Known technologies and their shortcomings and disadvantages Among the first developments of the cone crusher is the apparatus described in US patent 1,353,077, in which a long shaft has been attached to the lower part of the cone and immediately under the cone there is a radial bearing, which allows the angular tilting of the shaft.

When the lower part of the shaft is rotated by the eccentric, a primitive crushing action is created between the cone and the mantle. The shortcomings of this apparatus are the defects in the crushing move- ment and its high structure.

In US patent 1,570,970 the support for the upper part of the cone is accomplished with a vertical shaft and the crushing action is achieved with an eccentric bearing arrangement at the lower part of the cone.

Thus the crushing action is uncontrollable at its upper part and its sup- port causes great forces to the eccentric bearing. The height of the crusher is, however remarkably low. In US patent 1,628,619, the support of the cone has been improved in the vertical direction, but in other respects, as to its principles and disadvantages, it is similar to the patent 1,353,077, for example because of the very high structure.

Notable success was the US patent 1,791,584 from the year 1931, whose inventor E. B. Symons left behind a well known trademark bearing his name. The trade mark is well known even today. Most of the cone crushers in use today are very similar to the Symons rnodel.

In this crusher the weight of the cone and the vertical crushing forces are received by a spherical bearing built inside the cone. This particular bearing type allows also the eccentric crushing motion of the cone.

Further, the crushing action is achieved by the shaft that extends from the upper part of the cone well below the cone and which shaft is

moved along a circular path by a large eccentric bushing so that the desired crushing motion is obtained. In this crusher the setting adjust- ment is already described so that the mantle part is rotated via the threads provided in the mantle and the crusher frame so that mantle moves up or down, depending on the direction of the rotation, and the crusher setting, (minimum distance of the mantle to the cone) decreases or increases. This method also compensates for the wear of the crushing surfaces of the cone and the mantle. This patent also describes the springs, which carry the crushing forces directed to the mantle. These springs also function as an overload protection in cases, when, for example, a piece of steel larger than the setting enters into the crusher. In Symons-crushers slide bearings are used to receive the horizontal forces caused by the crushing movement and crushing forces. Slide bearings are naturally expensive and cause a consider- able lubrication need and power and energy loss because of the warming of the lubrication and the need to cool it down.

Additional disadvantages of the Symons-crusher are its height and quite large weight, caused by the fact that a large part of the crusher's height is caused by the eccentric shaft, eccentric bearing and their drive devices, which extend well below the cone. Despite these obvi- ous shortcomings, this method is a principle that has prevailed as the leading one till these days. Many inventions have been made to try to eliminate its individual shortcomings, among other things through patents mentioned below.

US patent 2,579,239 describes a cone crusher in which the slide bear- ings, carrying crushing forces, have been replaced with roller bearings.

Roller bearings are immediately below the cone. The eccentric bush- ing, which creates the crushing movement, is still with slide bearings.

In US patent 3,372,881, a spherical bearing, which supports the cone and carries the vertical forces, is mounted inside the cone, in its upper part, and the eccentric bearing is above the primary drive shaft, partly even inside the cone, so that the height has been reduced a little bit.

The advantages are, however, quite limited because the eccentric shaft

must still be quite long so that it could withstand the bending forces caused by the crushing.

In US patent 4,779,808, an attempt is made to replace the high eccen- tric shaft with a gear wheel assembly creating the eccentric motion, but it has also failed and the patent has been allowed to expire.

In US patent 5,190,229 there is a similar solution as in the US patent 2,579,239, but the bearings have been placed differently, into the top and bottom of the eccentric shaft. Vertical forces are also carried by the same bearings. It has been possible to eliminate the slide bearings of the eccentric as well. The crusher is otherwise a typical Symons ; this patent is the patent of the bearing manufacturer in order to improve the Symons crusher with new bearings. US patent 5, 718, 390 is also quite similar to the previous one except that the bearing is a large spherical roller bearing, which allows-movement of the vertical eccentric shaft. In this solution the vertical forces are carried by the spherical bearing.

