Patent Publication Number: US-2006010729-A1

Title: Nail-free interchangeable canvas frame

Description:
CROSS-REFERENCE TO RELATED APPLICATION  
      This application claims the priority benefit of Taiwan application serial no. 93118243, filed on Jun. 24, 2004. All disclosure of the Taiwan application is incorporated herein by reference.  
     BACKGROUND OF THE INVENTION  
      1. Field of the Invention  
      The present invention relates to a nail-free interchangeable canvas frame. More particularly, the present invention relates to a nail-free interchangeable canvas frame used during a painting process.  
      2. Description of the Related Art  
      Generally, when a painter is working on a canvas, the canvas needs to be spread out and fixed on a frame.  FIG. 1  is a schematic diagram showing a canvas fixed on a conventional frame. Please refer to  FIG. 1 . The conventional canvas frame  100  comprises four wooden brackets  110 . Each bracket  110  is fixed by an iron plate, such that the frame  100  cannot be dissembled after installed. When the canvas  50  is to be fixed on the frame  100 , instruments such as canvas nippers (not shown) are used to spread the canvas  50  evenly on the frame  100 . Thereafter, nails  60  are used to nail down the edge of the canvas  50  in the rear of the frame  100 .  
      However, in case the size of the painting is large, a longer wooden bracket is required. The longer the wooden brackets, the higher the prices, and the more expensive the canvas frame. Since the brackets are fixed by nails and glues, they cannot be dismantled and reassembled to other brackets with different sizes. Also, as the canvas is fixed to the frame by nails which cannot be easily pried out, the frame and canvas can be damaged by the nails, and the canvas cannot be removed after the painting is completed. To remove the canvas from the frame forcibly would very likely damage the frame and the canvas. For an artwork of the painter&#39;s dedication and deliberation, the risk of damaging the painting must be avoided.  
      Besides, since a frame can only be used once, a new painting would not only require a new canvas, but a new frame as well. In addition, as the canvas is fixed on the frame, the canvas and the frame must be stored in one piece, which leads to a waste in storage space. Also, when fixing the canvas on the frame, appropriate strength and skills are required, and ordinary painters would have to entrust professionals to perform the task.  
      It is noted that when a painter draws on the canvas, each stroke of the paintbrush should work closely with the flexibility of the canvas, such that the strength and aesthetic of the stroke can be demonstrated. However, after the canvas is fixed on the frame for some period, the variations due to hot expansion, cold shrinkage or absorption of moisture would alter the texture of the canvas. As a result, in many cases, before an artwork is finished, the canvas has lost its flexibility and the painter could not wield the paintbrush at will. In such cases, the canvas and frame ensemble must be sent to the art supplier for re-stretching. This process not only consumes time and cost, but increases the risk of damaging the artwork.  
     SUMMARY OF THE INVENTION  
      Accordingly, at least one objective of the present invention is to provide a nail-free interchangeable canvas frame, for painters to fix the canvas on the frame by themselves and dissemble the canvas from the frame after finishing an artwork and to repeatedly use the frame.  
      To achieve these and other advantages and in accordance with the purpose of the invention, as embodied and broadly described herein, the invention provides a nail-free interchangeable canvas frame, suitable for fixing a canvas for users to work on the canvas. The nail-free interchangeable canvas frame in the present invention mainly comprises a plurality of brackets and a plurality of fixing parts. Each bracket comprises a front side and a corresponding rear side. Each bracket comprises a clasp structure. These brackets are connected to form a frame body. The canvas is disposed in the front side of the brackets that form the frame body. The periphery of the canvas is flipped and folded in the clasp structure. The fixing parts can fasten the periphery of the canvas to the clasp structure.  
      In an embodiment, the nail-free interchangeable canvas frame further comprises a plurality of corner connection parts, and any two of the brackets can be connected by one corner connection part. Each of the two ends of a bracket comprises a slot, for example, and each of the two ends of the corner connection parts is inserted into one slot. The corner connection parts are L-shaped metal plates, for example.  
