A New Ball Differential for Automobiles 



It will enable a car to get out of 

 a hole when only one wheel grips 



ANEW differential for automobiles has 

 just been put on the market which 

 differs from all previous types in that 

 the differentiation is secured not through 

 gears but through the friction of steel balls 

 running in grooves. It 

 has an advantage 

 over former de.- 

 signs in that 

 while the power 

 of the motor is 

 differentiated 

 between the 

 two wheels in 

 the usual manner 

 for corner turn- 

 ing, it will still 

 The center plate is allow a car to pull 



of chromo-nickel q^^. ^f ^ h^ig ^^^^ 



steel into which are . 111 



fitted steel balls only one wheel has 

 traction. 

 As shown in the 

 accompanying views, 

 the device con- 

 sists of a con- 

 V e n t i o n a 1 

 different ial 

 casing at the 

 center of which 

 is a plate carry- 

 ing eight steel 

 balls arranged 

 on two concen- 

 tric circles. 

 These balls 

 move in cres- 

 cent-shaped 

 grooves in two 



The power shaft 

 of the automobile 

 turns the ball-plate 



The differential in position 

 and the relation of the work- 

 ing parts to each other 



disks, one on each side of the plate. 

 The disks carry the ends of the 

 axle shafts. Each groove is deep 

 and wide at its middle, tapering 

 off to points at the ends. The 

 deepest part of the groove and 

 the thickness of the center plate 

 are each one-half the diameter 

 of the balls. When any one ball 

 is at the deepest part of the 

 groove on one disk, it is at the end 

 of the corresponding groove on the 

 other. 



The transmission of the motor 

 power through the large differential 



The balls move 

 in crescent- 

 shaped grooves 

 in two disks 



ring gear to the plate carrying the balls 

 creates a thrust which tends to force the 

 disks apart, causing them to press against 

 grooved washers in the ends of the casing. 

 When the car is running ahead, the plate 

 and the disks revolve 

 as one piece, like 

 any differential, 

 the thrust ex- 

 erted by each 

 disk and the 

 torque on each 

 wheel being 

 equal. In turn- 

 ing a corner, the 

 power delivered 

 to the wheels is un- 

 equal, due to the 

 tendency of one 

 wheel to turn faster 

 than the other. This permits the balls to 

 revolve from the grooves of 

 one disk into those of the 

 other, causing one 

 disk to move faster 

 than the 

 other and 

 similarly 

 allowing 

 the outer 

 wheel to 

 turn faster 

 than the 

 inner. I f 

 one wheel is 

 spinning, 

 the friction 

 induced by 

 the disks 

 arrests the 

 spinning wheel and converts its 

 motion to torque on the stationary 

 one, the spreading of the disks 

 acting as a brake on the spinning 

 wheel because only on that side 

 is there relative motion be- 

 tween the disk and its case. As it 

 is the inner wheel which usually slips 

 when an automobile turns around 

 a corner, the action of the new ball 

 differential is considered an improve- 

 ment over the old type bevel gear. 

 It is being used on a number of cars. 



The gearless dif- 

 ferential which 

 gives a positive 

 pull at all times 



Q«n 



