570 



Popular Science Muiitlili/ 



Fig. 3. The spring on 

 rear wheel must be 

 wound up at each stroke 



Fig. lo has a ratk- 

 and-pinion ar- 

 rangement to take 

 advantage of this 

 heel pressure. So 

 also has the one 

 shown in Fig. 3, 

 but with greater 

 complication, 

 since a spring 

 on the rear 

 wheel must be 

 wound up at 

 each stroke. 

 The spring 

 keeps unwind- 

 ing and is thus 

 supposed to 



CUSHION 

 STRING 



All of the methods just mentioned are 

 open to the objection that tiiey use 

 fine gearing at a point where great stress 

 is imposed. Gear-teeth are likely to 

 shear off under such conditions and the 

 small l)earings to wear excessively. 

 However, the several mechanical move- 

 ments are decidedly interesting for their 

 ingenuity. The skate illustrated in 

 l-'ig. 4 uses a ratchet and pawl at the rear 

 hub but is operated by a long le\er reach- 

 ing to the center of the skate, to which 

 lever the foot-rest is attached. This 

 skate has large wheels and a low center 

 of gravity — both desirable features. A 

 handle just ahead of the foot-rest oper- 



Fig. 4. Large wheels, a low center of 

 gravity and a brake on the front wheel 



propel the ri<ler at a steady gait. In the 

 machine of Fig. 8 the rider's foot must in- 

 cline at an angle with each forward 

 stroke. The heel in descending makes a 

 pawl catch in a cog^vhecl and thus drives 

 the skate. 



It is impossible lo get more power 

 out of a machine than you put into it. 

 The inventions discussed fail to allow 

 for that fact. 



The skate shown in l"ig. 2 uses a .sort 

 of pantograi)h-ni()lion. In descending 

 ihe fool moves a lever downward. This 

 engages a ratchet arrangenunl inside 

 the hub and causes the rear wheel to 

 revolve, thus driving the skater forward 

 at a proportionate rate of speed. 



SOf£ fLATE 



Fig. 5. A single large bicycle-like wheel 

 to be fastened to each of the rider's legs 



ates a brake on 

 the front wheel 

 through the meil- 

 ium of a connect- 

 ing rope. 



Other skates are 

 difficult to classi- 

 fv. For instance 

 there is the one 

 shown in l-'ig. 9, 

 a kind of me- 

 chanical centi- 

 pede. It has 

 nine rollers per 

 skate, arrang- 

 ed in single 

 and double 

 rows, the ob- 

 ject of the sin- 

 gle rows being 

 to give more 

 of knife-edge 



Fig. 6. Skate propclcd 

 by taking strokes in 

 the usual simple way 



