CN1136702A - Cam switch for cassette magnetic tape vedeo recorder - Google Patents
Cam switch for cassette magnetic tape vedeo recorder Download PDFInfo
- Publication number
- CN1136702A CN1136702A CN95117559A CN95117559A CN1136702A CN 1136702 A CN1136702 A CN 1136702A CN 95117559 A CN95117559 A CN 95117559A CN 95117559 A CN95117559 A CN 95117559A CN 1136702 A CN1136702 A CN 1136702A
- Authority
- CN
- China
- Prior art keywords
- cam
- cam switch
- video cassette
- cassette recorder
- cam gear
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Pending
Links
- 230000001419 dependent effect Effects 0.000 description 2
- 230000004048 modification Effects 0.000 description 1
- 238000012986 modification Methods 0.000 description 1
Images
Classifications
-
- G—PHYSICS
- G11—INFORMATION STORAGE
- G11B—INFORMATION STORAGE BASED ON RELATIVE MOVEMENT BETWEEN RECORD CARRIER AND TRANSDUCER
- G11B15/00—Driving, starting or stopping record carriers of filamentary or web form; Driving both such record carriers and heads; Guiding such record carriers or containers therefor; Control thereof; Control of operating function
- G11B15/02—Control of operating function, e.g. switching from recording to reproducing
- G11B15/10—Manually-operated control; Solenoid-operated control
- G11B15/103—Manually-operated control; Solenoid-operated control electrically operated
-
- G—PHYSICS
- G11—INFORMATION STORAGE
- G11B—INFORMATION STORAGE BASED ON RELATIVE MOVEMENT BETWEEN RECORD CARRIER AND TRANSDUCER
- G11B15/00—Driving, starting or stopping record carriers of filamentary or web form; Driving both such record carriers and heads; Guiding such record carriers or containers therefor; Control thereof; Control of operating function
- G11B15/18—Driving; Starting; Stopping; Arrangements for control or regulation thereof
- G11B15/26—Driving record carriers by members acting directly or indirectly thereon
Landscapes
- Rotary Switch, Piano Key Switch, And Lever Switch (AREA)
Abstract
A cam switch which can be used in a video cassette recorder contains a cam gear, a cam switch stator, a circuit wafer and a conduction brush. The top surface of the cam gear is arranged with a protruding cirque to form a hollow cylinder shaped socket. A protruding cylinder shaped drum is arranged on the underside of the cam switch stator. The circuit wafer is formed on the underside of the protruding cylinder shaped drum. The conduction brush is arranged on the top surface of the cam gear, and inside the protruding cirque. The cam switch does not need a single cam switch rotor, thus preventing the error signal from appearing, thereby enabling the accurate reflection of the video cassette recorder signal under the special time operation mode.
Description
The present invention relates to a cam switch for a video cassette recorder, and more particularly, to a cam switch capable of accurately detecting an operation mode of a video cassette recorder at a specific timing and supplying the information to a microprocessor installed in the video cassette recorder.
As is known, a cam switch in a video cassette recorder determines the mode of operation of the video cassette recorder at a particular moment by detecting the position of a pair of diagonal rods provided therein and by detecting whether a video cassette is loaded therein.
The position of the diagonal rods depends on the mode of operation of the video cassette recorder at that moment, i.e. play, fast forward, pause, etc. Thus, the cam switch can determine the operation mode of the video cassette recorder at any time by detecting the position of the tilt lever and by detecting whether the video cassette is loaded in the video cassette recorder.
Fig. 1 shows a conventional cam switch comprising a cam gear 1 provided with three cam pins 1a, a cam switch rotor 2 with conductive brushes 2a and a cam switch stator 3. Further, the cam gear 1, the cam switch rotor 2, and the cam switch stator 3 all have a central shaft hole 5.
Three male pins 1a are mounted around the central axis 5 and on the top surface 1b of the male gear wheel 1. The bottom surface (not shown) of the cam rotor 2 has a set of protruding guides (not shown) that contact the three pins 1 a. And the conductive brush 2a mounted on the top surface of the cam rotor 2 has a plurality of conductive teeth (not shown) and makes electrical contact with a circuit board (not shown) provided on the bottom surface of the cam switch stator 3 through the conductive teeth. The conductive teeth of the conductive brush 2a are electrically connected. Thus, current can flow from one portion of the circuit board on the bottom surface of the cam-switch stator 3, which is being electrically connected to one conductive tooth of the conductive brush 2a, through the conductive brush 2a to another portion of the circuit board being contacted by the other conductive tooth of the conductive brush 2 a.
