EP1907122B1

EP1907122B1 - Rubble grinder

Info

Publication number: EP1907122B1
Application number: EP05778746A
Authority: EP
Inventors: Bruno Venturi; Marco Venturi; Franco Ferraresi
Original assignee: Cams SRL
Current assignee: Cams SRL
Priority date: 2005-07-19
Filing date: 2005-07-19
Publication date: 2009-09-09
Anticipated expiration: 2025-07-19
Also published as: EP1907122A1; ATE442203T1; DE602005016614D1; WO2007010563A1

Abstract

A grinder (10) for rubble comprising: a container space (1) which accommodates the material to be crushed; two rotors (3, 4) positioned inside the container space (1), which convey the material to be processed to a crushing area and which present a plurality of discs (5, 105) distributed along their length, each of the discs (5, 105) presenting on the edge (6, 106) a plurality of teeth (7, 107) suitable to crush the material. Each tooth (7, 107) presents: a first part (71, 171), which comes into contact with the material to be crushed; a second part (72, 172) attached to the edge (6, 106) of the discs (7, 107) by joining means (11, 111) and presenting a first hole (721) with an axis substantially perpendicular to the midplane of the tooth (7, 107), this first hole (721) being suitable to accommodate a fixing pin (8, 108) passing through a corresponding second hole (62, 162) present near the edge (6, 106) of the disc (5, 105).

Description

This invention concerns a rubble grinder mainly suitable for grinding particularly resistant materials.
More specifically, the invention concerns the special shape of each of the grinder tools which process the rubble.
From here on the term tool or tooth shall have the same meaning.
There are various types of grinders used to break up both urban and industrial waste into pieces (see US 4 946 109 disclosing a grinder according to preamble of claim 1. The sector for which this invention is especially, but not exclusively, intended is
the sector for grinding rubble such as, for example, the rubble originating from the demolition of buildings or from their destruction due to natural disasters.
Rubble of this type is generally the mixed type such as, for example, blocks of reinforced concrete and concrete in which steel rods are embedded.
The resistance to impact for breaking up this rubble obviously differs according to the tool used to strike the concrete or the steel rod.
It is however evident that the tools used to break up the materials are subjected to a very high degree of wear even if special high-resistance steel is used.
It is therefore necessary to periodically carry out maintenance operations on the grinder, replacing the worn tools with new ones.
A type of grinder for soft material waste is known in which the grinder has two parallel substantially cylindrical rotors turning in opposite directions.
The rotors are connected to crushing tools which are positioned around the circumference at regular intervals and housed in supports directly welded on the rotor.
The tools are interchangeable, being fixed to the support by means of a screw and locking nut. The screw and nut clamp the tool to the support.
This type of solution is suitable for processing and crushing soft material, but cannot be used for the rubble initially described since the nut which clamps the tool together with the screw would very quickly become worn.
As a result of this wear, replacement of the tool would indeed become impracticable since it would be impossible to remove the nut from the screw.
The known machines for processing rubble, which is very hard material, generally consist of hammer mills or grinders comprising a pair of counterrotating rotors equipped with tools arranged radially and positioned along circumferences equidistant from the rotating cylinders.
The grinder tools are welded to the rotors so that their replacement, due to the wear to which they are subjected, involves the removal of the welding to free the tooth followed by new welding to fit the new tooth.
It is obvious that this system not only involves a long and costly operation but also damages the physical structure of the rotor since the areas in which the welding is carried out are subjected to thermal shocks which weaken the material to an unacceptable extent for the considerable strain to which the rotor is subjected.
The aim of this invention is to overcome the limitations of the prior art described above.
The main aim of the invention is to produce a rubble grinder equipped with tools that are easily interchangeable without having to remove and redo the welding.
A further aim is to equip the grinder with tools that are able to withstand the heaviest stress due, for example, to the presence of steel rods embedded in the concrete.
Another aim of the invention is to facilitate the tool fitting and removal operations so that worn tools can be easily replaced also by not particularly expert personnel.
An additional aim of the invention is to facilitate the tool fitting and removal operations so that differently shaped tools for the various types of material to be processed can be fitted easily.
All the aims described above together with others which will be described in greater detail below are achieved by the grinder according to the invention as defined in the claims.
According to the invention, the joining means comprise a shank, protruding from the second part of the tooth, which is inserted in a slot made in the edge of the disc.
In this embodiment, the second part of the tooth presents a curved recess in its lower edge, positioned in correspondence with a through hole made near the edge of the disc.
The through hole and the recess can thus accommodate another fixing pin. Advantageously, this additional fixing pin provides excellent stability of the tooth with respect to the edge of the disc to which it is connected.
According to a variation, the joining means comprise a shank, protruding from the edge of the disc, which is inserted in a slot made in the second part of the tooth.
The tooth has a truncated cone cross-section so that it can be inserted as a wedge in a respective housing present in the edge of the disc.
Advantageously, this variation, which is an alternative to the previously described embodiment, also ensures excellent stability of the tooth with respect to the edge of the disc to which it is connected, replacing the use of the additional fixing pin with the wedge joint.
Also advantageously, the pins present in the above-mentioned embodiments, being arranged transversally with respect to the midplane of each tooth, are protected against the blows made by the material on the tooth during processing operations both when the rotor rotates in the working direction and when it rotates in the opposite direction to unblock the jamming of the machine when it encounters material that cannot be crushed.
It is indeed in this latter situation that the tooth on each disc would tend to become detached from its housing if it were not sufficiently anchored in place and prevented from making this movement, as on the other hand is ensured by this invention.
Additional features and details of the invention will be more evident on reading the description of a preferred embodiment of the invention, given as a non-binding example and illustrated in the accompanying drawings in which:

