CRUSHER

Abstract: The invention relates to a crusher comprising a main shaft (1), which is placed into a bore (18) of a rotatable eccentric shaft, the main shaft (1) having a central axis (A) which is inclined in respect of the axis of rotation (B) of the eccentric shaft, and a first crushing head (2), which is attached to the main shaft (1) and rotatable by the main shaft (1) in respect of a second crushing head (3) so that constrained stroke motion is effected between the first crushing head (2) and the second crushing head (3). The inclination of the central axis (A) of the main shaft (1) can be changed in respect of the axis of rotation (B) of the eccentric shaft such that the magnitude of the constrained stroke motion changes.

Description: CRUSHER BACKGROUND OF THE INVENTION The invention relates to a crusher comprising a main shaft, which is placed into a bore of a rotatable eccentric shaft, the main shaft having a cen- tral axis which is inclined in respect of the axis of rotation of the eccentric shaft, and a first crushing head, which is attached to the main shaft and rotatable by the main shaft in respect of a second crushing head so that constrained stroke motion is effected between the first crushing head and the second crushing head, whereby material can be crushed between the first crushing head and the second crushing head, whereby the eccentric shaft comprises an outer eccentric shaft with a second bore and an inner eccentric shaft, which is at least partly positioned so as to be continuously turnable in respect of the outer eccentric shaft in said second bore, whereby the bore is in the inner eccentric shaft, and whereby the inner eccentric shaft and the outer eccentric shaft are turnable in respect of each other by means of gear transmission so that the inclination of the central axis of the main shaft changes in respect of the axis of rotation of the eccentric shaft such that the length of the constrained stroke motion changes. Such an arrangement for adjusting the value of constrained pendu- lous motion, i.e. stroke, is previously known, in which an eccentric shaft is carried by an eccentric bearing. By turning this eccentric bearing, the stroke can be adjusted. In this kind of solution, the stroke is adjusted stepwise, since there is a wedge groove on the outer surface of the eccentric bearing, keeping the eccentric bearing in place by means of a corresponding safety wedge such that the eccentric bearing cannot rotate during the rotating motion of the eccentric shaft. If the bearing were able to rotate, the stroke would change during the rotation of the eccentric shaft. Such an arrangement for adjusting stroke is also previously known, in which the entire eccentric bearing is replaced by a different kind of eccentric bearing effecting a different stroke. Furthermore, in this kind of known arrangement the stroke adjustment always requires the dismantling of the crusher. A solution to this problem is described in the publication US 5,718,391 , from which a crusher according to the preamble of claim 1 is known. This publication discloses a stroke adjusting apparatus, wherein an outer eccentric shaft comprises a worm shaft turnable by means of a hydraulic motor, the worm shaft being arranged to co-operate with toothing on the outer surface of the inner eccentric shaft such that the inner eccentric shaft can be turned in the outer eccentric shaft. This solution thus allows the stroke adjust- ment without having to dismantle the crusher. A disadvantage of this solution is, however, that a worm gear and a hydraulic motor required for turning the eccentric shafts in respect of each other are machine elements that require a lot of space. Thus, the eccentric shaft and thereby the crusher frame have to be dimensioned much bigger than would otherwise be necessary. Due to this, the total weight of the crusher and its manufacturing costs increase considerably. Furthermore, the crusher disclosed in the publication US 5,718,391 has the problem that a hydraulic fluid needed in the stroke adjustment of the crusher has to be distributed through the outer eccentric shaft in rotating mo- tion to the hydraulic motor while the crusher is in operation. Under dusty conditions of a crushing plant it is very difficult to make this kind of arrangement such that it does not leak. BRIEF DESCRIPTION OF THE INVENTION The invention relates to a crusher which solves the problems de- scribed above. The crusher according to the invention is characterized in that the gear transmission comprises a first cog wheel attached to the inner eccentric shaft, a second cog wheel attached to the outer eccentric shaft, and a turning mechanism for turning the first cog wheel and the second cog