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FIELD OF THE INVENTION 
     This invention relates to sheltering structures particularly for protection against hurricanes, tornadoes, squalls and the like. 
     BACKGROUND OF THE INVENTION 
     Storms, hurricanes, typhoons, tornadoes and the like are devastating to building structures. In the United States, wind damage to building structures result in numerous injuries and deaths each year. Moreover, these storms also cause millions of dollars in property losses each year. Hurricane Andrew, which struck Florida in 1992, caused numerous injuries and deaths as well as an estimated $100 million in damages to residential homes alone. Even in the heaviest hit areas in Florida, however, where wind speeds exceeded 150 Knots, reinforced structures withstood the wind far better than non-reinforced structures. 
     Much of the wind damage to the structures occurred at “weak links” of the building structure, namely the junction between the roof and vertical support structures, i.e., walls. Another “weak link” of the building structures most affected by the storm, was the nailedsecured joints, i.e., where the aluminum siding attached to the outside of the structure or a joint securing one piece of material to another. When wind is able to get under these “weak links,” as one is weakened, additional pieces that are attached are also weakened, causing the integrity of the structure to be compromised and sometimes totally destroyed. 
     In addition to winds causing damage to the outside of a structure, high velocity winds can also destroy a structure from the inside out. For example, if any of the openings in a structure are breached, the high velocity force of the winds entering the structure create positive pressure against the roof weakening the structure. At the same time the high velocity of the winds streaming over the roof on the outside creates a suction. This combination of internal positive pressure and external suction will inevitably tare the roof off of the house. 
     In an effort to prevent the breach of openings in the structure as well as, to protect windows and doors against shattering from debris colliding at high velocity, homeowners and businesses usually board-up openings with various types of panels when there is a threat that the weather pattern will bring high velocity winds. In the case of certain types of wind driven storms, i.e. squalls and tornadoes, however, the landowner may not have sufficient time to secure windows and doors from eminent destruction. Thus, in this situation the structure is left unprotected and is vulnerable to the force of the high velocity winds generated by the fast approaching weather pattern. 
     In cases where landowners have enough warning and are able to protect the openings in the structure, in many instances, corrugated metal panels are fastened over the openings by top and bottom rails which remain in place at all times even in non-hurricane seasons. Of course, the rails are very unsightly and distract from the clean lines of a structure. Other panels are fastened to the openings by screws screwed into permanent anchors which are placed into the flush walls surrounding the openings. These again are permanent installations that are very unsightly, are subject to corrosion, and potentially represent another “weak link” that may be affected by high velocity winds. 
     In addition, hurricane force winds of one hundred miles/hr and higher are known to set up harmonic vibrations that will result in rattling loose the above described installation because of the metal to metal contact between the fasteners and the corrugated metal panels. Further, anchors of various types are also prone to failure because of progressive corrosion in coastal areas. In addition, anchors driven into blocks which are hollow and only ½ inch thick are inadequate to hold a large force form shaking loose during a major storm. 
     In a residential setting where the resident decides to nail protective covers, i.e., plywood sheets, to the side of the house, most homeowner have no experience in nailing into concrete and any nailing close to the edge of an opening will simply break the block away behind the panel and any anticipated holding power is greatly diminished from this common mistake. Even assuming that the homeowner is able to nail the protective covers to the side of the house, there will always be at least one opening unprotected so as to provide for egress. This one opening when breached is enough to cause the internal positive pressure discussed above. Moreover, the nailed protective covers add additional “weak links” to the structure which are vulnerable to high velocity winds. In addition, although the techniques discussed above may provide some protection to a structure against high wind velocity, these techniques do not protect the walls and roofs of the structure. These sections of the structure remain vulnerable to the high velocity winds. 
     In view of the problems associated with the foregoing, there is a need for a protection system for building structures that is easy to implement, can withstand high winds, reduce the number of “weak links” in a structure, and protect a structure against destruction during high wind situations. 
