Electromagnetic garage door locking apparatus

A locking apparatus for an electrically actuated garage door opener assembly is disclosed for preventing the unauthorized entry into a home or building. The locking apparatus comprises an electric solenoid and associated plunger and is electrically connected to the electrically actuated garage door opener in order to selective lock and unlock the garage door. In the deactivated condition of the opener, the plunger provides a locking mechanism. When the opener is activated, the solenoid is energized and the plunger is withdrawn from its locking position, thus permitting the door to open. An important feature of the present invention is a sensing mechanism which senses the locked and unlocked position of the solenoid plunger. If the plunger is in the locked position, the sensor will prevent actuation of the opener, thereby avoiding damage to the door or opener.

BACKGROUND OF THE INVENTION 
The present invention relates to an electrically actuated door opener 
assembly, and more particularly, to a positive locking mechanism for 
overhead garage doors that automatically engages to provide greater 
security against unauthorized entry through the door in the closed 
position. 
The overhead garage door assembly of the type in wide use typically 
includes a solid door pivotally mounted in a door frame so that, from the 
closed position, the door can move pivotally upwardly and rearwardly to an 
overhead, approximately horizontal position. The assembly also typically 
includes a remotely controlled mechanism to automatically open and close 
the door upon command. These automatic garage door openers are of at least 
four basic types:(1) the frictional engagement form; (2) the rack and 
pinion form; (3) the chain drive form; and (4) the plastic track drive. 
With the frictional engagement form, resilient rollers of the opener 
frictionally engage a member connected to and extending from the garage 
door. The force to open and close the garage door is applied by the opener 
motor to the rollers whose frictional engagement with the extended member 
causes the door to open and close. 
In the rack and pinion type, a rotatable pinion is connected through a 
guide track to a receiving bracket, which, in turn, is connected to the 
garage door so that the door may be opened and closed by rotational 
movement of the pinion. 
The chain drive type of automatic garage door opener is exemplified by a 
commercially available garage door opener manufactured by Genie Home 
Products, Inc., including models SP-229, SP-129, SP-99 and CH-130. A chain 
loop is connected to a sprocket on the opener motor at one end of a track, 
and at the other end of the track the chain is connected to a freely 
moving sprocket. The chain is also directly connected to the garage door 
by, for example, an L-shaped bracket so that as the opener motor rotates, 
the chain rotates with it, moving the L-shaped bracket and thereby moving 
the door. As an additional feature, the opener motor may rotate in either 
direction so that the door may be either open or closed upon command. 
All types of automatic garage door openers may be subject to unauthorized 
entry. For example, the frictional type may be forced open by application 
of sufficient force to the lower portion of the door to overcome the 
normal frictional bond between the resilient rollers and the extending 
member, which can create an access opening under the garage door. Using 
the rack and pinion type as another example, a sufficient force applied to 
the bottom of the door may cause the receiving bracket to back up along 
the pinion and thereby also create an access opening under the door. 
Similarly, the chain drive type of garage door opener is subject to 
unauthorized entry. For example, the chain may have sufficient "free play" 
to enable an intruder to slip under a garage door, or the intruder may be 
able to apply sufficient force to rotate the chain enough to create an 
access opening under the door. 
Regardless of the type of overhead garage door opener, the garage door 
inherently has some amount of flexibility. The intruder, using this 
flexibility to his beneift, and possibly in combination with one of the 
above-described deficiencies of the automatic openers, may be able to pry 
open a corner and slip through the access opening created thereby. 
The overhead garage door assembly and its susceptibility to unauthorized 
entry is discussed at length and in greater detail in the U.S. Pat. No. 
4,254,582 issued to Michael H. McGee. The apparatus described in the McGee 
patent includes a positive locking mechanism that prevents a person 
attempting unauthorized entry from forcing reverse movement of the opener. 
