Fecha de publicación: 31/10/1918 Fuente: WIPO "bee" Comprises the combination of a bed frame a trans versely extending rod journalled on the frame adjacent to the head end supporting links on the bed having one end rigid with the rod and torsion springs connected with the rod and bed frame by which tension is applied to the springs as the bed is oscillated about the rods as a fulcrum. Other features are contained in invention [ 7 figures 9 claims ].