Vibration dampening of a power tool

Abstract

The invention provides a power tool assembly having a motor. The power tool assembly includes a housing having an inner surface defining a cavity enclosing the motor. The power tool assembly also includes a layer of polyurethane elastomer disposed on the inner surface and extending into the cavity. The polyurethane elastomer dampens vibration of the motor during operation of the power tool assembly.

1 . A power tool assembly comprising: 
 a housing having an inner surface defining a cavity;    a motor disposed within said cavity of said housing and coupled to said inner surface; and    a layer of polyurethane elastomer disposed at least partially on said inner surface for dampening vibration of said motor during operation of the power tool assembly.    
   
   
       2 . A power tool assembly as set forth in  claim 1  wherein said layer of polyurethane elastomer is further defined as a layer of microcellular polyurethane.  
   
   
       3 . A power tool assembly as set forth in  claim 1  wherein said layer of polyurethane elastomer includes a first surface attached to said inner surface and a second surface opposite the first surface projecting into said cavity.  
   
   
       4 . A power tool assembly as set forth in  claim 3  wherein said second surface of said elastomer is further defined as being spaced from said inner surface and said motor.  
   
   
       5 . A power tool assembly as set forth in  claim 1  wherein said layer of polyurethane elastomer covers substantially all of said inner surface of said housing.  
   
   
       6 . A power tool assembly as set forth in  claim 6  wherein said housing further including: 
 a first housing shell defining a first portion of said inner surface; and    a second housing shell defining a second portion of said inner surface with said second housing shell being connectable to said first housing shell to define said cavity and said layer of polyurethane elastomer disposed on both of said first and said portions.    
   
   
       7 . A power tool assembly as set forth in claim I wherein said housing further including: 
 a first housing shell defining a first portion of said inner surface and having a plurality of first bosses projecting from said first portion of said inner surface;    a second housing shell defining a second portion of said inner surface and having a plurality of second bosses projecting from said second portion of said inner surface with said second housing shell being connectable to said first housing shell to define said cavity and said layer of polyurethane elastomer encircling at least one of said first and said second bosses.    
   
   
       8 . A power tool assembly as set forth in  claim 7  wherein said layer of polyurethane elastomer encircles all of said first and second bosses.  
   
   
       9 . A power tool assembly as set forth in  claim 1  wherein said layer of polyurethane elastomer is discontinuous.  
   
   
       10 . A power tool assembly as set forth in  claim 9  wherein said layer of polyurethane elastomer is further defined as a plurality of discrete pieces spaced from one another about said inner surface.  
   
   
       11 . A power tool assembly as set forth in  claim 1  further including a tool member coupled to said motor and driven in motion by said motor with said tool member selected from a group consisting of a drill bit chuck, a saw blade and a fan.  
   
   
       12 . A method of assembling a power tool assembly having a housing with an inner surface, a motor, and a layer of polyurethane elastomer, said method comprising the steps of: 
 disposing the layer of polyurethane elastomer on the inner surface; and    enclosing the motor within the inner surface of the housing wherein the layer of polyurethane elastomer dampens vibration generated by the motor during operation of the power tool assembly.    
   
   
       13 . A method as set forth in  claim 12  wherein the layer of polyurethane elastomer includes a first surface and a second surface opposite the first surface and wherein the step of disposing the layer of polyurethane elastomer is further defined as: 
 attaching the first surface of the elastomer to the inner surface of the housing; and    exposing the second surface of the elastomer to an interior cavity of the housing.    
   
   
       14 . A method as set forth in  claim 12  wherein the step of disposing the layer of polyurethane elastomer is further defined as substantially covering all of the inner surface of the housing with the layer of polyurethane elastomer.  
   
   
       15 . A method as set forth in  claim 12  wherein the step of disposing the layer of polyurethane elastomer is further defined as wedging the layer of polyurethane elastomer between the motor and the inner surface of the housing.  
   
   
       16 . A method as set forth in  claim 12  the step of disposing the layer of polyurethane elastomer is further defined as adhering the layer of polyurethane elastomer to the inner surface with an adhesive.  
   
   
       17 . A method as set forth in  claim 12  wherein the step of disposing the layer of polyurethane elastomer is further defined as overmolding the layer of polyurethane elastomer on the inner surface.