This locking mechanism includes two solenoids secured to the interior of 
the door frame, two latch members (one for each solenoid) secured on the 
interior of the garage door. The latch members receive a solenoid plunger 
when the door is in the closed position and the solenoid is not 
electrically actuated. Preferably, the solenoid is actuated by a signal 
from the conventional controls for the garage door opener so that when the 
opener is electrically actuated, it causes simultaneous actuation of the 
solenoids to withdraw their plungers from the latch members and release 
the door for movement from, or movement back, into its closed position. 
However, the McGee apparatus utilizes a separate power supply which 
operates independently from the power supply of the garage door opener. 
A significant problem with the apparatus described in the McGee patent 
arises when at least one of the solenoid plungers remains received within 
its latch member after actuation of opener motor. This condition, wherein 
the garage door is prevented from movement, may have been caused by one of 
many reasons, including a failure of the solenoid, a loose electrical 
connection, or even a mechanical jamming of the plunger within the latch 
member. In such an instance, the actuated opener motor may continue 
attempting to open the garage door while the solenoid and latch 
simultaneously restrain the door in the closed position. This unfavorable 
situation may result in damage to any of the various components of the 
garage door assembly, including the expensive possibility of burning the 
motor windings beyond repair. Alternatively, this situation may result in 
other types of damage, including the possibility that the solenoid 
assembly and the associated electrical wires could be torn or pulled from 
their affixed positions, causing damage to the door and door frame as well 
as the potential of personal injury from inadvertent contact with a loose 
or dangling electrical connection, or, at the instant of breakage, from 
being hit by flying objects such as broken pieces of the splintered door 
and associated apparatus. 
BRIEF SUMMARY OF THE INVENTION 
The present invention provides an apparatus for electromagnetically locking 
a garage door in the closed position for the purpose of substantially 
preventing attempts at unauthorized entry through the garage door. The 
present invention detects the locked and unlocked positions of the 
solenoid plunger so that the opener motor cannot operate while the door is 
locked, thereby precluding the possibility of damage that could be caused 
if the opener attempted to open the door in the locked configuration. To 
assure proper operation of the opener, the motor becomes operational only 
when the invention detects that the door has been electromagnetically 
unlocked. 
In a preferred embodiment of the present invention, the electromagnetic 
lock includes two solenoid assemblies, one affixed at each end of the 
upper door frame of an overhead garage door assembly. Two latch members 
are secured to the garage door proximate to each respective solenoid 
assembly so that the solenoid plunger of each assembly may be received 
therein and thereby lock the door in the closed position. Preferably, the 
solenoids are actuated by the opener assembly, so that when the control 
button is pushed by the operator, electrical power is immediately supplied 
to the solenoid, thereby causing a withdrawal of the solenoid plunger 
toward the unlocked position. When the plunger has been withdrawn to the 
unlocked position, a switch is actuated by the plunger which, in turn, 
electrically actuates the opener motor. The circuit including the opener 
motor, prior to such unlocking, is an open circuit. Thus, the opener motor 
becomes operational only when the solenoid plunger is, in fact, in the 
unlocked position. 
Furthermore, in a preferred embodiment, each latch member is affixed to the 
opposite top edges of the garage door. The solenoid assemblies are 
accordingly affixed to the upper corner of the door frame so that there is 
a very close clearance between the garage door and the door frame, 
substantially precluding attempts at unauthorized direct manipulation of 
the solenoid plungers by would-be intruders. 
These and other advantages and features of the present invention will 
become more fully apparent from the following description and appended 
claims taken in conjunction with the accompanying drawings.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT 
The present invention relates to an electrically actuated overhead garage 
door opener assembly and, more specifically, to an improved solenoid 
mechanism, safely and easily operable, for providing more secure 
retainment and locking of the garage door in its closed position. The 
present invention is illustrated in the following description integrated 
with a particular common form of overhead garage door opener installed for 
opening and closing a particular common form of garage door, the door 
being a solid or single-piece assembly. However, it should be understood 
that the principles of the present invention are equally applicable to 
virtually any form of overhead garage door and any form of overhead garage 
door opener assembly, and therefore, it is not intended to limit the 
principles of the present invention to the specific embodiment shown and 
such principles should be broadly construed. 
