1. Field of the Invention
The present invention relates to the field of stretcher bar framing and canvas fastening for art canvases. More particularly this is a unique stretcher bar system using interchangeable bar segments allowing for lengthening or shortening of the sides of the frame. It features a snap fit mechanism for easy assembly or disassembly of the frame. The canvas fastener system also provides for easy mounting, re-stretching, removal, and remounting of canvas.
2. The Prior Art
In the field of art, canvas paintings are traditionally mounted to a wooden frame comprised of wooden sections referred to as stretcher bars that provide a taunt support for the stretched canvas. The stretcher bar wooden sections are assembled by means of interlocking dove-tail edges wedged together to form corner. Wooden tightening wedges are used to adjust corners to produce a perfect square. Cross braces are sometimes used as a stabilizing tension brace. Canvas or other material is stretched around and over the front perimeter of the stretcher bars and affixed to the back side by conventional means using staples or nails.
In general, current commercially known wooden stretcher bars are made in fixed sizes and frames and cannot to be customized in length and width. Several other limitations of the wooden stretcher bars include warping, difficulty in forming exact corners, and the affordability of museum depth stretcher bars. A limited number of adjustable stretcher bar frames that expand or contract in some manner are known. These adjustable frames have various limitations and are difficult to use. U.S. Pat. No. 4,519,151 discloses a hollow tubular metallic frame coupled together at the end by a co-acting pair of corner elements. The frame size can be selectively expanded and contracted by a series of five different lengths of tubular frame elements providing a means to attach fabric along the tubular edges by inserting pins in openings in the frame members. However, the disadvantage of this design is its limitation in dimension. In addition, round tubes cannot be framed and are not generally used in the field of art or accepted by galleries. U.S. Pat. No. 4,144,660 discloses an adjustable canvas stretching frame of separate, interchangeable, uniform frame segments which can be interconnected to form a limited number of size small rectangular or square frames. The primary feature of this device is to provide a means to maintain an overall rectangular shape of the frame, adjust gaps between adjacent segments of the frame, and to provide a taut surface by adjusting the tension in frame segments, with respect to each other, so a canvas can be re-stretched without damaging the canvas and/or removing the canvas from the frame. Several shortcomings to this mechanically complex design include its numerous parts and special hardware required for its assembly. Also, it does not allow for the canvas to be easily removed and reused. U.S. Pat. No. 6,675,510 discloses a lateral and longitudinal mechanized edge gripping method to avoid uneven stresses, distortion, corner wrinkles, and tearing of canvas. It primarily allows for removal and remounting of the canvas but the disadvantage is that its difficulty to evenly stretch canvas due to interference from and canvas grippers. Additional and various other prior art is also cited in U.S. Pat. No. 4,144,660, U.S. Pat. No. 4,519,151, and U.S. Pat. No. 6,675,510, and is incorporated herein by reference.
The above framing and stretching canvas references are primarily for attaching or remounting of canvas and do not allow for modifications in the overall size of the frame. The prior art does not provide the capability or means without prior training, skill, experience, or strength for quick and to easily assembly/disassembly, lengthening/shortening the stretcher bar to other frame configurations. The prior art does not allow for the stretcher bar to be easily dismantled for compact storage and for less costly transport. It also does not address the need for affordable museum quality stretcher bars.
The object of the present invention is to provide a quick and easy system to construct a frame using stretcher bar segments that are interconnected and interchangeable so that an artist can use any number of separate stretcher bar segments for any size without the need for custom made canvas frames. This system utilizes a combination of incremental length stretcher bar segments and pre-molded fixed length corner segments that allow for exact square corners without the need for adjustment. The side bar and corner segments effortlessly snap together and interlock to form an array of stretcher bar lengths. The snap fit interlocking side bar and corner segments feature both a male plug member end and a female socket member end along with a quick side-release locking mechanism.