wheel in respect of each other such that the inner eccentric shaft and the outer eccentric shaft turn in respect of each other. Thus, the internal stroke adjustment arrangement of the crusher is entirely mechanical in the solution according to the invention. The preferred embodiments of the crusher according to the inven- tion are disclosed in the dependent claims. The invention is based on the eccentric shaft comprising two parts, the outer eccentric shaft and the inner eccentric shaft inside it. The first cog wheel is attached to the inner eccentric shaft and the second cog wheel is attached to the outer eccentric shaft. By turning the first cog wheel and the sec- ond cog wheel in respect of each other by means of the turning mechanism, the inner eccentric shaft and the outer eccentric shaft turn in respect of each other. With this arrangement the inclination of the central axis of the main shaft can be changed in respect of the axis of rotation of the eccentric shaft such that the value of said constrained pendulous motion, i.e. the stroke, changes. The crusher according to the invention provides the advantage that the stroke can be adjusted without dismantling the crusher. The arrangement according to the invention also enables a continuous stroke adjustment within a range of 0 to 40 mm, for example. BRIEF DESCRIPTION OF THE DRAWINGS The invention will now be described in greater detail in connection with the preferred embodiments, with reference to the attached drawings, in which Figure 1 schematically shows a sectional side view of a gyratory crusher, the gyratory crusher comprising a hydraulic adjustment apparatus for narrowing a gap between a first and a second crushing head, Figure 2 schematically shows a sectional side view of a gyratory crusher having a different kind of hydraulic adjustment apparatus than the gy- ratory crusher shown in Figure 1 , Figure 3 schematically shows a sectional side view of a cone crusher, Figure 4 schematically shows a sectional side view of a cone crusher having a turning arrangement for turning an outer eccentric shaft in respect of an inner eccentric shaft, Figure 5 schematically shows a top view of a detail of the gyratory crusher of Figures 1 to 3, Figure 6 schematically shows a sectional side view of the gyratory crusher detail of Figure 5, Figure 7 schematically shows a top view of a detail of the gyratory crusher of Figure 4, Figure 8 schematically shows a sectional side view of the gyratory crusher detail of Figure 7, and Figures 9 to 16 show various solutions to adjust constrained stroke motion. DETAILED DESCRIPTION OF THE INVENTION Figures 1 , 2 and 4 show a gyratory crusher with a main shaft 1 , which is placed into a bore 18 of a rotatable eccentric shaft (not marked with a reference number), the bore preferably being an inclined bore. In like manner, Figure 3 shows a cone crusher. The main shaft 1 has a central axis A, which is inclined in respect of the axis of rotation of the eccentric shaft. Since the main shaft 1 is in the bore 18 of said eccentric shaft, the main shaft 1 and its central axis A are inclined in respect of the axis of rotation B of the eccentric shaft. The crusher comprises a first crushing head 2, which is attached to the main shaft 1 and rotatable by the main shaft 1 in respect of a second crushing head 3 so that constrained pendulous motion, or stroke motion, is effected between the first crushing head 2 and the second crushing head 3. During a working cycle the bore 18 of the eccentric shaft effects said con- strained pendulous motion of the first crushing head 2, which constrained pendulous motion narrows and enlarges the gap (not marked with a reference number) between the first crushing head 2 and the second crushing head 3 and effects the crushing of the material (not shown) to be crushed. The first crushing head 2 and the second crushing head 3 in Fig- ures 1 to 4 are mainly cone-shaped crushing heads. The eccentric shaft comprises an outer eccentric shaft 4 with a second bore (not marked with a reference number) and an inner eccentric shaft 5 which is at least partly positioned so as to be continuously turnable in said second bore. The bore 18, in which the eccentric shaft at least partly is, is in the inner eccentric shaft 5. By turning the inner eccentric shaft 5 and the outer eccentric shaft 4 in respect of each other, the inclination of the central axis A of the main shaft 1 can be changed in respect of the axis of rotation B of the eccentric shaft such that the value of said constrained pendulous motion changes. This is because the relative position of the central axis of the bore 18 and the axes of rotation B of the eccentric shaft 1 change. If the central axis of the bore 18 is on the axis of rotation B of the eccentric shaft, the central axis A of the main shaft 1 is at the same location as the axis of rotation B of the eccentric shaft, wherefore there occurs no stroke motion. If the central axis of the bore 18 is taken farther off from the axis of rotation B of the eccentric shaft, the stroke becomes longer. Simultaneously the inclination of the central axis A changes in respect of the axis of rotation B of the eccentric shaft. The adjustment of constrained stroke motion can for example be implemented such that while the inner eccentric shaft 5 moves half a circle in respect of the outer eccentric shaft 4, the inclination of the central axis A of the main shaft 1 changes in respect of the axis of rotation B of the eccentric shaft from the maximum to the minimum. In this case the stroke change can equal to 0 to 40 mm, for example. The crusher further comprises gear transmission (not marked with a reference number) to turn the inner eccentric shaft 5 and the outer eccentric shaft 4 in respect of each other such that the inclination of the central axis A of the main shaft 1 changes in respect of the axis of rotation B of the eccentric shaft, as a result of which the value of the constrained stroke motion changes. This gear transmission is preferably also arranged to keep the inner eccentric shaft 5 in a non-rotating manner in place in respect of the outer eccentric shaft 4. The gear transmission comprises a first cog wheel 6 attached to the inner eccentric shaft 5 and a second cog wheel 11 attached to the outer eccentric shaft 4. The gear transmission further comprises a turning mechanism (not marked with a reference number) for turning the first cog wheel 6 and the second cog wheel 11 in respect of each other such that the inner eccentric shaft 5 and the outer eccentric shaft 4 turn in respect of each other. It is also possible that the first cog wheel 6 is a gear ring (not shown) which does not entirely surround the inner eccentric shaft 5 and/or the second cog wheel 11 is a gear ring (not shown) which does not entirely surround the outer eccentric shaft 4. In a first preferred embodiment according to the invention, which is shown in Figures 1 to 3, for example, and a detail of which is shown enlarged in Figures 5 and 6, said turning mechanism comprises a third cog wheel 7 with external toothing 8 and internal toothing 9. The internal toothing 9 of the third cog wheel 7 is arranged to co-operate with the first cog wheel 6. There is also a control cog wheel 10, which is arranged to co-operate with the external toothing 8 of the third cog wheel 7. The inner eccentric shaft 5 can thus be turned in said second bore of the outer eccentric shaft 4 by turning the control cog wheel 10 in another direction and/or with another speed than the drive gear 12. Alternatively the turning mechanism can consist of the external toothing 8 in the third cog wheel 7, for example, the external toothing cooperating with a worm shaft (not shown). There are also other possibilities, the third cog wheel 7 can for example be turned by means of a motor (not shown) in connection with it, which for example directly affects the external gear 8 of the third cog wheel 7. The third cog wheel 7 can also be turned by means of a hydraulic system (not shown). In a second embodiment of the solution according to the invention, which is shown for example in Figure 4 and a detail of which is shown en- larged in Figures 7 and 8, said turning mechanism comprises a control cog wheel 10 arranged to co-operate with the second cog wheel 11 attached to the outer eccentric shaft 4. The turning mechanism of Figures 7 and 8 also comprises the third cog wheel 7 with the external toothing 8 and the internal toothing 9 which is arranged to co-operate with the first cog wheel 6. Thus, the outer eccentric shaft 4 can be turned in respect of the inner eccentric shaft 5 by turning the control cog wheel 10 in another direction and/or with another speed than the drive gear 12. In the solutions according to the figures, the control cog wheel 10 is preferably mounted on a control shaft 13. By using the third cog wheel 7 by means of the drive gear 12 and the second cog wheel 11 by means of the control cog wheel 10 in the same direction and substantially at the same speed, the eccentric shaft consisting of the inner eccentric shaft 5 and the outer eccentric shaft 4 is made to rotate by means of operating means (not shown) in the solution according to Figures 6 and 8, such that said constrained pendulous motion is effected between the first crushing head 2 and the second crushing head 3. In the figures the control cog wheel 10 and the drive gear 12 are positioned substantially concentrically. For example, in