Gear 1 is free y mounted on fixed stud 10 and 2 driven at uniform velocity about fixed axis B of stud 10. First driving arm 2 is rigidly attached to (or integral with) gear 1, while second arm 3 is pivoted to gear 1 and is held in its raised position (shown by the dash lines) by spring 4 attached to pin a of arm 3. Spring-loaded pin a slides around fixed cam 5 (inot shown in the top view). Geneva wheel (spider) 6 rotates about fixed axis D and has two slots d and two slots b, symmetrically located. When pin f of arm 3 engages a slot b of Geneva wheel 6 it imparts acceleration to the wheel until arm 2 reaches centre line BD. At this point gear segment 7 meshes with its mating segment 8 which is rigidly attached to Geneva wheel 6. This rotates the latter at uniform velocity. The rear wall of slot b is shortened and rounded off at g so that pin f cannot interfere with the uniform motion imparted by the gears. At the instant the gear segments 7 and 8 pass out of engagement, arm 3 is turned about axis A into engagement with a slot d of Geneva wheel 6. This is accomplished by cam 5 whose lobe actuates pin a of arm 3. This instant is the one shown. Upon further rotation of arm 3 it decelerates Geneva wheel 6 to a stop. At this point arm 3 passes out of engagement with slot d of Geneva wheel 6 and the concentric outside locking surface of link 9, rigidly attached to gear 1,intent engages a concave locking surface e of Geneva wheel 6 to pdrevent its unintentional rotation during its idle periods.
$2646$PG,GW$