Patent Description:
Gyratory crushers are used for crushing ore, mineral and rock material to smaller sizes. Typically, the crusher comprises a crushing head mounted upon an elongate main shaft. A first crushing shell (typically referred to as a mantle) is mounted on the crushing head and a second crushing shell (typically referred to as a concave) is mounted on a frame such that the first and second crushing shells define together a crushing chamber through which the material to be crushed is passed. A driving device positioned at a lower region of the main shaft is configured to rotate an eccentric assembly positioned about the shaft, so as to cause the crushing head to perform a gyratory pendulum movement and crush the material introduced in the crushing chamber.

The inner crushing shell and the outer crushing shell become worn and require replacement at regular intervals. A variety of different assemblies have been proposed for mounting the inner crushing shell at the main shaft in an attempt to both provide a reliable lock and convenient mounting and dismounting of the mantle, this is typically referred to as a head nut. Conventional arrangements are still disadvantageous as it is typically required to use a sledge hammer or a hydraulic hammer for both tightening and loosening. It is therefore important to provide a reliable retaining mechanism being able to stand the crushing forces as well as safely mount and dismount the retaining mechanism at the crusher frame and the crushing head. By using a hammer the threads of the retaining mechanism normally gets damaged due to tilting or due to excessive forces being used, which leads to extra costs since components get broken. It is a dangerous work leading to personal often getting injured. From document <CIT>A there is known a crushing mantle assembly comprising a mantle having a flange for relieving the thrust or expansion of the metal of the mantle caused to flow by the crushing impacts during operation. A known retainer assembly to releasably secure a mantle at a head centre of a gyratory crusher is described in <CIT>. <CIT> relates to a known a method and device for mounting a crushing cone on the cone carrier of a cone crusher. A known method for assembling lining plates of a multi-cylinder cone crusher is disclosed in <CIT>. In <CIT> there is disclosed a rotary crusher, the crushing cone of which is provided with a crushing cone chuck, which is clamped against the conical surface of the crushing cone via a nut screwed onto the crushing cone pin. Installed between the crushing cone pin and the clamping nut is a threaded ring which is detachably connected to the crushing cone pin and a hydraulic pressure device acting between the threaded ring and the crushing cone chuck.

There is a need to not damage the threads and to not use excessive forces when mounting and dismantling the crusher as when hammering using a sledge hammer or a rammer bar. Further, there is a need for the personal to be able to safely mount and dismount the crusher.

Thus, what is required is a retainer assembly and a tool for mounting and dismounting the shells at the crusher that addresses the above problems.

It is an object of the present invention to provide a tool that in a secure manner for personal is used to tighten and secure a retainer assembly at a crusher, while the tool also is used to securely loosen and remove the retainer assembly from the crusher. Further there is an objective to rely on a tool working in equilibrium when applying force for tightening/loosening such that there is no risk of the head nut tilting. This also leads to prolonged lifetime of the head nut, such that there will be less costs due to fewer times that replacement is needed.

The objectives are achieved by providing a tool for a retainer assembly with a two-point tightening by actuators that are able to apply a predefined force when mounting and dismounting.

According to a first aspect of the present invention there is provided a tool for a retainer assembly of a gyratory crusher, the tool being intended to be arranged around a shaft of the crusher on top of a retainer assembly securing a crushing shell, and wherein the tool is characterized by comprising: a first plate being arranged on top of a second plate and wherein the plates being able to rotate in relation to each other, and wherein the plates comprising a centered through hole coinciding with each other; the first plate having a smaller outer periphery than the second plate; a first and a second actuator mounted on the second plate at the periphery on opposite sides; a first and a second lever arm mounted on the first plate and mounted in connection to the first and the second actuator, respectively, and wherein the lever arms comprising gripping surfaces intended to be arranged around the shaft; a first and a second movable spigot mounted on the first plate in connection to the first and the second lever arm, respectively; and pins mounted on the lower side of the second plate in order for the tool being adapted to fit with the retainer assembly. This is a robust tool that makes the personal being able to use it for mounting/dismounting the retainer assembly in a safe way.

