Abstract:
A circle cutter for a sheet product comprises a center knob assembly, an arm, and a cutting assembly. The center knob assembly comprises a base portion adapted to contact a sheet product and fix a position of the cutting assembly relative to the sheet product. The arm is adapted to rotate about the center knob assembly. The arm has a friction reducing element proximate an end of the arm The cutting assembly comprises a cutting portion having a cutting blade. The cutting assembly is releasably fixed to the arm to cut a generally circular pattern into the sheet product as the arm rotates about the center knob assembly.

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
       [0001]    This application claims priority to U.S. Provisional Patent Application Ser. No. 61/353,525 filed Jun. 10, 2010. 
     
    
     TECHNICAL FIELD 
       [0002]    The present invention relates to a craft cutting device, and more particularly, to a craft cutting device adapted to cut sheet products into generally circular shapes using a blade. 
       BACKGROUND OF THE INVENTION 
       [0003]    When working on craft projects it is often necessary to cut sheet products, such as paper, poster board, fabric, and the like, into a generally circular shape. Currently, a person working on a craft project has few options to accurately cut the sheet product into a circular shape. The user may use a compass to inscribe a circle into the sheet, and then use a cutting device, such as a knife or scissors to cut through the sheet by following the inscribed circle. Additionally, it is known to have a template with a known diameter, and the user places the template over the sheet and then cuts around the exterior of the template. These existing methods and devices have certain drawbacks. For example, the use of a compass often punches a hole in the sheet, while a template is only useful to make a cutout of a predetermined size. Thus, a need exists for a circular cutter that overcomes some of these limitations. 
         [0004]    The present invention is provided to solve the problems discussed above and other problems, and to provide advantages and aspects not previously provided. A full discussion of the features and advantages of the present invention is deferred to the following detailed description, which proceeds with reference to the accompanying drawings. 
       SUMMARY OF THE INVENTION 
       [0005]    According to one embodiment, a circular cutter for a sheet product comprises a center knob assembly, an arm, and a cutting assembly. The center knob assembly comprises a base portion and a knob portion. The base portion has a center section projecting upward. The knob portion is releasably attached to the center section of the base. The arm rotatably couples to the center knob assembly and has an elongated opening and a generally circular opening. The generally circular opening is disposed proximate a first end of the arm. The center section of the base core extends through the generally circular opening. The knob portion of the center knob assembly is disposed generally above the arm. The arm further comprises a friction reducing element disposed proximate a second end of the arm. The cutting assembly couples to the elongated opening of the arm. The cutting assembly comprises a cutting portion and an activation portion. The cutting portion has a cutting blade. The cutting assembly is moveable along the elongated opening of the arm. 
         [0006]    According to another embodiment, a circle cutter for a sheet product comprises a center knob assembly, an arm, and a cutting blade. The center knob assembly comprises a base portion adapted to contact a sheet product and fix a position of the cutting assembly relative to the sheet product. The arm connects to the center knob assembly. The arm is rotatable about the center knob assembly and has a friction reducing element proximate an end of the arm. The cutting blade couples to the arm and is moveable along at least a portion of a length of the arm. 
         [0007]    Other features and advantages of the invention will be apparent from the following specification taken in conjunction with the following drawings. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0008]    To understand the present invention, it will now be described by way of example, with reference to the accompanying drawings in which: 
           [0009]      FIG. 1  is a top view of a circle cutter with a blade in a stored position according to one embodiment; 
           [0010]      FIG. 2  is a bottom view of the circle cutter of  FIG. 1 ; 
           [0011]      FIG. 3  is a side view of the circle cutter of  FIG. 1 ; 
           [0012]      FIG. 4  is a detailed side view of the circle cutter of  FIG. 1 ; 
           [0013]      FIG. 5  top view of the circle cutter of  FIG. 1  with the blade in a cutting position; 
           [0014]      FIG. 6  is a bottom view of the circle cutter of  FIG. 5 ; 
           [0015]      FIG. 7  is detailed view of a blade of the circle cutter of  FIG. 5 ; and 
           [0016]      FIG. 8  is a detailed view of a center knob assembly of the circle cutter of  FIG. 5 . 
       
    
    
