Patent Description:
Gyratory type crushers are used in the mining industry for reducing ore to a predetermined size for further processing. These style of crushers have taken over most large hard-ore and mineral-crushing applications which has made them an integral part of the mining industry. Typically, a gyratory crusher includes a stationary conical bowl which opens upwardly and has an annular opening in its top to receive feed material. A conical pestle, opening downwardly, is disposed within the center of the bowl. The pestle is eccentrically oscillated for gyratory crushing movement with respect to the bowl. The conical angles of the pestle and bowl are such that the width of the passage decreases towards the bottom of the working faces and may be adjusted to define the smallest diameter of product ore. The oscillatory motion causes impact with the pestle and bowl, as a piece of ore is caught between the working faces of the bowl and pestle. Furthermore, each bowl and pestle includes a liner assembly replaceably mounted on the working faces, these liners define the actual crushing surface.

The liner on the pestle, called a mantle, is fitted around the outside of a mainshaft. The mantle provides a replaceable wearing surface. A threaded section on the mainshaft (or a threaded bearing sleeve fit over the mainshaft) is provided for receiving a headnut. The headnut forces the mantle downward onto the tapered portion of the mainshaft, and is forceably tightened against the top of the mantle. Tightening of the headnut prevents relative rotational movement between the headnut and the mantle. When the crusher is put into operation, the large forces involved in crushing stone cause a differential rotational movement between the mainshaft and the mantle. The headnut on the threaded section of the mainshaft is also caused to rotate relative to the shaft, in a direction which acts to further tighten the headnut onto the mantle. Thus, the rotational movement of the headnut relative to the mainshaft causes a large force to be transmitted in a downward direction from the headnut so as to forceably wedge the mantle onto the tapered portion of the mainshaft, securing the mantle to the mainshaft. The force also causes the bottom surface of the headnut to be pressed tightly against the top surface of the mantle such that the frictional force between the headnut and the mantle is quite large.

The frictional force between the headnut and the mantle makes it difficult to loosen the headnut by turning. Additionally, during operation of the crusher, the crushing surface of the mantle is subjected to a hammering action by repeated impact of the rock or other material being crushed. This hammering action causes the working surface of the mantle to expand by cold working. The expansion of the mantle works to increase the fictional force between the headnut and the mantle. The cumulative effect of the tremendous frictional force between the headnut and the mantle is that it becomes impossible to loosen the headnut by turning it.

It is, however, necessary to remove the headnut when the mantle become worn and needs replacing. Since it is not practical to loosen the headnut by turning, it must be cut from the threaded section of the mainshaft. Removing the headnut in this manner damages the headnut beyond repair so that it cannot be used again. The threaded section of the mainshaft (or bearing sleeve) is also easily damaged when removing the headnut in this fashion, such that the threaded mainshaft or bearing sleeve must be repaired, or possibly replaced.

A solution to this problem in the prior art is to provide a burning ring between the mantle and the headnut. The burning ring is adapted so as to engage to the upper surface of the mantle and the lower surface of the headnut. When the mantle is being replaced, the burning ring is cut with a cutting torch, relieving the frictional forces bearing on the headnut. The threaded portion of the headnut may then be unscrewed from the shaft and the mantle can be removed.

As an example of the prior art, <CIT> discloses a hydraulic mantle system for a gyratory rock crusher which includes a main shaft, an annular nut, an annular hydraulic piston and an annular mantle. The main shaft has a flange and external threads adjacent the flange. The annular nut body has side surfaces and internal threads that are threaded onto the external threads of the main shaft. The annular hydraulic piston has side surfaces that slidingly engage the side surfaces of the annular nut body. The annular mantle has an upper neck portion and a lower edge portion. The main shaft extends through the upper neck portion. The upper neck portion of the annular mantle is compressed between the flange of the main shaft and the annular hydraulic piston.

