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Патент USA US2116909

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May 10,> `1938.`
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10, 1938.
Filed Jan. 3U, 19.34
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>May 10, 1938.
Filed Jan. BO, 1954
8 Sheets-Sheet 5
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May l0, 1938.
G, (_:~ PEARCE
Filed Jan. 30, 1934 ‘
8 sheets-sheet 4
May 10, 1938.
l Filed Jan. 30, 1954
8 Sheets-Sheet 5
May 10, 1938.
Filed Jan. 30, 1934
8 Sheets-Sheet 6
May 10, 1938.
- 2,116,909
Filed Jan. 30, 1934
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May 1o, 193s;
G. C, ,DE/WCE>
Filed Jan. 30, 1954
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_Patented May 1o,f 193su ‘
-George C.v Pearce, Dayton, ûhio,
or ’to Gen
eral Motors Corporation, Dayton, 0h10, a cor
poration of Delaware
Application January 3%,î 1934„ Serial No. 3108.994
4 Claims. iCl. 20o-31E;
. is a sectional ‘View along the line @mii ci
This invention relates to refrigerating appa-1
ratus and more particularly to pressure operated
s a sectional View aiong the
refrigerator control switches.
'im-‘i in’
It is an object of my invention to provide an
5 improved switch mechanism for refrigerating ap
paratus, said switch mechanism being provided.
with a temperature adjusting means` providing
continuous cycling above and below freezing;
temperature, and with a defrosting mechanism
_i0 which is automatically rendered ineil'ective when
the proper temperature is reached, together with
an improved overload means for the electric cirs
cuit in which a iinger manipulating‘device server.’
both for shutting the refrigerator on and oi! as
i5 well as for resetting the overload device and serv@
lng as an indicating means for indicating the
condition of the` overload means.
y, It is anptther object of my invention to provide
a switch for a refrigerating system provided with,
20 parts that may be easily manufactured, assernn
bled, and repaired, and so arranged that the
Fia”. ‘
device and ‘the i
es a diagrammatic View or” a reirîgerat» .
ing system showing” diagmliimeïleolly "the Elelîoli,
the 'terminal looX. the vlooi“ Switch. the door light? l5
erì? ‘the electrical eírelììÈS;
Fig. 'il is a sectional View showing the sonnen#u
‘tion between a 'terminal
the terminal nog and
a set of contacts in the switch;
is a diagrammatic View of a reirigerat- .5G
ing system illustrating a modification ci my in- `
manually manipulatable control devices and the
indices therefor may be symmetrically arranged.
It is another object‘of my invention to provide
‘.¿5 an improved switch wherein a terminal/box is
directly connected with the switch but which prevents ready access to the switch mechanism while
at the same time it provides easy access to the
terminal connection of the switch and provides
Fis» 13 is a top View with the Cover removed ci
the refrigerator Switch Shown in Fig. 12;
Flg- 1418 a Sectional View along the line lil-J4 g5
of F18’. 13;
2 F18- 15 is a Sectional View along the line l5--~i 5
of F18. 13;
F18- 16 1S a Sectional View along the line lG--lß
30 a place for a direct current adapter as well as
0f P18113;
additional terminals for connection to the other
accessories such as a door switch and light.
Fis. 171s a Sectional view along the line Il-,il
of Fig. 13;
Further objects and advantages of the present f F18'- 18 1S a Sectional View elong'the lino l8-l8
invention will be apparent from the following de- of Fig. 13;
35 scription, reference being had to the accompanyF18- 19 1S o Sectional View along the line |9-l9 35
ving drawings,- wherein. a preferred form of thepresent invention is clearly shown.
In the drawings:
` Fig. 20 is a sectional view along the line 2li-10
, -of Fig. 19;
Fig. 1 is a top view of one form of my improved
40 switch with the terminal box removed;
Fig. 2 is a sectional view along the line 2_2 of
Fig. 3;
of F18’- 14;
Fig. 3 is a sectional vièw along the line l-I of
Fig. 1;
Fig. 4 is a sectional view of the 'right hand
portion of Fig. 3, taken upon a line corresponding
. to the portion of the section line 2-2 upon the
-right side of Fig. 3, and showing the thermal
overload means and ratchet wheel in the position
nl50 it assumes after being tripped by an overload in
, terminal connections in the top cover; and
of Fig, 19.
