WO1999045211A1

WO1999045211A1 - Tooth arrangement

Info

Publication number: WO1999045211A1
Application number: PCT/SE1998/000366
Authority: WO
Inventors: Kjell Karlsson
Original assignee: Componenta Wear Parts Ab
Priority date: 1998-03-02
Filing date: 1998-03-02
Publication date: 1999-09-10
Also published as: AR018138A1; AU7087698A; ZA991668B

Abstract

Tooth systems are used with, amongst other things, excavators so as to increase the working possibilities of the dipper. The system consists of a retainer (2) and a tooth part (1) with a recess (4) to enable combination with the retainer (2). When the retainer and the tooth part are joined with each other, there is a transversal aperture (5, 6, and 10) through both the parts (1 and 2) intended to receive a locking element (3). The purpose of the present invention is to improve the locking between the retainer (2) and the tooth part by providing the locking element with cog segments on two opposite sides intended to concur with cog segments in the apertures (5 and 6).

Description

TOOTH ARRANGEMENT

AREA OF THE INVENTION

The present invention relates to a tooth system. Such systems are used on excavators, amongst other things, in order to fill a dipper as efficiently as possible.

A tooth system consists of three parts, namely a tooth part with a recess, designed to receive a retainer, which is attached to the tool on which the tooth is to be used. When the tooth part and retainer are joined, there is a transversal aperture through both these units. A locking element is introduced into this aperture. There are a number of different types of locking elements and apertures designed to fasten the tooth as well as possible and to ensure that the service life of the tooth system is as long as possible.

A vast number of tooth systems are known and most of these have turned out not to be so durable because of the difficulties in achieving an efficient locking between tooth and retainer.

BACKGROUND OF THE INVENTION

As the preceding section makes clear, the purpose of the present invention is to create a tooth system that has as long a service life as possible. How this is carried out is explained in the following section.

BRIEF DESCRIPTION OF THE INVENTION

The desired longer service life is achieved by a locking mechanism that is roughly rectangular and has a top surface and a bottom surface that preferably are at an angle with each other. The two surfaces are not level but have some degree of configuration. The top surface and the bottom surface of the locking element are intended to concur with the aperture created by the two apertures in the tooth part and the central aperture in the retainer. As the locking element is rectangular, the aperture must also be rectangular and the top and bottom sides of the aperture have surfaces that concur with the surfaces of the locking element in such a way that, when the locking element is introduced into the aperture, its surfaces will concur with the upper and lower aperture surfaces of the tooth-part. The apertures in the tooth walls are aimed roughly towards the pointed edge of the tooth. The surfaces of the aperture and the locking element are such that, when they concur with each other, they are in complete contact with each other. The surfaces are such that relative transposition is possible between the aperture and the locking element The most suitable surface to use for the aperture as well as for the locking element is a cog-shaped segment surface, where a cog segment in the aperture surfaces positioned one over the other concurs with a cog segment in the locking element. The locking element has a cog segment with a width that can be as wide as the length of the locking element. It would also be possible to have cog segments only at each end of the locking element. A suitable shape for a cog is with one completely transversal side and one inclined side. Having cogs of this type, enables the locking element and the tooth part to be repositioned one cog segment at a time in relation to each other and, because of the straight cog surface, the tooth part cannot move outwards.

To enable repositioning by one cog step, the locking element must be such that it incorporates two rectangular metal parts, the outer surfaces of which have cog segments as iong as the metal parts, which are parallel to each other and have between them an elastic parallelepipedic element, preferably made of rubber. A metal surface that is as long as the top and bottom parts of the locking element is fixed to one of the long sides of this elastic element. Stops, constituted by fillings in the respective cog spaces, can be provided in the tracks of the cog segments. This means that, when a locking element is introduced into an aperture through the tooth part and retainer, the locking element must be compressed so that the stop can get past the cog segment in the aperture of the tooth part and end up inside the cog element in the tooth part. In this way there is no possibility of the locking element leaving the aperture, as the stops on both sides block any axial movement

If a cog segment should be subjected to extraction forces, the elastic element is redistπbuted and compressed between the perpendicular and both the parallel metal parts, which may be of steel. Thus a servo force is achieved which presses both the parallel metal parts with great force into the cog segment, which with great clamping force prevents the tooth from falling off.

In accordance with the invention, the retainer has an external conical shape and the tooth part has a recess with an internal conical shape where the walls of the two cones are intended to concur with each other. It has been found advisable for the retainer to consist of two consecutive parts with different conicities, preferably with the greatest cone angle in the outer part of the retainer. Regarding the recess in the tooth part, there are, here as well, two consecutive parts with different conicities where, preferably, the cone angle is greatest in the inner part and the outer part has a smaller cone angle. In the transitions between conicities, the tooth part and the retainer have transitional sections that are not in contact with each other. The upper part of the recess in the tooth part should, preferably, have a difference in angle in relation to the retainer, whereby a pinching effect arises between the tooth part and the retainer. DESCRIPTION OF DRAWINGS

Ten figures are attached hereto, in which

Figure 1 shows a tooth part in perspective, Figure 2 shows a retainer in perspective,

Figure 3 shows the three component parts of a tooth system, namely tooth part, locking element and retainer, Figure 4 shows all three elements almost joined,

Figure 5 illustrates different conicities in the retainer as well as the tooth part,

Figure 6 shows a complete locking element

Figure 7 shows an exploded view of a locking element

Figure 8 shows an exploded view of a retainer,

Figure 9 shows the elastic constituent part of a retainer, and Figure 10 shows an element that can be either the upper or lower part of the locking element.

DETAILED DESCRIPTION

Figure 3 shows the component parts of a complete tooth system, namely a retainer 2, a tooth part 1 and a locking element 3. In Figure 1 a tooth part is shown and the rear part of the tooth part has a roughly rectangular cross section with four walls and a recess 4 for receiving a retainer. The recess is conical from the rear part to the front part and is divided so that the conicity angle for the first part of the recess, counted from its open end, is smaller than for the bottom part of the recess. The upper part of the recess can, furthermore, be somewhat deepened so as to be able to overcome different tolerances in the retainer. Opposite walls in the tooth part each have an aperture 5 and 6. The two apertures 5 and 6 are aimed towards the front part of the tooth and have approximately the same direction as the tooth itself. The aperture is oblong and thus has two long walls and two short walls. The long wails have been shaped as cog segments, where each cog has a preferably straight transversai part and an inclined, part, as shown in Figure 5.

Figure 2 shows a retainer which is intended to be joined in one way or another with its upper part to a suitable tool, joined, for instance, to the cutting edge of a dipper or some other implement. The retainer 2 has a bottom part 7 which is conical and a top part 8 which also is conical. The conicity angle is greater for part 8 than for part 7. Between the two conical parts there is an intermediate part 9, which is not intended to be in contact with the corresponding wall of the recess in the tooth 1 and which should have an angle that differs from the angles of the parts on each side of the intermediate part 9. The retainer also has an aperture going through it which is oblong and the axial length of which is shorter than the axial length of the tooth part

Figure 3 shows the three parts necessary for a complete tooth system, namely the tooth part 1, the retainer 2 and the locking element 3. The design of the locking element 3 is clearly shown in Figures 6, 7 and 8 as well as in Figures 9 and 10. The locking element consists of an upper and a lower metal part, which on their outer surfaces have cog segments of a width corresponding to the length of the parts 15 and 16. These two parts are attached, for instance through vulcanization, to the element 14, which consists of an elastic material, preferably rubber. A further metallic part 13, which has a level surface facing the elastic material 14 and a curved outer surface, is vulcanized onto the elastic material 14. it is apparent from Figures 8 and 10 that a unit with a cog segment has stops 25, 26, 29 and 30 at each end. These stops can be fillings in the bottom of the tracks of the cog segments. It is perhaps obvious that the cog segments very well can be positioned only at the ends of each metal unit 15 and 16 in accordance with Figure 7. The drawings show a locking element with only three cogs 19, 20, 21, 22, 23 and 24, but it should be obvious that the number of cogs is not limited to three. Instead, the number may be chosen so as to achieve the desired locking effect.

As the locking element has surfaces that are preferably completely transversal, it is possible to insert the locking element 3 into the aperture 5 only in one position, namely with the metal part 13 positioned downwards. Before the locking element 3 is inserted into the aperture 5, the retainer is introduced into the tooth part so that the apertures 5, 6 and 10 are aligned with each other. Figure 4 shows how the locking element 3 is inserted into the retainer 2 and tooth part 1. The locking element 3 will be compressed slightly when the stops are in the aperture wall 5. When the stops are positioned on the inside of the aperture wall 5, the elastic element will expand so that the cog-segment surfaces of the locking element and the corresponding surfaces on apertures 5 and 6 will be in contact with each other. By using cogs of the type shown in Figure 5, the tooth part 5 can be moved, in locked condition, onto the retainer 2 until the transversal parts of the cogs are in contact with each other, preventing any outward movement of the tooth in relation to the retainer. Through this arrangement the tooth part can be moved step by step so that the outer cone of the retainer comes into contact with the inner cone of the tooth part.

The present invention, based on a locking element with cog segments and corresponding apertures also with cog segments, enables greater durability for a tooth system and also axial movement of the tooth step by step towards the retainer 2.

Giving the retainer as well as the recess in the tooth part two different consecutive conicities achieves greater stability in the tooth system.

Claims

1. A tooth system consisting of a retainer in the shape of a male part intended to be attached to a working tool such as an excavator dipper, whereby the said male part concurs with an exchangeable tooth part which is fitted with a female part, where the retainer and the tooth part are each fitted with a transversal aperture, which apertures are intended to be aligned with each other and receive a locking element, such as a bolt, characterized in that the apertures (5 and 6) of the tooth part (1) and the locking element (3) are designed in such a way that the tooth part (1) can be pushed on to the retainer (2) in the axial direction and locked in different positions depending on tolerance values, where locking is secured by effecting relative movement between the apertures (5 and 6) and the locking element (3).

2. A tooth system as claimed in claim 1, characterized in that the aperture (10) of the retainer (2) and the apertures (5 and 6) of the tooth part (1) are of a conical character, the apertures (5 and 6) of the tooth part (1) having greater extension in the direction of the tooth part (1).

3. A tooth system as claimed in claim 2, characterized in that at least one wall of the aperture (5) in the direction of the tooth (1) itself has a non-level surface intended to concur with a surface of the locking element (3), both surfaces being designed in such a way that they can be brought into complete contact with each other in different axial positions.

4. A tooth system as claimed in claim 3, characterized in that the wall opposite the wall with a non-level surface is designed in an equivalent way, whereby both sides of the locking element (3) concur with both the opposite walls of the aperture (5 and 6 respectively) and are designed accordingly.

5. A tooth system as claimed in claim 3 or 4, characterized in t h a t the non-level surface of the locking element (3) has a preferably serrated cross section and the aperture (5 and 6 respectively) has a preferably serrated longitudinal section, which two preferably serrated elements are designed in such a way that their surfaces can be brought into complete contact with each other and moved in relation to each other one step at a time in the axial direction.

6. A tooth system as claimed in claim 5, characterized in that each cog has one preferably sloping part and one transversal part, such that retrograde motion by the tooth part is prevented when the transversal surfaces of two cogs are in contact with each other.

7. A tooth system as claimed in claim 6, characterized in that the cogs on the locking element may be of a width equal to the length of the locking element (3) or, alternatively, be provided only at the ends of the locking element.

8. A tooth system as claimed in claim 7, characterized in that a cog segment in a dip is provided with a stop (29 and 30), which may be in the form of a filling that, on insertion into the tooth system, will be positioned on the inside of an aperture (5) in the tooth part(1).

9. A tooth system as claimed in one or several of the preceding claims, characterized in that the locking element (3) consists of two long metal units (15 and 16), arranged on each side of an elastic parallelepipedic unit (14), preferably of rubber, the four units (13-16) being joined to each other and the metal elements ( 5 and 16), at least, being covered by a cog surface along their entire lengths or merely at both ends of them.

10. A tooth system as claimed in claim 9, characterized in that the parallelepipedic element (14) of elastic material is joined along one of its side wails with a metal unit (13) that is at right angles with the two other metal units (15 and 16), whereby the unit (13) is in contact with the front wall (31) of the aperture (10) in the retainer (2).

1 . A tooth system as claimed in one or several of the preceding claims, characterized in that the retainer (2) is of a conical design and the recess (4) in the tooth part (1) is of a conical design.

12. A tooth system as claimed in claim 11, characterized in that the retainer (2) is divided into two parts (7 and 8) where the inner part (7) has a smaller conicity angle than the outer part (8) and the tooth part (1) has two different conicities along its recess (4) where the inner part of the recess (4) has a greater conicity angle than the outer part of the recess (4).

13. A tooth system as claimed in claim 12, characterized in that the transitions between the two conicities in the retainer and in the recess (4) of the tooth part (1) are not in contact with each other.