JP2000266020A - Screw and screw fastening method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To prevent the impairing of fastening force caused by the enlargement of a screw hole by setting a height from a valley part of a thread near a head higher than that from a valley part of the thread at a lower part of a barrel part. SOLUTION: To drive a point 24 of a screw 20 to a sheet metal by a piston rod of an air driver, a driving hole and a recess around the driving hole are formed on the sheet metal. By rotating the screw 20 after the screw 20 is driven, a shank diameter is enlarged into the taper shape by a point taper part 24c, which increases the fastening resistance, further the fastening resistance is slightly lowered at a parallel screw part 24a of a small diameter from the point taper part 24c, and the fastening resistance is increased and then lowered at a barrel part 23 from the taper part. When an outer diameter enlargement part 27 reaches the neighborhood of an edge of the driving hole after the fastening of the barrel part 23, an outer diameter of a thread 26 and a shank diameter of the barrel part 23 are increased, and the stopping of the work is urged by the fastening resistance and the increases of a time. The impairing of the screw fastening force caused by the enlargement of the screw hole to be more than a shank diameter of the screw, 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 screw for screwing sheet metals together with an air driver or the like using compressed air and a method for fastening the screw.

[0002]

2. Description of the Related Art Conventionally, there has been known an air driver that drives a piston rod with compressed air to drive a screw into an object, and then rotates a screwdriver provided at the tip of the piston rod to screw the screw. FIG. 7 shows a screw to be screwed with the air driver.

The screw 1 has a neck 3 and a trunk 4 formed at the lower part of a head 2 to which a "+" blade at the tip of the driver fits, and the tip of the trunk 4 is sharply pointed. It has a different shape. A screw thread 5 is spirally formed from the body part 4 to the neck part 3, and the outer shape of the screw thread 5 and the thickness from the body part 4 to the neck part 3 are formed to be substantially constant. .

When a wall panel 6 of a building shown in FIG. 8 is formed by using the screws 1, C
The horizontal frame 8 made of a mold steel plate is covered, and the screw 1 is screwed from above the horizontal frame 8 with an air driver.

[0005] In the air driver for screwing the screw 1, a piston rod is disposed in an air cylinder into which compressed air is fed, and a "+" shaped driver blade is formed at the tip of the piston rod. The final stage gear is mounted on the tip side of the piston rod. The piston rod and the final stage gear are made rotatable and reciprocable by the key and key groove.
The gear at the last stage is in mesh with a gear mechanism that transmits rotational torque. The first stage gear of this gear mechanism is fixed to the output shaft of the air motor. The air motor has a motor housing into which compressed air obtained by reciprocating a piston rod is introduced, an output shaft is rotatably held in the motor housing, and blades for receiving the compressed air introduced into the output shaft are provided. I have.

When the piston rod is located on the cylinder head side, the screw 1 is located in front of the blade portion, and the piston rod is rotated by the gear at the last stage, screwing is completed, and the screw 1 returns to the cylinder head side. Sometimes the next screw 1 is supplied. That is, below the position where the screw 1 is supplied,
A screw wound body in which a large number of screws 1 are bound in a substantially parallel manner with a tape or the like is arranged, and each time the piston rod is returned to its initial position after the completion of screwing of the piston rod, the screw 1 is supplied in front of the blade portion. I have.

[0007]

However, in the case of the conventional screw 1, the thickness of the neck 3 and the body 4 at the lower part of the head 2 and the outer diameter of the screw thread 5 are constant from top to bottom. Therefore, if the screw 1 is tightened with an air driver or an electric driver, the resistance during rotation is low, and the area for adjusting the torque is narrow. For this reason, as shown in the tightening time t1 in FIG. 6, the screwing is instantaneously terminated, and in the case of screwing the vertical frame 7 and the horizontal frame 8, the screw hole of the double plate is enlarged. A so-called screw stutter in which the fastening force of the screw 1 cannot be obtained may occur.

Further, in the case of the conventional screw 1, as shown in FIG. 9, after the vertical frame 7 and the horizontal frame 8 are screwed and the gypsum board 9 (see FIG. 10) is attached, the head of the screw is Since the projecting amount from the sheet metal is large, the horizontal frame 8
Between the gypsum board 9 and the gypsum board 9
There was a problem that could be 0.

The screw and the method of fastening the screw according to the present invention have been made in view of such a problem. When a metal plate is screwed to each other with a driver using power, a screw hole is formed and enlarged. By doing so, it is possible to prevent the screw from significantly reducing the force with which the sheet metal is fastened to the head side. An object is to minimize the amount of protrusion.

[0010]

According to the present invention, there is provided a screw according to the present invention, wherein a screw is formed under a head having a groove into which a blade portion of a driver fits. In a screw provided with a torso portion, and the lower end of the torso portion is formed at an acute angle, the height from the root of the thread is lower than the depth of the lower part of the torso near the head. The height is set to be larger than the height.

In the screw according to the second aspect of the present invention, a body having a thread is provided below a head having a groove in which the blade of the driver fits, and the lower end of the body has an acute angle. In the screw formed in the above, the thickness of the body located at the root of the screw thread is set to be larger than the thickness of the body located at the root of the screw thread at the lower part of the body near the head. It is characterized by having.

In the screw according to the third aspect of the present invention, a threaded body is provided below a head having a groove in which the blade of the driver fits, and a lower end of the body is formed at an acute angle. Wherein the height from the root of the thread is set to be greater than the height from the root of the thread at the lower part of the body near the head, and the root of the thread is The thickness of the torso located in the portion is set to be larger than the thickness of the torso located in the thread valley below the torso near the head.

A screw according to a fourth aspect of the present invention is the screw according to the first to third aspects, wherein a tapered portion whose diameter gradually increases from the thickness of the body portion is provided between the head portion and the screw thread. It is characterized by being formed.

According to a fifth aspect of the present invention, there is provided a method of fastening a screw to a sheet metal using a driver driven by compressed air or electricity. After fitting the blade portion of the driver to the head and driving the lower end of the screw into a sheet metal, rotate the driver in the direction of fastening the screw, and after the upper part of the body enters the sheet metal, Rotational resistance to rotation of the driver is increased until the head contacts the sheet metal.

[0015]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, a screw according to an embodiment of the present invention will be described with reference to the drawings.

FIG. 1 shows a screw 20 according to this embodiment.
FIG. 2 shows the shape of the head 21 of the screw 20. A neck portion 22 is formed at a lower portion of the head portion 21,
The neck portion 22 is formed in a truncated cone shape having a tapered cross section with a small diameter at the lower part and a large diameter at the upper part.

The lower part of the neck 22 is a trunk 23, and the trunk 2
A tip portion 24 for driving a sheet metal is formed below 3. The distal end portion 24 is formed at the lowermost end so as to first enter the object when the screw 20 is driven, and is formed on the upper end of the distal end taper portion 24b. A small-diameter parallel screw portion 24a having a shaft diameter smaller than the diameter of the shaft, which is smaller in thickness, and a body portion 24 formed above the small-diameter parallel screw portion 24a;
And a tapered portion 24c that expands to the shaft diameter of. The leading end portion 24 has a thread 25 for entry, and the body portion 23 has a large thread 26 following the thread 25.

In the vicinity of the neck 22, the thread 26 is formed as an enlarged outside diameter portion 27 whose outside diameter is gradually increased, and the shaft diameter serving as the root of the thread 26 is also increased in the outside diameter enlarged portion 2.
7 is enlarged to form a shaft diameter enlarged portion 28.

The outer diameter enlarged portion 27 is set in a region where about 2 to 5 screw threads 26 are formed at the upper end of the body portion 23, and the outer diameter is higher than the lower outer diameter of the outer diameter enlarged portion 27. Is set to be large, and the outer diameter of the peak portion of the outer diameter enlarged portion 27 is gradually increased from the lower portion to the upper portion.

The enlarged shaft diameter portion 28 is also formed so as to gradually increase from the lower portion to the upper portion within the range of the height of the outer diameter enlarged portion 27.

