Quick Coupler is a convenient hydraulic device that can easily connect a bucket to an excavator arm. It is becoming standard equipment for many manufacturers’ excavators and a popular aftermarket accessory. Couplers come in a variety of designs, all offering the same convenience: simple connections, multiple times allowing the operator to stay in the cab, faster switching times, and the ability to adapt to accessories from a variety of manufacturers.

But building safety experts have noticed that as the number of contractors using quick connectors has increased, so has the number of accidents involving the devices. Accidental bucket release is the most common event. What we saw was a worker in a trench box and the barrel fell off the connector. It happened so fast that he couldn’t avoid the falling bucket fast enough. Buckets trap him and sometimes kill him.

A study of more than 200 incidents involving the separation of buckets from fast couplers found that 98 percent were related to a lack of operator training or operator error. Operators are the last line of defense for safe operations.

Some couplers are configured to make it difficult for the operator to see if the connection is locked from the cab’s perspective. There are few visible signs of a locked connection. The only way the operator can safely determine whether the coupler is safe is to perform a “bucket test” every time the bucket is changed or turned on.

Bucket test for secure coupler connection

Place the bucket rod and bucket vertically on the side of the cab. Side testing provides better visibility.

Place the bottom of the barrel on the ground, teeth facing the cab.

Apply pressure on the barrel until the belly of the barrel is off the ground and the barrel rests on the teeth.

Continue pressing down until the excavator track is raised about 6 inches from the ground. For a better measure, push the revs up a bit.

If the bucket withstands the pressure and holds, the coupler locks into place.

Although some couplers have redundant locking characteristics, it is best practice to do bucket tests every time.

Not all the blame for coupler accidents falls on the operator’s shoulders. While the coupler itself may work properly, misinstallation can cause an accident. Sometimes contractors try to install couplers themselves or hire unqualified installers. If the coupler system for after-sales service is not installed correctly, perhaps to save a few dollars, the audio and visual alarm system may fail and the operator will not know there is a problem with the coupler.

If the arm of the excavator swings too fast and the hook connection is not locked, the bucket will be disconnected and driven into the nearby workers, equipment and structures.

Materials such as lifting and moving pipes need to connect the lifting chain to the lifting eye of the coupler rather than to the lifting eye which may be located on the back of the bucket. Before connecting the chain, remove the bucket from the coupling. This will reduce the excavator’s additional weight and provide better visibility for the operator.

Check the couplers to see if there are manual safety procedures, such as pin locking mechanisms, that require another person to insert the pin to complete the connection.

Use a separate secondary security system to keep buckets connected in the event of a primary system failure. This may be a lock/tag verification procedure as part of a routine system check of the device.

Keep couplers away from mud, debris and ice. The stop mechanism on some couplers only measures about an inch, and excess material may interfere with the correct connection procedure.

Keep the bucket close to the ground during all locking and unlocking operations.

Do not reverse the bucket so that it faces the excavator, as in the shovel position. The locking mechanism is broken. (If in doubt, consult your dealer.)

Keep your hands away from the connector. If a high-pressure hydraulic oil line forces leaking hydraulic oil into your skin, it can be fatal.

Do not modify the connection on the bucket or coupling, such as adding steel plates. Modification interferes with the locking mechanism.