SU517676A1 - Paper shredder - Google Patents

Description

The purpose of the invention is to prevent the knives from clogging when grinding paper.

The goal is achieved by making the working surface of the bump stop in the form of a section of a helix constructed relative to the axis of the circular knife with a constant derivative of a polar radius in the angle. The use of such spirals as the working surface of the bumper causes the torsional force directed along the tangential force, regardless of the angle of rotation of the circular knives, to remain constant all the time or increase, approaching K to the circumferential force, depending on whether the angle of inclination remains polar radius is constant or decreases. In this case, the change in the magnitude of the circumferential force, depending on the change in linear velocity at a different distance from the center of the bed, can be neglected.

FIG. 1 shows the proposed machine, a partial vertical section; in fig. 2 is a schematic of the construction of a spiral and shows the forces acting on a piece of paper depending on its distance from the center of the knives.

On the shaft 1 there are rotating disk knives 2 and Fixed lamellar chippers 3, which are rigidly fixed “a. S x 4.

Plot L of the bump 3 is made in the form of a plot of an Archimedean spiral with a pole in the center of the knife. The polar equation of the Archimedean spiral in general form has the form, where r is the polar radius of the spiral

/ - polar angle / C / - helix constants (parameters).

The derivative of the polar radius with respect to the angle () is a constant value, i.e., it does not depend on the change of the giolar angle and has a constant inclination angle to the polar radius. If we denote the radius of the disk

a knife with the letter R, and the value of the mutual overlapping of the knives along the Intercenter line with the letter C, when choosing the intersection profile of the working surface of the baffle with the outer diameter of the knife of a point lying on the vertical polar radius of the spiral, the polar equation of the Archimedean spiral will take the form

r -L -} - K-5C.

Each piece of paper is subjected to the force F, which, when interacting with the working surface A of the bump stop 3, decomposes to the FO force normal to the surface of the bump stop and the buoyant force in, Directed by the 1PO tangential to the work surface A. When moving a piece of paper along the working surface chipper 3 is its distance from the center of the knife. But, despite this, the angle a between the main force and the tangent at the point of its application remains constant, thanks to the implementation of the profile of the working surface of the striker in the form

Archimedean spiral. To eject even smaller pieces, it is obviously necessary to use a helix bumper working surface profile with a decreasing polar angle derivative, for example, a hyperbolic helix.

Claims (1)

Invention Formula A paper shredding device containing a pair of circular knives and plate chippers mounted coaxially to the knives, is designed so that, in order to prevent the knives from clogging, the working surface of each of the chippers is made in the form of a spiral with a constant radius derivative but the angle built around the axis of the knife. V f-uz.i