Does an oath of divorce take effect for not going to pick up one's wife from her father's house, if her paternal grandfather, or the husband's paternal grandfather, sends her from her paternal grandfather's house where she is temporarily residing?

As long as you did not go to bring your wife back, but rather she returned with your grandfather, you have fulfilled your oath and not broken it, and your divorce has not occurred.

We caution you that the lawful oath is to swear by Allah Almighty. As for swearing by divorce, it is among the oaths of the dissolute, and it may lead to dire consequences. Therefore, one should beware of it.