Patent Description:
In a crusher, more specifically a primary gyratory crusher, the main shaft rotates as the crusher is idling and when the crusher is crushing incoming feed material. Main shaft/head spin can be utilized to assess the operational health of the machine when the crusher is idling and/or crushing.

During idling, the typical observed value of the head spin is about <NUM> to <NUM> RPMs but this value can be impacted by different factors. One major factor that affects head spin is the fit between the spider bushing and the main shaft upper journal. If the spider bushing starts to lose the friction fit with the main shaft upper journal, the reduction in friction between these components and in turn the main shaft/ head spin can become elevated beyond the observed "baseline".

If the head spin is monitored and compared to a baseline value measured during normal operation with the crusher in a desired condition, it is possible to determine when the spider bushing is become worn. Further, by monitoring head spin relative to the baseline value other components that can contribute to a change in head spin such as the dust seal and the fit between the main shaft lower journal and the eccentric bushing, can be analyzed for wear. In addition, head spin can also be potentially impacted by the weight of the mantle. Since the weight of the mantle can change over time as the mantle becomes worn, a minor change in head spin could also indicate and potentially allow for the monitoring of mantle wear life. <CIT> discloses an assembly and method for restricting spinning in a gyratory crusher.

By monitoring head spin, the present disclosure will allow for greater visibility on the operational health of a gyratory crusher which will help to prevent unplanned downtime and to minimize production losses.

In addition to monitoring head spin, the system and method of the present disclosure will allow for the monitoring of the vertical displacement of the main shaft in relationship to the crusher. By monitoring the vertical displacement of the main shaft, this present disclosure will allow for the detection of main shaft jumps which have a negative impact on the overall operational health of the crusher. By monitoring the vertical position, the present disclosure will allow for the potential deletion of the existing sensor that is utilized to monitor the position of the main shaft, which is done by monitoring the MPS piston.

The method and system of the present disclosure utilizes magnetic flux deviations caused by the moving crusher head to identify the rotation and location of the moving crusher head. A magnetic sensor, such as a magnetometer, is utilized to detect changes in the magnetic flux. The data generated by a magnetic sensor can be interpreted by a controller to provide an analysis of main shaft head spin and vertical displacement.

A magnetic element in the form of a lifting lug is mounted to a top end of the main shaft, which can be sensed by the magnetic sensor. The magnetic element is found on top of the main shaft. The lifting lug is formed from a ferromagnetic metallic material. The lifting lug is typically used for lifting the main shaft during assembly of the crusher. The lifting lug has a rectangular shape that is sufficient to disrupt the magnetic flux in a way that a magnetometer will be able to identify the rotation and location of the lifting lug and associated main shaft. The lifting lug is located within a spider bushing cavity during operation of the crusher. The spider bushing cavity is surrounded by metal such that the spider bushing cavity will act as a "Faraday's cage" and prevent magnetic/ electrical interference from impacting the reading by the magnetometer. Although the lifting lug is one type of magnetic element, different masses of a ferromagnetic material could be attached to the top end of the main shaft. Such mass of material could also be sensed by the magnetometer in the same way as the lifting lug.

In a contemplated exemplary embodiment of the present disclosure, if a stronger magnetic field is required to improve sensing, the magnetic element could include a permanent magnet installed on the top end of the main shaft either alone or in combination with the lifting lug. In an embodiment in which the magnetic element includes both the lifting lug and the permanent magnet, the permanent magnet could be fit into the existing hole formed in the lifting lug. The hole in the lifting lug is currently utilized to install the shackle when lifting the main shaft. If a permanent magnet is utilized, it will be installed within the lifting lug after the main shaft is installed into the crusher.

The magnetometer utilized in the present disclosure is able to sense the changes in the magnetic field generated by a rotating main shaft. The rotation of the main shaft will cause the magnetic element to create a disruption in a magnetic flux. The change in the magnetic flux will translate into an output signal generated by the magnetometer. The output signal from the magnetometer can in turn be interpreted to provide a representation of main shaft head spin and/or the vertical displacement of the main shaft.

