GB2159279A - Tachogenerators - Google Patents
Tachogenerators Download PDFInfo
- Publication number
- GB2159279A GB2159279A GB08502122A GB8502122A GB2159279A GB 2159279 A GB2159279 A GB 2159279A GB 08502122 A GB08502122 A GB 08502122A GB 8502122 A GB8502122 A GB 8502122A GB 2159279 A GB2159279 A GB 2159279A
- Authority
- GB
- United Kingdom
- Prior art keywords
- rotary cylinder
- detecting
- motor
- cylinder structure
- upper drum
- 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.)
- Granted
Links
- 238000004519 manufacturing process Methods 0.000 claims description 3
- 230000000694 effects Effects 0.000 description 2
- YSGQGNQWBLYHPE-CFUSNLFHSA-N (7r,8r,9s,10r,13s,14s,17s)-17-hydroxy-7,13-dimethyl-2,6,7,8,9,10,11,12,14,15,16,17-dodecahydro-1h-cyclopenta[a]phenanthren-3-one Chemical compound C1C[C@]2(C)[C@@H](O)CC[C@H]2[C@@H]2[C@H](C)CC3=CC(=O)CC[C@@H]3[C@H]21 YSGQGNQWBLYHPE-CFUSNLFHSA-N 0.000 description 1
- 238000010276 construction Methods 0.000 description 1
Classifications
-
- H—ELECTRICITY
- H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
- H02K—DYNAMO-ELECTRIC MACHINES
- H02K29/00—Motors or generators having non-mechanical commutating devices, e.g. discharge tubes or semiconductor devices
- H02K29/14—Motors or generators having non-mechanical commutating devices, e.g. discharge tubes or semiconductor devices with speed sensing devices
-
- G—PHYSICS
- G01—MEASURING; TESTING
- G01P—MEASURING LINEAR OR ANGULAR SPEED, ACCELERATION, DECELERATION, OR SHOCK; INDICATING PRESENCE, ABSENCE, OR DIRECTION, OF MOVEMENT
- G01P3/00—Measuring linear or angular speed; Measuring differences of linear or angular speeds
- G01P3/42—Devices characterised by the use of electric or magnetic means
- G01P3/44—Devices characterised by the use of electric or magnetic means for measuring angular speed
- G01P3/48—Devices characterised by the use of electric or magnetic means for measuring angular speed by measuring frequency of generated current or voltage
- G01P3/481—Devices characterised by the use of electric or magnetic means for measuring angular speed by measuring frequency of generated current or voltage of pulse signals
- G01P3/487—Devices characterised by the use of electric or magnetic means for measuring angular speed by measuring frequency of generated current or voltage of pulse signals delivered by rotating magnets
-
- 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
- G11B15/60—Guiding record carrier
- G11B15/61—Guiding record carrier on drum, e.g. drum containing rotating heads
-
- G—PHYSICS
- G11—INFORMATION STORAGE
- G11B—INFORMATION STORAGE BASED ON RELATIVE MOVEMENT BETWEEN RECORD CARRIER AND TRANSDUCER
- G11B5/00—Recording by magnetisation or demagnetisation of a record carrier; Reproducing by magnetic means; Record carriers therefor
- G11B5/48—Disposition or mounting of heads or head supports relative to record carriers ; arrangements of heads, e.g. for scanning the record carrier to increase the relative speed
- G11B5/52—Disposition or mounting of heads or head supports relative to record carriers ; arrangements of heads, e.g. for scanning the record carrier to increase the relative speed with simultaneous movement of head and record carrier, e.g. rotation of head
- G11B5/53—Disposition or mounting of heads on rotating support
-
- 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
- G11B15/46—Controlling, regulating, or indicating speed
- G11B15/467—Controlling, regulating, or indicating speed in arrangements for recording or reproducing wherein both record carriers and heads are driven
- G11B15/473—Controlling, regulating, or indicating speed in arrangements for recording or reproducing wherein both record carriers and heads are driven by controlling the speed of the heads
- G11B15/4731—Controlling, regulating, or indicating speed in arrangements for recording or reproducing wherein both record carriers and heads are driven by controlling the speed of the heads control of headwheel rotation
Landscapes
- Engineering & Computer Science (AREA)
- Power Engineering (AREA)
- Physics & Mathematics (AREA)
- General Physics & Mathematics (AREA)
- Brushless Motors (AREA)
Abstract
A rotary cylinder structure for use with a VTR or DAT cassette tape recorder, is arranged in its entirety at an inclination with respect to a vertical axis. The structure comprises: an upper drum (1) mounting a head (3) thereon and forming a moving part; a lower drum (2) arranged to face the upper drum (1) and forming a stationary part; a motor (13) for turning the upper drum (1); and r.p.m. detecting magnet (11) mounted in the motor for revolving in accordance with the revolutions of the motor; and an r.p.m. detecting circuit (16) arranged to face the r.p.m. detecting magnet (11) for outputting a signal in accordance with the revolutions of the r.p.m. detecting magnet (11). The r.p.m. detecting circuit (16) is formed as less than a circle on the side adjacent the axis of rotation so that it is kept away from contact with the chassis (15) of the cassette tape recorder. As a result, the height of said rotary cylinder structure can be reduced so long as the r.p.m. detecting magnet (11) fails to contact with the chassis (15). <IMAGE>
Description
SPECIFICATION
Rotary cylinder
BACKGROUND OF THE INVENTION
Field of the Invention
The present invention relates to a rotary cylinder for use in a VTR or DAT cassette tape recorder or the like and, more particularly, a structure of the rotary cylinder of the above type.
