GB465576A - Improvements in or relating to drawing tables - Google Patents

Abstract

465,576. Adjustable tables. GRAF, V. Nov. 27, 1936, No. 32464. Convention date,. Nov. 29, 1935. [Class 52 (iii)] A drawing-table adjustable both for height and inclination about a main axis is held in position by clamps operated by a nut under the control of a pedal. The table is supported by arms 4, Figs. 14 and 5, secured to a tube mounted in the main axis at the tops of the standards 9 and also by arms 5 carrying counter weights 7 and pivoted to levers 6 rotatably mounted on the tube. The arms are all clamped to the standards by a central rod 10 and nut 18 having an operating arm 19 connected, as shown in Fig. 6, by a link 22 to a lever 20 operated by a pedal 23. As the pedal and lever 20 are moved from the free position shown in dotted lines to the locking position shown in full lines, the mechanical advantage increases. When a ball bearing is interposed between the nut 18 and the adjacent standard, the stop 24 for lever 20 is so arranged that the lever and link 22 are in line thus locking the nut; but if the ball-bearing is omitted, the stop 24 can be advanced so that the parts are clamped before the lever and link are in line, the additional friction preventing slacking back. Resistance to angular movement of the board may be increased by additional friction introduced between arms 6 and the standards 9 by the means shown in Figs. 10 and 11. An extension 27 on one arm 6 carries a bolt 32 which moves through a slot in a sector on standard 9 and engage the sector with a varying force depending upon the pressure exerted by the wheel nut 33 upon spring washer 34. Additional friction for both the lifting and the tilting adjustments may be obtained by additional plates 38, Fig. 12, between arms 4, 6, held against rotation by rod 39 mounted in standards 9. These plates may be extended downwards to support a drawer 44, Fig. 14, or a writing table.