Considered posting this in off-topic, but crane games are kinda video gaming related, aren't they?
More examples and cabinet manuals that verify this can be found in the articles.
http://io9.com/5941335/the-dark-secret-of-arcade-crane-games-17-times-out-of-18-you-will-lose
http://www.quora.com/Arcade-Games/How-do-the-Claw-crane-arcade-game-machines-work
Looking to bone up on your arcade crane game strategy? (You know the game I'm talking about the one with the claw and the plush toys crammed all up inside it.) Well, we've got some sad news. It turns out strategy, at least when it comes to crane games, probably isn't as important as you think. Why? Because they're freaking rigged.
Another childhood pastime ruined.
Over on Quora, video game programmer Zack Baker claims that "most crane games are designed so the claw is randomly (and only once in many games) strong enough to let players win."
"Some even weaken in strength after a short time so players get close to victory only to see it slip from their grasp," he explains.
Here's an example of a crane with more elaborate settings:
There are settings for making the claw use its strong setting on most games, one game in a few, or almost never. There are further controls for the claw to grab in strong mode and then switch to weak mode anywhere from 2-9 seconds after grabbing. Finally, it can even be set to switch to weak mode 10-25 seconds from the start of the game, to put slowpokes at a disadvantage!
Panda Vending crane game manual
More examples and cabinet manuals that verify this can be found in the articles.
http://io9.com/5941335/the-dark-secret-of-arcade-crane-games-17-times-out-of-18-you-will-lose
http://www.quora.com/Arcade-Games/How-do-the-Claw-crane-arcade-game-machines-work