Patent GB-1277235-A (GB)
Title: Screen printing machine
IPC: B41F15/08
Filed: 1969-06-11
Abstract: 1277235 Stencil printing machines W KAMMAN [trading as WERNER KAMMAN] 11 June 1969 [11 June 1968 (2) 29 June 1968] 29492/69 Heading B6C A screen printing machine for the printing of bodies with cylindrical or conical surfaces comprises rotating discs 18, 19, Fig. 3, with devices 21, 22 for receiving and supporting bodies 11 to be printed, conveying the bodies to a position below a reciprocating screen 24 where they are circumferentially adjusted before printing, and discharging the printed bodies, the devices 21 having low friction surfaces engaging the bodies or are themselves mounted on low friction surfaces. An endless belt conveyer (13, Fig. 1) below the discs 18, 19 carries the bodies 11 to and from the discs 18, 19. The discs 18, 19 are carried by a shaft 14 driven intermittently from a shaft 26 through a gear-box 16 at one end, and the shaft 14 and gear-box are supported by a frame 17 pivoted about the shaft 26. By means of an adjusting mechanism 27 ... 32, the frame 17 can be pivoted about the shaft 26 so as to bring the surface of the body contacting the stencil parallel to the stencil. The disc 19 is adjustable axially of the shaft 14 and the devices 22 carried thereby are spring-urged towards the other disc 18. Movement of the devices 22 towards and away from the cooperating devices 21 for receiving, holding, and discharging the bodies 11 is effected by the engagement of a roller 35 on each device 22 with a cam 34 carried by a member 33 movable axially with the disc 19 but rotatable on the shaft 14, the member 33 being oscillated from the driving shaft 58 through means comprising a toothed sector 36 carried by the member 33 and engaging an elongated pinion 37 engaged by a toothed sector connected to an eccentric 39 driven by a cardan shaft 40 geared to the shaft 58. The bodies 11 are positively rotated, as described below, whilst in contact with the stencil. Article supports.-The devices 21, Fig. 5, on the disc 18, for supporting one end of each body to be printed, are formed of a material having a low coefficient of friction, e.g. a plastic such as polytetrafluoroethylene or a sintered metal, and have a recess 43 on which the end of the body slides as the body rotates during printing. In a modification (Figs. 5a, 5b) a ring-shaped member receiving the end of a body is itself rotatable in a bearing surface of low-friction material. Setting the position of the printing on the body surface.-When a body to be printed reaches a position spaced circumferentially from the printing position by the distance between two pairs of supporting devices 20, 21 it is engaged by a device which is projected through the centre of a supporting device 21 and which rotates the body so that the part of its surface required to be printed is approximately correctly positioned. This device comprises a spring-mounted driver 50, Fig. 6, which is rotated and moved axially through an opening in the supporting device 21 at the requisite time and " scans " the end of the body until it engages a recess in the end so as to set an initial circumferential position of the body 11. A similar device is provided at the printing position, but in this ease the shaft 51 carrying the driver has a gear 53 engaging a rack 52 attached to a carriage 23 carrying the stencil, so that the body is positively rotated in unison with the stencil movement during printing. Reciprocation of the stencil carriage 23 is, in one form, effected from an eccentric pin 83, Fig. 11, on a driven disc 82. The pin 83 is connected by a rod 84 to a trunnion carrying a gear 87 mounted on a part 90 of the carriage 23 slidable on guides 80 and engaging a fixed rack 88. The gear 87 engages a rack 89 attached to another part 91 of the carriage 23 also sliding on the guides so that the movement of part 91 is twice that of the part 90. The stencil 24 is fixed to the part 91. In a modified form, the pin 83 slides in a grooved transverse member fixed to the part 90. The disc 82 is driven from the machine drive through a gear 97, Fig. 12, bevel gears 101, 96 and a hollow shaft 98 fixed to the gear 96 and the disc 82. To adjust the stroke of the stencil carriage 23, the pin 83 is threaded and carried by a threaded rod 107 mounted on the disc 82. The rod 107 is connected by bevel gears 111, 113, a shaft 112 and bevel gears 114, 115 to a shaft 116 surrounding the shaft 100 carrying gears 97, 101. Rotation of the shaft 116 causes rotation of the rod 107 and radial movement of the pin 83 to adjust the stroke. Axial movement of a shaft 121 by a handwheel 122 brings a gear 123 on the shaft into mesh with a gear 117 on the shaft 116, so that by subsequent rotation of the handwheel adjustment of the stroke can be effected. Teeth on a member 119 fixed to the shaft 121 engage teeth 118 on the gear 117 to lock the parts in adjusted position.