Dynamic magnetic information storage or retrieval – Head mounting – For moving head during transducing
Reexamination Certificate
1999-11-16
2001-06-12
Tupper, Robert S. (Department: 2652)
Dynamic magnetic information storage or retrieval
Head mounting
For moving head during transducing
Reexamination Certificate
active
06246550
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to a head drum for a recording and reproducing apparatus, and in particular to a head drum for a recording and reproducing apparatus which is capable of enhancing a reliability of a grounding apparatus which implements an electric connection between an upper drum and a lower drum of a head drum and preventing a noise due to a grounding apparatus during an operation of the head drum.
2. Description of the Background Art
FIG. 1
is a view illustrating the construction of a fixed type head drum for a recording and reproducing apparatus. The construction of the head drum is as follows.
A lower drum is press-fitted onto a lower portion of a center shaft
30
, and an upper drum
20
is rotatably engaged at an upper portion of the same by interleaving upper and lower bearings
21
a
and
21
b.
A head drum
22
is installed at the upper drum
20
for recording a signal into a tape and reproducing the signal recorded on the tape, and a rotor
23
is engaged at an upper drum
20
by an engaging screw
24
for rotating the upper drum
20
.
A stator
25
is fixed at an upper portion of the center shaft
30
for rotating the rotor
23
by an electric operation with the rotor
23
.
In the head drum for a recording and reproducing apparatus, the upper drum
20
is insulated by a lubricant formed on bearing balls(not shown) of the upper and lower bearings
21
a
and
21
b
for thereby being electrically separated from the lower drum
10
.
Therefore, a head drum grounding apparatus is installed below the stator
25
for an electrical connection of the lower drum
10
and the upper drum
20
. The construction of the conventional head drum grounding apparatus will be explained with reference to
FIGS. 2 and 3
.
FIG. 2
is a cross-sectional view illustrating the portion A of
FIG. 1
which illustrates a conventional head drum grounding apparatus, and
FIG. 3
is an exploded perspective view illustrating the construction of a conventional head drum grounding apparatus.
As shown therein, the conventional head drum grounding apparatus includes a ring collar
40
and a tip brush
50
.
The ring collar
40
includes an insertion hole
41
into which the center shaft
30
is inserted. An engaging hole
42
communicates with the center shaft
30
in a horizontal direction. The ring collar
40
is engaged to the center shaft
30
using the engaging screw
30
via the engaging hole
42
.
An installation hole
44
is formed at one side of the ring collar
40
for engaging a tip brush
50
which will be described later.
The tip brush
50
contacts with the upper drum
20
for electrically connecting the upper drum
20
and the lower drum
10
. As shown in
FIG. 3
, there is provided a brush body
51
made of a carbon material, and a ground spring
52
is fixed at a portion of the brush body
51
.
The brush body
51
includes a semicircular contact portion
51
a
and a connection portion
51
b
at both ends of the brush body
51
. On end of the brush body
51
, namely, a contact portion
51
a
contacts with the upper bearing
21
a
, the other end of the brush body
51
, namely, a connection portion
51
b
is fixed at the ground spring
52
.
One end of the ground spring
52
is connected with the connection portion
51
b
of the brush body
51
using a conductive adherent material
53
.
In the thusly constituted head drum grounding apparatus, the tip brush
50
is installed at the installation hole
44
of the ring collar
40
, and one end of the tip brush
50
, namely, the contact portion
51
a
of the brush body
51
contacts with the upper bearing
21
a
by an elastic force of the ground spring
52
, and the other end of the tip brush
50
, namely, one end of the ground spring
52
contacts with a lower surface of the stator
25
.
In this state, the lower surface of the stator
25
is formed of a phenol which is an insulation material for thereby implementing an insulated state with the ground spring
52
. Therefore, the ground spring
52
contacts with an inner surface of the installation hole
44
of the ring collar
40
for thereby implementing a grounded state of the upper drum
20
.
In other words, the grounding path is as follows: the upper drum
20
→the upper bearing
21
a
→the contact portion
51
a
of the brush body
51
→the ground spring
52
→the inner surface of the installation hole
44
of the ring collar
40
→the center shaft
30
→the lower drum
10
. Therefore, a main substrate(not shown) of the recording and reproducing apparatus is grounded via the above-described paths.
In the conventional head drum grounding apparatus, a certain distance is formed between the installation hole
44
and the tip brush
50
so that the tip brush
50
is upwardly and downwardly movable by an elastic force of the ground spring
52
in the installation hole
44
of the ring collar
40
. Therefore, in the conventional art, a contact between the ground spring and the inner surface of the installation hole is not obtained due to the above-described distance, so that it is impossible to obtain an accurate grounding of the tip brush.
In addition, since the ratio between the length of the ground spring and the distance between the inner surface of the installation hole and the ground spring is relatively great, the ground spring may be flexed, so that the brush body
51
may be vibrated. A friction noise may occur at a contact portion of an inner wall of the installation hole
44
of the ring collar
40
due to the flexed grounding spring
52
.
The conduction adherent material used for fixing the ground spring
52
to the brush body
51
is protruded beyond the outer surface of the brush body
51
, so that it is difficult to install the tip brush
50
at the installation hole
44
of the ring collar
40
.
SUMMARY OF THE INVENTION
Accordingly, it is an object of the present invention to provide a head drum for a recording and reproducing apparatus which is capable of enhancing a reliability of a head drum grounding apparatus by obtaining a reliable grounding of a tip brush and preventing a noise which occurs at the tip brush.
To achieve the above objects, there is provided a head drum for a recording and reproducing apparatus according to the present invention which includes a lower drum installed at a lower portion of a center shaft, an upper drum rotating about the center shaft at an upper portion of the lower drum, and a head drum grounding apparatus which includes a grounding means formed of a contact member contacting with a portion of the upper drum and an elastic member fixed at an end of the contact member and having different diameters at its multiple steps, and a receiving means inserted into the center shaft and having an installation hole for receiving the grounding means.
Additional advantages, objects and features of the invention will become more apparent from the description which follows.
REFERENCES:
patent: 5442506 (1995-08-01), Kang
LG Electronics Inc.
Tupper Robert S.
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