     SUMMARY OF THE INVENTION 
     The present invention provides an interlocking roof and wall system for protecting a building structure. The interlocking roof and protective wall system comprises a plurality of supports that form downward facing open channels which are either already attached o an overhang or for existing roofs are attachable to the overhang. For the purpose of this application the term “interlocking” means any system where one piece fits into another. The plurality of protective walls that interlock into the overhang surround the building structure, a portion of the walls fit into the channel formed by the supports. The interlocking roof and protective walls can be secured in place by additional mechanisms or can simply lie within one another. 
     Surrounding at least a portion of the plurality of protective walls is a plurality of retainer walls. The retainer walls form a cavity which is at least partially below grade wherein the protective walls are positioned within. At the base of the protective walls is a hydraulic lifting system that is in contact with a portion of the protective walls. The hydraulic lifting system is actuable to extend a member which pushes against the protective walls, thereby lifting the protective walls out of the cavity formed by the retainer walls. The protective walls are lifted to a height whereby at least a portion of the protective walls interlock in the downward facing open channel attached to the overhang of the roof. 
     After the storm is over, the protective walls can be lowered back into the cavity formed by the retainer walls by releasing the hydraulic fluid from the pressurized cylinders, causing the protective walls to slowly disengage from the interlocking supports and rest in the cavity. 
     This system can be installed at the time of construction or can be retrofitted to most existing building structures. It is understood that some building structures may need additional construction, i.e., building an overhang, for the system to work. 
    
    
     BRIEF DESCRIPTION OF THE FIGURES 
     FIG. 1 illustrates a cross-section of a structure incorporating the protectable building system of one embodiment of the invention. 
     FIG. 2 illustrates a cross-section of a structure incorporating the protectable building system showing the hydraulic system of one embodiment of the invention. 
     FIG. 3 illustrates a cross-section of a structure incorporating the protectable building system showing the roof overhang support of one embodiment of the invention. 
     FIG. 4 illustrates cross-section of a structure incorporating the protectable building system of an alternative embodiment of the invention. 
     FIG. 5A is a cutaway view of a roller and ratchet mechanism of one embodiment of the invention. 
     FIG. 5B is a cutaway view of a roller and ratchet mechanism of an alternative embodiment of the invention incorporating a cross-sectional view of the roller and ratchet mechanism. 
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
     According to one embodiment of the present invention, a protectable building system  10  that has the appearance of a conventional house is depicted in FIG.  1 . The protectable building system  10  may have a slab  15  foundation which is not required for the operation of the protectable building system, but is an easy construction method for building the structure. In addition to making construction easier, the slab  15  provides additional support for the protectable building  30  as well as protective walls  20  and  25  (described below). 
     The protectable building system  10  may be constructed on site, or may be a prefabricated modular design which is assembled on site. The protectable building system  10  is used as an illustrative example of the present invention which includes protectable building structures other than residential houses, such as commercial buildings. 
     Surrounding the protectable building structure  30  are protective walls  20  and  25 . Protective walls  20  and  25  are spaced far enough away from the protectable building  30  so that when the protective walls  20  and  25  are extended (described below) there is ample clearance of any projections extending from the protectable house i.e. window frames, extended bay windows, or air conditioners. The preferable space between the protectable building  30  and protective walls  20  and  25  is between about 1 to about 4 feet, most preferably between about 1 to about 2 feet. 
     The protective walls  20  and  25  are constructed from material that is strong enough to withstand forces placed on the walls by high velocity winds. The width of the protective walls  20  and  25  vary according to the material used for its construction. In other words, the stronger the material, the thinner the wall; the weaker the material, the thicker the wall. The combination of material and thickness used, however, must be able to withstand forces associated with a wind velocity up to about 85 mph, preferably up to about 100 mph, more preferably up to about 150 mph. 
     The height of the protective walls  20  and  25  vary with the height of the structure being protected. Preferably the protective walls are at least about 1 to about 3 feet higher than the height of the structure being protected. The portion of the wall in excess of the height of the structure remains below grade even when the protective walls  20  and  25  are fully extended (described below). The portion of the protective wall that remains below grade provides additional support to the protective walls. In other words, if the protectable building structure  30  is about 15 feet above grade, the protective walls  20  and  25  are about 16 to 18 feet height. When these walls are extended to reach the roof (as described below) at least about 1 to about 3 feet remains below grade as support. 
     In one embodiment, surrounding the protective walls  20  and  25  are first and second retainer walls  35  and  40 , respectively. The first retainer wall  35  is located closest to the protectable building structure  30  and second retainer wall  40  is furthest from the building structure  30 . The width of the cavity formed by the space between the first and second retainer walls is greater than the width of protective walls  20  and  25  so that the protective walls fit within the first and second retainer walls  35  and  40 . The first and second retainer walls  35  and  40  can be constructed from treated plywood, PVC, plastics, corrugated steel or the like. The number of retainer walls needed is directly proportional to the nuinber of protective walls needed to protect the building structure. In other words, if the size or shape of the structure requires additional protective walls, the number of retainer walls is also increased. 
     The protective walls  20  and  25  are in contact with a hydraulic system  45  which is used to raise the protective walls  20  and  25  towards the roof. The hydraulic system  45  exerts an upward force against a lifting plate  50  which is embedded at the base of protective walls  20  and  25 . The lifting plates  50  can be made of steel or any other material capable of enduring an upward force equal to or greater than the force exerted back on the plate by the weight of the wall. The hydraulic system  45  also includes at least two pressurizes cylinders shown in FIG.  2 . The pressurized cylinders may be located inside the protective walls or outside the protective walls. FIG. 2 illustrates hydraulic cylinders that are located inside the protective walls. 
     In FIG. 2 a pressurized cylinder  55  is shown in the unextended and extended view. The pressurized cylinder  55  shows the base  60 , a boom  65 , and a top  70 . The pressurized cylinders located within protective walls  20  and  25  do not require a lifting plate. The pressurized cylinder  55 , can be activated by either air or fluid. The boom  65 , whether located inside the protective walls or outside the protective walls, desirably has three stages and is capable of extending a height at least equal to the height of the protectable building structure  30 . 
     In one embodiment illustrated in FIG. 2, the pressurized cylinders are located outside the protective walls and the top  70  of boom  65  is anchored to the lifting plate  50  located at the bottom of the protective walls. The lifting plate located on the top portion of the pressurized cylinder is attached flush against the underside portion of the lifting plate  50 . Desirably, lifting plate  50  includes a depression into which the top portion of the pressurized cylinder  55  is attached. The depressed portion of the lifting plate  50  provides additional lateral strength to the connection between the pressurized cylinder  55  and lifting plate  50 . This connection prevents slippage of the pressurized cylinder  55  when the hydraulic system  45  is applying lifting forces to the lifting plate. 
     The hydraulic system also includes a pressurized hydraulic line  75  which extends from a pump  80  to an inlet valve  85  (FIG. 3) located at the base  60  of the pressurized cylinder  55 . At least four pressurized cylinders positioned beneath the protective walls  20  and  25  are required to lift the protective walls from the cavity to protect a four sided building structure. Additional protective walls and pressurized cylinders may be required to accommodate uniquely shaped structures, i.e., structures having a shape different than a square or a rectangle. 
     When the pump  80  is activated, fluid or air is pumped into the inlet valve  85  in the base  60  of the pressurized cylinder  55  and the boom  65  begins to rise. The boom  65  provides an upward vertical force on the lifting plate  50 , thereby lifting the protective wall above grade. In one embodiment, the hydraulic cylinders are equipped with the control valves that maintain the hydraulic cylinders at a predetermined height until the locking control valves are deactivated and the hydraulic cylinders lowered to a resting position. The pump  80  can be powered by electric and can be connected to a back-up 12-volt battery in case of power failure. In the alternative the pump can be powered by a gas generator. 
     FIG. 3 illustrates one embodiment where the roof  90  of the protectable building structure  30  has a overhang  95 . Attached to the underside of the overhang  95  is a support  100  forming a downward facing channel  105 . The downward facing channel  105  has a width that is greater than the width of the protective walls  20  and  25  so that the top portion of the protective walls fit within the channel  105  of the support  100 . In one embodiment, the top portion of the protective wall has a cut-away portion (not shown) that interlocks into the channel  105  of the support  100  whereby the outside portion of the support is flush with the outside portion of the protective walls  20  and  25 . This arrangement reduces the production of “weak links” discussed above, which in turn reduces the chance of high velocity winds can weakening the building structure. The supports  100  can be made of a reinforced material such as corrugated galvanized metals, reinforced wood, or the like. In any case, the supports  100  must be strong enough to both support the protective walls  20  and  25  and to prevent the roof from disconnecting from the building structure, when subjected to high velocity winds. 
     In one embodiment of the present invention, the supports  100  are located at the outermost portion of the overhang  95 . Positioning the supports  100  at the outermost portion of the overhang  95  reduces the amount of the overhang that is exposed to the high velocity winds once the protective walls  20  and  25  are in place. In other words, the outside surface of the protective walls  20  and  25 , once positioned into the supports  100 , sit flush against the rim of the overhang  90  thereby exposing little if any of the overhang  95  to the high velocity winds. Since winds can easily get under the rim of the overhang  95  and pry the roof from the building structure, reducing the exposure of the overhang  95  to the winds reduces yet another “weak link” in the building structure. 
     The supports may be equipped with a locking mechanism that interlocks the top portion of the protective walls into the supports. The locking mechanism (not shown) can be manually or automatically engaged once the top portion of the protective walls comes in contacts with the support. When fluid is drained from the hydraulic cylinders the locking mechanism can be manually or automatically disengaged so as to permit the protective walls to be lowered back into the cavity formed by the reinforced walls. 
     Since the protective walls  20  and  25  are usually heavy, one embodiment is equipped with one or more guide posts that are position in close proximately to the protective walls. These guide posts  110  shown in FIG. 4 provide strength and rigidity to the protective walls and are used to maintain the path of the walls as they are lifted and lowered. The guide posts  110  as well as the protective walls  20  and  25  are anchored in caissons  115 . Illustratively, the caissons  115  are concrete caissons made by pouring cement into cylindrical sona tubes made of waterproof cardboard which act as a mold and disintegrate over time. 
     The caissons  115  begin at the existing grade level and extend below ground a distance dictated by the soil density and size/height of the protective walls  20  and  25 . Preferably, the distance is at least about 2 to about 5 feet below the existing grade level. The soil and protective wall size also dictate the size of the caissons  105  as well as the guide posts  110 . Preferably, the diameter of the caissons  115  is about twice the diameter of the guide posts  110 . Illustratively the guide posts  110  are 4″×8″ steel H-beams which may be galvanized to prevent corrosion, and the diameter of the caissons  115  is about 16″, being twice the 8″ dimension of the guideposts  110 . 
     FIG. 5A illustrates one embodiment wherein the guide posts  110  work in conjunction with roller guides  120  and a ratchet mechanism  115 . The protective walls  20  and  25  have rollers  125  which roll along the guide posts  110  during vertical movement of the protective walls, i.e., when the hydraulic cylinders are activated. Below the rollers  125 , the ratchet mechanism  115  is located between the protective walls  20  and  25  and the guide post  110 . The ratchet mechanism  115  permits the protective walls  20  and  25  to rise along the guide posts  110  as the boom of the hydraulic cylinder is extended and prevents a accidental lowering of the protective walls. The roller  125  is attached to the outer surface of the protective walls  20  and  25 . The ratchet mechanism  115  has two parts. The first part is attached to the guide posts  110  and the outer surface of the protective walls and the second part is attached to the outer portion of the protective walls. Each guide post  110  has its own ratchet  115  and roller  125  mechanism. The rollers  125  roll along the larger section of the guide post  110 . The rollers  125  may be bolted or anchored into the protective walls  20  and  25  using bolts, two J-hooks or a single U-shaped J-hook (not shown). The rollers  125  maybe rubber, Teflon™, hard plastic or rubberized metal. Illustratively in FIG. 5B, the rollers  125  are located above the ratchet mechanism  115 . Alternatively, the rollers  125  may be located adjacent to the ratchet mechanism  115 . This allows the first part of the ratchet mechanism  115  to extend further up the guide post  110 , thus permitting the protective walls  20  and  25  to remain locked in place at a higher height. The ratchet mechanism  115  keeps the protective walls  20  and  25  in an elevated position after the protective walls have been raised by pressurized cylinders. 
