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BACKGROUND OF THE INVENTION 
     In U.S. Pat. No. 4,286,613 granted on Sep. 1, 1981 to Marvin Lacoste, mention is made of allowing taps or faucets to drip thus preventing plumbing from freezing by allowing slow flow of water therethrough. If such taps are not opened in time or enough, damage to the water system, particularly through burst pipes, occurs. As a result of such ineffective efforts, a variety of automatic opening devices exist in the prior art. 
     One group of automatic opening devices effect automatic drip or slow water flow in associated water systems, such as U.S. Pat. No. 4,066,090 to Nakajima et al. and U.S. Pat. No. 3,369,556 issued to Allderdice on Feb. 20, 1968. 
     Other automatic opening devices automatically drain all water from the plumbing of associated water systems, such as U.S. Pat. No. 3,320,965 to Morgan, U.S. Pat. No. 1,820,473 to Milone and U.S. Pat. No. 1,558,276 to Peterson. 
     In many such water system freeze protecting devices, bellows are utilized, and, depending upon the specific type of device or its geographic location, the bellows might be filled with water which will freeze to ice or might be filled with a fluid, such as Freon or a Freon-gas mixture which contracts as the temperature drops and expands as the temperature rises. In either case, the bellows is associated with a valve for draining the particular water system. Unfortunately, each year though the cold months numerous water pipes freeze, burst, and thereby cause considerable damage, particularly in single family homes and residences. As an example of such damage, in 1996 nearly 20,000 State Farm policy holders in the United States and Canada suffered water damage to their homes (or apartments) because water pipes froze and burst. State Farm paid almost $57,000,000.00 to cover such frozen pipe damage losses, an average of approximately $2,871.00 per claim. 
     Many people follow conventional tips/wisdom for preventing frozen pipes, and thus do not think frozen pipes can happen to them. Typically, a homeowner will disconnect all garden hoses and other outside hose connections; insulate all exposed pipes and crawl spaces and attics since they are susceptible to freezing, set thermostats no lower than 55° F. (12° C.) even when the home is not occupied during the winter; let water drip (particularly overnight on extremely cold nights from both hot and cold faucets located along outside walls); and open cabinet doors so heat from a room can get to non-insulated pipes under sinks or the like. Unfortunately, a sudden cold snap combined with heavy wet snows and/or freezing rain can result in downed power lines which cut off power closing down household heating systems, including the thermostats thereof, for hours or days with the result that freezing occurs in the water systems irrespective of following prudent freeze prevention measures. 
     SUMMARY OF THE INVENTION 
     A primary object of the present invention is to provide a novel automatic valve system which is connected to the main water supply line at its point of introduction into a house, an apartment or the like. The valve mechanism includes a housing having a water inlet connected to the water supply from the street, a water outlet and a main valve which is preferably locked in a first position at which a diametric port maintains the water inlet and the water outlet in fluid communication with each other. In this position water is delivered from the water outlet to sinks, toilets, water heaters, etc. A shaft connected to the main valve is normally spring-biased in a direction which would move the main valve to a second position closing off water flow between the water inlet and the water outlet. However, the main valve shaft is immobilized with the valve in the first position by a temperature sensing mechanism which includes a bellows containing Freon or similar gas or fluid which contracts as the temperature drops. The bellows carries a locking pin which seats in a notch of the main valve shaft and, thus, is retracted therefrom as the Freon in the bellows contracts under temperatures at or below freezing. Upon the retraction of the locking pin, the biasing spring urges the main valve to a closed position cutting off fluid flow between the water inlet and the water outlet. 
     Contemporaneous with the closing of water flow through the main valve, another portion of the main valve places the water outlet in fluid communication with a drain opening or drain port which is connected by a tube or conduit to a floor drain, for example. Since all plumbing in the house is connected to the main water outlet of the automatic valve mechanism, water from all of the internal plumbing drains in a reverse direction into the water outlet through a drain by-pass port of the valve and a drain outlet of the valve housing into the drain pipe and subsequently discharges into the floor drain. Accordingly, should temperature in the house drop to or substantially below freezing, all of the water in the house plumbing is drained and no damage can occur therein. Furthermore, the water inlet and the main water supply are preferably heavy insulated and rupture or pipe bursting in this area is virtually impossible. However, should even this occur, the automatic valve mechanism is located immediately in the area into which the main water supply from the street enters the home, and this is usually a basement or a crawl space or the like. Therefore, should the water inlet side burst, any water from the street would not effect the living quarters of the house but would instead drain into a crawl space or a basement, and more likely than not the latter includes a floor drain which is normally code-required. Thus, the automatic valve mechanism assures that the main water supply is not only terminated under substantially freezing water conditions, but the house plumbing is also completely drained of water thereby preventing plumbing/pipe/appliance damage. 
