FIELD OF THE INVENTION

The present invention relates to a jaw crusher, more particularly, but not exclusively, to a jaw crusher for crushing rock material.

BACKGROUND OF THE INVENTION

Quarried material is often processed, by means of a crushing plant, for the production of aggregate, for example. There are various known forms of crushing plant for the comminution of rock material and the like, one of which is referred to as a jaw crusher.

One conventional jaw crusher is known as a single toggle or overhead eccentric jaw crusher. An alternative conventional jaw crusher is known as a double toggle jaw crusher. Both types of jaw crusher comprise a frame having side walls and a pair of jaws, a fixed jaw and a moveable jaw, disposed therebetween. The fixed jaw and the moveable jaw each have a crushing face, the crushing faces being arranged in a spaced apart relationship to define a crushing chamber for receiving material to be crushed.

In the single toggle or overhead eccentric jaw crusher, the upper end of the moveable jaw is connected to an eccentric shaft. In use, as the shaft is rotated, it is caused to prescribe a circle, which in turn causes the upper end of the moveable jaw to prescribe a circle in the direction of the fixed jaw. Hence, the crushing face of the moveable jaw moves in a crush cycle, up and down, as well as towards and away from the crushing face of the fixed jaw. Movement of the moveable jaw in this manner causes impelling forces for crushing material present in the crushing chamber.

Single toggle jaw crushers typically suffer from high wear of the crushing surfaces and are also typically unsuitable for the toughest applications.

In the double toggle jaw crusher, the upper end of the moveable jaw is pivotally fixed relative to the frame. A toggle plate is located behind the lower end of the moveable jaw. A first end of the toggle plate is coupled to the lower end of the moveable plate and a second end of the toggle plate is coupled to a pitman link, which is in turn connected to an eccentric shaft proximal the upper end of the moveable jaw. The second end of the toggle plate is also coupled to a second toggle plate which is fixed relative to the frame. In use, as the shaft is rotated, it is caused to prescribe a circle. This in turn causes the lower end of the moveable jaw to move towards and away from the fixed jaw, by virtue of the toggle plate and pitman link arrangement.

Double toggle jaw crushers typically have a poor capacity due to the minimal movement at the upper end of the moveable jaw.

The present invention seeks to overcome or at least mitigate / alleviate one or more problems associated with the prior art.

SUMMARY OF THE INVENTION

According to a first aspect of the present disclosure, a jaw crusher is provided comprising a frame, a fixed jaw and a moveable jaw, the frame and jaws defining a crushing chamber for receiving material to be crushed; the jaw crusher comprising a shaft configured for rotation with respect to the frame about an axis of rotation ; and the moveable jaw being mounted for cyclic movement in the direction of the fixed jaw via said shaft; wherein :

the moveable jaw comprises a free end which is coupled to the shaft via a coupling mechanism, the coupling mechanism comprising a first rotatable portion provided proximal the axis of rotation and configured for rotation about the axis of rotation .

In this way, the moveable jaw is mounted for cyclic movement in the direction of the fixed jaw via the shaft. In addition, the free end of the moveable jaw is coupled to the shaft via a coupling mechanism having a first rotatable portion which is configured to rotate about the axis of rotation. The motion of the first rotatable portion is therefore imparted to the free end of the moveable jaw by virtue of the coupling mechanism.

In other words, movement is imparted to the moveable jaw both by the jaw being mounted for cyclic movement via the shaft and also by the free end of the moveable jaw being coupled to the first rotatable portion, which is configured for rotation about the axis of rotation. The combined effect of this has been found to result in particularly advantageous movement of the moveable jaw, which improves the performance of the jaw crusher.

Advantageously, the motion conveyed to the moveable jaw can result in enhanced movement of the moveable jaw in a direction towards and away from the fixed jaw, along the length of the moveable jaw, and reduced movement in the direction perpendicular to this.

The increase in movement of the moveable jaw, along its length, in a direction towards and away from the fixed jaw results in increased impelling forces for crushing material in the crushing chamber, hence more effective crushing of material. This also results in increased throughput of material through the jaw crusher.

In exemplary embodiments, the fixed and moveable jaws each comprise a crushing face arranged to impact the material in the crushing chamber. The improvement in motion of the moveable jaw results in reduced wear of the crushing faces of the fixed and moveable jaws. Therefore, the crushing faces will require replacement less frequently, saving down time and cost.

The improved motion of the moveable jaw may permit a larger "nip angle" . The "nip angle" is the largest angle at which a lump of material can be "gripped" between the jaws. The performance of a jaw crusher is determined, at least in part, by its ability to "grip" the material being crushed. One factor which affects this performance is the "nip angle", this being the nominal included angle between the moveable and fixed jaws. It is desira ble to have the widest nip angle possible since this permits a smaller and lighter crusher for a given feed opening. The improved motion of the moveable jaw results in improved grip on the material being crushed. Consequently, a larger nip angle can be achieved, hence allowing the size and weight of the crusher to be reduced.

As described above, the first rotatable portion is configured for rotation about the axis of rotation. In other words, the rotatable portion is arranged to prescribe a circle about the axis of rotation.

Optionally, the moveable jaw is mounted for cyclic movement via a second rotatable portion configured for rotation about the axis of rotation.

Optionally, the first and second rotatable portions are configured such that rotation of the first rotatable portion is angularly offset from rotation of the second rotatable portion with respect to the axis of rotation.

In other words, rotation of the first rotatable portion is out of phase with rotation of the second rotatable portion. This has been found to be particularly adva ntageous in providing improved movement of the moveable jaw towards and away from the fixed jaw.

