Patent GB-1263800-A (GB)
Title: Apparatus for controlling the operation of a spray gun
Inventor: KNIGHT HOWARD RICHARD JAMES
IPC: B05B12/14
Filed: 1969-09-03
Abstract: 1,263,800. Spray producers; coating apparatus. CARRIER ENG. CO. Ltd. 19 Aug., 1970 [3 Sept., 1969], No. 43668/69. Headings B2F and B2L. A control system for a spray apparatus which may be used to coat, e.g. car bodies, valve means 2 including a pluarity of liquid delivery ports, these each connected to a different source of liquid, and purging fluid ports connected to sources of purging fluid, a programme unit 43 and timing unit T operating a selector mechanism to selectively position a feed means to spray guns 32 and 33 opposite the purging fluid or liquid delivery ports. As shown these ports are arranged in a circle, eighteen being connected to different colours of paint (4, 5, 6, and 21) one purging fluid port 23 connected to a compressed air supply line 40 (via line PA and a spool valve 147) and the other conected to a solvent supply line SSH in which is a valve 47. A rack 37 and pinion 26 moves a tubular arm 25 and a valve plate 29 relative to the ports, such that the end 28 of the arm 25 cooperates with one or other of the ports and can receive fluid therefrom to supply via line 31 to the spray guns. The valve plate 29 shuts off all other ports. The rack 37 is moved by a piston in a double acting cylinder actuated by compressed air from lines 48 and 49 from a solenoid valve CV controlled by the timing unit T. A stop block 38 contains nineteen pneumatically operated double-acting piston stops 39, these being operated by compressed air controlled by eighteen solenoid valves, these valves themselves being actuated by the programming unit. Each double-acting piston stop 39 has a cylindrical extention which can be moved in and out of the path of the rack 37 in the block 38, thus the rack can be positioned using these stops (Figs. 3 and 4, not shown). The nineteenth piston stop 39 is connected via a compressed air line ASL and the solenoid valve S under the control of the timing unit T to the compresed air supply 40, this solenoid valve also causing spool valve 47 to operate. In operation the supply of paint to the gun is changed by moving the piston fully into the cylinder 36, this connecting a compressed air supply to the guns through port 37. After a predetermined amount of air has been supplied the solenoid S is actuated to operate the nineteenth piston valve and open valve 47, supplying solvent to port 22, which supply is connected to the guns after the rack has been moved to engage the stop in the stop block. This process is reversed after the guns have been cleaned, the compressed air and then the paint of a chosen colour (depending on which piston valve 39 in the stop block 38 is operated) being supplied to the guns. The guns are also supplied with atomisation air, this being under the control of a spool valve 55, which valve is controlled by timing unit T via solenoid valve CV. The timing unit T in conjunction with the programming unit 43 controls the entire spraying operation through solenoid valves CS, S, CV, A and C. The apparatus may be used for painting automobile bodies.