Patent Description:
Jaw crushers are utilized in many applications for crushing hard material. Such as pieces of rock and ore.

In use, the action of the moveable jaw causes the material fed to the jaw crusher to move down through a crushing chamber. Material to be crushed is fed to an intake for material to be crushed against wear plates on the moveable and stationary jaws. The crushed material leaves the jaw crusher via an outlet. The jaws are farther apart at the material intake than at the material outlet, forming a tapered crushing chamber so that the material is crushed progressively to smaller and smaller sizes as the material travels downward, until the material is small enough to escape from the material outlet at the bottom of the crushing chamber.

The jaw crusher further comprises a positioning device for positioning the movable jaw to a desired position with respect to the stationary jaw. The distance between the moveable jaw and the stationary jaw is referred to as the closed side setting (CSS), which is the shortest distance between the wear plate of the stationary jaw and the wear plate of the movable jaw.

It is desirable to be able to adjust the closed side setting (CSS) so as to change the size of product that may leave the crushing chamber via the outlet. It is known to adjust the CSS manually. This requires both machine and human intervention to ensure the required gap setting is achieved to obtain a specified final product. Although this setting can be achieved by the use of adjustable actuators, the measurement of the CSS is derived by traditional measurement methods, for example, a tape measure or a set gauge of a predefined size.

<CIT>describes a jaw crusher which has an adjustment mechanism coupled to the adjustable jaw for altering an angle of the adjustable jaw. A controller is configured to receive a measured parameter which is measured by a sensor and based at least in part on the measured parameter, the closed side setting is adjusted. Typically, the sensor measures a parameter that provides information on the condition of the jaw crusher such as, electrical resistance, oil condition, a hydraulic cylinder pressure, bearing temperature or power.

<CIT> uses a level sensor to control the size of crushed material and the amount of material in the crushing chamber is measured to alter the crushing capacity of the crusher. Documents <CIT> and <CIT> disclose a jaw crusher according to the preamble of claim <NUM>.

It is an object of the invention to remove the need for excessive machine downtime. It is another object of the present invention to eliminate human intervention when obtaining a CSS measurement. It is a further object of the present invention to obtain total wear values on the wear plates over time and compensate for this in the CSS position.

In accordance with a first aspect of the invention there is provided a jaw crusher according the subject-matter of claim <NUM>.

Advantageously, the present invention improves the measurement and control of the moveable jaw position.

Preferably, the drive cylinder is a hydraulic drive cylinder.

Advantageously, a hydraulic drive cylinder is easy to control and easy to maintain.

Preferably, the internally mounted sensor is centrally mounted in the drive cylinder.

Advantageously, centrally mounting the sensor creates a compact design and integrates it in the drive cylinder.

Preferably, the internally mounted sensor is a magnetostrictive linear position sensor.

Advantageously, a magnetostrictive sensor is exceptionally shock resistant, waterproof, operates over a wide temperature and pressure range, provides suitable resolution and measurement length.

The internally mounted sensor measures stroke distance of the drive cylinder. Measurement of stroke distance assists with determining the lifespan of components.

Preferably, measurement of the stroke distance provides a linear distance between the moveable jaw and the stationary jaw. Measurement of a linear distance improves measurement accuracy.

Measurement of the stroke distance provides a measure of total wear on the moveable jaw wear plate and fixed jaw wear plate. This measurement of wear allows for adjustment of the position of the moveable jaw.

Measurement of the stroke distance is constantly measured by the internally mounted sensor. Constant measurement allows for real time adjustment of the moveable jaw position and trend analysis recorded over time on a machine programmable logic controller PLC.

Preferably, the drive cylinder is driven to urge the moveable jaw and hence moveable jaw wear plate into contact with the fixed jaw wear plate to calibrate the distance measured by the internally mounted sensor by obtaining a zero CSS position. Contact between the moveable jaw and the stationary jaw in order assists in a determination of wear on the liners and when liners need to be replaced or turned.

Preferably, the jaw crusher further comprises a control block further comprises a pressure sensor configured to detect contact between the moveable jaw and the stationary jaw. The pressure sensor assists with positioning of the moveable jaw with respect to the stationary jaw.

In accordance with a second aspect of the invention there is provided a method for adjusting a jaw crusher, the jaw crusher comprising:.

The present invention improves the measurement and control of the moving jaw position and hence CSS.

