Two patents granted to William A. C. Oaks appear on the Centennial Keystone Apple Parer made by the Keystone Hardware Manufacturing Company, a part of Reading Hardware Company (Thornton, 1997). The inventive claim for Oaks's patent of December 10, 1872 includes a bent frame to allow parings to fall free from the machine and a mechanism for pushing the knife clear of the apple after paring so that the fruit can easily be removed (Oaks, 1872).
Oaks used the same general design and referenced his earlier patent in his letters patent dated July 22, 1873 (Oaks, 1873). The innovation for Oaks's 1873 patent was for a mechanism that temporarily stopped the knife while the forks continued to make one revolution, "...the knife will make a positive stop until the apple has made one revolution, so that that part of the apple near the prongs of the fork is fully pared before the knife commences to start around the apple." The mechanism consists of missing teeth on the turntable gear. A large tooth on the spur gear connected to the turntable gear re-engages after one revolution of the fork, see first image below.
In our video the knife stop is difficult to see as it occurs so quickly. Like most parers the Centennial would be mounted at the corner of a table.