U.S. patent number 3,760,157 [Application Number 05/270,856] was granted by the patent office on 1973-09-18 for electrically heated window with a connector block and a circuit breaker.
This patent grant is currently assigned to Thermoseal Glass Corporation. Invention is credited to Irvin Newman, Roy Strengholt.
United States Patent |
3,760,157 |
Newman , et al. |
September 18, 1973 |
ELECTRICALLY HEATED WINDOW WITH A CONNECTOR BLOCK AND A CIRCUIT
BREAKER
Abstract
An electrically heated window including an insulated corner
gusset having an electrical lead extending therethrough to supply
electrical power to one sheet of a plurality of parallely-arranged
sheets of glass, one of which has been coated with an
electroconductive transparent coating, and from which the supply of
electrical power is removed upon a breakage of the glass sheet
having the electroconductive coating, thus avoiding the possibility
of an individual being subjected to an electrical shock by coming
into contact with the broken glass.
Inventors: |
Newman; Irvin (Cherry Hill,
NJ), Strengholt; Roy (Holland, MI) |
Assignee: |
Thermoseal Glass Corporation
(Camden, NJ)
|
Family
ID: |
23033090 |
Appl.
No.: |
05/270,856 |
Filed: |
July 11, 1972 |
Current U.S.
Class: |
219/522; 219/203;
219/504; 219/541; 219/501; 219/506; 219/509; 219/543 |
Current CPC
Class: |
F25D
21/04 (20130101); E06B 3/667 (20130101); H02H
5/10 (20130101); G08B 13/04 (20130101); H05B
3/84 (20130101); H05B 2203/016 (20130101) |
Current International
Class: |
F25D
21/00 (20060101); F25D 21/04 (20060101); G08B
13/04 (20060101); E06B 3/667 (20060101); H02H
5/10 (20060101); E06B 3/66 (20060101); H02H
5/00 (20060101); G08B 13/02 (20060101); H05B
3/84 (20060101); H05b 003/06 () |
Field of
Search: |
;219/203,501,504,506,509,511,522,541,543 |
References Cited
[Referenced By]
U.S. Patent Documents
Primary Examiner: Mayewsky; Volodymyr Y.
Claims
We claim:
1. An electrically heated window unit comprising spaced apart glass
panels, spacer means extending along the edges of said panels and
secured thereto, the internal face of one of said panels having an
electroconductive transparent coating thereon, spaced apart bus
bars in contact with said coating, corner gussets between the said
spaced apart said panels carrying leads for conducting electrical
current from a source of electrical energy to the said bus bars, an
electrical circuit including a circuit breaker having an electrical
current flow responsive electronic device and a starting push
button electrically shunting and adjusting said electronic device,
said electronic device shutting off the supply of electrical power
to said bus bars and electroconductive coating upon the breakage of
the panel having the said coating thereon.
2. The structure recited in claim 1 wherein said gusset comprises
an insulating block.
3. The structure recited in claim 1 wherein said circuit breaker
includes a visual signal to indicate when the electric power source
to said coated pane is shut off.
4. The structure recited in claim 1 wherein said circuit breaker
includes an adjustable potentiometer to adjust the circuit breaker
to the resistance of the electroconductive coating on the said
coated pane.
5. The structure recited in claim 1 wherein said corner gusset is
mitered to receive like mitered ends of a spacer extending between
the said spaced panes.
Description
BACKGROUND OF THE INVENTION
Electrically heated window units are in common usage, particularly
in cabinet structures which are refrigerated. Usually, such window
units comprise a plurality of sheets of glass arranged parallel to
one another with a space therebetween which can, when desired, be
evacuated to form a dead air space therebetween in order to improve
the insulating properties of the double-walled window unit. When
window units of this type are used in refrigerated cabinets, it is
desired to heat, in some manner, the sheet of glass which is
exposed to the room temperature so as to avoid the formation of
condensation thereon which would obstruct vision through the glass
unit. The obstruction of vision through the glass unit is most
undesirable, particularly where such glass units are employed in
refrigerated cabinets which contain therein items on display and it
is desirous that the customer have an unimpeded view of such
items.
In instances where an electrically heated pane of glass is employed
in the formation of a unit comprising a plurality of
parallely-arranged sheets of glass, some means must be provided for
shutting off the flow of electrical current to the glass when, for
any reason, the glass becomes broken, thus making possible the
shocking of anyone coming in contact with the broken pane of
glass.
