Abstract:
A joint suitable for construction castings having a frame and a lid or cover, such as manholes, grates, trench drains, hatches and the like, and construction castings incorporating the same. No tools are necessary to separate the joint. An enlarged head located on a cover fits into a socket located on a frame or adjacent lid. To separate the head from the socket, the lid is lifted to a substantially vertical position and turned about ninety degrees. The lid can then be lifted away from the socket. When the joint is used in manhole or hatch assemblies, a latch may be used to hold the cover open and the cover may be opened and closed with a lever.

Description:
CROSS-REFERENCE TO RELATED APPLICATION 
   This is a continuation-in-part of U.S. patent application Ser. No. 10/837,958 filed May 3, 2004. 

   STATEMENT CONCERNING FEDERALLY SPONSORED RESEARCH OR DEVELOPMENT 
   Not applicable. 
   FIELD OF THE INVENTION 
   This invention relates generally to construction castings, and more particularly to manhole, grate, catch basin, trench drain and hatch assemblies for covering openings and access points (hereinafter “covers”). 
   BACKGROUND OF THE INVENTION 
   Typically, manholes and other types of hatches must be covered either fully or partially (as with a grate) because they are needed in places where they are crossed over by pedestrians, cars, trucks, and even aircraft. Some of these manholes and hatches have hinged covers that can be conveniently opened and closed. Unlike non-hinged covers, hinged covers cannot become partially unseated as can happen with a sewer surcharge. Hinged covers may also be opened more easily than non-hinged covers. 
   One type of hinged cover is shown in Defrance et al., U.S. Pat. No. 4,840,514. Defrance discloses a manhole assembly having a lid that is hinged to a frame with a T-shaped lug. There are two principal disadvantages to this particular construction. First, in order to remove or replace the cover itself, something that is periodically necessary, an operator has to be able to lift the cover straight up to release it from the position in which it is held open. Given the weight and size of most such covers, this is a particularly difficult task. Second, these hinged covers cannot be lifted with ordinary levers thus requiring the application of brute force. 
   Another type of hinged cover is shown in a European Patent Office publication for Saint-Gobain PAM, EP 1160382. This hinged cover locks by dropping a lug down into a hinge receptor, requiring one to lift the cover before it can be lowered. This causes the user to lift the weight of the cover each time it is used, even when the cover is not removed from the frame. 
   Like manhole and hatch assemblies, trench drain grates and solid covers are used in places where they are crossed over by pedestrians, cars, trucks, and even aircraft, and are not easily accessed. Trench drain and grate covers fit into a frame that typically spans the width of a driveway or other area where drainage or ventilation is desirable. Frequently, it is necessary to fasten these grates and covers to the frames. In usual applications, each separate cover is bolted to the frame with a number of bolts—typically one in each corner or otherwise fastened with one of many types of an internal mechanical locking device. If one desires access to the trench or drain below the cover, each bolt must be removed or the mechanical locking device released so the cover can be lifted and removed. Lid removal is time consuming and sometimes difficult due to damaged bolts, broken mechanical locking devices or dirt. In addition, bolt patterns and mechanical lifting devices may change due to wear, and it may be difficult to replace the removed lids if they do not have the same orientation as they did prior to removal. 
   Accordingly, there is a well established need for a connector used in conjunction with various construction castings that is simple and easy to use and maintain. Because construction castings are typically heavy, there is a further need for construction castings that are more ergonomic for lid or cover opening and removal. 
   SUMMARY OF THE INVENTION 
   The present invention overcomes many of the drawbacks and disadvantages of the prior art. It includes a hinge construction that is simple and easy to manufacture. Moreover, covers made in accordance with the present invention can be lifted with a lever, thus greatly reducing the amount of lifting force required to open the cover. As a result of the hinge design of the present invention, covers can be readily removed from the hinge receptor, facilitating easy removal and replacement, without the use of tools. 
