Abstract:
A quick connect/disconnect mechanism for a rotary bit having a central mounting hole at a proximal end includes a shaft extending axially and having a proximal end adapted to be releasably secured in a rotary tool and a distal end having a spud extending distally and axially therefrom. A plurality of retainer arms are arrayed about the axis and extending distally, each retainer arm including a catch extending radially outwardly from a distal end thereof. A release sleeve extends about the shaft adjacent to said distal end, the release sleeve having engagement keys to impinge on the proximal ends of the retainer arms, the sleeve being rotatable from a first position in which the engagement keys hold the retainer arms to secure the rotary bit to a second position in which the retainer arms rotate to release the rotary bit.

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
       [0001]    This application is a continuation-in-part of Ser. No. 14/070,236, filed Nov. 1, 2013, which is a continuation of Ser. No. 61/796,251, filed Nov. 4, 2012, from which filing date priority is claimed. 
     
    
     STATEMENT REGARDING FEDERALLY SPONSORED RESEARCH OR DEVELOPMENT 
       [0002]    Not Applicable 
       REFERENCE TO SEQUENCE LISTING, A TABLE, OR A COMPUTER PROGRAM LISTING COMPACT DISK APPENDIX 
       [0003]    Not Applicable 
       FIELD OF THE INVENTION 
       [0004]    The present disclosure relates to holesaws and, more particularly, a mandrel assembly for receiving holesaws. 
       BACKGROUND OF THE INVENTION 
       [0005]    There are a variety of hole saw mandrel designs disclosing various quick release mechanism that exist in the art. These designs allow the user to “swap out” hole saw bits in a fraction of the time it would take with a traditional mandrel. However, the problem with these designs is they all require the user to attach a external quick disconnect member to every one of their hole saw bits. There are many disadvantages to this approach, first once the quick release members have been attached to the user&#39;s bits they will no longer fit in the case they came with. Second, the extra cost associated with these male members and the time required to attach them is a disadvantage. Finally, one of the primary reasons the user removes the saw bit is to remove the wooden plug, unfortunately the attached quick release members substantially obscures the hole typically used to push them out. Therefore, it would be advantageous if a quick release mandrel existed in the art that did not require the user to mount an external quick release member to their existing saw bits. 
       SUMMARY OF THE INVENTION 
       [0006]    Accordingly, the present invention addresses this situation by providing a hole saw mandrel with integrated quick connect/disconnect saw bit retention means that does not require the use of a external quick release members. 
         [0007]    Other advantages of the present invention will become apparent to those skilled in this art from the following description and drawings wherein there is described and shown a preferred embodiment of this invention in one of the best modes contemplated for carrying out the invention. As will be realized, the invention is capable of other modification in various, obvious aspects all without departing from the invention. Accordingly, the drawings and descriptions will be regarded as illustrative in nature and not as restrictive. 
         [0008]    Other novel features characteristic of the invention, as to organization and method of operation, together with further objects and advantages thereof will be better understood from the following description considered in connection with the accompanying drawings, in which preferred embodiments of the invention are illustrated by way of example. It is to be expressly understood, however, that the drawings are for illustration and description only and are not intended as a definition of the limits of the invention. The various features of novelty that characterize the invention are pointed out with particularity in the claims annexed to and forming part of this disclosure. The invention does not reside in any one of these features taken alone, but rather in the particular combination of all of its structures for the functions specified. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0009]      FIG. 1  is a perspective view of embodiment  100  of the present invention. 
           [0010]      FIG. 2  is an exploded view of embodiment  100  of the present invention. 
           [0011]      FIG. 3  is a sectional view of embodiment  100  of the present invention. 
           [0012]      FIG. 4  is a sectional view of embodiment  100  of the present invention. 
           [0013]      FIG. 5  is a sectional view of embodiment  100  of the present invention. 
           [0014]      FIG. 6  is an exploded view of embodiment  200  of the present invention. 
           [0015]      FIG. 7  is a sectional view of embodiment  200  of the present invention. 
           [0016]      FIG. 8  is a sectional view of embodiment  200  of the present invention. 
           [0017]      FIG. 9  is a sectional view of embodiment  200  of the present invention. 
           [0018]      FIG. 10  is a sectional view of embodiment  200  of the present invention. 