In exemplary embodiments, rotation of the first rotatable portion is angula rly offset from rotation of the second rotatable portion by about 60° to 150°, for example about 90° to 120°, or vice versa.

Optionally, rotation of the first rotatable portion about the axis of rotation is retarded compared to the second rotatable portion.

In other words, first rotatable portion follows the second rotatable portion, with respect to the direction of rotation, as it prescribes a circle about the axis of rotation.

In some embodiments, rotation of the second rotatable portion about the axis of rotation is retarded compared to the first rotatable portion.

Optionally, the first rotatable portion is configured to rotate about the axis of rotation to prescribe a first circle coaxial with the axis of rotation and having a first radius.

Optionally, the second rotatable portion is configured to rotate about the axis of rotation to prescribe a second circle coaxial with the axis of rotation and having a second radius. Optionally, the first radius and the second radius have different values.

In this way, the first rotatable portion and the second rotatable portion are arranged to prescribe circles about the axis of rotation having different radii. This has been found to be particula rly advantageous in providing improved movement of the moveable jaw.

In exemplary embodiments, the first radius is larger than the second radius, e.g . 5- 10mm larger, or vice versa .

In exemplary embodiments, the first radius is 2-30mm, for example: 5-25mm, 10- 20mm, 12-18mm, 15-25mm, 17-23mm, 20-30mm, or 22-28mm.

In exemplary embodiments, the second radius is 2-30mm, for example: 5-25mm, 10- 20mm, 12-18mm, 15-25mm, 17-23mm, 20-30mm, or 22-28mm.

In exemplary embodiments, the second radius is 12- 18mm and the first radius is 5- 10mm larger. In exemplary embodiments, the second radius is larger than the first radius.

In exemplary embodiments, the first and second radius have the same value.

Optionally, the first circle is prescribed by a geometric centre of the first rotatable portion or by a location via which the first rotatable portion is coupled to the free end.

In this way, the geometric centre of the first rotatable portion is offset from the axis of rotation by a d istance equal to the first radius. This can be thought of as a first offset amount.

Optionally, the second circle is prescribed by a geometric centre of the second rotatable portion .

In this way, the geometric centre of the second rotatable portion is offset from the axis of rotation by a distance equal to the second radius. This can be thought of as a second offset amount.

Optionally, the moveable jaw comprises a mounted end, spaced a part from the free end, wherein the mounted end is mounted for cyclic movement in the direction of the fixed jaw via said shaft.

In exemplary embodiments, the mounted end of the moveable jaw is a proximal end provided proximal the axis of rotation. In exemplary embodiments, the free end of the moveable jaw is a dista l end provided dista l the axis of rotation .

Optionally, the first rotatable portion of the coupling mechanism comprises a first eccentric component configured for eccentric rotation about the axis of rotation.

Optionally, the first eccentric component comprises a circula r cross section, arranged such that the centre of the circular cross section is radially offset from the axis of rotation by a first offset amount.

In some embodiments, the centre of the circular cross section prescribes the first circle as it rotates, the first radius of the first circle equating to the first offset amount.

Optionally, the coupling mechanism comprises a linking arrangement which is mounted on the first eccentric component, for example via a bearing . The eccentric motion of the first eccentric component imparts movement to the free end of the moveable jaw, via the linking arrangement. The effect of this, together with the motion of the second rotatable portion, has been found to result in pa rticularly advantageous movement of the moveable jaw, which improves the performance of the jaw crusher.

In other words, by way of the linking arrangement, the eccentric movement of the first eccentric component is translated in to movement of the moveable jaw.

Optionally, the first eccentric component comprises a disc fixed for rotation with the shaft.

In exemplary embodiments, the first eccentric component is integrally formed with the shaft. In exempla ry embodiments, the first eccentric component and the shaft comprise separate components, wherein the first eccentric component is fixed for rotation with the shaft. In exempla ry embodiments, the first eccentric component comprises an eccentric disc (e.g. fixed for rotation with the shaft), an eccentric portion of the shaft, and/or other suitable component.

In exemplary embodiments, the first eccentric component comprises an eccentric portion of the shaft.

Optionally, the second rotatable portion comprises a second eccentric component configured for eccentric rotation a bout the axis of rotation.

Optionally, the second eccentric component comprises a circular cross section, arranged such that the centre of the circular cross section is radially offset from the axis of rotation by a second offset amount.

In exemplary embodiments, the moveable jaw is mounted on the second rotatable portion (e.g . the second eccentric component), for example, via a bearing. In this way, the eccentric movement of the second rotatable portion is imparted directly to the mounted end of the moveable jaw.

Optionally, the or a first offset amount and the second offset amount are different amounts. This has been found to be particularly adva ntageous in providing improved movement of the moveable jaw towards and away from the fixed jaw.

In exemplary embodiments, the first offset amount is larger than the second offset amount, e.g. 5-10mm larger, or vice versa.

In exemplary embodiments, the first offset amount is 2-30mm, for example: 5-25mm, 10-20mm, 12-18mm, 15-25mm, 17-23mm, 20-30mm, or 22-28mm.

In exemplary embodiments, the second offset amount is 2-30mm, for example : 5- 25mm, 10-20mm, 12- 18mm, 15-25mm, 17-23mm, 20-30mm, or 22-28mm.

In exemplary embodiments, the second offset amount is 12-18mm and the first offset amount is 5-10mm larger.

In exemplary embodiments, the second offset amount is larger than the first offset amount.

In some embodiments, the first and second offset amount are the same amount.

Optionally, the or a centre of the or a circular cross section of the first eccentric component is angularly offset from the centre of the circular cross section of the second eccentric component with respect to the axis of rotation.

