This will split a string that has multiple spaces inside:

$str = " lazy fox         did   whatever      ";
$array_result  = preg_split("/[\s]+/", trim($str)); 

The resulting array contains the following tokens: lazy, fox, did, whatever. But you got to use the trim() function first, otherwise the array will contain an empty element at the end.

First I tried to use the explode() function, but it created array elements containing spaces. Preg_split() did the trick.