The height is reduced, but bearing arrangements are still needed for both the vertical and horizontal directions.

In US patent 5,350,125 the high eccentric shaft has been eliminated by placing the cone on a crosswork support by arranging a ring outside of the body of the crusher, the ring having the supporting surfaces for vertical and horizontal directions. A drive ring, which is rotated in the ring is eccentric horizontally and has variable thickness in vertical direction, (low and high section on opposite sides). When the ring is rotated and the crosswork supporting the cone is mounted on the drive ring, a movement imitating the Symons crusher is obtained for the crosswork together with the cone. The origin of the movement is above the cone, centrally of it. When this solution is examined, it can be noted, that two different places are now needed against both the verti- cal and horizontal forces, the first one between the fixed ring and the drive ring and the second one between the drive ring and the cross- work. This means that the solution is in this respect more difficult than the one in the traditional Symons-crusher. Moreover, the difficulties now lie in the bearing surfaces, which have a larger diameter than the body of the crusher. These bearings must be lubricated and protected

from dust. The crushing movement cannot be adjusted in this solution either. The only advantage, which can be obtained, compared to the Symons crushers, is the savings in height and probably in the weight also. Other advantages are hard to find and this method has not been successful.

In all the patents mentioned, except in the first and oldest one, the pri- mary shaft has been more or less below the cone in a horizontal posi- tion. They have also required a large and expensive bevel gear trans- mission from the horizontal primary shaft to the vertical eccentric shaft.

In the US patent 5,810,269 is described a structure, in which the pri- mary drive shaft is a vertical shaft while the drive wheel is located above the cone and the drive shaft is mounted on it's own bearings below the drive wheel. Use of the bevel gear transmission can be avoided with this method. The use of the Symons. type long eccentric shaft can be avoided in this method, because the eccentric has been designed in the upper part of the cone, inside it, where also the bearing arrangement is provided. The lower part of the cone is furnished with a spherical bearing, which carries both vertical and-horizontal forces.

Because the spherical bearing is in the lower part of the cone and it doesn't allow any other movement except the angular change of the shaft and the eccentric shaft is in the upper part of the cone, the crushing movement of the crusher is different from the Symons-crush- ers. In the upper part the crushing motion is composed of eccentric motion, in the lower part of the angular change of the shaft with the centre of the spherical bearing as origin, so that the circumference of the cone in a sort of way rises upwards against the mantle with a rotating motion. At the lower part where the diameter increases, the crushing stroke length increases, this being undesirable, because this area is a so-called calibration zone, where crushed product should be made as homogeneous as possible. One of the disadvantages of this method is the feeding of material into the crusher. The drive device centrally on the top obstructs central feeding of material into the crusher. The feeding takes place along a chute laterally of the crusher, which naturally is very disadvantageous, because the crusher should crush evenly through the whole peripheral length of the cone and the mantle.

All the above-mentioned crushers are mechanical and based on the eccentric circular crushing motion. The crushing stroke in these crushers is thus constant and the crushing motions in the upper and lower parts have always the same sequence compared to each other.

The so-called crushing ratio, gap between the cone and mantle in the upper section of the crushing chamber on the"closed"side compared to the corresponding gap in the lower section, cannot be changed in them either, unless wear parts of the cone and/or mantle are changed.

The crushing motion created by the eccentric is not optimum either, not directly compressive, but oblique against the mantle, wearing more the wear parts and creating more fine"stone dust"which usually is unde- sirable. So the adjustment capabilities of the cone crushers, made according to the present state of the art are poor, and only the adjust- ment of speed is possible. The mechanical eccentric does not protect from overload. That's why overload protection usually is arranged with springs in the mantle and in some models with pressure supports under the eccentric shaft. Further, this type of crusher also has the tendency-to spin the cone around the eccentric shaft, which is disad- vantageous. One of the shortcomings in at ! the above-described crusher types is the expensive bearing and their protection from dust and dirt. There have been attempts to eradicate these problems with different methods, both patented and not patented, for example several patents relate to bearing sealing.

