Abstract:
A method of changing the distance between a rotary cutter disposed on a carriage assembly and a work surface. The method includes the steps of providing a first mechanism on the carriage assembly for making small distance changes between the rotary cutter and the work surface and providing a second mechanism on the carriage assembly for making larger distance changes between the rotary cutter and the work surface. The user selects one of the first and the second mechanisms to adjust the distance between the rotary cutter and the work surface and then activates the selected one of the first and the second mechanisms. Activation of the second mechanism automatically disengages the first mechanism.

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
       [0001]    This application is a division of U.S. patent application Ser. No. 12/891,171, filed on Sep. 27, 2010, which is a division of U.S. patent application Ser. No. 12/464,248 filed on May 12, 2009, now U.S. Pat. No. 7,810,530, which is a continuation of U.S. patent application Ser. No. 11/401,573 filed on Apr. 10, 2006, now U.S. Pat. No. 7,559,347, the specifications of which are incorporated by reference herein in their entirety. 
     
    
     BACKGROUND OF THE INVENTION 
       [0002]    1. Technical Field 
         [0003]    The invention relates generally to a rotary cutter which is mounted on a work table. More particularly, the invention relates to an assembly for raising and lowering the cutter wherein the assembly allows for rapid, coarse adjustments as well as the fine adjustments. Specifically, the invention relates to such an assembly which includes a lift handle for rapidly raising and lowering the rotary cutter and an adjustment screw for providing the fine adjustments. 
         [0004]    2. Background Information 
         [0005]    Various types of rotary cutters such as routers are known in the art which are mounted on work tables which provide a work surface on which wood or other work materials may be seated during the cutting thereof by the rotary cutter. A variety of mechanisms are known in the art for raising and lowering the rotary cutter with respect to the table or work surface thereof. Such mechanisms include threaded adjusting screws for finely adjusting the height of the rotary cutter. For example, see U.S. Pat. No. 6,505,659 granted to Hummel. Such adjusting screw mechanisms and other fine adjustment mechanisms provide accurate height adjustment but are not capable of rapidly raising and lowering the cutter when coarser adjustments are desired. Thus, there remains a need in the art for such a rapid adjustment assembly which is also suitable for use with a fine adjustment mechanism. 
       BRIEF SUMMARY OF THE INVENTION 
       [0006]    The present invention provides an apparatus comprising a table plate; a carriage assembly disposed beneath the table plate and adapted for supporting a rotary cutter; and a lift handle which is mountable on and extends upwardly from the carriage assembly and extends above the table plate for supporting the carriage assembly during manual raising and lowering of the carriage assembly via the lift handle. 
     
    
     
       BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWINGS 
         [0007]      FIG. 1  is a front elevational view with portions cut away showing the adjustment assembly of the present invention mounted on a table without the lift handle and fine adjustment handle shown. 
           [0008]      FIG. 2  is a side elevational view with portions cut away of the adjustment assembly and table of  FIG. 1 . 
           [0009]      FIG. 3  is a sectional view taken on line  3 - 3  of  FIG. 2 . 
           [0010]      FIG. 4  is a sectional view taken on line  4 - 4  of  FIG. 2 . 
           [0011]      FIG. 5  is a sectional view taken on line  5 - 5  of  FIG. 4 . 
           [0012]      FIG. 6  is a side elevational view similar to  FIG. 2  showing the operation of the fine adjustment handle for providing fine vertical adjustment of the carriage assembly and rotary cutter. 
           [0013]      FIG. 7  is a fragmentary side elevational view similar to  FIG. 2  showing the lift handle moving from an unmounted position toward a mounted position. 
           [0014]      FIG. 8  is an enlarged fragmentary sectional view of a portion of  FIG. 7  from the same perspective as  FIG. 7  showing the lift handle having been inserted into the carriage assembly. 
           [0015]      FIG. 9  is a sectional view taken on line  9 - 9  of  FIG. 8 . 