Preferably the tool comprising blocks mounted on the lower side of the second plate, evenly distributed on a circle, and to which blocks the pins being mounted. This achieves the required spacing axially for fitting of the pins.

Optionally the tool comprising two pins mounted on two different blocks, respectively. This gives a good balance when mounting the tool.

Optionally the two pins being mounted on two oppositely arranged blocks, respectively. This gives an appropriate distance between the pins so they are connected to the assembly in order to achieve a good anchoring of the pins.

Preferably the tool comprising four pins mounted on four blocks, respectively. Thereby a very firm connection to the retainer assembly is achieved.

Preferably the gripping surfaces of the lever arms comprising flexible cushions and the number of cushions being at least one. This gives good support and a good grip against the shaft with adequate friction.

Preferably the gripping surfaces of the lever arms comprising flexible cushions and the number of cushions being six on each lever arm. This is advantageous in order for the tool to have an optimal grip around the shaft.

According to a second aspect of the present invention there is provided a retainer assembly for securing a crushing shell to a crusher, by means of using the tool according to the first aspect of the present invention, wherein the retainer assembly being adapted for engagement with the tool to be secured to and/or removed from the crusher and comprising: a head nut having a first surface to be radially inward facing towards the shaft of the crusher and a second surface to be radially outward facing towards an axial upper region of the shell; a support ring arranged between the head nut and the shaft; wherein the head nut comprising holes on a top side, the holes being arranged and adapted to fit with the pins on the lower side of the second plate of the tool.

Optionally the holes being evenly distributed around the perimeter of the top side of the head nut. In order to have even distribution of the connection and transmittal of forces when the tool is active.

Preferably the holes being formed in protrusions protruding in radial direction of the head nut and wherein each protrusion comprising one hole. This gives the retainer assembly a slim design.

Optionally the number of holes being four. Thereby a balanced connection with the tool is achieved.

Preferably the retainer assembly comprising a wear plate securely arranged adjacent on top of the head nut. This gives good protection of the crusher such that the retainer assembly is not prone to wear.

Optionally the wear plate being securely arranged onto the head nut by means of threaded joints, and wherein the wear plate further comprising conical nuts arranged on top of the joints and flush with the upper side of the wear plate. Thereby the joints are covered and do not get damaged.

According to a third aspect of the present invention there is provided a method for using a tool according to a first aspect of the present invention, in order to fasten a retainer assembly at a gyratory crushing shell, wherein the method comprising the following steps: arranging the tool around the shaft of the crusher on top of the retainer assembly, with the pins mounted on the lower side of the tool fitting into the retainer assembly holes and with the gripping surfaces of the lever arms arranged around the shaft; mounting the first and second spigot on the first plate in connection to the first and the second lever arm, respectively, wherein the spigot is mounted on the side of the lever arm facing away from the actuator; retracting initially first and a second actuator, wherein the second plate being rotated; retracting continously until full retraction of first and second actuator, wherein the first plate being rotated; and reaching maximum capacity of actuators, wherein the retainer assembly being fastened. This is a secure method of tightly fastening the retainer assembly.

Optionally the method comprising the following further steps: removing the tool; arranging the wear plate around the shaft of the crusher on top of the retainer assembly; and securely arranging the wear plate to the retainer assembly.

A specific implementation of the present invention will now be described by way of example only and with reference to the following drawings in which:.

<FIG> discloses a gyratory crusher mantel having a tool <NUM> mounted in connection to a retainer assembly for securing an inner crushing shell <NUM> on a vertical shaft <NUM> of a gyratory crusher. The retainer assembly aims to secure an inner crushing shell <NUM> on a conical shaped head that is arranged on a vertical shaft <NUM>. The shaft is rotatably driven by suitable drives and gears (not shown) to precess within the crusher to displace the inner crushing shell <NUM> radially relative to an outer crushing shell (not shown). The retainer assembly need to be approriate both for attachment and detachment of the crusher, and also be able to resist loading forces transmitted through the crusher and the retainer assembly during use.

