Patent Publication Number: US-2004042861-A1

Title: Hole saw having peripheral cutting capability

Description:
CROSS-REFERENCES TO RELATED APPLICATIONS  
     [0001] This is a continuation-in-part application of Ser. No. 10/232,642 filed on Aug. 31, 2002. 
    
    
     
       BACKGROUND OF THE INVENTION  
       [0002] 1. Field of the Invention  
       [0003] The present invention relates generally to hole saws and more specifically to a hole saw having peripheral cutting capability that allows cutting in a horizontal plane as well as a vertical plane.  
       [0004] 2. Discussion of the Prior Art  
       [0005] The most common type of hole saw is a cup with teeth formed on the open end, a shank attached to the other end of the cup, and a drill retained in the shank. The drill starts the hole cutting process by providing a pivotal anchor for cutting the hole with the cup. However, an aggravating problem encountered with hole saws is the removal of the slug from the cup. Depending upon the material of the slug, removal of the slug can be a major challenge. If the material is plastic, the plastic slug will heat bond to the inside surface of the cup. There are numerous solutions proposed for removal of the slug. The simplest method of slug removal is to form openings in the top and/or side of the hole saw to allow the slug to be pushed or pried out with a tool.  
       [0006] U.S. Pat. No. 4,652,185 to Malrick discloses hole saws. A spring loaded washer is used to push the slug out of the hole saw. However, if the material is plastic, hand pressure may not be sufficient to push the plastic slug out of the hole saw. U.S. Pat. No. 5,435,672 to Hall et. al discloses a hole saw having plug ejection feature. The hole saw having plug ejection feature includes a screw arbor, which is rotated to eject a slug therefrom. However, this design of hole saw is more complicated than the most common hole saw and requires the screw arbor to be rotated to remove the slug. U.S. Pat. No. 6,206,616 to Smith et al. discloses a tool and method for cutting a circular opening and retaining the cut portion.  
       [0007] It appears that the prior art only discloses hole saws that cut in a vertical plane, not in a horizontal plane. It would be advantageous for a hole saw to be capable of cutting an object in a horizontal plane.  
       [0008] Accordingly, there is a clearly felt need in the art for a hole saw having peripheral cutting capability that allows an opening to be enlarged by moving the hole saw in a horizontal plane.  
       SUMMARY OF THE INVENTION  
       [0009] The present invention provides a hole saw having efficient slug removal that allows a slug to removed therefrom without a tool. The hole saw having efficient slug removal includes a saw cup, a shank portion, and a location drill. A plurality of cutting teeth are formed on an open end of the saw cup and the shank portion is attached to the other end of the saw cup with any suitable fastening process. An opening is formed through the shank to receive the location drill. Preferably, a set screw or the like is used to retain the location drill in the shank portion. The saw cup is modified such that at least two cutting teeth protrude inward. The at least two inward cutting teeth may be two existing cutting teeth bent inward, or at least two inward cutting teeth attached to an inside surface of the saw cup. The at least two inward cutting teeth are preferably located substantially equidistant from each other about the circumference of the open end. The at least two inward cutting teeth create a slug which will fall out of the saw cup.  
       [0010] The location drill is modified such that a cutting diameter has a short length and the remainder of the length is relieved, such that the remainder of the length is smaller in diameter than the cutting diameter. When the hole saw is turned such that the open end is facing downward, the slug drops until it contacts a bottom cutting diameter edge of the location drill. The slug may be removed from the drill by hand. A compression spring may be added to the hole saw to eject the slug when the open end of the saw cup is facing upward. A bottom of the compression spring is attached to a top of the saw cup, on an inside surface of the top.  
       [0011] A hole saw having peripheral cutting capability includes a saw cup, a shank portion, and a location drill. A plurality of cutting teeth are formed on a bottom (open end) of the saw cup and the shank portion is attached to a top of the saw cup with any suitable attachment method. An opening is formed through the shank to receive the location drill. Preferably, a set screw or the like is used to retain the location drill in the shank portion. Peripheral cutting teeth are formed on an outside circumference of the saw cup, at a top thereof. The peripheral cutting teeth may be hobbed, cast, or pressure formed into the saw cup. The peripheral cutting teeth may also be a separate structure that is fastened with any suitable attachment method. The height of the peripheral cutting teeth is preferably half of the height of the saw cup. However, other heights may also be used. An abrasive cutting surface may also be formed on the saw cup.  
