Abstract:
Embodiments of a foldable sawhorse are shown and described, which may be collapsed to a very flat shape, with one of the leg frames fitting inside the central open area of the other so that the two leg frames are co-planar. This way, the two leg frames preferably do not contact each other except at their mutual pivot point(s), and they do not interfere with each other. Preferably, the bottom surfaces of all portions of the sawhorse that touch the ground are broad, smooth, substantially continuous across the whole width of the sawhorse. The bottom surfaces preferably have no protrusions, such as feet, that might promote sinking into the ground or catching excessively on the ground/floor. The preferred sawhorse has one or more platforms that are fixedly attached to their respective parts of the sawhorse in such ways and in such angles that their top platform surfaces are level with the ground or other supporting surface when the sawhorse is unfolded.

Description:
DESCRIPTION  
       [0001]    This application claims priority of my prior provisional application, Serial No. 60/198,858, filed Apr. 21, 2000, entitled “Foldable Sawhorse.” 
     
    
     
       BACKGROUND OF THE INVENTION  
         [0002]    1. Field of the Invention  
           [0003]    The present invention relates, generally, to folding sawhorses. More particularly, the invention relates to a folding saw horse that has a thin profile when folded. The folding sawhorse also has a system for allowing easy movement of the sawhorse on the ground or shop floor, and may also has supporting platforms at two levels relative to the ground.  
           [0004]    2. Related Art  
           [0005]    Several folding sawhorses are discloses in the prior art. Such sawhorses include: U.S. Pat. No. 5,078,352 (Brow); U.S. Pat. No. 5,560,448 (Yemini); U.S. Pat. No. 5,560,449 (Smith); U.S. Pat. Nos. 5,647,455 (Russell); and 5,839,540 (Russell). Typically, conventional foldable sawhorses are bulky when folded because the two legs can pivot together, at most, an amount that places the feet together but maintains a V-shape, as shown in FIGS. P-A, P-B, P-C, and P-D.  
           [0006]    FIGS. P-A is a side view of the prior art sawhorse in an unfolded position, and FIGS. P-B is a side view of the prior art sawhorse in a folded position. One may see that the unfolded sawhorse takes the shape of a wide-spread V with thickness T 1 , and the folded sawhorse still retails the shape of a V, albeit a more narrow one. Although the prior art sawhorse&#39;s two leg frames pivot on a single axis at the top of the sawhorse, the leg frames get in each other&#39;s way when folded, so that a V-shape with a thickness T 2  equal to at least the sum of the thicknesses of each leg.  
           [0007]    Typically, these prior art sawhorses have four feet that protrude downward from the legs and/or the transverse members at the bottom end of the sawhorse, wherein the transverse members are only for reinforcement rather than for providing a surface for ground contact. The conventional feet may be seen to best advantage in FIGS. P-C, a front perspective view of the prior art sawhorse in the unfolded position, and FIGS. P-D, a front view of the folded sawhorse. The feet tend to poke into, or excessively frictionally engage, the ground or other surface upon which the sawhorse stands. These relatively small conventional sawhorse feet tend to dig into, or shift unpredictably on, dirt or gravel, making them unsafe in many circumstances. Also, because the feet dig into or grip the ground, the sawhorse is difficult to move, either when one needs to move it for improved positioning during use or for transport to an alternative work location or for storage.  
         SUMMARY OF THE INVENTION  
         [0008]    The present invention includes a foldable sawhorse with two leg frames that are pivotally connected. The sawhorse includes leg frames that may be called rectangular or U-shaped and are pivotally connected together at their top ends. The invented sawhorse includes a platform connected to the top ends of the leg frames in a position that places its flat top surface parallel to the ground or surface upon which the sawhorse is placed, when the sawhorse is unfolded. The two leg frames are adapted so that one of the leg frames pivots into the other, so that the two leg frames lie on the same plane when the sawhorse is folded (“collapsed”). This way, the sawhorse folds into a very thin, compact shape for carrying or storage.  
