Piston rod rotation features in a spray fluid pump

Patent metadata

Field	Value
Publication number	US-12116997-B2
Application number	US-201917297321-A
Country	US
Kind code	B2
Filing date	Nov 26, 2019
Priority date	Nov 27, 2018
Publication date	Oct 15, 2024
Grant date	Oct 15, 2024

Abstract

A piston rod (27) for a spray fluid pump includes an interior pumping chamber (40), one or more channels (50) formed on the exterior of the piston rod, and one or more side bores (32) extending through the piston rod and in fluid communication with the interior piston chamber and one or more channels. The one or more channels (50) extend at least partially axially and are open along a length of the channel. The one or more channels are angled offset with respect to the reciprocation axis for imparting a rotational moment on the piston rod to cause rotation of the piston rod during reciprocation of the piston rod. A spray fluid pump comprising such piston rod is also disclosed.

First claim

The invention claimed is:

1. A piston rod elongate along a reciprocation axis, the piston rod comprising:
an interior piston chamber open in a first direction along the reciprocation axis and closed in a second direction along the reciprocation axis;
one or more channels formed on an exterior of the piston rod; and
one or more side bores extending through the piston rod and fluidly connecting the interior piston chamber with the one or more channels respectively, wherein each of the one or more side bores is associated with a respective channel of the one or more channels, and each of the one or more side bores is angled relative to the reciprocation axis to direct flow of paint in a downstream direction and into the respective channel as the paint exits the side bore, and wherein each of the one or more side bores is angled offset relative to the reciprocation axis to direct the flow of paint along a vector to impart a moment on the piston rod;
wherein each channel of the one or more channels extends at least partially axially and is open along a length of the channel;
wherein each of the one or more channels is angled offset with respect to the reciprocation axis; and
wherein the flow of paint ejected from each of the one or more channels imparts a rotational moment on the piston rod during pumping.

2. The piston rod of claim 1 , wherein each of the one or more channels includes a downstream lip, and wherein the flow of paint ejects from each channel at the downstream lip.

3. The piston of claim 2 , wherein the downstream lip defines a downstream terminus of the channel.

4. The piston of claim 3 , wherein a downstream terminus of each channel is formed by a transition at which a diameter of the piston rod transitions from a wider diameter to a narrower diameter.

5. The piston rod of claim 1 , wherein each of the one or more channels extends straight along the length of the channel.

6. The piston rod of claim 1 , wherein each of the one or more channels extends straight.

7. The piston rod of claim 1 , wherein a depth of each of the one or more channels changes along the length of the channel.

8. The piston rod of claim 1 , wherein a downstream end of each of the one or more channels terminates in a transition formed on the piston rod, and wherein a diameter of the piston rod reduces from an upstream end of the transition to a downstream end of the transition along the transition.

9. The piston rod of claim 1 , wherein the one or more side bores comprises at least three side bores, the one or more channels comprises at least three channels, and the at least three side bores are respectively fluidly connected to the at least three channels.

10. The piston rod of claim 9 , wherein the at least three side bores are evenly arrayed about the piston rod, and the at least three channels are evenly arrayed about the piston rod.

11. The piston rod of claim 1 , wherein a first seal is captured on an exterior of the piston rod.

12. The piston rod of claim 1 , wherein a bowl is formed at an intersection between a side bore of the one or more side bores and a channel of the one or more channels.

13. The piston rod of claim 1 , wherein:
the piston rod has a first end, a main body, and a second end;
the first and second ends are located at opposite axial ends of the main body;
the main body includes an elongated cylindrical surface;
the first end includes a piston coupling; and
the second end includes the interior piston chamber, the one or more side bores, and the one or more channels.

14. The piston rod of claim 13 , wherein the second end has a first diameter and the main body has a second diameter, the first diameter larger than the second diameter.

15. The piston rod of claim 14 , wherein a transition is formed between the second end and the main body, the transition sloped between the first diameter and the second diameter.

16. The piston rod of claim 13 , wherein each channel of the one or more channels has a variable depth.

17. The piston rod of claim 13 , further comprising:
a manifold portion is formed on the second end of the piston rod;
wherein the manifold portion has a first diameter and the main body has a second diameter;
wherein the first diameter is larger than the second diameter; and
wherein at least part of each channel of the one or more channels extends into an exterior surface of the manifold portion.

18. A piston rod elongate along a reciprocation axis and configured to reciprocate along and rotate on the reciprocation axis, the piston rod comprising:
a first end, a main body, and a second end located at an opposite end of the main body from the first end, the main body including an elongated cylindrical surface;
a piston coupling including a head and a neck disposed at the first end;
an interior piston chamber formed in the second end and open in a first direction along the reciprocation axis and closed in a second direction along the reciprocation axis;
one or more channels formed on an exterior of the piston rod; and
one or more side bores extending through the piston rod and fluidly connecting the interior piston chamber with the one or more channels respectively, wherein each of the one or more side bores is associated with a respective channel of the one or more channels and each of the one or more side bores is angled offset relative to the reciprocation axis to direct the flow of paint along a vector to impart a moment on the piston rod to induce rotation of the piston rod;
wherein each channel of the one or more channels extends at least partially axially and is open along a length of the channel;
wherein each of the one or more channels is angled offset with respect to the reciprocation axis; and
wherein the flow of paint ejected from each of the one or more channels imparts a rotational moment on the piston rod during pumping to induce the rotation of the piston rod.

Assignees

• Graco Minnesota Inc

Inventors

• Horning Jeromy D
• Legatt August F
• Paulson Justin G
• Thompson David J

Classifications

• F04B53/144 Primary

  Adaptation of piston-rods · CPC title

• F04B15/02

  the fluids being viscous or non-homogeneous · CPC title

• B05B9/0413

  with reciprocating pumps, e.g. membrane pump, piston pump, bellow pump (B05B9/0409 takes precedence) · CPC title

• F04B53/148 Primary

  the piston being provided with channels which are coacting with the cylinder and are used as a distribution member for another piston-cylinder unit · CPC title