FR2785203A1 - KNIFE FOR SHREDDERS WITH ROTARY SHEARS SUITABLE TO BE THREADED ON A SHAFT WITH CROSS-SECTION OF REGULAR POLYGONAL SHAPE AND SHREDDER WITH SUCH A KNIFE - Google Patents

Abstract

The present invention relates to knives for rotary shredder shredders and to shredders made with these knives. The knife 100 according to the invention is essentially characterized by the fact that it comprises a cylindrical disc of revolution 1, a central opening 2 made in the disc and having a regular polygonal shape with x sides 4, and y teeth 5, 6, 7 located at the periphery 8 of the disc 1, these teeth being located respectively on y radial straight lines 15, 16, 17, two of them consecutive making an angle A equal to (CF DRAWING IN BOPI) the others making angles between them B equal to (CF DRAWING IN BOPI) The crusher 200 applying the knife 100 defined above comprises at least one rotation shaft 20 with a regular polygonal section with x sides complementary to the shape of the opening 2, a plurality of knives 100 threaded onto the rotation shaft 20, and a plurality of spacers 21, each spacer being interposed between two consecutive knives 100, two consecutive knives 100 being angularly offset with respect to each other by (CF DRAWING IN BOPI)

Description

The present invention relates to knives entering into the constitution

  rotary shredder shredders, i.e. devices which make it possible to reduce the volume of numerous objects and bodies of all kinds by shredding them with a view for example to their storage and / or possibly their transport to places treatment, recycling and / or disposal. Shredders are known, such as for example those described in EP-A-0 667 187 and EP-A-0 760 257, which comprise at least one rotation shaft fixed in a box, with a cross section of regular polygonal shape, and a plurality of knives threaded on this rotation shaft in

  being separated from each other by spacers.

  A knife for such a grinder generally consists of a cylindrical disc of revolution, of a central breakthrough of regular polygonal shape made in the disc and complementary to the cross section.

  of the rotation shaft, and of teeth distributed around the periphery of the disc.

  It is also known that, for a grinder to give good results, it is in particular necessary to subject the bodies and / or objects to be ground to torsional tearing forces or the like, just before their grinding and / or shredding . For this purpose, the teeth should not be all

  arranged on the same straight line parallel to the axis of the rotation shaft.

  In most current mills, the cross section of the rotation shafts, as well as, in a complementary manner, the central breakthrough of the knives, have a regular hexagonal shape. In addition, to allow the shredders to operate at an acceptable yield for all kinds of objects, the knives often have three teeth regularly distributed at

  the periphery of the disc, 120 from one another.

  It is therefore necessary to provide different types of knife made so that, for each type of knife, the teeth are angularly offset relative to the position of these teeth for the other types of knife, relative to the breakthrough made in the center of the disc, so that, when these knives are threaded on the rotation shaft, the teeth are not aligned along a straight line parallel to the axis of this rotation shaft, but

  angularly offset from each other.

  By way of example, with knives with a hexagonal central breakthrough and comprising three teeth regularly distributed around the periphery of the disc, there are generally provided four types of knife, in which the position of the three teeth is angularly offset from the position of the central breakthrough,

  0, 15, 30 and 45 respectively.

  Consequently, shredder manufacturers must stockpile these four different types of knife, which influences the cost price of these shredders because, not only is it first necessary to produce four different types of knife, but it is also necessary to manage stocks very seriously to be able to meet customer demand and / or its

own manufacture.

  Also, the present invention aims to achieve a knife

  for a shredder which does not have the drawback described above.

  More specifically, the subject of the present invention is a knife for a grinder, comprising a cylindrical disk of revolution, a central breakthrough made in the disc, said central breakout being of regular polygonal shape with x sides, and v teeth located at the periphery of the disc. , y being at least equal to two, characterized in that the y teeth are situated on the periphery of the disc respectively on y radial straight lines, two of them consecutive making an angle A equal to 360. Y +, the others making xy between them angles B equal to 360. xy - y -1 (y -1) xy According to another characteristic of the invention, x is equal to six and v. at three. The present invention also relates to a grinder applying the knife defined above, characterized in that it comprises at least one rotation shaft with regular polygonal cross section with x sides complementary to the shape of said central breakthrough, a plurality of knives threaded on the rotation shaft, and a plurality of spacers, each spacer being interposed between two consecutive knives, two consecutive knives being angularly offset relative to each other by 360 X Other characteristics and advantages of the present invention

  will appear during the following description given with reference to the drawings

  annexed by way of illustration, but in no way limiting, in which: FIG. 1 represents a block diagram of an embodiment of a knife for a grinder according to the invention, comprising three teeth and a central breakthrough of regular hexagonal shape, La 2 shows a diagram for explaining the result obtained when a crusher is equipped with six knives like that schematically shown in Figure 1, Figure 3 shows an advantageous embodiment of a knife according to the invention, according to block diagram according to FIG. 1, and FIG. 4 represents, in top view, an embodiment of a part of a crusher equipped with six knives like those represented on the

Figures 1 or 3.

  The Applicant wishes to specify that the figures represent only examples of the embodiment of the object according to the invention, but that there may be

  other embodiments that meet the definition of this invention.

  It also specifies that, when, according to the definition of the invention, the object of the invention comprises "at least one" element having a function

  given, the embodiment described may include several of these elements.

  It also specifies that, if the embodiment of the object according to the invention as illustrated comprises several elements of identical function and if, in the

  description, it is not specified that the object according to this invention must

  necessarily include a particular number of these elements, the object of the invention may be defined as comprising "at least one" of these elements. It is finally specified that, for the simplification of the present

  description, the same means have the same references whatever the

  figure on which they appear and whatever the shape of the

representation of these means.

  This having been clarified, FIG. 1 schematically represents a first embodiment of a knife 100 according to the invention. This knife has a cylindrical disc of revolution 1, a central breakthrough 2 made in the disc, that is to say so that its axis 3 is coincident with that of

  disk. The section of this breakthrough is of regular polygonal shape with x sides 4.

  In the example illustrated, this shape is a regular hexagon and the number x is therefore equal to six but it is specified that, in the context of this

  description, "regular polygonal shape" means any shape

  regular polygonal in the mathematical sense, and also any shape which makes it possible to obtain the same result, that is to say which makes it possible to define a number of regular angular positions, for example grooved shapes or the like. The knife 100 further comprises y teeth 5, 6, 7 located at the periphery 8 of the disc 1, being there at least equal to two. In the preferred example illustrated,

  this number of teeth is equal to three.

  According to an important characteristic of the present invention, the y teeth 5, 6, 7 are located at the periphery of the disc respectively on y radial lines 15, 16, 17, two of them consecutive 15 and 16 forming an angle A equal to 360. y +1, the others, 15 and 17 on the one hand, 16 and 17 on the other, making xy between them angles B equal to 360. xy - y -1 (y -1) xy In the case of the illustrated example, in which the central opening 2 is of regular hexagonal shape and y is equal to three, the angle A is equal to 80 and the

  two other angles B are both equal to 140, FIGS. 1 and 3.

  However, it is possible to produce other forms of knife according to the invention. In particular, x can be equal to eight and y to three. In this case, the angle

  A is equal to 60 and the two angles B are equal to 150.

  For x equal to six and v to two, the angle A would be equal to 90 and the value of the single angle B would be equal to 270c. For x equal to eight and v to two, the angle A would be equal

  to 67.5 and the value of the single angle B is 292.5, and so on.

  Note that in the formulas defined above, x must be at least three. Furthermore, it was found by the inventor that the most suitable tooth distributions were obtained when x is a number

even, for example equal to six.

  It is however quite obvious that the person skilled in the art will be able to choose the solution which will best suit the problem of the crusher which he will have to build and / or use. The examples given above already provide solutions which have made it possible to obtain very good results. These solutions actually address most of the problems that can arise.

present to a skilled person.

  FIG. 3 represents another embodiment of a knife according to the invention, in which the teeth 5-7 have a particular shape which allows them to be more resistant to forces and therefore to more easily absorb them. This embodiment is adopted in particular when it is necessary to tear and grind very solid and hard objects or bodies. These teeth have the particularity of having a steep front flank 10 substantially coincident with the radial straight lines 15, 16, 17 defined above, to form a "hook" or the like, and a rear flange 11 advantageously curved connecting in gentle slope the top of the front flank 10 and the periphery 8 of the disc 1,

  substantially at the base of the front flank of the next tooth.

  The two figures 1 and 3 represent two possible forms of teeth for a knife according to the invention, but it is obvious that there may be other

  tooth shapes, for example trapezoidal shapes.

  Figure 4 shows part of a crusher 200 applying

knife according to the invention.

  This crusher comprises at least one rotation shaft 20 of regular polygonal cross section with x sides complementary to the shape of the central opening 2, a plurality of knives 100 threaded on the rotation shaft 20, and a plurality of spacers 21, each spacer being interposed between two consecutive knives, two consecutive knives 100 360 being offset angularly with respect to each other by 360 In the advantageous example illustrated, the cross section of the rotation shaft 20 has a hexagonal regular and the number of knives 100 threaded on the shaft 20 is equal to six, these six knives 100 being regularly angularly offset from one another by 60. But it is obvious that the number of knives threaded on the rotation shaft can be different from six,

especially greater than six.

  FIG. 2 represents, in projection in a plane perpendicular to the axis 3, in the case ox is equal to six and y to three, all the possible positions of the teeth when the knife is regularly angularly offset by 60, that is to say that is to say when he successively takes the six possible positions by

relative to the rotation shaft 20.

  In the first position of the knife 100 relative to the shaft 20, the

  three teeth 5-7 are respectively in the positions referenced 51, 61 and 71.

  When the knife is angularly offset by 60, the three teeth take the respective positions referenced 511, 611 and 711, and so on until the sixth angular offset of the knife, by 300 'from its initial position, where the

  teeth are in the positions respectively referenced 5V ,, 6VI and 7VI.

  The different positions of the teeth referenced in FIG. 2 are shown in FIG. 4 which perfectly demonstrates that, with a single structural configuration of the knife, but by shifting each knife, by 360 relative to the previous one, by an angular value equal to 3, it is possible to obtain a grinder configuration in which teeth 5-7 are all

  perfectly offset from each other.

  The structure of knife for shredder described above eliminates the drawbacks mentioned above of knives according to the prior art, because it is undeniable that this structure allows to use only one type of knife for the realization shredders just as efficient as the shredders obtained with the previous knives, but of a

  significantly lower cost price.

Claims (4)

  1- Knife (100) for grinder (200), comprising a cylindrical disk of revolution (1), a central breakthrough (2) produced in the disc, said central breakthrough having a regular polygonal shape with x sides (4), and v teeth (5, 6, 7) located at the periphery (8) of the disc (1), being there at least equal to two, characterized in that the v teeth (5, 6, 7) are located at the periphery of the disc respectively on y radial lines (15, 16, 17), two of them consecutive making an angle A equal to 360. Y +4 ,, the others making angles B equal to 360 between Xy. xy - y -1 (y -1) xy '2- Knife according to claim 1, characterized in that x is a even number.   3- knife (100) according to claim 2, characterized in that   said breakthrough (2) is of regular hexagonal shape.   4- knife (100) according to claim 3, characterized in that y is equal to three, the angle A then being equal to 80, the other two angles B being equal to 140.   - Crusher (200) applying the knife (100) according to claim 1, characterized in that it comprises at least one rotation shaft (20) with a cross section of regular polygonal shape with x sides complementary to the shape of said breakthrough (2), a plurality of knives (100) threaded on the rotation shaft (20), and a plurality of spacers (21), each spacer being interposed between two consecutive knives (100), two consecutive knives (100 ) being angularly offset one with respect to the other from 360.   x 6- Mill according to claim 5, characterized in that x is a even number.   7- crusher according to claim 6, characterized in that the cross section of said rotation shaft (20) is of regular hexagonal shape, that the number of knives (100) threaded on said shaft (20) is at least equal to six , these six knives (100) being regularly angularly offset one compared to others of 60.