JPH0135356Y2 - - Google Patents

Description

[Detailed explanation of the invention] This invention is a videotape recorder (hereinafter referred to as
This paper relates to improvements to the tape count roller for VTRs (referred to as VTRs).

Conventionally, the tape count roller of a VTR has been provided with a rotation detection section, and by detecting the rotation speed of the tape count roller, the rotation speed has been controlled, the operating time, etc. have been performed.

FIG. 1 is a cutaway view showing a conventional tape counting roller. In the figure, a roller 2 around which a tape 1 is wound is supported by a bearing 4 attached to a shaft 3, and the roller 2 rotates as the tape 1 runs. Also, this tape 1 is connected to tape guides 8a and 8.
The movement position in the width direction is regulated by b.
A disk 5 is provided at the lower end of the roller 2 so that its center coincides with the central axis of the shaft 3, and a disk 5 is provided slightly inside the circumference of the disk 5 at an equiangular pitch with respect to the center of the disk 5. , and small holes 6 are formed to constitute a rotation pulse generating section. As the roller 2 rotates, the disc 5 also rotates, and a small hole 6 formed in the disc 5 is rotated.
generates a pulse signal in the photo coupler 7 as a rotation detecting section, and by reading this pulse signal with a counter (not shown), it is possible to know, for example, the amount of tape movement.

However, in the conventional tape count roller, tape waste and dust easily enter from the gap between the upper end surface of the tape guide 8b and the roller 2 and the space 10 near the photo coupler 7, and these intruders block the light from the photo coupler 7. This method has the drawback of easily causing erroneous counts.

Therefore, an object of this invention is to provide a tape counting roller that prevents tape scraps and dust from entering the roller, thereby preventing erroneous counting.

In order to achieve this purpose, this idea
A concave circumferential part provided at the lower end of the roller and a convex circumferential part provided on the tape guide form a wall to prevent dust from entering.
A rotation pulse generation section and a rotation pulse detection section are housed in the empty chamber protected by this dust intrusion prevention wall. This invention will be explained in detail below using examples.

FIG. 2 is a cutaway view showing an embodiment of this invention, and the same parts as in FIG. 1 are designated by the same symbols. In the figure, a cylindrical portion 15 whose center coincides with the center line of the shaft 3 is provided at the lower end of the roller 2, and small holes 16 as rotation pulse generating portions are bored below the cylindrical portion 15 at equiangular pitches with respect to the center. ing. The cylindrical portion 15 is inserted into the cutout portion of the photo coupler 7 up to a portion slightly above the small hole 16 in a non-contact state. Further, at the lower end of the roller 2, the cylindrical portion 15
A concave circumferential portion 20 is provided on the outer side. A convex circumferential portion 21 is provided on the upper end surface of the tape guide 8b, and is inserted into the concave circumferential portion 20 at the lower end of the roller 2 in a non-contact state. The portion 21 forms a barrier for preventing dust from entering.

The operation of the tape count roller according to the invention configured as described above is as follows. A bearing 4 in which a roller 2 wrapped with a tape 1 is disposed on a shaft 3
The tape 1 rotates as the tape 1 runs.
Due to this rotation, the cylindrical part 15 also rotates together with the roller 2, so the small hole 1 formed in the cylindrical part 15
6 blocks light from a photo coupler 7 as a rotation detecting section in accordance with the rotation speed, and generates a pulse signal from the photo coupler 7.

At this time, as the tape runs, the tape guide 8
Even if abrasion powder is generated from the tape sliding with b, it is blocked by the convex circumferential portion 21 and does not enter the photo coupler 7. In addition, the photo cutter 7 is housed in a chamber 22 that is protected by a barrier for preventing dust from entering, which is formed by a concave circumferential portion 20 and a convex circumferential portion 21, so that it is in a substantially airtight state, so that dust cannot enter from the outside. There is no need to worry about intrusion and erroneous counting.

As explained above, the tape counting roller according to this invention has a hollow chamber at the lower end of the roller to prevent dust from entering from the outside, and the rotation detecting section is housed in this hollow chamber, so tape waste and This has an excellent effect in that the rotation detecting section does not cause false detection due to dust or the like.

[Brief explanation of the drawing]

FIG. 1 is a sectional view showing an example of a conventional tape counting roller, and FIG. 2 is a sectional view showing an embodiment of the tape counting roller according to this invention. 1...Tape, 2...Roller, 3...Shaft, 4...
... Bearing, 5 ... Disc, 6, 16 ... Small hole, 7 ...
Foto Katsupura, 8a, 8b...tape guide,
9... Gap, 15... Cylindrical part, 20... Concave circumferential part, 21... Convex circumferential part.

Claims (1)

[Scope of utility model registration request] It has a roller around which the tape is wound, a tape guide that guides the tape in the width direction, a rotational pulse generation section that rotates integrally with the roller, and a rotation detection section that detects the rotation of the rotational pulse generation section. In the tape counting roller, a concave circumferential portion formed on the lower end surface of the roller, and a convex circle provided on the upper end surface of the tape guide so as to be inserted in a non-contact state with respect to the concave circumferential portion. a peripheral portion, and a cavity in which the concave circumferential portion and the convex circumferential portion formed inside the tape guide act as a barrier for preventing dust intrusion, and the rotational pulse generation unit and the rotational pulse detection unit is a tape counting roller disposed within the empty chamber.