The tool <NUM> comprises two lever arms <NUM> arranged on opposite sides of the shaft <NUM>. The lever arms have gripping surfaces comprising cushions <NUM> being arranged on a bow shaped part of the lever arm in order to achieve a slim and firm fit around the shaft. The cushions are arranged on a part of the lever arm having the shape of a segment of a ring. The number of cushions being disclosed is a total of six, with three on each end of the segment. The number of cushions could also be a total of four, with two on each end of the segment, or a total of two, with one on each end of the segment. Possibly the number of cushions could also be higher such as a total of eight, with four on each end of the segment, or even a higher number. A further alternative embodiment is to have as gripping surface one large cushion covering the segment from one end to the other on the side facing towards the shaft. The gripping surfaces are made of rubber or any other type of flexible material.

<FIG> discloses a first embodiment of the tool <NUM> and the head nut <NUM> of the retainer assembly mounted on the shell around the shaft <NUM> seen in a perspective view from below. On the lower side <NUM> of the tool <NUM> blocks <NUM> are mounted on an imaginary circle. The number of blocks can be two or four or more. Alternatively it could also be one single continuous circular block. Two pins <NUM> are mounted oppositely to each other on the blocks. The pins <NUM> fit into holes <NUM> located in the head nut <NUM> at protrusions <NUM>. The protrusions are radially extensions, preferably four evenly distributed around the perimeter.

<FIG> discloses a second embodiment of the tool <NUM> and the head nut <NUM> of the retainer assembly mounted on the shell seen in a perspective view from below. In this embodiment the number of pins <NUM> mounted on blocks <NUM> is four. They are evenly distributed around the imaginary circle in order to fit into holes <NUM> of the head nut <NUM>. Also in this embodiment the number of blocks could be just one continuous circular ringshaped block to which the four pins are mounted. The number of pins <NUM> can be two, three, four or even more.

The blocks <NUM> as shown in the figures are rectangular such that the longitudinal direction of two of the blocks are parallel to the longitudinal direction of the first and second actuator <NUM>, respectively and the other two blocks <NUM> have a longitudinal direction being transversal to the longitudinal direction of the actuators. The blocks can be of any other shape than rectangular.

<FIG> disclose the tool <NUM> mounted around the shaft <NUM> of a gyratory crusher before tightening of the retainer assembly. <FIG> is a view of the tool seen from above. The tool <NUM> as disclosed in the figures has the shape of a truncated cylinder with an outer anullar edge <NUM> having a specific height and a lower outer circular plate <NUM> having an outer perimeter coinciding with the perimeter of the annular edge <NUM> and being connected to each other. The tool <NUM> can also have a different outer shape than circular, such as a hexagon or an octagon. The lower plate <NUM> comprises a centered through hole that is to be arranged around the shaft <NUM> of the crusher. An upper inner circular plate <NUM> has an outer perimeter being smaller than the lower circular plate <NUM>, and wherein the upper plate <NUM> comprises a centered through hole coinciding with the centered through hole of the lower plate <NUM>. Further the tool comprises a first and a second hydraulic actuator <NUM> mounted on the lower outer plate <NUM> at the periphery on opposite sides, such that the actuators (cylinders) are arranged to move in through holes of the annular edge <NUM>. The actuators can be electrically or hydraulically actuated. The number of actuators, lever arms and spigots can also be higher than two.

The first and a second lever arm <NUM> having a shape similar to a combination of the shape of the letters T and Y, such that the single leg being the base (lower part) of T/Y is rotatably connected to the first and the second actuator <NUM>, respectively. The opposite end of the lever arm <NUM> branching out into two legs (the bow shaped part comprising the cushions <NUM>) are to be arranged around the shaft <NUM> such that the two legs compose a segment of a circle. The part of the lever arms <NUM> comprising the two legs (upper part of T/Y) is rotatably connected to the upper inner plate <NUM>.

