Patent Publication Number: US-7896589-B2

Title: Cutter for engagement with an arbor

Description:
BACKGROUND OF THE INVENTION 
     1. Field of the Invention 
     The invention relates to a cutter, e.g., an annular cutter, for engagement with an arbor of a drill machine. 
     2. Description of the Related Art 
     Cutters, e.g., annular cutters, are known in the art for engagement with a drill machine for cutting holes in a workpiece. The drill machine includes a housing and a motor coupled to the housing. The arbor is coupled to the motor for rotation with the motor. The arbor defines a bore and the cutter is engaged to the arbor in the bore. A driving device is coupled to the arbor and extends into the bore for engaging the cutter, i.e., to lock the cutter in the bore. The driving device transmits rotation from the arbor to the cutter. 
     The driving device can be further defined as a set screw that threadedly extends through the arbor and into the bore. The set screw is rotated to threadedly advance and retreat the set screw into and out of the bore to engage and disengage the drill machine, respectively. 
     Alternatively, the driving device can be further defined as an extending member, e.g., a ball, extending into the bore of the arbor. In such a configuration, the cutter must define a retaining recess such that the extending member engages the cutter in the retaining recess. It is known in the art to provide a locking mechanism for moving the extending member radially within the bore. The locking mechanism moves the extending member is radially outwardly to allow the cutter to be inserted into the bore and removed from the bore. The locking mechanism moves the extending member radially inwardly to engage the extending member with the retaining recess to lock the cutter in the bore. 
     Both when the driving device is defined as a set screw or as an extending member, the engagement and disengagement of the cutter with the arbor is needlessly complicated and time consuming. With respect to the set screw, the threaded advancement and retreat of the set screw is time consuming. In addition, a hand tool such as an allen wrench, i.e., hex wrench, is required to threadedly advance and retreat the set screw into and out of the bore. With respect to the locking mechanism, the locking mechanism often requires two hands to operate, i.e., one hand to hold the cutter and another hand to operate the locking mechanism. In addition, the locking mechanism is costly and complicated to design and manufacture. 
     As such there remains the need for an cutter that is quickly and easily engaged and disengaged with the arbor. There also remains the need for a cutter that can be engaged and disengaged with the arbor without the need for a tool or a locking mechanism to lock the cutter to the arbor. 
     SUMMARY OF THE INVENTION AND ADVANTAGES 
     The present invention is a cutter for driven engagement with a driving device of an arbor. The cutter comprises a shank portion having a central axis and extending along the central axis between a first end and a second end. The shank portion defines an entry channel extending from the second end for guiding the driving device of the arbor during insertion of the shank portion into the arbor and a retaining channel extending from the entry channel for selectively retaining the driving device of the arbor. A cutting portion extends from the first end of the shank portion. Each of the entry and retaining channels have a trough portion extending toward the central axis with the trough portions of each of the entry and retaining channels having a common configuration for slideably receiving the driving device. 
     The cutter is easily and quickly engaged and disengaged with the arbor by a push and twist motion. The second end of the cutter is inserted in the arbor and the entry channel is aligned with the driving device. The cutter is moved into the arbor with the driving device sliding along the entry channel. When the driving device reaches the retaining channel, the cutter is twisted, i.e., rotated, to slide the driving device into the retaining channel. 