           [0019]      FIG. 11  is an exploded view of embodiment  300  of the present invention. 
           [0020]      FIG. 12  is a sectional view of embodiment  300  of the present invention. 
           [0021]      FIG. 13  is a sectional view of embodiment  300  of the present invention. 
           [0022]      FIG. 14  is a perspective view of collet  53 ′ of the present invention. 
           [0023]      FIG. 15  is a perspective view of assembly  200 ′ of the present invention. 
           [0024]      FIG. 16  is an exploded view of embodiment  400  of the present invention. 
           [0025]      FIG. 17  is a sectional view of embodiment  400  of the present invention. 
           [0026]      FIG. 18  is a sectional view of embodiment  400  of the present invention. 
           [0027]      FIG. 19  is a sectional view of embodiment  400 ′ of the present invention. 
           [0028]      FIG. 20  is an exploded view of embodiment  500  of the present invention. 
           [0029]      FIGS. 21 and 22  are enlarged perspective views of sleeve  211  of the present invention. 
           [0030]      FIG. 23  is a sectional view of embodiment  500  of the present invention. 
           [0031]      FIG. 24  is a sectional view of embodiment  500  of the present invention. 
       
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
       [0032]      FIGS. 1-2  illustrates embodiment  100  of the present invention comprising of a main shaft  2  where a spring support  2   a,  a hog ring groove  3 , a set of retainer arm recesses  4 , a pair of axel aperture  5 , a upper support land  6 , a pilot bit recess  7 , a spud  8  and a set of keys  9  are all elements of main shaft  2 , a set of axels  10  which are positioned concentrically within axel apertures  5 , a set of retainer arms  11  where a axel aperture  12 , a catch  13 , a ramped surface  14 , a stop ring interface  15 , and a lever interface  16  are all elements of retainer arms  11  and where retainer arms  11  are positioned within recesses  4  and pivotably connected to axel  10 , a upper support  17  where a hog ring recess  18 , a set of spring recesses  19 , a pair of engagement pins  20  and a set of keyways  21  are all elements of upper support  17  and where upper support  17  is concentrically positioned about shaft  2  such that the underside of support  17  is in contact with land  6  and keys  9  are engaged with keyways  21  such that rotation of support  17  relative to shaft  2  is substantially restricted, a set of return springs  22  positioned within spring recesses  19  where the spring force is constantly urging the lower section of arms  11  against shaft  2 , a release sleeve  23  where a stop ring  24  and a washer land  25  are all elements of release sleeve  23  and where sleeve  23  is positioned concentrically about shaft  2 , a set of lever arms  31  where a retainer arm interface  32  and a stop ring interface  26  are all elements of lever arms  31  and where lever arms  31  are positioned within recesses  4  such that interface  32  interacts with interface  16  and interface  26  interacts with the underside of stop ring  24 , a washer  27  positioned concentrically about shaft  2  such that the upper side of washer  27  interacts with washer land  25 , a return spring  28  positioned such that it is contact with spring support  2   a  and washer  27  where the spring force is constantly urging sleeve  23  against upper support  17 , a hog ring  30  that interacts with groove  3  and recess  18  such that in conjunction with land  6  support  17  is substantially rigidly connected to shaft  2  and a set of rubber bumpers  29  positioned concentrically about shaft  2  and located on the upper side of support  17 . 
         [0033]      FIG. 3-5  is a sequence of views that illustrate the present invention in operation. In  FIG. 3  embodiment  100  is in the starting position where return springs  22  are forcing the lower section (section below arms  11  pivot point) of retainer arms  11  against shaft  2 . Note that retainer arms  11  are locked in the position shown as shaft  2  restricts rotation in one direction and the interaction of stop ring  24  with interface  15  restricts rotation in the other direction. Also, in the absence of an external force acting on sleeve  23 , stop ring  24  will remain in the position shown (restricting retainer arms  11  rotation) as spring  28  is urging release sleeve  23  against upper support  17 . In  FIG. 4  the user has pulled release sleeve  23  downward and as a result, the interaction between interface  26  with stop ring  24  has caused lever arms  31  to rotate. This rotation of lever arms  31  in turn rotates retainer arms  11  due to the interaction of interface  32  on lever arms  31  with interface  16  on retainer arms  11 . The user is now able to mount a saw bit  35  (now possible as catch  13  is no longer protruding past the surface of spud  8 ) by positioning spud  8  within the central hole located on saw bit  35  and then rotating (while applying slight downward pressure) saw bit  35  until the pair of engagement pin holes on saw bit  35  align with engagement pins  20  at which point saw bit  35  will slide further down spud  8  until the rear surface of bit  35  comes into contact with and slightly compresses rubber bumpers  29 . The user then releases sleeve  23  where springs  22 / 28  will return the assembly to the initial position as shown in  FIG. 5  where now catch  13  on lever arms  11  retain bit  35  in the position shown. In order to remove bit  35 , the user will again pulls down on sleeve  23  where as discussed before, the assembly will return to the position shown in  FIG. 4  allowing bit  35  to be removed. It should be noted that rubber bumpers  29  are not essential to the design as bit  35  would still be retained in their absence. The purpose of bumpers  29  is to provide the assembly with a predetermined amount of compliance such that saw bits with varying thicknesses of back plates from different manufactures would not have any excessive play (rattle) when mounted to the present invention. This function could be provided for by other obvious means such as a pin and spring combination, a spring positioned concentrically about spud  8 , elastomeric washers, elastomeric O-rings, etc. 
         [0034]    There are many other means of rotating the lever arms disclosed above. For example, if the retainer arms  11  pivot point were moved to a point below stop ring  24 , a simple ramped surface placed on arms  11  could interact with stop ring  24  to rotate the lever arms radially inward when the outer sleeve is pulled downward. In general there are numerous mechanism known in the art that could be used to move/rotate a set of retainer arms. 
         [0035]      FIG. 6  illustrate embodiment  200  of the present invention where the primary difference from embodiment  100  is the use of a set of retainer arms connected at their base that slide rearward to provide the saw bit retention means. In detail embodiment  200  comprises a main shaft  40  where a key  41 , a catch aperture  42 , a spud  43  and a spring land  44  are all features of shaft  40 , a catch pin  46 , a catch pin spring  47  positioned concentrically within aperture  42  such that one end abuts main shaft  40  and the other abuts catch pin  46  such that it urges pin  46  radially outward, a upper support  47   a  where a catch groove  48  that interacts with catch pin  46  such that when pin  46  is engaged with groove  48  upper support  47   a  is unable to move in the axial direction relative to shaft  40 , a keyway  49  that interacts with key  41  such that movement of upper support  47   a  relative to shaft  40  is substantially limited to the axial direction of shaft  40 , a release button aperture  50 , a circlip groove  51 , a groove  62 , and a pair of engagement pins  66  are all features of upper support  47   a,  a release button  52  that is positioned concentrically within release button aperture  50  and intermittently interacts with catch pin  46  such that when catch pin  46  is engaged with catch groove  48 , pressing release button  50  radially inward disengages catch pin  46  from catch groove  48 , a collet  53  where a set of retainer arms  54 , and a set of catches  55  are all features of collet  53 , a O-ring  56 , a circlip  57  that retains collet  53 , a release sleeve  58  where a release ramp  59  that interacts with release button  50 , and a groove  60  are all features of release sleeve  58 , a hog ring  61  that interacts with groove  60  and groove  62  such that movement of release sleeve  58  relative to upper support  47   a  is substantially limited to rotation, a stop pin  63  rigidly fixed to upper support  47   a  that interacts with key  41  to limit the movement of support  47   a  relative to shaft  40  and a main spring  64  positioned concentrically about shaft  40  such that one end is in contact with spring land  44  while the other end contacts upper support  47   a.    