fig. 1 shows a cross-section of the grinder according to the invention;
figs. 2 to 4 show some details of the grinder according to the invention;
figs. 5 to 7 show some details of an embodiment of the grinder according to the invention.

With reference to fig. 1 it can be seen that the rubble grinder according to the invention, indicated in general with the reference number 10, presents a container space 1, suitable to accommodate the material to be crushed, equipped with two rotor 3 and 4, arranged paraller to each other, each being driven by a motor, respectively 31 and 41.
The rotors 3 and 4 turn in opposite directions in order to convey the material to be processed into the space between them which forms the crushing area.
According to another embodiment of the invention, the distance between the axes of the rotors can be adjustable through means of the known type in order to obtain different sizes of the pieces of crushed material according to requirements.
According to a further embodiment of the invention, not described and not shown in the drawings, there is only one rotor and the crushing area is located in the space between the rotor and one counter wall.
Each rotor 3 and 4 presents a series of discs 5, an example of which can be seen in fig. 2, which are spaced out at regular intervals along the length of each rotor 3, 4.
These are rigidly connected to the rotor by means, for example, of an opening 51 which, in the case of the example in fig. 2, is substantially square and which is coupled to the square cross-section rotor shaft.
This embodiment should be intended as not being restrictive as regards other different embodiments according to which the discs are connected to the rotor in different ways, such as, for example, by means of protrusions present on the surface of the discs and which are accommodated in appropriate housings inside the rotor.
According to the preferred embodiment described here, the disc 5 presents a vaguely triangular shape formed by three curves which define three zones positioned at 120° to each other, each being connected to a tooth 7.
According to the invention, each tooth 7 presents a first part 71, which comes into contact with the material to be crushed, and a second part 72 connected to the edge 6 of the discs 5 by joining means 11.
As can be seen in fig. 3, the first part 71 of the tooth 7 presents an upper portion 75 which protrudes with respect to the rest of the body 76.
This upper portion 75 is the actual working area of the tooth 7 and also represents the part subject to wear.
It is followed by a downwardly decreasing pyramidal profile.
As regards the second part 72, this presents at least a first hole 721 the axis of which is perpendicular to the midplane of the tooth 7.
When the tooth is attached to the edge 6 of the disc 5, this first hole 721 accommodates a through fixing pin 8, as can be seen in fig. 4, for a second hole 62 present near the edge of the disc 5.
The fixing pin 8 is therefore at right angles to the midplane of the tooth 7.
According to the preferred embodiment described here and shown in fig. 3 , the joining means 11 comprise a shank 73, present on the second part 72 of the tooth 7, which is inserted in a slot 61 present in the edge 6 of the disc 5.
The thickness s of the shank 73 is less than the thickness S of the first part 71.
In addition to the first hole 721, the shank 73 also presents an arch-shaped recess 722 on the lower edge 723 of the shank 73.
As can be seen in fig. 4, when the tooth 7 is attached to the edge 6 of the disc 5, the recess 722 is positioned in correspondence with a through hole 63, present near the edge 6 of the disc 5, and together with this through hole 63 accommodates another fixing pin 9.
This additional pin 9 is also at right angles to the midplane of the tooth 7.
In this way, the fixing pins 8 and 9, respectively inserted in the holes 62 and 63 near the edge 6 of the disc 5, in the hole 721 and in the recess 722 firmly clamp the tooth 7 to the disc 5.
It should be noted that the substantially parallelepiped shape of the shank 73 prevents the tooth 7 from slipping out of the slot 61 in the disc 5 even if it is subjected to recoil due to rejection of the material or to the inverted rotation of the rotor activated to unblock the material jamming the rotation of the rotors 3, 4.
It should also be pointed out that the position of the two pins perpendicular to the midplane of the tooth prevents them from being damaged in any way so that, when it is necessary to replace the tooth due to normal wear and tear, a few hammer blows together with the help of a nail are sufficient to remove the pins and free the tooth from its housing.
As regards the lower edge 723 of the tooth 7, this also comprises an overhang 731 suitable to be inserted in the slot 61.
This overhang 731 helps the positioning of the tooth 7 holding it in place during the lateral stress to which the tooth 7 is subjected.
According to a different embodiment, which can be seen in fig. 5, the joining means 111 comprise a shank 161, protruding from the edge 106 of the disc 105, which is inserted in a slot 173 present in the second part 172 of the tooth 107.
In particular, as can be seen in fig. 6, the housing 112 of the tooth 107, cut in the edge 106 of the disc 105, presents a truncated cone profile matching that of the tooth 107 so that the tooth 107 is inserted like a wedge in the housing 112.
This ensures the fixing stability of the tooth to the disc with an alternative embodiment to the presence of the last pin present in the embodiment described previously.
With regard to the first part 171 of the tooth 107, as can be seen in fig. 7, this embodiment also presents an upper portion 175 which protrudes with respect to the rest of the body 176.
This upper portion 175 is the actual working area of the tooth 107 and is also the part which becomes worn.
As has been shown, all the aims of the invention have been achieved.
In particular, the aims of achieving a simple and inexpensive coupling between the housing and the tooth and also an equally simple removal of the worn tooth without additional problems have been achieved.
Furthermore, the shape of the tooth is such that any movement tending to shift the tooth from its housing during working operations is in fact prevented.
During construction, modifications or additional variations may be made to the grinder according to the invention, which, although not described or shown here, can be considered as protected by this patent on condition they are within the scope of the claims which follow.

Claims

A grinder (10) for rubble comprising:
- a container space (1) to accommodate the material to be crushed and internally equipped with

- at least one rotor (3, 4) which conveys the material to be processed to a crushing area and which presents a plurality of discs (5) distributed along the length of said rotor (3, 4), the edge (6) of each of said discs (5) presenting a plurality of teeth (7) suitable to crush the material, each of said teeth (7) presenting:
- a first part (71) which comes into contact with the material to be crushed and

- a second part (72) presenting at least one first hole (721) the axis of which is substantially perpendicular to the midplane of said tooth (7) and suitable to accommodate one fixing pin (8) passing through a corresponding second hole (62) present near said edge (6) of said disc (5),
characterised in that, in correspondence with the lower edge (723) of said second part (72) of said tooth (7), at least an arch-shaped recess (722) is positioned in correspondence with a through hole (63) made near said edge (6) of said disc (5) and suitable to accommodate an additional fixing pin (9) passing through said hole (63) made near said edge (6) of said disc (5), and in that
said second part (72) of said tooth cooperating with said edge (6) of said disc (5) through joining means (11) comprises:
- a shank (73), protruding from said tooth (7) and suitable to be inserted in a slot (61) cut in at least one portion of said edge (6) of said disc (5) and

- an overhang (731) on the lower edge (723) of said second part (72) of said tooth (7) and suitable to be inserted in said slot (61) of said edge (6) of said disc (5).
The grinder (10) according to claim 1) characterised in that it presents at least two rotors (3, 4) arranged parallel to each other and turning in opposite directions in order to convey the material to be processed into the space between said two rotors (3, 4), said space forming said crushing area.
The grinder (10) according to claim 1) characterised in that said midplane of said tooth (7) is parallel to the midplane of said disc (5).
The grinder (10) according to any of the preceding claims characterised in that said first part (71) of said tooth (7) presents an upper portion (75) which protrudes with respect to the rest of the body (76) followed by a downwardly decreasing pyramidal profile.
The grinder (10) according to any of the preceding claims characterised in that each of said discs (5) houses three teeth (7) positioned at 120° to each other.