Referring to the drawings and more particu
larly to Fig. 10, there is shown a refrigerating sys
tem comprising a compressor 30 for compressing 45
the refrigerant and for forwarding the com
vpressed refrigerant to a condenser 3| where the
compressed refrigerant is condensed and collect
ed in a receiver I2.
From the receiver 32 the
liquid refrigerant iS forwarded throußh‘e Supply 50
conduit y33 to an expansion valve or other suit
able restricting means 34 which controls the sup
--diiïering in that it shows the mechanism thermal
ply of liquid refrigerant to an evaporator 35 lo
, overload mechanism after being manually tripped
55 to open the electric circuit; `
Fis. 22 isa sectional view 'along theline 22-22
the electric circuit;
Fig. 5 is a sectional View similar to Eig, 4 but
11115.21 iS o View Showing a fragment of the
cated within the food compartment of the re
frigerator 36 where the evaporator absorbs‘heat
causing the liquid refrigerant. to vaporiae and he
returned to the compressor
The compressor
is driven by an electric motor 3l under the
oi athe
Sil in heat exchange
rEhe thermostat 38 is connected by a tube 3Q to
the pressure responsive snap acting switch means
/l-Q having a set of switch contacts fl which are
connesl d to the terminals ft2 and
located in
fiinal box [lil shown in
9. Í‘îhe ter
connected by an electrical conductor
minal „1
5 'to one oi the lead-ins of the motor, while the
terminal S3 has one electrical conductor «to lead
to a source of electric energy, while another
'l conductor di leads from the terminal
refrigerator light »i8 located within
compartment of the cabinet
is also connected by
m" e door
electrical con
the "ri-‘nt side of the escutcheon plate 'lil in
a symmetrical arrangement with the lrnob ‘l’
and the manipulating device
, there
vided a rectangular aperture ‘lll through winch
projects a ringer manipulating and indicating de
vice d@ winch cooperates with ‘the desig ation
above Lîreeaing
and after
order Yto per'nì
ture limit is reached s
be reto.
deirosting, this device
' effective position, thus permitting th
ing system to resume normal opera»
now more particular
there is shown at the rigT .t side or” r‘
open at the top (as viewed in „
box :3o. rEhe terminal 5@ is also connected by an
electrical conductor
to a door switch
of a suitable structural insulat
is operated by
as hard rubber or a phenol condeLsation in.
such as “Bakelite”,
stened to the bof
opening and closing oi the
rei igerator cabinet door so as to cause the light
lee lit when the door is open. The door
is also connected by an electrical con
ductor ce to a terminal iid located. in the terminal
rivets C@ is a braclret of;
" l'
which supports the leí‘t side o
ni in as viewed in `
tremities of this bracket by
iected to t
screws ik.
' This
terminal to the
is also
E_-shaped bracket «SSI which si j
which connects the second lead-in oi the elec
conductors :il and ¿lâ are grouped together within
an insulating covering @d which leads -from the
terminal box ¿lf3 to the door light Cil. The electri
connected at its lower end to tde tube
leads to the thermostat bulb Sill located
food compartment. r)The lower
ot the lc
is fastened to the L--shaped bellows suppo‘ ing
bracket E@ by a nut di. in order to prevent ex
cessive expansion oí the bellows
there is pro
vided an inverted L-shaped fiat metal stop mem
ber 92 which is provided with projections llt at
one end which extend through slots @il in. the bel
lows supporting member il@ while the other end,
as best shown in Fig. 8, is provided with an aper
30 'trical motor ‘dl to a side of the supply line.
cal conductors d5, fili, and
are grouped together
insulating covering @l which leads
from the terminal box to the electric motor 3l
and the supply circuit. »The electrical conductors
are grouped together within an insulat
ing covering
which leads from the terminal box
to the door switch 5l.
rilse 'terminal box [ld rests upon »the frame
extending across the top of the cabi
net and is fastened thereto by suitable screws G0.
The terminal box ¿ld is provided with a removable
ture or slot Q5 which receives a tongue @o through
which extends a cotter pin @l for holding the bel
lows stop in place.
A portion QQ oí the bracket
extends down
cover the
is fastened
box there
is provided
by a screw
"wardly and is provided with a tongue lll@ which
extends through an aperture lill having beveled
side walls which form lrniie edges at one of the
tions iill which divide the various terminals from
each other. Additional space is provided adja
surfaces of a bellows `follower l0@ formed of heavy `
sheet steel or brass. rFhis bellows follower E03 is
cent the terminals d2 and d3 to receive a direct
50 current adapter it one is required. Resting with
in a notch in the frame member
- beneath the terminal box is the switch mecha
nism. This switch mechanism is connected to
the terminal box Lid and to the terminals d2 and.
43 by screws 00 and 69 which extend through the
terminals 42 and ¿13 and are threaded into the
brackets ‘lli and ‘ll of the switch mechanism. A
third screw 'l2 extends from the terminal box
and is threaded into an ear ‘i3 formed on the
60 framework of the switch mechanism.
Upon the front of the cabinet immediately in
front of the switch mechanism there is provided
an escutcheon plate 'M provided with an indi
cating knob 'l5 having an arrow cooperating with
65 the dial ‘lli formed on the escutcheon plate in
order to provide manipulating and indicating
means for temperature regulation. At the left
side of the escutcheon plate there is provided a
rectangular aperture Tl having the finger manip
70 ulating device 'I8 projecting therefrom which co
operates with the indications “On” and “Off” on
the escutcheon plate in order to indicate the con
dition or the overload means as to whether the
overload means is in closed or open circuit posi
75 tion to turn the refrígerating system. 0n or 0d.
held in place by a cotter pin mi which extends
through the tongue U00. The bellows follower |03
is provided with a depression in one side which
receives a conical pin H05 which extends from the
movable end oi’ the bellows 90.
At one side, the bellows follower l03 is pro
vided with an ear il'lG extending at right angles
which is connected to a tension regulating spring
lill. This tension regulating spring is connected
at its lower end to a transverse lever |08, better
shown in Fig. 8, which is pivoted upon a pin
H09 at its intermediate point to the bracket 08.
The other end of the lever |08 is pinned to the
member H0 which is threaded upon an adjust
ing screw || l provided with a splined head H2
upon which the temperature regulating knob 15
is mounted. By turning the temperature regu
lating knob, the tension of the spring |01 is varied
in order to control and vary the expansion of
the bellows 90.
By this arrangement the size
or" the regulating screw and the spring may be
made small since the use of the lever |08 per 70
mits of considerable variation in travel between
the member ||0 and the lower end of the spring
l 01. This arrangement also avoids the binding
action found in most other arrangements for
temperature adjustments.
The bellows follower |02 is also provided with
`tongue |42 which normally is adapted to engage
a hard rubber or “Bakelite” insulating arm or
a shoulder upon the overload contact lever |24.
This slide bar |25 is also provided with a sec
extension ||3 molded thereon which insulat‘es
the bellows and the bellows follower from the
5 switch mechanism and which is provided at its
extrem/ity with a pair of V-shaped notches ||4
which receive the knife edges ||5 formed upon
the legs of a `U-s‘haped secondary lever `| I5 which
formsa, part of a double toggle snap acting
l0 mechanism. 'I'he U-shaped secondary lever is
provided at the opposite or closed end with a
T-shaped member ||1 which extends through a
/slot in the end portion of the U-shaped member
.and is provided with an eyelet ||8 to which is
15 A connected the tension coil spring ||9. The other
I end of this tension coil spring is connected t0
an upstanding portion |20 of a contact member
|2| of irregular shape which is pivoted upon
the pin |22 to a bracket |22 riveted to the wall
20 of the box 25. This contact lever is also provided
ond bent-up lip or tongue |42 which extends in
the opposite direction. When it is desired to
shut off the refrigerator the overload finger ma
nipulator 12 is moved to the left as viewed in
Figs. l and 2, thus moving to the right a hook
shaped slide bar |44 as shown in Fig. 5 so that
a cam |45 on its bottom edge engages the upper 10
surface of the lip |42 so as to move the free
end of the slide bar |25 downwardly to disengage
the lip |42 from the overload contact lever |24.
This hook-shaped slide bar | 44 is yieldingly urged
to the left by the tension coil spring |45 in order
to hold it against the lower projecting portion
|41 ‘of the iinger manipulator 12. The finger
‘ manipulator 18 is pivoted upon the pin |48 to
a Wall of the box 85.
In order to reset the overload means there is 20
provided a reversed L-shaped lever |49 which is
with integral stop portions |24 and |25 which
limit the movement of _the closed end of they pinned to the lower projection |41 of the finger
U-shaped secondary lever H5. 'I'he contact manipulator 18. This lever |49 is yieldingly urged `
lever |2| also has another arm |22 which car
in a counterclockwise direction about the pin con
25 jries by- a swivel pin arrangement a contact bar
|21 which bridges the contacts 4| in order to
complete the electric circuit.
As stated before, the -contact 4| nearest the
open side'of the box 25 is provided with a thread
nection by a light tension spring |50. The free 25
end of this lever is provided with a nose which
'engages a lip or tongue |5| which is struck out
from the overload contact lever |24. When the
' 30 ed bracket 1| for connection with the screw 52
viewed in Figs. 1, 2, 4, and 5, the nose of the lever 30
|49 engages the inclinedsurface of the tongue |5|
which forces its free end upwardly into engage
ment with the laterally extending insulating
member |52 which extends from a portion of the
main contact lever |2|. This engagement moves
the main switch contact bar |21 to open circuit
position during 'the time at which resetting oper
ation takes place. In addition to. engaging the
insulating member |52, the link |48 also moves
the @verload contact lever |24 to its vertical posi -40
tion as viewed in Figs.- l and 2. This permits the
tongue |42 >oi’ the slide bar |25 to again engage
its shoulder upon the overload contact lever |24
if it has been in the position shown in Fig. 5. If
the overload mechanism has been in the position
shown in Fig. 4, which it assumes when tripped
by- an overload current, the overload contact lever
| 24 will engage the turned-up lip |52 at the
adjacent end of the bar |22 and pull the bar to
extending from the terminal 42 and the terminal
' box 44 and in this way electrical energy is sup
plied to these contacts. Extending from the
opposite contact 4| is a heater coil |22 which
35 extends around a pin |29 having a ratchet wheel
|20 fastenedthereto by a fusible material, such
as solder.
This pin `.|29 is provided withi a
threaded portion whicli passes through the wall
of the box 25 and is threaded into the nut |2|
40 seated in the recess in the 'opposite side of thel
bottom wall of the box 25. 'I'he otherend of the
heater .coil |28 is connected to one of a set
of overload contacts |22, while the other contact
of this set is connected to the threaded bracket
l 45 12 which -is connected by the 'screw 29 to the
terminal 42 in the terminal box 44.d
'I'he contacts |22 are adapted to be bridged by
the overload contact bar |22 which‘is connected
by a pin and springy connection to the lower end
50 of an'overload lever |24 pivoted on a pin |25
/fixed in the bottom wail of the box 25.` This
overload lever |24 is normally held in a ver
tical position such ‘as that shown in Figs. 1 and
2 by a slide bar |22 which extends through a
finger manipulator 19 is moved to the right, as ,
the left as» viewed in Fig. 4 so as -to permit the 50
leaf spring |40 to again engage the ratchet wheel
|22 as yshown in Fig. 2.. By moving the main
switch contact bar |21 to open position during the
resetting operation, forcible operation of the re
55 slot in the lower end of an arm |21 of a bracket ` frigerating apparatus under overload conditions
|22 and which has its other end guided by the by holding the finger manipulator in resetting po
arm |29 at the oppositev side of the bracket |22. sition at this time is -prevented.
