GB2308722A

GB2308722A - Head drum assembly

Info

Publication number: GB2308722A
Application number: GB9626911A
Authority: GB
Inventors: Yun-Won Yang
Original assignee: Daewoo Electronics Co Ltd
Current assignee: WiniaDaewoo Co Ltd
Priority date: 1995-12-26
Filing date: 1996-12-24
Publication date: 1997-07-02
Also published as: KR970050266A; GB9626911D0; JPH09231529A

Description

HEAD DRUM ASSEMBLY FOR USE IN A DIGITAL VIDEO CASSETTE RECORDER The present invention relates to a digital video caseette recorder (hDvCRIl); and, more particularly, to a head drum assembly for use in the DVCR, the assembly being capable of maintaining a proper contact with a video tape to thereby prevent operational failuree, e.g., noise or distortion, from occurring during the operation of the DVCR.

As is well known, a head drum assembly for use in a digital video cassette recorder (DVCR) comprises a plurality of moving parts, e.g., a rotary drum, and stationary parts, e.g., a stationary drum. In general, a video tape loaded in the DVCR travels along a given path provided on a deck of the DVCR and comes in contact with a head drum to record video information thereon or reproduce recorded information therefrom. however, since width of the head drum assembly for use in the DVCR ie small and the head drum assembly is rotated at a high speed, the video tape may not be able to maintain a proper contact with the head drum, causing operational failures, e.g., noise or distortion. Therefore, in order to prevent such failures, a way must be devised for ensuring the video tape to maintain a proper pressure contact with the head drum assembly.

In Fig. t-, there is presented a schematic cross sectional view of a head drum assembly 100 for use in a DVCR previously disclosed. The head drum assembly 100 comprises a stationary shaft 50 being provided with a pair of bearings 80, 85 and a motor stator 65, an upper drum 10 having a motor rotor 60 and a pair of heads 30, a lower drum 20 being provided with a stator transformer 75, and a rotary member 40 including a rotor transformer 70.

The upper drum 10 is rotationally fitted around the stationary shaft 50 with the rotary member 40 intervening, and is provided with the motor rotor 60 and the pair of heads 30 on top and bottom thereof, respectively.

The lower drum 20 is fitted and fixed around a lower portion of the stationary shaft 50, and is provided with the stator transformer 75 on top thereof. The upper and the lower drums 10, 20 maintain a certain gap therebetween. The pair of heads 30 on the upper drum 10 are located in the gap between the upper and the lower drums 10, 20.

The rotary member 40 is located between the upper and the lower drums 10, 20, while being attached on bottom of the upper drum 10 and the pair of heads 30, and is fitted to the stationary shaft 50 with the two sets of bearings 80, 85 intervening in such a way that it is rotated about the stationary shaft 50 during the operation of the head drum assembly 100.

Since the upper drum 10 is physically connected to the rotary member 40 and the pair of heads 30, it is rotated with the rotary member 40 and the pair of heads 30 about the stationary shaft 50 during the operation of the head drum assembly 100, thereby functioning as a rotary drum in the head drum assembly 100. However, since the lower drum 20 is fixed to the stationary shaft 50, even though the upper drum 10 is rotated during the operation of the head drum assembly 100, it is not rotated with the stationary shaft 50, thereby functioning as a stationary drum in the head drum assembly 100.

The rotor transformer 70 ie located on bottom of the rotary member 40 in such a way that it is aligned with the stator transformer 75 located on the lower drum 20 but separated by a predetermined gap from the stator transformer 75.

The motor stator 65 is fitted and fixed on top of the stationary shaft 65 in such a way that it is aligned with the motor rotor 60 located on the upper drum 10 but separated by a predetermined gap from the motor rotor 60.

When an electric signal is applied to the motor stator 65, an electromagnetic force is generated between the motor stator 65 and the motor rotor 60. The upper drum 10, the rotary member 40, the rotor transformer 70, the pair of heads 30 and the motor rotor 60 are rotated about the stationary shaft 50 by the electromagnetic force between the motor stator 65 and the motor rotor 60.

The rotor transformer 70 is electrically connected to the pair of heads 30. Accordingly, during the reproducing operation of the DVCR, the rotor transformer 70 receives the video information recorded on the video tape from the pair of heads 30, and then provides the video information from the pair of heads 30 to the stator transformer 75. Furthermore, during the recording operation of the DVCR, the rotor transformer 70 receives the video information from the stator transformer 75, and then provides the video information from the stator transformer 75 to the pair of heads 30.

There are a number of shortcomings associated with the above described head drum assembly 100 ehown in Fig. 1, however. Since the upper drum 10 functions as a rotary drum in the head drum assembly 100 by being rotated about the stationary shaft 50, during the operation of the head drum assembly 100, a tension on the video tape coming in contact with the upper drum 10 is difficult to maintain, resulting in an irregular contact therebetween, which will, in turn, cause operational failures, e.g., noiee or distortion, in the DVCR.

It is, therefore, a primary object of the present invention to provide a head drum assembly for use in an digital video cassette recorder, the assembly being capable of maintaining a proper contact with a video tape to thereby prevent operational failures, e.g., noise or distortion, from occurring during the operation of the DVCR.

