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Патент USA US2407711

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Sept 17, 1946-
,
F. G. LOGAN
. ELECTRIC
2,407,710
SWITCH
Original Filed Nov. 6, 1941
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J
8“
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6
I
8574
3 Sheets-Sheet l
Sept. 17, 1946.
‘
F. G. LOGAN
2,407,710
ELECTRIC SWITCH
Original Filed Nov. 6, 1941
‘
a
-
a
if. 5719/ ?fjzgwgagw 30 /£
I
/
3 Sheets-Sheet 2
Sept. 17, 1946.
I
F, G, LOGAN-
2,407,710
ELECTRIC SWITCH
Original Filed Nov. 6, 1941
3 Sheets-Sheet 3
2,407,710
Patented Sept. 17, 1946
UNITED STATES PATENT OFFICE
2,407,710
ELECTRIC SWITCH
Frank G. Logan, Mount Vernon, N. Y., assignor to
Ward Leonard Electric Company, a corporation
of New York
Original application November 6, 1941, Serial No.
417,990, now Patent No. 2,378,022, dated June 12,
1945. Divided and this application March 27,
1943, Serial No. 480,767
4 Claims.
(Cl. 200—144)
2
1
This invention relates to electric switches
adapted for general use and for control purposes
and is of the magnetically operated contacting
type although certain features of this improve
ment are applicable to other types of switches.
Certain of the improvements disclosed herein and _
not claimed are the inventions of George M. Sta
pleton and are described and claimed in his pend
ing United States application Serial No. 420,327,
?led November 25, 1941, now Patent No. 2,378,162,
issued June 12, 1945.
This application is a division of my pending
original application Serial No. 417,990, filed No
vember 6, 1941, now Patent No. 2,378,022, issued
15
June 12, 1945.
The general object of the improvements de
scribed and claimed herein are to produce an im
proved switch which is of compact form and of
comparatively large current and rupturing ca
pacity, and which will be durable and dependable
under long continued use. A particular object is
to provide an improved form of arc chambers and
relationship to the contacts for effectively
quenching the arc and occupying small space.
This is accomplished in general by providing arc
chambers which individually encircle the con
tacts in comparatively close proximity thereto
ple provision of arc quenching and cooling sur
faces within the arc chambers; and the relation
ship of the parts is such that the arc is electro
magnetically forced against the walls of the
chambers which are opposite the cut-away por
tions which insures the effective cooling and
quenching of the arcs by the arc barrier surfaces
on the opposite side of the chambers from the
cut-away portions. The are chambers or shields
are preferably made of metal as such material
can effectively withstand the heating effects of
the arcs without objectionable deterioration and
the high thermal conductivity of metal assists in
the cooling of the arc and the heated gases.
Either magnetic material, such as iron or sheet
steel, may be used for the arc chambers but non
magnetic material, such as brass likewise may be
used. Also, the chambers may be made of other
suitable material than metal which is adapted to
effectively withstand the e?ects of the arcs and
hot gases without objectionable deterioration of
the exposed surfaces.
Other objects and advantages of this invention
will be understood from the following description
‘ and accompanying drawings which illustrate one
embodiment of the invention.
Fig. 1 is a vertical central section in a plane at
right-angles to the back of the switch; Fig. 2 is a
and by mounting them so as to be movable with
top plan view with the connecting terminals
the movable contacts of the switch. The im
proved construction permits the arc chambers to 30 shown in section; Fig. 3 is a horizontal section on
the line 3—3 of Fig. 1; Fig. 4 is a horizontal sec
be made of light weight and of a sturdy form of
tion on the line 4-—4 of Fig. 1; Fig. 5 is an en
structure that will effectively cool and quench
larged side view, partly in section, of one of the
the arc and permit the effective carrying away of
?xed contacts; Fig. 6 is an enlarged perspective
the hot gases upwardly in their natural tendency
to rise. The permissible proximity of the arc 35 view of one of the arc chambers or shields; Fig. 7
is a vertical section on the line 1-1 of Fig. l; and
chambers to the contacts has the advantage of
‘Fig. 8 is a horizontal section on the line 8—8 of
rapidly cooling the arc and heated gases and by
Fig. 7.
reason of the fact that the chambers are movable
The apparatus is supported by a frame or base
'with the movable contacts, there rises the advan
tage of exposing fresh arc barrier surfaces to the 40 of sheet metal having a general U-shaped form..