   The joint is used in a construction casting assembly. This joint may have certain features that limit the movement of a cover with respect to a frame. In another aspect of the invention, the joint is used to connect grates or trench-type drains in series. Generally, the grates are connected end-to-end and use relatively few bolts to lock the grates to a frame. In yet another aspect of the invention, the joint is used again to connect grates or trenches to a frame. Rather than linking each cover or grate together, each grate is instead independently connected to the frame. For example, a ball head extends from each grate that, in turn, fits into a corresponding socket of the frame. 
   Various other features, objects, and advantages of the invention will be made apparent to those skilled in the art from the following detailed description including illustrative examples setting forth how to make and use the invention. 

   
     BRIEF DESCRIPTION OF THE DRAWINGS 
       FIG. 1  is a perspective view of a manhole frame and cover connected with a ball and socket joint of the present invention; 
       FIG. 1   a  is a perspective view of the manhole cover of  FIG. 1 , the cover shown separately from the frame; 
       FIG. 1   b  is a perspective view of the manhole frame of  FIG. 1 , the frame shown separately from the cover; 
       FIG. 1   c  is a perspective view of the latch shown in  FIG. 1 ; 
       FIG. 2  is the manhole frame and cover of  FIG. 1 , with the cover locked in an open position; 
       FIG. 3  is a side elevational view of the manhole frame and cover and hold open safety device of  FIG. 2 ; 
       FIG. 4  is a partial cross-sectional view of the socket located in the manhole frame of  FIG. 2 , taken at line  4 — 4 ; 
       FIG. 5  is a partial cross-sectional view showing how a ball extending from the manhole cover fits within the socket shown in  FIG. 4 ; 
       FIG. 6  is a perspective view of the manhole cover and frame of  FIG. 2 , with the cover turned 90 degrees; 
       FIG. 7  is a perspective view of a pair of grate covers with the ball and socket joint of the present invention, the covers joined in series and the frame partially cut away; 
       FIG. 8  is a perspective view of the grate covers of  FIG. 8  showing a cover in a raised position; 
       FIG. 9  is a perspective view of the grate covers of  FIG. 9 , showing the raised cover of  FIG. 8  turned so that it may be detached from another cover; 
       FIG. 10  is a perspective view of the cover of  FIG. 8  being separated from another cover; 
       FIG. 11  is a top plan view of a series of end to end grate covers using another embodiment of the invention, wherein each grate cover is connected to a frame; 
       FIG. 12  is a view like  FIG. 7  of trench grates but showing the heads with bosses and fins and corresponding sockets; 
       FIG. 13  is a view like  FIG. 8  but of the trench grates of  FIG. 12 , with one of the grates hinged up 90 degrees about a horizontal axis; 
       FIG. 14  is a view like  FIG. 13  showing the hinged up cover turned by 90 degrees about a vertical axis; 
       FIG. 15  is a view of the raised and turned cover lifted out of the socket of the other cover; 
       FIG. 16  is a view like  FIG. 11  of trench grates with heads each having bosses and a fin and corresponding sockets in the frame; 
       FIG. 17  is a view like  FIG. 16  illustrating another embodiment of end to end trench grate covers supported by a frame made up of frame sections; 
       FIG. 18  is a detail view of sections of the cover assembly of  FIG. 17 ; 
       FIG. 19  is a partial cross-sectional view from the plane of the line  19 — 19  of  FIG. 18 ; 
       FIG. 20  is a view like  FIG. 19  but with the cover open; 
       FIG. 20A  is a detail view of the area  20 A— 20 A of  FIG. 20 ; 
       FIG. 21  is a top perspective view of a different embodiment of a trench grate cover by itself; 
       FIG. 22  is an end view from the plane of the line  22 — 22  of  FIG. 21 ; 
       FIG. 23  is a cross-sectional view of the socket portion of the frame; 
       FIG. 24  is a detail cross-sctional view of the area  24 — 24  of  FIG. 19 ; 
       FIG. 25  is a view like  FIG. 24  but showing the cover open; 
       FIG. 26  is a view of a single trench grate assembly; and 
       FIG. 27  is a cross-sectional view from the plane of the line  27 — 27  of  FIG. 26 . 
