(AWEP) are used to provide significant ergonomic benefits by positioning the worker to the job.

There are many defined workstations in manufacturing facilities with points of human interaction at an elevation above the plant floor, requiring that the operator be positioned on a raised platform. Often times, these platforms are makeshift and can present safety hazards.

It is also common for the plant maintenance department to fabricate non-adjusting platforms configured for the "average employee." These fixed-height platforms do not correctly accommodate the 5'-4" employee and the 6'-4" employee.

Multiple-shift operations, where three different operators interact with the same process machine in a 24-hour period, complicate the accommodation issue. Job rotation with operators changing jobs every couple of hours adds even more challenges to the workplace ergonomics issue. Job rotation may spread the risk of worker injury over a larger worker population, but is down not eliminate the risk. Modifying the characteristics of a workstation to reduce the number of bad choices an operator can make for providing operator control over the physical characteristics of workstation are proactive methods for addressing in-plant ergonomics issues.

AWEPs provide each operator with the ability to control their own position in relation to the task at hand, and position the task so that the operator can gain a biomechanical advantage over the task.

AWEPs are typically mechanically-driven devices that are manually adjusted. Platform sizes vary from 2' x 3' one-person units to larger runways parallel to assembly lines. Heights start as low as 2 ¼" above the shop floor. Most units have 12 inches of vertical adjustment. AWEPs can be pit-mounted, if necessary. Capacities are typically 400 lbs. Powered AWEPs can be activated using electricity or shop air.

These overhead devices provide and perform functions similar to overhead hoists in that they can lift and lower a load. The balancer configurations and suspensions are similar to a hoist.

The balancer functions differently from a hoist. The functional difference is indicated in the name "balancer." A balancer balances the load in a near weightless condition during the lifting operation.

This feature allows the operator to maneuver the load easily. Balancers are often used for awkward and/or rapid load movements. Balancers can also be used to suspend equipment which is used in repetitive operation. A variety of control options are available. A very broad range of load handling devices (end effectors) can expand this product's versatility. Balancers are typically supported on small jibs, light monorail systems or tubular track monorail systems, or as part of a workstation.

Both air-powered and electronically driven balancers are commonly available. Balancers can weigh up to approximately 100 lbs. and have approximate lifting capacities of 500 lbs.

Containers, boxes and baskets are widely used to store and transport parts and products. Although they are efficient, loading and unloading them requires motions that can be unsafe for workers. Regardless of how light the stored parts are, workers must repetitively bend, stoop, reach and lift as they work their way to the bottom of these containers.

To make the process safer and more productive, the container should be moved up to toward the worker as it is unloaded. Proper positioning can eliminate the need for bending, stretching, reaching and unnecessary lifting.

Pictured are portable tilters which allow containers to be picked up, moved into position, and tilted for easy access. There are similar stationary models which allow containers to be directly placed on the tilter by hand pallet trucks or fork trucks. In addition, there are floor height pivot point devices and tilters that mount on lift tables and other bases.

There are nearly as many tilter designs as there are container styles, and application information must be carefully considered before equipment selection. Special attention should be given to all container dimensions and the weight and configuration of the parts.

Industrial scissors lifts are used in a wide variety of ergonomic applications where bottom-up movement is required. They are used in industries such as manufacturing, assembly, warehousing, distribution, sheet feeding, and printing, just to name a few.

Generally, scissors lifts, or lift tables (as they are sometimes called), may be used to position material so operators do not have to lift excessive loads, lift repetitively, or bend to do their jobs. These tables can include variations to facilitate horizontal movement on the deck such as conveyors or ball transfers. In addition, portability options for the base allow the complete unit to be moveable. Tilting devices can be added so loads can be positioned both vertically and angularly.

Scissors lifts can be adapted to any plant situation by choosing from different power options. For example, lifts can be powered with electric or air-powered hydraulic pump units, pneumatic lift systems or full mechanical lift systems.

Scissors lifts can be installed in any number of ways to meet specific requirements. Generally, they will be surface mounted or pit mounted. They can be either fixed in position or moveable in either case.

A manipulator has a mechanical arm which can move a load horizontally as well as vertically. Manipulators, unlike the hoist or balancer, can provide more than vertical lifting and lowering. Manipulators combine mechanical arms, cylinders/motors and application-specific load handling devices. The devices are often called end effectors. The devices are generally dedicated to a single product.Manipulators can be floor-mounted, column-mounted, mounted overhead on a rail system or attached to a ceiling.

The machines are generally operator-controlled at or near the load control devices. The operator can manually manipulate the load in the pick, move and place functions. The load is in a near weightless condition similar to the balancer. Since the manipulator is often used to "reach" in the pick, move and place cycle, it is slower and may require more operator effort than a balancer.

Both products provide a wide range of ergonomic benefits. Balancers and manipulators provide a near weightless lifting situation, easy reach and orientation. They provide easy handling with difficult, rapid, repetitive or awkward applications.

Manipulators and balancers can be designed for specific application. Before choosing a piece of equipment, you should consider its intended use. Either piece of equipment can adapt to different load sizes and shapes. Lift and lower distances are generally limited to the operator's reach.

Throughout industry, shipping and storing goods on pallets is a methodology for transferring inventory. This type of unit load handling can create numerous materials handling challenges. Most of these difficulties are associated with restacking the pallet load and many can be handled by mechanically inverting the entire load instead.

Broken pallets can be easily removed and replaced. Crushed, damaged, or broken containers or bags can be pulled from the bottom of stacked loads by simply rotating the entire stack. Outgoing loads can be readily transferred from wood pallets to skids or slipsheets used for shipment. Incoming loads can be just as quickly transferred to permanent pallets used in racking systems or to special pallets for food handling and similar applications.

In operation, a pallet truck or fork truck is used to place palletized loads in the rotator. The pallet to which the load is to be transferred is placed on top of the stack. The rotator grips the load and rotates it 180 degrees, transferring the load from one pallet to the other.

Manually propelled lift trucks, commonly called stackers, can be extremely versatile group of ergonomic assist products. They are designed to efficiently transport work from on e work station to another, as well as, for elevating loads to comfortable ergonomic work heights.

Stackers are available with platforms, adjustable forks or fixed forks. Capacities range from 250 lbs. to 3,000 lbs., and load centers to 24", to handle load sizes up to 48" square.

Fork model stackers off vertical level from floor level (5" for platform models) to 4', 5', 6', 8', 10' and 12' in lift height within a very small foot print. However, most ergonomic applications require only lower lift height models.

Hydraulics is the most frequently used method for lifting, although wire rope and winch are used with some lift weight manual types. Battery lifting power is most frequently used, but manual, AC electric, and air power models are available. A control lever is usually located at fingertip level on a control panel, but hand pendants and foot controls are also available.

Stackers effectively move, raise, and position wire baskets, tote boxes, crates, skids and pallets to proper ergonomic work levels for maximum efficiency, productivity, and worker safety. They are also available with numerous attachments and accessories to transport and position special work loads such as barrels, coils, rolls, etc.

Vacuum tube lifters are ergonomically designed to reduce back strain, injuries and accidents therefore reducing or eliminating workers compensation claims. When using a lifter on a daily basis, worker fatigue should be greatly reduced and productivity increased. The lifter impact on the work place, because of its versatility, should help reduce absenteeism and downtime. Using the vacuum lifter can accomplish many repetitive lifting tasks ergonomically, quickly and skillfully, without delay.

Vacuum tube lifters have a wide range of capacities from as little as 40 pounds up to 1,000 pounds. These units are powered by anywhere from 3.5 h.p. up to 7.5 h.p. regenerative blower.

Most vacuum lifters offer many standard vacuum heads. These heads usually twist or snap on or off to change one head to another and can be done in a matter of seconds. There are a variety of standard vacuum heads designed for specific applications from situations involving narrow spaces with little room to maneuver, to load destinations which are higher than the operator's head, loads form sacks, to cartons, to 55 gallon drums, or large wood or metal sheets. Other standard heads enable the handling of different package shapes and surface types. There are even heads which can enable the operator to reorient cargo vertically or horizontally, with integral vacuum pump or pneumatic assist devices.