Referring now to FIG. 1, an overhead garage door is generally indicated at 
10, the door being of the solid type. The door 10 is mounted on the front 
wall 12 of a typical garage, within the opening defined generally by door 
frame 14. The door 10 may be mounted on the frame 14 in any known manner, 
advantageously by mounting each side of the door 10 to the standard 
pivoting side lever assemblies indicated generally at 16 and 18, which are 
mounted on opposite sides of the garage door frame 14, and includes 
counterbalancing springs 20, 22. As a result, garage door 10 may be moved 
from the generally vertical closed position shown in FIG. 1, pivotally 
upwardly to an overhead, nearly horizontal position (not shown), thereby 
permitting free passage through the door frame into the garage. It should 
be noted that, in the closed position illustrated in FIG. 1, upper frame 
surface 24 proximate to its lower edge makes contact with an upper edge 26 
of door 10. 
A selectively electrically actuable garage door opener assembly is 
generally indicated at 30. Such assemblies are in wide use and are 
available from many manufacturers, and the present invention can be used 
with any of these as well as the particular assembly described herein. The 
assembly 30 described herein is similar to that available commercially 
from Genie Home Products, Inc., such as models SP-129, SP-229, SP-99, and 
CH-130. The assembly 30 includes a guide track 32 mounted on upper frame 
surface 14, having a chain (not shown) rotatable about its length, an 
opener arm 34 slideably connected with guide track 32 and also affixed to 
the chain. The opener assembly 30 also includes a motor assembly box 40 
having a built-in control unit (not shown) affixed to the end of guide 
track 32 opposite door frame surface 14 and also structurally connected to 
the garage door ceiling (not shown) by members 41, 42. An opener motor 43 
(shown in FIG. 5) within motor assembly box 40 engages the chain, and 
furthermore is responsive to the built-in control unit. As a result, an 
acutation of the opener motor 43 moves the chain, which rotates about the 
guide track 32, thereby moving the opener arm 34 and finally moving the 
garage door 10. The opener motor 43 is actuable in either direction of 
rotation, so that the door 10 may be alternately opened or closed. 
The built-in control unit is operably connected to the opener motor, and is 
also connected to a button switch (not shown), which is provided with any 
of the above-described products of Genie Home Products, Inc. Pressing the 
button switch selectively actuates opening or closing of the garage door. 
However, the opener motor may be actuated in any known manner, for 
example, by a remote control sensing device (not shown) available with the 
above-specified product of Genie Home Products, Inc. The motor assembly 
box 40 is electrically connected to a suitable electric power supply (not 
shown) such as 110 v.a.c. household circuit, to supply the necessary 
electrical power to operate the various circuits, including the opener 
motor. 
Thus, as with the typical garage door assembly, with the garage door 10 in 
the closed position as shown in FIG. 1, the opener motor may be actuated 
to move the opener arm 34 rearwardly along guide track 32, carrying the 
garage door upwardly and rearwardly in pivotal motion to the overhead open 
position where the opener automatically stops. A subsequent actuation may 
reversely actuate the opener motor, so that the opener arm 34 moves 
forwardly, pivotally moving the garage door towards the closed position. 
In view of the prevalency of crime, and particularly burglaries in modern 
times, one of the principal problems encountered by owners of conventional 
garage door assemblies such as that described above, has been unauthorized 
attempts to open the garage door without electrical actuation. 
Unfortunately, many such attempts have been successful, as previously 
discussed in greater detail in the Background of the Invention. 
Therefore, in order to more securely retain the garage door 10 in its 
closed position, the present invention provides electrically actuated 
solenoid assemblies 50, 52 mounted on each opposite upper corner of the 
upper frame surface 24. In FIG. 1, the solenoid assembly 50 is shown 
affixed on the upper left hand corner of door frame 14, and solenoid 
assembly 52 is affixed to the upper right hand corner of door frame 14. 
For each solenoid assembly 50, 52, there is a corresponding L-shaped latch 
member 60, 62 affixed to upper edge 26 to engage with the respective 
solenoid assembly 50, 52 in the "locked" position shown in FIGS. 1 and 2. 
The various electrical connections between the solenoid assemblies 50, 52 
and the motor assembly box 40 are shown generally by line 54. Furthermore, 
latch members 60, 62 are so aligned that when the respective solenoid 
assembly plunger 110 is withdrawn into the assembly, each latch member 60, 
62 is not engaged, and therefore, the garage door 10 is free to move. 
Latch members 60, 62 may be affixed to door 10 in any well-known means, 
advantageously by securing screws 64, 66. 
Referring now to FIGS. 2, 3 and 4, each solenoid assembly 50, 52 is 
constructed substantially the same; thus, reference is made to only one 
such assembly 50. The assembly 50 includes a bracket 70 affixed to upper 
frame surface 24 in any well-known manner, advantageously by utilizing 
bracket mounting bolts 72 and 74. A solenoid housing 76 is affixed to 
bracket 70 in any well-known manner, advantageously utilizing mounting 
screws 77 to affix the housing 76 to bracket 70. Within solenoid housing 
76, a solenoid core 78 (shown in FIG. 4) is electrically connected to two 
leads, arbitrarily labeled solenoid AC hot lead 80 and solenoid AC neutral 
lead 82, the solenoid core 78 defining cylindrical cavity 79 (as shown in 
FIG. 4). On the upper portion of solenoid housing 76, a switch assembly 
generally shown at 84 comprising a metallic member 86 is affixed to 
housing 76 in any well-known manner, advantageously by welding metallic 
member 86 to a portion of solenoid housing 76. Switch assembly 84 also 
includes a first flexible contact arm 90 having a first electrical contact 
92, a pin seat 94 affixed thereon and further includes a second contact 
arm 96 having a second electrical contact 98 affixed thereon proximate to 
first contact 92. The bottom surface of the pin seat 94 resides adjacent 
to a pin 100 (shown in FIG. 4), the pin 100 being slideably mounted within 
housing 76 and projecting through the housing 76 and into cylindrical 
cavity 79 defined by solenoid core 78. 
As illustrated in FIG. 4, the switch assembly 84 is in its deactuated 
position since contacts 92 and 98 are not touching one another. Thus, as 
explained in more detail below in connection with FIG. 5, the opener motor 
43 is disabled in this position and, therefore, cannot incur any damage 
due to premature actuation while the locking mechanism is engaged. The 
motor 43 can be actuated only when the contacts 92 and 98 are engaged, and 
this can occur only when pin 100 has been forced upward by the movement of 
the plunger 110 in the solenoid core 78. 
The above-described solenoid housing 76, together with switch assembly 84 
is commercially available, and is substantially similar to box frame 
solenoid number 11S available from Guardian Electric Manufacturing 
Company, Chicago, Ill. 
Referring now to FIGS. 3 and 4, the solenoid assembly 50 also includes a 
cylindrical solenoid plunger 110 comprised of a metallic material 
responsive to a magnetic field. The cylindrical shape is adapted to slide 
freely within solenoid cavity 79 so that when electrical power is applied 
to solenoid core 78, the plunger 110 may move responsively. The plunger 
110 has a core end 112, which may move within core cavity 79, and has a 
locking or engagement end 114 at the opposite end, which engages latch 60 
in the closed or locked position demonstrated in FIG. 4. The core end 112 
preferably is provided with a non-magnetic tip so that the plunger 110 
will not inadvertently be attracted to metallic objects at the upper end 
of the core cavity 79, and will return to the locked position shown in 
FIG. 4. The exploded view in FIG. 3 illustrates the plunger 110 and its 
relation with the surrounding structures. The plunger 110 is insertable 
through, and slideable with, holes defined in the bracket 70, these holes 
being upper plunger guide 116 and lower plunger guide 118. In other 
embodiments (not shown), nylon bushings may be inserted annularly within 
the upper and lower guides 116, 118 in order to facilitate smooth movement 
of the plunger within the plunger guides 116, 118. 
