CROSS-REFERENCE TO RELATED APPLICATION

This application claims priority to South African provisional patent application number 2013/05701 filed on 29 July 2013, entitled "A Crusher", which is incorporated by reference herein.

FIELD OF THE INVENTION

This invention relates to a crusher for fracturing or comminuting materials, and, more particularly, to crusher wear parts and fitment thereof.

BACKGROUND TO THE INVENTION

Crushers are commonly used to fracture or comminute materials. In industry, crushers are typically used as part of mining and construction operations.

Many varieties of crushers exist. Due to the highly abrasive and destructive nature of crushing, crushers may be provided with replaceable wear parts. These wear parts may be in the form of plates, hammers, cones and the like, depending on the type of crusher.

Robust, secure attachment of crusher wear parts to the crusher is required. However, a notable disadvantage of some crushers is that the crusher wear parts may be difficult to remove and replace due to their weight and the manner in which they are secured to the crusher. This results downtime and reduced throughput in crushing operations. Furthermore, certain crusher wear parts are manufactured in a casting process which may have a relatively high cost associated therewith. The present invention aims to alleviate these and other problems, at least to some extent.

In this specification, the term "wear parts" shall have its widest meaning and shall include any parts in direct contact with material being crushed during a crushing operation, including hammers or hammer-like structures, backing plates and jaw structures. The term "wear surface" shall also have its widest meaning and shall include any surface of a wear part which is in direct contact with material being crushed during a crushing operation.

SUMMARY OF THE INVENTION

In accordance with the invention there is provided a crusher having replaceable wear parts, the crusher being characterised in that the wear parts are provided by rails each having at least a web extending from a head and wherein the web of each rail is secured to the crusher such that the head provides a wear surface.

Further features provide for the rails to be removably secured to the crusher in complementary slots provided on the crusher; for one or more of the rails to have a foot extending from the web opposite the head; for the web and foot of each rail to be removably secured to the crusher; and for the web and foot of each rail to be removably secured to the crusher in the complementary slots provided on the crusher.

Yet further features provide for the slots to provide a degree of lateral movement to the rails within the slots; alternatively, for each rail to provide a location fit within a slot.

Still further features provide for the rail to be a railroad track rail; for the rail to be one of a flat-bottom rail, a bullhead rail, a grooved rail, a Vignoles rail, a footless rail and a flanged T rail; and for the rail to have a cross-section approximating that of an I-beam.

The crusher may be configured for use as an impact crusher or as a jaw crusher.

According to a first aspect, the crusher is configured for use as an impact crusher and includes a rotor to which at least two rails are secured.

Further features provide for the rails to be substantially evenly spaced about the circumference of the rotor; for the rotor to have a substantially cylindrical shape and a generally circular axial cross-section; alternatively, for the rotor to have a generally rectangular axial cross-section.

According to a second aspect, the crusher is configured for use as a jaw crusher and includes a crusher jaw to which rails are secured.

Further features provide for the rails to extend substantially parallel to each other across a length of the crusher jaw; for the crusher jaw to include rail holders to which the rails are secured; for each rail holder to have a stem extending generally normally from an operative surface of the jaw and terminating in a flange at a free end of the rail holder; and for the complementary slots to be defined by stems and flanges of adjacent rail holders.

A yet further feature provides for the heads of adjacent rails to substantially abut along their length.

The invention extends to a rotor for use in an impact crusher substantially as described above, and to a crusher jaw for use in a jaw crusher substantially as described above. In order for the invention to be more fully understood, implementations thereof will now be described with reference to the accompanying drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

The invention will now be described, primarily by way of example, with reference to the accompanying representations in which:

Figure 1 is a three-dimensional view of a first embodiment of a rotor of a crusher;

Figure 2 is an end view of the rotor of Figure 1 , wherein crusher wear parts are secured to the rotor;

Figure 3 is an end view of a second embodiment of a rotor of a crusher, wherein crusher wear parts are secured to the rotor;

Figure 4 is a three-dimensional view of a third embodiment of a rotor of a crusher;

Figure 5 is an end view of the rotor of Figure 4;

Figure 6 is a three-dimensional view of the rotor of Figure 4, wherein crusher wear parts are secured to the rotor;

Figure 7 is an end view of the rotor shown in Figure 6;

Figure 8 is a three-dimensional view of a first embodiment of a crusher jaw of a crusher; Figure 9 is a cross-sectional view of the crusher jaw of Figure 8, wherein crusher wear parts are secured to the crusher jaw;

Figure 10 is a three-dimensional view of a second embodiment of a crusher jaw of a crusher, wherein crusher wear parts are secured to the crusher jaw; and,

Figure 1 1 is an end view of the crusher jaw of Figure 10.

