Abstract: An improved lumbosacral backrest having a back engaging contour which is adjustable under power or manual operation to accommodate users' backs which vary widely in configuration and dimension. It has a contour defined by a segmented regulator spindle inserted between a foundation frame and resilient back support, the regulator spindle being adjustable along the back support and adapted to define a transverse plane of rigidity at the proper level and shape to provide comfortable support for the individual user's back.The backrest includes appropriate power means for actuating the regulator spindle to effect massaging action on the lumbosacral region of the back.It further includes manual means for adjusting the regulator spindle and which is operable when the power means for effecting massaging action has been deenergized.

Abstract: A lumbosacral backrest for use with chairs, beds and various other furniture, vehicle seats, and wheelchairs. The device, which may be portable or built-in, has an upstanding foundation frame of generally rectangular form, a yieldable back support on that frame, and a regulator spindle interposed between the frame and the yieldable back support. The regulator spindle is journalled for rotation longitudinally of the yieldable back support and may be stopped at any selected position within its range of rotational adjustment. This provides a transverse plane of rigidity across the back support at such selected position and thereby effects an adjustment in the contour of the back support. Adjustment of the regulator spindle may be accomplished manually or by power means.