FI76722C - FAESTANORDNING FOER EN HUGGMASKINS SKIVFORMIGA KNIV. - Google Patents

Description

1 76722

Chipper blade holder.

Resistance to huggsmaskins skivformiga kniv.

The task of the log chipper is to chop the raw wood coming to the pulp mill into chips about 25 mm long and about 5 mm thick. The actual chipping is performed by chipping blades attached to a rotating solid blade wheel with a length of up to 800 ... 1000 mm, a width of e.g. 200 mm and a thickness of 20 ... 25 mm.

Only approx. 50 mm of the width of the blades can be used for sharpening.

The blades weigh up to about 40 kg and there are 8 ... 12 of them in the chipper. Changing the blades to sharpening is laborious and dangerous due to the weight and sharpness of the blades. In addition, their price represents a large part of the operating costs. The price is increased by the mounting notches that can be machined on each blade and a large unused portion of material.

The aim is to reduce the weight of the interchangeable blades and the proportion of material wasted by placing the blades in cartridges. Such an arrangement in the conventional form is represented by the structure according to Figure 1. The cassette is formed by a body 2 to be fitted to the blade wheel 4 and a flange 3 to be tightened by a screw 5. The blade 1 rests against the body 2 on its lower surface when the flange presses it from the upper surface at the point of contact A. The cutting edge The blade is supported in the plane direction against the frame 2 by adjusting screws 6.

The blade 1 is in an oblique position with respect to the direction of action of the tightening screw 5, so that the flange 3 would tend to slide at point A along the surface of the blade. This is prevented by the point of contact B against the body 2. In order to balance the tightening force of the screw 5 on the flange 3, a contact point C is still required. With sufficient dimensioning, the screw 5 presses the blade through the flange at point A with such force that the blade remains firmly against the body 2 despite the shear forces.

Wood chips fly through the blade wheel through the blade opening 7. In order for the blade opening to be sufficiently wide, the part of the body 2 supporting the lower surface of the blade is necessarily made somewhat flexible. Due to the flexibility, the blade moves tightly despite the tightening with each stroke with respect to the blade wheel 4, substantially perpendicular to its plane. This movement is indicated at point A by the vector vl. The other side of the contact point A, the flange 3, is also forced to move so that the contact with the blade is maintained. When the flange is supported in its plane direction at point B, its movement at point A is parallel to the vector v3, which direction is perpendicular to the segment between points A and B. The difference between the motion vectors of the parties of the contact point A, the blade and the flange, is the vector Δ, which indicates the magnitude of the friction formed at the contact point A.

Abrasion at the contact point A causes wear on the flange 3. Due to the wear, the contact point A moves further away from the cutting edge of the blade, which weakens the attachment of the blade. As a result, the expensive flange 3 has to be repaired frequently and also has to be replaced frequently. Carelessness in this respect has caused dangerous blade detachments while the chipper is running. The blade is easily ejected through the chipper housing and even through the wall of the building.

The present invention reduces wear at the tip of the flange 3 at point A. The solution is shown in Figure 2 and the features of the invention are set out in the appended claims.

In the solution of Figure 2, the movement of the flange 3 at the point of contact A in the direction of the blade surface is prevented by its contact with the body 2 at point B. This point is located between the clamping screw 5 and the blade in the immediate vicinity of the blade base. Now the segment between the support points A and B is almost parallel to the blade surface, so at the point of contact A the motion vectors vl and v3 on both sides are almost parallel and the frictional motion is 76622 ke Δ, which is represented by the vector difference. magnitude.

As the tightening of the tightening flange 3 increases, the flange 3 bends and a slip is formed at point C. The displacement v3 of the clamping edge of the clamping flange 3 caused by the working shocks at point A is still perpendicular to the line B-A and due to the position of point B the displacement v3 coincides very close to the direction of the displacement vl at point A of the blade 1. Thus, the slip Δ remains much smaller than in the structure of Figure 1. Instead, in the structure of Figure 2, slippage also occurs at point C due to work shocks.

Claims (2)

4,76722 A fastening device for a disc-shaped blade of a chipper or other similar cutting machine, comprising a clamping flange (3) for pressing the blade (1) and clamping screws (5), the clamping forces of which are absorbed by the support surfaces (A and C) of the clamping flange (3). ) on opposite sides so that the second support surface (A) is between the clamping flange (3) and the blade (1) for pressing the blade against the body (2) by applying a bending stress to the clamping flange (3) of the clamping screws (5) between said support surfaces (A and C) , characterized in that the sliding flange (Δ) of the clamping flange (3) due to the clamping force of the clamping screws (5) is prevented by placing the clamping flange (3) against the blade-supporting frame (2) on the surface (B) between the clamping screws (5) and the blade (1). Fastening device according to Claim 1, characterized in that the non-slip contact surface (B) of the clamping flange (3) is non-uniform in the longitudinal direction of the blade so as to interrupt the reinforcements formed on the clamping flange (3) at the clamping screws (5).