Further ; publications DE 1157459, US 3666188 and US 2291910 dis- close crushers where the eccentric movement is accomplished with an array of units distributed throughout the circumference, several units of them being activated in turn.

Summary of the invention The purpose of the invention is to eliminate the drawbacks previously mentioned and to present a crusher, which can attain remarkable improvements in cone crusher technology, benefits in operation char- acteristics of the crushers and savings in structures. To obtain these

benefits, the main characteristics of the crusher according to the inven- tion are those which are presented in the characterizing clause claim 1.

The mentioned benefits are attained with following solutions: Mechanical power transmission, drive shaft, bevel gear and eccentric shaft are entirely abandoned and replaced with actuators, most natu- rally with hydraulic cylinders, functioning between the body of the crusher or mantle and the cone functioning as the inner crushing mem- ber. The pressure of hydraulic fluid is led into the cylinders so that the crushing cavity on different sides is narrowed and widened, (the rela- tive position of mantle and cone to each other is changed), by the cyl- inders so that the crushable materials in the annular crushing cavity between the cone and the mantle are crushed when they come closer to each other, and the material can fall down when they move away from one another. The optimal crushing is naturally obtained, when the cone has a similar movement as in an eccentric driven crusher, in other words the periphery of the cone has a circular track, so that the mate- -rial is crushed as evenly as possible around the complete discharge cavity.-This kind of motion can be obtained using known proportional valves, when, for example, with operation of at least two valves the amount of oil is adjusted in a right proportion between two adjacent cylinders and after that again for the following two adjacent cylinders until the complete round has been finished. After that a new round can be started. In the method in question also the mantle can perform the crushing motion, in which case the cone could be stationary. This application also makes it possible for both of them being freely sup- ported, because their mutual motion and position define the crushing.

To create the crushing force cylinders on the opposite sides of the cone (or the mantle) can be used, (the others pulling and, correspond- ingly, the ones on the opposite side pushing), this meaning that the force needed from one cylinder is approximately halved and also the crushing forces directed on the structures are distributed to opposite sides of the crusher.

In addition to the parts mentioned above, the design of this invention also eliminates expensive bearings, which carry the vertical forces. The

novel crusher becomes therefore constructively considerably cheaper than the traditional Symons-structures or its numerous applications.

When the motion phases of two adjacent actuators are synchronized in a controlled manner with respect to each other, only a few actuators are needed.

The height and the weight of the crusher will be considerably lower, which is a notable advantage especially in the mobile crushing plants, but also in stationary crushing plants. Also the moving masses are much smaller, because the eccentric shaft and bushing can be removed and the cone becomes considerably lighter, because the eccentric shaft does not need to be attached to the cone. The reduction of the dynamic forces is a remarkable added value for mobile crushing plants.

The actual crushing process is improved among other things for fol- lowing reasons: 1) The crushing motion can be made very compressive by directing the cylinders so, that the movement of the cone against, the mantle or the relative movement of the cone and mantle is as perpendicular as possible. In none of the known applications this is possible.

2) With the method in question the crushing motion in the upper part can be arranged to be in a desired"phase shift"with the lower part. For example, if the material is very dry and easy flowing, the crushing in the upper part can take place 90 degrees"in advance"of the the crushing in the lower part meaning that the minimum setting of the lower part advances a quarter of a lap after the minimum setting of the upper part, during which time the easily flowing material can flow just the desired amount downwards for further crushing. If the material does not flow very easily, said phase shift can be for example 180 degrees. This is not possible with any of the known crushers.

3) If there is little need for crushing (small crushing ratio) and homogeneous granular size of crushed material is desired, a 30 mm setting could be used in the upper part and a 10 mm setting in the lower part, so the granular size will be much more even than with"normal"crushing ratios. This is not possible with any of the known crush- ers without the change of the mantle and/or the cone.

