JPH082362Y2 - Detector locking mechanism - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial field of application] The present invention relates to a lock mechanism for preventing tampering of a passive infrared detector which is attached to a ceiling or a wall and used as a detector for a crime prevention system.

[Conventional technology]

In general, a detector mounted on a ceiling or a wall surface is composed of a base portion having terminals for wiring power supply lines and signal lines, and a detector main body held by the base portion. At the time of installation work, first fix the base part to the ceiling, etc., then turn the detector body around the base part as shown in Fig. 5, and set the groove as the engagement receiver of the detector body and the engagement claw of the base part. Engage with each other to hold the detector body on the base portion. Before holding the detector body on the base part, the terminals provided on the base part are wired with the electric wires drawn from the power supply part and the signal receiving part installed at another place. The detector body is equipped with contact fittings corresponding to the terminals of the base part,
The structure is such that electrical continuity is obtained between the terminals and the contact fittings at the same time when the detector main body is rotated with respect to the base portion. Such a structure is often used because the installation work is simple.

In the case of a crime prevention detector, the detector body can be easily removed from the base after the installation work described above to prevent internal damage, wiring work, and changes in sensitivity settings, etc. You need to be unable to. Therefore, a lock mechanism using a lock screw that cannot be rotated without using a tool has been adopted. This locking mechanism is shown in FIG. This is a lock screw 4 provided with the base portion 1 and the detector body 2 on the detector body side.
It is fixed by utilizing the axial movement of the. A nut 9 is embedded in the detector body 2, and when the lock screw 4 is tightened, the lock screw 4 enters the base portion 1 side,
A portion that comes into contact with the protruding portion 8 provided on the base portion 1 side is generated. In this state, the rotation of the lock screw 4 in the direction perpendicular to the axial direction (the direction in which the detector body 2 is removed from the base portion 1) is blocked. As described above, the structure is such that the detector body cannot be detached from the base portion unless a tool such as a screwdriver is used at a minimum, thereby preventing mischief.

[Problems to be solved by the invention]

With the conventional lock mechanism of the detector, the lock screw provided on the detector main body prevents mutual rotation between the base and the detector main body when it directly hits the protrusion of the base, so the lock mechanism is sufficient. In order to operate the lock screw, it was necessary to rotate the lock screw many times, and to sufficiently secure the contact portion between the shaft portion of the lock screw and the projection on the base side. In particular, when the detector main body case and the base portion are formed of a resin molded component, this contact portion needs to be large, and the labor required to make the operation of the lock mechanism sufficient is large. In addition, since the nut is provided inside the detector body, it is necessary to use a long lock screw. Therefore, there is a problem that the space occupied by the lock mechanism becomes large, and as a result, the entire detector becomes large.

Furthermore, the complete operating condition of the lock mechanism can be recognized when the screw head hits the outer wall surface of the detector body and stops, but when releasing the lock mechanism, the lock screw is prevented from rotating no matter how loose the lock screw is. There is also the inconvenience of not being able to recognize when the lock mechanism has been released.

[Means for solving problems]

The lock mechanism of the detector of the present invention uses a lock fitting that rotates and rotates with the rotation of the lock screw, and the lock fitting restricts the rotation in the direction to remove the detection body from the base part. The lock mechanism is operated and released by rotating the lock screw.

[Action]

According to this configuration, even if the outer shape of the detector is small, the lock mechanism can be housed therein. In addition, the lock screw is shortened and the push nut for retaining is fixed to the bottom of the lock screw, so it can be stopped not only when the lock mechanism operates but also when releasing it by rotating the lock screw about two times. The property is also improved.

〔Example〕

FIG. 1 is a cross-sectional view of the lock mechanism of the present invention, and FIG. 2 is the back side of the base portion (the ceiling side when attached to the ceiling).
It is the figure seen from. FIG. 3 is a perspective view of a detector having a lock mechanism according to the present invention. FIG. 1 is an enlarged sectional view taken along line XX ′ in FIG.

