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CROSS REFERENCE TO RELATED APPLICATIONS  
       [0001]     This application is a continuation-in-part of U.S. Ser. No. 11/335,591, entitled Storm Drain Basis Gate System, soon to be issued U.S. Pat. No. 7,234,894, issue date Jun. 26, 2007. 
     
    
     BACKGROUND OF THE INVENTION  
       [0002]     This invention relates generally to a gate system for use with a storm drain of the type typically found in the curb of a street. More particularly, this invention relates to such a system which during periods of low water flow is in a closed position to effectively prevent debris from entering into the storm drain, but which during periods of high water flow opens to allow the maximum amount of water to enter into the drain to alleviate the accumulation of water in the street and the surrounding areas.  
         [0003]     What to do with excess runoff rain water has been an issue for urban planners and dwellers for a long time. Even in arid regions, the occasional heavy rainfall will create large volumes of run off that must be channeled effectively or flooding resulting in impassable roads at least or the loss of property and lives at worst may occur. In areas of high annual rainfall, effectively channeling that rainwater away from streets and homes is an absolute must.  
         [0004]     For this reason, almost every city in the civilized world has an extensive underground storm drain system. And the most common inlet to the entire system is the ubiquitous curbside opening that is built into the sidewalk curb along the street. Those openings typically lead to a rather large underground chamber, often called a vault, at one end of which there is a conduit that leads to the main storm drain pipe that is usually set under the paved road adjacent the vault.  
         [0005]     These drain systems have proven very effective in channeling runoff storm water away from the streets and populated areas, and usually into an adjacent river or into the ocean. However, another ubiquitous part of urban life—street debris and litter—also finds its way into the storm drain system. For example, some cigarette smokers seem to believe that their cigarette butts are not litter to be deposited in a trash can, but something that can be thrown on the ground wherever they happen to be when they must discard the cigarette—thrown into the gutter as they walk along the sidewalk, or thrown out of the car as they drive along. These cigarette butts, which are not environmentally friendly and do not naturally degrade easily, invariably end up in the drain system and then into the river or ocean into which it drains. Other trash, from paper cups to hamburger wrappers to envelops, all find their way into the gutters, drain systems and ultimately river and ocean. And this is just the man-made debris. Naturally debris such as leaves and twigs are also commonly found in streets and gutters, and then make their way into the storm drain system when it rains, or when water from some other source makes its way into the street.  
         [0006]     It is not just the introduction of these items into the drain system that is a problem. Most storm drain systems ultimately empty directly into a nearly body of water, often a river or the ocean. Also, the systems rarely include any type of intermediate water treatment facility, so what goes into the drain system usually ends up in river, lake or ocean, where it is unsightly and can be toxic.  
         [0007]     Because the introduction of trash and other debris into the storm drain system is such a common occurrence, many street side drains are constructed with a sizeable open chamber into which the storm drain opening leads, with the conduit to the under-street pipe located at one end thereof. The purpose of this is to try to trap as much of the debris as possible in the vault, and only allow the water to run-off into the system. This has proven only partially effective. First, so much trash is often introduced into the vault that much of it gets into the system anyway. This is particularly true if there is an accumulation of trash in the vault when there is a heavy rainfall or other heavy flow of water into the vault. Second, this arrangement necessarily requires that the vault be periodically cleaned, and cleaning the vault cannot of course be done by the usual street sweeping equipment, but requires an entirely different piece of equipment with strong suction capability to literally vacuum the trash from the vault. Third, this arrangement is designed to allow the trash to accumulate in the vault in between cleanings, such that in a worst case scenario, the accumulated trash becomes so large that the drain becomes plugged wholly or partially, and flooding in the area occurs when it rains.  
