Patent Publication Number: US-7712693-B2

Title: Degradation insert with overhang

Description:
CROSS REFERENCE TO RELATED APPLICATIONS 
   This application is a continuation of U.S. patent application Ser. No. 12/051,689 filed on Mar. 19, 2008 which is a continuation-in-part of U.S. patent application Ser. No. 12/051,586 filed on Mar. 19, 2008 which is a continuation of U.S. patent application Ser. No. 12/021,051 filed on Jan. 28, 2008 which is a continuation-in-part of U.S. patent application Ser. No. 12/021,019 filed on Jan. 28, 2008 which was a continuation-in-part of U.S. patent application Ser. No. 11/971,965 filed on Jan. 10, 2008 now U.S. Pat. No. 7,648,210 which is a continuation of U.S. patent application Ser. No. 11/947,644, filed on Nov. 29, 2007 which was a continuation-in-part of U.S. patent application Ser. No. 11/844,586 filed on Aug. 24, 2007 now U.S. Pat. No. 7,600,823 U.S. patent application Ser. No. 11/844,586 is a continuation-in-part of U.S. patent application Ser. No. 11/829,761 filed on Jul. 27, 2007 U.S. patent application Ser. No. 11/829,761 is a continuation-in-part of U.S. patent application Ser. No. 11/773,271 filed on Jul. 3, 2007 U.S. patent application Ser. No. 11/773,271 is a continuation-in-part of U.S. patent application Ser. No. 11/766,903 filed on Jun. 22, 2007 U.S. patent application Ser. No. 11/766,903 is a continuation of U.S. patent application Ser. No. 11/766,865 filed on Jun. 22, 2007 U.S. patent application Ser. No. 11/766,865 is a continuation-in-part of U.S. patent application Ser. No. 11/742,304 filed on Apr. 30, 2007 now U.S. Pat. No. 7,475,948 U.S. patent application Ser. No. 11/742,304 is a continuation of U.S. patent application Ser. No. 11/742,261 filed on Apr. 30, 2007 now U.S. Pat No. 7,469,971 U.S. patent application Ser. No. 11/742,261 is a continuation-in-part of U.S. patent application Ser. No. 11/464,008 filed on Aug. 11, 2006 now U.S. Pat. No. 7,338,135 U.S. patent application Ser. No. 11/464,008 is a continuation-in-part of U.S. patent application Ser. No. 11/463,998 filed on Aug. 11, 2006 now U.S. Pat. No. 7,384,105 U.S. patent application Ser. No. 11/463,998 is a continuation-in-part of U.S. patent application Ser. No. 11/463,990 filed on Aug. 11, 2006 now U.S. Pat. No. 7,320,505 U.S. patent application Ser. No. 11/463,990 is a continuation-in-part of U.S. patent application Ser. No. 11/463,975 Filed on Aug. 11, 2006 now U.S. Pat. No. 7,445,294 U.S. patent application Ser. No. 11/463,975 is a continuation-in-part of U.S. patent application Ser. No. 11/463,962 filed on Aug. 11, 2006 now U.S. Pat No. 7,413,256 U.S. patent application Ser. No. 11/463,962 is a continuation-in-part of U.S. patent application Ser. No. 11/463,953 filed on Aug. 11, 2006 now U.S. Pat. No. 7,464,993 The present application is also a continuation-in-part of U.S. patent application Ser. No. 11/695,672, filed Apr. 3, 2007, now U.S. Pat. No. 7,396,086. U.S. patent application Ser. No. 11/695,672 is a continuation-in-part of U.S. patent application Ser. No. 11/686,831 filed on Mar. 15, 2007 now U.S. Pat. No. 7,568,770. All of these applications are herein incorporated by reference for all that they contain. Also U.S. patent application Ser. No. 11/561,827 which is a continuation-in-part of U.S. patent application Ser. No. 11/424,833 and U.S. patent application Ser. No. 11/426,202 is a continuation-in-part of U.S. patent application Ser. No. 11/426,202. These references are also herein incorporated by reference for all that they disclose. 