The disk-shaped base portion 1 is provided with a lock screw 4 penetrating the outer wall, and the lock metal fitting 3 that rotates and rotates with the rotation of the lock screw 4 stops the detector body 2 and the base portion 1 from rotating relative to each other. . Lock screw 4 is base 1
Through the outer wall of the lock fitting 3 and is joined to the screw hole of the lock fitting 3, and a push-out prevention nut 7 is fixed to the bottom portion (upper end portion of the screw shaft portion in FIG. 1) of the lock screw 4. A compression spring 5 and a polyethylene washer 6 are provided between the lock fitting 3 and the inner surface of the outer wall of the base portion 1.

The screw thread portion of the lock fitting 3 is pressed by the compression spring 5 with a force acting in the bottom direction (upward direction in FIG. 1) of the lock screw 4. In the opposite direction, the polyethylene washer 6 is pressed against the inner surface of the outer wall of the base portion 1 by its reaction, and the head of the lock screw 4 is in contact with the outer wall surface of the base portion 1. The portions where friction occurs when trying to rotate the lock screw 4 are between the lock screw 4 and the thread of the lock fitting 3, between the lock fitting 3 and the compression spring 5, between the compression spring 5 and the polyethylene washer 6, and between the polyethylene and the polyethylene washer. Between the washer 6 and the inner surface of the outer wall of the base portion 1,
It is between the outer wall surface of the base 1 and the lock screw head.
If the frictional force acting between the lock fitting 3 and the inner surface of the outer wall of the base portion 1 is larger than the frictional force acting between the lock screw 4 and the thread of the lock fitting 3, the lock screw 4 is locked when rotated. The metal fitting 3 does not move relative to the inner surface of the outer wall of the base portion 1, and the lock metal fitting 3 moves toward the screw head as the lock screw 4 rotates. Since the polyethylene washer 6 for reducing the frictional force therebetween is provided between the base 1 and the inner surface of the outer wall, when the lock screw 4 rotates, the lock fitting 3 also immediately starts to rotate.
This polyethylene washer 6 has a friction coefficient enough to reduce the frictional force acting between the lock fitting 3 and the inner surface of the outer wall of the base portion 1 than the frictional force between the lock screw 4 and the thread of the lock fitting 3. However, a washer made of another material may be any as long as it has a friction coefficient equivalent to this.

Next, a method of operating and releasing the lock mechanism of the present invention will be described according to an operating procedure. The detector main body 2 is turned around with respect to the base portion 1 fixed to the ceiling, and the engaging claws of the base portion 1 are engaged with the grooves as the engagement receivers of the detector main body 2 to attach the detector main body 2 to the base portion 1. To hold. And
Turn the lock screw 4 provided on the base portion 1 in the tightening direction. At this time, according to the principle described above, the lock fitting 3 starts to rotate from the position a in FIG. 2 and comes into contact with the stopper B to stop at the position b. During this rotational movement, the lock fitting 3 is in a state of being floated from the inner surface of the outer wall of the base portion 1 toward the lock screw bottom portion (the retaining push nut 7 side) by the compression spring 5. For this reason, the cutout portion C on the bottom surface side (the lower side in FIG. 1) of the fan-shaped portion of the lock fitting 3 and the detector body side.
The distance between the concave portion and the bottom surface of the concave portion may be small. When the lock screw 4 is further tightened from here, the fan-shaped portion of the lock fitting 3 moves and stops until it comes into contact with the bottom surface of the recess of the notch C on the detector body side. FIG. 1 is a sectional view of this state. The rotation of the lock screw 4 required up to this point is about two rotations. In this state, the bottom surface side of the fan-shaped portion of the lock fitting 3 is fitted in the recess of the cutout portion C of the main body. Therefore, the direction of removing the detector body 2 (arrow D in FIG. 2)
Rotation) is blocked because the cut wall surface located at the upper end of the notch C shown in FIG. 2 is in contact with the lock fitting. Further, the locking effect occurs even when the lock metal fitting 3 has not moved to the position of the stopper B and has not ended yet, the lock metal fitting 3 rotates a little and a little approaches the cut wall surface of the notch C.

