US2072948A - Spray coating machine - Google Patents

Description

March 9, 1937.

FIG. 1.

F. A. GEFFS SPRAY COATING MACHINE Filed Npv; 30. 1931 4 Sheets-Sheet l "gmmtoc March 9, 1937. GEFFS 2,072,948

SPRAY COATING MACHINE Filed Nov. 30, 1931 4 Sheets-Sheet 2 FIG. Z.

attomwqs March 9, 1937. F. A. GEFFS SPRAY COATING MACHINE Filed NOV. 30, 1931 4 Sheets-Sheet 3 gwmm am 4. W

March 9, 1937. F. A. GEFFS SPRAY COATING MACHINE Filed Nov. 30, 1931 4 Sheets-Sheet 4 Patented Mar. 9, 1937 UNITED STATES 2,072,948 SPRAY COATING momma Frank A. Gefls, Toledo, Ohio, assignmto The De Vilbiss Company, Toledo, Ohio, a corporation of Ohio Application November 30, 1931, Serial No. 577,917

6 Claims.

This invention relates to a spray coating machine which is adapted to apply a coating to a succession of articles as they travel therethrough. In the production of lumber, for example, there are many reasons in favor of applying a priming coat to the individual pieces before they leave the mill and, in applying such priming coat, the present invention may be used with marked advantage.

The general object of the invention is to provide a machine by which articles of the character stated may be coated economically on a large scale. In the preferred form of the invention, the articles are carried through the machine by a continuously traveling conveyor and during such transit every surface of each article is completely coated by means of sprayguns.

which are automatically turned on and off at the proper time by means actuated by the article itself. Since, in-many cases, the pieces of lumber or other articles are too light to be eflicient in tripping air valves directly or in operating an electric switch, it is preferred to employ a photoelectric relay for that purpose.

'The detailed construction and operation of the invention in its present embodiment will be more particularly described in connection with the accompanying drawings, in which- Figure l is a side elevation of the invention;

Figure 2 is a section taken on the line 2-2 of Fi 1; v

Figure 3 is a section taken substantiallyon the line 3-3 of Fig. 1;

Figure 4 is a perspective view of the means for controlling the spray guns, including trip mechanism and a photo-electric relay actuated thereby.

The machine to which the invention relates comprises a spray booth or chamber In which is preferably supported above the floor or ground by legs ii and through which pieces of lumber l2 or other articles are fed. The booth is therefore provided'with an inlet l3 and an outlet l8. Suitable adjustable guides l5 may be provided for directing the articles I2 into the booth.

For feeding the articles l2 into the booth, there is provided an endless conveyor [6 which passes over the rolls l1 and I8 mounted in a frame IS. The conveyor I B is driven by a suit- 5 able motor 20 through speed reduction gearing 2!. p

Mounted on one end of the shaft 22 which supports the roll I8 is a drive sheave 23 which is connected by a belt 24 to a similar sheave mounted on a colmter-shaft 25. The shaft 25 gizing each of the solenoids 53 to operate the,

through suitable driving connections 25 drives the delivery mechanism which is mounted on a frame 21 in position to receive the pieces l2 as they are delivered from the spray booth. This delivery mechanism includes rolls 23 and 29 con 6 nected by a conveyor belt 30 which is provided with prongs 3| so as to support the pieces l2 with their undersides freshly coated wlthout'disturbing thecoating.

The means for conveying the articles l2 through the spray booth includes series of star wheels 32 secured to' shafts 33. Between the shafts 33 idler rolls 34 may be provided to aid in supporting the articles, but it is not desirable to have any of these rolls in position to contact with the under surface of an article after it is coated. For driving shafts 33, each of these shafts is provided at one end with a sprocket wheel 35, all of these sprocket wheels being connected by a chain 36 and driven from the roll 28 by means of sprocket gearing 31. In order to insure engagement of the upper lap of the chain 36 with the sprocket wheels 35, a series of idler sprocket wheels 38 are provided, underneath which the chain passes.

The coating material is contained in a tank 39 from which it is delivered through conduits 40, valves 4| and conduits 42 to the several spray guns 43 which are mounted for universal adjust- I ment on the bars 44, so that they may be brought into the proper relative position according to the size and shape of the articles being coated. Compressed air is supplied through a conduit 45, valve 46, pressure regulator 41 and conduit 48 to the upper surface of the liquid in the tank 39. Compressed air is also supplied through a pressure regulator 49, conduits 50, Valves 5| and conduits 52 to the air nozzle of each spray gun. Compressed air for controlling the needle valve in each spray gun is supplied through con-, duits 53 and 54 leading to a control chamber 55 within which is a valve 56 mounted in a valve housing 51. When the valve 56 is opened the air passes from the valve chamber through conduit 58, valves 59 and conduits 60 to the spray nozzles 33 to open the same.

The valve 56 is normally closed but may be opened by means of a lever 6|. The lever 6| is normally held out of contact with the valve 56, as shown inFig. 4, by means of a spring 62, but is moved to open the valve 56 by means of a solenoid 63, whenever the latter is energized.

