Identical chain sprockets 1 and 9 rotate counterclockwise about fixed axes A and B. Chain 2 runs over sprockets 1 and 9. Motion is transmitted to chain 2 by sprocket 1 so that the top strand travels to the left. Link a of the chain has a project ion. As the chain moves, its link a engages upper latch 3, hinged to slide 4 and traversing it to the left until the arm of latch 3 runs against stop 5 and the latch is disengaged from link a and slide 4 stops. When chain link a reaches lower latch 6, also hinged to slide 4, the latter is traversed in the reverse direction until the arm of the latch runs against stop 7 which disengages the latch so that slide 4 stops again. Screw 8 has right- and left-hand threads and is connected by screw pairs to stops 5 and 7. Screw 8 is used to adjust stops 5 and 7 which limit the travel of slide 4.
$3555$CFL,SE$