Patent Publication Number: US-5833153-A

Title: Rotor assembly for horizontal impact crusher

Description:
BACKGROUND OF THE INVENTION 
     The present invention generally relates to crushing machines for materials benefication, and more particularly to horizontal impact crushers having a rotor assembly with replaceable blow bars. 
     Horizontal impact crushing machines are well-known in the art and have been in use for many years. Such machines utilize the &#34;blow bars&#34; (sometimes called &#34;breakers&#34; or &#34;impact&#34; bars) which project from the periphery of the body of a rotor assembly rotating at high speeds to propel crushable material fed into the machine against hardened surfaces, called &#34;curtains,&#34; such that, the impact forces of the material striking the hardened surfaces cause the material to break up into smaller pieces. The machine&#39;s blow bars experience considerable wear due to the tremendous impact forces encountered during normal operating conditions, and therefore must be periodically replaced. To facilitate replacement and to reduce inventory requirements for spare blow bar parts, a number of current impact crusher designs provide for segmented blow bars, that is, shorter blow bar lengths that may require two or more blow bar segments installed end-to-end to span the length of the rotor bar body. The shorter blow bar segments are easier to remove than one large blow bar that extends the entire length of the rotor body. At the same time, blow bar segments of a single, uniform size can be carried in inventory for use with different sized machines and rotor assemblies. 
     One known method of replaceably mounting blow bars to a horizontal impact crusher rotor assembly is to use a wedge seating arrangement wherein the blow bars are caused to wedge in place against wedge surfaces associated with the body of the rotor assembly by centrifugal forces exerted on the blow bars as they rotate at high speeds. One such wedge seating arrangement is described in U.S. Pat. No. 4,679,740 issued to Axel O. Orphall wherein the blow bars are held in wedge slots formed in the perimeter of a series of disk plates radially extending from the rotor shaft, so that the blow bars are gripped only at discreet wedge locations. Such a wedge seating arrangement, however, cannot readily accommodate the advantageous use of segmented blow bars due to the limited area of contact between the blow bars and the disc plate wedges and due to the lack of structural integrity that would result from such an assembled unit. The point contacts also lead to increased stress on the blow bars and rotor assembly resulting in excessive wear and blow bar breakage and increased down time replacement costs. 
     Another disadvantage with existing blow bar mounting arrangements is the inability of the mounting slots to accommodate blow bars having different thicknesses. Also, wear on the backer wall structure of the mounting slots typically requires that the backer wall structure be periodically machined or rebuilt. Machining operations are costly and time-consuming and the need for different sized wedges increases inventory costs. 
     The present invention provides an improved rotor assembly for a horizontal impact crusher which provides the advantage of a wedge type mounting system for the blow bars while overcoming the aforementioned disadvantages of existing wedge mounting systems. The present invention also provides a means for wedge mounting segmented blow bars to the rotor body while providing a structurally sound wedge system that will hold up to the rugged operating environment of the rotor assembly. Further provided is a means for mounting blow bars of different thicknesses with the same wedge mounting system, as well as a means for eliminating the need to periodically machine or rebuild the wedge slot&#39;s backer wall structure. 
     SUMMARY OF THE INVENTION 
     The invention is an improved rotor assembly comprised of a rotor body having an outer perimeter and at least two wedge slots in the perimeter of the rotor body parallel to the rotor&#39;s axis. Each wedge slot is a continuous wedge slot which preferably extends from one end of the rotor body to the other and which has a defined width, a wedge seat sloping inwardly in relation to the rotor&#39;s perimeter, and a backer wall opposed to the wedge seat. A segmented floating blow bar is removably inserted into each wedge slot between the slot&#39;s wedge seat and its backer wall structure. Floating wedge means are, in turn, inserted between the blow bar and the slot&#39;s wedge seat such that the blow bar is wedged in place by centrifugal forces imparted to the blow bar and wedge structure during high speed rotation of the rotor assembly. The floating wedge means provides a continuous wedge structure which overlaps the joint or joints formed between blow bar segments so as to structurally tie the blow bar segments together. The blow bar wedge means can also be segmented in such a manner that the joints between segmented wedge elements are displaced relative to the blow bar segment joints. 
