Patent GB-886221-A (GB)
Title: Improvements in or relating to work-centring devices
Inventor: JAMES DAVID RICHARD
IPC: B41F17/00
Filed: 1956-10-19
Abstract: 886,221. Printing processes. MURRAY CURVEX PRINTING Ltd. Jan. 20, 1958 [Oct. 19, 1956; Sept. 6, 1957], Nos. 31830/56 and 1799/58. Divided out of 28144/57. Class 100(2) A work-centring device comprises a baseplate 13 carrying three or more arms 18 each pivotally mounted for swinging movement in a plane parallel to the base-plate, the arms being arranged so that their free ends can be brought to bear on the work at points angularly spaced with respect to the desired point 24 about which the work is to be centred, an operating element 34 movement of which causes swinging movement of the arms 18 to bring their free ends inwardly towards the point 24, means which separately connect each arm to the operating element to cause the swinging movement of the arms upon movement of the element, and means enabling the independent angular adjustment of each arm about its pivot relatively to the point 24. The device is particularly for use in centring articles of ceramic ware to be decorated as described in Specifications 736,312 and 827,954. The base-plate 13 is adjustably mounted on a sub-frame 12 and is provided with bores 14, the lower ends of which are enlarged and closed by discs 16 each carrying a pivot post 17. On each post 17 an arm 18 is mounted for swinging movement about the axis of the post, each arm comprising a roller or spool 19, 20, 21, 22 respectively, rotatably mounted on the post 17, a portion 23 lying parallel to the base plate and an upstanding portion 25 with a bobbin 26 thereon. The portion 25 may be slightly inclined away from the vertical, towards the work to be centred. The work is engaged by the bobbin 26. Four slits 27, 27a are provided in the underside of the base-plate 13 in which slide tension rods 28, 29, 30, 31 for swinging the arms 18. Rods 28, 29 are connected to short chains 32 on rollers 19, 20 and rods 30, 31 are connected to chains 33 on rollers 21, 22. The outer ends of the rods pass through holes 35 in an operating handle 36 comprising a bar 37 which abuts a lug 34 and is mounted on a slidable guide bar 38 carried in the lug. Thus, when the handle 36 is pulled outwardly the arms swing inwards towards the point 24. The arms are spring biased to their outward position by springs 40, 41. Each rod is provided with a nut 39 so that the arms may be individually adjusted. The handle may be operated by manual, pneumatic, hydraulic or mechanical means. For decorating ceramic ware the centring device is carried by a sliding work-table movable from a position in which the work is placed thereon to a position in which the work is decorated. A centring operation may take place in both positions. In the first mentioned position the centring device is adjacent a magnetic device 11 having a permanent- or electric-magnet 47 mounted thereon for limited sliding movement. When the work has been placed on the centring device the magnet is in contact with a magnetic yoke 44 on the handle 36. As the table moves away from the device 11 to its second position the handle 36 remains in contact with the magnet 47 and is thus pulled outwardly relative to the . base-plate 13 and effects movement of the arms to centre the work. Further movement of the table frees the handle from the magnet and the arms are returned to their initial position by the springs 40, 41. At the second position of the table the arms 18 are swung by a roller 61 on an arm 56 which engages a slot 62 in the bar 38 and pushes the bar 38, and hence the handle 36, outwardly. The arm 56 is keyed to the upper end of a shaft 57 which passes through the work-table. A lever 66, secured to the lower end of shaft 57, is adapted to be acted upon by the piston 63a of a pneumatically or hydraulically operated cylinder 64 which may be controlled by a valve actuated automatically by sliding movement of the work-table. A valve is provided for releasing the build-up of pressure after the arms 18 have reached the limit of their inward movement.