4) More even crushed material can be obtained by reduc- ing the eccentricity, i. e. the"stroke". Naturally this change of stroke length is not possible with normal eccentrics, but the international publication WO- 00/21673 describes a method, which is an expensive additional option. The invention described herein gives a possibility to change the stroke length without expensive additional equipment.

5) The running speed of crushers is one of the desired adjustment possibilities. In the present models the adjustment is possible by changing the transmission ratio of \l-belt drives or by adding an adjustable drive in the motor. These methods are either difficult or expen- sive. In hydraulic drive this add-on increases the cost only minimally.

6) In the current, eccentric driven crushers, the mantle part has been fastened to the body with springs. The springs function as an overload protection. When material which cannot be crushed, for example piece of steel or some- thing similar, enters into the crushing chamber and does not pass through it, the springs yield so that the drive device and the crusher are prevented from being dam- aged. When the crushing chamber is emptied, lifting the mantle with several powerful jacks, which have been fastened to the crusher, usually does it. These jacks and the hydraulic unit powering them are expensive addi-

tional equipment. In the method according to the inven- tion, the hydraulic drive can be used both as an overload protection and it can be furnished with manual valves, which can be used to empty the crushing chamber.

7) In the traditional cone crushers the cone has a tendency to start a spinning motion, which is disadvantageous. A method to prevent this spinning is described for example in the US patent 6,065,698. The apparatus described in this invention does not have this tendency at all, so no such add-ons are needed in this respect either.

As evident by the previous text, the method is very economical and diverse drive application for the cone crushers also because of its properties.

Short description of the figures In the following, the invention will be explained more precisely with ref- erences to the enclosed drawings, where Figure 1 presents a cone crusher according the invention in a verti- cal section, Figure 2 presents the crusher of Fig. 1 in a horizontal section along plane A-A in Fig. 1, Figure 3 presents a cone crusher of a second embodiment of the invention in a vertical section, Figure 4 presents the crusher of Fig. 3 in a horizontal section along plane A-A in Fig. 3, Figure 5 presents a cone crusher of a third embodiment in a vertical section,

Figure 6 presents the crusher of Fig. 5 in a horizontal section along plane A-A in Fig. 5, and Figure 7 presents forces of the actuators as a function of the angle of the crushing cycle.

Detailed description of the invention The method can be accomplished in several different ways. Some of the possibilities are described here. To simplify matters, auxiliary appa- ratuses and parts, which are not essential for the invention and are well known technology have been removed from the figures. Also the wearing parts of the mantle and the cone have been left out. Also the hydraulic piping leading to cylinders and the valves which distribute the hydraulic fluid to them and hydraulic units have been left out, because these devices are known technology.

The crusher, in which the invention can be applied, has an inner cone- shaped crushing part, which tapers upward, crushing cone 3, and out- side of it there is a similarly cone-shaped part called the mantle 2. The inner crushing part and the mantle create opposite, in a horizontal sec- tion essentially circular crushing surfaces to crush the material fed be- tween them. Figures 1 and 2 present such variation of cone crusher, in which said mantle 2 has been attached to the outer body 1 of the crusher fixedly or with threads. The threading is possible and needed for example to adjust the setting. According to the invention, the rela- tive movement between the cone 3 and the mantle 2, where the short- est distance between the cone and the mantle circulates along the circumference, that is, along an essentially circular track in a horizontal plane, is attained with actuators effective between the cone and the body. In the embodiment shown in figures 1 and 2, the basic solution is enabled so that for example 4-12 hydraulic cylinders, marked with number 5, are mounted on brackets of the lower part of the cone and lower part of the body, and they create the necessary crushing motion of the cone 3. If cylinders 5 alone are not enough to support the weight of the cone, 3, the upper part of the cone 3 can be supported for ex- ample with a bearing 6, which allows the angular change and which is

supported on the body with girders or similar support structure. The surfaces of the bearing are spherical and the bearing can utilise solu- tions known from cone crushers. The position of the bearing 6 in verti- cal direction affects the length of the crushing motion at different points along the height of the cone.

