My problem is terminology: for business use I am seeking a canopy /marqee that expands or contracts?

The type I seek is seen on all major football grounds and are entry tunnels to the dressing rooms; they have a metal trellis that expand or contracts and are presumably on wheels. I can only find irrelevant options suitable for playgrounds or weddings. I should also like to know a supplier in the East Midlands - preferably to buy rather than hire.