United States Patent
[19]
Newman et al.
[54]
GLASS PANEL CIRCUIT BREAKER
[75]
Inventors: Irvin Newman, Cherry Hill; Michael
G_ Kelly, Turnersvme, both of NJ.
.
[73] Assrgnee: Ira W. Fine, Pennsauken, NJ. ; a
part interest
[22] Filed:
Apr‘ 7’ 1975
[21] Appl. No.: 565,634
3,892,947
_
7/1975
[111
3,941,975
[45]
Mar. 2, 1976
Strengholt ......................... .. 219/522
_
Primary Exammer-Yolodymyr Y. Mayewsky
Attorney, Agent, or Fzrm-Howson and Howson
[ 57]
ABSTRACT
A frangible panel having an electrically-energizable
layer carried in an area thereof for heating the panel
.
.
and main circuit means for supplying electrical power
' Relfneq US‘ Application Data
to the layer is provided with circuit breaker means op
[63] commuano?-m-pa? of Ser- NO- 446,429- Feb- 27'
‘974- Pat' No' 3’876'862-
erable to interrupt electrical power to the layer upon
breakage of the panel. The circuit breaker means in
cludes a fusible link connected in series with the layer
and a solid-state control device connected in the main
circuit in parallel with the layer. The solid-state device
[52]
Cl‘ """"""" " 219/509; 219/203; 221199055242;
9
[51] Ilit. Cl.'.S..................... ,. H0593 l/02; “058 3/06
has a control gate which is connected to a Sensing cir_
[58]
cuit surrounding the electrically~energi2ablelayer and
which is connected in the main circuit to render the
held of each """"" " 219/ '02’ 203’ 509* 511’
219/522’ 541’ 543
_
solid-state control device non-conductive as long as
[56]
References C'ted
UNITED STATES PATENTS
the sensing strip is continuous and to render the solid
state control device conductive when the sensing cir
3,449,55l
3,475,594
3,526,753
6/1969
10/1969
9/1970
Aisamich .......................... .. 219/511
Aisamich ................... .. 219/509
Aisamich et al. ................. .. 219/522
cuit is broken- Thus, the solid-state control device
connects the fusible link to ground and causes the link
to blow, thereby interrupting power to the electrically
Newman et al ................... ..
energized layer_
3,800.l2l
3/1974
Dean et al. ....................... .. 2l9/202
3,876,862
4/1975
Newman et al ................... .. 219/509
_
4 Claims, 1 Drawing Figure
US. Patent
I
7
March '2, 1976
3,941,975
»
///6
A;
//7
//
3,941,975
. bus-_1~3.-.~an'd ‘to; ground; c'ausi‘ng'ithe ‘layer I'lto generate
V
heat for.heatinglth'é-plan‘eli Atypical layer has an impe
GLAS‘S PANEL CIRCULTBREAKER : -.
, The present application-is a-eOntinuatiQn-impart of
dance between bus?'bars'of aboutl 30-180 ohms'. As a
resu'lt,'a currentz?ow of aboutv l ampere can be’ ex
our_c,opending application‘Ser.,No¢446,4»29;.filed Feb.
27,1974, now US. Pat. No. 3,8'_7,§,8,6,2."~ ,
V_-_The present invention relatesjvto electrically-ener
gized glasspanels; andstmvlore:particularly, the-present
5 pected to‘ ?owithroughlayer l1-.
‘I '
' '
. .. For a more detaileddiscussion as’itb theistru'eture and
roper'ation- of .this type of panel,--referen'ee*is made to our
U.S:;Pat.=-No: 3,876,862- issued on ‘Apr? 8,1975, the
disclosure of which-ishereby incorporated herein.
.invention relates toteircuitbreaker means for interrupt
ing power 'toa frangiblewpaneljn the event it breaks. ,
.i‘lnour, aforementioned; patent, there are disclosed,
‘yarious embodiment/sot‘ an inyentjonjwhichzoperates to
In accordance with the presentinvention,highly safe
yet‘simple circuitebreaker means is provided toiiinter
ruptpower tp'ithe electrically-'energ‘izable"layer; 11 vin
interruptzypogwerkto an electrically-cuergizedrlayer on a
'g'lassrp'anelin‘the'eyent the panel breaks'pr becomes
cracked. ‘ The various embodiments include ;,circuit
breaker m'eahs‘jcontrolled a "solid-stiz'iteldeyiceicomv
- bus- Y12, and: hence ‘the 'la:yer>l1,*in the main circuit
'agro'und't'he ‘areaQWYhen conti'nuity'of the strip'is broken,‘
to the high voltage bus 12 and a low voltage lead. or
the event the panel 10 breaks. To this end, a fusible-link
or~fuse114 ilsdconnected in series-with the high—v‘oltage
Lnecte‘d 'to' a ‘sensing circuits‘trip partied-entire ‘panel
whichzincludes a'high-voltage supply lead 15 connected
‘amendment when the p'ahelw'isfc'iaclied' or broken,
vthev solid-state device is rendered‘ nod-‘conductive,
ground 1.6connectéd to'the groundbus13. Breakage
sensing circuitmeans 17 in the form'of1a thin elongated '
‘thereby in'te‘rriipti’ngj?ower t‘o'the panelsAlthough the
apparatus'discl'osed?ini"our patent operates entirely
satisfadtorily‘and safelyfthere exists anéedfo‘r‘apparaQ'
strip ,is'providedon the panel 10 to 'sense'ibrea'kage of
the panel “11) andtoactuate control means‘. 18 to‘ pro
vide-ta‘low-impedance shunt-around the‘layer 11 and
tus‘proViding ‘an even‘great‘er margin of safety.” ' i
‘ With‘ the‘fo'r'e'goingin‘irnind, vit is a primary object of
downstream of the fusible link 14. The sensing circuit
means; 17,; cooperates :with ;the"control.»means l'8'lto
the present invention ‘to provide’an electrically-ener 25: . render; the same nonaconduc'tive .asi'long asthev ‘sensing
‘giZed glass panel having an improved circuit breaker" circuit 17 is continuous; however, if the panel breaks,
and breakage-sensing arrangement which operates with
continuity of the sensing "circuit means-'17 "iszinter-i
thefhigh'est degree of safety“ a
» Another object of the present invention :is to provide
‘ acompletely fail-safe'system for interrupting power to
rupted, and the controlmeans .1181. iswactuatedi to sub
stantially short-circuit the fusible link 14. Asazresult,
'1 the, link 14 blowsand power to'the busrli~2and hen'c‘eito
antelectrically-energized glass panel~in~ the ‘ event 0
breakage of the panel.
a’
the layer 11.is‘therebyinterruptedThe fusible'link 14
is sized to carry,the.current> normally ?owing through
the layer_.1,l-. Since-‘suchpurre'ntis about l'ampere for
atypical panela~fuse~14<having a capacity, without
- Morespecificallyrin thepresent invention,- antelectri
cally,_energizable1 layer carried-iman area of a-frangible
panel is supplied ‘yvith;.el_e_ctrical energybymain circuit’
means'which includesarpair ofparallel bus bars carried
35 blowing, , of v v1 55,, ampereswould :be provided; The. fuse‘
M'shouldalso be ofthe ‘ifast;blow”,type.=~ -'
>
on, the,;panel.-_.A' fusible, link isycqnnected'in series‘with -
)ln theupresenteinstance,.thewntrolmeans 18 is pro-1
the ,v'high-yoltageg bus», bar-,Zand;v a-:sol_id,_.-,sta,te .-de_vice is
vided by~a.,S9.1:id-state’ device such;as a conventional'
connected in- parallel with, the layewracromssthe bus bars.
silicon controlrecti?ert SCR).,.-'l7he.;anode"of the/SCR
The solid-statedevicethas;apcoptgol ,gate which Wiscon
40. l§,is¢.connected_,to,'a'terminal‘20downstream .of the \
nected torthe. ]ow3yoltagebus7bar;by meansnf-a contin- . fusiblelinkhl?. The cathode of 'SCR‘ 18,. is connected to
uousfsensing circuit extendinglgaround ‘theldayer. The arrelatively low impedance» resistor 21-10 the ground '
gate isvalso connected to.thejhigh?oltagepus,through
a hightéimpedance ,resistor._ The sensing. circgit “renders
connected- toya,terminal-..'22,-;and/a high-impedance the solid-statedev'ice gnonyconductiyelas long as the , 45 .resistor. 23 connects ‘the terminal 22 to .aterminal24, in ‘
sensing circuit is continuous‘ a'rid. renders the'solid-state
the,high.;voltage_,supply line 15-. One end .l7awof the a
device conductive when the sensing circuit is inter
rupted, such as when the panel is broken. As a result,
the solid-state device substantially short-circuits the
bus bars to blow the fusible link and thereby to inter
rupt power to the layers on the panel.
These and other objects, features and advantages of
the present invention should become apparent from the
sensing circuit strip is connected to the low-voltage
ground bus 13 or lead 16.
Preferably, the low impedance resistor 21 has a value
. of about 5 ohms, so that when connected across the
main circuit 15 and 16, current ?ow through the fuse
l4 exceeds its capacity, causing the fuse 14 to blow. Of
course, the low-impedance resistor 21 also protects the
following description when taken in conjunction with
SCR 18 against excessive current when the SCR 18 is
the accompanying drawing which illustrates schemati 55 u-gated. The value of the low-impedance resistor 21 is
cally a frangible panel having the improved breakage
substantially lower than the resistance of the layer 11.
sensing and circuit breaker means of the present inven
In operation, alternating current power ( l20 V.A.C.)
tron.
supplied to the main circuit means causes electrical
Referring now to the drawings, the numeral 10 indi
cates schematically a frangible panel of glass or other
current to flow through the resistance layer 11 from the
high-voltage bus 12 to the low-voltage bus 13. At the
same time, full power is supplied to the anode of the
SCR l8, and a very low voltage is supplied to the gate
material. A layer of electrically resistive material 11 is
secured to the panel 10 in copolanar relation, and
power is supplied to the layer 11' by a pair of parallel
60.