         [0036]      FIG. 7-10  is a sequence of views that illustrates embodiment  200  of the present invention in operation. Starting with  FIG. 7  embodiment  200  is in the starting position where main spring  64  has urged upper support  47   a  into the forward position shown. Note that since spud  43  is only partially inserted into collet  53 , retainer arms  54  are able to bend radially inward. It would also be possible to configure collet  53  such that retainer arms  54  were, to some degree, preformed such that they are bent radially inward in the position shown (as in  FIG. 8 ). Now focusing on  FIG. 8 , the user is mounting saw bit  65  by aligning the center aperture of bit  65  with collet  53  and applying downward pressure while at the same time rotating bit  65  until engagement pins  66  align with their matching apertures on bit  65 . As shown, this downward force in conjunction with the interaction of the ramped section of catches  55  with the edge of the saw bit  65  center aperture has bent the retainer arms  54  radially inward as shown. In  FIG. 9 , the user has continued to apply downward pressure resulting in the position shown where the retainer arms  54  are fully inserted in bit  65  and the back of bit  65  is in contact with upper support  47   a.  In  FIG. 10  the user has continued to apply downward pressure, forcing upper support  47   a  downward relative to shaft  40  to the point where catch pin  46  is engaged with catch groove  48 . The user may now release saw bit  65  as the assembly will remain in the position shown until catch pin  46  is disengaged. In addition, since spud  43  is fully inserted into collet  53 , retainer arms  54  are no longer able to bend radially inward where catches  55  will retain saw bit  65  in the position shown. To remove saw bit  65 , the user rotates release sleeve  58  where due to the interaction between ramp  59 /button  52 , release button  52  is pressed radially inward. This disengages catch pin  46  from groove  48 , allowing spring  64  to return the assembly into the position shown in  FIG. 8  where the saw bit  65  may be removed. It should be noted that it would be possible to configure embodiment  200  such that the user interacts with release button  52  directly, in which case release sleeve  58  would no longer be needed. In general release sleeve  58  is a convenience feature as it removes the need to hunt for or find release button  52 . Main spring  64  is a convenience feature as well as it only serves to minimize user interaction with the assembly in the engagement/disengagement process (the user does not have to physically move upper support  47   a ), where its absence would result in obvious changes in this engagement/disengagement process. Finally, another non-essential element is O-ring  56  which only serves to provide compliance such that saw bits with varying thicknesses of back plates will mount onto embodiment  200  without any excessive play which can result in a rattling sound that could possibly annoy the user. This function could be provided for in many other different ways as discussed in embodiment  100 . 
         [0037]      FIG. 11  illustrate embodiment  300  of the present invention, where the primary difference from embodiment  200  is that the saw bit retention member is the only member that slides forward in the disengaged position. Another difference is the use of a rotating member to lock the saw bit retention member in the engaged/rearward position. In detail, embodiment  300  comprises main shaft  70  where a collet recess  71 , a spud  72 , a spring recess  73 , a pair of engagement pins  74 , a upper support surface  75 , a circlip groove  76  and a set of retainer shaft apertures  77  are all elements of main shaft  70 , a collet  78  where a set of retainer arms  79 , a set of catches  80  positioned at the proximal end of arms  79 , a set of retainer shafts  81  that slidably interact with apertures  77 , a set of retainer grooves  82  and a set of stop washer grooves  83  are all elements of collet  78 , a main spring  84  positioned concentrically about spud  72  such that one end is in contact with spring recess  73  and the other against collet  78  where the spring force is urging collet  78  away from shaft  70 , a set of stop washers  85  that interact with grooves  83  and serve to limit the movement of collet  78 , a locking plate  86  where a set of keyholes  87  that interact with shafts  81  and grooves  82  such that when the narrow section of keyholes  87  are engaged with grooves  82  collet  78  is held substantially fixed relative to shaft  70 , a set of notches  88 , a center aperture  89  and a set of ramped surfaces  90  are all elements of locking plate  86 , a release sleeve  91 , where a set keys  94  that interact with notches  88  such that sleeve  91  is unable to rotate relative to locking plate  86  is an element of release sleeve  91 , a torsional return spring  92  positioned concentrically about shaft  70  such that one end is fixed to locking plate  86  and the other fixed to shaft  70  where the spring force is urging locking plate  86  into the engaged position (narrow section of keyholes  87  engaged with groove  82 ) and a circlip  93  that interacts with circlip groove  76  that retains the position of release sleeve  91  relative to shaft  70 . 
