Patent GB-319027-A (GB)
Title: Improved machine for producing or reproducing designs, letterpress, numerals and other forms, and for the manufacture, if desired, of corresponding records for subsequent reproduction
IPC: B44B3/00
Filed: 1928-03-14
Abstract: 319,027. Wilkins, W., Vandy, E. J., Vandy, G. E., and Vandy, W. March 14, 1928. Printing - surfaces; engraving. - In a machine for drawing or copying designs on lithographic stones or other surfaces, or for engraving, or other purpose, the movement of the operating tool, such as a pen Z, Fig. 1, is obtained from two driving forces acting to produce motions in directions inclined to one another, the driving forces being each obtained from an uninterrupted drive which imparts a relative movement to the operating tool the direction of which is determined by relatively adjusting the forces by means of a perforated band or other record of predetermined form. The machine is a development of the machine set out in Specification 166,252. The method of operating the machine is illustrated in the diagrammatic view shown in Fig. 1, in which a drawing - pen Z is mounted in a carriage O which is anchored to wires P passing over pulleys Q, R mounted on a bridge member B. The bridge B can be moved in a direction at an angle to the carriage bv means of wires E anchored to it and driven by pulleys K on a shaft L driven from a shaft r. The pulley R is driven from a shaft T connected bv worm gearing U to a shaft V geared to a shaft q. The shafts r, q are driven from a common motor g through two similar trains of epicyclic gears which operate differential gears 79, 80, 81, 82. The output gears 82 of the differentials are geared to the shaft r, q and by varying the motion given to the shafts r, q, the direction of the instrument Z is controlled. The epicyclic trains are controlled by a series of pawls v<1> - - v<6> and w<1> - - w<6> controlled by cams u<1> - - u<6> on a cam shaft u which is intermittently rotated by ratchet mechanism controlled by a pawl x operated by electromagnets energized by current controlled from an electrical contact z actuated by a perforated band l. A part of one of the epicyclic trains is shown in Fig. 4, and comprises a series of ratchet gear wheels 72 freely mounted on a shaft 71 and provided with sunwheels 74, 75 in gear with planet gears 76, 77. Each ratchet wheel 72 has a second ratchet wheel 78 close beside it which is keyed on the shaft 71, and detents pivoted on the wheels 72 engage with the ratchet teeth 78. The pawls v<1>, w<1>, Fig. 7, engage the ratchets 72, and the cams u<1> control the engagement of the pawls with the ratchets. The final motion given to the shafts r, q is dependent upon which wheels 72 are engaged by the check pawls v<1>, w'. As shown, in Fig. 9, the cam shaft u can be moved axially so as to set it in one of three positions by operating a shaft 150 by means of a hand lever 154, the pawls v', w' being put out of operation by an unlocking lever 157. The cam shaft u is operated by escapement mechanism under the control of the electromagnets 135, 136, 138, and 139. The escapement mechanism acts through differential gears 121 - - 124, the output shaft 121 of which drives the cam shaft u either directly by means of prongs 141, Fig. 9, or by means of gears 140, 143, 144 and 142. The electrical circuit for controlling the current to the magnets 135, 136, 138 and 139 is shown in Fig. 9, and comprises a selective switch 169 operated electromagnetically by currents controlled by one feeler 184 co-operating with the band l, and a second feeler 182 controls the currents to the magnets after the selective switch has been operated. Each escapement lever is under the control of two magnets which are energized alternately, and the direction of rotation of the cam shaft is dependent on which escapement lever is operated. To vary the size of the letters &c. drawn by the pen O changespeed gears are arranged between the output gears 82 of the differentials and the driving shafts of the carriage O and bridge B. The gears 82 act through change-speed gears which are controlled by levers operated by shafts fitted with handlevers, and, in order to allow of small changes in the gear ratios, the drive also passes through a cone gear 221, Fig. 6, engaged by a tumble gear 222 which can be adjusted longitudinally by a bracket 224 operated by a handle 228a guided by a helical slot 230 in a convex cover 234. The gear is locked in adjusted position by a locking lever 231. The direction of motion of the pen can be reversed, when desired, by clutches operated electromagnetically by magnets controlled by switches similar to those shown in Fig. 12. These switches are controlled by-reversing cams 201a,201b, 201c, 201d, Fig. 20 which are rotated by gearing from the cam shaft u. The cam shaft u is also geared to a pointer 215, Fig. 20, which gives a visible indication of the direction in which the pen is, travelling. The axial adjustment of the cam shaft brings into action cams which, when the cam shaft is rotated in a regular step-bystem