Hydraulic lash adjuster with oil reservoir separator

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.