DETAILED DESCRIPTION WITH REFERENCE TO THE DRAWINGS

Embodiments of a rotor and a crusher jaw of a crusher are shown in Figures 1 to 1 1 . Crusher wear parts are removably secured to these. The wear parts are provided by rails each having at least a web extending normally from a head. The web of each rail is secured to the crusher such that the head provides a wear surface for fracturing or comminuting materials in use.

In a first embodiment which is shown in Figures 1 and 2, a rotor (102) configured for use in an impact crusher is provided. The rotor (102) is cylindrically shaped and generally circular in cross-section along its longitudinal axis (A). A circular bore (108) is provided through the rotor (102) along the central, longitudinal axis (A) thereof. The bore (108) is configured to receive a shaft (not shown) to which the rotor (102) is secured to permit it to be rotated about its longitudinal axis (A). The bore (108) may be keyed or splined in conventional fashion to assist in preventing relative rotation between the rotor (102) and shaft.

Two longitudinally extending slots (104) are provided in the rotor (102) and are evenly spaced about its circumference. The slots (104) are T-shaped in cross-section, each providing a stem (107) extending in a radial direction inwardly from the outer surface (106) and terminating in a normally extending cross-piece (109).

Two elongate, flat-bottom rails (1 14) are shown in Figure 2, each having a web (1 10) which extends normally between a foot (1 1 2) and a head (1 16). The slots (104) are shaped to provide a location fit over the foot (1 12) and part of the web (1 10) of the rails (1 14). The rails (1 14) can thus be removably secured to the rotor (102) by sliding each into a slot (104) from one end and securing it in position. The head (1 16) of each rail (1 14) projects from the outer surface (106) of the rotor (102) when secured to the rotor (102), as shown in Figure 2.

Any suitable means may be provided to secure the rail (1 14) in position once inserted into a slot. For example, the rail (1 14) can be held in position by a securing plate which is bolted to the rotor (102) at one or both ends thereof. Alternatively, one or more set bolts may be employed for this purpose.

In use, the rotor (102) forms part of an impact crusher for fragmenting or comminuting materials. Typically, the materials are contained in a cage with openings of a desired size at the bottom, end, or side thereof to allow crushed material to escape. The rotor (102), or a plurality of rotors, depending on the application, is rotated about the longitudinal axis (A) while the heads (1 16) of the rails (1 14) act as hammers which impact the materials in order to fragment it or otherwise reduce the size thereof.

The rails may be railroad track rails. The railroad track rails may be new or used. Railroad rails, due to the high stresses and loads they are subjected to in conventional use, are typically manufactured from steel alloys using a hot rolling process. The steel alloys used to manufacture railroad rails may be of a high quality, for example, high quality pearlite rail steel alloys. Such rails provide adequate tensile strength, density, hardness, wear resistance and fatigue properties in order to satisfactorily fracture materials over a desired period of time and have been found to serve as excellent wear parts.

The steel alloys used to manufacture railroad rails may be preferable over steel alloys used to produce conventional crusher wear parts in a casting process. Being widely available both in used and new condition makes use of the rails in this application cost-effective. In particular, used railroad tracks may in some cases be obtained at the cost of so-called "scrap steel", which significantly reduces the cost of obtaining and replacing crusher wear parts. Furthermore, wear parts manufactured in a casting process may initially have inaccurate dimensions, requiring machining to be performed to obtain desired dimensions.

The rails can be relatively easily and quickly removed and replaced, for example, after they become worn or damaged, thus reducing downtime and increasing throughput.

Furthermore, the use of rails in the manner described obviates the difficulty traditionally associated with replacing worn or damaged wear parts during or after crushing operations, particularly as the rails do not have to be welded to the crusher or secured using fasteners that are subject to wear themselves. The rails can be replaced without requiring extensive resources, highly skilled labour or sophisticated tooling equipment. This results in less time being lost due to replacement operations.

