Rotary actuator, especially for adjustable furniture, including beds and bottom for beds

Abstract

A rotary actuator, in particular for adjustable articles of furniture, including beds or mattress supports, for incorporation in a structure for adjustment of an element in it, e.g. adjustment of a backrest section and/or leg-rest section in a bed or mattress support, said actuator comprising an electric motor ( ) which is connected by a drive shaft with a transmission ( ), which is in turn connected by a power take-off with a planetary gear having a sun wheel ( ) connected with the power take-off of the transmission, first and second internally toothed outer rings ( ) which are rigidly interconnected and have the same toothing, an internally toothed intermediate ring ( ) positioned between the first and second outer rings so that it can rotate about its axis relative to the outer rings, a plurality of planet wheels ( ) in engagement with the two outer rings and the intermediate ring and the sun wheel, and wherein the intermediate ring has a mounting bracket ( ) for connection with one part of the structure, and wherein the outer rings or their rigid connection has a mounting bracket ( ) for connection with the other part of the structure. A strong and comparatively noiseless as well as relatively inexpensive rotary actuator may be provided hereby. It may be constructed with a jamming protection arrangement and emergency lowering function.