CA2941551A1 - Canvas stretcher bar framing system with a built in ball slot canvas fastening system - Google Patents

Abstract

Disclosed is a Friction Fit Canvas Stretcher Bar Framing System with a combined built in Ball Slot Canvas Fastening System. It is specifically designed for Artists and for those who commercially produce picture frames and ready to hang art that has been done on canvas or a similar type of material. Designed for quick easy manual or automated mechanical mounting.
This unique interlocking friction fit framing and fastening system does not require any tools to assemble and it does not require any special skills or tools to properly stretch and attach canvas or similar type material onto a frame. Uniform, precision cut, interlocking, frame sections consisting of straight and curved sections, each with a protruding male end and a recessed female end connect together by aligning a male end over top of a corresponding sections female end and then pressing down. The male end slides into the female end to form a tight friction fit connection and a perfect 90 degree corner. Frame sections come in various standard stretcher bar lengths, widths, depths and profiles and can easily be assembled to form rectangular, square, round and oval shaped frames in an array of sizes. Canvas is evenly stretched and attached to a frame using a unique built in Ball Slot Fastening System and 2 rubber splines which are reusable and unlike staples, adhesives and clamps they are easy to install and uninstall and they do not cause any damage to the canvas or to the frame. Frame sections can easily be assembled and disassembled and canvas can be attached and detached for compact shipping and for repeated use.

Description

Description BACKGROUND OF THE INVENTION
Field of the invention. The present invention relates to the field of Stretcher Bar Framing and Canvas Stretching for art canvas and similar type material. More particularly this is a unique stretcher bar framing system and combined ball slot fastening system that does not require any tools or any canvas stretching or mounting experience to use. Precision cut, interchangeable frame sections press together to form tight friction fit connections and perfect 90 degree rigid corners. The combined unique Ball Slot canvas fastening system that is built into the back of each frame component allows for fast easy even stretching and mounting of canvas without tools and without causing any damage to the canvas or to the stretcher bar frame. Both the framing system and the fastening system can be assembled and disassembled repeatedly without damage. The uniformity of the friction fit framing system and the uniformity of the combined built in ball slot canvas mounting system allows for quick easy manual mounting and fully automated mechanical mounting.

- 2 -Prior Art In the field of art, canvas paintings are traditionally attached to a wooden frame comprised of wooden sections commonly referred to as stretcher bars that provide support for stretched canvas. Stretcher bar sections are assembled by means of interlocking dove tail ends wedged together to form a corner. Canvas or similar type material is stretched around and over the front of the stretcher bars using special canvas pliers and then attached to the back side of the frame by using staples or nails. Final tension to the canvas is achieved by inserting wood wedges into the corners of the frame and driving them in. Because of it's simplicity and low cost to manufacture this early 1930 prior art US1870492A has become the industry standard. Some of the known challenges that arise with using this type of system is that it requires a knowledgeable and skilled person to be able to keep the frame square and warp free while stretching and stapling the canvas evenly around the back side of it. Due to it's design the corners of this frame system can not be fastened together in any way without rendering the wood wedge tensioning system useless. Keeping an unsecured frame square while stretching canvas over it can be time consuming and frustrating. If a mistake is made while stapling the canvas to the frame, the staples have to be pulled out further damaging the canvas and the frame and the process is started over.
Several inventions have come out since the earliest patented stretcher bar frame system. All of them have unique variations of achieving the same end result which is stretching and attaching canvas art to a frame. There are variations of stretcher bar frame components and how they go together and there are variations of attaching the canvas to the frame The commonality between past and current prior art is that they all require knowledge and skill to properly stretch and mount canvas evenly. They all require tools and or fasteners to assemble a frame and or to stretch and mount the canvas and they all use some sort of stapling, clamping or adhesives to fasten the canvas to a frame which causes damage to the canvas and or to the frame. None of them are uniformly designed for fully automated mechanical mounting.
The present invention addresses and overcomes the shortcomings of all known prior art.

- 3 -SUMMARY OF THE INVENTION
The object of the present invention is to provide a simple, quick and easy to use system to manually or mechanically mount canvas art to a stretcher bar frame. The entire system utilizes uniform precision cut, interlocking stretcher bars consisting of straight and curved sections, each with a protruding male end and a recessed female end. Four sections are joined together to form a frame. Sections are joined together by aligning the male end of one section over top of another sections female end and then applying downward pressure the male end slides down into the female opening to form a tight friction fit connection and a perfect 90 degree rigid corner. Frame sections come in various standard stretcher bar lengths, widths, depths and profiles and they can easily be assembled to form rectangular, square, round and oval shaped frames in an array of sizes. Cross bar sections are provided for support in larger frames and are attached to the frame using the same joining method to form a tight friction fit connection.
Canvas is evenly stretched over the frame and attached to the back using a unique built in Ball Slot Canvas Fastening System which consists of 2 parallel ball slots that run down the back side of every section and 2 rubber splines which are used to evenly stretch and fasten the canvas to the back side of the frame. Unlike staples, adhesives and clamps rubber splines are easy to install and uninstall and they do not cause any damage to the canvas or to the frame. Canvas can easily be attached and detached without damage and frame sections can easily be assembled and disassembled for repeated use.

