Here are links to the US Patents of 6 pickgun designs.
These happen to be the 6 patents that Minnery references in his book on Pick Guns.
For those that are not aware, the text and images of patents are not subject to copyright laws and may be freely shared.
http://www.voyam.com/pat1403753.pdf
http://www.voyam.com/pat2309677.pdf
http://www.voyam.com/pat2565254.pdf
http://www.voyam.com/pat3264908.pdf
http://www.voyam.com/pat4156375.pdf
http://www.voyam.com/pat4606204.pdf