Patent Publication Number: US-11377817-B2

Title: Device to remove gravel from a roof

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
     This application claims the benefit of provisional patent application 62/733,173 filed Sep. 19, 2018, which is hereby incorporated by reference. 
    
    
     STATEMENT REGARDING FEDERALLY SPONSORED RESEARCH 
     Not Applicable. 
     APPENDIX 
     Not Applicable. 
     BACKGROUND OF THE INVENTION 
     Field of the Invention 
     The present invention relates to removing gravel from a roof, and more particularly to a device using a drive mechanism and a serrated blade to remove gravel from a roof. 
     Related Art 
     The present invention relates to removing gravel from asphalt-coated flat roofs so that they may be repaired. Such roofs, mostly on commercial buildings, are built according to a standard procedure where layers of asphalt saturated felt are laid upon the roof surface to create an asphalt deck and cemented together with a coating of hot-mop asphalt or tar with the top layer being a comparatively thick coating of hot-mop asphalt or tar covered with a layer of small generally uniform rocks such as pea gravel or the like. The rocks forming the layer of gravel embed themselves into the asphalt to protect the roof covering, the asphalt, and the underlying felt sheets against physical damage and weather deterioration especially by sunlight. 
     A good average life for such a roof may be approximately ten years, at which time it must be repaired and rehabilitated. The common procedure for removing the rock is by sweeping the roof with heavy brooms. This is a very onerous, slow chore where the workmen are required to wear dust masks because of the large amounts of fine dust stirred up by the sweeping and dumping the gravel from the roof to a truck. 
     Alternatively, a rotary planer, such as a Garlock rotary planar, is used by workers who push to propel the device, and apply downward pressure to this heavy machine to slowly and laboriously remove gravel from a roof. 
     There has been a desire for a more effective and easier to use device to remove gravel from a roof. More specifically, it is desirable to have a riding device that removes gravel from a roof. 
     SUMMARY OF THE INVENTION 
     The present invention is a device to remove gravel adhering to a roof that has a vertically mounted blade assembly attached to a drive mechanism. The blade assembly includes a horizontal serrated blade and, optionally, a horizontal smooth blade. More specifically, the present invention is a riding drive mechanism, such as a tractor, having vertically mounted on the front of the tractor a blade assembly that includes a smooth blade with a horizontal edge, such as used for snow plowing, and, mounted proximate and parallel to the smooth blade, a serrated blade. Either the smooth blade or the serrated blade, or both blades have an up position and a down position. In a preferred embodiment, the blade assembly includes a mechanism to move the blades from the down position to the up position and back. In the down position, the blade or blades engage with the gravel to remove it from the roof. In one embodiment, in the down position, the serrations extend below the lower edge of the smooth blade and in the up position, the serrations are even with or above the edge of the smooth blade. Optionally, mounted on the either blade is at least one weight to provide a downward force. 
     Further areas of applicability of the present invention will become apparent from the detailed description provided hereinafter. It should be understood that the detailed description and specific examples, while indicating the preferred embodiment of the invention, are intended for purposes of illustration only and are not intended to limit the scope of the invention. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       The present invention will become more fully understood from the detailed description and the accompanying drawings, wherein: 
         FIG. 1  is a side perspective of an embodiment of the device to remove gravel of this invention; 
         FIG. 2  is a front perspective of an embodiment of the blade assembly having a serrated blade mounted on a smooth blade of the present invention; 
         FIG. 3  is a side perspective of an embodiment of the blade assembly having the serrated blade mounted on the smooth blade, with the serrated blade in the down position; 
         FIG. 4  is a side perspective of the serrated blade mounted on the smooth blade, with the serrated blade in the up position; 
         FIG. 5  is a front perspective of the serrated blade in the down position being used to loosen gravel; 
         FIG. 6  is a raised front cut away perspective of the smooth blade being used to scoop up lose gravel and move it; 
         FIG. 7  is a side perspective of an embodiment of the blade assembly; and 
         FIG. 8  is a raised side perspective an embodiment of the blade assembly. 
     