For insuring an accurate and positive control of the spray guns, provision is made for enerrespective spray guns while a piece of lumber l2 or other article is passing the same. As illustrated in Figs. 3 and 4, this result is eflected through the medium of a photo-electric tube 84 mounted within a hood 85 and adapted to receive a ray of light through an aperture 66 from an electric lamp 81 in a box 88. As the light strikes the tube 64, it sets up a current through the latter, which energizes a sensitive relay, including an amplifier, in the box 68. The leads to the relay are so connected that when the relay is energized it opens the circuit through the solenoid 83, and when the relay is de-energized, it closes the circuit through the solenoid. Current for the solenoid is supplied through a switch box 18, line H, the relay in box 69, and a line 12. Current is supplied continuously through box 89, cable 13, outlet box I4 and line 15 to the lamp 61. A connection is made from the sensitive relay through cable 13, box 14 and line 16 to the photoelectric tube 64.

The passage of light through the aperture 86 to the photo-electric tube 84 is controlled by a semaphore I! carried on an arm 18 which is secured to a rock shaft 18. A spring normally holds the rock shaft 19 with the semaphore in position to uncover the aperture 66, as shown in full lines in Fig. 4. In this position the sensitive relay is energized and the circuit through the solenoid is open. The shaft 19 carries a trip arm 8| which projects into the path of the article I2 to be coated. As the article engages the arm 8| it rocks the shaft so that the semaphore TI covers the aperture 68, de-energizing the relay and closing the circuit through the solenoid 63. The spray gun is then operated until the article has passed by the trip arm 8|, whereupon the spring 8|] returns it to normal position and causes the spray gun to cease operation.

It will be noted that there are two photoelectric relays, one for controlling a set of spray guns for coating the upper surface of the articles and the other for controlling a set of spray guns for coating the bottom surface. Either set of spray guns may be adjusted to coat the side edges and ends of the articles. It is also desirable that one or both sets of spray guns be controlled by a double trip as shown in the left hand portion of Figs. 1 and 2. That is, the shaft 19 is connected with a counter-shaft 19 having a trip arm 8|. Thus as the end of the article I! strikes the first trip arm 8|, the spray guns are turned on in time to spray the front end of the article as well as the bottom thereof and the spray is continued until the rear end of the article leaves the trip arm 8|.

In order to conserve the surplus coating material, the bottom 83 of the spray booth has a gradual slope toward one corner where the excess material may be drawn off through an outlet 84 and used again. In order to carry away the fumes of vaporized spraying material, an antechamber 85 is provided at one side of the booth l0 and in communication therewith and a strong draft is provided by a fan 86 to discharge the vapor through an exhaust flue 8'1.

From the foregoing description, it will be seen that I have provided a spraying machine in which the operation of the spray guns is controlled automatically in accordance with the progress of each successive article through the spray booth. Each article is completely coated with a minimum expenditure for labor and mate rial. By the use of such a machine in treating lumber, each piece'may be completely protected by a priming coat before it leaves the mill and sold to the ultimate consumer at a price no higher than would be paid by the customer for unpainted lumber plus the priming of one side only on the job, as is customary, and there will still be left an extra proiit for the lumber dealer.

While I have shown and described the invention with particular reference to the priming of lumber, it is apparent that it may be used for spray coating other articles, and that the construction may be considerably modified without departing materially from the scope of the appended claims.

What is claimed is:

1. In a spray coating machine, spray discharging means, means for conveying articles across the path of the spray discharge, electric means operable when energized to open the spray discharge means and maintain it open as long as the electric means remains energized, successive interconnected trip arms in the path of the articles, and means connected with said trip arms to maintain a circuit through said electric means from the time the first trip arm is engaged by the front end of an article until the last trip arm is released from the rear end of said article.

2. In a spray coating machine, spray discharging means, a valve shiftable to turn the discharge on or off, said valve being biased to one position,

photo-electric control means for said valve, and means, including a semaphore and a trip member actuated by an article in transit to render the photo-electric control means effective to shift said valve to the opposite position.

3. In a sprayv coating machine, a spray gun, means for conveying an article past the spray gun, a normally closed control valve for said spray gun, a photo-electric relay controlling the position of said valve, a semaphore associated with said relay, a trip controlling the position of the semaphore and actuated by said article to maintain the semaphore in position to cause the photo-electric relay to maintain said valve in open position while said article is passing the spray gun, and means for automatically moving the semaphore to valve closing position as soon as said article has completed its passage past the spray gun.

4. In a spray coating machine, a spray gun, means for conveying an article past the spray gun, a normally closed control valve for said spray gun, a photo-electric relay controlling the position of said valve, a semaphore associated with said relay, two successive trip arms in the path of said article, means controlled by said trip arms through the semaphore to cause the photo-electric relay to open said valve and maintain it in open position from the time when the front end of said article passes the first trip arm until the rear end of said article passes the second trip arm, and means for immediately there: after automatically moving the semaphore to valve closing position.

5. In a spray coating machine, a spray gun, means for conveying an article past the spray gun, a normally closed control valve for said spray gun, two successive trip arms in the path of said article, means to open said valve and maintain it in open position from the time when the front end of said article passes the first trip arm until'the rear end of said article passes the second trip arm, and means for immediately thereafter automatically closing said valve.

amass-a 6. In a spray coating machine, the combination with spray fume exhamt means. of means for conveying articles through the effective range otsaidexhaustmeansdpmgunssettodib charge material against diflerent faces 0! each article during its transit, said guns being disposed outside said exhaust means and adapted to discharge into the range of said means. a

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