Hydraulic lash adjuster with oil reservoir separator

Claim 1

A hydraulic lash adjuster for a valve gear of an internal combustion engine, comprising: (a) body means having a blind bore formed therein, said body means including a contact surface adapted to contact associated engine valve gear components for receiving periodically applied forces; (b) plunger means slidably received in said body bore and defining, in cooperation with the blind end of said bore, a cavity, said plunger means including, (i) means defining a reaction surface adapted to contact associated engine valve gear components and transmit said periodically applied forces, (ii) a lower plunger member having an opening therein; (iii) an upper plunger member having an opening therein defined by a first internal surface and a first cylindrical surface adjacent the lower end of said upper plunger, said upper plunger further defining a transverse surface portion connecting said first internal surface and said first cylindrical surface, (iv) separator means for fluidly isolating said lower plunger opening from said upper plunger opening, said separator means including a downwardly opening cup shaped member having outer peripheral surface portions in fluid sealing engagement with said first cylindrical surface and said transverse surface portion, said cup-shaped member defining in cooperation with said lower and upper plunger members lower and upper fluid reservoirs, respectively; (v) one way valve means permitting fluid flow from said lower reservoir to said cavity; (c) said body means and said plunger means including means for receiving fluid under pressure from said engine and directing said fluid to said upper and lower fluid reservoirs; (d) said plunger means including means defining a passage communicating said upper reservoir with said reaction surface for directing fluid from said upper fluid reservoir to said reaction surface; and, (e) means biasing said plunger means outwardly of said cavity.