In the variation shown in figures 1 and 2, the cylinders 5 can be sup- ported, instead of the outer body, on a support structure inside the cone, so that they will not be under the material flow coming from between the cone and mantle and do not need to be protected.

In order to avoid the position of the bearing 6 determining the length of the crushing motion, a mechanism can be built, which lengthens the crushing motion of the upper part of the cone 3. Figures 3 and 4 describe an alternative structure, where there is, for example, a cross- work-like supporting structure 4 under the body of the crusher, over which there is a periphery on which the cylinders 5 have been mounted. Furthermore a higher stand has been built in the middle, which functions as a support structure, on which the upper cylinders 5a driving the upper part of the cone are mounted. The stroke motion is created with the movement of the cone 3, as is the case with contem- porary crushers. The position of the cone 3 in relation to the mantle 2 during the crushing motion is not dependent on a fixed bearing point, but instead it can be freely adjusted by the cylinders 5,5a. This struc- ture enables not only the savings in manufacture but also all the previ- ously described functional advantages; a better directed crushing mo- tion, control of the length of the crushing motion, the control of the crushing ratio, the control of the phase shift of the crushing motion in the upper and lower part of the cone 3, and also the control of the run- ning speed. Also all the hydraulic cylinders are protected under the cone and they can be easily shielded from dust, for example by making the space almost entirely closed and by leading there a small over- pressure of clean air. In figures 3 and 4 a ring 7 inside the cone is also shown. The ring is concentric with the mantle 2 and functions as a stopper securing that the crushing motion of the cone follows a circular track.

Figure 5 presents a new option in the respect that the cone 3 has been built stationary and a thread has been made inside of it. In the figure the cone has been screwed onto a large bushing-like screw 7, so that by rotating the cone 3, the settings can be adjusted and the wear of the wear parts can be compensated for. The screw 7 has been attached to a body 4 and the body 4 has been further fixed to the circular body 1, which together form a fixed entity. In this variation, the crushing motion is created by the movement of the mantle 2 by the cylinders 5 and 5a acting between the stationary body and the mantle 3. As this variation has cylinders in the upper and lower parts of the mantle and each momentary position of the mantle 2 can be adjusted by means of the cylinders without the limitations posed by fixed bearing points, this variation, too, offers all the technological crushing benefits described before. The structure is somewhat more open and more easily serviced than in the embodiment shown in figures 3 and 4. Also in this version there is a ring 7 functioning as stopper, now concentric with the fixed cone 3 and located outside the mantle 2.-From figure 6 we can see that the cylinders 5 do not have to be mounted in radial direction to the . mantle. Instead they can be installed in pairs to the mantle 2, more or less tangentially. Thus, space can be saved in radial direction. A pair of actuators acting on the same point can be thought to act as one actuator in this case.

The cylinders are fixed at their both ends to a fixed part and respec- tively to a movable part, thus enabling the functioning as both pulling and pushing actuators. The fixture is so articulated that the cylinder can pivot in the direction of the circumference of the movable part due to the eccentric movement (for example Figs. 2,4 and 6).

The number of actuators can be optimised by taking into account the control of the crushing motion and the demands created by the control of several actuators. When taking a closer look at the actuators on the circumference of the mantle or the cone, it can be noted that already three of them, equally spaced by angular distances of 120 degrees, can create the desired circular motion. On the other hand there can be more actuators, advantageously with equal distances from each other, that is, at equal angular distances. The optimum amount is dependent

on the size of the crusher, on the crushing forces needed and on the characteristics of the actuators chosen. Next we take a closer look on system of four actuators, especially the function of two actuators next to each other, when the crushing point (the minimum setting between the cone and the mantle) advances a quarter of a lap meaning 90 degrees. This is illustrated in figure 7.

