This cord is also like #6240 in that it goes from the transformer to the motor.  It has a rectifier built into the cord that changes the voltage from AC current to DC current.  It is mostly used on chairs with a Betadrive motor; many of those chairs have an AC transformer (it won’t have a battery backup); the Betadrive motor needs DC current, so that is the reason for the rectifier.

If you change transformers to the newer #6232 switchable AC/DC transformer, you will not need this type cord – you can use the #6240.