PART IV | LESSON 14: CHANGING DIRECTION AND ELEVATION MATERIAL HANDLING ACADEMY
DRIVING QUESTION What happens to the package when the system has to turn, climb, or drop?
Two cartons drawn at the same decline angle. The first has a centered center-of-mass dot whose vertical plumb line falls in the middle third, labeled stable. The second has the load shifted toward the downhill end, its center-of-mass dot moved forward and its plumb line falling into the leading third, labeled tips forward, with a gold tipping arrow.

The same carton, two loads. Centered stays in the middle third; shifted forward crosses into the leading third and tips.

The Three Transitions

Curve

The diagonal of the package, not the width, drives the belt width. The curve becomes the system spec. Run it first.

Incline

Danger is startup. Inertia and load shift push toward the trailing edge, so the box wants to tip backward.

Decline

Danger is the stop. Both push toward the leading edge, so the box wants to tip forward. Mind the gravity pitch.

The Thirds Method

Leading third

Plumb line from the center of mass lands here: tips forward.

Middle third

Lands here: generally stable. Draw the worst-case load, not the centered one.

Trailing third

Lands here: tips backward.

DESIGN PRINCIPLE See what the static number can't.