         [0008]     In light of these issues, various attempts have been made to prevent trash from getting into drain. For example, in some places, a sizeable plate has been securely attached over the drain opening, leaving only a little space for water to flow. This solution does prevent much of the trash from entering into the drain, but it also prevents much of the water as well, and essentially defeats the purpose of the large drain opening that was intended to prevent flooding during heavy water run off. Therefore, other attempts have been made to design a storm drain gate that would remain closed during periods of low water run off, but which would automatically open in periods of heavy water run off. One recent example is U.S. Pat. No. 6,972,088, to Yehuda, in which a Pivotal Gate For A Catch Basin Of A Storm Drain System is disclosed. That system uses a rather complex system involving a rotatable paddle wheel and interconnected wires that interplay to open the gate when sufficient water begins to flow into the drain. While it appears workable, this system may not be desirable for widespread installation given its complexity, which translates into higher initial cost and higher cost of upkeep. It is a given in any piece of machinery that the more moving and complex the component parts, the more costly to manufacture and install, and the more costly to maintain, and more likely to malfunction. Other prior art devices suffer from one or more of these drawbacks, as the design goals of simplicity, ease of installation, durability, low maintenance, and high effectiveness are difficult to achieve.  
         [0009]     Therefore, there exists a need in the art for such a simple, effective gate system.  
       SUMMARY OF THE INVENTION  
       [0010]     The invention herein depicted and describes provides such a device wherein the gate portion of the system that prevents trash from entering into the vault or drain basin is kept in the closed position by virtue of a trip plate that is rotatably attached to the back of the gate. The trip plate is attached to back lower portion of the gate, and is biased (in the preferred embodiment by a spring) to an “up” position (that is, substantially perpendicular in the preferred embodiment) relative to the gate. The trip plate is prevented from moving backward (that is, away from the gate), which in the preferred embodiment is accomplished by two pins extending from the plate into a groove formed in each of a pair of brackets that are attached to the drain basin wall. Thus, when there is no-flow or low-flow of water through the gate onto the trip plate, the plate stays in position and in turn keeps the gate in a close position, flush against the drain basin opening. When the flow of water increases to a predetermined point, however, the water weight on the trip plate increases to the point where the upward biasing is overcome, and the trip plate rotates downward. This releases the gate and allows it to open. When the water flow onto the trip plate stops or reduces to a sufficiently low flow, the water weight on the trip plate is no longer sufficient to overcome the upward biasing on the plate, and it rotates back into its “up” position, which in turn causes the gate to rotate downward into its “closed” position against the drain basis opening. Also disclosed and claimed are improved and alternative apparatus for attaching the system to the storm drain basin, and for holding controlling the location of the trip plate.  
         [0011]     The preferred embodiments of this invention will now be depicted and described. As will be apparent to those skilled in the art, however, there are many different ways of attaching the various components of this system to the basin, and to one another, and of creating the biasing of the trip plate, and there are too many different ways to do so to list and describe here. Such common variants, even if not specifically described, are nonetheless considered to be within the scope of this invention. 
     
    
     DESCRIPTION OF THE FIGURES  
       [0012]      FIG. 1  is an exploded, perspective view of one embodiment of this invention.  
         [0013]      FIG. 2  is a partial side view of the preferred embodiment of this invention, showing the interplay between the gate, the trip plate and the guide brackets.  
         [0014]      FIG. 3  is a perspective view showing the gate system in its closed position within the opening of a curb drain basin.  
         [0015]      FIG. 4  is a perspective, exploded view, showing the component pieces of an alternative embodiment of this invention.  
         [0016]      FIG. 5  is a perspective, exploded view, showing in isolation one side of one embodiment of the invention.  
         [0017]      FIG. 6  is similar to  FIG. 5 , expect that the component pieces are shown assembled, with the exception that the lag bolt by which this bracket piece is attached to the drain basis is shown in exploded view. 
     
    
     DESCRIPTION OF THE PREFERRED EMBODIMENTS  
       [0018]     Looking at  FIG. 1 , it is seen that the preferred embodiment of this invention is for attachment to the inside of a curb-side storm drain basin  10 , adjacent to and providing a cover for the opening  12  that leads from the basin  10  to the street  14  through the curb  16 . It should be noted, however, that while the device of this invention is believed to find primary utility in this application, and is why the title of this invention includes a reference to a storm drain, the invention herein described and claimed is a gate system that is not limited to that one application. The device of this invention could be usefully applied to any situation where it is desired to screen particulate matter from a fluid flow through an aperture during no-flow and low-flow conditions, but to remove the screen from the aperture during high-flow conditions.  
         [0019]     The overall system consists primarily of a gate assembly  18 , the biased trip plate  20 , trip plate brackets  22 , and the various means by which these components are attached to one another, and to the side of the basin  10 . All components of this system are preferably constructed of  304  stainless steel. Other materials, however, could be used so long as they exhibited the required strength and durability appropriate for the application in which the system is used.  
