摘要 |
The device has a removable support element attached to a lower crosspiece (4) and an intermediate crosspiece (3). The support element consists of a padded backrest in the form of a rectangular or trapezoidal plate adapting to a general shape of a frame. The support element is fixed on a same face of a plane of the frame on which another support element is fixed so as to extend the former support element on an area covering whole or a part of the crosspieces and extend the former support element on a space between side posts (1, 1') in the vicinity of the crosspieces.
|