Patent GB-190725057-A (GB)
Title: Improvements in Matrices and in Apparatus for Casting Curved Stereotype Plates therefrom.
Inventor: LOCK WILLIAM HENRY
Filed: 1907-11-12
Granted: 1908-11-12
Abstract: 25,057. Lock, W. H., [Wood, H. A. W.]. Nov. 12. [Cognate Applications Nos. 25,059 and 25,060, A.D. 1907, dated Nov. 12.] Stereotype.-Relates to means for holding the matrix and for stripping it from the cast plate, described as applied to the machine described in Specification No 18,742, A.D. 1897. The plate is cast in a mould formed by a water-cooled cylinder B, shown in Figs. 4 and 5 of the drawings filed with Provisional Specification No. 25,057, A.D. 1907, and a semi-cylindrical shell C raised and lowered by a cam. The ends of the mould are closed by semicircular rings and the metal is delivered into the mould by a spout 24. The matrix f is resilient, and consists of several sheets of backing-paper with four or more sheets of tissue on the face secured together by a paste consisting of red gum, starch, China-clay, flour, and water. The matrix may also be rendered resilient by inserting therein along the curved edges strips of metal or stiff paper. The matrix is provided with two holes which fit over studs 207 fitted with nuts 208 on the bar 206, which engages a dovetail groove in the centre of the shell C. After the plate has been cast, the shell C drops and allows the edges 211, 212 of the matrix to spring clear of the plate P, the centre of the matrix being afterwards detached by the nuts 208. The core B is then rotated through half a revolution, carrying the plate round until it engages stripping-fingers 202, which have been raised by the upward movement of the shell C preparatory to the next cast. A sliding bar then conveys the plate to the trimming- mechanism. In a modified arrangement shown in Fig. 4 of the drawings filed with the cognate Specification No. 25,060, A.D. 1907, the edges of the matrix are stripped from the cast plate by electromagnetic means. The matrix f is secured in the rising and falling shell by studs 207 as described, and is provided along its straight edges with strips 210 of iron or steel. Outside the shell are arranged series of electro-magnets 215 in a circuit containing a contact 220 which is closed by the descent of the shell C. The off side of the mould is in this case closed by a bar 202 on arms operated by links 204 pivoted to the shell C. In a modification, the magnetic material instead of being inserted in the matrix, is in the form of flexible strips which rest in grooves in the end rings of the mould, and bear against the curved edges of the matrix. When magnetic means are employed for stripping the matrix, the shell is preferably made of brass, bronze, &c. In the arrangement shown in Figs. 2, 4, and 8 of the drawings filed with the cognate Specification No. 25,059, A.D. 1907, the matrix M is secured in a holder 21 provided with jaws 23 for holding the matrix along the middle line, and spring arms 24 which bear against the inside of the matrix in the casting position. The holder 21 dovetails into a groove at the centre of the shell and is provided with a handle 22 to facilitate removal. The shell is made in two parts B', B<2>, which are opened and closed by cams 18, 19 and are raised or lowered together by a cam 14 on the shaft 15. After the cast plate has cooled, the shell B', B<2> falls and the two parts separate, allowing the spring arms 24 to strip the matrix from the plate. Fig. 8 shows a modification in which the shell is formed in one piece, and the matrix holder is secured to a bar 29 fitting into a recess in the shell and held therein by studs 30. Nuts 31 on the studs engage stops on the shell during the downward movement of the latter, stripping the centre of the matrix from the cast plate. Rods depending from the ends of the bar 29 slide in the main frame and are furnished with nuts for determining the position of the bar. Springs tending to raise the bar encircle the rods. The ends of the curved arms 24 may be connected by strips 240.