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Патент USA US3024342

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March 6, 1962
Filed Nov. 16, 1959
2 Sheets-Sheet 1
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28 16
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March 6, 1962
Filed Nov. 16, 1959
2 Sheets-Sheet 2
/7 5632
KARL ,4. ?eA/vpm/ame
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Patented Mar. 6, 1962
Karl A. Brandenberg, Milwaukee, Wis., assignor t0
Square D Company, Detroit, Mich., a corporation of
Filed Nov. 16, 1959, Ser. No. 853,288
6 ?aims. (Cl. 200-159)
button pilot light switch having mating contact points
which make and break contact with a wiping action.
A further object of the invention is to produce a push
button pilot light switch in which the useful life thereof
is substatially increased over that of like prior devices.
A further object of the invention is to provide 1a push”
button pilot light switch that is simple and durable in
construction, e?icient and reliable in operation, and that
This invention relates to electrical switches, and more
is economical to produce.
particularly to an electrical switch adapted for use in 10
Brie?y, the foregoing objects are accomplished by the
conjunction with push-‘button pilot light devices used on
electrical instrument and control panels.
provision of the push-button pilot light switch having a
switch lever assembly pivotable to preselected contact
positions by the ‘actuating plunger arm of the push-button
pilot light. The switch includes a housing having an
Pilot lights are often used to monitor electrical circuits
and, when so used, are mounted on switch and control
panels remote from the devices to be monitored, with the 15 interior switch chamber therein. The switch lever assem
bly is pivotally mounted intermediate its ends in the
the electrical circuits of the monitored device. With this
chamber for rocking movement therein, with one end of
arrangement, either one of two types of failures will cause
the assembly being connected to the plunger such that
the lamp to become extinguished. The ?rst of these
reciprocation of the plunger will pivot the switch lever
failures is the interruption of the load current to the 20 assembly to predetermined switch contact positions. The
device to be monitored, this being the normal operation
switch lever assembly includes a pair of elongated ?exible
indicating lamps in such pilot lights being connected into
of the indicating lamp. In the second type of failure,
the ?lament of the indicating lamp may become burned
out and, in such event, the pilot light would not perform
spring members which are disposed in superimposed face
to face relation and retained together in such position at
a point intermediate the ends thereof by a suitable con
its required function of indicating a power failure to the 25 necting means. With this construction, the respective ends
monitored device.
of the ?exible spring members are free. At each end of
To alleviate this condition, conventional push-button
the lever assembly movable contact members are resili
pilot lights were developed. These pilot lights are con
ently clamped between the free ends of the spring mem—
structed such that when pressure is applied to the lens
has for limited pivotal movement therebetween. The
cap of the pilot light, a plunger arm is depressed which
construction is such that when the plunger pivots the
actuates an electrical switch which, in turn, establishes a
lever assembly to a contact position, the respective mova
test circuit, which is independent of the load circuit being
ble contact member which is clamped between the free
monitored, for testing the ?lament circuit of the lamp
ends of the spring members contacts an associated station
in the pilot light. With this arrangement, defects such as
ary contact in the switch chamber with a rocking, pivotal
a burned out pilot light lamp or a defective connection
action such that contact between such movable contact
between the pilot light lamp and its source of electrical
member and the stationary contact member is made with
power .are thus detected.
a wiping action.
One of the common sources of trouble in the use of
In one form of the invention, the spring members are
push-button pilot lights is the inadvertent failure of the
formed of a resilient material such as spring steel. How
electrical switch used in conjunction with the pilot light
ever, at least one of such spring members may be formed
mechanism. Because of the limited space requirements
of ‘a rigid material.
and long intervals of non-use, prior switches of this nature
Other objects and advantages of the invention will be
could not ‘be depended upon for effective and trouble-free
apparent from the following description taken in conjunc~
operation throughout the life of the switch.
