PHILIPS VR6485/01 Switched-mode self oscillating supply voltage circuit:POWER SUPPLY (PHILIPS SOPS - Self Oscillating Power Supply)
1. A switched-mode self-oscillating supply voltage circuit for converting an input voltage into an output d.c. voltage which is substantially independent of variations of the input voltage and/or of a load connected to the terminals of the output voltage, comprising a transformer having a primary and a feedback winding, a first controllable switch connected in series with the primary winding, the series arrangement thus formed being coupled between terminals for the input voltage, a second controllable switch co
2. A supply voltage circuit as claimed in claim 1, further comprising a resistor included between the connection of the starting network to the second switch and a turn-off capacitor present in the connection to the control electrode of the first switch.
3. A supply voltage circuit as claimed in claim 2, characterized in that the second controllable switch comprises a thyristor having a main current path included in the control electrode connection of the first controllable switch, said thyristor having a first control gate electrode for adjusting the turn-off instant of the first switch and a second control electrode to which the starting network and the resistor are connected.
4. A supply voltage circuit as claimed in claim 1, characterized in that a resistor is included in the connection to the control electrode of the second controllable switch so that a current flows through said resistor in the stand-by state of a value sufficient to cut-off the first controllable switch.
Such a supply voltage circuit is disclosed in German Patent Application No. 2,651,196. With this prior art circuit supply energy can be applied in the operating state to the different portions of a television receiver. In the stand-by state the majority of the output voltages of the circuit are so low that the receiver is substantially in the switched-off condition. In the prior art circuit the starting network is formed by a resistor connected to the unstabilized input voltage and through which on turn-on of the circuit a current flows via the feedback winding to the control electrode of the first controllable switch, which is a switching transistor, and brings it to and maintains it in the conductive state, as a result of which the circuit can start.
In the stand-by state the transistor is non-conducting in a large part of the period of the generated oscillation so that little energy is stored in the transformer. However, the starting resistor is connected via a diode to the second controllable switch, which is a thyristor. As the sum of the voltages across these elements is higher than the base-emitter threshold voltage of the transistor, the diode and the thyristor cannot simultaneously carry current. This implies that current flows through the starting resistor to the base of the transistor via the feedback winding after a capacitor connected to the feedback winding has been charged.
The invention has for its object to provide an improved circuit of the same type in which in the stand-by state the supply energy applied to the load is reduced to zero. The prior art circuit cannot be improved in this respect without the use of mechanical switches, for example relays. According to the invention, the switched-mode self-oscillating supply voltage circuit does not comprise such relays and is characterized in that it further comprises means for adjusting the control voltage in the stand-by state to a value at which the first controllable switch is cut-off. A connection which carries current during the conduction period of the second controllable switch is provided
The invention is based on the recognition that the prior art supply voltage circuit cannot oscillate, so that the energy supplied by it is zero, if the control voltage obtains a value as referred to, while the starting network is connected in such a manner that in the stand-by state no current can flow through it to the control electrode of the first controllable switch.
It should be noted that in the said German Patent Application the starting network is in the form of a resistor which is connected to an unstabilized input d.c. voltage. It is, however, known, for example, from German Patent Specification No. 2,417,628 to employ for this purpose a rectifier network connected to an a.c. voltage from which the said input d.c. voltage is derived by rectification.
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The invention will now be further described by way of example with reference to the accompanying drawing, which shows a basic circuit diagram of a switched-mode self-oscillating supply voltage circuit.
The self-oscillating supply circuit shown in the FIGURE comprises a npn-switching transistor Tr1 having its collector connected to the primary winding L1 of a transformer T, while the emitter is connected to ground via a small resistor R1, for example 1.5 Ohm. Resistor R1 is decoupled for the high frequencies by means of a 150 nF capacitor C1. One end of winding L1 is connected to a conductor which carries an unstabilized input d.c. voltage V B of, for example, 300 V. Voltage V B has a negative rail connected to ground and is derived from the electric power supply by rectification. One end of a feedback winding L2 is connected to the base of transistor Tr1 via the parallel arrangement of a small inductance L3 and a damping resistor R2. A terminal of a 47 μF capacitor C2 is connected to the junction of the elements L2, L3 and R2. The series arrangement of a diode D1 and a 2.2 Ohm-limiting resistor R3 is arranged between the other terminal of capacitor C2 and the other end of winding L2 and the series arrangement of a resistor R4 of 12 Ohm and a diode D2 is arranged between the same end of winding L2 and the emitter of transistor Tr1. A 150 nF capacitor C3 is connected in parallel with diode D2. The anode of diode D1 is connected to that end of winding L2 which is not connected to capacitor C2, while the anode of diode D2 is connected to the emitter of transistor Tr1. In the FIGURE the winding sense of windings L1 and L2 is indicated by means of dots.
The junction of capacitor C2 and resistor R3 is connected to a 100 Ohm resistor R5 and to the emitter of a pnp-transistor Tr2. The base of transistor Tr2 is connected to the other terminal of resistor R5 and to the collector of an npn-transistor Tr3, whose emitter is connected to ground. The base of Tr3 is connected to the collector of transistor Tr2. Transistors Tr2 and Tr3 form an artificial thyristor, i.e. a controllable diode whose anode is the emitter of transistor Tr2 while the cathode is the emitter of transistor Tr3. The base of transistor Tr2 is the anode gate and the base of transistor Tr3 is the cathode gate of the thyristor formed. Between the last-mentioned base and the emitter of transistor Tr1 there is arranged the series network of a 2.2 kOhm resistor R6 with the parallel arrangement of a 2.2 kOhm resistor R7 and a 100 μF capacitor C4. The series arrangement of a diode D11 and a 220 Ohm limiting resistor R19 is arranged between the junction of components R6, R7 and C4 and the junction of components C2, L2, R2 and L3. The cathode of diode D11 is connected to capacitor C2.
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Secondary windings L4, L5 and L6 are provided on the core of transformer T with the indicated winding senses. When transistor Tr1 is turned off, a current which recharges a smoothing capacitor C5, C6 or C7 via a rectifier D3, D4 or D5 flows through each of these windings. The voltages across these capacitors are the output voltages of the supply circuit for loads connectable thereto. These loads, which are not shown in the FIGURE, are, for example, portions of a television receiver.
In parallel with winding L1 there is the series network of a 2.2 nF tuning capacitor C8 and a 100 Ohm limiting resistor R8. The anode of a diode D6 is connected to the junction of components R8 and C8, while the cathode is connected to the other terminal of resistor R8. Winding L1 and capacitor C8 form a resonant circuit across which an oscillation is produced after windings L4, L5 and L6 have become currentless. At a later instant the current through circuit L1, C8 reverses its direction. As a result thereof a current is generated in winding L2 which flows via diode D2 and resistor R4 to the base of transistor Tr1 and makes this transistor conductive and maintains it in this state. The dissipation in resistor R8 is reduced by means of diode D6. A clamping network formed by the parallel arrangement of a 22 kOhm resistor R9 and a 120 nF capacitor C9 is arranged in series with a diode D7. This whole assembly is in parallel with winding L1 and cuts-off parasitic oscillations which would be produced during the period of time in which transistor Tr1 is non-conductive. The output voltages of the supply circuit are kept substantially constant in spite of variations of voltage V B and/or the loads, thanks to a control of the turning-on instant of thyrisistor Tr2, Tr3. For this purpose the emitter of a light-sensitive transistor Tr4 is connected to the base of transistor Tr3. The collector of transistor Tr4 is connected via a resistor R10 to the conductor which carries the voltage V B and to a Zener diode Z1 which has a positive voltage of approximately 7.5 V, while the base is unconnected. The other end of diode Z1 is connected to ground. A light-emitting diode D8, whose cathode is connected to the collector of an npn-transistor Tr5, is optically coupled to transistor Tr4. By means of a potentiometer R11 the base of transistor Tr5 can be adjusted to a d.c. voltage which is derived from the voltage V 0 of approximately 130 V across capacitor C6. The anode of diode D8 is connected to a d.c. voltage V 1 of approximately 13 V. A resistor R12 is also connected to voltage V 1 , the other end of the resistor being connected to the emitter of transistor Tr5, to the cathode of a Zener diode Z2 which has a voltage of approximately 7.5 V and to a smoothing capacitor C10. The other ends of diode Z2 and capacitor C10 are connected to ground. Voltage V1 can be generated by means of a transformer connected to the electric AC supply and a rectifier, which are not shown for the sake of simplicity, more specifically for a remote control to which constantly supply energy is always applied, even when the majority of the components of the receiver in what is referred to as the stand-by state are not supplied with supply energy.
A portion of voltage V 0 is compared with the voltage of diode Z2 by means of transistor Tr5. The measured difference determines the collector current of transistor Tr5 and consequently the emitter current of transistor Tr4. This emitter current produces across resistor R6 a voltage drop whose polarity is the opposite of the polarity of the voltage source formed by resistor R7 and capacitor C4. Under the influence of this voltage drop the turn-on instant of thyristor Tr2, Tr3 is controlled as a function of voltage V 0 . If, for example, voltage V 0 tends to decrease owing to an increasing load thereon and/or in response to a decrease in voltage V B , then the collector current of transi
The circuit is protected from overvoltage. This is ensured by a thyristor which is formed by a pnp-transistor Tr6 and an npn-transistor Tr7. The anode of a diode D9 is connected to the junction of components R3 and C2 and the cathode to the base of transistor Tr6 and to the collector of transistor Tr7. The base of transistor Tr7, which base is connected to the collector of transistor Tr6, is connected via a zener diode Z3 to a voltage which, by means of a potentiometer R13 is adjusted to a value derived from the voltage across capacitor C7. The emitter of transistor Tr6 also is connected to the voltage of capacitor C7, more specifically via a resistor R14 and a diode D10. If this voltage increases to above a predetermined value then thyristor Tr6, Tr7 becomes conductive. Since the emitter of transistor Tr7 is connected to ground, the voltage at its collector becomes very low, as a result of which diode D9 becomes conductive, which keeps transistor Tr1 in the non-conducting state. This situation is maintained as long as thyristor Tr6, Tr7 continues to conduct. This conduction time is predominantly determined by the values of capacitor C7, resistor R14 and a resistor R15 connected between the base and the emitter of transistor Tr6. A thyristor is advantageously used here to render it possible to switch off a large current even with a low level signal and to obtain the required hysteresis.
The circuit comprises a 1 MOhm starting resistor R16, one end of which is connected to the base of transistor Tr2 and the other end to the conductor which carries the voltage V B . Upon turn-on of the circuit current flows through resistors R16 and R5 and through capacitor C2, which has as yet no charge, to the base of transistor Tr1. The voltage drop thus produced across resistor R5 keeps transistor Tr2, and consequently also transistor Tr3, in the non-conductive state, while transistor Tr1 is made conductive and is maintained so by this current. Current also flows through winding L2. In this manner the circuit can start as energy is built up in transformer T.
The supply circuit can be brought into the stand-by state by making an npn-transistor Tr8, which is non-conductive in the operating state, conductive. The emitter of transistor Tr8 is connected to ground while the collector is connected to the collector of transistor Tr5 via a 1.8 kOhm resistor R17. A resistor R18 has one end connected to the base of transistor Tr8 and the other end, either in the operating state to ground, or in the stand-by state to a positive voltage of, for example, 5 V. Transistor Tr8 conducts in response to this voltage. An additional, large current flows through diode D8 and consequently also through transistor Tr4, resulting in thyristor Tr2, Tr3 being made conductive and transistor Tr1 being made non-conductive and maintained so. So to all appearances a large control current is obtained causing the duty cycle to be reduced to zero. A condition for a correct operation is that the emitter current of transistor Tr4 be sufficiently large in all circumstances, which implies that the voltage drop produced across resistor R6 by this current is always higher than the sum of the voltage across voltage source R7, C4, of the base-emitter threshold voltage of transistor Tr3 in the conductive state thereof, and of the voltage at the emitter of transistor Tr1. So the said voltage drop must be higher than the sum of the first two voltages, which corresponds to the worst dimensioning case in which the stand-by state is initiated while transistor Tr1 is in the non-conductive state.
In the foregoing a circuit is described which may be considered to be a switched-mode supply voltage circuit of the parallel ("flyback") type. It will be obvious that the invention may alternatively be used in supply voltage circuits of a different type, for example converters of the type commonly referred to as up-converters. It will also be obvious that transistor Tr1 may be replaced by an equivalent switch, for example a gate-turn-off switch.
G-DECK Mechanism Magnetic tape recording and/or reproducing apparatus:
In a recording and / or reproducing apparatus (1) for a magnetic tape (54) containing the cassette (2) which an adjustable between a loading position and an operating position the cassette holding means (10) for transferring a set manually in the device box to an operating position on a device, adjustable between a thread-out position and a threading tape-threading device (69) for wrapping loops of the magnetic tape (54) to a scanner (70) for the same and at least one adjustable between at least two operating positions of tape operating means (58) for performing a tape operation in at least one of its operating positions, which the adjustment is made, both the cassette holding means (10) and the threading device (69) and the tape drive operating device (58) via a motor-driven differential gear (118) to give a high ease of use of the device results in a space-saving and easy assembly.
tape transporting means comprising a capstan for transporting said magnetic tape at a constant speed in cooperation with a pinch roller;
a single motor for driving said tape transporting means to rotate said capstan;
cassette loading means for mounting said tape cassette at a predetermined position;
tape loading means reciprocatable between an inoperative position where said magnetic tape is within said tape cassette and an operative position where said magnetic tape is drawn out of said tape cassette and loaded in a specific tape path;
operating mode changing means for changing operating mode of said apparatus from one operating mode to another;
tape winding means comprising a pair of reel turntables engageable with said reels for rotating said reels;
reel turntable driving means for transmitting a rotational driving force of said motor to said tape winding means to rotate said reel turntables;
clutch means connected to said motor for transmitting intermittently the rotational driving force of said motor;
an actuator connected to said clutch for driving said clutch means; and
driving selecting means connectable between said clutch and said cassette loading means; said tape loading means and said operating mode changing means for transmitting the rotational driving force of said motor from said clutch means selectively to said cassette loading means or to said tape loading means and said operating mode changing means,
whereby said cassette loading means, said tape loading means, said operating mode changing means, said tape transporting means, and said tape winding means are driven by said single motor.
2. The apparatus according to claim 1, wherein said driving selecting means is simultaneously connected to said operating mode changing means, and said tape loading means.
3. The apparatus according to claim 1, further comprising brake controlling means having a brake for applying a brake effect to said reel turntables and to which said actuating means is connected for operating said brake controlling means and said operating mode changing means simultaneously to, when said tape loading means is in said inoperative position, cause said actuator to actuate said brakes, and for, when said operating mode changing means is actuated to change said tape loading means to the operative position, not to apply said brake effect to said reel turntables regardless of the condition of said actuator.
4. The apparatus according to claim 1, wherein said operating mode changing means comprises a cam driven by said motor for changing the operating mode of said apparatus and an operation member driven by said cam to move to plural positions corresponding to plural operating modes of said apparatus.
5. The apparatus according to claim 1, wherein said reel turntable driving means comprises intermittently rotating means which transmits said rotational driving force of said motor intermittently to said reel turntables.
6. The apparatus according to claim 1, wherein said reel turntable driving means comprises torque controlling means by which a driving torque for said reel turntables from said motor is controlled to be larger when said tape loading means is in said inoperative position than when in said operative position.
7. The apparatus according to claim 6, further com
8. The apparatus according to claim 7, wherein said torque controlling means is driven by said rotatable disc having said tape loading cam.
9. The apparatus according to claim 1, wherein said motor is a brushless motor.
10. The apparatus according to claim 9, wherein said motor has a spindle which constitutes said capstan.
11. The apparatus according to claim 1, wherein said operating mode changing means comprises a pinch roller press-contact means for pressing said pinch roller to said capstan with said magnetic tape therebetween, said pinch roller press-contact means comprising a driving member which reciprocates said pinch roller between a first position where said pinch roller does not hinder said tape loading means from drawing out said magnetic tape and a second position inside a tape loop of said magnetic tape drawn out of said tape loading means and drives said pinch roller to a third position where said pinch roller is brought into press-contact with said capstan with said magnetic tape therebetween.
12. The apparatus according to claim 1, wherein said driving selecting means comprises: a differential gear mechanism including a first rotatable disc connected to said cassette lo
Description:
BACKGROUND OF THE INVENTION
1. Field of the Invention
This inve
2. Description of the Prior Art
Recently a construction which can decrease the number of motors for driving the MTRR apparatus has been proposed for answering the increasing demand for low cost, light weight, and low power consumption MTRR apparatuses. Japanese Laid-Open Patent Application No. 56-114154 discloses a construction which drives with one motor both operating mode changing means for changing conditions of the MTRR apparatus and tape loading means for drawing a magnetic tape out of a tape cassette and winding it at a predetermined angle around a guide drum carrying a rotary magnetic head. Although this construction makes it possible to drive with one motor both the tape loading means and the operating mode changing means for operations such as, a pinch roller press-contact operation (a pinch roller is brought into press-contact with a capstan with
SUMMARY OF THE INVENTION
An object of this invention is to provide a MTRR apparatus which performs with one motor the cassette loading operation, the tape loading operation, the operating mode changing operation and the magnetic tape transporting operation.
This object is accomplished by a MTRR apparatus which uses a tape cassette having therein tape reels on which a magnetic tape is wound and comprises: a capstan for transporting said magne
The above and other objects, features and advantages of the present invention will become apparent from the following detailed description taken in conjunction with the accompanying drawings, in which:
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 is a block diagram showing an embodiment of a MTRR apparatus according to this invention.
FIG. 2 is a schematic plan view of the embodiment, in which the position of a tape cassette is indicated by dot-dash lines, in a stopping mode, a fast-forward-winding mode, or a recording/reproducing mode.
FIG. 3 is a schematic sectional view of a mechanism of a reel turntable driving means.
FIG. 4 is a schematic sectional view of a mechanism including a driving selecting means, a tape loading means, and a controlling torque means.
FIGS. 5A, 5B and 5C are diagrams showing relationships between the amount of cam lift and degree of cam rotation.
FIGS. 6A and 6B are schematic sectional views of a mechanism including a clutch selecting means, the driving means and an operating mode changing means.
FIG. 7 is a perspective view of a mechanism of the clutch means.
FIG. 8 is a schematic sectional view of a mechanism including the operating mode changing means, a controlling brake means and a intermittently operable rotating means.
FIG. 9 is a schematic sectional view of a mechanism including the driving selecting means and the tape loading means.
FIG. 10 is a schematic sectional view of a mechanism of a pinch roller press-contact means.
FIG. 11 is a side view of a mechanism including a motor and a driving member for the pinch roller press-contact means.
FIGS. 12A and 12B are schematic top views of a mechanism of the driving selecting means.
FIG. 13 is a side view of a mechanism of a cassette loading means.
FIG. 14 is a block diagram of the apparatus in the stopping mode.
FIG. 15 is a block diagram of the apparatus in the fast-forward-winding mode.
FIG. 16 is a schematic plan view of the apparatus in the fast-forward-winding mode.
FIG. 17 is a schematic plan view of the apparatus in the state where a first rotatable disc and a second rotatable disc rotate to a rotary angle of 170°.
FIG. 18 is a block diagram of the apparatus in the state just before the recording/reproducing mode.
FIG. 19 is a schematic plan view of the apparatus in the state just before the recording/reproducing mode.
FIG. 20 is a block diagram of the apparatus in the recording/reproducing mode.
DESCRIPTION OF THE PREFERRED EMBODIMENT
FIGS. 1, 14, 15, 18 and 20 are block diagrams of an embodiment of the invention, in which lines connecting respective means and components show channels for transmitting the rotational driving force of a motor 501, operation of an actuator 500 or operations of respective means to respective means, thick lines showing the state of the rotational driving force being transmited and/or the operations, thin lines showing the states of being inactivated, and arrows showing the directions of the respective transmissions.
As explanatio
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FIG. 2 is a plan view of the embodiment of the invention, i
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FIGS. 2, 16, 17 and
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An explanation will be given of the reel turntable driving means. Referring to FIG. 2, a pulley 28 having toothed portions 26 and 27 is fitted rotatably onto a shaft 25 mounted on the chassis 1, and is rotatably driven by the motor 24 through a belt 29 stretched around the pulley 28 and a pulley 24a press-fitted onto the capstan 23. Also a support plate 30 for changing the reduction ratio between the motor 24 and both of the reel turntables 4 and 5 is supported rotatably on the shaft 25 as shown in FIG. 3. A gear 32 used in the recording/reproducing mode is fitted rotatably onto a shaft 31 mounted at one end of the support plate 30 and adapted to always engage with the toothed portion 26 integral with the pulley 28, while a gear 34 used in the fast-forward-winding mode is fitted rotatably onto a shaft 33 mounted at the other end of the support plate 30 and adapted to always engage with the toothed portion 27 integral with the pulley 28. A flexible member 35 having at one end a first cam follower 36 is fixed upon the support plate 30 as shown in FIG. 4. Thus the torque controlling means 510, which controls the driving torque of the both reel turntables 4 and 5, comprises the pulley 28, support plate 30, gear 32 and gear 34.
In FIG. 4, the first rotatable disc 37 which drives the tape loading means 508, is fit
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In accordance with the rotation of the first rotatable disc 37 from 0° to 70°, the gear 34 engageable with the toothed portion 27 integral with the pulley 28 engages with the lower part gear 44 so that the driving torque of the motor 24 is directly transmitted to the both reel turntables 4 and 5 but not through the friction member 42 of the torque limiting member 40. As stated above, in accordance with the rotation of the first rotatable disc 37 from 70° to 120°, the support plate 30 turns clockwise around the shaft 25 to disengage the gear 34 from the lower part gear 44, and then allows the gear 32 which engages with the toothed portion 26 integral with the pulley 28 to engage with the upside gear 41, so that after rotation of more than 120°, the gear 32 engages with the upside gear 41. Furthermore the reduction ratio of the gear train consisting of the toothed portion 26, the gear 32 and the upside gear 41 is larger than that of the gear train consisting of the toothed portion 27, the gear 34 and the lower part gear 44. Hence, the torque controlling means 510 is driven and controlled by the first rotatable disc 37 which drives the tape loading means 508 to be discussed below.
The reduction ratio from the upside gear 41 to the reel gear 60 integral with the supply reel turntable 4 is larger than that from the upside gear 41 to the reel gear 58 integral with the take-up reel turntable 5, so as to make the winding torque of the supply reel turntable 4 in the reviewing mode larger than that of the take-up reel turntable 5 in the recording and/or reproducing mode.
Next, an explanation will be given of the actuator 500 and the clutch means 503.
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The rotational driving force of the motor 24 (501 in FIG. 1) is transmitted to the first rotatable disc 37, the second rotatable disc 66 and the third rotatable disc 67 respectively through a first idler gear 62 engageable with the toothed portion 27 integral with the pulley 28, a second idler gear 63 engageable with the first idler gear 62, and the clutch gear 65 engageable with both the second idler gear 63 and a first toothed portion 64a integral with a driving gear 64. The clutch gear 65 is always engageable with the second idler gear 63 and is supported rotatably on a shaft 68 mounted on the chassis 1, is allowed to move upwardly and downwardly along the shaft 68, is always biased downwardly by a compression spring 65a, and is disposed on a first clutch plate 69 fitted rotatably onto a shaft 70 mounted on the chassis 1 as shown in FIGS. 6A and 6B. The first clutch plate 69 has an upper face 69a and a lower face 69b which are different in height as shown in FIGS. 6A, 6B and 7. A slot 72 provided in a second clutch plate 71 which is fitted rotatably onto the shaft 70 and disposed on the first clutch plate 69, engages with a projection 73 provided on the first clutch plate 69, and a torsion spring 75 is disposed between the projection 73 and a projection 74 provided on the second clutch plate 71 as shown in FIG. 7, so that the second clutch plate 71 is always biased counterclockwise, as shown in FIG. 2, to cause the first clutch plate 69 and the second clutch plate 71 to turn integrally with each other around the shaft 70. A slot 78 provided at one end of a turnable lever 77 supported turnably on a shaft 76 mounted on the chassis 1 engages with a pin 79 pr
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In the embodiment of the present invention, the actuator 500 comprises the plunger 82 and the solenoid 81, but it may comprise a motor for obtaining the same effect in this invention.
When the clutch gear 65 does not engage with the first toothed portion 64a due to the abutting of the surfaces of teeth of the clutch gear 65 against that of the first toothed portion 64a regardless of the clutch gear 65 being moved upwardly in FIG. 6 along the shaft 68 by the first clutch plate 69, the first clutch plate 69 stops turning while the second clutch plate 71 turns clockwise around the shaft 70 against the biasing force of the torsion spring 75. And when the clutch gear 65 engages with the first toothed portion 64a, the first clutch plate 6 starts to turn clockwise again around the shaft 70, and the clu
The driving selecting means 504 which drives selectively either the cassette loading means 505 or the operating mode changing means 506 comprises a differential gear mechanism 200 as shown in FIG. 6. An explanation will be given on the differential gear mechanism 200.
The driving gear 64 having the first toothed portion 64a selectively engageable with the clutch gear 65 and a sun gear 64b are fitted freely rotatably onto a shaft 84 mounted on the chassis 1. A plurality of shafts 86 are provided on a retainer gear 85 which is fitted rotatably onto a boss 64c provided on the driving gear 64, and support rotatably the planetary gears 87 on the shafts 86, the planetary gears 87 engaging with the sun gear 64b. And a transmission gear 88 having at the inner periphery an internal toothed portion 88a and at the outer periphery an external toothed portion 88b is fitted rotatably onto the shaft 84, the internal toothed portion 88a engaging with the planetary gears 87. Hence, when the transmission gear 88 is restrained from rotating, the planetary gears 87 are revolved on their axes round the shaft 84 by the rotation of the driving gear 64, the retainer gear 85
The following explanation will be given of the tape loading means 508. The first rotatable disc 37 for driving the tape loading means 508 engages with the retainer gear 85. A second cam follower 91 fixed at one end of an arm 90 supported rotatably on a shaft 89 mounted on the chassis 1 engages with the grooved cam 37b at the rear surface of the first rotatable disc 37 as shown in FIGS. 2 and 9. A sector gear 92 formed on the other end of the arm 90 engages with a first loading gear 94 fitted rotatably onto a shaft 93 mounted on the chassis 1. A second loading gear 95 integral with the first loading gear 94 and rotatable around the shaft 93 engages with a third loading gear 97 fitted onto a shaft 96 mounted on the chassis 1. Thus the loading gear train comprising 94, 95 and 97 rotates in synchronism with the sector gear 92. In FIG. 9, a first arm 98 for rightward loading is fitted rotatably onto the shaft 93. A tension spring 99a is stretched between a spring seat 98a provided at the first arm 98 for rightward loading and a pin 95a mounted on the second loading gear 95, so that the pin
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When the first rotatable disc 37 starts to rotate clockwise from the position in FIG. 2, the second cam follower 91 is not moved during the clockwise rotation of the first rotatable disc 37 from 0° to 150° as
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Next an explanation will be given of the operating mode changing means 506 which drives the pinch roller press-contact means 507, the brake controlling means 514 and the intermittently rotating means 512.
In FIG. 6, the second rotatable disc 6b engageable with the retainer gear 85 is fitted freely-rotatably onto a shaft 112 mounted on the chassis 1 and has at one side a positive cam groove 113 extending through an angle of 360° or more as shown in FIG. 5A for changing the operation mode of the apparatus. A cam follower 116 fixed at one end of a turnable arm 115 which is supported rotatably onto a shaft 114 mounted on the chassis 1 as shown FIG. 2, engages with the cam grooved 113. The cam groove 113 is adapted to move the cam follower 116 only in a range w
A pin 77a fixed at another end of the turnable lever 77 engages with a slot 130b provided at one end of a sub-rod 130. Guide slots 196 and 197 which are cut in the sub-rod 130 are fitted onto the guide shafts 194 and 195 respectively mounted on the chassis 1, and the sub-rod 130 is mounted movably for reciprocation alo
Next an explanation will be given of the brake controlling means 514.
A brake 184 at the take-up reel side and that 185 at the supply reel side are fitted rotatably onto the shafts 182 and 183 respectively as shown in FIGS. 2 and 8. A pin 184a fixed at one end of the brake 184 engages with a slot 187a provided at one end of a brake lever 187 which is fitted rotatably onto a shaft 186 mounted on the chassis 1, whereby the brake 184 at the take-up reel side is adapted to be actuated by the brake lever 187. A tension spring 189 is stretched between a pin 187b fixed at the other end of the brake lever 187 and a pin 188 fixed on the sub-rod 130, whereby the brake lever 187 is biased counter-clockwise by the tension spring 189 so that the brake 184 is biased clockwise as shown in FIG. 2. A tension spring 191 is stretched between a pin 185a fixed at one end of the brake 185 at the supply reel side and a pin 190 fixed on the sub-rod 130, whereby the brake 185 is biased counter-
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The intermittently rotating means 512 which transmits the rotational driving force of the motor 24 intermittently to both reel turntables 4 and 5 selectively, comprises a righthand stopper arm 126 and a lefthand stopper arm 127 fitted rotatably onto shafts 124 and 125 respectively mounted on the chassis 1. A tension spring 133 is stretched between a pin 128 mounted on the righthand stopper arm 126 and a pin 131 mounted on the sub-rod 130, the pin 128 abutting against a notch edge surface 130a provided on the sub-rod 130 to restrain the stopper arm 126 from turning counter-clockwise around the shaft 124. A tension spring 134 is stretched likewise between a pin 129 mounted on the lefthand stopper arm 127 and a pin 132 mounted on the sub-rod 130, the pin 129 abutting against a notch edge surface 118a provided on the main rod 118 and/or a notch edge surface 130d provided on the sub-rod 130 to restrain the stopper arm 127 from turning clockwise around the shaft 125.
When the conditions are changed from energizing the solenoid 81 as shown in FIG. 2 to de-energizing the solenoid 81 as shown in FIG. 16 at a rotary a
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When the solenoid 81 is energized and the two stopper arms 126 and 127 are positioned as shown in FIG. 2, the turnable idler gear 52 does not engage rotatably either with the idler gear 59 or 61 regardless of the turnable arm 50 being driven by the motor 24 which transmits its rotation to the turnable arm 50, and the turnable arm 50 turning clockwise or counter-clockwise around the shaft 39, since the shaft 51 mounted on the turnable arm 50 abuts against the edge surface 126a of the righthand stopper arm 126 or the edge of 127a of the lefthand stopper arm 127a. Hence, the two reel turntables 5 and 4 do not rotate. When the second rotatable disc 66 rotates clockwise to an angle of 110° as shown in FIG. 4A when the solenoid 81 is energized, the cam follower 116 is not moved and the main rod 118 is not moved either, whereby the both stopper arms 126 and 127 restrain the turnable arm 50 from turning as stated above. When the second rotatable disc 66 rotates clockwise more than an angle of 110° as shown in FIG. 4A in the condition of the solenoid 81 energized, the cam follower 116 is started to move rightwardly in FIG. 2,
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Next an explanation will be given of the pinch roller press-contact means 507 in FIGS. 10 and 11.
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A gear 135 in engagement with the second rotatable disc 66 driving the operating mode changing means 506 is fitted rotatably onto a shaft 136 mounted on the chassis 1 and engages with a toothed portion 139 integral with a driving member 138 which is fitted rotatably onto a shaft 137 mounted on the chassis 1. The driving member 138 is provided with a first peripheral cam 140, a cylindrical cam 141 and a second peripheral cam 142. The first peripheral cam 140 abuts against a first edge surface 144a of a relay lever 144 which is fitted rotatably onto a shaft 143 mounted on the chassis 1, so that the first peripheral cam 140 pushes the first edge surface 144a. The cylindrical cam 141 abuts against a projection 145a of a guide member 145 which is fitted onto the shaft 137, guided by the shaft 137 and capable of moving perpendicularly to the chassis 1, thereby moving the guide member 145 up and down. The second peripheral cam 142 abuts against a projection 146a of a pressure lever 146 which presses the pinch roller 22 to be in contact with the capstan 23 afte
The clockwise rotation of the second rotatable disc 66 is transmitted to the driving member 138 through the gear 135, so that the driving member 138 rotates clockwise. When the driving member 138 rotates to an angle of 277°, the first edge surface 144a of the relay lever 144 is pushed by the first peripheral cam 140 and the relay lever 144 rotates counter-clockwise around the shaft 143, at which time the second edge surface 144b of the relay lever 144 pushes the pin 155 and the guide post arm 154 rotates clockwise around the shaft 153. The tape guide post 15 fixed on the guide post arm 154 draws out the magnetic tape 9 to a predetermined position as shown in FIG. 17, so that the magnetic tape 9 forms a tape path as shown in dot-dash lines in FIG. 17, and the tape guide post 15 is locked by locking means (not shown). When the driving member 138 continues its rotation to an angle of 527° as shown in FIG. 5C, the guide member 145 abutting against the cylindrical cam 141, the pressure lever 146 and the pinch roller arm 148 move down integrally with each other perpendicularly to the tape path of the magnetic tape 9 along the shaft 143 guided by the cylindrical cam 141, and the pinch roller 22 also moves down perpendicularly to the tape path of the magnetic tape 9 as shown in FIG. 11
from the position where the tape guide post 15 is not hindered from drawing out the magnetic tape 9 as shown in FIG. 10, so as to be positioned inside of the loop of the tape path formed by the tape guide post 15 drawing out the magnetic tape 9 as shown in dot-dash lines in FIG. 17.
Furthermore when the driving member 138 continues its rotation and the projection 146a of the pressure lever 146 is pushed by the second peripheral cam 142, the pressure lever 146 and the pinch roller arm 148 turn clockwise integrally around the shaft 143, so that the pinch roller 22 abuts against the capstan 23 by the time when the rotary angle of the driving member 138 becomes 587°, whereby the pinch roller arm 148 is restrained from turning. After that, only the pressure lever 146 turns continuously and the hook 149 of the pressure lever 146 moves away from the hook 150 of the pinch roller arm 148 against the biasing force of the tension spring 151. When the driving member rotates to an angle of 587°, the pinch roller 22 is brought into press-contact with the capstan 23 at the predetermined strength. Even wh
Next an explanation will be given of the driving selecting means 504.
In FIGS. 12A, 12B and 6A, the second rotatable disc 66 which drives the operating mode changing means 506 and the tape loading means 508, and the third rotatable disc 67 which drives the cassette loading means 505 are both fitted rotatably onto the shaft 112 and in engagement with the retainer gear 85 and the transmission gear 88 respectively. On the outer peripheries of cylinders 66a and 67a of the second and third rotatable discs 66 and 67, notched grooves 160 and 161 are provided respectively, into which projection stoppers 158 and 159 are fit, the stoppers being provided at both ends of a detent arm 157 fitted rotatably onto a shaft 156 mounted on the chassis 1. When the projection stopper 158 of the detent arm 157 enters into the notched groove 160 of the second rotatable disc 66, the projection stopper 159 abuts against the outer periphery of cylinder 67a of the third rotatable disc 67. When the projection stopper 159 enters into the notched groove 161 of the third rotatable disc 67, the projection stopper 158 abuts against the outer periphery of cylinder 66a of the second rotatable disc 66. FIG. 12A shows the condition when the tape cassette 6 is not mounted on the apparatus, and FIG. 12B shows the condition when the tape cassette 6 in. When the tape cassette 6 is inserted into the apparatus when it is in the state shown in FIG. 12A,
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When the second rotatable disc 66 rotates through
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The driving gear 64 rotates clockwise when the motor 24 reversely rotates clockwise so that the rotational driving force of the motor 24 is used for changing from the operating mode changing means 506 or the tape loading means 508 to the cassette loading means 505. The second rotatable disc 66 rotating counter-clockwise and the cam follower 116 moving leftwardly, a projection stopper 115b provided on the left side of the turnable arm 115 abuts against a pin 66b fixed on the second rotatable disc 66 to stop the rotation of the second rotatable disc 66 as shown in FIG. 2, at which time the projection stopper 158 and the notched groove 160 are positioned opposite to each other. When the retainer gear 85 in engagement with the second rotatable disc 66 stops, the transmission gear 88 starts to rotate counter-clockwise, and the third rotatable disc 67 starts to rotate clockwise. Hence the projection stopper 159 moves out of the notched groove 161 by the moment of the counter-clockwise force around the shaft 156 generated by the rotational driving force of the third rotatable disc 67 through the notched groove 161, whereby the detent arm 157 starts to turn counter-clockwise, at which time the projection stopper 158 opposite to the notched groove 160 enters into the notched groove 160 to lock the second rotatable disc 66. Furthermore, when the driving gear 64 continues to rotate clockwise, the second rotatable disc 66 is kept in the locked condition by the projection stopper 158 and only the third rotatable disc 67 rotates continuously, so that only the cassette loading means 505 is driven.
Next an explanation will be given of the cassette loading means 505 in FIG. 13 which shows a side view of this mechanism.
Bosses 164 and 165 provided respectively on the right and left sides of a cassette holder 163 move slidably along guide grooves 168 and 169 provided respectively in a righthand side plate 166 and a
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Next an explanation will be given of the operations.
When the tape cassette 6 is inserted to the cassette holder 163 in FIGS. 2 and 13, the motor 24 rotates counter-clockwise with the solenoid 81 energized and the plunger 82 is retracted in the direction of the arrow A in FIG. 2, so that the turnable lever 77 turns counter-clockwise around the shaft 76 and the sub-rod 130 moves rightwardly in FIG. 2 against the tension force of the tension spring 199. With the movement of the sub-rod 130, the pins 187b and 185a move away from the notched edge surfaces 130e and 130f respectively, so that the brakes 184 and 185 are driven by the tension force of the tension springs 189 and 191 and the brake effect is applied to both reel turntables 5 and 4. The turnable idler gear 52 is also restrained from engaging rotatably with the idler gears 59 and 61. Simultaneously with the turnable arm 77 rotating counter-clockwise around the shaft 76, the first and second clutch plates 69 and 71 turn clockwise integrally with each other around the shaft 70, whereby the clutch gear 65 runs onto the upper surface 69a of the first clutch plate 69 and is changed from the condition as shown in FIG
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Further, when the motor 24 continues its rotation, the projection stopper 158 moves out of the notching groove 160 and the projection stopper 159 enters into the notched groove 161, so that the third rotatable disc 67 is locked and both the first rotatable disc 37 and the second rotatable disc 66 engageable with the retainer gear 85 start to rotate clockwise respectively. When the first rotatable disc 37 rotates to an engle of 20°, the motor 24 stops its rotation and the apparatus is put into the stopping mode.
When a fast-forward-winding button (not shown) is pushed with the apparatus in the stopping mode as stated above, the motor 24 starts to rotate counter-clockwise simultaneously and the solenoid 81 is de-energized. With the solenoid 81 de-energized, the sub-rod 130 is moved leftwardly as shown in FIG. 16 by the tension force of the tension spring 199, and the pins 187b and 185a are respectively pushed leftwardly in FIG. 16 by the notch edge surfaces 130e and 130f, so that the brakes 184 and 185 are moved away from the reel turntables 5 and 4 respectively, and the braking effect is released to allow both reel turntables to rotate.
When the pins 128 and 129 are also pushed leftwardly by the notch edge surfaces 130a and 130d of the sub-rod 130 respectively, the righthand stopper arm 126 turns clockwise around the shaft 124 and the lefthan
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Next, the motor stops its rotation and the solenoid 81 is energized, either when a stopping button is pushed in the fast-forward-winding mode or when a transparent tape (not shown) attached to the end of the magnetic tape 9 is optically detected to generate a termination detecting signal. As stated above, the sub-rod 130 is moved leftwardly in FIG. 16 instantaneously when the solenoid 81 is energized, and the notch edge surface 130a of the sub-rod 130 pushes the pin 128 to turn the righthand stopper arm 126 counter-clockwise. The edge surface 126a of the righthand stopper arm 126 urges the shaft 51 to turn the turnable arm 50 counter-clockwise in FIG. 16, so that the turnable idler gear 52 disengages from the idler gear 59 and the take-up reel turntable 5 stops its rotation. The brakes 184 and 185 are driven simultaneously by the tension force of the tension springs 189 and 191 respectively, and the brake effect is applied to the both reel turntables 5 and 4 instantaneously. The clutch gear 65 runs onto the upper face 69a from the lower face 69b of the first clutch plate 69 of which condition is changed from that in FIG. 6A to that in FIG. 6B, thereby allowing the clutch gear 65 to engage with the driving gear 64 again as shown in FIG. 6B. Hence the apparatus is placed in the stopping mode as shown in FIG. 14.
The explanation of the operation in the rewinding mode is omitted, because it is almost the same as that in the fast-forward-winding mode described above, except that the rotational direction of the motor 24 is the opposite and that the supply reel turntable 4 is rotatably driven.
Next, when a recording and/or reproducing button (not shown) is pushed when the apparatus is in a stopping mode, the motor 24 rotates counter-clockwise with the solenoid 81 still energized. The rotation of the motor 24 is transmitted through the clutch gear 65 in engagement with the driving gear 64 and the retainer gear 85 to the first and second rotatable discs 37 and 66, both of which rotate clockwise in FIG. 17. The rotary angle of the second rotatable disc 66 is the same as that of the first rotatable disc 37 as shown in FIGS. 5A and 5B, because the second rotatable disc 66 has the same diameter and number of teeth as the first rotatable disc 37. When the second rotatable disc 66 rotates through an angle of 110°, the cam follower 116 is moved rightwardly in FIG. 17 by the cam grove 113 so that the main rod 118 is moved straight leftwardly in FIG. 17. And the kick pins 192 and 193 are pushed leftwardly by the notch edge surfaces 118d and 118f respectively, so that the brakes 184 and 185 move away from the reel turntables 5 and 4 to allow the braking effect to be released. The condition of the braking effect being released is held until the rotary angle of the second rotatable disc 66 becomes 440
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When the first and second rotatable discs 37 and 66 rotate to an ang
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Next, when the stopping button is pushed in the recording and/or reproducing mode, the clutch gear 65 engages with the driving gear 64 and the solenoid 81 is energized as shown in FIG. 19 and the motor 24 rotates in the
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Furthermore, when an ejecting tape cassette button (not shown) is pushed, the projection stopper 159 moves out of the notched groove 161 of the third rotatable disc 67 and the projection stopper 158 enters into the notched groove 160 of the second rotatable disc 66, whereby the first and second rotatable discs 37 and 66 stop their rotations and the third rotatable disc 67 rotates clockwise in FIG. 2 so that the tape cassette 6 and the cassette holder 163 move from the position "B" to position "A" shown in FIG. 13 to eject the tape cassette 6 from the apparatus.
As seen from the above explanation, the present invention makes it possible to accomplish with only one motor the tape cassette loading operation, the tape loading operation, the operating mode changing operation and the magnetic tape transporting operation. For the above reason, the number of motors utilized in the apparatus is remarkably reduced thereby reducing the cost of the apparatus. Also, the apparatus has a low power consumption and light weight due to th
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The actuator comprises a plunger, so that its operation is quick in changing from the fast-forward-winding mode or rewinding mode to the stopping mode and so that it is possible to apply the brake effect instantaneously. Hence the braking action is so quick and ensured by detecting the end of the magnetic tape that the trouble of applying, exessive tension to the magnetic tape when its end is reached is eliminated.
Since the motor is a brushless motor with less torque variation and its spindle serves for the capstan, it minimizes the variation in the speed of the tape and also minimizes wow and flutter in the tape transport.
It must be also noticed that a
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