is possible to adjust the number of rotations that the roll bar 36 is permitted to go through before the intercepting ledge 166 on the internal roll bar support wheel 152 intercepts the stopping ledge 150 on the back side of the finger abutment ring 149 on the head 144 of the threaded shaft 72 when the pressure driving the screwdriver 524 rightward in fig2 is released the setting retention spring 60 drives the plunger 46 and threaded shaft 72 to the left in fig2 until the four locking lugs 142 engage locking fingers 140 on the cylindrical housing 64 and the tips of the locking fingers 140 rest against the finger seat 148 fig5 b of the finger abutment ring 149 once the interlocking lugs 142 are locked into the locking fingers 140 the threaded shaft 72 again becomes effectively fixed to the left end cap 24 and thus remains stable during rotation of the roll bar 36 fig2 is a fragmentary view taken along line 21 u2014 21 of fig2 and depicts disengagement of the locking lugs 142 two of which are depicted from the locking fingers 140 fig2 is a partial cross sectional view taken along line 22 u2014 22 of fig2 through the center of the internal roll bar support wheel 152 the threaded barrel 154 of the internal roll bar support wheel 152 is shown as threaded onto the threaded shaft 72 the edge of the threads shown in phantom as a ring around the threaded shaft 72 placement of the internal roll bar support wheel 152 within the roll bar 36 is also clearly visible in fig2 the.