KNIFE WITH THICKNESS GUIDING FOR CUTTING SLICES OF UNIFORM THICKNESS

Abstract: A knife with a thickness gauge for cutting slices of uniform thickness, where a longitudinal guiding blade (2) is fixed at the rear end (X) to a parallel cutting blade (1) in a mutual distance (S). The cutting blade's edge in the steering part (L2) is up towards the centreline of the shaft and where also the cutting blade has a right-angled triangle cross section profile, making the edge seek into the material being cut, but prevented by the guiding blade and consequently working as carpenter's plane iron. The triangular profile gives at the same time enough strength for the cutting blade not to bend lengthways. In the forward part (L1), the cutting blade is thinner and has a downward curved edge which cuts through to the cutting base without the knife's angle against the base need change or is affected. The knife according to the invention may have a fixed slicing thickness, or a mechanism that, by adjustment of the mutual distance between the blade and gauge, makes the slice thickness adjustable.

Description: Knife with thickness guiding for cutting slices of uniform thickness. The invention concerns a knife that combines the thickness gauging qualities of a carpenter's plane iron with the ability of a knife's blade to cut fibre and to cut through e.g. cooked meats, fruit and vegetables into slices of uniform thickness. It is well known that in domestic kitchens and meal-serving establishments cooked meats such as salami preserve their flavour and consistency better whole than ready sliced. It is also much cheaper to buy. However, when an ordinary knife is used, the slices often turn out thick and uneven, making the food uneconomical and less attractive to present. Large kitchens and shops, therefore, use their own, special slicing machines with rotating circular blades and a feeding device that divides the sausage in thin slices. The problem with buying ready-cut meats is that they do not keep long, due to the packaging not being airtight. Smaller machines, similar to those used in large kitchens and shops have been made for domestic use and small kitchen use. These machines are often hand machines. Such machines have not proved all that popular because they are costly, take up bench and cupboard space and usually need to be washed by hand. More often than not, these machines have to be more or less taken apart in order to wash the less accessible parts, otherwise food remains will be left, causing unhygienic conditions. The knife according to the invention aims at cutting the above mentioned foods vertically as simply as the cheese slicer cuts cheese horizontally. Earlier attempts have been made to achieve this by means of an adjustable thickness guiding device (gauge) attached to ordinary blades. These, however, have not proved practicable and have not been manufactured. Ordinary blades were initially used for this invention before the idea was developed further. They proved to be impracticable. German Patent Publication No. 453589 describes a knife with a conventional cutting blade provided with an adjustable thickness guiding device (gauge), which tips up when it comes into contact with the base, so that it cuts through it. The means of attaching the gauge are relatively complicated, involving inter alia two cogwheel linking screws, one of which moves in a radial manner with a very fine margin, in an oblong track in the blade of the knife when the guiding device/gauge tips up. Tests made with the construction have shown that if the gauge overlaps the cutting blade, the slices get stuck between the edge and the guiding device/gauge. After being cut the slice must either have free passage or ample space. The slightest wear in the attachment mechanism will result in a considerable sideways slacking at the front of the guiding device/gauge and the slightest parallel deviation will result in the slices getting stuck behind. The mechanism will also gather small bits and will be difficult to clean. Given the high precision required by the attachment mechanism, screws and cogwheels, the construction will also be very expensive. US patent publication No. 3,091 ,854 deals with a knife with a conventional cutting blade and an adjustable side control. The difference between this mechanism and that described DE patent publication No. 453589 is a slight but noticeable change in the adjusting mechanism and that the guiding/gauge does not tip up when the knife is cutting through to the base. It is presumed that the final cut occurs by tipping the knife itself up to the rear edge so that the foremost part which is free comes down to the base. A similar solution was initially tried during the development of the invention. However, such a solution required a totally unnatural and uncomfortable positioning of the hand where the wrist had to be twisted forward. The same solution with a shaft curved downwards at the rear edge to try and compensate this, proved unsuccessful because the final cut demanded an uncomfortable positioning of the hand. In order for the knife of the invention to work as intended, it is imperative that its design allows