US1786394A - Air brush - Google Patents

Description

R. W. TRACY Dec. 23, 1930.

AIR BRUSH Filed Jan. 10, 1929 Patented Dec. 23, 1930 UNITED STATES PATENT OFFICE ROBERT W. TRACY, OF TOLEDO, OHIO, ASSIGNOR TO THE DE VILBISS COMPANY, OF TOLEDO, OHIO, A CORPORATION OF OHIO AIR 3111151:

Application filed January 10, 1929. Serial in. 331,570.

This invention relates to a spraying de vice of the type commonly known as an air brush, and it is constructed with special reference to its use in the art of spray painting.

In spray painting, as the fluid paint leaves the nozzle, there is always a tendency for it to spread or scatter in all directions from the center line of the stream and it is therefore desirable to provide means to flatten the stream so that it may be caused to assume the shape of a fan and so that the paint, as it reaches the object to be painted, will be applied thereto in the form of a thin, flat, uniform sheet. Various devices have heretofore been proposed for flattening the paint stream by means of supplemental air jets directed against the sides thereof, but the operation of such devices has been more or less imperfeet because of the great difficulty in maintaining precisely the correct pressure on the supplemental jets or in producing jets of the proper shape and direction to flatten the stream into a sufficiently thin sheet without splitting the same or at least making'some portions thereof thinner than other portions.

It is with the above conditions in mind and with the object of overcoming the difliculties mentioned, that the present invention has been perfected.

The specificconstruct-ion of the invention in its. present form and the principles of its operation will be explained particularly in connection with the accompanying drawing, the single figure of which represents a central longitudinal section through. the discharge end of the spray head.

In the spray head in connection with which the invention isillustrated, the body portion 1 is provided with a central passageway 2 through which the paint-passes. liquid nozzle 3 is secured to the body portion at the outlet end of the passageway 2 by means of a union 4. This nozzle 3 has a tapered outlet 5 through which the flow is controlled by means of a needle valve 6.

An'air nozzle 7 encompasses the liquid nozzle 3 and is secured to the body 1 by means of a union 8. This air nozzle is so designed as to leave an air chamber 9 surrounding the liquid nozzle 3 and air under pressure is supplied through a passageway 10 in the body 1.

from the chamber 9 and each of these passages has two outlets 13 and 14. These outlets 13 and 14 converge toward their mouths and both incline toward the paint laden stream, so that the air streams emitted from the outlets 1'3 and 14, as shown by the dot and dash lines, merge together before they strike the paintladen stream and are both. flattened out to form a single fan-shaped supplemental jet oneach side of the mainstream. In this manner the effect of each supplemental jet is softened so that it will not penetrate or scatter the aint stream, and a further eflect of the con uence of the two air streams emitted from the outlets 13 and 14 is to spreadthe jets around the paint stream so that they sub: stantially envelop the same and at the same time flatten it into the shape of a comparatively thin fan of uniform thickness.

While I have shown and described the invention in connection with one specific type of spray head, it is obvious that the invention is not limited thereto, but may be used in connection with an spray head using compressed air'or a similar medium for effecting the discharge. of the material stream. It is to be understood, therefore, that the invention includes all such modifications as fall within the scopeof the appended claims.

What I claim is:

1. An air brush provided with means for discharging a material laden stream by the use of air under pressure, and meansfor discharging supplemental air jets against oppo- 2. In an air brush, means for discharging a material laden stream by the use of air under pressure, and means for discharging supplemental air jets against opposite sides of the main stream to flatten the same, said last means including a set of at least two air discharge orifices at each of opposite sides of the main stream with the lines of discharge of the outer orifices of the two sets converging and intersecting at a point on the axis of the main stream and with the lines of discharge of the next orifice of each set ntersecting the line of discharge of the outer orifice of the respective set at a point spaced from but adjacent to the main stream whereby the supplemental air streams of each set merge and form fan-like air streams before striking the main stream.

In testimony whereof I have hereunto signed my name to this specification.

ROBERT W. TRACY.

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