JPH08235682A - Cam-operated switch for vcr - Google Patents

Abstract

PROBLEM TO BE SOLVED: To prevent the malfunction of a VCR by generating signals accurately indicating the operation mode of the VCR by integrally forming a stator cam switch and cam gear so as to eliminate unmatching between the cam switch and cam gear at the time of assembly. SOLUTION: A stator cam switch 20 and cam gear 10 are coupled with each other when a cylindrical drum 21 is put in a socket 11a formed of a protruded ring 11. The bottom face of the drum 21 is sufficiently brought nearer to the top face 10b of the gear 10 in the ring 11 so that a conductive brush 12 can effectively come into contact with a circuit pattern formed on the bottom face of the drum 21. Therefore, the cam switch 20 can generate signals supplied to a microprocessor incorporated in a VCR in accordance with the contacting state of the brush 12 with the circuit pattern on the bottom face of the drum 21.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a cam switch used in a video cassette recorder (VCR), and more particularly, it accurately detects the operating mode of the VCR at that time,
The present invention relates to a cam switch capable of supplying detected information to a microprocessor incorporated in a VCR.

[0002]

2. Description of the Related Art As is well known, a cam switch of a VCR has a pair of slant poles (slants) provided therein.
of the video cassette, and by detecting whether the video cassette is inserted or not.
It is used to determine the operating mode of R.

The position of the tilt pole changes depending on the operation mode of the VCR, that is, reproduction, fast-forward, pause or the like. This allows the VCR operating mode to be determined by detecting the position of the tilt pole and by detecting whether the video cassette is inserted into the VCR.

FIG. 1 shows a conventional cam switch including a cam gear 1 having three bosses 1a, a rotor cam switch 2 having a conductive brush 2a, and a stator cam switch 3. It is shown.
A central shaft hole 5 is provided in each of the cam gear 1, the rotor cam switch 2, and the stator cam switch 3.

The three bosses 1a are the upper surface 1b of the cam gear 1.
Is provided so as to surround the central shaft hole 5. On the bottom surface (not shown) of the rotor cam switch 2, there are three bosses 1
A pair of downwardly projecting guide portions (not shown) are provided so as to interact with a. On the other hand, the conductive brush 2a attached to the upper surface of the rotor cam switch 2 has a plurality of conductive teeth, and a circuit pattern (not shown) provided on the bottom surface of the stator cam switch 3 through the conductive teeth. ) Is in electrical contact with. All the conductive teeth of the conductive brush 2a are electrically connected. Therefore, from the portion of the circuit pattern provided on the bottom surface of the stator cam switch 3 that is in contact with one of the conductive teeth of the conductive brush 2a, through the conductive brush 2a, the other conductive of the conductive brush 2a. Current can flow to other portions of the circuit pattern that are in contact with the sex teeth.

When the guide portion provided on the bottom surface of the rotor cam switch 2 interacts with the three bosses 1a on the upper surface 1b of the cam gear 1, the rotor cam switch 2 rotates in conjunction with the cam gear 1. Rotor cam switch 2
When is rotated, the contact state between the circuit pattern provided on the bottom surface of the stator cam switch 3 and the conductive brush 2a changes, and a signal corresponding to the circuit pattern in contact with the conductive tooth is generated at each moment. It By supplying the signal thus generated to the microprocessor, the microprocessor is informed of the exact rotational state of the cam gear 1 (that is, how much the cam gear 1 is rotated from the reference position).

The rotation state of the cam gear 1 changes depending on whether or not the video cassette is inserted in the VCR. It also changes depending on the positions of the pair of tilting poles provided in the VCR. A cassette tray (not shown) and a tilting pole that support the video cassette when it is inserted in the VCR are attached to the cam gear 1 by a lever arm, for example using the lever principle. Mechanically linked. In this way, when the positions of the cassette tray and the inclined pole shift, the cam gear 1 rotates. Since the positions of the two inclined poles change depending on the operation mode of the VCR (for example, reproduction, insertion, rewinding, take-out, etc.), the rotation state of the cam gear 1 is eventually changed to the operation mode of the VCR at that time. Dependent. Therefore, the signal generated from the stator cam switch 3 is V
It changes according to the operating mode of CR.

In such a conventional cam switch,
The conductive teeth of the conductive brush 2a and the stator cam switch 3
The contact with the circuit pattern provided on the bottom surface of the device must be precise so that an accurate signal is generated and transmitted to the microprocessor. However, since the tolerance of the circuit pattern provided on the bottom surface of the stator cam switch 3 is small, high accuracy is required for assembling the above-mentioned conventional cam switch. Therefore, the conventional cam switch has a drawback that misalignment between the cam gear 1 and the rotor cam switch 2, for example, is likely to occur, and an erroneous inaccurate signal may be generated to cause malfunction of the VCR.