     Additionally, the cutter is engaged and disengaged with the arbor without the need for a hand tool or a locking mechanism. Notably, the cutter can be used with an arbor having a locking mechanism and is interchangeable among several arbors each having different types of locking mechanisms. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       Other advantages of the present invention will be readily appreciated, as the same becomes better understood by reference to the following detailed description when considered in connection with the accompanying drawings wherein: 
         FIG. 1  is a cross-sectional view of a drill machine including a cutter disengaged from the drill machine and an extending member for engaging the cutter; 
         FIG. 2  is a cross-sectional view of the drill machine engaged with the extending member; 
         FIG. 3  is a cross-sectional view of another embodiment of the drill machine including a pair of set screws for engaging the cutter; 
         FIG. 4  is a side view of a portion of the cutter; 
         FIG. 5  is a top view of a shank portion of the cutter; 
         FIG. 6  is a cross-sectional view of the cutter through line  6  of  FIG. 4 ; 
         FIG. 7  is a cross-sectional view of the cutter through line  7  of  FIG. 4 ; 
         FIG. 8  is a cross-sectional view of the cutter through line  8  of  FIG. 2 ; 
         FIG. 9  is a cross-sectional view of the cutter through line  9  of  FIG. 3 ; 
         FIG. 10A  is a side view of a portion of another embodiment of the cutter; 
         FIG. 10B  is a top view of a portion of the embodiment of the cutter shown in  FIG. 10A ; 
         FIG. 11A  is a side view of a portion of yet another embodiment of the cutter; and 
         FIG. 11B  is a top view of a portion of the embodiment of the cutter shown in  FIG. 11A . 
     
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
     Referring to the Figures, wherein like numerals indicate like parts throughout the several views, a drill machine is generally shown at  20 . As shown in  FIGS. 1-3 , the drill machine  20  includes a housing  22  and a motor  24  coupled to the housing  22 . As appreciated by one skilled in the art, the housing  22  and the motor  24  are generically depicted in the Figures and the housing  22  and motor  24  can be of any type. An arbor  26  is coupled to the motor  24  for rotation with the motor  24 . The arbor  26  defines a bore  28  and a driving device  30  is coupled to the arbor  26  and extends into the bore  28 . As will be discussed below and as best shown in  FIGS. 2 and 3 , a cutter  32  is partially inserted into the bore  28  and is coupled to the arbor  26  with the driving device  30 . The cutter  32  partially extends from the bore  28  for cutting a workpiece (not shown), which is typically formed from a rigid material such as metal. The cutter  32  rotates relative to the housing  22  to cut a hole in the workpiece. For example, the cutter  32  is sized to cut holes sized between 7/16-2⅜ inches in diameter and 1-3 inches deep. It should be appreciated that the size of the holes can be any size without departing from the nature of the present invention. 
     The cutter  32  is more specifically referred to in industry as an annular cutter  32 . The cutter  32  includes a shank portion  34  and a cutting portion  36 . The cutter  32  extends along a central axis C and each of the shank portion  34  and the cutting portion  36  extend along the central axis C. The shank portion  34  extends along the central axis C between a first end  38  and a second end  40 . The cutting portion  36  extends from the first end  38  of the shank portion  34 . As best shown in  FIGS. 2 and 3 , the second end  40  of the shank portion  34  is inserted into the bore  28  of the arbor  26  and is coupled to the arbor  26  with the driving device  30  and the cutting portion  36  extends from the arbor  26 . 
     The cutter  32  is typically formed from metal such as, for example, high speed steel. More specifically, for example, the high speed steel may be M2 steel or M42 steel. However, it should be appreciated that the cutter  32  can be formed from any rigid material known to one skilled in the art without departing from the nature of the present invention. The cutter  32  can include inserts, e.g., carbide inserts (not shown), along a tip of the cutting portion  36  to extend the life of the cutter  32 . 
     The driving device  30  engages the cutter  32  to translate rotational motion from the arbor  26  to the cutter  32 . The driving device  30  is further defined as one of an extending member  42  engaged with the arbor  26  in the bore  28 , as best shown in  FIGS. 2 and 8 , and a pair of set screws  44 , as best shown in  FIGS. 3 and 9 . As will be discussed below, in the configuration shown in  FIGS. 2 and 8 , the extending member  42  engages the cutter  32  and, in the configuration shown in  FIGS. 3 and 9 , the pair of set screws  44  engage the cutter  32 . The extending member  42  shown in  FIGS. 1 and 2  is further defined as a ball. However, it should be appreciated that the extending member  42  can be of any type that is engaged with the arbor  26  in the bore  28 , such as, for example, a dowel pin. The extending member  42  is selectively moveable radially in the bore  28 , i.e., toward and away from the shank portion  34 . For example, in the configuration as best shown in  FIGS. 1 ,  2 , and  8 , the arbor  26  includes a collar  46  that engages the extending member  42 . The collar  46  is rotated to move the extending members  42  radially in the bore  28 . Alternatively, the extending member  42  is fixed in position in the bore  28 . 
