Closure fasteners – Braces
Reexamination Certificate
2000-09-05
2002-10-29
Friedman, Carl D. (Department: 3635)
Closure fasteners
Braces
C292S339000, C292S25900A, C292S289000, C292S292000, C292S295000, C292S262000, C292S277000, C292S251500
Reexamination Certificate
active
06471264
ABSTRACT:
FIELD OF THE INVENTION
The present invention relates generally to door security devices which allow locking of the door in a fully closed position and a partially open position. The invention has specific application to the field of protection from home invasion and forced entry of any premises or building.
BACKGROUND OF THE INVENTION
Residential security is an unfortunate but necessary part of owning or renting a home. Security of a commercial premises is also essential. Most premises are equipped with standard type door locks, dead-bolts and latches, which are effective when the door is closed, but it is frequently desirable to allow the door to open partially to talk to visitors. Opening the door subjects the occupants to an increased threat of home invasion or forced entry. Typical devices, such as door chains, designed to permit partial opening of the door, are inherently weak. The mounting of the chain and its components to the door frame and the door itself may be broken or torn from the their attachments. As such, there is a need in the market for door security devices that permit partial opening of the door without compromising security.
Many prior art devices have been developed which purport to solve this problem. However, none of the devices have been commercially successful because each of them has innate disadvantages that make them unattractive, non-functional or merely ineffective. The following represents a short discussion of the prior art inventions and the weaknesses thereof.
U.S. Pat. No. 3,690,709 (hereinafter referred to as '709) is a cable based locking system. The cables attach to specialized hinges and are disposed so as to extend from each hinge angularly across the interior surface of the door to the bottom handle side corner. At the bottom handle side corner of the door, the cables are engaged via an offset flange to a rotating pivot bolt which is secured to the floor and/or the wall. The '709 invention lacks visual appeal. People who have an interest in the aesthetic appeal of their homes or commercial establishments are unlikely to purchase an invention such as this, which requires the permanent fixture of cables covering most of the door's interior surface. In addition, the cables are bulky and may reduce the functionality of the door as they take up a considerable amount of room. The device also puts a relatively large amount of torque and shear force on the pivot bolt. The offset flange, required by this invention to permit partial door opening, has the effect of laterally displacing the device's bracing elements (the pivot bolt and its housing) away from the edge of the door. However, any force exerted to open the door is still exerted at the door's edge and causes a torque on the pivot bolt which is proportional to the length of the offset flange and the force itself. Finally, the device requires the purchase specialty hinges, which add to the expense of the invention and to the complexity of installation.
U.S. Pat. No. 4,601,502 (hereinafter referred to as '502) is a recessed floor plug with a spring loaded lock bar, which, when engaged, extends upwards from the floor plug, so as to block the path of the door. When not engaged, the lock bar retracts into the floor so that it is not intrusive. The lock bar is engaged by exerting downward pressure on the top of the bar, which depresses the bar below the floor surface and activates a spring release mechanism. One disadvantage of the '502 invention is its arrangement in the floor. Because the invention has a relatively large number of moving parts, all housed in the recessive floor plug, dirt, dust and other contaminants (which accumulate naturally in doorways) can interfere with the device performance. The concentric arrangement of the lock bar within the floor plug is an entirely vertically oriented apparatus. Consequently, the device has little horizontal bracing, making it weaker when acting against horizontal forces tending to open the door. An additional consequence of the concentric arrangement is that the lock bar can only be as long as the depth of the floor plug. A large force acting against the upper part of the door can cause the door itself to break over the relatively short lock bar. Finally, the activation mechanism of the invention is difficult to operate. If the activation mechanism requires depression well below the floor, then a person may need to bend to floor level and use their hands; conversely, if the activation mechanism requires only minimal depression, then a person or household pet may accidentally activate the device by walking on it.
U.S. Pat. No. 5,040,835 (hereinafter referred to as '835) comprises an angularly disposed rod, one end of which fits into an angular floor plug. The other end of the rod is inserted into a door mounted keeper and is vertically slideable therein, such that when the door is opened slightly, the rod slides vertically in the keeper and the rod angle changes. The disadvantages of the '835 invention include the relatively large amount of space that the angularly disposed rod occupies in the entranceway of the premises. The floor plug of the device is also difficult to install, because it must be drilled at an angle and in precisely the correct location to permit the rod to translate properly within the keeper. In addition, the floor plug must be bored sufficiently wide to accommodate both different angular orientations of the rod. The extra room in the plug introduces play in the device and permits torque to act against the rod about the floor axis, such that an intruder may agitate the device, potentially bending or breaking it. Agitation, in turn, may cause the rod to slide within the keeper, allowing the door to partially open in undesirable situations and permitting extra torque to be applied to the rod.
U.S. Pat. No. 5,454,143 (hereinafter referred to as '143) consists of a horizontal brace, which is slideably and rotatably inserted into a floor plug. When the door opens against the device, it rotates in the floor plug until the horizontal brace is in planar contact with the door. The '143 invention has no locking mechanism, so an intruder may reach around a door that is slightly open with an arm or possibly a long instrument and unfasten the device. For this reason, the device is ordinarily disposed at the hinge side of the door. However, when the brace is located at the hinge side of the door, it does not provide as much torque to counteract the opening of the door. The invention also discloses a “dispersion plate” mounted onto the door, which is claimed to protect the door from damage caused by the brace. The dispersion plate will not do much to disperse the force as the invention claims, because the dispersion plate shown in the disclosure is not much larger than the horizontal brace itself. The '143 invention also suffers from the drawback that there is no effective place to store the bracing device when it is not in use. The bracing device must be detached from the door and may be hung on a hook. This requires the person to bend approximately to ground level to activate or deactivate the lock. In addition, the '143 invention does not disclose a mechanism of locking the door in its closed position.
U.S. Pat. No. 5,531,490 (hereinafter referred to as '490) discloses an “S-shaped” pivot bar, one end of which is inserted into a floor plug while the other end is allowed to translate horizontally within a brace on the interior surface of the floor. As one end of the pivot bar translates along the interior surface of the door, the pivot bar rotates and the door is allowed to open slightly. The major disadvantage with the '490 invention is that it requires extensive modification to the door to provide a gap thereunder. The gap is required to allow the horizontal cross-piece of the pivot bar to rotate under the door. Not only does this gap involve extensive installation procedures and expense, it also permits an intruder to extend an elongated instrument under the
Dorsey Dennis L.
Friedman Carl D.
Kaser Bruce A.
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