JPH09201775A - Driver for screw driving machine - Google Patents

Abstract

PROBLEM TO BE SOLVED: To enhance the probability that, when the bit part of a driver is driven, it runs into the cross grooves of the driving screw, by forming the maximum width of the base part of the end conical part smaller than the minimum width of the central part of the opening end of the cross groove of the driving screw. SOLUTION: The shaft part of a driver is in a noncircular shape, and cross blades 3 are formed in the bit part 2 at its end, and the end conical part 5 whose vertex 4 is pointed is formed at the further end part of the cross blades 3. The angle α formed by the conical surface 6 of the end conical part 5 placing the axial center line P therebetween is made to be 110deg. or less. Further, the maximum width W of the base part of the end conical part 5 is formed so as to be less than the minimum width w (not shown) at the center of the opening end of the cross groove 8 (not shown) of a driving screw. The end conical part 5 of the driver becomes easily being slid into the cross groove 8 of the driving screw, and the probability in running into the cross groove 8 can be enhanced.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a screwdriver that rotates a screw driving machine after striking a driving screw supplied to a predetermined position of a screw driving machine.

[0002]

2. Description of the Related Art Generally, a screwdriver has a striking mechanism for striking a driver and a rotary drive mechanism for rotating the driver. First, the striking mechanism strikes the driving screw with the driver to the driving screw supplied to the nose portion. After that, the driver is rotated by the rotary drive mechanism to screw in the driving screw, which is used when the gypsum board is fixed to a thin iron plate.

[0003]

However, as shown in FIG. 9, the most distal end of the bit portion of the conventional driver has a truncated cone shape, the top portion 10 is formed flat, and the conical surface following the cone portion has a conical surface. The angle a between the center is also 1
Since it was as large as about 44 degrees, when the driving screw hits when it is slightly displaced from the axis of the driver, the top may collide with the opening edge of the cross groove 12 of the screw head of the driving screw 11. In such a high-speed collision, the entire tip operates in the same way as a flat surface, and the tip does not easily slip into the cross groove 12 of the screw head. Either the phenomenon is that the cross-shaped groove of the part is driven in a state where it does not engage, or the driving screw is driven in an inclined state. In both cases, this is a phenomenon that occurs when the tip of the driver does not engage with the cross groove of the driving screw, and in the former case, rotational torque is not transmitted from the bit to the screw, causing idling. In the latter case, there is a problem in that, in addition to causing excessive driving, a stupid hole is opened in the light sky (thin iron plate), and a predetermined holding force cannot be obtained.

The present invention solves the above problems, increases the probability that the bit portion of the driver jumps into the cross groove of the driving screw at the time of impact, and improves the reliability of the engagement between the driver and the driving screw. The problem is to provide a machine driver.

[0005]

In order to solve the above-mentioned problems, a screwdriver for a screw driving machine according to the present invention is screwed and rotated after striking a driving screw supplied to a predetermined position of the screw driving machine. In the driver, the tip of the bit portion of the driver forms a conical tip cone with a sharp tip, and the conical surface of the tip cone has an angle of 110 degrees or less with respect to the axis center. The maximum width of the base portion of the conical tip portion is smaller than the minimum width of the central portion of the open end of the cross groove of the driving screw.

[0006]

1 is a side view of a driver for a screw driving machine, the base of which is a striking piston (which is slidably housed in a striking cylinder that constitutes a striking mechanism of the screw driving machine). (Driven by compressed air), the middle part is fixed to the center of the gears that make up the rotary drive mechanism. 2 is a sectional view taken along line XX of FIG.
FIG. 3 is an enlarged view of the bit portion of the driver, FIG. 4 is a front view of the shaft portion of the driver seen from the top of the tip of the bit, and FIG.
4 is a sectional view taken along line YY of FIG. 4, and FIG. 6 is a sectional view taken along line XX of FIG.