Installation problems often arise because the headnut assembly must be tightened into contact with the mantle to prevent excess "play" between the components. The headnut is typically used to forcibly secure the mantle to the crushing head assembly by applying a large downward force on the top of the mantle. The headnut includes an internally threaded surface that engages an externally threaded surface on the mainshaft or a bearing sleeve supported on the mainshaft. In conventional gyratory crushers, downward force is applied to the mantle by screwing down the internally threaded headnut on the mating threads of the externally threaded mainshaft bearing sleeve. The turning effort is typically applied by a special wrench having a protruding arm. The large amount of turning effort that is needed to tighten down the headnut often requires the use of difficult mechanical operations to create the sufficient locking force to adequately secure the mantle on the mainshaft.

The inventors of the present disclosure identified the problems associated with the installation of the headnut and the difficult mechanical operation to provide the required holding force on the top edge of the mantle. As a result, the retainer assembly of the present disclosure was developed to solve the problems identified by the inventors.

The present disclosure relates to a method and system for securing a mantle to a mainshaft of a gyratory crusher. More specifically, the present disclosure relates to a retainer assembly that improves the ease of connection between the mantle and mainshaft of a gyratory crusher.

The retainer assembly of the present disclosure includes a headnut having a body defined by a first face surface and a second face surface. The headnut is an annular member that includes a series of threads designed to be received by a mating series of threads on a bearing sleeve installed on the mainshaft. The headnut further includes a first series of bores and a second series of bores.

A burn ring is positioned below the headnut and is initially attached to the headnut by a series of connectors. The series of connectors extend through the first series of bores and are received in corresponding bores formed in the burn ring. When the burn ring is connected to the headnut by the series of connectors, the combination of the headnut and burn ring can be lifted into place above the mainshaft as a single unit.

A plurality of jacking bolts are received in the second series of bores formed in the headnut. Each of the jacking bolts are threaded into one of the bores of the second series of bores. During the initial installation of the headnut and burn ring on the mainshaft, the jacking bolts do not extend past the second face surface of the headnut. When the jacking bolts are rotated, the lower end of the jacking bolt extends past the second face surface of the headnut.

The retainer assembly further includes a hydraulic kit that includes a plurality of hydraulic cylinders. The hydraulic cylinders are connected to each other by a hydraulic fluid line. The hydraulic fluid line, in turn, is connected to a supply of pressurized hydraulic fluid. When the pressurized hydraulic fluid is supplied to the hydraulic cylinders, a cylinder rod and connected end effector extend away from the cylinder body. When the hydraulic fluid is removed, the cylinder rod and end effector are retracted in a direction toward the cylinder body.

In one embodiment of the present disclosure, the cylinder body includes threads formed along the outer surface of the cylinder body. The threads formed on the cylinder body allow the hydraulic cylinder to be securely received within one of the second series of bores formed in the headnut. Prior to being received in the second series of bores, the series of connectors used to attach the headnut to the burn ring must first be removed. Thus, the headnut will be disconnected from the burn ring, other than through friction forces created by the dowel pins, before the hydraulic cylinders can be installed.

Once the hydraulic cylinders are installed, the pressurized hydraulic fluid can be supplied to the hydraulic cylinders. The pressurized hydraulic fluid causes the cylinder rod and end effector to extend away from the cylinder body and move into contact with the top face surface of the burn ring. The continued movement of the end effectors causes the burn ring to be pressed into contact with the mantle and the headnut to move upward. This movement creates a gap between the burn ring and the headnut while also creating a locking force between the threads of the headnut and the threads of the bearing sleeve positioned on the mainshaft.

After the gap has been created, the plurality of jacking bolts are rotated until the end of the jacking bolt contacts the burn ring. In one exemplary embodiment, when all of the jacking bolts have been rotated into contact with the burn ring, one or more shims can be inserted into the gap. The shims are each designed with cutouts that allow the shims to be inserted when the jacking bolts are extended and the hydraulic cylinders are still pressurized.

With the jacking bolts and shims in place, the supply of pressurized hydraulic fluid can be removed, which causes the end effectors to retract. The jacking bolts and shims maintain the gap and the locking force after removal of the pressurized hydraulic fluid. In an exemplary embodiment, the cutouts formed in the shims also allow for expansion of the shims during pressure such that the material of shim can expand and fill a portion of the cutouts. The plurality of hydraulic cylinders can be removed from the headnut.

A headnut cover can then be installed over the headnut to protect the headnut and burn ring during operation of the gyratory crusher. The headnut cover is installed using a series of connectors that can be removed to allow removal of the headnut cover when the mantle needs to be removed and replaced.

Various other features, objects and advantages of the invention will be made apparent from the following description taken together with the drawings.

The drawings illustrate the best mode presently contemplated of carrying out the disclosure. In the drawings:.

<FIG> and <FIG> generally illustrate several of the components of the retainer assembly constructed in accordance with the present disclosure. As illustrated in <FIG>, the illustrated components of the retainer assembly <NUM> are designed to be received along a bearing sleeve <NUM> that is positioned to surround a main shaft <NUM> of a gyratory crusher. The mainshaft <NUM> receives and supports a mantle <NUM> that is fitted around the outside of the mainshaft <NUM>. The mantle <NUM> provides a replaceable wearing surface that needs to be replaced upon wear. The mantle <NUM> is held in place along the mainshaft <NUM> through use of the retainer assembly <NUM>.

As shown in <FIG>, the retainer assembly <NUM> includes a headnut <NUM> and a burn ring <NUM>. The headnut <NUM> is a generally annular member formed from a durable metal material that includes a series of internal threads <NUM> formed along an annular inner surface <NUM>. The internal threads <NUM> are designed to threadedly engage a series of external threads <NUM> formed on the lower end of the bearing sleeve <NUM>. As the illustrated portion of the retainer assembly <NUM> is rotated along the external threads <NUM>, the retainer assembly <NUM> contacts a top edge <NUM> of the mantle <NUM> to hold the mantle <NUM> in place along the mainshaft. As illustrated in <FIG>, the mainshaft <NUM> includes a lifting lug <NUM> along the top end that provides a point of attachment for removing the entire mainshaft.

Referring back to <FIG>, the headnut <NUM> includes a main body <NUM> that extends between a first, top face surface <NUM> and a second, bottom face surface <NUM>. The annular main body <NUM> that extends between the top face surface <NUM> and the bottom face surface <NUM> further defines the inner surface <NUM> that includes the threads <NUM>. In accordance with the present disclosure, the headnut <NUM> includes a first series of bores <NUM> that each extend through the body from the first face surface <NUM> to the second face surface <NUM>. In the embodiment illustrated, the first series of bores <NUM> includes a total of four bores although other numbers are possible. The headnut <NUM> also includes a second series of bores <NUM> that also extend through the body from the first face surface <NUM> to the second face surface <NUM>. In the embodiment illustrated, the second series of bores <NUM> eight bores although other numbers are possible.

In the embodiment shown in <FIG>, each of the second series of bores <NUM> are designed to receive one of a plurality of jacking bolts <NUM>. Each of the jacking bolts <NUM> includes an externally threaded main body that extends between a head <NUM> and a contact end <NUM>. Each of the second series of bores <NUM> includes a threaded inner surface that is designed to threadedly receive and engage the outer surface of one of the jacking bolts <NUM>.

The first series of bores <NUM> are designed to initially receive one of a plurality of connectors <NUM> that include an externally threaded outer shaft that extends between a head <NUM> and a lower end <NUM>. A washer <NUM> is included as part of the connector <NUM> to prevent the head <NUM> from entering into the respective bore <NUM>.

In the embodiment illustrated in <FIG>, the retainer assembly <NUM> includes the burn ring <NUM>. However, it is contemplated that the retainer assembly <NUM> could be constructed in some embodiments in which the burn ring <NUM> is eliminated. In such an embodiment, the top edge of the mantle would be formed from a stronger material and would replace the function of the burn ring as discussed below. In another contemplated embodiment, the thickness of the burn ring <NUM> could be greatly reduced and the burn ring <NUM> could be formed from a stronger material such that a reduced thickness burn ring could carry out the functions set forth below. In the embodiment shown in <FIG>, the burn ring <NUM> includes a first face surface <NUM> and a second face surface <NUM> that define the thickness of the annular body. As illustrated in <FIG>, the burn ring <NUM> includes a plurality of dowel pins <NUM> that are each received within one of a plurality of dowel pin bores <NUM>, which are best shown in <FIG>. Each of the dowel pin bores <NUM> is sized to receive a first end <NUM> of the dowel pin <NUM>. The upper end of the dowel pin bore <NUM> defines a support shoulder <NUM> that allows the dowel pin <NUM> to securely seat within the top end of the dowel pin bore <NUM>. The dowel pin <NUM> is designed to be pressed into place in the burn ring <NUM> as shown in <FIG>. In a contemplated alternate embodiment, the dowel pins <NUM> could be welded in place from underneath or a combination of welding and friction could be used to hold the dowel pins <NUM> in place. The outer diameter of the dowel pin <NUM> is designed to be received within a receiving portion <NUM> that is formed as part of a cover member bore <NUM> that also extends between the first face <NUM> and the second face surface <NUM> of the headnut <NUM>.

As can be understood in <FIG>, when the headnut <NUM> is moved downward toward the burn ring <NUM>, the series of dowel pins <NUM> are received within the receiving portions <NUM> of the cover member bores <NUM> such that the dowel pins <NUM> create a friction fit to retain the burn ring <NUM> in contact with the second face surface <NUM> of the headnut <NUM>, as best shown in <FIG>. In the configuration shown in <FIG>, the headnut <NUM> and the burn ring <NUM> are joined to each other in an initial configuration. The dowel pins <NUM> create a light press fit that holds the two components in this initial configuration.

Referring now to <FIG>, when the headnut <NUM> and the burn ring <NUM> are joined to each other through the use of the dowel pins, the headnut <NUM> can be more securely connected to the burn ring <NUM> by using the series of connectors <NUM>. As indicated previously, each of the connectors <NUM> includes a head <NUM> and an externally threaded shaft <NUM>. The lower end of the externally threaded shaft <NUM> is threadedly received within one of a plurality of attachment bores <NUM> that extend through the burn ring <NUM> from the first face surface <NUM> to the second face surface <NUM>. The washer <NUM> is positioned below the head <NUM> to hold the head of the connector <NUM> above the inner diameter of the first series of bores <NUM>. The threaded interaction between the shaft <NUM> and the internal threads formed in the attachment bore <NUM> securely attaches the headnut <NUM> to the burn ring <NUM>. As illustrated in <FIG>, in the embodiment illustrated, four separate connectors <NUM> are utilized and are spaced around the outer diameter of the headnut <NUM>.

Referring now to <FIG>, when the series of connectors <NUM> are used to join the headnut <NUM> to the burn ring <NUM>, each of the individual jacking bolts <NUM> can be threadedly inserted into the second series of bores <NUM>. Each of the jacking bolts <NUM> includes a recessed engagement portion <NUM> that extends into the body of the jacking bolt <NUM> from the top head portion <NUM>. The main body of the jacking bolt <NUM> includes a series of external threads that engage a series of internal threads formed within each of the second series of bores <NUM>. The length of the jacking bolt <NUM> is selected such that the contact end <NUM> is slightly spaced from the contact pads <NUM> that are slightly recessed from the first face surface <NUM> of the burn ring <NUM>. In this manner, the jacking bolt <NUM> is entirely received within one of the second series of bores <NUM> during the initial installation process and does not exert any force on the burn ring <NUM>.