In this embodiment, both the outer diameter enlarged portion 27 in which the outer diameter of the thread 26 gradually increases and the shaft diameter enlarged portion 28 in which the shaft diameter gradually increases are formed on the upper portion of the body portion 23. However, only one of them may be used. Further, the width of the crest ridge line at the vertex of the screw thread 26 may be enlarged as going from bottom to top. Further, the pitch of the threads 26 may be changed so that the pitch of the threads 26 becomes smaller in the area of the outer diameter enlarged portion 27, for example. Further, a streak extending in the axial direction of the body portion 23 may be formed at the crest ridge line at the apex of the screw thread 26.

As shown in FIGS. 2 and 3, the head 21 has
A cross groove 29 into which the driver is fitted is formed, and the cross groove 29 is formed deep in the neck 22. The bottom of the cross groove 29 is formed up to near the upper end of the body 23.

Next, a description will be given of a case where the screw 20 is used to screw into a sheet metal by an air driver. In this embodiment, the air driver is an air driver that rotates the piston rod after advancing the piston rod with conventionally known compressed air. A blade portion of a driver for turning a screw is formed at the tip of the piston rod.

When the screw 20 is screwed in with an air driver, the screw 20 is set near the end of the piston rod opposite to the cylinder head. When the screw driver of the air driver is applied to the sheet metal and the trigger of the air driver is pulled, the compressed air is introduced into the air cylinder of the air driver, the piston rod retreats from the cylinder head, and is provided at the tip of the piston rod. The blade of the screwdriver fits into the cross groove of the head 21. The piston rod further retreats from the cylinder head by the supply of the compressed air, and strikes the tip 24 of the screw 20 into the sheet metal 30 (see FIG. 5).

When the piston rod drives the distal end portion 24 of the screw 20 into the metal plate 30, a driving hole 31 is formed in the metal plate 30, and a concave portion 32 is formed by recessing around the driving hole 31.

After the driving of the screw 20, the piston rod starts rotating, and the thread 26 of the screw 20 penetrates the sheet metal 20 while expanding the driving hole 31.

FIG. 6 shows the change in the tightening time and the tightening resistance during the rotation of the screw at this time. Compared to the change in the conventional tightening time and the change in the tightening resistance, the maximum value of the conventional tightening resistance was Tr1 by using the screw shape of the embodiment. Can be obtained, and a screw tightening time t2 longer than the conventional screw tightening time t1 can be obtained. As a result, the region where the torque of the driver can be controlled is widened, and the occurrence of so-called screwback can be sufficiently controlled. In addition, even when manually closed, screw fools can be prevented more than conventional screws.

That is, after the screw 20 is driven,
When is rotated, the shaft diameter increases in a tapered shape by the tapered end portion 24b, so that the tightening resistance increases.
When the small-diameter parallel screw portion 24a is reached from the tip tapered portion 24b, the tightening resistance is slightly reduced, and the tapered portion 24c is formed.
From the torso 23, the tightening resistance increases and then decreases. When the outer diameter enlarged portion 27 reaches the vicinity of the edge of the driving hole 31 after the tightening of the body portion 23, the outer diameter of the thread 27 increases, and the shaft diameter of the body portion 23 increases.

For this reason, the maximum value Tr2 of the tightening resistance
Increases from the conventional maximum value Tr1, and the tightening time t2 increases from the conventional tightening time t1, so that an increase in the tightening resistance becomes apparent due to a decrease in the rotational speed of the driver and a prolonged tightening time. This can prompt the operator to release the driver.

After the rotation speed of the driver is reduced, the neck 22
Contact with the inner surface of the concave portion 32, the tightening resistance of the driver further increases, the number of rotations of the driver decreases, and the tightening time increases, so that it is more clear that the operator has a time to release the driver from the screw. Can be sensed and driver control becomes easier.

If the driver releases the trigger when the rotational force of the driver further decreases significantly and the tightening time becomes longer, the neck 2
2 fits in the recess 32, and the head 21 of the screw 20 is located at the average level of the sheet metal 30,
The amount of protrusion from the projection is significantly reduced.

Therefore, when a plate material such as a gypsum board or a panel is mounted on the sheet metal 30, these plate materials and the plate metal 30
Can be minimized or eliminated as much as possible, and a high-quality wall panel in which the frame and the gypsum board, panel, and the like are tightly assembled can be manufactured.

