JPH06309746A - Rotary drum device - Google Patents

Abstract

(57) [Abstract] [Purpose] It is possible to reduce the occurrence of wrinkles and scratches on the tape due to the interference between the lower end of the tape and the lead portion of the drum during loading and unloading. [Structure] It is composed of a lower drum 1 and an upper drum 2,
Further, in a magnetic recording / reproducing apparatus having a rotating drum provided on the upper drum 2, the lead 3 regulating the running height so that the magnetic tape is linearly wound around the drum, interference between the lower end of the tape and the lead 3 is expected. Part of lead 3
On the other hand, the lead chamfering increasing portion 4 that increases the chamfering with respect to other portions is provided.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a rotary drum device in a magnetic recording / reproducing device such as a VTR (video tape recorder).

[0002]

2. Description of the Related Art FIG. 4 shows a conventional magnetic recording / reproducing apparatus (hereinafter, referred to as
FIG. 5 is a perspective view showing a schematic configuration of a rotary drum (referred to as VTR).

In the figure, 6 is a lower drum, and 7 is an upper drum which is arranged coaxially with the lower drum 6 and is rotatably mounted. The upper drum 7 is provided with a magnetic head (not shown) capable of writing (recording) a signal on a magnetic tape and outputting (reproducing) the written signal as an electric signal. Further, the lower drum 6 has a step 8 (hereinafter, this step is referred to as a lead) for running the magnetic tape in a straight line while skewing the magnetic tape. A magnetic tape (not shown) is wound around the lower drum 6 along the lead 8 in an Ω type. In FIG. 4, the angle display (0, 90 °, 180 °) shown on the upper part of the upper drum 7 is wound in the range of 0 ° → 90 ° → 180 ° when the magnetic tape is wound around the drum. It is shown that.

FIGS. 5 and 6 show a process in which a magnetic tape is wound around the rotary drum shown in FIG. In the figure,
Reference numeral 9 is a rotary drum composed of a lower drum and an upper drum, 10 is an inlet side fixed post provided near the entrance side of the rotary drum 9, 11 is an inlet side rotary post provided near the inlet side fixed post 10, and 12 is An outlet side fixed post provided near the outlet side of the rotating drum 9, 13 is an outlet side rotating post provided near the outlet side fixed post 12, and 14 is an inlet side rotating post 11 → an inlet side fixed post 10 → a rotating drum It is a magnetic tape that is attached by a route of 9 → outlet side fixed post 12 → outlet side rotating post 13.

Here, in order to record a signal on the magnetic tape 14, when the magnetic tape 14 is wound around the rotary drum 9 (hereinafter referred to as "loading"), the magnetic tape 1 is used.
4, the rotary drum 9, the inlet side fixed post 10, the inlet side rotary post 11, the outlet side fixed post 12, and the outlet side rotary post 13 move as shown in FIGS. 5 and 6.
FIGS. 7A to 7D are views in which the positional relationship between the magnetic tape 14 and the leads 8 in this process are two-dimensionally developed.
Here, FIG. 7A corresponds to FIG. 5, and FIG.
Corresponding to. 7 (b) and 7 (c) show the process in the middle of the process.

When the magnetic tape 14 and each post move as shown in FIGS. 5 to 6, (a), (b) and (c) of FIG.
The shaded portion shown in each of the figures interferes with the lead 8. Further, in the process of the tape separating from the rotary drum 9 when the tape cassette is taken out (hereinafter, this is referred to as “unloading”), interference occurs at the same position.

FIG. 8 shows the occurrence of interference between the tape and the lead at the time of loading, FIG. 9 shows the positional relationship between the tape and the lower drum and the lead when the loading is completed, and FIG. 10 shows the interference between the tape and the lead at the time of unloading. It is each sectional view showing.

[0008]

However, in the above-mentioned prior art, the lower end of the tape is bent because the lower end of the tape interferes with the rotary drum and the lead even during loading and unloading of the tape. Alternatively, there is a problem that excessive stress is partially applied and excessive force is partially applied, and the tape is wrinkled or scratched.

An object of the present invention is to provide a rotary drum device capable of reducing wrinkles and scratches generated on the tape due to interference between the lower end of the tape and the lead portion of the drum during loading and unloading. Especially.

[0010]

In order to achieve the above-mentioned object, the present invention according to claim 1 is provided with a lead portion for restricting a running height so that the magnetic tape is wound around the drum in a straight line. In a magnetic recording / reproducing apparatus having a rotating drum, chamfering is increased for a portion of the lead where interference between the lower end of the tape and the lead is expected, with respect to other portions. By eccentricizing the outer peripheral surface of the lower drum, the ratio of the lead portion to the chamfered portion is continuously converted.

