Factors affecting minimum push and pull forces of manual carts.

Area of Science:

• Biomechanics and Ergonomics
• Materials Science and Engineering
• Physics of Motion

Background:

• Manual material handling with carts is common in various industries.
• Optimizing cart design can reduce physical strain and improve efficiency.
• Understanding factors influencing rolling resistance is crucial for ergonomic design.

Purpose of the Study:

• To quantify the minimum forces required to initiate motion for a 4-wheel cart.
• To investigate the impact of cart weight, wheel dimensions, and wheel orientation on push/pull forces.
• To determine the coefficients of rolling friction across different floor surfaces.

Main Methods:

• Measured minimum push/pull forces for a 4-wheel cart under varying loads (0-181.4 kg).
• Tested four floor materials: smooth concrete, tile, asphalt, and industrial carpet.
• Varied wheel width (25, 38 mm), diameter (51, 102, 153 mm), and orientation (F0R0, F0R90, F90R0, F90R90).

Main Results:

• Minimum push/pull forces increased linearly with cart weight.
• Forces decreased inversely with increasing wheel diameter.
• Wheel width had no significant effect on forces.
• Coefficients of rolling friction varied by floor surface (e.g., 2.2 mm for concrete, 4.5 mm for carpet).
• Forward-aligned wheels (F0R0) generally required the least force.

Conclusions:

• Cart weight and wheel diameter are primary determinants of manual push/pull forces.
• Wheel orientation significantly impacts maneuverability and force requirements, with forward alignment being optimal.
• Floor surface properties substantially influence rolling resistance and required effort.