In other words, the centre points of the first and second eccentric components are angularly offset from each other with respect to the axis of rotation. This has been found to be particularly advantageous in providing improved movement of the moveable jaw towards and away from the fixed jaw.

Optionally, the second eccentric component is integrally formed with the shaft.

In this way, a more simple jaw crusher arrangement is provided with a reduced number of parts. This is simpler to manufacture and is likely to reduce the required maintenance and repair of the jaw crusher.

In exemplary embodiments, the second eccentric component comprises an eccentric portion of the shaft and the first eccentric component comprises an eccentric disc (e.g . fixed for rotation with the shaft), or vice versa. In exemplary embodiments, the second eccentric component and the shaft comprise separate components, wherein the second eccentric component is fixed for rotation with the shaft. For example, the second eccentric component comprises an eccentric disc (e.g . fixed for rotation with the shaft), an eccentric portion of the shaft, and/or other suitable component.

Optionally, the first rotata ble portion of the coupling mechanism comprises: a cam mounted on the shaft, a crank mounted on the shaft, or a portion of the shaft itself.

Optionally, the coupling mechanism a lso comprises a linking arrangement which is coupled to the first rotatable portion at a position radially offset from the axis of rotation by a first offset amount.

It will be appreciated that the location at which the linking arrangement is coupled to the shaft (e.g . via the cam or crank) can notionally be thought of as being equivalent to centre of a circular cross section of an eccentric disc or component as previously described. As will be understood by the skilled person, any coupling mechanism which performs an equivalent function can be used.

Optionally, the second rotatable portion comprises an eccentric component configured for eccentric rotation about the axis of rotation.

Optionally, the eccentric component comprises a circular cross section, arranged such that the centre of the circular cross section is radially offset from the axis of rotation by a second offset amount.

In exemplary embodiments, the centre of the circular cross section prescribes the second circle as it rotates, the second radius of the circle equating the second offset amount.

Optionally, the or a first offset amount and the second offset amount a re different amounts.

This has been found to be particularly adva ntageous in providing improved movement of the moveable jaw towards and away from the fixed jaw. In exemplary embodiments, the first offset amount is larger than the second offset amount, e.g. 5-10mm larger, or vice versa.

In exemplary embodiments, the first offset amount is 2-30mm, for example: 5-25mm, 10-20mm, 12-18mm, 15-25mm, 17-23mm, 20-30mm, or 22-28mm.

In exemplary embodiments, the second offset amount is 2-30mm, for example : 5- 25mm, 10-20mm, 12- 18mm, 15-25mm, 17-23mm, 20-30mm, or 22-28mm.

In exemplary embodiments, the second offset amount is 12-18mm and the first offset amount is 5-10mm larger.

In exemplary embodiments, the second offset amount is larger tha n the first offset amount.

In some embodiments, the first and second offset amounts are the same amount.

Optionally, the or a position at which the or a linking arra ngement is coupled to the first rotatable portion is angularly offset from the centre of the circular cross section of the eccentric component with respect to the axis of rotation.

In other words, position at which the first rotatable portion is coupled to the linking arrangement is angularly offset from the centre point of the eccentric component (i .e. the second rotatable portion) with respect to the axis of rotation. This has been found to be particula rly advantageous in providing improved movement of the moveable jaw towards and away from the fixed jaw.

Optionally, the eccentric component is integrally formed with the shaft.

Optionally, the coupling mechanism is configured to couple the free end of the moveable jaw to a fixed location with respect to the frame, optionally wherein the jaw crusher comprises an adjustment mechanism which is configured to adjust the position of the fixed location with respect to the frame.

In this way, the motion of the coupling mechanism is somewhat constrained . This is advantageous in translating the movement of the first rotatable component (e.g .

rotational or eccentric movement about the shaft) into movement of the free end of the moveable jaw. By coupling the free end of the moveable jaw to a fixed location with respect to the frame, e.g. by the linking mechanism, a desired spacing between the moveable jaw and the fixed jaw can be set. For example, a desired spacing between the lower ends of the jaws, i.e. where the crushed material is discharged during the crushing cycle, can be set. By setting the spacing between the pair of jaws in this way, a predetermined maximum product size is produced during the crushing cycle. It will be understood that larger pieces of crushed material are produced using a greater jaw spacing than would be produced by using a smaller jaw spacing .

By adjusting the position of the fixed location, the spacing between the pair of crushing jaws can also be adj usted. Accordingly, the spacing of the jaws can be set to produce a desired size of crushed material .

In exemplary embodiments, the adj ustment mechanism comprises a hydraulic cylinder arrangement.

In exemplary embodiments, the frame includes a pair of walls, between which the fixed jaw and moveable jaw are disposed . In exemplary embodiments, the adjustment mechanism comprises a pair of hydraulic cylinders, one cylinder being arranged on either side of the frame, e.g . with a longitudinal axis of each cylinder being in the same plane as a respective wall.

In exemplary embodiments, the frame provides a reaction to the action of the hydraulic cylinder arrangement.

In exemplary embodiments, the adj ustment mechanism comprises one or more shims, one or more wedges, or other suitable adj ustment means to reduce or increase the spacing between the jaws.

Optionally, the coupling mechanism comprises the or a linking arrangement, the linking arrangement comprising a release mecha nism configured to actuate when a force applied to the coupling mechanism by the moveable jaw exceeds a predetermined amount, and wherein actuation of the release mechanism reduces the force applied to the coupling mechanism.

If an uncrushable object enters the crushing chamber, substantial forces are generated as the moveable jaw acts to complete its cyclic motion against the uncrushable object. The generation of these forces can cause damage to the jaw crusher. In some cases, the forces generated cause the coupling mechanism to give way, which renders the jaw crusher inoperative until the coupling mechanism, or at least the damaged part of the coupling mechanism, is replaced, therefore affecting productivity.

In exemplary embodiments wherein the linking arrangement comprises a release mechanism, when the forces generated by the moveable jaw exceed a predetermined amount, the release mechanism is actuated. Such actuation modifies the geometry of the coupling mechanism such that the forces on the coupling mechanism are reduced. In exemplary embodiments, actuation of the release mechanism causes the spacing between the fixed jaw and moveable jaw to be increased, thereby releasing the uncrushable object from the crushing chamber and reducing the forces exerted on the coupling mechanism.

In this way, the release mechanism acts to protect the coupling mechanism against damage resulting from an uncrushable object entering the crushing chamber.

In exemplary embodiments, the release mechanism is configured to actuate when a predetermined force of between 300 and 500 bar is reached.

By providing the release mechanism as part of the linking arrangement, advantageously the release mechanism is only exposed to a small amount of the direct crushing force of the moveable jaw.

In exemplary embodiments, the release mechanism comprises a hydraulic cylinder arrangement.

In exemplary embodiments, the release mechanism may comprise a spring loaded ball/detent system, a "weak link" failure device, or any other suitable arrangement.

In exemplary embodiments, the adjustment mechanism and the release mechanism are provided by the same mechanism. In this way, a simple arrangement having a reduced number of components is provided.

Optionally, the coupling mechanism comprises a stop mechanism configured to limit actuation of the release mechanism beyond a predetermined amount. Optionally, the stop mechanism comprises two or more components configured to abut each other when the release mecha nism reaches the predetermined amount of actuation.

In some embodiments, as the release mechanism is actuated, e.g . extended, the two or more components of the stop mechanism are brought towards each other, such that, when the release mechanism reaches a predetermined level or amount of actuation, the components abut one another. When the components abut each other, further actuation of the release mechanism is prevented.

Advantageously, the configuration of the stop mechanism is such that over actuation of the release mechanism is prevented. For example, when the release mechanism comprises a hydra ulic cylinder, the cylinder is configured to extend when the

predetermined force is a pplied to the coupling mechanism. When the hydraulic cylinder reaches a predetermined amount of extension, the components of the stop mechanism are configured to abut one another, thereby preventing further extension of the hydraulic cylinder. In this way, the hydraulic cylinder is protected against damage caused by over-extension.

Advantageously, by providing two or more components configured to abut each other when the release mechanism reaches a predetermined level of actuation, a simple, mechanical means for protecting the release mechanism is provided .

Optionally, the coupling mechanism comprises the or a linking arrangement, and wherein the linking arrangement comprises an articulated arrangement having two or more components connected via a joint.

Such an articulated arrangement translates the motion of the first rotatable portion of the coupling mechanism about the axis of rotation into movement at the free end of the moveable jaw.

Optionally, the articulated arrangement comprises a pitman link coupled to the shaft, and a first toggle link which is coupled to the free end of the moveable jaw, wherein the pitman link and the first toggle link are coupled together at the joint. Optionally, the pitman link and the first toggle link are coupled to the or a fixed location, with respect to the frame, via a second toggle link, wherein the second toggle link is coupled to the pitman link and the first toggle link at the joint. Advantageously, the pitman link is arranged to translate the rotational motion of the first rotatable portion, into substantially linear or reciprocal motion at the joint.

In exemplary embodiments, the pitman link is coupled to the shaft directly, via the first eccentric component, via a ca m or crank arrangement, or via another suitable arrangement.

In exemplary embodiments, the coupling mechanism comprises a single pitman link. In some embodiments, a pair of linking mechanisms are provided, e.g. at either end of the shaft, which are coupled to the first toggle link e.g. a first toggle plate.

In exemplary embodiments, the second toggle link is a toggle plate coupled to a pair of pitman links.

In exemplary embodiments, the first and second toggle links locate in seats in the lower end of the pitman link and are retained in place via tension in the coupling mechanism.

In exemplary embodiments, a first end of the first toggle link is pivotally connected (e.g . directly connected) to the moveable jaw e.g . to a rear of the moveable jaw. In exemplary embodiments, a second end of the first toggle link is pivotally connected (e.g. directly connected) to the pitman link at the joint.

In exemplary embodiments, a first end of the second toggle link is pivotally connected (e.g . directly connected) to the pitman link and the second end of the first toggle link at the joint. In exemplary embodiments, a second end of the second toggle link is pivotally connected (e.g . directly connected) to the fixed location.

In exemplary embodiments, the second toggle link is coupled to the adjustment mechanism. Advantageously, the spacing between the fixed jaw and the moveable jaw can be adjusted by the adjustment mechanism, via the toggle link linkage between the adjustment mecha nism and the moveable jaw. This provides a simple means for adjusting the jaw spacing.

In exemplary embodiments the pitman link comprises a fixed length.

Optionally, the pitman link comprises the or a release mechanism, which is configured to actuate when a force applied to the coupling mechanism by the moveable jaw exceeds a predetermined amount, wherein actuation of the release mechanism comprises extension or retraction of the pitman link to reduce the force applied to the coupling mechanism.

As described above, provision of such a release mechanism acts to prevent damage to the jaw crusher when an uncrushable object enters the crushing chamber.

In exemplary embodiments, the release mechanism is opera ble to extend or reduce the length of the pitman link when a predetermined force generated by the moveable jaw is exceeded. In exemplary embodiments, the pitman link comprises a hydraulic cylinder configured to extend or retract when the forces generated by the moveable jaw exceed the predetermined amount.

