Tension springs, also called extension springs, carry an initial tension in the closed coils and resist being pulled apart. Xinshunyan makes them with machine hooks, side loops, swivel loops and long straight bodies for garage doors, gym equipment, rocking chairs, sewing machines and general industrial assemblies.
Every part below is a production photograph. Each can be remade to your dimensions.
Most extension spring complaints trace back to the hook. A hook bent from the last coil without a smooth transition concentrates stress and snaps, usually inside the customer's finished product. Hooks here are formed as part of the coiling programme and the transition radius is kept generous.
Machine loops, double hooks, extended hooks and side loops are formed to match the pin, eyelet or bracket that the spring hangs from.
The closed-coil preload is set on the machine rather than stretched in afterwards, so the spring does not sag towards the bottom of a batch.
The same floor runs small instrument springs and long heavy-duty bodies for doors and trampolines, so a whole assembly can be sourced in one order.
Zinc, galvanised, nickel, white and black finishes plus stainless wire cover bathroom, garage and outdoor fitness applications.
From a sketch, a drawing or the part in your hand to an approved production sample
Nine finishing routes chosen against the environment the spring works in
What gets tested before a batch is allowed to be packed
Wire diameter, outside diameter, free length inside the hooks, hook type and the load you expect at working length. A sample works just as well as a drawing.
Yes. Mixed ends, such as a machine loop at one end and an extended hook at the other, are formed routinely.
It should never be pulled past the maximum extension we quote for the design, because the coils take a permanent set beyond that point. Tell us the travel of your mechanism and we will size the free length around it.
Yes. Stainless wire is stocked for bathroom fittings, outdoor equipment and washdown areas where a plated carbon steel spring would rust.
Send your drawing, your sample or your dimensions. Extension springs that pull a mechanism closed and hold it there.