US2451391A

US2451391A - Apparatus for surface treating small objects

Info

Publication number: US2451391A
Application number: US534468A
Authority: US
Inventors: Keck Andrew
Original assignee: Curtiss Wright Corp
Current assignee: Curtiss Wright Corp
Priority date: 1944-05-06
Filing date: 1944-05-06
Publication date: 1948-10-12
Anticipated expiration: 1965-10-12

Description

Oct. .12, 1948. A. KECK APPARATUS FOR SURFACE TREATING SMALL OBJECTS 2 Sheets-Sheet 2 Filed May 6, 1944 FIG. 5

' FIG. 6

IN VEN TOR.

ANDREW KEGK ATTORNEY Patented Oct. 12, 1948 APPARATUS FOR SURFACE TREATING SMALL OBJECTS Andrew Keck, Gahanna, Ohio, assignor to Our-- tiss-Wright Corporation,

a corporation of Dela- Application May 6, 1944, Serial No. 534,468

2 Claims.

This invention relates to an apparatus for surface treating small objects and may be availed of with particular advantage in applying finishing and protective coatings to washers, rivets and the like.

When, for example, objects such as washers are to be surface treated by the application of a coating of paint, it is current practice to apply the paint in spraying or dipping operations. The application of the paint in a spraying operation is objectionable because the washers usually have surfaces of such contour or which are so located with respect to one another, or both, that some of such'surfaces escape the paint spray, particularly when the washers are painted in mass or batch quantities. When the dipping method of painting is employed, the washers are immersed in the paint and then hung to drain and dry. During the draining and drying operations, globules of paint frequently accumulate on their undersides. Such grounds may interfere with the intended use of the washers by preventing them from lying flat. Moreover, when the washers are painted in mass or batch quantities, they may adhere to one another and when this occurs and they are separated they are improperly or incompletely coated.

The principal object of the present invention, therefore, is to overcome the above objections, this object contemplating the application of the treating medium to the objects in such a manner that all exposed surfaces will be completely and uniformly treated.

A further object is to prevent the objects being treated from adhering to one another and to prevent localized accumulations of the treating material.

Other and further objects and advantages will be apparent from the following description, reference being had to the accompanying drawings wherein preferred embodiments of apparatus for carrying out the method are shown.

In the drawings:

Figure 1 is a perspective view of apparatus for carrying out the method, a portion of the apparatus being broken away to show the construction and arrangement of its various parts;

Figure 2 is a sectional view taken on line 2--2 of Figure 1;

Figure 3 is a fragmentary sectional view taken on line 3-3 of Figure 2;

Figure 4 is a view in section showing the treating apparatus suspended within a paint tank;

Figure 5 is a view in section of the preferred form of apparatus for carrying out the method;

pass through it;

Figure 6 is a sectional view taken on line 6--6 of Figure 5;

Figure 7 is a view' in section of another form of apparatus for carrying out the method; and

Figure 8 is a sectional view taken on line 8-8 of Figure 7.

I have found that quantities of small objects such as washers, rivets and the like may be rapidly and uniformly coated by dipping them in a liquid bath of the coating material and then, after removing them from such bath, directing a gaseous medium against them in such a manner that they are caused to traverse a prescribed path and during a part of their travel are elevated by the gaseous medium. When such objects are elevated and suspended by a gaseous medium, they will constantly change their positions. The said medium thus acts against all surfaces to effect a uniform distribution of the previously applied coating material while evaporating the solvents employed in connection with such material. The coating, therefore, will be uniformly distributed over the objects, will remain of a uniform thickness during the drying operation, and will be dried rapidly.

In Figure 1 of the drawings, there is shown one form of a device by which the method of my invention may be carried out. The device comprises a cylindrical container H which is closed at one end by a perforated bottom l2 and at its other end by a lid or cover M. A tube I5, attached to the sidewall of the container, extends from, adjacent the perforated bottom upwardly through the top of the container. The lower end N5 of the tube is formed to provide a jet for directing a sheetlike flow of gas into the container circumferentially, parallel to, and adjacent the perforated bottom l2. A manually operated valve H is connected to the outer end of the tube l5 and is used to control the quantity of gas, which in this instance is air, admitted to the tube from a suitable source (not shown) through a supply tube H3. The valve i1 is preferably a three-stage control, that is, it is designed so that it may be adjusted to a position in which it permits a large quantity of air to it is adjustable to a second position in which the flow of air is reduced, and to a third position in which the flow of air is cut oil. The purpose of this three-stage valve will be fully set forth hereinafter. The cover l4 fits the container tightly and is cut out at {9 to provide an opening through which the tube l5 extends. While it is preferred to extend the tube along the inside wall of the container, the device may be constructed in any suitable manner so that the air discharge jet causes the air to enter the container as previously described.

