JPH07266250A - Device for preventing feed error of connecting screw for use in thread fastener - Google Patents

Abstract

PURPOSE:To prevent the feed error of connecting screws by providing a nose part with a bit stopper perpendicular to a driver bit, and forming on the peripheral surface of the driver bit corresponding to the bit stopper an engagement portion which is engaged with and disengaged from the bit stopper. CONSTITUTION:When a nose part 3 is pressed in toward a thread fastener main body 1 while a trigger lever is not pulled, a driver bit 2 is moved forward relative to the main body. Then at least one of bit stoppers 8, 9 is engaged with a lock 12 and so the bit stoppers 8, 9 are locked to the locking wall 13 of the lock 12 of the driver bit 2 to keep the driver bit 2 from moving forword. The relative movement due to the pressing-in of the nose part 3 is therefore stopped and the feed mechanism of connecting screws (a) does not operate. It is therefore ensured that such feed error as feeding the connecting screws (a) twice in succession can be prevented.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a preventive device for preventing the occurrence of a feeding error in which a connecting screw is fed twice in a screw tightener using the connecting screw.

[0002]

2. Description of the Related Art Generally, a screw tightening machine is provided with a nose part that moves relative to the main body of the screw tightening machine, and when performing the screw tightening work, the tip of the nose part is pressed against a material to be screwed to allow relative movement. Based on this, the screw feeding mechanism provided in the nose portion operates to feed the connecting screws supplied to the nose portion one by one to the hammering portion. Such a screw feed mechanism is known, for example, from Japanese Utility Model Laid-Open No. 2-127676.

However, if, for example, the nose part is accidentally pressed against an object other than the intended member, a so-called chord sign is entered and the screw feed mechanism operates to feed a single screw. When the nose portion is pressed against the material to be screwed, the screw feed mechanism is activated again, and the second screw is further supplied to the punched-out portion of the nose portion. In this way, when two screws are fed to the embossing section, these screws are clogged in the nose section, so an extra one has to be removed, which is a troublesome work and is also removed. There was a problem that books were wasted.

[0004]

SUMMARY OF THE INVENTION It is an object of the present invention to solve the above-mentioned problems and to provide a connecting screw feeding error preventing device in a screw tightening machine which effectively prevents screw feeding when the nose portion is erroneously pressed. Is its purpose.

[0005]

In order to achieve the above-mentioned object, a device for preventing misfeed of a connecting screw according to the present invention is provided with a driver bit and a rotation driving mechanism for the driver bit inside a screw tightener main body. A screw tightening machine is provided with a nose portion that slides relative to the main body of the tightening machine in the axial direction of the driver bit, and a feed mechanism for a connecting screw is provided at the tip of the nose portion. A bit stopper that is rotatable in the direction orthogonal to the bit is provided, and the bit stopper is spring-biased toward the center of the driver bit. It is characterized in that a locking portion which is engaged with and disengaged from the bit stopper during rotation is formed.

[0006]

According to the present invention, when the nose portion is pushed into the nailing machine main body side without operating the rotary drive mechanism, the driver bit relatively moves to the nose portion side. The bit stopper is locked to the locking portion of the driver bit, and the movement of the driver bit is blocked. For this reason, the relative movement of the nose portion by pushing is prevented, and the feed mechanism for the connecting screw does not operate. Therefore, a mistake in feeding the connecting screw can be reliably prevented.

On the other hand, when the nose portion is pressed against the material to be screwed and the trigger lever is pulled while the main body of the nail driver is pushed in, the driver bit is rotated by the rotary drive mechanism, so that the bit stopper is locked during one rotation. The nose part may be moved relative to the nose part, and the connecting screw is fed by the feed mechanism, and the nose part is engaged with the tip of the driver bit in the groove of the screw head. Is struck from the tip of.

Therefore, according to the above-described feeding error prevention device, it is possible to reliably prevent the screw feeding when the nose portion is accidentally pressed against the material to be screwed.

[0009]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS FIG. 1 is a cross-sectional view of a main part of a connecting screw feeding error prevention device according to the present invention, FIG. 2 is a cross-sectional view taken along the line X--X of FIG. 1, and FIG. Aspect explanatory diagram,
FIG. 4 is a sectional view taken along the line YY of FIG.

In FIG. 1 and FIG. 2, reference numeral 1 is a screw tightener main body of the screw tightener, in which a driver bit 2 and a rotary drive mechanism are provided. The rotary drive mechanism is a well-known mechanism that drives the driver bit 2 to rotate by an air motor or the like by pulling a trigger lever (not shown) with a finger. A nose portion 3 is arranged at the front end of the screw tightener main body 1 so as to be relatively slidable in the axial direction of the driver bit 2, and a feed mechanism for a connecting screw a is provided at the tip of the nose portion 3.

Although the feeding mechanism of the connecting screw a is not shown, it is the same known mechanism as that shown in the above-mentioned Japanese Utility Model Laid-Open No. 2-126776, and is based on the relative movement of the nose portion 3 with respect to the screw tightener main body 1. By intermittently driving the feed wheel, only one connecting screw is fed toward the launch portion.

The nose portion 3 has the driver bit 2
A guide tube 4 for slidably accommodating and guiding is formed, and a pair of wall portions 5 and 6 projecting in a flange shape are formed opposite to each other at a rear end portion of the guide tube 4. The wall surfaces of these wall portions 5 and 6 are formed at right angles to the driver bit 2 and are connected via a plate-shaped connecting portion 7. By this connecting portion 7, the peripheral surface of the driver bit 2 is exposed in the space S between the opposing wall surfaces.

Next, in the space S between the facing wall surfaces, one bit stopper 8 and 9 is arranged on the opposite side with the connecting portion 7 interposed therebetween, and the bit stoppers 8 and 9 are pivoted on the support shaft 10 between the facing wall surfaces. It is pivotally supported. A compression spring 11 is arranged between one end of the bit stoppers 8 and 9 and the connecting portion 7, so that the other ends of the bit stoppers 8 and 9 always rotate in the center direction of the driver bit 2 in the guide cylinder 4. Is urged to.

By the way, the cross section of the shaft portion of the driver bit 2 is circular, but the engaging portion 12 is formed on the peripheral surface corresponding to the bit stoppers 8 and 9. The locking portion 12 is formed by notching the shaft portion in a substantially triangular cross-section with a part of the outer peripheral surface left, and forming the rear end surface as a locking wall 13 perpendicular to the outer peripheral surface of the shaft portion. It is a thing.

As described above, the bit stoppers 8 and 9 are 2
On the other hand, since the cutout surface 12a of the locking portion 12 of the driver bit 2 has three surfaces and a part of the outer peripheral surface of the shaft portion is left, both bit stoppers 8 and 9 are formed. One of the bit stoppers 9 (or 8) is engaged with the engaging portion 12 or is engaged with the engaging portion 12 (state of FIG. 2).
Either, or both bit stoppers 8 and 9 are released from the engaged state (state of FIG. 4).
Both bit stoppers 8 and 9 may be in the disengaged state, but the probability is very low, so normally at least one bit stopper 8 or 9 is engaged with the locking portion 12 as shown in FIG. It is in a matched state.

Next, the operation mode of the connecting screw feeding error preventing device having the above-mentioned structure will be described. When the nose portion 3 is pushed into the screw tightener main body 1 side without pulling the trigger lever, the driver bit is relatively moved. 2 moves forward, but at least one of the bit stoppers 8 and 9 is engaged with the engaging portion 12, so that the bit stoppers 8 and 9 are engaged with the engaging wall 13 of the engaging portion 12 of the driver bit 2. Therefore, the driver bit 2 is prevented from moving forward. For this reason, the relative movement of the nose portion 3 due to being pushed in is also prevented, so that the connecting screw feeding mechanism does not operate. Therefore, a mistake in feeding the connecting screw can be reliably prevented.