As can be seen in <FIG>, a series of lifting bolts <NUM> can be installed on the first face surface of the headnut <NUM>. The lifting bolts <NUM> provide a point of attachment for lifting the combination of the headnut <NUM> and burn ring <NUM>. As illustrated in <FIG>, when the retainer assembly <NUM> is being lifted, the entire retainer assembly <NUM> can be lowered until the threaded portion of the headnut <NUM> contacts the external threads <NUM> formed on the bearing sleeve <NUM>. <FIG> illustrates the initial contact between the threads <NUM> formed on the bearing sleeve <NUM> and the threads <NUM> formed along the inner surface <NUM> of the headnut <NUM>. Upon this initial interaction, the combination of the headnut <NUM> and the burn ring <NUM> can be rotated using hand tools to cause the headnut <NUM> and burn ring <NUM> to move in a downward direction as illustrated by arrow <NUM>. The rotation of the retainer assembly <NUM> can continue until the second face surface <NUM> of the burn ring comes into contact with the top edge <NUM> of the mantle <NUM>. This interaction is best shown in <FIG>. During installation in accordance with the present disclosure, the combination of the headnut and burn ring are threaded into place utilizing only a relatively small amount of force, such as by hand or by using a hand operated tool. The hand-tightening of the headnut and burn ring into contact with the top edge <NUM> of the mantle <NUM> is the initial step in the attachment process in accordance with the present disclosure. <FIG> shows this initial positioning of the retainer assembly along the mainshaft <NUM>. In this position, the retainer assembly lightly holds the mantle <NUM> in place. In this configuration, the connectors <NUM> are still used to connect the headnut <NUM> to the burn ring <NUM>.

Referring now to <FIG>, once the combination of the headnut <NUM> and the burn ring <NUM> are installed along the bearing sleeve <NUM>, each of the individual connectors <NUM> can be removed and a hydraulic kit <NUM> can be installed to perform the next step in the attachment process for securing the mantle <NUM> to the mainshaft. The hydraulic kit <NUM> is part of the entire retainer assembly and is used during the installation process as will be described. Although a hydraulic kit <NUM> is shown, other pressurized fluids or gases could be used in place of hydraulic fluid.

In the embodiment shown in <FIG>, the hydraulic kit <NUM> includes a plurality of individual hydraulic cylinders <NUM> that are each connected to each other through a fluid line <NUM>. The hydraulic fluid line <NUM> provides a fluid connection for hydraulic fluid to pass between each of the individual cylinders <NUM>. The end hydraulic cylinder <NUM> is connected to a supply of pressurized hydraulic fluid <NUM> through a supply line <NUM>. When the supply line <NUM> is connected to the supply of hydraulic fluid <NUM>, the pressurized hydraulic fluid can flow between each of the individual hydraulic cylinders <NUM> in a well-known manner. The supply of hydraulic fluid <NUM> can be any type of hydraulic fluid supply that provides pressurized fluid at a desired fluid pressure. A hand pump is shown in the embodiment of <FIG>, although other sources of pressure are contemplated as being within the scope of the present disclosure. In addition, although pressurized hydraulic fluid is described, other pressurized liquids or gases could be connected to the plurality of cylinders to provide the required driving force to move the cylinder rod and internal piston. As an exemplary alternate embodiment, the supply of pressurized fluid could be pressurized air or other gas and the cylinders could be gas or air actuated cylinders.

Referring now to <FIG>, before the individual hydraulic cylinders <NUM> can be installed, each of the connectors <NUM> are removed from the respective first series of bores <NUM>. Once each of the connectors <NUM> have been removed from the first series of bores <NUM>, the individual hydraulic cylinders can be installed in the same first series of bores <NUM>. Thus, the plurality of connectors <NUM> must be removed before the plurality of hydraulic cylinders <NUM> can be installed.

Referring now to <FIG>, each of the individual hydraulic cylinders <NUM> includes a main cylinder body <NUM>. The cylinder body <NUM> includes a series of external threads <NUM>. The external threads <NUM> on the cylinder body <NUM> are configured to threadedly engage the internal threads formed along the inner surface of each of the first series of bores <NUM>. In this manner, the hydraulic cylinders <NUM> can be threadedly received within the plurality of first series of bores <NUM>.