   

   DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT 
   Referring  FIGS. 1–1   b , the present invention comprises a relatively simple hinge, cover and frame assembly  10 . As can be seen, a cover  12  is connected to a frame  14  by a hinge subassembly or “joint”  16 , such that cover  12  is seated in frame  14  when the cover  12  is in a closed position. As shown in  FIG. 5 , joint  16  is generally constructed in a ball and socket arrangement. Depending upon the particular type of cover and frame, and the degree of security necessary in the connection of the cover to the frame, different embodiments of joint  16  may be employed. Preferably, joint  16  is constructed so as to permit removal of a cover  12  from a frame  14  without tools. As will be described more fully herein, such removal may be accomplished by merely opening the cover  12  to its open position, turing it 90 degrees, and lifting it out. Each action is performed separately and can be done manually or with a lifting device, if desired. 
   Referring to  FIGS. 1   a  and  5 , joint  16  has a first piece that includes a ball-shaped head  18  that is preferably connected to another structure such as cover  12 . Generally, the ball-shaped head  18  will be connected to cover  12  (or other cover as described herein) via a neck portion  20  or the like. As seen in  FIGS. 1   b  and  4 , head  18  fits into a socket  22  that is generally defined by a wall or surface  23  shaped to conform around the head  18 . Other features may be added to joint  16  to enhance its functionality. 
   One such feature, present in one preferred embodiment of the invention, is the modification of head  18  in a shape that is not a perfect sphere. Instead, the head  18  has a pair of parallel, flat, planar faces  24  positioned in symmetric, spaced apart relation to one another. In other embodiments of the present invention, the faces  24  may have concave and/or embossed surfaces. In these embodiments, a collar  26  is positioned above socket  22  and is constructed to correspond to the faces  24 . As shown in  FIG. 1 , where the head is constructed with the pair of flat faces  24 , the collar is  26  preferably defined by a pair of straight portions  30  connected by an arc-shaped portion  32 . The collar  26  has an open end located opposite arc shaped portion  32  to accommodate neck portion  20  when the cover  12  is in a closed position. Collar straight portions  30  are parallel and spaced apart at a distance in excess of the distance between the two flat faces  24 . When head  18  is oriented so that faces  24  are substantially parallel with the inside edges of straight portions  30 , head  18  fits between the straight portions  30  so that the head  18  can be inserted into socket  22 . As can be seen in  FIG. 6 , when head  18  is fit between straight portions  30 , cover  12  is sideways such that it cannot be lowered so as to achieve a closed position on frame  14 . As seen in  FIG. 2 , when cover  12  is rotated through 90 degrees so that the cover is in its normal open position, head  18  is also rotated such that flat faces  24  are perpendicular to straight portions  30 . In this position, cover  12  cannot be removed from frame  14  because collar  26  restrains the head  18 . Removal is not possible since the width of the head  18  in this position is wider than the space between the two collar straight portions  30 . Thus, faces  24  and collar  26  operate to prevent the accidental release of head  18  from socket  22 . 
   A second feature that may be incorporated in joint  16  is one or more bosses. See  FIG. 5 . In a preferred embodiment of the invention, a pair of cylindrical bosses  36  are positioned symmetrically on a common rotational axis that is centrally located between faces  24 . When present, the bosses  36  fit into a groove  38  that runs horizontally below the top of the collar  26 . Referring to  FIG. 4 , groove  38  bisects socket  22 , and has a depth and height so that it can slidingly accommodate bosses  36 . Thus, the cooperation between the bosses  36  and the groove  38  provide further resistance to the separation of the cover  12  from the frame  14  when the cover  12  is in its operational or deployed position. In order to permit the removal of cover  12  from the frame  14 , a vertical slot  40  that is centrally located on the collar arc  32  is provided. When the cover  12  is rotated 90 degrees to its removal position, one of the bosses  36  will fit to the slot  40 , such that the head  18  can be extracted from the collar  26 . When head  18  is inserted (or re-inserted) into the socket  22 , a boss  36  slides through slot  40  until it reaches groove  38 . At that point, head  18  can be twisted about the neck  20  axis so that bosses  36  slide within groove  38 . It should be noted that slot  40  can terminate at groove  38 , or extend below it. The slot&#39;s termination depends on the desired degree of lateral movement when the cover  12  is in its removal (or re-insertion) position or on the use of certain other features, as described below. Together, bosses  36  and groove  38  serve to restrict the movement of neck  20  (and any structure attached thereto). Within these restrictions, neck  20  may be twisted 360 degrees when oriented in a substantially vertical position, and neck  20  may rotate about bosses  36  when the bosses  36  are perpendicular to edges  30 . 
