shaped driver hits the nail located at the tip of the connected nail, and Fig. 6 is a cross-sectional view of the rod-shaped driver. It is an operation diagram of the nail feeding mechanism showing the moment when the nail is driven into the material to be driven. DESCRIPTION OF SYMBOLS 1...Pneumatic nailer, 5...Rod-shaped driver, 16...Advancing air supply passage, 16a...One end side, 32...Nail driving nose, 32b...Nail pick-up part, 34...Connection Nails, 35 and 36...
Big head nail, 40...Nail feed piston/cylinder mechanism, 41...Nail feed pawl, 45...Nail feed piston, 45a...Rear end surface, 46...Piston rod, 47...Pivot, 49...Twisted coil spring, 6
4...Cap, 69...Reverse air supply passage,
69a... One end side, 72... Compression coil spring, 7
2a...One end, 72b...Other end,...Nail feeding mechanism, A...Clearance, B...Protrusion amount.

Claims (1)

[Claims] 1 A rod-shaped driver reciprocates a connecting nail, which is made by connecting a number of nails with a constant parallel pitch using a connecting material, to the tip of a piston rod of a nail feeding piston/cylinder mechanism, which is biased by a spring so as to be able to swing. In the nail feeding mechanism of a pneumatic nailer that feeds the nail into the nail driving nose which has a nail pick-up part directly below the part where the nail feeding claw moves, the rear end of the nail feeding piston/cylinder mechanism is connected to a trigger valve, The front end communicates with the main chamber, and a cap is provided at the rear end side of the nail feeding cylinder of the nail feeding piston/cylinder mechanism, and an advancing air supply path and constant compressed air are selectively supplied with compressed air. One end of the retraction air supply path to which is supplied is opened at opposite positions, and one end of a compression coil spring is located on the rear end side facing the advance air supply path of the nail feed piston of the nail feed piston/cylinder mechanism. The other end of the fixed and fully extended compression coil spring protrudes from the rear end face of the nail feed piston by a certain amount when the nail feed piston is advanced to the maximum extent, and also extends between the nail feed piston and the cap. has a certain amount of clearance corresponding to the distance from the position where the tip of the nail feed pawl supports the nail in the nose until the feed pawl retreats to the same plane on the inner wall of the nose; The feed pawl supports the nail located at the tip of the connecting nail in the nail driving nose, and when the rod-shaped driver hits the nail, the compressed air in the advancing air supply path is released into the atmosphere and the nail feed piston is activated. first retreats a distance equal to the above clearance, and the nail pick-up part and nail feeding pawl work together to prevent the nail from flying out from the nail driving nose, and then retreats a distance equal to the protrusion amount of the compression coil spring. A nail feeding mechanism of a pneumatic nailer, characterized in that the nail feeding claw moves back to the maximum extent under the load of a compression coil spring and picks up the nail located at the tip of the connected nail.