are continuously during the opening movement
The base of the U extends verticallyv and the two
of the contacts. Also, during the opening move
ment provision is made not only for the escape
of hot gases upwardly but for providing free ac
side portions extend forwardly from the base por
tion. The rear portion of the frame is corrugat
ed for strength, the projecting ribs Ia which
cess of air to the bottom of the chambers so as 45 extend vertically along the back, being forced
to permit a free and enforced movement of the
forwardly from the metal sheet before it is cut
hot gases upwardly and permit them to escape
and bent to the desired form. At about the
through the top of the arc chambers to the out
middle of the back portion, two of the ribs la
side atmosphere. The free upward passage of the
are further pressed forwardly forming project
hot gases is facilitated further by cutting away 50 ing ribs lb, as shown in Figs. 1 and 4, for a pur
pose later explained. The back portion is pro
the lower parts of the arc chambers to permit free
vided with openings Ic at the top and bottom, as
inward passage of air upwardly through the
shown in Figs. 1 and 7, for the purpose of secur
chambers and these cut-away portions of the
‘ing the frame to a supporting panel. The for
chambers also permit entrance of the supports
for the movable contacts while maintaining am 55 wardly extending side portions Id are provided
3
2,407,710
with a number of openings to as shown in Figs.
7 and 8 for the purpose of ventilation and ac~
cessibility during assembly, and in repair or ad
justment of the parts. A number of projecting
portions extend from the side portions and are
bent inwardly at right-angles at the front of
the frame for forming supports for various parts.
A pair of these projections if, shoWn in Figs. 1
4
5 is free to be raised from the frame and thus per
mit the front edge of the block to be withdrawn
from under the clamping extensions 2a. Thus
the insulating block 5 may be readily removed
and replaced, together with the parts carried by
it, for inspection, cleaning or adjustment of the
parts.
The block or head 5 is provided on its upper
and 2, forms a support for a front plate 2 which
surface with ribs So, as well shown in Fig. 7,
may be utilized for supporting auxiliary conti. o1 1O which extend from front to back and also an up
apparatus or parts and also serves another func
wardly extending rear cross-rib lib, as shown in
tion to be described later. The plate
is also
Fig. 1. These ribs are for the purpose of
secured to a pair of inwardly turned projections
strengthening the block and for also separating
considerable
lg of the frame
portion
whichofextend
the frame.
vertically
A pair
along of
the upper portions of the ?xed contacts which
portions lie in the valleys between the ribs. The
similar projections lh are positioned below the
fixed contacts are in the form of downwardly
projections lg, as shown in Fig. l, and serves,
extending metal rods 7, the lower ends of which
together with the projections lg, to support an
form the contacting faces of the ?xed contacts
other front plate 3 which may be utilized for sup
which faces are preferably formed. of silver, or
porting auxiliary control apparatus or parts. A
alloys of silver, or other suitable material, for
pair of similar projections it from the frame are
obtaining good contact surfaces. The upper
positioned below the projections lh and serve
ends of the contact rods or cylinders l are of
to support another plate
the purpose of which
reduced diameter and project upwardly through
will be later explained. The extensions lg carry
openings in the head 5, being secured to the head
at their upper middle portions a pair of projec'~
by washers and nuts la. on the upper threaded
tions i7", as shown in Figs.
and 3, which are
ends of the contact rods. The upper ends of the
curved inwardly and outwardly and serve a pur~
contact rods are slotted so that they may be held
pose later explained. They are opposite the proby a screwdriver from turning while the clamp
jections lb of the rear portion of the frame. The
main frame and its various extensions and pro 30 ing nuts la are turned tightly for locking the
parts in ?xed position. The lower portion of each
jections not only serve for supporting various
fixed contact rod is encircled somewhat above its
parts but also accomplish other objects, as later
lower end by a ring 8 of insulating material, as
described.
shown in Fig. l and more particularly in Fig. 5.
In describing
construction of the switch
This insulating ring may be secured to the rod
and the relationship and operation of its parts,
in any suitable manner but, as shown in Fig. 5,
the upper portion will ?rst be described and the
is held in place by spinning or upsetting a por
description continued by reference to the other
tion of the metal rod 1, as shown in Fig, 5,
- parts
in progressive steps downwardly. The
against the upper and lower inner edges of the
?xed contacts and inter-connections thereto are
insulating ring. This ring acts as a Spacer on
supported by a block 5 of insulating material
each
?xed contact for preventing engagement
molded to the desired form. It extends horizon~
with adjoining parts and likewise as a barrier,
tally across the upper portion of the switch and
although permitting free escape of the gases up
is supported at its sides by resting upon the side
wardly around its outer rim. In the particular
portions id of the frame, as shown in Fig. 7 and
switch shown, there are twelve ?xed contacts 1
upon the front projection if as shown in Figs, 1
in three rows of four each. The front and rear
and 2. The front tie plate 1! is provided at its
contacts of each row are adapted to be connected
upper part with a pair of inwardly extending
to the controlled circuit, or circuits, by terminal
projections 2a which extend over the front edge
connections in the form of ?at strips 81) which
of the insulating block 5 and thereby serves .to
are bent to extend under the clamping nuts la
hold the front portion of the block in ?xed posi
tion. The rear portion of the block 5 is held in
place by a cross-pin t which extends over the
rear part of the block, as shown in Fig. 1. This
and locking washers on the contact posts and are
provided at their outer ends with screws 8a and
locking washers for receiving the conducting
leads. The inner two contact posts of each row
of the frame. The outer ends of the pins are 55 are connected by a metal link 9 which lies on the
top of the contact head and extends under the
formed with circumferential grooves which are
clamping nuts 1a and washers of the two contact
engaged by spring clips 6a, as shown in Fig. 2,
posts. The two front contact posts of each row
for preventing endwise movement of the pin.
are adapted to be bridged by a movable contactor,
When it is desired to remove the block 5, it is
as indicated in Fig. l, and the two rear contact
‘merely necessary to remove one of the Clips 611
posts of each row are adapted to be bridged by a
and then move the pin 6 endwise a short distance
contactor. Thus the circuit may be traced from
so as to clear the inside of a side portion of the
the
outer terminal 8a of one row through the
frame and then by raising the free end of the pin
front contact post and bridging contactor to the
and after removing ‘the other clip 6a, the pin can
be withdrawn from the other side of the frame. 65 second contact post and then through the link 9
to the next contact post and thence through the
The slots lk permit this tilting and their ?nal
rear bridging contactor to the rear contact post
removal from either side of the frame as may be
and rear terminal 8a. When the circuit of each
desired. Of course, the pin may be removed by
row is opened there are thus secured four breaks
pulling it out longitudinally after removing one
in the circuit in series with each other which
of the pins 6a but where a number of these
tends to reduce the arcing at each contact. The
switches are stacked side by side closely in a row,
provision of the terminals affords means for con
the above described tilting method of removal
necting the switch in any way desired to the out
of the pin can be accomplished even though an
side circuit and by locating the links 9 at the top
other switch is mounted closely on each side.
After removal of the pin the rear end of the block 75 of the insulating head, they are conveniently ac
cessible and removable if desired for replacement
pin extends through slots tic in the side portions
2,407,710
by the connection of overload controlling devices
contact [50; which is securely fastened to the
piece 15‘ as by riveting or otherwise. These con
between the inner terminals of the different rows,
tacts are preferably formed with a face of silver
or by the connection of ammeters or other de
or silver alloy for insuring good contact with the
vices for particular purposes.
?xed contacts when engaging them. Each of
The movable contact assembly is formed of two
these bridging movable contact assemblies ex
separable blocks of molded insulating material
tends through the cut-away portions Ma of a pair
which are securely clamped together for holding
of shields so that the contact faces are centrally
the various associated parts in place. The lower
positioned within the shields and opposite a pair
insulating block it extends horizontally between
?xed contacts, as shown in Fig. 1. Each bridg
the side portions of the frame. The upper block 10 of
ing contact is kept in proper alignment by a
I l similarly extends horizontally between the side
contact guide [6 in the form of a metal strip of
portions of the frame and is removably secured
rectangular form, as shown in Figs. 1 and 3. The
to the lower block by screws l2, well shown in
lower end. of each of these guiding strips is
Figs. 3 and '7, which pass vertically down through
knurled or roughened and is forced into an open
the upper block and lower block and have a 15 ing in the insulating block In so as to be ?rmly
threaded engagement at their lower ends with a
retained in position by the block Ill. The strips
channel shaped sheet metal strip [3 to be later
are'secured in position in the block in before the
described. The lower insulating block in is pro
block II is fastened thereto; and the openings
vided with a number of vertical openings lila
formed in the insulating block I l for reception of
each of which is below and opposite the previous
the upper ends of these strips are of suf?cient size
ly described ?xed contacts. These openings are
to freely receive the upper ends of the strips in
for the purpose of providing a free flow of air up
assembling the parts. Each bridging piece ii of
wardly to and beyond the contacts to aid in ex
the movable contacts is provided with a central
tinguishing the arcs and in carrying away the
slot of the same form as the cross section of the
hot gases. The upper block H of the movable
strip and is adapted to freely move along the
assembly is provided with twelve cylindrical
guiding strip. A spring I‘! encircles each guid
openings I la which are opposite the contact posts
ing strip l6 and one end of the spring is posi
‘I and these openings extend vertically down
tioned below each of the bridging pieces 15 while
ward and communicate with the openings Ida in
the other end seats in an opening formed in the
the lower block It], as well shown in Figs. 1 and '7. .
