DOWN AT THE DOCK

BOB TREBILCOCK provides some advice on achieving safe and efficient warehouse dock operations.

Pallet loads and cases in and out. That's what so many people think tells the full story at receiving and shipping docks. But what gets overlooked so many times is what can be done to identify and meet the many ergonomic challenges that directly impact a dock's productivity.

To begin, there's more to designing an ergonomic dock than safely and efficiently loading trucks, according to Brent Tymensky, Vice President of Design Engineering for Fortna.

"You start with solutions based on how your product comes in," says Tymensky. "You have to look at everything from what kind of lorry you're going to receive, to whether the load is floor-loaded or unitized to what happens to it after it comes off the truck. Even the temperature inside the facility and the weather are important."

The solutions for the ergonomic dock fall into several categories that address each of those areas. Dock equipment, conveyors and lift tables are three prominent equipment types that effect dock ergonomics.

SAFETY AT THE DOOR

Maintaining the right temperature in a facility may not be the first thing that comes to mind when you think of dock safety. However, keeping out the cold, heat, rain, wind and snow ultimately makes for a more ergonomic dock, says Greg O'Neal, President, Air-locke Dock Seal.

Air-inflatable dock seals form a tight barrier around a lorry to keep the weather out and maintain the temperature inside the facility. That is true whether you're operating in ambient or refrigerated temperatures and it saves on energy costs.

"The dock seals not only keep rain and snow off the dock, they can generate a one-year payback on energy savings alone," says O'Neal.

The type of door may also play a role. One trend is fully impactable dock doors, says Mike Brittingham of SPX Dock Products. "Impactable doors are designed to pop out of the track if they're hit by a lift truck or lorry to minimize damage," he explains. "They can easily be put back in the track and are always accessible."

One of the biggest potential dock dangers is the premature exiting of lorries. That's when a driver pulls a lorry away from the dock while an operator is still on the lorry.

To prevent this danger, vehicle restraints hold the lorry in place. A variety of solutions - from simple blocks that go behind the lorry wheels to automated solutions that bolt to the cement dock and grip the rear impact guard of the lorry - are available.

An emerging restraint is a trapped key interlocking device. In these systems, a driver attaches a device to the emergency air line setting on the lorry brakes. A uniquely coded key is then inserted into a control panel that notifies an operator inside the facility that it's safe to open the dock door. When that happens, the key is locked in the control panel. The driver can't get the key to unlock the device from the air line to drive away until loading or unloading is finished and the operator inside the building puts the dock door back down.

An interlocking device forces a procedural process to prevent accidents since the lorry can't pull away until the dock ramp is inside the building.

BRIDGING THE GAP

The transition area from the warehouse onto the lorry is another important area of concern for both operator safety and ergonomics, according to Joe Manone, Vice President of Marketing for Rite-Hite Corp.

"Hitting the dock plate is the biggest bump a lift truck driver will experience during the day," says Manone. "There's also a shock we call 'dock shock' when the lorry drops from the weight of the lift truck." To reduce that bump and make the transition from the dock to the lorry as smooth as possible, manufacturers have redesigned dock levelers. Levelers may range in length from 1.8 to 4.6 meters, and the lip crown can be varied as well to capture the variety of lorry bed heights.

Some vehicle restraints can minimize the lorry drop. "For instance, a vehicle restraint can support the rear of the lorry," Manone says. "That eliminates the drop when you bring a lift truck onto the lorry. And since there's less vertical movement, you don't wear out your dock seals as fast."

Given the variety of levelers, restraints, dock seals and doors that might come into play at any one dock, one trend is to combine all of those functions onto one control panel.

This saves on installation because everything is integrated into one panel. Another benefit is that the ability to interlock the operations so that they happen in the sequence they should happen.

MANUAL HANDLING

Not all lorries, however, are unloaded with lift trucks. Cartons and product floor loaded onto lorries are still handled manually. For those facilities, portable conveyor systems can make loading and unloading both efficient and ergonomic, according to Les Paul of Caljan America.

"These conveyors can reach into a lorry, plus they are adjustable," says Paul. "That allows an operator to work at an ergonomic height regardless of whether the cartons are stacked to the ceiling or picked up off the floor."

Three types of conveyors are typically used at the dock:

• Extendable loader system - using manual roller conveyors, this is the simplest, and the angle of the conveyor can be adjusted up or down to allow gravity to move cartons.

• Fixed-length conveyor - also known as drive-out conveyor, uses power-driven belts for loading and unloading, but is not adjustable.

• Telescoping conveyor - beltdriven for loading and unloading and can automatically extend or retract like a telescope, which makes it a flexible, space-saving option on the dock, but also the most expensive.

THE STAGING AREA

Staging areas are also important areas of attention on the ergonomic dock. "If you have unitized loads, handling them is easy," according to Jim Galante, Director of Business Development for Southworth Products. "It's when products and pallets have to be manually handled that ergonomics is important." Typically, that happens if product has to be manually palletized or repalletized before loading or putaway.

One device used at the shipping dock is a pallet inverter that rotates a load 180 degrees. That allows an operator to easily remove a broken pallet or a leased pallet that has to be returned and replace it with another pallet for shipping or storage. With the new pallet in place, the load is simply rotated back to its original position.

Pallet position devices are used to keep a pallet in the correct ergonomic height as a load is palletized. Or, for working with tall loads, a facility may install a platform that allows an operator to work on the top of the load without reaching and twisting.

Regardless of the area of the dock, all of these solutions are designed to keep workers safe and ergonomic while optimizing the flow of goods on to and off of the over-the-road-truck.

Bob Trebilcock is Editor at Large, Modern Materials Handling (www.mmh.com)