JP2001020932A - Screw with falling preventing function - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a screw with a falling preventive function favourable in cost reduction and assembling by eliminating falling preventive parts and complicated work to install them. SOLUTION: This screw is constituted to prevent falling by providing a screw shaft part 131 continued to a screw head part 13, forming a non-threaded small diametrical part 15 on an intermediate part of the screw shaft part 131, constituting a screwing part 14 on the side of the screw head part 13 and a screw hooking part 16 on the head end side by separating them, providing a pair of stepped parts 15a, 15b between the screwing part 14 on the non- threaded small diametrical part 15 and the screw hooking part 16 and hooking these stepped parts 15a, 15b in a screw hole on the side of a fastening member.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a screw with a falling-off preventing function for screwing various members together.

[0002]

2. Description of the Related Art A conventional screw of this kind is generally known as shown in FIGS.

[0003] FIG. 3 shows a method in which a part 1 to be fastened is attached to a fastening part 2 by using a screw 3. It has a through hole 1a having a large diameter, and the fastening part 2 has a screw hole 2a.
have.

The screw 3 has a screw head 4 and a screw shaft 5 connected to the head 4.
Is formed with a threaded portion 5b toward the screw head 4, leaving a threadless portion 5a at the tip.
A groove 6 is formed on the outer periphery of the screw 3, and by inserting an E-ring 7 into the groove 6, a function of preventing the screw 3 from falling off is achieved.

FIG. 4 shows a screw shaft 5 shown in FIG.
The screwless portion 5a is a small-diameter screw portion 8, and a cap nut 9 is screwed onto the small-diameter screw portion 8, thereby fulfilling the function of preventing the screw 3 from falling off.

FIG. 5 shows a shaft 13 having a screw 10 connected to a head 11 and a screw 12 at the tip end.
The shaft portion 13 includes the screw portion 12 on the distal end side and the head 1
1, a screw-less stepped portion 13a is formed. The part 1 to be fastened and the part 2 to be fastened are screwed into the through hole 1a having the same inner diameter as the threaded part 12 formed in the part 1 to be fastened. After being inserted from the screw part 12 side, the screw part 12 is fastened to the fastening part 2
The screw 10 is formed by screwing the screw 10 into the screw hole 2 a, and the screw 10 is formed such that the axial length of the screwless step portion is longer than the axial length of the screw portion 12, and the screw portion 12 is fastened to the component 1. The screw 10 is inserted through the through hole 1a and is hinged and fixed to the screw hole 2a of the fastening fixture 2, thereby preventing the screw 10 from dropping off from the part 1 to be fastened.

[0007]

However, what is shown in FIGS. 3 and 4 is to prevent the screw 3 from falling off.
The use of the E-ring 7 or the cap nut 9 causes an increase in the number of parts, and also necessitates a man-hour for mounting the E-ring 7 and the cap nut 9.

In the apparatus shown in FIG. 5, since the part 1 to be fastened and the screw 10 are always in a hooked state, it is difficult to move the part 1 to be fastened while making contact with the part. When the fastener 1 is replaced, the screw 10 needs to be replaced.

In view of the above, the present invention has a drop-off function without using a drop-prevention component, and further, reduces the cost by eliminating the need for complicated processing for performing the drop-off function. It is another object of the present invention to provide a screw with a fall-prevention function having good assemblability, which eliminates the conventional work of mounting the fall-prevention parts.

[0010]

According to the present invention, there is provided a screw with a fall-preventing function, wherein a screwless small diameter portion is formed at an intermediate portion of a screw portion, and a pair of stepped portions formed by the presence of the screwless small diameter portion. However, it can be prevented from falling off by being hooked on the part to be fastened, and the drop-out prevention function by the step is realized only by machining the middle part of the screw part of the screw into a small diameter. Reduction and the need for a separate component for preventing falling off become unnecessary, and the cost can be reduced.

[0011]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The invention according to claim 1 of the present invention is characterized in that a screw head portion has a continuous screw shaft portion, and this screw shaft portion has a small diameter portion having no screw at an intermediate portion thereof. The screw threaded portion on the screw head side and the threaded threaded portion on the distal end side are separated from each other, and a pair of stepped portions is provided between the threaded threaded portion and the threaded threaded portion in the small diameter portion without screw. Features.

According to the present invention, the presence of the pair of steps makes it possible to prevent the steps from being caught by the parts to be fastened and to prevent the parts from falling off. In order to realize the above, it is possible to reduce the processing of the threaded portion and the need for a separate falling-off prevention part, thereby reducing the cost.

According to a second aspect of the present invention, a small-diameter step portion having no screw formed in an intermediate portion of the screw portion is positioned in a screw hole on the fastening member side, and the pair of step portions is caught in the screw hole. Thus, it is configured to prevent the falling off.

According to the present invention, when the screw is removed, the screw slips at a position where the screw portion and the fastening component have passed the hinged state due to the presence of the small diameter portion without the screw, and the screw is dropped. Performs the prevention function. Also, since the screw remains on the fastening component side, the contact portion of the component to be fastened to the head of the screw is machined into a U-shape, so that the component to be fastened and moved while abutting the fastening component and the fastening component. Can be easily exchanged.

FIG. 1 shows an embodiment of the present invention.
This will be described with reference to FIG.

(Embodiment 1) FIG. 1 shows the configuration of a first embodiment of the present invention. A screw 10 having a predetermined length is composed of a screw head 13 and a screw shaft 131. are doing. The screw shaft portion 131 has a screwless small-diameter portion 15 at an intermediate portion thereof, so that the screw threaded portion 14 on the screw head 13 side and the screw engaging portion 16 on the distal end side are separated, and the screw shaft portion 131 extends in the axial direction. A pair of steps 15a and 15b are formed.

