Method and apparatus for operating motorized gate upon loss of electrical power thereto

A backup gate controller for a motorized gate detects the loss of power to the gate and causes the gate motor to open the gate in response to loss of power or by an external trigger thereafter. The backup gate controller may be inserted between an existing gate controller and gate motor to bypass the existing controller when power loss is detected. Alternatively, the backup gate controller may be directly connected to the existing gate controller to cause the existing controller to open the gate when power loss is detected. A combined gate controller/backup controller may also be provided. Upon opening the gate, the backup controller and/or the gate controller may prevent the gate from being closed. The backup controller is battery powered and preferably includes a battery charger.

FIELD OF THE INVENTION 
This invention relates to motorized gates, doors or other motorized access 
restricting devices, and more particularly to a method and apparatus for 
operating such a motorized gate, door or access restricting device upon 
loss of electrical power thereto. 
BACKGROUND OF THE INVENTION 
Motorized gates and doors are well known access restricting or security 
devices for parking lots, buildings and other restricted areas. All such 
devices will hereinafter be referenced to as "motorized gates". Typically, 
motorized gates include a motor for opening and closing the gate and an 
electronic gate controller for controlling operation of the gate motor. 
The electronic controller may be responsive to a sensor, key, switch, 
token or other access granting device for opening and closing the gate. A 
power supply, typically an alternating current (AC) power supply, provides 
electrical power to the electronic gate controller. 
A persistent problem for known motorized gates is the need to allow these 
gates to open upon loss of electrical power thereto. Such loss of 
electrical power may occur as a result of a lightning storm, fire, or 
other disaster, or as a result of commonly occurring power outages. In the 
event of a loss of power, the inability to open the gate may produce an 
inconvenience for those in the area who must wait until power is restored 
in order to leave or enter the area. More importantly, in an emergency or 
disaster situation, loss of power may trap people in the area preventing 
evacuation and preventing the entrance of emergency personnel. 
Accordingly, local ordinances often require motorized gates to provide for 
opening upon loss of electrical power. Many insurance companies also 
require the inclusion of a manual override to allow opening the motorized 
gate upon loss of electrical power. 
A simple solution for allowing a motorized gate to be opened upon loss of 
power is a manual release. The manual release may unlock the gate from the 
gate motor, so that the gate may be manually opened. However, such a 
manual release must be mounted inside the restricted area to prevent 
unauthorized persons from activating the manual release and thereby 
gaining access to the restricted area. Unfortunately, by placing the 
manual means inside the gate, activation by fire or other emergency 
personnel outside the restricted area is precluded. 
Another manual gate override is disclosed in U.S. Pat. No. 4,658,543 to 
Carr, which illustrates a controller which is connected between the main 
power supply and the gate motor. If there is a malfunction or a power 
outage, a manual bypass switch allows the user to bypass the controller 
and directly connect a standby battery to the motor to thereby operate the 
gate. Unfortunately, as stated above, such a manual bypass switch allows a 
bypass by unauthorized personnel. Moreover, a battery powered bypass which 
allows opening and closing the gate under backup battery power may allow 
the battery to discharge when the gate is in the closed position, thereby 
again preventing opening of the gate. A manual bypass also precludes 
automatic operation during an emergency situation. 
It is also known in the art to employ a backup door opening system which 
opens a non-motorized door in response to a power outage. For example, 
U.S. Pat. No. 4,129,811 to Pearson discloses an emergency door opening 
system which operates in connection with a ventilation system used in 
barns or other structures which house animals. The ventilating system 
normally provides air ventilation to the barn. When power to the 
ventilating system is lost, a relay system energizes a battery powered 
motor to open a door on the barn and provide emergency ventilation. The 
Pearson reference does not disclose or suggest a backup system which could 
be employed with a motorized gate, the motor of which opens and closes 
during normal use, to allow operation of the motorized gate upon loss of 
electrical power. 
The art has heretofore suggested other systems for operating a motorized 
gate in the event of power loss thereto. For example, U.S. Pat. No. 
