Switchable Valve Lifter Having a Mis-Assembly Indicator

Abstract

An improved SHVL for an internal combustion engine comprises an improved arrangement for locking a spring tower into a pin housing. The spring tower is provided with an annular OD groove as in the prior art. The pin housing ID groove is modified to have a two-step groove comprising two adjacent regions having different depths (different diameters) and having a distinct transition lip therebetween. A spring clip of the correct size seats properly in the spring tower groove and in the lesser-diameter pin housing groove, resulting in a correct overall length of the SHVL. Any oversize clip is caught between the lower lip of the spring tower groove and the transition lip of the two-step pin housing groove, resulting in a SHVL distinctly shorter than nominal, which is easily detected by either direct length measurement or a gauge.

1 . A switchable hydraulic valve lifter for an internal combustion engine, comprising:
 a) a spring tower having an annular groove formed in an outer surface thereof;   b) a pin housing having a bore for receiving said spring tower and having a two-step annular groove formed in an inner surface thereof; and   c) an expansion clip disposed in said spring tower annular groove and said pin housing two-step annular groove for locking said spring tower into said pin housing bore,   wherein said two-step annular groove is defined by a first groove having a first diameter, a second groove adjacent said first groove and having a second and larger diameter,   wherein a correctly-sized expansion clip is accepted into said spring tower annular groove and into said pin housing first groove, resulting in said switchable hydraulic valve lifter having a first overall length, and   wherein an oversized expansion clip is prevented from entering said pin housing first groove, resulting in said switchable hydraulic valve lifter having a second overall length.   
     
     
         2 . A switchable hydraulic valve lifter, in accordance with  claim 1 , wherein said two-step annular groove includes a transition lip formed between said first and second grooves. 
     
     
         3 . A switchable hydraulic valve lifter, in accordance with  claim 1 , wherein said first overall length is greater than said second overall length. 
     
     
         4 . An internal combustion engine, comprising a switchable hydraulic valve lifter including
 a spring tower having an annular groove formed in an outer surface thereof,   a pin housing having a bore for receiving said spring tower and having a two-step annular groove formed in an inner surface thereof, and   an expansion clip disposed in said spring tower annular groove and said pin housing two-step annular groove for locking said spring tower into said pin housing bore,   wherein said two-step annular groove is defined by a first groove having a first diameter, a second groove adjacent said first groove and having a second and larger diameter,   wherein a correctly-sized expansion clip is accepted into said spring tower annular groove and into said pin housing first groove, resulting in said switchable hydraulic valve lifter having a first overall length, and   wherein an oversized expansion clip is prevented from entering said pin housing first groove, resulting in said switchable hydraulic valve lifter having a second overall length.   
     
     
         5 . A method for sorting mis-assembled switchable hydraulic valve lifters from a population of switchable deactivating hydraulic valve lifters, comprising the steps of:
 a) establishing a predetermined correct overall length for a correctly-assembled switchable hydraulic valve lifter;   b) measuring the overall length of each of said switchable hydraulic valve lifters; and   c) segregating any switchable hydraulic valve lifters having an overall length other than said predetermined correct overall length.