JPH0519202B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a rotary head drive mechanism in an auto-reverse device for a tape recorder, and is characterized in that a cam for rotating the head and a cam for moving the head are mounted on the same rotating member. By staggering the operating timing of both cams on the top, only one cam gear is required, which simplifies the structure.Also, the rotation and movement of the rotary head can be reliably timed, eliminating any risk of malfunction. This is the missing point.

FIG. 1 shows a rotary head drive mechanism of a conventionally known auto-reverse device, and its structure and operation will be briefly explained.

A partially toothed gear 33a provided with a cam 33 for raising the head
and a partially toothed gear 32a provided with a head switching cam 32.
are driven by the capstan gear 4, and when not in operation, the partially toothed gear 33a is locked by the trigger lever 22, and the partially toothed gear 32a is locked by the trigger lever 25.
Each toothless portion is stopped facing the capstan gear 4.

Due to the excitation of the trigger plunger 21, the locking of the trigger lever 22 is released and the partially toothed gear 33a is released.
When the head is rotated, the lever 24 that engages the head raising cam 33 swings counterclockwise to raise the head (not shown) to a position where it contacts the tape.

When the trigger lever 25 is unlocked by excitation of the trigger plunger 26, the head rotation cam 32 rotates, the lever 27 swings, and the lever 28 supported at its tip causes the rotation arm 29 to be rotated. Rotate.

Two engaging recesses 29a and 29b are formed in the rotating arm 29, with which the tip of the lever 28 comes into contact, and as shown in FIG. The rotary arm 29 is rotated in the opposite direction, and the rotary head is rotated 180 degrees via the slide plate 15 connected to the lower end of the rotary arm 29.

When playing, the head is first raised to perform forward play, then lowered, rotated 180 degrees, and raised again to perform reverse play.

Since the two cams rotate independently in this way, the structure is complex, and the timing of the two trigger plungers must be precisely controlled. If the head switching cam 32 starts rotating for some reason (for example, due to a shock), the cassette half or tape recorder may be damaged.

An object of the present invention is to improve the drawbacks of the conventional devices described above, and to provide an auto-reverse device that has a simple structure, can accurately control operation timing, and has no fear of subsequent operation.

Embodiments of the invention will be described with reference to the drawings.

FIG. 3 shows a front view in the stopped state.

A cam gear 3 having two missing teeth is driven by a capstan gear 4, and in the state shown in the figure, when the hook 2 of the trigger lever 22
The claw 3a is locked and stopped by a.

A flywheel 5 to which a capstan gear 4 is fixed is driven by a motor 7 via a belt 8 together with a flywheel 6 rotating in the opposite direction.

A head rotating cam 32 is provided on the back side of the cam gear 3 (on the other side in the figure), and the pin 9a of the drive arm 9, whose center is pivotally supported by the chassis 20, comes into contact with the cam 32 and swings. It's getting old.

At the opposite end of the drive arm 9, the switching arm 1
An arm 12 that contacts and rotates the selection arm 1 is pivotally supported and biased toward the position shown in the figure, and when the switching plunger 10 is excited, the selection arm 1
1 to the position shown in FIG.

Drive pins 13a and 14a provided at the tips of the switching arms 13 and 14, respectively, are arranged in engagement recesses 15a of a slide plate 15 that moves in the left-right direction and rotates the rotary head 180 degrees. When the slide plate 14 rotates, the slide plate 15 is moved to the left or right, respectively.

A center-over reversing spring 16 is provided between the slide plate 15 and the chassis 20, thereby biasing the slide plate 15 toward the left end or right end.

A head lifting cam 33 is provided on the front side of the cam gear 3, and a pin 18 of the drive plate 18 moves vertically together with the head base (not shown).
a is in contact with the head lifting cam 33.

Next, its operation will be explained.

When the switching plunger 10 is energized, the selection arm 11 rotates and the arm 12 moves to the position shown in FIG.

Next, when the trigger plunger 1 is energized, the hook 2a of the trigger lever 2 is disengaged from the claw 3a, and the cam gear 3 is rotated slightly clockwise by the trigger spring 17, engages with the capstan gear 4, and starts rotating.

Then, as shown in Figures 5 and 6,
The drive arm 9 is rotated by the head rotation cam 32, and the arm 12 contacts the switching arm 14 to rotate it, and the slide plate 15 moves to the right.

The slide plate 15 rotates a head rotation gear (not shown) by means of a U-shaped engaging portion 15b, thereby directing the head in the forward direction.

Next, as shown in FIGS. 7 and 8, the drive plate 18 is raised by the head raising cam 33, and the head base connected to the drive plate 18 by a spring is raised, so that the head comes into contact with the tape.

The cam gear 3 rotates further and stops when its pawl 3a abuts the contact portion 2b of the trigger lever 2, as shown in FIG. 9, and forward play begins.

When the forward play is completed, as shown in FIG. 10, the excitation of the trigger plunger 1 is released and the trigger lever 2 is rotated clockwise by the trigger lever return spring 19 to close its contact portion 2.
b is removed from the pawl 3a, and the cam gear 3 starts rotating again.

Then, as shown in FIG.
The pin 18a of No. 8 comes into contact with the auxiliary cam 34 and lowers, and the head separates from the tape.

Next, as shown in FIG.
The pawl 3a engages with the hook 2a of the trigger lever 2, and the cam gear stops.

In the case of reverse play, the trigger plunger 1 is activated without energizing the switching plunger 10.
By energizing only the arm 12 of the drive arm 9, the arm 12 of the drive arm 9 contacts the switching arm 13 and rotates it clockwise, moving the slide plate 15 to the left, which changes the direction of the head in the reverse direction. operates in the same manner as described above and enters the reverse play state.

In the above embodiment, the head rotating cam and the head lifting cam are provided on different surfaces of the cam gear, but it is also possible to provide both on one surface.

Furthermore, although the above embodiment has been described with respect to a tape recorder in which the cassette halves are arranged vertically and played, it goes without saying that the tape recorder can also be used in a tape recorder in which the cassette halves are arranged horizontally.

As explained above, the auto-reverse device for a tape recorder of the present invention has a head rotation cam and a head movement cam provided on the same rotating member with the operation timings of both cams being shifted.
The structure is simple, the rotation and movement of the head can be reliably timed, and there is no risk of malfunction.

[Brief explanation of the drawing]

Fig. 1: A front view of a conventionally known auto-reverse device, Fig. 2: An explanatory diagram of the operation of the slide plate driving portion thereof, Fig. 3: A front view of an embodiment of the present invention in a stopped state, Fig. 4: FIGS. 7 to 6 are explanatory views of the operation of the head rotating mechanism, and FIGS. 7 to 12 are explanatory views of the operation of the head moving mechanism. 1...Trigger lever, 3...Cam gear, 9...
...Drive arm, 10...Switching plunger, 11
...Selection arm, 12...Arm, 13 and 14...
...Switching arm, 15...Slide plate, 18...Driving plate, 32...Cam for rotating the head, 33...Cam for lifting the head.

Claims (1)

[Claims] 1. A head rotating cam that rotates the rotating head half a rotation during auto-reverse and a head moving cam that moves the rotating head to a position where it contacts the tape are provided on the same rotating member with the operation timings of the two cams being staggered. An auto-reverse device for a tape recorder, characterized in that when the head moving cam moves the rotating head away from the tape due to the rotation of the rotating member, the head rotating cam rotates the rotating head half a rotation. .