As illustrated in <FIG>, each of the hydraulic cylinders <NUM> includes an end effector <NUM> that is attached to a cylinder rod <NUM>. The cylinder rod <NUM> is designed to be extended and retracted from within the cylinder body <NUM> upon application of pressurized hydraulic fluid to the hydraulic cylinder <NUM>. The end effector <NUM> is shown in <FIG> in a retracted position in which the end effector <NUM> is slightly spaced from the first face surface <NUM> of the burn ring <NUM>. Thus, in the non-pressurized condition, the end effector <NUM> does not exert any force on the burn ring <NUM>.

During the pressurization process, hydraulic fluid is applied to each of the individual hydraulic cylinders <NUM> as best shown in <FIG>. When hydraulic fluid is applied to the hydraulic cylinder <NUM>, the cylinder rod <NUM> extends from the cylinder body <NUM> such that the end effector <NUM> contacts the first face surface <NUM> of the burn ring <NUM>. Since the end effector <NUM> is moved under the pressure created by the supply of hydraulic fluid, the downward movement of the end effector <NUM> creates a corresponding upward movement of the headnut <NUM> away from the burn ring <NUM>. The upward movement of the headnut <NUM> creates a physical interaction between the threaded portion of the headnut <NUM> and the threaded portion of the bearing sleeve <NUM>. The physical interaction between the threaded portions of the headnut <NUM> and the bearing sleeve <NUM> creates a locking force on the burn ring <NUM> and thus the mantle <NUM>.

As illustrated in <FIG>, when the individual hydraulic cylinders <NUM> are pressurized, the downward movement of the end effector <NUM> creates a gap <NUM> between the second face surface <NUM> of the headnut <NUM> and the first face surface <NUM> of the burn ring <NUM>. The gap <NUM> created can have range of sizes. In the embodiment illustrated, the gap <NUM> has a dimension of approximately <NUM> millimeters, although other sizes for the gap <NUM> are certainly contemplated as being within the scope of the present disclosure.

Referring now to <FIG>, once the gap <NUM> has been created through the pressurization of the individual hydraulic cylinders <NUM>, the size of the gap can be maintained by use of the series of jacking bolts <NUM>. Specifically each of the individual jacking bolts <NUM> is rotated within the respective bore to cause the contact end <NUM> of the jacking bolt <NUM> to contact the first surface <NUM> of the burn ring <NUM> as illustrated in <FIG>. Since each of the jacking bolts <NUM> is threaded into one of the second series of bores <NUM>, the plurality of jacking bolts <NUM> can be used to maintain the gap <NUM> even when the individual hydraulic cylinders <NUM> are depressurized.

In accordance with the present disclosure, once the jacking bolts <NUM> are rotated into contact with the burn ring <NUM>, one or more individual shims <NUM> can be inserted into the gap <NUM> to maintain the gap during operation of the gyratory crusher. In the embodiment illustrated in <FIG>, the shims <NUM> are formed as separate segments that can be combined to create either an entire annular ring or portions of an annular ring. It is contemplated that multiple numbers of shims <NUM> could be utilized to help maintain the size of the gap between the headnut and the burn ring. In the embodiment shown in <FIG>, the individual shims include a series of cutouts <NUM> that are sized to receive the contact end of each of the jacking bolts <NUM> and the dowel pins. In this manner, the shims <NUM> can be inserted as shown in <FIG> while the jacking bolts <NUM> maintain the size of the gap <NUM> and the dowel pins join and align the headnut and the burn ring. Further, the cutouts <NUM> can also allow the shim <NUM> to be inserted while the hydraulic cylinders are pressurized and the dowel pins are installed, as shown in <FIG>.

