Abstract:
A locking device for a storm grate to prevent theft or vandalism by unauthorized individuals. The device typically includes an upper plate, a positioning frame, at least one coupler nut, and a bolt. The positioning frame can include the coupler nut, a catch end for engaging the frame of the grate, a lower plate for engaging the underside of the grate, and a pliers handle for holding the device during insertion through a drain opening. In one embodiment, a second coupler nut is part of a wing wedge that secures a lower plate of the positioning frame to the underside of the grate. A method of inserting the device includes lowering the device through an opening in the grate, securing the catch end around the frame beneath the ground, and then tightening the bolt.

Description:
FIELD OF THE INVENTION 
     The present invention relates generally to storm grates or other water drainage or catch basin grates located near the curbs of paved roads, and more particularly to locking devices for such grates to prevent their theft. 
     BACKGROUND OF THE INVENTION 
     Storm grates, or water drainage grates, are commonly located along paved roadways to transport surface water into underground storm drains, or to house utilities. Such grates are commonly constructed out of cast iron, and typically include parallel spaced bars in a grid pattern, with the openings between the bars suited for receiving surface water. The upper surface of the grate is typically level with the road surface (i.e. the pavement). 
     Storm grates are usually mounted on an associated frame which is embedded in the ground or in concrete pavement near the curb. An interior ledge or supporting shoulder of the associated frame supports the weight of the grate, which fits flush with the frame aperture, such that the grate can be readily removed if it becomes necessary to clean out the storm drain, or for some other purpose. Although storm grates can be very heavy, weighing up to one-hundred fifty pounds, they are quite often removed from their mounting frames by unauthorized persons as an act of theft or vandalism. The large opening left behind in the pavement represents a serious injury hazard to a person or a vehicle, and the stolen grates must be replaced, with consequent expense to the city. 
     Although lockable grate systems are known, standard heavy storm grates which are lowered into their mounting frames and thereafter not locked or secured in any manner are still commonly used in many municipalities. Therefore, there is a need to secure storm grates in place to prevent unauthorized removal and the subsequent hazards resulting from a stolen or unseated grate. 
     The prior art discloses various ways of securing storm grates. U.S. Pat. No. 7,201,533 to DeGreef discloses a locking mechanism for preventing removal of the grate from its mounting frame by unauthorized persons. The locking mechanism includes a grate hold-down device which overlaps and completely encircles one of the grate bars, a threaded nut attached to the mounting frame below the hold-down device, and a bolt extending downwardly through the hold-down device into threaded engagement with the nut. 
     U.S. Pat. No. 6,942,419 to Knak discloses a system grate assembly which includes a frame and a complimentary grate which is designed to be locked to the frame by a specific locking device which is located below the grate, and is inaccessible from the street level. 
     U.S. Pat. No. 5,340,232 to Spiess discloses a manhole cover interlocked with a complimentary mounting frame. The cover and frame are designed to function together, and include a securing device which allows the grating or cover to be fitted and removed easily. The securing device is not locked to the frame, and comprises a “spring-clip” type device rather than a lock. 
     U.S. Pat. No. 4,142,329 to Williams discloses a locking assembly for a grate having two subassemblies that can be added to existing installed storm grates to prevent loss of the grate through theft or vandalism. The first subassembly is secured to the grate by a pair of cross plates and a bolt. The second subassembly supports a horizontal movable locking member and a compression coil spring which keeps the locking member engaged with the grate frame. A removable pivotal lever is used to move the locking member against the force of the coiled spring, thereby permitting the grate to be removed by authorized personnel. 
     While such prior art grate locking devices and systems may be useful for their intended purposes, there remains a need for a storm grate security lock that can be fitted easily onto existing unsecured storm grates to prevent their theft and protect them from vandalism. It would therefore be advantageous to provide a locking device for an unsecured storm grate that can be installed without having to remove the storm grate, which provides strong locking capacity, and which utilizes an uncomplicated design that is easy to manufacture. 
     SUMMARY OF THE INVENTION 
     The present invention provides a security locking device that can be easily installed on such unsecured grates so they may be locked to their mounting frames, for deterring would-be thieves or vandals from removing the grate. 