     The shank portion  34  defines a retaining recess  48  and a pair of flats  50 . The driving device  30  engages one of the retaining recess  48  and the pair of flats  50 . In other words, the driving device  30  engages either the retaining recess  48  or at least one of the pair of flats  50 . Specifically, when the driving device  30  is the extending member  42 , as shown in  FIGS. 2 and 8 , the extending member  42  engages the retaining recess  48 . When the driving device  30  is the pair of set screws  44 , as shown in  FIGS. 3 and 9 , the pair of set screws  44  engages the pair of flats  50 . In other words, the cutter  32  is interchangeable between arbors  26  that have driving members further defined as extending members  42 , e.g., balls, and arbors  26  that have driving members further defined as set screws  44 . 
     The retaining recess  48  can be further defined as a plurality of retaining recesses  48  spaced from each other circumferentially about the shank portion  34 . In such a configuration, the driving device  30  is further defined as a plurality of extending members  42  spaced circumferentially in the bore  28  of the arbor  26  with each extending member  42  slideable along one of the retaining recesses  48 , respectively. In the embodiment shown in Figures, the cutter  32  has three retaining recesses  48  and the arbor  26  shown in  FIGS. 2 and 8  has three extending members  42  spaced about the bore  28  to engage each retaining recess  48 . It should be appreciated that the cutter  32  can have any number of retaining recesses  48  and the arbor  26  can have a corresponding number of extending members  42  without departing from the nature of the present invention. 
     In an embodiment where the shank portion  34  has a plurality of retaining recesses  48 , the retaining recesses  48  are typically evenly spaced circumferentially about the shank portion  34 . For example, as best shown in  FIG. 5 , the three retaining recesses  48  are circumferentially spaced 120 degrees apart from each other. However, it should be appreciated that the plurality of retaining recesses  48  can be spaced at any interval circumferentially about the shank portion  34 . 
     As best shown in  FIG. 4 , the retaining recess  48  is further defined as an entry channel  52  and a retaining channel  54  extending from the entry channel  52 , i.e., the shank portion  34  defines the entry channel  52  and the retaining channel  54 . In the configuration shown in the Figures including the plurality of retaining recesses  48 , each of the retaining recesses  48  include one of the entry channels  52  and one of the retaining channels  54  extending from the entry channel  52 . 
     The entry channel  52  extends from the second end  40  of the shank portion  34  for guiding the driving device  30  of the arbor  26  during insertion of the shank portion  34  into the arbor  26 . The retaining channel  54  selectively retains the driving device  30  of the arbor  26 . Specifically, in the configuration shown in  FIG. 2 , the engagement between the retaining channel  54  and the extending member  42  vertically retains the cutter  32  in the arbor  26  and, as best shown in  FIG. 8 , rotation of the arbor  26  in the right direction, i.e., clockwise, drives the extending members  42  and the cutter  32  in the right direction. 
     In the configuration where the driving device  30  is further defined as at least one extending member  42 , the extending members  42  are slideable along the entry and retaining channels  52 ,  54 . For example, in the configuration where the driving device  30  is further defined as the ball engaged with the arbor  26 , the ball is slideable along the entry and retaining channels  52 ,  54 . The second end  40  of the shank portion  34  is inserted into the bore  28  of the arbor  26 . The cutter  32  is rotated to align the extending members  42  with the entry channels  52  at the second end  40  of the shank portion  34 . When the entry channels  52  are aligned with the extending members  42 , the cutter  32  is moved into the bore  28  with the extending members  42  sliding along the entry channels  52 . The extending members  42  are aligned with the retaining channels  54  when the extending members  42  are moved along the length of the entry channel  52 . In the configuration shown in the Figures, when the extending members  42  are aligned with the retaining channels  54 , the cutter  32  is rotated in the right direction, i.e., clockwise, to the position shown in  FIG. 8 . In such a configuration, the motor  24  rotates the arbor  26  in the right direction such that the extending members  42  drive the cutter  32  such that the cutter  32  is rotated in the right direction. It should be appreciated that the configuration of the shank portion  34  and the arbor  26  to accommodate the rotation of the motor  24  in the right direction is shown for exemplary purposes. Alternatively, the shank portion  34  and the arbor  26  may be configured to accommodate the rotation of the motor  24  in the left direction. In such a configuration, the shank portion  34  and the arbor  26  are mirror images of the configuration shown in  FIG. 8  in which case the motor  24  rotates the arbor  26  in the left direction such that the extending members  42  drive the cutter  32  such that the cutter  32  is rotated in the left direction. 
     The method described above allows for quick engagement and disengagement of the cutter  32  and the arbor  26  because the only required movement is the axial translation of the cutter  32  in a direction along the central axis C and the rotational movement of the cutter  32  about the central axis C. The cutter  32  can typically be engaged and disengaged with the arbor  26  with the use of only one hand. Notably, the cutter  32  does not require an arbor  26  that has moving extending members  42  to move into and out of engagement with the retaining recess  48 . In other words, the cutter  32  can be used in the arbor  26  that has extending members  42  fixed in position in the bore  28  as well as the arbor  26  that has extending members  42  that selectively move into and out of the bore  28 . 
     The shank portion  34  presents a cylindrical surface  56  extending circumferentially about the central axis C and the entry and retaining channels  52 ,  54  are defined in the cylindrical surface  56 . Each of the entry and retaining channels  52 ,  54  has a first channel edge portion  58  and a second channel edge portion  60  spaced from each other with a trough portion  62  extending from the first channel edge portion  58  to the second channel edge portion  60 . The first and second edge portions  58 ,  60  are further defined as boundaries between the cylindrical surface  56  and the trough portion  62 , i.e., the first and second edge portions  58 ,  60  do not need to present angles between the cylindrical surface  56  and the trough portion  62  and can alternatively be rounded. Each trough portion  62  extends toward the central axis C between the first and second channel edge portions  58 ,  60 . The trough portions  62  of each of the entry and retaining channels  52 ,  54  have a common configuration for slideably receiving the driving device  30 . 
     The common configuration includes the depth of the trough portion  62 , i.e., the trough portion  62  of each of the entry and retaining channels  52 ,  54  extend at a common depth D measured radially from the central axis C. The common depth D allows the extending member  42  to freely slide along the entry and retaining channels  52 ,  54  without interference with a bottom of the trough portion  62 , i.e., without bottoming out. It should be appreciated that the entry and retaining channels can have differing depths without departing from the nature of the present invention. For example, the entry and/or retaining channels  52 ,  54  can present a ramp for selectively retaining the extending member  42  in the retaining channel  54 . 
     Another common configuration includes the width of the trough portion  62 , i.e., each of the entry and retaining channels  52 ,  54  has a width W measured between and transverse to the first and second channel edges with the width W of the entry channel  52  equal to the width W of the retaining channel  54 . The common width W allows the extending member  42  to freely slide along the entry and retaining channels  52 ,  54  without interference with the first and second channel edge portions  58 ,  60 . It should be appreciated that the entry and retaining channels  52 ,  54  can have different widths without departing from the nature of the present invention. Also, it should be appreciated that the widths of the entry and retaining channels  52 ,  54  can vary along the lengths of the entry and retaining channels  52 ,  54 , respectively, without departing from the nature of the present invention. 
