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Sept. 10, 1946.
E. G. MILLER ETAL
2,407,378
SWITCH
Filed March 14, 1944
QM. \
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INÉNTORS
W
¿I
B
TQRNEY
Patented Sept. 10,» 194€
2,407,378
UNITED STATES PATENT OFFICE
2,407,378
SWITCH
Edward G. Miller and Ralph E. Engberg, New
York, N. Y., assignors, by mesne assignments, to
Allied Control Company, Inc., New York, N. Y.,
a corporation of New York
Application March 14, -1944, Serial No. 5426,37’7
2 Claims.
(Cl. 200-144)
1
2
This invention relates to switches and more
especially to switches for use in electrical ap
Fig. 2 is a view similar to Fig. l with the switch
in closed condition, and
Fig. 3 is a section on the line 3-3 of Fig. l.
A box-like casing iû of insulating material is
provided with a removable cover Ii attached to
the casing by fasteners i2. In the bottom of
the casing lil are two apertures I3 through each
of which extends a threaded binding post Id
having a head i5 co-nstituting a Contact. The
binding post ifi is hermetically sealed in a glass
bead i5 which in turn is hermetically sealed in
the bore of a metal bush il'. The assembly just
pliances for airplanes.
As is well known, the pressure within an air
plane varies to a considerable extent dependent
upon the elevation at which the plane is flown.
At certain pressures below normal surface level
atmospheric pressure, sparking between contacts
is materially increased. Thus, a switch which
operates without appreciable sparking between
its contacts at ground level will be characterized
by considerable sparking between the contacts at
elevations normally attained by airplanes.
An object of this invention is a switch hav
ing provision for satisfactorily suppressing arc
ing between the contacts when the switch is
carried by an airplane to high elevations.
described is a commercial product obtainable on
the open market.
A metal member iîl has an aperture through
which the binding post extends and a nut i9
threaded onto the end of the bolt iii holds the
binding post with the bush il engaging the inner
A further object of this invention is a switch
surface oi the casing bottom and the member i3
which may safety be used in an atmosphere con
taining explosive vapors or gases.
20 engaging the outer surface of the casing bot
tom. A Sylphon bellows Eil of either metallic or
A still further object of this invention is a
non-metallic flexible material has one end her
mounting for two relatively movable contacts oi'
metically sealed to the bush il and its other end
such nature that the atmosphere surrounding
hermetically sealed to a metal plate 2l support
the contacts is maintained of the same composi
tion and at substantially uniform pressure.
25 ing a Contact 22. The flexible wall chamber thus
formed may contain an arc suppressing atmos
In one type of switch embodying the inven
phere or may be evacuated to a degree sufñcient
tion, a pair of relatively movable contacts are
satisfactorily to suppress arcing.
arranged within an air-tight ilexible wall cham
A metal bridge member 23 contacts each of
ber and a suitable gas, for example, air, nitro
gen, etc., is provided within the container at pres 30 the plates 2| and is provided with a central
depression 24 between which and the bottom of
sure which will satisfactorily suppress arcing be
the casing is arranged a spring 25. A pin 2S
tween the contacts. Means are provided for ef
is slidably mounted in a frame 2l with one end
fecting relative movementI of the contacts toward
engaging the portion 24 of the bridge 23 and with
and away from each other. The chamber is so
mounted in the switch that at atmospheric pres- ` the other end enlarged to form a head 28 en
gageable with the frame 2l to limit downward
sure it is under slight compression tending to
movement of the pin. A leaf spring 29 is carried
by a bracket 3b attached to the wall of the
casing in by a screw 3| and engages the head
28. A cradle 32 is pivotally supported by a shaft
sure of the atmosphere surrounding the contacts .
