The principal parts of the guillotine are a table on which the material to be cut is piled; a movable back gauge (called the "back fence" in Europe), perpendicular to the table, against which the back edge of the pile rests; a clamp (or press beam) which compresses and secures the front edge of the pile, i.e., the edge to be cut; and a knife (or cutter) fixed in a cutting beam which descends immediately in front of the clamp, cutting through the pile, and stopping at a cutting stick set into the table. Pressure can be applied by hand with a screw spindle, but electric power is usual on both large and small machines.
All guillotines built for the printing and binding trades permit the squaring of a sheet, or section, provided that none of the dimensions exceeds the cutting length of the machine. Generally, on standard models, the size of the material to be placed on the table must not exceed its cutting length in either direction; however, some of the larger cutters are provided with longer back tables as optional equipment. Some cutters allow for trimming the shorter dimensions or splitting sheets. One of the most important features on some modern cutters is automatic spacing, which causes the back gauge to move a pre-determined distance following each cut.
Modern electronic guillotines have movements which are actuated by a series of relays and contactors brought into operation through the medium of a number of thyratrons, tubes, and photoelectric eye units. All operations are mechanical, and are set into motion by push buttons or by tripping micro switches which control the electronic circuit and, therefore, the cutter.
Modern guillotines also have safety devices which reduce the element of risk, assuming that the proper precautions are taken and the mechanism is not altered. Controls are designed to require that both hands be used to activate the final clamp pressure and cutting operations, and the machines are designed to stop the knife at the top of the stroke without possibility of a repeat cut.
Guillotines came into use in the late 1830s, when, in 1837, Thirault built a model with a fixed blade. In 1844 and 1852 Guillaume Massiquot patented machines similar to those in use today. Since the middle of the 19th century considerable improvements have been made by Fomm and Krause of Germany, Furnival in England, and Oswego and Seybold in the United States. (89 , 145 , 236 , 320 )
Timestamp: Saturday, 19-Nov-2011 13:18:41 PST
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