Patent GB-938455-A (GB)
Title: Improved processes and devices for model construction
IPC: G01C11/00
Filed: 1962-04-30
Abstract: 938,455. Maps; models. K. H. OVERTON. April 30, 1962 [May 2, 1961], No. 16507/62. Class 146 (2). An apparatus for the construction of topographical or geographical models comprises a table surface 1, Fig. 1, supporting a contour plan and sheet holder 2 having attached to the upper surface thereof a contour plan or map 6 and a sheet of rigid or flexible foamed plastic material 10 spaced in parallel relationship beneath the contour plan supported on rails 7, 8 and 9. Mounted slidably on the table surface is a carrier frame 3 having an upper arm 18 provided with a tracing stylus 23 arranged to coact with the contour plan and a heated cutting stylus 36 (Fig. 2, not shown) stretched taut between the two lower arms 19 and 20, and arranged in cutting relationship with the sheet material, such that the axes of both styli are in vertical alignment. The arrangement is such that movement of the tracing stylus 23 over the contour lines of the plan or map enables the cutting of corresponding contour areas from the section of sheet material. In another embodiment (Fig. 4, not shown), the cutting of the contour areas is effected by a photogrammetric stereo-plotter simultaneously with the determination of the contour line by a stereo-plotter, by connecting it to the carrier frame on which the cutting stylus is mounted. To facilitate the contour areas such as 61, 62, 66, Fig. 3, and their corresponding voided sheet sections such as 64 to be assembled the contour plans are provided with registration marks 57 to 60, Fig. 1, which are subsequently transferred to and cut out in the sheet sections. In the case of solid models the voided sheet section together with its contour area is placed on a model board 63, Fig. 3, having registration rods 53 to 56, and the contour area is glued in its registered position, whereupon the voided sheet section is removed and the process repeated until the relief model is completed. The steps formed by the contour areas are then filed or cut away. To indicate the representation of the contours on the relief model the sheet section may have attached to one or both of their surfaces a thin film of contrasting colours or the contour areas may be cut out from sheet sections of different colours. In the case of void or hollow models the voided sheets only are assembled on the jig assembly, the successive voided sheets glued together, and the steps removed by cutting off the surplus material. To portray the topographical features such as roads, railways or buildings upon the completed model so that it may be a true representation of the original contour plan or map, a photographic print of the features to be transferred to the model is made on a stripping film, the image film 81, Fig. 5, stripped from its base and attached to an image frame 82, having corresponding registration holes 83 to 86 and the frame rested on the registration rods 53 to 56, Fig. 6, on adjustable clamps (not shown). The topmost voided sheet section 64 is then superimposed on to the image film 81, clamped to the frame 82 and a diluted solvent for the stripping film brushed on the portion of the image film exposed through the void 65. The portion of the image film which has been softened by the solvent may now be stretched and manipulated into contact with the surface of the contour area of the model to which it adheres, the whole surface of the model being treated with an adhesive such as gelatine. The process is repeated for the remaining contour areas until the entire surface of the model is covered by the image film. Folding.-Flexible models which may be rolled up for carrying or mailing are constructed in a similar manner from a flexible foamed plastic.