     The first part of the ratchet mechanism  115  is attached to the guide post  110  via bolts, welding or the like. The first part of the ratchet mechanism  115  has fixed teeth  140  separated by segments. The second part of the ratchet mechanism  115  has a body which is attached, e.g., bolted, to the outer surface of the protective walls  20  and  25  with bolts. In addition, the second part of the ratchet mechanism  115  has a locking lever  130  which is attached to the body via a hinge  135  located at the top of the movable tooth  145 . The fixed teeth  140  of the first part mate with the movable teeth  145  of the second part to prevent a premature lowering of the protective walls  20  and  25 . In other words, the surfaces  155  of the movable teeth and the surfaces  145  of the fixed teeth  150  complement each other so as to temporarily lock together. This ratchet system allows the protective walls  20  and  25  to rise but prevent them from descending. Preferably, the surface  155  of the movable teeth  145  has a downward slant and the surface  150  of the fixed teeth  140  have an upward slant. This provides a better locking of the first and second parts of the ratchet when the surfaces  155  of the movable teeth  145  mate with the surfaces  150  of a fixed teeth  140 . In one embodiment, the movable teeth  145  of the second part are pushed forward by a spring loaded rod (not shown) which is attached to the back of the movable teeth  145 . 
     The ratchet mechanism  115  can also be equipped with a locking lever  130  that locks the ratchet mechanism  115  in place when the walls are stationary in the raised position. The locking lever  130  can be attached to an emergency locking lever release cord that releases the ratchet mechanism  115  when it is pulled away from the protective walls. In other words, the locking lever  130  disengages from the fixed teeth  140  and the protective walls  20  and  25  are free to move in the vertical position. Upon releasing the locking lever, fluid, i.e., gas or oil, can be released from the pressurized fluid resulting lowering of the protective walls into the cavity formed by the first and second retainer walls  35  and  40 . 
     The operation of the protective wall system is as follows. In the event of an approaching weather front with sustained winds greater than 50 mph, the hydraulic lifting system  45  can be activated to lift the protective walls  20  and  25  into position. When the hydraulic system is activated a pump, which is attached to the pressurized cylinders  55  via a pressurized hydraulic line  75 , begins to pump fluid into the pressurized cylinders  55 . The pump  80  is attached to a flow divider (not shown) by connecting lines. The flow divider evenly distributes the fluid pumped by the pump to the pressurized cylinders  55 . As the pressured cylinders begin to fill with fluid, the booms begin to extend out of the pressurized cylinders and exert an upward force on the protective walls. As shown in the figures, the boom  65  may be located within the protective walls  20  and  25  or positioned so that a portion of the boom  65  is in contact with a portion of the protective walls  20  and  25 . When the boom is outside the protective walls, the portion of the protective walls that experience the bulk of the stress due to the upward force is further supported by a lifting plate  50 . If the boom  65  is inside the protective wall, no lifting plate is necessary. As a result of this upward force, the protective walls  20  and  25  rise out of the cavity formed by the first and second retainer walls  30  and  40 . In one embodiment, the walls are guided by several guide posts  110  that provide support as well as guidance for the vertical movement of the rising walls. In another embodiment no guide posts are utilized. 
