When using the wheelchair's standing function, the vertical position of the user's bottom changes in relation to the back pan. In this case the back slides over the back pan, with the arm rests and head support no longer being in the correct position. In the standing position they are approx. 8 – 10 cm too high and hence no longer fulfill their function. Assembling a support frame on a drylin® W rail with several housing bearings solves this problem, with the wheelchair parts always remaining in the correct position to the user. The reasons for using the igus® products were the low weight plus the very high stability and torsional stiffness.