           [0009]    Preferably, the adaptation that allows the sawhorse to collapse to a very flat shape and yet to have horizontal platform(s) when unfolded involves having an asymmetrical structure. Preferably, one leg frame is larger than the other, so that the smaller leg frame fits completely inside the larger leg frame when the sawhorse is collapsed. Platform attachment and positioning is adapted to cooperate with this asymmetrical structure to provide horizontal upper surfaces for support of objects during use of the sawhorse.  
           [0010]    The two leg frames preferably include elongated, solid members as the bottom members that rest on the ground or other surface. These bottom members preferably extend across the entire width of the sawhorse with no significant protrusions, to present a solid, smooth, continuous, substantially horizontal surface for the sawhorse to rest on. This way, the sawhorse may rest in a secure and stable position on a wide variety of surfaces, even slightly uneven surfaces, and is not likely to suddenly shift position, tip, or slant. Also, the preferably-horizontal bottom member surface provides a smooth and broad surface for contact with the ground, concrete, or other support surface, so that the invented sawhorse does not sink into the support surface, and may be easily slid along the support surface when desired. This way, it is easy to adjust the exact location of the sawhorse relative to equipment or work-pieces, or to slide the sawhorse across a shop floor or construction site.  
           [0011]    Preferably, one or more securement members are included to limit leg frame movement to the desired open, unfolded position when in use. For example, chains or other flexible tie members may be included on the sawhorse, to connect the first leg frame to the second leg frame, preferably at two positions about half way down the leg frames on the left side and the right side of the sawhorse.  
           [0012]    The first leg frame is preferably generally a rectangle with an open space between a bottom bar which serves as the above-mentioned bottom member, and two side bars. The second leg frame is also generally rectangular, with a bottom member for placement on the ground or support surface (that is, a first horizontal or transverse member), two side members preferably pivotally connected at their top to the first leg frame. Preferably, the second leg frame also has a second horizontal or transverse member connected the two side members to further strengthen and rigidize the second side frame. Preferably, this second transverse member connects the side members at about midway down the second leg frame.  
           [0013]    The second leg frame to pivotally attached inside the first leg frame and is smaller in width and in length than the first leg frame, so that the second leg may pivot into, and lie in the same plane, as the first leg frame. Because the second leg frame is shorter than the first leg frame, measured from the top end of the sawhorse at the connection point(s) of the two leg frames, the top platform must be attached to the sawhorse so that the plane of its top surface is non-normal (as well as non-parallel) to the plane of the folded legs. This way, when the sawhorse is unfolded, the plane of the top platform moves to horizontal to provide a flat horizontal surface for supporting workpieces, tools, boards, etc..  
           [0014]    Optionally, the sawhorse may include a second platform, preferably generally mid-way down on the sawhorse. Preferably, the second platform is part of, or acts as, a second transverse member of the second leg frame for strengthening and rigidizing the second leg frame. The second platform is connected to the sawhorse in a manner that places the top surface of the second platform horizontal when the sawhorse is unfolded. Typically, this may be done by connecting the second platform so that its top surface is slightly angled relative to horizontal when the sawhorse is folded (and held vertical as in FIG. 5), and, in effect, the platform position moves to horizontal when the sawhorse is unfolded and set up with legs separated.  
           [0015]    The invented foldable sawhorse provides surprising stability during use, even though its pivotal leg portions are not the same length and the top platform is not centered over the depth of the legs (from bottom end of the one leg to the bottom end of the other leg D). The inventor has found that symmetry is not necessary, that this asymmetrical sawhorse is extremely stable, and the asymmetry allows for a very compact collapsed device for storage and transport. 
       
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       [0016]    FIGS. P-A is a side view of one prior art foldable sawhorse, in an unfolded, set-up position.  
         [0017]    FIGS. P-B is a side view of the prior art sawhorse of FIGS. P-A, in a folded position.  
         [0018]    FIGS. P-C is a front, perspective view of the sawhorse of FIGS. P-A and P-B, in the unfolded position.  
         [0019]    FIGS. P-D is a front view of the saw horse of FIGS. P-A, B, and C, in the folded position.  
         [0020]    [0020]FIG. 1 is a front view of one embodiment of the invented foldable sawhorse with a single platform.  
         [0021]    [0021]FIG. 2 is a left end view of the embodiment of FIG. 1, in a collapsed (folded) position.  
