Patent Description:
Crushers, such as cone crushers and gyratory crushers, are used to crush ore or large rocks into smaller rocks, gravel or dust. The crushers can also be used for recycling waste material such as for crushing plastics material into finer particulates. Typically, a crusher has a housing supporting an outer crushing shell and in which is located a crushing head supporting an inner crushing shell. The crushing head is moved to crush the feed ore between the outer crushing shell and the inner crushing shell. The desired size of the finer particulate matter is regulated by setting the minimum width of a crushing gap formed between the outer and inner crushing shells.

One type of cone crusher utilises an eccentric member to cause movement of the crushing head. The shaft of the crushing head is mounted in the eccentric member and, during use, the eccentric member causes the shaft to move along a predefined path to cause movement of the crushing head. Prior art examples of such eccentric drives can be seen in <CIT>, <CIT>, <CIT>, <CIT> and <CIT>. One problem encountered with the use of such an eccentric member is that it is cumbersome to change the predefined path of movement of the shaft - normally this requires the cone crusher to be dismantled so that the eccentric member can be exchanged for another. It is often also difficult to adjust the minimum size of the crushing gap between the housing and the crushing head.

In another type of cone crusher the crushing head rests in a spherical bearing and its shaft is held in a cylindrical sleeve having an unbalanced mass attached thereto. By rotating the cylindrical sleeve, the unbalanced mass is rotated and this causes it to swing radially outwardly due to centrifugal forces acting on the sleeve - which in turn causes the crushing head to gyrate within the spherical bearing. The gyration path (and the crushing gap) can be selectively changed by either altering the speed of rotation of the sleeve, by altering the mass of the unbalanced mass, or by changing the distance between the unbalanced mass and the sleeve. Prior art examples of such unbalanced mass drives can be seen in <CIT> and <CIT>. One problem that may be encountered in using an unbalanced mass is that the rotational movement of the mass causes excessive vibrations in the cone crusher leading in increased wearing of its parts.

<CIT> also discloses a gyratory (inertia) cone crusher equivalent to the above but being further provided with a cavity protection device. Its drive mechanism includes a pulley that drives a transmission shaft so that torque is transmitted to the main shaft of the crushing head, thereby to cause rotation of the unbalanced mass to generate the breaking force. The cavity protection device is in the form of a shock absorber located around the crushing head and configured to prevent the crushing head from directly contacting the crushing shell should the movement of the crushing head become too extreme. It is described that the shock absorbers are preferably elastic rubber air springs, but they can also be hydraulic cylinders. However, these hydraulic cylinders do not impart driving force to the crushing head as any such force would conflict with the breaking force generated by the unbalanced mass.

According to a first aspect of the disclosure, there is provided a crusher for crushing material into finer particulates, the crusher comprising.

The drive mechanism may be configured to generate movement of the crushing head by imparting only a pulling force on the shaft. The crushing head may be supported on a spherical bearing which may include one or more bearing pads. The drive units may be configured to be selectively activated to generate movement of the crushing head relative to the housing. In some embodiments the drive units are located within the housing, whereas in other embodiments the drive units are located outside the housing.

The crusher may include a coupling mounted on the shaft, with each drive unit being joined to the coupling via a tie rod. Each tie rod may be pivotally joined to the coupling and may be pivotally joined to its drive unit. Each tie rod may be joined to the coupling and its drive unit via universal joints or constant-velocity joints.

The crusher may include a counterweight mounted on the shaft, wherein the counterweight is spaced away from the crushing head and wherein the drive units are joined to the shaft between the crushing head and the counterweight. The counterweight may be connected to the shaft and configured to rotate together with the crushing head. Alternatively, the counterweight may be connected to the shaft but configured to rotate independently from the crushing head. In some embodiments the counterweight may be integrally formed with the coupling.

Each of the drive units may be one of a hydraulic cylinder, a linear motor and a solenoid.

When the drive units are hydraulic cylinders, the drive mechanism may include a hydraulic circuit being configured to selectively activate each of the cylinders. The hydraulic circuit may include a proportional directional control valve being configured to control flow of hydraulic fluid into or out from each cylinder. In one embodiment the control valve is a three-position pilot operated proportional directional control valve. The control valve may be configured in a failsafe default configuration to open its tank port and close its pump port.

The hydraulic circuit may be configured that when one of the cylinders is selectively activated, the pulling force exerted by that activated cylinder operates to exhaust hydraulic fluid from other cylinders.

The hydraulic circuit may include a bleed fluid line leading from each cylinder, wherein during use each bleed fluid line is configured to bleed off a portion of hydraulic fluid from its cylinder and wherein the hydraulic circuit is replenished by fresh hydraulic fluid. Such replacement of the portion of the hydraulic fluid may assist in regulating a temperature of the hydraulic fluid in the hydraulic circuit.

