Abstract:
A folding sawhorse created by two pivotally connected frames containing a plurality of stress bearing structures on their inner surfaces forms a 60 degree angle when locked in place by a locking shelf. The frame components include two parallel vertical members separated at a distance by an upper horizontal brace and parallel lower horizontal brace. A U-shaped load bearing support is connected to the upper surface of the upper horizontal braces and provides four surfaces across which a load may be distributed when the folding sawhorse is in use. The trapezoidal locking shelf is pivotally connected to the lower horizontal braces and contains a central hinge, allowing the shelf to fold when the sawhorse is collapsed along its central vertical hinge.

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
     This application claims priority to and is a continuation-in-part of U.S. application Ser. No. 13/248,005, filed Sep. 28, 2011 now abandoned and titled “Folding Sawhorse,” which is hereby incorporated by reference in its entirety. U.S. application Ser. No. 13/248,005 claims the benefit of U.S. application Ser. No. 13/156,326, which is a continuation of U.S. application Ser. No. 10/908,388, which applications are also hereby incorporated by reference in their entirties. 
    
    
     FIELD OF INVENTION 
     The present invention relates to sawhorses, scaffolds and trestles. In particular, the present invention relates to sawhorses that are opened for use and folded to collapse for storage. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  is a front perspective view of a folding sawhorse according to the present invention. 
         FIG. 2  is a back perspective view of a folding sawhorse. 
         FIG. 3  is a top view of a folding sawhorse. 
         FIG. 4  is a perspective view of a folding sawhorse in a closed position. 
         FIG. 5  is a side view of a folding sawhorse in a closed position. 
         FIG. 6  is a top view of a load bearing support member of a folding sawhorse. 
         FIG. 7  is a side view of a frame of a folding sawhorse. 
         FIG. 8  is a side view of a hinge of a folding sawhorse. 
         FIG. 9  is a perspective view of a frame of a folding sawhorse. 
         FIG. 10  is a top view of a load bearing support member of a folding sawhorse. 
         FIG. 11  is a side view of a frame of a folding sawhorse. 
         FIG. 12  is a side view of a hinge of a folding sawhorse. 
         FIG. 13  is a perspective view of a frame of a folding sawhorse. 
         FIG. 14  is a top view of a shelf of a folding sawhorse. 
         FIG. 15  is a perspective view of a shelf of a folding sawhorse. 
         FIG. 16  is a perspective view of a hinge of a folding sawhorse. 
         FIG. 17  is a perspective view of a hinge of a folding sawhorse, 
         FIG. 18  is a top view of a shelf of a folding sawhorse. 
         FIG. 19  is a perspective view of a shelf of a folding sawhorse. 
         FIG. 20  is a perspective view of a hinge of a folding sawhorse. 
         FIG. 21  is a perspective view of a hinge of a folding sawhorse. 
         FIG. 22  is a perspective view of a tubular member of a hinge for a folding sawhorse. 
         FIG. 23  is a side view of a tubular member of a hinge for a folding sawhorse. 
     
    
    
     TERMS OF ART 
     As used herein, the term “stabilizing surface” refers to any structure or component of a folding sawhorse adapted to be in physical contact with the ground or other surface while the sawhorse is in use. 
     As used herein, the term “stress bearing structures” refers to any structure which supports or resists a loads or stress, including, but not limited to, bending, tensile stress and compression. 
     BACKGROUND 
     Sawhorses are used as racks or trestles to support construction materials and other objects. With their wide base, sawhorses provide stable support for a work piece while being portable. Non-folding sawhorses, however, require a substantial amount of space for storage and transportation. To ameliorate this problem, sawhorses were designed to fold and collapse. 
     Unfortunately, many current folding sawhorses are unable to withstand sideways motion in the load they support. In particular, folding sawhorses with legs positioned on a common side are not in rigid contact with each other which results in the legs pivoting with respect to the upper central member of the sawhorse when the sawhorse is under load. 
     Other folding sawhorse designs require the of two sawhorses to support working materials or equipment in a horizontal position. While providing adequate support, the necessity of having two separate sawhorses is cumbersome and onerous. 
