Home at last after our fun five-day Victoria vacation - we've apologized to the cat for being away, he's reluctantly accepted our apology, we've unpacked, made dinner, done some laundry - time to get serious with the Major Matt Mason Space Crawler that I stumbled across at Cherry Bomb Toys.
The rotating leg/wheel mechanism may not be unique, but it should be - as it turns out, Mattel filed a patent for the whole thing in 1970 under US Patent #3529479A. (Funny that I've never found any reference to this elsewhere.) To be fair, the patent also defines the complicated gearing mechanism that makes the whole thing work, and refers to "wheel substitutes" rather than attempting to define that part of the toy.
The battery contacts are a bit corroded, which, sadly, is the most common cause of death for toys that have been stored with the batteries in place. Over time the cells eventually self-deplete, after which pressure from gas buildup splits the casing and the subsequent leakage destroys the working parts.
However, early days - the upper and lower contacts aren't particularly clean, but it appears to be primarily just surface buildup, let's hope for the best.
The next day, I pick up a set of D batteries* on the way home, and after dinner return to the fight. I gently open the power compartment (pro tip: always be careful when dealing with any 58 year old toy that uses compressed plastic for hinges) and, after taking a moment to decipher the insertion directions, pop in the batteries.
The mechanical power switch is the simplest thing in the world, just a plastic plate that rotates in and out of the gap between the battery and the contact. I close the compartment, move the switch - and nothing. I test the drive/winch control just in case, still nothing. I'm a bit disappointed, but again, early days.
A search through my toolbox produces a torn sheet of emery paper, and I use a piece of it to carefully scrape away at the upper battery contacts until I see bare metal instead of corrosion. The lower contacts are less accessible, so I decide to do a work-in-progress test before building some kind of tool to get at them.
Batteries in again, and I move the switch - success! The motor grinds into action - "grinds" being the appropriate term, it's a bit loud - and the paired legs begin to rotate. I test the winch control, and it works like a charm, both forward and backward.
However, when I carefully place the crawler on the floor, only one wheel - leg? - rotates, the other one does nothing. There's a plastic friction mechanism that acts as a sort of primitive differential release, so that if either wheel is blocked or jammed, the motor can continue to operate. The mechanism for the right wheel is too loose to engage, and as such there isn't enough friction for the drive unit to move it.
I test it with some tape, and once the right wheel is secured to the friction tab, both wheels rotate to drive the crawler noisily across the hardwood floor - to Jaq the Cat's initial dismay but eventual indifference.
I'm a bit foolishly pleased by the whole thing - it just adds to the serendipitous nature of this purchase that the crawler actually still works after so many years. It's a bit jerky, but you know, as the saying goes, it's not that the bear dances well, it's that it dances at all.
- Sid
* Yes, surprise, D batteries - am I alone in thinking that everything is AA these days?
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