JPH08216042A - Driving-depth control mechanism for use in screwdriver - Google Patents

Abstract

PURPOSE: To enable a contact member to be returned to its initial position and a pinion gear to be surely rotated and returned to a predetermined position even if a trigger lever is released when the contact member has moved backward. CONSTITUTION: An engaging step 27 is formed in a part of a contact member 26, and a stopper piece 32 which can be rotated to a first position where it advances onto the engaging step 27 of the contact member 26 and to a second position where it retreats from the top of the engaging step 27 is supported on a rotating block 31 integrated with the drive shaft of the pinion gear 17 of a rack-and-pinion mechanism. Also, the stopper piece 32 is energized to the first position prior to the actuation of the rack-and-pinion mechanism, is engaged with the engaging step 27 during a driving operation so as to regulate the amount of backward movement of the contact member 26, and is rotated to the second position during screwing.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a control mechanism for adjusting a driving depth of a screw driving operation in a screw driving machine which performs a screw driving operation followed by a screw driving operation.

[0002]

2. Description of the Related Art As is known from Japanese Utility Model Laid-Open No. 6-36774, a screw driving machine is equipped with a driver that is driven to strike in the axial direction and is rotated about the axial center, and this driver is driven by compressed air. Then, the screw is driven into the material to be driven and then screwed. If the shaft of the screw penetrates the material to be driven during driving, the next screwing becomes meaningless and pulling proof strength cannot be obtained.Therefore, set the screw driving depth according to the thickness of the driven material. Maintaining a predetermined depth is important for maintaining the holding power.

For this reason, in the prior art, FIGS.
As shown in FIG. 5, in order to make the end position of the driving stroke of the driver constant from the surface of the material to be driven, the grounding member 26 abutting on the surface of the material to be driven is slidable along the nose portion for injecting the screw. By arranging and stopping the grounding member 26 at a predetermined stop position at the time of driving to maintain the nose portion at a constant height from the surface of the material to be driven,
A mechanism to adjust the screw driving depth is adopted.
After the driving, when the screwing is started, the stop of the ground member 26 is released and the tip of the nose portion is moved to a position where it comes into contact with the surface of the material to be driven.

The above-mentioned driving depth control mechanism is constructed by engaging the upper end of the grounding member 26 with the rotary arm 28 formed integrally with the rotary shaft of the pinion rack mechanism. Then, when the trigger lever is operated, the screw driving process is started, the pinion rack mechanism is subsequently operated, the rotary arm 28 is rotated in association with the operation of the rack, and the grounding member 26 is released from the stopped state. Screwing is done. The upper end of the grounding member 26 moves beyond the position of the rotating arm 28 and moves to the upper retracted position. Then, when the trigger lever is released after screwing in, the rack moves in the returning direction and the rotating arm 28 returns to the initial position and rotates.

However, during this return rotation, the rotating arm 28 may collide with the side surface of the grounding member 26 and interfere with the returning operation of the grounding member 26. If the grounding member 26 does not return to the initial position, not only the driving depth will not be secured at the time of driving the next screw, but also the pinion gear 32 that is fixed coaxially with the rotating arm 28 cannot return and rotate to the initial position. There is a shortage of the screwing-in rotational speed of the screw, and a phenomenon that a predetermined holding force cannot be obtained occurs.

[0006]

SUMMARY OF THE INVENTION The present invention solves the above-mentioned drawbacks, and even if the trigger lever is released while the contact member is retracted along the nose portion, the contact member can be returned to the initial position, and the pinion gear can also be moved to the predetermined position. It is an object of the present invention to provide a driving depth control mechanism in a screw driving machine capable of reliably returning and rotating up to.

[0007]

In order to achieve the above object, a driving depth control mechanism in a screw driving machine according to the present invention drives a screw in a nose portion by a striking mechanism and operates a pinion rack mechanism. In a screw driving machine equipped with a screwdriver that rotates with respect to the screw, it is normally arranged so as to be retractable along the nose portion by protruding from the tip of the nose portion and pressing it against the surface of the material to be driven. The engaging step portion is formed in a part of the contact member, and the rotary block integrally provided with the shaft of the pinion gear of the pinion rack mechanism is advanced to the engaging step portion of the contact member. The stopper piece is supported so that it can be rotated to a second position where it is retracted from the position and the engagement step portion, and this stopper piece is attached to the pinion rack. The spring is biased to the first position before the structure is actuated, and the stopper piece is engaged with the engaging step portion of the contact member during the driving operation to regulate the retracting movement amount of the contact member, and at the time of screwing in. It is characterized in that the stopper piece is rotated to the second position in conjunction with the pinion gear.

[0008]

In the above structure, when the tip of the contact member is pressed against the surface of the material to be driven in driving the screw, the contact member slides along the nose portion. When the striking mechanism is operated, the driving screw is driven into the material to be driven. At this time, since the stopper piece is in the first position, the stopper piece engages with the engagement step portion while the contact member is retracting along the nose portion, and the retracting movement amount is restricted. Since the tip of the contact member projects more than the tip of the nose portion, even if the driver of the striking mechanism moves by a predetermined movement amount, the driving depth of the screw becomes shallower by the amount of protrusion from the nose portion of the contact member. Therefore, the driving depth of the screw is adjusted and controlled.

When the pinion rack mechanism is actuated following the driving of the screw, the pinion gear rotates, and the stopper piece rotates and moves in conjunction with the pinion gear to the second position. The contact member retracts and moves again. Therefore, the screw can be screwed. Then, since the driver is rotationally driven by the pinion rack mechanism, the screw is screwed into the material to be driven.

After screwing, the rack of the pinion rack mechanism also returns to the initial position, and the pinion gear also rotates to the initial position. At this time, if the contact member has already returned to the initial projecting position, the stopper piece rotated together with the pinion gear also moves to the first position. On the other hand, when the contact member is in the retracted state, the stopper piece rotated together with the pinion hits the contact member. However, since the stopper piece is rotatably supported by the drive shaft of the pinion gear, the drive shaft rotates to the initial position together with the pinion gear, but the stopper piece waits at the position where it hits the contact member, and the contact member is initialized. When returning to the projecting position, the spring rotates and returns to the first position.

As described above, even if the trigger lever is released with the contact member retracted along the nose portion, the contact member can be returned to the initial position, and the pinion gear can be surely rotated to the predetermined position. be able to. Therefore, by interfering with the return operation of the contact member, the driving depth cannot be secured when driving the next screw, or the number of rotations of the next screw becomes insufficient, and a predetermined holding force cannot be obtained. It is possible to effectively prevent the occurrence of the phenomenon.

[0012]

1 shows a screw driving machine, which comprises a body 1, a nose portion 4 having an injection port 3 for a screw 2, and a grip portion 5. The body 1 is driven by the compressed air supplied from the air supply source 6 to drive the driving screw 2 into the striking mechanism 7, the pinion rack mechanism 8 to screw the driven driving screw 2 into the body 1 A trigger mechanism 9 for controlling is provided. The compressed air is supplied from the air supply source 6 to the air storage chambers 10a and 10b formed in the grip portion 5 and the body 1, respectively.

The striking mechanism 7 is constituted by a piston / cylinder mechanism similar to that employed in a normal nail driving machine, and compressed air from the air storage chamber of the body 1 is supplied into the striking cylinder 11 to strike the striking piston. A screwdriver 13 (not shown) is driven to drive a driver 13 which is integrally connected to the screw 12, and an injection port 3 of a nose portion 4 is driven by a screw supply device (not shown) from a screw supply passage of a magazine 15.
The driving screw 2 supplied therein is driven into the material to be driven to a certain depth.

