GB1412892A - Kinematic mechanisms - Google Patents

Abstract

1412892 Loading docks INTERNATIONAL BUSINESS MACHINES CORP 10 Oct 1973 [17 Oct 1972] 47193/73 Heading B8E [Also in Divisions A4 E1 and F2] An extensible linkage, for mounting a computer control relay rack or drawer such that the heavy drawer may be readily extended from its home or nested position for servicing, maintains parallelism of the drawer during movement to prevent the drawer tending to drop at its outer end when fully extended. As shown, the linkage comprises two identical sets of trusses mounted at each side of a movable drawer supporting platform 24 and each comprising an inner parallelogram linkage 20, comprising 18, 23, 24, 25 i.e. the platform 24 is carried by and forms part of this inner linkage 20, and an outer parallelogram linkage 10 comprising 15, 16, 17, 18 i.e. the beam 18, which is common to both linkages 10 and 20, and a fixed base 16 forming parts of this outer linkage 10 which is movable about fixed pivots 11, 12 on the fixed base 16. Each inner parallelogram linkage 20 is movably carried by its adjacent outer parallelogram linkage 10 by upper pivot points 13, 14 each end of the common beam 18, the beam 25 of the inner linkage 20, rigidly carrying an arm 30 arranged at right angles thereto for joint movement about their common pivot point 13, which arm 30 is pivotally connected at its outer end 31 to the upper end of a beam 32 the lower end of which is pivoted about fixed pivot 11. The arrangement is such that within stated limits of outward movement as the linkwork trusses 10, 20 are outwardly extended as at Fig. 3b from the nested position of Fig. 3a, the arm 30 and beam 32 maintain parallelism of the support platform 24 relative the fixed base 16. It is stated that movement of the support platform 24 in the opposite direction as at Fig. 3c whilst still maintaining parallelism slowly raises the platform 24 relative the fixed base 16. Alternative uses for the extensible linkwork include a portable bridge, loading or unloading docks or ships or loading ramps generally. A number of such extensible linkwork mechanisms may be superimposed in nested assembly (Fig. 3d, not shown) to form steps.