25,787. Monin, C. May 15, [date applied for under Patents Act, A.D, 1901]. Variable-speed gearing; pin-and-slot mechanism.- Relates to hypocycloidal arrangements for producing variable-speed motions. Fig. 5 shows the connection of two shafts on which the driven shaft 16 moves at a slower rate than the driving- shaft 14, and Fig. 11 shows the duplication of the connecting-mechanism each of the three parts being provided with pulleys 17, 18, 19. The shaft 14 carries a double pin disc 13, the pins of which engage in slots 10 of a disc 9. The disc 9 rotates in an eccentric cavity in the frame 12. The opposite face of the disc 9 has pins 11 which engage in grooves on a disc 15 attached to shaft 16. In a modified form, the disc 9 is in two portions separated by a pivotal axis and does not work in an eccentric cavity. The shape of the grooves in the slotted discs depends upon the ratio of the diameters of the pin disc and the slotted disc. In the form shown in Fig. 11, any one of the pulleys may be held stationary by a bracket or other means, and varying velocities in the same or opposite directions may then be obtained between the two free pulleys. Friction balls or rollers may be placed between the parts 9 and 13.