Static structures (e.g. – buildings) – Composite prefabricated panel including adjunctive means – Sandwich or hollow with sheet-like facing members
Reexamination Certificate
2000-03-13
2002-12-24
Horton, Yvonne M. (Department: 3635)
Static structures (e.g., buildings)
Composite prefabricated panel including adjunctive means
Sandwich or hollow with sheet-like facing members
C052S630000, C052S707000, C052S783170, C052S783190, C052S793100, C052S794100, C029S458000, C029S525000, C156S066000
Reexamination Certificate
active
06497082
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to a sandwich panel used as a structural member of an artificial satellite, a space antenna, or the like, and a method of manufacturing the sandwich panel.
2. Description of the Related Art
Referring to
FIGS. 15 and 16
, a description will be given of the structure of a conventional sandwich panel and a method of assembling the same.
FIG. 15
is a diagram illustrating an example of a conventional sandwich panel fabricated by a most common manufacturing process. In addition, a sandwich panel shown in
FIG. 16
is the one shown in Japanese Patent Unexamined Publication No. 275930/1992. In
FIGS. 15 and 16
, reference numeral
2
denotes a facing member;
3
, a film-like adhesive agent;
4
, a coremember;
7
, an insert;
7
a
, an upper flange;
7
b
, a threaded portion;
7
c
, a lower flange;
8
, a filler;
9
, an adhesive agent;
10
, a fitting hole;
11
, an insert;
11
a
, a flange;
11
b
, a threaded portion;
12
, a through hole; and
13
, an escape. First, a description will be given of the function of the insert incorporated in the sandwich panel. In
FIGS. 15 and 16
, the inserts
7
and
11
have threaded holes in the threaded portions
7
b
and
11
b
. Some apparatus, though not illustrated, is generally mounted on the surface of the sandwich panel used as a structural member of a satellite. The insert serves as a threaded hole for mounting this apparatus and a grounding plate of the apparatus. Since the apparatus is generally mounted by a plurality of screws, a screw pitch must be secured with high accuracy. In addition, as can be seen from
FIG. 15
, the upper surface of the insert
7
is attached in such a manner as to be located at a somewhat sunken position from the facing member
2
. The purpose of this is to effect the radiation of the apparatus efficiently. Namely, by causing the apparatus and the facing member
2
to be brought into close contact with each other, the heat which is generated in the apparatus is transmitted to the facing member
2
, and the heat is introduced to a radiating portion by a heat pipe (not shown) incorporated in the sandwich panel. However, if the upper surface of the insert
7
projects above the facing member
2
, the close contact between the apparatus and the facing
2
is prevented.
Next, a description will be given of the method of manufacturing the sandwich panel shown in FIG.
15
. First, a pair of assemblies in each of which the film-like adhesive agent
3
is attached-to the facing member
2
are prepared, and the core member
4
is sandwiched by them. In this state, heat is applied from the outside while applying pressure to allow the adhesive agent
3
to cure. The fitting hole
10
is cut in the thus-prepared sandwich panel by end milling. The inside diameter of the fitting hole
10
is in a fitting relationship with the outside diameter of the upper flange
7
a
of the insert
7
, and serves to position the insert
7
.
Next, after the adhesive agent
9
is applied to the bottom of the fitting hole
10
, the height of the insert
7
is made capable of being positioned at a desired position by an unillustrated jig or the like. The insert
7
is then supplied, and the adhesive agent
9
is left to cure. After the curing of the adhesive agent
9
, the filler
8
is supplied through such as a hole (not shown) provided in the upper flange
7
a
of the insert
7
. When the filler
8
cures, the insert
7
and the core member
4
are firmly secured to each other. In a case where vehement vibrations are applied such as during the launching of the satellite, the apparatus on the sandwich panel also vibrates, so that a large pulling load is applied to the insert
7
. However, the reason that the sandwich panel is not broken during such a time is that the load is distributed since the pulling load acting on the insert
7
is transmitted to the core member
4
through the filler
8
.
Next, referring to
FIG. 16
, a description will be given of a structure and a manufacturing method which are different from those of the sandwich panel shown in FIG.
15
.
The insert
11
has the same function as that of the insert
7
shown in FIG.
15
. The insert
11
differs greatly from the insert
7
in that the insert
11
is bonded to the reverse side of the facing member
2
and that the filler
8
is not used. Namely, the major characteristic is that the heat is distributed since the apparatus mounted on the sandwich panel can be brought into close contact with the facing member
2
at a portion other than the through hole
12
through which the fixing screw is passed and that the pulling load applied to the insert
11
is transmitted to the facing member
2
through the upper flange
11
a having a large outside diameter.
Next, a description will be given of the method of manufacturing the sandwich panel shown in FIG.
16
. First, the through hole
12
is cut in the facing member
2
to which the insert
11
is attached. Subsequently, the insert
11
is bonded to the facing member
2
by some method. At this time, the hole
13
is provided in advance in the core member
4
in a separate step as a space for disposing the insert
11
on the inner side of the core member
4
(this step will be referred to as that of escape machining, and the hole as the escape). In an ensuing step, the core member
4
with the escape
13
machined therein is positioned and supplied onto the facing member
2
with the insert
11
bonded thereto and the film-like adhesive agent
3
, and the facing member
2
and the film-like adhesive agent
3
on the opposite side are supplied. In this state, if pressurization and heating are effected to cure the adhesive agent
3
, the sandwich panel incorporating the insert
11
is formed.
With the sandwich panel of the conventional structure shown in
FIG. 15
referred to above, not only is it necessary to effect assembly by using a jig or the like while exercising caution so that the upper surface of the insert does not project from the upper surface of the facing member and does not become excessively depressed, but also it is necessary to pour the filler so that voids will not be created inside. For this reason, there has been a problem in that the insert attaching operation becomes a difficult and time-consuming operation. Further, the hole for attaching the insert must be machined in the sandwich panel after the adhesive agent is cured; however, there has been a problem in that an extreme risk is entailed in the provision of mechanical processing in such a sandwich panel that a heat pipe, for instance, is embedded in its interior as with a heat pipe panel used in a structural member of a satellite. Namely, if the heat pipe becomes damaged due to poor workmanship in the hole machining, ammonia which is a deleterious substance jets out.
In addition, the insert used in the conventional structure required the lower flange portion for retaining the solidified filler to sufficiently ensure pulling strength, the upper flange for fitting to the fitting hole, and the small diameter portion which provides the space for the filler to enter and is used to reduce the weight of the insert itself. For this reason, the component shape becomes that with a large cutting allowance, so that there has been a problem in that the unit cost of the component becomes high.
Meanwhile, with the sandwich panel of the conventional structure shown in
FIG. 16
, not only is it necessary to effect hole cutting or escape machining before the sandwiching of both the facing member and the core member, but also it is necessary to accurately position the facing member with the insert bonded thereto and the core member provided with the escape machining. Therefore, there has been a problem in that productivity is poor. Further, since a lateral force is applied to the core in the escape machining of only the core member before sandwiching the facing member and the core member, there has been a problem in that the core is liable to become deformed, and the productivity is fur
Kawasaki Masakatsu
Kunugi Toshiaki
Okamura Masamitsu
Takayama Hiroshi
Toyoda Norihiko
Burns Doane , Swecker, Mathis LLP
Horton Yvonne M.
Mitsubishi Denki & Kabushiki Kaisha
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