GB787018A - Mechanical movement for coating apparatus - Google Patents

Abstract

A device for moving a spray gun across an irregularly curved surface of a passing object and automatically maintaining the gun substantially normal to and at a uniform distance from the surface, comprises a carriage with rollers guided along two flanges of a supporting beam extending substantially at right angles to, but offset from, the path of the object, the carriage being reciprocated along the beam by an endless chain extending around two sprockets spaced along the beam, the chain carrying a driving member which engages with the carriage and a member movably mounted on the carriage so that it can reciprocate to and from a datum <PICT:0787018/III/1> position, moving substantially at right angles to the supporting beam, and a spray gun carrier pivotally connected to the movable member, the pivoting and reciprocating movement of the spray gun carrier relative to the carriage being controlled by cam surfaces extending in the direction of the supporting beam and related to the reciprocating movement of the carriage along the supporting beam. As shown, a spray nozzle 31 is mounted on a shaft 32 rotatably mounted on a bar 25 and is secured to a link 27 pivoted to the bar 25 and to a link 28 having a cam follower engaging a track 29. The link 28 is pivoted to the link 25 which has a cam follower engaging a cam track 30; the cams are suitably maintained in contact with the tracks by springs. The link 25 is slidable in a carriage 20, a plate 21 of which has rollers 22 engaging the uprights 10 and has rollers 24 engaging the link 25. A lug 36 on a chain 35 passing round sprockets 18 and 38 engaged in a slot 34 in the carriage, whereby as the chain is driven by a motor 12 the carriage is traversed vertically between the sprockets and the nozzle is tilted and moved away from and towards the surface to be coated by the followers engaging the cam tracks. For spraying the top surface a carriage 40 is similarly movable along a horizontal beam 11 which is supported on the beam 10. The nozzle 76 is rotatably mounted on a shaft 51 on a member 64 pivoted on a shaft 63 which is pivoted to a member 62 pivoted on shaft 60 on the carriage 40. A link 59 is pivoted on the shaft 60, and is pivoted to a rod 58 having a follower engaging a track 57. The link 58 is pivoted to a link 55 pivoted to the carriage 40. An upright rod 45 having a follower engaging a cam track 52 is engaged by rollers 44 on the carriage. An hydraulic cylinder 48 is secured to the rod and the plunger is secured to a member mounted on the nozzle support. The carriage has rollers 42 engaging the beam and is traversed by a bolt 72 engaging in a slot in the carriage, the bolt being secured to an endless chain passing round sprockets 15 and 71 and driven by the motor. Sprockets on shafts 60, 63 and 51 are connected by chains whereby the position of the follower on the cam track 57 determines the tilt of the nozzle and the extension of the plunger of the cylinder determines the height of the nozzle. The cylinder may be operated by valves such as 77 operated by a projection 79 on the surface and another valve may control the spray gun. In an alternative form to reduce overhead clearance, the ends of the horizontal cam tracks are level with the beams and the carriage has rollers engaging a vertical bar which supports a lateral horizontal shaft with a sleeve supporting the nozzle. A follower on one end of the sleeve and shaft engages two tracks whereby the nozzle is reciprocated vertically and tilted as it is traversed horizontally. The height of the horizontal beam may be adjustable and the spray gun may be automatically shut off. In a further embodiment and gun which is reciprocated along a beam inclined to the vertical is moved towards and away from the surface and is tilted by a double crank engaging the edges of a shaped aperture. The double crank is pivoted on a shaft carrying a sprocket on one end of a reciprocating bar, the nozzle being mounted on a shaft also carrying a sprocket at the other end of the bar. The sprockets are connected by a chain to effect movement of the nozzle. Articles such as motor car bonnets are carried on an intermittently operated overhead conveyer past the nozzle and are rotated during spraying. Specification 787,019 is referred to.