Each cylinder may be associated with one or more bearing pads, with each bleed fluid line leading from its cylinder to the bearing pads so that, in use, the portion of hydraulic fluid flowing through the bleed fluid line is ejected between the bearing pads and the crushing head. Each bleed fluid line may lead to a distribution manifold for dispersing hydraulic fluid to any one or more of all the bearing pads. In such case, the crusher may include one-way valves provided between each of the cylinders and the distribution manifold, the valves being configured to prevent hydraulic fluid flowing from the distribution manifold back to the cylinders.

The hydraulic circuit may be operable to adjust a pressure of the hydraulic fluid within the cylinders, thereby to select a desired operational crushing pressure to be exerted by the crushing head during use. The hydraulic circuit may be operable to adjust a volume of the hydraulic fluid within the cylinders, thereby to select a desired operational width of the crushing gap during use.

The crusher may include a positional sensing mechanism being configured to determine an operative position of the crushing head within the housing. The positional sensing mechanism may be any one of (a) each drive unit being a position sensing drive unit configured to detect a position of its actuator; (b) a proximity sensor being associated with each drive unit, wherein the proximity sensors are configured to detect the proximity of the shaft to their associated drive units; and (c) an angular sensor configured to detect the angular position and orientation of the shaft within the housing.

The crusher may be a cone crusher or a gyratory crusher.

According to a second aspect of the disclosure, there is provided a coupling for use in a crusher as described in the first aspect.

According to a third aspect of the disclosure, there is provided a tie rod for use in a crusher as described in the first aspect.

According to a fourth aspect of the disclosure, there is provided a hydraulic cylinder for use in a crusher as described in the first aspect.

According to a fifth aspect of the disclosure, there is provided a method of operating a crusher having a housing supporting an outer crushing shell and further having a crushing head located within the housing and being mounted on a shaft, the crushing head supporting an inner crushing shell that cooperates with the outer crushing shell to form a crushing gap therebetween, the method comprising the step of providing a coupling mounted on the shaft, whereby the coupling is able to rotate around the shaft, and joining a drive mechanism comprising at least three drive units to the coupling for generating movement of the inner crushing shell relative to the outer crushing shell.

The method may include the step of having the drive mechanism generating movement of the crushing head by imparting only a pulling force on the shaft. The method may include the step of selectively activating each of the drive units to generate movement of the crushing head relative to the housing.

Each of the drive units may be one of a hydraulic cylinder, a linear motor and a solenoid. When the drive units are hydraulic cylinders, the method may include the step of utilising a force exerted by a cylinder that is selectively activated to exhaust hydraulic fluid from other cylinders. The method may include the step of replacing a portion of hydraulic fluid used in the hydraulic drive mechanism when each of the cylinders is selectively activated. Such replacement of the portion of the hydraulic fluid may assist in regulating a temperature of the hydraulic fluid. The crushing head may be supported on a bearing, wherein the method includes the step of ejecting the portion of hydraulic fluid between the bearing and the crushing head.

The method may include the step of adjusting a pressure of hydraulic fluid used in the hydraulic drive mechanism to thereby select a desired crushing pressure to be exerted by the crushing head.

Each cylinder may include a piston reciprocally movable between an inner position proximal to the shaft and an outer position distal to the shaft, wherein the method further includes the steps of selectively activating and deactivating each of the cylinders to generate orbital or gyratory movement of the crushing head relative to the outer crushing shell, wherein each cylinder is activated while its piston is moving from its inner position towards its outer position and each cylinder is deactivated while its piston is moving from its outer position towards its inner position.

In the method, the step of activating each of the cylinders may include injecting hydraulic fluid into each respective cylinder thereby to apply movement force to its piston and the step of deactivating each of the cylinders may include permitting the passive movement of each piston to exhaust hydraulic fluid from its cylinder. The method may include the steps of activating each cylinder after its piston moves past its inner dead centre position and deactivating each cylinder after its piston moves past its outer dead centre position.

The method may include the steps of providing a processing unit having a memory module and of storing a minimum inner dead centre position for each piston and a maximum outer dead centre position for each piston in the memory module.

The method may include the step of programming the processing unit with a desired operational crushing pressure to be exerted by the crushing head, whereby during use the processing unit is arranged to adjust the pressure of hydraulic fluid injected into the cylinders to obtain the desired operational crushing pressure.

Alternatively, the method may include the step of programming the processing unit with a desired operational displacement of the crushing head, whereby during use the processing unit is arranged to adjust the volume of hydraulic fluid injected into the cylinders to obtain the desired operational displacement. In such case the volume of hydraulic fluid injected into the cylinders may be selectively increased to increase the extent of movement of the crushing head and decreased to decrease the extent of movement of the crushing head.

Alternatively, the method may include the step of programming the processing unit with a desired operational crushing pressure to be exerted by the crushing head,.

One or more position sensors may be associated with the drive units, wherein the method may include the step of determining the operative position of the crushing head within the housing.

The drive units may be spaced substantially equidistantly around the shaft. The method may include the step of activating the drive units consecutively in a desired order around the shaft. The drive mechanism may include at least five drive units and, in some embodiments, the method may include the step of concurrently activating at least two of the drive units.

The method may be used for operating a cone crusher or a gyratory crusher.

The above and other features will become more apparent from the following description and with reference to the accompanying schematic drawings. In the drawings, which are given for purpose of illustration only and are not intended to be in any way limiting, there is shown in:.

The present disclosure relates to a crusher that is used for crushing solid material, such as ore, and more particularly to a drive mechanism for such a crusher. The crusher will typically be a cone crusher or a gyratory crusher.

Referring to <FIG> and <FIG> of the drawings there is shown a first embodiment of a cone crusher <NUM> which is used, for example, for crushing coarse ore into finer particle size ore. The cone crusher <NUM> comprises a housing <NUM> defining a chamber <NUM> for containing the various operational parts of the cone crusher <NUM>. The housing <NUM> includes a lower bowl body <NUM> that is closed at its upper end by a removable lid <NUM>. A frusto-conical opening <NUM> extends through the lid <NUM>, through which opening <NUM> the feed ore can pass into the chamber <NUM> during use.

A frusto-conical outer crushing shell <NUM> (also known in the art as a bowl liner) is supported by the housing <NUM> so as to line the opening <NUM>.

A crushing head <NUM> is located inside the chamber <NUM> with the crushing head <NUM> being mounted on a shaft <NUM>. The crushing head <NUM> is conical in shape and extends at least partially into and/or through the opening <NUM>. The crushing head <NUM> supports an inner crushing shell <NUM> (also known in the art as a mantle) that is secured in place by a cap <NUM> being joined to the shaft <NUM>. Alternatively, the inner crushing shell <NUM> can be secured to the crushing head <NUM> by any other conventional methods. Yet further, in some embodiments the inner crushing shell <NUM> can be integrally formed as part of the crushing head <NUM>. The space between the outer crushing shell <NUM> and the inner crushing shell <NUM> defines a crushing gap <NUM>. Due to the outer crushing shell <NUM> having a narrower cone angle than that of the inner crushing shell <NUM>, the crushing gap <NUM> is wider near the outer side of the lid <NUM> and narrower near the inner side of the lid <NUM>.

Both the outer crushing shell <NUM> and the inner crushing shell <NUM> are wear items and are configured to be replaced when needed. Although not shown in the drawings, the position of lid <NUM> and/or the crushing head <NUM> are able to be adjusted, whereby lid <NUM> can be moved closer to or further from crushing head <NUM> to provide one method of adjusting the size of the crushing gap <NUM>.

The crushing head <NUM> is movably supported within the chamber <NUM> on a spherical support or bearing <NUM> which itself is mounted on an inner frame <NUM>. The bearing <NUM> can be made of a single bearing pad or the bearing <NUM> can comprise multiple bearing pads. In the latter case, the bearing pads can be positioned directly adjacent to each other or spaced slightly apart from each other.

The inner frame <NUM> is substantially cylindrical and stands on a floor <NUM> of the bowl body <NUM>. Inner frame <NUM> has an outwardly projecting flange <NUM> located approximately midway along its height, which is arranged to rest on and be joined to a collar <NUM> projecting inwardly from a side wall <NUM> of the bowl body <NUM> to fix the inner frame <NUM> to the bowl body <NUM>.

Inner frame <NUM> supports a drive mechanism <NUM> that is joined to shaft <NUM> for causing gyratory movement of the crushing head <NUM>. During use this movement is normally of either an orbital or a gyratory nature. The drive mechanism <NUM> comprises a number of drive units that, in the exemplary embodiment, are hydraulic cylinders <NUM> and pistons <NUM> being spaced around the shaft <NUM>. It is envisaged that the drive mechanism <NUM> will generally have between three and ten cylinders <NUM>, however, it may be that additional cylinders need to be provided to operate very large cone crushers <NUM>. In <FIG> of the drawings the cone crusher <NUM> is shown having six cylinders <NUM> but it is generally expected that five cylinders will suffice for most situations and in <FIG> the hydraulic circuit only shows five cylinders. In <FIG>, the cylinders <NUM> are shown being integrally formed with inner frame <NUM>. However, it should be appreciated that in other embodiments the cylinders <NUM> can be separately formed and subsequently joined to the inner frame <NUM> or to the housing <NUM> (an example of the latter will be described below with reference to <FIG>).

