Now receiving no salary, Frank worked hurriedly on the transmission throughout late November, December, and the first two weeks of January. First discarding the old friction drum and shaft, and the shipper-fork carriage, he bolted a rawhide bevel gear to the lower surface of the flywheel. This turns two bevel gears, in opposite directions, on a countershaft directly underneath, approximately in the position of the old jackshaft. The right bevel gear is secured to the main countershaft on which two clutches are mounted, one on each side of the crankshaft. On a sleeve turning freely around the countershaft is mounted the reverse bevel gear and clutch. Three free-running clutch drums, the right one carrying the high-speed gear, the two on the left carrying the combination low speed and reverse gear between them, complete the countershaft assembly. The clutch assemblies are of Frank Duryea's design, having internal arms, expanding outward to press leather-faced shoes against the inner surface of the drum, thus securing the drum and its gear to the shaft. Behind this machinery is the jackshaft with its small differential on the right, two laminated rawhide gears[33] meshing with the iron gears of the countershaft, and the internal-gear sprockets hanging on the small pinions at either end. A sliding cam bar, mounted nearly in the position of the former shipper-fork carriage, is operated by the vertical movement of the tiller handle to engage any one of the three clutches. With the tiller depressed, the vehicle is in reverse. Elevating it slightly puts it into low gear, and raising it still higher runs the machine at its highest speed.
| Figure 25.—Half of Jackshaft, showing rawhide gears, double shrouded pinion and half of the Columbia differential. | Figure 26.—Half of Jackshaft showing double-shrouded pinion and half of the Columbia differential. |
Figure 27.—Cam bar in foreground, operated by tiller,
actuates the various clutches of the transmission. The overflow gasoline tank
with the hand pump can be seen in the rear.
Figure 28.—A drawing and the first page of the specifications of the first patent issued to C. E. Duryea.
It can be readily seen that this drawing was not made after the plan of the first vehicle.