Abstract:
A router mounting system is disclosed. A preferred embodiment of the router mounting system includes a router assembly, a first sub-base, and a router table. The router assembly and first sub-base include interlocking radial projections, recesses and discontinuities such that the first sub-base can be firmly attached to the router assembly quickly and without the use of tools or fasteners. This allows a user to interchangeably use a single router either in the hand mode of operation or in the table mode of operation with only a few seconds required to change betweens modes of operation.

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
   This application claims priority from U.S. Provisional Application Ser. No. 60/506,993, filed Sep. 29, 2003. 

   BACKGROUND 
   1. Field of Invention 
   This invention relates in general to routers as used in the field of woodworking and, more particularly, to a system for mounting a router to a router table. 
   2. Description of Prior Art 
   The router is among the most versatile of woodworking tools. When fitted with a cutting tool, or router bit, and properly guided, it can be used to cut rabbets, dados, mortises, tenons and to perform a variety of other wood shaping operations. A number of accessories are available to make these cuts safer and easier to perform. Perhaps the most versatile of these accessories is the router table. A router table allows for mounting an inverted router below the work surface of the table. An opening in the table allows the router bit to protrude above the work surface. The work piece can then be brought into contact with the spinning bit to make the desired cut. 
   The major components of a router are a motor with bit receiving collet, a base and a sub-base. In order to mount a router to a router table, the prior art requires that the router be inverted and the fasteners securing the router sub-base to the router base be removed. These fasteners are typically machine screws and require the use of a tool such as a screwdriver or a hex key type wrench for removal. The sub-base is then set aside. The inverted router is then held in place beneath the work surface of the router table, and the mounting holes in the table are aligned with the mounting holes in the router base. Fasteners and an appropriate tool are then used to secure the router to the router table. It should be noted that the sub-base mounting screws are typically not long enough to serve as the router-to-table mounting screws due to the difference in thickness between the router sub-base and the router table top, and therefore additional longer screws must be obtained. It should also be noted that, once the router is secured to the table, the installation process must be reversed and the sub-base re-attached to use the router in the hand mode of operation again. It should be appreciated that the above process is somewhat difficult, time consuming and requires the use of tools and fasteners. 
   SUMMARY OF THE INVENTION 
   It is an object of this invention to provide an improved system for quickly attaching a router to a router table. In a preferred embodiment, this is accomplished without the use of tools. 

   
     BRIEF DESCRIPTION OF THE DRAWINGS 
       FIG. 1  is a front perspective view of a router and router table assembly made in accordance with the present invention; 
       FIG. 2  is an exploded front perspective view of the assembly of  FIG. 1 ; 
       FIG. 3  is an exploded front view with partial section of the router shown in  FIG. 1  but inverted for manual operation; 
       FIG. 4  is an exploded front perspective view of the router of  FIG. 3 ; 
       FIG. 5  is a front perspective view of a second embodiment of a router table made in accordance with the present invention; 
       FIG. 6  is an exploded front perspective view of a router for use with the table of  FIG. 5 ; 
       FIG. 7  is another exploded front perspective view of the router of  FIG. 6 ; 
       FIG. 8  is a bottom perspective view of a router table drop-in plate made in accordance with a further embodiment of the present invention; and 
       FIG. 9  is a bottom perspective view of a router table made in accordance with a further embodiment of the present invention. 
   

   DESCRIPTION OF THE PREFERRED EMBODIMENTS 
     FIGS. 1–4  show a first embodiment of a router table  24  and a router assembly  12 . The router assembly  12 , shown best in  FIGS. 3 and 4 , includes a motor  14 , a bit receiving collet  16 , a base  18 , and a first sub-base  20 . The router table  24  includes a second sub-base  22 , shown in  FIG. 2 , which is very similar to the first sub-base  20 . In this preferred embodiment, the motor  14  rotates the bit receiving collet  16  about a central axis  26 . 
   The base  18  includes a circular plate  28  having a first periphery  30  and defining a first opening  32  aligned with the central axis  26 . The base also has a planar top surface  34  normal to the first periphery  30  and central axis  26 . The first periphery  30  of the base  18  has an internal surface which communicates with the central opening  32  and defines a plurality of radially directed recesses  36 . In this preferred embodiment, these radially directed recesses  36  are in the form of heavy load bearing threads, in this case a stub acme style thread. In this case, the thread is a multiple start thread to facilitate rapid assembly of components. The radially directed recesses  36  in the base  18  are recessed from their respective radially-directed lips  37 , which have a smaller inside diameter than the recesses  36 . The recesses  36  and lips  37  are discontinuous and are spaced apart by the discontinuities  38  (see  FIG. 2 ), which have an inside diameter at least as great as the inside diameter of the recesses  36 . 
