There are times when closing a gate after yourself is well-nigh impossible, if your arms are full of shopping bags. If no one else is around, then you'll either have to set the bags down on the ground and close the gate, or take the bags in and leave the gate open until you can return to tend to it. This problem vexed the earliest settlers in towns that became the cities of the eastern United States, and their solutions followed later settlers westward. Both systems used weights, gravity and the elegance of simplicity.
Center Weight Method
Drive a screw-hook into the top center of the gate by turning it clockwise with a pair of pliers. This will serve one of two anchors for the closing mechanism.
Drive a second screw-hook into the inside of the gate post on the hinge side of the gate. This screw-hook will act as the second anchor and should be equal in its distance above the ground to the screw-hook on the gate.
Attach one end of a lightweight chain to the screw-hook on the gate post, and the other end of the chain to the screw-hook on the gate.
Set the hook of the end of the fisherman's scale over center of the chain and pull the gate toward you. As you pull, note the number of pounds of pull you have to exert to make the gate move to the closed position.
Tie the leather drawstring bag to the center of the chain. Fill the bag with sand, until the bag is equal in weight to the amount of pull required to make the gate move to the closed position. When the gate is opened, the chain will be pulled taut, pulling the bag of sand in the center, upward. When the gate is released, the bag of sand in the middle of the chain will pull the center of the chain downward, pulling the gate closed.
Gravity Pulley Method
Drive a screw-hook into the top of the jamb side (the side farthest from the hinges) of the gate with a pair of pliers.
Drive a screw-in pulley to the inside of the gate post on the hinge side of the gate. The pulley should be equal in height above the ground to the screw hook on the jamb side of the gate.
Attach a chain to the screw-hook on the gate. Thread the chain through the screw-in pulley.
Open the gate until it is at a 90-degree angle to the fence, while restraining the movement of the chain through the screw-in pulley. Measure off four inches of chain past the pulley, while the gate is open and the chain is under tension. Cut the chain so that four inches of chain extends past the pulley.
Attach a weight, like a leather draw-string bag of sand, to the chain. The weight must be heavy enough to pull the gate closed when the gate is released: The weight drops, pulling the chain through the pulley; as it does so, the end of the chain attached to the gate pulls the gate closed.