Optionally, the first togg le link and the second toggle link a re coupled to the pitman link such that the toggle links are configured to form the or a stop mechanism, wherein the first and second toggle links are configured to abut one another when the release mechanism reaches a predetermined amount of actuation, e.g . a predetermined a mount of extension.

In this way, actuation (for example, extension or retraction) of the release mechanism is limited to a maximum (or minimum) amount, due to the configuration of the toggle links. Advantageously, over-extension of the release mecha nism is therefore prevented, reducing the risk of damage to the release mechanism. Similarly, over- retraction of the release mechanism may be prevented, reducing the risk of excessive strain being applied to the linking mechanism (e.g . to the joint between the pitman link and the toggle link(s)) .

Further, over-extension of the release mechanism can result in high forces being applied to the release mechanism due to the geometry of the pitman link and toggle links. In exemplary embodiments, for a given crushing force, the force in the pitman link will increase as the included angle between the toggle links reduces (i .e. as the release mechanism extends). The stop mechanism acts to prevent such over-extension and hence prevent high forces being a pplied to the release mechanism.

Optionally, the stop mechanism is configured such that an included angle formed between the toggle links remains greater than a predetermined angle, and wherein the first and second toggle links are configured to abut each other when the included angle between the toggle links reaches the predetermined angle. In this way, the geometry of the coupling arrangement is restricted to ensure that the included angle between the toggle links remains greater than a predetermined angle. If the angle between the toggle links was to become too small, this may put pressure on the joint between the toggle links and pitman link, and potentially result in damage to the coupling arrangement.

In exemplary embodiments, the included angle is between 45° and 180°, for example between 90° and 180°, for example between 110° and 160°, for example between 110° and 130°, for example between 130° and 150°.

This arrangement is particularly advantageous when the pitman link comprises the release mechanism, which is operable to extend or retract the length of the pitman link when a predetermined force generated by the moveable jaw is exceeded. In such an embodiment, extension or retraction of the release mechanism results in a change in the included angle between the toggle plates. Therefore, by imposing a predetermined lower limit on this included angle, the extension or retraction of the release mechanism is limited to a maximum amount. Advantageously, over-extension of the release mechanism is thereby prevented, reducing the risk of damage to the release mechanism.

In exemplary embodiments, the configuration of the toggle links ensures that the angle between the pitman link and the first and/or second toggle links remains sufficiently large to prevent or reduce the risk of damage to the coupling arrangement and/or the release mechanism. Therefore, a coupling arrangement geometry providing a reduced risk of damage to the jaw crusher is maintained.

It will be appreciated that the optional features described above and herein may be applicable to any aspect of the disclosure. All combinations contemplated will not be explicitly recited here for the sake of brevity.

BRIEF DESCRIPTION OF THE DRAWINGS

Embodiments of the invention will now be described with reference to the accompanying drawings, in which :

Figure 1 is a cross section view of a first embodiment of a jaw crusher disclosed herein;

Figure 2 is a schematic diagram of the jaw crusher of Figure 1; Figure 3 is a cross section view of the jaw crusher of Figure 1 taken along the length of the shaft of the jaw crusher;

Figure 4 is a close up view of the cross section of Figure 3;

Figures 5a to 5d are schematic illustrations of the motion of the jaw crusher of Figure 1 as it moves through a complete crushing cycle;

Figure 6 is a cross section view of a second embodiment of a jaw crusher disclosed herein;

Figure 7 is a cross section view of the jaw crusher of Figure 6 in which the release mechanism is in its extended configuration;

Figure 8 is a cross section view of a third embodiment of a jaw crusher disclosed herein; and

Figure 9 is a cross section view of a portion of a fourth embodiment of a jaw crusher disclosed herein.

DETAILED DESCRIPTION OF EMBODIMENT(S)

Referring to Figures 1 to 3, a jaw crusher is indicated generally at 2 and includes a frame 4 having a fixed jaw 6 and a moveable jaw 8. The frame 4 and the jaws 6, 8 define a crushing chamber 10 into which material to be crushed is fed.

Material to be crushed enters the crushing chamber 10 at opening 10a, and leaves the crushing chamber 10 at dispensing aperture 10b.

The jaw crusher 2 includes a shaft 12 which is arranged to rotate about an axis of rotation A.

The moveable jaw 8 includes a mounted end 8a and a free end 8b distal the shaft 12. In the illustrated embodiment, the mounted end 8a is provided towards an upper end of the moveable jaw 8 and the free end 8b is provided towards a lower end of the moveable jaw 8.

The movable jaw 8 is mounted for cyclic movement in the direction of the fixed jaw 6 via the shaft 12.

The free end 8b of the moveable jaw 8 is coupled to the shaft 12 via a coupling mechanism 16. The coupling mechanism 16 includes a first rotata ble portion 16a provided proximal the axis of rotation 4 and configured for rotation about the axis of rotation A.

The moveable jaw 8 is mounted for cyclic movement via a second rotatable portion 14, wherein the second rotata ble portion 14 is configured for rotation about the axis of rotation A.

The first and second rotatable portions 16a, 14 are arranged such that rotation of the first rotatable portion 16a and rotation of the second rotatable portion 14 about the axis of rotation A imparts movement to the moveable jaw 8.

As is illustrated in Figure 2, the first and second rotatable portions 16a, 14 are configured for rotation such that rotation of the first rotatable portion 16a is angularly offset from rotation of the second rotatable portion 14, with respect to the axis of rotation A.

