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Патент USA US2125201

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July 26, 1938.
Filed May 16, 1936 '-
2 Sheets-Sheet 1
84o 11 37
N° Rowg
R N P. Q vE
Filed May 16, 1936
2 Shee'tsuslme‘l 2
¥atented July 26, 1938
_ 2,125,201
Raymond N. Rowe, Plainville, Conn., assignor to
The Trumbull Electric Manufacturing Com
pany, Plainville, Conn., a corporation of Con
Application May 16, ‘1936, Serial No. 80,030
4 Claims. (or. 200-149)
My invention relates to circuit breakers. In
arc interruption, particularly for circuit break
switch and circuit breaker utilizing my inven
tion. The parts are in “on” position.
Fig. 2 is a vertical section along line 2-2 of
Fig. 1.
ers, a principle of'arc extinction known as com
pression interruption has been used. The pres
ent invention is an improvement in devices in
this ?eld of arc interruption.
Fig. 3 is a side elevation of some of the switch
One object of this invention is to simplify the
structure used in arc interrupters of the compres
sion type.
cuit breaker parts in “o?" position.
Fig. 5 is a similar view of these parts in
Another object is to strengthen the compres
slon chambers in these breakers.
“tripped” position.
Still another object is to improve the action of
Fig. 6 is an enlarged sectional view of ‘a com
pression chamber and contact carrier illustrating
the preferred form of my invention.
compression chamber seals in these arc inter
Fig. 4 is a sectional view of the switch and cir
Fig. 7 is an enlarged section of a modi?ed form
A further object is to make a chamber seal
that is comparatively inexpensive when com—
of seal for the contact carrier.
Fig. 8 shows another form of seal according to
pared to the seals now known to me.
my invention.
These objects, and others, are accomplished by
making a circuit breaker in which the contacts
As is
usual in breakers of the compression are inter
ruption type, the separated contacts draw an are
which heats the gases enclosed in the compres
sion chamber. The heating of these gases causes
25 them to expand, until the increased gas pressure
in the chamber produces an increase in the arc
drop su?icient to extinguish the arc.
Because this whole action depends upon a close
20 are separated within a closed chamber.
sealing of the chamber, it is important that-the
30 wall of the chamber through which any movable
contact is projected be provided with a strong
and eihcient packing or the like, to prevent es
cape of the gases under pressure. Leather, or
other ?exible, semi-resilient material, has been
35 used for this packing. According to the present
invention I make the seal for the movable con
tact member out of metal or other strong and
substantially in?exible and non-resilient mate
rial. However, the mere close ?tting of this seal
40 around the moving member is insu?icient e?ec
'tively to prevent escape of the heated gases. To
overcome this detect, the wall of the sealing
Fig. 9 shows still another form of seal for the
contact carrier.
In order to illustrate a completely operative 20
device I have shown a novel form of switch and
circuit breaker in which my improved chamber
seal is used. It should be understood that many
other suitable types of switch and breaker mech
anism could be used without departing from the 25
spirit of the present invention.
In the device shown, the switch has an insu
lating base l0 which may be connected to other
bases of identical switches by means of screws
or rivets II which pass through connecting straps 30
l2 and i3. As shown, two of these switches are
ganged together. It is obvious that they may
be used singly or in combinations greater than
two when desired.
Mounted on the base is a frame piece ll,
U-shaped in cross section, each arm of the U
carrying an extended leg I 5. Straddling the
frame is a switch yoke l8, pivoted as at H in a
recess of the base. The yokes of a plurality of
ganged switches are connected together by an
insulating connecting bar it, operated by a ban
dle l9.
member, or the wall of the movable contact car
rier, or both, is provided with a series of coarse
45 circumferential corrugations or serrations which,
as explained below, prevent escape of enough gas
. The switch throw piece 20 is pivoted on axis
2| between the arms of the frame and has a
cross bar 22 which connects the sides of the piece 45
In these drawings
Pig. 1 is a plan view of a two-pole ganged
spect to the pivot axis 2! of the throw piece and
the ends of the springs 25 that movement of the 55
together. At its lower end, the throw piece car
under pressure to affect the circuit-breaking op
ries a rod 23,_ which extends on either side out
side of the con?nes of the switch frame It. Be
In the accompanying drawings I have illus
tween each end of this rod 23 and ears 24 on
50 trated several forms that my improved seal may yoke ii are stretched springs 25. The rod 23
take, and have shown one form of switch and , passes through the contact-carrying plunger 26
circuit breaker which may be used in connection which has a contact 21 at one end. The posi
tion of the yoke pivot I l is so arranged with re
' yoke produces a snap action of the plunger and
contact in each direction.
A trip piece 28 is also pivoted on axis 2i in the
switch frame. This trip piece has a catch roller
C1 29 rotatablymounted between its sides. A re
setting bar 38 connects the sides of the piece to
Arms ti, on the trip piece 28, carry a cross
rod of catch 32 which ‘extends outward far
enough to engage one edge of the switch throw
piece 2b to' prevent clockwise rotation of the‘
throw piece beyond the catch. The free ends of
The walls of this sealing member ?t closely
around the surfaceof the, movable contact car
rier 2% but not tightly enough to‘ bind the parts
together. As shown' in Fig. 6, the walls of the
sealing member are provided with a serrated sur-’
face in the'form of a coarse screw thread sur
rounding the movable contact carrier. This is
the preferred form of sealing means by which
the compression within the chamber is main
tained-su?iciently high to aid in arc extinction.
The operation of the switch is as follows, as
suming the parts to be in the “off” position of
the arms 3i are engaged by a cross-head 33 on Fig. 4: the switch handle is and yokes it are
a bar 34!. This bar; is slidably mounted in a ' moved to the left, the springs 25 being put under
increasing tension. When' the springs have
stretched their maximum amount they start to
switch frame. A spring 3b surrounds bar ' Sél
contract, pulling the rod 23 to the left. This
and presses against head 33 and plate 35. These rod swings the switch throw piece 29 clockwise
parts areso positioned with respect to the pivot , and pushes the contact-carrying plunger rod 26
against stationary contact 53. The trip piece 28 20
2-) axis of trip piece 2t‘ that the spring 36 always
exerts a pressure tending to turn trip piece it and catch piece it do not move. _ The parts are
pressure plate 35 which in turn ispivotally held
at its ends by- seats in the ends of legs 85 of. the
in a counter-clockwise direction.
A catch piece 3? is pivotally mounted in frame
id as at 38 by ears or pivot lugs 59. One end of
this catch piece normally abuts against roller‘ 29
on trip piece 28, thus preventing spring 36 from
then in the “on” position of Figs. 1, 2 and 3.
Movement of the handle in the opposite di
rection causes the above mentioned parts to func
tion in a reverse manner, throwing the switch
into normal off position. Stops or lugs 5t on
pushing the trip piece to releasing position. See
Figs. 2 and a. To insure normal, engagement
the switch frame limit the extent of movement
with the roller 29, a small, light spring till is se
30 cured between the opposite end of the catch piece
When the switch is in “on” position, current
and a ?xed part of the switch base or frame.
adjusting or calibrating screw Ell is threadedly
engaged with the outer end of catch piece El and
is held in its adjusted positions‘ by lock-spring 62.
35 , This catch piece is actuated upon a short cir
cult or overload by any suitable electro-respon
sive device. As shown, the electro-responsive de
vice consists of a bimetallic strip d3, ?xedly
mounted at one end with respect to the switch
of _ the )switch yokes.
?ows from terminal to terminal through the fol? 30
lowing parts: terminal 6?, strap (it, screw con
nection 69, support dd, bimetallic strip as, cable
d5, plunger 26, contact 27!, contact 53, compres
sion chamber wall 52, connecting strip 55, and
terminal 56.
On a short circuit or overload the thermostatic
strip d3 will be heated and, flex upwardly. This
will trip the switch mechanism to separate the
The free end of the bimetallic strip is attached
contacts. >Action is as follows: when strip 43
?exes upwardly it lifts screw ?ll upward, tilting
catch piece 37 counter-clockwise around its piv~
to one end of a ?exible current-carrying cable
ots 39. f The other end of the catch piece will
40 base by conducting support dd.
(35, the other end of the cable being secured to then become disengaged from catch roller 29 and
one end of the contact plunger 26. This free end spring 36 isable to push trip piece 28 in its
of the thermostatic element will ?ex upwardly counter-clockwise direction. As soon as cross rod
when the strip is heated, thus engaging the end . or catch 32 engages the edge of the switch throw
of adjusting screw iii and tripping the catch piece 20, both throw piece and trip piece will
' piece 3? by overcoming theslight pressure of
counterbalancing spring QB. To prevent un
necessary current ?ow through the switch parts,
a strip of mica or other ?exible insulating mate
rial él? is secured to the top surface of the ther
mostatic strip 433 between the end of. screw tit
be pushed counter-clockwise together, and rod
23 with plunger 26 will be pulled away from con
tacting position; Springs 25 will also move to
pull yoke pieces it part way toward o? position.
