"Heave-ho" To Heavy Lifting

Material handling safety is a matter of taking calculated manual lifting risks, enlisting the help of an array of safety equipment—or simply losing productivity.

by Susan Friedman

Sure, press downtime is a major thorn in productivity's side, but how far will any print job progress if key workers are absent—home nursing back injuries caused by heavy lifting?

Material handling safety's effect on operation efficiencies and profits could be comparable to the impact of digital prepress or streamlined makeready. A plethora of medical and insurance data shows why.

According to the Ergonomics Assist Systems Equipment (E.A.S.E.) Council of Material Handling Industry, back disorders are most costly in terms of workers' compensation and lost time. The Bureau of Labor Statistics (BLS) estimates manual materials handling injuries represent 35 percent of workers' compensation claims. Medical expenses, lost wages, lower productivity and other expenses from these injuries amount to $116 billion annually.

In 1996, BLS reported more than 490,000 occupational back injuries involving days away from work, with a median of six workdays missed. Printing press operators racked up 1,524 back injuries that caused lost time, while the printing and publishing industry as a whole recorded back injuries requiring time off for 44.6 full-time workers per every 10,000.

A heightened watchdog mentality adds to the immediacy of material handling issues. E.A.S.E. warns that OSHA has recently cited ergonomic violations as "willful," under the Workplace Safety Act.

Employers must be taking these statistics seriously, because according to Barbara Webster, a researcher at Liberty Mutual Research Center for Safety and Health, the frequency of material handling injuries has stabilized in recent years. Several soon-to-be released studies actually show a decline in claims for back injuries, she notes. One contributor to this trend could be Early-Return-to-Work programs, which aim to curtail the average duration of disability.

If a worker decides to, or has no choice but to manually lift a heavy object, Webster offers the following injury-prevention pointers:

•Keep the object close to the body; try to avoid a long reach.

•Avoid bending, twisting or jerking motions when lifting.

•Maintain overall physical fitness to boost resiliency to back injuries.

•Implement packaging that makes the 'to-lift-or-not-to-lift' decision more clear-cut. Packaged items should be light enough for anyone to lift easily, or heavy enough to automatically warrant the use of material handling equipment.

Lightening the load

For printers and converters looking to implement or improve material handling ergonomics, suppliers offer a number of unique means to cushion the stress of lifting or transporting.

E.A.S.E. explains that material handling equipment serves two Ergonomic Motion Classifications. The Equipment to Move Product to Worker classification includes machinery for horizontal/vertical rotation, lifting from above or below, tilting/upending, or transfer supported above or below. The Equipment to Move Worker to Product classification includes machinery that lifts from below or supports transfer from below. Following is a sampling of more recent material handling product introductions

A full line of air lift tables from Advance Lifts includes standard lift tables from 1,000 lbs. to 5,000 lbs. capacity; tilt tables from 1,000 lbs. to 6,000 lbs. capacity; lift and tilt tables from 2,000 lbs. to 4,000 lbs. capacity; and lift and turn tables from 1,000 lbs. to 4,000 lbs. capacity. The tables use a facility's air supply as a power source, and have low maintenance requirements because of simple air spring actuation.

Air Technical Industries' (ATI) detachable drive unit, a self-propelled walk-behind drive, can propel or pull any mobile equipment or cargo with the pull of a pin. The battery-powered detachable drive unit is available as an option for any ATI products, including scissor lift tables and hydraulic floor cranes. Propulsion is electro-mechanically driven and a solid-state speed control permits precise positioning with gradual acceleration and deceleration.

Knorr hydraulic stacklifts, offered by Colter & Peterson, allow materials to be taken off and loaded onto pallets at normal working height. The freestanding, mobile stacklifts can be combined with any paper cutter or production line, and are available with adjustable forks or a platform. A height-adjustable infrared light detects the upper edge of the pile to control automatic lifting and lowering. Models range in size from 19" x 28" to 51" x 68".

A restyled control handle on 6,000 lb. and 8,000 lb. capacity Mitsubishi walkie pallet movers features twist grips in a soft, non-slip, textured sponge surface, angled to match the natural orientation of the operator's hand.The new handle allows the operator to use the twist grips, thumb grips or outboard knobs to control directional movement.

A crane upgrade kit from North American Industries protects crane operation in harsh, caustic or acidic environments. A gasketed, NEMA 4X fiberglass or stainless steel enclosure for electronic controls comes with press latches to confirm a perfect seal. All external wires run through water- and gas-tight press seals. Bearings are sealed, while motor windings are covered with a chemical resistant varnish and include seals at all openings.

