GB1440439A - Apparatus incorporating pivotally interconnected members - Google Patents

Abstract

1440439 Counterbalancing pivoting members eg drafting tables ONWAY CONSTRUCTION CO Ltd 24 Sept 1973 [25 Sept 1972] 44288/72 Heading A4H Apparatus, e.g. a drafting table, comprises a first member, e.g. pedestal 15 to which is horizontally pivoted around axle 17 a second member, e.g. arm 12 and third member, e.g. table top 13 pivoted on the arm over horizontal parallel axle 21; a first counterbalancing system between the first and second members comprising cam 22 fixed relative to one member, e.g. 15 and member 23 acting around the cam under the load of spring 24 connected between the members, a second counterbalancing system between the second and third members comprising cam 35 fixed relative to one member, e.g. 13 and member 39 acting around the cam under the load of spring 40 connected between the members; and a further cam 31 fixed relative to the third member with the spring of the first counterbalancing system acting around the cam 31, e.g. via lever 26 and roller 33, whereby within a predetermined range of angular settings of members 12, 13 with respect to member 15, the turning movements of members 12 13 are substantially counterbalanced around axles 17, 21. With arm 12 horizontal member 13 is pivotable from substantially vertical as in Fig. 2 to a horizontal position in which case spring 40 is tensioned to act around lobe 38 of cam 35 to counterbalance around axle 21, while lobe 32 of cam 31 acting via lever 26 releases tension in spring 24 to counterbalance about axle 17. With arm 12 and member 13 vertical as in Fig. 4, lobe 37 of cam 35 tensions spring 40 to counterbalance member 13 and lobe 34 of cam 31 eases spring 24 which is off the cam 22 since member 2 needs no counterbalancing. The table may be locked by screws 46, Fig. 6 pressing disc 42, 42', Figs. 1, 6 secured to respective axles against set screws 48 under the action of respective springs 72, 72', and released by depressing handle 65, Fig. 8 pulling on cables 60, 60 connected to screw levers 47, 47'. By moving handle 65 to one side or the other one or other or both locking screws are actuated by handle lugs 68, 69 engaging with cable levers 58. The center of gravity of the table top may be altered by an adjustable weight 74 and the arm 12 move up to stop 73.