The screw threading portion 14 and the screw engaging portion 16 are threaded with the same diameter, thereby simplifying the thread cutting process.

When the fastening part 1 is fastened to the part 2 to be fastened, the screw 10 is inserted into the through hole 1 a formed in the fastening part 1, and then the screw 10 of the part 2 is screwed. 2a.

As a result, the screwless small-diameter portion 1 is inserted into the screw hole 2a.
5 can be inserted to screw the screw threaded portion 14 into the screw hole 2a, and the part 1 to be fastened is clamped and fixed between the screw head 13 and the fastening part 2 (FIG. 1 ( 1)).

From this state, when the screw 10 is screwed out, as shown in FIG. 1 (2), the screwless small diameter portion 15 of the screw 10 is inserted into the screw hole 2a of the part 2 to be fastened.
Axial length a of the small diameter portion 15 without screw and the part 2 to be fastened
Since the relationship with the thickness dimension b of the screw 10 is a> b, the screw 10 only idles in the screw hole 2a. Due to the presence of the pair of steps 15a, 15b formed on the shaft 131 by the formation of the screw 15, the screwed portion 14 or the screwed portion 16 is hooked at both ends of the screw hole 2a, respectively. Unless the screw 16 is screwed out into the screw hole 2a, the screw 10 cannot be pulled out from the screw hole 2a, so that the screw 10 has a dropping function.

As a result, a mechanism for preventing the screw 10 from falling off the fastening part 1 is established. Further, the screw 10 is screwed out while being pulled toward the fastening part 1, so that the screw engaging part 16 is also screwed out from the fastening part, so that the disassembly is improved.

(Embodiment 2) FIG. 2 shows Embodiment 2 of the present invention. In Embodiment 2, similarly to Embodiment 1, the screw 10 has a screw head 13 and a screw shaft. And the screw shaft 131 is formed by forming the small diameter portion 15 having no screw in the middle portion thereof.
The screw threaded portion 14 on the screw head 13 side and the screw retaining portion 16 on the tip end formed to have the same screw outer diameter as the screw threaded portion 14 are cut off. As a result, a pair of stepped portions 15a, 15b in the axial direction is obtained. Is formed.

The case 23 constituting the fastening member 1
Has a pair of channel-shaped guide grooves 23a, 23b.
Are formed facing each other and separated from each other, and the guide grooves 23a and 23b are provided with panels 2 forming the member 2 to be fastened.
4 is fitted so as to be slidable in the front and back directions of the drawing.

Numeral 20 denotes a nut, in which a nut plate 21 is pressed into a box-shaped nut plate fixing body 22. The nut plate fixing body 22 has a through hole 22a penetrating the side wall thereof. This through hole 22
a is a screw engagement portion 14 of the screw 10 or a screw engagement portion 16
The diameter of the screw is larger than the outer diameter of the screw.

The panel 24 also has a screw 10
A through hole 24a having a diameter larger than the outer diameter of the screw of the screw engagement portion 14 or the screw retaining portion 16 is formed.

The thickness b of the nut plate 21
And the axial dimension c of the small-diameter portion 15 having no screw are formed in a dimensional relationship of c> b. From the state shown in FIG.
When the screw 10 is screwed out and the screw threaded portion 14 passes through the nut plate 21, the screw 10 has a pair of stepped portions 15 a, Due to the presence of 15b, the screwed portion 14 or the screwed portion 16 is caught in the screw hole 21a of the nut plate 21 and is prevented from falling off.

It is to be noted that the contact portion of the panel 24 with the screw head 13 is cut out in a U-shape so that the panel 24 can be moved while contacting the nut plate 21 and the panel 24 can be moved.
Can be easily replaced, and when work inside the panel 24 or attachment / detachment of the panel 24 is required, improvement in work efficiency can be expected.

[0028]

According to the screw with a drop-prevention function according to the present invention, a small diameter portion without a screw is formed in the middle portion of the screw portion.
By providing a pair of steps between the screwless small-diameter portion and the screw portion, the function of preventing the screw from falling off can be easily achieved without the need for a separate component or the like, thereby reducing cost.
Work efficiency can be improved.

[Brief description of the drawings]

FIG. 1 is a cross-sectional view of a screw with a fall prevention function according to Embodiment 1 of the present invention, where (1) shows a tightened state and (2) shows a screwed-out state.

FIG. 2 is a cross-sectional view of a screw with a fall-off prevention function according to a second embodiment of the present invention.

FIG. 3 is a cross-sectional view showing an example of a conventional screw with a fall-prevention function.

FIG. 4 is a cross-sectional view showing another example of a conventional screw with a fall prevention function.

FIG. 5 is a cross-sectional view showing still another example of a conventional screw with a fall prevention function.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Fastening member 2 Fastened member 10 Screw 13 Screw head 131 Screw shaft part 14 Screw screw part 15 Screwless small diameter part 15a, 15b Stepped part 16 Screw engaging part 20 Nut 21 Nut plate 22 Nut plate fixed body 23 Case (fastening Member) 24 plate (member to be fastened)

Claims (2)

[Claims] 1. A screw head having a screw shaft portion continuous with a screw head,
This screw shaft portion is formed by forming a screwless small-diameter portion in the middle portion, and separating the screw screw portion on the screw head side and the screw engaging portion on the distal end side. A screw with a fall-prevention function, wherein a pair of step portions are provided between the portion and the screw engaging portion. 2. A structure in which a small-diameter portion without a screw formed in an intermediate portion of a screw portion is positioned in a screw hole on a fastening member side, and a pair of stepped portions is caught in the screw hole, thereby preventing falling off. The screw with a fall-off prevention function according to claim 1, wherein: