This design reminds me of an air compressor which is used on large substation circuit breakers to activate the re-close mechanism. The compressor had a patent of 1923 if my memory serves me. In the air compressor, a single solid piece of steel was machined into two pistons (one on each end) with the crankshaft passing through the mid-point acting as a crankshaft of sorts. I always thought there would be an engine application to the basic idea and this seems close to it.
