Keywords: Duplex Escapement.png Drawing of duplex escapement invented by Thomas Tyrer around 1760 Parts A escape wheel B locking tooth C impulse tooth D pallet E ruby roller The pallet is shown in dotted lines because it is mounted above the escape wheel and ruby roller The pallet and roller are on the balance wheel arbor but the balance wheel itself is not shown Alterations using a graphics editor I drew in one of the impulse teeth that had apparently been left out of the original drawing and replaced the original letters identifying parts with colored ones in a different order Downloaded from http //books google com/books id 7DcDAAAAQAAJ pg PA163 Harry Leonard Nelthropp 1873 A Treatise on Watchwork Past and Present E F N Spon London Fig 12 p 163 on Google Books 1873 Harry Leonard Nelthropp Public domain - author died more than 70 years ago PD-old Duplex Escapement |