Noise elimination brake for automatic spindle locking mechanism

Abstract

A rotary power tool of the invention has a motor, a motor shaft driven by the motor, an output shaft coupled to the motor shaft via an automatic spindle locking mechanism, a housing portion surrounding the output shaft, and a braking member that is non-rotatable relative to the housing portion. The braking member exercises a braking torque on the output shaft whenever it rotates.

1 - 11 . (canceled) 
   
   
       12 . A rotary power tool comprising:
 a motor;   a motor shaft driven by the motor;   an output shaft coupled to the motor shaft via an automatic spindle locking mechanism;   a housing portion surrounding the output shaft; and   a braking member that is non-rotatable relative to the housing portion, which the braking member exercises a braking torque on the output shaft whenever the output shaft rotates.   
   
   
       13 . A rotary power tool according to  claim 12 , wherein the output shaft is stabilized by at least two bearing members and the braking member is positioned between the at least two bearing members. 
   
   
       14 . A rotary power tool according to  claim 12 , wherein the braking member is ring-shaped and contacts the output shaft along its inner surface. 
   
   
       15 . A rotary power tool according to  claim 13 , wherein the braking member is ring-shaped and contacts the output shaft along its inner surface. 
   
   
       16 . A rotary power tool according to  claim 12 , wherein the braking member is in direct contact with the housing portion. 
   
   
       17 . A rotary power tool according to  claim 15 , wherein the braking member is in direct contact with the housing portion. 
   
   
       18 . A rotary power tool according to  claim 12 , wherein the braking member and the housing portion are coupled by an interference fit. 
   
   
       19 . A rotary power tool according to  claim 17 , wherein the braking member and the housing portion are coupled by an interference fit. 
   
   
       20 . A rotary power tool according to  claim 12 , wherein an inner surface of the braking member has a chamfer-shaped surface. 
   
   
       21 . A rotary power tool according to  claim 20 , wherein an inner surface of the braking member has a chamfer-shaped surface. 
   
   
       22 . A rotary power tool according to  claim 12 , wherein an outer surface of the braking member has a structure complimentary with an inner surface of the housing portion. 
   
   
       23 . A rotary power tool according to  claim 21 , wherein an outer surface of the braking member has a structure complimentary with an inner surface of the housing portion. 
   
   
       24 . A rotary power tool according to  claim 12 , wherein the braking torque is of sufficient magnitude so that in an absence of an external torque urging the output shaft to rotate, a rotating velocity of the output shaft is always less than or equal to a rotating velocity of the motor shaft. 
   
   
       25 . A rotary power tool according to  claim 23 , wherein the braking torque is of sufficient magnitude so that in an absence of an external torque urging the output shaft to rotate, a rotating velocity of the output shaft is always less than or equal to a rotating velocity of the motor shaft. 
   
   
       26 . A rotary power tool according to  claim 12 , wherein the braking member is made of a flexible non-metal material. 
   
   
       27 . A rotary power tool according to  claim 25 , wherein the braking member is made of a flexible non-metal material. 
   
   
       28 . A rotary power tool according to  claim 12 , wherein the braking member is composed of felt. 
   
   
       29 . A rotary power tool according to  claim 27 , wherein the braking member is composed of felt. 
   
   
       30 . A rotary power tool according to  claim 12 , wherein the braking member is composed of plastic, rubber or foam. 
   
   
       31 . A rotary power tool according to  claim 27 , wherein the braking member is composed of plastic, rubber or foam.