Dancerina
Dancerina is a Mattel ballerina that dances (spins around and toe steps) when the mechanism in her crown is operated. She was released in 1968. There are several YouTube videos that demonstrate her movements. Dancerella, another Mattel doll, came out later (1969) and has a similar dancing mechanism. A Baby Dancerina was released in 1972.
The problem with this doll is that the ball joints in the shoulder are weak. Both arms broke off. Cyanoacrylate was used to reattach the broken pivots and then the arms were reattached. The battery compartment was stained and the contacts showed signs of corrosion from batteries that leaked from being left in the doll for an extended period of time. The fracture on the leg could be due to bending the leg in ways it wasn't meant to move or the natural shrinkage of hard plastic as it ages.
Patent: US 3616570
The problem with this doll is that the ball joints in the shoulder are weak. Both arms broke off. Cyanoacrylate was used to reattach the broken pivots and then the arms were reattached. The battery compartment was stained and the contacts showed signs of corrosion from batteries that leaked from being left in the doll for an extended period of time. The fracture on the leg could be due to bending the leg in ways it wasn't meant to move or the natural shrinkage of hard plastic as it ages.
Patent: US 3616570