A speci?c problem with such pilot light switches- is
the inadvertent fouling and pitting of the electrical contact
points therein. Such fouling may be caused by oxides
or foreign material. Pitting is caused by electrical arcs
occurring between the points of contact immediately upon
making and breaking contact, such arcing eating away
the contact points of the switch and causing premature
tion with the drawings, in which:
FIG. 1 is a front elevational view of a push-button pilot
light assembly having a pilot light switch constructed in
accordance with the invention;
FIG. 2 is an enlarged bottom plan view of the pilot
light switch with part thereof being shown in section, and
taken along the line 2——2 of FIG. 1;
FIG. 3 is an enlarged upright vertical sectional view of
the switch shown in FIG. 1, and showing the interior
It has been found that such arcing and the resultant
switch lever [assembly in one contact position, and is
pitting of the contact points can be substantially reduced
taken on line 3-3 of FIG. 2, part thereof being shown
if the contact points can be made to rub or wipe one over 55 in elevation;
the other upon making and breaking of contact. Such
FIG. 4 is a view similar to FIG. 3 but showing the
switch assembly in another contact position;
wiping action not only reduces arcing and pitting, thereby
FIG. 5 is a bottom plan View of the switch lever assem
substantially increasing the life of the switch, but also
bly shown in FIGS. 2, 3, and 4;
establishes a more ?rm contact of the contact points to
failure of the same.
effect a more positive electrical connection therebetween.
However, because of the space limitations, it has been
impractical and unduly expensive hereto-fore to incorpo
rate such wiping action into a pilot light push-button
It is an object of the present invention to provide a
push-button pilot light switch that is positive in action
and dependable in use.
A further ‘object of the invention is to provide a push
FIG. 6 is a side elevational view of the switch lever
assembly shown in FIG. 5;
FIG. 7 is a bottom plan view of the modi?ed form of
the switch assembly shown in FIG. 5 ; and
FIG. 8 is a side elevational view of the switch lever
assembly shown in FIG. 7.
Although the invention is shown and described here
in with reference to a switch adapted for use with a
push-button pilot light assembly, it will be understood
that the invention may be employed with any type of
button pilot light switch in which the pitting and fouling
70 device requiring an electrical switch actuated by a re
of the contact points therein is substantially reduced.
ciprocable plunger, such as a lever arm, push button, or
A further object of the invention is to provide a push
the like.
is pivotally mounted within the chamber 24 by means of
pivot engaging means in the form of the spaced ears 52
and 54 on the spring member 34, such ears being loose
ly received at their ends in notches 52a and 54a in the
housing and rockably mounted between the ridges 56
and 57 in the respective housing halves. Such rocking
pivotal movement of the switch assembly is ?atwisc or
Referring to FIG. I, there is shown a pilot light mech
anism, generally designated at P, and having at its lower
end a pilot light switch S constructed in accordance with
the invention. A transformer T is interposed between
the pilot light and the switch S and functions to supply
suitable electric current to the lamp in the pilot light.
The pilot light P is of conventional construction and
in a direction generally normal to the faces of the as
includes a base 10 having a lens or color cap 12 recip
rocably mounted on the base by means of the ring nut
14, there being an interior, axially-shiftable, upwardly
biased sleeve (not shown) which normally retains the
color cap in an upwardly biased position, as shown. To
establish the ?lament test circuit heretofore mentioned,
Pivotal movement of the assembly A is effected by
movable means which, in the form illustrated, is the
plunger 16. The plunger 16 has a semi-circular notch
60 for connectably receiving the right end portion of the
switch assembly A. In the preferred form, the mem
the color cap 12 is depressed and causes the sleeve to
ber 32 has an outer extending portion 62 which is re
move downwardly which, in turn, e?iects downward 15 ceived in the notch 60 to form the connection between
movement of the arm or plunger 16, such plunger there
the plunger and the switch assembly. If the switch S
by actuating the switch S to preselected switch contact
positions in a manner to be described. Speci?c struc
tural details of the pilot light are set forth in the co
pending US. patent application of Earl F. Mekelburg,
Serial No. 702,940, ?led December 16, 1957, and are
not described herein since such structure forms no part
of the present invention.
Selective switching from the monitored circuit to the
?lament test circuit and back again is effected by the
switch S, now to be described, and which is substituted
for the switch in the above copending application. The
switch S includes a housing formed of two coacting mat
ing halves 20 and 22 (FIG. 3) which, when joined to
is to be used independently of the pilot light P, the
plunger 16 may be replaced by any like actuating rod
or plunger, such as a conventional reciprocable push
button having a notch similar to the notch 60 for re
ceiving therein the end of the assembly A.