     A first aspect of the invention provides a locking device for securing an existing installed storm grate to its associated mounting frame, the locking device comprising: (a) an upper plate for placing on the top of the grate; (b) a positioning frame, the positioning frame comprising: (i) a pliers handle for holding the frame with a pair of pliers during insertion; (ii) a coupler nut; and (iii) a catch end for engaging the underside of the mounting frame of the grate; and (c) a bolt for passing through aligned holes in the upper plate and the coupler nut and securing the locking device onto the grate and its frame, wherein the locking device can be fitted onto an existing installed storm grate and its associated frame and locked in place without having to remove the storm grate. 
     A second aspect of the invention provides a locking device for securing an existing installed storm grate to its associated mounting frame without having to remove the storm grate, the locking device comprising: (a) a bolt for securing the locking device onto the grate and its frame; (b) an upper plate for receiving the bolt therethrough; (c) a positioning frame, the positioning frame comprising: (i) a lower plate for receiving the bolt therethrough; (ii) a pliers handle; (iii) a vertical arm; (iv) an elbow; (v) a horizontal arm including a first coupler nut for receiving the bolt therethrough; and (vi) a catch end adapted to engage the underside of the mounting frame; and (d) a wing wedge for engaging the underside of the grate, the wing wedge including a second coupler nut for receiving the bolt therethrough and a stop for blocking rotation of the wing wedge, wherein the wing wedge is screwed onto the bolt via the second coupler nut and positioned on the bolt beneath the lower plate and above the first coupler nut, and wherein during insertion of the device the wing wedge is rotatable about the bolt until rotation is blocked by the stop, the stop causing the wing wedge to take a final position substantially perpendicular to the positioning frame. 
     A third aspect of the invention provides a method of installing a locking device for securing an existing installed storm grate to its associated mounting frame without having to remove the storm grate, the method comprising: (a) holding a locking device with a pair of pliers; (b) lowering the locking device through a drain opening in the grate; (c) positioning a catch end of the locking device to engage an underside portion of the mounting frame; and (d) tightening a bolt of the locking device to secure the locking device to the grate and its associated mounting frame. 
     The positioning frame of the device can have a vertical arm, an elbow, and a horizontal arm leading to the catch end, or it can be in the shape of an elongated J-bolt which advances both vertically and horizontally towards its catch end. The catch end of the device is adapted to either engage or wrap around an underside of the mounting frame for the grate. The bolt head is typically specially configured in a manner known in the prior art, requiring a specially constructed wrench to unscrew the bolt for removing the lock, and thus for removing the grate from its frame. Unauthorized persons are typically unable to obtain the specially constructed wrenches, which are only available to authorized sewer maintenance personnel for sewer clean-out or repair purposes. 
     These and further objects, features, advantages and characteristics of the locking device of the present invention will be more fully appreciated upon viewing the following drawings, detailed description of the preferred embodiments, and claims. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       The accompanying drawings illustrate embodiments of the invention and, together with a general description of the invention given above, and the detailed description given below, serve to explain the principles of the invention. 
         FIG. 1  is a perspective view of one embodiment of a locking device of the invention, having a wing wedge. 
         FIG. 2  is an exploded view of an embodiment similar to that of  FIG. 1 , but showing attachments for the catch end. 
         FIG. 3  is a perspective view of another embodiment of a locking device of the invention. 
         FIG. 4  is a partial perspective view of embodiments of the invention removably secured to a grate and its associated mounting frame. 
         FIG. 5  is a top perspective view showing embodiments of the invention securing a double grate. 
         FIG. 6  is a perspective view of another embodiment of the locking device of the invention. 
         FIG. 7  is a top perspective view showing the embodiment of  FIG. 6  securing a double grate. 
     
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
     The present invention is a locking device for existing, unsecured removable sewer/storm grates that can be installed without having to remove the storm grate from its associated mounting frame. 
