Occur to me that constituents are bound to care (6,2,4)

I believe the answer is:

spring to mind

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'occur to me that constituents' is the definition.
I can't judge whether this definition defines the answer.

'bound to care' is the wordplay.
'bound' becomes 'spring' (both can mean to leap).
'care' becomes 'mind' (I've seen this in another clue).
'spring'+'to'+'mind'='SPRING TO MIND'

'are' is the link.

Can you help me to learn more?

(Another definition for spring to mind that I've seen is " Enter one's head".)

I've seen this clue in the Sydney Morning Herald.

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