Patent ID: 6994013

Claim:
A single-acting cylinder-piston unit of plunger type, comprising a cylinder ( 1 ) closed at one end by a base ( 4 ) and containing a slidable cylindrical rod ( 5 ), the inner end of which presents two adjacent circumferential grooves ( 18 , 28 ), the first ( 18 ) of which acts as a final seat for a split ring ( 8 ) defining the limit of the outward stroke of said rod, and the second ( 28 ) of which acts as a temporary seat for the said split ring enabling the rod with the split ring mounted thereon to be inserted into the cylinder, said second groove ( 28 ) being situated at the inner end of said rod while said first groove ( 18 ) is situated more towards the opposite end of said rod, in proximity to said base there being provided a counteracting member which during the final stage of the total insertion of the rod into the cylinder is arranged to interfere with the split ring in order to cause it to transfer from said second groove to said first groove, wherein said second groove is configured to form a retention seat for said split ring and is dimensioned to hold said split ring so that the external generators of said split ring lie below the outer surface of said rod, thereby allowing said split ring to be inserted with said rod into said cylinder during assembly of said cylinder-piston unit, and said first groove is dimensioned to hold said split ring so that the external generators of said split ring lie beyond the outer surface of said rod.