Solid material comminution or disintegration – Apparatus – Comminuting surface provided with openings to permit...
Reexamination Certificate
1999-10-06
2001-07-24
Rosenbaum, Mark (Department: 3725)
Solid material comminution or disintegration
Apparatus
Comminuting surface provided with openings to permit...
C241S294000, C241S300000
Reexamination Certificate
active
06264124
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to a wearing element for a comminuting machine whose rotating knife head includes a support disc, a support ring arranged coaxially to the support disc and knife carriers which are distributed uniformly over the circumference and are arranged axially between the support disc and the support ring. The wearing element is composed of a plate having a certain thickness and the shape of a ring sector. The plate covers the inner periphery of the outer side of the support ring and has in the area of the gap between two knife carriers an inclined surface extending over the thickness of the wearing element toward the support ring. The wearing element is an element which is subject to wear during normal use.
2. Description of the Related Art
Comminuting machines of the above-described type, as they are known, for example, from DE 35 05 077 C2, are suitable, among other purposes, for comminuting long timber. The long timber to be cut is cyclically moved in the axial direction up to a stop plate in the interior of the cutting space of a comminuting machine. While the portion of the long timber extending out of the cutting space is secured, a rotating knife head moves during each work cycle transversely of the axial direction of the timber and shortens the timber over a length which corresponds to the depth of the cutting space. Subsequently, the knife head is returned into the initial position, the pieces of timber are once again moved up to the stop in the cutting space and a new work cycle begins.
In machines of this type, the knife head which defines the cutting space is composed of a support disc, a support ring arranged coaxially to the support disc and knife carriers arranged between the support disc and the support ring. The knife carriers are uniformly distributed over the circumference of the knife head, wherein an axial gap is defined as a result of a predetermined distance between the individual knife carriers. The chips are moved from the cutting space and the area of the knife head through this gap.
In order to be capable of comminuting also the portion of the timber extending into the cutting space, it is necessary that the knives held in the knife carriers extend at least up to the outer side of the carrier ring. If this were not the case, the support ring would contact the timber with its inner surface and would prevent a transverse movement of the knife head. A problem in this connection is the removal of the chips produced in the area of the support ring. In order to ensure that the chips are conducted into the interior of the comminuting machine, the inner surface of the support ring is provided in the gap area between two knife carriers over the entire width thereof with an inclined surface portion extending toward the interior of the comminuting machine. This inclined surface portion forms a duct through which the chips are conducted toward the gap between two knife carriers.
When such comminuting machines are operated, significant wear phenomena can be observed in the area of the duct which makes it necessary to prematurely exchange the support ring. This wear is due to impurities in the material to be comminuted in the form of water, sand and dirt which over time lead to crack-like erosions and impair the strength of the support ring as a result.
In order to prevent these problems, plate-shaped wearing elements have been arranged at the inner circumference of the outer side of the support ring, wherein these plate-shaped wearing elements have at the location of the duct an inclined surface portion and which over the thickness thereof protect a portion of the inner surface of the support ring. This measure has turned out not to be sufficient because wear phenomena still occur at the non-protected portion of the inner surface of the support ring and at the inner side thereof.
SUMMARY OF THE INVENTION
Therefore, it is the primary object of the present invention to provide a wearing element which essentially prevents wear of the support ring.
In accordance with the present invention, a wearing lip for protecting the support ring is arranged so as to extend or elongate the inclined surface portion.
The configuration according to the present invention provides the advantage that the wearing element covers the support ring over the entire length of the chip removing duct. The present invention intentionally disregards the possible argument that a wearing lip cannot withstand the high loads occurring during the hard operation of a comminuting machine of this type. However, as a result of the invention, the support ring is no longer subjected to a direct wear load, so that the intervals for exchanging the support ring are increased. The wearing elements, on the other hand, which are of a sufficiently wear-resistant material, can be easily exchanged because of their size and easy accessibility. Consequently, the invention reduces the costs for material as well as for personnel.
Another advantage of the invention is the special configuration of the wearing element which makes it possible to use it as a replacement part for wear plates already in use. Consequently, in existing comminuting machines, it is not necessary to exchange the entire support ring but only the wear plates.
In accordance with a special embodiment of the present invention, the wearing element is positioned on the support ring in such a way that it covers with its middle portion approximately the gap between two knife carriers. As a result, the wearing lip can be fastened at the wearing element in a statically favorable position. Sufficient space for a problem-free chip removal is provided by a recess at the edge of the wearing element, so that the wearing lip and, thus, the chip removing duct are located in a relatively low position at the wearing element.
In accordance with an advantageous feature, the cross-section of the wearing lip is trapezoidally shaped. This protects the bottom of the chip removing duct which is subjected to high loads. When wear phenomena occur at the side surfaces of the chip removing duct, it is advantageous to equip the wearing lip with a U-shaped cross-section, so that the entire chip removing duct is protected.
The various features of novelty which characterize the invention are pointed out with particularity in the claims annexed to and forming a part of the disclosure. For a better understanding of the invention, its operating advantages, specific objects attained by its use, reference should be had to the drawing and descriptive matter in which there are illustrated and described preferred embodiments of the invention.
REFERENCES:
patent: 4405092 (1983-09-01), Sybertz et al.
patent: 3505077 (1987-01-01), None
Kueffner Friedrich
Pallman Maschinenfabrik GmbH & Co. KG
Rosenbaum Mark
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