Shifting Gears Automatically 



It is done by electricity, a mere pres- 

 sure of a button effecting the change 



Interior mechanism of 

 the car. The current 

 to operate the shifter 

 is taken from the bat- 

 tery of the starting 

 and lighting system 



There are four buttons, 

 one for each speed- 

 change gear. As these 

 are pushed the gears 

 are moved into mesh 

 by magnetic attraction 



ONE of the electric gear-shifters now on 

 the market, the use of which enables 

 the gears to be changed by the mere 

 pressure on a button, is oper- 

 ated on the principle of electro- 

 magnetism in which solenoids 

 are used. The solenoid is 

 similar in many respects to 

 the common horseshoe mag- 

 net except that whereas the 

 energy of the horseshoe mag- 

 net is permanent and does not 

 vary, the solenoid exerts its 

 power only when electric cur- 

 rent is passing through its 

 coil. As shown in the accom- 

 panying sketch, the simple 

 solenoid consists of a spool 

 around which is wound a coil 

 of wire, the ends of which are 

 attached to some current 

 source. A metal rod inserted 

 within the hole of the spool 

 will move to a position where 

 both ends project equal dis- 



tances from 



is passed th 



This 



__ the left, moymc fear to the left If ( 

 throufh solenoid No. 2, rod and (ear will ir 



A simple solenoid with 

 rod, one of which is 

 provided for each of 

 the change-speed gears 



the ends of the spool if current 



rough the coil of wire. 



the principle of the electro- 

 magnetic gear shift, one sole- 

 noid being provided for each 

 of the change-speed gears in 

 the transmission. A rod with 

 an arm carrying the gear is 

 inserted in the solenoid. Cur- 

 rent passed through the sole- 

 noid causes the rod and the 

 gear to move back or forth, in 

 or out of mesh with other 

 gears which transmit the pow- 

 er to the driving wheels. In 

 the ordinary gear set with 

 three speeds forward and one 

 reverse, four speeds in all, 

 four solenoids are used. Thesei 

 are arranged in two sets 

 two each as shown at th 

 bottom of the accompanying 

 sketches. Steel shafts carry- 

 ing gears on arms are placed 

 inside of the solenoids, and asj 



524 