A cylindrical arc shield or barrier i4 is positioned
within each of the openings i la and each of these
shields extend upwardly above the block II a
short distance and the upper end of each shield
insulating block l0.
-
The movable contact assembly, as previously
described is composed of two separable blocks of
molded insulation fastened together and they
surrounds the insulating ring 8 ‘but is spaced
support and carry the arc barriers or shields as
therefrom to permit the free escape of gases up
wardly between the shield and the insulating
ring. The lower portion of each shield is cut
fastening ‘screws 12 serves as a common means,
away at Ma on one side, as particularly shown in
Fig. 6 and'a space Mb is left between the edges
of the upper portion of the shield. The lower
portion of the shield is ?ared outwardly at 14c
and, as well shown in Fig. l, the adjoining por
tions of the insulating blocks Ill and I I are shaped
to receive these ?ared portions of the shields so
that when the two insulating blocks are clamped
together by the screws l2, the shields Iii will be
held in ?xed position. Provision is also made for
insuring that the shields are maintained in their
proper positions with reference to the movable
well as the spring pressed bridging contacts. The
not only for holding the insulating blocks it and
H together, but by engaging the metal piece iii
of U form, serve to hold all parts of the movable
contact head together.
The parts are shown in the open position of the
sWitch and when the part i3 is moved upwardly
upon the energization of the magnet, the movable
contact assembly including the arc chambers or
shields iii, is moved upwardly and thereby cause
the bridging movable contacts to engage their re
spective pairs of ?xed contacts 1. After initial
engagement and upon further upward movement
' of the parts, the movable bridging contacts are
forced downwardly by their engagement with the
contacts. This is accomplished by forming ver
?xed contacts along the guiding strips to against
tical projections Ilb on the insulating block II
the pressure of the springs 11. As the bridging
which project within the openings Ha, as shown
contacts have a certain freedom of movement on
in Fig. 3. The width of each projection llb cor
- the guiding strips, they are self -adjusting so that
responds with the opening Mb of each shield and
the pressure of the movable contacts against the
when the shield is passed into its opening in the
?xed contacts is equalized, thereby insuring
insulating block, the vertical edges of the upper
proper engagement and sufficient contact pres
portion of the shield will engage the projection
sure of each movable contact with its ?xed con
l lb and thereby insure that each shield is main
tact. Also, by reason of the movable contact
tained in its proper position. The barriers or
assembly being pivotally connected, as herein
shields [4 may be formed of sheet metal and it
after explained with the actuated portion of the
should be noted that each of these shields is in
magnet, the movable contact head is capable of
dividually insulated from other portions of the
movement as a whole 50 as to be self-adjusting in
apparatus. Metal shields are desirable owing to
their ability to resist objectionable disintegration 65 relation to the ?xed contacts in order to further
insure equalization of contact pressure in all
from effects of arcs; and either magnetic or non
magnetic metal may be used, such as iron or brass
parts.
When the magnet is deenergized for opening
but the shields may be made of material other
the switch, the pressure of the contacts and the
than metal which will retain its form and be
springs I1 together with the weight of the parts,
capable of withstanding the eifects of the arcs.
70
force the movable contact head downwardly with
Each of the movable contacts bridges a pair of
a quick opening movement. In this opening ac
?xed contacts, as shown in Fig. 1, and is in the
tion the arc barriers are, of course, moved down
form of a sheet metal channel piece l5, as well
wardly with the movable contact head and this
shown in Fig. '7 and is preferably made of cop
action results inconstantly bringing fresh sure
75
per; and this channel piece carries at each end a
2,407,710
faces ofgthe. shields oppositethe arcs and thereby
aid .in-coolingand. extinguishing'them. .Further
more, by bringing new surfaces opposite the arcs,
the arc. chambers are lesssubject .todeterloration
from effects .ofthe‘arcs, as compared with ?xed
arc barrierswherethe arcing effects are concen
tratedon the same portions of thebarriers. .Also,
the .free spaces betweenthe arc chambers and
8
opened vat'auxiliary .control contacts by ‘severe
shocks on the apparatus.