         [0022]    [0022]FIG. 3 is a left end view of the embodiment of FIGS. 1 and 2 in an extended (unfolded) position.  
         [0023]    [0023]FIG. 4 is a front end view of an alternative embodiment of the invention with two platforms, one on top of the sawhorse and one approximately mid-way down one leg frame.  
         [0024]    [0024]FIG. 5 is a right end view of the embodiment of FIG. 4, showing the oppositely-slanted positions of the top and middle platform that are necessary to place the platform top surfaces flat and horizontal when the sawhorse is opened (unfolded) on a horizontal surface G.  
         [0025]    [0025]FIG. 6 is a right end view of the embodiment of FIGS. 4 and 5, unfolded with the result of level horizontal platforms.  
         [0026]    [0026]FIG. 7 is a front view of an alternative view of the invented sawhorse with a telescoping leg frame feature.  
         [0027]    [0027]FIG. 8 a  is a front, partial view of one embodiment of a connection system having clamp members for connecting a transverse member to a leg frame of the invention. FIG. 8 b  is a top, partial view of the connection system of FIG. 8 a , with the clamp members loosened for illustration. 
     
    
     DETAILED DESCRIPTION OF THE INVENTION  
       [0028]    Referring to the Figures, there is shown one embodiment of a prior art sawhorse, and three embodiments of the invented sawhorse  10 ,  10 ′,  10 ″. In FIGS.  1 - 3 , there is shown a one-platform sawhorse  10  with first leg frame  12  and second leg frame  14  pivotally connected at a single axis  60 . First leg frame  12  is made of top member or top pipe  16 , right and left side members or pipes  18 ,  20  which are welded or otherwise attached at their top ends to top pipe  16  at connections  22 . The bottom ends of the right and left pipes are welded or otherwise attached to a transverse bottom pipe  26  at the outer ends of the pipe  26  at connections  30 . The bottom surface  34  of bottom pipe  26  is preferably a smooth, continuous surface substantially all the way across the width W of the sawhorse. Preferably, this bottom surface  34  is the rounded, cylindrical surface of the cylindrical bottom pipe  26 . Preferably, there are no feet or other protrusions from the bottom surface  34  at any location that would touch the ground G or other surface on which the sawhorse sets in the unfolded, and even the folded, positions.  
         [0029]    Preferably the first leg frame  12  is rigidly and non-pivotally connected to the top platform  40 , with the platform  40  being attached to top pipe  16  such that its top surface  42  is an a slight angle relative to level (horizontal) when the sawhorse is folded and positioned vertically. (FIG. 2). The angle is determined by the relative length of the first leg frame  12  and the second leg frame  14 , as discussed below, and angle (A) when the sawhorse is setup. The angle of the platform top surface  42  relative to the plane of the first leg frame  12  is set so that, when the sawhorse is unfolded, as in FIG. 3, the top surface  42  is level. Thus, one may see that a typical angle, but not the only operable one, is about 20-25 degrees from horizontal in FIG. 2.  
         [0030]    The second leg frame  14  has a shorter length L 2  than the length L 1  of the first leg frame  12 . The second leg frame  14  is preferably made of a right and left side pipe  48  and  50  that are welded, integrally, or otherwise attached to pivoting sleeves  52  with interior hollow spaces that pivotally receive the top pipe  16 . The bottom ends of the right and left side pipes  48  and  50  are welded or otherwise attached to a bottom member or pipe  56  that is parallel to pipe  26  and pipe  16  and platform  40 . As with the first leg frame  12  bottom pipe bottom surface  34 , pipe  56  has a bottom surface  58 , that is, the entire portion of the pipe  56  that touches the ground when unfolded that is smooth, broad, and free of downward or other protrusions that would catch or dig into the ground.  
         [0031]    Preferably, the generally rectangular leg frame  12  is four-sided, with the top side (top pipe  16  with platform  40 ) pivotally receiving the second leg frame. Preferably, the generally rectangular leg frame  14  is three-sided and attached at its top end (for example, the top ends of its legs) to the first leg frame  12 . Second leg frame  14  may also include transverse member  66  or other non-transverse members for strengthening. Second leg frame  14  is also narrower than first leg frame  12 , and generally rectangular, as is leg frame  12 . Therefore, with this system, one may see that the second leg frame  14  may pivot to a folded position, in which the generally rectangular leg frame  14  fits inside the first leg frame  14  and is coplanar with the first leg frame. Also, the second leg frame  14  pivots out to the position in FIG. 3, in which, being the shorter leg frame, it causes the pivot axis  60  to not be centered over the bottom pipes of the leg frames but shifted to the right in FIG. 3. In other words, the pivot axis  60  and platform  40  are not equidistant from the bottoms of the two leg frames, and are not equidistant to the vertical planes passing up through the bottom pipes. Still, the top surface  42  is level because of the special slanting attachment of the platform  40 . Preferably, the platform does not and need not pivot or move relative to first leg frame  12 .  
         [0032]    A chain  62  or other strong, secure limit or lock mechanism may be used to limit the amount of pivot of the leg frames relative to each other. This limit or lock may take the form of a connector between the two leg frames (such as chain  62 ) or, less preferably, may be a feature incorporated into the pivot mechanism that limits the amount of pivot of the leg frames relative to each other. Optionally, the limit or lock mechanism may lock the sawhorse, so that the leg frames will not pivot toward each other during use, unless the user purposely unlatches/unlocks the mechanism. Because the weight of objects on the sawhorse during use will tend to keep the sawhorse from collapsing, the preferred lock or limit does not need to make the sawhorse nonpivoting.  
         [0033]    A stop  67  is preferably included to limit movement of leg frame  14  relative to leg frame  12 , when the sawhorse is collapsed. Stop  67  prevents second leg frame  14  [does not] from swinging all the way through the first leg frame, but instead stops in the plane of the first leg frame  12 . Stop  67  may protrude up from bottom pipe  26  at an outer side of the pipe  26 , so that second leg frame hits, and is limited from further movement past, the stop  67  when the sawhorse is collapsed.  
         [0034]    In the preferred embodiment, both stop  67  and chain  62  serve to control the pivoting of the leg frames relative to each other. Without stop  67  and chain  62 , second leg frame (given the preferred connection by slidable/rotatable sleeve  52 ) would swing 360 degrees relative to the first leg frame around the sawhorse&#39;s single axis.  
         [0035]    Preferably, the various pipes/legs/transverse members are cylindrical and straight, but other members may be used, as long as their strength and lightness are appropriate, and as long as the surfaces  34 ,  58  are smooth, broad, long; straight, and non-biting into the support surface. The smooth, wide bottom surfaces  34  and  58  create an easily-movable sawhorse  10  that does not sink into the ground G and tends to slide smoothly along the support surface (G) when the user purposely moves it. This is beneficial to workiman, mechanics, and other users, as described in the Summary. While welding or other attachment means may be used, the various transverse members and vertical members may be formed in part or entirely by bending of pipe.  
         [0036]    Another embodiment is shown in FIGS.  4 - 6 , which includes a plurality of platforms. This sawhorse  10 ′ is preferably built like the one described in FIGS.  1 - 3 , but it includes an additional platform  70  on second leg frame  14 . Second platform  70  is transverse, that is, perpendicular to the right and left side pipes  48 ,  50 , and is preferably rigidly connected to the transverse member  66  so that its flat upper surface  72  is horizontal when the sawhorse is setup. Second platform  70  fits preferably between pipes  48 ,  50  and is shorter than the width of the open space “O”. In FIGS. 5 and 6, one may see an embodiment in which the second platform  70  is connected to the second, shorter leg frame, and has a top surface that is at an angle non-normal and non-parallel to the second leg frame plane and that is non-parallel to the top surface of the first platform. The second platform top surface is at an angle of approximately 30-35 degree relative to the first (top) platform surface, or typically within a range of about 25-40 degrees depending upon the preferred geometry of the relative lengths of the first leg frame and second leg frame and the angle of the leg frames when opened. Alternatively, the second platform may take the place of the rigidizing/reinforcing transverse pipe  66 , rather than being attached to the pipe  66 .  
