AU633615B2 - Traction tooth for cutting wheels - Google Patents

Description

The invention relates to a cutting wheel, such as a blade or bucket wheel, underwater cutting wheel or the like comprising a plurality traction teeth, whereby the cutting wheel is equipped with several blades fitted at the periphery which are equipped with cutting teeth in a receiving area and the traction teeth are located on at least two blades in such a way that each traction tooth is attached unilaterally directly on a respective appropriate blade back, adjacent a cutting tooth.

DE-OS 38 34 787 shows a blade with drills especially for bucket wheel excavators. Each drill is pivotally connected with the blade, whereby the drill is inserted pivotally into a holder in a support arm. This support arm is attached to the blade on one of its ends, whereas the other end is connected to the blade via two connectors. The support arm consists of a profile having transverse plates with bores for connection bolts, as well as of a clamp which is located on the protruding end of the profiles. The holder is formed by two flat profiles which are connected by two flat transverse spars.

The disadvantages of the prior art are primarily in that an expensive mounting support for the erection of the drill has to be made, whereby the drill itself is not connected directly to the blade. This construction on the one hand necessitates a high material and cost expenditure and on the other hand runs the danger that because of the lever arms between the blade's back and drill and forces connected therewith, which attach the blade's back, damage to the mounting support or to the drill itself can occur, which can possibly lead to an early breakdown of the drill. From US-A 2,979,838 the blade wheel of a blade wheel excavator is known which has several wheels on its periphery which in turn are equipped with cutting wheels in a receiving area. Between the single cutting wheels further wheels (traction teeth) are located which are firmly connected to the blade's back, in the area of one of their own ends and held in guiding elements. The disadvantage of this execution is that, because of the rotational movement of the blade wheel relatively high component forces are exerted onto the protruding wheels or traction teeth, whereby these, since they cannot move have a relatively low edge life.

This invention has the task, based on US-A 2,979,838 on the one hand, of improving on the latest development such that the traction teeth can move and on the other hand to create the possibility of chipping very hard and brittle material into small pieces whereby the traction teeth are preferably produced as a common part with the smallest possible manufacturing costs.

The present invention proposes movable traction teeth which are pivotable around an axis, whereby a pivot arm or bearing of each traction tooth is formed by a projection which protrudes through a respective recess in the area of a blade's back and which projection is lockable against removal from the blade.

Advantageous embodiments of this invention are described in relation to the drawings. This invention is not only useful on bucket wheels in open-cast mining, but there is also the possibility to use it for instance in brown coal mining under water, with a specially laid out underwater cutting wheel.

In contrast to the prior art the inventive characteristics make it possible to move the pivotal traction tooth directly into the area of the blade's back, whereby further holding elements, connected to the blade's back, are not necessary. Therefore, it is possible to economically machine very hard and brittle material into little pieces, without the normal wear and tear on the traction teeth, which is common on such known excavator teeth.

The advantages of the invention are mainly that each traction tooth can be independently adjustable to each new rotational speed, whereby the best possible tooth position can be maintained. This constantly changing tooth position gives the most economical tooth wear and tear at optimum cutting and minimal drive force.

The traction tooth pre-cuts the next depth, through its precise position on the blade's back, and therefore makes it easier for the blade teeth to loosen this layer and to fill the blades or buckets. Because of the best lay-out of the traction tooth and the blades, respectively, very fine material is achievable, which can be moved to a transport belt without any problems; it is not even necessary to make use of further interim crushing devices.

Each traction tooth is preferably located on a blade's back in such a manner that the lips wear and tear of the bucket wheel (open-cast mining) is avoided on each blades as much as possible. For this purpose, a traction tooth is envisaged which is locatable centrally or off-centre on each blade's back. The precise position, however, is dependent on the material to be machined. The traction tooth itself can be manufactured as a one-piece casting so that as compared to the prior art, a considerably cheaper alternative can be achieved.

Preferred uses in open-cast mining are seen for the machining of hard and brittle materials, i.e. chalk. The invention will now be described by way of example with reference to the accompanying drawings, in which:- Fig. 1: in a diagrammatic side elevation of a bucket wheel with blades and traction tooth, for open-cast mining; Fig. 2: is an enlarged part sectional view of a blade of the bucket wheel of Fig. 1 showing a traction tooth; and Fig. 3: is a plan view of Fig. 2 Fig. 1 shows in a schematic way a bucket wheel 1, which can be used for open-cast mining, especially for the loosening and carrying of chalk-and quartz containing rock. Each of the blades or buckets 2 has a material receive opening 3, around which cutting teeth 4 are positioned. On the blade's back 5 of each blade 2, a one-sided pivotal traction tooth is located in the vicinity of cutting teeth 4. The leading edge 7 of the traction tooth 6 is at a larger radius on wheel 1 than that of the cutting teeth 4. The pivoting axis 8 of each traction tooth 6 is machined to the direction of the resultant cutting of the bucket wheel 1. Each traction tooth 6 is hinged without any holding or guiding elements directly onto the blade's back 5 in the area 9 beneath its respective cutting tooth 4.

Fig. 2 and 3 show an enlarged blade 2 in a side view (Fig. 2) and in the plan view (Fig. Shown are cutting tooth 4 and traction tooth 6. The receiver area 10 for cutting tooth 4 extends in the direction of the blade's back and is used for supporting the area 11 of traction tooth 6. As can be seen, especially from Fig. 3, the hinged area 13 of traction tooth 6 is moved, outside of the blade's middle (longitudinal axis 12') on the blade's back. To do this, a through-bore 15 is made in the area of the cutting teeth through to the blade interior. This through-bore serves to take up a flange or lug 14 (bolt, shaft butt, or similar), which is attached to traction tooth 6 in its support area. In the blade's interior, lug 14 is held in place by a welded-on disc 16, in such a manner, that a lowest possible flexibility in direction of pivoting axis 8 is permitted, and whereby the rotating movfnent around the pivoting axis 8 can occur without difficulty. Traction tooth 6 has a bulged profile in its hinged area 13, which tapers towards edge 7, whereby the cross section of traction tooth 6 is approximately right-angled to acute-angled. Because of this freedom of movement angle each traction tooth 6 is enabled to independently adjust itself to various circumferences and pivoting speeds and thereby achieve a best tooth position regarding the material to be machined. Each traction tooth 6 pre-cuts, via its special axial lay out (longitudinal axis 12') on the blade's back 5, the next layer of material and thereby facilitate the loosening of the pre-ripped layer to be taken into blades 2. On each extension 10, fastening elements 17 are provided to take up the chain discs 18 which form the blade's back 5 and which are only partially indicated here.

It will be appreciated by persons skilled in the art that numerous variations and/or modifications may be made to the invention as shown in the specific embodiments without departing from the spirit or scope of the invention as broadly described. The present embodiments are, therefore, to be considered in all respects as illustrative and not restrictive.

Claims (6)

1. A cutting wheel, such as a blade wheel, underwater cutting wheel or the like, comprising a plurality of traction teeth, whereby the cutting wheel is equipped with a plurality of blades fitted at the periphery of sand wheel which is equipped with cutting teeth in a receiving area, said traction teeth being located on at least two blades in such a way that each traction tooth is attached unilaterally directly on a respective blade back, adjacent a cutting tooth, characterized in that the traction teeth are pivoted about respective pivoting axes, whereby the pivot of each traction tooth is formed by a projection protruding through a respective recess in the area of a blade's back and which projection is lockable against removal from the blade.

2. A cutting wheel as claimed in claim 1, characterized in that there is an extension of the receiving area supporting the respective traction tooth

3. A cutting wheel as claimed in claim 1 or 2, characterized in that the traction tooth is located outside the blade's longitudinal axis on the blade back.

4. A cutting wheel as claimed in any one of claims 1 to 3, characterized in that each traction tooth in the area of its pivot, as shown in plan view, is wider than its blade.

A cutting wheel as claimed in any one of claims 1 to 4, characterized in that the leading edge of each traction tooth is approximately perpendicular to the leading cutting tooth edge of its respective blade.

6. A cutting wheel as claimed in any one of claims 1 to characterized in that the free end of each projection is fitted with a welded on disk to prevent removal from the blade. ABSTRACT Proposed is a traction tooth for cutting blades, like blade wheels, underwater cutting wheels or the like, pivotably arranged in the region of several blades fitted at the periphery of the cutting wheel. The displacement of each traction tooth takes place unilaterally and without any other guide and holding components directly at the back of the appropriate blade. The pivoting axis of the traction tooth can be adjusted in the direction of the resultant cutting speed of the wheel. The traction tooth is in one piece and has a right-angled to acute-angled cross-sectional shape.