FIELD OF THE INVENTION

[0001] The present invention relates to an adjustment mechanism for a crusher, in particular a gyratory crusher as disclosed in PCT/AU2014/000746 with a mechanism to adjust the clearance between the mandrel and shell.

BACKGROUND TO THE INVENTION

[0002] The present applicant is also the applicant for PCT/AU2014/000746 in which an adjustable super fine crusher for the comminution of mineral ores is disclosed. In a preferred embodiment the crusher comprises a gyrating cylindrical mandrel which crushes material against a shell comprising two end to end frustoconical sections. The exact geometry of the crushing chamber is determined by the angle of the cones as well as the angle of the shell relative to the mandrel. Preferably the crushing chamber tapers towards the intersection of the two frustoconical sections. It was desirous to be able to adjust the crushing gap and an embodiment of the crusher was developed to allow this in which the outer shell was vertically displaced with respect to the mandrel. This required the shell to be changed to a single frustoconical section and the mandrel to be changed to a frustoconical section adjoining a cylindrical section. This

arrangement allowed the crushing gap to be altered at the feed end of the chamber to handle coarser feed, but as it altered the crushing gap uniformly along the length of the mandrel it also altered the crushing gap at the product end of the chamber resulting in coarser product. This was not desired.

[0003] The object of this invention is to provide a crusher with an adjustment mechanism that adjusts the crushing gap non-uniformly along the length of the crushing chamber to alleviate the above problem, or at least provide the public with a useful alternative.

SUMMARY OF THE INVENTION

[0004] In a first aspect the invention provides crusher with an adjustment mechanism, comprising a mandrel and a shell defining a crushing chamber, wherein the shell is pivotably mounted with respect to the mandrel to adjust the geometry of the crushing chamber. [0005] Preferably the shell is pivoted with respect to the mandrel by a hydraulic actuator and the crusher is operated at a constant pressure for a specific crushing chamber size thereby automatically compensating for wear in the mandrel or shell.

[0006] The mandrel is preferably cylindrical and the shell comprises two end to end frustoconical sections, or the mandrel comprises a cylindrical section and a

frustoconical section, and the shell comprises a frustoconical section.

[0007] It should be noted that any one of the aspects mentioned above may include any of the features of any of the other aspects mentioned above and may include any of the features of any of the embodiments described below as appropriate.

BRIEF DESCRIPTION OF THE DRAWINGS

[0008] Preferred features, embodiments and variations of the invention may be discerned from the following Detailed Description which provides sufficient information for those skilled in the art to perform the invention. The Detailed Description is not to be regarded as limiting the scope of the preceding Summary of the Invention in any way. The Detailed Description will make reference to a number of drawings as follows.

[0009] Figure 1 shows a prior art crusher.

[0010] Figure 2 shows a front perspective view of a crusher of the present invention incorporating an adjustment mechanism.

[0011] Figure 3 shows a rear perspective view of a crusher.

[0012] Figure 4 shows a partial side view of a crusher.

[0013] Figure 5 shows a cutaway partial side view of a crusher.

DRAWING COMPONENTS

[0014] The drawings include the following integers.

10 crusher

20 stand

30 body

32 shell

34 shell drive motor 36 shell motor pulley

38 shell pulley

40 mandrel

42 mandrel crushing element

44 mandrel drive motor

46 mandrel motor pulley

48 mandrel pulley

50 pivot

52 pivot point

60 hydraulic actuator

70 feed entry

72 crushing chamber maximum

74 crushing chamber minimum

Prior Art Crusher

100 prior art crusher

101 crusher body

102 shell

103 mandrel

104 hydraulic adjuster

DETAILED DESCRIPTION OF THE INVENTION

[0015] The following detailed description of the invention refers to the

accompanying drawings. Wherever possible, the same reference numbers will be used throughout the drawings and the following description to refer to the same and like parts. Dimensions of certain parts shown in the drawings may have been modified and/or exaggerated for the purposes of clarity or illustration.

[0016] The present invention provides a crusher with an adjustment mechanism, the crusher incorporating a cylindrical mandrel and a shell comprising two end to end frustoconical sections as disclosed in PCT/AU2014/000746. The crushing gap is varied proportionately along the length of the mandrel for more desirable crushing control in contrast with previous mechanism which provided a uniform adjustment and

necessitated a change in mandrel and shell geometry.

[0017] Figure 1 shows a partial cutaway view of a prior art crusher with and adjustment mechanism s disclosed in PCT/AU2014/000746. The prior art crusher 100 comprises a crusher body 101 with a bearing mounted frustoconical shell 101. A mandrel 103 comprising a cylindrical section joined to frustoconical section gyrates within the shell to crush material in the gap between the shell and the mandrel. The specific geometry selected provides a uniform gap between the shell and the crusher which can only be adjusted in a uniform manner by raising or lowering the shell with respect to the mandrel with the aid of hydraulic actuators 104.

[0018] The present invention is described with the aid of Figures 2 to 5, with

Figures 2 to 4 showing the general arrangement of the crusher and Figure 5 providing a detailed cutaway view comparable to the view of the prior art mechanism shown in Figure 1.

[0019] Figure 2 shows a front perspective view of a crusher 10 which comprises a stand 20 to which a body 30 is mounted via pivot 50. Attached to the stand is motor 44 for driving the mandrel 40 (not visible) and attached to the body is shell drive motor 34 which drives the shell 32 (not visible) via shell motor pulley 36 and shell pulley 38 using multiple drive belts (not shown). Hydraulic actuator 60 serves to rotate the body 30 about pivot point 50.

[0020] Figure 3 provide a rear perspective view of the crusher 10 in which a second hydraulic actuator 60 can be seen.

[0021] Figures 4 and 5 allow the adjustment mechanism to be appreciated with Figure 4 providing an external partial side view showing the relationship between the stand 20, body 30, pivot 50 and actuator 60, whilst Figure 5 provides the same view cutaway to see the inner mechanism, in particular the relationship between the mandrel and the shell. The pivot cannot be seen in Figure 5 but passes through pivot point 52 (marked with an "X") which aligns with the centre of the mandrel 40 and the centre point between where the two frustoconical sections of the shell 32 meet.

[0022] Similar to the prior art crusher, the crusher 10 comprises shell 32 which is mounted by bearings in body 30 at the centre of which gyrates mandrel 40. Feed is introduced into the crusher via feed entry 70 and into the crushing chamber at maximum 72 and moved around to minimum 74 as the shell rotates. As shown the chamber minimum 74 is at its smallest. To increase the chamber minimum 74 hydraulic actuator 60 is retracted causing the body 30 and shell 32 to rotate about the pivot point 52. The chamber will open up as the shell moves away from the mandrel, with the extent of the opening proportional to the distance from the pivot point. Further control in the relative opening may be achieved by relieving the mandrel about its mid-point.

[0023] From an external point of view a visual marker with an appropriate scale or an electronic encoder can easily measure the size of the chamber minimum and hence product size.

[0024] To set a particular chamber size the hydraulic actuator must overcome the resistance of the material bed that forms in the chamber between the shell and the mandrel. As the shell and mandrel wear a particular hydraulic pressure will maintain a constant bed depth regardless, acting as a wear compensating mechanism. The hydraulic actuator will also act as a safety mechanism. If the chamber becomes jammed the hydraulic actuator will attempt to apply a constant force, which will tend to open up the chamber in a jam situation and prevent damage to the crusher.

[0025] The pivoting mechanism to adjust the rushing chamber geometry may be used with varying shell and mandrel geometries and is even suited for use with shells and mandrels as used in the prior art crusher of Figure 1.

[0026] The reader will now appreciate the present invention which provides an adjustment mechanism for a crusher which allows the crushing chamber size to be varied in proportion to the position in the chamber.

[0027] Further advantages and improvements may very well be made to the present invention without deviating from its scope. Although the invention has been shown and described in what is conceived to be the most practical and preferred embodiment, it is recognized that departures may be made therefrom within the scope of the invention, which is not to be limited to the details disclosed herein but is to be accorded the full scope of the claims so as to embrace any and all equivalent devices and apparatus. Any discussion of the prior art throughout the specification should in no way be considered as an admission that such prior art is widely known or forms part of the common general knowledge in this field.

[0028] In the present specification and claims (if any), the word "comprising" and its derivatives including "comprises" and "comprise" include each of the stated integers but does not exclude the inclusion of one or more further integers.