       [0012] The hole saw with peripheral cutting capability is used to create a hole in an object. To create a larger hole or opening, the hole saw is plunged into the object, such that the peripheral cutting teeth create a larger opening in the object. The hole may be enlarged by moving the hole saw in a horizontal plane in the desired direction to create a larger opening. A guide plate with a guide opening may be used as a guide for creating an opening with the hole saw having peripheral cutting capability. The corners of the opening may be created with the location drill. The hole saw with peripheral cutting capability may incorporate any of the embodiments of the efficient slug removal structure.  
       [0013] Accordingly, it is an object of the present invention to provide a hole saw having efficient slug removal that reduces the size of the slug.  
       [0014] It is a further object of the present invention to provide a hole saw having efficient slug removal that includes a relieved drill that allows the reduced slug to fall out of the hole saw.  
       [0015] It is yet a further object of the present invention to provide a hole saw having efficient slug removal that includes a compression spring that ejects a slug when the open end of the saw cup is facing upward.  
       [0016] Finally, it is another object of the present invention to provide a hole saw with peripheral cutting capability that enables a hole saw to cut in a horizontal plane.  
       [0017] These and additional objects, advantages, features and benefits of the present invention will become apparent from the following specification. 
     
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
     [0018]FIG. 1 is a bottom view of a hole saw having efficient slug removal in accordance with the present invention.  
     [0019]FIG. 2 is a cross sectional view of a hole saw having efficient slug removal in accordance with the present invention.  
     [0020]FIG. 3 is an enlarged end view of a single cutting tooth bent inward of a hole saw having efficient slug removal in accordance with the present invention.  
     [0021]FIG. 3 a  is an enlarged end view of a single cutting tooth bent slightly inward of a saw cup in accordance with the present invention.  
     [0022]FIG. 4 is an enlarged side view of an inward cutting tooth of a hole saw having efficient slug removal in accordance with the present invention.  
     [0023]FIG. 4 a  is an enlarged side view of an inward cutting tooth that extends substantially the depth of the saw cup of a hole saw having efficient slug removal in accordance with the present invention.  
     [0024]FIG. 5 is an enlarged top view of an inward cutting tooth of a hole saw having efficient slug removal in accordance with the present invention.  
     [0025]FIG. 6 is a side view of a hole saw having efficient slug removal with a slug contacting a cutting diameter edge of a location drill in accordance with the present invention.  
     [0026]FIG. 7 is a cross sectional view of a hole saw having efficient slug removal with a compression spring in accordance with the present invention.  
     [0027]FIG. 8 is a side view of a hole saw having efficient slug removal with at least one removal slot in accordance with the present invention.  
     [0028]FIG. 9 is a top view of a hole saw having efficient slug removal with a compression spring in accordance with the present invention.  
     [0029]FIG. 10 is a side view of a saw cup having cutting teeth replaced with an abrasive cutting surface in accordance with the present invention.  
     [0030]FIG. 11 is a bottom view of a hole saw having peripheral cutting capability with peripheral cutting teeth generated by a hobbing process in accordance with the present invention.  
     [0031]FIG. 12 is a side view of a hole saw having peripheral cutting capability with peripheral cutting teeth generated by a hobbing process in accordance with the present invention.  
     [0032]FIG. 13 is a bottom view of a peripheral cutting ring that is attached to a saw cup in accordance with the present invention.  
     [0033]FIG. 14 is a bottom view of a hole saw having peripheral cutting capability with a peripheral cutting ring attached to the saw cup thereof in accordance with the present invention.  
     [0034]FIG. 15 is a bottom view of a hole saw having peripheral cutting capability with a stop plate attached to a top of a saw cup thereof in accordance with the present invention.  
     [0035]FIG. 16 is a side view of a hole saw having peripheral cutting capability with a stop plate attached to a top of a saw cup thereof in accordance with the present invention.  
     [0036]FIG. 17 is a side view of a hole saw having peripheral cutting capability with an abrasive cutting surface in accordance with the present invention.  
     [0037]FIG. 18 is a top view of a guide plate attached to an object to guide a hole saw having peripheral cutting capability in accordance with the present invention.  
     [0038]FIG. 19 is a cross sectional view of a guide plate attached to an object to guide a hole saw having peripheral cutting capability in accordance with the present invention.  
