Abstract:
A trim router heat sink with a bearing seat and shaft lock that mount to a trim router to act as a heat sink. A shaft extends through the bearing seat and has a shaft lock. The shaft is held on one end by the trim router&#39;s motor shaft and on the other end by a bearing. The shaft is connected to a collet so that when the motor of the trim router is operated, the shaft turns the collet. The shaft can be locked to facilitate the installation or removal of a cutting tool in the collet.

Description:
BACKGROUND  
       [0001]     The present invention relates to a router heat sink system. More particularly, the present invention relates to a router heat sink that includes an integral bearing seat and shaft lock.  
         [0002]     The motor shaft bearing of a router generates considerable heat during operation of the router. It is desirable to dissipate this heat to avoid overheating and possibly damaging the motor shaft bearing and motor which could result in shortening the lifespan of both the motor shaft bearing and motor. Traditional routers that may be powered by being connected to 120 volt alternating current power source, such as that found in the typical household or construction site, incorporate a fan to circulate air through the housing of the router. This is acceptable for traditional routers connected to 120 volt alternating current power source since there is no need to conserve power. However, battery operated routers have a finite amount of power available in any given battery pack. In a battery operated router, in order to maximize the amount of work that can be performed by a battery pack, it is desirable to conserve the battery power as much as possible and to have as much of the battery power as possible available for driving the router&#39;s motor. Therefore, it is not desirable to use a fan to cool the motor shaft bearing of the router since the fan increases the drain of power from the battery pack, thereby decreasing the amount of useful work that can be performed between charges.  
         [0003]     Additionally, all routers, whether traditionally powered by 120 volt alternating current or by a direct current battery pack, have the inherent need of keeping the motor, motor shaft and collet aligned. This alignment need is even more pronounced in routers that have a plastic housing since the plastic housing may not be strong enough to provide a fixed support for the motor shaft and collet.  
         [0004]     Finally, it is desirable to have a router with a shaft lock to facilitate the tightening and loosening of the collet when changing bits. In routers with a plastic housing, many difficulties are encountered in attempting to mount a shaft lock through the plastic body because the torque applied to the housing when the lock is engaged can deform the plastic housing.  
       BRIEF SUMMARY  
       [0005]     In accordance with the present invention, a router heat sink is provided. The router heat sink includes an integral bearing seat and shaft lock. The heat sink piece can be made of any type of heat conducting material known to those of skill in the art. In one embodiment, the heat sink is made of a die cast metal. In another embodiment, the heat sink is made of two pieces of die cast metal where the first heat sink piece can be fastened to the motor in contact with the motor shaft bearing and the second heat sink piece can be attached to the first. The first heat sink piece acts as a heat sink for the motor shaft bearing. The second heat sink piece is attached on its first end to the first heat sink piece and on its second end provides a bearing seat for housing an output shaft bearing. The second heat sink piece acts as a heat sink to the output shaft bearing and the motor shaft bearing. The output shaft bearing seat is dimensioned so that the output shaft bearing fits securely therein. Additionally, the second heat sink piece provides a hollow portion for a shaft lock to engage.  
         [0006]     A output shaft extends through the two die cast pieces and the output shaft bearing. The output shaft connects to the motor at one end and to a collet and collet nut on the opposite end. The alignment of the output shaft with the motor and the collet is maintained by the output shaft bearing. Alternatively, the output shaft and the output shaft bearing can be constructed as a single assembly while retaining the same functionality.  
         [0007]     The output shaft includes a hollow portion for engagement with a shaft lock. The shaft lock passes through the router housing and engages the hollow portion of the heat sink and the hollow portion of the output shaft thereby preventing rotation of the shaft. The shaft lock is held in place by a spring clip. 
     
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       [0008]      FIG. 1  is an exploded view of a router heat sink system and a router motor and router housing.  
         [0009]      FIG. 2  is a perspective view of one embodiment of a router heat sink system adjacent to a router motor which is in turn installed in a router housing.  
         [0010]      FIG. 3  is a perspective view one embodiment of a router heat sink system according to the present invention adjacent to a router motor. 
     
