GB631557A - Improvements in means for producing stencils in thin sheet metal or the like - Google Patents

Abstract

631,557. Cutting shaped holes in plates. HEATH, F. C. Oct. 29, 1947, No. 28853. [Classes 83 (iii) and 83 (iv)] .Stencils of small dimensions are cut in sheetmetal or like material by a reciprocating punch, the work being moved under the punch by a pantograph manually operated to follow a pattern. The work 1 is clamped by screws 2 onto a table 4 which runs on ball-bearings in grooves 6 on a slide 3 which runs in similar grooves 7 at right angles to grooves 6 in the machine frame. The table 4 is pivoted at 10 to the arm 9 of a pantograph which is pivoted at 11 to the machine frame, the arm 18 of the pantograph carrying a tracer 12 which is caused to follow the outline of depressions in patterns secured to a table 14 by screws, wedges, &c. The pivots 10, 11 are adjustable to vary the scale of reproduction. The punch 15 is reciprocated rapidly in a fixed head 13, normally just clear of the work, but on actuation of mechanism by a pedal &c. or automatically, the punch is caused to penetrate the work and enter a fixed die 17 projecting through an aperture in the table 4. The automatic mechanism may consist of insulating and conducting strips on the pattern which cause the tracer to complete a circuit which controls operation of the punch to assist in the formation of supporting bridges in the stencils, or alternatively a contact on the arm 18 may open and close a circuit for controlling the punch as the tracer is raised or lowered in the pattern. The punch passes through a stripper plate 16 and the plate, punch and die are readily removable for replacement by tools of different size. The Specification refers to " Ingenious Mechanisms for Designers and Inventors," Volume I, (Jones), published by the Machinery Publishing Co., Ltd., 1930, page 135, which describes a mechanism suitable for controlling the punch.