Between the two pulleys c, c¹, and around the shaft a, is a muffle d, which receives at both ends the rounded heads of three, four, five, or more screws f, which act as levers. The levers are formed of a right and lefthanded screw, f, and f¹. The two screws are united together by means of a nut g, so that, by turning it, they are lengthened or shortened. The heads of the upper screws f¹, act upon the blocks e, e¹, contained in boxes supported by the plates h, h¹, through the centre of which passes the shaft a. These plates h, h¹, are fixed on the shaft a; they are of a smaller diameter than the inside of the pulleys c, c¹; their object is to keep the blocks e, e¹, from twisting.By moving the muffle d, to the left, the levers or screws f, f, will force the blocks e, to bear against the inside of the pulley c, placed on that side. The motion of this pulley will cause the muffle d, and consequently the shaft a, to revolve. By pushing the muffle d, on the opposite side, the blocks e, will depress the pulley c, and the blocks e¹, will bear against the pulley c¹, the band of which being crossed, will cause the shaft a, to revolve in a reverse direction.This shaft being furnished with a pinion, will transmit to a toothed wheel or rack, a motion in both directions at the desired instant, since it is only necessary to give the muffle d, a lateral movement from right to left, or from left to right, by means of a fork which acts on the part b.By placing the muffle d, half way between the two pullies c, and c¹, the blocks e, and e¹, will release the said pullies, and the shaft a, will be motionless.The patentee claims, ”the characteristic principle of the mechanical combination herein described, applicable to all cases where it may be useful, by varying the shapes or dimensions according to the power of the machines to which they may be applied.”
1858, Newton's London Journal of Arts and Sciences. New Series, volume 7, page 26