The bottom of the lever or link |49 is provide
This slide bar is provided on its bottom side with
a light leaf spring member „|42 which engages ` with a locking shoulder |15 which is adapted to
60 the ratchet-wheel |20 in order to prevent the engage the arm |29 of the bracket |28 upon which 60
overload rcontact lever |24 from moving to open the link |49- normally rests by gravity in order
circuit position which -isv illustrated in Fig. 4. to prevent anyone from opening the main switch
'I'he overload contact lever"|24 is yieldingly urged contacts 4| and |21 by moving the finger manip
to open circuit position by the tension spring 14| ulator to‘resetting position. In vthe normal reset
. 65 which extends from the overload contact lever
|24 tosthe arm |21; When an excessive elec
trical current passes through the heater coil |22
for a sufficient length of time the pin |29 is
heated suiiiciently to melt the fusible binder
ting opefrationythis shoulder | 15 is not engaged 65.
because the free end of the lever or link I 49 is
raised by the camming surface of the tongue |51`
thus causing the shoulder |15 to clear the bottom
lportion'of the slot in the arm |29 of the bracket
70 thereby permitting the ratchet wheel |22 to turn, |22 through which extends the link |49. After
thus releasing the leaf spring |40 and the slide the resetting operation is completed, the free end
bar |25 in order to permit the overload contact of the link |49 is out of contact with the camming
lever |22 to move to open circuit position under surface |5|_ and rests by gravity upon the bottom
the tension of the overload spring |4|. The_ of the slot in the arm |29. Thus, after resetting,
75 slide bar> |22 is provided with bent-up lip or any movement of the link |49 toward the cam
ming surface lill will be stopped by the engagement oi' the shoulder H5 with the portion of the
arm i351) below the slot. 'By preventing the con
tact of the end o1? the link i559 with the camini-ng
at this time the opening of the main
contacts which is depend-ent upon the coaction
oi` the end oí the link
with the camming
2Gb, such as a generator or a supply line
electrical conductor ‘Zili connected to
a contact
wh’ch cooperates with a lever iìi’f‘
pivoted at ílilíl
provided v th a pair of
mi ‘l
which cooperate with the contact
. a second contact
Connected to the
' v 're îfîû'i' which is adapted
~ 'when an ov
ater wire "
ning and closing
adjusted. by the
s ‘
the iront wall of
nberat its which
lower exten
" movement oi this main con.
t leaí s
g ibi' engages the
on 'he hexagonal portion of the diíerential
screw iii@ in order to prevent unintended move
4ereoií. '3y so doing, the closing pressure
and temperature of ‘the main Switch contacts is
tends to a starting winding L.;
varied independently oi the temperature regulat
sealed unit
ing or range adjusting means.
ln order to provide' means for deírosting the
„.„icli is connects _
` contacts
the contacts EEE, an eectilcal conductor
From the electrical. conductor
2M extends an electrical conductor 225i ‘which
connects to an electi'omagnet
which operates
refrigerator, the defrosting finger manipulator
upon an armature arm
0@ is pivoted to an ear lli@ formed at one end of
the bracket Sill. Extending from one side of this
tracted is adapted to pivot about. the pivot point
'finger manipulator
is a threaded pin itl which
moves bodily with the finger manipulator S0. The
threaded pin itl is surrounded by a compression
type coil spring MS2 which is held between a
splined adjusting nut M33 threaded upon the pin
Mii and spring follower l ¿i which is slidably
mounted upon the free unthreaded end portion
of the pin itl and which presses against knife
edges formed upon the free end portion of a toggle
link |105 pivoted by means of a pin lb@ to a toggle
supporting bracket E01 riveted to a portion of the
bracket 00.
This toggle link has bent portions
4(1) which receive a roller i‘itl which ís pinned to this
toggle link |105. @is roller is adapted to bear
upon a projecting portion it@ of -the bellows iol
lower i03 when the iinger manipulator 00 is moved
to defrosting position. When the finger manip
ulator 80 is moved to defrosting position, this
compression toggle link mechanism exerts an»
additional resilient pressure upon the bellows
follower |03 which opposes the expansion of the
bellows 90 and which thereby requires an addi
50 tional or higher pressure within the bellows and
the thermostat bulb 38 and, consequently, a higher
temperature of the thermostat bulb 38 and the
evaporator 35 before the main switch contacts
will be moved to closed circuit position to enable
55 the refrigerating apparatus to resume operation.