[0033]

According to the screws of the first to fourth aspects of the present invention and the screw fastening method of the fifth aspect, a bend is generated on the sheet metal side when the screw is driven, and the lower end of the screw is inserted into the sheet metal. It is. Next, when the driver is rotated, the screw is screwed into the sheet metal. In the process of screwing the screw into the sheet metal and entering, the outer diameter of the thread at the neck or the thickness of the valley of the thread increases, so that the edge of the screw hole of the sheet metal becomes the crest and the valley of the thread. The tightening resistance increases and the tightening time increases, so that when operating a driver using power, the operator can easily perform the operation of stopping the application of torque by removing the driver, and the screw hole is It is possible to prevent a so-called screw stupid that the screw tightening force is lost due to expansion beyond the shaft diameter of.

Further, since the screw according to the fourth aspect of the present invention is formed with a tapered portion at the neck, immediately before the head comes into contact with the sheet metal, the tightening resistance is further increased and the rotational speed of the driver is reduced. And the tightening time becomes longer. Therefore, in the operation of stopping the application of the torque by which the driver of the driver uses the power to separate the driver from the screw, this operation can be performed more reliably, and the depression around the screw hole when the screw is driven into the sheet metal is formed. Since the tapered portion fits in, the amount of protrusion of the screw head from the average height of the sheet metal is reduced, and when mounting a plate material such as a gypsum board or a panel on the sheet metal, the gap between these plate materials and the sheet metal It can be minimized or eliminated as much as possible.

[Brief description of the drawings]

FIG. 1 is a diagram showing a side shape of a screw according to an embodiment of the present invention.

FIG. 2 is a plan view showing the shape of the head of the screw in FIG. 1;

FIG. 3 is a partial cross-sectional view passing through the center of the cross groove in FIG. 2;

FIG. 4 is an enlarged view of a portion near a neck portion of the screw in FIG. 1;

FIG. 5 is an enlarged view around a screw hole when the screw in FIG. 1 is screwed into a sheet metal;

FIG. 6 is a graph showing changes in rotation speed and rotation resistance when the screw in FIG. 1 is screwed into a sheet metal.

FIG. 7 is a diagram showing a side shape of a conventional screw.

FIG. 8 is a view showing a skeleton of a frame of a wall panel.

9 is a partial cross-sectional view when the vertical frame and the horizontal frame in FIG. 8 are fastened with screws.

FIG. 10 is a partial cross-sectional view showing a state where a gypsum board is attached to the frame of FIG. 8;

[Explanation of symbols]

 REFERENCE SIGNS LIST 20 screw 21 head 22 neck 23 torso 24 screw tip 25 tip screw 26 torso 27 outer diameter enlarged part 28 shaft diameter enlarged part 29 cross groove

Claims (5)

[Claims] 1. A screw having a threaded body provided below a head having a groove into which a blade of a driver fits, wherein a lower end of the body is formed at an acute angle. A screw, wherein a height of the screw thread from a valley portion is set to be larger in the vicinity of the head portion than a height of the lower portion of the body portion from a thread valley portion. 2. A screw having a threaded body provided below a head having a groove into which a blade of a driver fits, wherein a lower end of the body is formed at an acute angle. A screw characterized in that the thickness of the body located at the thread valley is set to be larger than the thickness of the body located at the thread valley below the body near the head. . 3. A screw provided with a threaded body below a head having a groove into which a blade of a driver fits, wherein the lower end of the body is formed at an acute angle. The height from the root of the thread is set to be larger than the height from the root of the thread at the lower part of the trunk near the head, and the thickness of the trunk located at the root of the thread is set. Saga,
The screw is characterized in that it is set to be larger than the thickness of the body located in the thread valley below the body near the head. 4. A screw according to claim 1, wherein a tapered portion whose diameter gradually increases from the thickness of the body is formed between said head and said screw thread. Screw. 5. A method for fastening a screw to a sheet metal according to claim 1 using a driver powered by compressed air or electricity, wherein a blade portion of the driver is fitted to the head. After the lower end of the screw is driven into the sheet metal, the driver is rotated in the direction of fastening the screw, and the upper part of the body enters the sheet metal until the head comes into contact with the sheet metal. A method for fastening a screw, characterized by increasing a rotational resistance against rotation of the driver.