   BACKGROUND OF THE INVENTION 
   Replaceable wear liners are often incorporated into cone crushers to form the crushing surfaces used to crush various materials. Cone crushers typically comprise of an assembly that rotates about a stationary shaft resulting in a gyratory motion which is harnessed to crush material as it traverses between crushing surfaces in the crushing chamber where the replaceable wear liners are located. Material to be crushed is effectively reduced into smaller dimensions as a result of being subjected to compression between the tapered crushing surfaces of the crushing chamber. The reduced material then exits from a gap between the crushing surfaces sometimes called the “closed side setting” where the minimum width of the reduced material is predetermined by manipulating the closed side setting in accordance with the desired geometry of the reduced material. The final product consists of material that possesses the desired geometry or ratio of length to width to thickness for various applications such as road surfacing, paving, landscaping and so forth. 
   Over time the replaceable wear liner may begin to deteriorate such that the space between the crushing surfaces become distorted which consequently reduces the crushers ability to produce the desired geometry resulting in irregular or substandard final product material. Substandard product may require that the replaceable wear liner be serviced or replaced. Consequently, the time required to properly address wear issues equates to significant economic loss both in terms of maintenance and production loss. 
   In the prior art, U.S. Pat. Nos. 5,967,431 and 6,123,279 as well as U.S. Patent Publication Nos. 2003/0136865, 2008/0041994 and 2008/0041995 are herein incorporated by reference for all that they contain which disclose cone crushers that may be compatible with the present invention. U.S. Patent Publication No. 2008/0041992 and 2008/0041993 are also incorporated by reference for all that they contain. 
   BRIEF SUMMARY OF THE INVENTION 
   In one aspect of the invention, a cone crusher has at least one crushing surface disposed on either a cone and/or an inverted bowl of the crusher. The crushing surface has at least one insert having an impact head with a stem protruding from a base end of the head. The stem has a smaller cross sectional thickness than the head. 
   The stem and head may be made from the same material. The stem and head may be made of two dissimilar materials. The material of the stem may have a coefficient of thermal expansion greater than a coefficient of thermal expansion of the material of the head. A material of the stem may have a coefficient of thermal expansion equal to or greater than a coefficient of thermal expansion of a material of the cavity. 
   The base end of the head may be adapted to protect a region of the crushing surface proximate the stem. A cavity formed in the crushing surface may have a seat complimentary to the base end of the head. The stem may be press-fit into a cavity formed in the crushing surface. The insert may be threaded into a cavity formed in the crushing surface. 
   A plurality of inserts may be packed in proximity to each other on the crushing surface. The insert may have at least one flat to accommodate packing. An overhang formed by the base end of the insert may contact the crushing surface. 
   The stem and head may be interlocked. The stem may have a collar at a second end of the stem adapted to be press-fitted within a cavity formed in the crushing surface. The head may have a recess formed in its base end and is adapted to interlock with the stem. The stem may have a locking mechanism adapted to interlock a first end of the stem within the recess. The locking mechanism may have a radially extending catch formed in the first end of the stem. The cavity may have an inwardly protruding catch. The inwardly protruding catch may be adapted to interlock with the radially extending catch. A snap ring may be intermediate the inwardly protruding catch and the radially extending catch. A locking fixture may be disposed within a cavity formed in the crushing surface and locks the stem to a wall of the cavity. The base end of the head may have an upward extending taper. The impact head may have a plurality of layered materials. 
   A crusher may have at least one crushing surface. The crushing surface may have at least one insert having an impact head with a stem protruding from a base end of the head. The stem may have a smaller cross sectional thickness than the head. 

   
     BRIEF DESCRIPTION OF THE DRAWINGS 
       FIG. 1  is a perspective cross-sectional diagram of an embodiment of a cone crusher with a replaceable wear liner. 
       FIG. 2  is top perspective diagram of an embodiment of a conical head replaceable wear liner. 
       FIG. 3  is top perspective diagram of an embodiment of a concave bowl replaceable wear liner. 
       FIG. 4  is top perspective diagram of another embodiment of a conical head replaceable wear liner. 
       FIG. 5  is a cross-sectional diagram of an embodiment of an insert. 
       FIG. 6  is a cross-sectional diagram of another embodiment of an insert. 
       FIG. 7  is a cross-sectional diagram of another embodiment of an insert. 
       FIG. 8  is a cross-sectional diagram of another embodiment of an insert. 
       FIG. 9  is a cross-sectional diagram of another embodiment of an insert. 