Description of the Prior Art
Before entering into detail description of the present invention, cursory review of the prior art will be made with reference to the accompanying drawings. Figs. 3 and 4(a) and (b) are explanatory views showing a rotary cylinder of the prior art: Fig. 3 is a longitudinal section; Fig. 4(a) is a schematic side elevation exemplifying a motor portion; and Fig. 4(b) is a back view of Fig. 4(a). In these Figures: reference numeral 1 indicates an upper drum forming a moving part; numeral 2 indicates a lower drum forming a stationary part; numeral 3 indicates a head mounted on the upper drum 1; and numeral 4 indicates a shaft for turning the upper drum 1. This shaft 4 is borne rotatably in bearings 5 which are mounted in the lower drum 2.This shaft 4, i.e., its entirety including the upper drum 1 and the lower drum 2 is arranged to be inclined with respect to a vertical axis. Incidentally, numeral 6 indicates the rotor of a rotary transformer mounted in the upper drum 1, and numeral 7 indicates the stator of said rotary transformer mounted in the lower drum 2. Moreover, numeral 8 indicates a coil, and numeral 9 indicates a rotor magnet. This rotor magnet 9 is mounted on a rotor in a manner to face the coil 8. Incidentally, the aforementioned shaft 4 is held integrally with the rotor 10. The coil 8, the rotor magnet 9, the rotor 10 and the shaft 4 thus far described construct together a motor for turning the upper drum 1 Indicated at numeral 11 is an r.p.m.
detecting magnet mounted on the lower portion of the rotor magnet 9. Indicated at numeral 12 is an r.p:m. detecting base which is mounted on the casing 13 of the motor, for example. This r.p.m. detecting base 12 is formed with a radial circuit pattern 14, as shown in Fig. 4(b), at its side facing the r.p.m. detecting magnet 11.
In the rotary cylinder thus constructed, the upper drum 1 is turned through the shaft 4 by driving the motor so that recording or reproduction can be performed in or from a not-shown tape to be brought into contact with a circumferential portion of the head 3.
In accordance with the revolutions of the rotor magnet 9, i.e:, the revolutions of the r.p.m.
detecting magnet 11 integrated with that rotor magnet 9, a pulsing signal is outputted to a not-shown controller from the relationship between the number of the poles of said r.p.m. detecting magnet 11 and the number of the radii of the circuit pattern 14 of the r.p.m. detecting base 12 so that the r.p.m. of the upper drum 1 is detected. The controller conducts the motor control so that the r.p.m.
may take a proper value.
Incidentally, in the rotary cylinder thus constructed, the r.p.m. detecting base 12 is basically shaped into a flat ring form, as shown in
Figs: 4(a) and (b). Thus, in case this rotary cylinder is attached to a chassis 15, as shown in Fig. 3, its height H is enlarged from the abutting relationship between the chassis 15 and that edge 1 2a of that r:p:m: detecting base 12, which is positioned at an inclined side 18, so that a recording and reproducing apparatus said rotary cylinder is to be mounted in, such as a VTR has its total height increased to invite a disadvantage that it cannot be small-sized.
Incidentally the detecting accuracy of the r.p.m. to be detected by the r p.m. detecting magnet 11 and the r.p.m. detecting base 12 is influenced by the flatness of that surface of the r.p:m. detecting base 12, which faces the r:p.m. detecting magnet 11: This makes it necessary to fabricate the r.p.m. detecting base 12 so that the flatness may be sufficiently ensured all over the surface. In the prior art, therefore, that r.p.m. detecting base 12 has its fabrication step number and cost raised.
SUMMARY OF THE INVENTION
The present invention has been conceived in view of the real situation of the prior art and has an object to provide a rotary cylinder structure which can have a smaller height and reduce the number of steps of fabricating the r.p.m. detecting base.
In order to achieve this object, according to the present invention, there is provided a rotary cylinder arranged to be inclined its its entirety with respect to a vertical axis and comprising: an upper drum mounting a head thereon and forming a moving part; a lower drum arranged to face said upper drum and forming a stationary part; a motor for turning said upper drum; an r.p.m. detecting magnet mounted in said motor for revolving in accordance with the revolutions of said motor; and an r.p.m. detecting base arranged to said r.p.m. detecting magnet for outputting a signal in accordance with the revolutions of said r.p.m. detecting magnet, wherein the improvement resides in that said r.p.m. detecting base is formed with a cutaway portion at its portion located at said inclined side so that it is kept away from contact with a chassis, whereby the height of said rotary cylinder structure can be reduced so far as said r.p.m.
detecting magnet fails to contact with said chassis.
BRIEF DESCRIPTION OF THE DRAWINGS
Other objects, features and advantages of the present invention will become apparent from the following description taken with reference to the accompanying drawings, in which:
Fig: 1 is a longitudinal section showing one embodiment of the rotary cylinder structure of the present invention;
Fig. 2(a) is a schematic side elevation exemplifying the motor portion of the rotary cylinder structure of Fig. 1;
Fig. 2(b) is a back view of Fig: 2(a);
Fig. 3 is similar to Fig. 1 but shows the rotary cylinder structure of the prior art;
Fig. 4(a) is a schematic side elevation exemplifying the motor portion of the rotary cylinder structure of Fig. 3; and
Fig 4(b) is a back view of Fig. 4(a).
DESCRIPTION OF THE PREFERRED EMBODI
MENT
The rotary cylinder according to the present invention will be described in the following with reference to the accompanying drawing.
Figs. 1 and 2(a) and (b) are explanatory views showing one embodiment of the present invention: Fig: 1 is a longitudinal section; Fig.
2(a) is a schematic side elevation exemplifying a motor portion; and Fig. 2(b) is a back view of Fig. 2(a). Incidentally, in these Figures: the same as the aforementioned parts are indicated at identical reference numerals. That is to say: numeral 1 indicates the upper drum; numeral 2 the lower drum; numeral 3 the head; numeral 4 the shaft; numeral 5 the bearings; numerals 6 and 7 the rotor and stator forming the rotary transformer, respectively; numerals 8 and 9 the coil and the rotor magnet constructing the motor; numeral 10 the rotor; numeral 11 the r.p.m. detecting magnet; numeral 13 the casing of the motor; and numeral 15 the chassis in which this rotary cylinder is to be mounted.
In these Figures, on the other hand, reference numeral 16 indicates an r.p.m. detecting base which is arranged to face the r.p.m.
detecting magnet 11. The r.p.m. detecting base is formed at its one side, as shown in
Fig. 2(b), with a cut-away portion 17 and is mounted in the casing 13 of the motor such that the cut-away portion 17 is positioned at the inclined side 18 of said rotary cylinder, as shown in Figs. 1 and 2(a). Incidentally, the cut-away portion 17 is set, for example, one half as large as the whole size of the aforementioned r.p.m. detecting base 12, as shown in Fig. 4(b). Moreover, the r.p.m.
detecting base 16 is formed with a radial circuit pattern 19 at its side facing the r.p.m.
detecting magnet 11.
In this rotary cylinder, like the aforementioned one shown in Figs. 3 and 4(a) and (b), the upper drum 1 is turned by the drive of the motor so that the recording or reproduction can be conducted in or from a not-shown tape. In accordance with the revolutions of the r.p.m. detecting magnet 11 which is made rotatable integrally with the rotor magnet 9, moreover, a pulsing signal is outputted to a not-shown controller through a not-shown lead line, which is connected with the circuit pattern 10 of the r.p.m. detecting base 16, so that the r.p.m. of the motor, i.e., the r.p.m. of the upper drum 1 is detected.
In the rotary cylinder thus constructed, as has been described above, the r.p.m. detecting base 16 is formed with the cut-away portion 17 at its portion located at the inclined side 18 of said rotary cylinder. As a result, the r.p.m. detecting base 16 does not come into contact with the chassis 15 so that the rotary cylinder can have its height Ho set at a small value so long as the r.p.m. detecting magnet 11 does not contact with the chassis 15.
On the other hand, the cut-away portion 17 of the r.p.m. detecting base 16 is set one half as large as the whole size of the r.p.m.
detecting base 12 shown in Fig. 4(b). This makes it easy to ensure the flatness of the surface, as compared with the r.p.m. detecting base 16 which is formed wholly into the flat ring shape, as shown in Fig. 4(b). As a result, it is possible to reduce the number of the steps of fabricating that r.p.m. detecting base 16.
Incidentally, in the foregoing embodiment, the size of the cut-away portion 17 is set one half as large as the whole size of the r.p.m.
detecting base 12 shown in Fig. 4(b). Despite of this fact, however, the present invention should not be limited to that embodiment but the size of that cut-away portion 17 can be one third, two thirds, three fourths and so on as large as said whole size, if necessary.