         [0037]    To provide for the upper surface  72  being level when the sawhorse is unfolded, as in FIG. 6, the second platform  70  is attached to the member  66  so that its plane is at an angle slightly off from perpendicular to the plane of the second leg frame  14 . In other words, the second platform is slanted in an opposite direction to the first platform, as may be seen in FIG. 5, and the two angles of the first platform  40  and the second platform  70  may be calculated by geometry calculations based on the angle of the first leg frame and second leg frame when in the unfolded position and the relative lengths of the first leg frame and second leg frame.  
         [0038]    The platform(s) may be attached to the sawhorses by conventional fasteners. For example, nut and bolt and lock washer combinations may be used at several places along the length of the platforms to attach the platforms to the top pipe  16  and the transverse member  66 . The bolts (not shown) may pass all the way through the pipe  16  and member  66  in positions that do not interfere with the use and movement of the sawhorse.  
         [0039]    One may note that top platform  40  is attached to top pipe  16  in such a way that it does not significantly interfere with the pivoting of the two leg frames relative to each other. For example, there may be one or more washers or other spacers (not shown) placed between the top pipe  16  and the platform  40 , for example, at locations  72  to create a slight distance between the pipe  16  and the platform  40  to leave room for pivoting of the sleeves  52  on the pipe  16 . These spacers may be washers used on bolts that attach the platform to the pipe  16 , for example.  
         [0040]    Optionally, as illustrated in FIG. 7, each of the leg frame ( 12 ,  14 ) of an alternative sawhorse  10 ″ may include a telescoping feature, to lengthen and shorten the leg frames. Such a feature allows the sawhorse to, in effect, be made taller or shorter, to adjust the height of the platform(s), preferably with both leg frames being adjusted to maintain the top platform level with horizontal. The feature may include telescoping structure  80  on each vertical pipe ( 18 ,  20 ,  48 ,  50 ), wherein the lower portion  82  of the first leg frame slides toward and away from the upper portion  84  of the first leg frame. Also, the lower portion  86  of the second leg frame slides toward and away from the upper portion  88  of the second leg frame. A securement system  90  is included preferably on each pipe ( 18 ,  20 ,  48 ,  50 ) to firmly and surely anchor the portions of the leg frames to each other once their height has been selected.  
         [0041]    Various systems may be used for connecting the various pipe/members together in various embodiments of the invention. An especially-preferred connection system for connecting transverse member  66  to the second leg frame features adjustable connection of both ends of the transverse member  66  to the leg frame. Adjustability may either be incremental, or, preferably, continuous vertically up and down the leg frame. As illustrated in FIGS. 8 a  and  8   b , the transverse member may be connected to the vertical pipes  48  and  50  (one end of the transverse member and pipe  48  only are shown in FIGS. 8 a  and  8   b ) by means of a movable/removable clamp system  90 . The clamp system  90  on each end of member  66  may comprise two brace members  92 ,  92 ′ that each have a first portion  93  that extends circumferentially around its vertical pipe  48 ,  50  and a second portion  95  that extends inward horizontally and axially along a length of the transverse member  66 . The first and second portions are curved appropriately to approximately match the radius of the pipe and the radius of the transverse member  66 , and are sized so that the brace members  92 ,  92 ′ come near to each other but do not reach other when tightened around the pipe and transverse member. Thus, by tightening the two brace members together, for example, by bolt  97 , the brace members clamp around the transverse member  66  and the pipe  48 ,  50  to securely hold the member  66  at the desired height relative to the top pipe and the bottom members. Then, if desired, the user may loosen the bolt  97  to loosen the brace members  92 ,  92 ′ for adjusting the transverse member (in the clamp system  90 ) up or down on the second leg frame, and then the user may re-tighten the clamp system. In addition, there may be set screws  98  installed through the first portion  93  and the second portion  95  to further secure the brace member(s) to the vertical pipes and the transverse members and prevent vertical shifting of the vertical pipe relative to the clamp or horizontal shifting of the transverse member relative to the clamp.  
         [0042]    Although this invention has been described above with reference to particular means, materials and embodiments, it is to be understood that the invention is not limited to these disclosed particulars, but extends instead to all equivalents within the broad scope of this description.