Drawing of a pantograph, showing linkages of Sorenson's engraving pantograph (1867).
A pantograph (from Greek roots παντ- 'all, every' and γραφ- 'to write', from their original use for copying writing) is a mechanical linkage connected in a special manner based on parallelograms so that they move in a fixed relationship to each other.
History
The first pantograph was constructed in 1603 [1] by Christoph Scheiner, who used the device to re-create diagrams, but he wrote about the invention over 27 years later, in "Pantographice" (Rome 1631). [2] One arm of the pantograph contained a small pointer while the other held a drawing implement, and by moving the pointer over a diagram, a copy of the diagram was drawn on another piece of paper. By changing the positions of the arms in the linkage between the pointer arm and drawing arm, the scale of the image produced can be changed. A more complicated version called the eidograph was developed by William Wallace in 1831.
Besides use in copying plans or diagrams, pantographs have been used in milling and engraving to control the carving of copies from a guideline pattern or object.
Modern versions of pantographs can be found in many toy stores.
Other uses
The pantograph has been applied to other fields in addition to drafting. A type of pantograph was used in the early days of sound recording to duplicate phonograph cylinders in the late 19th century (see below). Another application of the pantograph sees it incorporated into a milling machine with a revolving cutter instead of a pen and a tray at the pointer end to fix precut lettered plates. In this way machinists can neatly and accurately engrave part numbers and such onto a part.
The device which maintains electrical contact with the contact wire and transfers power from the wire to the traction unit, used in electric locomotives and trams, is also called a "pantograph".
Cylinder duplication
One advantage of discs in the 1890s was that large numbers of discs could be stamped quickly and cheaply. In 1890, the only ways of producing inventories of cylinders were to mold the cylinders (this process turned out horrible cylinder copies), record cylinders by the "round", over and over again, or to acoustically copy the sound by placing the horns of two phonographs together or two hook the two together with a hollow rubber tube (one phonograph recording and the other playing the cylinder back). Edison, Bettini, Leon Douglass and others solved this problem (partially) by mechanically linking a cutting stylus and a playback stylus together and copying the "hill-and-dale" grooves of the cylinder mechanically. When molding improved somewhat, molded cylinders were used as pantograph masters. Some companies like the United States Phonograph Co. of Newark, New Jersey, supplied pantograph masters for smaller companies so that way they could duplicate the cylinders, sometimes pantographically, to fill their record catalogs.
See also
Notes
- ^ "The Galileo Project - Scheiner, Christoph" (history), Al Van Helden, Galileo Project, 1995, webpage: GPsch.
- ^ The full title of "Pantographice" is "Pantographice seu Ars delineandi res quaslibet per parallelogrammum lineare seu cavum" (Rome 1631).
External links
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