     Therefore, what is needed is a single folding sawhorse that easily unfolds and supports a variety of working materials. What is further needed is a folding sawhorse that is capable of supporting a bad while withstanding the effects of lateral movement of the particular bad. Finally, what is needed is a folding sawhorse that is constructed from lightweight materials. 
     SUMMARY OF THE INVENTION 
     The present invention is a folding sawhorse comprised of two pivotally connected frames containing a plurality of stress bearing structures on their inner surfaces and forming a 60 degree angle when locking in place by a locking shelf. The frame components are comprised of two parallel vertical members separated at a distance by an upper horizontal brace and parallel lower horizontal brace. A U-shaped bad bearing support is connected to the upper surface of the upper horizontal braces and provides four surfaces across which a load may be distributed when the folding sawhorse is in use. The trapezoidal locking shelf is pivotally connected to the lower horizontal braces and contains a central hinge, allowing the shelf to fold when the sawhorse is collapsed along its central vertical hinge. 
     DETAILED DESCRIPTION OF INVENTION 
     For the purpose of promoting an understanding of the present invention, references are made in the text to exemplary embodiments of a folding sawhorse, only some of which are described herein. It should be understood that no limitations on the scope of the invention are intended by describing these exemplary embodiments. One of ordinary skill in the art will readily appreciate that alternate but functionally equivalent structures and materials may be used. The inclusion of additional elements may be deemed readily apparent and obvious to one of ordinary skill in the art. Specific elements disclosed herein are not to be interpreted as limiting, but rather as a basis for the claims and as a representative basis for teaching one of ordinary skill in the art to employ the present invention. 
     It should be understood that the drawings are not necessarily to scale; instead, emphasis has been placed upon illustrating the principles of the invention. In addition, in the embodiments depicted herein, like reference numerals in the various drawings refer to identical or near identical structural elements. 
       FIGS. 1-3  illustrate folding sawhorse  10  in the fully opened position. In the exemplary embodiment shown, folding sawhorse  10  is generally V-shaped with a first trestle frame  12  and a second trestle frame  14  connected to one another with a central hinge  16 . 
     Frames  12  and  14  are generally rectangular having central rectangular apertures  80  and legs  40   a ,  40   b  and  52   a ,  52   b  projecting downward from frames  12  and  14 , respectively. In the exemplary embodiment shown, legs  40   a ,  40   b  and  52   a ,  52   b  are integral with frames  12  and  14 , respectively. However, in further exemplary embodiments, legs  40   a ,  40   b  and  52   a ,  52   b  may be separate physical components of folding sawhorse  10  which may be permanently or removably interconnected with frames  12  and  14 . 
     As illustrated, legs  40   a ,  40   b  and  52   a ,  52   b  work together to create a three-point contact with the ground or other surface for while sawhorse  10  is in use. Legs  40   a  and  52   a , closest to central hinge  16 , act as a single stabilizing surface, while legs  40   b  and  52   b , furthest from central hinge  16 , act as distinct stabilizing surfaces. 
     Also illustrated in  FIGS. 1-3  are the surfaces of frames  12  and  14 . In the exemplary embodiments shown, frames  12  and  14  contain smooth outer surfaces while the inner surfaces contain a plurality of structural trusses, struts and other stress-bearing structures molded within frames  12  and  14 . 
     As illustrated, there are three types of stress-bearing structures included on each of frames  12  and  14 . Running vertically from legs  40   a ,  40   b  and  52   a ,  52   b  to the top of frames  12  and  14  are horizontal supports  90   a , which are alternately aligned between vertical supports  90   b . Horizontal supports  90   a  and vertical supports  90   b  spread and distribute force horizontally over legs  40   a ,  40   b  and  52   a ,  52   b  so that weight (when folding sawhorse  10  is in use) is evenly distributed on legs  40   a ,  40   b  and  52   a ,  52   b . Frames  12  and  14  also contain diagonal braces  92   a  with vertical struts  92   b  running horizontally above the frame apertures  80 . The diagonal braces  92   a  with vertical struts  92   b  work to distribute weight evenly across load bearing supports  42  and  54 . Finally, the lower portions of frames  12  and  14  contain diamond-shaped support structures  94  which help evenly distribute weight from load bearing supports  42  and  54  and shelf  20  between legs  40   a ,  40   b  and  52   a ,  52   b.    