In Figure 2, the angular displacement between the first rotatable portion 16a and the second rotatable portion 14 is indicated by reference numera l B. In the illustrated embodiment, rotation of the first rotatable portion 16a is arranged to follow that of the second rotatable portion 14 with respect to the direction of rotation C. For example, rotation of the first rotatable portion 16a is retarded compared to the second rotatable portion 14 by about 90° to 120°. As is most clearly seen in Figure 4, rotation of the first rotatable portion 16a is radially offset with respect to the axis of rotation A by a first offset amount P. Rotation of the second rotatable portion 14 is coupled to the shaft 12 such that rotation of the second rotatable portion 14 is radially offset from the axis of rotation A by a second offset amount J . In exemplary embodiments, the second offset amount J is about 12-18mm and the first offset amount P is about 5- 10mm larger. In the embodiment illustrated in Figure 4, the second offset amount J is larger than the first offset amount P.

As will be appreciated from the following description, the first rotatable portion 16a and the second rotatable portion 14 are coupled to the shaft 12 such that the first and second rotatable portions 16a, 14 is radially off-centre to the axis of rotation A.

Referring to Figure 3, the first rotatable portion 16a includes a first eccentric component 24 in the form of an eccentric disc which is fixed for rotation with the shaft 12. The eccentric disc 24 comprises a circular cross section having a centre 26 which is radially offset from the axis of rotation A by the first offset amount P (see Figure 2) .

It will be understood that the embodiment illustrated in Figure 3 includes a pair of first eccentric components 24 in the form of a pair of eccentric discs. In exemplary embodiments, a single first eccentric component is provided . In exemplary

embodiments, more than two first eccentric components are provided, for example, 3, 4, 5, or 6 first eccentric components.

The coupling mechanism 16 also includes a linking arrangement 28 which couples the eccentric discs 24 to the free end 8b of the moveable jaw 8. As can be seen from Figure 3, the eccentric discs 24 are mounted on the shaft 12. The linking arrangement 28 is then mounted on the eccentric discs 24 via bearings 30.

The second rotatable portion 14 includes a second eccentric component 18 which is arranged for eccentric rotation about the axis of rotation A. The second eccentric component 18 has a circular cross section with a centre point 20 which is radially offset from the axis of rotation A by the second offset amount J . This is shown in Figure 2. As can be seen in Figure 3, the second eccentric component 18 is integrally formed with the shaft 12 and the mounted end 8a of the moveable jaw 8 is mounted on the second eccentric component 18 (i .e. the eccentric portion of the shaft 12) via bearings 22.

It will be understood that the embodiment illustrated in Figure 3 includes a pair of second eccentric components 18 in the form of a pair of eccentric portions of the shaft 12. In exemplary embodiments, a single second eccentric component is provided. In exemplary embodiments, more than two second eccentric components are provided, for example, 3, 4, 5, or 6 second eccentric components.

With reference to Figure 2, the centre 20 of the circular cross section of the eccentric portions of the shaft 18 (i.e. the second eccentric components) and the centre 26 of the eccentric d iscs 24 (i.e. the first eccentric components) are angularly offset from each other by angular displacement B, with respect to the axis of rotation A. As previously described, the angular displacement B is about 90° to 120° in the illustrated

embodiment.

As can be most clearly seen in Figure 4, the centre point 26 of the eccentric discs 24 (i .e. the first eccentric components) is radially offset from the axis of rotation A by the first offset amount P. The centre point 20 of the eccentric portions of the shaft 18 (i.e. the second eccentric components) is radially offset from the axis of rotation A by the second offset amount J . The first offset amount P and the second offset amount J are different amounts. In exemplary embodiments, the second offset amount 3 is about 12-18mm and the first offset amount P is about 5- 10mm larger. In the embodiment illustrated in Figure 4, the second offset amount J is larger than the first offset amount P.

In other words, the eccentric discs 24 (i.e. the first rotatable portion 16a) are configured to rotate about the axis of rotation A such that the centre 26 of the discs 24 prescribes a first circle coaxial with the axis of rotation A and having a first radius P. It will be understood that the first radius equates to the first offset amount P.

The eccentric portions 18 of the shaft (i.e. the second rotatable portion 14) are configured to rotate about the axis of rotation A such that the centre 20 of the circular cross section of the eccentric shaft portions 18 prescribes a second circle coaxial with the axis of rotation A and having a second radius J. It will be understood that the second radius equates to the second offset amount P. Therefore, the first radius P and the second radius J have different values. In some exempla ry embodiments, the first radius P and the second radius J have the same value.

Referring now to Figure 1, the coupling mechanism 16, in particular the linking arrangement 28 of the coupling mechanism 16, is arranged to couple the free end 8b of the moveable jaw 8 to a fixed location 32 with respect to the frame 4. The jaw crusher 2 includes an adjustment mechanism 34 which is configured to adjust the position of the fixed location 32 with respect to the frame 4. In the illustrated embodiment, the adjustment mechanism 34 includes a hydraulic cylinder a rrangement in which extension and retraction of the hydraulic cylinder adjusts the position of the fixed location 32 by adjusting the position of wedges 32a . In alternative embodiments, the wedges 32a may be adjusted manua lly. In exemplary embodiments, the fixed location 32 is adjusted directly by hydraulic cylinders. In exemplary embodiments, the hydraulic cylinder arrangement may comprise 1, 2, 3, 4, 5, or 6 hydraulic cylinders.

The linking arra ngement 28 of the coupling mechanism 16 is formed of an articulated arrangement including a pair of pitman links 36, which are mounted on the eccentric discs 24 (see Figure 3). The linking arrangement 28 a lso includes first toggle plate 38 and second toggle plate 40. It will be appreciated, with reference to Figure 3, that a pitman link 36 is provided at both ends of the shaft 12 a nd that both of these pitman links are coupled to the first and second toggle plates 38 and 40, the toggle plates 38, 40 extending between the two pitman links 36.