it to be held similarly to an ordinary knife. However, the main weaknesses of both the above mentioned publications are connected to the lack of studying or testing of the special demands made to the cutting blade and where usual blade forms as shown simply do not work. This is due to the following: When one tries to cut thin slices with a normal knife, eg. slices of cured meats such as salami, one soon realises that the cutting edge tends to cut 5 shavings. Figure 6 shows the reason for this: the material on the inside is fixed and exerts an outward force (Fi), while the slice on the other side does not exert any pressure on the cutting edge which consequently slips. If the slice becomes thicker, the cutting edge cuts more in accordance with the blade angle. Consequently, the cutting angle (Vk) becomes very unstable and it is more this o phenomenon than the lack of precision of the hand that makes it so difficult to cut very thin slices. This invention seeks to produce a cutting edge for a knife which can cut through a material in the same way as a carpenter's plane, and which is similarly prevented from cutting deeper by the flat plane or guiding mechanism/gauge. s A further problem is that the point or line of force for the cutting edge in an ordinary knife lies considerably lower than that for the hand through the shaft. This too leads to the cutting edge tending to be wobbly. This is shown in Figure 5. For knives intended for ordinary use this is actually an advantage as it makes it easier for the hand to steer the knife, but for a blade for the purpose according o to this invention it has proved to give uneven cuts and a tendency to produce shavings. The cutting edge must therefore be as high or higher that the centre of the shaft. This occurs when the distance (a) between the shaft's centre line (sk) and the cutting edge is zero or negative. Although the mentioned publication does not show a device to this effect, 5 one would probably find that the cutting edge would cut inwards into the material, whereas an ordinary cutting blade as shown would bend away. The force that arises between the gauge and the blade is relatively large and the slightest change in angle results in the slices getting stuck behind the gauge and affecting the bending force even more. If one were to construct an ordinary knife blade 0 with this in mind, the blade would be unreasonably heavy and moreover very costly. This is due to the following relation: The weight at any cross-section is calculated by the width multiplied by the height. The strength against bending increases with the power of 3 of the width, whilst it alters proportionally when the height is changed. For example, halving the height and doubling the width gives the same weight, but the strength against bending sideways increases eightfold. If the width is increased on an ordinary knife blade with a normal cutting edge, the problem of shaving becomes worse as shown in Figure 6, because the force (Fi) becomes greater. It is therefore critical that the cutting edge is high up in the rigid, guiding part, that it steers into the material and that the required rigidity is ensured by a blade that is very wide at the top of the cross-section. The publications referred to do not offer solutions to any of these problems, and judging by the results of the inventor's research (development), the constructions shown in the mentioned publications would hardly work as intended, at least not for slicing cured meats. Examples of embodiments of the knife according to the invention will now be explained making reference to the figures, where: Figure 1 shows a side view of the first design of the knife according to the invention, Figure 1a shows a cross section of the knife through respectively section B-B and A-A according to Figure 1 , Figure 1 b shows a cross section of the knife in section B-B in an angled profile, Figure 1c shows a cross section of the knife through section B-B in a corrugated profile, Figure 2a shows the knife according to Figure 1 at the beginning of an incision, Figure 2b shows the knife at the end of an incision, Figure 3a shows the knife's way of cutting with reference to Figure 2a, Figure 3b shows the knife's way of cutting with regard to Figure 2b, Figure 4 shows the second design of the knife according to the present invention, Figure 4a shows a cross section of the knife through section C-C in Figure 4, Figure 5 shows the third design of the knife according to the present invention, Figure 5b shows a cross section through section C-C of the knife in Figure 5, Figures 6 and 6a show the knife according to the present invention viewed from the side and in cross section respectively, and illustrate the knife's mode of operation, and Figure 7 shows the knife's mode of operation during use. The first embodiment of the knife according to the invention is shown in Figure 1. In the guiding part (L2) it is evident that the cutting edge is placed approximately at the centreline (sk) of the shaft and the thickness guide/gauge (2) fills the place under the cutting edge so that when viewed from the side it resembles an ordinary knife. It is evident from the view