Patent GB-870532-A (GB)
Title: Improvements in machine for casting printing plates
IPC: B41D3/00
Filed: 1959-05-11
Abstract: 870,532. Casting stereotype plates. WOOD NEWSPAPER MACHINERY CORPORATION. May 11, 1959 [July 3,1958], No. 16058/59. Class 100(2) A stereotype plate casting machine comprises a casting station, a trimming section and a cooling section arranged along a common longitudinal axis which is at an angle to the horizontal axis of the machine and supporting rollers which support and guide the plates as they move by gravity through the successive sections, the casting station comprising a rotatable and longitudinally movable cylindrical core, a semi-cylindrical casting-box reciprocable in a direction at right angles to the common longitudinal axis towards and away from the core, and a mould cavity formed by the adjacent opposed surfaces of the core and the casting box. Casting station. The hollow, cylindrical core 6 is water-cooled and has a grooved periphery, the grooves 12 being undercut. The casting box is formed by a semi-cylindrical, water-cooled, hollow shell 8. The space between the inner wall of the casting box 8, to which the matrix is secured, and the outer surface of the core 6 is closed at one end by a semi-circular manifold 21 connected to a pipe 24 and having nozzles 20 through which molten metal is discharged into the mould. The contacting surfaces of the manifold, core and casting-box form a joint which is metaltight but not air-tight so that air is allowed to escape from the mould cavity as metal is introduced into it. The other end of the mould cavity is closed by a semi-circular flanged member 25 mounted on the hub of the core 6 and movable axially with respect thereto. The core 6 is secured to one end of a sleeve 10 rotatably and reciprocably mounted on a fixed shaft 11. A gear 13 is keyed to the sleeve 10 and meshes with a toothed segment 14 which is oscillated through a sufficient arc to effect a 180 degree oscillation of the core by means of a crank arm 15 attached to the end of the shaft 16 of an hydraulic motor 17. The gear 13 carries a ring 33 to which is attached a yoke lever 34 to whose lower end is connected a crank arm 35 carried by a crank shaft which is oscillated by an hydraulic motor, the yoke lever 34 being oscillated once for each oscillation of the core 6. A pair of upstanding arms 37 is attached to and moves with the yoke lever 34 and is connected by links 371 with the flanged member 25. As the length of the arms 37 is greater than the length of the corresponding part of the lever 34, when the lever 34 is oscillated the core 6 is moved (to the right in Fig. 2) away from the manifold 21 and the member 25 is moved away from the core 6. The casting- box 8 is carried by a frame 26 which slides in a fixed frame 27. A block 28 attached to an arm 29 depending from the frame 26 is guided so as to prevent tilting of the frame. A counterweight device 100 is connected to the block 28. The frame 26 is raised and lowered by crank arms 30 connected to a' crankshaft 31 which is periodically oscillated by an hydraulic motor 32 through an arc of 180 degrees. When the casting- box is in its raised position molten metal is injected through the nozzles 20 into the mould cavity and allowed to cool by contact with the cooled core 6 and casting-box 8. Molten metal in the pipe 24 is sucked back into the furnace before it cools. The casting box 8 is then lowered, the cast plate being held on the core 6 by the undercut parts of the grooves 12, and the core 6 and member 25 are moved axially to the right as seen in Fig. 2 whereby the portions of metal which have set in the nozzles 20 are withdrawn therefrom and the member 25 is moved clear of the plate. The core 6 is oscillated through 180 degrees so that the plate lies on the upper side thereof and is moved axially, with the member 25, back to its position for casting. The casting-box 8 is raised into casting position again and rollers 7 carried at its upper edges engage the lower edges of the semi-cylindrical plate and lift it clear of the core 6, the parts of the plate which engage in the undercut parts of the grooves 12 being broken away. The rollers 7 are carried by arms 70 pivoted to the box 8 at 71 and having cam followers 72 at their lower ends. As the box 8 is lowered away from the core 6 the followers 72 engage cams 39 so that the rollers 7 are moved outwards to clear the newly cast plate on the underside of the core. As the plate lifted by the rollers 7 is lifted above a stop 61 the plate rolls from the rollers 7 on to corresponding rollers at an intermediate station where it may be arrested by engagement with a stop 56 which can be raised into operative position by means controlled by the operator. Alternatively the plate may roll through the intermediate station on to rollers 43 of an inspection station where it is arrested by a stop 60. Inspection station. The stop 60 is raised and lowered by an hydraulic cylinder 59, being lowered automatically to release a plate which has been inspected as a newly cast plate clears the stop 61 and raised again in time to arrest the latter plate when it reaches the inspection station. If inspection of a plate takes longer than the time allowed by the automatic control the operator raises the stop 56 at the intermediate station to arrest the delivery of plates until the inspection station is clear. A frame 41 at the inspection station is mounted for oscillation on a shaft 42 and carries the rollers 43 on either side. The operator turns a hand crank 45, Fig. 6, to oscillate the frame 41 as he inspects the plate thereon. A pair of ejection arms 62 is loosely mounted on shaft 42 and is connected by means of a linkage toasecondshaft 63 which is driven, through gears 64, from the shaft 42. One of the gears 64 has a lost motion connection with its shaft so that the shaft 63 does not begin to turn until the shaft 42 has rotated through an angle greater than the normal angle of rotation necessary for inspection of the plate. A defective plate is ejected from the machine by the operator's turning the crank 45 far enough to oscillate the frame into the Fig. 6 position wherein one edge of the plate is engaged and lifted off the rollers 43 by the upper end of a shoot leading back to the furnace while the arms 62 are moved to the tops of slots in the frame 41 to lift the other edge of the plate off the corresponding rollers 43 and eject the plate into the shoot. If a plate is not ejected at the inspection station, lowering of the stop 60 allows it to roll down to the trimming and cooling sections which are of known construction. The motors are controlled for sequential operation by a time control system which can be set to repeat the cycle of operations a given number of times. If a plate js ejected at the inspection station the system is automatically adjusted so as to produce an extra plate.