Patent GB-446024-A (GB)
Title: A method of and means for the manufacture of covering glasses, particularly watch glasses made of celluloid or similar material, with outwardly cambered or curved surface
IPC: G04D3/06
Filed: 1934-11-16
Abstract: 446,024. Cutting-out celluloid and the like. POLLAK, R., 10, Gumpendorferstrasse, Vienna. Nov. 16, 1934, No. 33036. Convention date, Nov. 16, 1933. [Class 31 (i)] [See also Group XVI] A method of making watch and like dial coverings of celluloid and like material consists in forming a frame or matrix, the size and outline of the opening therein being cut to the size and outline of the opening to be covered, placing over the frame a sheet of celluloid or like material, pressing the sheet into the opening in the frame to form the desired camber or curve, and finally cutting the curved or cambered portion from the sheet. The opening in the frame is cut out in a copying- machine comprising a chuck 4 for the watch or like article or its frame, and a carrier 18 for the frame or matrix to be cut, mounted at each end of an axle 3. The chuck 3 consists of two jaws 5, 6 slidably mounted in guides on a fixed disc 9, and adapted to be moved radially in the guides by a spring-controlled rotatable disc 12 provided with eccentric curved slots. The carrier 18 comprises a work-carrier 24 having at the corners of a square four pins on which large frames to be cut are moimted, and a smaller and removable work-carrier 34 provided with four pins is secured by screws 35, 36 inside the large work-carrier 24. The carrier 24 is adapted, where necessary, to rotate independently of the carrier 18. The copying-arm 39 of the machine is provided with a copying- stud 37 consisting of a piece of wire having a head 50 of conical shape adjustable towards or away from a seating in the end of a sleeve 52. The cutting arm 40 is provided with a cutter 38 adapted to follow the movement of the copying-stud 37. Both arms 39, 40 are spring-pressed towards each other, and are mounted on a rotary axle 41 supported in bearings 44, 45 which can move about an axle 47 secured to the baseplate 1 of the machine. The frame or matrix may be a sheet of celluloid provided with notches which, if the sheet is small, are engaged on the pins of the carrier 34, or, in the case of a larger sheet as shown in Fig. 9, the carrier 34 is removed, and notches 25<1>-28<1> or 25<11>- 28<11> are engaged on the pins of the larger carrier 24. The notches 25<1>-28<1> are shallow, and when the sheet is placed on the carrier 24 using these notches it is bowed or curved to a form suitable for curved watch coverings ; where a flat or plane covering is required, the deeper notches 25<11>-28<11> are used. The watch cover casing is placed on the chuck 4 and the opening traced by the copying-stud 37, and the cutter 38 cuts out a similar opening in the matrix frame. The matrix frame is then inserted on registration pins spaced similarly to those on the work carrier and situated in the recessed lower part of a small hand-operated press, a further celluloid sheet in the hot or cold state and of the same shape as the matrix is superposed over the latter, a block of elastic material is placed over the two sheets, and pressure is exerted on this block. The solid top sheet is dished or cambered by being pressed into contact with the matrix, and is then removed, placed on the pins on the work carrier of the copying- machine, and the finished watch covering cut therefrom by tracing the outline of the opening in the watch casing as before. The adjustment of the copying-stud allows the cutter to cut a slightly larger opening in a matrix or a slightly larger covering from a sheet.