Patent ID: 11891992
Assignee: GRACO MINNESOTA INC.
Field: Engines, pumps, turbines (Mechanical engineering)
Classification: CPC F | IPC F

Claim 0:
1. A piston for a displacement pump configured for pumping paint, the piston comprising:
a piston rod elongate along an axis between a first end and a second end;
a piston cap connected to the first end and configured to interface with a drive that causes reciprocation of the piston along the axis, the piston cap comprising:
a cap body having a socket extending into the cap body;
a cap shoulder formed radially between the socket and an exterior of the cap body;
a cap neck extending from the cap body and disposed at an opposite end of the cap body from an opening of the socket;
a cap head connected to the cap neck and disposed at an opposite end of the cap neck from the cap body, wherein the cap head extends radially outward from the cap neck such that an axial gap is formed between the cap head and the cap body;

a central bore extending into the second end and configured to receive the paint, the central bore including an opening formed at the second end;
at least one port having a port opening formed on an exterior of the piston rod and oriented radially relative to the axis, the at least one port extending radially into the piston rod and intersecting with the central bore to be in fluid communication with the central bore, the at least one port configured to expel the paint from the central bore;
a support cylinder extending from the second end and disposed between the second end and the at least one port, wherein the central bore extends through the support cylinder, and wherein a relief configured to receive a first dynamic seal is formed about the support cylinder;
a flange projecting outward relative to the support cylinder, the flange disposed at a downstream end of the support cylinder; and
a wear sleeve mounted on the piston rod body and overlapped by the cap shoulder along the axis, the wear sleeve formed from ceramic, wherein the at least one port is disposed axially between the flange and the wear sleeve;
wherein the piston rod is removably connected to the piston cap by a shank of the piston rod extending into the socket, the piston rod removably connected to the piston cap by interfaced threading.