     A center folding shelf  20  controls the opening and closing movements of frames  12  and  14 . Shelf  20  is attached to a lower strut  22  on frame  12  and a lower strut  24  on frame  14 . In particular, shelf  20  is interconnected with strut  22  with a shelf hinge  26  and with strut  24  with shelf hinge  28 . Shelf  20  further includes a central shelf hinge  30  and is generally trapezoidal. Shelf  20  locks sawhorse  10  in an open stable position while also providing a surface upon which a user may place tools and parts associated with a particular job. 
     In the exemplary embodiment illustrated, shelf  20  contains a lip to prevent items from rolling on shelf  20 . However, in other further embodiments, shelf  20  may omit lip. In still further exemplary embodiments, shelf  20  may contain apertures or compartments to accommodate specific tools or accessories commonly used in the art. 
       FIGS. 4-5  illustrate folding sawhorse  10  in closed position. In operation, sawhorse  10  is opened from a closed position (illustrated in  FIGS. 4-5 ) by slightly spreading apart frames  12  and  14  to an unfolded working position (as illustrated in  FIGS. 1-3 ). Sawhorse  10  remains in a locked open position without any additional latching mechanism until frames  12  and  14  are returned to a closed position by applying light upward pressure on central shelf hinge  30 . Shelf  20  then roves upwardly, thereby causing frames  12  and  14  to pivot inwardly towards each other until frames  12  and  14  are in a closed position. 
     In the preferred embodiment, frame  12  includes a first vertical member  32  opposite and parallel to a second vertical member  34  having an upper horizontal brace  36  and a lower horizontal brace  38  orthogonally configured therebetween. A pair of parallel spaced apart legs  40   a ,  40   b  extends from and is integrally formed with lower horizontal brace  38 . A load bearing support  42  is formed along the top edge of upper horizontal brace  36 . 
     Similarly, frame  14  includes a first vertical member  44  opposite and parallel to a second vertical member  46  having an upper horizontal brace  48  and a lower horizontal brace  50  orthogonally configured therebetween. A pair of spaced apart legs  52   a ,  52   b  extends from and is integrally formed with lower horizontal brace  50 . A bad bearing support  54  is formed along the top edge of upper horizontal brace  48 . 
     The inner surfaces of vertical members  32 ,  34 ,  44  and  46  contain horizontal supports  90   a  and vertical supports  90   b  (not shown). Upper horizontal braces  36  and  48  contain diagonal braces  92   a  with vertical struts  92   b  (not shown). Lower horizontal braces  38  and  50  contain diamond-shaped supports  94 . 
     In the exemplary embodiments shown in  FIGS. 1-5 , load bearing supports  42  and  54  are U-shaped, thereby forming a channel across the upper edges of horizontal braces  36  and  48 , respectively. When folding sawhorse  10  is in use, an object placed across the top of folding sawhorse  10  will be in physical contact with the four upper surfaces ( 42   a ,  42   b  and  54   a ,  54   b ) of the U-shaped load bearing supports  42  and  54 . 
     Frames  12  and  14  pivot about hinge axis  16  along vertical leg edge  18  parallel to legs  40   a ,  40   b  and  52   a ,  52   b  and perpendicular to braces  36 ,  38 ,  48  and  50 . Trapezoidal shelf  20  includes a first side  56  interconnected via hinge  26  to lower horizontal brace  38  of frame  12 , and a second side  58  interconnected via hinge  28  to lower horizontal brace  50  of frame  14 . 
