SU927199A1 - Spiral knife - Google Patents

Description

(5) SPIRAL KNIFE

one

The invention relates to tools for cutting logs, tree felling and can be used in the forest industry.

Known HOW chipless cutting, comprising a housing with a cutting edge adjacent to the outer spiral D.

Also known is a spiral knife, comprising a body with a cutting edge and side surfaces inclined to the cutting plane 2}

A disadvantage of the known knife designs is the high friction resistance along the side surfaces of the knife body.

The purpose of the invention is to reduce the resistance to friction on the side surfaces of the knife.

The goal is achieved by the fact that the inclination of the side surfaces of the knife body is made in concentric circles at an angle to the cutting plane equal to 0.5 ° -13 °, and the central angle

, enclosed between the initial and final radii of its vectors is 30 ° -120 °.

FIG. 1 image en knife, general view; in fig. 2 is a section A-A in FIG. one.

Spiral comprises a housing 1, a cutting edge 2 adjacent to the helix 3, and an axis of rotation. The side surfaces 5 of the knife body are in concentric circles 6, the centers of which coincide with the axis of rotation of the knife in the direction opposite to the opposite; Cutting direction (the direction of the working rotation of the knife or the cutting direction is indicated by the arrow w, inclined to the cutting plane 7 at an angle d of 0.5-13 and form a tapering part 8 of the knife body 1.

The central angle of the knife L (or the sector of the knife), enclosed between its initial 9 and final 10 radius vectors, with the top at the center of rotation 4, is 30-120.

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Such a central angle, A, provides the possibility of making the knife body tapering in the directions of concentric circles. The set of features: the size of the sector of the knife body A 30-120 ° and the angles of inclination of its side surfaces 5 about 0.5 13 ° -; leads to a sickle-shaped knife, the cutting edge of which is located on the outer helix 3 (for a sickle-shaped knife, helix 3 is external to the inner helix 11).

Re) the edge 2 is formed by a wedge 12 and can be made in a continuous spiral 3. or the tooth 13 can be inscribed in the spiral 3 (figure 2). The wedge 12 part of the knife passes into the area C with edges 15i parallel to the cutting plane 7. This area is introduced taking into account the wear of the knife during its sharpening. The length of the section 14 in the direction of cutting along concentric circles is small, since the bladeless cutting knife is rarely sharpened.

The spiral knife is mounted on the flywheel 1b, which has a counterweight 17 for balancing the centrifugal forces.

Spiral knife works as follows.

When the knife is rotated in the direction of the arrow W, the continuous cutting edge 2 or the cutting edges of the teeth 13 are successively cut into the wood. In this case, the wedge 12, crushing the wood of the whip 18, pushes it to the side. See that wood, as a result of its elastic recovery, acts on the edges 15 by pressure q (H / MM), and the strength of friction on these edges is equal to PTP 2qFt

where P is the contact area of one face 15 (parallel to the cutting plane) with wood and / x. - coefficient of friction slip.

If there is a narrowing part 8 of the knife body with an inclination along the concentric circumferences of the side over the top of the knife 5 at an angle with t, an elastic recovery of this wood does not have time to affect the narrowing part 8 of the knife, thereby reducing the resistance of friction forces on the side surfaces of the body knife and it is possible to use the proposed spiral knife for cutting the whips 18 with a diameter of 40-60 cm or more.

Claims (2)

1. USSR author's certificate No. 4107 + 1, .kl. A 01 C 23/08, 19/1. 2. USSR Author's Certificate No. it76856, Clo A 01 G 23/08, 1973 (prototype). f W f2  A 5 Rig.g.