       FIG. 10  is a cross-sectional diagram of another embodiment of an insert. 
       FIG. 11  is a cross-sectional diagram of another embodiment of an insert. 
       FIG. 12  is a cross-sectional diagram of another embodiment of an insert. 
       FIG. 13  is top perspective diagram of an embodiment of a plurality of packed inserts. 
       FIG. 14  is top perspective diagram of another embodiment of a plurality of packed inserts. 
       FIG. 15  is top perspective diagram of another embodiment of a plurality of packed inserts. 
       FIG. 16  is top perspective diagram of another embodiment of a plurality of packed inserts. 
       FIG. 17  is top perspective diagram of another embodiment of a plurality of packed inserts. 
       FIG. 18  is top perspective diagram of another embodiment of a plurality of packed inserts. 
       FIG. 19  is a perspective sectional diagram of an embodiment of a jaw crusher in accordance with the present invention. 
       FIG. 20  is a perspective cross-sectional diagram of an embodiment of a hammer mill in accordance with the present invention. 
       FIG. 21  is a perspective diagram of an embodiment of a hammer. 
       FIG. 22  is a cross-sectional diagram of another embodiment of a hammer. 
       FIG. 23  is a cross-sectional diagram of another embodiment of a hammer. 
       FIG. 24  is a cross-sectional diagram of another embodiment of a hammer. 
       FIG. 25  is a cross-sectional diagram of another embodiment of a hammer. 
       FIG. 26  is a cross-sectional diagram of another embodiment of a hammer. 
       FIG. 27  is a cross-sectional diagram of another embodiment of a hammer. 
       FIG. 28  is a cross-sectional diagram of another embodiment of a hammer. 
   

   DETAILED DESCRIPTION OF THE INVENTION AND THE PREFERRED EMBODIMENT 
     FIG. 1  depicts a cone crusher  100  in accordance with the present invention. The cone crusher  100  may comprise at least one disposable replaceable wear liner  115  configured for either a conical head  105  or a concave bowl  110 . The concave bowl  110  is typically connected to a hopper for receiving aggregate such as rock. The conical head  105  and concave bowl  110  may each comprise replaceable wear liners  115  comprised of a material selected from the group consisting of manganese, steel, stainless steel, carbide, and combinations thereof, which form the crushing surfaces  120  of the crushing chamber  125 . Inserts are incorporated into the wear liner and may serve to enhance resistance to wear and may assist to prolong the life of the replaceable wear liner  115 . The inserts may also be used to break the aggregate passing through the crusher such that the aggregate is preferentially shaped. In some embodiments the inserts comprise carbide, a cemented metal carbide, diamond, vapor deposited diamond, sintered diamond, hardened steel, cubic boron nitride, manganese, ceramics, silicon carbide, and combinations thereof. The crushing surface  120  of the replaceable wear liner  115  may also comprise of a plurality of cavities  135  which are formed to accept the inserts  140 . The inserts  140  may be incorporated in at least one of the replaceable wear liners  115  extending from one crushing surface  120  towards another opposing crushing surface  120  and may be disposed in such a way to provide optimal disintegration of crushing material while also providing enhanced wear resistance for the replaceable wear liner  115 . The inserts  140  may be brazed or press fit within the cavities  135 . The inserts  140  may protrude out of the crushing surface  120  at a range between 0.100 to 3.00 inches depending on the material to be reduced. In some embodiments the inserts  140  do not protrude at all from the crushing surface  120  but are flush or retracted within the cavity  135 . The diameter of the inserts  140  may range from 3 mm to 19 mm. 
   The inserts  114  may be populated over the entire surface area of either the conical head  105  or the concave bowl  110 . In some embodiments, only areas susceptible to high wear are populated. 
