Choosing quick couplers

The tools used in the construction and demolition trade are wide-ranging and constantly improving. Sledgehammers evolved to handheld breakers, and shovels gave rise to excavator buckets. Whenever possible, manufacturers work to increase the productivity and safety of the tools contractors use every day.

Quick couplers are no different. These aftermarket excavator add-ons increase efficiency by eliminating the need to manually remove mounting pins, greatly reducing the time it takes for excavator operators to switch between attachments. Like all other tools, quick couplers are being constantly improved upon. When making a purchase decision, contractors should consider the application, hydraulic or mechanical configurations, safety features and additional performance features like tilting capabilities to get the most from their investment.

Convenience with a coupler

A quick coupler is an investment that adds convenience and flexibility to a fleet in just about every application. Without a coupler, switching between a bucket, ripper, rake, mechanical grabs, etc., can cost valuable time. Although couplers might make the machine heavier and slightly reduce the breakout force, they increase the speed and agility of attachment changeout. Considering traditional changeouts can take up to 20 minutes, a quick coupler can be transformational for decreasing the time it takes to tackle a job that requires different attachments.

If operators are switching out attachments every couple of days rather than every couple of hours, there may not be a need for a coupler. But if a contractor is using a variety of attachments throughout the day or wants to increase productivity with one machine on a site, a coupler is a must-have piece of equipment. Quick couplers can even reduce needed maintenance and cost, since operators may resist switching attachments when manual changeouts are required if he or she doesn’t want the hassle. However, utilizing the wrong attachment for the wrong work is a surefire way to increase wear.

A note on hydraulic vs mechanical couplers

Most manufacturers offer couplers in two configurations: hydraulic or mechanical. Each has its advantages and disadvantages related to size, cost and operating system.

A mechanical (or manual) coupler can offer lower cost, fewer components and a lighter overall weight. They’re typically the best choice if a job doesn’t require multiple attachment changes daily, or if price is the most critical consideration. Mechanical couplers have a similar purchase price to hydraulic couplers, but the requisite complex installation procedure often presents a large difference in fees.

With a mechanical coupler, however, convenience and safety can be compromised. Operators are required to physically leave the cab of the machine and use manual force to position the pin into place, causing the changeout process to take longer. It often involves two workers, and is an overall more difficult process. With a hydraulic coupler’s ease-of-use features, operators save time and effort by completing the process from inside the cab. This improves efficiency and safety.

Safety benefits of hydraulic couplers

Most coupler-related injuries are the result of an operator not properly securing the safety pin on semi-automatic or manual models. Numerous injuries, some resulting in fatalities, have occurred as a result of poor coupler connections and dropped buckets. According to a study conducted by the U.S. Occupational Health and Safety Administration (OSHA), there were 15 injury-related accidents between 1998 and 2005 in the U.S. involving the unanticipated release of excavator buckets from quick couplers on hydraulic excavators. Eight of those accidents resulted in fatalities.

Failure to properly engage and lock the coupler is likely the cause of accidents in most cases. According to OSHA, unintended coupler releases tend to happen because users may not be aware of changeout hazards, they fail to properly insert locking pins or they have insufficient training on installation and testing procedures. To decrease the likelihood of accidents, manufacturers developed solutions via hydraulic couplers to ensure proper engagement and minimize the possibility of injuries from operator error.

While a hydraulic coupler doesn’t eliminate all risk of dropped attachments, there are features that make them a safer option than mechanical couplers for preventing work site injuries.

To ensure operators engage the locking pin correctly, some systems feature red and green LED lights as well as a warning buzzer that let the user know whether or not the pairing was successful. This heightens operator awareness, helping them manage the system and prevent dangerous situations.

Since most serious accidents occur within the first five seconds of latching the attachment, some manufacturers have added features that make it virtually impossible for operators to unintentionally drop attachments.

One of these features is a wedge-locking principal that combats improperly locked pins. This requires the coupler to connect to the attachment in two separate places. This constantly applied working pressure continuously readjusts the wedge, keeping both pins firmly against the quick hitch and the attachment securely in place.

Advanced designs also offer a safety knuckle that securely latches instantly and automatically onto the first of two pins. This prevents the attachment from dropping, even if the operator forgets to complete the process. The safety knuckle works independently from the wedge that secures the second pin, preventing the release of the first pin even if the hydraulic system fails. Operators change attachments by first releasing the wedge, then placing the attachment in a secure position on the ground before releasing the safety knuckle.

For added safety, operators can look for a time-out feature offered by some manufacturers that automatically re-engages the safety knuckle. If the operator doesn’t fully detach the safety knuckle within the time-out window, the knuckle re-engages itself. This timing feature, which is customizable but usually occurs after 5 to 12 seconds, helps to prevent dangerous situations. Without this feature, there’s increased risk of the operator forgetting the attachment is unlocked and dropping it, either after lifting it off the ground or after unlocking it in the air.

Additional features and options

Simply adding a standard coupler to a fleet can save time and money, but there are additional features that can increase productivity even more.

Some hydraulic couplers and their paired attachments deliver 360 degrees of rotation. For added capacity, some manufacturers offer a universal joint that also tilts—often known as a tiltrotator. Couplers of this nature pair continuous rotation with tilting capabilities, making them even more efficient and productive than a standard coupler. They’re often built with a streamlined design, making them ideal in tight areas and applications like road construction, forestry, landscaping, utilities, railway and city snow removal.

Tiltrotators can cost a bit more and weigh more than a standard hydraulic coupler, so users should consider the features before selecting one.

Another aspect of couplers users should consider is whether or not the equipment is fully hydraulic. Some manufacturers have developed systems where up to five hydraulic circuits can be coupled comfortably and safely from the driver’s cab. A special locking system absorbs the resulting spreading forces between the valves without transferring them to the quick coupler. A fully hydraulic device allows for quick changes without extra manual effort. A system of this nature represents the next logical step for couplers, and the fully hydraulic direction of development will likely result in even greater safety standards.

Making an informed decision

As tools and technology evolve, contractors will increasingly find more options at their disposal. Efficiency and safety often go hand in hand, and they’re both equally important. Luckily, by analyzing applications, understanding the risks and optimizing the system for the company’s specific needs, contractors can find a quick coupler that can both enhance efficiency and improve safety.

This article originally appeared in the January/February issue of Construction & Demolition Recycling. Francois Martin is the general manager of Kinshofer North America. He can be contacted at f.martin@kinshofer.com.