About Point Loading
a major factor in most of the above
The contact point between the spherical ball and item is very small and
subjects the item to an extremely high concentrated point loading.
Example: 50 lb. (22.68kg) item on one ball transfer, Generously say the
contact point area was 0.032 inch (0.812mm) diameter. The point load between
the ball transfer and item would be 58,100 lbs (26354kg) per sq/in (25.4mm2).
Don’t confuse ball transfer capacity with more important point
load capability of the item bottom. A 50 lb. capacity ball transfer is
overkill and not a factor if the point load capability of the vast majority
of items fall in the range of 5 to 30 lbs. The solution is not higher
capacity ball transfers, it is more ball transfers to reduce item point
loading! |
Examples:
A heavy item in a corrugated carton is likely to indent and flex, depending
on the quality of cardboard, would suggest a live loading of 5 to10 lbs.(2.27
kg to 4.54 kg) per ball transfer.
The same item on a smooth, hard, solid, flat, non-flexible quality
plastic tray would indicate a reasonable live loading of 15 Lbs. (6.8
kg) or less per ball transfer, for successful, minimum effort, movement.
The same item on a smooth, hard, solid, flat and non-flexible steel
tray would indicate a reasonable live loading of 30 Lbs. (13.61 kg) or
less per ball transfer, for successful, minimum effort, movement. Aluminum
15-20 Lbs. (6.8 - 9.07 kg)
Experience indicates that the most successful live load rates of ball
transfers, falls between 5 to 30 lbs. (2.27 to 13.61 kg) per ball transfer,
when all of these factors are considered. |
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