JPH0531289Y2 - - Google Patents

Description

[Detailed Description of the Invention] [Industrial Field of Application] The present invention relates to a sealing device provided under the head of a self-threading screw.

[Conventional technology]

BACKGROUND ART A self-drilling screw is conventionally known that self-drills and threads a workpiece without a prepared hole through a drill portion provided at its tip. In addition, for the pilot hole pre-formed in the workpiece,
Tapping screws that self-thread while tapping are known.

These self-threading screws are particularly useful in the construction field when attaching an attachment such as a panel to an adherend, since there is no need to form a female thread in advance on either the adherend or the attachment, and it can be machined on site. It is widely used because it enables the simple operation of screwing screws into objects.

By the way, when attaching an object such as the above-mentioned panel to an adherend outdoors, if the self-threading screws are simply used to drill holes and screw them in, rainwater, etc. will drain from the drilled holes along the screws. There is a problem of infiltration. For this reason, conventionally, an annular packing is provided below the head of the screw. That is, when the screw is screwed in, the packing is pressed between the surface of the attachment and the lower surface of the screw head, thereby creating a seal.

[The problem that the idea aims to solve]

The above-mentioned self-threading screws are usually screwed into a workpiece while being subjected to a powerful rotational torque by a power tool such as an electric tool or an air tool, so it is difficult to stop the screw at a predetermined screwing end position. Usually, the vehicle is stopped at an over-approach position that exceeds a predetermined position. In other words, at the screw-in end position, the packing is compressed excessively between the surface of the workpiece and the lower surface of the screw head beyond the designed value, and is deformed so as to protrude significantly outside the screw head. However, when the packing is excessively compressed in this way, there is a problem in that the packing deteriorates early and the intended watertight effect is diminished.

In this regard, although it is not a self-threading screw, there is a known screw that is provided with a gasket on the lower side of the screw head and provided with a stopper means to prevent excessive compression of the gasket when screwing the bolt into a nut using a power tool. be.

For example, Japanese Utility Model Application No. 60-180818 provides a downward skirt around the outer periphery of the bolt head, and the skirt constitutes a stopper means that comes into contact with the workpiece during screwing.

However, although this technique of constructing the stopper means with a skirt works well as far as general bolts are screwed into nuts, it is not suitable for self-threading screws such as drill screws of the present invention. be.

That is, as shown in FIG. 6, the drill screw self-adheres into workpieces 18a and 17a that do not have pilot holes in advance while drilling holes with the drill portion 5a at the tip of the shank. , as shown, the shank is often screwed under an axis Y that is inclined with respect to the normal X of the workpiece.

When the drill screw is screwed toward the tilt axis Y, the skirt portion (stopper means 13a) located at the outermost periphery of the head is largely tilted and comes into contact with the workpiece 18a. It is not possible to press the entire part uniformly, and the packing 1
An uncompressed portion 12b is generated in a part of 2a. Moreover, the stopper portion 13a, which is largely tilted,
Since the stopper means 13a is strongly pressed against the workpiece 18a while rotating, the stopper means 13a is easily destroyed. In particular, the head is covered with synthetic resin,
In this structure in which a skirt portion is formed on the covering body, the synthetic resin skirt portion is easily destroyed, which not only fails to achieve the intended purpose but also greatly reduces the appearance of the drill screw after tightening. It will be damaged.

[Means to solve the problem]

The present invention provides a sealing device for a self-threading screw such as a drill screw that solves the above-mentioned problems.The device is configured to include a head having a tool engaging part, and a sealing device that connects the head from the drill part at the tip. In a self-threading screw formed by integrally connecting a shank portion with a thread facing toward the shank portion: a substantially annular seal portion is formed on the lower surface of the head portion, and a substantially annular seal portion is formed on the lower surface of the seal portion; A substantially annular packing made of an elastic material is disposed on the shank; a neck portion located on the inner periphery side of the seal portion and protruding from the outer periphery of the proximal end of the shank portion is integrally formed with the shank portion; a stopper portion is formed at the neck portion, and the lower surface of the stopper portion is positioned between the seal portion and the lower surface of the seal; the outer diameter of the stopper portion is gradually increased from the stopper portion toward the seal portion on the outer periphery of the neck portion; The point is that a guide tapered surface is provided.

〔Example〕

Embodiments of the present invention will be described in detail below based on the drawings.

