14 U. S. NATIONAL MUSEUM BULLETIN 2 04 



Rotating the rod tightens a cord running down the curved bar and 

 causes a brake shoe to bear against the single rear wheel mounted at 

 the lower end of the bar. This wheel is 2% inches in diameter and 

 has eight spokes. 



An axle is mounted at the bottom of the fork. On each end of the 

 axle is a wheel 7% inches in diameter and having 10 spokes. The 

 wheels are 8% inches apart. Cranks connect the axle and the wheel 

 hubs. 



Each front-wheel hub incorporates a pair of double-crown, ratchet 

 gears held together by a spring in the hub. Forward movement of 

 the axle drives the wheels, but when the cranking is halted and the 

 axle is stationary the ratchets open and the wheels coast. Also, as 

 stated before, the outer wheel slips when the machine is making a 

 sharp turn. Each intermittent opening of the ratchets would cause 

 the wheels to be forced slightly apart and would occasion considerable 

 wear of the teeth, as well as a clicking noise, deficiencies not found 

 in the Van Anden velocipede, with its pawl-and-ratchet device in the 

 hub of the front wheel. 



HAMMELMANN TRICYCLE, 1880 



U. S. N. M. No. 30925S ; original Patent Office model ; transferred from the U. S. 

 Patent Office ; photograph No. 784-A ; plate 12, a. 



Patent No. 225010 was issued on March 2, 1880, to Charles Hammel- 

 mann, of Buffalo, N. Y., for a velocipede. This model shows a tricycle 

 propelled by two foot-operated, spring-returned levers that rock 

 sector racks meshed with ratchet gears on the front-wheel axle. 



The model, measuring 8% inches long, Sy^ inches high, and 4% 

 inches wide, is constructed of metal, with the exception of the wooden 

 saddle. The frame consists of a curved bar at the rear, terminating 

 in a fork at its lower end, and a vertical fork at the front, this fork 

 pivoting in the steering head of the bar. A saddle is attached to the 

 curved bar by means of a spring. At the top of the front fork are 

 the handle bars. An axle at the bottom of tlie rear fork mounts two 

 wheels, each 21/8 inches in diameter and having six spokes. The 

 centers of the wide treads of these two wheels are 314 inches apart. 



The front wheel is 6 inches in diameter and has 10 spokes. Its 

 perimeter is grooved as if to mount a solid rubber tire, though it is 

 not known if a tire was mounted on this model. Mounted on each side 

 of the front- wheel hub are ratchet gears. The wheel and gears rotate 

 as one unit on the stationary front axle. 



Two foot-operated levers, spring-returned to their upper positions, 

 are pivoted at the lower ends of the front fork, one on each side of 

 the wheel. To each lever is attached a rack meshed with a gear that 

 is mounted free on the front axle and next to the ratchet eear on its 



