JPS5923018B2 - Tape recorder drive mechanism - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a drive mechanism for a tape recorder, particularly a small cassette tape recorder such as a car stereo.

When the tape wound on a cassette is left unattended, the reel hub rotates due to vibrations, etc., and the tape sometimes becomes loose.

If a loose tape is loaded into a tape recorder and immediately played back, the tape will not only wrap around the capstan, making playback impossible, but also sometimes causing damage to the tape. Therefore, before playback, it is necessary to rotate the reel stand to remove slack in the tape.

Conventionally, this type of device rotates only one side of the reel stand, electrically detects when the slack in the tape is removed and the other reel stand begins to rotate, and when this rotation is detected, it enters the playback state. Therefore, it takes time to remove tape slack, and if a detection device that detects the rotation of the reel stand is also applied to a tape end detection device, it is necessary to install a special circuit to detect the start of rotation of the reel stand. Ta. This invention was made in view of the above points, and its first object is to provide a simple device that can quickly remove tape slack by rotating the reel stands relative to each other in the tape winding direction. To provide a drive mechanism for a tape recorder that can detect the end of the tape and remove tape slack even during operation.

A second object of the present invention is to provide a drive mechanism for a tape recorder in which an auto-stop mechanism detects that tape slack has been removed and stops the rotation of the reel stand.

Next, one embodiment of the structure will be described with reference to the drawings.

1 is a chassis, 2 is a motor attached to the chassis 1, 3 and 4 are first and second flywheels, and the lower ends of rotating shafts 3a and 4a are bearings on a back plate 5 attached to the back of the chassis 1 Further, the upper parts of the rotating shafts 3a and 4a are supported by resin bearing plates 6 and T attached to the chassis 1.

Note that the portions of the rotating shafts 3a, 4a that protrude upward from the bearing plates 6, T serve as a capstan, and hence the rotating shafts 3a34a will be referred to as capstans hereinafter.
Furthermore, guide gauges 6a and Ta, which are fitted into guide holes of the cassette, are integrally molded on the bearing plates 6 and T, respectively. 8
is a pulley pivotally supported on a base plate for equipping a tape stop detection unit to be described later, and this pulley 8 is fitted to the above-mentioned first and second flywheels 3 and 4 and the rotating shaft 2a of the motor 2. A belt 9 is wound around the pulley 2b (see FIG. 2).

Therefore, when the motor 2 rotates, the first and second flywheels 3 and 4 and the pulley 8 are rotated. 1st and 2nd above
Gears 3b, 4b are formed on the flywheels 3, 4, respectively, and control levers 10, 1 are connected to the gears 3b, 4b, respectively.
The connecting gears 10a and 11a provided in 1 are meshed with each other,
Further, the connecting gears 10a, 11a are meshed with gears 12a, 13a of the first and second reel stands 12, 13, respectively.

Therefore, when the first and second flywheels 3 and 4 rotate,
The first and second reel stands 12 and 13 each rotate in the direction of winding the tape. The levers 10, 11 have a substantially U-shape, and one end 10b, 11b is a pin 1 implanted in the chassis 1.
The other end control portions 10c and 11c, which are pivotally supported by a and 1b and tensioned with a spring 11e, correspond to a head 41a of a selection arm 41, which will be described later. And the control section 10c, 1
The connecting gears 10a and 11a are pivotally supported near 1c. Therefore, the control levers 10, 11 are connected to the pins 1a, 1b.
When rotated about the fulcrum, the connecting gears 10a and 11a move along the outer circumferences of the gears 12a and 13a of the first and second reel stands 12 and 13, and the first and second flywheels 3 and 4
The gears 3b and 4b engage and disengage. Note 1
0d and 11d, release levers 18 and 19, which will be described later, are connected to pin 1.
an engagement for moving the control levers 10, 11 by being engaged with them when rotated about a, 1b as fulcrums, thereby releasing the engagement between the connecting gears 10a, 11a and the gears 3b, 4b. It's a piece. Reference numerals 14 and 15 designate release plungers attached to the back surface of the chassis 1, and pins 14a and 15a implanted in the suction rods of the release plungers 14 and 15 protrude from the upper surface through elongated holes in the chassis 1.