The rails shown in the accompanying figures are flat-bottom railroad track rails. However, it should be appreciated that any suitable rail or rail-shaped element may be employed as a crusher wear part without departing from the scope of the invention. For example, the rail may be a bullhead rail, grooved rail, Vignoles rail, flanged T rail, or any suitable element with a cross-section approximating that of an I-beam. A footless rail or other suitable element with a T-shaped cross-section may also be used as a crusher wear part, as will be apparent from the further description below.

Many alternative shapes and configurations are envisaged, particularly in terms of the crusher wear parts and slots for receiving the crusher wear parts. One such alternative configuration is shown in Figure 3, which is a second embodiment of a rotor (202) configured for use in an impact crusher. The rotor (202) has a generally rectangular cross-section along its longitudinal axis and two complementary slots (204) for receiving crusher wear parts extend longitudinally therealong.

The rotor (202) of Figure 3 is similar to the rotor (202) of Figures 1 and 2. However, in this embodiment, each slot (204) in cross-section provides an inwardly tapering opening (218) which extends radially inwardly from the outer surface (206) and enters centrally into a cavity (219) within the rotor (202) which is substantially triangular in cross-section. The cross-section of the cavity (219) is defined by a first side (221 ) through which the opening (218) enters, a second side (223) inclined at an acute angle relative to the first side (221 ), and a third side (225) extending arcuately between the first (221 ) and second (223) sides. The first side (221 ) and second side (223) are slightly longer than the width of a foot (210) of a rail (212), while the third side (225) is approximately half the width thereof.

The configuration of the slots (204) in this embodiment provides a degree of lateral movement to the rails when secured to the rotor (202) by sliding each into a slot (204) substantially as described above with reference to the embodiment in Figure 2. One edge (227) of the foot (210) locates in the junction between the first side (221 ) and second side (223) of the slot (204) and provides a pivot about which the opposite edge (228) can move. The foot (210) of a rail (212) is thus movably received in the slot (204) so as to enable the web (214) and head (216) of the rail (212) to protrude at variable angles from the opening (218) at the outer surface (206) of the rotor (202) by pivoting about the edge (227) of the foot (210). The variability in inclination of the rail (212) when received in the slot (210) is indicated by the broken lines (220) in Figure 3.

In use, the rotor (202) forms part of an impact crusher for fragmenting or comminuting materials, and functions in a similar manner to the rotor (102) described with reference to Figures 1 and 2. The rotor (202) is rotated about its central, longitudinal axis in the direction indicated by the directional arrow (230) in Figure 3.

Whereas the slots of the rotor (102) of Figures 1 and 2 receive rails by way of a location fit, the slots (204) shown in Figure 3 permit the rails (212) to be movably secured to the rotor (202) such that a degree of lateral movement is provided to the rails (212). The foot (210) of the rail (212) is able to move between the first side (221 ) and second side (223) and along the third side (225) of the slot (204) in use. This enables the rail (212) to move on impact with materials and thereby improves the ability of the rail (212) and the rotor (202) to absorb and withstand forces or pressure to which they are subjected during operation. This pivoting ability may also reduce the risk of the rotor (202) becoming jammed, especially in cases where large rocks contained in a crusher cage must be fragmented.

The rotor (202) may be configured such that, during rotation of the rotor (202) at a predefined rate, centrifugal forces acting on the rail (212) hold the rail (212) in an operative position in which the foot (210) of the rail (212) abuts the first side (221 ) of the slot (204), as shown in Figure 3. In such a case, once the rail (212) is subjected to a force or resistance greater than and acting against the centrifugal forces acting thereon, the rail (212) pivots such that the edge (228) of the foot (210) moves towards the second side (223) of the slot (204). A further embodiment of a rotor (250) for an impact crusher is shown in Figures 4 to 7. The rotor (250) includes a shaft (252) provided with a number of flywheels (254) evenly spaced along a length of the shaft (252). The flywheels (254) are secured so as to operatively rotate with the shaft (252) about its longitudinal axis (B) in the direction indicated by the directional arrow (256) in Figures 5 and 7.

