I found this pen clip in the ground this week. It has a patent date of 1911 stamped on it.
I have found a few others online that are for sale, but oddly they have a stamped date of 1910 on them. My best guess is that they were patented in the USA in 1910 and in Canada in 1911.
Page 851 of the 1912 Sears Roebuck Catalogue has a similar item called a Fountain Pen Protector that was included free with each fountain pen purchased.