Reference numerals 16 and 17 designate operating levers with the pins 14'A and 15a pivotally supported at one end, and springs 18 and 17 between them and the chassis 1.
19 are installed.

Reference numerals 20 and 21 are release levers whose one end is pivotally supported by the other end of the operating levers 16 and 17, and whose approximate center is the chassis 1 described above.
It is pivotally supported by pins 1a and 1b.

Reference numeral 22 designates a lock plate which is pivotally supported by a pin 1c implanted in the chassis 1, and has an upright piece 22a formed corresponding to the other end abutting piece of the release levers 20, 21, and a head stand 24 which will be described later. A locking piece 22b is formed to be engaged with a roller 24c attached to the roller 24c.

Note that this lock plate 22 is always given a clockwise rotational force by a spring 23. 24 is sashimi 1
A guide groove 24a is drilled in which the pin 1d installed in the chassis 1 is guided, and a pin 24b is installed in the chassis 1 to be guided in the guide groove, thereby making the head stand movable in parallel. A playback head 25 is attached.

If the head stand 24 is a table recorder having a recording function, the playback head 25 is used as a recording head, or a separate recording head is provided and an erasing head is attached. Further, a roller 24c is provided at the tip of the head stand 24, and is engaged with the lock piece 22b of the lock plate 22 when the head stand 24 moves forward. 26, 27
is a pinch roller unit, and the support frames 26a and 27a are
is pivotally supported by pins 1e and 1f implanted in the chassis 1,
Pinch rollers 26 are provided on the support frames 26a and 27a, respectively.
b, 27b are rotatably mounted, and rollers 26c, 27c extending downward are also mounted, and the pin 1
Wrapped springs 26d and 27d are provided which are wound around e and 1f and have both ends engaged with support frames 26a and 27&.

Note that one end of these coiled springs 26d and 27d is attached to the head stand 24.
It corresponds to the upright pieces 24d and 24e formed at both ends of the . Further, the rollers 26c and 27c face notches 24f and 24g formed in the head stand 24. Reference numeral 28 denotes a selection plunger attached to the chassis 1, which serves to select the forward movement of the head stand and the running direction of the tape.

Reference numeral 29 designates a lever for advancing the head stand which is pivotally supported by a pin 1g installed on the back surface of the chassis 1, and is formed in a substantially dogleg shape. A pin 29a is implanted at the other end.

30P A control plate having an engaging pawl 30a pivotally supported by the pin 29a, and a clockwise rotational force is always applied by a coil spring 31 provided on the pin 29a. The upright piece 29c formed in
is in contact with.

A spring 32 is stretched between the other end of the forward lever 29 and the chassis 1, and applies a counterclockwise rotational force to the lever 29.

When the head stand 24 is retracted and the forward lever 29 is rotated counterclockwise, the control plate 30 has an engaging pawl 30a engaged with a pin 28a implanted in the selection plunger 28. Furthermore, when the head stand 24 is moving forward, it is retracted to a position away from the locus of movement of the pin 28a. Reference numeral 33 designates a rotating lever that is pivotally supported by a pin 1h installed in the chassis 1, and one end of which is connected to the selection plunger 2.
It is pivotally supported by the No. 8 pin 28a.

A rotating arm 34 is pivotally supported by a pin 11 implanted in the chassis 1, and has a pin 34a implanted at one end and extends to the back surface of the chassis 1.

Note that when the head stand 24 is retracted, the rotating arm 34 comes into contact with the upright pieces 24d and 24f provided on the head stand 24 and is in a horizontal state. Reference numeral 35 designates a swinging lever in which a pin 34a of the swinging arm 34 is passed through an elongated hole 35a, and a pin 35b implanted at one end is pivotally supported by the other end of the swinging lever 33.

Further, the other end of this swing lever 35 has two engaging claws 35c.
, 35d are formed. Reference numeral 36 designates a control arm that is pivotally supported by a pin 1j implanted in the chassis 1, one end of a spring wire 37 is wound around the implanted pin 36a, and approximately the middle portion passes through a hole in the upright piece 36b. The distal end thereof is inserted between two protrusions 34b formed on the rotating arm 34.

Engagement rods 36c and 36d extending to the rear surface of the chassis 1 are implanted in the control arm 36, and when the head stand 24 is moving forward, the engagement claws 35c and 36d of the swing lever 35 are
5d are engaged alternately. 38 is a torsion spring for selectively fixing the rotation of the control arm 36 in two positions.

A spring 39 is stretched between the swing lever 34 and the chassis 1 and pulls the lever 34 to the left.

40 is a pin (not shown) planted on the back side of chassis 1
is inserted into the elongated hole 40a and moves in parallel, and an engagement rod 36d provided on the control arm 36 is engaged with a groove 40b at one end of the slide lever.

This slide lever 40 has a stepped portion 40 that comes into contact with the rollers 26c and 27c of the pinch roller units 26 and 27 to control contact and separation with the capstans 3a and 4a.
c, 40d, and a roller 41b of the selection arm 41, which will be described later.
, 41c to control rotation of the selection arm 41 are formed. Reference numeral 41 denotes a substantially cross-shaped selection arm whose center is pivotally supported by the pin 24b of the head stand 24 described above, and whose head 41a is the control section 10c, 11c facing the control levers 10, 11 described above. A roller 41b is located between the rollers 41b and 41b at both ends extending in the lateral direction.
41c is provided.

Reference numeral 42 designates a tape stop detection unit mounting plate, and on its lower surface are the above-mentioned pulley 8, a large gear 43 that meshes with the gear 8a formed on the pulley 8, and a small gear 43 formed integrally with the large gear 43. A cam plate 44 having a gear 44a that meshes with the gear 43a provided on its outer periphery is pivotally supported.

A cam groove 44b is formed on the upper surface of this cam plate 44, which is the surface facing the mounting plate 42, and a cam base 44c is formed in the center.
is formed. A switch 45 for energizing the selection plunger 28 is mounted on the lower surface of the mounting plate 42, and a switch control lever 46 for controlling opening and closing of the switch 45 is pivotally supported. One end of the lever 46 faces the switch 45, and the other end is pivotally supported by one end of a pin support lever 47. An engaging pin 47a facing the cam groove 44b of the cam plate 44 is formed at the other end of the pin support lever 47, and its upper end passes through the guide groove 42a of the mounting plate 42. A detection arm 48 has a guide rod 48a slidably inserted into the guide groove 42a, and a guide pin 48b is pivotally supported in the small hole 42b of the mounting plate 42.

Further, a forked engagement piece 48c is formed on the detection arm 48, and an engagement pin 47a of the support lever 47 is engaged with this engagement piece 48c. Reference numeral 49 is a detection lever having a hole 49a drilled in the center and pivotally supported by a pin 48d formed on the upper surface of the guide rod 48a of the detection arm 48, and long holes 49b and 49c are bored at both ends thereof.

The elongated holes 49b and 49c have the above-mentioned first and second holes.
Slip plate 12 provided on the bottom surface of reel stands 12, 13
The protrusions b and 13b are engaged. This slip plate 1
2b, 13b are shaft portions 13c (first
The same applies to the reel stand 12 side, so here we will use the second reel stand 1.
Only the third side will be explained with reference to FIG. 7), and is pressed toward the plate portion 13f by the spring 13d via the felt 13e. Therefore, when no load is applied to the slip plate 13b, the slip plate 13b also rotates together with the reel stand 13;
When a load is applied to 3b, it slips and stops rotating. Note that the protrusions on the slip plates 12b and 13b are attached to the mounting plate 42.
It faces into the holes 42c and 42d. Reference numeral 50 denotes a track changeover switch whose contacts are changed as the control arm 36 rotates to change over the reproduction coil of the head 25, and 51 is a motor whose contacts are changed by the lever 29 for advancing the headstand when the headstand 24 moves forward. 2 is a switch that causes constant speed rotation, and vice versa when switched to high speed rotation.

The structure has been described above, and the operation will now be described.

When the force set is not loaded, the head stand 24 is retracted, so the selection arm 41 is also retracted, and the control parts 10c and 11c of the control levers 10 and 11 are
It is not displaced by a.