           [0016]      FIG. 10  is similar to  FIG. 8  and shows the lift handle having been rotated to position the lift handle in a mounted lifting position and to disengage the engaging member from the fine adjustment screw. 
           [0017]      FIG. 11  is a sectional view taken on line  11 - 11  of  FIG. 10 . 
           [0018]      FIG. 12  is a fragmentary side elevational view similar to  FIG. 7  showing the lift handle in the lifting position and illustrating the rapid raising and lowering of the carriage assembly and rotary cutter. 
       
    
    
       [0019]    Similar numbers refer to similar parts throughout the drawings. 
       DETAILED DESCRIPTION OF THE INVENTION 
       [0020]    The adjustment assembly of the present invention is indicated generally at  10  in  FIGS. 1 ,  6  and  12  and includes a lift handle  12  ( FIG. 12 ) and a fine adjustment handle  14  ( FIG. 6 ). Assembly  10  further includes a carriage assembly  16  for mounting thereon a rotary cutter such as a router  18 . Lift handle  12  is configured for the rapid raising and lifting of carriage assembly  16  and router  18  while fine adjustment handle  14  is configured for the fine vertical adjustment of assembly  16  and router  18 . 
         [0021]    Assembly  10  further includes a table plate  20  having an upper work surface  22 . Table plate  20  is mounted on a work table  24  having an upper work surface  26  so that upper surfaces  22  and  26  are substantially coplanar and horizontal. Assembly  10  further includes a support assembly  28  which is mounted on and extends downwardly from table plate  20  and includes an adjustment screw  30  which is elongated in a substantially vertical direction and is rotatable about a substantially vertical axis in order to provide fine vertical adjustment of carriage assembly  16 . Support assembly  28  is described in greater detail in U.S. Pat. No. 6,948,892 granted to Hummel, which is incorporated herein by reference. Handle  14  is also described in further detail in said patent. Assembly  10  further includes first and second guide posts  32  and  34  each having a respective stop  36  disposed adjacent a lower end thereof to limit the travel of carriage assembly  16 , which is slidably mounted on guide post  32  and  34  respectively via first and second bushings  38  and  40 . Router  18  is mounted on carriage assembly  16  so that a rotary cutter bit  42  may extend above upper surface  22  of table plate  20  when in an operational cutting position. Router  18  rotates cutter bit  42  around a substantially vertical axis during operation. 
         [0022]    With reference to  FIG. 2 , carriage assembly includes first and second clamping members  44  and  46  which are connected to one another via a pair of spaced threaded rods  48  on which are threadably mounted a respective pair of threaded handles  50  for tightening and loosening clamping members  44  and  46  about router  18 . 
         [0023]    Referring to  FIG. 3 , a ring member  52  is removably mounted on table plate  20  and defines a central through opening  54  through which router bit  42  extends upwardly of table plate  20 . Ring member  52  may be replaced by an alternate ring member to accommodate different sized cutter bits  42 . In addition, ring member  52  is removable in order to allow router  18  to move upwardly to a position which allows cutter bit  42  to be removed and replaced at a position above table plate  20 . The rapid vertical adjustment provided by lift handle  12  greatly expedites the ability to remove and replace cutter bits.  FIG. 3  also shows a pair of mounting screws  56  for mounting guide posts  32  and  34  on table plate  20 . A cap member  58  is rotatably mounted on table plate  20  and defines a central hexagonal recess  60  adapted to matingly engage a portion of handle  14  for rotation of cap member  60  and adjustment screw  30 . Table plate  20  also defines a through opening  62  which is disposed between and aligned with opening  42  and recess  60  of cap member  58 . A portion of a lift-handle engaging member  64  of carriage assembly  16  is visible through opening  62  and is secured to first clamping member  44  via a mounting screw  66  as shown in  FIG. 4 . 
