Food slicers of a type known as mandoline slicers are well known. Slicers of this type have a knife or blade having a blade body and a leading edge on the blade body for cutting food. The slicer is operated by directing a quantity of food in a direction toward the knife edge to be cut. Under ideal circumstances, the planar blade body would be arranged generally parallel with the direction in which the food is moved.
A bulk quantity of food is typically placed on a support surface, often referred to as a runway, and then slid across the runway toward the blade edge. The blade is offset from the runway, and the offset distance provides a thickness or depth of the cut made in the food as it is pushed into the blade. After the food passes by the blade, the uncut portion passes above the blade and onto a landing, and the sliced portion passes below the blade and separates from the rest of the food bulk.
The blade edge, despite cutting through the food, provides a resistance force. For example, a straight blade edge that is perpendicular or transverse to the direction of cutting may require a relatively high force applied to the food. The straight blade makes a line contact across a square face of the food bulk, and the entire blade edge enters the food bulk at generally the same time. To ease the entrance of the blade into the food, it is known to set the blade edge at an angle from the direction of cutting. This allows a first portion of the blade to enter the food at the oblique angle, and the rest of the blade edge trails and enters subsequent to the first portion, thus requiring a lower initial force to begin a cut of the bulk food. However, the resistance between the blade and the food results in a force that tends to direct or push the food to one side of the slicer.
This issue may be remedied by providing a pair of blade edges, the blade edges set oblique to the direction of cutting but opposite to each other. For instance, the blade often is arranged with a pair of blade edges that form a V-shape, and food is directed toward the center of the intersection of the blade edges in the center of the blade. The lateral forces on the food as a result of the resistance from the blade passing through the food are balanced between the blade edges, each edge tending to force the food towards the other blade edge, directing the food inwardly towards the center of the blade.
In order to select a slice thickness, some mandoline slicers are adjustable. That is, the slicer is adjustable so that the offset between the blade and the runway may be selected. However, this adjustment presents a number of issues.
First, the plane of the blade may not remain parallel to the runway, instead tilting somewhat. This results in an increase in resistance, requiring the user to have to exert a greater force to overcome the resistance. In detail, if the blade edge is angled or tilted upward relative to the landing, the blade tends to pull the food downward. This downward pull causes greater friction or resistance between the food and the runway, and may compress the food as it passes towards the blade. This results in a slice in which the trailing portion gradually increases so that the cross-section of the slide is not even or constant. Conversely, a blade angled upward will cause the food to lift upward resulting in a slice where the trailing portion gradually decreases, and the slice again has an uneven cross-section.
Additional issues arise when the adjustable slicer includes a V-shaped blade. In order to match the V-shape of the blade, the runway has a V-shaped end. If the runway is simply tilted downward to increase the thickness of the cut portion, for instance, the offset between the blade edge and the runway varies from a maximum at the apex of the V-shapes to a minimum at the forward-most portion of the V-shapes.
Various attempts have been made to address these problems by adjusting the runway relative to a co-planar blade and landing so as to maintain the runway in a plane generally parallel to the blade. One example of such a slicer is shown in U.S. Pat. No. 6,732,622, to Vincent. The '622 patent shows a ramp, or runway, that is raised or lowered so that it generally remains parallel to a landing. The ramp is shifted by a pair of locking screws on the sides of a frame. The screws must be properly adjusted, relative to each other, or the ramp will end up tilted to one side. The slicer also requires a number of steps, as the screws must be loosened, the ramp shifted by eye to a desired position for a slice thickness, and then each screw must be tightened. This makes fine tuning of the slice thickness difficult. Furthermore, the ramp is secured via laterally extending pegs received in oblique holes so that the ramp actually moves horizontally relative to the blade edge, thus resulting in less precision with cutting.
Another design is shown in U.S. Pat. No. 5,765,572, to Kim. This system has a single adjusting nut, so it is easier to operate than the slicer of the '622 patent. However, the ramp or sizing plate shifts horizontally relative to the blade in the same manner as the '622 patent.
Accordingly, there has been a need for an improved mandoline-type food slicer.