Bottom grate of a crusher or drum chipper and method of producing the bottom grate

Abstract

A bottom grate for a crusher for chipping or comminuting material which includes: support ribs each substantially perpendicular to the rotational axis of the crusher; grate blades mounted to the support ribs and substantially parallel to the rotational axis, wherein the grate blades are releasably mounted to the support ribs and the grate blades each have a cutting edge proximate to a cutting or crushing rotor in the crusher; pulling members extending between two of the support members, wherein the pulling members are in tension and the tension in the pulling members binds the blades in the support members.

Claims

1. A curved bottom grate configured for a crusher for chipping or comminuting material, wherein the curved bottom grate comprises: curved end support elements and curved intermediate support elements each configured to be perpendicular to a rotational axis of a rotor of the crusher; grate blades configured to be parallel to the rotational axis of the rotor and supported by at least the curved intermediate support elements, and disengageable pulling members configured to be parallel to the rotational axis and each of the pulling members attached to and extending between the curved end support elements, and extending across the curved intermediate support elements, wherein the pulling members are under tension and apply a compressive force to the curved end support members which clamp the grate blades between the curved end support members.

2. The bottom grate according to claim 1, whereby the grate blades slidably engage the curved intermediate support elements.

3. The bottom grate according to claim 1, wherein the grate blade is longitudinally divided into blade pieces and each of the blade pieces is between adjacent ones of the intermediate and end support members.

4. The bottom grate according to claim 1 wherein the grate blades each have a cutting edge on opposite sides of the blade and each of the grate blades is reversible within the bottom grate.

5. The bottom grate according to claim 1, wherein the curved intermediate support elements each include guide grooves and each of the guide grooves receives a respective one of the grate blades.

6. The bottom grate according to claim 1 wherein the pulling members each include a threaded rod extending through the curved end support elements and through the curved intermediate support elements.

7. The bottom grate according to claim 1, wherein the pulling members are proximate and parallel to the grate blades.

8. The curved bottom grate of claim 1 wherein the curved end support elements and the curved intermediate support elements are plates having a bow shape.

9. The bottom grate of claim 1 wherein the pulling members are rods having threaded ends, the threaded ends extend through holes in the curved end support elements and nuts engage the threaded ends to apply the tension to the pulling members.

10. A crusher for chipping or comminuting material comprising: a stationary body; a cylindrical rotor mounted rotatably to the stationary body, the cylindrical rotor including an outer circumference surface and a rotational axis; rotor blades aligned with the outer circumferential surface of the cylindrical rotor, and a stationary curved bottom grate coupled to the stationary body and positioned below the cylindrical rotor, curved bottom grate includes: curved end support elements and curved intermediate element support elements, wherein each of the curved end support elements and the curved intermediate support elements are perpendicular to the rotational axis, wherein the curved intermediate support elements are between the curved end support elements; grate blades parallel to the rotational axis, wherein the grate blades are each releasably mounted to the curved intermediate support elements and the grate blades each have a cutting edge proximate to the outer circumferential surface of the cylindrical rotor; pulling members extending between the curved end support members and having opposite ends each coupled to one of the curved end support members, wherein the pulling members are each in tension and apply a compressive force to the curved end support members, wherein the compressive force applied to the curved end support members clamp the grate blades between the curved end support members.

11. The crusher according to claim 10 wherein the grate blades slidably engage the curved intermediate support elements.

12. The crusher according to claim 10 wherein the grate blades are each longitudinally divided into blade pieces.

13. The crusher according to claim 10 the grate blades each have cutting edges at opposite sides of the grate blade.

14. The crusher according to claim 10, wherein the curved intermediate support elements each include guide grooves wherein each guide groove receives a respective one of the grate blades and aligns the respective one of the grate blades with the curved intermediate support element.

15. The crusher according to claim 10 further comprising slots or holes in each of the curved intermediate support elements, wherein the grate blades are received in the slots or holes.

16. The crusher according to claim 10 wherein the pulling members each include at least one threaded rod extending through the curved end support elements and the curved intermediate support elements.

17. The crusher according to claim 10 wherein the pulling members each position one of the grate blades in the bottom grate.

18. A bottom grate for a crusher for chipping or comminuting material comprising: curved end support elements and curved intermediate support elements, wherein the curved end support elements and the curved intermediate support elements are each configured to be perpendicular to a rotational axis of a rotor of the crusher; grate blades slidably mounted to the curved intermediate support elements and configured to be parallel to the rotational axis, wherein the grate blades are releasably mounted to the intermediate support elements and the grate blades each have a cutting edge, and pulling members extending through the curved intermediate support elements and releasably attached to the end curved support elements, wherein the pulling members are in tension and apply a clamping force to the end curved support elements which clamps the grate blades between the curved end support elements.

19. The bottom grate of claim 18 wherein the curved end support elements and the curved intermediate support elements are plates having a bow shape.

20. The bottom grate of claim 18 wherein the pulling members are rods having threaded ends, the threaded ends extend through holes in the curved end support elements and nuts engage the threaded ends to apply the tension to the pulling members.

21. The bottom grate of claim 18, wherein the grate blade is longitudinally divided into blade pieces and each of the blade pieces is between adjacent ones of the intermediate and end support members.

Description

LIST OF DRAWINGS

(1) In the following, the invention is disclosed in more detail with reference to the appended drawings, where:

(2) FIG. 1 illustrates a perspective general view of a crusher, also showing means for transferring the bottom grate into the crusher and out of there,

(3) FIG. 2 illustrates an end view of a crusher provided with a bottom grate according to the invention in the longitudinal direction of the rotor, and

(4) FIG. 3a illustrates a perspective view of a bottom grate for a crusher or drum chipper according to the invention, and

(5) FIG. 3b illustrates in close view a detail of the bottom grate of FIG. 3a relating to the fitting of the blades between the support elements in zone A.

(6) FIG. 3c illustrates in close view a detail of the bottom grate of FIG. 3a relating to the fitting of the blades between the support elements in zone B.

DETAILED DESCRIPTION OF THE INVENTION

(7) FIGS. 1 and 2 illustrates a crusher 1 for chipping and/or comminuting material. The crusher 1 has a stationary body 3 provided with counter blades (not shown) and their position and distance are adapted in relation to a rotor 5 mounted rotatably on bearings inside the body. Crushing or cutting blades 55 are arranged on the outer circumference of the rotor 5.

(8) A bottom grate 7 in accordance with the invention is mounted below the rotor 5. The bottom grate 7 is curved following the shape of the rotor 5. There are end support elements 11 and intermediate support elements 13 in a direction perpendicular to rotor 5 axis supporting the blades 9 substantially parallel to the rotor axis. Openings 91 are formed between them for exiting the treated material.

(9) FIGS. 2, 3a, 3b and 3c illustrates in more detail a bottom grate 7 for a crusher according to the invention and the fitting of the grate. Thus, main components thereof comprise end support elements 11 and intermediate support elements 13 extending curvedly substantially perpendicular to the axis of the rotor 5 and conforming to the outer circumference of the rotor, blades 9 substantially parallel to the axis of the rotor 5, and pulling members such as threaded rods 17 also extending substantially in the direction of the rotor axis.

(10) The form locking joints and axially directed pulling force makes longitudinal division of the blades 9 to shorter blade pieces 9 possible. The minimum length of an individual blade piece is a distance from one support element to a closest support element plus dimensions needed for the form-locking joints. The individual blade piece may also be assembled between two support elements which are not closest to each other whereby the length of the blade piece will then be a multiple of distances between support elements.

(11) A subframe 14 may be installed to one or both sides of the bottom grate to keep the support elements 11, 13 in their right places and make the structure more rigid and to bear at least part of the workloads. It may also be used to attach the bottom grate 7 to the crusher 1 or other elements of it. When joints between subframe and support elements 11, 13 can be disengaged e.g by using bolts, blades 9 or blade pieces 9 can more easily be replaced individually.

(12) The outermost curved end support elements 11, may differ from the intermediate curved support elements 13. They may be formed stronger than the intermediate support elements 13 and are provided with means for receiving and fastening the pulling members 17. The end support elements 11 direct pressing force to the joint between end support elements 11 and the blades 9 or blade pieces 9. A slot or other form-locking or supporting and guiding means 131 may be arranged in the end support elements 11 to keep the blades 9 or blade pieces 9 in their intended position. Then the friction is not the only factor which keeps the ends of the blades or blade pieces 9 in their correct position. The blades 9 or blade pieces 9 may also have corresponding slots or brackets to fit with form-locking means to support elements 11, 13.

(13) To avoid buckling under compressive force and twisting induced by cutting forces, the intermediate support elements 13 may also offer lateral support to keep the blades 9 or blade pieces 9 in their straight shape and position. Intermediate support elements 13 may also be involved in the crushing or cutting operation. All shapes of the intermediate support elements 13 do not need to be equal. If, for example every second of the intermediate support elements 13 does not extend substantially below the blades 9, the exit opening 91 for the treated material is more open and blocking of the opening 91 is less likely to happen.

(14) The bottom grate 7 is assembled preferably by bolting or by a corresponding prior art demountable method by forcing the outermost curved end support elements 11 of the bottom grate and the blades 9 or blade pieces 9 into a mutual clamping state by means of pulling rods 17 or corresponding elongated members parallel to the axis of rotor 5. The adequate clamping compression is obtained by generating a corresponding tensile stress in said pulling members 17. The ends of the pulling members 17 are fastened to the end support elements 11, which may simultaneously act like intermediate support elements 13 in supporting the blades 9. Fastening of the ends of the pulling members 17 to the end support element 11 is preferably arranged so that the pulling force is adjustable. The pulling members 17 are preferably located close to the blades 9 or blade pieces 9 to minimize distortions of the end support elements 11. Then they direct the pressing force straight from the pulling members 17 to the closest joint between the blade 9 and the end support element 11.

(15) The compression forces between the blades 9 and end support elements 11 are removed by disengaging the fastening of the pulling members 17 to the end support elements 11. Each blade 9 or blade piece 9 may be removed and mounted back between the support elements 11, 13 independently of the other blades 9 or blade pieces 9. Thus, an individual worn or damaged blade 9 or blade piece 9 of the bottom grate 17 can be replaced by releasing one or more of the closest pulling rods 17 and replacing the blade 9 or blade piece 9 with a new one.

(16) The blade 9 or blade piece 9 may be symmetric in at least one direction, for example in its longitudinal axis, so that it is turnable. Then a worn cutting edge 109 can be replaced by an unused cutting edge 109 of the blade or blade piece 9. The same blade 9 or blade piece 9 can be turned and mounted directly in its place and it is ready to operate. The blades 9 or blade pieces 9 may also allow grinding. In that case, worn or otherwise damaged blades 9 or blade pieces 9 can be demounted to be ground and reused either at the same occasion or later. Also, intermediate support elements 13, and end support elements 11 of the bottom grate 7, if damaged, can be replaced as needed even individually.

Other Preferred Embodiments of the Invention

(17) According to another preferred embodiment of the invention, the pulling members 17 are threaded or they are fastened by some other known method that allows tightening to the end support elements 11 of the bottom grate 7. The structure of the end support elements 11 can be arranged substantially stronger than the intermediate support elements 13 if these elements are used to attach the bottom grate 7 to the crusher 1 and they will carry all of the workloads. Advantageously also receiving means 41 can be arranged to the end support elements 11 for moving the whole bottom grate 7. The receiving means 41 may also be used to position and fasten the bottom crate 7 in the crusher 1.

(18) Adaptation of the blades 9 or blade pieces 9 and mounting between the intermediate support elements 13 can be arranged so that the blades 9 or blade pieces 9 are directed and positioned to the intended operation position by means of gravity alone. For this purpose, guidances or grooves or other supporting and guiding means 131 can be arranged in the blades 9 or blade pieces 9 and/or end or intermediate support elements 11, 13 for guiding and/or supporting the blades 9 or blade pieces 9 and the end or intermediate support elements 11, 13 to the intended position in relation to each other. The form-locking guidances or grooves or other supporting and guiding means 131 also makes the joints and the whole structure more robust. This is seen in more detail in FIGS. 3b and 3c, which illustrates the arrangement of individual blade pieces 9 in relation to the end and intermediate support elements 11, 13.

(19) As to the pulling means 17, the arrangement also provides several possibilities. Threaded rods 17 can be arranged to travel between the intermediate support elements 13 freely or be supported in a suitable way in connection with slots or holes 137 and they can also be utilized in positioning and supporting the blades 9 or blade pieces 9 and the intermediate support elements 13.

(20) The pulling members 17 may also be arranged so that the pulling force is produced between two intermediate support elements 11 or with one intermediate support element and one 11 intermediate support element 13. Then an individual blade 9 or all of the blades 9 do not need to be placed and pressed between the end support elements 11 and they can be shorter than the full distance between the end support elements 11. Also the pulling members 17 may be shorter then. If threaded bars 17 with a full length threading are used, nuts 15 aside the two support elements 11, 13 in question can be used to create pulling force between the two support elements 11, 13. Then a pulling force can also be directed to fasten any single blade piece 9 between two support elements 11, 13 when a blade 9 consists of two or more blade pieces 9. Then for example loosing one blade piece 9 of blade 9 between two support elements 11, 13 in a collision does not affect the fastening of the other blade pieces 9 of the same blade 9.

(21) Using threaded bars 17 with a full length threading, nuts 15 in other places than outside the end support elements 11 need some space to be turned and the threaded bars cannot directly contact to and support the blades 9. If threaded bars 17 are then used to position or support the blades 9 or blade pieces 9, suitable sized tubes may be arranged on the threaded bars 17 to provide contact to and to support the blades 9 or blade pieces 9.

(22) The crusher 1 may be provided as illustrated in FIGS. 1 and 2 with means 31 for moving the upper part 3b of the crusher 1 body 3 in vertical direction to create space to facilitate the removal of the bottom crate 7.

(23) Suitable fastening means (not shown) are arranged for the bottom grate 7, by means of which the grate is fastened in its place in the crusher 1 during operation. When the bottom grate 7 is removed from the crusher, the fastenings are released. Service openings 33 are arranged in the stationary body 3 of the crusher 1, through which the bottom grate 7 can be drawn out substantially horizontally in the direction of the axis of the rotor 5.

(24) Although the above description relates to an embodiment of the invention that is in the light of present knowledge considered the most preferable, it is obvious to a person skilled in the art that the invention can be modified in many different ways within the broadest possible scope defined by the appended claims alone.