     FIG. 2  is another embodiment of a cone crusher  100  depicting a replaceable wear liner  115  of a conical head  105  where the arrangement of inserts  140  are disposed in circular rows around the lower portion of the replaceable wear liner  115 .  FIG. 3  is an embodiment of a replaceable wear liner  115  of a concave bowl  105  depicting the arrangement of inserts  140  also being disposed in circular rows around the lower portion of the replaceable wear liner  115 . The rows may align with each other or the rows may be offset from one another. In some embodiments, the lower rows may comprise more inserts  140  than the upper rows. The preferred embodiment is to have the inserts  140  disposed within the lower peripheral circumference of the replaceable wear liner  115  of conical head  105  where the liner is most susceptible to wear. This preferred embodiment may assist to counter the erosive deterioration of the replaceable wear liner and improve consistency of the geometry of the size reduced aggregate. Yet in other embodiments it may also be advantageous to have the inserts  140  disposed within the upper portions of the replaceable wear liner  115  of both the conical head  105  and concave bowl  110  or combinations thereof.  FIG. 4  discloses an embodiment of a replaceable wear liner  115  of a conical head  105  where the arrangement of inserts  140  are disposed in circular rows around the lower portion and the upper portion of the replaceable wear liner  115 . 
   Referring now to  FIGS. 5 through 6 , the insert  140  comprises an impact head  504  with a stem  501  protruding from a base end  505  of the head  504 . The stem  501  may be press fit into the cavity  135 . The stem  501  may be retained within the cavity  135  by a braze. The stem  501  comprises a smaller cross sectional thickness  502  than a cross sectional thickness  503  of the head  504  causing an overhang  507  to be formed by the base end  505  of the head  504 . It is believed that the overhang  507  in the base end  505  of the head  504  will protect a region of the crushing surface  120  proximate the stem  501 . In the prior art, inserts incorporated in cone crushers are susceptible to failure since the inserts fall out when the crushing surface immediately proximate to them wear away leaving the inserts little or no support. Since the overhang protects the volume of the crushing surface which supports the inserts, the inserts will remain in the crushing surface longer and such that they will continue to protect the crushing surface longer and enable the aggregate to be crushed preferentially as well. The region of the crushing surface  120  proximate the stem  501  may include at least all of the material of the replaceable wear liner  115  directly below the overhang  507 . The base end  505  of the head  504  may comprise an upward extending taper. The cavity  135  may comprise a seat  506  complimentary to the base end  505  of the head  504 . It is believed that the base end  505  with the upward extending taper and the complimentary seat  506  will provide side support to the insert  140  and preferentially distribute impact forces as the insert  140  contacts the aggregate. 
   In some embodiments, the cross-sectional thickness of the head is at least twice the thickness of the stem. In some embodiments the cross-sectional thicknesses are diameters. 
   The stem  501  and head  504  may be made from the same material and may be formed from a single piece of material. The stem  501  and head  504  also may be made of two dissimilar materials. In the case of the head  504  and stem  501  being made from two dissimilar materials, the material of the stem  501  may have a coefficient of thermal expansion greater than a coefficient of thermal expansion of the material of the head  504 . The material of the stem  501  may have a coefficient of thermal expansion equal to or greater than a coefficient of thermal expansion of a material of the cavity  135 . It is believed that if the coefficient of thermal expansion of the stem  501  material is equal to or greater than the coefficient of thermal expansion of the cavity  135  material that a press fit connection between the stem  501  and the cavity  135  will not be compromised as the replaceable wear liner  115  increases in temperature due to friction or working conditions. This is also solves another problem of the prior when inserts fall out of the crushing surface as the crushing surface (which has a greater coefficient of thermal expansion) increases more than the inserts and thereby allow the inserts to fall out. In the preferred embodiment, the coefficients of thermal expansion between the stem and the crushing surface are within 10 percent. In some embodiments, if the coefficients of thermal expansion are more then 50 percent the stems  501  may loose their press fit and potentially fall out of the cavities  135 . The benefits of similar coefficients allow for a more optimized press fit. 
   The head  504  comprises a working surface  508  with a generally conical geometry  509 . The head  504  may also comprise a plurality of layered materials  601 . The plurality of layered materials  601  may comprise a diamond layer  602  bonded to a cemented metal carbide substrate layer  603 . The diamond layer  602  comprises a volume greater than a volume of the carbide substrate layer  603 . In some embodiments the diamond layer  602  may comprise a volume that is 75% to 175% of a volume of the carbide substrate layer  603 . The diamond layer  602  may be a material selected from the group consisting of diamond, polycrystalline diamond, natural diamond, synthetic diamond, vapor deposited diamond, silicon bonded diamond, cobalt bonded diamond, thermally stable diamond, polycrystalline diamond with a binder concentration of 1 to 40 weight percent, infiltrated diamond, layered diamond, monolithic diamond, polished diamond, course diamond, fine diamond, cubic boron nitride, diamond impregnated matrix, diamond impregnated carbide, metal catalyzed diamond, or combinations thereof. The diamond layer  602  may be bonded to a carbide substrate which may in turn be bonded to the head of the insert. The diamond layer may be between 0.100 and 0.400 inches thick, preferably between 0.150 and 0.275 inches thick. The substrate by between 20 and 2 mm thick. The diamond layer  602  may comprise an average diamond grain size of 1 to 100 microns. 
