Abstract:
A workbench for use with a workpiece includes a work surface having multiple slots therethrough for securing the workpiece thereto; a pair of spaced apart frames attached to the work surface, wherein each frame includes a pair of legs and a brace structure; wherein the legs each have a groove extending along the length thereof, and which further includes a leg extension adjustably received in the groove for individually and infinitely adjusting the length of each leg.

Description:
RELATED APPLICATIONS 
     This application claims priority from United States of America Provisional Patent Application Ser. No. 60/104,620, filed Oct. 16, 1998 for PORTABLE AND ADJUSTABLE WORKBENCH. 
    
    
     FIELD OF THE INVENTION 
     This invention relates to portable workpiece supports, and specifically to a portable workbench that is capable of holding a variety of work pieces thereto using conventional workpiece fixing instrumentalities. 
     BACKGROUND OF THE INVENTION 
     A number of portable workbenches are known. Perhaps one of the most well known portable workbenches is that manufactured by Black and Decker, Inc. under the Workmate® trademark. While such known workbenches are suitable for their intended purposes, they have certain shortcomings that are addressed by the workbench of the invention. 
     A simple planing beam has been used by oriental craftsmen for centuries. This device incorporates a triangular support at one end thereof, and allows the workpiece to rest on the floor or ground at the other end thereof. Because a three-point support will always conform to the grounding surface, problems of leveling are not present with this form of workbench. 
     A workbench is intended to provide a working surface for a task. Frequently, this requires that a workpiece be secured to the working surface of a workbench. Although a number of attachment schemes are known, such schemes generally incorporate fixed attachment points, and only allow for attachment of a workpiece to the upper surface of the workbench by a predetermined fixation method, such as clamps or dogs which are provided with the workbench. 
     U.S. Pat. No. 1,147,522, granted Jul. 20, 1915 to Loomis describes an adjustable workbench wherein one set ground-contacting legs rides on another set of legs which support a cross-piece, allowing the workbench to be adjusted for height and uneven surfaces. 
     U.S. Pat. No. 4,877,109, granted Oct. 31, 1989 to Welch et al. describes and adjustable sawhorse having a set of fixed, hollow legs and a set of adjustable legs which are received in the hollow legs, and are moveable at fixed increments. 
     U.S. Pat. No. 5,007,502, granted Apr. 16, 1991 to Shapiro describes a self-leveling saw horse wherein the leg length is fixed and the cross-piece is adjustable to remain parallel to the supporting surface. 
     A variety of sawhorse brackets are manufactured, including those manufactured by Crawford Products, Inc., of West Hanover, Mass., which brackets receive pre-cut leg elements in receptacles on the lower surface thereof, and wherein, in some models, a gap is present between a portion of a cross-piece support and the cross-piece. 
     SUMMARY OF THE INVENTION 
     A workbench for use with a workpiece includes a work surface having multiple slots therethrough for securing the workpiece thereto; a pair of spaced apart frames attached to the work surface, wherein each frame includes a pair of legs and a brace structure; wherein the legs each have a groove extending along the length thereof, and which further includes a leg extension adjustably received in the groove for individually and infinitely adjusting the length of each leg. 
     An object of the invention is to provide a workbench that allows a user to attach a workpiece to a work surface using conventional attachment devices. 
     Another object of the invention is to allow work pieces to be attached to the bottom surface of the work surface. 
     A further object of the invention is to provide a workbench which includes an integrally formed leveling mechanism. 
     Still another object of the invention is to provide a workbench which may be compacted for easy transportation and shipping. 
     Yet another object of the invention is to provide a workbench which is inexpensive to manufacture and is durable. 
     These and other objects and advantages of the invention will become more fully apparent as the description which follows is read in conjunction with the drawings. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     FIG. 1 is a perspective view of a workbench constructed according to the invention, with a shelf assembly thereof removed to show detail. 
     FIG. 2 is a side elevation of the workbench of FIG. 1, with one set of legs extended to conform to an uneven surface. 
     FIG. 3 is a median elevation taken generally along the line  3 — 3  of FIG.  1 . 
     FIG. 4 is a partial end elevation of the workbench of FIG. 1, showing an upper brace in greater detail. 
     FIG. 5 is a perspective view of the workbench, taken from the upper left side thereof, in an environmental setting. 
     FIG. 6 is a perspective view of the workbench, taken from the lower left side thereof, in an environmental setting. 
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT 
     Turning initially to FIGS. 1 and 2, a workbench constructed according to the invention is depicted generally at  10 . As previously noted, the workbench of the invention is adjustable to conform to uneven surfaces and accommodates a variety of workpiece holders. 
