Tooth system

A tooth system for use in an earthmoving device, includes a tooth and an adapter onto which the tooth is mounted in a detachable fashion, the tooth including a longitudinally extending tooth web, a longitudinally extending tooth base and a longitudinally extending tooth head at a distance from the tooth base, the tooth base and tooth head also extending transversely with respect to the web. The adapter includes an adapter base intended to be fixed onto an earthmoving device, such as onto the teeth bars of a draghead, and an adapter head, a longitudinally extending undercut cavity being defined between the adapter base and the adapter head, wherein the tooth base is slidably fitted within the undercut cavity and wherein the adapter head is slidably fitted between the tooth base and the tooth head for mounting or dismounting the tooth with respect; to the front end of the adapter.

BACKGROUND OF THE INVENTION

The invention is related to a tooth system for use in an earthmoving device, such as a dredging or mining device, comprising a tooth and an adapter onto which the tooth is mounted in a detachable fashion, said tooth comprising a longitudinally extending tooth web, a longitudinally extending tooth base and a longitudinally extending tooth head at a distance from the tooth base, said tooth base and tooth head also extending transversely with respect to the web, said adapter comprising an adapter base which is to be fixed onto an earthmoving device, such as onto the teeth bars of a draghead, and an adapter head, a longitudinally extending undercut cavity being defined between the adapter base and the adapter head, wherein the tooth base is slidably fitted within the undercut cavity and wherein the adapter head is slidably fitted between the tooth base and the tooth head for mounting or dismounting the tooth with respect to the front end of the adapter, said adapter comprising at least one zone which faces a correspondingly shaped zone of the tooth.

DESCRIPTION OF THE RELATED ART

Such a tooth system is known from WO2005/005737. Said prior art tooth system is aimed at providing a reliable connection between the tooth and the adapter. Furthermore, the system should allow for a quick replacement of the tooth. The system can for instance be used in connection with dredging operations, in which case a number of adapters, each carrying a tooth, is mounted on the drag head of a dredger. In service, while carrying out dredging operations, both the teeth and the adapters are exposed to the influences of the materials which are being cut, such as rock, stones, sand and the like. These materials exert considerable forces on the teeth and also on the adapter, leading to wear of the tooth excavating part of the teeth, which therefore have to be replaced from time to time. However, it appears that the adapters also may suffer from considerable wear. This poses a problem in that said adapters in some cases are fixedly connected to e.g. the teeth bars of a draghead, such as by welding. In other cases, the adapters are fixed releasably.

The replacement of adapters is therefore much more cumbersome than the replacement of the teeth, which indeed have expressly been carried out for easy replacement. Worn out adapters however have the disadvantage that their function of firmly holding the teeth in place, is adversely influenced. The teeth in question will no longer be supported in an adequate way, which leads to a certain play of the tooth with respect to its adapter. These phenomena of play however further impair the proper functioning of the cutter head. Thus, after some time such a worn out adapter should be replaced as well, which means removing the welded connection, and welding replacement adapters onto the draghead.

SUMMARY OF THE INVENTION

The object of the invention is therefore to provide a tooth system of the type described before, which provides for a better support of the tooth with respect to its adapter, as well as for a better protection of the adapter against wear. This object is achieved in that at least one pair of correspondingly shaped facing zones of the adapter and the tooth comprises a stepped configuration.

The advantages of the stepped configuration of the facing zones of the adapter and the tooth according to the invention are twofold. First of all, such stepped layout of the facing zones represents a stable support for the tooth with respect to the adapter. The stepped zones represent separate areas for supporting the tooth, suitable for withstanding forces and bending moments exerted on the tooth. Moreover, such separate areas offer the possibility to accommodate any imperfections in the facing surfaces without impairing the stability of the tooth, which imperfections may result from the manufacturing process of the components in question.

Furthermore, the stepped configuration enables an easy replacement of the tooth with respect to the adapter. In this connection, preferably the stepped configuration may define a wide cavity section and a narrow cavity section of the adapter, whereby the wide cavity section borders the front end of the adapter. Alternatively or additionally, the stepped configuration may define a thin adapter flange section and a thick adapter flange section, whereby the thin adapter flange section borders the front end of the adapter. In particular, such stepped configuration comprises several lands and recesses of the pair of facing zones, whereby each time a pair of a land of the one component, and a recess of the other component are facing each other. Preferably, the adapter has at least an adapter recess bordering the front and thereof and at least an adapter land at the end of the adapter recess opposite the front and, in which case the tooth has at least a tooth land opposite the adapter recess and at least a tooth recess opposite the adapter land.

The recesses may have a larger longitudinal dimension than the corresponding lands. In such a layout, the facing recesses will overlap each other over a certain extent, thus providing a gap in the area of the overlap. Such layout provides advantages as to the accommodation of imperfections as addressed before.

In the prior art tooth system, the adapter head comprises opposite adapter flanges which enclose a slit at their facing edges and which delimit the undercut cavity, the web extending through the slit. In such an embodiment, the tooth head faces the adapter flanges. Furthermore, the tooth web is positioned in a slit defined between the opposite adapter flanges, the tooth base comprising tooth base flanges extending on opposite sides of the tooth web, each tooth base flange being positioned opposite a corresponding adapter flange. A firm additional support of the tooth with respect to the adapter is now obtained by these pairs of mutually cooperating pairs of a tooth head flange, an adapter flange and a tooth head flange.

Preferably, the pairs of a tooth base flange and a facing adapter flange each have facing flange surfaces which are oriented at equal but opposite angles. In this connection, the slanting tooth base flange surfaces each comprise a tooth base flange recess, which tooth flange recess faces a corresponding adapter flange inner land. Furthermore, the slanting tooth base surfaces each comprise a tooth base flange land which faces a corresponding adapter flange inner recess.

Preferably, the tooth head comprises two opposite tooth head flanges which are on opposite sides of the web. The tooth head flanges each comprise a tooth head flange land which faces a corresponding adapter flange outer recess. Additionally, the tooth head flanges each comprise a tooth head flange recess which faces a corresponding adapter flange outer land.

In a known way, the tooth comprises a front cover which is known per se. In the tooth system according to the invention, said front cover extends transversely with respect to the tooth web and faces the front end of the adapter. Preferably, the front cover of the tooth abuts the front end of the adapter so as to avoid clenching of the tooth with respect to the adapter which would prevent replacement of the tooth. In this connection, a further improvement of the tooth system according to the invention can be obtained in case the tooth head and the front cover are connected to each other, for instance at a sharp angle. The combined effect of the interconnected tooth head and front cover provides an advantageous shielding of the areas of the adapter which would otherwise be prone to the abrasive influences of the materials. Furthermore, the interconnected tooth head and front cover provide an additional stabilizing effect with respect to the correspondingly shaped adapter, the front of which is snugly surrounded by said combined tooth head and front cover.

Locking means may be provided which comprise a locking member positioned at an end of the undercut cavity of the adapter, and a locking part at the tooth base end facing the locking member. The locking member and the front cover are at opposite ends of the adapter.

For further improving the support of the tooth with respect to the adapter, the undercut cavity of the adapter may be tapered from a relatively wide front end to a relatively narrow back end, the tooth base having a corresponding taper. The front cover is at the relatively wide front end of the adapter and the locking element is at or near the relatively narrow back end of the adapter.

The tooth head covers the outwardly facing surfaces of the adapter to a large extent, which means that the adapter is largely shielded from the abrasive influences of the materials which are being cut loose. The tooth head itself will of course still be subjected to these wear phenomena, however having regard to the fact that the tooth, of which the to said forms part, is to be replaced from time to time anyway, such wear is quite acceptable.

DESCRIPTION OF THE PREFERRED EMBODIMENT

The tooth system according to the invention, as shown in the figures, comprises a tooth1connected to the adapter2. Said tooth1comprises a tooth base4, as shown inFIGS. 4,10and11, as well as a tooth excavating element5with a cutting edge3. Furthermore, the tooth comprises a tooth web6which extends between the base4and the tooth head15. Said tooth head15is located opposite the tooth base4. The adapter2comprises an adapter base7having two opposite upstanding walls8which support the adapter head29. The adapter head29is provided with facing adapter flanges9. Said adapter base7, upstanding walls8and adapter head29with adapter flanges9define an undercut cavity10which by means of slit11opens out at the position of the adapter flanges9.

As shown inFIGS. 1-5, the tooth base4of the tooth1has been slid into the undercut cavity10of the adapter2. At the same time, the tooth web6of the tooth1has been accommodated in the slit11of the adapter2. As the tooth1comprises a front cover12, opposite the front end13of the adapter2, said sliding motion of the tooth1with respect to the adapter2is limited as soon as the front end13and the front cover12, come into contact. With the aim of further improving the locking of the tooth1with respect to the adapter2, the front end13of the adapter2comprises indentations31, and the facing surface of the front cover12comprises protrusions30which are accommodated within said indentations31. At the end of the adapter2opposite the front end13, locking means14are provided for locking the tooth1with respect to the adapter2. Said locking means14comprises a locking element32connected to the adapter2, as well as a hook33forming part of the tooth1(seeFIG. 4).

As mentioned before, the tooth1has been provided with a tooth head15. Said tooth head15is connected to the front cover12, and comprises two tooth head flanges16,17on opposite sides of the web6. Similarly, the front cover12comprises two flanges18,19, also on opposite sides of the web6. The tooth head flanges16,17each bear on a corresponding adapter flange9. Said tooth head15, in combination with the front cover12, protects the adapter2with respect to the abrasive action of the materials which are being cut by the tooth system in question.

With the aim of improving a stable support of the tooth1with respect to the adapter2, the tooth head flanges16,17each comprise a tooth head flange recess22at their rearward end, as well as a tooth head flange land21at their forward end adjoining the front cover12. Similarly, the adapter flanges9comprise adapter flange outer lands26at their rearward end, as well as adapter flange outer recesses28at their forward end. As a result, the tooth head flanges16,17are stably supported with respect to the corresponding adapter flanges9through these pairs of tooth head flange lands21and adapter flange outer recesses28(see also the cross section ofFIG. 6), as well as through the pairs of tooth head flange recesses22and adapter flange outer lands26. (see also the cross-section ofFIG. 8).

The tooth base4comprises tooth base flanges24at opposite ends of the web6. These tooth base flanges24bear against the inner side of the adapter flanges9. To that end, the adapter flanges9comprise an adapter flange inner recess23(see also the cross-section ofFIG. 8) and an adapter flange inner land20(see also the cross-section ofFIG. 9). Furthermore, the tooth base flanges24comprise a tooth base flange land27and a tooth base flange recess25. By means of the pairs of an adapter flange inner land20and a tooth based flange recess25, and the pairs of an adapter flange inner recess23and a tooth base flange land27, the stable support of the tooth1with respect to the adapter flanges9of the adapter2is further improved.

The above pairs of lands and recesses are at a distance from each other, separated by gaps36and37as shown inFIG. 4. Thereby, any irregularities in the facing surfaces can be accommodated without however impairing the support stability.

As will be clear from the top view ofFIG. 13and the sectional view ofFIG. 4, the internal cavity10of the adapter2has a tapering shape, running from a relatively wide cross-section at the front end13towards the back end. Similarly, the tooth base4has a tapering shape so as to snugly fit within said internal cavity10.

A wear plate35is positioned on the adapter base7, as shown inFIGS. 4,9,15and16, and mounted by means of bolts34. This wear plate protects the adapter base from wear, and can be easily replaced in case said plate has been worn down by multiple replacements of the tooth.

TheFIGS. 18-20show an example of the application of the tooth system according to the invention in a suction cutter head. Generally the cutter head comprises a suction chamber housing38having a suction opening41and connected to the suction mouth40which is to be connected to a suction tube leading to the bin of a dredging vessel (not shown). Furthermore, a pressure conduit39is provided for supplying the jet nozzles with pressurized water used in the cutting process. The adapters1of the tooth system according to the invention are mounted on the suction chamber housing near the suction opening41, whereby the teeth2are positioned in such a way that they can exert a cutting action on the bottom of a body of water while the suction cutter head is dragged (to the right in the figures) over said bottom.

LIST OF REFERENCES

3tooth cutting edge

6tooth web

8upstanding adapter wall

12tooth front cover

13adapter front end

18tooth front cover flange

19tooth front cover flange

20adapter flange inner land

21tooth head flange land

22tooth head flange recess

25tooth base flange recess

26adapter flange outer land

27tooth base flange land

36gap at tooth head

37gap at tooth base

38suction chamber housing