Indeed, the grand and only use of examples, is to sharpen the judgement. For as regards the correctness and precision of the insight of the understanding, examples are commonly injurious rather than otherwise, because, as casus in terminis they seldom adequately fulfil the conditions of the rule. Besides, they often weaken the power of our understanding to apprehend rules or laws in their universality, independently of particular circumstances of experience; and hence, accustom us to employ them more as formulae than as principles. Examples are thus the go-cart of the judgement, which he who is naturally deficient in that faculty cannot afford to dispense with.
"Go-cart" is a literal translation of Gängelwagen. It here means not a go-cart in the modern sense (which obviously wouldn't have existed at the time) but a baby-walker. Those in Kant's day weren't so fancy, but rigging a wheeled carriage so a baby could use it to 'walk' was a common thing even then. So we should really translate it as, "Examples are thus the baby-walker of judgment". Thus Kant's point is that examples are only of value (especially, although not exclusively, in moral matters) in helping us get by until we can think for ourselves - a very Kantian position very vividly expressed. Kant also uses the metaphor in "What Is Enlightenment?" in order to describe the self-imposed immaturity of whole societies: Enlightenment is the process of learning how to walk without the walker.