EP3781319B1 - Striking tool and rotor fitted with same for a machine for crushing metal objects or rocky materials - Google Patents

Description

The invention relates to an impact tool for the comminution of metal objects or rock materials.

Impact tools of this type are also referred to as "impact hammers" and are used in machines for comminuting scrap metal, such as vehicle bodies intended for scrapping, or demolition or construction debris.

The striking tools, which are usually cast in one piece from an iron-based material or alternatively produced by forging or flame cutting a correspondingly shaped pre-product or as a welded construction, comprise a bearing section into which a bearing opening with an inner circumferential surface surrounding the bearing opening is formed, as well as a striking section that is in use is exposed to impact loads from contact with the material to be shredded. During use, a metallic axle is pushed through the bearing opening, on which the striking tool is then pivoted so that there is metallic frictional contact between the outer circumferential surface of the axle and the inner circumferential surface of the bearing opening of the striking tool.

Examples of such striking tools are in WO 97/05951 A1 and the brochure "Stahlwerke Bochum - Highly wear-resistant cast parts" from 2012, published by the applicant and available for download available at the URL http://stahlwerke-bochum.com/wpcontent/uploads/2015/07/swb_image_prospekt_d.pdf.

An example of a rotor for a shredding machine that can be equipped with impact tools of the type considered here is shown in FIG EP 1 047 499 B1 shown.

Such rotors rotating around an axis of rotation in use have several axles distributed at equal angular intervals around the axis of rotation, axially parallel to the axis of rotation, on which a larger number of hammer hammers are freely oscillating at a distance from one another. In its circumferential areas between the hammers, the rotor is usually covered with so-called "protective caps" which, like the hammers, are usually made of highly wear-resistant steel, mainly by casting, but alternatively also by forging, flame cutting or welded construction. The protective caps arranged next to the percussion hammers are mounted at a distance from the respective percussion hammer so that, on the one hand, the percussion hammer can freely perform its pendulum movement, but on the other hand, the gap that must be present between the respective protective cap and the associated percussion hammer in order to allow its pendulum movement allow, is as narrow as possible, in order to prevent metal or stone parts from penetrating the gap in question and the hammer from being blocked by material sitting in the gap during operation.

The centrifugal forces acting in vertically or horizontally rotating percussion tools of the type explained above, depending on the respective rotational speeds, are high and lead to heavy loads in the bearing opening, which particularly affects the inner circumferential surface of the bearing opening, which is exposed to direct metallic frictional contact with the axis of the rotor is. Dynamic load components lead to high voltage peaks.

Practical experience shows that the bearing opening becomes deformed with increasing service life and the associated increase in load changes to which the striking tool is exposed. In this way, not only is the bearing opening widened in the radial direction, but also rolling-out effects occur, by means of which material of the striking tool that delimits the bearing opening is displaced in the longitudinal direction of the bearing opening. In this way, thickenings, so-called "flanges", are formed at the frontal mouths of the bearing opening. These can grow so much that the width of the bearing section of the striking tool in its area adjoining the bearing opening increases beyond its original width.

This wear phenomenon can go so far that the gap between the striking tool and the protective caps positioned laterally next to it is closed by material pushed out of the bearing eye and the pendulum movement of the striking tool is blocked. Even if this does not occur, the lateral material displacement that occurs in practical use leads to increased wear of the axis on which the striking tools are mounted, as well as in the area of the transitions between the bearing opening and the respective end face of the striking tool or on the associated side surfaces of the adjacent protective caps against which the material displaced from the bearing opening rubs.

Against the background of the prior art explained above, the object was thus to create a striking tool in which the risk of excessive wear in the area of its bearing opening is minimized by simple means, even under high loads.

In addition, a rotor for a machine for comminuting metal or stone materials was to be created, in which an optimally long service life of the striking tools pendulum mounted on it is achieved with simple means.

With regard to the striking tool, the invention has achieved this object in that such a striking tool is designed according to claim 1.

A rotor for a machine for crushing metal or rock materials, in particular scrap, such as automobile bodies to be scrapped, or residual rock masses from building construction or demolition, is accordingly equipped with an impact tool according to the invention.

Advantageous refinements of the invention are specified in the dependent claims and, like the general inventive concept, are explained in detail below.

An impact tool according to the invention for the comminution of metal objects or rock materials is accordingly made from an iron-based material in accordance with the prior art explained at the beginning and comprises a bearing section in which a bearing opening provided for freely oscillating storage of the impact tool on a metallic axis with a bearing opening surrounding inner circumferential surface is formed, with metallic frictional contact between the outer circumferential surface of the axle and the inner circumferential surface of the bearing opening of the impact tool, as well as an impact section which is exposed to an impacting load during use due to contact with the material to be comminuted. According to the invention, a recess is formed in at least one section of the inner circumferential surface of the bearing eye, which is provided for receiving metallic material of the striking tool laterally adjoining the recess and displaced during use.

The at least one indentation, which according to the invention is molded into the inner circumferential surface surrounding the bearing opening, provides space in the area of the inner circumferential surface itself, into which the material of the hammer, which evades as a result of the compressive forces acting on the inner circumferential surface in practical use, can escape. In this way On the one hand, this prevents material which surrounds the bearing opening from being pushed laterally out of the bearing opening and leading to a thickening of the hammer and consequently to a narrowing of the movement gap between the relevant face of the hammer and the associated side of the adjacent protective cap. On the other hand, the compressive stresses are limited in the area of the inner circumferential surface of the striking tool delimiting the bearing opening, so that the material displacement is reduced and the risk of cracking or other damage, such as pieces of material breaking out and the like, is reduced. According to the invention, the indentation runs spirally around the bearing opening and / or completely delimits at least one circumferential area of the inner circumferential surface in the longitudinal and circumferential direction of the inner circumferential surface and / or two or more indentations are distributed in the inner circumferential surface of the bearing eye in the longitudinal direction of the bearing opening.

With the design of the inner circumferential surface of the bearing opening according to the invention, it is thus possible to effectively extend the service life of an impact tool for the comminution of materials which is exposed to the highest loads in practical use. Due to the structuring of the inner circumferential surface brought about by means of the indentation provided according to the invention, the geometry of the bearing opening is stabilized over the service life of the striking tool. Rolling out of the material is largely avoided and the surface tensions are reduced, with the result that factors that initiate cracks and possibly lead to damage to the striking tools are minimized.

In this case, the indentation provided according to the invention can be introduced into the inner circumferential surface in a particularly simple manner in terms of production technology. Thus, the depression can already be introduced into the inner circumferential surface during the casting of the striking tool by means of a suitably shaped casting core that depicts the bearing eye. However, it can also be produced by other manufacturing processes, such as, for example, by electroerosion or mechanical, in particular machining, processing.

In most practical applications, an impact tool according to the invention oscillates around the axis on which it is mounted, in each case only over a swivel range that is smaller than 360 °. In these cases it is usually sufficient when the indentation provided according to the invention is limited to the area of the inner circumferential surface in which high compressive stresses occur as a result of the centrifugal forces acting on the impact tool in use. This allows the less stressed area of the bearing opening to be designed in a different way, for example in the form of an enlargement of the bearing opening extending in the direction of the striking section, so that the bearing section of the striking tool is given expansion properties not only because of its material properties, but also because of its shape that protects it from the appearance of cracks and breaks.

The shape and the course of the indentation provided according to the invention are to be designed in such a way that the material displaced laterally in the area of the inner circumferential surface of the bearing eye during use is taken up as completely as possible by the indentations.

For this purpose, it can be useful to form a surface structure in the indented section of the inner circumferential surface of the bearing opening, in which at least one circumferential area of the inner circumferential surface is separated from an adjacent circumferential area of the inner circumferential surface by the indentation. As a result of the subdivision of the inner circumferential surface created in this way, the volume available for displacement that is present in the areas divided from one another is reduced, so that the potentially displaced amounts of material are also reduced.

The simplest possibility of such a subdivision consists in a recess running around the inner circumferential surface. For this purpose, the depression can be designed, for example, in the form of an annular groove encircling the longitudinal axis of the bearing opening.

The depression can each have the shape of a groove, whereby it goes without saying that regardless of which shape is provided for the depression, the transitions, corners and edges of the depression are each designed, in particular rounded, that the danger from there otherwise occurring notch effect is avoided.

In order to achieve a multiple subdivision of the inner circumferential surface into two or more separate circumferential surface areas, two or more depressions can be molded into the inner circumferential surface of the bearing eye in a distributed manner in the longitudinal direction of the bearing opening.

Another example of a depression that structures the inner circumferential surface in such a way that a circumferential surface area of limited extent is present between two adjacent sections of the depression is a depression that is formed into the inner circumferential surface in a spiral shape around the bearing opening.

The indentation in the inner circumferential surface of the bearing opening can also form a structure in which at least one circumferential surface area of the inner circumferential surface is completely delimited by the indentation in the longitudinal and circumferential directions of the inner circumferential surface. For this purpose, the depression can be designed in such a way that the peripheral surface area delimited by the depression is elliptical, circular, square or diamond-shaped. Of course, the indentation can be shaped in such a way that two or more circumferential areas of the inner circumferential surface are separated from one another.

Such a structure can also be formed by a plurality of groove-shaped depressions that cross one another and have different depths or widths.

In particular, with regard to the uniformity of the load to which the individual circumferential surface sections separated from one another by the recess in this embodiment are exposed in use, it can be advantageous if the relevant circumferential sections are evenly distributed over the inner circumferential surface of the bearing opening, through the recess in the inner circumferential surface that is, a regular structure is formed in which circumferential surface sections separated from one another are distributed in a regular arrangement on the inner circumferential surface.

As already mentioned, the shape and extent of the indentation provided according to the invention on the inner circumferential surface of the bearing opening of the striking tool according to the invention are to be selected so that they can accommodate as completely as possible the material that is potentially displaced during use and delimiting the bearing eye. For this purpose, it has proven useful if the depth of the recess measured in the radial direction starting from the inner circumferential surface is undertaken taking into account the hardness that is present in a layer near the surface, adjacent to the inner circumferential surface of the bearing opening when the impact tool is used, or is there in Ceases in the course of use. In this way, the influence of the properties of the material from which an impact tool according to the invention is made and the heat treatment that the impact tool undergoes in the course of its manufacture can be taken into account in order to optimally adapt its mechanical properties to the loads occurring during use.

An impact tool according to the invention can consist of a cast steel material in which, as a result of near-surface cold deformation, as occurs when using an impact tool according to the invention in the contact area between the inner circumferential surface of the bearing opening and the outer circumferential surface of the axis on which the impact tool oscillates, solidification and thus a solidification accompanying increase in hardness. It can also result in a Heat treatment to which the impact tool is subjected during its manufacture in order to set a maximum hardness in the area of its impact section and an optimized toughness in the area of its bearing section, resulting in decarburization and an associated decrease in hardness in a surface layer adjacent to the inner circumferential surface of the bearing opening.

In the latter case, in particular, it is advantageous if the depth of the indentation measured in the radial direction from the inner circumferential surface into the material of the striking tool is at least equal to the thickness of a surface layer adjoining the inner circumferential surface, the hardness of which is lower than the hardness of one of the surface layer adjoining core layer of the striking tool, which is delimited by the surface layer opposite the bearing opening. In practice, depressions that are 2 - 30 mm deep, for example, are suitable.

In order to ensure a sufficient load-bearing capacity of the inner circumferential surface of the bearing opening of a striking tool according to the invention despite the recess provided according to the invention, the recess should occupy a maximum of 50% of the inner circumferential surface of the bearing opening, the recess advantageously extending over at least 25%, in particular over at least 30% or at least one third the inner circumferential surface should extend in order to provide a sufficiently large receiving space for the displaced material of the impact tool in use. In this case, the "inner circumferential surface" which is not provided with a depression is used as a reference value for the percentage specification. In the case of a bearing opening with a circular inside diameter, for example, this is equal to a hollow cylinder surface, the diameter of which is equal to the inside width of the bearing opening.

If several independent depressions are provided, these can have different widths and depths. The depressions can be arranged at an angle of 10 ° - 80 ° with respect to the longitudinal axis of the bearing opening (when projecting into a plane of the drawing).

Typical steel materials from which impact tools designed according to the invention are made are martensitically solidifying heat-treatable steels with carbon contents of 0.1-0.70% by weight that are already used for this purpose.

Impact tools according to the invention can also be produced from austenitically solidifying steels with a manganese content of 7-30% by weight. These types of steel, known under the name "Hadfield steels", have also proven themselves in practice for many years in the manufacture of striking tools of the type in question. An example of such a Hadfield steel is the steel commercially available under the standard designation X120Mn12 and material number 1.3401. Hadfield steels show good wear resistance, especially when subjected to impact loads, due to their high work hardening ability.

Furthermore, striking tools according to the invention can be cast from cast iron materials known for this purpose, for example from so-called “white cast iron”, which has a chromium content of up to 29% by weight.

As an alternative to the above-explained casting production of impact tools according to the invention from steel or cast iron materials, it is also possible to produce such impact tools by forging or by flame cutting from a correspondingly shaped preliminary product or as a welded structure from prefabricated parts.

Fig. 1

ein Schlagwerkzeug in perspektivischer Ansicht;

Fig. 2

das Schlagwerkzeug gemäß Fig. 1 in einem Längsschnitt;

Fig. 3 - 6

Ausgestaltungen des Schlagwerkzeugs in einer der Fig. 2 entsprechenden Längsschnitt-Darstellung.

The invention is explained in more detail below with the aid of a drawing showing an exemplary embodiment. They each show schematically and not to scale:

Fig. 1

a striking tool in a perspective view;

Fig. 2

the impact tool according to Fig. 1 in a longitudinal section;

Fig. 3-6

Refinements of the striking tool in one of the Fig. 2 corresponding longitudinal section representation.

The striking tool 1 serves as a hammer when crushing metal scrap, such as vehicle bodies, mineral raw materials or mineral waste, such as building rubble, overburden or the like.

For this purpose, the striking tool is mounted on a conventional rotor, not shown here, in a pendulum manner on an axis of the rotor, also not shown here. This way of oscillating mounting of a striking tool, which belongs to the same type as a striking tool according to the invention, is for example in the EP 1 047 499 B1 described.

In order to fulfill its intended use, the striking tool 1, which is conventionally cast in one piece, for example from Hadfield steel, has a striking section 2 which is hardened by a suitable heat treatment in a manner also known per se, which in practical use comes into contact with the material to be crushed and thereby is exposed to extreme impact loads, and a bearing section 3, which is also thermally treated in a known manner so that it has sufficient toughness and elongation properties through which it is able to absorb the dynamic loads acting on the impact tool 1 during use.

A centrally arranged bearing opening 4 is formed in the bearing section 3 and extends between the end faces 5, 6 of the striking tool 1 over the width B thereof. The central longitudinal axis L of the bearing opening 4 defines the pendulum axis about which the impact tool 1 oscillates around the axis of the rotor, which is usually also made of a steel material. There is metallic frictional contact between the outer circumferential surface of the axis of the rotor and the inner circumferential surface 7 which delimits the bearing opening 4 of the striking tool 1. When new, the shape of the inner circumferential surface 7 corresponds to the shape of a hollow cylinder surface, the diameter of which is equal to the clear width dW of the bearing opening 4.

In the case of the Figures 1 and 2 The shown embodiment of the striking tool 1 are formed in the inner circumferential surface 7 at regular intervals over the width B of the striking tool 1, each formed in the manner of a groove-shaped annular groove and encircling the central longitudinal axis L of the bearing opening 4, depressions 8a-8d. The indentations 8a-8d separate the annular sections of the inner circumferential surface between the indentations 8a-8d.

The depth T measured in the radial direction R and the clear width W measured at the boundary to the inner circumferential surface 7 of the inner circumferential opening surface of the depressions 8a - 8d are dimensioned, taking into account the groove shape of the depressions 8a - 8d, so that on the one hand in the area of the depressions 8a - 8d there is sufficient space for receiving material which, during use, is displaced from the sections of the material of the striking tool 1 which border the bearing opening 4 and which are laterally adjacent to the depressions 8a-8d. On the other hand, the clear width W of the depressions 8a - 8d is dimensioned such that the inner circumferential openings of the depressions 8a - 8d, for example, take up about 40% of the total inner circumferential surface 7, i.e. the inner circumferential surface of a hollow cylinder, the diameter of which corresponds to the clear width dW of the bearing opening 4.

At the in Fig. 3 In the embodiment shown, there are also a plurality of groove-shaped depressions 8e-8g distributed at regular intervals around the circumference of the bearing opening 4, which in the case of the FIG Fig. 2 The projection made into the plane of the drawing in relation to the central longitudinal axis L of the bearing opening is aligned at an angle of 45 ° and extends in a spiral-like manner in the longitudinal LR and circumferential direction UR of the bearing opening 4.

At the in Fig. 4 In the embodiment shown, the inner circumferential surface 7 is also profiled by groove-like depressions 8h-8l, which in the projection into the plane of the drawing have isosceles converging in a V-shape and angled by 45 ° with respect to the longitudinal axis L.

In the Figures 5 and 6 In the variants shown, the depressions 8m and 8n form a coherent pattern-like structure in which the diamond-shaped ( Fig. 5 ) or circular ( Fig. 6 ) Shaped circumferential surface sections 9a - 9c; 10a - 10c are delimited on all sides in the longitudinal and circumferential directions by the respective indentation 8m, 8n, so that adjacent circumferential surface sections 9a - 9c; 10a - 10c are separated from one another by a section of the respective indentation 8m, 8n are. Such a structuring of the inner circumferential surface 7 by the depressions 8m, 8n has the advantage that material expansions in the circumferential and longitudinal direction of the bearing opening 4 can be safely absorbed by the depressions 8m, 8n.

REFERENCE MARK

1

Impact tool

2

Flapping section

3

Warehouse section

4th

Warehouse opening

5.6

Front faces of the striking tool 1

7th

Inner peripheral surface of the bearing hole 4

8a - 8n

Depressions in the inner circumferential surface 7

9a-9c

Circumferential surface sections

10a-10c

Circumferential surface sections

B.

Impact tool width 1

dW

clear width dW of the bearing opening 4

L.

central longitudinal axis of the bearing opening 4

LR

Longitudinal direction

R.

radial direction

T

Depth of the depressions 8a-8n

UR

Circumferential direction

W.

clear width of the inner circumferential opening area of the depressions 8a-8n

Claims (12)

1. Striking tool for crushing metal objects or stone materials, manufactured from an iron-based material and comprising a bearing section (3), into which a bearing opening (4) provided for the freely swinging mounting of the striking tool (1) on a metallic shaft formed with an inner circumferential surface (7) surrounding the bearing opening (4), wherein during use there is metallic frictional contact between the outer circumferential surface of the shaft and the inner circumferential surface (7) of the bearing opening (4) of the striking tool (1), and comprising a striking section (2), which during use is exposed to a striking load by contact with the material to be crushed, characterized in that at least one recess (8a to 8n) is formed into a section of the inner circumferential surface (7) of the bearing opening (4), which is provided to receive metallic material of the striking tool (1) laterally adjoining the recess (8a to 8n) and displaced during use, wherein the recess (8e to 8g) circulates in a spiral manner around the bearing.opening (4) and/or wherein the recess (8m, 8n) completely surrounds at least one circumferential surface region (9a, 9b; 10a, 10b) of the inner circumferential surface (7) in the longitudinal (LR) and circumferential direction (UR) of the inner circumferential surface (7) and/or wherein two or more recesses (8a to 8k) are formed into the inner circumferential surface (7) of the bearing eye distributed in the longitudinal direction (LR) of the bearing opening (4).
2. Striking tool according to claim 1, characterised in that the recess (8a to 8n) is provided at least in one section of the inner circumferential surface (7) of the bearing opening (4), which is loaded with pressure during use.
3. Striking tool according to any one of the preceding claims, characterised in that in the section of the inner circumferential surface (7) of the bearing opening (4) provided with the recess (8a to 8n) a surface structure is formed through the recess (8a to 8n) in which at least one circumferential surface region of the inner circumferential surface (7) is separated by the recess from an adjacent circumferential surface region of the inner circumferential surface (7).
4. Striking tool according to any one of the preceding claims, characterised in that the recess (8a to 8g) circulates around the bearing opening (4).
5. Striking tool according to any one of the preceding claims, characterised in that the recess (8a to 8k) is formed in the manner of a channel.
6. Striking tool according to claim 4 and 5, characterized in that the recess (8a to 8d) circulates around the bearing opening (4) in the manner of a ring groove.
7. Striking tool according to any one of the preceding claims, characterized in that the circumferential surface region (9a, 9b; 10a, 10b) surrounded by the recess (8n, 8m) is elliptical, circular, square or rhombus-shaped.
8. Striking tool according to any one of the preceding claims, characterized in that the depth (T) of the recess (8a to 8n) measured in the radial direction (R) proceeding from the inner circumferential surface (7) into the material of the striking tool (1) is at least the same thickness of a surface layer adjoining the inner circumferential surface (7), whose hardness is less than the hardness of a core layer of the striking tool (1) adjoining the surface layer and delimited by the surface layer with respect to the bearing opening (4).
9. Striking tool according to claim 8, characterized in that the depth (T) of the recess is 2 to 30 mm.
10. Striking tool according to any one of the preceding claims, characterized in that the recess occupies 25 to 50% of the inner circumferential surface (7) of the bearing opening (4).
11. Striking tool according to any one of the preceding claims, characterized in that it consists of an iron or steel cast material.
12. Rotor for a machine for crushing metal objects or stone materials, comprising at least one metallic shaft, on which the at least one striking tool (1) formed according to any one of the preceding claims is mounted with its bearing opening (4), wherein there is metallic frictional contact between the outer circumferential surface of the shaft and the inner circumferential surface (7) of the bearing opening (4) of the striking tool (1).

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