As workplace safety becomes increasingly important, safety knives have crossed over from their origins in shipping and receiving departments to industries such as construction, manufacturing, HVAC installation and plumbing.
The market has in turn evolved to give users plenty of options. So, how do you choose between the options?
Semi-Automatic Safety Knife
The first type of safety knife to enter the market, the semi-automatic safety knife is the granddaddy of them all. This knife is easily adopted in many types of facilities, and the concept behind them is simple: When a user engages the thumb slide and moves the blade across the material being cut, the force of the cut will keep the blade extended so the user can remove their thumb from the slide. Once the blade loses contact with the cutting surface, the blade retracts.
Semi-automatic knives are helpful because safety managers don’t need to remind employees to always close the blade and helps prevent one of the most common accidents: injury due to reaching for a knife and touching an open blade.
Fully Automatic Safety Knife
Every facility has an employee who doesn’t like using a blade that retracts and tapes the blade open to override the safety feature. This is where a fully automatic safety knife comes into play. Once a user starts cutting with this knife, it doesn’t matter whether a thumb is on or off the blade slide; the blade operates independently of the blade lever and will self-retract once the blade loses contact with the cutting surface.
While it may seem like fully automatic makes more sense safety-wise, both of these types of knives are equally safe, and both have their individual uses.
For example, in the shipping and receiving department of an industry like retail clothing, employees are cutting several feet of cardboard sheeting at once. They often need to stop halfway through a cut and reposition their hand because they can’t open larger boxes with just one cut.
A semi-automatic knife’s blade will stay out during the repositioning as long as the user keeps pressure on the thumb slider while an automatic blade will retract when the blade loses contact. The employee will need to extend the blade with her thumb again to begin a new cut. In settings where employees need to make longer or faster cuts, a semi-automatic blade may be better suited to the job as it will require less resetting of the blade when a cut is interrupted.
Concealed Blade Knife
Another type of safety knife is the concealed blade knife, also known as a “zero-liability” knife. In this variety, the blade is always open, but because it’s concealed within a cutting channel, the user is always protected from injury because there is zero exposure to the blade at all times whether cutting or not. This allows for the users to be able to make quick, safe cuts.
This knife style is designed for thinner materials like plastic wrap, plastic strapping, polybag, etc. For semi- and fully automatic knives to function properly, the material must provide some resistance, but materials like shrink wrap are too thin, so a blade can skip and will keep retracting in the middle of cuts. A concealed knife is designed to allow a user to start cutting stretch wrap at the top of a pallet and cut all the way down.
The Rolled Materials Cutter
A spinoff of the concealed blade safety knife is the rolled materials cutter. This type of knife is designed to cut materials that normally come in rolls, like carpet, roofing felt, landscaping mesh, leather and vinyl.
Designed with an enclosed rotary blade, the solid base prevents damage to the surface under the material being cut, and forces the user to cut away from himself. The combination of concealed blade and natural pushing mechanism to aim the cut away provides a user with two types of protection.