Coupling elements and spiders

What it does inside the pump

The element is the flexible piece that sits between the two coupling hubs — a spider in a jaw coupling, bushes in a pin coupling. It carries the torque, damps the torsional shock at start-up, and is deliberately the weakest part of the drive train so that it fails before the shaft does.

How it fails, and what you see first

Elements harden with heat and age, then crumble or tear. A hardened element stops damping start-up shock and starts transmitting it straight into the bearings and the shaft, so a machine on old spiders will also eat bearings. Tearing on one side only points at misalignment; even, all-round crumbling is ordinary age and heat.

What to send us so the part is right

Coupling make and size stamped on the hub, or the pump model plus the motor frame. If the old element is in pieces, measure the jaw spacing and the outside diameter of the hub. Tell us the duty temperature — standard NBR is fine to about 80 °C, polyurethane handles more load, and high ambient needs a different compound.

Which models take this part (273)

Grouped by pump family. Model numbers in blue have their own page with the full specification table; the rest are supplied from the same frame — send the model and we confirm against the drawing.

Other parts for the same machine

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