1. Field of the Invention
The present invention relates generally to frames that support glazings, and more specifically, relates to a method and apparatus for an improved system for supporting a glazing.
2. Description of the Related Art
In an increasingly violent society, businesses and homes are subject to an increased number of threats against both life and property. These threats to life and property can include ballistic threats, threats of explosive blasts, forced entry threats, and others.
Businesses and homes in areas of high crime are increasingly forced to employ security measures to protect against these threats. These security measures include the installation of glazings with increased strength. For example, bullet resistant glazings or glazings that can resist certain explosive blast threats are finding their way into both residential and industrial buildings.
Additionally, buildings in areas that are subject to natural disaster, such as hurricanes, tornadoes and severe storms, require weatherproofing and additional protection from the elements.
Unfortunately, conventional security improvement schemes require that the existing window and frame be removed and replaced with a new glazing unit and a new frame. Because the old windows and frames need to be removed first before the new windows and frames can be installed, the costs of such a job are greatly increased. Moreover, the area downtime, that is, the time required for workmen to come in, tear down the existing structure, and install the new structure, is also substantial. Furthermore, there is a risk of contamination to the work-area resulting from the demolition and reconstruction of the frame and surrounding building structure.
Another disadvantage of conventional schemes is that the noise, commotion and disruption inherent in tearing out the old frame and existing building materials, in addition to the significant down-time, precludes a discreet security enhancement. Because of the conspicuous nature of conventional schemes, they may unnecessarily cause fear in the workplace or unwittingly reveal to third parties the additional security measures.
Also, the conventional technique for increasing the security of a building is time-consuming and costly, requiring substantial lead time for pre-fabrication of the new frame prior to installation.
Furthermore, conventional retrofit methods for increasing the security of a building cannot be aesthetically finished and leave unsightly anchoring, such as screws or other evidence of sizing the frame (e.g., cut marks, edges, scratches). Once the new window glazing is in place, conventional frames do not allow for upgrades to glazings with a greater thickness. In order to upgrade with conventional frames, the entire frame must be removed and a suitable frame having dimensions to accommodate the glazing having a greater thickness must be installed.
Another disadvantage is that conventional frames and methods to install them are costly, time-consuming, and require two or more workers to aid in positioning the glass or glazing in the frames.
Conventional frames are not designed to withstand both the positive phase and negative phase of an explosive detonation (explosion). The positive phase of an explosion is characterized by highly compressed air traveling radially outward from the source of the explosion at supersonic velocities. The negative phase of an explosion is characterized by the shockwave falling below surrounding atmospheric pressure creating suction. Behind the shockwave, a vacuum is created and air rushes in to fill the vacuum creating high intensity wind or drag pressure on the surfaces of buildings and other structures.
A well known standard for grading the blast resistant quality of a window system is the Protection Level ratings established by the Government Services Administration (GSA) for federal facilities. Based upon reproducible tests performed by the U.S. Army Corps of Engineers, Table I identifies the ratings and security criteria of the GSA. These levels of protection are for positive over blast pressure only, and do not account for fragmentation and/or shrapnel impacts.
Accordingly, there remains a need in the industry for an improved window system and a method of installing the improved window system that overcomes the disadvantages set forth above.
Various embodiments are illustrated by way of example and not by way of limitation in the figures of the accompanying drawings in which like references indicate similar elements. It should be noted that references to “an,” “one,” or “various” embodiments in this disclosure are not necessarily to the same embodiment, and such references mean at least one.
In one embodiment an improved window system can be coupled to the sill 18, the king studs 22 and 26, and the header 30 as a secondary window to the existing glazing 40. In another embodiment, an improved window system replaces the glazing 40.
In one embodiment, the anchor tube 202 is rectangular in shape longitudinally and hollow. The anchor tube 202 has an increased wall thickness adjacent to the frame 204. The increased thickness of the wall in this portion of the anchor tube 202 improves the strength of the anchor tube 202 as a mounting point for the frame 204 and as a strong point for the locking mechanism 208 to engage. In one embodiment, the increased thickness of wall provides for a strong point that a hinge 206 and lug pins (not shown) can anchor into. The anchor tube 202 is designed to resist tearing or stretching of the fabrication material during the positive blast pressure phase of an explosion, and to resist forced entry, prying and bending of the window system 200. In one embodiment, the anchor tube 202 is composed of aluminum 6063-T5 or similar material. Use of aluminum 6063-T5 makes the anchor tube 202 of lighter weight and consequently easier to install and less expensive than a steel anchor tube.
