Automatic door locking assembly

A deadbolt assembly adapted for use with automatic door openers having a movable carriage power driven on a track mounted above the door. A lift arm connects the carriage to the door which swings the door up and down about a horizontal axis in response to movement of the carriage. A deadbolt shaft reciprocates within a sleeve which is secured to the lower inside portion of the door. The shaft locks the door when closed by engagement with a lock opening. A cable connects the shaft to the carriage so that the shaft is lifted out of the opening as the carriage moves to lift the door. A slotted bracket connection between the door and lift arm provides a lost motion action to delay door movement until the shaft is out of the opening. In an alternative embodiment, the lift arm includes a free end at the bracket connection. The door connection includes slots which allow the free end to extend beyond the bracket and engage a door header opening after the door is closed. This locks the door in a closed position without the necessity of the deadbolt shaft and cable.

BACKGROUND OF THE INVENTION 
1. Field of the Invention 
The present invention relates to automatic door opening systems. More 
particularly, it pertains to an overhead door locking assembly that 
operates as part of a door opening system. 
2. Description of the Prior Art 
For large overhead doors that roll-up or swing-out, the use of automatic 
openers have become common. Such openers typically utilize a track mounted 
above the door for supporting a power-driven carriage. An elongated link 
arm connects the door to the carriage whereby the door will move in 
response to carriage movement. 
Problems have been encountered in preventing unauthorized intrusion due to 
the inherent slack in the overall system. There is usually sufficient 
looseness in the various joints, the track/carriage/drive connections and 
the door construction itself, to permit wedging of the door bottom and 
unauthorized entry. Numerous mechanisms have been devised to overcome this 
problem. 
In U.S. Pat. Nos. 3,435,558 and 3,526,994, a cam-operated latching 
mechanism is provided between the carriage and track means. This serves to 
prevent unwanted carriage movement, but does not address loose arm 
connections and inherent door flexure. 
U.S. Pat. No. 2,589,479 avoids the above deficiencies with a sliding bolt 
lock. The bolt traverses the top edge of the door and engages a door frame 
keeper to stop unwanted raising of the door. While this is effective for 
roll-up panel doors, it requires a bell crank arm and associated parts 
making it cumbersome and costly. Further, it is actuated by a keyed 
outside handle which, can be accessed by an experienced intruder. 
Door locks that automatically operate in conjunction with carriage movement 
are shown in U.S. Pat. Nos. 3,708,917; 4,442,631 and 4,597,224. Each of 
the above devices are distinguishable by the type of delay or lost-motion 
mechanism that is used to disengage the locks prior to door movement. In 
U.S. Pat. No. 4,597,224, the door arm comprises two sliding parts 
surrounded by the coils of a spring retained between opposing collars. 
Relative movement between the parts allows the carriage to unlock rocker 
latches prior to door movement. 
In the aforementioned U.S. Pat. Nos. 3,708,917 and 4,442,631, a bell crank 
lever and rocker plate, respectively, are the mechanical means by which 
unlocking occurs before door movement. In each of the above cases, 
substantial changes to conventional systems are required. As such, 
retrofitting of existing door operating devices is not economically 
viable. Also, the patented mechanisms require carefully aligned pivot 
parts which further require properly tensioned spring means. Such 
assemblies inherently create upkeep and maintenance problems. Still 
further, they are costly to purchase and are not amenable for the average 
householder to install. 
SUMMARY OF THE INVENTION 
The invention overcomes the complications of prior art mechanisms by 
providing a door locking assembly that operates by gravity and by means 
already present for opening the door. A deadbolt shaft is drawn by gravity 
into a lock opening when the door is vertical. Before the door is raised 
by a lift arm and carriage means, a delay bracket allows the carriage to 
move the deadbolt shaft out of the opening. Thereafter, the carriage, door 
and shaft move together to an open position. 
Particularly for roll-up multi-panel doors, a modified lift arm is used in 
conjunction with the delay bracket. When the door is lowered to a vertical 
position, a locking portion of the lift arm is moved by the carriage into 
a header lock opening. When the carriage moves to raise the door, the 
delay bracket allows the locking portion to disengage from the opening 
before the door is moved.

DESCRIPTION OF THE PREFERRED EMBODIMENTS 
With reference now to the drawings, the invention will be discussed in 
relation to its incorporation with conventional automatic door opening 
systems. As used herein the systems function to raise heavy doors along 
opposing side tracks (as with multi-panel roll-up doors) or about side 
hinge mechanisms defining a horizontal axis (as with single panel hinged 
doors). In both cases, the door opening systems utilize a powered drive 
means 12 to operate a track (or transmission) means 13. 
