Quote:
Better hooks won't do you any good unless the springs that clamp the handle down are also stronger.

Untrue. Currently, the hooks are just angled to catch the slot in the sled. If they were engineered to be curved on the interior, creating a concave slot for the sled's sheet metal to catch in, they would be much more resistant to sliding out in the manner described.

When the hooks push back, they also move downward. If you can prevent that downward motion, you can prevent the backward motion, too.

Doing this is likely to require some headroom on top of the sled, but that's probably not an issue.
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Bitt Faulk