394 
TEE MECHANISM OF BICYCLES. 
The Bantam, Mechanism . 
Diagram “ E.” pact. There are some two ot three 
varieties but the principle in every 
instance is very similar. There is 
an annular wheel attached to the 
front fork in such a way that it can¬ 
not move ; inside this wheel is a 
spur wheel which is attached to the 
hub of the front or driving wheel, 
gearing into both of these wheels 
and fitting in between them, are 
four small pinions placed equidistant 
from each other, free to revolve 
on their axles, the latter fit into a 
flange to which are also keyed the 
two pedals and the spindle joining 
them. It will thus be seen that 
the motion of the driving wheel is 
obtained by turning the pedals and 
consequently making the four pinions run round the fixed annular 
wheel. The figure shews the arrangement for a gear of 66 with a 
driving gear of 24 inches (a feature of the machines being their small 
wheels). 
The small size of the wheel though causing a diminution in the 
weight increases the rolling resistance and also increases the shock 
and vibration caused by contact with loose stones in the road. 
The chain friction is no doubt avoided, but in its place we have the 
friction of the axles carrying the pinions and they are not on ball bear¬ 
ings. 
I have heard rumours that the Bantam machine has a tendency to 
kick going down hill, a vice to which the old high machine was very 
much addicted. 
The Crypto machines are worked on a similar principle, the wheels 
being from 32" to 36" in diameter. 
The Bantam machines can now, if required, be procured with wheels 
26" in diameter. 
Other chainless machines are those fitted with bevel gearing, the 
best known being the ^Acatene.” In the place of the sprocket 
wheels there are two bevel wheels, each of them gearing into 
another bevel wheel attached at either end of a hollow shaft which 
rotates on ball bearings round the back stay of the machine. Thus the 
motion is conveyed from the pedal to the driving wheel. See 
diagram F. 
The back wheel does not require to be adjustable but is fixed to the 
fork by screws. 
In some other makes of bevel gears, small rollers have been substi¬ 
tuted for the ordinary teeth on one of each pair of wheels in gear, but 
it is an open question whether any friction is saved thereby. 
The neat appearance of the Acatene is apparent to all, but the draw¬ 
back to all bevel gearing appears to lie in the fact that in order to 
