GB448986A - Improvements in or relating to the coating of hollow bodies - Google Patents

Abstract

A machine for coating a portion of the interior surface of a hollow body comprises means for depositing a coating material on a portion of the inner surface of said hollow body and means, operating alternately with said depositing means, for removing excess coating along an edge of said coated portion. The machine illustrated, for use in coating the interior of electric lamp bulbs, comprises a rotary conveyer 10, carrying bulb holders 12, which is moved intermittently and passes through an oven 14. A bulb 16 is placed <PICT:0448986/III/1> <PICT:0448986/III/2> <PICT:0448986/III/3> <PICT:0448986/III/4> <PICT:0448986/III/5> p in a holder at A and moves first through the oven where it is heated to about 350 DEG C. At B, a spray gun 17 enters the bulb and sprays a coating material on to the bowl portion thereof. At D, compressed air is directed into the bulb to remove any loose particles of coating material, and at E and E<1>, wipers 20, 20<1> move into the bulb and are rotated at high speed to remove irregularities along the margin of the coating, giving a sharply defined border. The bulb is removed at F. At B, the bulb is lifted from the holder 12 and is gripped between rotatable and adjustable holders 18<1> and 25, the latter being driven so as to rotate the bulb, and the spray gun being moved into position with its nozzle 40 within the bulb. The gun is mounted, for movement into and out of the bulb, on a reciprocated carriage 55, and, when in operative position, is oscillated, through a predetermined arc, about the curved surface 54 by the sliding movement of a plate 44. A member 58 contacts with a valve-controlling lever 59 to cause the coating material to be discharged only while the nozzle is in its operative position, and when the nozzle is withdrawn the bulb is freed and again rests upon the holder 12. Each wiper consists of flexible radial strips 65, e.g. of chamois leather, carried by a rapidly rotatable shaft 66, and these shafts are moved into and out of a bulb by arms 110, 111, operated by a rack 102 reciprocated by a driven cam 94, a rocker arm 96 and a bellcrank lever 99. The bulb holder 12 comprises adjustable V-shaped supports 109<1> and 110<1>, and, during wiping, the bulb may be held down upon these supports by a spring-pressed finger 118 on a rocker arm 119. When the rack 102 is moved forward to withdrawn the wiper members from the bulb, the roller 122 enters a notch 123 in the arm 119, thus allowing the finger 118 to lift and release the bulb. Specification 302,170, [Class 95], is referred to.