   The first sub-base  20  includes a second periphery  40  and defines a second opening  42  aligned with the central axis  26 . The first sub-base also includes planar top and bottom surfaces  44 ,  46 , which are normal to the second periphery  40  and central axis  26 . The second periphery  40  includes a plurality of radially outwardly-directed projections  48 . The first sub-base  20  further defines discontinuities  50  between the radially directed projections  48 , such that the first sub-base  20  may be fully axially inserted into the base  18 , with the projections  48  of the sub-base  20  aligned with the discontinuities  38  in the base  18 , and then the sub-base may be axially rotated so that the radial projections  48  of the sub-base  20  engage the radial recesses  36  of the base  18 , thereby mounting the base  18  and first sub-base  20  together. It should be understood that while a heavy, load bearing, multiple start thread is used in this preferred embodiment, radial recesses  36  and radial projections  48  may be of square, rectangular, circular or other cross-section and do not require a thread lead angle to mount base  18  and first sub-base  20  together. Also, while it is preferred that there be external projections on the sub-base and internal recesses on the base to receive those projections, it is understood that the projections could be on the base and recesses on the sub-base, and so forth, as long as the two members mate in a quick-connect manner. 
   As shown in  FIG. 3 , the planar bottom surface  46  of the first sub-base  20  serves as a substantially flat working surface perpendicular to the central axis  26 . When the base  18  and first sub-base  20  are assembled for operation, the sub-base  20  provides a peripheral surface adjacent to the working surface  46  that is substantially smooth and continuous, so it can function as a guide surface for guiding a workpiece. As shown in  FIGS. 2 and 3 , the radial projections  48  on the first sub-base  20  and second sub-base  22  lie at an angle to an imaginary horizontal plane perpendicular to the central axis  26 , so they function as screw threads, guiding the respective sub-base  20  or  22  to move in the direction of the central axis  26 , toward and away from the base  18  as the radially directed projections  48  of the respective sub-base  20  or  22  rotate into and out of their respective recesses  36  in the base  18 . 
   This preferred embodiment further includes a means for locking the base  18  and first sub-base  20  together to ensure against counter-rotation and undesired disassembly of the components during use. In this preferred embodiment, the locking is accomplished by use of a spring biased pin  52  disposed on the top planar surface  34  of the base  18 . The spring biased pin  52  projects through the top planar surface  34  of the base  18  in a direction parallel to the axis  26  and engages a pin-receiving receptacle  54  in the first sub-base  20 , thereby preventing rotation of the first sub-base  20  relative to the base  18  once those members have been assembled. In this preferred embodiment, the number of pin receiving receptacles  54  is equal to the number of radially directed recesses  36  and to the number of radially directed projections  48  in the base  18  and the first sub-base  20 , respectively. This arrangement allows assembly and locking of the components at any position in which the projections  48  can engage the recesses  36  and does not require special angular orientation of the sub-base  20  relative to the base  18 . 
   Since the locking pin  52  and receptacle  54  are internal to the peripheries of the base and sub-base, the locking mechanism is shielded from any dust and chips that may be created when the router is operating. This is also the case with the spring-biased ball locking mechanism in the second embodiment, which will be described later. 
   Referring now to  FIG. 2 , the router table  24  defines a third opening  56 , and the second sub-base  22  defines a fourth opening  58 , wherein both openings  56  and  58  are aligned with the central axis  26 . The second sub-base  22  is substantially similar to the first sub-base  20  but includes additional means for mounting the sub-base  22  to the router table  24 . In this preferred embodiment, these means include a plurality of threaded holes  60  in the sub-base and a corresponding plurality of fasteners  62 , which extend through openings  63  in the table  24  and are threaded into the threaded holes  60 . The fasteners  62  may be common machine screws. It should be appreciated that, once the second sub-base  22  is assembled to the router table  24 , it is not necessary to remove the second sub-base  22  from router table  24  for any reasons associated with normal router and router table use. The second sub-base  22  includes projections  48  that are identical to the projections  48  of the first sub-base  20 , which permits the router base  18  to be attached to, or removed from, the second sub-base  22 , in order to mount the router  12  onto or remove it from the router table  24 . It should also be appreciated that the second sub-base  22  alternatively may be formed integral with a common router table drop-in plate  64 , as shown in  FIG. 8 , or it may be formed integral with a router table top  66 , as shown in  FIG. 9 . 
   As can be seen in  FIGS. 1 and 2 , the table  24  provides a substantially flat working surface. When the base  18  is assembled to the second sub-base  22 , the base  30  is entirely recessed below the working surface of the table  24 . The locking pin  52  and receptacle  54  are shielded from the working surface of the table  24  by being located beneath the table  24  and internal to the assembly. 