         [0020]     Although  FIG. 1  shows in an exploded, perspective view how all of the various components are connected, the interplay of the gate assembly  18 , the biased trip plate  20  and the trip plate guide brackets  22  can best be seen in  FIG. 2 . The gate assembly  18  comprises in this embodiment a pair of gate plates  24  and  26  that are held together by any conventional means, in this instance by nuts and bolts  28 . Of course, there are a myriad of other ways to attach the two gate plates together, such as welding, gluing, screws, rivets, brackets, etc. Also, the gate assembly  18  does not have to be constructed of multiple plates, and could be of unitary construction, or could be of many individual plates.  
         [0021]     In this embodiment, the gate plate assembly  18  is rotatably attached to the basin  10  by means of a hollow tube  30  that is attached to the top of the gate assembly  18 , a pair of side pins  32  that are slidably housed within either end of the tube  30  and which are biased outwardly of the tube  30  by means of a spring  34  that is also housed within the tube  30  and forces the pins  32  outwardly. The distal end of the pins  32  engage appropriately-sized holes  33  in the large side brackets  36  and  38  (seen in  FIG. 1 , not shown in  FIG. 2 ), which are in turn attached to the side of the basin  10  by conventional means—in this instance, by bolts  40  that are set into appropriated-sized holes  42  the side wall of the basin  10  on either side of the opening  10 . As will be appreciated, this arrangement allows for easy attachment and free rotatability of the gate assembly  18  to the large side brackets  36  and  38 , as one of the pins  32  can be placed into one of the holes  33 , and then the other pin  32  can be pushed inwardly, the tube  30  brought into alignment with the other hole  33 , and that pin  32  then allowed to extend into that hole  33  so that the entire gate assembly  18  is now firmly yet rotatably attached into position against the opening  12 . As will be apparent, the attachment inter-relationship between these components can be adjusted to ensure that the gate  18  is properly positioned flushly against the opening  12 .  
         [0022]     To provide the desired screening function, the gate plates  24  and  26  have a number of holes  42  extending therethrough. These holes can be of any desired shape, size, configuration and distribution as desired under the circumstances. For example and not in way of limitation, commercial mesh screens could be used under the appropriate circumstances.  
         [0023]     Referring now back to  FIG. 2 , it will be seen that the trip plate  20  is rotatably attached to the lower end of the gate assembly  18 . Here, the attachment means provided are a pair of pins  44  attached to the side of the trip plate  20  and which communicate with appropriately sized holes  46  in small brackets  50  that are attached to the gate assembly  18  via the same nuts and bolts  28  that are used to attached gates plates  24  and  26  together. It will be appreciated, however, that the manner in which the trip plate  20  is attached to the gate assembly  18  is not limited to the means showed, and can be accomplished by any other conventional method and means whereby the trip plate  20  is securely but rotatably attached such that the trip plate  20  can rotate from a first or “up” position as shown in  FIG. 2 , downwardly to a second or “down” position, as shown in shadow in  FIG. 2 .  
         [0024]     Again looking at  FIG. 2 , the interaction between gate assembly  18 , the trip plate  20  and the side brackets  22  can best be appreciated. At the distal end of the trip plate  20 , a pair of outwardly extending pins  52  communicate with an arcuate groove  54  formed in each of the brackets  22 . In a no-flow or low-flow situation in which no or very little water is entering into the storm drain through the gate assembly  18 , the trip plate  20  is biased upwardly so that the pins  52  are pressed against the top of the grooves  54 . In this embodiment, the biasing of the trip plate  20  upwardly is accomplished by a pair of torsion springs  56  (seen only in  FIG. 1 ). One end of the torsion springs resides in hole  58  in the side bracket  50  and the other end of the torsion spring resides in the hole  60  in the trip plate  20 . Again, this is only one of many ways in which the trip plate  20  can be biased in an upward direction, and this invention is not limited to the one method and means shown.  
