JPH01298559A - Tape tension control mechanism - Google Patents

Abstract

PURPOSE:To obtain the tape tension control mechanism capable of suppressing variations of tape tension even when a tape wound diameter is changed by moving a fixing end of a band brake in response to an output of a detecting means for detecting the variations of the tape wound diameter of a tape supply reel. CONSTITUTION:The number of reel revolutions 32 of the supply reel 3 is detected by a reel revolution detector 28 and then calculated by a reel FG 31, and this is frequency-voltage converted 33. This value is impressed 34 on a loading motor 15, which is a motor for controlling tension regulation, to allow a tension regulating fixed end moving base 7 to move 35, so as to suppress the variations in the tension by changing the tension according to the number of reel revolutions, i.e., the tape wound diameter. By this method, the tape tension is not changed even when the tape wound diameter is changed, and hence the precise tension control is feasible.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a tape tension control wm structure that controls tape tension at a constant level.

[Prior Art] As a tension control device for controlling the tension of a tape or the like, there is a tape tension control mechanism used in a video tape recorder (VTR), and this tape tension control mechanism will be described below as an example.

FIG. 4 is a diagram showing the tape tension control mechanism of a conventional VTR. In the figure, l is a tension arm, 2 is a band brake, 3 is a supply reel, 4 is a tension spring, 5 is a magnetic tape, and 6 is a tension bin. It is.

In the above configuration, fluctuations in tape tension move the tension arm 1, thereby changing the friction torque between the bunt brake 2 and the supply reel 3, thereby suppressing fluctuations in tape tension.

FIGS. 2(a) and 2(b) are explanatory diagrams illustrating the relationship between tape winding radius and tape tension in the conventional method and the present invention. Figure 2 (b) shows the tape winding radius on the horizontal axis and the tape tension on the vertical axis, where the curve (a) represents the tape tension of the conventional tape tension control mechanism.
The curve (b) represents the tape tension of the mechanism of this invention.

As is clear from FIG. 2(b), according to the conventional tape tension control mechanism, the tape tension also changes as the tape winding radius changes.

[Problems to be Solved by the Invention] The conventional tape tension control mechanism as described above suppresses fluctuations in tape tension, but has the drawback that the tape tension changes depending on the tape winding radius (minimum diameter and maximum diameter). .

The present invention has been made in view of the above problems, and an object of the present invention is to provide a tape tension control mechanism that can suppress changes in tape tension even if the tape winding radius changes.

[Means for Solving the Problems] In order to achieve the above object, the tape tension control mechanism of the present invention includes a tension arm that rotates according to the tension of the tape, and a band brake coupled to the tension arm. , a detecting means for detecting a change in the tape winding radius of the tape supply reel, and a moving mechanism for moving the fixed end of the band brake in accordance with the output of the detecting means.

[Function] According to the above-mentioned configuration, reliable tension control can be performed without providing a motor exclusively for tension control, even if, for example, a loading motor that only uses loading is used.

[Embodiment] The structure and operation of an embodiment of the tape tension control mechanism of the present invention will be described below with reference to FIGS. 1 to 3.

FIG. 1 is a diagram showing the configuration of a tape tension control mechanism a according to an embodiment of the present invention, and FIG. 3 is a block diagram of the tape tension control mechanism of the present invention.

In Fig. 1, 13 is a gear, and the loading motor 1
It has a structure that meshes with the gear 14 attached to 5 by moving. Further, 10 connected to the gear 13 is a worm gear, 11.9 is a gear, and each gear 13, 11,
10.9 is movable together with the gear moving table 12. Reference numeral 8 denotes a rack gear which is integrated with the fixed end moving base 7 of the ten-leg gear. This balance gear fixed end moving base 7 is coupled to the band brake 2. A loading detection rod 25 moves when loading is completed, and is linked to a loading switch 26. 27 is the first post, 16-24
Reference numerals a and 24b indicate respective parts of a conventional loading mechanism, and their explanation will be omitted since they are not directly related to the gist of the present invention. Further, in FIG. 1, the same reference numerals as in FIG. 4 indicate the same or corresponding parts.

To explain the above configuration, the loading detection rod 25 is moved by the loading mechanism parts 16 to 24a and 24b when loading is completed, and the loading switch 26 attached to the end of the loading detection rod 25 is operated, and the loading motor 15 is activated by the ten-leg. Replaces the control motor. At the same time, the gear moving table 12 is moved to engage the gears 13 and 14. Then, the rotational force of the loading motor 15 or the gear 14
From gear 13. Ohm gear lO, gear 11. Gear 9.
The loading motor 15 moves the ten-leg fixed end moving table 7, which is transmitted to the rack gear 8 and is integrated with the rack gear 8.
It will be moved by

The control shown in FIG. 1 will be explained below based on FIG. 3.

The reel rotation speed (32) of the supply reel 3 is detected by the reel rotation speed detector 28 and calculated from the reel FG (31), which is frequency-voltage converted (33). This value is used as the motor for controlling the ten-leg gear. Applied to the loading motor 15 (3
4) Move the fixed end moving base 7 using L/key (35) L
/ is changed in accordance with the reel rotation speed, that is, the winding radius of the tape, thereby suppressing changes in tension.

Here, using FIG. 2, it will be explained that the tension changes depending on the tape winding radius. First, the winding angle of the post 27 changes between the minimum diameter and the maximum diameter, and the tension loss there becomes the maximum diameter < the minimum diameter. Further, the force for drawing out the tape from the supply reel 3 also becomes the maximum diameter and the minimum diameter, and the tape tension changes as shown in FIG. This rate of change is calculated once the location of each component, post diameter, and other factors are determined.

[Effects of the Invention] As explained above, according to the tape tension control mechanism of the present invention, the tape tension does not change even if the tape winding radius changes, making it possible to perform precise tension control.

[Brief explanation of the drawing]

FIG. 1 is a diagram showing the configuration of a tape tension control mechanism according to an embodiment of the present invention, and FIGS. 2(a) and 2(b) are explanations explaining the relationship between tape winding radius and tape tension in the conventional method and the present invention. 3 are block diagrams of the tape tension control mechanism of the present invention, and FIG. 4 is a diagram showing the tape tension control mechanism of a conventional VTR. In the figure. l: Tension arm 2: Band brake 3: Supply reel 4; Tension spring 5: Magnetic tape 6: Tension pin 7: Ten leg fixed end moving base 8 Neck gear 10: Worm gear 12: Gear moving base 9.11, 13, 14: Gear 15: Loading motor 25: Loading detection rod 26: Loading switch 28: Reel rotation speed detector Attorney ± IP Kita Takashi Figure 1 Figure 3 Figure 4

Claims (1)

[Claims] A tension arm that rotates according to the tension of the tape, a band brake connected to the tension arm, a detection means that detects a change in the tape winding radius of the tape supply reel, and a band brake that rotates according to the output of the detection means. A tape tension control mechanism characterized by comprising a moving mechanism for moving a fixed end of a brake.