A carriage 14 is mounted upon the track means and moves thereon in response 
to actuation of said drive means. A lift arm 15 connects the door to the 
carriage whereby reciprocation of the carriage will raise and lower the 
door. The lift arm is generally an elongated flat bar member which is 
curved at one end. It usually hangs edgewise below the track means. 
As best shown in FIGS. 1 and 2, the track means is a linear chain or screw 
mechanism. It is mounted at its front end to supporting structure 16 above 
the center line c,c of single panel door 17. It extends rearward about 
perpendicular to the horizontal axis of the door when in a closed position 
as shown. The back end engages drive means 12 which is secured to beam 18 
of the supporting structure. 
In FIGS. 1-13, the invention comprehends the use of a deadbolt lock 
assembly to secure the closed door 17 from jimmying or other unauthorized 
intrusion. Such assembly includes a guide means shown as vertical sleeve 
20. The sleeve has mounting flanges 21 for securement by sleeve fasteners 
27 to the lower inside portion of door frame member 22. The lower sleeve 
end 23 is proximate the bottom end 24 of the door. 
Directly below the sleeve end is a keeper means. This may comprise a lock 
opening 25 in floor 26 as shown in FIG. 7. Alternatively, it may be a 
conventional pipe collar secured to the floor surface (not shown). 
Mounted for reciprocation within the sleeve is shaft 30. The shaft is a 
straight structural element having a length greater than the sleeve. It is 
desirable that the shaft and sleeve have similar cross-sectional shapes to 
facilitate shaft movement. The shaft includes a locking tip end 31 that 
engages the keeper means when door 17 is in the closed position. The tip 
end, at least, should be resistant to shear forces and be sufficiently 
heavy to overcome any counteracting friction forces upon its downward 
gravity movement within the sleeve. 
Actuation means, shown as cable 34, is connected to the shaft lift end 32. 
The connection comprises a cable loop 35 through shaft aperture 33. Other 
actuation means, such as rope, wire, chain, belt or combinations thereof 
may be used. Preferably, such means should be flexible, but linearly 
unyielding. 
From its connection with the shaft, the cable is threaded through eyelet 
means 37 on frame member 22 to carriage 14. The carriage connection most 
simply can comprise another cable loop 38 through or about any one of; a 
carriage aperture, clevis part or carriage cross-bolt. It is important 
that the cable and cable connections be tight so that carriage movement 
will result in a substantially immediate like movement of the shaft. 
As the carriage moves, so will the door via lift arm 15. However, upon the 
start of lifting, the invention contemplates use of an improved door 
movement delay means so that the gravity deadbolt assembly can first 
become disengaged. The delay means is part of a unique bracket means 
interconnecting the upper portion of door 17 to lift arm 15. 
The bracket means for all embodiments of the invention includes a base 
plate 40 attached by plate fasteners 41 to the upper portion of an 
overhead door. As shown in FIGS. 1-13, the plate is attached to top end 42 
of door 17. At least one, and preferably two, pivot plates 43,44 extend 
upwardly from the base plate. They are aligned with the door centerline 
and are parallel to the side of delay end 45 of the lift arm. The plates 
are spaced-apart a distance greater than the thickness of the delay end to 
form a slide channel 46. This arrangement allows for relative movement 
between the plates and the delay end. 
The bracket delay means shown in FIGS. 1-10, 14, 15 and 19 comprises an 
elongated slot 48 through the pivot plate(s). It extends a predetermined 
distance across a major portion of the plate upper width and is generally 
horizontal when the door is down. A hinge pin 50 is secured to the delay 
end and extends transversly therefrom through the slots. Preferably, the 
pin is a hardened headbolt fastened with a conventional washer and nut 
combination 51. It hinges delay end 45 to the door and permits limited 
reciprocation defined by the slot length within slide channel 46. 
As best shown in FIGS. 2 and 5, the hinge pin will abut forward end 54 of 
the slot to secure the door in a down position. Upon activation of drive 
means 12, the track means will draw the carriage rearward. This action 
will pull cable 34 through eyelet means 37 and cause shaft 30 to be lifted 
out of lock opening 25. 
Upon clearance of tip end 31 from the opening, hinge pin 50 will have slid 
across slot 48 into abutment with slot back end 55. At this point, 
carriage movement force will be transferred to the bracket means and the 
door will begin its upward swinging movement until it is fully open as 
seen in FIG. 3. 
