Electricity: electrothermally or thermally actuated switches – Thermally actuated switches – Expansible or vaporizable fluid actuated
Reexamination Certificate
2003-04-16
2004-11-16
Vortman, Anatoly (Department: 2835)
Electricity: electrothermally or thermally actuated switches
Thermally actuated switches
Expansible or vaporizable fluid actuated
C337S320000, C337S312000, C337S306000
Reexamination Certificate
active
06819216
ABSTRACT:
FIELD OF THE INVENTION
The present invention relates to thermostats for controlling a temperature in a storage room of refrigerators.
BACKGROUND OF THE INVENTION
Thermostats are widely used to control a temperature in a storage room of refrigerators. Such a thermostat is disclosed in Japanese Utility Model Publication No. S56-2546. A conventional thermostat is described hereinafter with reference to
FIGS. 6 and 7
.
FIG. 6
shows a front view of the conventional thermostat, and
FIG. 7
shows a lateral view of the same thermostat. In
FIGS. 6 and 7
, housing
101
is made from metal plate undergone press working that forms the metal plate into one-piece housing. Housing
101
is formed of upper face
102
, two long side-faces
103
and one short side-face
104
.
Switch section
105
is placed such that it faces short side-face
104
of housing
101
. Bottom plate
106
faces upper face
102
. On upper face
102
, adjusting shaft
107
, cam
107
a
formed at the root of shaft
107
, and adjusting plate
108
displaced by cam
107
a
are provided.
Switch section
105
has a switch mechanism (not shown) inside housing
101
, and coupling terminals
105
a
,
105
b
protruding outward from housing
101
. Beneath bottom plate
106
bellows
109
is prepared, and it communicates with the inside of housing
101
, so that displacement of bellows
109
activates the switch mechanism of switch section
105
. Bellows
109
is filled with gas that is expanded or compressed in response to an atmospheric temperature.
Tube
110
extends from bellows
109
by a given length and communicates with the inside of bellows
109
, so that tube
110
is also filled with the gas.
The gas in tube
110
is expanded or compressed in response to the atmospheric temperature. An expansion prolongs bellows
109
, thereby operating the switch mechanism to close a circuit. A compression, on the contrary, shortens bellow
109
, thereby releasing the switch mechanism from the operation and opens the circuit.
Rotating shaft
107
by a given angle causes cam
107
a
to rotate by a given angle, so that adjusting plate
108
rotates along cam
107
a
to produce displacement. This displacement of adjusting plate
108
strengthens or weakens force of operating the switch mechanism. A balance between this operating force and working force of bellows
109
at expansion or compression can set a temperature at which the circuit opens or closes. Long side-face
103
has supporting hole
103
a
for supporting fulcrum
108
a
on which adjusting plate
108
rotates, and fulcrum
108
a
exposes itself outward.
Adjusting screw
111
is prepared for fine adjustment of the temperature set by the rotational position of adjusting shaft
107
. A user can rotate screw
111
with a driver via through-hole
104
a
punched on short side-face
104
.
However, since the foregoing conventional thermostat has fulcrum
108
a
, related to adjusting plate
108
, exposed from supporting hole
103
a
, a user is liable to touch fulcrum
108
a
with a finger when the user holds housing
101
in the hand, so that the set temperature tends to change.
Further, the foregoing conventional thermostat has adjusting screw
111
at an upper section of housing
101
, and switch section
105
is placed at a lower section of housing
101
, so that coupling terminals
105
a
,
105
b
protrude downward, which makes housing
101
unstable. In order to make housing stable, long side-face
103
or short side-face
104
should face downward, then a user looks at adjusting screw
111
laterally, which makes an adjustment difficult.
SUMMARY OF THE INVENTION
The present invention addresses the problems discussed above and aims to provide a thermostat that comprises the following element:
a housing;
a switch mechanism having contacts and accommodated in an outer shell;
a temperature sensing section which converts a volume change of gas being expanded or compressed in response to an atmospheric temperature into force for operating the switch mechanism;
a lever for opening or closing the contact by rotating itself on a first fulcrum with the force supplied from the temperature sensing section;
an adjusting plate engaged with the lever and rotating itself on a second fulcrum for increasing or decreasing the force necessary for rotating the lever; and
a cam shaft having a cam that rotates the adjusting plate.
The housing is placed outside a supporting wall that supports the first and the second fulcrums, and includes a wall that covers both the fulcrums.
REFERENCES:
patent: 2194533 (1940-03-01), Dyke
patent: 3185796 (1965-05-01), Mamiya et al.
patent: 3412357 (1968-11-01), Odashima
patent: 3636287 (1972-01-01), Jorgensen et al.
patent: 4388605 (1983-06-01), Machida et al.
patent: 4510480 (1985-04-01), Rossi et al.
patent: 4540860 (1985-09-01), Odashima et al.
patent: 4794363 (1988-12-01), Hirata et al.
patent: 6252492 (2001-06-01), Frank et al.
patent: 6307461 (2001-10-01), Frank et al.
patent: 6525641 (2003-02-01), Frank
patent: 56-2546 (1981-01-01), None
patent: 02195622 (1990-08-01), None
Kokubu Naotake
Nakajima Yoshihide
Onishi Ichiro
RatnerPrestia
Vortman Anatoly
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