Inverted bucket tappet with seal

In a self-compensating hydraulic lash adjuster having a cylindrical hydraulic compression chamber;

• a unidirectional fluid check valve positioned at one end of said compression chamber so as to control the passage of fluid thereto;
• a cylindrical fluid reservoir in communication with said compression chamber through said check valve;
• and a passage between the adjuster exterior and said fluid reservoir through which engine oil may flow as required, the improvement comprising a second check vlave which functions to admit hydraulic engine fluid to said fluid reservoir, to block the reverse flow through said passage from said fluid reservoir and to seal against the leakage of fluid from said fluid reservoir, said second check valve including a flexible annular ring having a diameter approximately equal to, or slightly larger than, the diameter of said fluid reservoir at its point of connection to said passage and further characterized in that said flexible ring is biased against a wall of said fluid reservoir at said point of passage connection so as to be in blocking engagement with said passage opening and further characterized in that positive engine oil pressure acting upon said flexible ring through said passage causes said flexible ring to deform thereby admitting engine oil into said fluid reservoir and that a positive fluid pressure within said fluid reservoir forces said flexible ring into tighter blocking engagement with said fluid reservoir wall thereby further blocking the flow of hydraulic fluid from said fluid reservoir, said flexible ring having a portion positioned against said reservoir wall surrounding said passage, and a support portion extending generally inwardly from said wall portion, and being supported by a portion of said fluid reservoir.