The next transmission is of almost the same in function but of much different in structure as compared with the preceding one. The conical surface on the gear we have mentioned in the preceding transmission is eliminated and’ a disc having a conical surface in this structure is attached to the gear on this transmission. The cones are replaced by new rings. Right and left rims are connected with each other by three synchronizer pins, of which stepped centers passing through the sleeve are very loose fit to the holes in the sleeve. Each of three guide pins inserted in the sleeve is locked at its notched center portion with a spring-loaded detent ball, and moves against either of. the left or right ring according to the movement of the sleeve.
When the sleeve is pushed toward a gear, the ring is forced to contact with the disc. Two surfaces in contact produce a friction force as a slip wrists between the two surfaces rotating at different peripheral velocities. Under the effect of this friction force, the ring tends to follow the rotation of the disc, and this tendency makes each of the synchronizer pins come into eccentric contact with the hole, through which the pin is located in the sleeve, to give a torque to the sleeve in that direction.
As long as the said friction force exists, the sleeve cannot be allowed to reach the gear to engage with, because the large diameter of the stepped pins kept in an eccentric alignment with the pin holes in the sleeve\restrains the sleeve from further movement,
When the equalization of peripheral velocities of the ring and the disc is reached under the influence of the friction force abovementioned, the friction force ceases to exist. This makes the synchronizer pins back to the proper alignment with the pin holes, thus allowing the pin holes in the sleeve to easily overcome the restraint at the large diameter of the stepped pins. In result smooth engagement can be achieved between the sleeve and the gear.