The 9V Electric System
1990 EU Technic catalog
7 new sets were released, including no less than 3 sets featuring the new 9V electric system. The 8064 Motorized set replaced the 8054 set after only 1 year. 3 of the new model sets featured the new engine elements and were categorized, at least in some of the catalogs, as the 'Rally' sub-theme.
The 9V electrics:
The new 9V electric system represented the first change in Lego's electric elements since the introduction of the 4.5V system in 1966 or the 12V train system in 1969. The system replaced every previous electric element with a new design. Although originally released in the Technic theme, Lego soon standardized their entire product range to this new 9V system.
US patent 4,743,202
The conducting plate:
For some time Lego had been working on a building element that could be attached in the typical fashion and still conduct current, yet not be easily short-circuited. Several patents from this time described a typical Lego plate with 2 isolated metal inserts that were exposed underneath as well as on top through cutouts in the sides of the studs. The exposed metal on the studs was arranged in a mirror image on either side of the plate so that when 2 plates were attached they could conduct current but could not be short-circuited. In production the plates had a simplified metal insert that allowed easier connections.
US patent D314,993
The engine cylinder:
A series of new highly-specialized engine elements was also released in 1990. This new system included a cylinder block, pistons, piston rods and crankshaft elements. The result was much more realistic and properly scaled engines and represented another addition to a now rapidly growing collection of highly specific vehicle elements.
US patent 4,461,116
The friction connector:
Lego would often change the design of elements and the new friction connector was a prominent example. The new connector had slits in the middle and at both ends, making it easier to remove than the original. The patent shows an elastic cylindrical plug with an annular central collar. When the connector was inserted into a beam hole the center slit would compress and the ends of the connector would expand, causing a relatively permanent connection. It is interesting to note that the new friction connector was produced 8 years after the original patent was filed in 1982.
The Control Center
8094 Control Center:
Dacta, the educational division of Lego, had been marketing several computer-controlled devices since the mid 1980s, but the 8094 Control Center was the first retail computerized Lego set.
The Control Center had 3 9V outputs for 3 motors. 1 motor was directly controlled by 2 buttons that ran the it foreword or backward. The other 2 motors were controlled simultaneously by a 4-position Control pad that had 8 different combinations, resulting in 2-axis control. 2 separate series of keystroke sequences could be recorded then played back as a 'program'.
The 8094 set included instructions for several models, including a programmable plotter and 3-axis robotic arm.
8064 Motorized Universal Set
8094 Control Center
8720 9V Power Pack
8825 Night Chopper
8830 Moon Buggy
8840 Rally Shock and Roll Racer
8850 Rally Off-Roader