Discussing FIG. 4, for structure participants 160, 160 the rollers 1 10a, 1 10b are positioned typically midway coupled a length of the body fellow member. Structure associates 160, 160 may incorporate lowered level regions 161 , 161 between your pair of rollers 1 10a, 1 10b and every conclusion of structure participant 160. Each conclusion 160a, 160b of every structure member 160 is welded to one of many couple of generally longitudinally focused frame participants 124. Although these lowered size places 161 , 161 will be to supply clearance for buckle 1 12 (Fig. 2), they can even be employed to decrease the firmness or spring season level from the structure associate to produce the desired tightness or springtime amount. Body participants 160 are about 18.3 ” very long.
 Discussing FIG. 6, for body associates 162, 162 the rollers 1 10a, 1 10b can also be located generally midway together a entire framework participant. Every conclusion 162a, 162b for each body associate 162 is slotted as at 163 to allow for a individual one of several cross bands 152, 156 or154 and 158, and is welded thereto. Frame associates 162 are about 17.75 ins extended.
 Referring to FIG. 7, for frame associates 164, 166 and 164, 166 the rollers 1 10a, 1 10b are placed near a single stop of the framework associate, because of the wish to evenly place the rollers throughout the structure 120 and as a result of geometric restrictions enforced from the several other body individuals the structure 120. Considering that picking out the rollers 1 10a, 1 10b close to 1 finish of the frame participant makes for a higher firmness or spring price, a lower level location for framework participant 164 and 166 is attractive to lower the tightness or early spring level to usually match that from other structure members 160, 162. To that conclusion, a lower elevation location 167 is provided upon an uppr side and also at that finish 164a in the structure participant 164, i.e. involving the rollers 1 10a, 1 10b and also the link with surrounding composition, which in cases like this is among the pair of generally longitudinally oriented frame associates 124. End 164a contains a further lowered level place on a lower part thereof in the form of a level 169 that may be reinforced on the tang 170 that is welded to the usually longitudinally oriented frame fellow member 124. Conclusion 164a is welded to tang 170 and to framework member 124. Other finish 164b of body associate 164 is slotted as at 171 to accommodate a individual one of the go across straps 152, 156, 158 and 154 and is welded thereto. Framework members 164 and 166 are about 13 in . very long.
 The above mentioned-detailed curler helping structure member components, structure associate go across-sectional shapes and dimensions, body associate lengths, placements of your rollers down the measures from the body participants, and body associate end conditions are simply exemplary and illustrative; othermaterials and shapes,
, roller roles, and conclusion circumstances may also be used to make acceptable stiffnesses/spring charges.dimensions and lengths It is believed that the above-described shapes, lengths, materials and dimensions roller positions, and end conditions produce about a 3 degree angle of tilt a if a 3,500 pound point load is placed at the centerline of one of the rollers 1 10a, 1 10b, as shown in FIG. 5B, as expected through numerical simulator, i.e. by way of finite component assessment. Other stiffnesses/spring rates can be utilized; the 1 166.67 kilos per education firmness/spring season rate is simply exemplary and illustrative.