         [0025]     The side brackets  22 , the grooves  54  and the side pins  52  are all arranged such that in that position, the trip plate  20  extends in a horizontal fashion directly behind and perpendicular to the gate plates  24  and  26  on the gate assembly  18 . Thus, in this position, the interplay between pins  52  within the bracket grooves  54 , and the brackets  22  (which are attached to the side wall of the basin  10 ) has the effect of holding the gate assembly  18  in a vertical, “closed” position, flushly against the opening  12  in the drain basin  10 .  
         [0026]     The trip plate  20  will hold the gate assembly  18  in that position for so long as the water flowing through the basin opening  12  and onto the trip plate  20  is sufficiently small that the weight of the water bearing down on trip plate  20  is insufficient to overcome the upward biasing on the trip plate  20  caused by the torsion springs  56 . As the flow of water increases, however, and the resultant gravitational water weight acting on trip plate  20  increases, the upward biasing is overcome, and the trip plate  20  begins to rotate in a downward direction, shown by arrow  62 . As this occurs, the trip plate  20  moves out of its horizontal, perpendicular alignment relative to the gate assembly  18 , which in turn allows the gate assembly  18  to begin to rotate in an upward direction as shown by arrow  64 , effectively enlarging the open space to allow more water to flow into the basin. It will also be noted that as the trip plate  20  rotates downwardly, the side pins  52  travel downwardly within the grooves  54 . In one embodiment of this invention, the grooves  54  are provided with one or more detents  66  (only one of which is shown in  FIG. 2 ) which act as intermediately stopping points during the downward movement of the trip plate  20 . In other words, as the water flow onto the trip plate  20  increases and its starts to rotate downward, it will encounter one of the detents  66 . The pins  52  are forced into the detent, and will tend to reside there until the water weight increases incrementally until the pins  52  are forced out of the detents  66 . This will allow for staged opening of the gate assembly  18 , and will also work to prevent fluttering of the gate assembly as the water flow ebbs and increases. It will be appreciated that the size and depth of the detents  66  must be controlled so as to not unduly hinder the movement of the trip plate in either the downward or upward direction.  
         [0027]     As the water weight continues to increase, eventually the biasing and the detents are overcome, and the trip plate  20  will rotate entirely downward (as shown in shadow in  FIG. 2 ). At this point, the trip plate  20  ceases to exercise any limiting function on the gate assembly  18 , which in turn is allowed to rotate entirely open. By appropriate sizing and placement of the brackets  50 , the side pins  44  and the other components, the gate assembly  18  can be allowed to rotate through a full 90 degrees such that it comes to rest against the ceiling of the drain basis, in which case the storm drain opening  12  is complete unobstructed, maximum flow of water into the basis is allowed, and even trip plate  20  is pulled up substantially away from the water flow.  
         [0028]     Once the water flow recedes, the upward biasing on the trip plate  20  will again be greater than the water weight acting on the trip plate, and it will again rotate upwardly, simultaneously forcing the gate assembly  18  downward and into its closed position flush against the basin opening  12 .  
         [0029]     Referring back to  FIG. 1 , it will been seen that the trip plate brackets  22  are attached to the large side brackets  36  and  38  by nut and bolts  70  to provide added stability to the interplay between the trip plate pins  52  and the grooves  54 , the ends of the pins  52  can be fitted with washers  72  and screws  74  to ensure that the pins  52  remain within the grooves  54  at all times, even if the trip plate  20  happens to be subjected to an uneven, torquing force that might otherwise cause the pins to become dislodges from the grooves. Lastly, the overall system can include side plates  76  that are attached to the large side brackets  36  and  38  by conventional nut and bolts  78  and a simple flanged element  80  that is attached to the side bracket  38  by conventional nut and bolt  82 , and which acts as a “stop” to prevent the gate assembly  18  from being pulled open in the direction of the street.  
         [0030]     Referring now to  FIG. 3 , an alternative embodiment is shown. This embodiment can be utilized in a wide variety of drain basins where the curb-side openings are of different width. In this embodiment, there is a gate assembly  100  that has a gate  101  that comprises a frame  102  to which is attached a mesh material  104 . In this instance, the mesh material  104  is a section of metal grate commercially available that has apertures of the desired size and shape depending on the particulate matter to be kept from entering the basin when the gate section  100  is in the closed position (as is shown in the of the Figures). The mesh material  104  is attached to the frame  102  by any conventional means, such as by welding. The upper portion of the frame  102  is attached to rod  106 . As shown here, the frame  102  is welded to circular rod  106 , but any other attachment means could be utilized so long as the attachment is secure, fixed and durable.  