[0009]

SUMMARY OF THE INVENTION Accordingly, it is an object of the present invention to accurately detect the operating mode of a VCR at any given time and to provide the detected information to a microprocessor incorporated within the VCR. It is to provide a cam switch.

Another object of the present invention is to provide an improved cam gear which also serves as a conventional rotor cam switch and does not require a separate rotor cam switch.

[0011]

In order to achieve the above object, according to the present invention, a video cassette recorder (VC) is provided.
A cam switch used for R), wherein a cam gear having a coaxial protruding ring forming a socket is provided on an upper surface, and a conductive property provided on the upper surface of the cam gear in an area surrounded by the protruding ring. There is provided a VCR cam switch including a brush, a stator cam switch having a cylindrical protruding drum provided on a bottom surface thereof, and a circuit pattern provided on a bottom surface of the cylindrical protruding drum.

[0012]

BEST MODE FOR CARRYING OUT THE INVENTION Preferred embodiments of the present invention will now be described in more detail with reference to the drawings.

FIG. 2 shows the cam switch of the present invention used in a VCR. This cam switch includes a cam gear 1 to which a conductive brush 12 (see FIG. 3) is attached.
0 and a stator cam switch 20.

On the upper surface of the cam gear 10, a socket 11a is provided.
A protruding ring 11 is provided which forms The protruding ring 11 is coaxial with the cam gear 10, and its diameter is smaller than that of the cam gear 10. Protruding ring 1
1, the upper surface of the cam gear 10 is the upper surface 1 outside the ring.
0a and the upper surface 10b in the ring.

As shown in FIG. 3, the cam gear 10 has a conductive brush 12 provided on the upper surface 10b in the ring. The conductive brush 12 is provided with a plurality of conductive teeth.

On the bottom surface of the stator cam switch 20, there is provided a cylindrical projecting drum 21 (hereinafter referred to as a cylindrical drum) which is fitted with a socket 11a formed by the projecting ring 11. Further, a circuit pattern (not shown) is provided on the bottom surface of the cylindrical drum 21.

Stator cam switch 20 and cam gear 10
Are coupled by fitting the cylindrical drum 21 into the socket 11a formed by the protruding ring 11. The cylindrical drum 21 is fitted into the socket 11 a so that the cam gear 10 can rotate with respect to the stator cam switch 20. Further, the bottom surface of the cylindrical drum 21 and the top surface 10b in the ring are sufficiently close to each other so that the conductive brush 12 can effectively contact the circuit pattern provided on the bottom surface of the cylindrical drum 21. . In this way, the stator cam switch 20 is supplied to the microprocessor (not shown) incorporated in the VCR in accordance with the contact state between the circuit pattern on the bottom surface of the cylindrical drum 21 and the conductive brush 12. Signal can be generated.

In the above-described VCR cam switch according to the present invention, the rotational state of the cam gear 10 (that is, how much the cam gear 10 is rotated from the reference position) depends on the operating mode of the VCR (that is, reproduction). , Eject, insert, rewind, fast forward, etc.). The cam gear 10 is coupled to a pair of tilting poles (not shown) and a video cassette holder (not shown) incorporated in the VCR. When the positions of these elements are changed by a command from the microprocessor according to a predetermined operation mode of the VCR, the cam gear 10 rotates and interacts with a circuit pattern provided on the bottom surface of the cylindrical drum 21. The position of the conductive brush 12 that acts changes. As a result, the signal provided by the stator cam switch 20 to the microprocessor changes.

While particular embodiments of the present invention have been described above, it will be apparent to those skilled in the art that various modifications can be made without departing from the scope of the claims set forth herein.

[0020]

Therefore, according to the present invention, since the conventional rotor cam switch and cam gear are integrally formed, the misalignment at the time of assembly is eliminated, and the accurate VCR operating mode is accurately displayed. A signal can be generated.

[Brief description of drawings]

FIG. 1 is an exploded perspective view of a conventional VCR cam switch.

FIG. 2 is an exploded perspective view of a VCR cam switch according to the present invention.

FIG. 3 is a plan view of a cam gear used in the cam switch of the present invention.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 cam gear 1a boss 1b upper surface 2 rotor cam switch 2a conductive brush 3 stator cam switch 5 center shaft hole 10 cam gear 10a upper surface outside the protruding ring 11 of the cam gear 10b upper surface inside the protruding ring 11 of the cam gear 10 11 protruding ring 11a socket 12 Conductive brush 20 Stator cam switch 21 Cylindrical drum

Claims (2)

[Claims] 1. A cam switch used for a video cassette recorder (VCR), comprising: a cam gear having a coaxial protruding ring forming a socket provided on an upper surface; and a cam ring surrounded by the protruding ring on the upper surface of the cam gear. A conductive brush provided in the area, a stator cam switch having a cylindrical protruding drum provided on the bottom surface thereof, and a circuit pattern provided on the bottom surface of the cylindrical protruding drum. Cam switch for VCR. 2. A video cassette recorder comprising the cam switch according to claim 1.