Referring to Fig. l, the three~legged~form ‘of
the laminae E8‘ of the non-actuated portion ‘of
C2 the magnetis shown as having the legs extend
ing vertically downward and the three-legged
laminae l9 of 'the actuated portion of themag
net is shownwith :its legs extending upwardly
the ?xedcontacts and aroun'dthe insulating rings
8_ provide open passages for-the. free ?ow of the 10 and, asalready explained, the engagingfacesof
the legs are ground, after assembly,;in the same
hot. gases upwardlyin their natural tendency of
movement and out through the top of the cham
bers, this free. passage of thechot gases upwardly
and outwardly being assisted by the free inflowof
air through the openings 10a below each of the
plane so as to insure ‘uniform, good surface con~
tact.
The end plates 18a of the non-actuated
portion ofthe magnet core are shown inFig. .4
as‘provided at each end with angular extensions
lGb which . project .rearyvardly and forwardly.
These extensions respectively engage sheet . metal
contacts. The are chambers also serve to-cool
the hotgases as they pass freely upwardly and
brackets v2i! which. are bent toladesiredishapaas
out from the chambers. ‘The cut-awayportions
shown, andprovidedwith side portions-Hailey
of the chambers for thepurpose of permitting
whichithey
are securely fastened to the side por
the introduction of the movable contacts and
0f the bridging elements carrying them, do not 20 tions of the main frame by the .screws'ZlJb. The
projections 132) from .the end plates loosely en
lessen the effectiveness of the structure in ex
gage vertical Slots .230 in the cross brackets :20
tinguishing the arcs because, with reference .to
so ..as.to permit considerable “freedom ‘of move
each, pair of. contacts, the current passes through
ment. of the.noneactuatedrportion.of the magnet
a loop formed by one ?xed contact, the bridging
contacts and the other ?xed contact which re 25 in all directions for the purposeof self-adjust
ment, as later explained, but .is, of course,:re
sults in forcing the arcs outwardly from the loop
strained by the slots from assuming extreme-or
always against the portions of the chambers
abnormal positions. :In assembling'the core of
which are not cut away. The cut-away portions
tl'ie.=non-actuated.portion of ' the-magnetythe end
of. the chambers serve also to facilitate the inward
plates l?cz having the .projections 18b :are .per
passage of air to the chambers ‘to aid in the up
manently fastened to the laminae, .as by rivet
ward and .outward passage of the hot .gases
ing, andthe pole faces afterwards ground. This
through the chambers.
eliminates possible .clistortionofthe parts which
The function of the inwardly pressed projec
might occur if the end plates or their supporting
tions 11) from the rear of the‘ main frame and of
extensions were attachedai‘tcr grinding. The
the projections I?‘ at the front :portion of ‘the
magnet coil 2| is carried by aispool ‘Zia of-insu
frame on opposite ends of the movable contact
lating material and is held in.place,1as shown in
head is for restraining the‘rnovement of the head
Fig. .7 by a U-shaped strip 25 of ‘metaL'the .base
under shocks and jars. The movable head is nor
of .the U passing over the top of the laminae
mally guided in its movement by parts hereinafter
described ‘but the projecting portions referred to 40 l8 and the legs extending downwardly inside-the
vereconditions for preventing the ‘movable head
magnet'coil. The'supporting strip 23 isprovided
with outwardly extending projections 23a at the
being jolted to an abnormal ‘position, as one of
lower ends of the legs which pass under and sup
serve as restraining means under unusual or se
portthe magneticoil.
Tl‘hev actuated portion ‘of the .magnet. compris
tation to withstand severe shocks and jars as, for 45
ing the laminae. l 9 isprovided with end platesv l9a
example, when used on naval vessels.
which ‘extend along. epposite‘sides of the laminae
The magnet core actuating the switch to closed
andiare bent. at right-angles, as shownin. Fig. 8,
position is composed of two similar laminated
to' pass inwardly overtheends of the‘laminaeiand
parts and on account of the fact that the part
corresponding to- the usual ?xed part is movable 50 again bent: outwardly:atJright-angles to formex
tensions I'Sb. ‘These end extensions are spaced
for-the purpose of ‘securing self-alignment and
from ‘each other for :receiving the driving rods
self-adjustment, it will be referred to herein as
Ztwhich latter are'connected vfor actuation of
the non-actuated part of the magnet and ‘the
the. movable. contact‘ head. At thezfront portions
other-‘part as'the-actuated part of the-magnet.
