Considerations Beyond Load Weight – When Selecting the Correct Scissor Lift Table
Understandably load weight is the top consideration when selecting the correct scissor lift table. The weight consists of both the live load weight; live loads are the items that will be placed on the unit and removed from the unit. It is also important to consider the dead load weight; the weight that is applied to the unit on a permanent basis such as conveyor, weight scales, or fixtures. A good description includes how the dead weight will be supported by the platform and attached to the platform is necessary so that Alfacon Solutions’ engineers can determine if the structure of the platform can satisfactorily support the incurred loads without deflection or twisting. Any unbalanced loads such as offset conveyor drive motors must be revealed so that the center of gravity for fully loaded and minimally loaded configurations can be determined.
Items that require factory consultation include special environments such as freezers, proximity to high heat, or damp locations. Likewise, hazardous environments such as explosion proof for dust or for vapor must be determined to guarantee compliance for explosion proof electrical standards.
Other issues to consider in the selection of a scissor lift table include the desire for special finishes such as stainless steel, polyurethane paints, or epoxy paints. The use must be reviewed looking at high cycle requirements often requiring ultra-high cycle units, or self-propelled units, bellows and roller shades.
Once the total number of cycles per year are calculated, that number can be compared to the “warranty life” and “expected life” as explained in the Alfacon Solutions’ warranty. There is a large difference in the warranty life of a standard unit and an ultra-high cycle unit; there is also a significant difference in price. If the application requires engineered-to-order elements, Alfacon can often modify a standard unit designed to better fit the application and the budget.
Usually the standard speed offered with each lift model is satisfactory for most applications, but since Alfacon offers custom solutions, the ability to increase faster speeds can be met. The formula for horsepower is work (force X distance) divided by (550 X time). The less time to do the work, the more horsepower that will be required. In the case of units with internal power units, any increment in horsepower size will require moving the power unit externally because the larger motors will no longer fit within the structure. As horsepower goes up in size and cost, so do the electrical controls, hydraulic pumps, and valves.
Speed cautions begin at speeds of 15 fpm (feet per minute) to 24 fpm. At these speeds sufficient energy is amassed so that damage can occur to the units over time unless something is done to decelerate the units at the limits of travel. The most detrimental conditions occur when going up empty and down fully loaded. In this speed range, depending on the actual application, corrective engineering such as adding shock absorbers at the bottom of travel will provide adjustable flow controls.
Travel and load increments provide the necessary information to determine what precautions should be taken. Weight alone cannot be the single determinant of which scissor lift table is best.