<FIG> disclose the tool <NUM> mounted around the shaft <NUM> of a gyratory crusher when tightening of the retainer assembly begins. <FIG> is a view of the tool seen from above. The lever arms <NUM> will move when the actuators <NUM> are moving. The actuators <NUM> are fixedly arranged to the wall of the tool, at the annular edge <NUM>. So, when retracting the actuators <NUM> the outer plate <NUM> will move in the clockwise direction, as indicated by the arrow. The first and the second spigot <NUM> are mounted in connection to the first and the second lever arms <NUM>, respectively, on the side of the lever arm facing away from the actuator <NUM>. At this sequence of tightening of the head nut the bow shaped part of the lever arms being closest to the actuator will make contact with the shaft.

<FIG> disclose the tool <NUM> mounted around the shaft <NUM> of a gyratory crusher when the tool is taking new grip after full retraction of actuators. The clamping force at the shaft being loosened when the cylinders are compressed.

<FIG> disclose the tool <NUM> mounted around the shaft <NUM> of a gyratory crusher when the tool is taking a new grip in a tightening sequence of the retainer assembly. At this sequence of tightening retraction of the actuators will make the lever arms <NUM> put pressure on the spigots <NUM> and the inner plate <NUM> rotating in clockwise direction, as indicated by the arrows. The actuators <NUM> will be extending in order for the gripping surfaces of the lever arms <NUM> to take a new grip. The retracting and extending of the actuators will be repeated until the retainer assembly is fastened.

<FIG> discloses the tool <NUM> mounted around the shaft <NUM> of a gyratory crusher before loosening of the retainer assembly. The spigots <NUM> are moved to the same side of the lever arms <NUM> as the actuators <NUM>. The loosening of the retainer assembly can then start by using the extending direction of the actuators (cylinders). The spigots can be any kind of stopping element such as a hook, arm or a pin.

<FIG> discloses the tool <NUM> mounted around the shaft <NUM> on top of the shell. The blocks <NUM> are resting against the retainer assembly <NUM>. The retainer assembly <NUM> comprising a support ring <NUM> and a head nut <NUM>. The support ring <NUM> being arranged between the head nut <NUM> and the shaft <NUM>. The pins <NUM> of the tool are arranged in the holes (<NUM>) of the head nut.

<FIG> discloses the retainer assembly <NUM> after tigthening, so the tool <NUM> having been removed. A wear plate <NUM> is arranged on top of the retainer assembly <NUM> around the shaft <NUM> on top of the shell <NUM>.

Claim 1:
A tool (<NUM>) for a retainer assembly (<NUM>) of a gyratory crusher, the tool (<NUM>) being intended to be arranged around a shaft (<NUM>) of the crusher on top of a retainer assembly (<NUM>) securing a crushing shell (<NUM>), characterzed in that the tool (<NUM>) comprising:
a first plate (<NUM>) being arranged on top of a second plate (<NUM>) and wherein the plates being able to rotate in relation to each other, and wherein the plates (<NUM>, <NUM>) comprising a centered through hole coinciding with each other;
the first plate (<NUM>) having a smaller outer periphery than the second plate (<NUM>);
a first and a second actuator (<NUM>) mounted on the second plate (<NUM>) at the periphery on opposite sides;
a first and a second lever arm (<NUM>) mounted on the first plate (<NUM>) and mounted in connection to the first and the second actuator (<NUM>), respectively, and wherein the lever arms (<NUM>) comprising gripping surfaces intended to be arranged around the shaft (<NUM>);
a first and a second movable spigot (<NUM>) mounted on the first plate (<NUM>) in connection to the first and the second lever arm (<NUM>), respectively; and
pins (<NUM>) mounted on the lower side (<NUM>) of the second plate (<NUM>) in order for the tool (<NUM>) being adapted to fit with the retainer assembly (<NUM>).