JPH0664804B2 - Middle pole drive mechanism in magnetic tape recording / reproducing device - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to a mechanism for loading and unloading a middle pole of a magnetic tape recording / reproducing apparatus such as a video tape recorder (VTR).

(Prior Art) As shown in FIG. 4, the VTR has loading poles 30 and 30.
Magnetic tape 33 between the supply reel 31 and the take-up reel 32
Is wound around the drum 34 over a predetermined angle range, an image signal is recorded and reproduced by a rotary magnetic head provided on the drum 34, and an audio control head 35 provided at a position separated from the drum 34. The audio signal is recorded and reproduced. That is, since the image signal and the audio signal are recorded at positions separated from each other along the running direction of the magnetic tape, the image and the audio are reproduced without deviation regardless of the model of the VTR. It is necessary to always keep the interval between the recording / reproducing position by and the recording / reproducing position by the audio control head 35 constant.

Therefore, when the tape path is formed by the loading arm, the middle pole 36 pulls out and adjusts the magnetic tape 33 between the drum and the audio control head by a predetermined amount, and the tape contact state with the audio control head 35 is good. I have to.

If such a middle pole 36 is not fixed at the loading position, it may cause a discrepancy between the image and the sound and a defect in recording and reproducing the sound signal.
Middle pole moved to loading position at 37, 38
It is fixed by sandwiching 36.

(Problems to be Solved by the Invention) In the above-described conventional mechanism, the mechanism itself is complicated because a pawl that functions only to fix the middle pole at the loading position and a mechanism that drives these pawls are required. In addition, the number of parts is increased as a whole, and it becomes difficult to arrange other members.

(Means for Solving the Problems) In order to solve the above-mentioned problems, the present invention comprises a connecting arm that causes the middle pole to perform a loading operation and an unloading operation, or a connecting portion between the connecting arm and the middle pole arm is made of an elastic material. , The middle pole arm was urged to maintain the pivoted state to the loading position or the unloading position, respectively.

(Operation) When the middle pole arm pivots to the loading position, the middle pole arm is urged and fixed in the loading direction or the unloading direction by the connect arm made of an elastic material or the connecting portion with the connect arm. .

(Example) Below, the Example of this invention is described based on an accompanying drawing.

1 (A), (B) and (C) are plan views showing the essential parts of the middle pole drive mechanism according to the present invention in the order of operation, and FIG. 2 is an overall plan view of the drive mechanism.

As shown in FIG. 2, the drive mechanism of the middle pole transmits the rotation of the motor 2 fixed to the chassis 1 to the cam gear 6 through the gears 3, 4 and 5, and the cam groove 7 of the cam gear 6 transfers the rotation to the chassis 1. One end of a substantially S-shaped connect arm 8 which is rotatably supported via a shaft 8a is engaged, and the other end of the connect arm 8 is also rotated by the chassis 1 at its one end via a shaft 9a. The slotted hole 10 of the middle pole arm 9 which is pivotally supported is engaged with the pin 8b. A middle pole 11 is attached to the tip of the middle pole arm 9, and a rotation limit of the middle pole arm 9 in the unloading direction is restricted by a stopper 12 and a rotation limit of the middle pole arm 9 in the loading direction is restricted by a catcher 13. A tilt pole 14 is attached to the catcher 13.

Here, the connecting arm 8 is made of an elastic material such as a leaf spring, and its size and shape are related to the middle pole arm 9 and the middle pole arm 9 is unloaded at the unloading position shown in FIG. It is biased in the loading direction, that is, the stopper 12 direction, and is biased in the loading direction, that is, the catcher 13 direction at the loading position shown in FIG.

In the above, when the motor 2 is driven, the gear trains 3, 4, 5
The cam gear 6 rotates via. Further, the driving force is distributed from the gear 5 to other gear trains, and the loading arm and the cam encoder are rotated via a gear (not shown).

When the cam gear 6 rotates counterclockwise in FIG. 1, the connect arm 8 rotates counterclockwise about the shaft 8a as the rotation of the cam gear 6 increases.
The middle pole arm 9 engaging with 8b through the elongated hole 10 is the shaft 9a.
It rotates in the clockwise direction centering around, and after the state shown in FIG. 1 (B), the tip end of the middle pole arm 9 comes into contact with the catcher 13 as shown in FIG. 1 (C). Then, after that, the cam gear 6 further rotates counterclockwise by a predetermined amount to deform the connect arm 8 in a compressing direction, and the elastic force thereof becomes a pressing force for pressing the middle pole 9 against the catcher 13, Thus, the middle pole arm 9 is fixed at the loading position, that is, the middle pole 11 is fixed at the correct loading position.

On the other hand, by rotating the cam gear 6 in the clockwise direction, the cam gear 6 is moved to the unloading position by following the opposite route. Also in this case, the unloading position is maintained by the elastic force of the connect arm 8 by devising the shape of the cam groove 7 and the like as in the movement to the loading position. That is, after the tip of the middle pole arm 6 contacts the stopper 12, the cam gear 6 further rotates in the clockwise direction by a predetermined amount, whereby the connect arm 8 is deformed and the elastic force of the connect arm 8 stops the middle pole arm 9. It becomes the crimping force in the direction of pressing on 12 (the unloading direction opposite to the above),
As a result, the middle pole arm 9 is fixed at the unloading position, that is, the middle pole 11 is fixed at the correct unloading position.

As a result, the middle pole 11 can be fixed at a position corresponding to the cutout portion of the cassette, so that it is possible to reliably prevent the tape from being damaged by coming into contact with the tape when the cassette is mounted.

FIG. 3 is a view showing another embodiment. In this embodiment, the connect arm 8 is made of a material having high rigidity, and the pin 8a of the connect arm is formed on the elongated bifurcated portion 9b formed on the middle pole arm 9. By engaging with each other and obtaining an elastic force at the bifurcated portion 9b, the middle pole 11 is fixed to the correct position by the elastic force at the loading position and the unloading position.

(Effect) As described above, according to the present invention, since the connect arm or the connecting portion between the connect arm and the middle pole arm is made of the elastic material, the loading position and the unloading position can be set on the member for driving the middle pole. Since the function of fixing the middle pole at the position is also added, the number of parts can be reduced and the mechanism can be simplified, and the degree of freedom in arranging other members can be increased.

[Brief description of drawings]

1 (A), (B), and (C) are plan views showing the essential parts of the middle pole drive mechanism according to the present invention in the order of operation, and FIG. 2 is an overall plan view of the drive mechanism, and FIG. Is a view showing another embodiment, and FIG. 4 is a plan view showing a conventional mechanism. 6 ... Cam gear, 8 ... Connect arm, 9 ... Middle pole arm, 11 ... Middle pole.

Claims (1)

[Claims] 1. A middle pole drive mechanism in a magnetic tape recording / reproducing apparatus for transmitting a driving force from a cam gear to a middle pole arm via a connect arm to cause the middle pole to perform a loading operation and an unloading operation. A middle pole driving mechanism in a magnetic tape recording / reproducing apparatus, characterized in that a connecting portion between the arm and the middle pole arm is made of an elastic material, and the middle pole arm is biased so as to maintain a loading position and an unloading position. .