Final answer:
The two most common types of utility knives are the retractable or sliding blade utility knife and the fixed blade utility knife. While a three-blade design is acknowledged for efficiency and safety, standard utility knives typically have a single blade. These tools have a long history of evolution, with ancient examples made with materials like iron and bronze.
Step-by-step explanation:
The two most common types of utility knives are retractable or sliding blade utility knives and fixed blade utility knives. A retractable or sliding blade knife typically features a mechanism that allows the blade to slide in and out of the handle, ensuring safety when the knife is not in use and allowing for variable blade length during cutting. The fixed blade utility knife, on the other hand, has a non-retractable blade that is permanently exposed. This design is meant for heavy-duty tasks where maximum blade stability is crucial.
According to Figure 13, the three-blade design is often deemed the most efficient for cutting, due to its balance of safety and performance, as it has a lower tip speed which makes it less dangerous than 2 or 1-blade designs. However, most common utility knives feature either a single retractable blade or a single fixed blade, not multiple blades.
Utility knives have evolved significantly over time, with ancient examples such as the knife with an iron blade and hollow bronze handle from the 1st millennium BC, as displayed in Figure 3.1.