It is the classic and most popular type of innersprings made of a 5-turn (convolutions) steel coil interconnected in rows by helical wire. Bonnell innersprings are reliable, durable and have very good resilience. The coils are manufactured from oven-tempered steel wire (to 300oC), phosphate coated and have a tensile strength of 1600-1800 N/mm2.
We manufacture spring units with 2,00mm and 2,20mm thickness wire, with or without flat steel strip border frame 1.4mm x 10mm. Height can vary from 10cm for a 4-turn coil to 15cm for a 5-turn coil. Coil count per particular size can also vary with a higher number leading to a firmer mattress. Other specifications are possible.
For transportation purposes in order to maximise the loading capacity inside a container, the innerspring units are roll packed.