       FIG. 1  illustrates one embodiment of the locking device of the present invention  10  (referred to as a “wing wedge” embodiment), which is adapted to lock a single storm grate to its associated mounting frame. The device  10  includes a positioning frame  18 , an upper plate  24  and a bolt  30 . The positioning frame  18  includes, at its proximal end, a lower plate  26  for receiving the bolt  30  therethrough, and pliers handle  28  for holding or gripping the device  10  during insertion. The frame  18  further includes a vertical arm  20 , an elbow portion  27 , a horizontal arm  22  with a first coupler nut  17  for receiving the bolt  30  therethrough, and a distal nose or “catch” end  25 , for catching or engaging the underside of the drain&#39;s mounting frame or a ledge portion thereof. The elbow  27  portion of the positioning frame  18  provides a physical transition from the vertical arm  20  to the horizontal arm  22 , so that the distal nose of the catch end  25  is able to engage any substantially horizontal underside of the grate&#39;s mounting frame. A wing wedge  16  also rotates about the bolt  30  and includes a second coupler nut  23  for receiving the bolt  30  therethrough. 
     As illustrated in  FIGS. 1 and 2 , the bolt  30  passes through and screws into aligned holes in the following order: the upper plate  24 , which serves as a washer for the bolt head  31  above the level of the grate, the lower plate  26 , the coupler nut  23  of the wedge  16 , and the coupler nut  17  of the positioning frame  18 . The bolt  30  and coupler nuts  17 ,  23  are typically threaded and adapted so that the bolt screws down and into threaded engagement with the coupler nuts. The bolt  30  typically includes a bolt head  31  that requires a special wrench to screw/unscrew the bolt, as is known in the art. 
       FIG. 2  is an exploded view of another wing wedge embodiment  11  similar to the embodiment  10  of  FIG. 1 . However, in this embodiment  11  the positioning frame  18  includes a series of modified catch ends  25   a ,  25   b ,  25   c  and  25   d  for engaging the underside ledges of atypical or different types of mounting frames. The modified catch ends  25   a - d  are attachments for a modified horizontal arm  22   a , which is substantially flat at its distal end but includes holes  53  for receiving attachment bolts  55 . Attachment bolts  55  are used to reversibly connect the different attachments  25   a - d , each of which also include pairs of holes  53  that can be aligned with those in the modified horizontal arm  22   a.    
     Specifically, attachment  25   a  of  FIG. 2  is intended for situations in which the depth of the underside ledge of the mounting frame is lower than a typical ledge. The downward turn of the attachment end can be specifically manufactured to fit the depth of a particular frame ledge. Attachment  25   b  is intended for use in situations in which the drain openings of the grate are not perpendicular to the frame (e.g. for diagonal drain openings). The slight bend of attachment  25   b  allows it to grip the underside of the frame, regardless of the angle of the drain openings to the frame. Attachment  25   c  is intended for use in situations where the walls of the mounting frame have no underside ledge, such that there is no place for the catch end of the positioning frame to engage the mounting frame. In such a situation, typically a ⅜″ hole can be drilled into the mounting frame or pavement, the hole to be used as a gripping point for the attachment. The horizontal arm  22   a  can be fitted with a drill head tip for the purpose of creating the hole. Attachment  25   d  is intended for use in situations where the underside ledge of the mounting frame is not substantially right-angular for engaging from below, so that the curved catch end can engage and grasp some portion of the underside of the frame. Other attachments can be specifically manufactured to fit a specific type of mounting frame ledge. 
       FIG. 3  illustrates another embodiment of the locking device of the invention  40  (referred to as the “J-hook” embodiment), and includes a positioning frame  42  substantially in the shape of an elongated letter “J”. This embodiment also includes a coupler nut  43 , an upper plate  44  and a bolt  50 . The positioning frame  42  includes a catch end  45  for engaging and securing the device around a large I-beam or to the underside of a deeply embedded mounting frame (see  FIG. 4 ), an elongated arm  46  that travels in both a vertical and a horizontal direction, an elbow  47  transitioning the elongated arm  46  to a catch end  45 , and pliers handle  48  at the proximal end. As illustrated, the coupler nut  43  is typically welded to the positioning frame  42  at the juncture between pliers handle  48  and the top portion of the elongated arm  46 . While the J-shaped positioning frame  42  is straight horizontal at this welding juncture, it can be appreciated by viewing  FIG. 3  that the positioning frame  42  gradually begins to travel in both a vertical and horizontal direction before reaching the elbow  47 . This is intended to allow the device to reach vertically below the level of the frame and also to engage its horizontal underside via the catch end  45 . 
     As shown in  FIG. 4 , the locking devices illustrated in  FIGS. 1 ,  2  and  3  can be removably secured to a standard storm grate  12  and its associated mounting frame  14  or I-beam  15 . Typical storm grates are rectangular in shape and have a series of bars connected in a grid pattern and spaced to form drain/grate openings (see  FIGS. 5 and 7 ). The grate can be a single grate, or two grates may be seated together side by side in a double grate configuration, as depicted in  FIGS. 4 ,  5  and  7 . The grate  12  is typically seated on an associated mounting frame  14  which is permanently integrated with the ground or pavement, and both are typically made of a heavy, one-piece cast iron construction. 
     The left half of  FIG. 4  illustrates a “wing wedge” embodiment  10  (or  11 ) of the locking device of the invention secured to the left underside edge  19  of the grate  12 . It can be appreciated that the positioning frame  18  is situated substantially beneath the level of the grate  12 , with the catch end  25  of the horizontal arm  22  engaging the underside ledge  19  of the mounting frame  14 , and the wing wedge  16  engaging the underside of the grate  12 . 
     During placement of the wing wedge device  10 , the wedge  16  is initially inserted parallel with the drain openings ( 56 , see  FIG. 5 ) so that it can fit through the storm grate  12  and into the space beneath the grate. As the bolt  30  is tightened, the wing wedge  16  rotates about the bolt  30  until the stop  36  blocks further rotation of the wedge  16 . At this point further rotation of the wedge  16  is blocked by the stop  36  in a position substantially perpendicular to the positioning frame  18 , as illustrated. The bolt is then further tightened and the wing wedge  16  is drawn upward towards the grate  12  and partially into the drain opening it was inserted through, until the slanted outside edges, or “wings” of the wing wedge  16  make contact with the underside of the grate  12 . After fully tightening the bolt, the wing wedge  16  is lodged against the underside of the grate  12 . The contact points of the wings of the wing wedge  16 , along with the contact points provided by the catch end  25  to the ledge  19  and the upper plate  24  with the top of the grate  12  (all of which are secured by the bolt  30 ), serves to fix the device  10  in place and secure the grate  12  to the grate frame  14 . 
       FIG. 4  also illustrates the “J-hook” embodiment  40  of the locking device inserted at the right underside edge of the grate  12 . The positioning frame  42  is gripped by the user via pliers handle  48  and lowered through one of the drain openings to a position substantially beneath the level of the grate  12 , with the catch end  45  passing completely underneath and around the mounting frame or I-beam  15  at the elbow  47 . The positioning frame  42  is then secured in place by tightening the bolt  50  as it passes through the upper plate  44 , which is placed on top of the grate  12 , and the coupler nut  43  of the positioning frame  42 , which is located below the grate  12 . The upper plate  44  and the coupler nut  43  have aligned holes to receive the bolt  50 . Contact points fix the device  40  in place and secure the grate  12  to the grate frame  14 , and include the contact between the elbow  47  portion of the catch end  45  to the I-beam  15 , and the upper plate  44  with the top of the grate  12 . The bolt is typically tightened via a special wrench engaged in the bolt head  51 , and the locking device  40  is secured to the grate  12  and frame  15  until an authorized individual uses the special wrench to loosen the bolt  50  and remove the locking device  40 . 
       FIG. 5  shows a standard heavy storm grate system and its associated mounting frame, as viewed from above. This particular grate includes a double grate configuration, with two grates  12 A,  12 B mounted side by side next to a roadside curb  13 , and a central I-beam portion  15  forming the center of the mounting frame  14  between the two grates. Here, both the “wing wedge” embodiment  10  (or  11 ) and “J-hook” embodiment  40  are used to secure each of the grates  12 A,  12 B. As illustrated, once the devices are inserted, only the upper plates  24 ,  44  and the bolt heads  31 ,  51  of the devices are exposed above the level of the grates  12 A,  12 B. The remaining portions of the devices are located either within a drain opening  56  or substantially beneath the level of the grates, after being inserted through one of the drain openings  56 . It can also be appreciated by viewing this figure that these devices  10 ,  40  can be inserted without having to remove the grate from its associated frame. 
