GB806765A - Improvements relating to apparatus for electrostatically spray-coating large objectswith paints, lacquers or the like - Google Patents

Abstract

<PICT:0806765/III/1> <PICT:0806765/III/2> An apparatus for electrostatically spraycoating large bodies, e.g. motor vehicle bodies 39, with paint or lacquer comprises a plurality of spraying electrodes 33, or groups of electrodes, movable simultaneously along intersecting paths 41 ... 43, and means for moving the electrodes 33, or the groups, in interdependence so that they are maintained a minimum distance apart. The apparatus comprises a gantry 6 ... 8 on which the electrodes 33 are mounted by arms 32 connected to carriages 9 ... 11 each comprising a plate 25, Fig. 5, running on rails 26, 27 and moved in either direction by a pin 24 fixed to an endless chain 22 and engaging a slot 23. In the embodiment the apparatus operates as follows:-A motor drives an endless chain 13 to rotate a shaft 46 and drive endless chains 14, 16 which rotate wheels 21 about which the chains 22 pass. Carriages 9, 10 are thus moved, and with them the carriage 11 through chains 18, 19 and a shaft 47. The linkage is such that the carriage 9 moves from the position shown in Fig. 1 to either end of the path 41, and back, while the carriages 10, 11 move up (or down) the paths 42, 43, respectively. In a modification, a single chain joining the carriages 10, 11 is employed and runs over wheels on the shafts 46, 47, the carriage 9 being secured to the middle of the chain. The separate chains 22 for the carriages 10, 11 are dispensed with, along with the chains 13, 14, 16, 18, 19, and the motor drives the chain 22 of the carriage 9. In another embodiment, the spraying electrodes, driving chains (arranged as in the first described embodiment) motor, paint tank, an air compressor and a high-voltage generator are mounted on a gantry which is movable on rails in a supporting arch structure longitudinally of the article to be sprayed. The gantry is moved in either direction by an electric motor mounted on the gantry. In both embodiments, the electrodes 33 are dish-shaped and connected by flexible leads 34 to a high-tension source, liquid being supplied to the rear face of the electrode 33 through a pipe or hose having suitable valves and terminating in a nozzle, and each electrode 33 being rotated during operation about the longitudinal axis of the arm 32. The supply of the liquid to the electrodes 33 and the movement of the electrodes 33 may be automatically controlled by time or contact switches or by photo-electric devices in the path of the object 39.