Patent GB-190314901-A (GB)
Title: Improvements in or relating to Variable Speed Gearing.
Inventor: PRENTICE JOHN
Filed: 1903-07-04
Granted: 1904-06-16
Abstract: 14,901. Prentice, J., and Prentice, A. W. July 4. Variablespeed gearing.-A series of toothed or chain wheels is secured by free-wheel clutches to the driven shaft and always engages with a corresponding series loosely mounted on the driving-shaft, to which the wheels may be secured by friction clutches. Pinions A, A', A<2>, Fig. 1, are secured to sleeves E, E<1>, E<2>, each formed in two parts to admit of longitudinal motion of the parts carrying the friction clutches F, F<1>, F<2>, which are provided with a facing of wood, leather, &c., if desired. The pinions A, A', A<2> gear with pinions B, B', B<2>, secured by free-wheel clutches B<3> to the hubs b, b<1>, b<2>, which are secured to the driven shaft D by split and tapered sleeves d. Normally, the friction clutches are pressed together and against the clutch C', which is secured to the shaft C, by springs G, G<1>, G', the pinions A, B engaging, and the other pinions running freely. The clutches F, F' are disengaged by rotating the shaft L which, through the levers N and links N<2>, N', presses back one part of the sleeve E, carrying with it the clutch F. The shaft L may be made in two parts, connected by an Oldham or other coupling so that one part of the shaft and its support N<6> may move laterally, the sleeve N<5> sliding on the shaft D. The pinion A is thrown out of gear and the pinions A', B<1> come into action. On further motion of the sleeve E, projections e<4> engage with projections e<2> on the sleeve E', and the clutch F<1> is also drawn out of engagement. When the clutch F<2> is similarly withdrawn, the shaft C runs freely. The reverse motion is obtained by means of grooved friction pinions O<1>, O, Figs. 1 and 3, and idle wheels O<2>, O<3>. A shaft P, turned by a lever H, Fig. 4, operates a screw P<1> which presses forward a frame O<4> carrying the wheel O<2>, and, turning inside a boss P', draws back a frame, carrying the wheel O<3>, by means of a tube p<1>, sliding on a pin support p. As a modification, the clutch C<1> may be pressed laterally against a spring along the shaft C, with which it turns and plate springs between the other clutches cause successive disengagement of the pinions, the sleeves E, E', E' not being divided. As shown in Fig. 5, the clutches may be in two parts F<4>, F<5> and the pinions A, A', A' separate. As in this case, each pinion is moved laterally and to a greater distance than the succeeding smaller one, it must be of greater length in order to be always in gear with the pinion on the driven shaft. As shown in Fig. 6, the clutches F' may be mounted on sleeves E<7>, E<8>, E<9>, which, by means of feathers and grooves, may slide longitudinally, but turn with each other and the shaft C. The pinions A, A', A' rotate separately and are connected to external clutches F<6>, F<7>, F<8>. Instead of conical external clutch surfaces, cylindrical surfaces and expanding internal clutches may be used. Semi-cylindrical hollow clutch pieces F<10>, Fig. 10, are keyed at one end to the shaft C, a right and left handed screw F<25> passing through the other end. By means of a crank F<24> and a bar F<12> attached to one of the sliding sleeves E<7>, E<8>, E<9>, Fig. 6, the screw is rotated and the clutch piece F<10> forced against the external piece F<9>. The cylindrical surfaces F", Fig. 8, which are attached to the pinions, may be surrounded by a cylinder F<14>, through which screw-threaded studs F<15>, connected through cranks F<17> and arms F<18> to the sliding sleeves, pass and screw down the blocks F<16>. The controlling shafts L, P, Figs. 1 and 3, are operated, Fig. 4, by a lever H, which carries a catch H<1> moving in a quadrant J. If moved to the left from the position shown, the end H<2> of the lever moves freely in the slot K<1> in the pivoted plate K, and, by means of the pin H<3> and crank P<3>, turns the reversing-shaft P. If moved to the right from the position shown, the end H<2> swings the plate K and, through the link K<2> and crank L', turns the controlling-shaft L.