(First Example) In the first example shown in FIGS. 1 to 3,
A self-threading screw 1 such as a drill screw has a head 3 made of synthetic resin on a metal screw body 2 that self-threads into a workpiece.

The screw body 2 includes a drill portion 5 at the tip of the shank portion 4, and a neck portion 6 having a slightly larger diameter than the shank portion 4 is formed at the base end of the shank portion 4. It is equipped with a small head 8 formed in series from a flange-like seat 7 formed in the shank part 4, and a drill part 5 at the tip is provided on the outer periphery of the shank part 4.
A screw thread 9 is formed extending from the base end to the neck portion 6, and these threads are integrally formed from one metal material.

The head 3 made of synthetic resin is molded from a resin material reinforced by mixing nylon or other strong synthetic resin with short fibers such as glass fiber or carbon fiber, and is made of a resin material reinforced by mixing short fibers such as glass fiber or carbon fiber. The base end of the shank portion 4 including the outer periphery, the seat 7 and the small head 8 is inserted into a mold and then injection molded. Therefore, this synthetic resin head 3 is integrally formed with a seat 10 that covers the small head 8 of the screw body 2 and the seat 7 of the screw body 2, and further includes a seat 10 that covers the seat 7 of the screw body 2. A guide sleeve 11 that covers the outer periphery of the neck portion 6 is integrally formed in a series. As a result, the metal screw main body 2 and the synthetic resin head 3 are in an integral relationship in the axial and circumferential directions.

The lower surface of the seat 10 of the synthetic resin head 3 constitutes an annular seal portion 12, and the lower surface of the neck portion 6 located on the inner peripheral side of the seal portion 12 constitutes a stopper portion 13. An annular packing 14 in the part 12
The gasket 14 is integrally formed of an elastic material such as rubber or elastomer, and has an annular thick wall portion 1 located on the lower surface of the seal portion 12.
5, and an annular thin portion 16 extending in a rib shape from the inner peripheral portion of the thick portion 15. That is, the cross-sectional shape of the packing 14 is vertically symmetrical with respect to the thickness center line of the thin wall portion 16. The thick portion 15 has an inner diameter that is fitted onto the guide sleeve 11, and the thin portion 16 has an inner diameter that approximately matches the outer diameter of the shank portion 4 of the screw body 2 (i.e., the root diameter of the thread 9). It is said to belong to Therefore, by inserting the screw body 2 into the packing 14 through the elastic deformation of the thin wall portion 16, the packing 14 is attached to the underside of the sealing portion 12, and in this state,
Since the thin portion 16 contacts the lower surface of the neck portion 6 and engages with the thread 9, the packing 14 does not move toward the distal end of the screw body 2 and does not fall off. At this time, if the inner diameter of the thin wall part 16 is made slightly smaller than the outer diameter of the shank part 4 (the root diameter of the thread 9), the thin wall part 16 will elastically hold the shank part 4 and prevent the packing 14 from moving loosely. It can be prevented. Note that when installing the packing 14, the shank portion 4 of the screw body 2
Since the outer periphery of is formed in a spiral shape by the thread 9, it engages with the thread 9 and seals the seal portion 12 as described above.
The packing 14 attached to the lower side of the guide sleeve 11 is not always set concentrically with the guide sleeve 11. For this reason, as shown in the second figure, the guide sleeve 11 has a tapered surface whose outer circumferential surface reaches downward and has a small diameter, so that when the screw 1 is screwed into the workpiece as described later, Patsukin 14
The guide sleeve 11 is designed to smoothly enter the inner peripheral part of the thick wall part 15.

The synthetic resin head 3 and the small head 8 of the screw body 2 each form socket trench engaging portions 3a and 8a whose outer peripheries are polygonal. In the illustrated example, the socket trench engaging portion 3a of the synthetic resin head 3 is formed in a hexagonal shape, and the socket trench engaging portion 8a of the small head 8 is formed in the aforementioned engaging portion 3a.
It is formed into a roughly similar hexagon that is smaller than the . Further, the small head 7 has a driver engagement groove 8b such as a minus groove or a plus groove formed at the top.