rI'he yoke'and handle are prevented from going
to full “off” position by means of the trip resetting
and strip at.
piece 59 which is ?xed to the yoke piece 86. The
Current is supplied to the electro-responsive .under surface of this resetting piece will ‘engage element through support 65. Terminal d? makes resetting bar 36 of trip piece 28 and the ‘pressure
connection with a. strap £18, which in turn is elec
of spring 36 will prevent springs 25 fromv pulling
trically connected to support 4365 by means of a the yoke any farther. The parts are now in the
screw or the like 439.
“tripped” position of Fig. 5.
When a plurality of switches are ganged to
To reset the switch, after the ‘bimetallic strip 60
gether, adjacent catch pieces iii are connected ‘has cooled down and assumed normal position,
for simultaneous movement by means of an in
it is merely necessary for the operator to force
sulating bar it, held to the catch pieces as by the handle to full “01f” position. .
screws 5!.
When-the handle is so forced, resetting piece‘ ‘
The opposite current side-of the switch pref-v ' 59 bears against resetting bar 30 and pushes trip
erably contains the compression chamber. This
chamber is composed of‘ acup-shaped piece 52
which has a stationary contact piece 53 in its
piece 28 (against the action of spring 36) clock
wise into the position of Fig. 4. Counterbalance
spring 430 will pull one end of catch piece 31
bottom. The cup and‘contact are electrically downwardly and the other endnwill engage catch
. connected to terminal 58 by means of a strip ‘roller 29 to hold the trip’fpieciejin place. Reset
55. The edges of cup 52 are crimped around a. tingbar 3!! will also engage the upper surface of
heavy insulating tubed?, which ?ts the inside catch piece 37 to insure proper resetting at the
of the cup very closely.
Seated and sealed within the insulating .tube
75 56 is a‘ hard metallic hollow sealing member 57.
end of the switch handle movement; . The parts
are now all in the position of Fig. 4 because the
switch throw piece 20 and plunger 26 were al- 75
ready in “off" position and have been held there
by tension of the spring 25.
When the contacts 21 and 53 are separated
under load or short circuit, arcing will take place
within the compression chamber. Because the
chamber is sealed, the pressure, built up by, the
the screw thread grooves and the non-communi
eating circumferential grooves. This meaning
should be kept in mind in interpreting the scope
of the invention.
The switch mechanism per se is claimed in my
application Serial Number 100,414, ?led Septem—
expanding gases heated by the arc, will act to ber'12, 1936.
extinguish the arc. To seal the moving contact
I claim:
carrier at its place of entry into the chamber 1
1. In a circuit breaker, circuit making and
10 have provided the structure described above in . breaking means including a cup-shaped member
connection with Fig. 6. Other forms are illus
having a contact in the bottom thereof, a metal
trated in Figs. 7, 8 and 9.
bushing having an aperture in line with said con
It is theorized that the expanding gases, be
tact, insulating means interposed between the
cause of the serrations in the wall, are alter
bushing and the edge of the cup-shaped member
15 nately expanded and contracted. It is believed and extending inside the wall of the cup-shaped.
that this alternate expansion and contraction in member from the bushing part way toward the
rapid succession creates an obstruction to the bottom of the cup-shaped member, said cup
escape of the'gases and that this is why the shaped member, insulating means and bushing
proper compression is maintained in the cham
together constituting a closed chamber in which
20 her.
an arc may be formed, ,said chamber being of 20
In Figs. 6 and 7 the serrations are in the form
of coarse screw threads, in the ?rst case on the
inside of the aperture of the chamber wall, and
in the second case on the outer walls of the con
tact carrier. These two forms are preferred
mainly because of the extreme ease of their man
In Figs. 8 and 9 are illustratedother forms of
serrations, namely, a series of adjacent circum
30 ferential grooves.
In Fig. 8 these grooves are
within the aperture of the chamber wall, and
in Fig. 9 they are around the outer surface of
the contact carrier. The spiral arrangement of
the grooves in these forms does not seem to af
fect the e?iciency of the seal produced, probably
because the~ arc pressure is explosive in nature
and tends to act equally in all directions.
It should be understood that the contact car
rier of Fig. 6 may be used with the sealing tube
40 of either Fig. 6 or Fig. 8. The ‘contact carriers
of Figs. '7 and 9, however, may be used with the
sealing tubes of Fig. 6, Fig. 7, or Fig. 8.
