Joints and connections – Including frangible component
Reexamination Certificate
1999-11-17
2001-09-18
Kim, Harry C. (Department: 3629)
Joints and connections
Including frangible component
C403S282000, C403S365000
Reexamination Certificate
active
06290420
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
This invention relates to a connection structure of an electrical component such as a variable resistor.
2. Description of the Related Art
A connection structure of a conventional electrical component is described herein under with reference to
FIG. 6
to
FIG. 10
in which a variable resistor is exemplified.
A base plate
21
formed of a molded synthetic resin is flat and has a hole
21
a
at the center, and a U-shaped resistor (not shown in the drawing) and a circular collector (not shown in the drawing) are provided on the upper side of the base plate
21
.
Terminals
22
and
23
are embedded on the base plate
21
, the terminal
22
is connected to the collector and the terminals
23
are connected to the resistor.
A cover
24
formed of molded synthetic resin has a flat wall
24
a
, a side wall
24
b
which extends from the periphery of the flat wall
24
a
downward, a plurality of snaps
24
c
which extend downward from the bottom end of the side wall
24
b
, and a hole
24
d
formed at the center of the flat wall
24
.
The cover
24
covers the top side of the base plate
21
so as to cover the resistor and collector, and is fixed to the base plate
21
by snapping the snaps on the periphery of the base plate
21
.
The first connection member
25
consisting of polyacetal synthetic resin which constitutes a rotor has a sleeve
25
b
having a non-circular hole
25
a
and a plate
25
c
which extends radially from the sleeve
25
b
, and a moving contact
26
having contacts
26
a
and
26
b
is embedded on the connection member
25
.
The connection member
25
is inserted supportingly to the hole
21
a
of the base plate
21
and the hole
24
d
of the cover
24
, and attached rotatably to the base plate
21
and the cover
24
.
When the connection member
25
is attached, the contact
26
a
is brought into contact with the collector slidably and the contact
26
b
is brought into contact with the resistor slidably.
The second connection member
27
which constitutes a shaft consists of metal material or synthetic resin material, and has a non-circular end
27
a.
Because the first connection member
25
is formed of polyacetal synthetic resin, if the clearance between the hole
25
a
of the first connection member
25
and the end
27
a
of the second connection member
27
is zero, the end
27
a
is not inserted into the hole
25
a
, therefore a clearance K is provided between both members, and the end
27
a
is inserted into the hole
25
a
to connect the first connection member
25
to the second connection member
27
.
When the second member
27
, which is a shaft, is rotated, the first connection member
25
, which is a rotor, is rotated, and the contacts
26
a
and
26
b
of the moving contact
26
are slid on the collector and resistor respectively with the rotation to change the resistance value.
Next, a method for fabrication of the first connection member
25
is described with reference to
FIG. 10. A
metal mold
28
comprises an inner mold
28
a
provided at the center for forming the hole
25
a
of the first connection member
25
, and an outer mold
28
d
having a cavity
28
b
for forming the sleeve
25
b
and plate
25
c
and a gate
28
c
for injecting hot molten resin into the cavity
28
b
. Next, when molten polyacetal synthetic resin is injected into the cavity
28
b
from the gate
28
c
, polyacetal hot molten resin is jetted against the inner mold
28
a
and the stream is branched toward the arrow directions, the branched streams merge and are mixed at the position G located on the opposite side with the gate
28
c
, and then polyacetal synthetic resin is solidified and thus the molding of the first connection member
25
is completed.
Because polymer molecules of the polyacetal synthetic resin are entangled each other in molten state and solid state, when streams are merged at the position G on the opposite side with the gate
28
c
, the streams are mixed completely and form a molded product having no weld mark. Therefore, the sleeve
25
b
of the first connection member
25
exhibits little deformation, as the result, press fitting of the second connection member
27
into the sleeve
25
b
of the first connection member
25
having the structure as described above is difficult, and the first connection member
25
engages the second connection member with a play gap.
Because the first connection member
25
is formed of acetal synthetic resin, press fitting of the second connection member
27
into the first connection member
25
is difficult in the conventional connection structure of an electrical component, both members are connected with play and engaged with play.
The rotation of the second connection member
27
is transmitted to the first connection member
25
with play, and the rotation transmission is not correct.
SUMMARY OF THE INVENTION
In a first embodiment for solving the above-mentioned problem, the structure comprises the first connection member having a sleeve provided with a hole and the second connection member to be press-fitted into the hole, the first connecting member being formed of synthetic resin consisting of liquid crystalline polymer.
In a second embodiment, the sleeve has a weld mark formed in the insertion direction of the second connection member.
In a third embodiment, the first connection member constitutes a rotor and the second connection member constitutes a shaft.
REFERENCES:
patent: 4479106 (1984-10-01), Shimizu et al.
patent: 5148718 (1992-09-01), Kakuguchi et al.
patent: 5460035 (1995-10-01), Pfaffenberger
patent: 5494426 (1996-02-01), Ibar
patent: 6015523 (2000-01-01), Yumoto
patent: 6142677 (2000-11-01), Sato et al.
Alps Electric Co. ,Ltd.
Brinks Hofer Gilson & Lione
Kim Harry C.
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