   The diamond layer  602  comprises a substantially conical geometry with an apex. Preferably, the interface between the substrate layer  603  and the diamond layer  602  is non-planar, which may help distribute loads on the plurality of layered materials  601  across a larger area of the interface. 
   Referring now to  FIGS. 7 through 10 , the overhang  507  overhang formed by the base end  505  of the head  504  may contact the crushing surface  120 . The stem  501  and cavity  135  may also be threaded  801  so that the insert  140  may be threaded into the cavity  135 . The working surface  508  of the head  504  may comprise generally hemispherical geometry  901 . At least one of the inserts  140  may be mounted in the replaceable wear liners  115  such that a central axis  1001  of the insert  140  and the crushing surface  120  form an angle  1002  greater than or less than 90 degrees. 
   Referring now to  FIG. 11 , the insert  140  may comprise the head  504  and a stem assembly  1101  comprising a first end  1102  and a second end  1103 . The head  504  is adapted to interlock with the stem assembly  1101 . The first end  1102  of the stem assembly  1101  may be adapted to fit into a recess  1104  formed in the base end  505  of the head  504 . In  FIG. 11  the stem assembly  1101  is generally cylindrical. The second end  1103  of the stem assembly  1101  is press-fitted into the cavity  135  of the replaceable wear liner  115 . 
   The stem assembly  1101  may comprise a hard material such as steel, stainless steel, hardened steel, or other materials of similar hardness. The head  504  may comprise tungsten, titanium, tantalum, molybdenum, niobium, cobalt and/or combinations thereof. 
   The stem assembly  1101  may be work-hardened or cold-worked in order to provide resistance to cracking or stress fractures due to forces exerted on the insert  140  by the crushing material. The stem assembly  1101  may be work-hardened by shot-peening or by other methods of work-hardening. At least a portion of the stem assembly  1101  may also be work-hardened by stretching it during the manufacturing process. In some embodiments, the stem assembly may be tensioned. 
   The stem assembly  1101  comprises a locking mechanism  1112  and a collar  1106 . The locking mechanism  1112  is axially disposed within a bore  1107  of the collar  1106  and the second end  1103  of the locking mechanism  1112  is secured within or below the bore  1107 . The first end  1102  of the locking mechanism  1112  protrudes into the recess  1104  in the base end  505  of the head  504  and the first end  1102  of the collar  1106  may be adapted to fit into the recess  1104  in the base end  505  of the head  504 . The locking mechanism  1112  is adapted to lock the first end  1102  of the stem assembly  1101  within the recess  1104 . The locking mechanism  1112  may attach the stem assembly  1101  to the head  504  and restrict movement of the stem assembly  1101  with respect to the head  504 . The locking mechanism  1112  comprises a radially extending catch  1119  that is formed in the first end  1102  of the stem assembly  1101 . The stem assembly  1101  may be prevented by the locking mechanism  1112  from moving in a direction parallel to the central axis  1001  of the insert  140 . In some embodiments the stem assembly  1101  may be prevented by the locking mechanism  1112  from rotating about the central axis  1001 . 
   The recess  1104  may comprise an inwardly protruding catch  1118 . A snap ring  1120  is disposed intermediate the inwardly protruding catch  1118  of the recess  1104  and the radially extending catch  1119  of the first end  1102  of the locking mechanism  1112 . In some embodiments the snap ring  1120  is a flexible ring  1120 . In some embodiments the snap ring  1120  may be a split ring, coiled ring, a flexible ring or combinations thereof. In  FIG. 11  the locking mechanism  1112  comprises a locking shaft  1105 . The locking shaft  1105  is connected to an expanded locking head  1113 . In some embodiments the radially extending catch  1119  is an undercut formed in the locking head  1113 . The snap ring  1120  and locking head  1113  are disposed within the recess  1104  of the head  504 . The locking shaft  1105  protrudes from the recess  1104  and into an inner diameter  1108  of the stem assembly  1101 . The locking shaft  1105  is disposed proximate the bore  1107  proximate the first end  1102  of the stem assembly  1101 . The locking shaft  1105  is adapted for translation in a direction parallel to the central axis  1001  of the stem assembly  1101 . The locking shaft  1105  may extend from the recess  1104  and the snap ring  1120  may be inserted into the recess  1104 . 
   When the first end  1102  of the locking mechanism  1112  is inserted into the recess  1104 , the locking head  1113  may be extended away from the bore  1107  of the collar  1106 . The snap ring  1120  may be disposed around the locking shaft  1105  and be intermediate the locking head  1113  and the bore  1107 . The snap ring  1120  may comprise stainless steel. In some embodiments the snap ring  1120  may comprise an elastomeric material and may be flexible. The snap ring  1120  may be segments, balls, wedges, shims, a spring or combinations thereof. 
   The snap ring  1120  may comprise a breadth  1115  that is larger than an opening  1114  of the recess  1104 . In such embodiments the snap ring  1120  may compress to have a smaller breadth  1115  than the opening  1114 . Once the snap ring  1120  is past the opening  1114 , the snap ring  1120  may expand to comprise its original or substantially original breadth  1115 . With both the snap ring  1120  and the locking head  1113  inside the recess  1104 , the rest of the first end  1102  of the stem assembly  1101  may be inserted into the recess  1104  of the head  504 . Once the entire first end  1102  of the stem assembly  1101  is inserted into the recess  1104  to a desired depth, a nut  1111  may be threaded onto an exposed end  1109  of the locking shaft  1105  until the nut  1111  contacts a ledge  1110  proximate the bore  1107  mechanically connecting the locking mechanism  1112  to the collar  1106 . This contact and further threading of the nut  1111  on the locking shaft  1105  may cause the locking shaft  1105  to move toward the second end  1103  of the stem assembly  1101  in a direction parallel to the central axis  1001  of the stem assembly  1101 . This may also result in bringing the radially extending catch  1119  of the locking head  1113  into contact with the snap ring  1120 , and bringing the snap ring  1120  into contact with the inwardly protruding catch  1118  of the recess  1104 . The nut  1111  is an embodiment of a tensioning mechanism  1117 . The tensioning mechanism  1117  is adapted to apply a rearward force on the first end  1102  of the stem assembly  1101 . The rearward force may pull the first end  1102  of the stem assembly  1101  in the direction of the second end  1103  and applies tension along a length of the locking shaft  1105 . In some embodiments the tensioning mechanism  1117  may comprise a press fit, a taper, and/or a nut  1111 . 
   Once the nut  1111  is threaded tightly onto the locking shaft  1105 , the locking head  1113  and snap ring  1120  are together too wide to exit the opening  1114 . In some embodiments the contact between the locking head  1113  and the head  504  via the snap ring  1120  may be sufficient to prevent both rotation of the stem assembly  1101  about its central axis  1001  and movement of the stem assembly  1101  in a direction parallel to its central axis  1001 . In some embodiments the locking mechanism  1112  is also adapted to inducibly release the stem assembly  1101  from attachment with the head  504  by removing the nut  1111  from the locking shaft  1105 . 
   The snap ring  1120  may comprise stainless steel and may be deformed by the pressure of the locking head  1113  being pulled towards the second end  1103  of the stem assembly  1101 . As the snap ring  1120  deforms it may become harder. The deformation may also cause the snap ring  1120  to be complementary to both the inwardly protruding catch  1118  and the radially extending catch  1119 . This dually complementary snap ring  1120  may avoid point loading or uneven loading, thereby equally distributing contact stresses. In such embodiments the snap ring  1120  may be inserted when it is comparatively soft, and then may be work hardened while in place proximate the catches  1118 ,  1119 . 
   In some embodiments at least part of the stem assembly  1101  of the insert  140  may also be cold worked. The locking mechanism  1112  may be stretched to a critical point just before the strength of the locking mechanism  1112  is compromised. In some embodiments, the locking shaft  1105 , locking head  1113 , and snap ring  1120  may all be cold worked by tightening the nut  1111  until the locking shaft and head  1105 ,  1113 , and the snap ring  1120 , reach a stretching critical point. During this stretching the snap ring  1120 , and the locking shaft and head  1105 ,  1113 , may all deform to create a complementary engagement, and may then be hardened in that complementary engagement. In some embodiments the complementary engagement may result in an interlocking between the radially extending catch  1119  and the inwardly protruding catch  1118 . 
   In the embodiment of  FIG. 11 , both the inwardly protruding catch  1118  and the radially extending catch  1119  are tapers. Also in  FIG. 11 , the base end  505  of the head  504  comprises a uniform inward taper  1116 . 
   Referring now to  FIG. 12 , the collar  1106  may comprise a spacer  1203  and a locking fixture  1201 . The locking fixture  1201  may be disposed proximate the second end  1103  of the stem assembly and around and connected to the locking shaft  1105 . The spacer  1203  is disposed intermediate the locking fixture  1201  and the head  504  and around the locking shaft  1105 . A meltable ring  1204  may be disposed intermediate the spacer  1203  and the head  504 . The locking fixture  1201  may comprise barbs  1202 . When the insert  140  is placed with in the cavity  135 , the barbs  1202  of the locking fixture  1201  will dig into the side walls of the cavity  135  retaining the insert  140  within the cavity  135 . The insert  140  may be heated such that the meltable ring  1204  melts. The melting ring  1204  may deform to a smaller thickness allowing the locking fixture  1201  to pull the head deeper into the cavity  135 . The meltable ring may be made of wax, nylon, plastic, lead, tin, and combinations thereof. 
   Referring now to  FIGS. 13  though  18 , a plurality of the inserts  140  may be packed in proximity to each other on the crushing surface  120 . The smaller cross sectional thickness  502  of the stem  501  allows for a tight packing of the inserts  140  while maintaining a means for a strong connection between the insert  140  and the replaceable wear liner  115 .  FIG. 13  discloses an embodiment of a plurality of inserts  140  where at least one insert  140  comprises a generally crescent geometry so as to accommodate tight packing with a neighboring insert  140 . At least one insert  140  may comprise at least one flat  1401  to accommodate packing such as in the embodiments of  FIGS. 14 and 15 . The inserts  140  may be packed in aligned rows such as in the embodiment of  FIG. 16 . The inserts  140  may also be packed in offset rows such as in  FIG. 17 . The inserts  140  may be packed together such that isolated portions  1601  of the crushing surface  120  are disposed amongst the packed inserts  140 . It is believed that the if the crushing surface  120  is segmented into isolated portions the crushing surface  120  will be protected by the inserts  140  from the flow of crushing material thereby prolonging the life of the crushing surface  120 . The inserts  140  may also comprise a hexagonal geometry  1801  to accommodate packing such as in the embodiment of  FIG. 18 . The inserts  140  may also comprise but are not limited to a square geometry, triangular geometry, heptagonal geometry, pentagonal geometry, octagonal geometry, or combinations thereof. 
     FIG. 19  discloses an embodiment wherein the insert  140  may be incorporated into a jaw crusher  1900 . The jaw crusher  1900  may comprise a fixed plate  1901  with a crushing surface  120  and a pivotal plate  1902  also having a crushing surface  120 . Rock or other materials are reduced as they travel down the plates  1901 ,  1902 . The inserts  140  may be fixed to the crushing surfaces  120  of the plates  1901 ,  1902  and may be in larger size as the inserts  140  get closer to the pivotal end of the pivotal plate  1902 . 
   Referring to  FIG. 20 , the inserts with a stem with a smaller cross-sectional area than its head may be incorporated into a hammer mill  2000 . The milling chamber  2001  is defined by at least one wall  2002  of a housing  2003  which supports an internal screen  2004 , which is typically cylindrical or polygonal. Within the screen  2004  a rotary assembly  2005  comprises a plurality of shafts  2006  connected to a central shaft  2007  which is in turn connected to a rotary driving mechanism (not shown). The rotary driving mechanism may be a motor typically used in the art to rotate the rotor assembly of other hammer mills. Although there are four shafts  2006  shown, two, one, or any desired number of shafts may be used. A plurality of impact hammers  2008  are longitudinally spaced and connected to each of the shafts  2006  at the hammer&#39;s proximal end  2009 . The hammers  2008  may be rigidly attached to the shafts  2006  or the hammers  2008  may be free-swinging. In some embodiments, the rotor assembly  2005  comprises just the central shaft  2007  and the impact hammers  2008  are connected to it. 
   The housing  2003  also comprises an inlet  2010  and an outlet  2011 . Typically the inlet  2010  is positioned above the rotor assembly  2007  so that gravity directs the material towards it through an opening  2012  in the screen  2004 , although the inlet  2010  may instead be disposed in one of the sides  2013  of the housing  2003 . When in the milling chamber  2001 , a material may be reduced upon contact with the impact hammers  2008 . The screen  2004  may comprise apertures (not shown) only large enough to allow the desired maximum sized particle through. Upon impact however, a distribution of particle sizes may be formed, some capable of falling through the apertures of the screen  2004  and others too large to pass through. Since the larger particle sizes may not be able pass through the apertures, they may be forced to remain within the screen  2004  and come into contact again with one of the impact hammers  2008 . The hammers  2008  may repeatably contact the material until they are sized to pass through the apertures of the screen  2004 . 
   After passage through the screen  2004  the sized reduced particles may be funneled through the outlet  2011  for collection. In other embodiments the particles may be directed towards another machine for further processing, such as when coal is the material being reduced and fine coal particles are directed towards a furnace for producing power. It may be necessary to provide low pressure in the vicinity of the outlet  2011  to remove the particles, especially the fines, through the outlet  2011 . The low pressure may be provided by a vacuum. 
   The rotor assembly  2005  may be positioned such it is substantially perpendicular to the flow of material feed into the inlet  2010 . In other embodiments, the rotor assembly  2005  may be positioned such that it is substantially parallel or diagonally disposed with respect to the flow of feed material. In some embodiments, there are multiple rotor assemblies. 
   Referring now to  FIGS. 21 and 22 , the impact hammers  2008  comprises at least one cavity  135  formed in an impact surface  2101  of the body  2015  of the impact hammer  2008  proximate a distal end  2016  of the impact hammer  2008 . The insert  140  may be brazed or press fit into the cavity  135 . The insert  140  may reduce wear of the hammer body  2015 , which is typically more extreme at the body&#39;s  2015  distal end  2016 . 
   The inserts  140  may be packed on the impacted surface  2101  of the hammer body  2015 . The smaller cross sectional thickness  502  of the stem  501  allows for packing of the inserts  140  while maintaining a means for a strong connection between the insert  140  and the hammer body  2015 . If one of the inserts  140  were to disconnect from the hammer body  2015 , the connection between the hammer body  2015  and the rest of the inserts  140  would not be compromised since the other inserts were not relying entirely on the tight packing of the inserts  140  itself for support against the forces acting on the inserts. 
   Referring now to  FIGS. 23 through 25 , the inserts may also be mounted on a distal surface  2102 , and on the corner  2303  shared by the impacted surface  2101  and the distal surface  2102 .  FIG. 24  discloses an embodiment wherein inserts  140  of varying geometries may be mounted to the hammer body  2015 . The inserts  140  may be mounted perpendicular to the impact surface  2101  and/or distal surface  2102 . The inserts  140  may also be mounted at a non-perpendicular angle to the impact surface  2101  and/or distal surface  2102 . A single row of inserts  140  may be mounted to the hammer body  2015  on the corner  2303  shared by the impacted surface  2101  and the distal surface  2102 . 
   Referring now to  FIGS. 26 through 28 , the embodiments of insert  140  disclosed in  FIGS. 11 and 12  may be mounted to the hammer body  2015   
   Other applications not shown, but that may also incorporate the present invention include rolling mills; shaft impactors; mulchers; farming and snow plows; teeth in track hoes, back hoes, excavators, shovels; swinging picks; axes; cement drill bits; milling bits; reamers; and nose cones. 
   Whereas the present invention has been described in particular relation to the drawings attached hereto, it should be understood that other and further modifications apart from those shown or suggested herein, may be made within the scope and spirit of the present invention.