Each part-is built up of laminations of general 55 of the end plates l?a is‘secured .aipair of angular
pieces 25‘which are bent at right-angles sales
E-form'and'the laminae‘ of each part are of the
to extend toward itheside portions of the main
same size-and shape which simpli?es the stock
frame as shown'in Fig. 8. Innassembling the
ing problem and the cost of assembly. The faces
core structure ‘of theactuated-part of ‘the mag
ofthe ends of the three legs ofthe E are ground,
afterassembly- of the core parts, to lie in thesame 60 net, theend plates L911 and the angular pieces
25 are permanently ‘fastened together and tothe
plane; and-when thelparts arein their attracted
laminaeasbyriveting theparts, after which the
position, there is no air gap between the engag
pole faces .:of this portion of the : magnet are
ing faces-of the core portions. This not only
ground in a single operationin'thesame plane.
simpli?es ‘the cost ofnianufacture by permitting
the grinding of the engaging faces by one opera 65 This avoids possiblefdistortion. of ‘this portion
tion in the same plane but the omission of any
of the magnet which :otherwise might .occur if
air gap results in the advantages of lower'volt
the end platesor pieces ‘25 werezattachedi to the
ampere input to the magnet ‘coil, uniformity of
laminae after the grinding.‘ operation.
coil inductance and a slight time delay before ac
There are :two driverroids ‘24, .one in :the back
tuation of the ‘switch to open position, due to
and
oneinithefront portion'of the'apparatus,
higher residual magnetization and higher in
for connecting .the. actuated :portion of the. mag
duced-secondary currents in the iron core, the
net with the ‘movable contacthead. 'These ‘rods
last named advantage being particularlydesira
areof ‘square "cross section, .as shown in Fig. .4,
ble in overcoming the opening. of the switchwhen
the; purposes of this'improved switch is for adap
the circuit of .the magnet coil is momentarily
andare pivotally connected by pins'l24a. between
the extensions r Nb :of theendsplatesras :showniin
2,407,710
10
tive position of the parts is secured for insuring '
Fig. 8. The drive rods extend upwardly from
these pivotal connections and are loosely guided
in their movement by the two brackets Zil, as
shown in Fig. 4, these brackets being bent at
their middle portions to form vertical guiding
a uniform and balanced engagement of the parts
in proper alignment and insures a minimum noise
level in later use after the magnet is energized.
The usual lag loop or coil is provided within
the faces of one or more poles of the magnet and
channels for the rods. The upper ends of the
rods are riveted, or otherwise ?rmly secured to
the ends of metal strip or yoke 26 of channel
in the present structure this is preferably in the
form of a rectangular copper loop 28, as shown
in plan view in Fig. 8 and held in place by up
form, the bent side portions extending upwardly,
setting portions of the edges of the'lalninae over
as shown in Fig. 7. These side portions fit freely 10 the loop. As shown in Fig. 1, one of these lag
within the downwardly extending side portions
loops is provided on the outer pole face of the
of the strip or yoke [3 which has been previ
ously described as being fixed to the movable
contact head by the screws E2. The two yoke
nonactuated portion of the magnet, while the
pieces are pivotally connected together at their
magnet. This relative arrangement insures that
other of the lag loops is provided on the face
of the inner pole of the actuated portion of the
middle portions by a pin 21, as shown in Figs. 1
and '7.
Thus the actuated portion of the magnet is
not only pivotally connected to the drive rods
but there is also a pivotal connection between
the yoke of the drive rods and the yoke of the
movable contact head. This gives a ?exibility of
at least one of the two engaging faces of each
pole of the magnet will be a solid, smooth face
and thereby avoid distortion or unevenness of
the pole faces under continued/use. These lag
loops are applied to and secured in place on the
two portions of the magnet before the ?nal grind
ing operation of the pole faces.
Special additional provision is made for pre—
venting undesired opening or closing of the switch
movement between the parts and provides for the
self-adjustment and alignment of the parts for
insuring the proper seating of the pole faces ~
of the magnet and aids in the proper seating
and balancing of pressure of the contacts. The
axes of these pivotal connections are at right
angles to the side plates of the main frame and
to the bridging movable contacts for permit- j
when subjected to severe vertical shocks or to
vertical components of shocks. This is accom
plished by the pro-vision of inertia controlled
latches, the operation of which is dependent upon
change of motion of the entire structure. One
of the latches is for preventing the switch from
closing under severe shocks and the other is for
ting self-adjustment of the parts in planes per
pendicular to the back portion of the main frame;
and the slight looseness of the connections per
mits sufficient freedom of movement for adjust
ment in the direction of planes parallel to the 3
back portion of the main frame.
Also, instead of providing a heavy main sup
porting frame in the attempt to secure rigidity of
the non-actuated part of the magnet in a fixed
position, the non-actuated part of the magnet
is mounted, as already described, so as to be
movable with reference to the supporting frame
and movable with reference to other parts of
the switch for securing proper alignment and
40
preventing the switch from opening under severe
shocks.