With the plunger 110 inserted as in FIG. 4, a spring 120 is mounted 
surrounding the plunger 110, with one end of the spring adjacent to upper 
plunger guide 116 and the other end of the spring adjacent to snap clip 
122, which is snapped onto plunger 110 over annular groove 124 formed on 
plunger 110. As a result, the plunger 110 is biased by the spring 
downward, away from the core and toward the locked position shown in FIG. 
4. Further downward movement of plunger 110 is prevented by contact 
between snap clip 122 and lower plunger guide 118. Therefore, the solenoid 
assembly 50 remains in the locked state until electrical power is applied 
to the solenoid core 78. When such electrical is applied, the plunger 
engagement end 114 is withdrawn from its engagement with latch member 60, 
thereby freeing the door 10 to rotate to the open position. 
As the plunger 110, responsive to the actuation of the core, is so 
withdrawn into the core cavity 79, the core end 112 of the plunger 110 
contacts pin 100, pushing it and pin seat 94 upward, flexing the first 
flexible arm 90 so that first electrical contact 92 makes an electrical 
connection with second electrical contact 98. Only when the switch 
assembly 84 is in this actuated position will the opener motor 43 be 
energized and able to open the garage door. The distance separating the 
core end 112 of the plunger 110 and the pin 100 is calibrated to ensure 
that the locking end 114 is clear of the latch 60 before actuation of 
switch 84 occurs. Thus, the damage to the locking mechanism is avoided. 
After deactuation of the opener motor 43 and switch 84, the plunger 110 
returns to the locked position (although the latch 60 may not be present 
if the door 10 is open), thus permitting the pin 100 to return to the 
position shown in FIG. 4. This is accomplished because of the spring-like 
action of the flexible arm 90. 
In the preferred embodiment, each solenoid assembly 50, 52 is operably 
connected to the electric power supply through the garage opener assembly 
30 and electrical line 54 as shown in FIG. 1. At least two types of 
electrical connections are included in line 54: (1) connections to supply 
power to the solenoid core 78, and (2) connections to disable operation of 
the opener motor while the solenoid plungers 110 are in the locked 
position shown in FIG. 2. 
Generally, in the preferred embodiment, the means to supply electrical 
power to the solenoid cores 78 comprises an electrical connection between 
each solenoid core 78, the opener assembly 30, and the electric power 
supply, so that after the garage door opener assembly 30 is actuated, as 
hereinbefore described, the core 78 of the solenoid assembly 50 will be 
actuated with electrical power with the result that the plunger 110 will 
move to its withdrawn position disengaged from and free of latch member 
60. 
However, in other embodiments (not shown) the electrical power supply and 
the solenoid cores 78 may be electrically connected directly through a 
common switch so that the solenoid assemblies 50, 52 receive electric 
power directly from the power supply, separate and apart from the garage 
door opener assembly 30, requiring separate electrical actuation of the 
solenoid assemblies 50, 52 and garage door assembly 30 in proper sequence. 
Generally, the preferred embodiment has a means to disable operation of the 
opener motor which includes an electrical connection between each solenoid 
switch 84 and the circuit supplying power to the opener motor, so that the 
opener motor is operable only when each solenoid assembly 50, 52 has been 
actuated, and the plunger 110 has been withdrawn and actuation of switch 
assembly 84 has resulted from pressing together the first and second 
electrical contacts 92, 98 as hereinbefore described. 
Referring now to FIG. 5, a circuit is illustrated showing the electrical 
connections between the electric power supply, the opener motor 43, and 
the solenoid assemblies 50, 52 in the preferred embodiment. For purposes 
of reference, the components of solenoid assembly 50 are distinguished 
from the components of solenoid assembly 52 by an "a" on the elements of 
assembly 50, and a "b" on those of assembly 52. For example, solenoid core 
78 is denoted 78a on assembly 50 and 78b on assembly 52. 
