Patent Publication Number: US-2020276592-A1

Title: Pressure plate apparatus

Description:
TECHNICAL FIELD 
     Embodiments disclosed herein relate generally to cone crushers and more specifically to a system for preventing the tendency of a cone crusher head to elevated and/or to rotate. 
     BACKGROUND 
     Cone crushers are typically used to crush large rocks into smaller rocks at quarries. They include a conical crushing head that gyrates with a central shaft, the gyration of which is caused by a rotating eccentric surrounding the shaft. A hardened mantle covers the crushing head to crush rocks between it and a hardened liner of the crusher bowl in a crushing zone. The eccentric is driven by a diesel engine or electric motor power drive. 
     A cone head ball surface is typically mounted to the central shaft. This ball surface carries downward thrust loads, which it passes on to a stationary socket and thrust bearings disposed below the ball surface and socket interface. The thrust forces push the ball surface down on the stationary socket, creating friction that normally holds the shaft from rotating with the rotation of the eccentric. The downward thrust forces are anything but constant as the mantle gyrates and rocks enter and exit the crushing chamber. Without constant and substantial friction between the ball, which is mounted to the central shaft, and the stationary socket, the shaft and the mantle mounted to it may tend to rotate, which may create problems with the operation of the crusher. 
     Another drawback with some existing cone crushers is that, under particularly cold conditions, some cone crushers will exhibit what is called “cone head lift.” This phenomenon sometimes occurs during warm up of the crusher in cold weather, when the lubricating oil is especially viscous. Under these conditions, high internal fluid pressure may exceed the weight of the shaft and head, causing the head to lift. This can result in oil leakage and oil contamination, as well as damage to the oil seals. This cone head lift can be addressed by keeping a relatively constant downward pressure on the shaft, preventing the lifting even when forces generated by the thickened oil exceed the weight of the shaft and head. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       Embodiments will be readily understood by the following detailed description in conjunction with the accompanying drawings and the appended claims. Embodiments are illustrated by way of example and not by way of limitation in the figures of the accompanying drawings. 
         FIG. 1  is a side elevation sectional view of a cone crusher incorporating the disclosed embodiment of the pressure plate apparatus; 
         FIG. 2  is an enlarged, fragmentary side elevation view of the pressure plate apparatus embodiment shown in  FIG. 1 ; 
         FIG. 3  is a perspective view of the top side of the embodiment of the pressure plate of  FIGS. 1 and 2 ; 
         FIG. 4  is a perspective view of the bottom side of the embodiment of the pressure plate of  FIGS. 1 and 2 ; 
         FIG. 5  is a top plan view of the pressure plate of  FIGS. 3 and 4 ; 
         FIG. 6  is a side elevation view of the pressure plate of the prior figures; 
         FIG. 7  is a bottom view of the pressure plate of the prior figures; 
         FIG. 8  is a side elevation sectional view taken along line  8 - 8  of  FIG. 5 ; 
         FIG. 9  is a perspective view of the bottom of a thrust disc washer of the embodiment of  FIGS. 1 and 2 ; 
         FIG. 10  is a bottom view of the thrust disc washer of  FIG. 9 ; 
         FIG. 11  is a side elevation sectional view of the thrust disc washer taken along line  11 - 11  of  FIG. 10 ; 
         FIG. 12  is a perspective view from the top of an end cap of the embodiment of  FIGS. 1 and 2 ; 
         FIG. 13  is a top plan view of the embodiment of the end cap of  FIG. 12 ; 
         FIG. 14  is a side elevation view of the end cap of  FIGS. 13 and 14 ; 
         FIG. 15  is a front elevation view of the end cap of  FIGS. 13 and 14 , taken from a vantage point offset by  90  degrees from that of  FIG. 14 ; 
         FIG. 16  is a bottom view of the end cap of  FIGS. 13 and 14 ; 
         FIG. 17  is a perspective view of the housing of the embodiment of  FIGS. 1 and 2 , taken from a bottom angle; 
         FIG. 18  is a perspective view of the housing of the embodiment of  FIGS. 1 and 2 , taken from an upper angle; 
         FIG. 19  is a bottom view of the housing of the embodiment of  FIGS. 1 and 2 ; 
         FIG. 20  is a side elevation view of the housing of the embodiment of  FIGS. 1 and 2 ; and 
         FIG. 21  is a sectional view of a portion of the pressure plate apparatus taken from an upper perspective. 
     
    
    
     DETAILED DESCRIPTION OF DISCLOSED EMBODIMENTS 
     In the following detailed description, reference is made to the accompanying drawings which form a part hereof, and in which are shown by way of illustration embodiments that may be practiced. It is to be understood that other embodiments may be utilized and structural or logical changes may be made without departing from the scope. Therefore, the following detailed description is not to be taken in a limiting sense. 
     Various operations may be described as multiple discrete operations in turn, in a manner that may be helpful in understanding embodiments; however, the order of description should not be construed to imply that these operations are order-dependent. 
     The description may use perspective-based descriptions such as up/down, back/front, and top/bottom. Such descriptions are merely used to facilitate the discussion and are not intended to restrict the application of disclosed embodiments. 
     The terms “coupled” and “connected,” along with their derivatives, may be used. It should be understood that these terms are not intended as synonyms for each other. Rather, in particular embodiments, “connected” may be used to indicate that two or more elements are in direct physical or electrical contact with each other. “Coupled” may mean that two or more elements are in direct physical or electrical contact. 
     However, “coupled” may also mean that two or more elements are not in direct contact with each other, but yet still cooperate or interact with each other. 
     For the purposes of the description, a phrase in the form “A/B” or in the form “A and/or B” means (A), (B), or (A and B). For the purposes of the description, a phrase in the form “at least one of A, B, and C” means (A), (B), (C), (A and B), (A and C), (B and C), or (A, B and C). For the purposes of the description, a phrase in the form “(A)B” means (B) or (AB) that is, A is an optional element. 
     The description may use the terms “embodiment” or “embodiments,” which may each refer to one or more of the same or different embodiments. Furthermore, the terms “comprising,” “including,” “having,” and the like, as used with respect to embodiments, are synonymous, and are generally intended as “open” terms (e.g., the term “including” should be interpreted as “including but not limited to,” the term “having” should be interpreted as “having at least,” the term “includes” should be interpreted as “includes but is not limited to,” etc.). 
     With respect to the use of any plural and/or singular terms herein, those having skill in the art can translate from the plural to the singular and/or from the singular to the plural as is appropriate to the context and/or application. The various singular/plural permutations may be expressly set forth herein for sake of clarity. 
     The disclosed embodiment provides a continuous downward force on the crusher shaft, thus ensuring that there will be adequate friction between the previously-described ball and socket. This ensures that the head of the crusher will not rotate with the eccentric. 
     Embodiments include a system for maintaining a downward force on a central shaft of a cone crusher having a stationary frame, including a disc fixedly mounted to the frame, the disc having a centrally-disposed aperture with a first diameter. A plate is mounted to an end cap, the plate having a second diameter that is greater than the first diameter. The plate is disposed distally of the disc and the end cap is disposed proximally of the disc. A housing is fixed to the central shaft and biased away from the end cap wherein a downward bias is imparted to the central shaft. 
     The housing may be slidably mounted to the end cap and/or the plate. The plate may be threadably mounted to the end cap. The bias may be generated by at least one spring disposed between the housing and the end cap. Gyration may be imparted to the central shaft by an eccentric, and the gyration of the central shaft may be passed to the plate, which gyrates with respect to the disc. 
     The plate may be indirectly mounted to the central shaft such that any gyration of the central shaft is passed on to the plate, which gyrates with respect to the disc and is in contact with an underside of the disc at least part of the time. 
     The disclosed embodiments also include a pressure plate apparatus for mounting to a central shaft that gyrates in a cone crusher, the pressure plate maintaining a downward force on the central shaft during crushing operations. The apparatus may include a housing fixed to an underside of the central shaft, the housing slidably receiving an end cap and a raised portion of a plate. At least one spring may be mounted between the end cap and the housing to bias the plate toward the central shaft. A disc may be fixed to a stationary frame of the crusher, the disc having an aperture with a first diameter and being disposed between the plate and the housing, the plate having a second diameter that is greater than the first diameter. The plate may gyrate with the central shaft on the disc for some of the crushing operations and, in other crushing operations, the at least one spring may push the plate away from the disc to maintain a downward force on the central shaft. 