One of these inertia latches is shown
in the lower right-hand portion of Fig. 1. ‘It
comprises a weighted body portion 29 which ex
tends across the lower front portion of the main
frame, as shown in Fig. 8, and is provided With
a latch 29a at each end which eXtends upwardly
and is provided with an inwardly projecting
hooked end. These two ends of the latches are
normally positioned, as shown in Fig. 1, some
what above and in front of the angular pieces
25 secured to the actuated portion of the mag
net core. The two latches are pivoted on a pin
engagement of the parts by self-adjustment. 45 3%! which is supported at its ends‘ in the side por
This avoids the time and expense otherwise re
tions of the main frame. The weighted portion
quired to machine the parts to close clearances
25! of the latch being positioned outwardly from
and likewise avoids the time and care required
the pin 3%, tends to maintain the latches in the
in making refined adjustments after the assem
position shown in Fig. 1 out of engagement with
50
bly of the parts. Furthermore in the prior rigid
the angular pieces 25. An adjustable screw 3!
and attempted perfectly aligned structures, the
mountedon the tie-plate 4 limits the outward
alignment is not permanent, especially when sub- ,
movement of the latches. The radius from the
jected to severe shocks, owing to the distortion
axis of the pin 33 to the center of gravity‘of
of the parts which inevitably follows pronounced
the mass 29 is shorter than the distancefrom
shocks and jars. In the present form of con
the axis of the pin 30 to the hooked ends of the
struction the free ?oating and self-adjustment
latches. It follows that any movement of the
of the parts with reference to each other insures
mass 29 about its pivot is ampli?ed in the move
permanent and proper relationship of the parts
ment of the hooked end of the latch in proportion
which is not affected by distortion of the main
to their relative distances from the pivot pin.
support or other parts of the apparatus. More GO Under normal conditions the latches are out of
over, with this improved structure the proper
engagement with the angular pieces 25 and thus
seating and self-alignment of the parts give con
energizing of the magnet coil will permit the
tinued quiet operation when energized and in
switch to be closed in the manner already de
fact becomes more quiet with continued use ow
scribed. But if the switch is in the open position
Li
ing to continued improvement in the surface
and the apparatus is subjected to a severe verti
engagement of the parts the longer the switch is
cal shock, or to the vertical component of such
used.
a -shock,_ the actuated portions of the switch
In assembling this improved structure, the parts
might move with relation to the fixed contacts
are connected together as described except that
and result in an undesired closing of the switch.
the screws Ziib which hold the cross-brackets 2!! TO However, before this can occur, the mass 29 will
to the main frame are left to loosely engage the
move upwardly and by the ampli?cation of move
parts until after the magnet is energized when
ment referred to, the hooked ends of the latches
the screws 29b are tightened up gradually in
will be rapidly moved inwardly and engage the
succession a little at a time until they are all
angular pieces 25 before the switch can close and
uniformly tight. In this manner the best rela
2,407,710
11
thereby restrain and prevent the closing of the
switch. After the passing» of the shock the iner
tia latch will fall to its normalposition so that
the switch will be free to close upon energization
of its'magnet.
A similar inertia latch or stop prevents the un
desired opening of the switch under severe verti
cal shocks by a reverse manner of operation.
A
mass 32 is positioned at the lower central portion
of the switch, as shown in Fig. l, and extends
crosswise between the side portions of the main
frame. The mass is provided near its ends with
supporting plates 32a which are pivotally mount~
ed upon a; pin 33. which extends. between and is
supportedby theside DOl'tlOI'lSzOf the mainframe.
Between; the extensions 32a. is..a cross-bar 32b,
theupper portion of. whichisnotched at 3.20. A
spring,“ is connected. at oneendtotheweight
32 and at its other: end'to the. pin 30 for nor
mally holding this shock preventing-means. in
the position shown in Fig. 1. The mass 32' is
provided with extensions 3211 as. shown in Fig. 7
which normally engage the lower edges of the
side portions of the main frame for limiting the
upward movement of. the restraining means to
the; position shown in Fig. 1. When the switch
isclosed, the. lower inside corner of the actuated
portion of the core is positioned opposite and
above‘ thenotch 320 of the inertia latch. When
the apparatus is subjected to
a severe vertical i
shock, .or to a‘vertical component thereof, when
the vswitch is‘closed, the opening of the switch is
prevented because‘ any tendency to open the
switch will cause‘ the' mass. 32 to move downward
ly and due to the ampli?ed relative movement of
the notch 320 by reasons of its distance from its
axis from the pin 33 being greater than the dis
tance from its aXis'to the‘ center of gravity of the
mass 32, the notched portion 320 will move un
der thelower inside corner of the actuated core
12
2\.'An electric switch comprising a?xed insu
lating support, a contact carried thereby and .ex
tending downwardly therefrom, a vertically mov~
able insulating support below said ?xed contact, a
contact carried by said movable insulating'sup
port and adapted to engage said ?rst named con
tact upon the upward movement of said movabl
insulating support, a vertically extending arc
shield of metal surrounding and spaced from said
contacts throughout the length of the shield and
?xed at its lower end to and insulated by said
movable insulating support and having openings
at both of its ends, said movable support having
an opening opposite the lower end of said are
shield for the free passage of gases therethrough
and. upward through the space between. the arc
shield and the contacts for extinguishing theharc
upon the opening of the switch, and thedown
ward movement of said insulating support and of
said arc shield exposing fresh surfaces of lil'lli‘l‘l’l
terior of said are shield to the effects oi the arc
during-the separation of the contacts in the open
ing movement.
