1. Field of the Invention
The present invention relates to a tension arm driving apparatus for a video cassette tape recorder, and particularly to an improved tension arm driving apparatus for a video cassette tape recorder capable of achieving a stable running state of a tape by preventing a tape jog in a high speed tape rewinding mode.
2. Description of the Conventional Art
Referring to FIG. 1, the conventional tension arm driving apparatus for a video cassette tape recorder includes a tension arm 2 rotatably engaged to a shaft pin 1 fixed to a predetermined portion of a main base 20, a tension post 3 fixed to an end of the tension arm 2, a tension spring 4 engaged to a predetermined portion of the tension arm 2 for elastically supporting the tension arm 2 in a certain direction, a cam gear 7 rotatably engaged to the shaft pin 6 and spaced apart from the tension arm 2 in cooperation with a cam groove 5, and an operation plate 10 linearly reciprocating above the main base 20 in cooperation with the cam pin engaged to an engaging pin 8 contacting with one end 2a of the tension arm 2 and the cam groove 5.
The operation of the conventional tension arm driving apparatus for a video cassette tape recorder will now be explained.
To begin with, when the cam gear 7 rotates, since the cam pin 9 of the operation plate 10 is inserted into the cam groove 5 formed on a predetermined portion of the cam gear 7, the operation plate 10, as shown in FIG. 1, moves either in the rightward or leftward direction and drives the tension arm 2.
For example, when the operation plate 10 moves in the leftward direction, as indicated by the arrow as shown in FIG. 1, since the end 2a of the tension and 2 engages with the engaging pin 8 of the operation plate 10, the tension arm 2 is moved by the elastic force of the tension spring 4 and rotates in the clockwise direction about the shaft pin 1.
However, on the contrary, when the operation plate 10 moves in the rightward direction, the tension arm 2 rotates counterclockwise about the shaft pin 1 by the recovering force of the tension spring 4 about the shaft pin 1.
The tension post 3 fixed to the tension arm 2 guides the running operation of a tape T in accordance with the rotation operation of the tension arm 2. In case of using a 8 mm cameorder tape damage occurs due to shape of the cassette while the tape T is conveyed therein without a certain loading therein, due to the shape of the cassette. So, as shown in FIG. 1, the tape T is conveyed in a state where the tape T is presented therein.
However, the conventional tension arm driving apparatus for a video cassette tape recorder has disadvantages in that since the tension arm moves in only one direction by the engaging pin of the operation plate, the tension arm becomes jogged in the tape rewinding mode by the tension force of a running tape, so that the running state of the tape becomes unstable. In particular, in case of using a 8 mm tape, malfunction may occur in the system because the tape comes off from its running path.