The boss guide on the bottom surface of the cam switch rotor 2 interacts with the three boss pins 1a on the top surface 1b of the cam tooth 1 to rotate the cam switch rotor 2 together with the cam gear 1. The rotation of the cam switch rotor 2 in turn changes the contact pattern of the conductive brushes 2a with the circuit board on the bottom surface of the cam switch stator, generating a signal based on the conductive teeth being in contact with parts of the circuit board at this moment, the signal thus generated being sent to the micro information processor again, thus providing information about the exact orientation of the cam gear 1, i.e. how much it has been rotated relative to the reference position.
The orientation of the cam gear 1 varies depending on whether or not a video cassette is loaded in the video cassette recorder and the position of a pair of tilt levers provided in the video cassette recorder. The tilt lever and the video cassette are located in the video cassette recorder, and the cassette holder holding the video cassette is mechanically connected to the cam gear by, for example, a lever arm. The cam gear 1a has to rotate together with the derailleur in the position of the cassette type rack and the tilting lever. Since the position of the tilt lever depends on the mode of operation of the video cassette recorder at the time, i.e. play, load, rewind, eject, etc., the orientation of the cam gear 1 is decisively dependent on the mode of operation of the video cassette recorder at the time. Thus, the signal generated by the cam switch stator is dependent upon the mode of operation of the video cassette recorder.
However, in such a conventional cam switch, the contact of the conductive teeth of the conductive brush 2a with the circuit board on the bottom surface of the cam switch stator 3 must be accurate in order to generate a correct signal and send it to the micro information processor. However, the above-mentioned prior art cam switch requires a high degree of accuracy in the operation of the components therein due to the low tolerance of the circuit board inserted on the bottom surface of the cam switch stator. For example, if the cam gear 1 and the cam switch stator 2 are even slightly misaligned, the conventional cam switch is liable to generate an erroneous signal, resulting in erroneous operation of the video cassette recorder.
It is therefore a primary object of the present invention to provide an improved cam switch which provides accurate information to a microprocessor installed in a video cassette recorder about the mode of operation of the video cassette recorder at a particular time.
It is a further object of the present invention to propose an improved cam gear for a cam switch which can incorporate the action of a cam switch rotor so as to obviate the necessity of providing a separate cam switch rotor.
According to the present invention, there is provided a cam switch for a video cassette recorder, comprising: a cam gear having a protruding ring, a hollow cylindrical socket being formed on a top surface of the cam gear; a cam switch stator having a protruding cylindrical drum on a bottom surface thereof; a circuit board formed on the bottom surface of the protruding cylindrical drum; and a conductive brush mounted on the top surface of the cam gear and protruding into the annular ring.
The above and other objects and features of the present invention will become apparent from the following description of the preferred embodiments, which is to be read in connection with the accompanying drawings. Wherein,
fig. 1 is an exploded perspective view showing a cam switch used in a conventional video cassette recorder;
fig. 2 is an exploded perspective view showing a cam switch for use in a video cassette recorder according to the present invention;
fig. 3 is a plan view of a cam gear used in the cam switch of the present invention.
Referring to fig. 2, the cam switch of the present invention is shown for use in a video cassette recorder. The cam switch includes a cam gear 10 equipped with a conductive brush 12 and a cam switch stator 20.
The cam gear 10 has a ring 11 protruding on its top surface to form a socket 11 a. The projecting ring 11 is coaxial with the cam gear 10 and has a smaller diameter than the cam gear 10. Further, the protruding ring 11 divides the top surface of the cam gear 10 into an unenclosed top surface 10a and an enclosed top surface 10 b.
As shown in fig. 3, the cam gear 10 has a conductive brush 12 mounted on the enclosed top surface 10 b. The conductive brush 12 has a plurality of conductive teeth.
The cam switch stator 20 has on its bottom surface a projecting cylindrical drum 21 which cooperates with a socket 11a constituted by the projecting ring 11. The cylindrical drum 21 is provided with a circuit board (not shown) on the bottom surface thereof.
The cam switch stator 20 and the cam gear 10 can be combined by the cylindrical drum 21 being fitted into the socket 11a constituted by the projecting ring 11. The cylindrical drum 21 is inserted into the socket 11a to allow the cam gear 10 to rotate relative to the cam switch stator 20. Further, the bottom surface of the cylindrical drum 21 and the enclosed top surface of the cam gear 10 are close enough to enable the conductive brush 12 to effectively contact the circuit board on the bottom surface of the cylindrical drum 21. In this manner, the cam switch stator 20 can generate and supply a signal to a microprocessor (not shown) installed in the video cassette recorder according to how the circuit board on the bottom surface of the cylindrical drum 21 is in contact with the conductive brush.
In the above-described cam switch of the present invention for use in a video cassette recorder, the orientation of the cam gear 10, i.e., how much it has been rotated from the reference position, depends on the operation mode of the video cassette recorder at the moment, i.e., play, eject, load, rewind, fast-forward, etc. The cam gear 10 is connected to a pair of tilt levers (not shown) and a cassette holder (not shown) installed in the video cassette recorder. When the positions of these components are changed by an instruction from the microprocessor according to the required operation mode of the video cassette recorder, the cam gear 10 is rotated, thereby changing the mode of action of the conductive brush 12 with the circuit board on the bottom surface of the cylindrical drum 21. This in turn changes the signal provided by the cam switch stator 20 to the microprocessor.
The cam switch of the present invention for use in a video cassette recorder as described above eliminates a possible source of error caused by combining the cam switch rotor and the cam gear 10 into the cam gear 10. As a result, the cam switch of the present invention avoids the generation of false signals that may occur due to errors in bringing the cam gear and the cam switch rotor together. In this way, the conductive brush 12 can always be brought into contact with and fitted to the circuit board provided on the bottom surface of the cylindrical drum correctly, so that generation of an accurate signal is possible.
While the invention has been shown and described with reference to certain embodiments, it will be apparent to those skilled in the art that changes and modifications may be made without departing from the spirit and scope of the invention as defined in the following claims.
Claims (2)
1. A cam switch for use in a video cassette recorder, comprising:
a cam gear having on a top surface thereof a ring coaxially disposed therewith forming a projection of the socket;
a conductive brush mounted on a top surface of the cam gear within an area surrounded by the raised annular ring;
a cam switch stator provided with a protruded cylindrical drum on a bottom surface thereof; and a circuit board located on a bottom surface of the cylindrical drum.
2. A video cassette recorder provided with the cam switch as claimed in claim 1.
Applications Claiming Priority (2)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| KR33754/1994-U | 1994-12-13 | ||
| KR2019940033754U KR200160725Y1 (en) | 1994-12-13 | 1994-12-13 | Cam switch for use in a tape recorder |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CN1136702A true CN1136702A (en) | 1996-11-27 |
Family
ID=19401064
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN95117559A Pending CN1136702A (en) | 1994-12-13 | 1995-11-29 | Cam switch for cassette magnetic tape vedeo recorder |
Country Status (3)
| Country | Link |
|---|---|
| JP (1) | JPH08235682A (en) |
| KR (1) | KR200160725Y1 (en) |
| CN (1) | CN1136702A (en) |
Families Citing this family (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| KR100420004B1 (en) * | 2001-09-19 | 2004-03-02 | 주식회사 대우일렉트로닉스 | Mode change device and method of vcr |
| KR100485825B1 (en) * | 2002-11-05 | 2005-04-28 | 삼성전자주식회사 | Mode-switch apparatus for magnetic recording/reading apparatus |
-
1994
- 1994-12-13 KR KR2019940033754U patent/KR200160725Y1/en not_active IP Right Cessation
-
1995
- 1995-11-27 JP JP7331083A patent/JPH08235682A/en active Pending
- 1995-11-29 CN CN95117559A patent/CN1136702A/en active Pending
Also Published As
| Publication number | Publication date |
|---|---|
| KR200160725Y1 (en) | 1999-11-15 |
| KR960024803U (en) | 1996-07-22 |
| JPH08235682A (en) | 1996-09-13 |
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Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| C06 | Publication | ||
| PB01 | Publication | ||
| C10 | Entry into substantive examination | ||
| SE01 | Entry into force of request for substantive examination | ||
| C02 | Deemed withdrawal of patent application after publication (patent law 2001) | ||
| WD01 | Invention patent application deemed withdrawn after publication |