Abstract:
The present invention provides an earth anchor to secure a cover over a trench or hole in the ground. The device has a retaining cap which is attached to a rod. Extendible arms are connected to the rod below the cap. The end of the rod opposite the cap is inserted into the hole or trench until the cap rests at ground level, either on separate cover plates or on the ground itself. For large holes, the cap retains separate cover plates over the hole; for small holes, the cap acts as a cover itself. The arms are extended by a jack screw, rack and pinion, or other means until they contact the substrate or underside of the cover plates and clamp the same between the cap and the arms. The cover can be removed by reversing the motion of the jack screw or rack and pinion, and retracting the arms, thereby freeing the device to be removed from the whole.

Description:
BACKGROUND OF INVENTION 
     This invention relates generally to an apparatus for removably securing structures to the ground. More specifically, this invention relates to an anchor for removably securing a cover over a trench or hole in the ground. 
     Access holes are dug in the street or right-of-way to access and locate underground utilities. If the hole must be left unfilled for continuing work the next day or for later inspection, the common practice is to place one or more heavy cover plates of 0.5″-1.25″ steel over the opening in the ground. The cover plates are held in place simply by their sheer weight. Despite the weight, however, the plates may be dislodged by traffic, vibration, or vandalism, leaving an opening in the ground that is dangerous to vehicles, people, and pets who pass by. Material loosened while digging the trench can thus also be exposed, flying into and breaking vehicle windshields. In locations where a plate is likely to be dislodged or must be left for a longer period of time, tar or asphalt is often laid around the perimeter of the cover to further secure it in place. This method is somewhat more secure, but requires additional effort, equipment and materials and makes intentional plate removal messy and more difficult. It is desirable to have a device for securing covers over access holes and trenches. 
     Holes and trenches come in many shapes, sizes and substrate materials. Holes may be circular or square. Trenches may cut a straight path, or have curves or corners. Some trenches and holes have straight vertical walls, while the walls are sloped in others. The substrate into which the hole or trench is cut may be composed of hard material like rock, or softer material like dirt or sand, into which it is difficult to anchor. For openings cut in asphalt or concrete, the cavity below the opening may undercut the opening, leaving an overhang of asphalt or concrete. A device used to secure covers over these openings must accommodate all sizes and shapes of trenches and holes, as well as a variety of substrate materials. 
     It is an object of this invention to provide a device which removably secures a cover to the ground. It is another object of this invention to provide a device which secures one or more cover plates to the ground in a way that prevents the cover from being inadvertently dislodged. It is another object of this invention to secure a cover to the ground in a way that it can be easily removed to inspect the hole or trench, or to backfill when work or inspection is complete. It is another object of this invention to provide a device which removeably secures the cover to asphalt, concrete, soil or other surface material. Another object is to provide an anchoring device that is weather resistant. 
     BRIEF SUMMARY OF THE INVENTION 
     The present invention provides an earth anchor to secure a cover over a trench or hole in the ground. The device has a retaining cap which is attached to a rod. Extendible arms are connected to the rod below the cap. The end of the rod opposite the cap is inserted into the hole or trench until the cap rests at ground level, either on top of a cover plate or on the ground itself. For large holes, the cap retains separate cover plates over the hole; for small holes, the cap acts as a cover itself. The arms are extended by a jack screw, rack and pinion, or other means until they contact the substrate or underside of the cover plates and clamp the same between the cap and the arms. The cover can be removed by reversing the motion of the jack screw or rack and pinion, and retracting the arms, thereby freeing the device to be removed from the hole. 
    
    
     BRIEF DESCRIPTION OF THE DRAWING 
     FIG. 1 is a perspective view of the first embodiment of the device employed in a trench, securing a cover plate to the ground over the trench. 
     FIG. 2 is a perspective view of the first embodiment of the device employed in a trench, securing cover plates to each other over the trench. 
     FIG. 3 is a top view of the first embodiment of the invention. 
     FIG. 4 is a side view of the first embodiment of the invention, showing the hinged arms partially extended by means of a jack screw. 
     FIG. 5 is a cross-section view of the first embodiment of the invention, showing the hinged arms in a closed position substantially parallel to the jack screw. 
     FIG. 6 is a side view of the first embodiment of the invention, showing the straight arms in a closed position. 
     FIG. 7 is a cross-section view of the first embodiment of the invention, showing the arms partially extended by means of a rack and pinion. 
     FIG. 8 illustrates a second embodiment of the device employed in a hole, showing use of the cap itself as the cover for the hole. 