In one embodiment, the anchor tube 202 is designed to be physically attached to an existing window frame 38 or to the casing of a window opening or similar structure. The anchor tube 202 is attached to a building by anchors from four inches to twelve inches from center through existing frames, casing materials or like structures and further is mounted to the structural framing members of the building structure. The spacing of the anchors is dependent on the nature of an anticipated threat. Closer spacing is used for higher threats.
The anchor tube 202 is attached to a building material in such a way as to reinforce the existing frames by either anchoring through the frames or by providing a substantial stopping mechanism directly behind the safe side or inside the existing frame. In one embodiment, this is accomplished by having the anchors located from four to twelve inches from center, dependent upon the type of anticipated threat. The greater the explosive threat, the closer the anchors are placed to each other. The anchors are mounted through the thickest portion of the anchor tube 202. In one embodiment, a brace bar is used to reinforce against lateral tearing of the anchor tube 202 by inserting the brace bar into the anchor tube 202 interior adjacent the portion with thicker walls.
In one embodiment, the frame 204 is fabricated as a roughly rectangular structure with one side extending to define a portion of a channel for housing a glazing 210. The frame 204, also defines a trench for attaching a glazing stop 312.
In one embodiment, illustrated in
In one embodiment, a stop rail 316 is mounted on the anchor tube 202 adjacent the frame 204 on the threat side of the window system 200. The stop rail 316 defines a T-section space that holds a stop vinyl 318. The stop rail 316 limits lateral movement of the frame 204 toward the threat side. The stop vinyl 318 seals the frame 204, preventing airflow between the frame 204 and anchor tube 202. The stop rail 316 and stop vinyl 318 limit the lateral movement of the frame 204 to prevent over-extension during normal use. In addition, the stop rail 316 and stop vinyl 318 provide support to the frame 204 during the negative phase of an explosion to prevent failure due to pull out of the hinged frame 204 toward the exterior of a building. The stop rail 316 and stop vinyl 318 also relieve stress from the multi-point locking system 208 during the negative phase of the explosion.
In one embodiment, the stop rail 316 is composed of aluminum 6063-T5 or similar material. Use of aluminum 6063-T5 makes the stop rail 316 of lighter weight and consequently easier to install and less expensive than a steel stop rail. In one embodiment, the stop vinyl 318 is composed of extruded virgin vinyl or similar materials. Virgin vinyl maintains elasticity and shape well over time and in the presence of Ultra Violet (UV) energy sources.
In one embodiment, the window system 200 is designed to accommodate a glazing 210 having a thickness from ¼ inch to 13/16 inch. Various types of glazings can be used such as all laminated glass, glass clad polycarbonates, laminated polycarbonates, monolithic polycarbonates, acrylic/glass/polycarbonate hybrids and similar glazings. The type and thickness of glazing 210 used in the window system 200 determines the explosive blast over pressure resistance, based on varied charge weight configurations, stand off distances, and explosive types. In one embodiment, the glazing 210 is designed to resist forced entry threats, ballistic threats and natural disaster threats. Additionally, specific glazings also have greater resistance to explosive blast encasement fragmentation and other shrapnel associated with explosive blasts that could cause failure of the glazing 210 before the positive phase of an explosion.
Table II shows the force resistance for various thickness of laminated glass composites.
In one embodiment, the laminated glass composite is a polyvinylbutyral (PVB) interlayered glass, where the PVB layer is a single ply. In one embodiment, the laminated glass composite includes a polyethylene terephthalate (PET) layer. Table III shows the relation of glazing thickness to layer thickness in one embodiment of the invention.
In one embodiment, the glazing 210 is lightweight making it suitable for use in structures that require an improved window system that is sufficiently light while meeting security standards such as the various Protection Levels defined by the GSA, the UL 972 Burglary Resistance Standard and Dade County Hurricane Standard. Table IV identifies the weight and force resistance of a glazing 210 of a nominal thickness.
