Your Problem is Force, not Weight: Why you shouldn’t use more people to solve your pushing and pulling issues

posted on: Wednesday July 6, 2016

Xpress SingledrevaMusculoskeletal injuries from pushing and pulling tasks cost American businesses billions every year. Acute injuries aren’t the most commonly-sustained, either. Rather, chronic injuries that occur over time cost millions of people jobs, medical expenses, insurance hikes, disability, and lost labor or work. Materials handling relies heavily on the pushing and pulling of carts. It’s tempting to think that the cart weight is the issue and that recruiting more people to move a heavy cart is the solution. Both assumptions are wrong, and they can result in devastating costs to the employee and employer.

Whether a person can safely and easily push or pull a cart has to do with far more than how much weight the load bears. The issue is actually horizontal push force, of which there are four kinds to consider:

  1. Starting/initial force. This force requires the greatest effort, as the employee must overcome inertia to get a stationary object moving. This is also considered “Draw-bar Pull,” and is always considered when designing an ergonomic solution.
  2. Sustained/rolling force. Once the load is moving, this is the force required to keep it going. This requires much less force.
  3. Turning force. Turning a load requires different forces, and varies depending on the turn. If the load has to change directions, there are numerous changes to body posture and distribution of energy.
  4. Stopping/positioning force. Halting or positioning a load at its stopping point can require multidirectional forces from the employee, which requires a great deal of energy, too.

The significance of these forces depend not on the weight of the load, but on overcoming several factors:

  • Human – strength, posture, height, gender, age, and weight all affect a person’s physical ability to exert force onto a load.
  • Task – the distance a load must move, how many times it’s moved, the direction of movement, and the nature of movement all influence the load.
  • Equipment and carts – caster and wheels play a significant role in force, as do the stability, size, weight, height, and orientation of the cart and/or equipment.
  • Floor/ground – characteristics of the floor that affect required force include obstacles, surface condition (slippery, sticky, etc.), and slope.

When it comes to force, human limitations are one of the factors to overcome, and should not be considered as part of the solution. Ergonomic equipment is designed specifically with all of the forces and limiting factors in mind. Rather than subject more employees to dangerous physical labor (taking away from productivity), using the right ergonomic equipment will give one person a task that requires limited:

  • Unnecessary movements
  • Awkward postures
  • Force
  • Stress and/or strain
  • Time needed to accomplish the task
  • Time needed to recover from the task

For pushing and pulling, the most widely-used solution is an electric tug or cart-pusher. This equipment is ergonomically designed for one operator of any size to effortlessly overcome the “Draw-bar Pull” and maneuver a load freely. These units vary in capability depending on wheel/roll resistance of your carts and the initial force required for the load. Load Mover Inc. will help you determine your “Draw-bar Pull” and other factors to identify the kind of equipment that will best serve you and your employees. Call or email us today to improve your operations immediately: 952-767-1720;