the solution shown in Figure 6, which relates to Figures 1 to 3, the control cog wheel 10 is mounted on the control shaft 13, which is hollow. The drive gear 12 is mounted on a drive shaft 14, which is in the control shaft 13. The control shaft 13 and the drive shaft 14 are substantially coaxial. Figure 8 shows a solution which relates to Figure 4. In the solution according to Figure 8 the drive gear 12 is mounted on a drive shaft 14, which is hollow. The control cog wheel 10 is correspondingly mounted on the control shaft 13, which is in the drive shaft 14. The control shaft 13 and the drive shaft 14 are substantially coaxial. In the figures, a drive belt pulley 31 is mounted on the drive shaft 14. Alternatively the drive shaft can be rotated in some other way. In the solution shown in the figures, the control cog wheel 10 and the third cog wheel 7 form a bevel gear pair. The second cog wheel 11 and the drive gear 12 also form a bevel gear pair in the figures. Preferably the crusher also comprises a control unit 15 by which the reciprocal ratio of rotation and/or rotational speed of the control cog wheel 10 and the drive gear 12 or those of the control shaft 13 and the drive shaft 14 can be changed such that the stroke changes. The crusher preferably comprises an element for limiting the maximum rotational angle (not marked with a reference number) which is adapted to limit the maximum rotational angle between the inner eccentric shaft 5 and the outer eccentric shaft 4. In the crusher shown in Figure 5, the third cog wheel 7 comprises a groove 34, in which there is a stop pin 35, which is attached to the second cog wheel 11 attached to the outer eccentric shaft 4 and which prevents the reciprocal motion, i.e. rotation, of the inner eccentric shaft 5 and the outer eccentric shaft 4, if necessary. In Figure 5, the groove 34 and the stop pin 35 form the element for limiting the maximum rotational angle. The groove 34 can alternatively be formed for example in the inner eccentric shaft 5, the outer eccentric shaft 4 or the second cog wheel 11 , in which groove the stop pin 35 attached to the outer eccentric shaft 4, the inner eccentric shaft 5 or the third cog wheel 7 correspondingly moves. In the crusher according to Figures 1 and 4, there is a bearing 36, which may for example be cylindrical or spherical (as in the figure), between the inner eccentric shaft 5 and the main shaft 1. A spherical bearing allows the main shaft 1 to be properly positioned. Figures 9 to 16 show various control unit solutions 15. The solutions shown in Figures 9 to 14 and 16 are such that the reciprocal ratio of rotation of the control cog wheel 10 and the drive gear 12 can be adjusted either when the crusher is in operation (with and/or without a load) or when it is at a standstill. The adjustment with the solution shown in Figure 15 requires that the crusher is at a standstill. In a control unit solution according to Figure 9, operating means 19, e.g. a hydraulic or an electric motor, using cog wheels or chains rotating the control shaft either directly or, as in Figure 9, by means of a planetary gear 20, are attached to a drive belt pulley 31. The operating means 19 are preferably provided with either an integrated or external brake (not shown), the purpose of which is to prevent the control shaft 13 from unintentionally rotating in re- spect of the drive shaft 14. In a control unit solution shown in Figure 10, worm gear transmission 21 , which is arranged to co-operate with the control shaft 13 such that the control shaft can be turned by means of the worm gear transmission 21 , is attached to the drive belt pulley. In the worm gear transmission 21 according to Figure 10 there is a worm (not marked with a reference number) which is used by operating means (not marked with a reference number), preferably by a small electric or hydraulic motor. The control shaft 13 can be rotated simultaneously by several this kind of worm gear transmissions 21. In a control unit solution shown in Figure 11 , operating means 22, which are preferably a small electric or hydraulic motor, adapted to co-operate with a cog wheel 23, are attached to the drive belt pulley. The cog wheel 23 in turn is arranged to co-operate with a second cog wheel 24 mounted on the control shaft 13 such that the control shaft 13 can be turned by means of the operating means 22. A control solution shown in Figure 12 differs from the above described in such a manner that control power that is supplied from outside the crusher and that rotates a control shaft 13 is linear. Therefore, an internal spiral grooving 38 is made on the control shaft 13. When a control rod 25 is pulled and pushed in a groove (not marked with a reference number) of