     Looking at the wing wedge embodiments  10  of  FIG. 5 , it can be appreciated that the pliers handle  28  can be gripped by the user to lower the device through one of the drain openings  56  to a position beneath the level of the grate  12 . The device  10  is then secured in place by tightening the bolt head  31 . The wing wedge  16  is initially lowered beneath the grate in a direction parallel to the openings  56 , and then rotates about the bolt during tightening until it is stopped (by the stop  36 ) at a position substantially perpendicular to the drain openings. Once in this perpendicular position, further tightening of the bolt causes the slanted side walls of the wing wedge to make contact with the underside of the bars of the grate and so become lodged or otherwise secured to the underside of the grate  12 . 
     While the double grates  12 A and  12 B illustrated in  FIG. 5  show cross drain openings  56  that are perpendicular to one side and parallel to another side of the grates, a particular storm grate may have diagonal drain openings and still be securable by the locking device of the present invention. For example, as discussed and illustrated in  FIG. 2  above, the “wing wedge” embodiment of the device  10  can include an attachment  25   b  at its catch end that curves to reach the ledge of the grate frame. Further, the “J-hook” embodiment  40  can be modified to include a swivel (see  FIG. 6 ) which allows the positioning frame  46  to rotate about an axis and thus allow its catch end  45  to grip the underside of the frame, regardless of the angle of the drain openings to the frame. 
     As the name implies, the pliers handles  28 ,  48  are intended for holding the device with a pair of pliers as the positioning frame  18 ,  42  is lowered through one of the drain openings  56  of the grate. The catch end  25  of the “wing wedge” embodiment  10  of  FIG. 1  (or one of the catch end attachments  25   b - d  of the embodiment  11  of  FIG. 2 ) is then directed by the user to engage the ledge  19  of the mounting frame  14 . Similarly, the catch end  45  of the “J-hook” embodiment  40  of  FIG. 3  is directed by the user to hook around the mounting frame or I-beam  15  (see  FIG. 4 ). Once the frame or I-beam of the grate is engaged by the elbow  47  of the catch end  45 , then the bolt is tightened and the device is secured in place until removed by an authorized person. Placement of the majority of the device below the level of the grate assures that the only portion of the device exposed and thus accessible to the public above the level of the grate is the upper plate  24 ,  44  and the bolt head  31 ,  51  (See  FIG. 5 ). Typically, only authorized personnel will have the correct wrench needed to access the bolt head and loosen the locking device. 
     Another embodiment of the invention is illustrated in  FIG. 6 , which shows a locking device  60 , referred to as the “U-hook” embodiment, including an elongated positioning frame  62  substantially in the shape of the letter “U”. It can be appreciated that this U-hook embodiment  60  essentially incorporates two J-hooks (i.e. from  FIGS. 2 and 4 ) in a single mechanical element, such that a double storm grate can more easily and quickly be secured. The U-hook device  60  includes two coupler nuts  63 A,  63 B, and an elongated upper plate  64  that stretches all the way across the top of the central I-beam  15  (see  FIG. 7 ) and is secured by bolts  70 A,  70 B having heads  71 A,  71 B. The U-shaped positioning frame  62  includes a catch end  65  for engaging and securing the device around the large I-beam  19 . While the catch end  65  is generally flat for securing around large I-beams, it can be manufactured to have a central portion in the shape of a teardrop, as illustrated. This tear-drop shape allows the catch end  65  to hook around both a wide portion (typically about four inches wide) of an I-beam  19 , and also to envelope a narrow portion (typically about two inches wide) that are sometimes present, or to fit around oddly shaped I-beams. The two elongated arms  66 A,  66 B travel in both a vertical and a horizontal direction to join at the catch end  65 . This embodiment has at least one pliers handle  68 A for grasping the device with pliers during insertion through the drain openings as described above, but as illustrated here can also include a second pliers handle  68 B for allowing the user to grasp either and/or both ends of the device during insertion. 
