FIG. 1 is a perspective view of a lifting column, showing our new design;

FIG. 2 is a right side elevation view thereof, the left side being a mirror image;

FIG. 3 is a front elevation view thereof;

FIG. 4 is a rear elevation view thereof;

FIG. 5 is a top plan view thereof;

FIG. 6 is a bottom plan thereof;

FIG. 7 is a perspective view of the lifting column in an alternate position;

FIG. 8 is a right side elevation view thereof, the left side being a mirror image;

FIG. 9 is a front elevation view thereof;

FIG. 10 is a rear elevation view thereof;

FIG. 11 is a top plan view thereof; and,

FIG. 12 is a bottom plan view thereof.

The broken line showing of a seating surface, leg support and headrest in FIGS. 1 through 12 is illustrative of environmental structure only and forms no part of the claimed design.