         [0024]    Referring to  FIGS. 4 and 5 , first clamping member  44  defines a vertically extending opening in which are disposed upper and lower bushings  68  and  70  which define portions of a cylindrical lift-handle-receiving opening  72 . Engaging member  64  includes a projection  74  which extends over a portion of opening  72 . Projection  74  has a flat side  76  disposed above opening  72  and a downwardly facing surface or ledge  78  which is engagable by lift handle  12  so that handle  12  may support carriage assembly  16  during raising and lowering thereof as will be further detailed below. First member  44  further defines a horizontally extending passage  80  which is disposed between bushings  68  and  70  and communicates with the respective portions of openings  72  defined thereby. An adjustment screw engaging member  82  is movably disposed in passage  80  and more particularly is slidable in a horizontal direction therein. Member  82  has a laterally facing flat lift-handle-engaging surface  84  which is vertically aligned with flat side  76  of projection  74 . Member  82  defines a vertically extending through passage  86  for receiving therethrough adjustment screw  30 . Member  82  includes a threaded side or section  88  which bounds passage  86  and is disposed only along one side of adjustment screw  30  for selective engagement therewith. Threaded section  88  of member  82  is spring biased into the engaged position shown in  FIG. 5  by spring members  90  which are disposed in passage  80 . Passage  86  is wider than the outer diameter of adjustment screw  30  so that engaging member  82  may be moved against the spring bias of spring members  90  from the engaged position shown in  FIG. 5  to the disengaged position shown in  FIG. 10 . First clamping member  44  further defines a second vertically extending passage in which are disposed upper and lower bushings  92  and  94  each defining a portion of a vertically extending passage  96  through which adjustment screw  30  passes. Threaded section  88  of engaging member  82  is thus the only portion of carriage assembly  16  which threadably engages adjustment screw  30 . Thus, the threaded engagement between screw  30  and section  88  provides for the fine vertical adjustment of carriage assembly  16  during rotation of screw  30 . 
         [0025]    The operation of assembly  10  is described with reference to  FIGS. 6-12 .  FIG. 6  shows a hexagonal end portion  98  having been inserted matingly into recess  60  of cap member  58  and illustrates the rotation of handle  14  at Arrows A to provide the fine vertical adjustment indicated at Arrows B of carriage assembly  16  and router  18  via the threaded engagements with section  88  of engaging member  82  ( FIG. 5 ). 
         [0026]    Referring to  FIGS. 7-12 , the operation of lift handle  12  to provide rapid vertical adjustment of carriage assembly  16  and router  18  is described.  FIG. 7  shows handle  12  moving downwardly as indicated at Arrow C prior to insertion thereof through opening  62  of table plate  20 . Opening  62  is vertically aligned with handle receiving opening  72  of first clamping member  44  and thus serves to guide handle  12  into opening  72 . Handle  12  has an L-shaped configuration including a straight substantially cylindrical rod  100  and a grip  102  ( FIG. 12 ) which extends outwardly from rod  100  at an upper end thereof. In the operational position of handle  12 , rod  100  is oriented vertically and grip  102  is oriented horizontally. Preferably, handle  12  is an integrally formed one piece member wherein a straight rod is bent to form rod  100  and grip  102 . Rod  100  is tapered adjacent a lower end  104  thereof to facilitate insertion of rod  100  through openings  62  of table plate  20  and  72  of carriage assembly  16 . An arcuate circumferentially extending groove  106  is formed in rod  100  and spaced upwardly from and adjacent lower end  104 . Rod  100  includes a flat surface  108  extending from lower end  104  to groove  106 . 
         [0027]      FIG. 8  shows the lower portion of handle  12  having been inserted into opening  72  so that flat surface  108  of rod  100  is disposed closely adjacent or in abutment with flat surface  84  of engaging member  82  in a substantially coplanar orientation. During insertion of handle  12  into opening  72 , flat side  76  of engaging member  64  serves to align flat surface  108  with flat surface  84 . Groove  106  is bounded by a cylindrical neck  110  which has a diameter which is smaller than that of the portion of rod  100  thereabove whereby rod  100  is stepped between the differing diameter sections to form a downwardly facing annular ledge  112  a portion of which engages the upper surface of projection  74  of engaging member  64  whereby projection  74  serves as a stop to prevent further downward movement of handle  12 . Rod  100  also includes an arcuate lower ledge  114  which faces upwardly and bounds groove  106 . 