         [0031]     The rod  106  extends through a pair of appropriately sized apertures  108  and  110 , respectively, in bracket assemblies  112  and  114 . The size of apertures  108  and  110  should be only slightly larger than the diameter of rod  106  so that rod  106  can rotate, and slide side-to-side within the apertures, but is otherwise held generally in place. The overall length of rod  106  will be dictated by the overall width of the basin opening to be covered.  
         [0032]     The bracket assemblies  112  and  114  are designed and constructed to be attached to the horizontal portion  116  of the drain basin opening  12  (Compare to the brackets  36  and  38  above, which are designed to be attached to the vertical interior wall of the basin). The bracket assemblies  112  and  114  are preferably mirror images of one another, and, as best seen in  FIG. 5 , (the following description also applied to each) bracket assembly  112  has a base  118  to which a flange  120  is attached, and extends perpendicularly above the base  118 . In this preferred embodiment, flange  120  has an upper tab  122  that extends perpendicularly from the flange  120 . The tab  122  has a threaded orifice  124  into which a threaded bolt  126  is screwed. Bolt  126  is used to secure the bracket within the curb opening  12  as, once the bracket assembly  112  is properly position within the curb opening  12 , bolt  126  is screwed upward against the upper surface of the curb opening  12 , thereby creating a tension fit. Flange  120  also has a pair of horizontally elongated attachment slots  128 . The other main component of bracket assembly  112  is the adjustable guide  130 . Adjustable guide  130  has a series of vertically elongated slots  132 . Guide  130  is attached to flange  120  by conventional bolts  134 , washers  136 , lock washers  138 , and nuts  140 . The combination of the dual slots  128  and the multiple slots  132  allows for a large adjustment of the guide  130  to the flange  120 . As best seen in  FIG. 6 , the bracket assembly  112  is preferable secured within the curb opening  12  by means of a set bolt  142  that extends through hole  144  and engages an anchor (not shown) that has been set into the concrete of the basin opening.  
         [0033]     As best seen in  FIG. 6 , the rear (relative to the curb) portion of guide  130  is designed such that it has a rearwardly extending hook  150 . It will be noted that nose  152  the hook  150  extends downwardly a sufficient distance so that a pin (to be described below) will reside within the hook and will restrain the pin against for asserted against it in the rearward direction. Immediately below the nose  152 , the rearward edge  154  of guide  130  slants forwardly, toward the curb.  
         [0034]     Referring now to  FIG. 4 , the purpose of the guide  130 , nose  152  and rearward edge  154  will be described. As seen in this Figure, the gate assembly  100  includes a trip plate  160  that is attached to and extends from the rear portion of the gate  101  by means of hinges  162  and  164 . Hinges  162  and  164  are preferably attached to the lower corners of gate  101  by any conventional means, including welding, screws, or bolts, for example (not shown). Each of the hinges  162  and  164  have a hinge pin  166  and  168  that extend inwardly towards one another from the hinges  162  and  164 . The hinge pins  166  and  168  communicate with appropriately sized holes  170  and  172  on the side arms  174  and  176  on trip plate  160  such that when so engaged, the trip plate  160  is securely held within, but is rotatable with respect to, the hinges  162  and  164 , and hence to gate  101 . As will be understood by those skilled in the art, Circular springs  180  and  182  fits over hinge pins  166  and  168 , and the extending spring coil legs  184  and  186  fit into properly sized holes  188  and  190  that are formed in the trip plate arm  176  and hinge  164  respectively so as to bias the trip plate  160  into an upward orientation. As will be appreciated by those skilled in the art, the biasing force can be pre-determined by selecting the size and number of coils within the springs  180  and  182 .  
         [0035]     The remainder of this embodiment of the trip plate  160  comprises a central trough  192  that extends between the sides arms  174  and  176 . Also in this embodiment, the trip plate  160  has a pair of plates portions  194  and  196  that extend upwardly and rearwardly from the trough  192 . It will be noted that the trough  192  in this embodiment does not extend at the way to the from of the side arms  174  and  176 . Rather, there is a void area between the arms  174 / 176 , the trough  192  and the gate  101 .  