4,490,624 to Luker discloses a door control apparatus for an automatic 
door which includes a main power supply which normally drives a main door 
motor to open and close the door. A second battery power supply is 
provided to operate a second door motor. A relay detects when there is a 
main power supply failure and thereby connects the battery to the second 
motor for driving the door via a common drive assembly. Unfortunately, the 
Luker reference requires the use of a second drive motor for emergency 
conditions. The need for a second motor adds greatly to the cost, and 
makes it difficult to adapt the system to existing motorized doors or 
gates. 
The art has also heretofore provided uninterruptable power supplies (UPS) 
for use in connection with computers or other critical systems. A UPS, for 
example as described in U.S. Pat. No. 4,675,538 to Epstein, typically 
substitutes a backup battery for the normal AC power service upon loss of 
normal AC power. However, such UPS's are not appropriate for use in 
motorized gates for at least two reasons. First, a UPS will continue to 
allow the motorized gate to open and close until its battery discharges. 
If the battery discharges when the gate is closed, emergency exit and 
entry is again prevented. Moreover, UPS's tend to be expensive because 
they are designed to provide uninterrupted power with a smooth switch over 
in addition to long term battery power for use during long power losses. 
While this expense may be justified for computer systems, the expense 
would preclude use of a UPS with a motorized gate. 
Backup power supplies have also been incorporated into other expensive 
equipment. For example, U.S. Pat. No. 4,791,443 to Foley et al. discloses 
a backup power supply for photographic processing equipment which allows 
any film in progress to be processed. There is no disclosure or suggestion 
of any backup power supply for a motorized gate. 
SUMMARY OF THE INVENTION 
It is therefore an object of the invention to provide an improved method 
and apparatus for operating a motorized gate upon the loss of electrical 
power thereto. 
It is another object of the invention to provide a method and apparatus for 
operating a motorized gate upon loss of electrical power which may be 
adapted to an existing motorized gate without requiring additional motors 
or other costly components. 
It is yet another object of the invention to provide a method and apparatus 
for operating a motorized gate upon loss of electrical power which does 
not require the use of costly uninterruptable power supplies. 
These and other objects and advantages of the present invention are 
provided by a backup gate operating apparatus which is adapted for use 
with a motorized gate, the motorized gate including a motor for opening 
and closing the gate and an electronic gate controller for controlling 
operation of the motor, with the electronic gate controller being powered 
from a gate power supply. The backup gate operating apparatus includes a 
detector which is adapted for electrical connection to the gate power 
supply for sensing the loss of power from the gate power supply. A battery 
powered backup gate controller is also provided for connection to the 
detector for controlling the gate motor to open the gate in response to 
the loss of power or to an external trigger thereafter. According to the 
present invention, the backup controller automatically takes control of 
the motorized gate when a power loss is detected and opens the gate and 
maintains the gate open until power is restored or the gate is manually 
closed. Preferably, the backup controller will only allow the gate to open 
once, and will then disable itself after the gate is opened. 
In one embodiment, the backup gate controller is directly connected to the 
gate motor to bypass the electronic gate controller and directly control 
the motor to open the gate in response to loss of power. In another 
embodiment, the controller is directly connected to the existing 
electronic gate controller to cause the existing electronic gate 
controller to control the gate motor to open the gate. It will also be 
understood by those having skill in the art that the backup gate operating 
apparatus of the present invention may be retrofitted onto existing 
motorized gates or may be designed as part of a newly manufactured gate. 
In either case, the backup gate controller may be integrated into the 
electronic gate controller. 
The backup gate operating apparatus and method of the present invention 
opens a motorized gate in response to a power loss, using the pre-existing 
gate motor. A second motor is not required. Moreover, the battery powered 
backup gate controller will only allow the gate to open once, to thereby 
ensure that the backup controller's battery does not fully discharge when 
the gate is closed. Costly uninterruptable power supplies are also not 
required. Low cost backup protection for motorized gates is thereby 
provided, to enhance safety and comply with local ordinances and insurance 
requirements. 
The backup gate operating apparatus and method of the present invention may 
immediately open the gate upon loss of power. Alternatively, upon loss of 
power, the gate may wait for a command from an external trigger, such as a 
manual emergency switch or other signal, to open the gate. This emergency 
switch or signal may be mounted in a standard lockbox or adjacent to the 
backup gate operating apparatus for easy access by emergency crews. An 
automatic delay may also be provided to ignore momentary power outages. 
The backup gate controller may be designed to operate in connection with a 
limit switch or position sensor which typically indicates that a gate is 
open, and a lock which locks the gate in the closed position. In 
particular, if the gate is closed, the lock may be activated to unlock the 
gate before it is opened. Once the open gate position sensor is detected, 
a braking force may be applied to the motor to stop the gate. The backup 
gate controller may also be coupled to an alarm which generates an alarm 
signal when the motor is activated. This alarm signal may be coupled to a 
light or other known alarm means. Finally, if the gate does not open when 
the motor is energized, a second alarm signal may be generated to indicate 
a stuck gate or other fault.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT 
While the present invention will be described hereinafter with particular 
reference to the accompanying drawings, it is to be understood at the 
outset of this description that persons skilled in the applicable arts 
will be able to modify the specific arrangements herein described and 
shown while continuing to achieve the desired result of this invention. 
Accordingly, the description and illustrations are to be taken as broad, 
teaching disclosures directed to persons skilled in the appropriate arts, 
and not as restricting the scope of the present invention. 
FIG. 1 illustrates a backup gate operating apparatus 10 adapted for use 
with a motorized gate 30. The motorized gate is controlled by an 
electronic gate controller 20. The gate 30 includes a gate motor 31 for 
opening and closing the gate, a position sensor 32 to indicate the 
position of the gate 30, and lock 33. The gate controller 20 typically 
controls gate 30 via a series of wired connections in a manner well known 
to those having skill in the art. Relay interface 50 which comprises a 
number of relays (shown schematically) may be connected between controller 
20 and gate 30. Preferably, relay interface 50 is a part of the backup 
gate operating apparatus 10 . This relay interface 50 allows the switching 
of control signals and power so that they can flow between the gate 30 and 
the electronic gate controller 20 or between the gate 30 and the backup 
gate operating apparatus 10. Electronic gate controller 20 is powered from 
a main power source 47. During normal operation, gate 30 is powered by 
main power supply 47 through electronic gate controller 20. 
The backup gate operating apparatus 10 includes an alternate gate power 
supply 41, such as a battery or batteries, and a power unit 42 for 
regulating the power supplied by batteries 41 and for converting the 
battery voltage and current levels to those levels necessary to operate 
the motor 31 and lock 33 of gate 30. A backup gate controller 43, which 
may be a microprocessor or logic unit, controls the operation of apparatus 
10, as described below. Control switches 44 allow setting of various 
options, as described below. A power loss detector 45 senses the loss of 
power at main supply 47. A battery charger 46 maintains batteries 41 fully 
charged. Gate power supply 47 is also connected to the power loss detector 
45 and battery charger 46. An external trigger 48 and a external alarm 
circuit 49 may also be provided, as described below. It will be understood 
by those having skill in the art that a single backup gate operating 
apparatus 10 may control more than one gate. For example, this could be 
accomplished by expansion ports and/or additional printed circuit boards. 
In the embodiment illustrated in FIG. 1, the backup gate operating 
apparatus 10 is connected between the gate 30 and the gate controller 20 
via interface 50. As described in detail below, upon loss of power, backup 
gate controller 43 controls interface 50 to disconnect electronic gate 
controller 20 and connect backup gate controller 43 and power unit 42 to 
the gate 30. It will be understood by those having skill in the art that 
interface 50 may replace an existing relay interface to allow the 
alternate control paths described above. 