     Other embodiments may include a process for maintaining downward pressure on the cone of a cone crusher having a stationary frame, a central shaft, a first and a second thrust bearing surface mounted to the central shaft that absorb at least some downward thrust during crushing operations, and a rotating eccentric that gyrates the central shaft with respect to the frame. The process includes the following steps, not necessarily in the order recited: positioning at least one spring adjacent a housing; mounting an end cap to the housing such that the at least one spring is disposed between the housing and the end cap; fixing the housing to the central shaft and in doing so, compressing the at least one spring; fixing a disc to a lower portion of the frame, the disc having a centrally-disposed aperture having a first diameter; selecting a plate having a second diameter that is greater than the first diameter; and mounting the plate to the end cap such that the disc is disposed between the plate and the end cap so that when crushing operations are initiated, the plate will gyrate with the central shaft and with respect to the disc. The process may also include the step of maintaining spring tension on the central shaft, thus maintaining pressure between the first and second thrust bearing surfaces. 
     Crusher  10  is largely conventional, except for the pressure plate apparatus, generally indicated at  12 , at the bottom of the crusher.  FIG. 1  shows that cone crushers include a cone head  13  and a cone head ball surface  14 , which is mounted to a central shaft  16 . Ball surface  14  is disposed immediately above and rests against a stationary socket  18 , which is mounted indirectly to the central shaft. A mantle  20  is mounted to the top of central shaft  16 , which gyrates due to the action of a surrounding, rotating eccentric  22 . The action of the gyrating mantle  20  against a stationary bowl liner  22  breaks down rocks that enter a crushing zone  24  extending between the mantle and the liner. All of the foregoing components are mounted within a stationary crusher frame  26 . 
     When rocks are fed into a crushing chamber  24 , a crushing force acts on mantle  14 , pushing the mantle downward and pressing central shaft  16  against a radial bearing  28 . But most of the downward force is transmitted from central shaft  16  to ball surface  14  and stationary socket  16  and to a pair of flat, ring-type thrust bearings  30 . As described above, this downward thrust of central shaft ball surface against stationary socket  16  creates friction between the ball surface and the socket, tending to prevent central shaft  18  and mantle  20  mounted to it from rotating. However, given the substantial and widely varying thrust forces generating during crushing operations, this force and therefore the amount of friction will vary greatly, providing for the possibility that cone head ball surface  14 , central shaft  16  and mantle  20  may from time to time, rotate. 
     To counter this possibility and to provide a relatively constant amount of pressure between cone head ball surface  14  and stationary socket  18 , pressure plate apparatus  12  is provided. This relatively constant pressure is effected by providing a constant downward force on central shaft  16  using a series of springs, the operation of which will be explained as this discussion continues. 
       FIG. 1  shows a typical position of a pressure plate  38  in pressure plate apparatus  12 . As shown best in  FIG. 2 , pressure plate  38  is bolted to an end cap  52  by a bolt  34 . A bolt head  32  is smaller than the bolt hole so that pressure plate  38  is securely held in place. Pressure plate  38 , which is shown in detail in  FIGS. 3-8 , may be generally circular in configuration. Thrust washer disc  40  is also generally circular in configuration as shown best in  FIGS. 9-11 , and includes a central aperture  43  that may be said to have a first diameter. Pressure plate  38  may be said to have a second diameter, which is larger than the first diameter of the thrust washer disc central aperture  43 . The outer periphery of thrust washer disc  40  includes a flange  42  that is bolted via bolt holes  44  to frame  26 . 
       FIG. 2  shows pressure plate  38  centrally disposed with respect to thrust washer disc  40  although that is because the disc is displaced rearwardly away from the viewer.  FIG. 1  shows pressure plate  38  at one side of thrust washer disc  40 . Given that eccentric  22  is always off to one side of center,  FIG. 1  more clearly illustrates the relative disposition of pressure plate  38  and thrust washer disc  40 . 
