CATALOG OF THE MECHANICAL COLLECTIONS 7 



DOG-POWERED TREADMILL, 1878 



Plate 3, Figure 2 



U.S.N.M. no. 309199 ; original patent model ; transferred from the United States 

 Patent Office ; pliotograph no. 19978A. 



This model was submitted with the application for the patent 

 issued to F. K. Traxler, April 23, 1878, no. 202679. 



The treadmill represented consists of an endless track of wooden 

 cleats on a flexible belt, carried over two rollers held in a rigid frame. 

 The frame pivots about the shaft of the upper roller so that the lower 

 end of the frame may be raised or lowered to give any desired angle of 

 inclination to the track. A power take-off shaft is geared to the 

 shaft of the upper track roller. 



WARREN SPRING MOTOR, 1880 



U.S.N.M. no. 308835; original patent model, transferred from the United States 

 Patent Office ; not illustrated. 



This model was submitted with the application for the patent 

 issued to John Warren, of Detroit, Mich., April 20, 1880, no. 226813. 



The motor represented is of the class intended to operate light 

 machinery such as a phonograph but differs from most of the class 

 in that it employs a spiral spring instead of the usual coil spring. It 

 converts the rectilinear motion of the spring into rotary motion and 

 equalizes the varying tension of the spring. 



The free end of the spring carries a nut that engages in a spiral- 

 grooved motor shaft, which revolves at the axis of the spring. A 

 hand crank, worm, and worm wheel are used to compress the spring 

 by turning the shaft in the reverse direction. The power is taken 

 from a bevel gear on the shaft. A ball nut, which employs a ball to 

 follow in the groove of the shaft, is used because an ordinary nut 

 would not work in the groove of varying pitch. The varying pitch 

 is used to compensate for the varying tension of the spring. 



ADDITIONAL MODELS IN THE COLLECTION, NOT DESCRIBED 



Motor by foot power (treadle), Patent Office model. Patent no. 197759, Decem- 

 ber 4, 1877, issued to E. E. G. Bozerian. U.S.N.M. no. 308821. 



Hand and foot motor (treadle and levers). Patent Office model, Patent no. 

 229739, July 6, 1880, issued to D. W. Mott. U.S.N.M. no. 309200. 



Animal power (treadmill), Patent Office model. Patent no. 266844, October 31, 

 1882, issued to W. C. Knox. U.S.N.M. no. 309691. 



POWER FROM THE WIND 



It is now generally believed that boats wfre propelled by sails 

 on the Nile as early as 6000 B. C, but the first use of the wind to drive 

 machines and to do mechanical work came much later. Wind wheels^ 

 such as prayer wheels upon which were inscribed prayers, deemed 