Interposed in the path of the respective movable con
tacts on the assembly A for contact therewith are the
stationary contacts 70, 71, 72, and '73, which may be
secured in the respective housing halves by any suitable
attaching means such as the threaded stud 75 shown in
FIG. 3.
In operation, as the plunger 16 is displaced to its low
er position, contact between the movable contact 42 and
gether, form an interior switch chamber 24. The halves 30 the stationary contact 73 is broken and contact between
20 and 22 may be retained together by any suitable
the movable contact 40 and the stationary contact 71
means such as the screws 26 (FIG. 2), such screws ex
is established, as shown in FIG. 4. When the plunger
tending upwardly and being threadedly secured in the
returns to its upper position, the movable contact 4-3 and
pilot light base 10. The mated halves 20 and 22 form
the stationary contact 71 break contact, while contact is
also a bore 28 in which the pilot light arm or plunger
established between the stationary contact 73 and the
16 is received for reciprocable translating motion there
movable contact 42.
in. The housing half 20 contains a recess 27 in its up
It will be noted that, as a result of the manner of
per surface for receiving a portion of the transformer T.
mounting the movable contacts 40 and 42 between the
Pivotally mounted within the chamber 24 is a switch
leaf members, the movable contacts make and break
operating lever assembly, generally designated as A, with
contact with the respective stationary contacts with a
which the present invention is particularly concerned.
The assembly A includes a pair of elongated leaf mem
bers 32 and 34 joined in ?atwise face to face relation
and retained in such relation by suitable connecting
means, such as the rivet 36, with the respective opposed
ends of the spring members being free and unattached.
One or both of the members are resilient, ?exible leaf
springs. In the form illustrated in FIGS. 1 through 6,
wiping action by rocking ?atwise from their normal
clamped position between the respective free ends of
the spring members 32 and 34. Such rocking action
results in su?icient rubbing or wiping action of the mov
able contaots over the stationary contacts when contact
therebetween is established or interrupted to alleviate
the fouling and pitting of the contact points.
A modi?cation of the switch lever assembly A is shown
the member 34 is made of a suitable resilient material
in FIGS. 7 and 8, wherein each of the members 80 and
such as, for example, spring steel having suitable flexure 50 82 are formed of a resilient ?exible material, such as
characteristics, with the member 32 being formed of a
spring steel, the members being joined intermediate their
relatively stiff and non-flexible material. Resiliently
ends by the rivet 84. U-shaped movable contacts 86 and
clamped at each end of the assembly A between the re
88 are clamped between the respective free ends of the
spective free ends of the spring members 32 and 34,
spring members 80 and 82 in the same manner hereto
for rocking movement ?atwise, are the U-shaped bridg
fore described with respect to the contacts 40 and 42 of
ing or movable contacts 40 and 42 of electrical conduct
the assembly A. By forming both of the spring members
ing material. With this construction, the contacts 40
80 and 82 of a resilient material, effective ?exibility in
and 42 are free to rock flatwise substantially universal
the wiping action at the time of contact between the mov—
ly in their clamped position between the free ends of
the spring members. To prevent the contacts 40 and 60 able and stationary contacts is obtained.
Having thus described my invention, I claim:
42 from slipping out of such clamped position and from
1. An electrical switch mechanism adapted for use with
rocking appreciably edgewise, the member 32 is pro
a push-button pilot light of the type having a reciprocable
vided with constraining means in the form of retaining
plunger arm for actuating the switch whereby the arm
tabs 44 and 45 for the member 40 and tabs 46 and 47
is reciprocable to switch contacting positions in response
for the member 42. The tabs are loosely received in
pressure applied to the lens cap of the pilot light, said
aligned apertures in the respective movable contacts,
switch mechanism comprising a housing having an interor
thereby allowing flatwise rocking action of the contact
switch chamber therein, at least one stationary contact
member, yet preventing edgewise movement in any di
member disposed in said chamber, an elongated switch
rection from such clamped position. The outer portion
lever assembly pivotally mounted intermediate it ends
of the arms of the U-shaped contact 40 are silver-tipped,
to form good electrical contacts, as indicated at 4011
and 40b, while the outer portion of the arms of the U
shaped contact 42 are silver-tipped to form good con
tacts, as indicated at 42:: and 42b.