In exemplary embodiments, a single pitman link is provided. In exemplary

embodiments, more than two pitman links are provided, for example, 3, 4, 5, or 6 pitman links.

The first toggle plate 38 is pivotally coupled at one end to the pitman links 36 and pivotally coupled at its other end to the free end 8b of the moveable jaw 8. The second toggle plate 40 is pivota lly coupled at one end to the pitman links 36 and at the other end to the adjustment mechanism 34. Specifically the second toggle plate 40 rests in a toggle seat provided at the fixed location 32. The toggle seat sits against wedges 32a which can be moved for toggle seat adjustment, i.e. adjustment of the fixed location 32 In this way, the second toggle plate is coupled to the fixed location 32 with respect to the frame 4 of the jaw crusher 2. It will therefore be appreciated that the coupling mechanism 16 is coupled to the jaw crusher at three points, the shaft 12, the free end 8b of the moveable jaw 8 and the fixed position 32.

In use, the shaft 12 of the jaw crusher 2 rotates about the axis of rotation A, consequently the first rotatable portion 16a and the second rotatable portion 14 rotate about the axis of rotation A. In other words, the first rotatable portion 16a and the second rotatable portion 14 are caused to prescribe a circle, about the axis of rotation A, as the shaft 12 is rotated . The eccentric portions 18 of the shaft 12, forming the second eccentric components 18, rotate eccentrically a bout the axis of rotation A. Since the mounted end 8a of the moveable jaw is mounted on the eccentric portions of the shaft 18, this eccentric rotation is translated to movement at the mounted end 8a of the moveable jaw 8.

As the shaft 12 rotates about the axis of rotation A the eccentric discs 24 rotate eccentrically about the axis of rotation A. The pitman links 36 a re mounted on the eccentric discs 24 by bearings 30 and so this eccentric movement is translated to the pitman links 36, which in turn causes reciproca l movement at the opposite end of the pitman links 36, i.e. the end coupled to the first and second toggle plates 38, 40. By virtue of this linking arrangement 28 the eccentric rotation of the eccentric discs 24 is translated into movement at the free end 8b at the moveable jaw 8.

The resulting overa ll movement of the moveable jaw 8 is illustrated in Figures 5a-5d, which illustrate the position of the moveable jaw as the shaft completes a single revolution about the axis of rotation A. It will be appreciated that the particular motion may vary depending on the geometry of the jaw crusher and the particular para meters selected .

It has been found that the resulting movement of the moveable jaw 8 is improved compared to that of known jaw crushers. In particular the movement of the moveable jaw 8 towards and away from the fixed jaw 6 is maximised and vertical motion (i .e. perpendicular to the direction of motion towards and away from the fixed jaw) is minimised, as compared with single toggle jaw crushers. In this way, movement of the moveable jaw 8 in a direction towards and away from the fixed jaw 6, along the length of the moveable jaw 8, is enhanced . This results in increased impelling forces for crushing material in the crushing chamber 10.

As can be seen in Figure 1, the jaws include removable crushing faces. The fixed jaw 6 includes a crushing face 42 and the moveable jaw 8 includes a crushing face 44. The improved motion of the moveable jaw 8 as described above results in reduced wear of the crushing faces 42, 44 of the jaws. Consequently the crushing faces 42, 44 will require replacement less frequently, saving downtime and cost.

Also, the improved motion of the moveable jaw 8 may permit a larger nip a ngle to be achieved . This allows the size and weight of the crusher 2 to be reduced.

It will be appreciated that by coupling the free end 8b of the moveable jaw 8 to a fixed location 32 with respect to the frame 4, a desired spacing between the moveable jaw 8 and the fixed jaw 6 can be set. In particular, a desired spacing between the lower ends of the jaws, i.e. where the crush material is discharged during the crushing cycle, can be set. This means that a predetermined maximum product size will be produced during the crushing cycle. It will be understood that larger pieces of crushed material are produced using a greater jaw spacing than would be produced by using a smaller jaw spacing.

Accordingly, by actuating the adjustment mechanism 34, the position of the fixed location 32 and consequently the spacing between the pair of crushing jaws 6, 8 can be adjusted. For example, by extending the hydraulic cylinder arrangement of the adjustment mechanism 34, the spacing between the pair of crushing jaws 6, 8 can be reduced . Conversely, by retracting the hydraulic cylinder arra ngement of the adjustment mechanism 34, the spacing between the pair of crushing jaws 6, 8 can be increased .

A second embodiment of the jaw crusher disclosed herein is illustrated in Figures 6 and 7. In the figures, like features are denoted by the same reference numerals as for the first embodiment illustrated in Figures 1-5. For the sake of brevity, only the features which are different to those of the first embodiment will be described in deta il. With reference to Figure 6, the pitman links 36 comprise a release mechanism 46. The release mechanism 46 is configured to actuate when a force applied to the coupling mechanism 16 by the moveable jaw 8 exceeds a predetermined amount. Actuation of the release mechanism 46 acts to reduce the force applied to the coupling mechanism 16.

In the illustrated embodiments, the release mechanism 46 comprises a hydraulic cylinder arrangement. This is arranged to extend or retract, depending on the particular geometry of the jaw crusher and the linking mechanism, when the force applied to the coupling mechanism 16 exceeds the predetermined force. In exemplary embodiments, the predetermined force may be between 300 and 500 bar.