Some attempts have been made to safeguard against such occurrences,
as shown, for example, in prior U.S. Pat. No. 3,379,859 and U.S.
Pat. No. 3,449,551. However, these prior safeguard methods are not
dependent upon the resistance offered by the electroconductive
coating on the sheet of glass which is electrically heated and thus
could, under certain conditions, fail to operate to cut off the
source of electrical power to the glass unit with ensuing
electrical shocking of one coming into contact with the broken
glass.
With the above in mind, it is the primary object of the invention
to provide for an automatic means designed to operate on the basis
of the electrical resistance offered by the electroconductive
coating on a sheet of glass to provide for the removal of the
source of electrical power to the glass in the event of a breakage
of such glass, thus obviating the electrical shocking of one coming
in contact with the broken glass.
Another object of the invention is to provide an improved means for
connecting some of the corners of the glass units with an
insulating corner gusset which has extending therethrough an
electrical lead which will furnish the electrical power for the
electroconductive coating on the sheet of glass.
Another object of the invention is to provide an electrically
heated, multiple sheet glass unit adapted particularly for use in
refrigerated units which will avoid the possibility of one being
subjected to an electrical shock upon the breakage of the glass
sheet having a coating of an electroconductive substance
thereon.
Still another object of the invention is to provide a molded corner
gusset made of a suitable insulating medium with an electrical lead
extending therethrough, one end of said electrical lead extending
to a suitable source of electrical supply and the other end of said
lead extending to a spring member which is in electrical contact
with an electroconductive coating extending over the surface of one
sheet of glass of a multiple glass sheet unit.
Another object of the invention is to provide a circuit breaker for
an electrically heated glass unit wherein a transistorized breaker
means is employed, thus making possible the adjustment of the
circuit breaker to operate at variable degrees of resistance
offered by the electroconductive coating on the glass which is
electrically heated, thus insuring the cut-off of power means
thereto upon a breakage of the coated glass unit.
Another object of the invention is to provide a means whereby a
signal lamp is employed to give a visual indication regarding the
working condition of the circuit breaker.
Other objects and advantages of the invention will become more
apparent during the course of the following description, when taken
in connection with the accompanying drawings, wherein like numerals
are employed to designate like parts throughout the same.
DESCRIPTION OF THE DRAWINGS
FIG. 1 is a perspective view of a multisheet glass unit constructed
in accordance with the present invention.
FIG. 2 is an enlarged view showing in more detail and with parts
broken away, the structure shown in FIG. 1 of the drawings.
FIG. 3 is a view taken on line 3--3 of FIG. 2, looking in the
direction of the arrows.
FIG. 4 is an enlarged view showing the corner gusset of the present
invention.
FIG. 5 is a modification of the corner gusset shown in FIG. 4.
FIG. 6 is a diagram of the electrical circuitry of the present
invention.
FIG. 7 is a view showing how all of the electrical components of
FIG. 6 can be assembled in one housing.
FIG. 8 is a view of one type of potentiometer showing how the same
may be mounted separately from the common housing shown in FIG.
7.
FIG. 9 is a front elevation view disclosing the potentiometer, push
button and neon indicator mounted in the framework surrounding the
multipane unit, and
FIG. 10 is a front elevation view showing how the neon indicator
only can be mounted on the framework of the multipane unit.
DESCRIPTION OF THE PREFERRED EMBODIMENTS
Referring now to the drawings, there is shown therein a multipane
unit 10, constructed in accordance with the teachings of the
subject invention. The unit 10, preferably, comprises two parallely
disposed panes 11 and 12 which can be of suitable thickness for the
intended purpose for the unit. The panes are of suitable dimension
and usually comprise clear glass so as to enable the same to be
used in conjunction with a cabinet or like structure, such cabinet
or like structure being adapted for the storage of food items
therein so as to enable a purchaser to observe the items within the
cabinet.
As can be appreciated, the parallely disposed panes 11 and 12 can
be mounted in a suitable framework so as to be incorporated in a
door, whether the same be one pivotally mounted in a suitable
opening formed in the cabinet or slidably retained in a suitable
trackway formed in the cabinet opening.
As seen more clearly in FIG. 3 of the drawings, panes 11 and 12 are
arranged in spaced relationship by means of a spacer element 13,
formed of metal or any other suitable material. The spacer 13
extends completely around the top, bottom and side walls of the
aforesaid unit 10, except that at the corners where electrical
leads are to be admitted into the space 14, the spacer is joined to
a corner gusset 15, which will be described with more particularity
hereinafter.
The spacer 13 is bonded to the glass panes 11 and 12 by means of a
suitable line of adhesive extending between the spacer and the
edges of the glass panes. A catalized polysulfide adhesive has been
found to be very effective in accomplishing this seal, although it
is apparent that other suitable adhesives could be employed for
effecting the bond between the spacer and the glass panes,
aforesaid.
The spacer 13 is formed with recessed areas 16 and 17, along one
edge thereof and a suitable filler material 18, extends therein to
further insure that the space 14, between the panes 11 and 12, will
be substantially airtight.
As is usual in the employment of an electrically heated unit,
constructed in accordance with the present invention, one pane
thereof is provided with an electroconductive coating 19, said
coating usually being applied thereon in any suitable manner. The
coating 19 is adhered to the glass pane 11, within the space 14, in
such a manner that when an electric current is supplied to the
film, as will be hereinafter explained, the film will be heated and
will, in turn, heat the glass panes 11 and 12.
Any type of electroconductive coating can be employed provided, of
course, the same meets the standards of transparency and
conductivity.
Referring now to FIG. 4 of the drawings, there is shown therein the
improved corner gusset of the present invention. The gusset may be
molded or otherwise formed of a suitable insulating material, and
comprises a substantially inverse L-shaped formation with the legs
of the L-shaped formation designed to be received within the ends
of the spacer bar and secured therein by a suitable adhesive.
As shown in dotted lines in FIG. 4 of the drawings, the spacer 13
extends over a portion of the said gusset 15 and abuts a ledge 20.
Similarly, a like spacer extends from the opposite leg of the
L-shaped formation and the same abuts a ledge 21, formed on this
portion of the gusset. An electrical lead 22 extends through the
insulator block forming the gusset and the same may be mounted
therein when the gusset is molded so as to insure an airtight
connection between these parts.
Surrounding the lead 22, interiorly of the space 14, is a grommet
23 which will assist in retaining the lead 22 in proper position
within the insulated corner gusset. Secured in electrical
connection with the electrical lead 22, is a spring-like member 24,
which is adapted to be in contact with a bus bar 25, which is
positioned inwardly of the edges of the pane 11, which has the
electroconductive coating thereon.
While I have described the manner of securing the gusset to but one
corner of the unit 10, it will be understood that a similar corner
gusset is mounted on the opposite edge of the unit so as to present
a like electrical connection to the bus bar 25 extending along the
other edge of the unit 10. Of course, the gusset at the opposite
edge of the unit 10 will function in the same manner as previously
described insofar as concerns the securing thereto of the spacers
13.
For that matter, and whenever found more desirable, the aforesaid
gusset formation may be employed at all of the corners of the unit.
Of course, only two such corner gussets need be formed with an
electrical lead extending therethrough, as previously described,
since it is only necessary that two electrical leads be in contact
with the aforesaid bus bars 25 in order to provide an operable
structure intended to prevent accidental electric shocking by the
breakage of the glass pane having the electroconductive coating
thereon. The manner in which this will be effected will be
described with more particularity hereafter.
Referring now more particularly to FIG. 5 of the drawings, there is
shown therein a modified type of corner gusset 15'. The gusset
shown therein is adapted to be employed where a mitered joint
connection is desirable between the gusset and the spacers 13'.
The gusset 15' is molded, or otherwise formed of a suitable
insulating material, and is of substantially L-shaped formation
with portions of the leg sections of the L-shaped formation being
of reduced cross section in order to enable the mitered ends of the
spacer bars 13' to be fitted thereover and adhesively, or
otherwise, secured thereto in any known manner.
The gusset shown in FIG. 5 is adapted to have the spring member 24'
secured thereto, as by molding the gusset of a suitable insulating
material and embedding one end of the spring member therein, as
shown in dotted lines in this Figure of the drawings.
An electrical lead, not shown, can be secured, in any known manner,
to the spring clip, as at 22', and lead to a suitable source of
electrical power.
Referring now to FIG. 6 of the drawings, there is shown therein a
diagram of the electrical components employed with the present
invention to provide a circuit breaker means which will be
responsive to the resistance offered by the electroconductive
coating on the coated pane of glass.
It should be pointed out at this time that the electrical
resistance offered by any glass pane which has been coated with an
electroconductive substance will vary from one pane to another.