Once the individual shims <NUM> have been securely positioned in place, the hydraulic fluid applied to each of the individual hydraulic cylinders can be removed. The combination of the jacking bolts <NUM> and shims <NUM> maintain the gap <NUM> and also maintain the physical interaction between the threaded portions of the headnut <NUM> and the threaded portion of the bearing sleeve. After the hydraulic fluid has been removed from each of the cylinders <NUM>, the threaded bodies of each of the cylinders <NUM> can be rotated to remove the hydraulic cylinders <NUM> from the headnut <NUM>.

<FIG> illustrates the installed headnut and burn ring after the removal of the hydraulic cylinders as compared to the embodiment shown in <FIG>. Once the hydraulic cylinders of the hydraulic kit are removed, a headnut cover <NUM> can be installed over the combination of the headnut <NUM> and the burn ring <NUM>. The headnut cover <NUM> is designed to cover the headnut <NUM> during operation of the gyratory crusher to reduce the damage to the headnut <NUM>. The headnut cover <NUM> is an annular member that includes a top face surface <NUM> that includes a plurality of bores <NUM> that are each designed to receive threaded connector <NUM>. Each threaded connector <NUM> includes a threaded shaft <NUM> and a head <NUM>, as illustrated in <FIG>. Referring back to <FIG>, the headnut cover <NUM> includes a plurality of lifting lugs <NUM> that provide a point of attachment for lifting the headnut cover <NUM> and installing it over the headnut <NUM>.

As illustrated in the section view of <FIG>, the headnut cover <NUM> includes a top wall <NUM> and a depending side wall <NUM>. The depending side wall <NUM> is connected to the top wall <NUM> along the radial outer edge <NUM>. The side wall <NUM> is designed to have an inner circumference that is designed to fit over the outer surface <NUM> of the headnut <NUM>.

The bores <NUM> extending into the top face surface <NUM> are each designed to include an internal shoulder <NUM> that is designed to receive the head <NUM> of one of the connectors <NUM>. <FIG> illustrates the mounting of the headnut cover <NUM> onto the combination of the headnut <NUM> and the burn ring <NUM>. In this configuration, the threaded shaft of the connector <NUM> is received within the internal threaded portion of one of the cover member bores <NUM>. In this manner, headnut cover <NUM> can be securely attached to the headnut as best illustrated in <FIG>.

During replacement of mantle <NUM>, headnut cover <NUM> is first removed from the headnut <NUM> by removing the series of connectors <NUM>. Once the headnut cover <NUM> is removed, the burn ring <NUM> can be cut using a torch, which removes the tension on the headnut <NUM>. The headnut <NUM> can then be rotated away from the mantle <NUM> and the mantle removed from the mainshaft.

In another embodiment, once the headnut cover <NUM> has been removed, the plurality of hydraulic cylinders <NUM> could be reinstalled into the first series of bores in the headnut. Once the hydraulic cylinders <NUM> of the hydraulic kit are reinstalled, the pressurized hydraulic fluid can again be applied to the hydraulic cylinders <NUM> to help loosen the connection between the headnut and the mainshaft. Once the threaded connection is loosened, the jacking bolts could be retracted combination of the headnut and burn ring could be removed, which would allow for reuse of the burn ring.

Claim 1:
A retainer assembly (<NUM>) for securing a mantle (<NUM>) on a mainshaft (<NUM>) of a gyratory crusher, the assembly comprising:
a headnut (<NUM>) having a body (<NUM>) defined by a first face surface (<NUM>) and a second face surface (<NUM>), the headnut including first series of bores (<NUM>) extending through the body and a second series of bores (<NUM>) extending through the body;
a plurality of jacking bolts (<NUM>) each received in one of the second series of bores (<NUM>) formed in the headnut (<NUM>); and
a plurality of cylinders (<NUM>) and a supply (<NUM>) of pressurized fluid in communication with the plurality of cylinders (<NUM>), wherein the plurality of cylinders (<NUM>) are each received in one of the first series of bores (<NUM>) in the headnut,
wherein when the supply (<NUM>) of pressurized fluid is supplied to the plurality of cylinders (<NUM>), a gap is created between the second face surface (<NUM>) of the headnut (<NUM>) and the mantle (<NUM>).