Door closer

Claim 1

A door closer comprising: a. an elongated cylinder having a closed end and means at its opposite end defining an axial opening of predetermined relatively large diameter and an annular shoulder adjacent said axial opening; b. piston means axially slidably mounted in the cylinder and including a piston and a cooperating piston rod of predetermined relatively substantially smaller diameter projecting axially outwardly through said relatively large diameter opening; c. mounting means on the closed end of the cylinder and on the piston rod outwardly of the cylinder for connection, one to a door and the other to a door frame, and arranged to dispose said cylinder at an oblique angle to the horizontal so that the cylinder slopes upwardly from the closed end thereof; d. an annular wiper element encompassing said piston rod for relative axial sliding movements therebetween; e. cup-shaped means in said cylinder having a top marginal edge portion disposed to engage said annular shoulder and a bottom portion having an axial opening therethrough for free reception Of said piston rod; f. a washer encompassing said piston rod axially inwardly of said bottom portion, said wiper element being disposed between said washer and bottom portion; g. and spring means interposed between said washer and said piston and yieldingly urging said piston toward said closed end of the cylinder; h. said cup-shaped means and washer supporting said wiper element in axially inwardly spaced relation to annular shoulder and cooperating with the cylinder to define, 1. an elongated primary chamber containing the piston and adapted to receive liquid therein to a predetermined normal level, 2. a relatively axially shorter overflow chamber adjacent said axial opening, and 3. passage means above said normal fluid level for free flow of liquid from said overflow chamber to said primary chamber.