If an uncrushable object 48 enters the crushing chamber 10, substantial forces are generated as the moveable jaw 8 acts to complete its motion through the crushing cycle against the uncrushable object. The forces generated as a result of this may impact the coupling mechanism 16 and, in some cases, cause the coupling mechanism 16 to give way, rendering the jaw crusher inoperative until the coupling mechanism 16, or at least the damaged part, is replaced. This affects productivity as well as requiring repair of the jaw crusher.

In the embodiment of Figures 6 and 7 when the forces generated by the moveable jaw 8 exceed the predetermined amount, the release mechanism is actuated to extend the length of the pitman link 36. In other words the hydraulic cylinder arrangement of the release mechanism 46 is extended. As can be seen in Figure 7, actuation of the release mechanism in this manner causes the spacing between the fixed jaw 6 and the moveable jaw 8 to be increased. This releases the uncrushable object from the crushing chamber 10 and reduces the forces exerted on the coupling mechanism 16.

In this way, the release mechanism 46 acts to protect the coupling mechanism 16 against damage.

Further, since the release mechanism 46 is provided as part of the pitman link 36, the release mechanism 46 is only exposed to a small amount of the direct crushing force of the moveable jaw 8. It will be appreciated that for some geometries of the linking arrangement 28, actuation of the release mechanism 46 will involve retraction of the hydraulic cylinder

arrangement.

With reference to Figure 8, a third embodiment of the jaw crusher 2 disclosed herein is illustrated . Again, like parts are denoted by the same numerals as detailed for embodiments 1 and 2 above. For the sake of brevity, only features which differ from the embodiments discussed above will be described .

In the embodiment illustrated in Figure 8, the coupling mecha nism 16 includes a stop mechanism 50 which is configured to limit actuation of the release mechanism 46 (not shown in Figure 8) beyond a predetermined amount. The stop mechanism 50 includes two components which are configured to abut each other when the release mechanism 46 reaches the predetermined amount of actuation.

The first toggle plate 38 comprises a first abutment 52 and the second toggle plate 40 includes a second abutment 54. The first and second abutments 52, 54 are arranged to abut one another when the release mechanism 46 reaches a predetermined degree of actuation, for example a predetermined amount of extension or retraction.

Consequently, actuation of the release mechanism 46 is limited to a predetermined amount. For example, over extension of the release mechanism 46 is prevented in this manner, which reduces the risk of damage to the release mechanism.

As can be seen from Figure 8, the stop mechanism 50 is arranged such that an included angle formed between the first and second toggle plates 38, 40 remains greater than a predetermined angle during a complete revolution of the shaft 12 and/or actuation of the release mechanism 46. The first abutment 52 and the second abutment 54 are arranged to abut each other when the included a ngle between the toggle plates 38, 40 reaches the respective predetermined angle.

Over extension of the release mechanism 46 can cause damage to the release mechanism. Similarly over retraction of the release mechanism 46 may result in excessive strain being applied to the linking arrangement 28. In addition to this, over extension of the release mechanism 46 ca n result in high forces being applied to the release mechanism 46 due to the geometry of the pitman link and the toggle plates and the crushing action of the jaw.

In exemplary embodiments, the release mechanism 46 may be extended, for example when an uncrusha ble object 48 enters the crushing chamber 10. Extension of the release mechanism in the illustrated embodiment will act to reduce the included angle between the first and second toggle plates 38, 40. When the included angle is decreased to the extent that it reaches a predetermined angle, the first and second abutments 52, 54 are brought into contact with each other to prevent further reduction of the included angle.

In this way, the release mechanism is protected . It will be appreciated that the abutments 52, 54 may be provided on the lower side of the toggle plates 38, 40 such that the abutments are arranged to come into contact with each other when retraction of the release mechanism reaches a predetermined extent.

With reference to Figure 9, an a lternative embodiment of the jaw crusher 2 is illustrated. Again like parts are denoted with like numerals. For the sake of brevity, only features which differ from the embodiments discussed above will be described.

In this embodiment, the first rotatable portion 16a of the coupling mechanism 16 comprises a pair of cams 56 which are fixed for rotation with the axis of rotation A. In the illustrated embodiment, the cams 56 are circular having their centre point 58 co axial with the axis of rotation A.

The pitman links 36 of the linking arrangement 28 are coupled to the cams 56 at attachment location 60. The attachment location 60 is radially offset from the axis of rotation A by the first offset amount P. In this way, rotation of the cams 56 about the axis of rotation A will result in the upper end of the pitman link 36 prescribing a circle about the axis of rotation A.

The point of attachment 60 of the pitma n link 36 to the cam 56 can be thought of as equating to the centre point of an eccentric component, for example the eccentric disc 24 as described in relation to the embodiment illustrated in Figures 1-5. The arrangement of Figure 9 results in similar rotation of the upper end of the pitman links 36 around the axis of rotation as is obtained by the eccentric disc 24 arrangement, and consequently similar reciprocal motion at the lower end of the pitman links 36.

Accordingly this results in similar motion of the moveable jaw 8.

It will be appreciated that a cam having a non-circular shape or a crank mechanism may be used to couple the pitman link 36 to the shaft 12. It will also be appreciated that, in exemplary embodiments, the pitman link may be attached directly to a circular end face of the shaft 12, rather than a separate cam. In such embodiments, the pitman link 36 is attached directly to the circular end face of the shaft at the attachment location 60 such that rotation of the shaft causes the end of the pitman link 36 proximal the shaft 12 to rotate (i.e. prescribe a circle) about the axis of rotation A.

Although the invention has been described in relation to one or more embodiments, it will be appreciated that various changes or modifications can be made without departing from the scope of the invention as described in the appended claims. For example, it will be a ppreciated that any suitable coupling mechanism may be used to couple the pitman links 36 (i.e. the linking arrangement 28) to the shaft 12.