The Dandy Lift & Tilt from Southworth Products allows operators to feed and unload parts from tote boxes or containers quickly and easily without lifting, bending, stretching or reaching. Elevated and tilted with a foot-actuated hydraulic cylinder, the unit holds totes or containers at a comfortable working height, and at a 30 degree angle that allows operators to easily reach parts even at the bottom of the container. Capacity is 770 lbs.

Systemation's compact, maneuverable, battery-powered Tilt Truk is designed to replace the manual tilt cart, and make handling of loads up to 800 lbs. safe and easy. The driver rides on-board an elevated platform, increasing visibility to help avoid potential hazards. Tilt Truk features include a horn, backup alarm, key switch, parking brake, battery discharge indicator and adjustable backrest for the driver.

The Tilt Master with automatic brake from T&S Equipment increases productivity while reducing back fatigue and injury. The design, which handles capacities to 4,000 lbs. and tilts 90°, allows the operator to get closer to parts to minimize stretching, while the automatic brake protects the unit from shifting during use. T&S also offers a self-propelled hydraulic scissor cart, with forward and reverse motions and a spring-activated steering column to allow the user to turn sharp corners easily while moving smoothly across a floor on 6à x 1 1Ú4à casters. Platform sizes include 23 1Ú2" W x 35 1Ú2" L and 23 1Ú2" W x 39 1Ú2" L. Capacities are 1,200 lbs. and 1,750 lbs.

Tilt-Lock's Tip-Lift for faster, safer and easier roll handling works from a single chain hoist to lift, transport and turn 50 lb. to 2000 lb. rolls of paper, film and foil. Four gravity activated teeth grip the core firmly, and probes are interchangeable. Vacuum packages are available to prevent telescoping of roll material, and can be used in shaft loading applications. A loadleveler attachment provides horizontal stability in handling long and heavy rolls. A fork truck attachment provides an alternative to an overhead hoist.

The Extra Travel Tri-Post Jib from Vestil Manufacturing can maneuver objects over a work cell or help elevate materials for palletizing, with the capacity to handle 300 lb. to 2,000 lb. loads. The 76à high side posts can straddle a work table and allow materials to be handled over a work area, or the two legs can be mounted in front of a work table and the overhead beam cantilevered over the worktable.

Safety In Numbers

Pencils and calculators can also qualify as ergonomic assists, when used in conjunction with the lifting equation for two-handed, manual lifting tasks developed by the National Institute for Safety and Health (NIOSH).

The equation first calculates recommended weight limit (RWL), or the load weight that nearly all healthy workers could lift over a substantial period of time without an increased risk of developing lower back pain. To arrive at the RWL, load constant is multiplied by reduction coefficients for horizontal hand location, vertical hand location, vertical travel distance, asymmetric angle, frequency, and hand-to-object coupling of the lift. The load weight is then divided by the RWL to calculate the lifting index (LI), or a relative estimate of the level of physical stress associated with a manual lifting task.

NIOSH suggests that recommended weight limit can guide the redesign of existing manual lifting jobs or design of new jobs. The lifting index can serve as a comparison tool for the physical stress of two or more jobs, or to help prioritize ergonomic redesign jobs. NIOSH believes lifting tasks with an index greater than 1.0 pose an increased risk for lifting-related lower back pain.

The following example shows how the equation applies to a package printing operation.

Problem: With both hands directly in front of the body, a worker lifts the core of a 35 lb. paper roll from a cart, and then shifts the roll in the hands and holds it by the sides to position it on a machine. Significant control is required at lift destination.

Task variables

Load constant: 35 lbs.

Vertical location of hands: 27" at origin, 10" at destination

Horizontal location of hands: 15" at origin, 20" at destination

Vertical travel distance: 17"

Asymmetric angle: 0 degrees

Frequency: Four lifts/shift

Hand-to-object coupling: Poor

Using the appropriate coefficients, the equation determines recommended weight limits of 28 lbs. at origin and 18.1 lbs. at destination for the rolls. Lifting indexes figure in at 1.3 at origin and 1.9 at destination—well above the 1.0 injury risk threshold. Several job modifications could improve ergonomics, such as bringing the load closer to the worker; raising the height of the destination; improving hand-to-object coupling; or, eliminating the manual lifting component of the job.

(Note: Coefficient tables are provided in the NIOSH lifting equation applications manual, which can be ordered through 1-800-35-NIOSH, or on the web at www.cdc.gov/niosh/94-110.htm)