         [0038]      FIG. 12-13  illustrate embodiment  300  of the present invention in operation. Due to the similarities between embodiment  200  and embodiment  300  a full set of operational figures are not required as many steps are obviously similar. Starting with  FIG. 12  embodiment  300  is restrained in the starting position as the narrow section of keyholes  87  is engaged with grooves  82  on shafts  81 . In  FIG. 13 , release sleeve  91  has been rotated which in turn has rotated locking plate  86  due to the interaction of keys  94  with notches  88 . As a result, the narrow section of keyholes  87  have been rotated away from and disengaged with grooves  82  allowing spring  84  to urge collet  78  into the forward position as shown. At this point and similar to the situation in  FIG. 8-9  of embodiment  200 , the user is able to mount the saw bit onto collet  78  where further downward pressure will again align grooves  82  with keyholes  87 . This alignment will then allow spring  92  to rotate locking plate  86  such that the narrow section of keyholes  87  is re-engaged with grooves  82  returning the assembly to the position shown in  FIG. 12 . The ramped surface  90  surrounding the narrow section of keyholes  87  is an optional feature that utilizes a simple wedge mechanism to draw collet  78  further downward during engagement of the narrow section of keyholes  87  with grooves  82  such that any excessive play between upper support surface  75  and the saw bit is substantially minimized. 
         [0039]      FIG. 14-15  illustrates an alternative collet and spud configurations. In  FIG. 14  collet  53 ′ is comprised of a set of retainer arms  54 ′, a set of catches  55 ′ located at the end of arms  54 ′ and a set of rear protruding interfaces  60 ′ located opposite catches  55 ′. The difference interface  60 ′ provides is that when matched with a spud that comprises a depressions of a similar shape such as a chamfer, the distance collet  53 ′ must travel before retainer arms  54 ′ are allowed to bend fully inward is minimized. Specifically, the base of retainer arms  54 ′ at  56 ′ need only travel to the proximal edge of the spud depression to allow for full radially inward movement as opposed to the distal edge or tip of the spud as in previous collet embodiments. Of course if collet  53 ′ were used with a spud without a similar depression as in previous embodiments, the interaction of interface  60 ′ with the distal end of the spud would expand retainer arms  54 ′ radially outward as collet  53 ′ is drawn downward around the spud.  FIG. 15  illustrates an alternative collet and spud assembly  200 ′ comprising of a main shaft  40 ″ where a spud  43 ″ and ramped interfaces  44 ″ are elements of main shaft  40 ″ and a collet  53 ″ that further comprises a set of retainer arms  54 ″ and rotating keys  55 ″. The difference between previous embodiments is that rotational as opposed to downward movement of collet  53 ″ provides the saw bit retention means. Specifically, the interaction of arms  54 ″ with interfaces  44 ″ as collet  53 ″ is rotated expands arms  54 ″ outward. 
         [0040]    In general there are many other embodiments that could be derived from the disclosed elements and features. For example, embodiment  400  of the present invention, shown in  FIGS. 16-19 , utilizes a set of individual retainer arms as in embodiment  100  that comprise a feature substantially similar to interface  60 ′ and are slid rearward as in embodiment  200  and locked into the engaged position via a rotational mechanism as in embodiment  300 . In detail ( FIG. 16-18 ) embodiment  400  includes a main shaft  110  where a circlip groove  111  and a pilot bit aperture  112  are all features of main shaft  110 , and a circlip  113  is seated in groove  111  with a washer  114  positioned against circlip  113 . An aperture  115  with a shape substantially similar to the exterior shape of shaft  110  and a spring catch  116  are all features of washer  114 . An upper support  117  is fixed rigidly to shaft  110  and receives shaft  110  through aperture  120 . The upper support  117  includes a set of retainer arm recesses  118 , a set of recess edges  119 , a locating hub  121  and a set of engagement pins  122 . An outer sleeve  123  is secured between upper support  117  and washer  114  such that movement of outer sleeve  123  is substantially restricted to rotation. The upper support  117  includes a washer recess  124 , and a hub recess  125  in sleeve  123  interacts with hub  121  to position sleeve  123  concentrically about shaft  110 . A release ramp  126  is formed in sleeve  123 , and a set of engagement keys  127  extend inwardly into the central bore of the sleeve  123 . A wedge interface  128  and a spring recess  129  are provided on keys  127 . A set of retainer arms  130  are positioned within and slidably interact within recesses  118 , each arm  130  including a spring notch  131 , and a bearing surface  132  that interacts with engagement keys  127  and release ramps  126  when the sleeve  123  is rotated, as detailed below. A catch  133  extends radially outwardly from the distal end of each arm  130 , and a pivot protrusion  134  extends radially inwardly from the proximal end of each arm  130 . An obliquely tapering surface  135  with a distal vertical wall portion  136  are all features of retainer arms  130 , as best shown in  FIG. 17 . A torsion spring assembly  140  is provided, interacting with spring catch  116  to rotate sleeve  123  such that spring  140  is constantly urging engagement keys  127  against retainer arms  130 . A set of retainer springs  137  is also provided, comprised of leaf springs configured such that one end is fixed to upper support  117  while the other interacts with spring notches  131  of retainer arms  130  such that springs  137  are constantly urging retainer arms  130  radially inward and forward. 