      In addition, the nail-free interchangeable canvas frame further comprises a plurality of adjustable parts, and each bracket comprises at least one positioning structure. The two ends of each adjustable part is adapted to balance against the positioning structures respectively on two brackets, and stretch the canvas fastened on the frame by changing the length of the adjustable part.  
      Each adjustable part comprises a bolt and a nut, for example. The bolt has the thread of a screw. The nut is screwed to one end of the bolt. When the bolt screws in relation to the nut, the distance of two ends of the adjustable part is adjusted. The positioning structure can be a plurality of screws fastened on the bracket, or a plurality of positioning grooves, for example. The positioning structures are located in the inner edge of the frame body, for example.  
      In addition, one end of the adjustable part can be pivoted on the bracket, and another end thereof is adapted to balance against the positioning structure in another bracket in relation to the adjustable part, and stretch the canvas fastened on the frame body by the distance variation of two ends of the adjustable parts.  
      Also, the two ends of each bracket are symmetric in a 45 degree angle, for example. These clasp structures are a plurality of clasp grooves, for example, and the fixing parts are adapted to fasten the periphery of the canvas in the clasp grooves. The nail-free interchangeable canvas frame further comprises a plurality of connection rods, for example, by which the fixing parts are attached to the brackets. The fixing parts apply the connection rods to firmly fasten the periphery of the canvas to the clasp structure. The fixing parts can be clasp-type fixing parts, or clip-type fixing parts.  
      According, the nail-free interchangeable canvas frame of the present invention has many advantages. For example, the frame is simple to use, the frame can be dismantled, reassembled and repeatedly used, the storage space for the frame is saved and the flexibility of the canvas can be adjusted anytime.  
      It is to be understood that both the foregoing general description and the following detailed description are exemplary, and are intended to provide further explanation of the invention as claimed. 
    
    
     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, serve to explain the principles of the invention.  
       FIG. 1  is a schematic diagram of a canvas fixed on a conventional canvas frame.  
       FIG. 2  is a schematic diagram showing a structure of a nail-free interchangeable canvas frame according to an embodiment of the present invention.  
       FIG. 3  is a cross-sectional view of a combination of a bracket, fixing part and a canvas.  
       FIG. 4  is a schematic diagram of a corner connection part.  
       FIG. 5A  is a schematic diagram of an adjustable part.  
       FIG. 5B  is a schematic diagram of another adjustable part.  
       FIG. 6  is a partial view of another bracket.  
       FIG. 7  is a partial diagram of a nail-free interchangeable canvas frame according to another embodiment of the present invention.  
       FIG. 8  is a schematic diagram of a combination of another connection rod, fixing part and a bracket.  
    
    
     DESCRIPTION OF THE EMBODIMENTS  
      Reference will now be made in detail to the present embodiments of the invention, examples of which are illustrated in the accompanying drawings. Wherever possible, the same reference numbers are used in the drawings and the description to refer to the same or like parts.  
       FIG. 2  is a schematic diagram of a structure of a nail-free interchangeable canvas frame according to an embodiment of the present invention. Please refer to  FIG. 2 . The nail-free interchangeable canvas frame  200  is adapted for fixing a canvas (not shown) for users to work on a canvas. The nail-free interchangeable canvas frame  200  mainly comprises a plurality of brackets  210 , a plurality of corner connection parts  230 , and a plurality of fixing parts  250 . In addition, the nail-free interchangeable canvas frame  200  further comprises a plurality of adjustable parts  270 , for example.  
       FIG. 3  is a cross-sectional view of a combination of a bracket, a fixing part and a canvas. Please refer to  FIGS. 2 and 3 . Each bracket  210  is made of aluminum, for example, having the advantage of light weight and rigidity. Each of the two ends of the bracket  210  is in 45 degrees angle and is symmetric to each other, for example, such that the four brackets  210  can be connected and form a square frame body. Each bracket  210  has a front face S 1  and a corresponding rear side S 2 . Each bracket  210  has a clasp structure  212 , which is located on the rear side S 2  of the bracket  210 . Alternatively, the clasp structure  21   2  can be located on the side of the bracket  210  covered by the canvas  50 . The clasp structure  212  is a clasp groove, for example, and the fixing part  250  is adapted to fasten the periphery of the canvas  50  in the clasp structure  212 . The fixing part  250  can take the form of a clasp or a clip, for example.  