The backup gate operating apparatus 10 allows the gate 30 to open upon loss 
of electrical power thereto. Such loss of electrical power may occur as a 
result of an electrical storm, fire, or other disaster, or as a result of 
commonly occurring power outages. The backup gate operating apparatus 10 
includes a well known power detector 45 which is adapted for electrical 
connection to the main power supply 47 for sensing loss of power from the 
main power supply 47. Battery powered backup gate controller 43 is 
connected to the detector 45 for controlling the gate motor 31 to open the 
gate 30 in response to the loss of power. 
According to the present invention, the backup controller 43 automatically 
takes control of the motorized gate 30 when the power loss is detected by 
causing the relays of interface 50 to switch, as illustrated schematically 
in FIG. 1. Backup controller 43 opens the gate 30 and maintains the gate 
30 open until power is restored or until the gate 30 is manually closed. 
The backup controller 43 will only allow the gate 30 to open once. 
Alternatively, the gate 30 can open a predetermined number of times, for 
example twice, during one continuous power outage, assuming there is 
sufficient capacity in the battery 41 for operation. However, in the 
preferred embodiment, to ensure that the backup controller's alternate 
gate power supply 41 (battery) is not fully discharged by cycling the gate 
30 open and closed (possibly leaving the gate 30 closed), the backup gate 
controller 43 will maintain the gate 30 in the open position once it is 
first reached in the power outage condition. 
The backup gate operating apparatus 10 and method of the present invention 
may immediately open the gate 30 upon loss of power from the gate power 
supply 47. Alternately, upon loss of power the backup gate operating 
apparatus 10 and method of the present invention may wait for a command on 
the external trigger or emergency switch 48 or other signal, to open the 
gate 30. Suitable external triggers include roadway loop detectors, radio 
receivers, strobe light receivers, telephonic controllers, or the like. A 
control switch 44 may indicate selection of automatic or external trigger 
operation. The external trigger 48 may be mounted in a standard lock box 
or adjacent to the backup gate operating apparatus 10 for easy access by 
emergency crews. Detector 45 or backup gate controller 43 may be 
configured to provide a predetermined delay (for example, ten seconds) 
before triggering, to ignore momentary power outages. 
The backup gate controller 43 may be designed to operate in connection with 
a position sensor 32 which typically indicates that the gate 30 is open, 
and a lock 33 which locks the gate 30 in a closed position. Both "normally 
open" and "normally closed" limit switches may be employed, with a control 
switch 44 indicating the type of switch employed. If the gate 30 is 
closed, the lock 33 may first be activated to unlock the gate 30. Once the 
position sensor 32 indicates that the gate has been opened, a braking 
power may be applied to the motor 31 to stop the gate 30. Braking power 
may be selected by via a control switch 44. 
The backup gate controller 43 may also be coupled to an external alarm 
circuit 49, which generates an alarm signal when the motor 31 is activated 
for opening the gate 30 When there is a power outage. This alarm signal 
may be coupled to a light or other known alarm means. If the gate 30 does 
not open when the motor 31 is energized, a second alarm signal may be 
generated to indicate that the gate 30 is stuck or that a malfunction has 
occurred. These alarm signals are conventionally activated by software 
programs or logic elements. 
The embodiment illustrated in FIG. 1 places the backup gate operating 
apparatus 10 between the existing electronic gate controller and gate 30 
Referring now to FIG. 2, a second embodiment of the present invention is 
shown in which the backup gate operating apparatus 10, and particularly 
the backup gate controller 43, is directly connected to the existing 
electronic gate controller 20 via connections 36 and 52 to direct 
operation to the existing electronic gate controller 20 when loss of main 
power is detected. Connection 36 provides for feedback between the 
electronic gate controller 20 and backup gate controller 43 so that gate 
status information may be transferred therebetween. A suitable alternative 
may have feedback connections between the gate 30, electronic gate 
Controller 20, and backup gate controller 43. 
In FIG. 2, main power supply 47 and batteries 41 are connected to power 
unit 42 which supplies power via connection 52 to the electronic gate 
controller 20 and then to the gate 30. Power sensor 55 is connected 
between the power unit 42 and electronic gate controller 20 for detecting 
the power being consumed by the electronic gate controller 20 and the gate 
30. If a predetermined amount of power is being consumed when under 
battery power, power sensor 55 respectively deenergizes the electronic 
gate controller 20 and gate 30. This power sensor 55 may be a part of the 
power unit 42 in another embodiment or it may not be needed at all. 
The embodiments of FIGS. 1 and 2 are particularly designed to allow the 
backup gate operating apparatus 10 of the present invention to be 
retrofitted onto an existing motorized gate or electronic gate controller. 
Especially, for newly manufactured gates, an electronic gate controller 
and a backup gate controller may be provided in a single integrated unit, 
such as a an electronic o microprocessor or logic unit. FIG. 3 illustrates 
such an integrated controller 60 which provides the functions of well 
known electronic gate controllers and the functions of the backup gate 
controller of the present invention. Here, as compared to FIGS. 1 and 2, 
main power supply 47 and battery 41 are connected to power unit 42 which 
is directly connected to the gate 30. There may be many other ways to 
supply power to the gate 30. 
Referring now to FIG. 4, a flow chart representation of the sequence of 
operations performed by the backup gate operating apparatus 10 will now be 
described. These operations may be performed by a backup gate controller 
43 which is connected between a gate controller 20 and a gate 30 (FIG. 1), 
or which is directly connected to an electronic gate controller 20 (FIG. 
2). These operations may also be performed by a backup gate controller 
which is a part of integrated controller 60 (FIG. 3). 
Referring again to FIG. 4, at block 71, the main power supply 47 is 
continuously monitored via detector 45. Once a power supply loss is 
detected for a predetermined time, such as 10 seconds, the state of 
control switches 44 are checked to see if automatic or external operation 
has been selected (block 72). If external operation was selected, the 
external trigger 48 is monitored, at block 73, until actuation of external 
trigger 48 is sensed. If power is restored before the external trigger 48 
is activated (block 74) processing returns to point "A". 
When the external trigger 48 is actuated (block 73), or for automatic 
operation, as soon as main power is lost (block 72), the relay, preferably 
in interface 50, Which controls position sensor 32 is activated (block 
75). The position sensor 32 polarity is then checked at block 76, so that 
an open gate may be correctly detected. A control switch 44 may be 
provided to check for a normally open (normal) or a normally closed 
(reversed) position sensor 32. If a reverse polarity has been indicated, 
the logic is reversed at block 77 to detect position sensor 32 in a closed 
position. A check is then made (block 78) to ensure that the gate 30 is 
actually closed. If the gate is not closed (i.e. open), then operation 
returns to point "A". If the gate 30 is closed, it is opened by activating 
the motor 31 and lock 33 (block 79). External alarm 49 may also be 
activated. 
Operation then waits to detect an open gate by detecting a change in the 
state of position sensor 32 (block 80). If the change in the position 
sensor 32 is not detected within forty-five seconds or some other 
predetermined time period (block 81), indicating the gate 30 is stuck, or 
another fault is present, the external alarm circuit 49 may be pulsed 
(block 82) until automatically or manually reset (or until battery 41 is 
depleted) to provide a second alarm which indicates a stuck gate. The 
pulsing alarm is deactivated at (block 83). 
If the change in the position sensor 32 is detected, indicating that the 
gate 30 has properly opened (block 80), the external alarm circuit 49 is 
also deactivated (block 83). The motor 31 and lock 33 are deactivated 
(block 84) after the alarm is deactivated (block 83). The backup gate 
controller 43 waits for the main power 47 to be restored (block 85) for 
providing an automatic reset. It is understood by one skilled in the art 
to provide for a means to externally trigger a reset. Once reset, the 
operation returns to point "A". 
In the drawings and specification, there have been set forth preferred 
embodiments of the invention, and although specific terms are employed, 
they are used in a generic and descriptive sense only and not for purposes 
of limitation, with the scope of the invention being set forth in the 
following claims.