Each flywheel (254) is provided with a number of rail slots (258) for receiving a foot (259) and web (260) of a rail (261 ), each slot having a T-shaped axial cross-section complementary to that of the rail (261 ). The rail slots (258) of the flywheels (254) are evenly spaced about the circumference of each flywheel (254), and the rail slots (258) of respective flywheels (254) are longitudinally aligned such that a rail (261 ) can be slid through each of the slots (258) and secured to the rotor (250). In this embodiment, three rails (261 ) can be secured to the rotor (250), as shown in Figures 6 and 7.

Each flywheel (254) is further provided with a support bar slot (262) adjacent each rail slot (258). The support bar slots (262) are generally rectangular in axial cross-section and shaped to receive a complementary support bar (264) which acts to reinforce the rotor (250) by abutting an adjacent rail (261 ). Similarly to the rail slots (258), support bar slots (262) of respective flywheels (254) are longitudinally aligned such that a support bar (264) can be slid into position and secured to the rotor (250), as shown in Figures 6 and 7.

The perimeter of each flywheel (254) extends outwardly in a spirally radial direction from one side of each rail slot (258) to the support bar slot (262) of the adjacent rail slot (258), such that radial distance from the shaft (252) to the support bar slot (262) is greater than the radial distance from the shaft (252) to the rail slot (258). This configuration permits the support bar (264) to abut the head (265) of an adjacent rail (261 ) whilst the opposite side of the head is unobstructed, as most clearly illustrated in Figure 7. Furthermore, the top (267) of each support bar (264) is inclined to be substantially complementary to the perimeter of the flywheels (254).

The support bars (264) are secured to the flywheels (254) by bolts (266), and the rails (261 ) are held in position by side plates (268) which are bolted to flywheels (254) at either end of the rotor (250). A disc-shaped cover plate (270) is further provided at either end of the rotor (250), as shown in Figure 6. Each cover plate (270) is secured over the shaft (252) at either end of the rotor (250) and defines openings (272) shaped to receive the side plates (268) and permit individual side plates (268) to be removed without having to remove the cover plate (270).

In use, the rotor (250) rotates about its longitudinal axis (B) and the heads (265) of the rails (261 ), typically the unobstructed sides of the heads, act as wear parts for fragmenting material, substantially as described with reference to Figures 1 and 2. In this embodiment, the support bars (264) which abut the head (265) act to support the rails (261 ) by absorbing some of the impact and/or pressure the rails (261 ) are subjected to in use.

The head (265) of the rail (261 ) is positioned so as to substantially prevent the support bar (264) from coming into direct contact with materials to be crushed in use. The support bar (264) is thus subjected to less wear than the rail (261 ) and frequent replacement thereof may not be required.

The crusher has been described as an impact crusher with reference to Figures 1 to 7. In a further embodiment which is shown in Figures 8 and 9, a crusher jaw (300) is provided which is configured for use in a jaw crusher.

The crusher jaw (300) has an elongate mounting plate (302) which includes a substantially planar base plate (304) and a number of outwardly protruding rail holders (306) secured to and extending in parallel across one side (309) of the base plate (304), the side (309) defining an operative surface. Each rail holder (306) has a stem (307) extending normally from the side (309) of the base plate (304) with a flange (31 1 ) at its opposite end, as is more clearly shown in Figure 9. Adjacent rail holders (306) define between each other generally T-shaped slots (308) which are complementary to a foot and web of a rail to removably secure the rail to the crusher jaw (300).

A web (312) and a foot (314) of an elongate flat-bottom rail (316) can be removably secured to the crusher jaw (300) by sliding the rail into a T-shaped slot (308). The web (312) and foot (314) are secured to the jaw (300) such that a head (318) of the rail (316) protrudes from the rail holders (306) above the mounting plate (302).

Furthermore, a narrow, rectangular slot (310) extends centrally across each flange (31 1 ) at the free end thereof, with a groove (317) provided on each side of the slot (310). A web (320) of a footless rail (322) can be secured to the crusher jaw (300) by inserting it into the slot (310) in the flange (31 1 ) of a rail holder (306). The web (320) is secured to the jaw (300) such that the head (324) of the footless rail (322) protrudes from the mounting plate (302) in a similar manner to the heads (318) of the flat-bottom rails (316).

The rails (316, 322) are secured so as to extend parallel to each other in a longitudinal direction across the crusher jaw (300), as is more clearly shown in Figure 8.