     FIG. 9 illustrates a third embodiment of the device employed in a trench, securing cover plates to the ground and shoring trench walls. 
     FIG. 10 is a cross-section view of the third embodiment of the invention, showing the arms partially extended by means of a jack screw. 
    
    
     DESCRIPTION OF THE PREFERRED EMBODIMENTS 
     This invention is best understood by reading the following description in conjunction with reference to the accompanying FIGS. 1-10 in which like numerals refer to like parts throughout the drawings. FIG. 1 shows a first embodiment of the device, indicated generally as  10 , installed in a trench  9 , wherein the device serves to secure one or more cover plates to the ground. The device  10  is shown securing a cover plate  8  to the ground  6  so that the cover plate  8  does not lift up or otherwise become dislodged by traffic, vibration or vandalism. The device  10  is installed by inserting it through an aperture  5  in the cover plate  8  or, alternatively, abutting the edge of a cover plate, if no aperture is available, so that the lower portion of the device is suspended. An aperture  5  in the body of the cover plate  8  is shown at the distal end of the cover plate in FIG.  1 . (The aperture in the proximal end of the cover plate is hidden in the figures by the cap  12 .) An aperture  4  in the edge of the cover plate  8  is shown in FIG. 2. A cap  12  rests on top of the cover plate  8 . 
     As shown in FIG. 3, an aperture in the cap  12  allows access to the end of a rod  11 , which is connected to the cap  12  in a manner which allows the rod to turn independently of the cap  12 . At least one extendible arm  14  is slidably connected to the rod  11  so that when the rod is turned, the arm moves through a range of positions from a position substantially parallel to the rod to substantially perpendicular to the rod  11 . A jack screw or rack and pinion system is used to extend the arms, as described below. The arm  14  is extended until it contacts or penetrates the ground  6 . More than one arm  14  may be used to accommodate different trench sizes and cover plate configurations. Preferably two arms are used to secure a cover plate  8  over a hole or trench, the arms positioned opposite each other on the rod  11 , as shown in FIG. 1. A foot  15  is attached to each arm  14  to engage the ground more securely than the arm alone. The foot may be pivotally attached to the arm. Projections, or teeth, are added to the foot  15  to enable the foot  15  to better secure the anchor to the ground. When the device is to be removed, the rod  11  is turned in a reverse direction so that the arms retract. 
     The rod  11  can be attached to the cap  12  in any way which allows the cap  12  to float, i.e., the rod  11  turns while the cap  12  remains in place. A modified H-beam structure, indicated generally as  20 , is shown in FIGS. 3,  5 ,  6 , and  7 . Preferably the rod  11  does not extend above the cap  12  because a relatively smooth cap surface is desired so that vehicles driving over the cap  12  will have a smooth ride and tires will not be damaged. The edges of the cap  12  may be beveled to make the transition from the cap  12  to the ground or cover place more smooth. The rod  11  is encased in a tube  16 , having a slot  17  along the lengthwise axis of the tube to accommodate each arm as it extends through its full range of positions. The tube  16  is also attached to the cap  12 . The tube  16  adds structural integrity to the device, which must be rugged enough to survive heavy traffic for extended periods of time, and helps keep the means for extending the arms free of dirt and debris. If desired, a locking mechanism can be used to prevent the rod  11  from being turned by unauthorized personnel, thereby preventing the anchor from being removed and preventing dangerous situations from arising due to an uncovered hole or trench. 
     FIG. 2 shows the device  10  securing together two cover plates  8  used to cover the trench  9  to prevent objects or animals from falling in. Instead of clamping the cover plate  8  to the ground, as shown in FIG. 1, the device clamps the cover plate  8  to another cover plate  8 . Like the first embodiment above, the device  10  effectively secures the cover plate  8  to the ground so that it does not lift up or otherwise become dislodged by traffic, vibration or vandalism. Of course, a combination of the first embodiment and second embodiment may be utilized in the field, wherein one arm engages the ground and another arm engages another cover plate. 
     FIG. 8 shows a second embodiment of the device  10 , employed as the cover for a hole having an opening smaller than the cap  12 . The device is lowered into the hole  30  until the cap  12  rests on the ground  6 . The arms  14  are extended until they engage the ground  6  or, in a hole where the cavity has undercut the pavement, the arms clamp the cap  12  to the overhanging substrate. 
     To implement the ground anchor, the arms must be extended. Several means are available for transforming the circular motion of the turning rod  11  into an extension motion of the arm. FIGS. 1-5 and  8  show the present invention utilizing an externally threaded rod  11  in combination with an internally-threaded collar (hidden behind the cross-member  18  in the Figures) attached to hinged arms. The end of the rod  11  that is accessible through the cap  12  is configured to make the rod  11  easy to turn. For example, the end may be shaped to receive a flathead or Phillips screwdriver, an Allen wrench, or it may be shaped as a hexnut so that it can be easily turned with a lug wrench. When the rod  11  is turned in a forward direction, the collar follows the threads, causing it to move up the rod  11 , thereby extending the arms. When the device is to be removed, the rod  11  is turned in a reverse direction so that the arms retract. This configuration is commonly known as a jack screw. Refer to FIG. 5 which most clearly illustrates an embodiment with hinged arms. Each arm has two links, a first link  51  and a second link  52 . One end of each link is pivotally attached to a flange on the foot  15 , creating a single hinged arm having two links. The foot  15  is the point that is farthest from the rod  11  when the arm is extended. The free end  53  of the first link  51  is pivotally attached near the top of the rod  11  or tube  16 . The free end  54  of the second link  52  is attached to the collar. When the rod  11  is turned in a forward direction, the collar follows the threads, causing it to move up the rod  11  and closing the hinge point, thereby extending the arms. FIG. 4 shows the arms in an extended position. When the rod  11  is turned in a reverse direction, the collar moves down the rod  11  and opens the hinge point, thereby collapsing the arms. FIG. 5 shows the arms in a collapsed position. 
     FIG. 6 shows an embodiment with straight arms. One end of each arm  21  is pivotally attached to the collar (again, hidden behind the cross-member  18  in the Figures). When the rod  11  is turned in a forward direction, the collar follows the threads, causing it to move up the rod  11  and causing the arms to move from a position substantially parallel to the rod  11  to a position substantially perpendicular to the rod  11 . When the rod  11  is turned in a reverse direction, the collar moves down the rod  11  and the arms are collapsed. Multiple arms can be attached to the collar, so that the jack screw can operate more than one arm simultaneously. However, some situations may require that a single arm be used to secure the device in place, in which case the unused arm may hang suspended in mid-air. 
     Another means for extending the arms is a rack-and-pinion system shown in FIG.  7 . Instead of using hinged arms attached to a collar, single link arms are attached to a rack  70  having teeth  71 . The teeth  71  of the rack  70  mesh with the teeth  77  of a pinion gear  72  which is coaxial with the rod  11 . The rack  70  is substantially perpendicular to the rod  11  and cooperates with the pinion gear  72  to extend the arms in a direction substantially perpendicular to the rod  11 . The pinion gear  72  is internally threaded to travel up and down the rod  11 . The rod  11  is turned to cause the pinion gear  72  to moved to the desired height. Once the desired height is reached, the clutch spring  74  is activated to drop the clutch gear  74  into place and engage the pinion gear  72 . As the rod  11  is turned in a forward position, the clutch causes the pinion gear  72  to rotate and extend the rack  70 , so that the arms are forced into the sides of the hole or trench. In a hole where the cavity has undercut the pavement, the arms clamp the cap  12  to the overhanging substrate. When the device is to be removed, the rod  11  is turned in a reverse direction so that the arms retract. 
     The third embodiment of the invention is shown in FIGS. 9 and 10. The foot is replaced with a plate which can be used to shore up the sides of the trench or hole, as shown in FIGS. 9 and 10. The shoring plates  90  are pivotally attached to a mounting flange  91  of the shoring arms  92  to shore up walls  93  of a trench  9 . Preferably the shoring arms  92  are extended by means of a jack screw. The device is installed by inserting the rod  11  into the trench until the cap  12  rests on the ground or pavement, providing support for the device to hang in the cavity. As the rod  11  is turned, the arms extend until the plates abut the walls of the cavity, thereby shoring up the walls. 
     Preferably the cap  12  and tube  16  are made of material sturdy enough to withstand heavy traffic and weather, preferably steel. The mechanical components, such as the rod, collar, pinion gear, may instead be made of a high-strength, weather resistant material such as nylon or plastic. To prevent the device from being dislodged due to dynamic vibration caused by traffic, a dampening spring may be included between the cap and the arms. 
     The objects of this invention are achieved through the aforementioned improvements. It will be understood that various modifications may be made to the ground anchor and the method of using it without departing from the purview of the appended claims. Although certain preferred embodiments have been shown and described, it should be understood that other embodiments and modifications that achieve these objects may be apparent to those of skill in the art and are within the scope of the appended claims.