Preferably, measurement of the stroke distance provides a measure of total wear on the moveable jaw wear plate and fixed jaw wear plate. Measurement of stroke distance assists with determining the lifespan of components.

Preferably, measurement of the stroke distance is used to set the position of the moveable jaw with respect to the stationary jaw. This allows for accurate control of the size of the product leaving the machine.

Preferably, a pressure sensor may be configured to detect contact between the moveable jaw and the stationary jaw. The pressure sensor assists with positioning or the moveable jaw with respect to the stationary jaw.

Preferably, the drive cylinder may urge the moveable jaw and hence moveable jaw wear plate into contact with the fixed jaw wear plate to calibrate the distance measured by the internally mounted sensor by obtaining a zero CSS position.

The invention will be more clearly understood from the following description of an embodiment thereof, given by way of example only, with reference to the accompanying drawings, in which:.

The present invention provides an apparatus and method for measuring and controlling the position of the moveable jaw of a jaw crusher with respect to the stationary jaw. This result is achieved by means of an adjustment device for adjusting the position of the moveable jaw relative to the stationary jaw. The adjustment device comprises a drive cylinder with an internally mounted sensor to measure the position of the moveable jaw relative to the stationary jaw.

In at least one embodiment of the present invention, there is provided an apparatus in which a sensor is integrated with the adjustment cylinder in order to detect the position of the moveable jaw. The detected position of the moveable jaw is compared with the actual position so as to adjust the CSS if necessary or desirable.

Typically, a jaw crusher will have two adjustment cylinders which control the position of respective wedges and which will be in communication with the sensor.

In addition, when in maintenance mode, the adjustment cylinders of at least one example of the apparatus in accordance with the present invention are drivable to urge the movable jaw against the stationary jaw to get a zero CSS position measurement. Measuring changes in the position at which the moveable jaw touches the stationary jaw provides an indication of wear. The adjustment cylinders are also provided with pressure sensors which are configured to detect physical contact between the moveable jaw and the stationary jaw which occurs at zero CSS.

These measurements can determine with high accuracy what the nominal CSS setting is, without the need for any external reference point. The sensors can also be calibrated to ensure accurate measurement over time.

The following figures show an example of a jaw crusher with a positioning device and sensor in accordance with the present invention. The jaw crusher and various components thereof are described across <FIG>.

With particular reference to <FIG> and <FIG>, the jaw crusher <NUM> comprises a movable jaw <NUM> and a stationary jaw <NUM> contained in a housing <NUM> and forming between them a variable crushing chamber <NUM> of the jaw crusher <NUM>. The movable jaw <NUM> is driven by an eccentric jaw crusher shaft <NUM> which causes the movable jaw <NUM> to move back and forth, up and down relative to the stationary jaw <NUM>.

The inertia required to crush material fed to the jaw crusher <NUM> is provided by a weighted flywheel <NUM> operable to move the eccentric jaw crusher shaft <NUM> on which the movable jaw <NUM> is mounted. A jaw crusher motor is operative for rotating the flywheel <NUM> by means of a transmission belt. The stationary jaw <NUM> is provided with a wear plate <NUM> and the movable jaw <NUM> is provided with a wear plate <NUM>. The movement of the eccentric shaft <NUM> thus causes an eccentric motion of the movable jaw <NUM>.

As shown in <FIG>, <FIG>, material to be crushed is fed to an intake <NUM> for material to be crushed. The crushed material leaves the jaw crusher <NUM> via an outlet <NUM> for material that has been crushed. The jaws <NUM>, <NUM> are farther apart at the material intake <NUM> than at the material outlet <NUM>, forming a tapered crushing chamber <NUM> so that the material is crushed progressively to smaller and smaller sizes as the material travels downward towards the outlet <NUM>, until the material is small enough to escape from the material outlet <NUM> at the bottom of the crushing chamber <NUM>.

With particular reference to <FIG>, <FIG>, <FIG> and <FIG>, the position of the moveable jaw <NUM> with respect to the stationary jaw <NUM> is set by an adjustment mechanism. The adjustment mechanism often referred to as a toggle system, is configured for setting or adjusting the spacing between the lower ends of the moveable jaw <NUM> and of the stationary jaw <NUM> so that a predetermined maximum product size may be produced during the crush cycle.