manner, control the pen so that the letter O is drawn as a regular polygon of a number of sides varying according to the particular cam in operation, thus permitting a small letter to be drawn at a greater speed. Other variations of gears may be employed before the final output shaft is reached. For example, differential gears may be employed which normally transmit motion to either the carriage or the bridge only. In order to produce slopes in capital letters these differentials may be controlled so as to transfer part of the motion from the bridge to the carriage or vice versa when normally only one of the members would be moving. Other variations of gears may be arranged so as to reverse letters, or to cause a design to be spread out laterally, or raised in height, by causing one of the complementary motions to have a greater speed than the other. The drawing pen or marker is mounted so that it can rotate in a cylindrical casing 390, Fig. 28, under control of a pair of electromagnetically reciprocated pawls, which engage ratchets 394 on the pen fountain for rotating the pen on its axis in either direction while curves are being drawn. The pen is automatically raised by a lever 416 actuated by an electromagnet 415, and a valve 429, Fig. 36, automatically cuts off the supply of ink as the pen is raised; or the feed is by capillary action dependent on contact with the work. The blade of the pen may be broad and be set automatically to the axis of the fountain, and in some cases the blade is pivoted about a horizontal axis. The pen movements are controlled by the record. The work is placed on a'table A, Fig. 2, which can be adjusted vertically by screws 438 operated by gearing 439 from a hand-wheel 440. The driving-gears are mounted at the side of the table A and are indicated diagrammatically at X, X<3>, X<4>, which represent respectively the epicyclic gears, the change-speed gears, and the final differential gears. Two record bands are driven by change-speed gear 382, Fig. 51, from the shaft which drives the epicyclic -assembly, and this gear permits variations to be made in the rise of the design produced. The table A may also be raised or lowered by mechanism similar to that which gives the tool 2 its two components of motion, or the tool 2 may be given this third component, so that carvings or other work involving three dimensions may be produced by the machine. To change over from one record band to another, a lever 644 is operated so as to cause a catch 652 on it to engage one or other of two notches 645, 647, or a central notch 646 if no band is required to be driven. The lever 644 moves a sliding rod 657 against the action of a spring 658, and gears 662, or 663 are brought into operative engagement with gears 664, pressed axially by springs, according to the direction in which the lever 644 is moved. When the lever 644 is in neutral position the electrical circuits of both record frames are broken. The feeler members for controlling the operation of the machine are mounted in a cage 583, Figs. 2 and 48, supported by the record frame, and capable of being moved laterally in order to set the feelers to reproduce the desired letter, by the aid of a marked scale and a pointer on the cage. The cage can be pivoted away from the band by a lever 603 and link 601 when the record is to be rewound, the driving-roller 586<a>, Fig. 48, being at the same time tripped. The record band passes from a spool 584 over roller 585, under cage 583, between rollers 586, 586a, and over a take-up spool 587. The take-up spool is preferably drawn at constant speed by friction gear in such a manner as to compensate for the increasing diameter of the roll. For rewidening the roll, a lever 617 is operated to bring friction discs 615, 616 into operation. The lever 617 can be held in operative position by a catch only when the roll needs rewinding. A friction pawl 630 prevents manual rewinding of the roll when the cage is in operative position. To assist in determining the particular gears required to produce letters of a given size a calculating apparatus is employed consisting of a cylinder to which is attached a chart marked off with concentric circles, one representing each change gear, and being graduated in unit lengths. Readings from the circles are taken against a fixed reading edge bearing the gear numbers which are arranged against their respective circles. The cylinder bearing the chart is geared to a movable pointer which is moved over a series of lines representing the total amount of movement of the record band to produce a given letter and the necessary spacings. The various operations of the machine for printing a given letter or design may be controlled by a single line of perforations in the band, and these first operate a selector switch Fig. 54, consisting of a light drum 674 which is rotated step-by-step by a ratchet 677 and a pawl 684 operated by an electromagnet 678. A series of inclined pegs 675 on the drum successively close contacts 676 in the circuit to be controlled, but the circuits containing th