     In another aspect of the invention, a backer face plate is provided on the side of the blow bar opposite the blow bar wedge means, that is, between the blow bar and the wedge slot&#39;s backer wall. Backer face plates can be provided in different thicknesses to adjust the width of the wedge slots to accommodate blow bars of different thicknesses, and act as wear elements that can be periodically replaced instead of having to machine or rebuild the backer wall. 
     Therefore, it is a primary object of the present invention to provide an improved rotor assembly for a horizontal impact crusher which permits segmented blow bars to be mounted to the rotor assembly by means of a wedge mounting system. It is another object of the invention to provide an improved rotor assembly wherein the segmented blow bar and wedge elements interlock to provide a structurally sound wedge mounting arrangement that can withstand the rugged operating environment of the rotor assembly. It is a further object of the invention to provide a rotor assembly wherein the blow bars are easily replaced and wherein the need to inventory different sized blow bars is reduced or eliminated. Still another object of the invention is to reduce the need for machine maintenance and repair and associated down time. Other objects of the invention will become apparent from the following specification and claims, together with the accompanying drawings. 
    
    
     DESCRIPTION OF THE DRAWINGS 
     FIG. 1 is a cross-sectional view, in side elevation, of a horizontal impact crusher having an improved rotor assembly in accordance with the invention. 
     FIG. 2 is an enlarged top perspective view of the improved rotor assembly of the horizontal impact crusher shown in FIG. 1. 
     FIG. 3 is an enlarged fragmentary view, in side elevation, of the rotor assembly of FIG. 2, showing the wedge mounting of the blow bars in the perimeter of the rotor body. 
     FIG. 4 is an exploded view of the rotor assembly of FIG. 2. 
     FIGS. 5 and 5A are graphical representations of the interlocking blow bar wedge system of the invention. 
    
    
     DETAILED DESCRIPTION OF THE ILLUSTRATED EMBODIMENT 
     Referring now to the drawings, FIG. 1 shows the general configuration of a horizontal impact crusher, depicted by the numeral 11, wherein a crusher frame 13 houses hydraulically adjustable curtain assemblies 15, 17, a bottom stationary curtain assembly 19, and rotor assembly 21. In a manner well-known in the art, crushable material that is fed into crusher 11 through feed opening 12 is propelled against liner plates 15a, 17a, 19a of the adjustable and stationary curtain assemblies as the rotor assembly rotates at high speeds, such that, the impact of the crushable material striking the curtain assemblies generates the desired crushing forces. Stripper bars 25 provide a sized opening 27 between the rotor assembly 21 and the crusher frame 13 to insure that all material fed into the crusher is engaged by the rotor assembly. 
     Referring to FIG. 2, the crusher&#39;s rotor assembly 21 is shown as having a rotor body 29 secured to drive shaft 31 which rotates about rotor axis 32, with the assembly&#39;s four floating blow bars 23 being mounted to the rotor body&#39;s outer perimeter 33 at equally spaced 90° intervals. It can be seen that the length of the rotor body along the rotor axis is generally defined by the rotor end walls 35, 37. It can also be seen that blow bars 23 provide a continuous floating blow bar structure that spans this entire length of the rotor, and in fact projects somewhat beyond the rotor end walls. The length of the blow bars are generally chosen to occupy the width of the housing frame 13 in order to prevent crushable material from falling through the ends of the rotor assembly. 
     Each blow bar 23 is comprised of three separate blow bar segments, 23a, 23b, 23c, which, as best shown in FIG. 3, are mounted in an end-to-end abutting relation in a generally V-shaped wedge slot 39 having a width that is greater than the thickness of the blow bar segments. A wedge shoe 41 is welded into the side of the wedge slot to provide a wedge seat 43 that slopes inwardly toward the outer perimeter of the rotor body. Replaceable wear plate 49 attached to the top of the wedge shoe extends wedge seat 43 and provides a serviceable wear surface for a floating wedge means. 
     The assembly&#39;s wedge means, like the blow bars, are comprised of segmented elements, namely, floating wedge segments 47a, 47b, 47c (see FIGS. 2, 4, and 5). These wedge segments fit into the wedging space 45 of the wedge slot in end-to-end abutting relation, such that, a continuous wedge structure is provided which interlocks with the blow bar segments as described in greater detail below. End plates 53 removably attached at the edge of the wedge slots at each end of the rotor body hold the wedge and blow bar structure in place. 
     Each of the rotor&#39;s wedge slots also includes a backer wall 55 which opposes the slot&#39;s wedge seat 43. Backer wall face plates 57 removably attach to the backer wall by suitable screw attachments as shown in FIG. 4, and provide a means to size the wedge slot to accommodate blow bars of a given thickness. As noted above, the backer wall face plates also protect the backer wall eliminating the need for costly repair work in this region of high wear. FIG. 4 also shows the use of anti-shift pins 59 inserted through the backer wall to prevent lateral movement of the blow bar in the wedge slot when the crusher is operating. 
     With reference to FIGS. 4 and 5, it can be seen that a blow bar wedge assembly 24 associated with each wedge slot is formed by interlocking elements which, for reasons of structural integrity, have no overlapping joints. Specifically, joints 61, 62 of blow bar segments 23a, 23b, 23c are laterally displaced from joints 63, 64 of wedge segments 47a, 47b, 47c. Similarly, the joint 67 of wedge wear plate segments 49a, 49b is positioned between wedge joints 63, 64, while joint 69 of backer wall face plate segments 57a, 57b is located between blow bar joints 61, 62. The overlapping joint structure of this blow bar wedge assembly is diagrammatically illustrated in FIGS. 5 and 5A which show a stack of segmented elements--plus backer wall 55 which is not segmented--with the segment joints of each element in the stack being located over the structure of one of the adjacent elements in the stack. The overlapping elements form an interlocking, highly durable structure that is easily assembled and disassembled. 
     Each blow bar wedge assembly 24 is easily assembled and disassembled in their respective wedge slots 39 as follows: To assemble the blow bar assembly, a backer face plate 57 of a suitable thickness to accommodate a desired blow bar is attached to the wedge slot&#39;s backer wall 55. The segments of blow bar 23 are then dropped into the wedge slot, after which the segments of wedge 47 are installed by sliding them into wedging space 45 from the end of the rotor. Finally, wear plate segments 49a, 49b are fastened to the top of the wedge shoe by suitable screw attachments as shown in FIG. 4, and end plates 53 secured at each end of the wedge slot to hold the resulting blow bar and wedge structure in place. It is noted that the blow bar is a symmetric element, thus when one of the blow bar tips 26 wears down, the blow bar can be reversed in the wedge slot to make use of the opposite tip. It is also noted that each blow bar 23 and its corresponding wedge 47 are locked together by means of a locking rib 48 on the back face of wedge which fits into a corresponding locking groove 50 machined into face of the blow bar. 
     The blow bar and wedge assembly above described is sized to fit loosely within the wedge slot until the rotor assembly is driven into rotation, whereupon centrifugal forces wedge the blow bar and wedge structure into place against wedge seat 53. To replace the blow bars, the blow bars simply need to be struck by a hammer or other suitable instrument to break the wedge assembly loose from the wedge seat. The end caps 53 can then be removed to permit the wedges to first be slid out of the wedge slot, after which the heavier blow bars can be lifted out. 
     Therefore, it can be seen that the present invention provides for an improved rotor assembly for a horizontal impact crusher which employs an improved wedging system for holding segmented blow bars onto the body of the rotor assembly. The invention provides a rotor assembly having a high degree of structural strength and which is easily assembled and disassembled for blow bar repair and replacement. While the invention has been described in considerable detail in the foregoing specification and accompanying drawings, it is understood that it is not intended that the invention be limited to such detail, except as necessitated by the following claims.