Abstract: Hydraulic tappet comprising a cup member, the latter sliding in a seat and housing a second cup member sliding in relation to the first in such a manner as to form a first chamber, and a flexible annular member located essentially inside the said second cup member in such a manner as to form a fluidtight second chamber connected hydraulically to the said first chamber; the said two chambers being filled with activating fluid the flow of which from the said second to the said first chamber being controlled by an on-off member.

Abstract: Hydraulic tappet essentially comprising a first cup member sliding in a seat; a second member sliding axially in relation to the first; a third annular member located inside the said first cup member and having a sleeve, inside the inner bore of which the said second member slides axially, and a ring projecting radially from the said sleeve and connected in fluidtight manner to the side wall on the said first cup member in such a manner as to form a first chamber for fluid under pressure; and a fourth annular member made of flexible material and located essentially inside the said first cup member and outside the said sleeve on the said third annular member in such a manner as to form a second activating fluid chamber connected hydraulically to the said first chamber over a duct with an on-off member.

Abstract: There is disclosed a hydraulic tappet comprising a bucket element which slides inside a seat and houses a second bucket element that slides over an annular member integral with the first bucket element in such a manner as to form a first chamber. A deformable annular element is arranged around the second bucket element in such a manner so as to form a second fluid tight chamber connected hydraulically to the first chamber. The chambers are filled with drive fluid and the passage of the fluid from the second chamber to the first chamber is controlled by an on-off member.