Abstract:
A router plane having a collar maintained in snug engagement with a blade shank during blade height adjustment to facilitate accurate adjustment with a threaded adjustment nut that travels on an adjustment post. The collar is retained on a post secured to the router plane body so that the collar can rotate between blade in-board and blade out-board positions without removal from the post.

Description:
FIELD OF THE INVENTION 
       [0001]    This invention relates to manual or hand router planes. 
       BACKGROUND OF THE INVENTION 
       [0002]    Router planes or routers are fitted with a relatively narrow cutter and are generally used to form or refine a recess in a work piece. Typically a body having a sole for contact with a work piece is held and manipulated by two handles or knobs attached to the body, and a cutter having a cutting arris on a foot projecting from a the cutter shank is secured to the body to project below the sole. 
         [0003]    The blade or cutter in router planes has usually been a sharpened foot projecting at approximately a right angle from a shank or shaft that is secured in the plane body in a position orthogonal to the router sole. Such a blade is usually secured to an upstanding post portion of the plane body also orthogonal to the router sole, typically with a collar that encircles the blade shaft or shank and upstanding post, and a thumbscrew threaded into the collar bears against the post to tighten the collar. Early router planes held the blade or cutter in place solely by friction, and positioning was accomplished by loosening the collar and sliding the blade to a new position. Later improvements used a thumbnut traveling on a threaded rod fixed in the plane body to adjust the position of the cutter. 
         [0004]    Notwithstanding such improvements, the depth of cut and position of blades have often been difficult to adjust accurately and repeatably in prior router planes. Alternatives for lateral positioning of the blade or cutter have also been limited. 
         [0005]    Consequently, there remains a need for an improved router plane. 
       SUMMARY OF THE INVENTION 
       [0006]    The router plane of this invention preferably utilizes a generally square cross-section blade shaft or shank that is mountable in either of two alternative locations in the body and in multiple rotational positions in the outboard or bullnose location. The blade shaft is secured to the body with an appropriately shaped collar that accommodates the multiple rotational positions and can be rotated relative to the body to permit the shaft to be secured in either of the two alternative positions. The spring-loaded blade-clamping collar holds the blade in position when the collar is loosened and provides tactile feedback for controlled blade depth adjustment. The collar can also be made to fully release by pressing the collar-tightening thumb screw forward after rotating it to loosen it for quick and easy blade removal or reorientation. The blade can be positioned in front of the post (inboard of the plane body) for general work, behind the post (outboard of the body) for bullnose applications or laterally (left or right) for work on hinge gains. 
         [0007]    The collar is located on a body post that has a projecting rim. This rim and the pin structure associated with the collar together limit upward travel of the collar so that the collar cannot be removed without removing the body post from the body. The blade is secured to the body with the collar utilizing a locking knob having a shaft threaded into the collar and to which a spring loaded, telescoping locking pin is attached in such a manner that the locking collar will be held snugly in position even when the locking knob is not fully tightened. This reduces backlash during blade adjustment, facilitating precise blade positioning and adjustment. Protrusions located on the inside surface of the collar contact the blade shaft in a manner that insures that the blade accurately aligns itself with one of two V-grooves in the body post rather than by reference to the collar itself. 
     
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0008]      FIG. 1  is a perspective view of the front and right side of the router plane of this invention. 
           [0009]      FIG. 2  is an exploded perspective view of the router plane shown in  FIG. 1 , together with alternative blades and a blade holder for blade sharpening. 
           [0010]      FIG. 3  is a right side view, in section, taken through the middle of the router plane of  FIG. 1 . 
           [0011]      FIG. 4  is a partial top view of the router plane of  FIG. 1 , with the Iuiobs omitted and in horizontal section through the middle of the locking collar, post and blade shaft. 
           [0012]      FIG. 5  is a side elevation view of the router plane of  FIG. 1  with a portion of the plane body broken away to improve visibility of the blade depth adjusting and locking mechanisms. 
           [0013]      FIG. 6  is a perspective view similar to  FIG. 1  but with the blade removed. 
           [0014]      FIG. 7  is a perspective view of the left side and front of the router plane of  FIG. 1  with the locking collar and blade rotated to the outboard blade position. 
           [0015]      FIG. 8  is an enlarged perspective view of the top and inboard side of the body post of the plane shown in  FIG. 1 . 
       
    
    
