Tag: ergonomics

How Force Affects Pushing and Pulling Activities

Pushing and pulling tasks are among the most common industrial activities. Pallets of goods need to be moved from one point to another and equipment needs to be moved to a usage point. Workers at factories, hospitals, distribution centers, grocery stores and many other businesses engage in pushing and pulling activities numerous times a day. The Ergonomics of Manual Material Handling – Pushing and Pulling Tasks provides a useful overview of the costs and consequences of neglecting ergonomics in common industrial tasks that involve pushing and pulling. Click here to read the white paper published by Darcor, an industry leader in the design and manufacture of ergonomic casters and wheels, and Ergoweb, an ergonomic web resource.

While often taken for granted, wheeled carts and equipment are integral to the operation of nearly all manufacturing and distribution facilities as well as many businesses. Musculoskeletal disorders from pushing and pulling injuries cost American businesses billions of dollars each day in medical, insurance, disability and downtime costs. Ergonomically-designed carts, wheels and casters can significantly decrease the incidence of musculoskeletal disorders.

To be effective, ergonomic design for push/pull tasks must consider:

  • Human factors such as height, weight, age, gender, strength, posture and physiological capacity.
  • Task factors including distance moved, forces required to initiate and sustain movement, direction and nature of movement and task duration.
  • Cart/equipment factors such as size, weight, stability, caster/wheel specification and handhold type, height and orientation.
  • Floor/ground factors including surface characteristics, slope and contaminants.

Contrary to popular belief, horizontal push force is more significant than load weight in pushing and pulling tasks. Proper wheel or caster selection and equipment design can enable workers to move thousands of pounds safely and efficiently. Caster/wheel choice alone can reduce push force significantly. Rolling resistance refers to forces that resist movement and defines the amount of force a person must generate and apply to move wheeled equipment.

This force — called the starting or initial force by ergonomists — is always greatest at the start, just before movement begins. Fortunately, starting force must only be exerted briefly. Once acceleration is achieved, less force — called the sustained or rolling force — is required to maintain movement. The final major force that affects cart movement is turning force which can occur while the cart is in motion or during positioning.

Next time: How ergonomics mitigates force.

How Ergonomics Mitigates Force

Horizontal push force is a more significant factor than load weight in pushing and pulling tasks. In moving a wheeled piece of equipment or a load on a wheeled cart, three main forces come into play:

  • Starting or initial force is the effort required to initiate movement. It requires the greatest effort because it must overcome inertia.
  • Sustained or rolling force is the effort required to keep the load in motion and requires significantly less effort if a steady speed is maintained.
  • Turning force is the effort required to turn the load and can be significant as the load is moved into a new direction, often requiring asymmetric body postures and muscle exertion which carry a greater risk of injury.
  • Stopping or positioning force is the effort required to bring the load to a halt or position it in a specific place. Positioning can require significant, multidirectional force, exposing the worker to hazardous postures and muscle exertions.

Ergonomics mitigates these forces through design that seeks to minimize stress on the worker’s body and reduce wasted movement and effort. By reducing unnecessary movements and awkward postures, the force exerted by a worker is more efficiently utilized, thus reducing the amount of force necessary to move a load. This reduces both the time and effort needed to complete a task and the risk of worker injury. To ensure that equipment can be easily used by all members of the workforce, ergonomic design is often adjustable to fit a greater number of workers or is targeted to accommodate the weakest members of the workforce.

Ergonomics works to reduce inertial and dynamic forces, friction and physical interference to decrease the amount of force required to move a load. Considerations in ergonomic design generally include:

  • Floor materials, pitch and slope
  • Load weight, type and quantity per shift
  • Cart or equipment size, weight and design
  • Wheel or caster type, construction, materials, number and placement
  • Handhold type, height, width and placement
  • Control type and placement
  • Route, number of turns, obstacles and amount and type of maneuvering
  • Frequency, duration and repetition of task
  • Body postures required to operate equipment and perform tasks
  • Height, weight, strength and gender of typical worker

Ergonomics Can Significantly Decrease Worker Injuries

Material handlers and laborers suffer more injuries and illnesses than construction workers, truck drivers or, indeed, any other category of workers, according to the U.S. Department of Labor. Material handlers and laborers miss more work days and therefore cost U.S. businesses more money in lost man-hours and higher insurance and healthcare costs than any other worker class.

Numerous studies have proved that ergonomically-designed equipment and systems can significantly decrease worker injury. Many manual tasks necessary during the handling of materials require repetitive motions — pushing, pulling, bending, lifting and carrying — that place undue strain on the human body. These actions can result in sprains, strains, back pain and other musculoskeletal injuries. Back pain is by far the most commonly reported workplace injury in the material handling industry. Treatment is generally lengthy and expensive, gobbling up the lion’s share of healthcare and workers’ compensation costs.