According to the self-threading screw based on the first embodiment, when attaching the attachment 18 such as a panel to the attachment 17, a prepared hole and a female thread are formed in advance in both the attachment and the attachment. There is no need to
The screws 1 are forcibly screwed into these workpieces on site. That is, the self-threading screw 1 is inserted into the tip drill portion 5.
If the screw 1 is placed in contact with the workpiece and the synthetic resin head 3 of the screw 1 is engaged with a socket trench attached to a power tool or air tool and rotated, the drill part 5 will be protected from the attached object. A hole is made to reach and penetrate the kimono, and the shank part 4 that continues to enter the kimono taps the hole with the thread 9 and screws through the hole, and the screw 1 screwed into the kimono fixes the attachment to the object. During this spiral movement, the synthetic resin head 3 is made of short fiber reinforced resin as described above and has excellent crush resistance and abrasion resistance, so that the engaging portion 3a
firmly engages with the socket trench, and there is little risk of idle rotation due to crushing. By the way, in the unlikely event that the engaging portion 3a of the synthetic resin head 3 is crushed during the screwing process and becomes idle relative to the socket trench, the synthetic resin head 3 should be broken with a hammer or the like. Then, by removing the broken synthetic resin head 3, the small head 8 is exposed. Then, by engaging a small-sized socket trench with the socket trench engaging portion 8a formed in the small head 8 of the exposed metal screw main body 2 and reversing the wrench, the screw in the mid-screwing state is removed. 1 can be returned and extracted from the workpiece. In addition, if the worker does not have a small socket trench,
All you have to do is engage the driver in the driver engagement groove 8b of the small head 8 and reverse the rotation.

When the screw 1 is completely screwed into the workpiece, the thick part 15 of the gasket 14 is compressed and brought into close contact with the surface of the workpiece (the attachment 18 on the front side), and the workpiece is completely screwed into the workpiece. To provide a watertight seal between the surface of an object 18 and a sealing part 12. Therefore, when the attachment 18 is attached to the adherend 17 outdoors using the self-threading screw 1 of the present invention, rainwater etc. will not enter between the hole of the workpiece and the shank portion 4 of the screw, and the screw At the same time as screwing step 1 is completed, watertight treatment is performed.

By the way, when screwing in, self-threading screws
As mentioned above, since the workpiece is screwed into the workpiece while being subjected to a strong rotational torque by a power tool such as an electric tool or an air tool, it is difficult to stop at the specified screwing end position and the screwdriver cannot exceed the specified position. It is usually stopped at the over-approach position. In this regard, according to the first embodiment of the present invention, as shown in FIG.
5 is compressed to a certain extent, the thin part 16 continues to be compressed.
comes into contact with the surface of the workpiece (attachment 18) and is compressed by the stopper part 13 of the neck part 6 to relieve the impact of the stopper part 13 on the workpiece,
At the screw-in end position where the screw 1 is further screwed in, the thin wall portion 16 is compressed between the stopper portion 13 and the surface of the workpiece until it reaches the compression limit, thereby preventing further excessive screw-in of the screw 1. Then, while the thin wall portion 16 is compressed to the compression limit, the thick wall portion 15 is compressed by a predetermined design value L between the seal portion 12 and the surface of the workpiece. Therefore, the thick portion 15 of the packing 14 can suitably provide a watertight seal between the seal portion 12 and the surface of the workpiece while maintaining appropriate elasticity.

Therefore, as described above with respect to the conventional example (FIG. 6), excessive screwing is prevented by the stopper portion 13, in which the workpiece is often inserted along the axis Y that is inclined with respect to the perpendicular X of the workpiece. However, according to the present invention, the stopper part 13 has a small diameter near the shank part 4 on the inner peripheral side of the seal part 12, so that the stopper part 13 has a smaller diameter than the inclined axis Y. The amount of inclination deviation is relatively small. Therefore, the uncompressed portion of the packing as described above in the conventional example does not occur, and the packing 12 can be compressed almost uniformly over the entire packing. Moreover, the stopper part 1
3 is firmly formed by the neck part 6 integrated with the metal screw body 2, so it will not be easily damaged, and furthermore, the shank part 4 has a small diameter as described above.
Since the amount of inclination deviation is small, destruction of the stopper portion 13 is also prevented from this point of view.

(Another embodiment of the stopper portion) In FIG. 4, the screw 1 has a head portion 20 with a seat integrally formed at the base end of the shank portion 4. Therefore, it does not have a synthetic resin head like the first embodiment. The head 20 forms a seal portion 12 on the lower surface of the seat, and a neck portion 21 that projects downward from the inner peripheral portion of the seal portion 12. This neck portion 21 has an outer peripheral surface formed into a tapered surface that reaches downward and has a small diameter, thereby forming a guide portion 11b, and a lower surface of the neck portion 21 forming a stopper portion 13.