the drive shaft 14, a slide 27 attached to the control rod slides in the spiral groove 38 of the control shaft 13 and thereby forces the control shaft 13 to rotate. Control power can be generated for example by means of a hydraulic or pneumatic cylinder 26, which rotates along with the control shaft 13. In a control solution shown in Figure 13, control power that is sup- plied from outside the crusher and that rotates a control shaft 13 is also linear. For this purpose, an internal spiral grooving 38 is made on the control shaft 13 according to the figure. When a control rod 28 is pulled and pushed, a slide 27 attached to the control sleeve slides in the spiral groove 38 of the control shaft 13 and thereby forces the control shaft 13 to rotate. Control power can be generated for example by means of a hydraulic or pneumatic cylinder 29, which is pivoted to the control sleeve 28 and a drive belt pulley 31 and which is attached to the crusher frame by means of a fastening element 39 such that the cylinder 29 does not rotate while the crusher is in operation. In a control unit solution shown in Figure 14, a control shaft 13 is turned by means of a separate drive belt pulley 30 which can be synchronized with a drive belt pulley 31 of a drive shaft 14. These drive belt pulleys 30 and 31 can either be on the same or on a different axis. The reciprocal speed of the drive shaft 14 and the control shaft 13 (the stroke of the crusher) is changed by rotating the above mentioned drive belt pulleys 30 and 31 at a speed differing from each other. The speed of the drive belt pulleys 30 and 31 can be synchronized to be the same, when the stroke is not changed. In a control unit solution shown in Figure 15 a cog wheel 10 is turned when the crusher is at a standstill. In the solution according to this figure, a control shaft is rotated manually or by means of a handle 32 and it is locked in its place for example by means of pins 33 to be mounted in different bores. Instead of the pin 33, the solution according to Figure 15 may comprise a brake mechanism or the like (not shown in the figures) which locks a drive shaft 14 and the control shaft 13 in respect of each other. Figure 16 shows a control solution of the crusher according to Figure 4. In this solution a control shaft 13 is placed inside a hollow drive shaft 14. The control shaft is rotated in respect of the drive shaft by means of a motor 40 placed at the end of the control shaft by means of a gear, the motor being able to rotate along with the drive shaft when the crusher is in operation. A brake motor which locks to be non-rotating when no energy is fed thereto is the most suitable for the purpose. Thus no separate locking mechanism is re- quired between the control shaft 13 and the drive shaft 14 to prevent their reciprocal motion. The crusher according to Figure 9 is preferably provided with a rotational angle indicator 37, e.g. a stepping motor. This rotational angle indicator 37 is adapted to directly measure the rotational angle between the inner eccentric shaft 5 and the outer eccentric shaft 4 or to monitor the relative position of the elements controlling the rotational angle between the inner eccentric shaft 5 and the outer eccentric shaft 4, i.e. the relative position of the turning mechanism or gear transmission parts. The crusher shown in Figure 1 further comprises a hydraulic ad- justment apparatus for changing the lowest value of the gap between the first crushing head 2 and the second crushing head 3, i.e. for adjusting the crusher. The adjustment is changed by means of a hydraulic adjustment apparatus by supplying a pressurized medium to a space 17 below a control piston 16, whereby the first crushing head 2 rises and thereby reduces the adjustment. Correspondingly, by removing pressurized medium from the space 17, the first crushing head 2 moves down and the adjustment enlarges. The piston has an open-top cylinder shape. The lower end of the main shaft 1 rests against the bottom of the cylinder on a bearing element. Such a hydraulic control apparatus is described in the publication EP 0 408 204 B1 , for example. The gyratory crusher shown in Figure 2 comprises a different kind of hydraulic control apparatus for changing the lowest value of the gap between the first crushing head 2 and the second crushing head 3, i.e. to adjust the crusher. In the crusher according to Figure 2, a control piston 16 is entirely below the main shaft 1. It is obvious to a person skilled in the art that as technology devel- ops, the basic idea of the invention can be implemented in various ways. The invention and its embodiments are thus not restricted to the above described examples but may vary within the scope of the claims.