     With the above and other objects in view that will hereinafter appear, the nature of the invention will be more clearly understood by reference to the following detailed description, the appended claims and the several views illustrated in the accompanying drawings. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     FIG. 1 is an exploded fragmentary perspective view, and illustrates a main water supply line entering a basement and connected thereto is an automatic valve mechanism of the present invention for precluding pipes from bursting at substantially freezing ambient temperature or below. 
     FIG. 2 is a perspective view of the automatic water drain mechanism, and illustrates an axially aligned water inlet and a water outlet, a drain associated with the water outlet, and openings for permitting ambient air to enter the housing. 
     FIG. 3 is a fragmentary top plan view of the automatic water drain mechanism of FIG. 2, and illustrates a temperature sensing mechanism connected by a conduit to a bellows housing Freon and a biasing spring normally biasing a valve rod or shaft to the left. 
     FIG. 4 is a side elevational view of the automatic water drain mechanism of FIG. 2 with parts broken away for clarity, and illustrates a detent or pin engaging a notch of the valve rod to prevent movement of the latter to the left, and a manually operable pin for overriding the biasing spring. 
     FIG. 5 is a fragmentary side elevational view of the automatic water drain mechanism, and illustrates a valve housing in cross section and a valve thereof in a first position in which water flows from the water inlet through a diametric port in the valve and out the water outlet. 
     FIG. 6 is a fragmentary side elevational view with parts also shown in cross-section similar to FIG. 5, and illustrates the valve in a second position closing off water flow between the water inlet and the water outlet and placing a drain opening and drain port in fluid communication with the water outlet to drain water from house pipes/plumbing/appliances into a drain line or dump line and an associated floor drain. 
    
    
     DESCRIPTION OF THE PREFERRED EMBODIMENT 
     A novel automatic water cut-off and drain mechanism operative at low/freezing ambient temperatures to cut-off water flow and drain a water system is generally designated by the reference numeral  10  (FIG.  1 ). 
     The automatic drain mechanism  10  is best illustrated in FIG. 1 in association with a typical installation as might be found in a basement B of a residence, such as a single dwelling house, an apartment, a condominium or the like. The basement B includes a conventional wall W which might be constructed from concrete, cinder block, or a combination thereof, and a floor F, usually constructed from concrete, having a conventional floor drain D. Located in the basement B might be, for example, a conventional hot water heater H, a relatively deep wash sink S, and perhaps a clothes washer (not shown). The hot water heater H, the sink S, the clothes washer (not shown), a pedestal sink P located on the floor above the basement B and other associated water-usage appliances, such as kitchen and bathroom sinks, toilets, etc. are all interconnected by a conventional plumbing/watering system PS defined by numerous individual metal (copper) or plastic pipes or conduits C running throughout a conventional residence, including in or along walls, floors and ceilings thereof. Obviously, if any one or more of such pipes C of the plumbing system PS freezes and/or bursts under temperatures substantially at or below 32° F. (0° C.), extensive water damage more often than not would be expected. 
     The water for the plumbing system PS normally enters a residence somewhere in its basement or a crawl space associated therewith by means of a main water supply pipe or line M from a conventional street supply or a well. The main water supply line M is shown entering the basement B through the floor F, but it can as well enter through the wall W, normally sufficiently below the frost line to prevent freezing. Though not shown, the portion of the main water supply pipe M projecting into the basement B is heavily insulated after the installation of the automatic drain mechanism  10  to preclude water therein from freezing, as is essentially the entirely of the exterior of the automatic valve mechanism  10 , except for an apertured end thereof, as will be described more fully hereinafter. 
     A main gate valve G is located in a main line ML which provides water service to the entire plumbing system PS in a conventional manner. The main gate valve G is shown in its “ON” position, and when a handle (unnumbered) thereof is rotated, the main gate valve can be completely closed to prevent water from flowing into the plumbing system PS via the main line ML. 
     The automatic drain mechanism  10  includes a two-piece exterior housing defined by a first exterior housing body  11  and a second exterior housing body  21 . 
     The first exterior housing body  11  includes a rear wall  12  of a generally rectangular configuration, opposite end walls  13 ,  14 , the latter of which is provided with a plurality of circular openings or apertures  15 , a partition wall  16 , an upper wall  17  having adjacent circular openings  18 ,  19 , and a lower wall  20 . 
     The second housing wall  21  includes a relatively long rectangular front wall  22 , a top wall  23  having a generally U-shaped cut-out or slot  24  (FIG. 2) formed therein, a bottom wall (unnumbered) and opposite pairs of end flanges  25 ,  26  which slidably mate with the opposite end walls  13 ,  14  of the first exterior housing body  11 . In this manner the exterior housing bodies  11 ,  21  define a relatively closed chamber which is, however, exposed to ambient temperature within the basement B through the plurality of holes or openings  15  in the end wall  14 . 
     The automatic drain mechanism  10  further includes a valve housing  30  defined by a main substantially cylindrical valve housing body  31  defining a substantially cylindrical internal surface  32  closed at axially opposite ends by conventional threaded cylindrical and conical end caps  33 ,  34 , respectively. A water inlet port  35  carries a nut  36  and is in axial aligned relationship to a water outlet port  37  carrying a conventional threaded nut  38 . The nuts  36 ,  38  unite the valve housing  30  to the respective main water supply line M and to the main line ML in the manner clearly illustrated in FIG. 1 of the drawings. 
     A drainage port or drainage outlet  40  opens through the cylindrical surface  32  and exits through the opening  18  in the upper wall  17  of the housing  11 , and is preferably placed in liquid communication with the drain D (FIG. 1) by a clear flexible polyethylene pipe  45 . 
     A generally cylindrical valve or valve body  50  is axially slidable along the cylindrical surface  32  between a first position shown in FIG. 5 and a second position shown in FIG.  6 . The valve  50  includes axially opposite ends  51 ,  52 , the latter of which includes a threaded bore  53  into which is threaded a valve stem, shaft or rod  54  which is preferably of a rectangular transverse cross-section corresponding to a like rectangular opening  55  formed in a nut  56  which houses a washer  57  and is threaded to the conical end cap  34 . Due to the polygonal transverse cross-section of the rod  54  and the opening  55 , the rod  54  cannot rotate nor can the valve  50  carried thereby. 
     A diametrical port  60  is formed through the left end of the valve  50 , as viewed in FIGS. 5 and 6, and when in the position shown in FIG. 5, water flowing into the water inlet  35  passes through the diametric port  60  and flows into and through the water outlet  37 , as is indicated by the unnumbered headed arrow associated therewith. O-ring seals  61 ,  62  seal against the cylindrical surface  32  of the cylindrical valve housing body  31  and prevent water leakage in the position illustrated in FIG. 5 of the drawings. 
     The right-hand side of the valve  50 , again as viewed in FIGS. 5 and 6, includes an axial passage or port  70  defined in part by a curved wall  71  which extends substantially between O-ring seals  72  and  73 . Another seal  74  is carried by the cylindrical surface of the valve  50  diametrically opposite from the channel  70  and between the seals  72 ,  73 . When the valve  50  moves to the second position thereof shown in FIG. 6 under the influence of near freezing, freezing or lower than freezing temperatures in a manner to be described more fully hereinafter, the valve  50  is so positioned as to cut-off water flow between the inlet  35  and the outlet  37  (FIG.  6 ), noting that the seal  74  creates a seal with the opposing surface (unnumbered) of the port  35 , and in conjunction with the seals  72 ,  73  assure that water from the plumbing system PS flowing under the influence of gravity flows downward into the water outlet  37  (FIG.  6 ), through the channel or port means  70  and into the drain port  40  exiting therefrom into the drain line  45  (FIG. 1) and eventually dumping into the floor drain D to completely drain the plumbing system PS. 
     Means  80  (FIGS. 5 and 6) in the form of a spring surrounding the shaft  54  seats against the partition wall  16  and against a pin or washer  81  fixed to the shaft  54 . 
     As is best illustrated in FIG. 5 of the drawings, two different means  85 ,  90  are provided for selectively preventing automatically operative biasing means  80  from shifting the shaft  54  to the left, the first means  85  being a manual override of the automatic second means  90  which is operative under substantially freezing ambient outdoor temperatures to bias the valve  50  to the “dump” or “drain” position of FIG.  6 . 