(Another embodiment of the packing) In FIG. 5, the packing 14 includes an annular thick part 15a disposed below the seal part 12 formed by the synthetic resin head 3, and the thick part 15a. 15a
It is formed to have an L-shaped cross section with an annular thin wall portion 16 extending in a rib shape from the lower end of the shank portion 4 to the inner peripheral side, and the thin wall portion 16a is disposed below the stopper portion 13 at the base end of the shank portion 4. In addition to this embodiment, the seal 14 may be constructed of an O-ring that is simply disposed below the seal portion 12. still,
5 does not show the guide sleeve 11 on the outer periphery of the neck part constituting the stopper part 13 in order to show an embodiment of the packing. A guide sleeve 11 similar to the above is provided.

(Other Examples) In each of the above embodiments, the seal portion 12 and the packing 14 were explained as being annular.
Unless the required watertightness is strict, it does not have to be a complete annular shape, but may be approximately annular, for example, by cutting a part of the circumference of the packing 14.

[Effect of idea]

As a result of the above-described structure of the present invention, when sealing after screwing is performed using the packing arranged in the sealing part below the head of the screw, the seal is formed integrally with the shank part 4 on the outer periphery of the proximal end of the shank part 4. Neck 6,
12, a stopper part 13 is formed on the lower surface of the neck, and the lower surface of the stopper part 13 is positioned between the seal part 12 and the lower surface of the seal 14, so that the stopper part 13 It is possible to reliably prevent the screw from being excessively screwed in even though it is subjected to a strong rotational torque, and to compress the packing 14 by a predetermined design value between the seal portion 12 and the surface of the workpiece at the screwing end position. It is possible to extend the life of the packing 14 and improve the watertight effect.

According to the present invention, the stopper portion 13
Since the guide tapered surface 11 is provided with the outer diameter gradually increasing from the seal portion 12 toward the seal portion 12,
Packing 14 compressed when screw 1 is screwed in
is suitably centered along the tapered surface 11, and the packing 14 can be compressed while being aligned along the seal portion 12, thereby preventing compression of the packing 14 in a deviated state or in a turned-up state. It never occurs.

In particular, when preventing excessive screwing by the stopper portion 13, as described above with respect to the conventional example (FIG. 6), as a problem peculiar to self-threading screws such as drill screws, the screw body 2 According to the present invention, even when the stopper portion 13 is of a small diameter near the shank portion 4 on the inner peripheral side of the seal portion 12, The amount of inclination deviation of the stopper part 13 is made relatively small compared to the axis Y, so that the uncompressed part of the seal as described above in the conventional example does not occur, and the seal 12 is compressed almost uniformly over the entire area. It becomes possible to do so.

Moreover, in the present invention, the stopper part 13 is firmly formed by the neck part 6 integrated with the metal screw main body 2, so it will not be easily damaged, and furthermore, as described above, the stopper part 13 is made of a small diameter shank part 4. Coupled with the small amount of inclination deviation, this also has the effect of preventing the stopper portion 13 from breaking and ensuring that it functions as the intended stopper.

[Brief explanation of the drawing]

Fig. 1 is a front view showing the first embodiment of the present invention, Fig. 2 is a vertical cross-sectional view of the main part, Fig. 3 is a longitudinal cross-sectional view of the same in use, and Fig. 4 is another embodiment of the stopper section. FIG. 5 is a vertical cross-sectional view showing another embodiment of the packing, and FIG. 6 is a vertical cross-sectional view showing the drawbacks of the conventional example. 1...screw, 2...screw body, 3...synthetic resin head, 4...shank part, 6...neck part, 8...
Small head, 9... Thread, 12... Seal part, 13...
...Stopper part, 14...Putskin, 20...Head with seat, 21...Neck part.

Claims (1)

[Scope of utility model registration request] In a self-threading screw formed by integrally connecting a head having a tool engaging part and a shank having a thread provided from a drill part at the tip toward the head: on the lower surface of the head. A substantially annular seal portion 12 is formed, and a substantially annular packing 14 made of an elastic material is disposed below the seal portion 12; Neck parts 6, 21 protruding from the outer periphery of the ends are integrally formed with the shank part, and a stopper part 13 is provided on the lower surface of the neck part.
and the lower surface of the stopper portion 13 is positioned between the seal portion 12 and the lower surface of the seal 14; A sealing device for a self-threading screw such as a drill screw, characterized in that it is provided with a guide tapered surface 11 whose diameter gradually increases.