There are times when closing a gate after yourself is nearly impossible, if your arms are full of shopping bags. If no one else is around, then you'll either have to put 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. Rig up a system using weights, gravity and the elegance of simplicity to build a self-closing garden gate.
Counter weight method
Drive a screw-hook into the top centre of the gate by turning it clockwise with a pair of pliers. This will serve as 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.
Clip the hook of the end of the fisherman's scale over the centre of the chain and pull the gate towards you. As you pull, note the number of kilograms of pull you have to exert to make the gate move to the closed position.
Tie the leather drawstring bag to the centre 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 pull taut, moving the bag of sand in the centre upwards. When the gate is released, the bag of sand in the middle of the chain pulls the centre of the chain downwards, 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 10 cm (4 inches) of chain past the pulley, while the gate is open and the chain is under tension. Cut the chain so that 10 cm (4 inches) of chain extends past the pulley.
Attach a weight, like a leather drawstring 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.
The centre-weighted closer can be adjusted for speed by varying the position of the weight from the centre of the chain. Moved closer to the jamb side of the gate, the gate will close faster. Moved closer to the hinge side, it will close more slowly.
While suitable for a garden gate, these methods are not suitable for pool enclosures.