Water Pump For Marine Engine Having Removable Cap Assembly

Abstract

A water pump for a marine engine includes a drive flange for rotating a drive shaft, a housing having an internal cavity and a removable cap assembly. The removable cap assembly includes a cap lock ring secured to the housing, a cartridge extending into the internal cavity of the housing and an impeller rotatable inside the cartridge. The cap lock ring and cartridge are snap-fit together. The rotatable drive shaft has splines, which mate with a splined portion of an impeller to rotate the impeller. To replace the impeller, an operator twists the cap lock ring off the housing without any tools and pulls the cap assembly away from the housing disengaging the impeller from the drive shaft. A new cap assembly replaces the worn cap assembly.

What is claimed is: 
     
         1 . A water pump for a marine engine, the water pump comprising:
 a housing having an internal cavity having an open end and external threads;   a drive assembly comprising a drive flange adapted to be rotated by the marine engine and a drive shaft having splines, the drive shaft extending inside the internal cavity of the housing;   a cap assembly comprising a cap lock ring, a cartridge secured to the cap lock ring and an impeller inside the cartridge, the cap lock ring having internal threads along a continuous sidewall, the internal threads of the cap lock ring engaging the external threads of the housing to secure the cap lock ring to the housing; and   the cartridge of the cap assembly being secured to the cap lock ring of the cap assembly and being sized to fit inside the internal cavity of the housing,   the impeller of the cap assembly having a plurality of flexible blades extending radially outwardly from a central portion, a bore extending through the central portion of the impeller, the bore having a splined portion, the splined portion of the impeller bore mating with the splines of the drive shaft such that rotation of the drive shaft rotates the impeller inside the cartridge, and   wherein the cap assembly is capable of being disengaged from the housing and replaced to provide a new impeller, new cartridge and new cap lock ring.   
     
     
         2 . The water pump of  claim 1 , further comprising a hose bib cap secured to the housing, the hose bib cap comprising first and second nipples, the first nipple being adapted to couple to an inlet hose and the second nipple being adapted to couple to an outlet hose. 
     
     
         3 . The water pump of  claim 1 , wherein the housing has a mounting portion for mounting the housing to a marine engine. 
     
     
         4 . The water pump of  claim 1 , wherein the cap lock ring is rotatable relative to the cartridge of the cap assembly. 
     
     
         5 . The water pump of  claim 1 , wherein the cap lock ring and the cartridge of the cap assembly are snap-fit together. 
     
     
         6 . The water pump of  claim 1 , further comprising bearings inside the housing to facilitate rotation of the drive shaft. 
     
     
         7 . The water pump of  claim 1 , wherein the cap lock ring has integral tabs to facilitate rotating the cap lock ring. 
     
     
         8 . A water pump for a marine engine, the water pump comprising:
 a housing having an internal cavity and external threads on an open end of the internal cavity;   a rotatable drive shaft having splines, the drive shaft extending inside the internal cavity of the housing;   a cap assembly comprising a cap lock ring having internal threads, the internal threads of the cap lock ring being adapted to engage the external threads on the open end of the internal cavity of the housing;   the cap assembly further comprising a cartridge secured to the cap lock ring, the cartridge being sized to fit inside the internal cavity of the housing and cover the open end of the internal cavity of the housing,   the cap assembly further comprising an impeller, the impeller having a plurality of flexible blades extending radially outwardly from a central portion, a bore extending through the central portion of the impeller, the bore having a splined portion which engages the splines of the drive shaft such that rotation of the drive shaft rotates the impeller inside the cartridge of the cap assembly;   wherein the cap assembly is removable and replaceable without use of any tools.   
     
     
         9 . The water pump of  claim 8 , wherein the cartridge has first and second openings aligned with first and second openings extending through the housing. 
     
     
         10 . The water pump of  claim 9 , further comprising a hose bib cap removably attached to the housing, the hose bib cap comprising first and second nipples surrounding the first and second openings in the housing, the first nipple being sized to couple to an inlet hose and the second nipple being sized to couple to an outlet hose. 
     
     
         11 . The water pump of  claim 8 , wherein the housing has a mounting portion for mounting the housing to a marine engine. 
     
     
         12 . The water pump of  claim 8 , wherein the cap lock ring and cartridge are snap-fit together. 
     
     
         13 . The water pump of  claim 8 , further comprising bearings inside the housing to facilitate rotation of the drive shaft. 
     
     
         14 . The water pump of  claim 8 , wherein the cap lock ring is a unitary member having tabs to facilitate rotating the cap lock ring. 
     
     
         15 . A water pump for a marine engine, the water pump comprising:
 a housing having an internal cavity having an open end, the housing having external threads around the open end of the internal cavity;   a drive shaft;   a cap assembly comprising a cap lock ring having internal threads adapted to engage the external threads around the open end of the internal cavity of the housing; and   the cap assembly further comprising a cartridge secured to the cap lock ring, the cartridge having a hollow interior and being sized to fit inside the internal cavity of the housing and cover the open end of the internal cavity of the housing, the cartridge having an open bottom, such that the drive shaft extends though the housing and into the hollow interior of the cartridge;   the cap assembly further comprising a rotatable impeller inside the hollow interior of the cartridge, the impeller having a plurality of flexible blades extending radially outwardly from a central portion, a bore extending through the central portion of the impeller, the bore being adapted to engage the drive shaft such that rotation of the drive shaft rotates the impeller inside the hollow interior of the cartridge;   wherein the cap assembly is removable from the housing without tools to replace the impeller.   
     
     
         16 . The water pump of  claim 15 , wherein the housing comprises two mounting bosses for mounting the housing to a marine engine. 
     
     
         17 . The water pump of  claim 15 , the cartridge has first and second openings aligned with first and second openings extending through the housing. 
     
     
         18 . The water pump of  claim 17 , further comprising a hose bib cap secured to the housing, the hose bib cap comprising first and second nipples surrounding the first and second openings in the housing, the first nipple being sized to couple to an inlet hose and the second nipple being sized to couple to an outlet hose. 
     
     
         19 . The water pump of  claim 15 , wherein the cartridge and cap lock rings are plastic and snapped fit together. 
     
     
         20 . The water pump of  claim 15 , further comprising bearings inside the housing to facilitate rotation of the drive shaft.