The interior of each side bar and corner segment has a guide bar and a pair of flexible latching arms extending distally from the plug base. Each arm has a latching notch adjacent to the flat tooth surface that aligns and latches to a corresponding engagement shoulder on each side wall of the socket cavity along a center longitudinal outer axis. When the plug is fully inserted into the socket cavity, each notched flat tooth arm flexes back to its original relaxed position while the flat tooth surface extends through the open portion of the side apertures to connect and interlock the plug and socket to adjacent side bar or corner segments. Side bar and corner segments snap together and additional side bars can be added until the desired length and width of the stretcher bar frame is constructed. Each flat tooth surface fits into a corresponding aperture to evenly match the surface of the side bar and corner segments preventing indentations on the outer sides of the stretcher bar.
The inside of the side bar and corner segment has a plug guide that extends distally from the plug base and four corresponding socket cavity guides along the center longitudinal axis to direct and support the connecting side bars or corner segments. Each side bar and corner segment has an extended base on the plug side and corresponding lip along the open socket side to further secure and side bar or corner segments for a tight and straight fit.
A side-release mechanism is formed at each side wall aperture opening from the socket cavity through a portion of the outer and inside side segment walls once the plug is fully inserted into the socket. Each aperture has a single angular proximal edge engagement shoulder that cooperates and engages with a latching arm notch located on each flexible flat headed latching arm to retain and interlock the plug within the socket. Each aperture opening enables access to the plug flexible flat headed latching arms from the exterior of the socket to allow for release of a connecting side bar or corner segment. A stretcher bar frame can also be quickly disassembled, reconfigured, or stored by separating the plug and socket members. By concurrently pressing on the side-release flat tooth surfaces on each side of a side bar or corner segments, this forces each flexible internal arm to flex inward towards the center of the cavity until the flexible flat headed latching arm notch and engagement shoulder edges disengage and clear the socket proximal edge engagement shoulder to release the adjacent segment.
A further objective of this invention is to provide an easy means to fasten a canvas to the stretcher bar frame. A self healing fastening block consisting of flexible polyurethane, a resilient polyolefin, or a similar functional type material allows tack fasteners or staples to secure the canvas to the frame. The tack fasteners and staples are capable of being inserted through single or multiple layers of canvas. The penetration of the tack fasteners/staples allow for a secure holding of the canvas to the fastening block on the back side of the stretcher bar and corner segment. The durable self-healing block allows the canvas to be mounted/re-mounted stretched/re-stretched, repeatedly without damage to the frame or canvas.
The stretcher bar side and corner segments are preferably made of a low cost, light-weight, non-warping, durable plastic, resin, or any suitable material known in the art for molding or machining that provides structural durability, resiliency, and stability.
The stretcher bar dimensions follow the specifications of museum quality depth stretcher bars. (The depth is not limited to museum profiles and includes traditional and gallery depths as well.) The museum profile does not require the need for additional framing of the art work
The accompanying drawings are included to provide a further understand of the invention, and are incorporated in and constitute a part of this specification. The drawings illustrate embodiments of the invention and, together with the description, serve to explain the principles of the invention.
The present invention relates to a novel and unique stretcher bar framing and canvas fastening system that comprises of a plurality of individual interchangeable, interconnecting (snapping together), side bar and corner segments. The stretcher bar framing system allows the user to assemble a broad range of square and rectangular shaped frames. This is accomplished by adding or removing side bar segments along the periphery within the four corner segments to lengthen or shorten the length and width of the stretcher bar. As noted above,
After assembling the two side bars segments 2, 3 and the four corner segments 4, 5, 6, and 7 to form a stretcher bar 1.
The four right angle corner segments 4, 5, 6, and 7, are pre-molded and of a fixed outer length that allow for an exact square corner without the need for adjustable corner braces or a stabilizing tension brace.
The outside length of each corner segment depicted in
Side bar and corner segments can be combined to assemble side lengths and widths ranging from 24 inches to 72 inches and various common size stretcher bar lengths in between. For illustrative purposes only, the number and lengths of the side bar segments and corner segments required to assembly a range of stretcher bar frame from 24×24 inches to 72×72 inches is listed below.
