Patent GB-198342-A (GB)
Title: Improvements in engraving machines
IPC: B44B3/00
Filed: 1923-03-28
Abstract: 198,342. Federated Engineers' Development Corporation, (Assignees of Bruckner, C. C.). May 26, 1922, [Convention date]. Copying mechanism.- Relates to engraving machines of the type in which the work is reciprocated beneath a tool movable into and out of engagement therewith, the movement being controlled electrically from a switch or the like which is opened or closed by the engagement of a stylus with a pattern over which the stylus is traversed in co-ordination with the work. and consists in pivotally mounting the stylus so that it oscillates in a plane parallel to the path of relative reciprocation between the stylus and the pattern. Detail improvements in this type of machine are also described including devices for centring the work and pattern with respect to the tool and stylus, for inclining the reproduction and for stopping the machine when the engraving is finished. The work is fixed in a chuck 29, Figs. 1 and 4, removably mounted on a table 3 slidable in guides 18 in a carriage 13 and reciprocated by a motor 2 through a worm. on the motor-shaft, a worm-wheel 20, change-speed gear comprising a friction roller 22 and disc 23, and a rod 26 connected to the carriage and to a block 25 adjustably secured in a diametrical slot 24 in the disc. For holding irregular work the chuck may be pivoted at one side and adjusted by a screw 34, Fig. 4, at the other. A cutting tool 8 is horizontally adjustable with respect to a post 7 carried by a base 6 and vertically adjustable with respect thereto by means of a rack 10 and pinion 9. The base 6 is slidable on rods 5 and adjustable by means of a hand-operated screw 11. The pattern, shown as consisting of types, is clamped on a table 4 slidable on fixed rods 50. A stylus 67, situated over the pattern table 4 and preferably bent over to one side to ensure smooth working, is carried by a support 70 slidable on a rod 68 extending from the table 3 and operated in conjunction with the latter by means of an arm 75 fixed to the table and pivoted to a rod 76 pivoted at one end to the support 70 carrying a block 79 on which is a crank pin slidable in a slot 78. The carriage 13 is mounted on the rods 5 and is moved step-by-step along them to advance the work and stylus by means of a screw 14 operated by a pawl 37, Fig. 4, carried by a spring-controlled bell-crank 38 connected to a rod 39 normally held depressed by a solenoid 40 and released prior to each cutting stroke. The feed of the screw 14 is regulated by stop-pins on the rod 39 in conjunction with an abutment 44. The tool 8 is carried by a bell-crank 92, Fig. 3, normally spring-pressed against a screw 97 adjustable to regulate the cutting depth but adapted to be raised by a solenoid 81 controlled from the stylus 67. The latter is mounted on a shaft 72, Fig. 6, which is thereby oscillated as the stylus moves over the types and hence closes contacts 82, 84 and 83, 85, Fig. 13, alternately, one pair corresponding to a reproduction in relief and the other in intaglio, the pair in use being determined by a switch 86. The electrical connections are shown in Fig. 13, a cam mounted on disc 23 being adapted to close spring contacts 41 after each working stroke, thus energizing the magnet 40 for operating the screw 14. A magnet 74 co-operates with an armature 73, Fig. 6, on the stylus 67 to raise the stylus clear of the type on the return stroke, the magnet 81 being also energized to ensure the tool 8 being raised. The dimensions of the reproduction may be varied by adjusting the block 79 along the rod 76, and by altering the pivotal point 54 of a bar 53 connected to the table 4 and to a pivoted lever 51 connected by a bar 52 to the carriage 13. The consequent movement of the table 4 adds to or subtracts an adjustable amount from the effective movement of stylus according to which side of the point 54' the pin 54 is situated. To incline the reproduction the rod 39, Fig. 4, is adapted to actuate by means of pawls 113 either of two rachet wheels 110, 111 fixed to a screw 30 whereby the chuck 29 may be adjusted either forwardly or backwardly in the direction of its reciprocation. In use the work is centred with respect to the tool 8 by manual adjustment of the screw 14 when the disc 23 is in mid-position, indicating hands 17<a> and 23<a> being provided for this purpose. The tool and chuck may also be adjusted if necessary. The shaft 14 is then rotated until the stylus is at the extreme edge of the pattern when the machine may be started. The motor switch is actuated to stop the machine when engraving is completed by a circuit including contacts 105, Figs. 12., 13, on a sleeve 102 slidable on one of the rods 5 and mounted on one end of. a bar 100 pivoted to an extension 101 of the slide 6. A similar sliding sleeve 103 on the other end of the bar and on the other rod 5 is carried forward by the carriage 13 in its final adjustment whereby the sleeve 102 is carried rearwardly an equal distance so that when the carriage has traversed to the required extent the contacts are closed. The types are clamped on the table 4 between a fixed jaw 55, Fig. 11, and a pivoted jaw 56 tightened by rotating the eccentric pivot 58 of a hook 57. The pattern is centred by clamping blocks 61 adjusted by a right and left hand screw 60. For providing a border when reproducing in relief, straight border pieces 65, 65<1> and shaped end pieces 66. 66<a> of the same height as the sunken surface of the pattern may be fixed as shown. The Specification as open to inspection under Sect. 91 (3) (a) comprises also (1) an attachment for engraving the inner and outer surfaces of rings consisting of an arm 126, Fig. 15, (Cancelled), attached to the carriage 13 and carrying a bearing for a chuck 123 rotatable by a pinion 124 on the chuck and a rack 125 on the carriage, and (2) a rotary tool clamped on the lower end of the spindle of a motor, the upper end being raised by the electromagnet 81. This subject-matter does not appear in the Specification as accepted.