JP2000320522A - Countersunk bolt with detent part - Google Patents

Abstract

PROBLEM TO BE SOLVED: To have a fastening load resistance property by providing a protrusion part between a flat pan shaped head part for receiving tightly fastening and a screw rod part, and disposing an expansion part, which is overlapped with the screw rod part on a center part of an upper surface of a head and overlapped with all or a part of the protrusion part. SOLUTION: A bolt A is formed, by interposing a detent part 3 between a screw rod part 1 and a head part 2 for receiving tightly fastening. The detent part 3 is formed as a protrusion part 3, whose four square corner parts of cross section are protruded outside the radial direction of the screw rod part 1 to restrict rotation together with a nut, when fastening operation is carried out by the nut. The head part 2 is formed to receive tight fastening, when the fastening operation is carried out, formed in a flat conical shape, and is provided with an expansion part 5, whose upper surface overlapped with the screw rod part 1, is formed a flat shape at the center part of the upper surface 2' of the head part 2. An outer peripheral part 5' of the expansion part 5 is arranged at a position enclosed the detent part 3 via the head part 2 in plane view, and a diameter of the expansion part 5 is enlarged comparing with that of the detent part 3, so as to overlap the expansion part 5 with the detent part 3. The head part 2 is stored by engaging with the inside of a recessed-in part formed on a washer, and the fastening work carried out with only a screw operation of the nut.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION The present invention relates to a non-circular section having a projection between a flat plate-like head for tightening and receiving and a threaded part, which partly or entirely projects radially outward from the threaded part. The present invention relates to a countersunk bolt with a detent provided with a detent.

[0002]

2. Description of the Related Art A countersunk bolt provided with a detent portion engages a dish-shaped head with a recess provided on an article, and engages the detent with a locking portion (hole) provided in the recess. When the articles are fastened to each other with the nut screwed into the threaded rod part, the fastening operation with the nut is performed smoothly without rotating together with the nut due to the engagement relationship between the locking part and the detent part. However, the head for tightening is made of a flat body,
The head may be broken at the time of fastening because the movement in the rotation direction is restricted by the engagement relationship at the time of fastening and the fastening load is concentrated in the axial direction.

The present invention has been made in view of the above-described circumstances, and has been devised to provide a countersunk bolt with a non-rotating portion having a tightening load resistance.

[0004]

SUMMARY OF THE INVENTION A non-circular detent having a protrusion between a flat plate-like head for tightening and receiving and a screw portion, the portion of which partially or entirely projects radially outward from the screw portion. In the bolt provided with a portion, a bulging portion is provided at the center of the upper surface of the head, the bulging portion overlapping the screw rod portion and overlapping all or a part of the protruding portion.

[0005]

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a front view, FIG. 2 is a plan view, FIG. 3 is a bottom view, and FIG. FIG. 5 is a partially enlarged front view showing a state of use, and FIG.

In the drawing, A is a bolt, and the bolt A is constituted by interposing a detent member 3 between a threaded rod portion 1 provided with a screw on the tip end side and a tightening receiving head 2.

[0007] The detent part 3 constituting the bolt A is
It has a rectangular cross section, and the four corners of the square are
3 ', 3', 3 ', 3' projecting radially outward of
The nut 4 at the time of tightening operation with the nut 4 is provided.
Regulate co-rotation with.

The head 2 serves as a tightening support during the tightening operation, and has a flat and slightly frustoconical shape.
At the center of the upper surface 2 ', there is provided a bulging portion 5 having a flat upper surface (which can be formed of a minimum necessary material by flattening), which overlaps with the threaded rod portion 1, and an outer peripheral end 5' of the bulging portion 5 The detent portion 3 is disposed at a position surrounding the head portion 2 in a plan view, and is rotated so as to overlap with the detent portion 3 including the protruding portions 3 ', 3', 3 ', 3'. The diameter b is larger than the diameter a of the stopper 3.

The bulging portion 5 may overlap the threaded rod portion 1 and partially overlap with the projecting portions 3 ', 3', 3 ', 3'. May be determined in consideration of the degree of tensile force acting on the lower surface of the head 2 (boundary portion with the outer peripheral end of the rotation preventing portion 3) at the time of fastening with the nut 4, but as in the embodiment, 3
', 3', 3 ', and 3' are desirably overlapped with all (the whole area).

The head 2 has a flat truncated conical shape so that it can be immersed in a recess 7 formed in the washer 6 as shown in FIG. Does not occur.

[0012] For example, as shown in FIG. 6, a joining member 12 (jointly known without giving specific examples) for joining a wooden vertical member (post) 10 and a wooden horizontal member (horizontal member) 11 is provided. The bolt A is used in combination, and the horizontal member 1 is attached to the other side of the joint fitting 12 having one side assembled to the vertical member 10.
The nut 4 is used by screwing the nut 4 to the tip of the screw 1 protruding from the joint fitting 12.

The washer 6 is provided with a locking hole 13 communicating with the recess 7, and the locking hole 13 matches the outer shape of the rotation preventing portion 3 to prevent the bolt A from rotating together with the nut 4. .

The detent portion 3 has a rectangular shape in the embodiment, but it is sufficient that a part or all of the detent portion 3 has a non-circular cross section projecting radially outward.

[0014]

The present invention has the configuration described above,
As with the conventional detent bolt, the head is engaged in a recess formed in a washer or other article and is housed, so that the tightening operation can be performed only by screwing the nut, of course, when tightening the nut, Even if a pulling force acts on the lower surface portion of the head that is the boundary portion with the rotation preventing portion, since the lower surface portion of the head completely or partially overlaps with the bulging portion,
Since the lower surface portion of the head is reinforced, it is possible to provide a countersunk bolt with a detent portion that does not break (break) from the portion due to the flatness of the head.

[Brief description of the drawings]

FIG. 1 is a front view.

FIG. 2 is a plan view.

FIG. 3 is a bottom view.

FIG. 4 is a sectional view taken along line xx of FIG. 1;

FIG. 5 is a partially enlarged front view.

FIG. 6 is a partially cutaway front view showing a use state.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Screw part 2 Dish-shaped head 3 Detent part 3 'Projecting part 5 Swelling part

Claims (1)

[Claims] 1. A non-circular detent having a non-circular cross-section between a flat dish-shaped head for tightening and receiving and a screw rod, the protrusion having a part projecting radially outward from the screw rod. In the bolt, the screw portion overlaps the center portion of the upper surface of the head,
In addition, a countersunk bolt with a detent portion provided with a bulging portion overlapping all or a part of the protruding portion.