HK1080525B - Hinged tooth for a cutting wheel, cutting wheel and trench cutter - Google Patents

Description

Articulated cutting tooth, cutting wheel and ditching machine of cutting wheel

Technical Field

The present invention relates to an articulated cutting tooth for a cutting wheel, and more particularly to an articulated cutting tooth including a pivot support, a cutting tooth support, and a rotating arm.

Background

Such an articulated cutting tooth is disclosed in european patent EP 0291027B 1, which also belongs to the applicant. In trenchers where the cutting wheel is arranged laterally of the support housing, the problem arises that the soil immediately below the support housing cannot be moved directly by the cutting wheel. Thus, european patent EP 0291027B 1 suggests that the cutting teeth near the supporting housing are hinged to the cutting wheel. By some kind of cam rotation, the articulated cutting tooth can be swung into the area under the cutting housing, displacing the soil in this area, while further swinging of the cutting wheel causes the articulated tooth to swing back again, so that the cutting tooth does not damage the support housing.

For functional reasons and the inclination required thereof, the articulated cutting teeth are exposed to considerable forces and stresses, especially in the case of more compact soil or rock needs to be dug out of the ground. Known articulating cutting teeth exhibit significant wear and may fail prematurely, for which reason early replacement is often required. However, not only will replacing the articulated cutting teeth result in considerable downtime and expense for the high capital-invested trencher, but the articulated cutting teeth are expensive because they require the provision of pivot bearings and wear resistance.

Disclosure of Invention

It is an object of the present invention to provide an articulated cutting tooth with an improved stable shape, while being easy to manufacture.

This object is achieved by the preferred embodiments of the present invention.

The invention provides an articulated cutting tooth for a cutting wheel, comprising: a pivot support pivotally supporting a pivot shaft, the pivot shaft being located in the insertion hole of the cutting wheel; a cutting tooth support extending from the pivot support; a pivot arm extending from the pivot support in a direction opposite the cutting tooth support. The articulated cutting tooth according to the invention is characterized in that the three parts pivot support, cutting tooth support and swivel arm are designed together as a one-piece support. The articulating cutting teeth may be manufactured by casting or forging, although the preferred method of manufacture is by gas cutting a sheet of metal. The single piece pivot support and articulating tooth single arm embodiment has improved stability compared to the welded construction embodiment, while reducing manufacturing costs.

The preferred embodiment of the invention is based on the fact that the cutting tooth support is provided with a receiving portion in which hardened cutting teeth are releasably mounted. Soil-cutting teeth made of a special hardened material can be inserted into the single-piece support. For connection to the support, conventional forms or force-locking connection means and connection methods can be used.

A further advantage of the present invention is that there is a taper on the cutting tooth support between the pivot support and the receiving portion of the cutting tooth. The taper results in increased resilience of the projecting cutting tooth support, allowing the tapered portion to absorb bending loads, and the pivot support to release therefrom. Furthermore, the tapering also allows the articulated cutting tooth to improve its pivoting towards the cutting housing.

In principle, the pivot bearing can be designed as a single bearing hole, which can be formed on the bearing by gas cutting or drilling. However, in order to increase the elasticity of the pivot bearing, it is desirable according to the invention for the pivot bearing to comprise at least two mutually spaced bearing walls, which are provided with coaxial bearing holes. The support wall is made by forming a groove in a single piece support. The bearing holes can likewise be produced by gas cutting or drilling.

A further preferred embodiment of the invention is based on the fact that a part of the swivel arm is provided with a stop. The stop is adapted to cause the rotating arm to contact the cutter wheel receptacle with the hinged tooth supported in the cutter wheel receptacle. By this stop, the maximum swing angle with respect to the support housing is limited. The stop is made of a highly wear resistant material because the hinged teeth apply considerable pressure to the stop in the event of surface soil exposure during operation.

A further solution to the above object is based according to the invention on the fact that the wear plate is removably and replaceably supported on the swivel arm. The wear plate acts as a cam follower to establish contact of the articulating teeth with the rotating crown located on the cutting housing so that the moment and deflection range of the articulating teeth can be determined as a function of the rotational position of the cutting wheel. Unlike previous stops, wear plates exhibit considerable sliding friction for functional reasons. Accordingly, the wear plate preferably comprises a lubricating alloy, including for example bronze or brass. The wear plates can be manufactured separately, resulting in a reduction in the manufacturing costs of the articulated teeth. Within a certain degree of friction, the wear plates can be replaced quickly and inexpensively, while the bearing of the articulated tooth remains fixed to the cutting wheel.

However, according to the invention, the wear plate is preferably threadedly attached to the rotatable arm. The threaded connection can be manufactured in a very cost-effective manner and can be easily unscrewed and retightened.

In another embodiment of the invention, guide slots are preferably provided between the rotor arms and the wear plates, such as dovetail guide slots, which allow for quick and fine positioning of the wear plates on the articulated cutting teeth. As a result, maintenance time and costs can be further reduced. According to the invention, a reduction of wear plate material is achieved in that the wear plates are designed in a kidney-shaped manner.

In this respect, it is desirable according to the invention that the wear plate is designed with a chamfer at the side portions. The ramp may be straight or curved to allow smooth contact with the rotating crown to allow the hinged teeth to rotate out and back while avoiding any rocking. This has a positive effect on the working life of the articulated tooth.

Basically, the articulated tooth according to the invention can be used for various cutting wheels. However, a preferred use is in trenchers, such as trenchers for creating a retaining wall or a cutting wall for foundation work.

Drawings

The invention will now be described in detail by way of preferred embodiments, which are schematically illustrated in the drawings, in which:

FIG. 1 is a schematic view, partially in section, of an articulating cutting tooth on a support housing according to the present invention;

FIG. 2 is a plan view of an articulating tooth according to the present invention;

FIG. 3 is a side view of the articulating tooth of FIG. 2;

FIG. 4 is a partial cross-sectional view of the articulating tooth according to section A-A of FIG. 2; and

fig. 5 shows a perspective view of the wear plate of the articulated tooth according to the invention.

Detailed Description

Referring to fig. 1, there is shown the arrangement and function of an articulating cutting tooth 10 according to the present invention located in a support housing 5 of a trencher. Rotatable cutting wheels, which are not shown in the figures for the sake of simplicity, are provided on both sides of the bearing housing 5. On the side of the cutting wheel facing the support housing 5, a pivot 18 is provided, on which the articulated tooth 10 is pivotally supported in a known manner. The pivoting of the articulated tooth 10 is predetermined by a pivoting protuberance 7 fixed to the support shell 5, along which the articulated tooth 10 can slide. In fig. 1, the hinged teeth are shown rotated out of position to move the soil material beneath the support housing 5. The structure and function of the hinged teeth 10 will be described in more detail in connection with figures 2 to 4.

The hinged tooth 10 has a one-piece body 11 in which a pivot support 12 is provided to accommodate a pivot shaft mounted to a cutting wheel socket. As can be seen from fig. 4, two support walls 14 are designed to serve as pivot supports 12, which are separated by a slot 15, on which support holes 16 are drilled. The two bores 16 are coaxially aligned with each other and, if desired, a pivot 18 can be inserted into the sliding sleeve so that the articulated tooth 10 is pivotally supported. In order to accommodate the cutting tooth 24, which is schematically shown in the figures, a so-called cutting tooth support 20 is designed in the body 11, which is provided with two accommodating portions 22 into which the cutting tooth can be inserted. To improve the resiliency and better pivot the hinged teeth 10, the taper 26 is designed to be located between the pivot support 12 and the cutting tooth support 20 of the body 11, giving the body 11 a full hourglass shape.

A so-called swivel arm 30 extends from the support portion 12 in a direction substantially opposite to the cutting tooth support 20, which is also integral with the main body 11. A generally waist-shaped wear plate 34 is releasably and replaceably connected to the free end of the rotor arm 30 by a threaded connection 36. The wear plate 34 will be described in more detail below with reference to fig. 5.

The enlarged view of fig. 5 shows the waist-shaped front surface 38 of wear plate 34 with a chamfer 42 that is flanked by a central portion 40. The ramp 42 serves to provide a smooth and non-oscillating sliding movement of the wear plate 34 along the rotatable ridges 7 on the bearing housing 5.

The guide slots 44 are shown schematically at the rear face away from the wear plate front face 38 to allow easy and accurate positioning of the wear plate 34 to the articulated teeth 10. Further, behind the upper part, two threaded holes 46 are schematically shown, by means of screws fixing the wear plate 34 to the main body 11. In order to prevent wear and to ensure reliable stability, a material deposit 48 is provided in the portion of the threaded bore 46.

Claims (12)

1. An articulating cutting tooth of a cutting wheel, comprising:

a pivot support capable of pivotally supporting a pivot shaft, the pivot shaft being located within the receptacle of the cutting wheel;

a cutting tooth support extending from the pivot support;

a pivot arm extending from the pivot support in a direction opposite the cutting tooth support;

wherein the three parts pivot support, cutting tooth support and swivel arm together are designed as a one-piece support.

2. The articulating cutting tooth of claim 1 wherein said cutting tooth support is provided with a receiving portion in which a hardened cutting tooth is releasably mounted.

3. The articulating cutting tooth of claim 1, wherein there is a taper on said cutting tooth support between said pivot support and said receiving portion of said cutting tooth.

4. The articulating cutting tooth according to claim 1 wherein said pivot support comprises at least two spaced apart support walls, said walls having coaxial support apertures.

5. The articulating cutting tooth of claim 1 wherein a portion of said rotating arm is provided with a stop.

6. The articulating cutting tooth of claim 1 wherein a wear plate is removably and replaceably supported on the rotating arm.

7. The articulating cutting tooth of claim 6 wherein said wear plate is threaded to said rotating arm.

8. The articulating cutting tooth of claim 6 wherein a guide slot is provided between the rotating arm and the wear plate.

9. The articulating cutting tooth as claimed in claim 6 wherein said wear plate is designed as a waist.

10. The articulating cutting tooth as defined in claim 6 wherein the lateral portion of the wear plate is designed with a chamfer.

11. A cutting wheel comprising at least one articulating cutting tooth of claim 1.

12. A trencher provided with at least one cutting wheel as claimed in claim 11.