Structures Tech Insights · Product guide

Tech Insights · 2026-08-19

Conveyor Frames & Supporting Structures

#frames #structures #alignment #corrosion #installation

The frame is the reference surface everything else is aligned to. We look at steel-structure design rules (DIN 22101, ISO 5049-1), idler-mounting tolerances (ISO 1537), deflection limits and corrosion protection (ISO 12944).

The frame is the alignment datum

Every idler, pulley and loading point is aligned to the supporting structure. If the frame is out of square, twisted or deflecting under load, that error propagates directly into belt mistracking, uneven idler wear and seal failure. Good conveyor design therefore starts with the structure, not the components.

Steel-structure design rules

For mobile and heavy structures, ISO 5049-1:1994 sets the load groups (main, additional, special) and the rules for allowable stress, buckling and fatigue that DIN 22101 references for the conveyor as a whole. DIN 22101:2011 itself provides the simplified resistance model and the safety factors — fabric belts around S₀≈8, steel-cord around S₀≈6.7 — that size the strings, galleries and support steel. Over-looking these factors is a frequent cause of premature structural fatigue on long conveyors.

Idler-mounting tolerances

ISO 1537 governs idler dimensional and mounting geometry — shaft-end flats, roll face lengths and drop dimensions. Tight shaft-flat tolerances (typically +0.00 to −0.15 mm) prevent fretting and bracket-slot wear; loose fits let the idler chatter in its cradle. The frame must hold those tolerances across temperature cycles and under dynamic load, which is why bracket design and welding procedure matter as much as the idler itself.

Deflection and resonant behaviour

Stringer deflection should be limited so idler stations stay co-planar; excessive sag lets the belt trough vary station-to-station and invites spillage. Long spans also risk resonant vibration under start-stop and pulley-pass frequencies — a structural check (not just a static load check) is warranted on elevated galleries and transfer towers.

Corrosion protection

Conveyors in coastal, chemical and wet plants live or die by corrosion control. ISO 12944 defines the protective-paint systems and corrosivity categories (C1–C5 / Im1–Im3) that should drive the specification of primer, intermediate and topcoat for the structural steel. Galvanizing or stainless bracket hardware extends service life further in aggressive duty. HBXM supplies frames and galleries engineered to these alignment, deflection and coating rules for mining, port and cement installations.