Safety Pressure Cap

Abstract

A safety radiator cap has a centrally located pressure plunger that forces pins outward against the inside of a radiator fill tube to prevent opening of the cap when the system is under pressure. As the liquid cools, the pressure is reduced and the pins retract due to biasing springs which allow the cap to be removed thus ensuring that the cap can only be removed when safe. Pressure pads at the end of the pins allow an embodiment of the invention to be used in any vehicle without retrofitting.

1 . A safety pressure cap comprises:
 a housing;   a cap portion disposed on an upper end of said housing;   a lower sealing portion disposed towards a lower end of said housing;   a center slide centrally disposed in said housing;   a pressure plunger having a sloping section;   said pressure plunger being slidably constrained to move along said center slide; and   at least one pin having a following end moveably disposed to move along said sloping section wherein said at least one pin moves generally perpendicular to a longitudinal axis defined by said center slide.   
   
   
       2 . The safety pressure cap according to  claim 1  further comprising a pressure spring disposed between said cap portion and said lower sealing portion. 
   
   
       3 . The safety pressure cap according to  claim 1  further comprising a sealing gasket disposed on a lower side of said cap portion. 
   
   
       4 . The safety pressure cap according to  claim 3  further comprising a plunger biasing spring centrally disposed between said housing and an upper portion of said pressure plunger. 
   
   
       5 . The safety pressure cap according to  claim 4  further comprising at least one pin biasing spring disposed between said following end and a side of said housing whereby said pin is biased against said sloping section. 
   
   
       6 . The safety pressure cap according to  claim 5  further comprising a locking end disposed on an outside end of said pin. 
   
   
       7 . The safety pressure cap according to  claim 6  wherein said locking end is made of rubber. 
   
   
       8 . The safety pressure cap according to  claim 1  further comprising:
 a collar whereby said safety pressure cap removeably fits substantially within;   at least one locking means disposed in said collar substantially aligned with said at least on pin wherein when said pin is outwardly moved, said safety pressure cap is locked in place until said pin retracts.   
   
   
       9 . The safety pressure cap according to  claim 8  wherein said at least one locking means is an opening in said collar. 
   
   
       10 . The safety pressure cap according to  claim 8  wherein said at least one locking means is a ridge disposed on an inner surface of said collar. 
   
   
       11 . A safety pressure cap comprises:
 a housing;   a cap portion disposed on an upper end of said housing;   a lower sealing portion movably disposed towards a lower end of said housing wherein said lower sealing portion moves in response to pressure;   a pin slide having a sloping section fixedly disposed within said housing; and   at least one pin having a following end moveably disposed to move along said sloping section wherein said at least one pin moves generally perpendicular to a longitudinal axis of said safety pressure cap.   
   
   
       12 . A safety pressure cap comprises:
 a housing;   an upper sealing means for sealing said safety pressure cap;   a lower sealing means for sealing said safety pressure cap against an inner collar; and   a pressure retaining means for locking said safety pressure cap when under pressure.   
   
   
       13 . The safety pressure cap according to  claim 12  wherein said upper sealing means is a gasket disposed on a lower surface of said safety pressure cap. 
   
   
       14 . The safety pressure cap according to  claim 13  wherein said lower sealing means is a moveably disposed plug having a sealing gasket disposed on a bottom surface therein. 
   
   
       15 . The safety pressure cap according to  claim 12  wherein said pressure retaining means comprises a pin slide centrally disposed therein and at least one pin having a pin follower on an end therein whereby said pin moves in response to pressure by moving along a sloping surface of said pin slide. 
   
   
       16 . The safety pressure cap according to  claim 15  further comprising a locking end disposed on an opposite end of said at least one pin. 
   
   
       17 . The safety pressure cap according to  claim 8  wherein said collar is disposed on a radiator. 
   
   
       18 . The safety pressure cap according to  claim 8  wherein said collar is disposed on a radiator overflow. 
   
   
       19 . The safety pressure cap according to  claim 1  further comprises a hold down portion disposed on said cap portion. 
   
   
       20 . The safety pressure cap according to  claim 19  wherein said hold down portion is a screw tab.