         [0041]      FIG. 17-18  illustrate embodiment  400  in the engaged and disengaged position, respectively. Now focusing on  FIG. 17  embodiment  400  is in the engaged/starting position where retainer arms  130  are restrained from moving upward as spring  140  is urging engagement keys  127  against notch  132 . In  FIG. 18  outer sleeve  123  has been rotated to the point where engagement keys  127  are no longer engaged or in contact with notch  132 . As a result spring  131  has urged retainer arms  130  into the forward position shown. Note that since spring  131  is urging retainer arms  130  both forward and radially inward, edge  119  will be substantially in contact with surfaces  135 / 136  during this forward movement. Still focusing on  FIG. 18 , in this position the user is able to mount the saw bit where similar to previous embodiments once the back of the saw bit is in contact with retainer arms  130 , further downward movement will again align engagement keys  127  with notch  132 , allowing spring  131  to return embodiment  400  to the position shown in  FIG. 12 . Similar to ramped surfaces  90  in embodiment  300 , wedge interface  128  is an optional feature that serves to draw retainer arms  130  further downward after engagement of keys  127  with notch  132 . The release ramps  126  are another optional feature that addresses the situation where due to fouling or friction between the pilot bit and wooden plug (both not shown), retainer arms  130  may become stuck in the engaged position. In this case the interaction of ramps  126  with notches  132  will raise arms  130  to the point where keys  127  are no longer aligned with surfaces  132 , allowing the user to simply pull off the saw bit. 
         [0042]    There are many other possible embodiments of the present invention. For example, springs  137  could be replaced with a set of springs as shown in  FIG. 19  where springs  150  urge the retainer arms  130 ′ radially inward and spring  160  urge retainer arms  130 ′ upwardly. Another possible embodiment would be to reconfigure the retainer arms  130  such that they expanded a hog ring or washer to provide the bit retention means as opposed to the catches illustrated in previous embodiments. Yet another possible embodiment would be to reconfigure embodiment  400  such that engagement keys  127  moved radially inward into notches  132  (similar to embodiment  200 ) or conversely if notches  132  moved radially outward to engage keys  127 . Still yet another possible embodiment would be to integrate a bit retention means with the mandrel&#39;s pair of engagement pins as opposed to the center spud. Finally, other possible embodiments would be the use of ball bearings, expanding washers, pins, etc., as a saw bit retention means. In particular, the use of ball bearings as a means of quick disconnect/connect retention is well known in the art. Also, it should be noted that the disclosed figures are used to illustrate the interoperability of the described elements. In actual production obvious changes would have to be made to allow for both manufacture and assembly. 
         [0043]    In a further embodiment, shown in  FIGS. 20-24 , assembly  500  works in substantially the same way as embodiment  400 ,  400 ′. The minor differences being the following: the use of three retainer arms  200  as opposed to a pair of retainer arms  130  in previous embodiments, where retainer arms  200  no longer include notch  132  in embodiment  400 ,  400 ′. It should be noted that the number of retainer arms used is not a specific requirement of the present invention. For example, other embodiments could be comprised of 1, 2,3,4,5, etc.. retainer arms. The present invention only requires that it includes at least one retainer arm. Also note, the geometry defined by notch  132  in embodiment  400  is not a requirement of retainer arms  130 . The only requirement is that the retainer arms of the present invention include a proximal surface of notch  132  such as bearing surface  201  in embodiment  500  that interacts with the underside of engagement keys  127 ,  203  or optionally wedged interfaces  204 , similar to surfaces  128 , to restrain retainer arms  130 ,  200  in the engaged position  FIG. 17, 23 . The other two remaining sides of notch  132  are optional. For example, if optional release ramp  126  in embodiment  400  was present, then the distal surface of notch  132  would be required. 