When releasing the lock, rotate the lock screw 4 in the opposite direction to the above.
Loosen. Initially, the lock fitting 3 is the lock screw 4
The frictional force of the screw portion generated when trying to rotate together with the fastening force acting between the bottom surface side of the fan-shaped portion of the lock fitting 3 and the bottom surface of the recessed portion of the cutout portion C (the portion that contacts when the fitting is tightened) Since it is smaller than the frictional force of the lock fitting 3, the lock screw 4 rotates along the thread of the lock fitting 3, and the lock fitting 3 moves to the second position.
It moves axially (upward in FIG. 1) at the position shown in FIG. When the lock screw 4 is loosened, the tightening force between the bottom surface side of the fan-shaped portion of the lock fitting 3 and the bottom surface of the recessed portion of the notch C (the portion that is in contact when the fitting is tightened) decreases, and the magnitude relationship of the frictional force is reduced. Reverse, and the lock fitting 3 tries to rotate together with the lock screw 4. However, the frictional force generated when the lock screw 4 is rotating along the thread of the lock fitting 3 causes the friction between the lock fitting 3 and the inner surface of the outer wall of the base 1 (the lock fitting 3, the compression spring 5, the polyethylene washer). 6, base part 1
The lock screw 4 continues to rotate along the thread of the lock fitting 3 as long as it is smaller than the frictional force due to the repulsive force of the compression spring 5 generated at all the contact portions on the outer wall and inner surface of the lock metal fitting 3. In the present invention, since the polyethylene washer 6 is inserted between the compression spring 5 and the inner surface of the outer wall of the base portion 1, the lock metal fitting 3 can rotate together with the lock screw 4 quickly and smoothly. Lock metal fitting 3 that started to rotate together with lock screw 4
Is rotationally moved to the position a and the lock is released. Further, when the lock screw 4 is loosened, the lock fitting 3 moves upward to the position of the retaining push nut 7 provided at the bottom of the lock screw 4 at the position a and stops. The operator recognizes the end of the lock release when the rotation is stopped.

[Effect of device]

According to the present invention, the lock fitting moves in conjunction with the rotation of the lock screw, and the lock fitting prevents the rotation of the main body and the base part. There are fewer restrictions when this mechanism is installed, and the degree of freedom in designing the entire detector is greatly expanded. In addition, by only slightly rotating the lock screw (about 2 turns), the operation and release of the lock mechanism is completed,
In both rotations, the rotation stopped last, so the end of the operation was recognized at that position, and the workability was also improved.

[Brief description of drawings]

FIG. 1 is a sectional view of a lock mechanism of the present invention. FIG. 2 is a view of the lock mechanism of the present invention seen from the back surface of the base portion. FIG. 3 is a perspective view of a detector having a lock mechanism according to the present invention. FIG. 4 is a sectional view of a conventional lock mechanism.
FIG. 5 is a perspective view of a conventional detector having a lock mechanism.

Claims (1)

[Scope of utility model registration request] 1. A detector main body is rotated by rotating a detector main body with respect to a base portion fixed to a ceiling surface or the like, and a groove serving as an engagement receiver of the detector main body is engaged with an engaging claw of the base portion. In the detector of the structure to be held in the base portion, a lock screw is passed through the outer wall of the base portion, and a retaining push nut is fixed to the bottom portion of the lock screw, between the retaining push nut and the inner wall of the base portion, A plate-shaped lock fitting provided with a screw hole corresponding to the lock screw and a compression spring are arranged, and a resin washer is provided between the compression spring and the inner wall of the outer wall of the base to reduce the frictional force therebetween.
The frictional force acting between the resin washer and the compression spring, or between the resin washer and the inner wall of the outer wall of the base part, is better than the frictional force generated by the repulsive force of the compression spring between the lock screw and the thread of the lock fitting. The lock metal fitting is made smaller so that the lock metal fittings can easily rotate together with the rotation of the lock screw, and the lock metal fittings that rotate together by tightening the lock screw project toward the detector main body held by the base part. The lock mechanism of the detector is characterized in that the movement in the turning direction is restricted when the is removed from the base part.