Therefore, the connecting gear 10a is the gear 3 of the first flywheel 3.
a and the gear 12a of the first reel stand 12, and the connecting gear 11a connects the gear 4a of the second flywheel 4 and the second
It is connected to the gear 13a of the reel stand 13. When a force set (not shown) is loaded in this state, the motor 2 is energized by a power switch (not shown).

At this point, since the head stand 24 is retracted, the motor 2 is rotated at high speed in the direction of the arrow in FIG. 2 at the contact point of the switch 51. Therefore, the first and second reel stands 12, 13
are both rotated in the tape winding direction, and if there is slack in the tape, this slack is removed. Also, the reel stand 12,1
3 is rotated, the slip plates 12b and 13b are also rotated in the same direction, so that the detection lever 49 moves upward as shown in FIG. When the guide rod 48a of the detection arm 48 moves within the guide groove 42a as the detection lever 49 moves, the detection arm 48 is rotated about the guide pin 48b, so that the engagement piece 48c is moved to the right. Displace.
Since the engaging pin 47a of the support lever 47 is engaged with the displaced engaging piece 48c, the cam groove 4 of the cam plate 44
The lower end of the engagement pin 47a facing the cam groove 4b
It is pressed against the inner circumferential wall of 4b. Therefore, even if the cam plate 44 is rotated by the pulley 8, the engagement pin 47a remains on the cam base 4.
The engagement pin 4 does not come into contact with the engagement portion 44d of 4c.
7a maintains a state along the inner circumferential wall. When the tape slack is removed, the reel shaft portions 12c of the reel stands 12, 13,
Since the rotation of 13c is stopped by the friction between reel stands 12 and 13, the rotational force of slip plates 12b and 13b is eliminated.

Note that the reel stands 12 and 13 are in a slip state with the reel shafts 12c and 13c, so they continue to rotate. Ru. On the other hand, since the cam plate 44 is constantly rotated by the pulley 8, the engagement pin 47a is moved toward the center by the inner circumferential wall of the cam groove 44b and maintained in that state. Since the engaging portions 44.d of the cam base 44c are located on the locus of the moved engaging pin 47a, the engaging pin 47a is pushed by the engaging portion 44d. Therefore, the switch control lever 46 is rotated to close the switch 45. Since this switch 45 is connected to the selection plunger 28, the plunger 28 is energized. When the plunger 28 is energized and the suction rod is pulled, the pin 28a is engaged with the engaging pawl 30a of the control plate 30, so the control plate 30 is pulled and the lever 29 for advancing the headrest is moved clockwise. is rotated.

Since the guide pin 24b of the head stand 24 is engaged with the forked portion 29b of this lever 29, the head stand 24 moves forward, and the roller 24c provided at the tip engages with the lock piece 22b of the lock plate 22. be done. Therefore, even after the selection plunger 28 is de-energized and the suction rod is restored,
The head stand 24 is fixed in the forward position. Note that when the head platform advancement lever 29 is rotated, the control plate 30 is rotated toward the upright piece 29c by the coiled spring 31, so the engaging claw 30a leaves the trajectory of the pin 28a of the plunger 28. . Therefore, when the head stand 24 is moving forward, even if the plunger 28 is energized again, the pin 28a and the engaging pawl 30a are not engaged with each other. On the other hand, when the head stand 24 moves forward, the rollers 2 of the pinch roller units 26 and 27
6c, 27c are disengaged from the notches 24f, 24g of the head stand 24, and the coiled spring 26d is released from the middle of their forward movement.
, 27d are pushed by the upright pieces 24d, 24e, thereby causing the respective pinch roller units 26, 27 to
is rotated by the spring force toward the capstans 3a and 4a.

Assuming that the slide lever 40 is moving to the right as shown in FIGS. 5 and 10, the roller 26c of the pinch roller unit 26 is moved to the stepped portion 40c of the slide lever 40, and the roller 41b of the selection arm 41 is moved to the stepped portion 40e. Since they abut on each other, rotation of the pinch roller unit 26 is stopped midway, and the pinch roller 26b does not abut on the capstan 3a.

Further, the selection arm 41 is rotated counterclockwise to
a contacts the control portion 10c of the control lever 10 and moves it, so that the connection gear 10a and the gear 3 of the first flywheel 3
Remove the mesh with b. On the other hand, since the roller 27c on the side of the pinch roller unit 27 is located away from the stepped portion 40d of the slide lever 40, rotation of the pinch roller unit 27 is not prevented, and therefore the pinch roller 27b is pressed against the capstan 4a. .

Further, since the head 41a of the selection arm 41 and the control part 11c of the control lever 11 do not come into contact with each other, the gear 4b of the second flywheel 4 and the second reel stand 13 are connected to each other by the connecting gear 11a.
continues to be connected to gear 13a. Further, since the head table advancement lever 29 switches the switch 51, the motor 2 rotates at a constant speed. As a result, the head 25 comes into contact with the tape, and the second reel stand 13 starts rotating in the tape winding direction, and the tape is pinched between the capstan 4a and the pinch roller 27b, so that reproduction begins.

Next, a case will be described in which the playback progresses and the tape reaches its end.

If the tape is now wound on the second reel stand 13 side,
The slip plate 13b of the second reel stand 13 applies a clockwise rotational force to the detection lever 49, and the slip plate 12b of the first reel stand 12 applies a clockwise rotational force as well. .

Therefore, the detection arm 48 is rotated clockwise, and the engagement pin 47a of the pin support lever 47 is engaged with the cam groove 44b of the cam plate 44.
It maintains a state along the inner circumferential wall of the cam base 44c and is not engaged with the engaging portion 44d of the cam base 44c. Now, the running of the tape has stopped and the reel shafts 1 of the first and second reel stands 12 and 13
2c, 13c stop, the reel shaft portions 12c, 13 of the reel stands 12, 13 are removed after removing the tape slack described above.
The switch 45 is closed and the selection plunger 28 is energized in the same way as when the 0 stops.

When the plunger 28 is energized and the suction rod is pulled, the rotating lever 33 is rotated clockwise. Note that since the head stand 24 is moving forward, the control plate 30 is not connected to the engaging claw 30a.
is withdrawn from the locus of the pin 28a, so the head stand advancement lever 29 is not rotated. Here, the slide lever 40 is moving to the right, and the groove 40b of this
Since the control arm 36 with which the engagement rod 36d is engaged is rotated counterclockwise, the rotation arm 34 is rotated clockwise via the spring wire 37. The swing lever 35, in which the pin 34a of the swing arm 34 is inserted into the elongated hole 35a, is rotated clockwise, and the engagement claw 35d is engaged with the engagement rod 36d of the control arm 36. Therefore, when the pivot lever 33 is pivoted clockwise and the swing lever 35 is pulled, the control arm 36 is pivoted clockwise. As a result, the slide lever 40 moves to the left as shown in FIG.
d rides on the stepped portion 40d, and the roller 41c of the selection arm 41 rides on the stepped portion 40f. Therefore, the pinch roller 27b is separated from the capstan 4a, and the control part 11c of the control lever 11 is pushed by the head 41a as the selection arm 41 is rotated clockwise, and the connecting gear 11a is moved to the second position. away from gear 4b of flywheel 4,
The rotational force applied to the second reel stand 13 is eliminated. On the other hand, since the roller 26d of the pinch roller unit 26 comes off the step 40c, the pinch roller 26b is pressed against the capstan 3a, and the head 41a of the selection arm 41 is pressed against the control lever 1.
0, the connecting gear 10a connects the gear 3b of the first flywheel 3 and the gear 12a of the first reel stand 12. As a result, the tape starts running in the opposite direction, and the rotation of the control arm 36 causes the switch 5 to
The 0 contact is switched to switch the channel of the head 25, thus reproducing the track in the opposite direction. By the way, in the above state, the control arm 36 is rotated clockwise,
Since the rotation arm 34 is rotated counterclockwise by the spring wire 37, the swing lever 35 is rotated counterclockwise, and the engagement claw 35c engages with the engagement rod 36c of the control arm 36. is maintained in a state where it can be assembled. Therefore, playback ends again,
When the tape running stop is detected by the same operation as described above and the selection plunger 28 is energized, the swing lever 35
rotates the control arm 36 counterclockwise and pulls the slide lever 40 to the right, resulting in the above-mentioned initial state and starting reproduction in the original direction. If you want to change the playback channel during playback, close the switch using the replay button (not shown) and press the selection plunger 2.
By energizing 8, it becomes possible to reproduce in the reverse direction by the same operation as that after detecting the end of the tape described above.

Next, a case will be described in which rewinding is performed during playback shown in FIG. 10, that is, during playback when the tape is being wound rightward.

When you press the rewind button (not shown) and close the switch,
The release plunger 15 is energized and its suction rod is pulled.

As a result, the operating lever 17 is pulled against the spring force of the spring 19, and the release lever 21 is rotated counterclockwise.
The tip of the upright piece 22a of the lock plate 22
It rotates counterclockwise against the spring force of 3. Therefore, the lock piece 22b and the roller 24c of the head stand 24 are unlocked, and the spring 3 is released via the head stand advancement lever 29.
Move back with spring force of 2. Further, since the release lever 21 is rotated counterclockwise, the engagement piece 11d of the control lever 11 is engaged with the release lever 21 and rotated, and the connecting gear 11a is moved to the second
Away from the gear 4b of the flywheel 4, the second reel stand 1
3 is in a free state. On the other hand, the control section 10c of the control lever 10 is no longer restricted by the head 41a of the selection arm 41, which retreats as the head stand 24 retreats, so it returns to its original position by the spring force of the spring 11e and connects the connecting gear 10a. connects the gear 3b of the first flywheel 3 and the gear 12a of the first reel stand 12. Further, the head stand 24 moves backward, the head stand advance lever 29 switches the switch 51, and the motor 2 rotates at high speed. Therefore, the first reel stand 12 rotates at high speed and winds up the tape. When the rewinding of the tape is completed and the end of the tape is reached, the switch 45 is closed by an operation similar to the operation after detecting the end of the tape described above, and the selection plunger 28 is energized, and the release plunger 15 is energized. is interrupted, and the head stand 24 advances again to perform playback, but at this time, playback is performed in the direction that was being performed before rewinding.

This allows the rotating arm 34 to move when the head stand 24 is retracted.
The upright pieces 24d and 24f keep the swinging lever 3 in a horizontal state.
5 is in a horizontal state so that the engaging claws 35c, 35d do not engage with any of the engaging rods 36c, 36d of the control arm 36. In addition, when returning to playback during rewinding, the Q current to the release plunger 15 is cut off by operating a replay button (not shown) or the like.

As a result, the operating lever 17 is returned by the spring 19 and the release lever 21 is returned, so that the control lever 11
returns to its original position. Therefore, the connecting gear 11a is the gear 4b of the second flywheel 4 and the gear 13a of the second reel stand 13.
Since the second reel stand 13 rotates in the opposite direction to the first reel stand 12, if there is slack in the tape,
Remove slack. After the slack is removed, the head stand 24 is moved by the same operation as when loading the tape described above.
advances, and playback is performed in the playback direction before rewinding. Next, a case will be described in which fast forwarding is performed during playback, that is, during playback when the tape is being wound in the right direction.

When you press the fast forward button (not shown) and close the switch,
After the release plunger 14 is energized and the entire tape is wound in the same manner as when rewinding is performed during playback, the first and second reel stands 12 and 13 are moved in the tape winding direction. The camera rotates to , and sigma rotation starts in the fast forward direction.

However, since the tape is all wound in the fast forward direction, actual playback is not performed and the tape is stopped. Thereupon, the tape end detection operation is performed, the switch 45 is closed, and the selection plunger 28 is energized, so that the playback progresses and the tape end is reached and playback is performed in the opposite direction. Reproduction is started in the reverse direction. Next, to explain the force setting eject, when you operate the eject lever (not shown),
First, the lock plate 22 is rotated counterclockwise by the ejector lever. After releasing the lock with the head stand 24, the power set is released and the power supply is cut off, ending the entire operation. In the above embodiment, the power switch is turned on when the cassette is loaded, but the power switch may be provided separately and turned on manually.

