I'm afraid the exact word you need for 'patins' depends entirely on their actual form and function, there really isn't a single, universal word in EN that you could use and be right in every context; you really need to ask you client to supply more details of the equipment, a drawing, or something to guide you.

Just remember that 'patin' shares the same root as 'patiner' = 'to skate', and usually relates to something that is meant to slide / glide / slip / move freely.