     When the protective walls  20  and  25  rise, the movable teeth  145  of the ratchet system attached to the guide posts  110  are pushed back toward the walls as it slides up the fixed teeth  140 . When the movable teeth  145  reaches over one of the fixed teeth  140 , the spring loaded rod pushes the movable teeth  145  forward toward the guide post  110 . This extends the movable teeth  145  over the fixed teeth  140  and prevents the protective walls  20  and  25  from accidentally lowering. The protective walls  20  and  25  are lifted until the upper portion of the protective walls fit into a downward facing channel formed by the supports  100  attached to the overhang  95  of the roof. Once at least a portion of the protective walls fit into the downward channel  105  of the supports  100 , the protective walls  20  and  25  enclose the building structure  30  and protect it from high velocity winds. Once the walls are in this position, the pressurized cylinders  55  are locked in place by the ratchet mechanism  15 . 
     After the winds diminish, in order to allow a lowering of the protective walls  20  and  25  of the embodiment containing guide posts  100 , the movable tooth  145  that is in the locked position is manually pulled back and locked in a recessed position. Illustratively, a release cord  165  (FIG.  5 A), which may be constructed of braided rope or metal mesh, has one end attached to the spring loaded rod and the other to a handle. Alternatively, the spring loaded rod can be dispensed and the release cord  165  directly attached to the movable teeth  145 . In this embodiment, instead of the spring being coiled around the rod, it is coiled around a portion of the release cord  165  which is between the outer surface of the protective wall  20  and  25  and the movable teeth  145 . The spring, whether it is coiled around the braided rope or the rod has a diameter larger than the diameter of the hole that the braided rope and the rod pass through. This keeps the spring between the outer surface of the wall  20  and  25  and the movable teeth  145 . Alternatively, or in addition to the spring, the hinge  135  of the movable teeth  145  may be spring loaded to bias the movable teeth  145  in the forward direction toward the guide post  110 . The movable teeth  145  is recessed back by pulling on the handle. To lock the movable teeth  145  in a recessed position, the handle is hooked on the protrusions attached to the inner surface of the protective walls  20  and  25 . 
     In an alternative, a safety pin  160  (FIG. 5A) may be inserted in a hole of a fixed plate positioned on the side of the movable teeth  145 . The fixed plate (not shown) is located at the other side of the movable teeth  145 . When the safety pin  160  enters the hole in the fixed plate, the movable teeth  145  is locked in a recessed position. When the movable teeth  145  are locked in this position, the protective walls  20  and  25  can freely slide down the guide posts  110 . 
     The movable teeth  145  may be pulled back easily when it is located along the segments between two of the fixed teeth  140 . However, pulling back the movable teeth  145  is nearly impossible when it is resting on the fixed teeth  140 , supporting the weight of the protective walls  20  and  25  and preventing it from lowering. Therefore, to be able to pull back the movable teeth  145  while it is supporting the weight of the protective walls  20  and  25 , it is necessary to lift the protective walls  20  and  25 . This removes the weight of the protective walls from the movable teeth  145  so that it may be pulled back to the recessed position. The protective walls may be lifted using the pressurized cylinders  55 . The protective walls  20  and  25  need only be lifted approximately ¼ inch in order to release the engagement of the movable teeth  145  into the fixed teeth  140  and allow the protective walls to lower back into the cavity formed by the reinforced walls. 
     In the embodiments that are not equipped with guide posts, the protective walls are lowered by simply releasing the fluid from the hydraulic cylinders so that the boom begins to lower. When substantially all the fluid is released from the hydraulic cylinders, the boom is in the resting position. To lift the boom, fluid is again pumped into the hydraulic cylinders. 
     While the invention has been described by the references to specific embodiments, this was for the purposes of illustration only and should not be construed to limit the spirit or the scope of the invention. Numerous alternative embodiments may be devised by those skilled in the art without departing from the spirit and scope of the following claims.

Summary:
An interlocking wall and roof system for the protection of a building structure is disclosed. The interlocking roof and wall system is equipped with a plurality of supports that form downward facing open channels that are either already attached to the overhang of the roof or are easily attachable to the overhang. The system also includes a plurality of protective walls that surround the building structure. The protective walls can be lifted from a resting position to a position where at least a portion of the walls fit into the downward facing open channels of the overhang. These walls are lifted by a hydraulic lifting system. The invention also provides a complete building structure already fitted with the supports, hydraulic lifting system and protective walls.