Manual pump pre-orientable on the neck of a container

A manual pump adapted to be connected to the neck of a container, said pump comprising an axial pump body, a cap cooperating with said neck for fixing said pump body thereon, a piston slidable in said pump body in a reciprocating manner and having a free end part, an axially and angularly movable push-member loosely mounted onto the free end part of said piston for reciprocating said piston in said pump body, said push-member having at least an upper, non-depressed position and a lower depressed position, and at least a first angular position and a second angular position, said push-member having a distribution nozzle and at least one radial lug having a free end, a ring coaxially mounted with respect to said cap and said pump body and surrounding said piston at least partially, said ring having an inner wall with at least one longitudinal groove therein cooperating with said lug, whereby when said push-member is in said first angular position the lug is aligned with said groove permitting depression of said push-member and said piston to said lower depressed position, and at least one ramp therein having a lower part opening into said groove and an upper part angularly offset with respect to said groove, whereby rotation of said push-member to said second angular position while in said upper, non-depressed position aligns said lug with said upper part of said ramp preventing depression of said push-member and said piston, said upper part terminating in a radial abutment engageable by said lug to limit angular rotation of said push-member, said push-member being disconnected from said piston when said push-member is in said upper and second angular position and freely bearing against a head of said piston for the depression thereof, and slidable sealing means-disposed between said free end part of said piston and said push-member.