This may result from any number of reasons; one such reason being
that it is almost impossible to apply a uniform coating of the
electroconductive substance to successive panes of glass. Thus, for
this reason alone, each such coated pane of glass will present
differing resistance characteristics and it is for this reason that
we have devised a circuit breaker which will be capable of
operating to cut off the flow of current to the coated pane,
notwithstanding the differing degree of resistance offered by any
such coated pane.
Shown in FIG. 6 of the drawings, are a pair of lead lines leading
to a suitable source of electrical power such as a conventional 115
V A. C. The circuit includes a wire-wound, fixed resistor 26; a
wire-wound potentiometer 27; a silicone diode 28; an electrolytic
capacitor 29; a carbon resistor 30; a push button 31; a triac 32,
and an indicator lamp 33.
In operation, the device is connected as shown in FIG. 6 of the
drawings. The input line leads from the power source and is
connected through suitable connectors to a fuse box, wall outlet or
the like. To set the device for operation for a glass pane having a
given resistance by reason of the electroconductive coating
thereon, the push button 31 is depressed, allowing current to flow
through the aforesaid electroconductive coating. When the push
button 31 is depressed, the indicator lamp 33 will light up,
indicating the application of power to the unit. Upon release of
the push button, the potentiometer 27 should be carefully adjusted
to the point where the indicator lamp 33 just stays on. This may
require the use of the push button more than once in order to
establish a threshold point of operation for a glass pane having a
given specific resistance.
Any change of more than 20 percent of the glass area, due to
cracking or breaking, will then reduce the amount of current drawn
through the triac 32. The lighter loading of the triac causes less
current to flow through the resistor 26 and potentiometer 27 to a
point less than that required to operate the triac 32. When this
occurs, the current flow ceases and the indicator lamp 32
extinguishes, thus giving a visual indication that the power is
off, thereby requiring a resetting of the unit by repeating the
threshold setting adjustment as described above.
The resistor 30 relieves the wattage power dissipation requirements
of the potentiometer 27, thus allowing a relatively small component
to be used. The diode rectifier 28 rectifies the a. c. voltage
tapped off the potentiometer 27 and the unsmoothed d. c. is
filtered by the capacitor 29. This d. c. voltage is then applied
through the current limiting gate control resistor 30 to the triac
gate. When the voltage at the triac gate is at a sufficient level
to initiate conduction, current will flow through the triac to the
lead and to the glass pane with the electroconductive coating.
All of the aforementioned electrical components, i.e., fixed
resistor 26, potentiometer 27, diode 28, capacitor 29, resistor 30,
push button 31, triac 32 and indicator lamp 33, may be housed in a
single container and placed at a position convenient for use,
preferably, although not necessarily, at a position in close
proximity to the glass to be heated. Such an arrangement of parts
is shown in FIG. 7 of the drawings.
In certain types of installations, it may be desirable to
disassociate the potentiometer from the remainder of the electrical
apparatus, although the same is still in circuit therewith. In such
cases, the same may be installed in a remote position from the
remainder of the components by means of a bracket 34. In another
type of installation, the indicator lamp 33 alone may be mounted on
the framing 35 surrounding the glass unit, with the remainder of
the electrical components mounted in a remote position from the
frame assembly, such as shown in FIG. 10 of the drawings.
In some instances, by reason of the frame design, the indicator
lamp 33, potentiometer 27 and push button 31, may all be mounted
thereon, as shown in FIG. 9 of the drawings.
It is to be understood that in any or all of the aforesaid manners
of installing the said components, the triac 32 must not be mounted
too close to the heat dissipating potentiometer 27 as the heat
derived therefrom would adversely affect the operation of the
triac.
As stated previously, the electrically heated glass pane is usually
on the room side of the cabinet and the aforesaid electrical
components are designed to obviate the shocking of anyone coming in
contact with a broken pane. As a further precaution, a microswitch
(not shown) can be installed on a door so as to remove the power
from the electroconductive coated pane when the door is opened.
This will prevent the shocking of anyone should, for any reason,
the inside or uncoated glass pane is broken and one could come in
contact with the coated pane.
Thus, it will be seen that we have provided a safety means for an
electrically heated glass pane which will insure that the power fed
thereto will be interrupted upon the breaking of a pane coated with
an electroconductive coating. It will also be seen that we have
provided for a novel means whereby the power directed to the
aforesaid coating is fed through electrical leads extending through
a corner gusset of novel construction.
It will be evident that many arrangements other than those shown
herein can be conceived within the scope of the invention,
depending upon the particular requirements.
* * * * *