When this required high pressure and temper
ature is reached the upward movement of the
bellows follower |03 will also move the roller |68
and the toggle link |65 upwardly across the dead
60 center position so that it returns to its upper in
active position in which the roller |68 is out of
the path of the normal movement of the bellows
follower |03 and rests against a portion of the
bracket 98. In this way, this snap acting defrost
65 ing mechanism is returned automatically to inac
tive or ineiîective position upon completion oi a
defrosting cycle. If it is desired to discontinue a
defrosting cycle at any time during the cycle, the
finger manipulator 80 can be moved to ineffective
position merely by moving the finger manipulator
to the left as viewed in Figs. 1, 2, and 3.
In Figs. 12 to 22, a modification of my invention
is shown.
Referring now more particularly to Fig. 12,
there is disclosed dlagrammatically a source of
which when at
‘223 to close the circuit to the contacts îïí‘ii. The
electromagnet 221i is also connected to an elec
trical conductor 2
one end of which leads to
the running win. ng ‘"“li‘i located. within the
sealed unit 2l@ and for
a part of an electric
motor 226.ì
`Ílîl’ie electrical conductor
i is also connected
to a stationary contact 22'?! v sich cooperates with
the movable contact 252 fixed to the U-shapecî. 35
bimetal member 2li.
other ends oí the
running winding
and the starting winding
2i@a are
switchby an located
a cooling
unit or evaporating means
within the i‘ood
compartment 23H of a refrigerator. This con
trol switch 220 is operated by a thermostatic
bulb 232 located in contact with the bottom of
the evaporating means 230.
The cooling unit 230 absorbs heat from the
food compartment 23| and vaporizes the refrig
erant which is withdrawn from the cooling unit
through a suction line 233 by a compressor 234
located within the sealed unit 2|9 and directly
connected to the electric motor 226. The com 50
pressor 234 compresses the refrigerant and for
wards the compressed refrigerant to a condenser
235 Where the compressed refrigerant is liqueñed
and forwarded through a supply conduit 336
under the control of a suitable restrictor 331 to
the cooling unit 230.
When refrigeration is required, the thermo
static bulb 232 becomes sufliciently warm to cause
the control switch 229 to close, thus closing the
electric circuit and permitting a heavy surge
current to flow from the source of supply 200
through the electrical conductor 20| and from
the contact 20`2 through the contacts 205, and
the lever 204 to the contact 206, through the
heater 201, and the U-shaped bimetal member
2|| and through the electrical conductor 2 I4 and
the conductor 220 through the electromagnet 22|
and the electrical conductor 224 as well as
through the running winding 225, the electrical
conductor 228, the control switch 229, to the 70
source of supply. This surge current is insum
cient to cause the overload to heater'20‘l to open
the contacts 202 and 206 but is sufficient to cause
the electromagnet 22| to attract the armature
222 to close the circuit to the contacts 2|6 in order
to permit electric energy to ilow through the elec
trical conductor 2|5, contacts '2|6, and the con
ductor 2|1 to the starting Winding 2|8. By per
.mitting the iiow of electric energy through start
ing winding and running winding, the electric
motor 226 will be started.
This abnormal surge current causes heating
within the U-shaped bimetal strip 2|| which
after suiiicient heating moves to close the con
10 tacts 2 I2 and 221. This provides a shunt around
the electromagnet 22| and weakens the attrac
tion between the electromagnet and its armature
222, thus permitting the armature 222 to drop
and to open the starting winding circuit at the
contacts 2|6 thereby connecting the off supply
of electric energy to the starting winding 2|8.
The heating action of the electric current
through the leg 2|0 of the U-shaped bimetal
member 2|| is insufilcient to maintain the con
20 tacts 2|2 and 221 in closed position and these
contacts open, thus causing the current to the
running winding to ~flow through the leg 2|3 to
conductor 2|4 and the conductor 226 through
the electric magnet 22| to the starting winding
25 225. However, the amount of current passing
through the electromagnet 22| and the running
winding 225 is insuiilcient to cause attraction of
the armature 222. The circuit thus operates
under this condition until the thermostat 232 be
30 comes suiiiciently cold to cause the control
switch to be opened to open the electric circuit.