   A third feature that may be incorporated into joint  16  is a guiding fin  42 . Referring to  FIG. 5 , in accordance with another preferred embodiment of the present invention, fin  42  is a member that extends from the surface  44  of the head  18  directly opposite neck  20 . The purpose of fin  42  is to restrict the movement of the cover  12  when moving from a generally vertical (open) position (see  FIG. 3 ), to a horizontal (closed) position (see  FIG. 1 ), through a single plane of rotation. Without the fin  42 , the cover  12  could rotate during opening. Given the size and weight of the typical lid or grate used to cover manholes and the like, excessive rotation of the lid during opening could be dangerous and/or damaging. Preferably, the width of fin  42  matches the width of head  18  between the two faces  24  such that the two ends  46  of the fin  42  are flush with each of the faces  24 . Also preferably, the shape of fin  42  follows the overall spherical shape of head  18  such that the back edge  48  of the fin has an arcuate shape. The back edge  48  of fin  42  is dimensioned to fit in the portion of vertical slot  40  which is extended below groove  38 . In this embodiment, when the cover  12  is raised or lowered, the fin  42  moves within slot  40 . 
   Most preferably, the assembly shown in  FIGS. 1–6  includes the three features described above, namely fin  42 , bosses  36 , faces  24  and their corresponding slots and grooves. The frame  14  and cover  12  of assembly  10  need not be round or solid. Frame  14  and cover  12  may be rectangular (such as a hatch), slotted (such as a grate) or any other shape that fits the particular application for which a hinged cover is appropriate. In the preferred embodiment of assembly  10 , frame  14  has an external annular flange  50  from which rises a substantially cylindrical wall  52 . It should be noted that external annular flange  50  can be located anywhere on wall  52 , including around the top of the wall  52 , depending upon the application for which the assembly is intended. An inner flange  54  extends from the inner surface  56  of wall  52 . Flange  54  provides a surface on which cover  12  rests when cover  12  is in a closed position. 
   In the preferred embodiment of assembly  10 , joint  16  fits substantially within a housing station  60  that extends outwardly from wall  52 . Socket  22  is formed and resides within the housing station  60  such that its receipt of head  18  maintains the cover  12  in a substantially horizontal position as it rests, in its closed position, on inner flange  54 . 
   In another preferred embodiment of assembly  10 , a cover latch  62  is included. The purpose of latch  62  is to selectively lock cover  12  in an open position. Latch  62  operates in such a way that the operator need not substantially lift the cover  12  to a more open position in order to close it. As best seen in  FIG. 1   c , latch  62  may be made from a metal bar having a main body  64 . Referring to  FIGS. 2 and 3 , the proximal end of body  64  is pivotally fastened to cover  12  with a hinge assembly  66 . The body  64  has a distal end  68  that selectively contacts the flange  54  when cover  12  is fully open. Preferably, distal end  68  has a bottom surface  69  that is configured to rest squarely on flange  54 . This can be accomplished by angling the lower portion of body  64  resulting in a bottom surface that is at about 90 degrees to the angled lower body or by angling the bottom surface itself at an appropriate obtuse angle relative to the body  64 . Optionally, a boss  71  may be located on surface  69  adjacent the outermost edge of body  64 . Boss  71  overhangs the frame flange  54 . In addition, latch  62  may have an aperture  67  that extends through body  64 . To close cover  12 , aperture  67  may be hooked by a device that pulls the latch away from flange  54 . 
   When cover  12  is in a closed position as shown in  FIG. 1 , and the assembly  10  is intended for use as a manhole cover in a street or other thoroughfare, it is preferred to have the top surface  70  of cover  12 , the ball-head face  24 , and the top surface  72  of housing station  60  in substantially flush relation. This makes travel over the manhole assembly much smoother than if these components were not flush. Of course, it is common practice to emboss any top surface of a construction casting such as manhole assembly  10  to denote source of manufacturer, denote location of manhole, or to provide aesthetic value and/or a safety feature. 
