Smooth transition dock system minimises dock shock and trailer drop

Arbon Equipment, through its parent company Rite-Hite Corporation, has launched an awareness campaign to call attention to ‘dock shock’ and ‘trailer drop’ - two issues that pose a serious health safety risk and adversely affect the productivity of virtually every facility with a loading dock.

Arbon has also marked a major milestone in the materials handling industry with the introduction of the Smooth Transition Dok system. The system is a range of products consisting of vehicle restraints and loading dock levellers that represent the first smooth transition system designed specifically to minimise problems with dock shock and trailer drop.

Dock shock and trailer drop describe the jarring and jolting that lift trucks and stand-up walkie operators encounter as they transfer materials within a facilities shipping/receiving/staging area and move in and out of semitrailers. According to Kyle Nelson, Rite-Hite Corporation Vice President New Business and Product Development, dock shock and trailer drop have existed since the original union between lift trucks and loading dock equipment.

However, he said recent trends dictated the need to address the issue: “For decades, companies have viewed lift truck jarring and jolting as something they had to live with. But, there is a growing concern worldwide about lift truck operator safety and the need to avoid chronic spinal-related injuries caused by vibration. “Additionally, companies are always looking for ways to make their dock a more productive and profitable working environment. Based on these factors, we made it our mission to be the first loading-dock-equipment company to isolate the problem and develop a solution.”

Identifying the issues

Rite-Hite’s research into dock shock and trailer drop dates back to 2001 when its customers began to raise concerns about the impact of jarring and jolting during the trailer loading and unloading processes.

Concerns ranged from product and loading dock equipment damage to safety issues. Safety concerns centred primarily on the fact that vibration results in musculoskeletal disorders of the neck and back, as well as the hand and arm. In addition to chronic injuries, it is known to cause operator fatigue.

To address vibration issues at the loading dock, many facility decision-makers have turned to lift truck manufacturers and suppliers. The forklift industry, in turn, responded with a number of innovations designed to minimise vibration. Yet serious problems associated with jarring and jolting remained largely unsolved, despite efforts by the forklift industry to address the issue and numerous studies that show it posed a chronic, long-term safety risk. The problem also gained the attention of the International Organization for Standardization (ISO), which issued various guidelines for vibration exposure levels, and the European Parliament and the Council of the European Union.

“As we began to explore the issue, we discovered that forklift manufacturers alone cannot solve the problem,” said Rite-Hite Corporation Vice President of Marketing Joe Manone. “This fact, combined with our customer-centric focus, drove us to take a closer look at the dynamics of the loading dock and take action.”

Discovering the solution

Rite-Hite’s research and analyses showed jarring occurs when a forklift (stand-up walkie or forklift) crosses between the warehouse floor and the trailer bed, due to the bumps and gaps that exist on traditional dock levellers. Rite-Hite uses the term ‘dock shock’ to describe the phenomena. Dock shock is a source of vibration which is known to pose a serious health safety risk. Whole body vibration and intermittent vibration are growing concerns worldwide.

Rite-Hite also analysed the trailer loading and unloading process, which showed that trailer beds move vertically, or ‘drop’, due to the weight of lift trucks travelling in and out of unstable trailers. The problem, which Rite-Hite describes as ‘trailer drop’, is often severe when trailers with air-ride suspension systems are involved. Trailer drop causes lift truck operators to experience significant jolts, which can lead to chronic back and neck injuries.

Rite-Hite engineers determined that the key modification in the company’s leveller design could minimise the jarring at key transition points. The company also looked to improve the design of vehicle restraints, which the company invented in the 1980s. Rite-Hite officials determined that a new restraint design would significantly minimise trailer drop.

Years of product development led to the Smooth Transition Dok System. The system includes the company’s line of hydraulic, mechanical and air-powered dock levellers that create a smooth transition between the warehouse floor and leveller. It also includes the ST-4100 Dok-Lok vehicle restraint, which is the only restraint of its kind that stabilises vertical trailer movement. The restraint also greatly minimises the potential for a number of catastrophic accidents.

Validating results

To validate the leveller’s ability to minimise dock shock, Rite-Hite tested its leveller line using the ISO2631-1 standard. The test results were measured against Directive 2002/44/EC of the European Parliament and Council of the European Union, which is the most stringent guideline available for vibration exposure in the workplace. The testing showed that Rite-Hite dock levellers reduce dock shock by 50% when compared with standard levellers under the same conditions.

Rite-Hite followed equally rigorous methodology to validate the ST-4100 vehicle restraint’s ability to minimise trailer drop. The tests, which involved the use of a linear velocity displacement transducer measurement device, showed the restraint can reduce trailer drop by as much as 300% when compared with standard vehicle restraints under the same conditions.

In addition to internal testing, Rite-Hite installed the Smooth Transition Dok System at numerous customer beta sites in a wide range of industries for nearly two years to access its level of performance in real-world applications.

“The hard data alone provides clear evidence that a smooth transition dock system greatly reduces dock shock and trailer drop and the problems they create,” said Nelson. “In addition, the qualitative data we’ve gathered from beta sites is very favourable, which is a solid indication of how this new technology fulfils a significant need in the marketplace.”

Arbon Equipment encourages facility decision-makers to take a closer look at their loading dock situation and learn more about dock shock and trailer drop.

These issues are gaining recognition and it’s the employer’s responsibility to control the environment where lift trucks operate. Given the importance of employee safety, as well as the adverse affect it can have on productivity and profitability, it’s important that decision-makers are aware of these issues, as well as a solution that allows them to design the problem out of the process.