B-B in Figure 1a that the cutting edge is shaped almost like a planing tooth so that it will seek to cut into the material while the "triangular" cross-section gives the blade sufficient force against bending sideways. Figure 3a shows how the gauge (2) works against the cutting edge seeking to cut inwards and thus at the reciprocal distance between the blade and the gauge determines the thickness of the slice. Figure 3b shows the final stage of the incision with the downward curved forward part (L1) of the cutting edge. Figure 2a shows how cutting is carried out with a natural handgrip through most of the material. Figure 2b shows the final stage of the incision where the downward curved cutting edge at the forward part of the blade (L1) cuts through the base without the angle in the lengthways axis having to be changed. The combination of the plane formed, high placed cutting edge at the rear and the lower, curved cutting edge at the front causes the knife to pull in towards the cutting surface and does not require a different hand grip than that required by an ordinary knife. It is obvious that the knife can be adapted for left-hand use by reversing the construction. Often the public prefers simple kitchen appliances without moveable parts to complicated mechanisms that tend to break or be inaccurate. The knife according to the invention is therefore initially based on a fixed gauge/guiding blade. The knife can be offered in two or more variants of slice thickness for different uses, which could perhaps be marked in different coloured handles. However, it is also possible to produce knives according to the invention where the slice thickness can be varied. An extremely simple version is shown in Figure 4. Here the guiding blade is fed in as an off-centre bearing axle (4) in the shaft which when turned will vary the distance (S). A locking screw (5) in the shaft will then lock the position. In this manner one avoids edges, gaps and mechanisms in the blade which could collect bits. Another way of adjusting by simply turning a wheel on a screw (6) is shown in Figure 5. Here the guiding blade is attached to the top of the cutting blade in the rear part with a sideways resilient connection where the screw (6) presses the blades apart. A short, rear part of the cutting blade is curved down so that it lies at a level with the base of the guiding blade so that they form a thread for the screw and at the same time prevent the material being cut coming into contact with the screw.

Claims: CLAIMS 1. A knife with thickness guiding for cutting slices of uniform thickness, characterised by a longitudinal guiding blade (2) that is fixed to a parallel cutting blade (1) in the rear (X) at a mutual distance (S), the cutting blade having an edge in the guiding blade's length (L2) nearly up to or over the shaft's (3) centreline (sk), the edge whose cross-section profile has the shape of a right-angled triangle where one side is against the material being cut and the other side is the top constituting the cutting blade's relatively large width for the stiffening of the cutting blade along the length of the guiding blade (L2), but reducing in the cutting blade's free front part (L1), whose ordinary knife shaped cross-section profile has a downwards curved edge to reach the cutting base at the final stage of the incision without the angle of the shaft in relation to the base being affected. 2. A knife according to claim 1 , characterised by a stiffening of the cutting blade (1) in the guiding blade, achieved by the triangular shaped cross-section profile being solid. 3. A knife according to claim 1 , characterised by a stiffening of the cutting blade (1) in the guiding blade, achieved by the shaped cross-section profile being of angled or corrugated material. 4. A knife according to claims 1 to 3, characterised by the cutting blade (1) and the guiding blade (2) instead of being attached are prepared from a single piece of material where the mutual distance (S) is achieved by angling the guiding blade sideways at the rear edge (X). 5. A knife according to claims 1 to 3, characterised by the guiding blade (2) being attached through a longitudinal axle (4) in the shaft (3), and detachable in that the guiding blade can be pulled out. 6. A knife according to claims 1 to 3, characterised by being able to alter the thickness of the slices by adjusting the distance (S) through the moving of the guiding blade (2) sideways at the attachment point (X). 7. A knife according to claim 5, characterised by the longitudinal axle (4) being eccentrically placed in relation to the guiding blade and the distance (S) being adjustable by turning the guiding blade round the axle. 8. A knife according to claim 6, characterised by the guiding blade (2) being attached in a resilient manner to the top of the cutting blade (1) and being sideways adjustable by use of the adjustable screw (6) threaded through the bottom part of the cutting blade at the rear by the shaft.

Inventors: KAROLIUSSEN HILBERG I, KAROLIUSSEN, HILBERG, I.
Applicants: KAROLIUSSEN HILBERG I, KAROLIUSSEN, HILBERG, I.
Application year: 1997
Main classification: B26B3
IPC codes: B26B3