In accordance with one aspect of the present invention, there is provided a head drum assembly for use in a DVCR, the head drum assembly comprising: a stationary shaft having an upper and a lower end portions, the stationary shaft including bearing means on a side surface thereof; an upper drum fitted and fixed around the upper end portion of the stationary shaft, the upper drum having a stator transformer; a lower drum fitted and fixed around the lower end portion of the stationary shaft, the lower drum being provided with a motor stator, wherein the lower drum maintains a constant gap from the upper drum; a rotary member fitted to the stationary shaft with the bearing means intervening, the rotary member being provided with a rotor transformer and a motor rotor; and a plurality of heads, each of the heads being attached to the rotary member in such a way that it ie located in the gap between the upper and the lower drums.

The above and other objects and features of the present invention will become apparent from the following description of the preferred embodiments, when given in conjunction with the accompanying drawinge, wherein: Fig. 1 presents a schematic cross sectional view of a head drum assembly for use in a digital video cassette recorder previously disclosed; and Fig. 2 provides a schematic cross sectional view of a head drum assembly for use in a digital video cassette recorder in accordance with the present invention.

There is provided in Fig. 2 a schematic cross sectional view of a head drum assembly 200 for use in a digital video cassette recorder (DVCR) in accordance with the present invention. It should be noted that parts similar to those previously described with reference to Fig. 1 are represented by an annexing numeral 100 with like reference numerals.

The head drum assembly 200 includes a stationary shaft 150 being provided with a pair of bearings 180, 185, an upper drum 110 having a stator transformer 175, a lower drum 120 being provided with a motor stator 165, and a rotary member 140 including a motor rotor 160, a rotor transformer 170 and a pair of heads 130.

The upper drum 110 is fitted and fixed around upper end portion of the stationary shaft 150, and is provided with the stator transformer 175 on bottom thereof.

The lower drum 120 is fitted and fixed around lower end portion of the stationary shaft 150, and is provided with the motor stator 165 on top thereof. The lower drum 120 maintains a certain gap with the upper drum 110.

The rotary member 140 is fitted to the stationary shaft 150 with the two sets of bearings 180, 185 intervening, in such a way that it is rotated about the stationary shaft 150 during the operation of the head drum assembly 200. The rotary member 140 is provided with the rotor transformer 170 and the motor rotor 160 on top and bottom thereof, respectively, in such a way that the rotor transformer 170 and the motor rotor 160 are reepectively aligned with the stator transformer 175 and the motor stator 165. The pair of heads 130 is attached to the rotary member 140 in such a way that it is located in the gap between the upper and the lower drums 110, 120.

Since the upper and the lower drums 110, 120 are respectively fixed to the upper and the lower end portions of the stationary shaft 150, even though the rotary member 140 and the pair of heads 130 are rotated about the stationary shaft 150 during the operation of the head drum assembly 200, the upper and the lower drums 110, 120 are not rotated, thereby functioning as stationary drums in the head drum assembly 200.

When an electric signal is applied to the motor stator 165, an electromagnetic force is generated between the motor stator 165 and the motor rotor 160. The rotary member 140, the rotor transformer 170, the pair of heads 130 and the motor rotor 160 are rotated about the stationary shaft 150 by the electromagnetic force between the motor stator 165 and the motor rotor 160.

The rotor transformer 170 is electrically connected to the pair of heads 130. Accordingly, during the reproducing operation of the DVCR, the rotor transformer 170 receives the video information recorded on the video tape from the pair of heads 130, and then provides the video information from the pair of heads 130 to the stator transformer 175. Furthermore, during the recording operation of the DVCR, the rotor transformer 170 receivee the video information from the stator transformer 175, and then provides the video information from the stator transformer 175 to the pair of heads 130.

In the inventive head drum assembly 200 for use in the DVCR, since the upper drum 110 as well as the lower drum 120 function ae stationary drums in the head drum assembly 200, that is, the upper drum 110 is not rotated about the stationary shaft 150, an optimum tension force on the video tape coming in contact with the upper drum 110 can be maintained, allowing the video tape to provide a proper contact with the head drum assembly 200. As a result, operational failures, e.g., noise or distortion, may be prevented.

While the present invention has been described with respect to certain preferred embodiments only, other modifications and variations may be made without departing from the scope of the present invention as set forth in the following claims.

Claims

What is claimed ie:

1. A head drum assembly for use in a DVCR, the head drum assembly comprising: a stationary shaft having an upper and a lower end portions, the stationary shaft being provided with bearing means; an upper drum fitted and fixed around the upper end portion of the stationary shaft, the upper drum having a stator transformer; a lower drum fitted and fixed around the lower end portion of the stationary shaft, the lower drum being provided with a motor stator, wherein the lower drum maintaine a constant gap from the upper drum; a rotary member fitted to the stationary shaft with the bearing means intervening, the rotary member being provided with a rotor transformer and a motor rotor; and a plurality of heads, each of the heads being attached to the rotary member in such a way that it is located in the gap between the upper and the lower drums.

2. The assembly of claim 1, wherein the motor rotor is located on bottom of the rotary member.

3. The assembly of claim 2, wherein the motor stator is located on top of the lower drum.

4. The assembly of claim 3, wherein the motor rotor is aligned with the motor stator.

5. The assembly of claim 1, wherein the rotor transformer is located on top of the rotary member.

6. The assembly of claim 5, wherein the etator transformer is located on bottom of the upper drum.

7. The assembly of claim 6, wherein the rotor transformer is aligned with the stator transformer.