   Operation of the First Preferred Embodiment 
   For the hand mode of router operation, the first sub-base  20  is assembled to the router assembly  12 . This is accomplished by aligning the first sub-base  20  with the router assembly  12 , so that the projections  48  of the sub-base are aligned with the discontinuities  38  of the base  30 , then moving the first sub-base  20  axially toward the base  18  until the projections  48  of the first sub-base  20  are aligned with the recesses  36  of the base  30 . Then, the first sub-base  20  is rotated relative to the base  18 , so the projections  48  of the sub-base enter the recesses  36  of the base  30 , and then the spring biased locking pin  52  reaches one of the pin receiving receptacles  54  in the first sub-base  20  and projects into that receptacle  54 , locking the members together. The first sub-base  20  is now securely assembled to the router assembly  12 , and the router assembly  12  may now be used in the normal hand mode of operation. 
   For the router table mode of operation, the first sub-base  20  is removed from the router assembly  12 , and the router assembly  12  is mounted to the router table  24 . This is accomplished by first disengaging the spring biased locking pin  52 , then rotating the first sub-base  20  relative to base  18  in the opposite direction from the direction that was used for assembly, and then axially withdrawing the first sub-base  20  from the base  18 . The first sub-base  20  is then set aside. The router assembly  12  is then inverted and axially aligned with the second sub-base  22 , which has already been secured to the underside of the router table  24  with fasteners  62  as previously described. The router assembly  12  is then axially inserted upwardly into the second sub-base  22 , is rotated about the axis  26 , and is then locked into position when the spring biased pin  52  engages one of the pin receiving receptacles  54  in the second sub-base  22 . The router assembly  12  is now securely assembled to the second sub-base  22  and thus to the router table  24  and is now ready for the router table mode of operation. The sub-base  20  easily can be removed from the base  18  of the router assembly  12  without the use of tools or fasteners in only a few seconds. The router assembly  12  then can be attached to the router table  22  without the use of tools or fasteners, again in only a few seconds. 
   Description of Second Embodiment 
   The first preferred embodiment described above is best suited for new production of routers, wherein the radially directed recesses  36  are formed into the base  18  of the router assembly  12  during production. A second preferred embodiment, shown in  FIGS. 5–7 , may be used with prior art routers which have standard bases without any means for receiving a first sub-base  20  or second sub-base  22 . 
   This embodiment includes a router assembly  112 , including a motor  114  and bit receiving collet  116 , a base  118 , a base adapter  118   a  and a first sub-base  120 . There is also a second sub-base  122  and a router table  124 . In this embodiment, the motor  114  rotates the bit receiving collet  116  about the central axis  126 . The base  118  includes a plurality of threaded mounting holes  180 , which are part of the original manufacture of the router. The base adapter  118   a  includes a circular plate  128  with a first (internal) periphery  130  and a second (external) periphery  130   a  aligned with the central axis  126 . The base adapter also defines a first opening  132 . The base adapter  118   a  also includes first and second planar surfaces  134 ,  134   a  normal to the periphery  130  and central axis  126 . The base adapter  118   a  also defines a plurality of mounting holes  180   a  through the first and second planar surfaces  134 ,  134   a  that align with and are coincident with the threaded mounting holes  180 , permitting the base adapter  118   a  to be assembled onto the base  118  by means of fasteners  180   b . The first periphery  130  of the base adapter  118   a  includes a plurality of radially directed recesses  136 , lips  137 , and discontinuities  138 , which are similar to the recesses  36 , lips  37 , and discontinuities  38  in the first embodiment. The base adapter  118   a  further defines a plurality of pin receiving receptacles  170  extending from its second periphery  130   a  through its first periphery  130 , in a direction that is normal to the central axis  126 . The base adapter  118   a  further defines a plurality of ball-receiving receptacles  154  on its second planar surface  134   a.    
   The first sub-base  120  has a third periphery  140 , and defines a second opening  142  aligned with the central axis  126 . The first sub-base  120  also has a planar surface  144  normal to the third periphery  140  and central axis  126 . The third periphery  140  includes a plurality of radially directed projections  148 , which are received in the recesses  136  of the base adapter  118   a . The first sub-base  120  further includes discontinuities  138  between the radially directed projections  148 , such that the first sub-base  120  may be fully axially inserted into the base adapter  118   a  with the projections  148  aligned with the discontinuities  138  and may then be rotated so that the radial projections  148  engage the radial recesses  136  to mount the base adapter  118   a  and first sub-base  120  together. It should be understood that while a heavy, load bearing, multiple start thread is shown here, the radial recesses  136  and radial projections  148  may be of square, rectangular, circular or other cross-section and do not require a thread lead angle to mount the base adapter  118   a  and first sub-base  120  together. 
   As with the first embodiment, this embodiment includes a means for locking the base adapter  118   a  and first sub-base  120  together to prevent counter-rotation and undesired disassembly of the components during use. This locking is accomplished by use of spring biased balls  152  projecting upwardly from and partially recessed into the planar surface  144  of the first sub-base  120 . These spring biased balls  152  are biased toward the adapter  118   a  by springs (not shown), located in the recesses in the planar surface  144  in which the balls  152  reside. The spring biased balls  152  engage respective ball-receiving receptacles  154  in the base adapter  118   a , thereby preventing unintended rotation of the first sub-base  120  relative to the base adapter  118   a . In this embodiment, the number of spring biased balls  152  and ball-receiving receptacles  154  is equal to the number of radially-directed recesses  138  and to the number of radially-directed projections  148  in the base adapter  118   a  and the first sub-base  120 , respectively. This arrangement allows assembly and locking of the components at any of the openings defined by the projections  148  and discontinuities  138 . 
     FIG. 5  shows a second sub-base  122  that is substantially like the first sub-base  120 , except that it includes means for mounting the second sub-base  122  to the router table  124 . In this embodiment, these means include a plurality of internally-threaded mounting holes  160  used in conjunction with threaded fasteners  162 , which extend through openings  163  in the table  124  and are threaded into the holes  160 . The fasteners  162  may be common machine screws. It should be appreciated that, once the second sub-base  122  is assembled to the router table  124 , it is not necessary to remove the second sub-base  122  from the router table  124  for any reasons associated with normal router and router table use. The second sub-base  122  includes a fourth periphery  166 , defines a third opening  158 , and defines a plurality of pin receiving receptacles  170   a  disposed about the fourth periphery  166  and normal to the central axis  126 . The pin receiving receptacles  170   a  are disposed such that, upon assembly of the base adapter  118   a  to the second sub-base  122 , the pin receiving receptacles  170   a  of the second sub-base  122  and the pin receiving receptacles  170  of the base adapter  118   a  are coaxially aligned. A locking pin  172  (shown in  FIG. 5 ) may then be inserted through an aligned pair of pin receiving receptacles  170  and  170   a  to ensure against counter-rotation and undesired disassembly of the components during use. The router base  118  may easily be attached to, or removed from, the second sub-base  122  and the router table  124 . It should also be appreciated that the second sub-base  122  may be formed integrally with a common router table drop-in plate or may be formed integral with a router table top. 
   Operation of the Second Embodiment 
   Referring again to  FIGS. 5–7 , for the hand mode of router operation, the base adapter  118   a  is assembled to the base  118  by means of industry standard fasteners such as machine screws  180   b  inserted through the mounting holes  180   a  and secured into threaded holes  180 . The base adapter  118   a  then becomes part of the base  118 , and the first sub-base  120  is then assembled to the base adapter  118   a . This is accomplished by axially aligning the first sub-base  120  with the router assembly  112 , with the radially directed projections  148  of first sub-base  120  aligned with the discontinuities  138  of the base adapter  118   a , then axially inserting the first-sub-base  120  into the base adapter  118   a , then rotating the first sub-base  120  relative to the base adapter  118   a  so the projections  148  enter their respective recesses  136 , and subsequently engaging the spring biased locking balls  152  into their respective ball receiving receptacles  154  in the base adapter  118   a . The first sub-base  120  is now securely assembled to the router assembly  112 , and the router may now be used in the normal hand mode of operation. 
   For the router table mode of operation, the first sub-base  120  is removed from the router assembly  112 , and the router assembly  112  is then inverted and mounted to the router table  124 . This is accomplished by first disengaging the spring biased locking balls  152  from their respective ball receiving receptacles  154 , then rotating the first sub-base  120  relative to the base adapter  118   a  and axially withdrawing the first sub-base  120  from the base adapter  118   a . The first sub-base  120  is then set aside. The router assembly  112  is then inverted and is assembled onto the second sub-base  122  in the same manner in which it was assembled onto the first sub-base  120 . The second sub-base  122  already has been secured to the underside of the router table  124  with fasteners  162  as previously described. When the pin receiving receptacles  170  in the base adapter  118   a  align with the pin receiving receptacles  170   a  in the second sub-base  122 , a locking pin  172  is inserted into the aligned pin receiving receptacles  170  and  170   a , thereby preventing reverse rotation. The router assembly  112  is now securely assembled to the second sub-base  122  and thereby to the router table  124  and is now ready for the router table mode of operation. 
   While two preferred embodiments of the invention have been illustrated and described in detail in the drawings and foregoing description, these are to be considered as illustrative and not restrictive in character, it being understood that only the preferred embodiments have been shown and described and that all changes and modifications that come within the spirit of the invention are desired to be protected. 
   The embodiments described above have many advantages over the prior art. It will be noted that alternative embodiments may not include all of the features described yet still benefit from at least some of the features. Those of ordinary skill in the art may readily devise their own implementations of the router mounting system that incorporate one or more of the features of the present invention and fall within the spirit and scope of the present invention as defined by the claims.