Belt sharpener

A belt sharpener comprises a drive pulley, a belt tensioner, a contact roller, an idler pulley and an endless abrasive belt mounted for rotation between them. The belt sharpener also includes a primary and a secondary guides adapted to hold a blade at a desired angle with respect to the abrasive belt.

BACKGROUND OF THE INVENTION

Technical Field

The present invention relates to the field of knife sharpeners. More specifically, the invention relates to belt sharpeners.

Description of the Related Art

Cutting tools are used in a variety of applications to cut or otherwise remove material from a workpiece. A variety of cutting tools are well known in the art, including but not limited to knives, scissors, shears, blades, chisels, etc.

A cutting tool often has one or more laterally extending, straight or curvilinear cutting edges along which pressure is applied to make a cut. The cutting edge is often defined along the intersection of opposing surfaces (bevels) that intersect along a line that lies along the cutting edge.

In some cutting tools, such as conventional kitchen knives, the opposing surfaces are generally symmetric; other cutting tools, such as scissors, have a first opposing surface that extends in a substantially normal direction, and a second opposing surface that is skewed with respect to the first surface. More complex geometries can also be used, such as multiple sets of bevels at different respective angles that taper to the cutting edge.

Cutting tools can become dull over time after extended use, and thus it can be desirable to subject a dulled cutting tool to a sharpening operation to restore the cutting edge to a greater level of sharpness.

In the following detailed description of the invention, numerous specific details are set forth in order to provide a thorough understanding of the invention. However, it will be obvious to one skilled in the art that the invention may be used without these specific details. In other instances well-known procedures, components, and elements are not described here in detail so as not to unnecessarily obscure aspects of the invention. It will be readily understood that the components of the present invention, as generally described and illustrated in the figures, may be arranged and designed in a wide variety of different configurations. Thus, the following more detailed description of the embodiments of the devices and methods of the present invention, as represented in the figures, is not intended to limit the scope of the invention, but is merely representative of selected embodiments of the invention.

SUMMARY OF THE INVENTION

A belt sharpener of the present invention includes a drive pulley, a belt tensioner, a contact roller with an outer layer made of elastically deformable material and an idler pulley attached to a frame. The belt sharpener also includes an endless abrasive belt mounted for rotation between the drive pulley, belt tensioner, contact roller and the idler pulley. The belt sharpener further comprises a primary and secondary guide adapted to hold a blade at a desired angle towards the abrasive belt. The angle of the primary and secondary guide is set independently by using two different angle selectors. In case of mechanically connected primary and secondary guide, the angle for both of them is set by a single angle selector.

DETAILED DESCRIPTION OF THE INVENTION

FIG. 1,FIG. 3, andFIG. 4show a belt sharpener100constructed in accordance with an embodiment of the present invention. The belt sharpener100includes a base114and a vertical frame115attached to the base114. The belt sharpener100further comprises a drive pulley102, a belt tensioner103, a contact roller104, an idler pulley105and an endless abrasive belt101mounted for rotation between them. The drive pulley102, belt tensioner103, contact roller104and idler pulley105are attached to the frame115.

The drive pulley102is connected to an electric motor113and is responsible for the continuous movement of the abrasive belt101. The contact roller104includes an outer layer106that coats the contact roller104. The layer106is made of a suitable natural or synthetic material that can be elastically deformed when pressed by an external force (for example spongy or rubbery material).

The belt sharpener100also includes a primary blade guide107with a primary blade stop108and a secondary blade guide109with a secondary blade stop110.

The primary guide107are comprised of a left primary guide107alocated to the left of the abrasive belt101and the contact roller104, and a right primary guide107blocated to the right of the abrasive belt101and the contact roller104. The primary blade guide107are adapted to move around a primary axis116which is parallel to and located below the surface of the abrasive belt101, and perpendicular to the direction of the motion of the abrasive belt101.

The primary blade stop108is comprised of a left primary post108aattached to the left primary guide107a, near the primary axis116, and a right primary post108battached to the right primary guide107b, near the primary axis116.

The secondary guide109are comprised of a left secondary guide109alocated to the left of the abrasive belt101, and a right secondary guide109blocated to the right of the abrasive belt101. The secondary blade guide109are adapted to move around a secondary axis117which is parallel to and located below the surface of the abrasive belt101, and perpendicular to the direction of the motion of the abrasive belt101.

The secondary blade stop110is comprised of a left secondary post110aattached to the left secondary guide109a, near the secondary axis117, and a right secondary post110battached to the right secondary guide109b, near the secondary axis117.

The guide107,109are adapted to ensure the desired presentation angle of the blade200to the abrasive belt101. The desired presentation angle of the blade200to the abrasive belt101may be adjusted by an angle selector112, connected to the primary blade guide107, and through a mechanical connector111to the secondary blade guide109. This connection guarantees that the sharpening angle (set by the angle selector112) remains the same for the primary107and for the secondary109blade guide.

Another embodiment of the present invention is depicted inFIG. 5. In this embodiment, the angles of the primary107and the secondary109guide are adjusted separately, by a primary angle selector112aand a secondary angle selector112brespectively.

During the first phase of the sharpening process, the blade200is placed on the primary guide107(with the cutting edge203superimposed on the primary axis116), the primary bevel202of the blade200is pressed against the abrasive belt101and the contact roller104. This pressure creates a local depression in the layer106, located beneath the belt101, thus causing the abrasive belt101to sharpen the primary bevel202to a concave shape.

During the second phase of the sharpening process, the blade200is placed on the secondary guide109(with the cutting edge203superimposed on the secondary axis117), and the secondary bevel201of the blade200is pressed against the abrasive belt101and sharpened to a convex shape.

The sharpening of the primary bevel202provides a leaner form to the blade200, thus aiding in (by reducing the amount of removed blade material) sharpening of the secondary bevel201to a convex shape.

During the sharpening process, the abrasive belt101can be changed to different abrasive grits and materials by pressing the belt tensioner103.