This permits the U-shaped bimetal member 2||
to cool and to again` assume starting position.
Instead of being connected in the circuit as
35 shown in Fig. 12, the entire overload means may
be placed in series with the electric conductor
224 and the running winding 225 where the over
load means may be made more sensitive to over
loads during the running period of the driving
40 motor and not be subject to starting winding
In this way more sensitive overload
protection may be provided.
Referring now more particularly to Figs. 13 t0
22 inclusive, there is shown a more complete em
.45 bodiment of the Acontrol switch 228. The control
switch 229 is provided with a lower housing 238
and an upper housing or cover 236, each of which
is‘made of a suitable'structural insulating ma-'
terial, such as hard rubber. 'I'he housing is sup
50 ported upon a cross strip 231 extending i’rom one
side to the other of the cooling unit 238. A screw
v238 fastens the housing to this cross strip 231 by
means of a nut 239 which fastens the lower hous
ing to the cross strip and an upper knurled nut
55 248 which fastens the upper housing 236 to the
lower housing 235 and the cross strip 231.
Fastened to the lower housing 238 by screws 24|
and 242 is abracket 243 which is connected to an
L-shaped bellows'support member 244 by the
60 screws 245.
A metal bellows 248 is fastened to
this bellows support member by a nut 241 and is
connected to the thermostat bulb 2_32‘ by a tube
248. The bellows 248 is protected from', excessive
expansionV by an inverted L-shaped ñat metal
65 stop member 256 which is provided with prongs
28| at one end which engage slots in the L-shaped
bellows supporting member 244, while the other
end is provided with an aperture or slot which
receives a tongue 282 provided with a cotter pin
70 263 for fastening the bellows stop to the bellows
supporting member 244.
The metal bellows 248 is provided at its upper
end with a. conical projection 288 which engages
a recess in a bellows follower- 288 which is pro
75 vided with an aperture which receives a tongue
251 provided with a cotter pin 258 for pivotally
fastening the bellows follower to the projection
of the bracket 243. Upon the freely movable end
of the bellows follower 256 is an insulating arm
or extension 259 which is provided with a pair
of V-shaped notches 260 which receive a pair of
knife edges formed upon the end of the leg of the
U-shaped secondary lever 26| which forms a part
of a double toggle snap acting mechanism.
secondary lever is provided with a T-shaped pin 10
262 which extends through an aperture in the
closed end of the secondary lever and is provided
with an eyelet 263 to which is connected a ten
sion-like toggle spring 264 having its other end
connected to a projection 265 which extends up
between the parts of the insulating arm 259. The
projection 265 is struck up from a contact lever
266 which is pivoted at 261 to the lower housing
235. This contact lever is provided with stop
portions 268 and 269 as well as an extension 210 20
which is pivotally connected to contact bar 21|
which when in closed position serves to bridge a
set of contacts 213 which are fastened to the
lower housing 235.
The contact lever 266 is also provided with a 25
second extension 215 formed of an insulating ma
terial which is adapted to contact with a differen
tial adjusting screw 216 which is provided with a
hexagonal portion 211 cooperating with a light
leaf spring 218 for preventing evaporation from 30
altering the differential adjustment and causing
the differential screw 218 to be turned thereby.
This differential screw 218 ~ limits the opening
movement of the contact lever 266 and thereby
varies the differential between the opening and 35
closing of the switch contacts.
A range adjustment is also provided. The bel
lows follower 256 is provided with an ear 288 to
which is connected a tension spring 28| having
its lower end connected to a lever 282 which is
pivoted at its opposite end by a screw 283 to the
bracket 243. At an intermediate point the lever
282 is provided with a pin 284 which connects the
lever to an adjusting screw 285 provided with a
ilange nut 286 at its upper end which may be em 45
ployed to raise or lower the lever 282 in order to
vary the tension upon the spring 28| in order to
control and regulate the expansion oi’ the metal
bellows 246.
The switch is also provided- with a defrosting
mechanism which is pivoted upon the screw 24|.
