H M Quackenbush .22 rimfire rifles

I recently bought a Quackenbush .22 rifle. Eventually it will be part of a display along with some of his nutcrackers.

Doing some research I found that some (probably later?) have a flat spring on the swinging breach and a triangular "retractor" presumably to retract the firing pin between shots. Does anyone know, or have a reference to the date of change? Mine, which was sold as an "antique", does not.

I was not able to find either a good website on these guns, or a reference to an authoritative book. I did find a bunch on the air rifles.

Does anyone happen to have a reference to the date of one or more of his gun patents, or numbers. Given a date or a number I can retrieve the patents (I already have for the nutcracker). The available online databases do not allow inventor or keyword search that far back.