     Workbench  10  includes two frames  12 ,  14 , which support a work surface  16 , also referred to herein as work surface member  16 . Each frame includes two legs  18 ,  20 , leg extensions  22 ,  24 , an upper brace  26 , and a lower brace  28 . Legs  18 ,  20  of each frame are fixed at an optimum angle with respect to one another, such angle being between 24° and 44°, and joined by upper brace  26  and lower brace  28 , collectively referred to herein as a brace structure. Upper brace  26  and legs  18 ,  20  may be fastened together by suitable fasteners  19 , such as bolts with nuts, the pieces may be held together by adhesive, or the pieces may be integrally formed, as by molding. Where threaded fasteners are used, the nuts may lock into countersunk holes in the legs. Upper brace  26  may be formed as shown in FIG. 4, with a slot  27  on either vertical face to receive fastener  19  therein. Upper brace  26  has what is referred to herein as an inverted keystone configuration, and, in the preferred embodiment, is located slightly below the upper terminus of legs  18 ,  20 , such that a gap  29  occurs between upper brace  26  and the lower surface of work surface  16 . Lower brace  28  and legs  18 ,  20  may be fastened together with screws, or other suitable fasteners, or integrally formed. 
     Each leg has a groove  30  machined along the inside face thereof along the length thereof. A leg extension is received in each groove  30 . Each leg extension includes a slot  32  machined therethrough along the length thereof. The extensions are free to slide along the length of the grooves in the legs. A fastening mechanism  33 , such as bolts are placed through holes in the legs and pass also through the grooves in the extensions, and nuts, or wing nuts, attach to the bolts to fix the extension relative to the leg. The location of the bolts in the legs limit the amount each extension may slide relative to its associated leg, and also serve to fix the extension in place relative to its associated leg. In this way each leg is independently and infinitely adjustable, allowing workbench  10  to be used on all manner of uneven surfaces, such as stairs, hills, rough ground, broken floors, etc. 
     Work surface  16  is fixed to frames  12  and  14  by means of fasteners  17  which extend through fastening points in upper braces  26  and through work surface  16 . Diagonally extending braces  34 ,  36  extend between work surface  16  and frames  12 ,  14 , respectively, to provide further stability to workbench  10 . 
     A bracket assembly  38  is located below work surface  16 , and includes a transverse member  40 , which is fixed to standoffs  42 ,  44 , which are secured to the lower surface of work surface  16 . Bracket assembly  38  is attached to the work surface  16  and to the diagonal braces. The distance between transverse member  40  and the bottom of work surface  16  is such as to facilitate the holding of standard pipe clamps, shown in FIGS. 5 and 6 at  70 ,  72 , in position for use by the operator. In this way a clamping means is provided whereby the operator may temporarily attach a variety of items, such as workpiece  74 , as shown in FIG. 5, to the edges of the top member to perform any number of operations on them. 
     A shelf assembly  46  includes a shelf  48 , and mounting plates  50 ,  52 , which are attached to the bottom edges of the lower braces  28 . Shelf  48  includes two main shelf bottom elements  54 ,  56 , two outer edge supports  58 ,  60 , and a center divider  62 . The pieces are assembled and attached to the bottom edges of the lower braces of the frames by screws or other attachment means  63 . Center divider  62  defines a pair of compartments in shelf assembly  46 . The construction of shelf assembly  46  provides extra strength, shelf compartments to separate stored items, and permits workbench  10  to be packaged in a smaller bundle for sale and shipping. 
     The top member may have a series of stopped slots machined therethrough, such as slots  64 ,  66  and  68 , along the length thereof. These slots facilitate the attachment of a variety of items to the top member using common bolts and nuts, or other attachment means. Items such as bench machines, vises, table top accessories and other clamping means may be attached as may be other items, as determined by the user. Stops and forming jigs may be secured to work surface  16 , as may be a variety of power tools. 
     In the preferred embodiment, workbench  10  is constructed with wood legs. The other components of the workbench may also be constructed of wood, metal, or molded or formed polymers. The selection of wood for the legs is the result of attempts to form or machine polymer material with grooves  30  and slots  32  formed in the legs: wood is simply the easiest material to be so formed. 
     Thus, a workbench which is portable, adjustable in height, able to compensate for uneven surfaces, capable of many different clamping alternatives, allows many items to be temporarily or permanently mounted to it, and with storage means for tools and other items has been disclosed. It is further capable of being manufactured economically and sold to a user at a reasonable price. Although a preferred embodiment of the workbench of the invention has been disclosed, it will be appreciated that further modifications and variations may be made thereof without departing from the scope of the invention as defined in the appended claims.