The ubiquitous wheelbarrow essentially consists of three components using commonly available materials of steel or hardwood. These components are characterized by,
• The frame (with handles)
• The transport receptacle
• The wheels)
Each of these parts plays its own essential role in the effectiveness or fitness for purpose, ease of operation, and durability of the tool.
The structure
The frame
The materials used for the frame consist of two main materials, one is a hardwood and steel flat bar (bolted together) or secondly combinations of steel tubing and steel flat bar (bolted or welded together) the The use of each of the two main materials depend on the availability and ease of processing in the region of manufacture.
The transport receptacle
The shipping receptacle will be of a metallic or polymeric (plastic) material (rigid or flexible) generally depending on the use and manufacturing technique. Metal receptacles may be galvanized, powder coated, or painted. An open box shape (with or without sloped sides) will almost always be used to facilitate transport of particulate materials; however, a flatbed can also be used for transporting self-supporting stackable materials, eg fired bricks.
The wheels)
The wheel(s), single or double, will consist of a variety of fabricated configurations, these could be, various diameters of a round section, solid, molded polymeric material, permanently affixed to (usually) suitably pressed steel rims with an axle system, or pneumatic tires contained in the classic configuration that would allow the removal of the tire, for its repair, in the event of a puncture.
The design and engineering of each of the above components contributes, as indicated above, substantially to the efficiency, effectiveness and durability of the truck.
The materials
The frame
The two different construction materials of hardwood and steel and their individual assembly each contribute uniquely to the effectiveness and durability of the tool.
Traditional wood construction consisting of a strong, straight load-bearing beam allows for higher loads and greater leverage with comparatively less mass than an equivalent steel counterpart, but requires a greater number of constituent parts than a steel tube construction. steel. While the use of tubular steel, which can be punched in a single operation, allows for the lower cost fabrication of a one-piece construction wheelbarrow frame, albeit with less load capacity due to the restriction in tube length one piece.
The die-pressed tubular steel frame has itself induced an inherent weakness in that due to the die and press structure, the resulting shape of the frame can result in excessive stress in the resulting curves, thus the wall of the outer circumference is unacceptably thinned and the inner part of the circumference is compressed resulting in wavy skin. This results in poor flexural strength and is often the cause of frame failure during heavy use, particularly when using thin-walled tubes. Internal rust also attacks these stressed areas, contributing to premature failure. The size of the pressed steel frame itself restricts the size of the shipping container to a 65 l (3.2 cu ft) container, while the wooden section allows for options up to 300 l (11 cu ft).
The transport receptacle
The shipping container material of construction (commercially) consists of pressed steel or a molded ribbed polymer or a flexible tear resistant woven fabric. (The latter is an aberration used for wheelbarrows whose frame can be folded up for convenient storage)
Pressed steel has been the traditional norm, but commercial cost pressures have resulted in ever thinner gauges of metal and therefore less wear resistance. The advent of polymeric substitutes for steel has resulted in cost competitive alternatives. An added benefit has been a product that resists environmental attack such as rust and acids/alkalis. With a considerably lower density than steel, a lighter tray is obtained.
The wheels)
A significant contributor to the effectiveness of a wheelbarrow is the type of wheel structure and the materials used.
If the tire width is too narrow, any journey on sandy ground will be extremely difficult because the wheel will sink into the sand and make maneuvering equally difficult. The outside diameter of the wheel will also prove problematic. Too small and rolling resistance will increase by orders of magnitude.
The wheel bearings used will determine the life of the wheel.
Synthetic bushings that are kept clean and ungreased will generally outlast the wheelbarrow and provide excellent service.