Stair Assist giving seniors a lift.

It all started as an innocent weekend hosting friends. But when one of Bob Warren Sr.'s elderly visitors proved too unsteady on his feet to climb the stairs to the bedroom, it launched the Portland industrialist on a second career.

Warren, co-founder and retired chief executive and chairman of Cascade Corp., began thinking about a system that would help the aged ascend and descend stairs. Then 72 years old, it was a concern Warren could relate to.

Four years and a reported $3 million later, Warren's new company, Stair Assist Corp., is ready to roll out its first product. The device consists of an electrically powered motor that moves a sturdy support bar up and down a wall-mounted rail along a set of stairs. Stair Assist will begin selling the unit next month in Portland and hopes eventually to take it nationwide. Warren, always one to think big, thinks the Stair Assist product will be a big hit in the residential market and beyond. "I envision the time when a good number of public buildings will have the rail," he says. "It's an enormously useful tool for the disabled and the …