The driver 13 is guided by the driver guide 14 so as to be slidable in the driving direction, and is rotated by the driver guide 14. That is, as shown in FIG. 2, the driver guide 14 is rotatably supported by the nose portion 4 around the axis of the driver 13, and a rectangular guide hole 15 is formed in the center thereof. The driver 1 is installed in the guide hole 15.
3 is inserted. As a result, the driver 13 can slide in the axial direction independently of the driver guide 14,
It rotates following the rotation of the driver guide 14.

The pinion / rack mechanism 8 converts the linear motion of the rack 16 into the rotational motion of the pinion gear 17, and the rack 16 is connected to the air storage chamber 10a in the grip portion 5 by a cylinder 18 of a piston / cylinder mechanism. Is integrally formed with a piston rod 20 of a piston 19 which is slidably housed in the inside thereof. Cylinder 18
The rack 16 is reciprocally moved forward and backward together with the piston 19 by the compressed air alternately introduced into the rear and front supply / discharge holes 24 and 25, and the pinion gear 17 meshed with the rack 16 is reciprocally rotated. The pinion gear 17 is the intermediate gear 21.
The gears formed on the outer periphery of the driver guide 14 are engaged with each other, and the rotation of the pinion gear 17 causes the driver guide 14 to rotate.

Next, the trigger mechanism 9 is a valve mechanism for controlling the supply of driving air to the striking mechanism 7 by manually operating the trigger lever 22, and the driving air is the striking piston 1 of the striking mechanism 7.
Compressed air that is supplied to the upper surface of 2 to drive the piston 12 and is compressed to the lower surface side of the striking piston 12 is sent to the pinion rack mechanism 8 via the connecting pipe 23, and the supply / discharge hole 24 of the cylinder , 25 is switched to operate the pinion rack mechanism 8.

The trigger lever 22 is constructed so that it can be operated under the condition that the contact member 26 provided along the nose portion 4 detects the material to be driven. FIG.
As shown in (b), the middle portion of the contact member 26 is bent, and an engagement step portion 27 is formed near the bent portion 28. The upper end is arranged so as to face the trigger lever 22. Further, it is normally biased so as to project from the tip of the nose portion 4, and is arranged so as to be able to retract along the nose portion 4 by being pressed against the surface of the material to be driven. The trigger lever 22 is allowed to move so as to operate the trigger mechanism 9.

By the way, as shown in FIGS. 3 and 4A and 4B, a rotary block 31 is fixed to the upper end of a shaft 30 integrally attached to the pinion gear 17 of the pinion rack mechanism 8. A stopper piece 32 is supported on the rotation block 31. The stopper piece 32 is located at the first position (the position shown in FIGS. 4 (a), (b) and FIG. 5 (a), (b)) on the engagement stepped portion 27 of the contact member 26 and the engagement stepped portion 27. Second position to retract from above (Figs. 6 (a) and (b) and Fig. 7)
(Positions (a) and (b)) are rotatably supported, and are biased by a spring 33 to be in the first position before the operation of the pinion rack mechanism 8.

The stopper piece 32 is used as the contact member 2.
When the engaging step portion 27 of No. 6 is engaged, the contact member 26 cannot be further retracted and stops, but the trigger mechanism 9 can be operated even with this moving amount, and the contact member 26 is in the stop position. The tip of 26 is configured to project more than the tip of the nose portion 4.

The pinion rotates less than one rotation (for example, 270 °) by one stroke of the rack 16, while the driver guide 14 rotates about two rotations.

In the above structure, when the tip of the contact member 26 is pressed against the surface of the material to be driven in driving the screw 2, the contact member 26 slides along the nose portion 4. Then, the striking mechanism 7 is activated by pulling the trigger lever 22, and the striking piston 1
The driver 13 is driven together with the driving screw 2 and the driving screw 2 supplied to the injection port 3 is driven into the driven material 34. At this time, since the stopper piece 32 is in the first position as shown in FIGS.
FIG. 5 (a) while 6 is retracting along the nose portion 4.
As shown in (b), the stopper piece 32 engages with the engagement step portion 27 to regulate the retracting movement amount thereof. Since the tip of the contact member 26 projects more than the tip of the nose portion 4, even if the driver 13 of the striking mechanism 7 moves by a predetermined movement amount, the driving depth of the screw 2 is from the nose portion 4 of the contact member 26. It becomes shallower by the amount of protrusion. Therefore, the driving depth of the screw 2 is adjusted and controlled.

