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Патент USA US2120929

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June 14, 1938.
w. B. CLIFFORD
THERMOSTATIC UNIT
Filed March 18. 1935
JJ
M Q
2,120,929
2,120,929,
Patented June 14, 1938
‘ A UNITED
rice
PT
STATES
2,120,929
THERMOSTATIC UNIT
assignor to
Walter _B_. Clifford, Boston, Mass,
Boston, Mass, a
Cliii‘ord Manufacturingv 00.,
corporation of Delaware
5
Application March 18, 1935, Serial No. 11,564
»
3 Claims. (Cl. 297-3)
with the requirement of a minimum number of
The present invention relates to thermostatic
in the switch mechanism itself. A
units, and more particularly to self-contained parts
> With this and other objects in view, I have
units of this character designed for attachment devised the unit shown in sectional elevation in
to a switch, valve or the like which is to be con
the drawing, which embodies many desirable fea
trolled thermostatically.
. o
\
tures and which represents the preferred form
In the operation of electric refrigerators, oven
of such a self-contained unit.
controls and other units of this general char
In this embodiment of the invention as illus
acter, a thermostatic unit which comprises a
bellows with attached capillary to provide a
sealed expansible space responsiveto the “thermo
static ?uid contained therein_ has many desirable
attributes. The capillary at its end remote from
the bellows may or may not be provided with a
' bulb-shaped reservoir, and the bellows may or
1
may not be enclosed within a surrounding, hous
trated in the drawing, it will be noted. that the
assembly as a whole comprises essentially a cup- 1
like housing It, suf?ciently strong and rigid to
be in?exible, having-attached at its closed end
a capillary tube l2 which is provided at its end
remote from the cup with an enlarged bulb M. 15
A cup-like bellows unit It is received within the
housing It, and is connected to the housing at
ing. In either case, the operation of the unit is 'the open end through an integral and generally
the same. namely. the bellows is caused to ex ' radial ?ange l8 which is seated within a circum
pand‘and contract in re?ection of the tempera
ture within which the capillary, or more partic
20 ularly the bulb. is located. providing a remote
control and permitting the location of the switch
_ or valve which is connected with the bellows
‘ wherever it may be desired in the design of the
refrigerator‘, oven or 'the like.
.
1
25/ vFrequently these units, particularly if designed
for refrigerator work, are ?lled with a thermo
ferential recess 20 formecL adjacent the rim of
the housing.
The radial ?ange it may have an 20
outwardly and axially directed portion 22, which
causes the ?ange to conform generally to the
recess ‘in the housing. By properly bonding the
?ange to the housing, as by solder or otherwise,
the annular space between the bellows and hous
ing' is sealed, and in conjunction with the cap
25'
‘ illary and bulb presents an expansible chamber
static ?uid which develops a"substantial vapor of any desired length which may be filled with
pressure at room temperature, and the unit itself thermostatic ?uid.‘ 'As a rule, the ?uid employed
must be protected against distortion or over
is capable of developing a substantial vapor pres- ?
3 stressing of the bellows due to pressures which ' sure throughout the temperature range for which
may be encountered internally of the unit dur-. the unit is designed, and is completely evacu
ing manufacture, shipping and handling prior ated of air and all foreign materials before ?ll
' to its permanent installation in connection with, ing.‘ This is accomplished by connecting the
the switch or valve.
reduced extended end 30 of the bulb to a vacu
desirable that these units um
source, cokmpletely exhausting the interiorof
3? It is furthermore self-contained
in the sense‘ the unit, ?lling with the desired thermostatic
‘shall be completely
‘that not only theexpansible or contractible bel
?uid, generally in the form of a gas, and there
lows'with its operatingw member be capable of after pinching off the extended end at 32 and
ready attachmentrto the switch, but in addition
4Q the loading spring which opposes the vapor pres
" sure, if it can be embodied within ‘the thermo
static unit and forming a part thereof, effects a
marked saving in space .in the switch or valve
mechanism itself.
The purpose of the present invention is to de
sign a completely self-contained thermostatic
unit which is capable of withstanding whatever
abnormal temperatures it may encounter in ship
ment and‘handl'ing without over-stress of the
50 bellows wall, and which contains all of the oper
'40
sealing with solder or the like at 34.
During the ?lling of the unit and the main- '
tenance of a vacuum in the annular‘ space be
tween the bellows and housing, the inward move
mentof the movable end wall 36 of- the bellows
is limited by engagement of the depressed por-_
tion 38 with the adjacent portion of the housing~
wall. The open end of the housing I0 is pro- v
vided with a closure 40 of circular outline, seat
ed in the recess 20 above the bellows and con-'_ .
nected to the housing through the joint which
seals the bellows thereto. This transverse clo
sure member'is provided with a central opening,
ating appurtenances including the loading spring
has ‘threaded therein a spring abutment 42,
self-containedl'within the unit in such a manner' l[and
sustains the outward‘thrust, of a loading
as to permit ‘attachment of the unit directly to which
spring 44 interposed between the abutment and
, 55 the switch mechanism‘without modi?cation, and
2
2, 120,929
a spring seat 46 mounted on the movable end
wall of the bellows. Proper adjustment of the
abutment 42 serves to impart the necessary
spring load to oppose the vapor pressure gen
erated for moving the end wall of the bellows.
Outward movement of the end wall 36 is con
?ned and limited by a tubular stop member 48,
does it normally interfere with the sealing func
tion at room temperatures.
What‘ is claimed is:
-
-
1. A thermostatic unit comprising a cup-like
housing having an attaching ?ange at the rim, 5
a cup-like bellows received in the housing and
connected thereto adjacent the rim of the hous
ing to provide an annular sealed space there
10 a part of the closure 40, this stop member being’, between, thermostatic ?uid ?lling the space, the
bellows having a movable end wall, a closure
threaded internally and constitutingthe thread
member for the open end of the housing havinga
ed support for the abutment.
V
which in the illustrated embodiment of the in
vention actually projects inwardly from and is
It will be observed that with this construction
the limiting stop 48 is supported rigidly from the
15 housing, and forms a ?xed and de?nite limit to
control outward movement of the end wall, the
latter moving within limits controlled by the stop
48 and adjacent wall of the housing.
Mounted upon the end wall and projecting out
20 wardly beyond the housing is an operating pin 50,
which is welded to the end wall 'at its base with
out requiring piercing of the wall, and which is
appropriately shaped at its outer end to engage
the switch or the like to be operated. It will
25 be observed that with this construction the load
ing spring may be adjusted through manipula
tion of the abutment to apply any appropriate
load to the end wall in opposition to the vapor
pressure load after ?lling and sealing of the
30 unit. , Furthermore, in the normal relationship of
the parts, all of the operating parts of the unit
. are enclosed in a space encompassed by-the hous
ing l0 and the plane of the attaching ?ange 52,
this attaching ?ange being drilled or otherwise
35 to provide for attachment to the surface of a
switch housing or the like.
‘
The construction, due to its compact and self
contained characteristics, lends itself admirably
to convenient attachment to a simple form of
40 switch housing which does not require the usual
type of loading spring heretofore employed and
requiring a larger and more cumbersome form of
switch mechanism.
-
It is desirable to immerse the unit in a plating
45 bath or the like after completion, and to make.
this possible without likelihood of plating fluid
reaching the bellowsiolds and eventually caus
ing corrosion, the movable end wall is provided
in the circumferential recess 54 with a sealing
50 disk 56 of compressible and preferably non-me
tallic material, designed to engage with the lower
I arm of the stop tube 48 on the development ‘of
vapor pressure sumcient to move the end wall out
wardly. In this position any plating ?uid or the
.55 like which may enter into the spring chamber is
not allowed to pass beyond the interior of the
stop tube and outwardly intc; the bellows folds.
Inasmuch asysu?icient'vapor pressure is ordi
narily developed at room temperatures or higher,
60 to provide a tight seal particularly in the ele
vated temperature of the plating bath, no special
adjustment of the loading spring is required, nor
central tubular portion which projects length
wise of the bellows and interiorly thereof, the
tubular portion serving to limit outward move—
ment of the end wall, means for sealing the space 15
about the tubular projection upon outward move
ment of the end wall, an abutment adjustably sup
ported in the tubular portion of the closure, a
loading spring within the tubular extension and
interposed between the abutment and movable 20'
‘end wall, and an operating pin secured to the end
wall and extending within the tubular portion
lengthwise of the bellows and beyond the plane
ofthe attaching ?ange.
2. A thermostatic unit comprising a cup-like 25
housing, a bellows cup received within the housing '
and attached thereto at the open end to pro
vide a sealed annular space therebetween,,ther
mostatic ?uid ?lling the space, a movable end
wall for the bellows, a closure for the open end of 30
the housing having a tubular extension extending
inwardly therefrom within the bellows to‘ provide
a stop for limiting outward movement of the end
wall, a loading spring received within the tubu
lar extension, an adjustable abutment engaging
the outer end of the spring and threaded in the
tubular extension, andan operating member ex
tending lengthwise of the spring and projecting
outwardly beyond the closure.
‘
.
.
v3. A thermostatic unit comprising a cup-like 40'
‘housing having an attaching ?ange at the rim, a
bellows cup received within the housing having
a radial attaching ?ange connected to the how
ing adjacent the rim to provide a sealed annular
space therebetween, thermostatic ?uid ?lling the
space, a rigid'closure connected to vthe housing
beyond the‘ bellows and supporting the radial‘
?ange, the closure having a- tubular and inwardly
extending projection to form a hollow chamberv
centrally thereof, the projection at its inner end
serving as a stop to'limit outward movement of
the end wall, an operating pin connected to the
end wall extending lengthwise of the bellows to a
point beyond the rim of the housing, a loading
spring received in the chamber formed by the 55
extension and resisting outward movement of the
end wall, and an abutment adjustably connected
.to the closure and engaging the spring to sustain ‘
the thruster-the spring, the abutment having a
passage for the free movement of the operating
member therethrough.
'
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WAL'I'ER B. CLIFFORD?“
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