    
     DESCRIPTION  
       [0011]     Referring to the figures a router heat sink system  100  is shown. The router heat sink system  100  includes a router motor  110 , a first heat sink piece  120 , a second heat sink piece  130 , a output shaft bearing  140 , a output shaft  150 , a shaft lock  160 , and a collet assembly  170 . The router motor  110  includes a base end  112  and an output end  114 . The motor output end  114  includes a motor shaft bearing  116  and an motor shaft  118  for transferring the power of the motor  110  to the output shaft  150  which in turn is connected to the collet assembly  170  which holds a router bit, not shown. The router motor  110  can be any of a variety of battery operated motors capable of powering a router as is known to one skilled in the art.  
         [0012]     The first heat sink piece  120  surrounds the motor shaft bearing  116  near the motor shaft  118  of the motor  110  and provides a heat sink for the motor shaft bearing  116 . The first heat sink piece  120  has a first end  122  and a second end  124 . The first end  122  is adjacent to the output end of the motor  114 . The first heat sink piece  120  is secured to the motor  110  by any of a variety of fasteners. In one embodiment, the first heat sink piece  120  is secured to the motor  110  by a threaded fastener such as a screw or a bolt.  
         [0013]     The second heat sink piece  130  is adjacent to the first heat sink piece  120  and provides a heat sink for the output shaft bearing  140  and an additional heat sink for the motor shaft bearing  116 . The second heat sink piece has a first end  132  and a second end  134 . The first end  132  is adjacent to the first heat sink piece second end  124 . In another embodiment, the second heat sink piece  130  may be connected to the router motor  110 . The second heat sink piece  130  is connected to the first heat sink piece  120  or the router motor  110  by any of a variety of fasteners. In one embodiment, the second heat sink piece  130  is secured to the first heat sink piece  120  by a threaded fastener such as a screw or a bolt. Additionally, an integral bearing seat  136  is formed on the second heat sink piece second end  134 . The integral bearing seat  136  is dimensioned so that a output shaft bearing  140  can be secured therein. The second heat sink piece  130  has a shaft lock opening  138  that is located between the second heat sink piece first end  132  and the second heat sink piece second end  134 . The shaft lock opening  138  is dimensioned so that when a shaft lock  160  is engaged through the shaft lock opening  138  and into the output shaft  150  the rotation of the output shaft  150 , is prevented.  
         [0014]      FIG. 1  also shows the attachment points  127 ,  129  on the first heat sink piece  120  and the attachment points  137 ,  139  on the second heat sink piece  130 . The attachment points  127 ,  129 ,  137 ,  139  allow the first heat sink piece  120  and second heat sink piece  130  to be secured together.  
         [0015]     The first heat sink piece  120  and second heat sink piece  130  can be made of any type of heat conducting material as is known to one of skill in the art. In one embodiment, the first heat sink piece  120  and second heat sink piece  130  are made of metal and can be a die cast metal. In another embodiment, the first heat sink piece  120  and second heat sink piece  130  can be made as a single piece structure rather than as a two piece structure.  
         [0016]     As stated above, the output shaft bearing  140  fits into the integral bearing seat  136  and helps keep the output shaft  150  aligned with the motor shaft  118  of the motor  110 . The output shaft bearing  140  can be any type of bearing capable of functioning at the speeds and loads that are common to routers as is known to one skilled in the art.  
         [0017]     The output shaft  150  has a first end  152  and a second end  154  and contains a shaft lock opening  156  between the first end  152  and the second end  154 . The first end  152  is operatively connected to the motor shaft  118 . The second end  154  is connected to a collet assembly  170 . The output shaft  150  is held in place near the second end  154  by the output shaft bearing  140 . The shaft lock opening  156  is dimensioned so that when the shaft lock  160  is engaged, a portion of the shaft lock  160  protrudes into the shaft lock opening  156  and prevents the output shaft  150  from turning. The output shaft  150  can be constructed of any type of material capable of functioning at the speeds and loads that are common to routers. In one embodiment, the output shaft  150  is made of a metallic material. In another embodiment, the output shaft  150  and the output shaft bearing  140  can be made as a single piece assembly rather than as a two piece assembly.  
         [0018]     The shaft lock  160  is dimensioned so that when it is disengaged the output shaft  150  can freely rotate. However, when the shaft lock  160  is engaged, the shaft lock  160  is aligned with the shaft lock openings  138  and  156  and protrudes into the shaft lock opening  156  to prevent the output shaft  150  from rotating. The shaft lock  160  can be constructed of any type of material capable of withstanding the torque imparted to it when it is engaged and the collet is loosened or tightened such as when the router bits are changed. Additionally, visible in  FIG. 1  is the shaft lock retention device  162 . The shaft lock retention device  162  attaches to the shaft lock  160  and prevents the shaft lock  160  from being unintentionally removed from the router housing  180 .  
         [0019]      FIG. 1  shows the collet  172  and the collet nut  174  which are both part of the collet assembly  170 . When the shaft lock  160  is engaged the collet nut  174  can be tightened or loosened from the output shaft  150 . When the collet nut  174  is tightened to the output shaft  150 , the collet  172  is compressed and a router bit, not shown, can be held in place and rotated by the motor  110  through the motor&#39;s motor shaft  118  and the output shaft  150 .  
         [0020]     Turning now to  FIG. 2 , a perspective view of a router heat sink system  100  is shown. The router heat sink system  100  includes a router motor  110 , a first heat sink piece  120 , a second heat sink piece  130 , a output shaft bearing  140 , a output shaft  150 , a shaft lock  160  a collet assembly  170  and a router housing  180 .  
         [0021]      FIG. 3  shows a perspective view of a router heat sink system  100 . The router heat sink system  100  includes a router motor  110 , a first heat sink piece  120 , a second heat sink piece  130 , a output shaft bearing  140 , a output shaft  150 , a shaft lock  160 , and a collet assembly  170 .  
         [0022]     It is therefore intended that the foregoing detailed description be regarded as illustrative rather than limiting, and that it be understood that it is the following claims, including all equivalents, that are intended to define the spirit and scope of this invention.