       FIGS. 3-8  illustrate that pressure plate  38  includes a bifurcated raised portion  45  comprised of two upwardly extending legs  46 , defined by a centrally disposed flat area  48 . Fitting slidably between legs  46  is a central extension  50  of an end cap  52 , which is shown best in  FIGS. 12-16 . The end cap also includes a raised annular shoulder  54  and a broad platform  56 . Platform  56  is generally circular but includes two opposed flattened edges  58 . 
     A housing  60  may also be included, which is designed to retain at least one spring. It is possible that a single spring may extend around the housing but the preferred, design includes a plurality of springs  62 . The housing is shown best in  FIGS. 14-17 . It is generally cylindrical but with many features designed to retain various components and fit within and between other components of pressure plate apparatus  12 . For example, housing  60  includes a cylindrical passage  64  designed to receive the raised portion  45  of pressure plate  38  as well as the central extension  50  of end cap  52 . The housing also includes generally cylindrical holes  66  designed to receive and retain springs  62 . In the depicted embodiment, fifteen such holes are included although there may be more or fewer holes. The holes  66  do not extend entirely through housing  60  so that springs  62  bottom out in the housing. Venting apertures  68  may be provided in each of the cylindrical holes  66 . 
     Also included in housing  60  are a plurality of bolt holes  70  evenly positioned around the periphery of the housing, provided with shoulders  72  to support the heads of bolts  74  that extend therethrough. As seen in  FIG. 21 , bolts  74  serve to mount housing  60  the central shaft  16 , which, again, gyrates from side to side with the rotation of eccentric  22  but should not rotate. As shown in  FIG. 18 , two flat segments  76  extend chord-like across two of the edges of the inner diameter of housing  60  to receive the flattened edges  58  of end cap  52  (see  FIGS. 12-16 ) to ensure that the housing does not rotate with respect to the adjacent components. 
     As seen best in  FIG. 2 , a shallow oil pan  78  is provided in the bottom of the crusher below the pressure plate apparatus  12 . Oil pan  78  will tend to collect lubricating oil as it drains from radial bearing  28  and an eccentric bearing  80  before draining through a drainage port (not shown) and returning to a lubricating oil reservoir (not shown). Oil flowing into pan  78  ensures that the sliding surfaces between the upper surface of pressure plate  38  and the lower surface of thrust washer disc  40  are fully lubricated and sufficiently cooled while shaft  16  gyrates from side to side and the pressure plate and thrust washer disc surfaces are sliding across each other. 
     The lubrication between the upper surface of pressure plate  38  and the lower surface of thrust washer disc  40  is further facilitated by the fact that the pressure plate may from time to time during crushing operations be moving slightly up and down with respect to the thrust washer disc, as shown by the arrows in  FIG. 2 .  FIG. 2  depicts pressure plate  38  in its upper-most position against thrust washer disc  40 . Upward and downward axial movement of pressure plate  38  is made possible by springs  62 , which provide a pulling force on central shaft  16 . This in turn ensures that there is pressure between the previously-discussed cone head ball surface  14  and stationary socket  18 , minimizing and normally preventing rotation of cone head  13  and central shaft  16 . This relatively constant pressure between ball surface  14  and socket  18  also minimizes and normally prevents any cone head lift, resulting from overly-viscous lubricating oil during start up in cold conditions. The cone head ball surface and the stationary socket may sometimes be referred to herein as a first and a second thrust-bearing surface. 
     Although certain embodiments have been illustrated and described herein, it will be appreciated by those of ordinary skill in the art that a wide variety of alternate and/or equivalent embodiments or implementations calculated to achieve the same purposes may be substituted for the embodiments shown and described without departing from the scope. Those with skill in the art will readily appreciate that embodiments may be implemented in a very wide variety of ways. This application is intended to cover any adaptations or variations of the embodiments discussed herein. Therefore, it is manifestly intended that embodiments be limited only by the claims and the equivalents thereof.