Can't remember the title of this book..?

It had something to do with "dinosaurs" and "shoelaces" in the title, but I can't seem to remember what it was called. I believe it had 3 (or 4) kids in it and a small dinosaur. They went through a portal. From what I remember, one of the kids' shoelace got stuck in the portal door and that's how the others knew they were there. Much thanks to anyone who can tell me the book title (: