Let A, A, represent two magnets revolving on axes. Let B represent a larger magnet hanging on an axis, pendulum fashion, between the two former.
As the poles of the two smaller magnets lie in the same direction, the effect will be to draw the larger magnet toward that on the left hand, while it is at the same time repelled by that on the right; but, while this is going on, the upper end of the large magnet raises, by means of a guide wire, the tumbler D, which, just before the magnets come in contact, passes the perpendicular, and falls over, carrying with it the lever connected with the two wheels, C, C, and causing them to perform a quarter revolution; these wheels are connected by lines with two small wheels fixed on the axles of the two mag-nets A, A. While the former make a quarter revolution, the latter turn half round. Patented in 1829.
(Subsection 963, from p.386)
From: Gardner D. Hiscox, M.E., Mechanical Appliances and Novelties of Construction (1927), Norman W. Henley Publ. Co.