In the above figure, the shaft portion 1 of the driver has a non-circular shape, a cross blade 3 is formed on the bit portion 2 at the tip thereof, and the tip portion 4 of the cross blade 3 has a sharp top portion 4 at the tip. The part 5 is formed. However, technically, it is unavoidable that an extremely small flat portion having a diameter of 0, 2 mm is formed on the top portion 4, so it is preferable to limit it to 0 as much as possible.

Next, an angle α formed by the conical surface 6 of the tip conical portion 5 with respect to the axis P is formed to be 110 degrees or less.

Further, the maximum width W of the base portion of the tip conical portion 5 is formed to be smaller than the minimum width w of the central portion of the opening end of the cross groove 8 of the driving screw 7 shown in FIG. In this case, since the cross groove 8 is formed in a cross shape, the minimum width w means the width between the corner portions 9 and 9 facing each other in the central portion.

According to the above driver configuration, since the tip apex 4 of the bit portion 2 is formed sharply, the tip apex 4 of the bit portion 2 is screwed when the driving screw 7 is inclined as shown in FIG. When colliding with the opening edge of the cross groove 8 of the head, the top portion 4 is guided to the cross groove 8 side as shown by an arrow and easily slips even if the head 4 is conventionally separated from the cross groove 8. .

By the way, even if the apex 4 is formed sharply, if the angle α formed by the conical surface 6 with respect to the shaft center P is the same as in the conventional case, a driver driven at high speed is the head of the driving screw 7. Since the conical surface 6 of the tip conical portion 5 acts almost like a flat surface when it hits the cross groove 8, it causes the driving screw 7 to be tilted and locked. However, it has been found that the smaller the angle α formed by the conical surface 6 with respect to the axial center P, the higher the rate at which the bit meshes with the cross groove 8. As a result of the experiment, it was found that when the angle α of the conical surface 6 becomes 110 degrees or less, the tip conical portion 5 of the driver easily slips into the cross groove 8 of the driving screw 7. Therefore, the bit part 2 of the driver
The tip conical portion 5 is easily introduced into the cross groove 8.

Further, the tip conical portion 5 is formed so as to be wider toward the base side (upper side in the figure), and the maximum width W thereof is smaller than the minimum width w of the open end of the cross groove 8 of the screw 7. Since it is formed so as to be smaller, the probability that the cross blade 3 jumps into the head cross groove 8 of the driving screw 7 becomes high.

Therefore, according to the driver having the above-described structure, the probability that the bit portion 2 of the driver jumps into the cross groove 8 of the driving screw 7 at the time of impact is increased, and the reliability of the engagement between the driver and the driving screw 7 can be improved. it can.

By making the cross groove of the driving screw deeper and increasing the minimum width of the opening end, the probability that the driver and the cross groove of the driving screw mesh with each other can be increased more reliably. , The torque of the driver can be efficiently transmitted.

[Brief description of drawings]

FIG. 1 is a side view of a driver for a screwdriver according to the present invention.

FIG. 2 is a cross-sectional view taken along line XX of FIG.

FIG. 3 is an enlarged view of a bit portion of the driver.

FIG. 4 is a front view of the shaft of the driver as seen from the top of the tip of the bit.

5 is a cross-sectional view taken along the line YY of FIG.

FIG. 6 is a sectional view taken along line ZZ in FIG.

FIG. 7 is a plan view of the head of a driving screw.

FIG. 8 is an explanatory diagram of how the driver is used.

FIG. 9 is an explanatory view of a usage state of a conventional driver.

[Explanation of symbols]

 W Maximum width of conical part w Minimum width of cross groove 2 Bit part 4 Top part 5 Tip conical part 6 Cone surface 7 Driving screw 8 Cross groove

Claims (1)

[Claims] 1. A driver for screwing and rotating after hitting a driving screw supplied to a predetermined position of a screw driving machine, wherein the tip of the bit portion of the driver is a conical tip cone with a sharp top. And the angle formed by the conical surface of the tip conical portion with respect to the axial center is 110 degrees or less, and the maximum width of the base portion of the tip conical portion is the central portion of the open end of the cross groove of the driving screw. A driver for a screwdriver, which is formed to have a width smaller than the minimum width of.