     The embodiment of  FIG. 6  also illustrates a first swivel  72 A and a second swivel  72 B, each swivel  72 A,  72 B being located just below the first coupler nut  63 A and the second coupler nut  63 B, respectively. While each of the coupler nuts  63 A,  63 B are typically welded to the positioning frame  62  at the juncture between their respective pliers handles  68 A,  68 B and elongated arms  66 A,  66 B, the swivels  72 A,  72 B allow for rotation of the tips of the device (i.e. the pliers handles  68 A and  68 B) on an axis. This swiveling action is desirable for adjusting the device to fit at any angle necessary while fitting through the drain openings and/or securing the U-shaped catch end  65  around the I-beam  15 . While  FIG. 6  illustrates the swivel element for the U-hook embodiment  60 , one of skill in the art will understand and appreciate that the swivel element can also be used on the J-hook embodiment of  FIGS. 3 and 4 , and will be useful in rotating the securing the catch end  45  of the J-hook around an I-beam that is at an angle to the direction of the drain openings. Typically each swivel  72  can be in the form of a simple coupler nut that can turn the pliers handles  68  about an axis, but other swivel designs as are known in the art can be employed. 
     To secure the U-hook device  60  of  FIG. 6 , the entire device can first be grasped at the first pliers handle  68 A and inserted/lowered through a drain opening ( 56 , see  FIG. 7 ) on one side of the I-beam  15  (e.g. the left side), and the positioning frame  62  can then be maneuvered so that the second pliers handle  68 B, the second coupler nut  63 B, and the second elongated arm  66 B are threaded under and around the I-beam  15 . The distal end or, if included, the second pliers grip  68 B, is then directed upwards towards the drain opening of the second grate  12 B of the two grates, causing the catch end  65  to be seated directly beneath the I-beam, as illustrated. The swivels  72 A,  72 B can allow the tips of the device to then be rotated into a position that is optimal for securing the bolts  70 A,  70 B through their respective coupler nuts and the elongated upper plate  64 , so that the device  60  is secured across the I-beam  15  and to the two grates  12 A,  12 B. 
       FIG. 7  shows a top perspective view of the device  60  of  FIG. 6  secured a standard heavy storm grate having a double grate configuration and its associated mounting frame  14 . The grate includes two grates  12 A,  12 B mounted side by side and a central I-beam portion  15  forming the center of the mounting frame  14  between the two grates. As illustrated, once inserted, only the elongated upper plate  64  and the bolt heads  71 A,  71 B of the devices are exposed above the level of the grates  12 A,  12 B. The remaining portions of the devices are located either within a drain opening, such as the tips  68 A,  68 B, or substantially beneath the level of the grates. In  FIG. 7 , it can be appreciated that the elongated upper plate  64  can be a long, flat stock washer that holds both ends at the same time, allowing the connection of the flat stock washer to the two bolts  70 A,  70 B. 
     The locking device of the invention is typically made of a high strength corrosion-resistant material such as metal, and can include a coating which further protects the metal against corrosion. Such coatings can be a powder coating (paint powder applied in an oven to form a continuous film over the metal) or a trivalent chromate coating. Trivalent chromates produce a harder, scratch-resistant coating with lower water content providing more heat resistance. The bolt is preferably made of stainless steel, and is between about 3 inches and about 7 inches long, more preferably about 5 inches long, and between about ⅜ inches to about ½ inches in diameter, for ensuring a strong locking engagement with the frame. The height of the wing wedge embodiments  10 ,  11  is between about 3 inches and about 7 inches long, more preferably about 5 inches long as this is the typical depth of the underside ledge of a mounting frame, and the height of the J-hook and U-hook embodiments is between about 7 inches and about 15 inches long, but can be made longer or shorter, depending on the depth of the mounting frame or I-beam that the device must engage below. 
     While the present invention has been illustrated by the description of embodiments and examples thereof, it is not intended to restrict or in any way limit the scope of the appended claims to such detail. Additional advantages and modifications will be readily apparent to those skilled in the art. Accordingly, departures may be made from such details without departing from the scope or spirit of the invention.