     Yet another common configuration includes the cross-sectional shape of the trough portion  62 , i.e., each of the entry and retaining channels  52 ,  54  has a cross-sectional shape and the cross-sectional shape of the entry channel  52  is the same as the cross-sectional shape of the retaining channel  54 . However, it should be appreciated that the cross-sectional shape of the entry channel  52  can be different than the cross-sectional shape of the retaining channel  54  without departing from the nature of the present invention. Typically, the driving device  30  is complimentary in configuration to the cross-sectional shape of the entry and retaining channels  52 ,  54 , e.g., a cross-section of a portion of the extending member  42  that slides along the entry and retaining channels  52 ,  54  is the same as the cross-section of the entry and retaining channels  52 ,  54 . In the configuration shown in  FIGS. 1 ,  2 , and  8 , the cross-sectional shape is further defined as an arc and the driving devices  30 , i.e., the balls, have a spherical shape. As best shown in  FIG. 2 , the cross-section of the portion of the extending member  42  that slides along the entry and retaining channels  52 ,  54  is arced and thereby is complimentary in configuration to the cross-sectional shape of the entry and retaining channels  52 ,  54 . 
     Alternatively, as shown in  FIG. 10A-B , the cross-sectional shape of the trough portion  62  is V-shaped. In such a configuration, the cross-section of the portion of the extending member  42  that slides along the entry and retaining channels  52 ,  54  can be V-shaped. As shown in  FIGS. 11A-B , the cross-sectional shape of the trough portion  62  is square-shaped. In such a configuration, the cross-section of the portion of the extending member  42  that slides along the entry and retaining channels  52 ,  54  can be squared. However, it should be appreciated that the extending members  42  can be further defined as balls having the spherical shape for use with both the V-shaped entry and retaining channels  52 ,  54  and the square-shaped entry and retaining channels  52 ,  54 . 
     It should be appreciated that the cross-sectional shape of the trough portion  62  may be any shape without departing from the nature of the present invention. It should also be appreciated that while the driving device  30  is typically complimentary in configuration to the cross-sectional shape of the entry and retaining channels  52 ,  54 , the cross-section of the portion of the driving device  30  that slides along the entry and retaining channels  52 ,  54  can be different than the cross-sectional shape of the trough portion  62  without departing from the nature of the present invention. 
     The entry channel  52  extends along the shank portion  34  in a first direction D 1  and the retaining channel  54  extends along the shank portion  34  in a second direction D 2  different than the first direction D 1 . Typically, the first direction D 1  extends approximately perpendicular to the second direction D 2 . Specifically, as best shown in  FIG. 4 , the entry channel  52  extends axially along the shank portion  34 . In other words, the entry channel  52  extends in parallel with the central axis C of the cutter  32 . The retaining channel  54  extends circumferentially along the shank portion  34 . However, it should be appreciated that the entry channel  52  can extend at an angle relative to the central axis C and the first direction D 1  can extend at a non-perpendicular angle relative to the second direction D 2  without departing from the nature of the present invention. 
     The entry portion extends along a longitudinal axis L and the retaining channel  54  extends at an angle A 2  circumferentially about the central axis C from the longitudinal axis L to a retaining channel end  64 . For example, the angle A 2  is between 50 and 60 degrees. More specifically, the retaining channel  54  extends at approximately 55 degrees circumferentially about the central axis C from the longitudinal axis L to retaining channel end  64 . For example, as best shown in  FIG. 8 , the extending member  42  is sized such that the cutter rotates at an angle A 3  relative to the extending member. For example, the angle A 3  is between 30 and 40 degrees. For example, in a configuration where the angle A 3  is 35 degrees, when the second end  40  of the shank portion  34  is inserted into the bore  28  and the extending member  42  is aligned with the retaining channel  54 , the cutter  32  is rotated approximately 35 degrees in the right direction to fully engage the cutter  32  with the arbor  26 . It should be appreciated that angle A 2  and angle A 3  can be of any magnitude without departing from the nature of the present invention. 
