US Patent 11530541 Adjustable form for concrete construction

An adjustable form for installing across an opening at an edge of a concrete slab includes a form member having a first form portion and a second form portion slidably connected to reach an adjustable effective length of the form member. The adjustable form further includes an extension mechanism connected between the first and second form portions and is operable to vary the effective length of the form member to fit across the opening. Tension exerted between the first and second form portions at the effective length is sufficient to keep the adjustable form in place.