In accordance with the present disclosure, the utilization of magnetic flux caused by changes in the magnetic field is used to monitor the location and rotation of the crusher "head". The method and system of the present disclosure can be retrofit to existing crushers and will be able to withstand the punishing environment that these crushers are subjected to. The ability to monitor main shaft/ head spin has been something desired for many years and the present disclosure solved this challenge in addition to allowing for the monitoring of main shaft jump.

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 a gyratory rock crusher <NUM> constructed in accordance with the present disclosure. As can be seen in <FIG>, the gyratory rock crusher <NUM> includes a shell assembly <NUM> that is formed from an upper top shell <NUM> joined to a lower top shell <NUM>. The top shells <NUM>, <NUM> support a series of concaves <NUM> that are positioned along the inner surface of the shell assembly <NUM> to define a generally tapered frustoconical inner surface <NUM> that directs material from an open top end <NUM> downward through a converging crushing cavity <NUM> formed between the inner surface <NUM> defined by the row of concaves <NUM> and an outer surface <NUM> of a frustoconical mantle <NUM> positioned on a gyrating main shaft <NUM>. Material is crushed over the height of the crushing cavity <NUM> between the inner surface <NUM> and the outer surface <NUM> as the main shaft <NUM> gyrates, with the final crushing occurring within the crushing gap <NUM>.

As best seen in <FIG> and <FIG>, the upper end <NUM> of the main shaft is supported within a spider bushing <NUM> that is contained within a central hub <NUM> of a spider <NUM>. The spider <NUM> is mounted to the upper rim <NUM> of the upper top shell <NUM> and includes at least a pair of spider arms <NUM>. As illustrated in <FIG>, each of the spider arms <NUM> receives a spider arm shield <NUM> that provides wear protection for the underlying spider arm <NUM>. Each of the spider arms <NUM> includes a generally hollow, open cavity <NUM>. The spider arms <NUM> support the central hub <NUM> such that the central hub <NUM> can provide rotating support for the upper end <NUM> of the rotating main shaft <NUM>.

Referring back to <FIG> and <FIG>, the center hub <NUM> includes a circular inner ridge <NUM> that helps to support a spider cap <NUM>. The spider cap <NUM> includes an outer wall <NUM> that is supported on the shoulder <NUM> of the center hub <NUM>. The spider cap <NUM> provides additional wear protection and creates a spider cap cavity <NUM>. In the embodiment shown in <FIG>, a metallic cover plate <NUM> is attached to the inner ridge <NUM> of the central hub <NUM>. The cover plate <NUM> includes a cylindrical center section <NUM> that has a circular outer wall <NUM> extending upward from the cover plate <NUM>. The outer wall <NUM> supports a top wall <NUM>. The cover plate <NUM> is securely attached to the inner ridge <NUM> such that the cover plate <NUM> creates an enclosed spider bushing cavity <NUM>.

As can be seen in <FIG> and <FIG>, the spider bushing <NUM> is secured to the central hub <NUM> by a series of connectors <NUM>. The connectors <NUM> securely hold the spider bushing <NUM> in place while allowing the upper end <NUM> of the main shaft to both move vertically and rotate within the stationary central hub <NUM>.

As can be seen in <FIG> and <FIG>, the upper end <NUM> of the main shaft receives a lifting lug <NUM> mounted to a top section <NUM>. The lifting lug <NUM> and the top section <NUM> are attached to the upper end <NUM> of the main shaft and provide a point of attachment for the main shaft such that the entire main shaft can be lifted utilizing mechanical equipment, such as an overhead crane. The lifting lug <NUM> is formed from a ferromagnetic metal material that includes a lifting hole <NUM> that extends through the width of the lifting lug <NUM>. The lifting hole <NUM> provides a point of attachment for lifting the entire main shaft during assembly of the gyratory crusher.

As can be seen in <FIG> and <FIG>, the lifting lug <NUM> is generally aligned with the center section <NUM> of the cover plate <NUM>. In this manner, the lifting lug <NUM> is completely contained within the spider bushing cavity <NUM> defined by the cover plate <NUM> and the side walls <NUM> of the upper portion of the central hub <NUM> which terminate with the inner ridge <NUM>. Since the central hub <NUM> and the cover plate <NUM> are both formed from ferromagnetic material, the spider bushing cavity <NUM> creates a "Faraday's cage" surrounding the lifting lug <NUM>.