         [0036]     The trip plate  160  also has a pair of pins  200  and  202  that extend laterally from the rear portion of the side arms  174  and  176 . In this embodiment, each of the pins  180  and  182  are of two piece construction as shown. Various different constructions are of course possible. When the gate system  100  is fully assembled according to the attachment dotted lines in  FIG. 4 , it will be noted that when the trip plate  160  is in its upward position (as biased by the springs  180  and  182 , the pins  200 / 202  will be forced upwardly against hooks  150  in the two mirror image bracket assemblies  112 / 114 . The nose portions  152  of the hooks  150  are each sized and shaped relative to the size of pins  200 / 202  such that when the pins  200 / 202  are in position within the hooks  150 , the pins  200 / 202  cannot move in a rearward direction, such movement being retrained by the nose portions  152 . As will be appreciated, this interaction between the pins  200 / 202  and nose portions  152  will prevent the gate assembly  101  into place in the closed position against the drain basin opening. As a low flow of water comes through the mesh material  104  of gate assembly  101 , the natural tendency of moving water to adhere to an adjacent surface will cause the water entering the drain basin opening  12  mainly to flow into the void space in front of the trip plate  160 . As the water flow increases, however, some of the water will start to flow onto the trip plate  160  before cascading into the drain basis. As the water flow increases, the amount of water that is instantaneously acting against the trip plate  160  will also increase until the upward biasing force of the springs  180 / 182  is overcome. At that point, the rear portion trip plate  160  will start to move downwardly, rotating upon hinge pins  166 / 168 . Once the rear portion of trip plate  160  has moved downwardly a sufficient amount, then pins  200 / 202  are freed from hooks  150 . At that point, the pins  200 / 202  no longer act to hold the gate  101  in a closed position against the drain basin opening, and the pressure of water on gate  101  will swing it widely and immediately open. As it does, the gate  101  rotates on rod  106  into an open position against to top of the drain basin. Once the flow of water has receded, the gate  101  will drop back into place and the pines  200 / 202  will be brought back into position with the hooks  150 .  
         [0037]     As will be appreciated, the size and shape of the gate  101 , the mesh material  104 , the trip plate  160 , the nose  150 , and the strength of the biasing springs can be varied, so long as the resultant design works to open the gate  101  upon the desired flow of water. As will be appreciated, as the flow of water increase, more pressure is applied to the gate  101 , which applies more pressure by pins  200 / 202  against the nose portions  150 , so that will have to be taken into consideration. This is easily done by those skilled in the art. A representative embodiment is shown in  FIG. 4 , which is drawn generally to scale.  
         [0038]     The final aspect of this embodiment includes side panels  206  and  208 . These side panels  206 / 208  preferably have a similar frame and mesh material construction as gate  101 , and are sized and shaped so as to fully occupy the remainder of the basin opening  12  on either side of the gate  101  (as best seen in  FIG. 3 ). In this embodiment, the upper portion of the panels  206 / 208  are attached to a tubular member  210 / 212  which is sized and shaped so as to fit snugly onto rod  106 . Once in place within the complete system, it will be seen that the backside of panels  206 / 208  rest against flanges  120  and are thus held into the closed position. As will also be appreciated, where this overall system is to be installed on a number of drain basin openings of varying widths, this embodiment can be utilized with a standard gate system  100  of common size, but with the ability to easily change the size of only three components in the overall system (that being the length of rod  106 , and the width of side panels  206 / 208 ) in order to accommodate a wide variety of basin opening widths.  
         [0039]     Lastly, in order to provide some protection to the rod  106 , an L-bar  214  can be attached to the upper portion of the basin opening  12 .  
         [0040]     Although preferred embodiments have been shown and described, the disclosed invention and the protection afforded by this patent are not limited thereto, but are of the full scope of the following claims, and equivalents thereto.

Summary:
An automatically openable and closeable gate system that will find primary use with the street curb opening to a catch basin or vault of a storm drain system, and for other similar openings, the system having a gate which during dry and low-flow water drainage situations will be in a closed position such that items of trash, debris, litter, leaves and the like will be prevented from entering the basin, vault or system, yet in periods of heavy rainfall or other heavy water run-off situations will automatically open to allow free flow of water into the basis or vault to alleviate water accumulation in the adjacent street and other surrounding areas.