3. An electric switch comprising a fixed insu
lating support, a pair oil-contacts‘ carried thereby
and extending downwardly therefrom, a movable
insulating support, a pair of contacts connected
by a bridge and carried ‘by the movable insulating
support for engaging the ?rst named pair of con
tacts respectively upon the upward movement of
the movable insulating support, a pair of arc
shields carried by said movable insulating sup
port, each of said shields having a top opening,
said shields surrounding each pair of the engag~
ing contacts respectively and spaced therefrom
throughout the length of each shield for provid
ing an intervening air space between the shields
and the contacts for permitting the free passage
of gases from the arc therethrough, each of said
portion of the switchbefore the switch has had 40 shields having a side opening opposite the side
time to open. This action will prevent the open
opening of the other shield for receiving the
ing of the switch until the full eifects of the shock
bridge connection of said second pair of contacts
or shocks have passed, after which the spring 34
and for permitting the free passage of air to the
will move the restraining means to the normal
shields and around the contacts and through said
position shown in Fig; 1 where it will permit the
top openings for extinguishing. the. are upon the
normal opening of the switch when desired.
opening of they switch, and means for actuating
Although a particular embodiment of this im
said movable insulating support for. closing and
provement has been shown and described; var~
opening the switch and for exposing fresh sur
ious modi?cations may be made therein for‘ faces of the. interior of said are shields to the ef
adaptation to particular requirements without
fects'of the arc during the separation of the en~
departing from thescope of the invention.
gaging contacts. by the-downward movement of
I claim:
said movable. insulating support in opening the
1. An electric switch comprising a?xed insu
switch.
lating support, a contact carried thereby and ex
4.. An electric switch comprising a ?xed'insu
tending downwardly therefrom, a vertically mov
lating support, a pair of contacts carried thereby
able insulating support ‘below said ?xed contact,
and extending downwardly therefrom, a movable
a contact carried by said movable insulatingsup
insulating
support, a pair of contacts connected
port and adapted to engage said ?rst named con
tact upon the upward movement of said movable 60 by a bridge and carried by the movable insulat
ing support for engaging the ?rst named pair of
insulating support, a vertically extending arc
contacts respectively upon the upward movement
shield surrounding and. spaced from said con
of the movable insulating support, a pair of are
tacts throughout the length of the shield and
shields of metal carried by-said movable insulat~
?xed at its lower end. to said movable insulating
support and having openings at both of its ends,
ing support and insulated thereby, each of said
said movable support having an opening opposite
shields having a top opening, said. shields. sur
the lower end of saidarc shield for the free pas~
rounding each pair of the engaging contacts re
sage of gasestherethrough and upward through
spectively and spaced therefrom throughout the
the space between the arc shield and the con
length. of each shield for providing» an interven
tacts for extinguishing the are upon the open- " ing. air space between. the shields and the con
ing of the switch, and the downward movement of
tacts. for permitting the free passage of gases
said insulating. support and of said are shield ex
from the arc therethrough, eachofsaid shields
posingfresh surfaces of the interior of said are
having a side opening opposite the side opening
shield to the elfectsof the arc during the/sepae
of
the other shield for. receiving the bridge cone
ration of the‘ contacts in the opening movement.
nection of said. second pair of contacts and for
2,407,716
13
permitting the free passage of air to the shields
and around the contacts and through said top
openings for extinguishing the are upon the open
ing of the switch, and means for actuating said
movable insulating support for closing and open
ing the switch and for exposing fresh surfaces
of the interior of said are shields to the effects
of the arc during the separation of the engag
ing contacts by the downward movement of said
movable insulating support in opening the switch.
FRANK G. LOGAN.
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