         [0044]    Another optional improvement includes the use of a single spring  205  to provide both the rotational and axial spring force previously provided by spring  140 . In detail, spring  205  comprises hook  206  on the proximal end of spring  205  that engages spring catch  207  on washer  208  and pin feature  209  on the distal end that engages and slidably interacts with corner  210  as shown in  FIG. 23 . Due to this slidable interaction between corner  210  and pin feature  209 , the distal end of spring  205  is able to move freely in the axial direction and provide a axial spring force to retainer arms  130  while also transferring a rotational spring force to corner  210  on outer sleeve  211 . Again, note that the rotational and axial force components of spring  205  are optional. For example, the rotational force component of spring  205 ,  131  serves to automatically lock retainer arms  201 ,  130  in place when bearing surface  201  is moved proximally past the underside of keys  203  or wedge interface  204 . However, this is a convenience feature as the user could manually rotate outer sleeve  211  when the above condition is met. Similarly, the axial component of spring  205  serves to automatically eject a hole saw bit and hold retainer arms  200  in the position shown in  FIG. 24 . This is also a convenience feature as the user may easily pull off the hole saw bit manually and there are many other ways to restrain retainer arms  200  in the position shown in  FIG. 24 . For example, magnets, detents, etc. may be used; if optional side springs  150  are used they would also assist in holding retainer arms  130  in the position shown in  FIG. 24 . In addition, holding or placing the retainer arms in the position in  FIG. 24  could be done manually as well. 
         [0045]    Another optional improvement in embodiment  500  is the use of a rubber o-ring  213  to provide a degree of compliance that will more easily allow the user to tighten outer sleeve  211  when any embodiment is comprised of wedged interfaces  204 . In detail, o-ring  213  is located between proximal face of upper support  214  and wear washer  215  positioned against washer lands  216 . As shown in  FIG. 23 , in this configuration any rotational tightening torque applied to outer sleeve  211  will force bearing surfaces  201  further up the ramps of wedge interface  204  which in turn will force/draw outer sleeve  211  towards upper support  214  compressing o-ring  213 . This compression of o-ring  213  provides the optional compliance; such methods and systems are well known in the art. It should be noted that the present invention does not specifically require a rubber O-ring, any number of compliance members could provide the same function such as a spring, Bellville washer, elastomeric compounds of many different shapes, etc. 
         [0046]    Yet another optional improvement in embodiment  500  is to reconfigure the shape of pilot bit aperture  112  in embodiment  400 ,  400 ′ as illustrated in pilot bit aperture  217 . In detail, pilot bit aperture  217  is comprised of a plurality of retainer faces  218  that are arranged substantially parallel to and preferably of substantially the same shape of surface  219  on retainer arms  200 . For example, for a surface  219  that was substantially flat, retainer faces  218  would be substantially flat and parallel (in the engaged position  FIG. 23 ) to surface  219 . Also note, that while the shape of pilot bit aperture  217  is illustrated as substantially triangular, this is a result of embodiment  500  illustrated with three retainer arms  200  and is not a requirement. For example, if embodiment  500  comprised of four retainer arms  200  then the shape of pilot bit aperture  217  would be substantially square. The advantage of this configuration is the ability to use pilot bit  250  with a proximal end of substantially the same shape as pilot bit aperture  217 . This will allow surface  219  to extend farther radially inward and therefore increase the total radially outward throw of the distal end of retainer arms  200  when moving from the disengaged position illustrated in  FIG. 24  to the engaged position illustrated in  FIG. 23 . 
         [0047]    While the foregoing written description of the invention enables one of ordinary skill to make and use what is considered presently to be the best mode thereof, those of ordinary skill will understand and appreciate the existence of variations, combinations, and equivalents of the specific embodiment, method, and examples herein. The invention should therefore not be limited by the above described embodiment, method, and examples, but by all embodiments and methods within the scope and spirit of the invention.