Each cylinder <NUM> houses a piston head <NUM> from which its piston rod <NUM> extends through an orifice <NUM> in the inner frame <NUM> towards the shaft <NUM>. The pistons <NUM> are reciprocally movable within the cylinders <NUM> between an inner position proximal to the shaft <NUM> and an outer position distal to the shaft <NUM>. Sealing rings <NUM> are respectively provided surrounding the piston head <NUM> and the piston rod <NUM> so that a sealed cylinder chamber <NUM> is formed on the side of the piston head <NUM> closest to the shaft <NUM>. The sealing rings <NUM> prevent hydraulic fluid from escaping from the cylinder chamber <NUM>, either out past the piston head <NUM> or past the piston rod <NUM>. At its terminal end the piston rod <NUM> is joined to one end of a tie rod <NUM>. The opposed end of the tie rod <NUM> is joined to a coupling <NUM> mounted on the shaft <NUM>.

The exemplary embodiment shows a simplified configuration of the tie rod <NUM> and coupling <NUM>, wherein the tie rod <NUM> is a double ball headed tie rod (e.g. shaped like a dumbbell) that has each of its balls being held in respective spherical recesses in the piston rod <NUM> and in the coupling <NUM>. The opposed spherical heads of the tie rod <NUM> enable the tie rod <NUM> to pivot through a limited extent relative to both the piston rod <NUM> and the coupling <NUM> during operative reciprocal movement of their pistons <NUM> within their cylinders <NUM>.

In alternative more complex configurations, the tie rods <NUM> can be joined to the piston rod <NUM> and the coupling <NUM> using any one of the known universal joints or constant-velocity joints, such as a Tracta joint, a Rzeppa joint, a Weiss joint, a Cardan joint or double Cardan joint, a Thompson coupling or a Malpezzi joint. In some instances, the tie rods <NUM> can be joined directly to their piston heads <NUM>.

It will be appreciated that the above arrangement of the pistons <NUM> and tie rods <NUM> will, during use, result in the pistons <NUM> imparting a pulling force on the tie rods <NUM> to move the shaft <NUM> towards the respective cylinders <NUM>. Nevertheless, the scope of this disclosure also considers the possibility of changing the above arrangement so that a converse pushing force can be imparted on the tie rods <NUM> to move the shaft <NUM> towards the respective cylinders <NUM>. This can be achieved by simply locating the sealed cylinder chamber <NUM> on the side of the piston head <NUM> furthest from the shaft <NUM>. However, the application of a pulling force is preferred over a pushing force as it reduces potential damage to the tie rods <NUM>. For example, a pushing force could result in buckling or bending in the tie rods <NUM>. Also, in some instances, a pushing force can tend to rotate the coupling <NUM> around the shaft <NUM>, which would dissipate some of the energy from the hydraulic drive mechanism <NUM> and result in a reduced crushing force being applied by the crushing head <NUM>.

In some embodiments the shaft <NUM> carries a counterweight <NUM> being arranged to offset the mass of the crushing head <NUM>. The counterweight <NUM> can be connected to the shaft <NUM> so that it rotates together therewith and, accordingly, with the crushing head <NUM>. Alternatively, the counterweight <NUM> can be rotatable on the shaft <NUM> so that it can rotate independently from the crushing head <NUM>.

A hydraulic fluid line <NUM> leads from a reservoir tank (not shown) to each cylinder chamber <NUM> whereby hydraulic fluid can be pumped into or exhausted from the cylinder chamber <NUM>, thereby to cause movement of the piston <NUM>.

Referring now to <FIG>, there is shown an embodiment of a hydraulic circuit <NUM> for operating the cone crusher <NUM> wherein the drive mechanism <NUM> is configured to achieve approximately a 40kN pulling force on the tie rods <NUM>. A skilled addressee will be able to adapt this hydraulic circuit to provide up to 150kN pulling force. A hydraulic pump <NUM> driven by motor <NUM> supplies the hydraulic fluid into the hydraulic circuit <NUM> under a pressure of about <NUM> bar. It is expected that there will be certain pressure losses through the various valves in the hydraulic circuit <NUM> depending on the types of valves selected, resulting in the pressure in the cylinders <NUM> being approximately <NUM> bar.

The output of pump <NUM> is led via fluid line <NUM> through a filter <NUM>, whereafter the fluid line <NUM> is divided through manifold line <NUM> into the requisite number of parallel banks of control valves <NUM>. It should be understood that each cylinder <NUM> has a unique control valve <NUM> associated therewith, i.e. when the drive mechanism <NUM> includes six cylinders <NUM> (as shown in <FIG> and <FIG>) then there will be six control valves <NUM>, whereas when the drive mechanism <NUM> includes five cylinders <NUM> then there will be five control valves <NUM> (as shown in <FIG>). In other embodiments, each cylinder <NUM> may be operated using two control valves.

Each control valve <NUM> is a three-position pilot operated proportional directional valve configured to control flow of the hydraulic fluid into its associated cylinder chamber <NUM>. Valve spool of control valve <NUM> is biased by spring <NUM> to its first (left) default position to close off pump port P so that fluid in the cylinder chamber <NUM> is able to be exhausted through cylinder port A and tank port T via fluid line <NUM> leading from the cylinder chamber <NUM> and fluid line <NUM> leading to the reservoir tank. In the second (central) position of control valve <NUM> all its ports A, P and T are open so that fluid pressure is equalised across the control valve <NUM>. In the third (right) position of control valve <NUM> tank port T is closed and pump port P is opened to allow fluid flow through cylinder port A and fluid line <NUM> into cylinder chamber <NUM>. Movement of the valve spool is controlled by a solenoid operated pilot head <NUM> that, when suitably pressurised, overcomes the biasing force of spring <NUM>. It should be understood that the middle and right positions are essentially the same in that the control valve <NUM> is a proportional valve meaning that it is not just open or shut; the middle and right positions describe the control valve <NUM> as being partially open to the degree of bias from its fully middle position to its fully right position.

Each cylinder <NUM> is further provided with a bleed fluid line <NUM> (not shown in <FIG> and <FIG>), which is configured to bleed off a small portion volume of the hydraulic fluid from the cylinder chamber <NUM> that is exhausted to the reservoir tank. This bleeding of the hydraulic fluid functions to change out a small percentage volume of the hydraulic fluid to ensure that an equivalent volume of fresh hydraulic fluid is drawn from the reservoir tank into the hydraulic circuit <NUM>. In some embodiments it is expected that the hydraulic fluid will experience a temperature increase during operation due to the high pressures being exerted thereon. Changing out the hydraulic fluid will assist in regulating the hydraulic fluid temperature and keeping it more constant because the fresh hydraulic fluid drawn from the reservoir tank will be at a cooler temperature than the hydraulic fluid withdrawn from the cylinder chamber <NUM>. In some embodiments the bleed fluid line <NUM> can be provided with a valve to close of the line to prevent flow of hydraulic fluid. However, in the exemplary embodiment the bleed fluid line <NUM> has no valve and hydraulic fluid can flow at all times, wherein the volume of be hydraulic fluid flowing through bleed fluid line <NUM> is dependent on the cross-sectional size of the bleed fluid line <NUM> as well as the pressure of hydraulic fluid within the cylinder chamber <NUM>. Thus, in the present example, more hydraulic fluid will flow through the bleed fluid line <NUM> whilst its associated cylinder <NUM> is being activated (i.e. with its control valve <NUM> in its middle or right positions), whilst less hydraulic fluid will flow through the bleed fluid line <NUM> whilst its associated cylinder <NUM> is being exhausted (i.e. with its control valve <NUM> in its left position. The bleed fluid line <NUM> can optionally include a one-way valve to prevent hydraulic fluid from flowing from the bleed fluid line <NUM> into the cylinder chamber <NUM>.

The hydraulic circuit <NUM> further includes additional hydraulic components being generally indicated by arrow <NUM> (such as valves, accumulators and pumps) that function to operate the respective pilot heads <NUM> of the control valves <NUM>.

<FIG> shows a second embodiment of a cone crusher <NUM> which includes substantially the same features as the cone crusher <NUM> of <FIG> and accordingly, similar parts will be indicated with the same reference numerals.

In the cone crusher <NUM> the crushing head <NUM> is movably supported within the chamber <NUM> on a spherical support or bearing <NUM> which is supported by the bowl body <NUM>. The bearing <NUM> includes a number of bearing pads <NUM> having openings therein to allow the injection of hydraulic fluid between the bearing <NUM> and the crushing head <NUM>. As will be later described, the hydraulic fluid is used to lubricate and lift the crushing head <NUM> up from the bearing <NUM> thereby to assist in reducing friction between these parts. The hydraulic fluid is fed to the bearing pads <NUM> via fluid line <NUM>. A peripheral seal <NUM> extends around the crushing head <NUM> to prevent leakage of the hydraulic fluid into a discharge area <NUM> of chamber <NUM> receiving the crushed ore that passes through the crushing gap <NUM>.