<FIG> is an isometric view of a toggle system for use in a jaw crusher in accordance with the present invention. In this embodiment the toggle system <NUM> comprises a toggle beam <NUM> which has a wedge <NUM> (see also <FIG>) configured to be moved by a drive cylinder <NUM> (see also <FIG>) in order to slide the wedge in and out in a transverse axis of the jaw crusher. The wedge <NUM> is moved by the hydraulic cylinder <NUM> to push a toggle beam <NUM> and thereby adjust the position of the moveable jaw <NUM> with respect to the stationary jaw <NUM>.

The hydraulic cylinder <NUM> is configured to move the wedge to increase or decrease its width thereby moving the toggle plate <NUM> (see also <FIG>) and thus the moveable jaw <NUM> towards the stationary jaw and so change spacing between the jaws <NUM>, <NUM> at the lower ends <NUM>, <NUM> respectively, <FIG> shows a wider gap between lower ends <NUM>, <NUM> and <FIG> shows a narrower gap.

Hydraulic cylinders <NUM> are configured to maintain pressure in the bore side of the cylinder to abut the toggle beam <NUM> to the wedge <NUM>. This abutment is critical during operation as it transfers crushing load from the moving jaw <NUM> to the surrounding structure. Furthermore hydraulic cylinders <NUM> have a direct relationship regarding position with cylinder <NUM>, meaning that the sensors <NUM> in <FIG>, can communicate with the PLC to control actuation of cylinder <NUM> to set the CSS.

Toggle clamping cylinder <NUM> maintains the pressure in the annulus side of the cylinder to clamp the toggle plate <NUM> (<FIG>) to ensure the crushing force is transmitted from the moveable jaw <NUM>.

<FIG> an isometric view of an adjustment device drive cylinder for use in a jaw crusher in accordance with the present invention.

The drive cylinder comprises a piston shaft <NUM> in a cylinder body <NUM> with a coupling <NUM>. Transducer <NUM> is mounted centrally in the cylinder body <NUM> and measures position of the moveable jaw, which is adjustable relative to the stationary jaw.

In this example of the present invention, and referring to <FIG>, the sensor <NUM> is mounted centrally in the cylinder <NUM> and comprises a linear displacement sensor which detects the cylinder rod/piston <NUM> position relative to the cylinder <NUM>. In this example of the present invention, the linear displacement sensor <NUM> is a magneto strictive linear position sensor suitable for use in extreme environments rugged steal housing. It comprises a magnet <NUM> mounted on piston shaft <NUM>, magnet position and hence stroke is detected with probe shaft <NUM>. The magnetostrictive sensor is exceptionally shock resistant, extremely waterproofness, an operational temperature range of -<NUM> to +<NUM> deg C, a pressure resistance rated up to <NUM> Bar, resolution to <NUM> micron and a suitable measurement length for the application.

The sensor <NUM> measures the cylinder extension/position and the signal from this sensor is used to derive the CSS via the machine programmable logic controller (PLC). The cylinder <NUM> position can also be set via the machine programmable logic controller PLC.

In addition to the linear displacement sensor <NUM>, a pressure sensor <NUM> (see <FIG>) is provided to detect external load on the moveable jaw. The pressure sensor is configured to detect contact between the moveable jaw and the stationary jaw. The pressure sensor assists with positioning of the moveable jaw with respect to the stationary jaw.

The cylinder <NUM> allows the moveable jaw to move through the entire range of CSS openings. Additionally, with the extra stroke length provided by the cylinder, additional wear measurement compensation is achieved. In this example, up to <NUM> of wear measurement compensation may be achieved.

<FIG> show a range of CSS positions which are achievable using the apparatus of the present invention.

<FIG> is a side cross section view of the maximum CSS distance between the fixed jaw and the moveable jaw of the jaw crusher. It shows a jaw crusher <NUM> as previously described above and in which the distance between the lower end <NUM> of the moveable jaw <NUM> and the lower end <NUM> of the stationary jaw <NUM> is at its maximum extent.

<FIG> is a side cross section view of the minimum CSS distance between the fixed jaw and the moveable jaw of the jaw crusher when the jaw crusher is in use. It shows a jaw crusher <NUM> as previously described above and in which the distance between the lower end <NUM> of the moveable jaw <NUM> and the lower end <NUM> of the stationary jaw <NUM> is at its minimum extent.