In one embodiment, the arresting cable 1132 is composed of stainless steel or similar material. The use of stainless steel provides high strength coupled with non-corroding or rusting quality, thereby eliminating precipitation creep common in metal reinforced safety glazings. The arresting cable 1132 is laid into a set of grooves cut into the safe side of glazing 210 and held in place by the adhesion of a PVB and PET coating. This coating provides scratch and abrasion resistance and the combined laminate is a spall lining. A spall lining precludes crushed or broken glass from separating from the glazing and entering the safe area of a building.
In one embodiment, the hinge 206 and lug pins 1238 are attached to a brace bar 1236. The brace bar 1236 is manufactured of a solid high strength structural aluminum alloy such as structural aluminum 6061-T6 or similar materials. The brace bar 1236 serves as a locking and pullout resistant mount. The brace bar 1236 is located within the frame 204.
In one embodiment, the glazing assembly includes tape 1240 placed in the glazing channel between the glazing 210 and the frame 204. A second layer of tape 1240 is placed in the channel between the glazing 210 and the infill bar 314. A third layer of tape 1240 is placed in the glazing channel between the infill bar 314 and the glazing stop 312. Spring pins 442 are coupled to the glazing stop 312 to secure the glazing stop 312 in the trench of the frame 204.
In one embodiment, the tape 1240 is a closed cell very high bond acrylic high density tape with Ultra Violet resistance and resistance to moisture, solvents and plasticizer migration. In one embodiment, structural liquid adhesives or similar materials having an ultimate tensile strength of 335 to 350 PSI, an ultimate elongation percentage of 300 to 525 percent, Ultra Violet resistance, movement capability in the range of ±25 to 50 percent, a tensile strength at 100 percent elongation of 90 to 175 PSI and a durometer hardness of Shore A scale 35 to 40 is used in place of or in combination with tape 1240.
In another embodiment, the window system 1800 may be modified to withstand blast pressures of up to 40 PSI or greater. Thicker glazings are used that are up to approximately 2.75 inches in thickness. The dimensions of frame 204 and anchor tubing 202 are modified proportionately. The overall depth of the window system 1800 increases to up to 3.25 inches. The depth of the channels in which the glazing 210 rests also increases in height. Locking pins 1238 which are ⅜ inch in diameter for embodiments designed to withstand blasts of 15 PSI or less are increased to ½ inch in diameter to withstand blast pressures greater than 15 PSI.
Method of Installing the Present Invention to Existing Building Materials
Fastening means or anchoring means used herein can include, but are not limited to, threaded fasteners such as nuts and bolts, screws, adhesives and epoxies, hooks, rivets, welding, surface tension, steel shaft rivets, wedge or sleeve expansion anchors, coil-loop or epoxy anchors, etc.
In the one embodiment, the anchor tube 202 frame 204, infill bar 314, brace channel 926, glazing stop 312 and brace bar 1236 are manufactured by an extrusion process and are manufactured from aluminum. For straight portions, to be used in rectangular or square windows, aluminum 6063-T5 is used. For windows having non-straight portions (e.g., circular windows or arched windows), the aluminum 6063-T1 may be used. The aluminum 6063-T1 provides additional malleability so that the material can be formed into curved portions. This forming adds to the material strength using the work hardening process incurred through the bending and shaping of the lowered temperature aluminum (6063-T1) resulting in strengths equivalent to aluminum 6063-T5.
In the foregoing specification, the invention has been described with reference to specific exemplary embodiments thereof. It will, however, be evident that various modifications and changes may be made thereto without departing from the broader spirit and scope of the invention. The specification and drawings are, accordingly, to be regarded in an illustrative rather than a restrictive sense.
The application is a Continuation-In-Part of application Ser. No. 10/196,774, filed Jul. 15, 2002 now abandoned by applicant, Murray L. Neal entitled “Explosion Resistant Window System.”
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Number | Date | Country | |
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Parent | 10196774 | Jul 2002 | US |
Child | 10241906 | US |