Further, in the cone crusher <NUM>, the hydraulic drive mechanism <NUM> is directly supported by the housing <NUM> on an outside thereof, i.e. outside the chamber <NUM>. Having the cylinders <NUM> mounted externally on the housing <NUM> allows easier access to the cylinders <NUM> in comparison to those of the first embodiment shown in <FIG>, for example in the event that maintenance is required. Additionally, it also eases the coupling of hydraulic pipes and conduits to the cylinder <NUM>. In this case the piston rods <NUM> and tie rods <NUM> extend from each cylinder <NUM> through passages <NUM> passing through the bowl body <NUM> towards the shaft <NUM>.

<FIG> further shows bleed fluid line <NUM> (being equivalent to the bleed fluid line <NUM> referenced in <FIG>) leading from the cylinder chamber <NUM> and extending through the bowl body <NUM> to join in flow communication with the fluid line <NUM>.

The cone crusher <NUM> has one bearing pad <NUM> being associated with each of the cylinders <NUM>, whereby in use the hydraulic fluid exiting the cylinder chamber <NUM> through bleed fluid line <NUM> is pumped to its associated bearing pad <NUM> and used for lifting the crushing head <NUM>. If needed, a pressure regulator can be provided in bleed fluid line <NUM> to reduce the pressure of the hydraulic fluid therein. In other embodiments each cylinder <NUM> may be associated with multiple bearing pads <NUM> with the bleed fluid line <NUM> arranged to disperse the hydraulic fluid between each of its associated bearing pads <NUM>. In some examples the bleed fluid line <NUM> can lead to a distribution manifold (not shown), wherein hydraulic fluid can be dispersed to any one or more of all the bearing pads <NUM> in the bearing <NUM> - in such case, one-way valves are provided between each of the cylinders <NUM> and the distribution manifold, the valves being configured to prevent hydraulic fluid flowing from the distribution manifold back to the cylinders <NUM>; this is to prevent hydraulic fluid flowing from the activated cylinder to other cylinders from which hydraulic fluid is being drained to the reservoir tank.

During operation, the hydraulic circuit <NUM> selectively activates and deactivates each of the cylinders <NUM> consecutively in order, i.e. neighbouring cylinders <NUM>, to cause the individual cylinders <NUM> of the drive mechanism <NUM> to cyclically pull their pistons <NUM> away from the shaft <NUM>. In so doing, the pistons <NUM> respectively cyclically pull the shaft <NUM> away from its centre axis towards the respective cylinders <NUM> and thereby cause the crushing head <NUM> to swivel in an orbital motion within the spherical bearing <NUM> to close the crushing gap <NUM> between the inner crushing shell <NUM> and the outer crushing shell <NUM>. Alternatively, the hydraulic circuit <NUM> may be adjusted to selectively activate and deactivate each of the cylinders <NUM> consecutively in a star or criss-cross order so that the pistons <NUM> respectively pull the shaft <NUM> away from its centre axis towards the respective cylinders <NUM> and thereby cause the crushing head <NUM> to move in a gyratory or erratic motion within the spherical bearing <NUM>.

When orbital motion is desired, each cylinder <NUM> is activated while its piston <NUM> is moving from its inner position towards its outer position and each cylinder <NUM> is deactivated while its piston is moving from its outer position towards its inner position. The step of activating each of the cylinders <NUM> is performed by injecting hydraulic fluid into each respective cylinder <NUM> thereby to apply movement force to its piston <NUM>. Conversely, the step of deactivating each of the cylinders <NUM> is performed by stopping such fluid injection and permitting the movement of each piston <NUM> to exhaust the hydraulic fluid from its cylinder <NUM>. Accordingly, each cylinder <NUM> is activated after its piston <NUM> moves past its inner dead centre position and is deactivated after its piston <NUM> moves past its outer dead centre position.

Feed ore is deposited through the opening <NUM> so that it falls into the crushing gap <NUM> where it is crushed between the inner crushing shell <NUM> and the outer crushing shell <NUM> and disintegrates into a finer particulate product which is then withdrawn from the cone crusher <NUM>, i.e. from the discharge area <NUM>, in a conventional manner.

The cone crusher <NUM> enables a varying crushing pressure to be applied by the crushing head <NUM> by controlling the pulling force applied to the shaft <NUM> by the pistons <NUM>, e.g. by changing the operating pressure of the hydraulic fluid pumped into the cylinder chambers <NUM>. In a similar manner, the cone crusher <NUM> also enables the size of the crushing gap <NUM> to be adjusted by controlling the distance that the shaft <NUM> is pulled towards the cylinders <NUM>, e.g. by changing the volume of the hydraulic fluid pumped into the cylinder chambers <NUM>. For example, in one configuration, moving the pistons <NUM> to their full extent through the cylinders <NUM> causes the crushing gap <NUM> to be closed and the inner crushing shell <NUM> will contact against the outer crushing shell <NUM>; whereas moving the pistons <NUM> to only halfway through the cylinders <NUM> causes the crushing gap <NUM> to remain open with the inner crushing shell <NUM> still being spaced apart from the outer crushing shell <NUM>. The size of the crushing gap <NUM> can also be adjusted in conventional manner by moving lid <NUM> closer to crushing head <NUM> (or vice versa).