Note that although I have shown a switch with
a contact carrier that reciprocates‘through one
walllof the compression chamber, other forms of‘
switches utilize contact carriers which have a
twisting or rotary movement through one wall
of a chamber.‘ My improved sealing means is
equally eifective in this other mounting of the
50 contact carrier and the appended claims should
be read with this in mind.
Because of the use of metal instead of other
material in my seal, the structure isvextremely
strong and durable.
The tendency of ordinary‘seals to cause stick
ing between the chamber wall and the moving
contact carrier is obviated by my improved struc
Another advantage is the fact that although
60 the present seal effectively holds the pressure
within the chamber during arc explosion, there is
such size that the heat of the arc is suiiicient to
raise gas pressure within said chamber to an
amount capable of assisting in choking the are,
a contact making plunger slidable in said aper
ture and having its inner end adaptedto make 25
and break contact with the contact in the bottom
of the cup-shaped member, the plunger and the
bushing having between themgrooves constitut
ing substantially the only passage for the relief
of gas pressure within said chamber, the ?t be
tween said sliding plunger and said bushing being
such as to effectively hold gas pressure within the
chamber during existence of the are but yet
capable of allowing a leakage of gas to substan
tially equalize the pressure inside and outside of
said chamber after interruption of said arc.
2. A circuit breaker having relatively fixed and
movable contacts between which an arc may form
on opening the circuit, a compression chamber in
which said arc is formed, said chamber being oi‘ 40
such size that the heat of the arc is su?icent to
raise the pressure of gas within the chamber to
an amount capable of assisting in choking the
are formed, a. movable contact carrier passing
through a wall of said compression chamber, and 45
gas sealing means around said movable contact
carrier where it passes through said chamber
wall, said sealing means ‘including a close ?t be
tween said-wall and carrier and a plurality of cir
cumferential serrations on either the movable
contact carrier or on the chamber wall around it 5.0
and through which it passes, the ?t between said
movable carrier and chamber wall being such as
to e?ectively hold the gas pressure within said
chamber during existence of said arc but yet 55
capable of allowing leakage of gas to substantially
equalize the pressure inside and outside of said
chamber after interruption of said arc.
3. In a circuit breaker having a ?xed and a
movable contact between which an arc may form 60
on separation of the contacts, a compression '
su?icient communication with the outer air to _ chamber around said contacts and in which said
enable the pressures inside and outside of the arc is formed, said chamber being of a size such
" 65
chamber to equalize by slow leakage after arc
interruption. This aids in cooling the chamber , that the heat of the arc may raise the pressure of
and shortens the periods during which the walls gas within the chamber to an amount capable of
of the chamber are subjected to internal pressure.
» A further advantage of my invention is the
assisting in choking the arc formed, a carrier for
the movable contact passing through a wall of
simplicity of the compression chamber structure.
70 The parts of this chamber are easily manufac~
said chamber, the improvement which includes
. tured and assembled, and produce a rugged, in
where it passes through said chamber wall, said
sealing means including a plurality of closely ad»
jacent circumferential serrations of generally V
expensive device.
In the following claims, I have used the words
“substantially ' circumferential
_ want of better generic terminology to cover both
a gas sealing means around the contact carrier
shape on either the movable carrier or wall of/the
chamber around the carrier, the carrier and the 75
contiguous portion of the chamber wall being oi through a wall of said compression chamber, and
metal and their ?t being such as to effectively
‘hold gas pressure within said chamber during
existence of said arc but capable of allowing
leakage of gas to substantially equalize the pres
gas, sealing means around said movable contact
carrier where it passes ‘through said chamber
wall, said sealing means including a close ?t be
tween said wall and carrier and a screw thread
sure inside and outside of said chamber after in
on either the contact carrier or the chamber wall
terruption of said arc.
contiguous thereto, the fit between the movable
carrier and the contiguous portion'of the cham
ber wall being su?lcient to hold the gas pressure
within the chamber during existence of said arc 10
but also capable of allowing leakage of gas from
the chamber to substantially equalize the pressure
4. A circuit breaker having relatively ?xed and
movable contacts between which an arc may form
10 on opening the circuit, a compression chamber in
which said arc is formed, said chamber being of
such size that the heat of the arc is su?icient to
raise‘ the pressure of gas within the chamber to
an amount capable of assisting in choking the arc
15 formed, a movable contact carrier passing
inside and outside of said chamber after inter
ruption of said arc.
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