Patent GB-756978-A (GB)
Title: Improvements in and relating to devices for effecting controlled variations of geometrical forms and other shapes
Inventor: DWYER JAMES HENRY
IPC: B23Q35/10
Filed: 1954-03-02
Abstract: 756,978. Pantographic apparatus. PRECISION GRINDING, Ltd. March 2, 1954, No. 6104/54. Class 97 (3). A copying device capable of effecting controlled variations of geometrical forms and other shapes comprises a base to which an image or matrix to be reproduced is secured, a first carriage slidable relative to the base, a second carriage slidable on the first carriage at right angles to the sliding axis thereof and arranged to carry a stylus, a pair of top carriages each arranged to carry a reproducing tool and coupled together for sliding movement in opposite directions at right angles to the sliding axis of the second carriage, and guide means pivotally connectable to one of the pair of top carriages and pivotally linked with the second carriage for transmitting sliding movement of the said second carriage to one of the top carriages. An image or matrix to be reproduced may be secured to a base 1, Figs. 2 and 4, on which a support platform 11 may slide longitudinally, being lockable by clamps 1<SP>11</SP>. A carriage 2 is mounted to slide on platform 1<SP>1</SP> parallel to the base, and carries a second carriage 3 slidable thereon perpendicular to the base. Top carriages 4 and 11 are mounted on carriage 3 to slide parallel to the base, and are interconnected by a flexible steel tape so as to move by equal amounts in opposite directions. A flat bar 7A is mounted for movement perpendicular to the base between rollers 14 mounted on an extension 1A of platform 1<SP>1</SP>, and a bar 7 mounted at right angles to the bar 7A engages rollers 15 carried by an extension 3A of carriage 3. A pivot pin 16 is fixed to the bars 7 and 7A and carries a rotatable bush 23 having two parallel flat side surfaces which bear against the sides 24a of a slot formed in a link 24 which is arranged to pivot freely about a pin 25 by which it is connected to the extension 3A of the carriage 3, when the latter is moved in the longitudinal direction of the base. A lever comprising a pair of connected parallel bars 6 is attachable at one end 61 to the link 24 by means of screws 6<SP>11</SP>. A slider 27 is slidably mounted on the bars 6 and has a central opening which may be fitted over a boss or pivot 17 which is slidable along a bar 26 mounted on the top carriage 4 perpendicular to the base. The boss 17 may be locked to the bar 26 by a clamping screw. The upper face of the bar 26 is engraved with scales E, F, G, H by means of which the boss 17 may be adjusted. A flat bar 5 pivoted at 5<SP>1</SP> to carriage 2 can be set to any desired angle and clamped by a scale bearing plate 5<SP>11</SP>. Bar 5 carries slider 41 connectable to carriage 4 by a removable screw 4<SP>11</SP>, whereby, when the carriage is connected to the slider, movement of the stylus 3<SP>1</SP> mounted on the carriage 3 in a direction perpendicular to the base 1 causes carriage 4 to follow an inclined path parallel to bar 5. Therefore, to convert vertical lines into slanting lines, e.g. in order to produce italic characters from Roman characters, lever 6 and slider 27 are disconnected by removing screws 6<SP>11</SP>, and slider 41 is connected to carriage 4 by screw 4<SP>11</SP>. When the image or matrix is followed by stylus 3<SP>1</SP>, a reproducing tool mounted at A on carriage 4 traces out a slanted reproduction of the original, the amount of slant depending on the angle at which bar 5 has been set. A greater slant is obtained by mounting the stylus at C on carriage 11. To reverse an original, carriage 4 is disconnected from the slider 4<SP>1</SP> and carriage 2 is clamped to platform 1<SP>1</SP>. The stylus is mounted at B on carriage 4 and the reproducing tool at C on carriage 11. To increase the length of the original, carriage 4 is disconnected from slider 4<SP>1</SP> and the lever 6 and slider 27 are placed in position. Slider 17 is set to the ratio by which the original is to be lengthened by means of scale E on bar 26. The stylus is mounted on carriage 3 and the reproducing tool at A on carriage 4. When the carriage 3 is moved parallel to base 1, its movement is transmitted by lever 6 to carriage 4 in the chosen ratio. Reverse lengthening is achieved by mounting the reproducing tool at C on carriage 11 and using scale G on bar 26. For shortening or reverse shortening of the original,'scales F, H respectively are used. Specification 701,635 is referred to.