I've got a couple that look just like the one in your photo. One is a KD and one is a New Britain. Columbus may have brought them over for all I know. Anyway, I too got severely frustrated having them flop over on me. So, I built the one below. It's kind of a copy of one I saw on the internet somewhere for sale. It has worked well with springs that are 200 lbs on the seat and 600 open. It's slow but hasn't flopped once, so I consider it a success.
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