https://patentimages.storage.googleapis.com/de/5d/14/a57ffad14ccd94/US600457.pdf

https://patentimages.storage.googleapis.com/aa/bc/8c/ca152a00b76d05/US577671.pdf

https://patentimages.storage.googleapis.com/b5/62/b7/bb55a0b2cf4518/US567818.pdf