The required crushing pressure may be calculated based on the material composition of the feed ore being introduced through the opening <NUM>. The crushing pressure may be increased for feed ore having a high density or hardness, whereas the crushing pressure may be reduced for a feed ore having a lower density or hardness.

The operation of the hydraulic circuit <NUM> is simplified in that the cylinders <NUM> are spaced from each other around the shaft <NUM>. In some examples the cylinders <NUM> can be spaced substantially equidistantly from each other around the shaft <NUM>, e.g. being radially spaced in some cases. In other examples the cylinders <NUM> can be spaced at specific selected distances from each other around the shaft <NUM>. Accordingly, it is not necessary for the hydraulic circuit <NUM> to actively pump the hydraulic fluid out of the cylinder chambers <NUM>. Rather, the pulling force exerted by an activated cylinder operates to exhaust hydraulic fluid from any of the other cylinders. This can be more clearly understood by referring to <FIG>, wherein when a first cylinder <NUM> (of which only its piston rod <NUM> is shown in <FIG>) is activated to pull on the shaft <NUM>, i.e. when its control valve <NUM> is switched to either its second (central) or third (right) position, the remaining cylinders <NUM>-<NUM> will have their control valves <NUM> switched into their first (left) positions so that the pulling operation of the first cylinder <NUM> will cause the hydraulic fluid to be exhausted from some of the remaining cylinders. It will be appreciated that in such case the cylinder <NUM> being furthest from or diametrically opposed to the first cylinder <NUM> will experience the greatest exhaust rate. This operation will be repeated cyclically as each of the cylinders <NUM> are activated in turn.

As mentioned above, as the hydraulic fluid is exhausted from the cylinder chambers <NUM>, the majority thereof will exit through the fluid line <NUM>, while a small portion thereof will be bled off through bleed fluid line <NUM>, which smaller portion is pumped to its associated bearing pad <NUM> and used for the lifting of the crushing head <NUM>.

In another example, a cylinder <NUM>. n whose piston <NUM>. n is fully retracted may have its piston <NUM>. n held in such fully retracted position until the operatively following cylinder <NUM>. n+<NUM> has its piston <NUM>. n+<NUM> reach its fully retracted position. For example, once piston <NUM> is fully retracted to its outer dead centre position within cylinder <NUM>, piston <NUM> is held remaining in such outer dead centre position until piston <NUM> reaches and is held in its outer dead centre position within cylinder <NUM>, whereafter piston <NUM> is released and piston <NUM> is held at its outer dead centre position until piston <NUM> is retracted and reaches its outer dead centre position.

The cone crusher <NUM> further includes a processing unit (not shown) used to control the hydraulic circuit <NUM>. In one embodiment, the processing unit is able to determine the positional status of the pistons <NUM> within their cylinders <NUM> and to thereby calculate the position of the crushing head <NUM> on or within the spherical bearing <NUM> by using a position algorithm. This will typically be done by attaching one or more position sensors to some of or all the cylinders <NUM> to detect the position of the piston heads <NUM> within their respective cylinders <NUM>. In another embodiment, the cone crusher <NUM> optionally further includes a positional sensing mechanism being configured to determine the operative position of the crushing head <NUM> on or within the spherical bearing <NUM>, alternatively doing so by detecting the angular position and orientation of the shaft <NUM> within the housing <NUM>. In one example, the positional sensing mechanism may include a proximity sensor being configured to detect the proximity of the tie rods <NUM> and/or the shaft <NUM> to their associated cylinders <NUM>. In another example, the positional sensing mechanism may include an angle sensor configured to detect the angular position of the shaft <NUM>. In yet a further example, the positional sensing mechanism may include a camera configured to perform image analysis to determine the position of the crushing head <NUM>.

The processing unit of the cone crusher <NUM> may be programmed to detect if there are any blockages in the crushing gap <NUM>. Such blockages would typically arise due to tramp material entering through the opening <NUM> and becoming lodged between the inner crushing shell <NUM> and the outer crushing shell <NUM>. The detection of such blockages can be made by comparing the actual position of the crushing head <NUM> determined by the position sensing mechanism with the expected position that the crushing head <NUM> should be in when certain of the control valves <NUM> are fully or partially open. If there is an offset between the actual position and the expected position, then the processing unit will determine that a blockage exists and the processing unit can then restrict the flow or pressure of the hydraulic fluid to prevent excessive damage to the inner crushing shell <NUM> and the outer crushing shell <NUM>. Such regulation of the hydraulic fluid flow or pressure will provide a form of active control. In another example, providing passive control, the hydraulic circuit <NUM> may include a pressure relief valve wherein the hydraulic fluid pressure is limited to a certain value, namely whereby the hydraulic fluid flowing towards the cylinders <NUM> is diverted through the pressure relief valve back to the reservoir tank to thereby avoid the pistons <NUM> pulling the shaft <NUM> to the preselected position.

The processing unit can be programmed with a desired operational crushing pressure to be exerted by the crushing head <NUM>, whereby during use the processing unit is arranged to adjust the pressure of hydraulic fluid injected into the hydraulic cylinders <NUM> to obtain the desired operational crushing pressure.

Alternatively, the processing unit can be programmed with a desired operational displacement of the crushing head <NUM>, whereby during use the processing unit is arranged to adjust the volume of hydraulic fluid injected into the cylinders <NUM> to obtain the desired operational displacement. In such case the volume of hydraulic fluid injected into the cylinders <NUM> may be increased to increase the orbital movement of the crushing head <NUM> and the volume of hydraulic fluid injected into the cylinders <NUM> may be decreased to decrease the extent of the orbital movement of the crushing head <NUM>.

In yet a further alternative, the processing unit can be programmed with both a desired operational crushing pressure to be exerted by the crushing head <NUM> and with a desired operational displacement of the crushing head <NUM>. In such case the processing unit will also be programmed with a selection hierarchy between the crushing pressure and the displacement, whereby during use the processing unit is arranged to adjust both the pressure and the volume of hydraulic fluid injected into the cylinders <NUM> until either the desired crushing pressure or the desired displacement is achieved.

<FIG> shows an embodiment of a gyratory crusher <NUM> which includes substantially the same features as the cone crusher <NUM>, <NUM> of <FIG> and <FIG> and accordingly, similar parts will be indicated with the same reference numerals. In the gyratory crusher <NUM> the frusto-conical housing <NUM> is inverted so that the opening <NUM> has its widest part is at the top and the narrowest part at the bottom. The lid <NUM> rests on the housing <NUM> and is arranged to provide a fulcrum for the shaft <NUM> at pivot <NUM>. The shaft <NUM> has a spherically curved base that is supported on spherical bearing <NUM>. In use, the drive mechanism <NUM> pulls on shaft <NUM> so that crushing head <NUM> gyrates on bearing <NUM> around pivot <NUM> and crushes ore between the outer crushing shell <NUM> and the inner crushing shell <NUM>. Bearing <NUM> is mounted on an adjustment piston <NUM> that can be raised or lowered in a conventional manner to thereby raise or lower shaft <NUM> and crushing head <NUM> within the housing <NUM> to adjust the operational width of the crushing gap <NUM>. The further operation of the drive mechanism <NUM> will be the same as described above in relation to <FIG>.

It will be appreciated by persons skilled in the art that numerous variations and/or modifications may be made to the crusher as shown in the specific embodiments without departing from the scope of the disclosure as broadly described. The present embodiments are, therefore, to be considered in all respects as illustrative and not restrictive.

For example, the tie rods <NUM> can be provided in any other form that will allow the piston rods <NUM> to be pivotally joined to the coupling <NUM>. In this regard the tie rods <NUM> can be hinge connected to both the piston rods <NUM> and the coupling <NUM>. Alternatively, the tie rods can have end fittings in the form of ball joints as are found on link arms of a three-point hitch for being mounted on a pin.

Furthermore, it should be understood that the hydraulic cylinders may be substituted by suitable alternative drive units, for example whereby each of the drive units is a suitable mechanical or electric drive units such as a linear motor or solenoid. In such case each drive unit will have an actuator being joined to the tie rods <NUM>.

Claim 1:
A crusher for crushing material into finer particulates, the crusher (<NUM>) comprising a housing (<NUM>) supporting an outer crushing shell (<NUM>); a crushing head (<NUM>) located within the housing and being mounted on a shaft (<NUM>), the crushing head supporting an inner crushing shell (<NUM>) that cooperates with the outer crushing shell to form a crushing gap (<NUM>) therebetween, characterised thereby that
a coupling (<NUM>) is mounted on the shaft (<NUM>), whereby the coupling (<NUM>) is able to rotate around the shaft (<NUM>), and
a drive mechanism (<NUM>), comprising at least three drive units (<NUM>, <NUM>), is joined to the coupling (<NUM>) via a tie rod and is configured to generate movement of the inner crushing shell (<NUM>) relative to the outer crushing shell (<NUM>).