Any suitable means may be provided to securely hold the flat-bottom rails (316) and footless rails (322) in position once inserted. For example, the flat- bottom rails (316) can be held in position by way of a securing plate (not shown) which is bolted to the mounting plate (302) at one or both ends thereof and the footless rails (322) can be secured in the slots (310) by pins (not shown) extending therethrough between the grooves (317). In a jaw crusher, one jaw is typically kept stationary while a movable jaw or swing jaw moves back and forth relative to it in order to crush materials contained in a crushing chamber. The crusher jaw (300) of Figures 8 and 9 is capable of serving as a stationary jaw or a movable jaw in a jaw crusher. Both jaws will preferably be of the type described in Figures 8 and 9. Upon impact, the heads (318, 324) of the rails (316, 322) provide a wear surface which enables fragmentation of materials.

Similarly to the embodiments described above, the crusher jaw (300) of Figures 8 and 9 allows rails to be relatively easily removed and replaced, for example, after they become worn or damaged. Use of railroad track rails also provide adequate tensile strength, hardness, wear resistance and fatigue properties in order to satisfactorily fracture materials over a desired period of time, and these rails can be obtained relatively inexpensively.

It is envisaged that numerous alternative crusher jaw configurations can be implemented. For example, the heads of adjacent rails may substantially abut in order to prevent material from becoming trapped between the rails. An embodiment of a crusher jaw (350) in which heads of adjacent rails abut is illustrated in Figures 10 and 1 1 .

The crusher jaw (350) includes a base plate (352) and a number of outwardly protruding rail holders (354) each secured to the base plate (352). The rail holders (354) extend in parallel across an operative surface (358) of the crusher jaw.

Each rail holder (354) includes a number of spaced apart holding elements (359) connected by a connecting plate (361 ). Each holding element (359) has a stem (360) from which extends a threaded shaft which extends through an aperture in the base plate (352) and is secured thereto by a nut (356). The stem (360) terminates in a flange (362) opposite the threaded shaft and which is shaped to be complementary to the junction of the web (368) and foot (366) of a rail (370). Adjacent rail holders (354) thus define between them slots (364) which are complementary to a foot (366) and web (368) of a rail (370) and through which a rail can be removably secured to the crusher jaw (350).

In this embodiment the connecting plate (361 ) is welded to the top of each flange (362) and assists in quickly inserting and removing the threaded shafts of each holding element from the respective apertures in the base plate (352).

A rail (370) can be secured to the crusher jaw (300) by loosening or removing the nuts (356) of the appropriate rail holders (354), positioning the rail (370) between the rail holders (354) and fastening the nuts (356) so as to firmly hold the rail (370) in place. Tightening of the nuts (356) causes the foot (366) of the rail (370) to be firmly captured between the flanges (362) of each holding element (359) and the operative surface (358) and to so be held in place.

In this embodiment, the rails (370) are arranged such that their heads (372) substantially abut along the length of the rails (370). This prevents material ingress between the rails and may also provide lateral support to the rails. To permit the rails (370) to abut, the foot (366) of each rail (370) may be appropriately trimmed. The crusher jaw (350) of Figures 10 and 1 1 may be operated in a similar manner to the crusher jaw (300) of Figures 8 and 9.

In some conventional jaw crusher applications, large wear plates may be used as wear parts. For example, one or two large wear plates may be secured to a mounting plate to form a crusher jaw. These wear plates are typically heavy and difficult to remove or replace without lifting equipment. In the embodiments of crusher jaws described herein, individual rails can be removed separately, allowing for replacement of worn rails only. The worn rails may be replaced using manual labour instead of lifting equipment. A crusher is thus provided which is fitted with rails as crusher wear parts, which may be new or used railroad track rails or other suitable rails as described above. The rails preferably serve as replacement hammers, jaws and/or crushing plates for impact crushers and jaw crushers.

The above description is by way of example only and it should be appreciated that numerous changes and modifications may be made to the embodiment described without departing from the scope of the invention, particularly regarding the shape or configuration of the rails and the method by which they are secured in place.

While it is preferred that the rails be removably secured, they could also be welded in place or secured by any other suitable method. In embodiments of a rotor for an impact crusher, any number of longitudinally extending slots may be provided on the rotor for securing a desired number of rails to the rotor. Additionally, while the embodiments described herein relate to impact crushers and jaw crushers, the invention is not restricted to crushers of these types.