     As best shown in  FIGS. 5-7 , one of the pair of flats  50  extends in a first plane P 1  and the other of the pair of flats  50  extends in a second plane P 2 . As best shown in  FIG. 6 , the first and second planes P 1 , P 2  extend at an angle A 1  relative to each other. Preferably the angle A 1  is 90 degrees, i.e., the second plane P 2  extends perpendicular to the first plane P 1 . As best shown in  FIG. 9 , in the configuration where the extending member  42  is further defined as the pair of set screws  44 , the arbor  26  defines set screw holes and the set screws  44  are threadedly engaged with the set screw holes. In the configuration where the angle A 1  is 90 degrees, the set screw holes are arranged approximately 90 degrees apart circumferentially and extend approximately perpendicularly relative to each other. 
     The position of the pair of flats  50  perpendicular to each other allows for stable engagement between the arbor  26  and the cutter  32 . Specifically, the pair of set screws  44  engaging the pair of perpendicular flats  50  forces the cutter  32  against the bore  28  of the arbor  26  and centers the cutter  32  in the arbor  26 . The position of the pair of flats  50  perpendicular to each other also allows for effective transmission of rotational motion from the arbor  26  to the cutter  32 . In other words, each of the set screws  44  engage the flats  50 , respectively, to transmit rotation of the arbor  26  to the cutter  32 . 
     In such a configuration, the second end  40  of the shank portion  34  is inserted into the bore  28  of the arbor  26 . The cutter  32  is rotated to align the pair of flats  50  with the pair of set screws  44 . When the pair of flats  50  are aligned with the pair of set screws  44 , the set screws  44  are threadedly advanced toward the cutter  32  to engage the pair of flats  50 , as shown in  FIG. 9 . The motor  24  rotates the arbor  26  and the set screws  44  drive the cutter  32  such that the cutter  32  is rotated with the arbor  26 . It should be appreciated that the cutter  32  can also be used with an arbor  26  that has only one set screw  44  and in such a configuration the one set screw  44  is threadedly advanced to engage one of the pair of flats  50 . 
     As best shown in  FIG. 6 , the pair of flats  50  are spaced from each other with the retaining recess  48  disposed between the pair of flats  50 . As best shown in  FIG. 5 , the pair of flats  50  are recessed toward the central axis C from the cylindrical surface  56 . As best shown in  FIG. 5 , the shank portion  34  has a reference plane RP extending through the central axis C and the longitudinal axis L. The first plane P 1  of one of the pair of flats  50  extends at an angle A 4  from the reference plane RP and the second plane P 2  of the other of the pair of flats  50  extends at an angle A 5  from the reference plane RP. In the embodiment shown in  FIG. 5 , the first plane P 1  extends at approximately 45 degrees from the reference plane RP, i.e., the angle A 4  is 45 degrees, and the second plane P 2  extends at approximately 135 degrees from the reference plane RP, i.e., the angle A 5  is 135 degrees. 
     The drill machine  20  and the arbor  26  can include a lubrication system  66  as shown in  FIGS. 1-3 . In such a configuration, the cutter  32  defines a hole extending along the central axis C and the cutter  32  slideably receives a pilot  68  in the hole. When the cutter  32  is contacted to the workpiece, the pilot  68  is forced upwardly to allow lubricant to flow from the arbor  26  toward the workpiece. It should be appreciated that the drill machine  20  and the arbor  26  can include any type of lubrication system  66  without departing from the nature of the present invention. 
     The invention has been described in an illustrative manner, and it is to be understood that the terminology which has been used is intended to be in the nature of words of description rather than of limitation. Obviously, many modifications and variations of the present invention are possible in light of the above teachings, and the invention may be practiced otherwise than as specifically described.