When the pinion / rack mechanism 8 is actuated following the driving of the screw 2, the rack 16 moves forward, and the pinion gear 17 rotates in conjunction with this, and the pinion gear 17 is rotated, as shown in FIGS.
As shown in FIG. 3, the stopper piece 32 is rotationally moved to the second position in conjunction with the pinion gear 17, so that the stopper piece 3
2 retracts from the engagement step portion 27, and the contact member 26 retracts again. Therefore, the screw 2 can be screwed. Then, as the pinion gear 17 rotates, the intermediate gear 21 and the driver guide 14 rotate, and the driver 13 is rotationally driven in conjunction with this, so that the screw 2 is screwed into the material 34 to be driven.

After screwing in, by releasing the trigger lever 22, the striking piston 12 and the driver 13 return to the initial position, and the rack 16 of the pinion rack mechanism 8 also returns to the initial position, and the pinion gear 17 moves. Also rotates to the initial position. At this time, if the contact member 26 has already returned to the initial protruding position,
Stopper piece 32 rotated together with the pinion gear 17
Also moves to the first position. On the other hand, when the contact member 26 is in the retracted state, the stopper piece 32 rotated together with the pinion hits the contact member 26 (see FIGS. 7A and 7B). However, since the stopper piece 32 is rotatably supported by the drive shaft of the pinion gear 17, the drive shaft rotates to the initial position together with the pinion gear 17, but the stopper piece 32 waits at the position where it hits the contact member 26. When the contact member 26 returns to the initial projecting position, the spring bias of the spring 33 causes the contact member 26 to return to the first position and rotate.

[Brief description of drawings]

FIG. 1 is a vertical cross-sectional view of a main part of a screw driving machine according to the present invention.

FIG. 2 is a sectional view showing a pinion rack mechanism of the screw driving machine.

FIG. 3 is a perspective view of a rotation block.

4 (a) and (b) are a plan view and a central longitudinal cross-sectional view, respectively, of an operation state in an initial state.

5 (a) and 5 (b) are a plan view and a central longitudinal sectional view, respectively, of an operation mode at the time of striking.

6 (a) and 6 (b) are a plan view and a central longitudinal sectional view, respectively, of an operation state when screwed in.

7 (a) and (b) are a plan view and a central longitudinal cross-sectional view, respectively, showing an operation mode when the pinion rack mechanism is returned to the retracted state when the contact member is retracted.

[Explanation of symbols]

 2 screw 4 nose portion 7 striking mechanism 8 pinion rack mechanism 13 driver 17 pinion gear 26 contact member 27 engaging step portion 32 stopper piece 33 spring

Claims (1)

[Claims] 1. A screw driving machine equipped with a driver that drives a screw in a nose portion by a striking mechanism and rotates by a pinion rack mechanism with respect to the screw, usually from a tip of the nose portion. An engaging step portion is formed on a part of the contact member that is arranged so as to be retractable along the nose portion by protruding and pressing against the surface of the material to be driven, and the pinion gear shaft of the pinion rack mechanism is formed. The rotation block provided integrally supports the stopper piece so that the rotation block can be rotated to a first position for advancing above the engagement step of the contact member and a second position for retracting from the engagement step, and This stopper piece is a pinion
Before the rack mechanism is actuated, the spring is biased so that it is in the first position, and at the time of driving operation, the stopper piece is engaged with the engaging step portion of the contact member to regulate the retracting movement amount of the contact member and screw it in. A driving depth control mechanism for a screw driving machine, which is characterized in that the stopper piece is sometimes rotated in a second position in conjunction with a pinion gear.