Referring now to <FIG>, and in accordance with the present disclosure, the gyratory crusher includes a system for monitoring at least one motion parameter of the main shaft during operation. The monitoring system is able to detect both the rotational movement of the main shaft, as shown by arrow <NUM> in <FIG>, and the vertical movement of the main shaft, as shown by arrow <NUM> also in <FIG>. As best illustrated in <FIG>, the sensing system includes a magnetic sensor <NUM> positioned within the spider bushing cavity <NUM>. The magnetic sensor <NUM> is supported by a mounting bracket <NUM> which in turn is mounted through to the top end of the spider bushing <NUM> by a connector <NUM>. A sensor cable <NUM> extends through the open cavity <NUM> of the spider arm <NUM> and out of the outer rim <NUM>. The cable <NUM> is connected to a controller <NUM>, which is shown in <FIG>. The controller <NUM> receives the output signal from the magnetic sensor <NUM> and interprets the output signal from the magnetic sensor to monitor the rotational movement of the main shaft and the vertical movement of the main shaft in a manner as will be described in greater detail below.

In the preferred embodiment of the present disclosure, the magnetic sensor <NUM> is a stationary magnetometer that is operable to detect changes in the magnetic flux within the spider bushing cavity <NUM>. A magnetometer is a special type of magnetic sensor that is able to measure the vector component of a magnetic field. The magnetometer generates an output signal that is based on the vector component of the magnetic field. If a magnetic member formed from a ferromagnetic material moves into the magnetic field near the stationary magnetometer, the ferromagnetic material will disrupt the magnetic field and create a change in the magnetic flux sensed by the magnetometer. The changes in the magnetic flux caused by the magnetic member can be interpreted to determine the direction of movement of the ferromagnetic member.

In the present disclosure, the magnetic member sensed by the magnetometer is the lifting lug <NUM>. The lifting lug <NUM> is formed from a relatively large portion of ferromagnetic metallic material. During head spin or jumping of the main shaft, the lifting lug <NUM> will either rotates or move vertically within the spider bushing cavity <NUM>. The movement of the lifting lug <NUM> is sufficient enough to disrupt the magnetic flux in a way that the magnetometer is able to identify either the rotational movement of the lifting lug or the vertical movement of the lifting lug. In an alternate embodiment in which the main shaft does not include the lifting lug <NUM>, another mass of ferromagnetic material could be mounted to the top end of the main shaft. This mass of material would also be sensed by the magnetometer. As indicated previously, the spider bushing cavity <NUM> generally forms a "Faraday's cage" that prevents magnetic/electrical interference from impacting the reading made by the magnetometer. In this manner, only the movement of the lifting lug will be sensed by the magnetometer.

Although sensing the rotational movement and the vertical movement of the lifting lug or similar magnetic member utilizing the magnetic sensor is one embodiment of the present disclosure, in another embodiment of the present disclosure, the magnetic member could be a permanent magnet <NUM> mounted to the top end of the main shaft. The permanent magnet <NUM> could be mounted alone or could be mounted to the mass of ferromagnetic material. In the embodiment illustrated, the permanent magnet <NUM> is inserted into the lifting hole <NUM> formed in the lifting lug <NUM>, as best shown in <FIG>. In the embodiment shown in <FIG>, the permanent magnet <NUM> has a cylindrical form and extends from a first end <NUM> to a second end <NUM>. As is well-known, the permanent magnet <NUM> creates a magnetic field <NUM> that extends between the first and second ends <NUM>, <NUM>. If the permanent magnet <NUM> is utilized, the permanent magnet <NUM> is installed after the main shaft <NUM> has been installed into the crusher and the lifting lug <NUM> is no longer needed during operation. The permanent magnet <NUM> could be removed later if the lifting lug <NUM> is needed for replacement or servicing.