On the other hand, as shown in FIG. 3, when the nose portion 3 is pressed against the material to be screwed (not shown) and the trigger lever is pulled while being pushed into the main body 1 of the nail driver, the driver bit 2 rotates. Since it is rotated by the drive mechanism, both bit stoppers 8 and 9 may be disengaged from the locking portion 12 as shown in FIG. 4 during one rotation.
At this time, since the relative movement of the nose portion 3 becomes possible, the connecting screw is fed by the feeding mechanism, and the nose is engaged with the tip of the driver bit 2 being engaged with the groove of the screw head of the screw 14 fed to the predetermined position. It is punched out from the tip of the part 3.

Therefore, according to the above-described feeding error prevention device, it is possible to reliably prevent screw feeding when the nose portion 3 is erroneously pressed.

The shapes of the bit stoppers 8 and 9 and the engaging portion 12 of the driver bit 2 are not limited to those disclosed in the above example. For example, the locking portion 1 of the driver bit 2
The two notched surfaces 12a may be formed on two surfaces as shown in FIG. 5 (a), may be formed on four surfaces as shown in FIG. 5 (b), or may be formed as shown in FIG. 5 (c). It may be formed on six sides, or may be formed in an elliptical shape as shown in FIG. In addition, the number of bit stoppers may be one or three or more. Furthermore, the bit stopper does not have to be provided on the wall portion formed on the guide tube as in the above-mentioned example. In short, it suffices that it be provided so as to be rotatable in the direction orthogonal to the driver bit.

The bit stopper is not limited to the above example. As shown in FIG. 6 (a), the bit stoppers 8a and 9a are formed in a rod shape and are housed in a recess 14 formed continuously with the connecting portion 7 and the nose portion 3 of the guide cylinder 4, and the bit stopper 8a is provided. , 9a may be axially opposed to each other with the driver bit 2 interposed therebetween, and the compression spring 15 may urge the tips of the bit stoppers 8a, 9a toward the center of the driver bit 2. Also in this case, while the driver bit 2 makes one rotation, as shown in FIG. 2B, the bit stoppers 8a and 9a and the cutout surface 1 of the driver bit 2 are formed.
Since the engagement with 2a is released, the same operation and effect as those of the above-described example can be obtained.

[Brief description of drawings]

FIG. 1 is a cross-sectional view of a main part of a connecting screw feeding error prevention device according to the present invention.

FIG. 2 is an enlarged sectional view taken along line XX of FIG.

FIG. 3 is an explanatory view of a screw tightening operation mode by the nail driver.

FIG. 4 is an enlarged sectional view taken along the line YY of FIG.

5 (a), (b), (c), and (d) are cross-sectional views of another example of the cross-sectional shape of the locking portion of the driver bit.

6 (a) and 6 (b) are cross-sectional views showing another example of the feed error preventing device for the connecting screw in the same cross section as FIG. 2 and FIG.

[Explanation of symbols]

 1 Screw tightener main body 2 Driver bit 3 Nose part 8 Bit stopper 9 Bit stopper 12 Locking part 13 Locking wall

Claims (1)

[Claims] 1. A screwdriver main body is provided with a driver bit and a rotation driving mechanism for the driver bit, and a nose portion that slides relative to the screw fastener main body in the axial direction of the driver bit is provided. In a screw tightener provided with a connecting screw feed mechanism at the tip of the nose portion, a bit stopper rotatable in the direction orthogonal to the driver bit is provided at the nose portion, and the bit stopper is provided for the driver bit. In a screw tightener characterized in that a spring portion is biased toward the center, and a locking portion that engages and disengages with the bit stopper when the driver bit rotates is formed on the peripheral surface of the driver bit corresponding to the bit stopper. Device for preventing misfeeds of connecting screws.