The overall dimensional length and width of the stretcher bar frame is not limited to 72 inches. Larger stretcher bar frames can be assembled by adding additional 6 and 12 inch side bar segments. Furthermore, with the addition and combination of 1, 2 and 4 inch side bar segments, all one inch incremental lengths and width between 24 inches to 72 inches can be assembled. The length of side bar segments and corner segments are not limited to inches and can be in other measurement units (metric). This stretcher bar framing and fastening system device for artist canvases is a significant advance in art framing.
A side-release mechanism is formed at each side wall through the open aperture 10 and 12 by extending an opening from the socket 9 of cavity 16 through a portion of the outer side wall 11 and inside side wall 13. Each aperture 10, 12 has a single angular proximal edge engagement shoulder 32 that cooperates with the plug 8 notch 27 to retain and interlock the plug 8 within the socket 9 cavity 16. The open apertures 10 and 12 also enable access to the plug 8 notch arms 29 from the exterior of the socket 9 to allow for quick release of connecting side bars from side bars or corner segments, or corner segments from corner segments. The particular size, shape, and location of the open aperture 10 and 12 can deviate as long as the side-release mechanism functions fundamentally as described herein.
To facilitate in guiding and align the plug 8 as it is inserted into the cavity 16 of the socket 9, a projecting plug guide bar 22 extends distally along the center longitudinal axis from the plug base 21 toward the adjacent side 15 of each side bar and corner segment for added strength in the stretcher bar frame. Projecting downward from the top cavity wall 17 and upward from the bottom cavity wall 18 are a top pair and bottom pair of projecting guides 23 that extend from the open end of the socket 9 inward and toward the adjacent side 15. The side bar 2 has an extended base on the plug 8 side and corresponding lip 20 along the entire perimeter of the open socket 9 side to further secure and strengthen side bars and/or corner segments together for a tight and straight fit. The particular size, shape, and location of the projecting guides 23 and guide bar 22 can deviate as long as the guiding mechanism functions fundamentally as described herein.
To quickly and easily disassemble the plug 8 from the socket 9, each plug 8 flat tooth surface 26 are concurrently pressed inward forcing each flexible flat headed latching arm 24 inward until the plug 8 flat headed latching arm 24 notches 27 disengage and clears the socket 9 proximal edge engagement shoulders 32 and pulling the connecting side bar segment and corner segments apart. This process is continued until the stretcher bar is completely disassembled or until the user assembles another square or rectangular shape to form a frame. This procedure is also used to disengage adjoining side bar segments and adjoining corner segments.
In this embodiment, the side view of each stretcher bar segment socket side 9 shows an extended outside front canvas corner 33, an angular front-side surface 34 which gradually slope downward between the outside wall 11 and the inside wall 13, and a front side surface wall 35. The extended outside canvas corner surface is integrated into each stretcher bar segment to provide a supporting rim edge around the stretcher bar frame perimeter to support canvases or other material. Adjacent extended outside front canvas corner 33 is an angular front-side surface 34 that slopes downward from the extended outside front canvas corner 33, to the larger front side surface 35 that is designed to allow the main body of the stretcher bar frame surface to remain flat and without indentation after a canvas has been fastened. The extended outside front canvas corner 33, around the stretcher bar frame perimeter serves to reduce adherence to the stretcher bar thus allowing avoidance of leaching paint or oils through a canvas.
In the middle of the bar segment socket side 9 is a substantially rectangular shaped interior cavity 16. The cavity 16 encompasses the area between an internal top cavity wall 17, an opposing bottom cavity wall 18, and a pair of side cavity walls 19, each of which connects the top wall to the bottom wall at the side edges. As previously stated, the cavity 16 allows the insertion of flexible flat headed latching arms and a guide bar to connect and interlock stretcher bar segments.
The specifications and drawings of this invention may be embodied and practices in other specific forms and modification without departing from the spirit and essential characteristics thereof. The present embodiments therefore are considered in all respects as illustrative and not restrictive. The scope of the invention is indicated by the appended claims rather than by the foregoing description. All variations, substitutions, departures, and changes that come within the meaning and range of equivalency of the claims therefore are intended to be embraced therein.