As can be understood in <FIG>, the magnetic field <NUM> created by the use of the permanent magnet <NUM> as the magnetic element enhances the magnetic field within the spider bushing cavity <NUM>, as is clearly shown in <FIG>. As illustrated in <FIG>, the magnetic sensor <NUM> is positioned in close proximity to the permanent magnet <NUM> such that the magnetic field <NUM> can be easily sensed by the magnetic sensor <NUM>. If the main shaft begins to rotate, as indicated by arrow <NUM>, or moves vertically, as indicated by arrow <NUM>, the change in the magnetic field created by the movement of the permanent magnet <NUM> will be sensed by the magnetic sensor <NUM>. The change in the magnetic flux is sensed by the magnetic sensor <NUM> and an output signal is relayed to the controller <NUM> such that the controller <NUM> can provide indications to a user/operator that either vertical movement of the main shaft has been detected or rotational movement of the main shaft has been detected.

<FIG> is an illustration of the relationship between the magnetic field <NUM> generated by the permanent magnet and magnetic flux. The relationship between the changing magnetic flux generated by a changing magnetic field is sensed by the magnetic sensor <NUM> and is used by the controller to determine whether there is vertical movement or rotational movement of the main shaft. Although a permanent magnet <NUM> is illustrated in the embodiment of the drawing figures, the permanent magnet <NUM> could be eliminated and the disruption to the magnetic flux sensed by the magnetic sensor <NUM> would be caused only by the ferrometallic material of the lifting lug <NUM>. Such disruption could be sensed by the magnetic sensor and the analyzed by the controller. However, the use of the permanent magnet <NUM> is believed to create a stronger magnetic field which would make it easier to identify smaller changes in the magnetic flux.

<FIG> provides a schematic illustration of the sensing system <NUM> of the present disclosure. The sensing system <NUM> includes the controller <NUM> that is in communication with the magnetic sensor <NUM>. The magnetic sensor <NUM> is positioned in close relationship to the magnetic element, such as the lifting lug <NUM> which may or may not include the permanent magnet. As indicated previously, the lifting lug <NUM> is movable both vertically and rotates depending upon the operation of the gyratory crusher and the associated main shaft. The magnetic sensor <NUM> senses the change in the magnetic flux caused by either the vertical movement or the rotational movement of the main shaft. The magnetic sensor <NUM> operates to create an electrical signal that is representative of the movement and change in the magnetic flux. The electrical signal generated by the magnetic sensor <NUM> is relayed to the controller <NUM>. The controller <NUM>, in turn, is programmed to interpret the changing electrical output signal from the magnetic sensor <NUM> and to generate an output signal that provides information as to either the rotational movement of the main shaft or the vertical movement of the main shaft. In the embodiment shown in <FIG>, the controller <NUM> is connected to a visual display <NUM> such that the sensed information can be relayed to an operator/user. Although a display <NUM> is illustrated, it should be understood that the controller <NUM> could relay information to an operator/user in other manners, such as through visual indicators, audible indicators or any other manner that would be acceptable to the operator of the gyratory crusher.

In the embodiment shown in <FIG>, a user input <NUM> is also connected to the controller <NUM> such that an operator/user can enter operational parameters and control values into the controller <NUM>. The user input <NUM> could be any type of conventional user input, such as a keyboard, touchscreen, or any other type of input device that allows the user to enter information into the controller. The controller <NUM> is further connected to a power supply <NUM> that provides power for not only the controller <NUM> but also for the magnetic sensor <NUM>. The power supply <NUM> could be a battery power supply or a utility power supply depending upon the location and configuration of the controller <NUM>.

Claim 1:
A system for monitoring at least one motion parameter of a main shaft in a gyratory or cone crusher (<NUM>) comprising:
a magnetic element mounted to a top end of the main shaft (<NUM>), wherein the magnetic element is a lifting lug (<NUM>) formed of a ferromagnetic material capable of affecting a magnetic field;
a magnetic sensor (<NUM>) positioned in proximity to the magnetic element and operable to detect changes in a magnetic flux caused by movement of the magnetic element; and
a controller (<NUM>) coupled to the magnetic sensor (<NUM>) to determine the at least one motion parameter based on the detected changes in the magnetic flux.