Abstract:
A stretcher bar framing device having a narrow top surface, an interior surface, an exterior surface and an angled edge such that a stretched canvas touches only the top surface. The top surface provides a surface for supporting a painting canvas, reducing the surface area contacting the canvas and increasing the paintable surface. A bottom surface of the frame contains a channel so that the canvas material is folded over the top along an exterior surface and folded into a channel so that a rubber spline may be inserted attaching the canvas to the frame without the need for staples.

Description:
TECHNICAL FIELD 
     In general, this invention relates to a stretcher bar frame and more specifically, to an angled stretcher bar frame producing a minimal contact with a stretched canvas. 
     BACKGROUND OF THE INVENTION 
     In general, conventional frames have a flat framing structure profile. These conventional frames typically include a front surface whose area is defined by the thickness of the material used to construct the frame. In such frames, a more sturdy framing surface results in a thick front surface. 
     When a canvas or other material is mounted on a prior art frame, the material is stretched across the top surface with a tautness sufficient to allow an artist to paint on the material. Accordingly, prior art frames have a central portion in which there is no underlying structure supporting the material. As the material spreads outward toward the edge of the frame, it comes in contact with the front surface of the frame and eventually wraps around the perimeter of the frame. Where the top surface contacts the frame, the canvas is no longer taut, but becomes stiff. Typically, artists do not paint directly underneath the hard surface as there is a noticeable line where the canvas meets the edge of the frame. This is also true in mounting a picture on a similar frame as there will be a line where the frame meets the material being mounted. 
     After an artist&#39;s canvas is stretched across a flat profile frame, the canvas is typically fixed to the prior art frame by attaching staples alongside the edge. These staples can be awkward, unsightly or present a potential safety risk, as a user may be cut by the projecting staples. 
     Based on the above-mentioned deficiencies in the conventional framing structures, there is a need for a stretcher bar frame structure that increases the amount of usable canvas or mounting space by minimalizing the contact between the material mounted on a frame and the underlying framing structure. Additionally, there is a need for a stretcher bar framing structure that can have material attached to it without the need for staples or other fastening means. 
     SUMMARY OF THE INVENTION 
     The present invention satisfies the above-mentioned need by an angled stretcher bar frame having a profile to produce a minimal contact with a stretched canvas and with a channel in a bottom surface to secure the stretched canvas without requiring use of staples. 
     Generally, the present invention provides a stretcher bar frame. The frame includes a substantially vertical exterior surface, a substantially vertical interior surface, the interior surface substantially parallel to the exterior surface, a substantially horizontal top surface, the top surface abutting an upper portion of the exterior surface, and an angled surface, the angled surface coupled to the top surface and to an upper portion of the interior surface.. Additionally, the angled surface defines a profile of the frame, the profile angled such that the angled surface and the interior surface do not break a horizontal plane intersecting the top surface. 
     In another aspect of the present invention, a stretcher bar frame is provided. The stretcher bar frame includes a substantially horizontal top surface, the top surface having an interior edge and an exterior edge, an angled surface, the angled surface abutting the interior edge of the top surface, and angled downward relative to the top surface, and a sheet of material covering the top surface, and overlapping the exterior edge of the top surface. Moreover, the angled surface defines a profile of the frame, the profile angled such that the angled surface and the interior surface do not contact the material. 
     In a further aspect of the present invention, a stretcher bar frame is provided. The stretcher bar frame includes a top edge and an interior edge, wherein the top edge and the interior edge define an angled profile. The angled profile is angled such that only the top edge contacts a horizontal plane intersecting the top edge. 
     When utilizing the present invention in a painting, an artist typically paints solely on the stretched, taut canvas, not painting on any canvas portion that has a wood support directly underneath. Because the canvas surface is held taut solely at the top surface edges, and the angled portion does not touch the canvas in any way, the present invention increases the surface area in which an artist may effectively paint on a stretched canvas. 
    
    
     BRIEF DESCRIPTION OF THE DRAWING 
     Objects and features of the invention noted above are explained in more detail with reference to the figures, and in which like referenced numerals are use to indicate like parts in the various views: 
     FIG. 1 is a front elevational view of the prior art; 
     FIG. 2 is a side view of the prior art; 
     FIG. 3 is a front elevational view of the stretcher bar framing device of the present invention; 
     FIG. 4 is a back elevational view of the stretcher bar framing device of the present invention; 
     FIG. 5 is a side view of the stretcher bar framing device of the present invention; 
     FIG. 6 is a side view of the stretcher bar framing device of the present invention; 
     FIG. 7 is a side view of the stretcher bar framing device of the present invention. 
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
     For a better understanding of the present invention, reference may be had to the following detailed description taken in conjunction with the printed claims and accompanying drawings. 
     FIGS. 1 and 2 are representative of prior art framing devices, denoted generally by the numeral  10 . A typical prior art frame consists of multiple framing workpieces  12  which, as designated in a cross section in FIG. 2, are a rectangular flat pieces. As a canvas  14  is stretched over the workpieces  12 , the center of the canvas  14  is taut with nothing underneath. However, where the canvas meets the edge of the profile an indentation occurs, designated generally at  16 . This indentation  16  is caused by the pressure of the end of the workpiece  12  on the taut canvas  14 . The canvas  14  is then secured to the frame  10  by use of staples  18 . 
