Work Tasks

Employees unpack boxes loaded with empty bottles. Empty bottles are loaded into machinery that fills them with product. Empty boxes are placed on a conveyor for repacking at the end of the line after the bottles have been filled with liquid. The empty bottles are filled by machinery and are then presented to employees for re-packing into shipping boxes. They are brought to the employees by conveyors and are manually lifted into boxes. The boxes sit on a conveyor that runs between the bottle conveyor and the employees. Each employee places some of the bottles into the box, passes it to the next employee who places more bottles inside until the box is filled. The conveyor, which holds the box during loading, then takes the filled box to an automatic box-sealing machine. After boxes are sealed, they are manually loaded onto pallets seven tiers high for shipment. Employees stand for the duration of the task.

Exposures

• Wrist in a deviated posture, to move bottles from the supply conveyor to the packing box
• Repeated deep torso flexions to place boxes on pallets that rest at floor height
• Reaching to distant or elevated positions
• Repeatedly flexing the torso especially with significant loads in the hand
• Extended periods of standing
• Repeated forceful motions
• Elongated pinch grips
• Extended reaches
• Lifting

Controls

• An automatic box filler that loads bottles from the conveyor belt into boxes should be developed or purchased.
• Redesign such that bottles are loaded into boxes without physically lifting them from the conveyor or by moving them with a cradling action using both hands. One system that could accomplish this would utilize a peninsula-type loading area that diverges from the main conveyor. Placing a side opening box at the end of the peninsula would permit sliding bottles diverted from the main line into the box without lifting each one prior to insertion. After the box is filled, a stop could be released that would allow the box to slide down a ramp to a conveyor, which would take it to the loading area.
• Placing the box supply conveyor behind the product conveyor and tilting it towards the loading employee about 60 to 70 degrees with the bottom side of the box at about the product conveyor height should permit loading using a cradling and sliding motion rather than repeated lifting.
• Rotatable palletizers or other height adjustable devices should be provided for all pallet stacking tasks. Palletizers enable employees to perform most lifts at the ergonomically desirable level of about waist height and reduces the amount of deep torso flexion required during the task. The rotating feature permits employees to easily reorient the pallet for better access to loading areas, thus keeping the load in close to the torso, which reduces the stress on the lower back.
• The height at which pallets are loaded should be limited to no higher than can be accomplished while keeping the elbows in close to the torso.
• Administratively limit the height a pallet can be stacked or, if pallets must be stacked higher, develop a multi-level loading area where the pallet height can be lowered below floor level during the lifting process. This will allow for loading of the highest tier while maintaining ergonomically neutral postures.
• Jobs should be classified as to the nature and extent of exertion and a rotation schedule should be created that allows for as much variation as possible in the distribution and frequency of musculoskeletal activity. Ideally, employees who perform repeated finger intensive motions should be rotated to tasks that do not require these actions, such as the dumper position, the stocket position, or the packer position, which places cardboard inserts into the packing box.
• Work-rest schedules should be developed and enforced. Generally, a minimum of a 15 minute rest break at least every two hours is required.
• Repetitions of motions in excess of 1500 to 2000 repetitions per hour, have been shown to cause tendon and sheath swelling. Generally, repetitions should be kept below 1500 per hour especially for employees who show symptoms of repetitive motion injuries. Employees who show symptoms may have to slow down or be rotated on a more frequent basis to tasks that do not require repeated reaching and finger actions.
• Reduce the distance employees must reach to perform tasks. Generally, reaches should be limited to no more than 14 to 16 inches horizontally and no higher than shoulder height vertically. Torso flexions should be limited to no more than 6 to 10 degrees from vertical. All tasks should be positioned such that they can be performed with the elbows close to the torso.
• Where employees are required to stand for long periods of time, provide anti-fatigue mats and/or shoes with well-cushioned insteps and insoles.
• Provide sit/stand stools to employees so they can adjust the positions at which they work to minimize the amount of loading on any one muscle group.
• Provide foot rests 4 to 6 inches above the floor, allowing employees to rest one leg while standing. Foot rests are believed to alleviate back stress as well as minimize foot fatigue.