be well recognized in the art that a wide variety of other resilient members or other types of biasing members other than springs can be employed as the means 43 preferably the wheelchair 10 includes a locking assembly 48 best shown in fig3 that serves to fix the seat assembly 12 in a horizontal alignment when the user desires as during travel of the chair 10 the locking assembly 48 is formed of a locking lever 49 having a lower end 50 that is pinned to one of the side frame horizontal members 20 at 50a and an upper end 51 that has a forwardly facing notch 52 the lever 49 is movable from a forward position in which it is adjacent a forward limit of movement abuttment 53 and a rearward position in which it is adjacent a locking stud 54 as the lever 49 is moved rearwardly the pin connection 50a allows sufficient play between the lever 49 and the member 20 to move the upper end 51 of the lever 49 outwardly from the member 32 to move past the stud 54 when the lever 49 is in its rearward position the locking stud 54 that extends outwardly from one of the side support members 32 is received in the notch 52 so that the lever 49 supports.