       [0017]    The components in the drawings are not necessarily to scale, emphasis instead being placed upon clearly illustrating the principles of the present invention. 
       DETAILED DESCRIPTION 
       [0018]    While this invention is susceptible of embodiments in many different forms, there is shown in the drawings and will herein be described in detail preferred embodiments of the invention with the understanding that the present disclosure is to be considered as an exemplification of the principles of the invention and is not intended to limit the broad aspect of the invention to the embodiments illustrated. 
         [0019]    According to one embodiment of the present invention, as shown in  FIGS. 1-8 , a circle cutter  10  is provided. The circle cutter  10  comprises a center knob assembly  12 , an arm  14 , and a cutting assembly  16 . 
         [0020]    As best shown in  FIGS. 1 and 2 , the center knob assembly  12  has a base  18  and a knob  20 . The base  18  has a surface gripping portion  22 . The base  18  has a cylindrical center section that extends upward from a bottom of the base  18  and through the arm  14 . The gripping portion  22  may be secured to the base  18  via an adhesive, a press fit, fasteners, or other known attaching methods, but an adhesive has been found to be particularly well suited to hold the gripping portion  22  to the base  18 . The gripping portion  22  is adapted to rest on the sheet being cut by the circle cutter  10 . The gripping portion  22  may be made from a polymeric material or a polymeric foam material that is slip resistant when used with paper, paperboard, cardboard, or the like, so that the circle cutter generally resides in one location on the sheet during use. The gripping portion  22  has a generally flat bottom such that the contact of the gripping portion  22  with the sheet provides sufficient surface area to resist movement of the circle cutter  10  relative to the sheet. 
         [0021]    The knob  20  attaches to the cylindrical center section of the base  18 . It is contemplated that the cylindrical center section of the base  18  to connect the base  18  and the knob  20 . For instance, the cylindrical center section and the knob  20  may be threaded, or have a snap-fit configuration to removably connect the base  18  to the knob  20 . Removing the knob  20  from the base  18  allows access to a storage area that may contain accessories for the circle cutter  10 , such as additional blades. It is also contemplated that the knob  20  may conform to various geometric configurations suitable for providing a gripping surface for user. 
         [0022]    The arm  14  has an elongated opening or slot  24  and a generally circular opening. The elongated opening  24  is adapted to receive the cutting assembly  16  and allows a position of the cutting assembly  16  to be adjusted based on the size of a circle that is desired to be cut into the sheet. In order to more accurately determine the position of the cutting assembly  16 , measuring indicia  26  are provided on the arm  14  along the elongated opening  24 . Thus, a user may position the cutting assembly  16  next to a measuring indicia  26  indicative of a diameter of a circle the user wishes to cut in the sheet. In one embodiment, the circle cutter  10  may be used to cut a circle with a diameter from about ten (10) cm to about thirty and a half (30.5) cm. However, the concepts of the present invention also apply to both larger and smaller circle cutters without departing therefrom. 
         [0023]    The circular opening of the arm  14  is adapted to receive the cylindrical center section of the base  18  therethrough. Thus, the arm  14  is secured between the base  18  and the knob  20  of the center knob assembly  12 . The arm  14  is adapted to rotate relative to the center knob assembly  12  and thereby rotate the cutting assembly  16  relative to the center knob assembly  12 . A bottom surface of the arm  14  is adapted to contact a generally horizontal surface of the base  18 , thus the arm  14  is at least partially supported by the base  18  of the center knob assembly  12 . 
         [0024]    The cutting assembly  16  comprises a cutting portion  28  and an activation portion  30 . The cutting portion  28  has a cutting blade  32 . The cutting blade  32  is adapted to pass through a sheet product in order to cut the sheet product. As the cutting blade  32  moves through the sheet a circle is cut into the sheet. The blade  32  may be formed from a variety of materials including metals and polymeric materials, but stainless steel may be favored due to its durability and compatibility in use with a variety of materials. 
         [0025]    The cutting blade  32  is removably connected to the cutting portion  28 . A press fit may be used to secure the cutting blade  32  to the cutting portion  28 , thus allowing a user to easily remove the cutting blade  32 . When the cutting blade  32  is removed, it may be replaced with a generally identical blade, such as if the cutting blade  32  has become dull, or a cutting blade with a different cutting surface, such as to form a different type of cut, or to be utilized in a different sheet material. 
         [0026]    The activation portion  30  comprises a slidable base  34 . The slidable base  34  is adapted to contact a top surface of the elongated opening  24  of the arm  14 . The activation portion  30  may contain a first biasing member. The first biasing member biases the slidable base  34  towards the arm  14  so that the slidable base  34  may engage at least one of a plurality of detents  36  provided along the elongate opening  24 . The detents  36  allow the cutting assembly  16  to be secured at a number of predefined positions along the arm  14 . 
         [0027]    The activation portion  30  is adapted to move vertically downward in response to a force applied to the activation portion  30  to displace the cutting blade  32  vertically downward into the sheet material. Thus, the blade  32  only contacts the sheet material when a force is applied to the activation portion  30 . It is contemplated that the activation portion  30  may also comprise a second biasing member adapted to bias the cutting blade  32  to a first position where the cutting blade  32  does not contact the sheet material. The first and second biasing members of the activation portion may be a spring, a compressible polymeric material, a foam, a gas strut, a hydraulic strut, or the like. 
         [0028]    Thus, an upward vertical force on the activation portion  30  allows the cutting assembly  16  to be moved along the arm  14 , while a downward force on the activation portion  30  allows the cutting blade  32  to contact the sheet material. 
         [0029]    The arm  14  may also comprise a friction reducing element  38 . The friction reducing element  38  can be a ball bearing, roller, or any other suitable mechanism for reducing contact friction. The friction reducing element  38  is adapted to assist the rotation of the arm on the sheet material, by allowing the arm  14  to smoothly pass over the sheet material by reducing the friction between the arm  14  and the sheet material. It is contemplated that the friction reducing element will be disposed on the arm  14  at an end opposite the center knob assembly  12 . Thus, once cutting blade  32  is placed into the sheet material, the arm  14  can be rotated about the center knob  12  in order to perform a circular cut of the sheet. 
         [0030]    The arm  14  may also comprise bristles  40 . The bristles may be provided in a first row  40   a  on a first side of the arm  14  and a second row  40   b  on a second side of the arm  14 . The bristles  40  are adapted to collect material from the sheet that is cut by the cutting blade  32  during the use of the circle cutter  10 . 
         [0031]    It is additionally contemplated that the base  18  may comprise a blade receptacle  42 . The blade receptacle  42  is adapted to receive the cutting blade  32  when the cutting assembly  16  is placed in a storage position in close proximity to the base  18  along the arm  14 . The placement of the cutting blade  32  into blade receptacle  42  also inhibits rotation of the arm  14  about the base  12 . 
         [0032]    While specific embodiments have been illustrated and described, numerous modifications come to mind without significantly departing from the spirit of the invention, and the scope of protection is only limited by the scope of the accompanying Claims.