The patent is United States Patent 5,067,932 to Edwards for
Dual-input infinite-speed integral motor and transmission device and the independent claim is:
1. A combination motor and transmission device comprising
first power input means for receiving a first input of electrical power,
second power input means for receiving a second input of electrical power, and
power conversion means for converting said electrical power of said first and second inputs for output, said power conversion means including a mechanical power transmission unit, said power transmission unit having two inputs for respectively receiving mechanical power corresponding to said first and second power inputs provided to said first and second power input means and an output for outputting the converted power as rotational mechanical power,
wherein the rotational speed of said output is continuously variable, and said power conversion means includes, for each of said first and second power inputs, a respective integral combination of a respective electric motor element and an element of said mechanical transmission unit, each said integral combination involving said two respective elements thereof being directly associated mechanically and geometrically with each other without substantial spacing or other elements including bearings and shafts therebetween.
and since each and every element in the
claim must be present in the
accused device - it looks like what my patent attorney calls a "picture claim" - and may not cover the Prius.
The real threat to hybrids was the patent suit on the metal-hydride batteries (in the early 1990's) - and that worked out.
This law suit on the batteries was GM's attempt to block the Prius - they bought the company that "invented" the modern metal hydride battery and then sued Toyota on their newly purchased metal hydride battery patents. That's how GM plays the game.