US3672569A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Electrostatic spray gun nozzle and air cap
Assignee: Graco Inc
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Filing: 1970-07-16
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Granted: 1972-06-27
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Expires: 1990-07-16
Abstract
Abstract In an electrostatic spray gun, the nozzle serves as the electrostatic charging electrode with a recessed forwardly facing surface that joins a first sharp annular edge adjacent the coating material ejected from the nozzle and a second annular sharp edge adjacent the ejected atomizing air. An air cap surrounding the nozzle provides an annular parallel air ejection passage. Preferably, the sharp edges of the nozzle protrude slightly forwardly of the termination of the air ejection passage formed by the air cap.
Inventors
- 👤 Robert G Smead
- 👤 Louis J Bentsen
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-23 21:28
CPC Classifications
B; B05; B05B; B05B5/00; B05B5/025; B05B5/03
Claims Analysis
Total Claims: 14
Claim 1
Independent Claim
121 words
An electrostatic spray gun comprising: an electrically conductive nozzle having a center line through which coating material is ejected, said nozzle having an internal orifice surface symmetrically positioned around the nozzle center line and terminating at a first plane perpendicular to said center line, an outer surface symmetrically positioned around the nozzle center line and terminating substantially at said perpendicular plane, and a recessed forward facing surface joining said internal orifice surface and joining said outer surface to form inner and outer sharp edges therebetween, and an air cap through which gas is ejected having an internal orifice surface surrounding said nozzle and substantially parallel to said center line, said surface terminating in a second plane perpendicular to said center line.
Claim 2
Dependent Claim
121 words
An electrostatic spray gun comprising: an electrically conductive nozzle having a center line through which coating material is ejected, said nozzle having an internal orifice surface symmetrically positioned around the nozzle center line and terminating at a first plane perpendicular to said center line, an outer surface symmetrically positioned around the nozzle center line and terminating substantially at said perpendicular plane, and a recessed forward facing surface joining said internal orifice surface and joining said outer surface to form inner and outer sharp edges therebetween, and an air cap through which gas is ejected having an internal orifice surface surrounding said nozzle and substantially parallel to said center line, said surface terminating in a second plane perpendicular to said center line.
Claim 3
Dependent Claim
21 words
An electrostatic spray gun as specified in claim 1, wherein said nozzle outer sharp edge protrudes forwardly of said second plane.
Claim 4
Dependent Claim
21 words
An electrostatic spray gun as specified in claim 1, wherein said nozzle inner sharp edge protrudes forwardly of said second plane.
Claim 5
Dependent Claim
27 words
An electrostatic spray gun as specific in claim 1, wherein said first plane is positioned at least three thousands of an inch forwardly of said second plane.
Claim 6
Dependent Claim
28 words
An electrostatic spray gun as specified in claim 1, wherein said first plane is positioned not more than ten thousands of an inch forwardly of said second plane.
Claim 7
Dependent Claim
19 words
An electrostatic spray gun as specified in claim 1, wherein said air cap is composed of electrically non-conductive material.
Claim 8
Dependent Claim
105 words
An electrostatic spray gun comprising: an electrically conductive nozzle having a center line through which coating material is ejected, said nozzle having an internal orifice surface symmetrically positioned around the nozzle center line and terminating at a first ionizing means, an outer surface symmetrically positioned around the nozzle center line and terminating at a second ionizing means, and a recessed forward facing surface formed by joining said internal and external surfaces, and an air cap through which gas is ejected having an internal orifice surrounding said nozzle and substantially parallel to said center line, said surface terminating in a plane perpendicular to said center line.
Claim 9
Dependent Claim
105 words
An electrostatic spray gun comprising: an electrically conductive nozzle having a center line through which coating material is ejected, said nozzle having an internal orifice surface symmetrically positioned around the nozzle center line and terminating at a first ionizing means, an outer surface symmetrically positioned around the nozzle center line and terminating at a second ionizing means, and a recessed forward facing surface formed by joining said internal and external surfaces, and an air cap through which gas is ejected having an internal orifice surrounding said nozzle and substantially parallel to said center line, said surface terminating in a plane perpendicular to said center line.
Claim 10
Dependent Claim
17 words
The electrostatic spray gun of claim 7, wherein the first and second ionizing means are sharp edges.
Claim 11
Dependent Claim
20 words
The electrostatic spray gun of claim 8, wherein both of the sharp-edged ionizing means protrude forward of the air cap.
Claim 12
Dependent Claim
17 words
The electrostatic spray gun of claim 8, wherein the air cap is composed of electrically non-conductive material.
Claim 13
Dependent Claim
24 words
The electrostatic spray gun of claim 9, wherein the protruding sharp edges extend at least three-thousandths of an inch forward of the air cap.
Claim 14
Dependent Claim
25 words
The electrostatic spray gun of claim 9, wherein the protruding sharp edges extend not more than ten-thousandths of an inch forward of the air cap.
References Cited (Backward Citations)
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1975-06-27 | 1975-12-27 | 1976-06-27 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1979-06-27 | 1979-12-27 | 1980-06-27 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1983-06-27 | 1983-12-27 | 1984-06-27 | $7700.00 | Window Closed / Lapsed |