<FIG> is a side cross section view of the fixed jaw and the moveable jaw of the jaw crusher in accordance with the present invention in a fully closed position. It shows a jaw crusher <NUM> as previously described above and in which the lower end <NUM> of the moveable jaw <NUM> and the lower end <NUM> of the stationary jaw <NUM> overlap.

<FIG> is an isometric view of the toggle beam <NUM> and wedge <NUM> in contact in a jaw crusher in accordance with the present invention. It shows a jaw crusher <NUM> as previously described above along with the toggle plate <NUM>. As shown, the toggle beam <NUM> is in contact with the wedge <NUM> and crushing forces are transferred from the moveable jaw <NUM>.

<FIG> is an isometric view of the toggle beam <NUM> and wedge <NUM> not in contact in a jaw crusher in accordance with the present invention. It shows a jaw crusher <NUM> as previously described above along with the toggle plate <NUM>. As shown, the toggle beam <NUM> is not in contact with wedge <NUM>. This position allows wear measurement and CSS adjustment.

<FIG> is an isometric view of a control block <NUM> comprising a pressure sensor <NUM> in a jaw crusher in accordance with the present invention. When in maintenance/wear calibration mode, the adjustment cylinders are drivable to urge the movable jaw against the stationary jaw to get a zero CSS position measurement. Measuring changes in the position at which the moveable jaw touches the stationary jaw provides an indication of wear. The pressure sensor <NUM> is configured to detect physical contact between the moveable jaw and the stationary jaw which occurs at zero CSS.

<FIG> is a graph <NUM> which plots CSS setting <NUM> against cylinder stroke <NUM> and shows a family of curves <NUM> for wear values of <NUM> <NUM>, <NUM> <NUM>, <NUM> <NUM>, <NUM> <NUM>, <NUM> <NUM>, <NUM> <NUM> and <NUM> <NUM>. <FIG> provides an example of the type of calibration graph which may be used to calculate wear.

In another example of the present invention, a wear compensation sub routine is built into system logic in order to measure wear on the jaw wear plates. Wear of the plate, also referred to as a jaw liner, inherently increases the gap setting as material is removed from the crushing zone.

The amount of wear may be automatically determined by recording the position on one or each linear transducer when metal to metal contact has occurred (Zero CSS). The distance between the moveable jaw and the stationary jaw can be set to compensate for the wear in the jaw wear plates before the user specifies a final size of product.

Further to this, the logic is built so that the system can predict wear rates for the users specific application and automatically give the user updates as to when the wear liners need replacing or turning (Wear Prediction). The set points in the logic are directly related to the liner type selected within the PLC.

Wear calibration is conducted periodically, from this, each wear measurement will be stored within the machine PLC. Plotting this against crushing hours which is also stored will give a wear rate of liners within their current application. Using a few other parameters such as engine load/motor power consumption and product output (TPH), an estimation of the lifespan of the wear plates under predefined conditions may be obtained. The wear life given in time will be presented to the customer and allow them to order replacement liners at the correct time.

Claim 1:
A jaw crusher (<NUM>) comprising:
a crusher housing (<NUM>) having an inlet (<NUM>) for material to be crushed, an outlet (<NUM>) for material that has been crushed,
a moveable jaw (<NUM>), provided with a wear plate (<NUM>) and a stationary jaw (<NUM>), provided with a second wear plate (<NUM>), the moveable jaw (<NUM>) and the stationary jaw (<NUM>) forming between them a crushing chamber (<NUM>), the moveable jaw <NUM>) being coupled to an eccentric jaw crusher shaft (<NUM>) which causes the moveable jaw to reciprocate in an eccentric motion to crush the material between the moveable jaw (<NUM>) and the stationary jaw (<NUM>) and an adjustment device (<NUM>) for adjusting the position of the moveable jaw (<NUM>) relative to the stationary jaw (<NUM>), wherein the adjustment device (<NUM>) comprises one or more drive cylinder (<NUM>) with an internally mounted sensor (<NUM>) to measure the position of the moveable jaw (<NUM>) relative to the stationary jaw (<NUM>),
characterized in that the sensor (<NUM>) measures stroke distance of the drive cylinder,
wherein measurement of the stroke distance provides a measure of total wear on the moveable jaw wear plate (<NUM>) and fixed jaw wear plate (<NUM>),
wherein the crusher comprises a machine programmable logic controller (PLC) configured to perform wear calibration periodically and to store each wear measurement for determining wear rate of liners within their current application.