In addition, in order to remove tape slack, the first and second reel stands 1
2 and 13 in the winding direction, detecting that the tape slack has been removed and the rotation of the reel shaft portions 12c and 13c has stopped, the selection plunger 28 is energized to perform playback. This may be done by energizing the selection flange 28 for a certain period of time after loading the tape, or by detecting the tension of the tape.

Further, in the above embodiment, the gears 3b, 4 of the first and second flywheels 3, 4 are connected by the connecting gears 10a, 11a from the beginning.
b and the gears 12a, 13a of the first and second reel stands are shown connected, but it is also possible to connect them after the force set is loaded.

In the above embodiment, when the reel stands 12 and 13 are rotated in the tape winding direction and the slack of the tape is removed,
That is, the reel shaft parts 12c, 13c rotated by the reel stands 12, 13 when the tape is in a tensioned state are made of a friction material such as felt provided between the reel stands 12, 13 and the reel shaft parts 12e, 13c. In this case, even if all the tape was wound on one reel stand side, the wound tape should not be wound on the other reel stand side (this Unless a friction material is provided (the state with the highest torque difference), it is not possible to detect tape stop and proceed to the next operation.

If a large friction is applied between the tape and the tape, an excessive force will be applied to the tape at the end of the tape, which may cause the tape to be cut. Therefore, an abnormally large amount of friction is applied between the reel stand and the reel shaft, and only when the table slack is removed, when each reel stand tries to rotate from the winding rotation direction to the supply rotation direction, the reel shaft of that reel stand It is conceivable that a stopper engages with the portion and prevents it from rotating. Specific examples thereof will be explained below with reference to FIGS. 13 to 15.

Numerals 52 and 53 are approximately L-shaped ratchet plates whose approximately centers 52a and 53a are pivoted to the chassis 1, one of which is located on the lower surface of the plate portions 12f and 13f of the reel stands 12 and 13, and on the upper surface thereof. Ratchets 52 correspond to the engagement protrusions 12g and 13g formed on the lower surfaces of the plate parts 12f and 13f.
b, 53b are formed.

Note that the ratchets 52b and 53b engage the engaging protrusions 12g and 12g when the reel stands 12 and 13 rotate in the tape winding direction.
13g but is not engaged, and the reel stand 12,1
3 rotates in the tape supply direction, the engagement protrusion 12g
, 13g are engaged with the ratchets 52b, 53b, and are shaped to prevent the plate portions 12f, 13f of the reel stands 12, 13 from rotating. Also, the ratchet plates 52, 53
Engagement pins 52c and 53c are formed at the other end, and a spring 54 is tensioned to apply a force that causes the engagement pins 52c and 53c to move outward from each other. The rotational force of the ratchet plates 52 and 53 applied by the spring 54 is applied to the stoppers 10e and 10e formed on the control levers 10 and 11, respectively.
11e. Further, the engaging pins 52c, 53c are inserted into the head stand 24 corresponding to the above-mentioned engaging pins 52c, 53c, and the ratchet plates 52, 53 are rotated in the latter half of the forward movement of the head stand 24, so that the ratchets 52b, 53b are rotated. Guide grooves 24h and 241 are formed for retracting the engagement protrusions 12g and 13g from their loci. Next, to explain the operation, in FIG. 13, the head stand 24 is retracted, When the stands 12 and 13 are rotated in the tape winding direction, the ratchet 5
Since the ratchets 52b, 53b are located on the rotation locus of the engaging projections 12g, 13g, the ratchets 52b, 53b and the engaging projections 12g, 13g come into contact with each other. The ratchets 52b and 53b are rotated against the spring force of the engaging protrusions 12g and 13.
Move from the trajectory of g.

Therefore, the plate portions 12f, 13f of the reel stands 12, 13 continue to rotate (see the side of the reel stand 13 in FIG. 3). Next, the slack in the tape is removed, and if, for example, the amount of winding on the reel stand 13 side is small, the tape moves to the reel stand 13 side, so the reel stand 12 side becomes the supply side.

