Ergonomics in Seat Design

Ergonomics is simply the proper design of equipment for worker safety, comfort and productivity. Technology has allowed Sears Manufacturing Company to design and manufacture seats with greatly enhanced ergonomic value and comfort.

Basic requirements for good operator seating include comfort and controlled seated posture. Sears takes care to insure the seating system provides proper support to the hips, ischial area, lower back, shoulders, thighs and arms while still allowing easy operation of all controls or turning in the seat to look rearward.

Seated Posture


Humans vary in size and shape. Sears’ Atlas truck seat product, through extensive anthropometric studies, accommodate that diversity. Sixteen different measurements were taken on nearly 200 truck drivers, both male and female, to build our database. Measurements included:

  • Arm reach
  • Elbow rest height
  • Hip breadth
  • Sitting height
  • Stomach breadth
  • Thigh clearance and weight

Pressure Mapping

Proper support is key to designing a truly comfortable ergonomic seat. Sears Seating utilizes its cushion engineering department to configure contours, foam density (ILD) and testing. Pressure mapping documents pressure inputs and produces a “pressure image” that provides ergonomic information which aids in selecting cushion materials and enhances comfort.Pressure Mapping

Six-axis Ride Simulator

A basic ergonomic seat requirement is to protect the operator from excessive shock and vibration.

In the design of seat suspension system, consideration must be given to vibration characteristics of the machines, including natural frequency of the machine, and input vibration frequency, amplitude and direction that are present on the operator platform. With this information, the seat suspension system can be properly designed to isolate the operator from vibrations.

Portable Data Acquisition Equipment is used to collect “real world” ride data from vehicles in the field. It measures the vibration and accelerations within the operator’s environment, copies, analyzes and stores the data for computer reproduction.

Ride Simulator FullA six-axis computer controlled ride simulator located at Sears Manufacturing Company technical center can recreate in a clinical environment, the ride of a particular machine from the data acquired in the field. It is then used for testing and fine tuning the seat suspension system.

To accommodate the seating requirements of off-road equipment, Sears Seating offers a wide variety of products with an assortment of design attributes to make the equipments operator’s station as safe and comfortable as possible. These seating products are designed to take into account the equipment applications, and the effects the equipment has on the operator. From material handling to farming to heavy construction, there is a Sears seating product specifically designed to meet the needs of the operator.

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