To insure that the tip end has cleared lock opening 25 prior to door 
movement, slot 48 must have a length greater than the tip engagement 
distance D. Further, the shaft guide means should retain control of the 
shaft at maximum shaft elevation when the door is fully open. In normal 
installations, this distance does not exceed one third the height of the 
door. 
To facilitate smooth operation of the door movement and locking mechanisms, 
the bracket means may include an optional spring biasing means. As shown 
in FIGS. 9 and 10, this comprises a tension spring 56 that connects base 
flange 57 with extension 58 of hinge pin 50. The spring biases pin 50 
toward back end 55 of the elongated slot and provides smoother downward 
movement of the door. 
With reference to FIGS. 11-13, 16 and 17, an alternative delay means is 
illustrated. The delay end 45 is provided with an elongated slot 49. The 
slot preferably extends along the median axis of the delay end. Hinge pin 
52 extends through the slot and is secured to the unslotted opposing pivot 
plates 43',44'. 
The delay movements are the same as before with the delay end reciprocating 
in slide channel 46. In this sequence, however, pin 52 will abut slot back 
end 55' during down movement of the door. During door raising, the slot 49 
will move along pin 52 until the pin abuts slot forward end 54'. Force 
transfer then takes place and the door will begin to rise. 
Although the embodiments of FIGS. 14-19 may be used with all types of 
overhead doors, they have particular utility for the aforementioned 
multi-panel doors that roll on opposing side tracks. In these embodiments, 
the deadbolt shaft and cable may be omitted. The bracket and delay means 
are the same as in FIGS. 1-13. Only the lift arm and keeper means are 
changed. 
As best illustrated in FIGS. 14 and 15, lift arm 60 comprises a first 
section 61 that hangs edgewise from a pivot connection 62 on carriage 14. 
The section is preferably straight and may comprise overlapping parts for 
longitudinal adjustment. The parts are secured with part fasteners 63 
extending through adjustment openings 64. 
The first section merges at an obtuse angle "a" into locking portion 64. 
Preferably, the locking portion is straight and angle "a" is greater than 
about 100.degree.. The locking portion includes a slide segment 66. This 
segment reciprocates within the slide channel of the bracket means 
previously described. Note that the bracket means is secured to the top 
end 73 of door panel 72 in centered alignment beneath the aforementioned 
carriage and track means. 
The locking portion terminates outward from the slide segment at free end 
67. When the door is in a down position, the free end is defined as that 
part of the locking portion that extends past the exterior surface plane 
of door panel 72 into an arm retention means. 
As shown, the arm retention means comprises an engagement opening 69 which 
is sized to receive free end 67. The opening is formed into header 68 
directly adjacent the bracket means. It may include a face plate 70 that 
outlines the opening. The plate is secured to the header with plate 
fasteners 71. 
It will be understood that when the door is in a closed position, as shown 
in FIG. 14, the delay slots 48 should be horizontal. The locking portion 
should also be horizontal. Otherwise, difficulty may be incurred in free 
end movement into and out of the engagement opening. 
Further, note that FIGS. 16 and 17 show the same modified delay means as 
that illustrated in FIGS. 11-13. Also, note that the length of the delay 
slots 48,49 should exceed the length of free end 67. Only in this way will 
the free end clear the retention means before the door commences upward 
movement as shown in FIG. 15. 
In operation, the lift arm/delay means sequence is the same as with the 
FIGS. 1-13 embodiments. Upon rearward movement of carriage 14, the lift 
arm will move backward and free end 67 will withdraw from the engagement 
opening. Upon abutment of the hinge pin against the slot back end, the 
door will then begin rising along defined side tracks. When closing, the 
reverse action will occur with the hinge pin remaining in the slot back 
end until the door touches down. Continued forward movement of the 
carriage will then move the locking portion and free end forward until the 
hinge pin abuts against the slot forward end. At this point, the free end 
will be within the engagement opening and the door will be securely 
locked. 
With the above uniquely defined locking portion and delay means, the lift 
arm is able to function as (1) a force transmission link, (2) a delay 
part, and (3) a locking part. Such triple function avoids the troublesome 
prior art mechanisms. It greatly simplifies the overall operation and is a 
significant advancement in the art. 
While the invention has been described with respect to preferred 
embodiments, it will be apparent to those skilled in the art that other 
modifications may be made without departing from the scope and spirit of 
the invention. Accordingly, it is to be understood that the invention is 
not to be limited by the embodiments specifically described, but only by 
the scope of the appended claims.