This defrosting mechanism comprises a member
288 pivoted upon the screw 24| yariel having a
threaded extending portion provided with an ad
justing nut 288 which bears against one end of a.
compressing toggle spring 288 which surrounds
the threaded extending portion. The other 'end
of the toggle compression spring 288 cooperates
with the toggle link 28| which is pivoted by s pin
282-to a bracket 283 which is riveted to the brack
et 243.` This toggle link 28|‘is provided with a
roller 284 which is adapted to bear upon the bel
lows follower 288 when in its effective or actuat
ing position as shown in Fig. 19. This snap acting
mechanism through the roller 284 interposes an 05
additional resistance to the expansion of the
metal bellows 248 and requires a sumciently high
temperature, such as 40° F. to permit defrosting
of the evaporator before sumcient pressure will
be produced in the bellows 246 to overcome this 70
additional resistance and move the contact bar
21| to closed circuit position. In so doing, the
bellows ~follower moves upwardly thereby moving
the roller 284 and the snap acting mechanism up
wardly to inactive position wherein the roller re- f
mains ont ot the path of movement of the bellows
follower 256. The upward movement of tl’ie tog
gle linl; is stopped by the bracket 2533.
The snap acting defrosting mechanism is there
fore automatically turned off when the proper
-' temperature is reached. However, manual rneans
in the form of a linlï
is connected to the enm
tension of the member 2&8 and tlie toggle lint", 29E
at the end ci the compression spring 2Q@ i; order
ll) to initiate a deirosting cycle. This lint.:
provided with
which extends to
the iront of tbe cooling unit. l'n order ‘to initiate
a defrosting cycle this extension 29B is pushed
rearwardly, thus moving 'the defrosti'ig incolla
nism into its position with the roller
upon the bellows follower
any time bea
fore completion ol? the detre-sting cycle it is desired
to resume normal operation immediately, the en»
tension 296 may be pulled out to remove the roller
20 2Q@ 'from the patti oi the bellows follower
to move the deirosting mechanism to retracted
position in order to permit the refrigerating sys
tem to resume normal operation immediately.
The top cover 238 is provided with terminals
298 and
to which are connected the electrical
conductor 228 and the electrical conductor Sil@
which lead respectively to the electric motor and
the source of supply. These-terminals 298 and
29S? are provided with spring portions which are
30 adapted to engage extensions Sill extending from
the switch contacts Zilli. in this way a con
venient connection is provided.
While the form of embodiment of the invention
as herein disclosed, constitutes a preferred form,
it is to loe understood that other forms might be
adopted, all coming within the scope of the claims
which follow.
What is claimed is as follows:
l. A switch including means responsive to a
40 predetermined ñow of electric energy through an
electric circuit for opening the electric circuit,
setting means from open position to closed posi~
tion for preventing the movement oi tl'ie resetting
to closed
reset. position after the resetting
2. ./«i switch including means responsive to a 5
electric circuit flow
for oí
`1esetting means for said :first mentioned nl
1 r moving the ñrst mentioned
circui' liosition from open "osi
o_ ening the electra“l ci'.'
operation, and locltinL
ment oi the resetti.
after being reset in order to prevent tb.
of the electric circuit,
3. A switch including
means `for opening and closing a
switch contacts, overload means
contacts, conditions
said overload
for opening
means having
a second
resetting means being provided with meel
holding open the nrst set oi’ contacts dvi' .
resetting of the second set oi contacts, said over~
load means being constructed to prevent the Opern.
ing of the ñrst set or" contacts by the resetting
means while the second set of contacts are in
reset position.
4. A switch including means responsive to a
predetermined now of electric energy tlirougli an
electric circuit for opening the electric circuit, 3f
resetting means for said ñrst mentioned means
for moving the nrst mentioned means to closed
circuit position from open position, said resetting
means having protecting means for opening the
electric circuit during the resetting of said first 40
mentioned means, said resetting means being con
structed to prevent the actuation of the protect
circuit position iron: open position, and locking
reset position.
.ig the moving' of the re
means for closing the second set of contacts, .
resetting means for said ñrst mentioned means
for moving the ñrst mentioned means to closed
means ineffective
ing means when the first mentioned means is in
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