In the present instance, the switch lever assembly A
in the chamber for rocking movement in a direction gen
erally normal to the faces of the assembly about a ?rst
axis extending transversely of the lever, one end of the
assembly being connected to the plunger so that recipro
cation of the plunger pivots the switch lever assembly to
predetermined switch contact positions about said axis,
said switch lever assembly compriing a pair of elongated
movable members disposed in ?atwise face to face rela
tion, at least one of said members being a leaf spring,
and connecting means retaining the members together in
such face to face position at a point intermediate their
ends, and a movable contact disposed at at least one end
followed by continued rocking of the members about the
?rst axis in said one direction, the movable contact is
caused to rock about said second axis, and the contact
portions of the movable contact are caused thereby to
wipe the contact portions of the complementary contact.
4. The structure according to claim 3 wherein the other
of the members is rigid, and the movable means en
gages the rigid one of the members for so rocking the
of the assembly and positioned for contact with the sta
tionary contact member when the assembly is pivoted to
one of its contact positions, said movable contact being
5. The structure according to claim 3 wherein both of
resiliently clamped between the free ends of the members 10 said
members are resilient.
for ?atwise rocking movement therebetween against the
6. An electrical switch mechanism comprising two
clamping pressure of the free ends of the members about
elongated leaf members in ?atwise facing relation to each
axes parallel to said ?rst axis, respectively, whereby
other, at least one of said members being resiliently ?ex
the movable contact member slides over the stationary
?atwise toward and away from the other, means
contact with a wiping action when contact therebetween 15 ible
engaging the members intermediate their ends and sup
is established or interrupted.
porting them for ?atwise rocking substantially as a unit
2. A switch according to claim 1 wherein there are a
about a ?rst axis extending transversely of the members,
plurality of stationary contacts disposed in the chamber
a contact disposed at one end of the members between
faces and resiliently clamped therebetween by the
having its base portion clamped resiliently between the
resilient one of the members, means constraining the
members and having contact portions on the outer por
and said movable contact member is a U-shaped member
contact from displacement edgewise of the members from
tions of such U-shape adapted for contacting certain of
between the members while permitting the contact to rock
said stationary contact members.
?atwise of the members about a second axis extending
3. A switch mechanism comprising a body, two elon
gated members carried by the body, means engaging the 25 parallel to the ?rst axis in opposition to clamping pres
sure of the members, said contact being a U-shaped mem
members between their ends and supporting the members
her having its base portion clamped resiliently between
in face to face relation to each other for concurrent rock
said ?rst mentioned members and having contact portions
ing ?atwise substantially as a unit about a ?rst axis ex
tending transversely of the members, at least one of said 30 spaced endwise of the members from said second axis,
a stationary contact in the body having contact portions
members being resiliently ?exible ?atwise at at least one
disposed in the path of movement of the contact portions,
end portion for yieldable relative movement toward and
respectively, of the movable contact for engagement by
away from the adjacent end portion of the other member
movable contact portions as the movable contact
in the rocking direction, a contact disposed between the
members at said end portions of the members and resil 35 moves with said members in one direction, whereby upon
engagement of the contact portions of the movable con
iently clamped therebetween by the resilient one of the
with those of the stationary contact followed by con
members for rocking relative to the members about a sec
tinued rocking of the members about the ?rst axis in said
ond axis parallel to and spaced from said ?rst axis, means
one direction, the movable contact is caused to rock about
constraining the contact from displacement from be
tween the members while permitting the contact to rock 40 said second axis and cause its contact portions to wipe
across the contact portions of the stationary contact, and
about said second axis in opposition to the clamping pres
movable means engaging the other one of the members
sure of the members, movable means for rocking the
for rocking the members.
members, said movable contact having contact portions
spaced endwise of the members from said second axis,
a complementary contact carried by the body and having 45
contact portions disposed in the path de?ned by the mov
able contact portions as the movable contact rocks with
said members about said ?rst axis in one direction, where
by upon engagement of the complementary contact por
tions of the movable contact and complementary contact 50
References Cited in the ?le of this patent
Runner ______________ __ Nov. 19, 1935
France ______________ __ July 23, 1934
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