   In operation, assembly  10  can be easily assembled and disassembled. After frame  14  is placed into a roadway or other structure, cover  12  is oriented in a position approximately 90 degrees from its normal open position as shown in  FIG. 6 . Head  18  is then aligned between straight portions  30  and inserted into socket  22 . Once in place, the cover  12  is rotated approximately 90 degrees to its normal open position. In the open position, if present, latch  62  can be used to maintain the cover  12  in place. The cover  12  is closed by disengaging latch  62  and seating cover  12  within the frame  14  on inner flange  54 . To remove cover  12 , the process is reversed. 
   Referring to  FIGS. 7–16 , in another embodiment of the present invention, a ball and socket joint  16  may be used in connection with a series of covers in the form of grates covering trench drain or the like. The grates  80  used to cover an elongated drain or opening are aligned in series and seated into a frame  82 . Generally, each grate  80  connects end-to-end as shown in  FIGS. 7–10  and  12 – 15 . Alternatively, the grates  80  could connect to the frame  82 , as shown in  FIGS. 11 and 16 . 
   As seen in  FIGS. 7–10  and  12 – 15 , each grate  80  has a socket  84  in a first end and a ball head  86  at the opposite end that is connected to the grate  80  via neck portion  88 . Specifically, grate  80  may be an elongated rectangular shape as shown. Preferably, a socket  84  is located centrally at one end of each grate  80 . The socket does not have to be centered, but the central location of socket  84  makes assembly easier. As seen in  FIGS. 8 and 13 , socket  84  is defined, at least in part, by a U-shaped notch  90 . Preferably U-shaped notch  90  includes a depression  92  that it conforms to the mostly spherical shape of ball head  86 . Located on the opposite end of grate  80  is head  86 . Like socket  84 , head  86  is preferably aligned with the longitudinal axis of grate  80 . As with prior embodiments, head  86  has a pair of opposite faces  93 . Faces  93  preferably lie in the same plane as grate surface  94  so that pedestrians and vehicles will experience a relatively smooth surface. However, as in other embodiments, faces  93  may be embossed or the like. 
   Also as with prior embodiments, head  86  can include a pair of cylindrical bosses  104  that are positioned symmetrically on a common rotational axis that is centrally located between faces  93 . When present, the bosses  104  fit into a groove  106  in the notch  90  of socket  84 . Groove  106  bisects socket  84 , and has a depth and height so that it can slidingly accommodate bosses  104 . The cooperation between the bosses  104  and the groove  106  thus provides further resistance to the separation of the grates  80 . Vertical slot  108  allows for the removal of one grate  80  from another grate  80 . Like in other embodiments, when one grate  80  is rotated 90° to its removal position, one of the bosses  104  will fit to the slot  108 , such that the head  86  can be extracted from the socket  84 . As well, when head  86  is inserted (or re-inserted) into the socket  84 , a boss  104  slides through slot  108  until it reaches groove  106 . At that point, head  86  can be twisted about the neck  88  axis so that bosses  104  slide within groove  106 . Bosses  104  and groove  106  thus together restrict the movement of neck  88  (and any structure attached thereto), as described above for other embodiments. 
   Also as previously described, joint  16  can also include a guiding fin  112 . Fin  112  is a member that extends from the head  18  directly opposite neck  88 . The purpose of fin  112  is to restrict the movement of the grate  80  when moving from a generally vertical (open) position (see  FIGS. 8 and 13 ), to a horizontal (closed) position (see  FIGS. 7 and 12 ), through a single plane of rotation. Without the fin  112 , the grate  80  could rotate during opening, which, as noted above, could be dangerous and/or damaging given the weight of the typical grate. The width of fin  112 , as in other embodiments, preferably matches the width of head  86  between the two faces  93  such that the ends of the fin  112  are flush with each of the faces  93 . As well, the shape of fin  112  preferably follows the overall spherical shape of head  86  such that the back edge  114  of the fin  112  has an arcuate shape, and the back edge  114  of fin  112  is dimensioned to fit in the portion of vertical slot  108  which is extended below groove  106 . When using fin  112 , when the grate  80  is raised or lowered, the fin  112  moves within slot  108 . 
