US2203940A - Spraying machine - Google Patents

Description

June 11, 1940. T. F. BRACKETT SPRAYING MACHINE Filed April 11, 1938 vllllllllIIIIIIIIIIIIIIIIIIIII szw (Ittorneg Patented June 11, 1940 UNiTED STATES PATENT OFFICE SPRAYING MACHINE Tracy F. Brackett, Detroit, Micln, minor to General Motors Corporation, Detroit, Micln, a corporation of Delaware Application April 11, 1938, Serial No. 201,233

9 Claims. (01. 91-45) carriage moves. forward it is simultaneously shifted in proper relation to the spray equipment in compensation for'the curvature of the body surface in the direction of conveyor travel.

Additional objects and advantages will become apparent during the course of the followingspecification having reference to the accompanying drawing wherein Figured isa side elevation showing a body supportingcarrla'ge about to en:- gage with the elevating mechanism; Figure 2 is a perspective view illustrating the mounting of one of the camming plates and Figure 3 is an end view showing one of the carriage abutments or cam followers in engagement with the stationary riage is toward the left in Figure 1, the move ment being imparted through a tow bar 4 at the front end for connection with the continuously moving conveyor chain shown at t. This is the usual arrangement for transporting automobile bodies such as seen at it, through the paint shop for work at succeeding stations. At each of the several roof painting stations there may be located a reciprocating spray gun l mounted on a transverse track it substantially as disclosed in Patent No. 2,0t3,6t3.

According to conventional automobile body design, the roof panel is curved both longitudinally and transversely with the longitudinal curvature being most pronounced toward the rear of the body. The rear wall of the body can be sprayed by hand but in order to reduce the amount of hand spraying necessary and to carry machine spraying to a greater extent around the curvature than is ordinarily possible it is here proposed to compensate for the recession of the body surface by raising the work during conveyor travel so that the distance between the surface and the gun is maintained constant throughout the engagement by a cam follower.

operation for uniform coating. Such raising of the body as the rear portion comes into the spraying zone is preferably at one end only and, therefore, the carriage is tilted forward to avoid too wide a departure of the paint receiving sur- I face from a .plane which is substantially normal to the direction of spray discharge.

The shifting of the carriage may be accomplished by providing suitably contoured cam elements on either the carriage or the floor for m For economy it is preferable that cam followers be mounted on the several carriages for engagement with camrning devices on the floor adjacent the path of carriage travel. The cam follower may consist simply of a channeled bar 9 or the like fastened to the carriage 3 and projected beyond opposite sides. thereof. At each side of the carriage is located a cam plate III up which the followers ride during conveyor travel'for shifting the curved roof surface toward the gun I.

From the forward edge of the roof panel to the high point near the middle the surface is substantially flat and consequently no provision need be made for shifting the body; From the high. pointin the roof rearwardly the curvature recedes first to a smallamount and then at a higher rate to substantially the position of the window opening in the back panel. In conformity to this curvature the cam plate is given a contour such that the follower 9 rides up a gradual slope and finally a more pronounced slope to the high point of the cam corresponding to the point at which spraying is cut on. From this intermediate high point on the cam the follower rides down the opposite end of the cam until the rearwheels of the carriage are again in engagement with the conveyor track.

To keep down resistance it is proposed to provide either the can! follower or the cam with suitable anti-friction devices and in the embodiment illustrated the anti-friction devices are embodied in an endless roller chain it surrounding the cam plate it for movement thereon upon engagement by the follower 9. The chain it is of a conventional type and may consist of a series of spaced rollers successively connected by a group of links.

Inasmuch as. some bodies may not require elevation during roof spraying the cam plate it is pivotally mounted on the floor so that it can be swung down out of the path of the cam followers 8. The hinged mounting, as shown in the drawing, includes a series of spaced plates i2 bolted tothe cam plate l0 and pivoted or pinned plates I2 is a positioning bar ll which engages the floor as, seen in Figure 3 for holding the cam plate erect and for relieving the hinge pins from some of the strain. A diagonal brace rod i5 is hinged at its upper end to the plate \IB bolted to the cam" and at its lower end is secured by a removable pin I! to a floor plate l8. By removing the pin H the brace l5 can slide on the floor as the cam plate I0 is swung down.

I claim: v

1. Ina surface treating system of the character described, a traveling conveyor for work whose surface to be treated slopes in the direction of conveyor travel, a surface treating appliance positioned in given relation to one portion of the slope and means to maintain a substantially uniform relation between the appliance and the work surface throughout the length of the slope including work shifting mechanism constructed and arranged to shift the work in relation to the appliance in compensation for said slope. i

2. In a surface treating system, a traveling carriage for work whose surface to be treated is curved in the direction of carriage travel, a surface treating device positioned adjacent the path of carriage travel, a ramp having a contour substantially corresponding with said surface curvature and means onthe carriage to ride up said ramp as an incident to carriage travel for shifting the carriage in relation to said surface treating device.

3. In roof p nting apparatus of the character described, an overhead spray gun, a traveling continuous travel to the conveyor carriage so as to pass the body roof under said applicator, a v

pair of roof-contoured ramps on' opposite sides of conveyor carriage travel, and ramp riding means carried by the conveyor to raise one end of the conveyor carriage during its travel and maintain substantially uniform distance between the applicator and traveling roof.

5. For insuring proper spraying distance in v 2,208,940 to floor plates l3. Also bolted to the hinged I the spray painting of a curved body roof during body travel on a conveyor system, a traveling body carriage, a downwardly directed spray gun positioned above the line of carriage travel, a pair of ramps on opposite sides of the path of cariage travel through the spraying zone and a pair of ramp engaging followers on said carriage for elevation of the carriage relative to the gun during its travel.

6. In the spray painting of a curved body roof, a body conveyor system including conveyor track supporting structure, a roof spraying gun having its nozzle directed transversely to the path of conveyor travel, a traveling conveyor carriage and cooperating camming abutments on the carriage and supporting structure, respectively, so constructed and arranged as to ride one on the other incident to carriage travel through the spray zone for shifting carriage position in relation to the spray gun nozzle in compensation for roof curvature to maintain substantially uniform spraying distance between the curved roof surface and gun nomle.

'7. The structure of claim 6 together with antifriction load transmitting bearings carried by at least one of. said camming abutments for engagement with the other camming abutment.

8. In a surface finishing system of the character described, a traveling conveyor system, a spray gun adjacent thereto, a carriage engageable with the conveyor system to carry work into the spray zone of the gun and having a cam follower, a stationary camming member having an anti-friction chain tracking thereon and being positioned in relation to the gun for engagement by the follower to direct the traveling carrlage in a path predetermined in relation to the surface curvature of the work, said path of travel .resulting in substantially uniform spacing between the gun and the work surface being acted the work'into the spray zone of said gun, of

mechanism to elevate the carriage during its travel through the spraying zone including a stationary cam having a raceway of preselected contour, a series of rollers engageable with said raceway, an endless succession of links connecting successive rollers and a cam follower'mounted on the carriage for engagement with the chain assembly of rollers and links.

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