Cevedra Blake Sheldon was a prolific Park Slope architect/builder who constructed a great many Park Slope buildings including the entire west side of 7th Avenue between Garfield and 1st Street, the 3 matching corner buildings at the intersection of Garfield & 7th, and the Verona apartment building at 7th Avenue and President Street, among other buildings.
It turns out that Cevedra B. Sheldon was a designer/inventor as well.
On February 1, 1876, Sheldon was granted a patent for the invention of a new kind of reclining lounge chair/"invalid chair". The chair went into mass production by the Marks Adjustable Folding Chair Company of New York:
The Marks company defended its product line assiduously, bringing suit against imitators:
Many of these folding chairs appear to have survived and to come up for auction fairly frequently. A casual search on "Cevedra B. Sheldon" yields the following examples currently for sale: