A device for manual sharpening of knives

Abstract

This utility model relates to sharpening tools and can be used for both household and professional knife sharpening. A device for manually sharpening a cutting tool comprises a housing, a clamping device, a hinged slider, an abrasive element, and a guide pin. The abrasive element is shaped as a half-cylinder with a half-hole, the diameter of which is 0.2-0.4 mm larger than the diameter of the guide pin. The half-cylinder is wrapped in sandpaper, the edges of which fit into the half-hole. The length of the sandpaper coincides with the length of the half-cylinder. A guide pin is located in the half-hole, which presses and holds the edges of the sandpaper. Holders for the abrasive element, the length of which is selected depending on the stroke length of the guide pin, are located on the pin. Use of this device ensures a concave cutting edge of the cutting tool. 4 fig.

Description

[0001] The utility model relates to the field of sharpening tools and can be used for both household and professional sharpening of knives.

[0002] A device for manually sharpening cutting tools is known, comprising a base, a sharpening stone and a clamping device intended for fastening the blade to be sharpened (Patent P 90370).

[0003] The disadvantages of the known device are the difficulty of sharpening the concave cutting edge and uneven wear of the sharpening stone.

[0004] The closest to the claimed solution is a device for manual sharpening of a cutting tool, containing a housing, a clamping device, a slider with a hinge, a guide pin and an abrasive element in the form of a bar with strips of sandpaper glued to it (Patent P 146503).

[0005] The disadvantage of the known device is the difficulty of sharpening the concave cutting edge and uneven wear of the abrasive element.

[0006] The purpose of the proposed technical solution is to simplify the sharpening of knives with a concave cutting edge.

[0007] The said objective is achieved in that in a device for manual sharpening of knives, comprising a housing, a clamping device, a slider with a hinge, an abrasive element and a guide pin, the abrasive element is made in the form of a half-cylinder with a half-hole, the diameter of the half-hole is larger than the diameter of the guide pin by 0.2-0.4 mm, the half-cylinder is wrapped with sandpaper, the edges of the sandpaper enter the half-hole, the length of the sandpaper coincides with the length of the half-cylinder, a guide pin is located in the half-hole, which presses and holds the edges of the sandpaper, holders of the abrasive element are located on the pin, and the length of the abrasive element is selected based on the stroke length of the guide pin.

[0008] The essence of the proposed technical solution is as follows. In this technical solution, the abrasive touches the cutting edge at a single point, unlike a block-shaped abrasive, resulting in a highly smooth concave cutting edge. Furthermore, the uniform wear of the abrasive element allows for more precise control of the sharpening angle of the cutting edge. The design of the device also allows for quick replacement of sanding paper sheets when they are completely worn out.

[0009] The proposed technical solution is explained by drawings, where Fig. 1 shows a device for manual sharpening of knives, side view, Fig. 2 - an abrasive element, a front sectional view, Fig. 3 - the position of the abrasive element when sharpening the cutting edge near the ricasso line, Fig. 4 - a photo of the assembled device.

[0010] The device for manual sharpening of knives contains: a base 1, a clamping device 2, a knife 3, a guide pin 4, a slider with a hinge 5, an abrasive element 6, including a half-cylinder 7, a half-hole 8, a sheet of sandpaper 9, then holders of an abrasive element 10, a handle 11, a ricasso line 12, a cutting edge 13, faces of a half-cylinder 14.

[0011] The proposed technical solution is implemented as follows. The initial sheets of sandpaper are cut into sheets the same length as the half-cylinder 7 (Fig. 1), the length of which is determined by the overall dimensions of the fixture and specified during its design. The width of each sheet is selected such that its edges extend into the half-hole 8 (Fig. 2) to at least half its depth. For sharpening, a set of sandpaper sheets of varying grit sizes is selected, depending on the hardness of the metal and the thickness of the layer to be removed. Next, the sheet of sandpaper 9, intended for installation in the device, is bent in two places in a direction coinciding with the direction of the axis of the semi-cylinder so that the fold lines coincide with the faces 14 of the semi-cylinder 7. Then, a guide pin 4 is placed in the half-hole 8, which holds the sheet of sandpaper 9 from shifting. The gap is 0.2-0.A 4 mm gap between guide pin 4 and half-hole 8 is required to compensate for the thickness of the sanding paper. The abrasive element prepared in this manner is secured using holder 10 for abrasive element 6. A nut screwed onto the thread located on guide pin 4, for example, can be used as a holder. Next, knife 3 is clamped in clamping device 2 (Fig. 1), guide pin 4 is inserted into the hinge located in slider 5, and the slider is set at a height that ensures the desired sharpening angle. After this, the cutting edge 13 is sharpened (Fig. 3), during which the abrasive element 6 is periodically rotated at an angle of up to 180 degrees, rotating the guide pin 4 around its axis by the handle 11, which ensures uniform wear of the sheet of sandpaper 9. In the drawing, the arrows indicate the direction of movement of the abrasive element.To sharpen the cutting edge near the ricasso line 12, the abrasive element 6 is rotated so that one of its edges can closely approach the ricasso line (Fig. 3). The dotted line in the drawing shows the position of the abrasive element when sharpening the cutting edge near the ricasso line (handle 11 is not shown). The half-cylinder can be made of aluminum, plastic, or wood. Fig. 4 shows a knife sharpening device in which the half-cylinder is made of wood.

[0012] The proposed technical solution produces a smoother, concave cutting edge on knives, offers greater flexibility in selecting sandpaper, and allows for quick replacement of worn abrasive sheets. Experience with this device has shown that when sharpening knife cutting edges, a set of sandpaper sheets with grit ratings of 400, 600, 800, 1500, and 2000 can withstand more than 15 uses. One sheet of sandpaper produces an average of four sheets. This means that one set of sandpaper sheets can be used for approximately 60 uses. When using a block-shaped abrasive, its edges will be smoothed, forming a saddle shape, which distorts the cutting edge and sharpening angle. Comparing the cost of a set of sandpaper sheets with the cost of abrasive stones shows that using sandpaper for sharpening and dressing concave cutting edges is more cost-effective.

Claims

A device for manually sharpening knives, comprising a housing, a clamping device, a slider with a hinge, an abrasive element and a guide pin, characterized in that the abrasive element is made in the form of a half-cylinder with a half-hole, the diameter of the half-hole is greater than the diameter of the guide pin by 0.2-0.4 mm, the half-cylinder is wrapped with sandpaper, the edges of the sandpaper enter the half-hole, the length of the sandpaper coincides with the length of the half-cylinder, a guide pin is located in the half-hole, which presses and holds the edges of the sandpaper, holders of the abrasive element are located on the pin, and the length of the abrasive element is selected based on the length of the stroke of the guide pin.

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