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Патент USA US3039048

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June 12‘, 1962
G. A. WEIBLE
ELECTRONIC DOOR OPENING DEVICE
Filed March 15, 1961
3,039,038
60
I36
I32
26
INVENTOR.
BY
GEORGE A. WEIBLE '
WILSON, SETTLE 8: CRAIG
ATTORNEYS '
United States ‘Patent ()?lice
Patented June 12, 1962
1
2
3,039,038
ELECTRONIC DOOR OPENING DEVICE
George A. Weible, Detroit, Mich., assignor to Industrial
Electronics
Inc., Detroit,
ichigan
‘elm, a' corporation of
Filed Mar. 15, 1961, Ser. No. 95,972
7 Claims. (Cl. 318—478)
tional devices have comprised a plurality of Interlocking 15'
relays which operate to control a motor to open and close
'
‘
While such conventional
devices have in general operated satisfactorily, the use of
a plurality of relays has made the devices relatively ex
pensive and the service life has been relatively short be
cause of rapid deterioration of the relays.
the result that safety switch 24 remains open.
Power is supplied from a suitable source 26 to the
primary coil ‘28 of transformer 30. The transformer 30
25 is shown as having an iron core 32. A lead 34 extends
from one side of the transformer secondary coil 36 and
and durable electronic components.
Another object of the invention is to provide a door
30
opening device having only one relay, thus permitting
the use of a high quality relay having a longer life while
opening device having switches operated by pe sons ap
35
proaching the doorway, the switches being low-current
devices to insure the safety of the users.
Another object of the invention is to provide a door
opening device with an extended service life.
‘a second set of contacts 66
which form part of the present control circuit. The recti
?er 56 provides a pulsating D.C. curren to operate the
coil. The function of the capacitor 50 is to smooth the
Other objects of this invention will appear in the follow
responding parts in the several views.
In the drawings:
45 ter to the transistor base 68. The emitter to base current
FIGURE 1 is a view in perspective of a door construc
is controlled by the approach switch 22 and a second con
trol transistor 7 0.
tion operated by the door opening device of the present
invention;
FIGURE 2 is a schematic view of one embodiment of
the electrical circuitry of the present invention; and
50
FIGURE 3 is a schematic view of the circuit controlled
by the FIGURE 2 device.
55
being practiced or carried out in various ways. Also, it
is to beunderstood that the phraseology or terminology
employed herein is for the purpose of description and not 60
of limitation.
'
FIGURE 1 illustrates a typical door structure 10 which
is operated to open and close by means of the present
invention.
'
lead 96 which extends from the base 98 and has a branch
v65 100 with resistor 102 which connects with the lead 60 to
depressible panels 20, 21 which operate, when stepped 70
on, to close a switch positioned thereunder.
In operation, a person approaching the “in” door from
70 to conduct, permitting power transistor 44 to conduct
and energize relay coil 52 to open the door.
In the above described circuit, resistor 74 acts to limit
the current drawn by transistor 44, resistor 76 is a load
resistor for a diode 104, the light 88 and resistor 90 form
part of, a test circuit, and the resistor 102is a biasing re
3,039,038
sistor for the control transistor 70. A biasing resistor 1016
is connected by lead 108 from the base 68 of the power
transistor 44 to the lead 34 which connects to the second
will not open if switch 24 is closed before closure of
switch
22. 22 is closed subsequent to closure of switch
If switch
24, the door will still not open. It will be noted that a
resistor 140 is connected by lead 142 between the control
ary transformer coil 36.
transistor base 98 and lead 132. Resistor 140 is selected
When relay coil 52 is energized, it will close its normal
with a value to bias the transistor 70 to cutoff and prevent
ly open contacts 62 and 66. Referring to FIGURE 3, the
operation of this transistor. Thus, both potential paths,
contacts 62 comprise a pair of contacts 110, 112 to provide
through transistor 70 and through relay contacts 66, are
a double break switching action. The double break re
duces arcing on opening and results in less contact wear. 10 open preventing conduction by transistor 44. In view of
the fact that transistor 44 must conduct before relay coil
Closing of the contacts 62 closes a circuit between leads
52 will be energized, it will be appreciated that the door
114, 116. Lead 114 connects to the motor 64. A lead
will not open under these circumstances.
118 extends from the motor to a source of power 120.
An alternate method of operating transistor 44 is pro- '
The lead 116 is connected to the other side of power 120.
vided for the case where it is desired to permanently hold
It will thus be seen that closing of contacts 62 is effective
the door open. This might be desired, for example, on
to energize the motor '64 to open the door. Other control
warm summer days. In this circuit, the base 168 is con
components may be provided in this circuit to control
nected to power via lead 72, resistors 74, 76, lead 144,
such factors as the rate of door opening and the extent
resistor 146, lead 148, switch 150, and lead 152 which ’
of door movemen .
After the door has opened, the person entering will step 20 connects to lead 60 and thence to the secondary coil 36.
As will be appreciated closure of switch 150 will complete
oif the approach mat to pass through the door opening.
this circuit and excite the transistor 44 to ‘cause opening
In so doing, he will release approach switch ‘22 which
of the door. The door will remain open until switch 150
will immediately open. Means thus have to be provided
to hold the door open for a long enough period to permit
is again opened.
,
’
the person to walk through and off the safety mat 18‘. 25 A test circuit is ‘also provided for trouble shooting the
device
when
it
fails
to
perform.
The
most
frequent
This is accomplished in two steps. First means are pro
problem
encountered
in
service
is
the
shorting
out
of the
vided to hold the door open for a limited time with both
switches ‘22, 24. This may occur because’ the switches
switches 22 and 24 open. When switch 24 is closed subse
stick in the closed position or foreign material of a con
quent to the closing of switch 22, second means are pro
vided to hold the door open for as long as switch 22 is 30 ducting nature may ,cause such shorting. The test cir
cuit comprises normally open test switch 154 having a
Lead 158 ex?
closed.
contact point 156 connected to lead 34.
The means for holding the door open when both
tends from switch 154 into connection with lead 148
switches 22, 24 are open comprise an electrolytic capaci
which, as previously mentioned, is connected to lead 78.
tor 122 and the diode 104. Lead 124 extends from the
146 has a lo resistance. The closure of switch
capacitor 122 into connection with the lead 46 which eX 35 Resistor
154
places
resistor 146 in parallel with resistors 74, 76,
tends from the transistor collector 48. A second lead 126
and 106. The net resistance of this network is relatively
extends from the other side of the capacitor 122 into con~
low, permitting the flow of a relatively high current therenection with lead 72 between the resistors 7 4, '76. Lead
through. This current is high enough to' cause lighting
128 connects the diode 104 between leads 126 and 46.
of lights 88, 1318 if the respective switches 22, 24 are
The function of diode 104 is to prevent application of a 40 closed. Such closure, could, as previously mentioned, be
reverse voltage on the capacitor 122, which would cause
excessive wear on the capacitor. In essence, the diode
shorts out the capacitor during one half cycle. When
switch 22 is opened, capacitor 122 will keep the power
transistor 44 in conduction for approximately one and
one~half seconds. ‘Continued conduction by transistor 44
will keep the relay coil ‘52 energized and the door will
remain
Afteropen.
the elapse of one and one-half seconds, transistor
due to a short or sticking of the switch.
136 are provided in parallel with the lights in order to'
keep the circuits closed in the event the lights burnout.
If light 88 lights, then it may be assumed that switch
22 is shorted. If light 138 lights, then it may be assumed
that switch 24 is shorted. If neither light lights, the
service man may close switch 22. If the door does not
open but light 88 lights, then it can be assumed that the
problem is in the transistor 44 circuit. If this is the
44 would cease to function. However, by this time it is
case, the field can be further narrowed by subsequently
50
assumed that the person will have traveled through the
closing switch 24. If light 138 then goes on, transistor
door opening and will have depressed safety panel 21 to
44 and the relay are operating properly. The trouble is
close switch 24. Closing of switch 24 will close a second
then in the control circuit operating the motor 64.
path through the circuit to permit emitter to base current
The door opening device of the present invention incor
?ow in the power transistor 44. This path comprises lead
porates only two transistors and one relay, It is estimated
55
72 from the base 68, resistors 74, 76, lead 78, from which
that this circuit eliminates the necessity for four relays
extends lead 132 to switch 24. Lead 132 extends from
as presently used in conventional devices. The cost of
the other side of the switch 24 to ‘he relay contacts 66.
a transistor is approximately one-third that of the relays
In view of the fact that relay coil ‘52 is at this time ener
used. From this, it is evident that there is a, considerable
gized, contacts v66 will be closed. Lead 134 extends from
cost saving in the present ‘structure. Additionally, there
60
the relay contacts to parallel arranged resistor 136 and
is a considerable reductionin size and it has been found
light 1318. The resistor and light form a part of the afore
in practice that the present device has 'a service life of
mentioned test circuit. Lead 60 extends from the resistor
approximately 5 million cycles as compared to 50,000
‘136 and light 1318 to the secondary coil 36 to complete
100,,000 in previous devices, Another advantageous fea
the path for emitter to base current flow of the transistor
ture in the device resides in the use of a low-voltage cone ‘ ‘
44. This path will remain closed as long as the switch 24 65 trol transistor w ‘ch permits the use of low-voltage
is closed. Thus, untilthe person steps off the safety mat,
switches at the mats. Such low-voltage switches eliminate
the possibility of a dangerous shock‘to people‘ walking
the door will remain open.
The switch 24 also acts to prevent opening of the door
on the, mats.
The. one relay utilized in the present‘ device is 'a.‘ high
if a person is standing on the safety mat 18 when a second
70
quality,
relatively expensive relay which will perform
person steps onto the approach mat 16'. In this case,
switch 24 will be closed before switch 22 is closed. When
in the range of
. _
inclusion of such an expensive relay within
the price
switch 24 is closed without the previous energization of
structure
of
such
opening
devices
is
made
possible by‘
relay coil 52, a circuit is not completed from the transis
tor base ‘68 to power because the contacts 66 of the relay 75 the cost savings-effectuated elsewhere in the system. '_
will be in their normally open position. Thus, the door
3,039,038
Having thus described my invention, I claim:
1. An automatic door-opening transistor circuit comprising ?rst and second transistors each having a base
electrode, an emitter electrode, and a collector electrode,
tween the base of said ?rst transistor and said ?rst switch
to the base of the second transistor, said biasing resistor
being operative to prevent conduction by said second
transistor when said second switch is closed a relay 0011
the case of the ?rst transistor being connected to the 5 connected between said ?rst transistor collector and said
emitter of said second transistor, a normally open switch
source of power, said 0011 being energized when the ?rst
interposed between said ?rst transistor base and said sec-I
transistor conducts, a set of normally open relay con
ond transistor emitter, a source of power to excite said
?rst and second transistois to conduct when said switch
tiacts operated to close upon energization of said coil
and a circuit including a source of power and a door
is closed, a relay coil connected between said ?rst transis- 10 opening motor, said relay contacts being interposed in
tor collector and said source of power, said coil being
said lastmentioned circuit and being operative upon
energized when the ?rst transistor conducts, a set of nor-
closure to cause actuation of said motor.
nially open relay contacts operated to close upon energiza-
5. An automatic door-opening transistor circuit com
tion of said coil and a circuit including a source of power
prising ?rst and second transistors each having a base
and a door-opemng motor, said relay contacts being in- 15 electrode, an emitter electrode, and a collector electrode
ter-posed in said lastmentioned circuit and being operative
the base of the ?rst transistor being connected to the
upon closure to cause actuation of said motor.
emitter of said second transistor, a ?rst normally open
An automatic door-opening transistor circuit corn-
switch interposed between said ?rst transistor base and
prising ?rst and second transistors each having a base
said second transistor emitter, a source of power to excite
electrode, an emitter electrode, and a collector electrode, 20 said ?rst and second transistors to conduct when said
the base 0f the ?rst transistor being connected to the emitswitch is closed, a capacitor connected between the base
ter of said second transistor, a normally ‘open switch inand collector of the ?rst transistor, said capacitor being
terposed between said ?rst transistor base and said second
operative to cause conduction of the ?rst transistor for a
and second transistors to conduct when said switch is 25 coil connected between said ?rst transistor collector and
closed, a capacitor connected between the base and 001said source of power, said coil being energized when the
lector of the ?rst transistor, said capacitor being operative
?rst transistor conducts, ?rst and second sets of normally
to cause conduction of the ?rst transistor for a period of
open relay contacts opei ated to close upon energization
time after opening of said switch, a relay coil connected
of said coil a ?rst lead extending from a point between
between said ?rst transistor collector and said source of 30 the base of the ?rst transistor and said ?rst switch to
to close upon energization of said 0011, and a circuit ineluding a source of power and a door-opening motor, said
in the ?rst lead between the second set of relay contacts
land the base of the ?rst transistor, a ‘second lead extend
relay contacts being interposed in said lastmentioned cir- 35 i'ng from the ?rst lead from a point between said second
cuit and being operative upon closure to cause actuation
of said motor.
.33. An automatic door-opening transistor circuit com-
switch and the second set of relay contacts into connection
with the base of the second transistor, a biasing resistor
interposed in said second lead closure of said second
electrode, an emitter electrode, and a collector electrode, 40 operative to continue conduction of said ?rst transistor,
the base of the ?rst transistor being connected to the emitclosure of said second switch prior to energization of
ter of said second transistor, a ?rst normally open switch
the relay coil being operative, via said biasing resistor
interposed between said ?rst transistor base and said secto prevent conduction of said second transistor, whereby
?rst and second transistors to conduct when said ?rst 45 is closed prior to closure of said second switch, and a
switch is closed, a relay coil connected between said ?rst
circuit including a source of power ‘and ‘a door-opening
‘and second sets of normally open relay contacts operated
to cause actuation of said motor,
to close upon energization of said coil, the base of the ?rst 50
6. A device as claimed in claim 5 and further charac
Of the relay C0i1_being operative to Continue Conduction 55 ?rst transistor to conduct to energize said relay coil.
motoT60 erated signalling device in series with said second nor
prising ?rst and second transistors each having a base
emitter of said second transistor, Ia ?rst normally open 65
a biasing resistor connected in series from a point be- 70
No references cited.
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