My patio tomato plant looks great its tall healthy looking, but it not producing any tomatoes. Why?

If your plant is tall and lush, and old enough, but not producing any blossoms it is probably getting too much nitrogen. It blossoms are appearing but not fruit, it may be a lack of pollination or the plant is under temporary stress. You can hand pollinate simply by gently taping the blossoms with your fingernail. That will loosen the pollen and distribute it around inside the flower. Blossom drop because of stress can be any number of things, such as too high or too low temperatures, too much or too little water, even air pollution.