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS 
     The following description of the preferred embodiment(s) is merely exemplary in nature and is in no way intended to limit the invention, its application, or uses. 
     An embodiment of the claimed device is shown as  100  in  FIG. 1 . A driving mechanism,  10  is shown as a tractor. However, any drive mechanism, such as a truck, riding lawn mower, etc., could be used. A riding lawn mower is preferred, as it is small enough to be easily transported and raised onto a roof. Vertically mounted on the front end of the tractor is a smooth blade  1 , which is typically used as snow plow blade. The smooth blade  1  has a lower horizontal edge  4 . The smooth blade is mounted on the tractor has a smooth blade pivot point  8  which pivots the smooth blade to the up position for non-use and to the down position to contact the lower edge  4  with the asphalt deck and scrape the deck smooth and clear. The smooth blade is held by smooth brace arms  6  and moved by ball screw  7 . Mounted in front of the smooth blade is the serrated blade  3  having an up position and a down position. In a preferred embodiment, the serrated blade is attached to the smooth blade by means of serrated brace arms  26  and pivot arms  2 , which connect at a brace pivot point  5 . In the embodiment of  FIG. 1 , the serrated blade  3  is moved manually to the up position and to the down position by pivoting at pivot point  5 . In this embodiment, there are two pivot points; the smooth blade and the serrated blade each have separate pivot points. In the down position, the serrated blade  3  projects  18  below the smooth blade  4 . This allows both the smooth blade and the serrated blades to be in the down position when the serrated blade is being used to remove gravel from a roof which further allows the serrated blade to be reinforced from behind by the smooth blade without interfering with the use of the serrations of the blade. Providing a downward force is weight  16  which is attached to the top of the smooth blade  1 . This effectively provides a downward force for both the smooth blade and the serrated blade. In another embodiment, there is a weight on both blades, independently. Optionally, a weight storage box  17  can be attached to the tractor. An alternator  9  is part of the tractor  10 . 
     The downward force can be provided by other mechanical sources such as hydraulic or pneumatic cylinders, compressed springs, screw-devices, etc. 
     As shown in  FIG. 2 , the serrated blade  3  is attached to the smooth blade  1  by serrated brace arms  26  and more than one pivot arms  2  which have a brace pivot point  5 . 
     In  FIG. 3 , in a preferred embodiment, the blade assembly has a serrated blade  12  in the down position. It is moved from the down position to the up position by the ball screw  15 , as shown in  FIG. 4 . This allows the operator of the device to raise and lower the serrated blade while seated and operating the riding device. Other driving devices, including hydraulic and pneumatic cylinders, cams, etc. can also be used to move the serrated blade  12  from the up position to the down position. Further, in  FIGS. 3 and 4 , the smooth blade  11  has a lower edge  14 . The serrated blade  12  projects below the lower edge  14 . 
     As shown in  FIG. 5 , the serrated blade  3  has teeth  34  along its horizontal edge. The teeth have a depth  31  a width  33  and a gap width  32 . Preferably, the teeth have a squared shape, with approximately straight dimensions. The flat leading edge is effective in scraping the gravel off the flat roof. The dimensions of the teeth are critical to the success of the teeth in removing gravel  20  from a roof. The preferred tooth width  33  is from about 1.0 to 1.5 inches. A more preferred is from about 1.0 to about 1.0624 inches. A preferred gap width  32  is from about 1.0 to 1.5 inches. A more preferred gap is from about 1.4 to 1.6 inches. A preferred depth  31  is from about 1.1 to 0.875 inches. A more preferred depth is about 1.0 to 0.90 inches. If the dimensions are greater or less than disclosed and claimed, the teeth do not penetrate between the gravel  20  and work to dislodge it. 
     Preferably, the serrated blade is made of a modified road grader blade. A typical blade has the dimensions of 6 inches by 1.5 feet by about ⅝ inches thick steel. A preferred steel is 6150 tooled steel from about ¼ to about 1 inch thick. The steel needs to have sufficient strength and inflexibility that, once modified with teeth, the teeth do not bend or break while in use. In a preferred embodiment, the blade is tapered from about 9/16 to 3/16 inch at the edge of the blade. 
     When using the serrated teeth blade on a gravel roof, the serrated blade is moved to the down position and the teeth  34  penetrate to between the gravel particles  20  adhering to the roof, as is show in  FIG. 5 . As the blade is moved forward by the tractor, the gravel is dislodged from the roof and becomes loose gravel  21 . Typically this requires multiple passes over the gravel, from about two to three passes by the tractor to dislodge all the gravel  20 . After that, the serrated blade is moved to the up position and the tractor then moves the smooth blade, as shown in  FIG. 6  to scrape the loose gravel  21  clean to be removed from the roof. 
       FIGS. 7 and 8  are perspectives of a preferred embodiment of the blade assembly. The smooth blade  101  and the serrated blade  103  are moveably attached to pivot rod  111 . In this embodiment, there is one pivot rod for both blades. Fixedly attached to pivot rod is backstop  109  which is located behind the blades, is approximately vertical, and extends about the length of the blades proximate the ground. Attached to the smooth blade  101  and beyond the pivot rod  111  is the smooth blade actuator lever  107 . When the lever is actuated, the smooth blade pivots around the pivot rod  111  and moves to the up position. When the lever is returned to the unactuated position, the smooth blade pivots back to the down position. Likewise, attached to the serrated blade  103  is a serrated blade actuator lever  105 , which acts to move the serrated blade from the down position to the up position and back. When either blade is in the down position, the backstop  109  reinforces and holds the blade in the desired vertical position. Preferably the pivot rod  111  is anchored to the frame of a drive mechanism such as a tractor, which provides a downward force. 
     Prior art devices have used serrations, sharp and tooth-like to scrape roofs to remove shingles. These devices are used horizontally, lying on the roof, to catch shingles or nails. When these devices are used on gravel, they merely pass over the gravel and do not loosen it. Devices that do not have the required dimensions of the serrations of the present invention merely pass over the gravel and do not loosen it. It is only by the claimed combination of a vertically mounted blade assembly having a serrated blade with novel serration dimensions, a forward force, and a downward force that the gravel is effectively scraped off and removed. When the serrated blade is applied to the roof to remove the gravel, it is approximately perpendicular to the roof. 
     The embodiments were chosen and described to best explain the principles of the invention and its practical application to persons who are skilled in the art. As various modifications could be made to the exemplary embodiments, as described above with reference to the corresponding illustrations, without departing from the scope of the invention, it is intended that all matter contained in the foregoing description and shown in the accompanying drawings shall be interpreted as illustrative rather than limiting. Thus, the breadth and scope of the present invention should not be limited by any of the above-described exemplary embodiments, but should be defined only in accordance with the following claims appended hereto and their equivalents.