Therefore, since the engaging protrusion 12g comes into contact with the ratchet 52b and is engaged due to its shape, a force is applied to rotate the ratchet plate 52 clockwise. As a result, the rotation of the plate portion 12f of the reel stand 12 is prevented (reel stand 1 in FIG. 13).
(See side 2). As a result, the above-mentioned tape end detection device is activated and a transition is made to the playback state. When the reproducing state is reached, first the head stand 24 moves forward as shown in FIG.
Since the tips of h and 241 form an arc that matches the rotation locus of the ratchet plates 52 and 53, the ratchet plates 52 and 53 are rotated against the spring force of the spring 54, respectively, in the latter half of the forward movement of the head stand 24. . Therefore, the ratchet 52b,
53b is retracted from the locus of the engaging protrusions 12g and 13g, so that the engagement between the two is eliminated. Of course, during this reproduction, one of the control levers 10 and 11 (the control lever 11 side in the figure) is rotated by the selection arm 41 described above, but the rotation is obstructed by the ratchet plate 53. Nothing happens. Next, in order to perform fast forwarding or rewinding in FIG. 13, it is necessary to prevent engagement between one of the ratchets and the engaging protrusion.

For example, when the tape is wound to the right, when the control lever 11 is rotated by the selection arm 41, the stopper piece 11e moves back as shown in FIG. Since the ratchet plate 53 is released, the ratchet plate 53
is rotated by the spring force of the spring 54, so that the ratchet 53b is retracted from the trajectory of the engagement protrusion 13g. As a result, the rotation of the reel stand 13 in the supply direction is not inhibited and the tape is wound. Further, since the winding in the opposite direction is similar, a description thereof will be omitted. Furthermore, in the embodiment, a mode is shown in which the tape shifts to the playback state after removing tape slack. , 13, and then by operating other operating levers (playback, fast forward, rewind), the connecting gears 10a, 11a are selectively moved.
As described above, in this invention, the first reel stand and the second reel stand are rotated relative to each other in the tape winding direction. By doing so, if there is any slack in the tape, it can be removed quickly, and when the slack in the tape is removed and the tape stops running, the auto-stop mechanism detects and stops the rotation of the reel stand, allowing playback. , the tape is in a standby state for the next operation such as fast forwarding or rewinding, and even if tape slack occurs during the operation, that is, after fast forwarding or rewinding, it is possible to remove the slack, and therefore the tape can be moved to playback. In addition to being able to prevent damage to the tape even when the tape is running, it also detects that the tape has stopped running, so it has the advantage of being able to detect the end of the tape.

[Brief explanation of the drawing]

Fig. 1 is a plan view of the entire tape recorder, Fig. 2 is a perspective plan view as seen from the chassis, Fig. 3 is an exploded perspective view, Fig. 4 is a plan view of the head stand drive part showing the playing state, Fig. 5, 6
Figure 7 is a plan view of the part that changes the running direction of the tape in the forward moving state, Figure 7 is a central vertical sectional view of the reel stand, Figures 8 and 9 are perspective plan views of the tape end detection part, and Figure 10 is Fig. 11 is a plan view of the leftward playback state, Fig. 12 is a plan view of the leftward fast forwarding state, and Figs. 13 to 15 are the plan views of the tape movement after removing tape slack. FIG. 1. ．． ．． ．． ．． ．． Chassis, 2...Motor, 3,
4...First and second flywheels 10, 11
...Down lever 12,13...1st,
Second reel stand, 14, 15... Release plunger, 16, 17... Operating lever, 20, 21.
...Release lever, 22...Lock plate, 24...Head stand, 26, 27...
・Pinch roller unit, 28...Plunger for selection, 29...Lever for advancing head platform, 30
...Control plate, 33... Rotating lever, 34... Rotating arm 35... Rocking lever 36... Control Arm, 40...
・Slide lever, 41... Go to selection 42.
...Unit mounting plate, 43...Large gear,
44...Cam plate, 45, 50, 51...
・Switch, 46...Lever for switch control,
47...Pin support lever, 48...Detection arm, 49...Detection lever, 52, 53...
... Rachietsu board.

Claims (1)

[Claims] 1. When a cassette is loaded and the power is turned on, there is a drive means for rotating the first and second reel stands in the tape winding direction, and the first and second reel stands rotate to remove slack in the tape and rotate the reel stand. A drive mechanism for a tape recorder, comprising: a tape end detection means for detecting when rotation stops; and an output from the tape end detection means to stop the drive means.