      Since the clasp structure  212  may comprise an acute angle structure  214  at the edge of the bracket  210 , when the canvas  50  winds around the acute angle structure  214  and is fastened by the fixing part  250 , the acute angle structure  214  can provide sufficient strength to the canvas  50  to prevent the canvas  50  from loosening. Also, on the joint surface of the clasp structure  212  and the fixing part  250  are a plurality of slight protruding parts  21   6 , for example, to enhance the grip of the canvas  50  and the bracket  210 . Further, on the joint surface of the front end of the fixing part  250  and the bracket  210  are a plurality of toothed structures  252 , for example. Therefore, when the fixing part  250  fastens the canvas  50  inside the clasp structure  202 , the force can be adjusted to determine the tightness between the fixing part  250  and the bracket  210 .  
      Note that in the nail-free interchangeable canvas frame  200  of the present invention, the canvas  50  is fastened between the fixing part  250  and the clasp structure  212 , so the canvas  50  is not damaged. Therefore, the integrity of the canvas  50  can be maintained, and the bracket  210  would not be damaged.  
      Please refer to  FIG. 3 . The edge of the front side S 1  of the bracket  210  is a protrusion part  218 , for example, so after the canvas  50  is fastened on the bracket  210 , the front side S 1  of the bracket  210  only touches the protrusion part  218 . Accordingly, even the edge of the canvas  50  can be kept suspended in air and not attached to the bracket  210  to affect the feel of each stroke.  
       FIG. 4  is a schematic drawing of a corner connection part. Please refer to  FIGS. 2, 3  and  4 . Each of the two ends of the corner connection part  230  respectively connects with two brackets  210  such that these brackets  210  connect and form a frame body  205 . Each of the two ends of the bracket  210  comprises a slot  220 , as shown in  FIG. 3 . Alternatively, the slots  220  of two ends of the bracket  210  can be of an interflow design, such that the weight of the bracket  210  can be reduced. The two ends of the corner connection part  230  are inserted into two slots of two brackets  210 . The corner connection part  230  is an L-shaped metal plate, for example, as shown in  FIG. 4 . When each bracket  210  is assembled, the corner connection part  230  is completely hidden inside two slots  220 , for example.  
       FIG. 5A  is a schematic diagram of an adjustable part.  FIG. 6  is a partial diagram of another bracket. Please refer to  FIGS. 2 and 5 A. Each bracket  210  comprises at least one positioning structure  222 , or two in the present embodiment. The positioning structure  222  comprises a plurality of screws  224  fastened on the bracket  210 , for example, as shown in  FIG. 2 . Alternatively, the positioning structure  222  can be positioning grooves  226  on the bracket  210 . As shown in  FIG. 6 , the location of the positioning structure  222  is in the inner edge of the frame body  205 , for example. The two ends of each adjustable part  270  balance against two positioning structures  222  near the juncture of two adjacent brackets  210 . When the length of the adjustable part  270  varies, the positioning structure  222  transmits the strength to each bracket  210  such that each bracket  210  expands outside and stretches the canvas  50  fastened on the frame body  205 . Therefore, when the user fixes another canvas  50  on the nail-free interchangeable canvas frame  200 , the tension of the canvas  50  can be kept proper by adjusting the length of the adjustable part  270 . Further, when the canvas  50  loses tension due to hot expansion, cold shrinkage or absorption of moisture, the adjustable part  270  can be adjusted anytime for the canvas  50  to have proper tension.  
      Please refer to  FIG. 5A . Each adjustable part  270  may comprise a bolt  272  and two nuts  274 . On the two sides of the bolt  272  are the thread of a spiral, and the middle part is designed as a hexagonal pillar for users to screw the bolt with instruments such as a wench. The two nuts  274  are screwed at two ends of the bolt  272 . Since the bolt  272  and the nuts  274  are assembled through the spiral threads, the direction of the spiral thread can be designed in a way that as the bolt  272  screws in relation to the nut  274 , the distance between two nuts  274  can be adjusted.  
       FIG. 5B  is a schematic diagram showing another adjustable part. Please refer to  FIGS. 2 and 5 B. One end of the adjustable part  270  can be pivoted on the bracket  210 , and another end thereof is adapted to balance against the positioning structure  222  on another bracket  210  to achieve the same purpose of stretching the canvas  50  fastened on the frame body  205 . In addition, as one end of the adjustable part  270  is pivoted on the bracket  210 , the adjustable part  270  and the bracket  210  need not be stored separately, which makes it more portable, and more unlikely to lose the small adjustable part  270 .  
      Also, if each bracket  210  only comprises one positioning structure  222 , the positioning structure  222  can be located in the center of the bracket  210 , and the two ends of two adjustable parts  270  share one positioning structure  222 .  
       FIG. 7  is a partial diagram of a nail-free interchangeable canvas frame according to another embodiment of the present invention.  FIG. 8  is a schematic diagram of a combination of another connection rod, canvas faxing part, and bracket. Please refer to  FIG. 7 . The nail-free interchangeable canvas frame  300  of the present embodiment is different from the previous embodiment in the addition of connection rods  260 , and in that the fixing part  250  is connected to the bracket  210  through a connection rod  260 . Therefore, when carrying the bracket  210 , the fixing part  250  needs not be carried, such that the nail-free interchangeable canvas frame  300  is more portable. In addition, since the size of the connection rod  260  are properly calculated, as the fixing part  250  connected to the connection rod  260  is pressed and fastened to the clasp structure  212 , the connection rod  260  would push the fixing part  250  such that the fixing part  250  firmly balance against the clasp structure  212  to avoid the canvas  50  between the fixing part  250  and bracket  210  from loosening.  
      Please refer to  FIG. 8 . The assembly method of the connection rod  260 , the fixing part  250  and the bracket  210  is not limited to the method shown is  FIG. 7 , but can be the method shown in  FIG. 8 . Naturally, the assembly method of the connection rod  260 , the fixing part  250  and the bracket  210  shown in  FIGS. 7 and 8  are only exemplary and does not limit the scope of the present invention.  
      Note that the nail-free interchangeable canvas frame in the present invention is a frame to directly fix the canvas thereon, or the co-called “inner frame” known to those skilled in the art, but not a frame to embellish and protect the painting during display, or the so-called “outer frame.” 
      In summary, in the nail-free interchangeable canvas frame of the present invention, since each bracket is connected by a corner connection part, and then the canvas is fastened on the bracket by the fixing part, the design is simple to use, and the dismantling of the frame is easy, so the canvas frame can be used repeatedly, and the assembly of the frame and the canvas can be determined by the user. At the same time, since the canvas can be easily taken out from the frame, the storage space would only be a space for the canvas, and additional space for the frame is not required. If the canvas frame is made of materials such as aluminum, the high cost of the wooden frame can be reduced, and the aluminum frame is not only environmentally friendly but has better rigidity. Also, with the combination of brackets of different sizes, a canvas frame of different sizes can be assembled. In addition, with the design of adjustable parts, the user can adjust the canvas flexibility according to his or her preference. Compared with the conventional canvas frame connected by wooden brackets, the nail-free interchangeable canvas frame of the present invention is more economical and convenient.  
      It will be apparent to those skilled in the art that various modifications and variations can be made to the structure of the present invention without departing from the scope or spirit of the invention. In view of the foregoing, it is intended that the present invention cover modifications and variations of this invention provided they fall within the scope of the following claims and their equivalents.