     The manual override means  85  includes a lever  86  pivoted at  87  to the partition wall  16  and having an end (unnumbered) received in a notch  88  (FIG. 5) of the shaft  54  which carries an O-ring handle  89 . When the lever or detent  86  is seated in the notch  88 , the valve  50  occupies the first position thereof shown in FIG. 5 with the port  60  in diametric alignment with the inlet  35  and the outlet  37 . In this operative position of the manual override  88 , the automatic biasing means  80  is inoperative for its intended purpose irrespective of the position of a pin or detent  91  of the automatic second means  90 , as will be readily apparent immediately hereinafter. 
     The automatic second means  90  prevents the spring  80  from biasing the valve  50  from the position shown in FIG. 5 to the position shown in FIG. 6 when ambient temperatures are above freezing (32° F./0° C.), and also permits the spring  80  to bias the valve  50  to the position shown in FIG. 6 when ambient temperatures are at substantially freezing (32° F./0° C.). The means  90  includes a housing  92  suitable fixed in the position shown in FIGS. 5 and 6 to the interior of the first housing body  11  with an integral guide sleeve  93  thereof slidably receiving the pin or detent  91  in alignment with a notch  95  of the valve rod  54 . The detent  91  is carried by a hollow spring bellows  96  which is constructed to inherently return from its expanded position (FIG. 5) to its retracted position (FIG. 6) under the inherent spring-biased nature of the bellows itself. However, the bellows  96  is part of a closed fluid system which includes a pipe  97  and a conventional sensing bulb  98  located immediately adjacent the openings  15  of the end wall  14  (FIG.  2 ). The sensing bulb  98 , the pipe  97  and the bellows  96  contain Freon or a similar fluid or gas which is charged into the bellows  96  at temperatures well above 32° F. Freon or a Freon gas mixture will contract as temperature drops and, of course, expands as temperature rise. Thus, the closed-circuit system is pressurized sufficiently such that as temperature approaches 32° F., the Freon will contract, the bellows will similarly contract from the fully expanded position shown in FIG. 5, and at 31.5° F. the bellows will have sufficiently retracted to fully withdraw the detent  91  from the slot  95  resulting in the spring  80  biasing the rod  54  to the left from the first position shown in FIG. 5 to the second position shown in FIG.  6 . In the latter position, water in the plumbing system PS drains by gravity into the main house line ML, into the water outlet  37 , through the channel or passage  70  and eventually through the drain opening  40  and the drain pipe  45  into the floor drain D. Water from the main water supply pipe M is precluded from entering the valve body  31  because of the position of the valve  50  shown in FIG. 6 including the position of the seal  74  preventing water flow past the valve  50 . Thus, in the position shown in FIG. 6, the plumbing system is drained, and water from the main water supply line M cannot flow beyond the valve  50 . Furthermore, the high insulation earlier herein noted surrounding the pipes M and  35  and the automatic drain mechanism  10  (not shown in FIG.  1 ), except for the openings  15 , preclude freezing of the water therein. Thus, drainage of the plumbing system PS is assured and correspondingly water damage to the residence is precluded. 
     After the valve  50  has been shifted to the second position thereof (FIG.  6 ), should temperatures rise, the detent  91  will again move upwardly toward and against the rod  54  but will be ineffective for any purpose whatever. However, in order to re-establish water flow, the homeowner need but grasp the O-ring handle  89 , pull the rod  54  to the right, and the detent  91  will again engage in the slot  95  which once again “arms” the automatic valve mechanism  10  for subsequent operation. 
     The manual override  85  maybe maintained in its operative position (FIG. 5) during summer months to make certain that under any malfunction of the means  90 , the valve  50  will not move to the second/closed position of FIG.  6 . Since there is no particular concern of freezing during summer months, using the manual override  85  assures water flow in the event, for example, the bellows  96  might leak resulting in reduced pressure and the withdrawal of the detent  91  from the slot  95 . Thus, the automatic valve mechanism assures that the plumbing system PS is drained and also prevents water flow from the supply via the main water supply pipe M. 
     Although a preferred embodiment of the invention has been specifically illustrated and described herein, it is to be understood that minor variations may be made in the apparatus without departing from the spirit and scope of the invention, as defined the appended claims.

Summary:
An automatic mechanism is provided for cutting-off water flow to a plumbing system of a house, an apartment, a business or the like, while at the same time draining water/plumbing systems when subjected to low/freezing ambient temperatures. The mechanism includes a valve body housing a reciprocal valve which is operative to place an inlet and an outlet in fluid communication while cutting off a drain port, and in a second position the inlet is closed and the outlet and the drain port are placed in fluid communication to drain the water system when the valve is shifted automatically under the influence of biasing means in reaction to low temperature sensing.