33 journalled in the legs of a U-shaped member
remains substantially constant. Each chamber
42 supported by the side walls of the housing
may contain an arc inhibiting vapor, thereby
li] and having its bight portion extending be
minimizing arcing. Such a switch may also be
tween the lower surface of the frame 2ï and the
used in an atmosphere containing explosive gases
or vapors a5 any arcing which may develop be 4.5 upper surface of the depression 24 in the bridge
member 25, there being an aperture in said bight
tween the contacts will be wholly retained within
portion for the pin 25 to project through. The
the chamber.
relationship of the U member bight to the bellows
Other objects, novel features and advantages
members 2i) is such that when the bellows mem
of this invention will become apparent from the
maintain the maximum gap permissible between
the two contacts. Thus, irrespective of the ele
vation to which the switch is carried, the pres
following specification and accompanying draw
ing, wherein:
bers are assembled in the switch at surface level
atmospheric pressure the bellows 2i! are slightly
Fig. 1 is a vertical section through one em
compressed. A block of insulating material 34
likewise is pivotally supported by the shaft 33
bodiment of the invention, the switch being in
open condition and parts thereof being shown
in elevation;
and is provided with an operating handle 35 ex
65 tending through an aperture 36 in the cover H.
asevera
It
A plunger
4
extends through an aperture in
tacts thereiore remains constant irrespective
of the pressure surrounding the casing lil. Spark
ing between the contacts is thus satisfactoriiy
suppressed irrespective of the elevation at which
the switch may be operated, Also, the switch
the cradle 32 and is provided with a head 33
pivoted to the block ¿ill in a recess Z'lil provided
in the block by means of a pin All. A spring 4l
surrounds the plunger' Eil with one end abutting
the head 3B and the other end abutting the end
wall oi" the cradle. The cradle Si and the parts
may be made use of in an atmosphere containing
explosive mixture as any sparks that may be gen
associated therewith directly overlie the spring
2S.
erated upon opening- of the contacts are retained
within the chamber,
In Fig. 1, the parts are shown with the switch
in its open condition. The spring .'¿ál rests against
We claim:
1. A switch comprising a contact bridging mern~
the head 2d and the pin 2d together with the
bridge ZS and contacts
are held in elevated
position by the spring
and the expansive for-ee
of the bellows
Clockwise rotation of the block
3a by operation or” the handle
lifts the pivot pin
¿lil to reverse the position of the plunger ‘il rela»
tive to horizontal with the result that the cradle
32 is rocked countercloclrwise from the posi' ion
The
downwardly
shown
leftinend
Fig.to
or“l apply
the
to the
spring
pressure
position
is to
thereupon
shown
the bead
in iii . of
the pin 2:5 thereby forcing the bridge
and con»
tacts
downwardly against the action oit the
spring 25 into engagement with the contacts it“
to close a circuit between the two binding posts
lil.
The switch remains closed so long as
handlA Elli is lett
its lï‘ig. 2 position..
counterclocirwise movement of
he
-
_
,
Upon
the
switch returns to the position
In the event that the flexible che`I
tains an arc»suppressing atmosphe
pressure er higher or an inert g
pheric
example,
pressure
as nitrogen
or higher.
underAs
substant
an alte rnative, tho
flexible chamber
be
ed to auch degree
that
ionizing
thepoten
residual
Zal greater
gas inthan
the the
chamber
potential
hasto be
satisfactorily
applied between
suppressed
the contacts
under oroperating
that arcing
condim
tions for which the device is designed. The con
dition of the atmosphere surrounding the oon
ber arranged for rectilinear movement, a stop,
resilient means biasing said bridging member toe
ward said stop7 a pivotally supported hollow
.3)
rocker, a reoiprocable pin havin-g one end en
gaging
bridging member, a leaf spring ñxed
at one end and extending across the remaining
end of said pin in position to be engaged by said
rocker, an oscillating member within said rocker
20 coaxial therewith7 a stud pivoted at one end to
oscillatable member and extending through
f
aperture in said rocker, a shoulder on said stud
and a resilient member interposed between said
shoulder
rocker,
pin being eiîective upon
operation of :aid oscillatable member to move said
bridgiîg me
er away from said Stop.
A switch according to claim l characterized
by a pair oi' air»tight chambers each compris
two rigid metal end members interconnected
by a metal bellows member, means supporting said
c*
nibers with one end member of each chamber
ai and the other end member capable ci :nove
rnent toward and away from
fixed end mein»n
ber and arranged for engagement by said bridg
ing member, a contact supported by each member
ci" a chamber within said chamber with one
Contact of each chamber insulated from its sup«
porting member, and a conductor leading through
each stationary end member to the Contact sup
ported thereby.
ED'WARD G. MILLER.
RALPH E. ENGBERG.
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