The Engineering Process  

1. The load and the moment produced by the load are used to select the lift family. The standard used is the moment at 12" forward of the lift's carriage. Thus, a 100 lb load with the load center at 12" produces a moment of 1200 in-lb.

2. The width of the lift will depend upon such variables as the width of the object to be straddled (d) allowing clearance for inward turned casters. The lift's width may also depend upon constraints such as doorways, machine uprights or cart widths. Lateral stability calculations may affect width as well.

3. The leg profile may depend upon crawl space available for the lift's forward projecting legs. Without any crawl space, there are two options: A counterbalanced lift without any legs; or, it may be possible to turn the lift 90 degrees and parallel park it for side movement of the load.

4. Caster diameter (F) should be the largest practical subject to  constraints. Curves have been developed, relating push force to wheel diameter on different floors. Large wheels are used for carpeted or rough floors.

5. Leg length (G) depends upon space, maneuverability and most important, stability. The usual criterion is recovery from a 10 degree tilt with maximum load at teh highest position. At times recovery from a 12 degree or 15 degree tilt is required.

6. Mast length (B) is determined by defining the lowest and highest load levels, taking the difference to determine the required excursion. For Models A150 through A125, add 14" to the excursion (for the carriage and clearances). for B350, add 19". For A800, add 24" if a platform is to travel from floor level to 58" adding 14" results in a 72" long mast. If the maximum height is 62" the next standard length will be 84". Special mast lengths may be specified as well. At times the maximum mast length and the resulting lift height (A), will be constrained by overhead obstacles. In such instances, a telescoping mast may be specified.

BACK TO TOP