You've got me thinking here! Did the robot when activated stretch it's arms out to the sides then crash them together in front? I remember this but it's years ago that's all I have! I'll do a search, I'm intrigued now.
memories! I recall a programme from 1968-ish involving 2 halves of a magic ring, when joined the ring summoned up a huge genie rather than a robot - that was "Shazzam"....
but I bet that's not what you're looking for, is it?