         [0028]    Once handle  12  is inserted, it is rotated as indicated at Arrows E in  FIGS. 10 and 11  to move engaging member  82  horizontally in a linear manner as indicated by Arrows F in  FIGS. 10 and 11  to the disengaged position in which threaded section  88  is disengaged from the threads of adjusting screws  30 . Just prior to the disengagement of member  82 , lower ledge  114  of rod  100  is rotated below projection  74  and into engagement with ledge  78  thereof so that handle  12  is ready to support the weight of carriage  16  and router  18  via the engagement of ledges  78  and  114  before carriage assembly  16  is disengaged from adjusting screw  30 . The rotation of handle  12  thus positions projection  74  within groove  106 . It is noted that the threads of threaded section  88  of engaging member  82  lie along the arc of a circle which is less than 180° to ensure the ability for the movement of engaging member  82  to the disengaged position. However, it is desirable to produce threaded section  88  with the greatest arc possible within this limitation to provide sufficient strength and longevity for the threads of engaging member  82 . 
         [0029]    Once the disengaged position has been achieved, handle  12  is raised or lowered as indicated at Arrows G in  FIG. 12  to correspondingly raise and lower carriage assembly  16  and router  18  as indicated at Arrows H. In the disengaged position, carriage assembly  16  is thus vertically slidable with bushings  92  and  94  sliding over adjustment screw  30  and bushing  38  and  40  respectively sliding along guide posts  32  and  34 . In the disengaged position of engaging member  82 , handle  12  is in a fixed vertical relation with carriage assembly  16  and router  18  whereby they all move upwardly and downwardly in unison. While the height of first clamping member  44  is generally kept to a minimum to reduce the weight of assembly  16  while providing sufficient strength therefor, bushings  38  and  40  preferably extend above and below member  44  in order to provide additional stability to the alignment of carriage assembly  16  to minimize frictional engagement with adjusting screw  30  so as to minimize the wear on the threads of screw  30  and of section  88  of engaging member  82 . If replacement of engaging member  82  should be required, it is easily removed via passage  80  once carriage assembly  16  is removed from adjusting screw  30 , as adjusting screw  30  is the only structure which retains engaging member  82  within passage  80  when assembly  16  is removed from router  18 . Similarly, engaging member  64  may be easily removed and replaced via screw  66  if necessary. Engaging member  64  is formed of a hardened material for supporting the weight of carriage  16  and router  18  on ledge  78  when lifted by handle  12 . 
         [0030]    Thus, adjustment assembly  10  provides a mechanism for rapid vertical adjustment of a rotary cutter which is also conveniently combined with a fine adjustment mechanism for accurately and incrementally positioning the carriage assembly and rotary cutter at a desired height. The rapid adjustment mechanism is very simple and effective and conveniently ties directly into the fine adjustment mechanism, thereby producing a very streamlined mechanism involving a minimal number of moving parts. 
         [0031]    It will be evident to one skilled in the art that a variety of changes can be made that are within the scope of the present invention. For instance, the rapid movement assembly may be configured as an independent unit for use without a fine adjustment mechanism or configured for use with a different fine adjustment mechanism. In addition, a lift handle may be configured for engagement with a carriage assembly to provide the convenience of lifting the assembly via the handle which extends above the table plate without the lift handle also serving to disengage the carriage assembly from the adjustment screw or another type of support assembly. 
         [0032]    In the foregoing description, certain terms have been used for brevity, clearness, and understanding. No unnecessary limitations are to be implied therefrom beyond the requirement of the prior art because such terms are used for descriptive purposes and are intended to be broadly construed. 
         [0033]    Moreover, the description and illustration of the invention is an example and the invention is not limited to the exact details shown or described.