   The frame  82  is generally an elongated rectangular frame into which a series of grates  80  may be fitted. The last grate  80  to be placed in the series may be bolted to frame  82 , such as shown in  FIG. 7  at corners  96 . Further, on the last grate  80 , the socket  84  may be omitted if desired. The first grate  80  of a series may also be bolted to frame  82  at its two outermost corners. Alternatively, the frame may have a head  86  or socket  84  located at one end so that the first grate  80  of a series may be connected to the frame  82  by the joint of the present invention rather than a pair of bolts. In addition, a pair of centrally located grates may be bolted down on abutting edges rather than be joined by a joint of the present invention. Alternatively, a central grate could be used as one of the grates between the end grates that had sockets in both ends, to end up with socket ends of the grates at both ends of the trench, at which ends the sockets may be omitted if desired. 
   In use, a first grate  80  is fit into frame  82 . Consecutive grates  80  may be linked to the first until the frame is completely covered by grates  80 . Preferably, the first and last grates  80  are bolted to frame  82  at their outermost corners. Removal of the grates  80  from frame  82  is demonstrated in  FIGS. 8–10  and  13 – 15 . In  FIGS. 8 and 13 , a grate  80  is lifted from a horizontal (closed) position to a vertical upright (open) position. In  FIGS. 9 and 14 , the upright grate  80  is twisted 90 degrees. In  FIGS. 10 and 15 , the upright grate  80  can be removed by pulling it straight upward. This is repeated until the desired number of grates have been removed. As in the prior embodiment, the head  86  cannot be removed from frame  82  until the head faces  93  are parallel to the opposite edges  94  of socket  84 . 
   In yet another embodiment of the present invention, shown in  FIGS. 11 and 16 , the configuration of sockets and heads are identical to sockets  84  and heads  86  in the previous embodiment. However, in this embodiment, the location of the sockets and heads is different. Rather than connecting the grates  80  in series, each grate  80   a  is independently connected to frame  82   a . Preferably, a socket  84   a  is located in frame  82   a , and a corresponding head  86   a  is located on each grate  80   a . Any grate  80   a  may be independently inserted and removed from frame  82   a  in a manner similar to that of the previous two embodiments. The grate may also be fastened to frame  82   a  so that it cannot be accidentally removed. For example, the side of grate  80   a  located opposite of head  86   a  may be fastened with a bolt or bolts  102 . 
   The grates  80 ,  80   a  and  80   b  are shown in  FIGS. 7–11  with a series of drainage outlets  100 . However, such grates could have a solid surface or differently configured outlets  100 . In addition, there are only two or four grates  80  shown in  FIGS. 7–11 . Any number of grates may be lined up in series. 
   In the embodiment  210  of  FIGS. 17–25 , the arrangement of  FIGS. 11 and 16  is used in which the necks  212  and enlarged heads  214  of the hinge joint extend from the sides of the grates  220  and are received in sockets  218  in the frame  224 . In this embodiment, the frame  224  is made up of frame sections  226  which may or may not be bolted together by bolts  230 . The construction of the enlarged heads, necks and sockets may be as described above, having bosses  232 , fins  234  and the socket shapes that conform to the bosses  232  and fins  234 . In addition, a latch  240  may be provided on each cover, so the whole trench can be opened and held open. As illustrated in  FIG. 21 , each cover may be provided with a handle or lifting recess  244 , in which a lever or pry bar may be inserted to assist in opening the cover and closing it. 
     FIGS. 26 and 27  illustrate a cover  220  like in  FIGS. 17–25 , but by itself in an individual frame  240 . 
   While the invention has been described with reference to preferred embodiments, those skilled in the art will appreciate that certain substitutions, alterations, and omissions may be made without departing from the spirit of the invention. Accordingly, the foregoing description is meant to be exemplary only and should not limit the scope of the invention set forth in the following claims.