Patent GB-191204672-A (GB)
Title: Machine for Making Stereotype Printing Plates.
Inventor: HOPKINS CHARLES EDWARD
IPC: B41D3/00
Filed: 1912-02-24
Granted: 1913-02-24
Abstract: 4672. Hopkins, C. E. Feb. 25, 1911, [Convention date]. Stereotype; printing-surfaces.-Relates to apparatus for casting, trimming, and cooling curved stereotype plates in which the plate is cast between a vertical shell and a movable core which can tilt to remove the plate from the mould and deliver it on to an inclined track, down which it slides to the trimming and cooling apparatus. The contraction of the plates during cooling, is controlled so that plates of different curvature may be produced from the same mould. The mould comprises a water-jacketed concave shell B secured to a frame C, and a water-jacketed convex core D movable on rollers running on tracks 80 into and out of the mould to the position shown in Fig. 1. The matrix is clamped in the shell B by clamps, Fig. 12, supported on shafts 44 turning in bearings 45 at the sides of the shell. The clamps comprise bars 50 pivoted by lugs 52 on the shafts 44, and pivoted clamp bars 56 which grip the matrix against straight edges. The clamping - bars 56 have located beneath them spring plungers 58 tending to rock them outward against the bevel 49 on slides 48 connected to arms 46 on the shafts 44. In the jaw at one side of the shell are located a series of spring plungers 61 which engage the matrix to force it well into the shell before making a cast. The shafts 44 supporting the matrix clamps are opened by the movement of the core D out of the back B, and are closed by the actuation of a pedal 146. A second pedal 149 is provided for opening the clamps without moving the core. The bottom of the mould is closed by a ring supported on the shaft 72 which carries a spring tending to turn the ring out of the mould. The ring is turned into the mould by the lower end of the core D for which it forms a seating. The core D is supported on rollers running on tracks 80 very near its centre of gravity, so that without a plate thereon, the core has a tendency to tilt into the back; but with a plate having the heavy head or riser intact, it tends to turn into the position shown in Fig. 1 to deliver the plate. The core is formed with a slotted bracket which works over a roller on the shaft 114 and operates to turn the core into and out of position in the mould. The bracket carries a roller which engages in a face cam on the shaft 114 which is turned to moved the core by a handle 115. The rollers supporting the core are mounted on a shaft carried by a slotted lever working over a roller in the frame C. Sliding on the edges of the core are lifter bars 95 which, when the core assumes the position shown, engage cams 126 on the shaft 114 and are thereby raised to lift the cast plate from the core. When the core is in the casting position, these plates fit against the faces 62 of the matrix clamps and form the edges of the mould. The matrix is held at the top during the cast by a ring 97 which is hinged to one of the plate lifter-bars. When opened as shown, a hook thereon interlocks with a lug on the frame and prevents premature movement of the core. A spring catch holds the ring in position on the core. The core is also prevented from being turned into the casting position, when the matrix clamps are open, by a spring catch. The cast plate slides from the core into a trimming arch E where the internal ribs are shaved and the leading curved edge bevelled. The plate runs into the arch on a series of rollers until it is arrested by the engagement of lugs P<2>, cast on the concave side of the head, with two stops 160, 161, the latter of which is spring-supported to allow of a slight sideway movement. The first supporting-rollers are carried on the inside of the trimming- arch, and beyond the arch for supporting the head are three additional rollers on a frame carried by the central shaft 158 which is driven by a one-revolution clutch. As soon as the main shaft commences to revolve, these rollers are drawn inward by a slotted plate moved axially by a stationary cam. At the same time a cam thereon operates a clamp sliding in an inclined groove to move the plate up into the crown of the arch and hold it while the internal ribs are shaved by a knife secured adjustably to the main shaft. The mechanism for separating the head comprises a casing 201, fixed to the main shaft, in which is mounted a shaft 203 having at one end a cutter 200 and at the other a pinion 204 driven by a wheel 205 from a wheel 209 loose on the main shaft 158 and driven by chain gear 212 from the shaft 252. As the casing turns around the plate, the head is detached and is supported in a saddle 220 on the main shaft 158. As the rotation continues, the head slides over and is held by teeth 217 on a hinged flap 215 of the casing 201, which finally opens and projects the head clear of the machine. The shaft 158 is driven by worm gearing 225, 226 with a safety shearing- pin, and a one-revolution clutch controlled by a pedal 259. The plate, after trimming, slides by gravity on to rollers 280 on a pivoted cooler F, Fig 26, which is normally held at the same inclination as the trimming-mechanism by an arm 287 and a spring 286. The cooler is held thus by a catch 289, which is disengaged by the edge of the advancing plate, the weight of which turns the cooler on its pivot 275 into an horizontal position. A pin 296 on a lever 292 engages a latch 295 on a valve-rod 294 and opens a valve 278, allowing the cooling-water to flow through a flexible pipe 276 to the crown of the cooling - saddle 271 which is made of flexible sheet metal secured to brackets 281. A head 308 on the lever 292 engages a pin 307 on n, disk 300, moving the disk so that its periphery comes into contact with an extension 304 on the shaft 231. The disk is thereby driven by friction for a complete revolution, a pin 310 meanwhile disengaging the latch 295 from the pin 296 and cutting off the water supply. As the water is supplied to the concave face, the plate has a tendency to contract, but, as the cooling proceeds through the plate, it tends to open out again. By restraining either of these movements plates of different curvature may be produced. For this purpose each bracket 281 attached to the cooling-saddle is formed with a rib 282 which engages the edge of the plate, and on the underside with a recess 284 and a projection 319 for engaging an adjustable stop 317. The stop 317 can be moved outwards against the projection 319 to prevent the initial contraction of the plate, or to produce plates of larger diameter, or so that, after a slight contraction, the stop engages in the recess 284 to prevent the subsequent expansion and form plates of lesser diameter. After cooling, the plate is removed manually, the plate being then just sufficiently warm to evaporate the remaining water. The cooling-water may be applied to the external face of the plate.