GB292795A - Improvements in and relating to draughting machines - Google Patents

Abstract

292,795. Nahman, G. July 28, 1927. Draughting - machines. - In a draughting- machine of the kind comprising two parallelogram linkages of which the sides 5, 12 are connected together, the connection is in the form of a pivot permitting angular movement between the said sides so that the instrument can be folded, for packing purposes, into a position in which all the arms of both parallelograms lie in the same direction. The hinges connecting the pa.rallelogram links are of such form that in the folded position all the sides of each parallelogram lie in the same plane with each of the long sides in alignment with one of the short sides. The pivot connecting the two parallelograms consists of a bolt passing through lugs 10, 11 and engaged by a wing-nut 13 which is tightened to secure the sides 5, 12 against relative angular movement while the instrument is being used. The long sides 3, 4 of the upper parallelogram are of tapered form in elevation, Fig. 2, and the hinges 6, 7 connecting them to the side 2 are of such length that the long sides 14, 15 of the lower parallelogram lie, in the folded position, in the space between the sides 3, 4 and the anchor plate 1 carried by the side 2. The draughting head 17 is provided with pins 24, Fig. R, entering key-hole slots 23, Fig. 7. in the side 16 so that these two parts can be readily detached for packing. The vertical ruler 19, is provided with a forked plate 25. Fig. 6. passing over the pivot 26 so that this ruler can also be readily detached. When the rulers are detached they can be packed as shown in Fig. 3, so that the entire instrument does not occupy more space than the folded parallelogram. For raising the ruler above the drawing surface when lines are being drawn in ink, an inclined groove 28, Fig. 4, may be formed in its lower surface and a wedge-shaped member 29 can be adjusted in this groove and clamped by screws 30 and a spring 32. Instead of the plate 1 a tongue may be carried by the side 2 and. clamped near the top left hand corner of the board.