     DETAILED DESCRIPTION 
       [0016]    In the figures, a router plane  10  exemplary of this invention has a plane body  12  manipulated with knobs  14  to cause a blade  16  to engage a work piece (not shown) as desired. Blade  16  has a foot  18  attached to a shank or shaft  20 . Shaft  20  is secured to plane body  12  with a collar  22  that encircles the shaft  20  and clamps it against a body post  24  by rotating a thumb screw  26 . The projection of blade  16  beyond the sole  28  of body  12  can be adjusted in small increments by rotating blade adjustment knob or thumb nut assembly  30  which is threaded onto a threaded adjustment post  32 . 
         [0017]    Blade adjustment assembly  30  may be fabricated in one piece or it may be, as illustrated in  FIG. 2 , two pieces: a knurled knob  34  (which can be brass) and an internally threaded disk  36  (that can be steel) that has a washer-shaped flange  38  that engages a neck  40  near the top of shaft  20  to drive shaft  20 ,  20 ′, or  20 ″ up or down by rotating knurled knob  34 . 
         [0018]    As can be appreciated by reference to  FIGS. 2 and 3 , collar  22  encircles body post  24  and is trapped on that post when post  24  is secured to the body  12  because its lip or rim  42  prevents collar  22  from moving upward on post  24 . Body post  24  is secured to the body  12  with a threaded post  32  that passes through post  24  and, with a smaller diameter threaded portion  44 , is screwed into body  12 . 
         [0019]    As may be appreciated by reference to  FIG. 2 , the narrow blade  16  shown in  FIG. 1  can, when desired, be replaced by a wider blade  16 ′ having a wider foot  18 ′ on a corresponding shaft  20 ′ or a spear point blade  16 ″ having a spear point cutter  18 ″ on a shaft  20 ″. 
         [0020]    Collar  22  is tightened against shank  20 ,  20 ′,  20 ″ by rotating thumb screw or locking knob  26  to press locking pin  48  against body post  24 , thereby drawing shank  20 ,  20 ′,  20 ″ tightly against body post  24 . As may be appreciated by reference to  FIGS. 3 and 4 , locking pin  48  telescopes into the shank  46  of thumb screw  26  and is spring loaded by spring  49  so that pin  48  continues to exert some force on body post  24  even when thumb screw  26  has been loosened by a small amount. This keeps collar  22  relatively snugly in contact with shank  20 ,  20 ′,  20 ″ during adjustment of the position of blade  16 , greatly facilitating easy adjustment by preventing blade  16  from falling out of position as soon as thumb screw  26  is loosened. Pin  48  is retained in thumb screw  26  by a machine screw  50  inserted through the head  52  of thumb screw  26  and into the head  54  of pin  48 . When knob  26  is rotated to tighten collar  22 , pin  48  slides into shank  46  until the head  54  of pin  48  contacts the end  56  of shank  46 , thereby firmly fixing collar  22  and blade  16  in position on body post  24 . (As is best seen in  FIG. 4 , pin  48  always contacts body post  24  at a flat surface—either surface  74  when the blade  16  is positioned inboard as it is in  FIGS. 1 ,  2 ,  3  and  5 , or surface  75  when blade  16  is positioned outboard as illustrated in  FIG. 7 . This flat surface to flat surface contact facilitates secure locking of collar  22  and effective function of the spring-loaded pin  48  feature.) With collar  22  slightly loosened, the height of blade  16  may be adjusted by rotating thumb nut assembly  30 . Downward travel of thumb nut assembly  30  (and therefore depth of cut of blade  16 ) may be limited at a predetermined position by locking stop nuts  58  in a position on threaded post  32  that stops travel of thumb nut  30  with blade  16  at a desired position. Stop nuts  58  can be locked in a position by tightening them against each other. Alternatively, a set screw (not shown) threaded into one of the stop nuts  58  can be used to lock that stop nut to the post  32 . 
         [0021]    The blade  16  may be formed in one piece having a shank  20  and a foot  18  or with separate shank  20 ′ or  20 ″ and a removable foot  18 ′ or  18 ″ secured to the shank with a screw  60 . A series of grooves  62  in foot  18 ′ or  18 ″ inter-fits with a corresponding series of grooves  64  on shank  20 ′ or  20 ″ (illustrated in  FIG. 3 ) to facilitate correct positioning and retention of the foot on the shank when the two are attached with a screw  60 . 
         [0022]    Detachable feet  18 ′ or  18 ″ can be more easily sharpened by attaching them to a sharpening blade holder  66  with a screw  68  (both illustrated in  FIG. 2 ). 
         [0023]    Although shanks  20 ,  20 ′ and  20 ″ could be round or have other cross-sectional shapes, if they are generally square they can seat very firmly and be effectively retained by protrusions  23  on the inside of collar  22  without rotating in one of the two V-shaped grooves  70  and  72  in body post  24  as can be seen in  FIG. 4 . Compare, for instance  FIGS. 1 and 7  to see positioning in the two V-shaped grooves  70  ( FIG. 1) and 72  ( FIG. 7 ). Moreover, the generally square cross sectional shape enables shanks  20 ,  20 ′ and  20 ″ to be positioned in the bullnose or outboard position shown in  FIG. 7  in alternative rotational positions rotated by 90 degrees from each other. As is illustrated in  FIGS. 1 ,  2 ,  3  and  8 , the V-shaped groove  70  in body post  24  is aligned with a V-shaped groove  76  in body  12 . This lower V-shaped groove  76  provides support for shank  20 ,  20 ′,  20 ″ low on the shank and near foot  18 ,  18 ′,  18 ″ when the blade  16  is positioned inboard as illustrated in  FIGS. 1 ,  2 ,  3  and  5  to reduce shank flexing and blade chatter. It is not possible to provide identical support against body  12  when blade  16  is positioned outboard as illustrated in  FIG. 7  because such support would prevent rotating blade  16  to a left or right lateral position when it is outboard. However, body post  24  carries a lower V-shaped groove  77  on the outboard side of post  24  to provide additional shank support in the outboard position. 
         [0024]    As will be appreciated by those skilled in the art numerous modifications and variations of the router plane  10  described above and illustrated in the figures can be made without departing from the scope and spirit of this invention or the following claims. For instance, a variety of materials could be used for the plane components, including, but not limited to, ductile iron for the plane body  12 , ductile iron or stainless steel for body post  24 , wood, metal or plastic for the knobs  14 , steel or brass for the threaded components and a variety of other appropriate materials. Additionally, alternative structures could be used in order to exert sufficient pressure to hold the collar  22  and blade  16  in position during the adjustment process even when the collar locking mechanism is disengaged. For instance, other spring and pin arrangements could be used, or a spring arrangement holding the components in position could be made separate from the position locking mechanism provided by thumbscrew  26  in the embodiment described in detail above. These and other such modification are within the scope of the present invention.