[0011]

According to the above-mentioned means, the chamfering amount becomes large with respect to the lead portion where the tape and the lead portion easily interfere with each other. As a result, conventionally, as shown in FIG. 8, the interference between the lower end of the magnetic tape and the lead portion is reduced, the bending of the tape edge is reduced, and it is possible to prevent the tape from being scratched or wrinkled.

[0012]

1 is a perspective view showing the overall construction of a rotary drum device according to the present invention, and FIG. 2 is a sectional view showing the details of the lead portion of the embodiment of FIG.

1 and 2, 1 is a lower drum, 2
Is an upper drum rotatably arranged on the lower drum 1. A magnetic head (not shown) for recording and reproducing signals on a magnetic tape is fixed to the upper drum 2. Further, 3 is a lead, and 4 is a lead chamfering increasing portion (a portion having a width b with respect to the width a of the lead 3).

As shown in FIG. 1, the lead chamfer increase portion 4
Is provided on a part of the lead 3, and its forming range is about 90 °.
~ 150 °. This range corresponds to the range in which the tape and the lead interfere during loading (or unloading) when the lead chamfering increasing portion 4 is not provided, as described in the related art. By providing the lead chamfering increasing portion 4, the bending of the magnetic tape can be minimized during loading (or unloading) of the magnetic tape. It should be noted that the range of formation of the lead chamfering increasing portion 4 described above varies depending on the loading method.

As described above, the chamfered portion of the lead is loaded between the lead of the rotary drum (or when unloaded), and the chamfered portion of the lead between the point where the magnetic tape starts to contact the rotary drum and the point where the magnetic tape separates from the winding side. It is possible to prevent the edge of the tape from being easily bent and to prevent the magnetic tape from being scratched or wrinkled by continuously increasing the size of the lead portion.

FIG. 3 is a plan view showing another embodiment of the present invention.

In this embodiment, the width of the lead 3 is changed while keeping the lead chamfering amount constant. That is, the outer peripheral surface of the lower drum is eccentric when the lead 3 is cut during the processing of the lower drum 1. By doing this, the ratio of the lead part to the chamfer changes continuously,
Moreover, the width of the lead 3 of the interference portion 5 is reduced. Therefore, it is possible to obtain the same effect as that of the embodiment shown in FIGS.

[0018]

As described above, according to the present invention, in the magnetic recording / reproducing apparatus having the rotary drum provided with the lead portion for regulating the traveling height so that the magnetic tape is wound linearly, Since the chamfering of the lead in the portion where the lead interference is expected is increased with respect to other portions, the interference between the lower end of the tape and the lead portion is reduced, and the bending of the tape edge is reduced. , It is possible to prevent scratches and wrinkles on the tape.

[Brief description of drawings]

FIG. 1 is a perspective view showing an overall configuration of a rotary drum device according to the present invention.

FIG. 2 is a sectional view showing details of a lead portion of the embodiment of FIG.

FIG. 3 is a plan view showing another embodiment of the present invention.

FIG. 4 is a perspective view showing a schematic configuration of a rotary drum of a conventional magnetic recording / reproducing apparatus.

5 is an explanatory diagram showing a state immediately before the magnetic tape is wound around the rotary drum shown in FIG. 4. FIG.

FIG. 6 is an explanatory view showing a state in which the magnetic tape is wound around the rotary drum from the state of FIG.

FIG. 7 is an explanatory diagram showing a tape interval with respect to a drum when a positional relationship between a magnetic tape and a lead is developed in a plane.

FIG. 8 is an explanatory diagram showing a state where interference between the tape and the lead occurs during loading.

FIG. 9 is an explanatory diagram showing a positional relationship of the tape with respect to the lower drum and the lead when the loading is completed.

FIG. 10 is an explanatory diagram showing interference between the tape and the lead during unloading.

[Explanation of symbols]

 1 Lower Drum 2 Upper Drum 3 Lead 4 Lead Chamfering Increased Part 5 Interference Part

Claims (2)

[Claims] 1. A magnetic recording / reproducing apparatus having a rotary drum provided with a lead portion for regulating a running height so that a magnetic tape is wound linearly, in a portion where interference between a lower end of the tape and the lead is expected. A rotary drum device, wherein chamfering of the lead is increased with respect to other portions. 2. The rotary drum device according to claim 1, wherein the outer peripheral surface of the lower drum is eccentric to continuously change the ratio of the lead portion to the chamfered portion.