The implementation of an ergonomics program can significantly reduce injuries and their associated costs while improving productivity and worker morale. The Material Handling Industry of America (MHIA) has published a 68-page booklet of tips for improving ergonomics in the material handling industry. Click this link to download MHIA’s free Ergonomic Guidelines for Manual Material Handling. For more information on ergonomically-designed electric and motorized carts, pushers and tuggers, visit the DJ Products website.

Next time we’ll share some of MHIA’s best tips for improving ergonomics in the material handling industry and reducing worker injury and its associated costs.

Proactive Problem Solving Reduces Workplace Injuries

Reducing workplace injuries is every responsible business owner’s goal. Not only do you value your employees’ health and safety, but the cost of ignoring workplace safety — high medical, insurance, workers’ compensation and lost man-hour costs — can be staggering. It pays to be proactive in looking for potential injury-causing problems and coming up with ergonomic solutions that improve the fit between the work and the worker.

Developing a proactive plan to reduce workplace injuries is a four-step process:

  1. Observe and question
  2. Set priorities
  3. Implement improvements
  4. Follow up

1. Observe and question.

Look for clues to possible problem areas in available statistical data. Check injury reports for patterns that indicate higher injury rates for certain tasks or in certain areas. OSHA logs, worker reports and complaints, absence rates, and workers’ compensation reports are good starting points. Ask if your workers’ compensation insurance carrier provides workplace assessment surveys as part of their risk-management services.  

Look at production reports for bottleneck areas. Check quality control reports for poor quality product or service. Problems can indicate areas where workers are having difficulty completing tasks effectively under current conditions. The root cause of such problems is often poorly designed equipment or task procedures.

Spend some time following the entire process of your business from start to finish. Pay particular attention to areas highlighted by the data review. Observe the way workers do their jobs. Watch for risk factors such as awkward postures, repetitive motions, forceful exertions, pressure points or extended periods spent in the same position. Watch for signs of worker discomfort or pain such as self-restricting movements, efforts not to move certain body parts or massaging hands, arms, legs, necks or backs. Pay attention to unnecessary handling and duplication of material or product movement.

Look for ways in which workers have modified standard procedures to make it easier to do their work, including modifications to tools, equipment, workstations or task performance. Talk to managers but also talk to the workers who actually perform the tasks. Ask workers how they would change the work process, operations, tools or equipment to make their jobs less physically demanding and more efficient. You’ll get a clear idea of what isn’t working and may get some excellent suggestions for improvement.

Continued next time

Making the Most of Your Space

A few years back, when business was booming, the answer to the need for increased space because of increased business was simple – upgrade to a larger facility that can handle the increase of inventory.  Now things aren’t quite so simple, increases in margins remain slim and there is constant competition to attract and keep new customers, so many business are leery about taking on greater overheads to try and meet customer demands – instead businesses are being forced to recreate the space that they are in an effort to hold the necessary inventory to satisfy customer demands.

This may mean changing storage racks, warehouse aisles and converting office space in order to make room for additional product storage and this restructuring of space may also mean that the equipment being used may no longer be as effective with the more constrained spaces.  Traditional forklifts can be bulky and may need a good deal of space to  maneuver  around a warehouse  – if you decrease the amount of room for travel there may no longer be enough room for a large forklift to effectively operate.

Though upgrading to smaller, safer and more efficient equipment will bring about an initial investment, unlike assuming a new lease for a larger space, this investment will immediately begin to pay for itself.  The powered carts and lifts from DJ Products allow a single employee to move heavy loads around in the smallest places easily – meaning that your employees won’t struggle at all in the smaller and more cramped spaces and that your business will maintain the same level of productivity despite the fact that your employees have less space to move around in.

Your new equipment will cost less to operate and allow your employees to get the job done quicker, which is exactly the formula you need to attract and keep more customers without having to move into a larger facility.

Electric Tuggers Improve Ergonomics in Material Handling

Improving the ergonomics of material handling decreases worker injuries, improves workplace efficiency and leads to a healthier bottom line. Medical costs, insurance premiums, workers’ compensation payments and lost man-hours soar when ergonomics are ignored. Material handling is one of the most injury-intensive industries, according to the U.S. Department of Labor. Every effort you make to fit the demands of work tasks to the capabilities of your workers (i.e., ergonomics) will decrease costs and ultimately improve profit margins.Material handling requires many actions that can result in serious and expensive musculoskeletal injuries. Repetitive motions, awkward postures and the application of force as workers lift, push, pull, carry and handle materials create daily opportunities for injury. Attention to ergonomics in designing tasks, workspaces and equipment can dramatically decrease the physical demands and injury potential of many material handling activities.Carrying and lifting are the two actions that present the greatest potential for worker injury when handling materials. Today we’ll address tips for ergonomic carrying; on Friday, we’ll share tips for lifting ergonomically.Carrying tasks place stress on the back and shoulders and create contact pressure on the shoulders and hands. When repeatedly strained or overstressed, the effort and force needed to carry materials can cause injury. To decrease injuries caused by carrying, follow these suggestions:

  • Eliminate unnecessary carrying.
  • Minimize the distances materials must be carried and use electric tuggers to carry materials over longer distances.
  • Organize work tasks so that physical demands and work pace increase gradually as muscles warm up.
  • Rotate workers or alternate carrying with non-carrying tasks to prevent overstraining the body and give muscles a chance to rest between efforts.
  • Wear properly fitting gloves to improve grip stability.
  • Reduce load weights and test loads for stability and balance before carrying.
  • Slide, push or roll materials. These actions place less stress on the body than carrying.
  • Use conveyors, slides or chutes to move materials.
  • Use electric tuggers to transport heavy loads.

Pushing vs Pulling Manual Carts

Pushing and pulling are the two most frequent actions workers execute in the course of doing their jobs. So in maneuvering manual carts, which is easier for the worker and creates less risk of injury — pushing or pulling?

Experts say pushing is preferable to pulling for a number of reasons. Research has demonstrated that people are able to exert higher push forces than pull forces. Given that horizontal push force, not the weight of the load or equipment, is the most significant factor in determining the effort required to move a load, that’s a significant consideration in selecting equipment.

Think of what happens to the body when you push something. Your entire body is used to create push force. In pushing an object, your body is more centered which allows you to concentrate force. Limbs are generally held closer to the body, limiting the possibility of extension injuries.

Pulling on the other hand, creates tremendous stress on individual body parts. When you pull an object and you are facing the direction of travel, one arm is stretched behind your body. This places the shoulder and back in awkward postures, increasing the potential for painful injury through overextension or awkward twisting. If you use two hands to pull an object you must have your back to the direction of travel. Walking backwards without a clear view of your path is an invitation to an accident. On an incline momentum can increase unexpectedly and the cart can careen into the worker or “run over” his feet.

There are times when pulling is the only way to maneuver a manual cart into the proper position, but at all other times pulling should be avoided. Pushing is the safer, more ergonomic way to move a manual cart.

Congress Debates Increasing Fines for Worker Injury, Death

Congress is being urged to increase financial penalties for workplace injuries and deaths, according to congressional testimony reported by McClatchy Newspapers. In last week’s hearing before the U.S. House Education and Labor Committee, workers’ advocate groups squared off against industry safety experts to debate increasing penalties when employers don’t protect their workers against hazardous conditions.

Workers’ advocates pressured the federal government to drastically increase fines and implement possible criminal prosecution for senior executives when workers are killed or seriously injured on the job. “The thought process has to be, ‘If I keep doing this, and I keep letting this happen. … I could go to jail,'” David Uhlmann of the University of Michigan School of Law and a former U.S. Department of Justice official, told the House Committee.

Speaking for the opposing view, a workplace safety attorney who helps businesses figure out how to respond appropriately to U.S. labor laws, recommended more clearly defined labor safety laws and more stringent enforcement of existing penalties for employers who exhibit a “callous disregard” for workers’ safety. “There needs to be a balance,” Lawrence Halprin, a lawyer with Keller and Heckman, told the House Committee, noting that confusing labor regulations often contribute to the creation of workplace hazards.

Last week’s hearing was one more volley in the Congressional debate that is accompanying preparation of anticipated legislation to overhaul the 39-year-old Occupational Safety and Health Act (OSHA). With the Obama administration’s apparent blessing, House Democrats are preparing to give OSHA a new and sharper set of teeth. New regulations being considered would dramatically increase employers’ penalties, increase business owners’ accountability and protect workers who speak out about workplace violations. OSHA penalties have not been updated since 1990, and financial penalties were never indexed to inflation. Current penalties for the injury or death of a worker often total just a few thousand dollars.

“Penalties must be meaningful,” said Rep. George Miller, a California Democrat and chairman of the House Education and Labor Committee. “They must function to deter violations. They must get people’s attention.”

However, some committee members are concerned that their Congressional peers may be unduly swayed by the many stories of personal tragedy that have peppered the hearings. Rep. Tom Price, a Georgia Republican, noting that workplace fatalities have declined since 1994, said, “Sometimes Congress gets emotional and draws the wrong conclusions and makes the wrong laws.” Time will tell what happens here, but you might want to weigh in with your Congressman and tell him how you feel.