In operating my apparatus, I first introduce into the container a quantity of the objects which are to be painted and which, if necessary, have been first degreased. The cover is then placed on the container. For the best results thequantity of objects introduced into the container at any one time should not exceed two-thirds the total capacity of the container, the remaining space being utilized to permit the necessary free movement of the objects during the drying operation. The container is held in an upright position and the objects therein are immersed in the coating material by lowering the container into one compartment of a tank 20 (Figure 4) which contains a bath of the paint with which the objects are to be coated. When the container is in the bath,

the paint flows through the perforated bottom l2, into the container to completely cover the objects. After the objects have been immersed, the valve I! is opened to its low-stage and the air entering the container causes the objects to be thoroughly agitated. Agitation of the objects while they are immersed in the coating material insures that they cannot remain in a stacked condition and that all of the surfaces thereof will be covered, Preferably, the flow of air through the jet is now interrupted and the container is elevated above the bath and suspended from the edge of the tank, as indicated in dotted lines, by a supporting bracket 2| which is suitably. secured to, and forms a part of, the container.

This operation permits the excess paint to drain from the objects and container back into the tank. After the objects have drained, but before the paint thereon begins to dry, the container is removed from above the bath and is hung bythe bracket 2| in the other compartment of the tank, as indicated, and the valve I 1 is opened to its high-stage; The sheet-like, high-velocity stream of air entering the container adjacent its'bottom keeps the objects in continuous motion, thereby causing any excess paint still remaining on them to be removed. The air impart to the mass of objects in the container and as the objects pass the jet, the air lifts and supports them while turning them. Thus all surfaces of the objects are uniformly subjected to the drying action of the air whileat the same time. the paint adhering to such surfaces is uniformly distributed.

The air is permitted to flow until the coating on the objects has completely dried. The openings in the bottom of the container provide for the escape of the exhaust air and any excess paint removed from the objects by the air.v

In Figures 5 and 6, there is shown another device for carrying out the surface treating operation, which device may be preferred because it is capable of accommodating a greater quantity of objects and because collision between the objects during their treatment is minimized. This de vice comprises a cylindrical container 25 having an inverted conicalbottom 26 with an air jet 2'! in the tip thereof. A valve Ila. is connected to the lower end of the jet 21. An open ended tube 28 is'supported centrally and vertically within the container by bolts 29. A cover 30, including a centrally disposed deflector 3| and an outer depending skirt 32, tightly fits the top of the container. The deflector is preferably cone-shaped and of wood or other cushioning material. The skirtextends downwardly outside the container and forms a deflector for exhaust air which may s a rotary motion 7 escape through outlet ports 33 which are formed in the container near the top thereof. The length and diameter of the inner tube 28 is such thatit and the container form a pair of

chambers

34 and 35 which are interconnected by

passages

36 and 31, The device is provided with a bracket 38 by which it may be supported from a vertical panel or by the side of the paint tank 20.

This device is used only for drying the coating material upon the objects. In using it, the objects are first dipped in the coating material and drained, and prior to hardenin of the coating material on the objects, the latter are placed in the container. The cover is then fitted securely to the container and the valve Ila is opened. The

jet 2'! is positioned to direct a stream of air upwardly and centrally through the inner chamber 34.: The deflector 3| breaks up the air stream and the exhaust air is discharged from the container through the openings 33 being deflected down:- wardly by the skirt 32. The. air outlets arepreferably positioned as shown inthe drawings but their location is not critical. They may, for example, be formed in the cover. The cone shaped bottom 26 forms a receptacle 39 which directs the objects therein toward the center of the container where they are picked up by the air stream issuing from the jet 2! and are blown upwardly through the chamber 34, directed outwardly by the deflector, and returned by gravity through the. outer chamber 35 to the receptacle 39 so. that they may again be picked up by the air stream to start anew the cycle described. The device will operate without the inner tube 28 but its use is highly desirable because it minimizes collisions between the rising and descending objects.

In Figures 7 and 8,.a more'simplified form of device is shown. In this embodiment the casing is provided by a pair of cooperating sections 40 and 4|. The said sections are secured together by a central bolt 42 and in chamber. A jet 43 having a valve l 1b extends into the casing through the section 40. and directs a stream of air into the device at the lower side of the drying chamber and circumferentially of the annular Wall thereof. The air 7 is directed against the objects in such manner as to elevate them and while they are elevated to turn them, thereby exposing 'all of their surfaces to the drying and coating-distributing action of the gaseous medium. The apparatus is highly efiective and enables the. objects to be coated rapidly, titles.

While the invention is described in connection [with an apparatus for paintin objects, it is to be only and that the invention may be availed of with equal advantage in treating objects which are intended to be impregnated or impregnated and coated. s

I claim as my invention:

1. .Apparatus for use objects of the character described, comprising a provide an annular dry- I V entering the V drying chamber is thus adapted to cause the obeconomically and in mass or batch quanunderstood that this is by way of illustration in coating manufactured container into which said objects are introduced, said container having a perforated bottom through which coating material containing a liquid solvent may be introduced into the container to coat said objects and may thereafter drain to remove excess material from said objects, and means for directing a jet of a gaseous medium into the container in such manner as to elevate said objects and thereby increase the effectiveness of the gaseous medium in evaporating the solvent of the coating material on said objects.

2. Apparatus for coating manufactured objects such as washers comprising a first container for a coating material containin a liquid solvent and second container into which said objects may be introduced, said second container having a perforated bottom wall and being adapted for immersion in a body of said coating material in said first container, said perforated bottom wall permitting excess coating material to drain from the objects when the second container is removed from the coating material in said first container, and means for directing a jet of a gaseous medium into the second container in such a manner as to elevate said objects and thereby increase the eifectiveness of the gaseous material in evaporating the solvent of the coating material.

ANDREW KECK.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS