Patent GB-200794-A (GB)
Title: Improvements in engraving machines
IPC: B44B3/00
Filed: 1923-04-17
Abstract: 200,794. Federated Engineers Development Corporation, (Assignees of McKeown, S. C., and Bruckner, C. C.). July 14, 1922, [Convention date]. Copying mechanism. - Relates to engraving machines of the kind in which a tracer by following parallel lines covers the area of a pattern, the work being simultaneously reciprocated relatively to a cutting-tool which is moved vertically, under electrical control, into and out of contact with the work in accordance with the vertical movements of the tracer, and consists in pivotally mounting the tool carriage whereby movement of the tool transversely to the direction of relative reciprocation may be effected by rocking the carriage about its pivot. Improvements are also described in the arrangement and construction of the mechanical and electrical parts and in the driving-mechanism. General arrangement. The machine comprises a work-holder 7 and pattern-holder 5 fixed on a shaft 13; and a tracer-carriage 4 and tool-carriage 58 fixed and loosely mounted respectively on a parallel shaft 11, these two shafts being moved in one direction by cams 33 and 67 on a driving shaft 3 and in the other operative direction by springs 34 and 66 attached to the pattern-holder 5 and tracer-carriage 4 respectively. The carriages 4 and 57 are fed forward intermittently so as tocover the pattern and work respectively, the cams for operating them being arranged to reduce the lateral scale of the reproduction. The longitudinal scale is also reduced owing to the cams 33 and 67 being angularly spaced and providing a mutual reciprocation of the pattern and tracer. Work and pattern-holders. The work-holder 7 is particularly adapted for receiving articles such as fountain pens, pencils and cigarette holders and consists of a bracket 22, Figs. 1 and 6, provided with overhanging extensions 25 against which thework is held by a V-ended member 31 pivoted at 29 to the bracket and adjusted by a screw 32. The pattern-holder comprises a sleeve 14, Figs. 1 and 5, fixed by screws to the shaft 13 and provided with a recess 16 to receive type &c. and clamped between screw-adjusted plates 18 and centrally fixed by means of screws 19<1>. In order to prevent rotation of the shaft 13, the sleeve 14 is provided with an extension 20 straddling a shaft 35. Tool and tracer-carriages. A cutting-tool 6 is carried by one end of a bell-crank 57 pivoted between brackets 56 mounted on a sleeve 53 on the shaft 11. The tool is raised by electromagnets 60 situated between the brackets and adjacent to an armature 59 on the other end of the crank 57, and falls by gravity assisted by a spring 64 mounted on a post 62 and adjustable in tension by a cam 65. The tracer consists of a diamond 46, Figs. 5 and 7, fixed at an angle of 60 degrees to an arm 42 spring- pressed downwardly and pivoted at 39 within a yoke 38 extending from the carriage 4. When the tracer 46 rides over the pattern contacts 43, 41 are opened thus de-energizing the magnets 60 and lowering the tool. The brackets 56 and the carriage 4 are pivoted with respect to the shaft 11 and are moved angularly step by step, to provide the necessary lateral movement of the tool and tracer, by cams 28 and 48 engaging respectively the brackets 56 and an extension 49 of the carriage 4. These cams are fixed on a shaft 35 rotated by a pawl 73, Fig. 1, on an arm 71 pivoted on the shaft 35 and oscillated by a cam 72 on the driving-shaft 3, a retaining pawl 74 also being provided. For setting purposes a knob 47 is also provided on the shaft 35. To retain the extension 49 in contact with the cam 48 a spring finger 50, Fig. 5, is attached to the carriage 4 and carries a roller 51 riding on a raised track 52. The tool and tracer are raised and supported by lugs 76 and 77 on a shaft 75, the former engaging the tool arm 57 and the latter a crank 78 the end 81 of which engages under the tracer arm 42. For oscillating the shaft 75, a block 83, fixed on its end, is connected by a rod 84 to the arm 71. . Driving and stopping arrangements. The driving-shaft 3 is driven by gearing from a spring motor of conventional type enclosed in one end of a box 1 forming the base of the machine. The drive is through a ratchet wheel so as to allow the shaft 3 to overrun the motor during the spring- impelled stroke. For stopping the machine when the tool has covered the desired area, an adjustable screw 108, Fig. 1, on the tool carriage, is adaptedto release a trip-lever holding a trigger 103 fixed on a shaft 101 provided with an arm 104 controlling- a brake coacting with a disc on the governor shaft of the motor, the arrangement being such that the brake incidentally limits the speed of the motor. A hand-knob 3<1> is also fixed on the shaft 3. Electrical arrangements. One lead from a battery is earthed and the other is connected through the electromagnet 60 to the contact 41 coacting with the contact 43 on the tracer arm 42, Fig. 7. In order to raise the tool 6 at the end of each stroke, the magnet 60 is earthed through a spring contact 127, Fig. 1, which is engaged by cams 126 on the driving-shaft 3. Specification 198,342 is referred to.