Since the rotary cylinder of the present invention has the construction thus far described, its height can be reduced. This results in an effect that the size of the recording and reproducing apparatus this rotary cylinder is to be mounted in can be reduced. There arises another effect that the number of steps of fabricating the r.p.m. detecting base can be reduced so that its fabrication cost can be made lower than that of the prior art.
Claims (5)
1. A rotary cylinder structure arranged to be inclined its its entirety with respect to a vertical axis and comprising: an upper drum mounting a head thereon and forming a moving part; a lower drum arranged to face said upper drum and forming a stationary part; a motor for turning said upper drum; an r.p.m.
detecting magnet mounted in said motor for revolving in accordance with the revolutions of said motor; and an r.p.m. detecting base arranged to face said r.p.m. detecting magnet for outputting a signal in accordance with the revolutions of said r.p.m. detecting magnet,
wherein the improvement resides in that said r.p.m. detecting base is formed with a cut-away portion at its portion located at said inclined side so that it is kept away from contact with a chassis, whereby the height of said rotary cylinder structure can be reduced so far as said r.p.m. detecting magnet fails to contact with said chassis.
2. A rotary cylinder structure according to
Claim 1, wherein said cut-away portion is set one half as large as the whole size of said r.p.m. detecting base so that said r.p.m. detecting base can easily have its remaining portion ensured in its surface flatness to reduce the number of its fabrication steps.
3. A rotary cylinder structure according to
Claim 1, wherein said cut-away portion is set at a value selected from the group of consisting of one third, two thirds and three fourths.
4. A rotary cylinder structure according to
Claim 1, wherein said motor includes a shaft borne rotatably in said lower drum for turning said upper drum, a coil, a rotor integrally holding said shaft, and a rotor magnet mounted on said rotor and positioned to face said coil.
5. A rotary cylinder structure substantially as hereinbefore described, with reference to
Figures 1 and 2 of the accompanying drawings.
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP7573284U JPS60192115U (en) | 1984-05-25 | 1984-05-25 | rotating cylinder |
Publications (3)
| Publication Number | Publication Date |
|---|---|
| GB8502122D0 GB8502122D0 (en) | 1985-02-27 |
| GB2159279A true GB2159279A (en) | 1985-11-27 |
| GB2159279B GB2159279B (en) | 1988-10-26 |
Family
ID=13584733
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| GB08502122A Expired GB2159279B (en) | 1984-05-25 | 1985-01-29 | Rotary cylinder structures |
Country Status (2)
| Country | Link |
|---|---|
| JP (1) | JPS60192115U (en) |
| GB (1) | GB2159279B (en) |
-
1984
- 1984-05-25 JP JP7573284U patent/JPS60192115U/en active Granted
-
1985
- 1985-01-29 GB GB08502122A patent/GB2159279B/en not_active Expired
Also Published As
| Publication number | Publication date |
|---|---|
| GB8502122D0 (en) | 1985-02-27 |
| JPS60192115U (en) | 1985-12-20 |
| GB2159279B (en) | 1988-10-26 |
| JPH0110781Y2 (en) | 1989-03-28 |
Similar Documents
| Publication | Publication Date | Title |
|---|---|---|
| JP2922633B2 (en) | Disk unit | |
| US5245235A (en) | Motor having index detection mechanism used for disc apparatus and disc apparatus using such a motor | |
| US4347536A (en) | Rotary cylinder apparatus | |
| GB2159279A (en) | Tachogenerators | |
| JPH01271965A (en) | Supporter/driver for recording disc | |
| JPH0244364Y2 (en) | ||
| KR0176521B1 (en) | Rotary Headdrum Assembly of Tape Recorder | |
| JPH07286621A (en) | Rotating magnetic head device | |
| JPS639009A (en) | Rotary head assembly for magnetic recording and reproducing device | |
| JPH0452808Y2 (en) | ||
| JP2501511Y2 (en) | Rotating head drum device | |
| JP2621640B2 (en) | Electric motor | |
| JPH08203042A (en) | Rotating drum device | |
| JPH0644721A (en) | Magnetic disk device | |
| JPS6218642A (en) | Cylinder device | |
| JPS642534Y2 (en) | ||
| JPH0526246B2 (en) | ||
| JPS6177118A (en) | rotating magnetic head drum | |
| JPH02177114A (en) | Rotary head drum device | |
| JPS58134224A (en) | rotating device | |
| JPH05182312A (en) | Magnetic recording / reproducing device | |
| JPH02252180A (en) | memory disk device | |
| KR19980069615A (en) | Rotating drum of head drum assembly | |
| JPH0495285A (en) | Magnetic disk | |
| JPS59135673A (en) | magnetic recording and reproducing device |
Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| PCNP | Patent ceased through non-payment of renewal fee |
Effective date: 19930129 |