     FIG. 3 is a front elevational view of the stretcher bar framing device of the present invention, denoted generally by the numeral  30 . The stretcher bar framing device  30  is composed of multiple workpieces having matching surface structures. The shape of the stretcher bar frame  30  is defined by exterior surface  32 . In the preferred embodiment, the shape of the frame  30  is a rectangle entailing two sets of opposite facing workpieces. As would be understood by anyone skilled in the relevant art, different shaped framing structures are included within the scope of the present invention and would require a different number of external surfaces and/or different configuration of those surfaces. Such other configurations include varied geometric shapes such as octagons, triangles, circles and squares or could include outlines of objects such as a star or a helmet. 
     FIGS. 5,  6  and  7  denote different embodiments and dimensions of the stretcher bar framing device of the present invention. As best seen in the side view, each workpiece has a top surface  34  which defines a narrow edge around the perimeter of the frame. The top surface  34  is adjacent external surface  32  and provides a minimal horizontal surface. It will be understood that top surface  34  may be rounded or contoured to improve its use as a guide surface for a canvas. 
     The stretcher bar framing device  30  also has an interior surface  36  which is parallel to exterior surface  32 . As noted in the three different embodiments, the ratio of the height of the exterior surface  32  to the height of the interior surface  36  may vary. However, the height of interior surface  36  will always be less than the height of exterior surface  32 . 
     Top surface  34  is connected to interior surface  36  by angled surface  38 . Angled surface  38  defines the profile of the stretcher bar framing device  30 . As can be seen in the different embodiments, the angle of the profile varies, but the angle is sufficient so that no part of angle surface  38  contacts a horizontal plane intersecting top surface  34 . Because interior surface  36  and angled surface  38  are always at a lesser height than top surface  34 , top surface  34  defines the tallest point of stretcher bar framing device  30 . 
     FIG. 4 is a back elevational view of the stretcher bar framing device of the present invention. The stretcher bar framing device  30  has a bottom surface  50  which is opposite of angled surface  38 . The thickness of bottom surface  50  is the distance between interior surface  36  and exterior surface  32 . Bottom surface  50  is generally planer and provides a flat bottom for the framing device  30 . Located on the face of bottom surface  50  is channel  48  which generally runs parallel to interior surface  36  and exterior surface  32 . The channel  48  can be of a varied depth and will typically not be greater than the height of interior surface  36 . 
     The framing device  30  is assembled by compiling workpieces having matching exterior surface  32 , interior surface  36 , angled surface  38 , top surface  34 , bottom surface  50  and channel  48 . The workpieces are constructed of wood in the preferred embodiment, but it is within the scope of the present invention to have substitute suitable framing material such as plastics and metals. The workpieces are arranged so that they form the desired shape of the frame. In the preferred embodiment, there are two longer workpieces facing opposite of each other connected by two shorter workpieces also facing opposite each other, the four forming rectangle. For this shape, the workpieces are cut with the 45 degree mitred cut  42  such that the assembled workpieces form right angles. Other embodiments utilizing different configurations, such as triangle would use a different mitred cut, such as a 30 and a 60 degree angle. The workpieces may be joined by any typical wood joining method such as the application of adhesive, the use of nails or screws or the insertion of a staple. 
     Once the framing structure  30  is assembled, a sheet of artist canvas or other suitable material for framing  40  is draped over the surface and stretched so that it is solely touching the top surface edge  34  and is taut in the middle. As can be seen in FIG. 3, there is no longer an indentation line as in the prior art. The canvas  40  is draped over top surface  34 , folded along exterior surface  32  and folded under bottom surface  50  with the excess material folded into channel  48 . After the material  40  has been stretched tightly and inserted into channel  48 , a rubber spline  46  is inserted into channel such that it holds the canvas to the frame as demonstrated in FIG.  6 . At this point, the attachment of the canvas to the frame may be reinforced by the use of additional staples (not shown), but they are not required. 
     As would be understood, different embodiments eliminating one or more of the surfaces is considered within the scope of the present invention. For example, an alternate embodiment could eliminate the use of the angled surface. However, the frame would still have the profile defined from the top surface to the interior surface as described in the present invention. Additionally, other embodiments could either remove the exterior or interior surfaces and still be within the scope of the present invention. 
     When utilizing the present invention in the painting, the artist typically paints solely on the stretched canvas  40 , not painting on any canvas portion that has a wood support directly underneath. Because the canvas surface  40  is held taut solely by top surface edges  34  and angled portion  38  does not touch the canvas  40  in any way, the present invention increases the surface area in which an artist may effectively paint on a stretched canvas  40 . 
     In the foregoing specification, the present invention has been described with reference to specific exemplary embodiments thereof. The invention is considered to have been described in such full, clear and concise terms as to enable a person or ordinary skill in the art to make and use the same. It will be apparent to those skilled in the art that a person understanding this invention may conceive of changes or other embodiments or variations, which utilize the principles of this invention without departing from the broader spirit and scope of the invention as set forth in dependent claims. All are considered within the sphere, spirit and scope of the invention. The specifications and drawings are, therefore, to be regarded in an illustrative rather than a restrictive sense. Accordingly, it is not intended that the invention be limited except as may be necessary in view of the pendant claims or their equivalents which particularly point out and distinctly claim the subject matter applicants regard as their invention.