Closure cap

Abstract

A closure cap for openings on motor vehicle radiators is provided with a cap inner part that is held on a cap outer part. A valve assembly for opening and blocking a flow connection between the inside of the reservoir and the outside of the reservoir is held inside said cap inner part. The valve assembly comprises a valve body, which can move in a to-and-fro manner, is pressed in a pretensioned manner by spring action against a sealing seat on the cap inner part, and which can be lifted from the sealing seat when a specified limit value of the internal pressure of the reservoir is exceeded. The aim of the invention is to provide a closure cap of the aforementioned type whose sealing seat, which is located between the cap inner part and the valve body facing said cap inner part, undergoes a definable reduction of tension when the venting flow path is opened. To this end, the sealing seat on the cap inner part is formed by an O-ring, which is held inside an axially open annular groove, and this annular groove is radially enlarged by venting pockets provided on a circumferential edge.

1 - 5 . (canceled)  
   
   
       6 . A closure cap for a reservoir opening having: a cap outer part; 
 a cap inner part, retained on said cap outer part, said cap inner part defines a sealing seat and an axially open annular groove; and    a valve assembly situated in said cap inner part, for opening and blocking a flow connection between the inside of the reservoir and the outside of the reservoir, said valve assembly having a valve body movable back and forth and which is resiliently prestressed, and pressed against said sealing seat and which can be lifted from said sealing seat if a defined limit value of the internal reservoir pressure is exceeded, wherein:    said sealing seat is formed by an O-ring retained in said axially open annular groove, and    said annular groove is radially widened by venting pockets provided on a circumferential edge of said annular groove.    
   
   
       7 . The closure cap according to  claim 6 , wherein: 
 said venting pockets radially adjoin the outer circumferential edge of said annular groove.    
   
   
       8 . The closure cap according to  claim 6 , wherein: 
 said venting pockets extend over the entire depth of said annular groove.    
   
   
       9 . The closure cap according to  claim 6 , wherein: 
 said venting pockets are distributed uniformly over the circumference of said annular groove.    
   
   
       10 . The closure cap according to  claim 6 , wherein: 
 said venting pockets are formed by narrow radial slots.    
   
   
       11 . The closure cap according to  claim 7 , wherein: 
 said venting pockets extend over the entire depth of said annular groove.    
   
   
       12 . The closure cap according to  claim 7 , wherein: 
 said venting pockets are distributed uniformly over the circumference of said annular groove.    
   
   
       13 . The closure cap according to  claim 8 , wherein: 
 said venting pockets are distributed uniformly over the circumference of said annular groove.    
   
   
       14 . The closure cap according to  claim 7 , wherein: 
 said venting pockets are formed by narrow radial slots.    
   
   
       15 . The closure cap according to  claim 8 , wherein: 
 said venting pockets are formed by narrow radial slots.    
   
   
       16 . The closure cap according to  claim 9 , wherein: 
 said venting pockets are formed by narrow radial slots.