It is essential that the crushing motion advances at even speed between the cone and the mantle. When looking from the centre of the crusher, from its origin, the angular speed of the crushing motion is thus constant. This kind of speed can be obtained for example with proportional valves familiar from hydraulics.

The crushing occurs all along the circumference of the crusher starting from the point where the distance between the mantle and the cone starts diminishing (starting point) and the crushing continues all the way to the point of the minimum setting. For the sake of simplicity and clarity, the point of minimum setting, meaning minimum distance between the cone and the mantle, has. been considered as the crush- ing point, when we examine the circular motion. The crushing force generally-increases from its starting point until it reaches the point of minimum setting, and the total force is the sum of said area. Because with these crushers we are as a matter of fact speaking about the rela- tive movement of two circles of different sizes along a circular path, the crushing takes place over about half the length of the circumference.

On the other half of the circumference the material flows downwards.

This means that the forces needed from different actuators at different stages of the crushing are very different, but they re-occur cyclically in identical forms during every crushing round, if the crushing circum- stances do not change. This gives the possibility to simplify the design of the actuators, or in case of hydraulic cylinders as actuators, their control. Also, for example the requirements set to the properties of a relief valve used as overload protection are such that its opening pres- sure must vary in different phases of the crushing.

In the scheme in figure 7 we look at an example, where two actuators next to each other have been arranged at 90-degree angle to each

other in the direction of the circular crushing motion. In this arrange- ment the"crushing round"consists of four cycles as shown in figure 7.

In the figure we assume that two adjacent actuators, preferably hydraulic cylinders, together produce the needed resultant force, FR. It can be noticed, that when the resultant of the crushing force is in angle of 0 degrees to the first cylinder, this cylinder must produce crushing force F1 equal to the resultant force FR. After this, as the crushing motion advances, the force F1 created by the first cylinder decreases and the force F2 created by the second cylinder next to it increases, so that their resultant force always remains FR. When the crushing point has advanced to a distance of 45 degrees (halfway of the cylinders), F2 becomes greater than F1, and this continues until at 90 degrees F1 becomes zero and F2 equals the resultant force. Cylinders being located on the opposite sides in the direction of the diameter of the cir- cumference can actively contribute to the production of the force during the cycle of Fig. 7, by the same force distribution principle and by action in the same direction, their operation being synchronized with the first and second cylinder.

The cyclic function described above offers the possibility to make a control for the actuators, which enables to keep the constant resultant force FR (crushing force) during the above-described circular move- ment and circular crushing action, but when desired, the resultant force can be adjustable (changeable in magnitude) for each crushing proc- ess. When using actuators operated with pressure medium, the control function is performed by a valve system, which divides the pressure medium (for example hydraulic fluid) from the pressure medium source in correct ratio to the actuators at each moment.

As already mentioned in connection with figure 6, the actuators may also be arranged in pairs, so that they affect the same point on the cir- cumference of the crushing motion. The presentation in figure 7 also applies to this case, when the first cylinder and the second cylinder should be understood as a first cylinder pair and as a second cylinder pair. Each of the cylinders of the same cylinder pair functions identi- cally causing the same force, whose combined effect is the force F1 or F2 changing according to the crushing motion.

Overload protection can be realized in a system utilising a pressure medium with valves in connection with the corresponding actuators.

Then the triggering level of overload (the opening pressure of the overload valve) is dependent on the phase of the cycle, where the allowable maximum crushing force, always of the same magnitude, would result in triggering of the overload protection.

The invention is not restricted to the variations presented above; instead, it can be altered according to the inventive ide given by the enclosed claims. Although pressure medium operated actuators have been discussed above, actuators operable analogically by a power of other kind and synchronizable with respect to each other can also be utilized, these actuators being able to change the distance between the thrust point (body) and the movable part in a controllable manner.