Mode changing system for a cassette tape recorder

Abstract

This invention relates to a mode changing system for a cassette tape recorder in which operating members such as a head base plate and a pinch roller are selectively moved to one of various modes such as stopping, fast forwarding, rewinding, pausing, cueing and playing. This system comprises control means to control the operating members so as to move them to a position corresponding to a selected one of the modes. The control means is actuated by a control electric motor. The system further comprises a mode selective switch group to select one of the modes, a reference signal generating circuit to generate a reference signal corresponding to the selected one of the modes in accordance with the selection of the modes by means of the mode selective switch group, a variable signal generating circuit to generate a variable signal which continuously varies with the rotation of the control electric motor and an operational circuit to receive both of the reference and variable signals so as to rotate the control electric motor for moving the operating members toward the position corresponding to the selected mode.

Description

BACKGROUND OF THE INVENTION

In the prior arts, various mode changing systems have been proposed in which and the rewinding mode, numerals II and II' the position of the fast forwarding mode, numerals III and III' the position of the cueing mode, numerals IV and IV' the position of the pausing mode, and numerals V and V' the position of the playing mode.

The mode changing system of the invention comprises a control electric motor 72 which rotates the cam 64 through a reduction gear, not shown, and drive means 73 which drives the control electric motor 72. The drive means 73 comprises a mode selective switch group 74, a reference signal generating circuit 76, a variable signal generating circuit 78 and an operational circuit or amplifier 80.

The mode selective switch group 74 comprises six switches S₁, S₂, S₃, S₄, S₅ and S₆ which serve to select the stopping, rewinding, fast forwarding, cueing, pausing and playing modes, respectively. The reference signal generating circuit 76 comprises six variable resistors VR₁, VR₂, VR₃, VR₄, VR₅ and VR₆ which are provided in parallel between source terminals +E and -E to generate reference voltages V₁ to V₆ corresponding to the respective modes at the respective variable terminals T₁ to T₆. The switches S₁ to S₆ at their one end are connected to the respective variable terminals T₁ to T₆ and at their other end connected to one of inputs 80a of the operational circuit 80. The variable signal generating circuit 78 comprises a variable resistor VR_c which is provided in parallel to the reference signal generating circuit 76 between the source terminals +E and -E and has a variable terminal T_c slidable with angular movement of the cam 64 by means of the control electric motor 72 to generate a variable voltage V_c corresponding to the angular position of the cam 64 at the variable terminal T_c. The variable terminal T_c is connected to the other input 80b of the operational circuit 80.

The operational circuit 80 serves to receive and comparatively operate the reference voltage selected from V₁ to V₆ and the variable voltage V_c at its inputs 80a and 80b. Thus, if the reference and variable voltage are equal to each other, then the operational circuit 80 generates a control output of O to maintain the control electric motor 72 in the stopped condition, if the reference voltage selected from V₁ to V₆ is higher than the variable voltage V_c, then the operational circuit 80 generates one control output to rotate the control electric motor 72 in a forward direction, and if the reference voltage selected from V₁ to V₆ is lower than the variable voltage V_c, then the operational circuit 80 generates another control output to rotate the control electric motor in a reverse direction. If the control electric motor 72 is rotated in the forward direction, the cam 64 is angularly moved in a counterclockwise direction in FIGS. 1 and 2, and the variable terminal T_c of the variable signal generating circuit 78 is slidably moved to make the variable voltage V_c higher. Reversely, if the control electric motor 72 is rotated in the reverse direction, the cam 64 is angularly moved in a clockwise direction in FIGS. 1 and 2, and the variable terminal T_c of the variable signal generating circuit 78 is slidably moved to make the variable voltage V_c lower. It will be noted that, since the cam groove 64a is sequentially set at the fast forwarding or rewinding, cueing, pausing and playing positions II, II', III, III', IV, IV' and V, V' in a clockwise direction, in relation to the reference position I, I' of stopping, the reference voltages V₁ to V₆ are so set that the reference voltage V₁ is minimum, the reference voltage V₆ is maximum and the reference voltages V₂ and V₃ are equal to each other.

In operation, supposing that the switch S₁ is closed, as shown, to select the stopping mode in which the control electric motor 72 stops. When an operator closes the switch S₆ to select the playing mode, the reference voltage V₆ at the input 80a of the operational circuit 80 is higher than the variable voltage V_c, and therefore, the operational circuit 80 causes the control electric motor 72 to be rotated in a forward direction. Thus, the cam 64 is angularly moved in a counterclockwise direction in FIGS. 1 and 2 while the variable terminal T_c is slidably moved so as to make the variable voltage V_c higher. In this manner, the level of the variable voltage V_c approaches that of the reference voltage V₆ until the former is equal to the latter. At that time, the operational circuit generates the control output of O which causes the control electric motor 72 to be stopped. Thus, the control pins 68 and 70 are located at the playing positions V and V' of the cam groove 64a and as a result, displaced from the solid line positions to the broken line positions indicated by numerals 68' and 70', respectively. Such displacement of the control pins 68 and 70 causes the control lever 38 to be angularly moved in a clockwise direction to move the head base plate 10 in a forward direction (indicated by the arrow A in FIG. 1), and the control lever 58 to be angularly moved in a counterclockwise direction to move the slidable arm 42 in a rightward direction (indicated by the arrow B in FIG. 1) so as to allow the L-shaped lever 32 to angularly move in a counterclockwise direction by means of the coil spring 56 to thereby urge the pinch roller 30 against the capstan 26. Thus, it will be noted that the cassette tape is supposed to be placed in the playing mode of the tape recorder.

In order to change the tape recorder from the playing mode to the stopping mode, the switch S₁ is closed and the components of the system is operated in a reverse manner to that of the above operation. Thus, the head base plate 10 is moved in a backward direction by the angular movement of the control lever 38 in a counterclockwise direction in FIG. 1 while the pinch roller 30 is moved far away from the capstan 26 by the angular movement of the control lever 58 in a clockwise direction in FIG. 1 and the resultant slidable movement of the slidable arm 42 in a leftward direction in FIG. 1.

It will be understood that, in case another mode of the tape recorder is selected by the corresponding switch of the mode selective switch group, the operating members such as the head base plate 10 and the pinch roller 30 will be moved in accordance with the selected mode in a manner similar to that of the selection of the modes. It will be also understood that a drive means for the reel wheels 22 and 22' and an amplifying circuit for recording or reproducing the tape will be operated in association with the selection of the modes in a conventional manner.

It should be noted that the operational circuit 80 controls the control electric motor 72 so that the level of the variable voltage V_c becomes equal to that of the variable voltage selected from V₁ to V₆. Thus, if the profile of the cam groove 64a around the playing position V or V' is so designed that the eccentricity of the cam groove 64a relative to the shaft 66 varies in a moderate manner, then the position of the head base plate 10 and the angular position of the L-shaped lever 32 can be minutely controlled by the fine adjustment of the variable terminal T₆ of the variable resistor VR₆. As a result, the condition of the heads 12 and 14 contacting with the tape and the force of urging the pinch roller 30 against the capstan 26 can be precisely controlled. In a similar manner, if the profile of the cam groove 64a around the cueing position III is designed in an identical form, then the condition of the heads 12 and 14 contacting with the tape can be precisely controlled.

Although, in the above embodiment, the components or operating members to be controlled or moved, such as the head base plate 10 and the pinch roller 30 are controlled by the single groove 64a in the common cam 64 engaged by the control pins 68 and 70, they may be separately controlled either by two grooves provided in the upper and lower faces of the common cam 64 or by respective grooves in separate cams. It will be understood that a brake device for the reel wheels may be also controlled in its position by the mode changing system. More particularly, the brake device may be so operated as to prevent the reel wheels from being driven in the stopping mode, and so controlled as to be released to allow the reel wheels to be driven in the fast forwarding and rewinding modes. Respective mode selective switches may control the traveling direction of the magnetic tape so that it travels in a forward or a reverse rewinding direction.

Further, although the stopping mode and the fast forwarding and rewinding modes in which the head base plate 10 and the pinch roller 30 are at the respective common positions are set at the different position I and II of the cam groove 64a, they may be set at the same position of the cam groove 64a. In the above embodiment, the reference signal and variable signal generating circuits 76 and 78 are adapted to generate voltages as the signals, nevertheless it will be understood that they may be adapted to generate frequency signals. In this case, the operational circuit 80 would compare the frequency signals from the signal generating circuits 76 and 78 to produce a control output therefrom.

While one preferred embodiment of the invention has been illustrated and described with reference to the accompanying drawing, it will be understood that it is by way of example, and that various changes and modifications may be made without departing from the spirit and scope of the invention, which is intended to be defined only by the appended claims .

Claims

1. A mode changing system for a cassette tape recorder wherein operating members such as a head base plate and a pinch roller are moved in accordance with operating modes of said cassette tape recorder comprising:

control means to control movement of the operating members to take a position corresponding to a selected mode of said cassette tape recorder;

a bidirectional control electric motor to actuate said control means;

a mode selective switch group to select one of said modes;

a reference signal generating circuit to generate a reference signal corresponding to the selected one of said modes in accordance with the selection of said modes by means of said mode selective switch group;

a variable signal generating circuit to generate a variable signal which continuously varies with the rotation of said control electric motor; and

an operational circuit to receive said reference signal at one of its inputs and said variable signal at the other input to compare said signals to generate a control output so as to rotate said control electric motor, said operational circuit being associated with said control means and said variable signal generating circuit so that said control output is generated for rotating said control electric motor when said operating members are at a position different from the position corresponding to the selected mode and for stopping said control electric motor when said operating members reach the position corresponding to the selected mode;

said control means including a rotary cam means having an advancing rotary range in which said operating member is advanced for engagement with a cassette tape and a retracting rotary range in which said operating member is retracted from the tape corresponding to a plurality of retracting modes, said retracting modes being placed together on said rotary cam means; and

said cam means being reversibly driven by said motor within a predetermined rotary angular range including said advancing and retracting rotary ranges corresponding to the selected operation of said mode selective switch group.

2. A mode changing system for a cassette tape recorder as set forth in claim 1, said reference signal generating circuit generating a reference voltage and said variable signal generating circuit generating a variable voltage.

3. A mode changing system for a cassette tape recorder as set forth in claim 2, said operational circuit generating such a control output that said control electric motor is rotated in a direction in which the level of said variable voltage varies toward the level of said reference voltage and that said control electric motor is stopped when the level of said variable voltage becomes equal to the level of said reference voltage.

4. A mode changing system for a cassette tape recorder as set forth in claim 1, wherein said control means comprises cam means to move said operating members in accordance with the rotation of said control electric motor.

5. A mode changing system for a cassette tape recorder as set forth in claim 4, said reference signal generating circuit generating a reference voltage and said variable signal generating circuit generating a variable voltage.

6. A mode changing system for a cassette tape recorder as set forth in claim 5, said operational circuit generating such a control output that said control electric motor is rotated in a direction in which the level of said variable voltage varies toward the lever of said reference voltage and that said control electric motor is stopped when the level of said variable voltage becomes equal to the level

of said reference voltage. 7. A control system for a cassette type tape recorder comprising a head base plate on which head means for a cassette type tape recorder is mounted, rotary cam means to move said head base plate corresponding to at least one advancing mode in which said head means engages a magnetic tape in a cassette and a plurality of retracting modes in which said head means is disengaged from said magnetic tape, a mode selective switch group operable so as to select one of said at least one advancing mode and said plurality of retracting modes, and a control motor driven in response to the selective operation of said mode selective switch group in a controlled manner to rotate said cam means to a predetermined rotary position in accordance with the selected mode, characterized in that;

said cam means has an advancing rotary range in which said head base plate is advanced corresponding to said advancing mode and has a retracting rotary range in which said head base plate is retracted corresponding to said retracting modes, said retracting modes being placed together; said control motor being reversible; said cam means being reversibly controlled within a predetermined rotary angular range comprising said advancing and retracting rotary range relative to reversible rotation of said control motor corresponding to the selected operation of said mode selective switch group;

a reference signal generating circuit to generate a reference signal corresponding to the selected one of said modes in accordance with the selection of said modes by means of said mode selective switch group;

a variable signal generating circuit to generate a variable signal which continuously varies with the rotation of said control electric motor; and

an operational circuit to receive said reference signal at one of its inputs and said variable signal at the other input to compare said signals to generate a control output so as to rotate said control electric motor, said operational circuit being associated with said control means and said variable signal generating circuit so that said control output is generated for rotating said control electric motor when said operating members are at a position different from the position corresponding to the selected mode and for stopping said control electric motor when said operating members reach the position corresponding to the selected mode.