The means for actuation of the solenoid assemblies includes a relay 130, 
such as relay number 1390P-2C-120A available from Guardian Electric 
Manufacturing Company, Chicago, Ill. The actuation of relay 130 is caused 
by application of electrical power to line 132, which is the line 
supplying power to the opener motor 43. This particular line normally 
supplies electrical power to the opener motor 43, and is selectively 
actuable by the user. In the Genie models SP-99, SP-129 and SP-229, 
previously described, this line 132 is of the color "orange," and is also 
denoted as the "up" connection. In other preferred embodiments (not shown) 
the solenoid cores 78a, may instead be electrically connected to a light 
(not shown) provided with the opener assembly 30. This light is normally 
actuated by the user each time the door is actuated in either direction 
and usually therein a delay time of several minutes directs which the 
light is actuated but the door is closed. In this embodiment (not shown) 
the operator motor circuit does not supply the power to actuate the 
solenoid cores 78a,b. 
In the preferred embodiment of the present invention, application of 
electrical power to the line 132 causes actuation of the relay 130 which 
is symbolized by the closing of switch 134. When switch 134 is closed, 
electrical power is supplied to the solenoid cores 78a,b of each solenoid 
assembly 50, 52, therefore causing the plungers 110a,b to move in the 
direction indicated by the arrows. As the plungers 110a,b move in this 
direction, they make contact with first flexible arms 90a,b, pushing them 
upward so that electrical contact is made between the first and second 
electrical contacts 92a,b and 98a,b. 
The opener motor 43 is electrically connected to a second electrical 
contact, for example contact 98a, advantageously by connecting the "black" 
wire, or the sole connection of the opener motor to AC neutral, to the 
second contact 98 of solenoid assembly 50. The first contact 92 of this 
solenoid 50 is electrically connected to the second contact 98 of the 
solenoid 52. The first contact 92 of the solenoid 52 is connected to AC 
neutral of the electric power supply 44. Because the sole connection of 
the motor 43 to AC neutral of power supply 44 is through this circuit, the 
opener motor 43 becomes operable only when the switches 84a,b (or, in 
other words, the two pair of contacts 92 and 98) of each solenoid assembly 
50, 52 are closed. Other circuits (not shown) are known in the art, which 
may accomplish same or similar purposes, and therefore the present 
invention encompasses such circuits, as well as the described circuit. For 
example, the power supply connection to AC neutral may be reversed with 
the connection AC hot, with substantially no effect upon the operation of 
the circuit. 
In summary then, the application of electrical power to actuate the opener 
motor 43 causes relay 134 to close, in turn actuating solenoid assemblies 
50, 52. The plungers 110a,b move upward, closing the switches 84a,b which 
complete the connection of the opener motor to AC neutral of the electric 
power supply. In this manner, the garage door opener assembly 30 cannot 
operate until physically unlocked and, therefore protecting the opener 
assembly 30, the door frame 14, and the garage door 10 from the damage 
that could occur if the opener motor were actuated with either of the 
plungers 110a, or 110b in the closed position. 
In the preferred embodiment, the solenoid assemblies 50, 52 are affixed to 
each upper corner of the garage door frame 24, and the latch members 60, 
62 are affixed in alignment thereto on the upper edge 26 of garage door 
10. In this configuration, the plungers 110a,b are substantially not 
subject to unauthorized manipulation, due in part to the fact that there 
is substantially no clearance between the face of garage door 10, and the 
upper frame surface 24, in part to its height above the ground, and also 
because any force tending to pry apart the adjacent portions of the door 
10 and the upper frame surface 24 increases the frictional force between 
either of the plungers 110a,b and the respective latch member 60,62, 
thereby rendering it more difficult to manipulate the respective plunger. 
The invention may be embodied in other specific forms without departing 
from its spirit or essential characteristics. The described embodiments 
are to be considered in all respects only as illustrative and not 
restrictive. The scope of the invention is, therefore, indicated by the 
appended claims rather than by the foregoing description. All changes 
which come within the meaning and range of equivalency of the claims are 
to be embraced within their scope.