Dynamic magnetic information storage or retrieval – Record transport with head moving during transducing – Tape record
Reexamination Certificate
1999-03-22
2001-11-06
Miller, Brian E. (Department: 2754)
Dynamic magnetic information storage or retrieval
Record transport with head moving during transducing
Tape record
Reexamination Certificate
active
06313965
ABSTRACT:
FIELD OF THE INVENTION
The present invention relates to a mechanism chassis for mounting a plurality of mechanisms thereon for use in devices, such as VCRs (video cassette recorders), having these mechanisms to realize a specified operation.
BACKGROUND OF THE INVENTION
FIG. 4
shows a mechanism chassis
10
which is conventionally used in VCRs. The mechanism chassis
10
comprises a polygonal flat plate portion
11
for mounting on the surface thereof mechanisms such as a rotary head cylinder, a capstan, a pair of reel supports, and four side plate portions
12
,
13
,
14
,
15
bent from the respective contour sides of the flat plate portion
11
toward the rear side of the plate portion
11
. The flat plate portion
11
is formed with an opening
16
for mounting the rotary head cylinder, and loading grooves
17
,
18
for mounting respective leading guide blocks for winding a magnetic tape around the rotary head cylinder.
To make the mechanism chassis
10
, a blank having the contour of the chassis
10
of
FIG. 4
as developed on a plane is cut out from a metal sheet having a thickness, for example, of 1.6 mm, and the blank is thereafter pressed to bend four side plate portions
12
,
13
,
14
,
15
extending from a flat plate portion
11
. A strain due to residual stress or the like will occur in the mechanism chassis
10
resulting from the press work, undulating the surface of the flat plate portion
11
.
Accordingly, the bulging-out parts and the curving-in parts of the surface undulations of the flat plate portion
11
are reversely deformed, eventually using a leveler to correct the flatness of the flat plate portion
11
. In this step, the mechanism chassis
10
has a sufficient thickness and therefore high rigidity, whereas the four side plate portions
12
,
13
,
14
,
15
, which are separated from one another, are free to deform at the separated portions B, so that the strain of the mechanism chassis
10
can be removed correctly by the eventual leveling work. As a result, the mechanism chassis
10
obtained has a high degree of flatness over the surface of the flat plate portion
11
.
Mechanisms of simpler construction have been developed in recent years to provide compacted VCRs of reduced weight. It is required that the mechanism chassis
10
be prepared also from a metal sheet of the smallest possible thickness.
However, if the sheet thickness of the mechanism chassis
10
is reduced excessively a lower structural strength will result, readily entailing deformation due to the action of an external force and consequently leading to the malfunctioning of mechanisms on the chassis
10
. Conventionally, therefore, there is a lower limit to the sheet thickness of the mechanism chassis
10
, and difficulty is encountered in reducing the weight of the mechanism chassis
10
.
SUMMARY OF THE INVENTION
An object of the present invention is to provide a mechanism chassis of reduced weight by making the chassis from a metal sheet having a smaller thickness than in the prior art.
The present invention provides a mechanism chassis comprising a polygonal flat plate portion
11
having a plurality of contour sides and a plurality of corners formed by intersection of the contour sides for arranging a plurality of mechanisms on a surface of the flat plate portion, and a plurality of side plate portions
12
,
13
,
14
,
15
bent from the respective contour sides of the flat plate portion
11
toward a rear side of the flat plate portion
11
, the mechanism chassis being characterized in that the pair of side plate portions adjacent to each other at at least one corner are separated from each other, the pair of side plates portions adjacent to each other at the corner or each of the corners other than said at least one corner being joined to each other.
According to the installation precision required for mounting the plurality of mechanisms on the flat plate portion
11
of the mechanism chassis of the invention, the flat plate portion
11
is divided into two regions, i.e., a chassis region where those of the mechanisms of which a relatively high precision is required are to be arranged (hereinafter referred to as the “high-precision chassis region”), and a chassis region where others of the mechanisms are to be arranged satisfactorily with a relatively low precision (hereinafter referred to as the “high-strength chassis region”) In this case, the chassis is so shaped that the pair of side plate portions adjacent to each other at at least one corner included in the high-precision chassis region are separated from each other, and that the pair of side plate portions adjacent to each other at at least one corner included in the high-strength chassis region are joined to each other.
The structure wherein one pair of side plate portions are separated can be realized by cutting out a metal sheet blank in a shape including a flat plate portion and the two side plate portions as unfolded to the same plane as the flat plate portion, and thereafter bending the two side plate portions by press work. The structure wherein one pair of side plate portions are joined can be realized by subjecting the corresponding corner of the metal sheet blank to press work involving drawing.
In the process for making the mechanism chassis, at least one pair of side plate portions are separated in the high-precision chassis region, so that the residual stress resulting from the press work is mitigated at the separated portion, while the strain remaining after the press work can be corrected with a high precision in the same manner as in the prior art. This gives the high-precision chassis region a high degree of flatness. Consequently, when arranged in the high-precision region, the mechanisms of which a relatively high precision is required are capable of realizing an accurate operation.
On the other hand, the high-strength chassis region has a high structural strength since at least one pair of side plate portions are joined in this region, whereas this structure permits the press work to produce a residual stress to result in some strain. This strain is difficult to correct completely because of the high structural strength of the high-strength chassis region. However, no problem arises since the mechanisms of which a relatively low precision is required are arranged in the high-strength chassis region. The high structural strength rather imparts increased rigidity to the overall chassis, with the result that even if prepared from a metal sheet of smaller thickness than conventionally, the mechanism chassis is given a sufficient structural strength in its entirety.
For example, in the case of a mechanism chassis for mounting VCR mechanisms thereon, a high degree of flatness is required of a backward chassis region where the rotary head cylinder
2
and the capstan
5
are to be arranged. This region is therefore designed as the high-precision region. A forward chassis region where the pair of reel supports
3
,
4
are to be arranged need not have a very high precision, and is accordingly designed as the high-strength chassis region.
The mechanism chassis of the present invention has satisfactory flatness and high structural strength in its entirety, can nevertheless be prepared from a thinner metal sheet than conventionally and is therefore reduced in weight.
REFERENCES:
patent: 4930028 (1990-05-01), Kunimaru et al.
patent: 5099369 (1992-03-01), Kakuta et al.
patent: 5419629 (1995-05-01), Korinsky
patent: 5442502 (1995-08-01), Shimizu
patent: 5519270 (1996-05-01), Yamada et al.
patent: 5717540 (1998-02-01), Ishikawa et al.
patent: 5801898 (1998-09-01), Okuie et al.
patent: 5847485 (1998-12-01), Suzuki et al.
patent: 5870248 (1999-02-01), Akutsu et al.
patent: 5875068 (1999-02-01), Sawada
patent: 6172842 (2001-01-01), Satoh et al.
patent: 61-20248 (1986-01-01), None
patent: 61-20286 (1986-01-01), None
patent: 11-186750 (1999-07-01), None
Armstrong Westerman Hattori McLeland & Naughton LLP
Miller Brian E.
Sanyo Electric Co. Ltd
LandOfFree
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