- 4 -BRIEF DESCRIPTION OF THE DRAWINGS
The accompanying drawings are included to provide a further understanding 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 and summary of the invention serve to explain the principles of the invention.
FIG.1-1 is a top view of a typical straight stretcher bar section.
FIG.1-2 is a top view of a protruding male end on a typical straight stretcher bar section.
FIG.1-3 is a top view of a recessed female end on a typical straight stretcher bar section.
FIG.2 is a top view of the parallel ball slots that are located on the back side of a typical stretcher bar section.
FIG.3 is a view of a cross section view of a typical stretcher bar section.
FIG.3-1 is a cross section view of the first ball slot that along with the spline holds the canvas in position and applies pre tension.
FIG.3-2 is a cross section view of the second ball slot that along with the spline locks the canvas in position and applies even final tension.
FIG.4 is a top view of an assembled rectangle frame with cross supports.
FIG.4-1 is a top view of a connected typical straight stretcher bar section that is used for large frames.
FIG.4-2 is a top view of a connected typical straight stretcher bar section that has a recessed female socket centered in the middle of the stretcher bar to accept a cross bar support.
FIG.4-3 is a top view of a typical horizontal cross bar section that has two male ends.
FIG.4-4 is a top view of a typical vertical cross bar section that has two male ends and two recessed female sockets centered in the middle of the bar.
FIG.5 is a top view of the back of an assembled rectangle frame that shows the two parallel ball slots.
FIG.6 is a top view of an assembled round frame with cross supports.
FIG.6-1 is a top view of a typical curved stretcher bar section.
FIG.6-2 is a top view of a protruding male end on a typical curved stretcher bar section.
FIG.6-3 is a top view of a recessed female end on a typical curved stretcher bar section.
FIG.6-4 is a top view of a typical horizontal cross bar section in a round frame that has two male ends.
FIG.6-5 is a top view of a typical vertical cross bar section in a round frame that has two male ends and two recessed female sockets centered in the middle of the bar.
FIG.7 is a top view of the back of an assembled round frame that shows the two parallel ball slots.
FIG.8 shows step one in attaching the canvas to the frame. It is a cross section view of a section of an assembled frame and it's upside down placement centered on top of the canvas (FIG.8-1).

- 5 -FIG.9 shows step two in attaching the canvas to the frame. It is a cross section view of the canvas wrapped around the frame and the placement of the spline (FIG.9-2) over ball slot number 1. (FIG.9-1) FIG.10 shows step three in attaching the canvas to the frame. It is a cross section view of the canvas wrapped around the frame and shows the pre tension spline 1 inserted down into ball slot one (FIG.10-1). It also shows the placement of spline 2 (FIG.10-2) over ball slot two (FIG.10-3).
FIG.11 shows step four in attaching the canvas to the frame. It is a cross section view of the canvas wrapped around the frame and shows the final tension spline 2 inserted into ball slot two (FIG.11-1).
FIG.12 is a cross section view of an assembled stretcher bar frame with the canvas installed.
FIG.13 is a cross section view of a normal picture frame with the canvas art installed utilising the unique Ball Slot Canvas Fastening System.

- 6 -DETAILED DESCRIPTION OF PREFERRED EMBODIMENT OF THE INVENTION
The present invention relates to a novel and unique friction fit stretcher bar framing system and novel and unique ball slot canvas fastening system. The friction fit stretcher bar frame system consists of precision cut frame sections (FIG.1) that can be made from wood, aluminum or plastic composites. Sections come in various standard stretcher bar lengths and in various widths, thicknesses and profiles. They come in straight lengths (FIG.1) for rectangle and square frames as well as curved sections (FIG.6-1) for round and oval frames. Each end of a straight section has been precision cut on a 45 degree angle and has a male end that protrudes from one end (Fig.1-2.) and a recessed female opening on the other end (FIG.1-3).
Each end of a curved section has been cut straight and has a male end that protrudes from one end (Fig.6-2.)and a female opening that is recessed on the other end (Fig.6-3.).
The back side of each section (FIG. 2) has 2 parallel ball slots (FIG. 2-1 and FIG. 2-2) also shown in cross section drawing (FIG. 3-1 and FIG. 3-2).
Frames are assembled by joining 4 sections (FIG. 1) together. In the case of a rectangle frame 2 plural sections of equal length are joined to 2 other plural sections that are equal in length.
Sections are joined together by lifting and a placing one section over another section and aligning the male end (FIG. 1-2) up to the female opening (FIG. 1-3) in the section underneath it and then applying downward pressure the male end is pressed into the lower female end forming a tight rigid friction fit 90 degree corner. The remaining sections are joined together in the same manner to form a closed rectangle frame. Cross sections (FIG.4-1, 4-2, 6-4 and 6-5) provide for extra support in larger frames.
Stretching and attaching canvas to the frame is done by first laying the canvas art face down on a flat surface. The assembled frame is then placed upside down (FIG.8.) and centered on top of the canvas. The canvas is then neatly wrapped around the outside of the frame (FIG. 9) and the corners are neatly folded. Starting at a corner and working your way around the frame, the canvas is gently pulled inward applying slight tension while pressing spline 1 (FIG. 9-2) into ball slot number one (FIG. 9-1). As the spline on top of the canvas is pushed down into the ball slot it compresses to fit into the slot pulling the canvas down with it. Once the spline contacts the bottom of the ball slot it re expands locking the canvas in place. Spline 1 and ball slot 1 holds the canvas evenly in place and applies pretension to the canvas (FIG. 10-1).
The second spline (FIG. 10-2) is then pressed into ball slot 2 (FIG. 10-3) to apply even final tension to the canvas (FIG. 11).
To remove the canvas simply find the ends of the splines and pull them upward to release the canvas. FIG. 12 shows a cross section view of an assembled stretcher bar frame with the canvas installed. FIG. 13 shows a cross section view of a common picture frame with the canvas installed on the back using The Ball Slot Canvas Fastening System.

- 7 -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.

Claims (13)

- 8 -

1. A stretcher bar framing and fastening system for stretching, re stretching, mounting, dismounting, attaching and detaching artist canvas comprising a plurality of precision cut, interlocking, interchangeable, variable lengths, side bar sections featuring a press together friction fit joining and connecting method utilizing a protruding male plug on one end and recessed female socket on the other end that interconnect to form an array of various sizes of square, rectangular, round and oval frames;
a female socket on one end having an open cavity, having side walls, which is open at the open end and closed at the adjacent end;
a male plug on the opposite end, having sidewalls for insertion through a corresponding sections top open end of said cavity of said female socket end;
a male plug end is fully inserted down into the open end of said cavity, to engage, mate and interlock said plug member to said female socket member;
a fastening ball slot on the back side of each side bar section to stretch, attach and secure canvas to said stretcher bar frame with a rubber spline and;
a stretcher bar front side surface, on all side bar sections, having an extending, protruding, rounded outside edge, which a canvas is stretched over, that slopes downward towards the front side surface.

2. The stretcher bar frame according to claim 1 wherein each side bar section has a protruding male plug and a recessed female socket positioned at opposite ends.

3. The stretcher bar frame according to claim 1 wherein the length and width can be increased or decreased by adding or removing side bar sections to form an array of various sizes of square, rectangular, round or oval frames.

4. The stretcher bar according to claim 1 wherein each section having a male plug end and female socket end being adapted to mate with and affix to an adjacent section when said plug end is pressed downward into a said socket end.

5. The stretcher bar according to claim 1 wherein said means for quickly decoupling and disassembling stretcher bar frame sections and canvas for storing, shipping or for repeated use.

6. A stretcher bar fastening system for mounting, stretching, attaching, removing and reattaching artist canvas comprising:
a plurality of friction fitting side bar sections featuring two parallel ball slots on the back side surface on each stretcher bar section for stretching, fastening and securing of said canvas.

7. The fastening system according to claim 6 wherein two parallel ball slots stretches and secures the said canvas around the perimeter of the said stretcher bar frame by inserting said rubber splines.

8. The fastening system according to claim 6 wherein one or more parallel ball slots stretches and secures art canvas or similar type art medium on to the back of a picture frame by inserting said rubber splines.

9. The fastening system according to claim 6 wherein a plurality of the said two parallel ball slots are configured on said exposed back side thereof, to provide access to said splines for purposes to mounting, remounting, stretching, re-stretching, or dismounting of canvas along four variable length edges.

10. The fastening system according to claim 6 wherein a plurality of ball slots are configured on said exposed back side thereof, to provide a receptacle for a plurality rubber splines to be uniformly in pairs, along each of the two edges that run substantially parallel to each along the corresponding length-wide edges.

11. The fastening system according to claim 6 wherein a plurality of said ball slots are configured on said exposed back side thereof, to provide access to said splines for purposes of adjusting and sustaining stretching tension of said canvas.

12. The fastening system according to claim 6 wherein a plurality of said ball slots are configured on said exposed back side thereof, to provide access to said splines for purposes of adjusting and correcting shifting and non-uniform distribution of tensional stress in a canvas.

13. The fastening system according to claim 6 wherein said ball slot provides a method of securing canvas, including in particular art canvas and similar type flexible art medium, onto stretcher bar frame using said rubber spline enabling easy removal of said canvas for storage and shipping.