     In the open position, trapezoidal shelf  20  is perpendicular to central hinge  16  that interconnects frames  12  and  14 , thereby resulting in a “V” shaped configuration between frames  12  and  14  connected at hinge  16 . In a closed storage position, frame  12  is generally parallel to frame  14  with trapezoidal shelf  20  folded therebetween. In the open position, shelf  20  rigidly secures legs  40   a ,  40   b  and  52   a ,  52   b  in position so they do not move with respect to one another. The rigid positioning of legs  40   a ,  40   b  and  52   a ,  52   b  combined with central hinge  16  securing frame  12  to frame  14  prevents relative motion between the components of sawhorse  10 , resulting in a rigid support structure designed to accommodate a substantial load. 
     In the exemplary embodiments shown, frames  12  and  14  have a length of 30 inches and a height of 31 inches. When locked in its open position, frames  12  and  14  create a 60 degree angle. Legs  40   a ,  40   b  and  52   a ,  52   b  are 4 inches wide by 1.75 inches deep, resulting in a surface area for each of 7 inches squared. Because legs  40   a ,  40   b  and  52   a ,  52   b  work together to create three stabilizing areas, the resulting stabilizing surfaces are 7 inches squared (for legs  40   b  and  52   b ) and 14 inches squared (for combined legs  40   a  and  52   a ). 
     While the above-dimensions are preferred, in further exemplary embodiments, frames  12  and  14  may have slightly variable dimensions. For example, frames  12  and  14  may be specifically manufactured for use with a certain material or weight. In some exemplary embodiments, the length and height of frames  12  and  14  may range between 25 and 35 inches. In most exemplary embodiments, frames  12  and  14  will have the same length and height. 
     Similarly, the 7-inches-squared surface area of legs  40   a ,  40   b  and  52   a ,  52   b  is preferred because a smaller surface area will not provide enough stability and it may be difficult to find a level surface to stabilize legs having a larger surface area. However, in further exemplary embodiments, the surface area of legs  40   a ,  40   b  and  52   a ,  52   b  may range from 5 to 10 inches squared. 
     In still further exemplary embodiments, frames  12  and  14  may create a different angle. For example, frames  12  and  14  may create an angle in the range of 50 to 70 degrees. 
       FIGS. 6-9  illustrate the separate components of frame  12 , with frame  14  (not shown) being symmetrically formed. As previously described, load bearing support  42  is formed along top edge of upper horizontal brace  36 . Central hinge  16  interconnects frame  12  with frame  14 . 
       FIG. 7  clearly illustrates the different stress bearing structures integrally molded with frame  12 . The inner surfaces of vertical members  32 ,  34 ,  44  and  46  contain horizontal supports  90   a  (not shown) with vertical supports  90   b . Upper horizontal braces  36  and  48  contain diagonal braces  92   a  (not shown) with vertical struts  92   b  (not shown). Lower horizontal braces  38  and  50  contain diamond-shaped supports 
       FIGS. 14-17  illustrate the components of shelf side  56  of shelf  20 . Central shelf hinge  30  connects side  56  to shelf side  58 . Hinge  26  interconnects side  56  to frame  12 . Similarly, as illustrated in  FIGS. 18-21 , central shelf hinge  30  connects side  56  to shelf side  58 . Hinge  28  interconnects side  58  to frame  14 .  FIGS. 22 and 23  illustrate a tube member  60  which is part of hinge  16 . 
     In the exemplary embodiments shown, hinges  30 ,  26  and  28  are created by a plurality of looped members  99  through which tube member  60  passes to form pivotal joints. As illustrated in  FIGS. 22 and 23 , tube member  60  is generally cylindrical having notched segments  62  alternated with smooth segments  64  and provides a surface around which frames  12  and  14  and shelf sides  56  and  58  may pivot to go from the open position to the closed position. 
     In the exemplary embodiments described, sawhorse  10  is manufactured from a lightweight plastic material. In further exemplary embodiments, however, sawhorse  10  may be manufactured from other materials, including wood. Similarly, shelf  20  is described in the exemplary embodiments as trapezoidal, but may be any other shape while still functioning as a locking mechanism between frame  12  and frame  14 . Frames  12  and  14  may also be constructed as single continuous panels without separate vertical members and horizontal braces.