through the high-impedance resistor 24. The gate of
bus bars 12 and 13 carried on the panel 10 in electrical
contact with the layer 11. The bus bar 12 is the high
voltage or hot bus, and the bus bar 13 is the low-voltage
or ground bus. Thus, electrical energy supplied to the
high-voltage bus 12 flows through the layer 11 to the
the SCR 18 is connected to the ground lead 16 through
65.v
the very low-impedance sensing strip 17 so that the
voltage supplied to the gate of the SCR 18 is exceed
ingly low and not of sufficient magnitude to cause it to
conduct. In the event the strip 17 becomes broken,
3,941,975
however, such as when the panel 10 breaks,ta‘positive
voltage sufficient to activate the SCR isgapplied to the
said control means including a solid-state device con
gate of the,SCR 18 through the'highdmpedance resis
with said electrically-energizable layer and in series
tor 23. As .a result, the SC'R conducts and provides a
low-impedance shunt across the'layer 11. This causes
with said fusible link, said solid-state device having gate
means operable to render said solid state control device
the fusible link» 14 to blow, thereby interrupting the
powertothe high-voltage bus -l_2 and hence to the layer
selectively conductive and non-conductive, and means
electrically connecting one end of said sensing circuit
11. Thus, in the event that a person'were to contact the
strip to said gate means and the upper voltage lead and
means electrically connecting the other end of said
10 sensing circuit strip to' the lower voltage lead in said
nected in said main circuit means in parallel relation
panel after it has been broken, the person would not
receive an electrical shock.
‘
'Whilejthe disclosed circuit breaker means has been‘
main circuit means to maintain said solid-state control
described in combination with a sensing strip'com
pletely_.-surrounding an electrically~energizable layer, itv
is"_cont_emplated that any one of the sensing strips and
strip is continuous and to cause said solid-state control
breaker mounting arrangements disclosed in our afore
cuit strip is interrupted, ‘whereby the solid state control
device non-conductive so long as said sensing circuit
device to conduct when continuity of said sensing cir
mentioned patent vmay-be utilized satisfactorily there-'
with._
-
a
-
>
device shunts the electrically-energizable layeriand.
1
blows theffu'sible link to interrupt power to the electri
in view ,of the foregoing, it should be apparent that
cally-energizable layer, 7
there has now been provided a highly safe'and effective
2. Apparatus according toclaim lwwherein said solid
circuitv breakerand sensing circuit arrangement for use 20 state control device conducts electricity upon applica
in combination'with electrically energized glass panels tion of a positive voltage to‘said, gate means, and said
to interrupt power to thepanels in'the‘event of break
' means electrically connectingsaid gate m'eans't'o‘ said"
age. ,
v,
t
:- j
'
’
upper voltage level lead includes a resistor having a
While a preferred embodiment of the present inven
high impedance relative to the impedance of said fran-‘
tion has, been described in detail, various modi?cations, 25 gible
sensing strip between said gate means and said
alterationsor changes may be made without departing
low voltage level lead, so that said strip normally applys ' ‘'
voltage at substantially said lower voltage level to said '
from the spirit and‘scope- of the present invention as
de?ned in the appended claims;
'
gatevuntil said stripvis interrupted, whereby a positive
tlgtln‘combination with a frangible panel having an '30 voltage is applied to the gate means to render the solid
state control device conductive for blowing the fusible
electrically-energizable layer secured thereto in copla
We claim: »
'7
,
link.
3. Apparatus according to claim 2 wherein said solid
state control device includes a silicon control recti?er
narjrelation and main circuit means having'upper and
lower voltage level leads for supplying electrical power
to said, layer, the improvement comprising: circuit
breaker means connected in said main circuit vfor inter 35 having its anode electrically connected to said upper
voltage lead, and its cathode ‘connected to said lower
rupting electrical power to said electrically-energizable
layerupon breakage of said panel, electrically-actuated
voltage lead through another resistor having an'impe
control means operable tocause said breaker means to
dance substantially lower 'than‘the impedance of said
conduct electricitywhen said main circuit means is
layer across said upper’ and lower voltage leads.
energized, andva' frangible sensing circuit strip'carried 40
4. Apparatus according to claim 3 wherein said fus~
ible link ‘has-a current-carrying capacity sufficient to
by said'panel and extending around a‘ substantial por
tion of ;_said electrically-energizable layer to detect
breakage of said ‘panel, said circuit breaker means in
carry current to said energizable layer during normal
operation thereof-'- but insufficient to carry current
through said solid-state device and said another resistor
cluding a fusible link connected inv series with said
upper’vloltage lead insaid main circuit‘means and'in'
series relation with said electrically-energizable layer,
’ ‘
45
when activated upon breakage of said sensing strip.
*
55
65
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18
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