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS  
     [0039] With reference now to the drawings, and particularly to FIG. 1, there is shown a top view of a hole saw having efficient slug removal  1 . With reference to FIG. 2, the hole saw having efficient slug removal  1  includes a saw cup  10 , a shank portion  12  and a location drill  14 . The shank portion  12  is attached to a closed end of the saw cup  10  with any suitable fastening process, such as welding. The shank portion  12  preferably includes a fastening portion  18  and a chuck shank  20 . A drill opening  22  is formed through the fastening portion  18  and the chuck shank  20  to receive the location drill  14 . A female thread  24  is preferably formed through the fastening portion  18  to the drill opening  22 . A threaded fastener  26  (such as a set screw) is tightened against the location drill  14  to retain thereof relative to the saw cup  10 . However, other designs of shank portions may also be used.  
     [0040] A plurality of cutting teeth  16  are formed on an open end of the saw cup  10 . The saw cup  10  is modified such that at least two inward cutting teeth  28  protrude inward toward a center of the saw cup. The saw cup  10  includes an outside surface  30  and an inside surface  32 . With reference to FIG. 3, the at least two inward cutting teeth  28  may be two existing cutting teeth  16  bent or formed inward. An axis of bending  29  is preferably disposed at substantially a bottom of each inward cutting tooth  28 , but other locations may also be used. However, the more inward cutting teeth  28 , the easier it is for the slug to be removed. For example, the inventor bent  8  cutting teeth  16  inward and found that the slug was easier to remove than when  2 ,  3 , or  4  cutting teeth  16  were bent inward.  
     [0041] With reference to FIG. 3 a , the at least two inward cutting teeth  28  are bent or formed inward to an angle “E.” It is preferable that angle “E” have a value of at least one degree. The at least two inward cutting teeth  28  are preferably located substantially equidistant from each other. For example, angle “D” is preferably 180 degrees. The at least two inward cutting teeth  28  create a slug which will fall out of the saw cup  10 . The slug is the same diameter as the inward tip of the at least two inward cutting teeth  28 . The only resistance to removal of the slug is point contact from the inward tips of the at least two inward cutting teeth  28 . A larger diameter hole saw will require more inward cutting teeth  28  than a smaller diameter hole saw.  
     [0042] With reference to FIGS.  4 - 5 , the saw cup  10  may also be modified by forming at least two inward cutting teeth  36  on an inside surface of the hole saw  10 . The height “B” of the at least two inward cutting teeth  36  is preferably the same as the height of the cutting teeth  16 . The length of each inward cutting tooth  36  is preferably relieved from a top of a cutting edge with an angle “C1” to improve cutting and removal of a slug. A single inward cutting tooth  38  may be used, but the height thereof must be substantially the depth of the saw cup  10 . The inward cutting teeth  36 ,  38  may include a positive or negative rake “C” for cutting different types materials.  
     [0043] The location drill  14  is preferably modified such that the cutting diameter “A” has a short length and the remainder of the length is relieved, such that the remainder of the length has a diameter “A-X,” which is smaller in diameter than the cutting diameter “A.” The value of “X” is preferably at least 0.015 inches. Preferably, the transition from the cutting diameter “A” to the relieved diameter “A-X” is implemented with a straight taper of 10 degrees from the axis of the drill. However, other values and transition shapes besides the 10 degree straight taper may also be used. With reference to FIG. 6, when the hole saw  1  is oriented such that the open end of the saw cup  10  is facing downward, a slug  100  drops until thereof contacts a bottom of the cutting diameter edge  15  of the location drill  14 . The slug  100  may be removed from the location drill  14  by hand. Sometimes the slug will fall off the location drill  14 . For some materials and hole saw sizes, a relieved location drill  14  is not necessary to aid removal of a slug  100 ; the slug  100  will drop off the location drill  14 .  
     [0044] With reference to FIGS. 7 and 9, a compression spring  40  is added to the hole saw  2  to eject a slug, when the open end is facing upward. The compression spring  40  may be retained by creating a spring shank portion  42 . The spring shank portion  42  includes a fastening portion  44 , a chuck shank  46 , and a spring retainer  48 . A drill opening  50  is formed through the fastening portion  44  and the chuck shank  46  to receive the location drill  14 . Preferably, a threaded fastener  26  (such as a set screw) is tightened against the location drill  14  to retain thereof relative to the saw cup  11 . A clearance hole is formed through a top of the saw cup  11  to receive the spring retainer  48 . A spring tap  52  is formed in the spring retainer  48  to threadably receive the compression spring  40 . Preferably, the compression spring  40  is wound in a direction opposite the rotation of the hole saw  2 , such that rotation of the hole saw  2  causes the compression spring  40  to thread into the spring tap  52 . However, other methods of retaining a bottom of the compression spring  40  against a top of the saw cup  10  may also be used, such as welding, adhesive, or retention tabs on the saw cup  10 , which capture a bottom of the compression spring  40 .  
     [0045] At least one removal slot  54  may be formed in a side and/or top of the saw cup  10 ,  11  to provide clearance for a tool (such as a screw driver), which would be used to help remove a slug from the saw cup  10 , if the need should arise. Other openings in the side and top of the saw cup  10 ,  11  may also be formed for helping the removal of an occasional stuck slug.  
     [0046]FIG. 10 shows that the cutting teeth  16  have been replaced with an abrasive cutting surface  56  on the saw cup  10 ′. Other suitable cutting surfaces may also be used besides the cutting teeth  16  and the abrasive cutting surface  56 . At least one inward cutting tooth  36 ,  38  may be formed on an inside surface of the saw cup  10 ′ as shown in FIGS.  4 - 5 .  
     [0047] With reference to FIGS. 11 &amp; 12, a hole saw having peripheral cutting capability  58  includes a saw cup  60 , a shank portion  62 , and a location drill  64 . A plurality of cutting teeth  66  are formed on a bottom (open end) of the saw cup  60  and the shank portion  62  is attached to a top of the saw cup  60  with any suitable fastening process. With reference to FIG. 2, an opening is formed through the shank portion  62  to receive the location drill  64 . Preferably, a set screw or the like is used to retain the location drill  64  in the shank portion  62 .  
     [0048] Peripheral cutting teeth  68  are formed on an outside circumference of the saw cup  60 , at a top thereof. The peripheral cutting teeth  68  may be hobbed into the saw cup  60 ; cast into the saw cup  60  during manufacture, pressure formed into the circumference of the saw cup  60 , or created from the saw cup  60  itself through any other suitable process. The height of the peripheral cutting teeth  68  is preferably half of the height of the saw cup  60 . However, other heights may also be used.  
     [0049] FIGS.  13 - 16  show a second embodiment of a hole saw having peripheral cutting capability  69 . The hole saw having peripheral cutting capability  69  includes a peripheral cutting ring  70 , a saw cup  74 , the shank portion  62 , and the location drill  64 . The peripheral cutting ring  70  includes a plurality of peripheral cutting teeth  72 . The peripheral cutting ring  70  is fastened to an outside circumference of the saw cup  74 , at a top thereof. A plurality of cutting teeth  76  are formed on a bottom (open end) of the saw cup  74  and the shank portion  62  is attached to a top of the saw cup  74  with any suitable fastening process. With reference to FIG. 2, an opening is formed through the shank portion  62  to receive the location drill  64 . Preferably, a set screw or the like is used to retain the location drill  64  in the shank portion  62 . The height of the peripheral cutting ring  70  is preferably half of the height of the saw cup  74 . However, other heights may also be used. FIG. 17 shows a peripheral abrasive cutting surface  78  formed on an outside circumference of the saw cup  74  instead of the peripheral cutting ring  70 .  
     [0050] With reference to FIGS. 18 and 19, the hole saw with peripheral cutting capability  58 ,  69  is used to create a hole in an object  102 . To create a larger hole or opening, the hole saw  58 ,  69  is plunged into the object  102 , such that the peripheral cutting teeth create a larger opening in the object  102 . The hole may be enlarged by moving the hole saw in a horizontal plane in the desired direction to create a larger opening. A guide plate  80  with a guide opening  82  may be used as a guide for creating an opening in the object  102  with the hole saw  58 ,  69 . A stop plate  84  is attached to a top of the saw cup  60 ,  74 . The stop plate  84  enables a user to stop on a top of the guide plate  80 . The corners of an opening  103  formed in the object  102  may be created with the location drill  64 . A hole saw  60 ,  74  with a diameter  104  that is close to the height of the opening  103  may be used or a hole saw  60 ,  74  with a diameter  106  that is smaller than the height of the opening  103 .  
     [0051] The hole saw with peripheral cutting capability  58 ,  69  may incorporate the inward cutting teeth  28 ,  36 ,  38 , a modified location drill  14 , compression spring  40 , or any other efficient slug removal structure.  
     [0052] While particular embodiments of the invention have been shown and described, it will be obvious to those skilled in the art that changes and modifications may be made without departing from the invention in its broader aspects, and therefore, the aim in the appended claims is to cover all such changes and modifications as fall within the true spirit and scope of the invention.