Claims: CLAIMS 1. A crusher comprising a main shaft (1 ), which is placed into a bore (18) of a rotatable eccentric shaft, the main shaft (1 ) having a central axis (A) which is inclined in respect of the axis of rotation (B) of the eccentric shaft, and a first crushing head (2), which is attached to the main shaft (1 ) and rotatable by the main shaft (1) in respect of a second crushing head (3) so that constrained stroke motion is effected between the first crushing head (2) and the second crushing head (3), whereby material can be crushed between the first crushing head (2) and the second crushing head (3), whereby the eccentric shaft comprises an outer eccentric shaft (4) with a second bore and an inner eccentric shaft (5), which is at least partly positioned so as to be continuously turnable in respect of the outer eccentric shaft (4) in said second bore, whereby the bore (18) is in the inner eccentric shaft (5), and whereby the inner eccentric shaft (4) and the outer eccentric shaft (5) are turnable in respect of each other by means of gear transmission so that the inclination of the central axis (A) of the main shaft (1) changes in respect of the axis of rotation (B) of the eccentric shaft such that the length of the constrained stroke motion changes, c h a r a c t e r i z e d in that the gear transmission comprises a first cog wheel (6) attached to the inner eccentric shaft (5), a second cog wheel (11 ) attached to the outer eccentric shaft (4), and a turning mechanism for turning the first cog wheel (6) and the second cog wheel (11 ) in respect of each other such that the inner eccentric shaft (5) and the outer eccentric shaft (4) turn in respect of each other. 2. A crusher as claimed in claim ^ c h a r a c t e r i z e d in that the turning mechanism comprises a third cog wheel (7) with external toothing (8) and internal toothing (9) which is arranged to co-operate with the first cog wheel (6), that it comprises a control cog wheel (10), which is arranged to cooperate with the external toothing (8) of the third cog wheel (7), and that the inner eccentric shaft (5) is turnable in said second bore by turning the control cog wheel (10). 3. A crusher as claimed in claim 2, characterized in that the control cog wheel (10) is mounted on a control shaft (13), which is hollow, that it comprises a drive gear (12), which is arranged to co-operate with the second cog wheel (11) and which drive gear (12) is mounted on a drive shaft (14) which is at least partly in the control shaft (13), and that the control shaft (13) and the drive shaft (14) are substantially coaxial. 4. A crusher as claimed in claim ^characterized in that the turning mechanism comprises a control cog wheel (10) arranged to co-operate with the second cog wheel (11), that the turning mechanism comprises a third cog wheel (7) with external toothing (8) and internal toothing (9) which is arranged to co-operate with the first cog wheel (6), and that the outer eccentric shaft (4) can be turned in respect of the inner eccentric shaft (5) by turning the control cog wheel (10). 5. A crusher as claimed in claim 4, characterized in that it comprises a drive gear (12), which is arranged to co-operate with the third cog wheel (7) and which drive gear (12) is mounted on a drive shaft (14), which is hollow, that the control cog wheel (10) is mounted on the control shaft (13), which is at least partly in the drive shaft (14), and that the control shaft (13) and the drive shaft (14) are substantially coaxial. 6. A crusher as claimed in claim 2 or 4, characterized in that it comprises a control unit (15), by which the reciprocal ratio of rotation of the control cog wheel (10) and the drive gear (12) can be changed. 7. A crusher as claimed in claim 3 or 5, characterized in that it comprises a locking device (33) for locking the control shaft (13) in respect of the drive shaft (14). 8. A crusher as claimed in any one of claims 1 to 7, characterized in that there is a bearing (36) between the inner eccentric shaft (5) and the main shaft (1 ). 9. A crusher as claimed in any one of claims 1 to 8, characterized in that it comprises an element for limiting the maximum rotational angle, which is adapted to limit the maximum rotational angle between the inner eccentric shaft (5) and the outer eccentric shaft (4). 10. A crusher as claimed in any one of claims 1 to 9, characterized in that the rotational angle between the inner eccentric shaft (5) and the outer eccentric shaft (4) can be monitored by a rotational angle indicator (37).

Inventors: SAVOLAINEN REIJO, SAVOLAINEN, REIJO
Applicants: NORDBERG LOKOMO OY, SAVOLAINEN REIJO, NORDBERG-LOKOMO OY, SAVOLAINEN, REIJO
Application year: 2000
Main classification: B02C2
IPC codes: B02C2