Workstations meeting criteria relating to ergonomics should be designed to include the following:· Vertical adjustment of the work surface. The surface should allow for persons of various heights and physiques to adjust the height to meet their physical characteristics. This would be especially true in multiple shift applications.

• Vertical height adjustment is also necessary as manufacturing or assembly work changes. The height required to assemble or manufacture should change as the product or subassembly changes.
• Vertical adjustments should compensate for the size of the component.

Considerations for a well designed workstation:

1. Everything the worker needs for the task should be available without stretching or reaching and should be easy to handle.
   
2. Items being handled should not require the hands to work at a level which averages more than 6' above the work surface.
   
3. Items in excess of 10 pounds should use a mechanical assist - nothing needs to be lifted from the floor.
   
4. The ideal work area should be semicircular around the worker.
   
5. The work surface should be at elbow height or slightly below it, so the forearm is horizontal or slightly slanted down.
   
6. Optimum height of work surface should be: For writing or light assembly - 27.5" to 31"; For heavier manual work - range of 26" to 28.5"
   
7. Work area should be well lighted with a glare eliminating system.

Enclosed track workstation cranes are ergonomically designed for lighter loads, from 150 lbs. to 4,000 lbs. capacities. Horizontal movement is usually push, but can be powered. The high strength enclosed track design keeps rolling surfaces clean, which contributes to easier crane movement and longer wheel and track life. The tracks' low weight per foot reduces the dead weight, which makes for easier movement, increased worker safety and increased productivity.

Enclosed track workstation bridge cranes push very easily - typically 1 pound of force for 100 pounds of load. This is much easier than an I-beam crane systems that typically takes 3 pounds of force to move every 100 pounds of load. Ergonomically designed, easy to move workstation cranes put less stress on operators. They offer precise load positioning, significant productivity improvements, fewer injuries and less fatigue.Equipment configurations include single or double girder bridge cranes, jib cranes and monorails. Both steel and aluminum cranes are available. Suspension is varied. The options include free standing floor support, ceiling suspended cranes or a combination of the two.

Load suspension trolleys, which ride on wheels inside the enclosed track, have devices that hang below the track opening to support vertical lift devices. These vertical lifting options include hoists, balancers, vacuum lifters and manipulators which contain holding and orienting devices such as hooks, slings, grabs, spreader bars, vacuum devices, custom end effectors and magnets. Enclosed track workstation cranes and monorails can offer ergonomic solutions to a single operation or an entire material handling system.

The technical definition of an Intelligent Assist Device is: A device that employs a hybrid, programmable, computer-human control system to provide human strength and/or speed amplification based on human intent. In layman’s terms, it is a tool that moves seamlessly and precisely with the motion of a person.

Intelligent Assist Devices fill the void between completely manual solutions and completely automated robotic solutions. IAD’s use human Intelligence and adaptability for guidance but the work is done by the device. The fusion of advanced technology and basic human guidance maximizes productivity while minimizing the risk of injury to an operator.

Because IADs use the power of advanced industrial control processors, they can provide many benefits such as:

• Data logging. IADs can log process variables such as the number of cycles, average cycle time, average weight lifted, cumulative weight lifted, and total distance traveled.
• Error-proofing. IADs can be programmed to assist operators by error-proofing tasks. Examples include weighing a case of standard products and indicating if one is not filled, or prohibiting the movement of a part into the storage area designated for another part.
• Preventive and predictive maintenance. IADs have the ability to send messages when routine maintenance is required. Additionally, they can notify personnel in the event of fault conditions.

A well-designed IAD will provide power and logic connections for system integrator use, minimizing the need for additional electronic enclosures. Also, a well-designed IAD can be installed on existing enclosed-track rail systems, thereby allowing easy retrofitting and simple, familiar installation.

Intelligent Assist Devices are a powerful tool for increasing productivity, quality, and safety. By combining the unmatched human ability to coordinate motion and adapt to changing circumstances, with the strength and precision of industrial machinery, IADs will change materials handling.