[0001] Hammer

CROSS-REFERENCE TO RELATED APPLICATIONS

[0002] This application claims the benefit of U.S. Provisional Patent Application No.

61/773,327 filed March 6, 2013 entitled "Hammer", which is incorporated by reference herein in its entirety.

BACKGROUND OF THE INVENTION

[0003] The present invention generally relates to a hammer and, in some embodiments, hammers, shanks and hammer heads used in crushing machinery.

[0004] Crushers are used for crushing various material into smaller pieces. Crushers may be used as a first step in a milling process. Crushers may be used break raw material into pieces of a defined size, which are then fed to a mill where they are milled. Crushers may also be used for material that is not to be shaped further but to be used directly, such as in the production of gravel or coal. Crushers may also be used to crush waste materials for the purpose of recycling or disposal. Examples of crushers include hammermills, impactors, breakers, sizers, granulators, Coalpactors®, roll crushers, and jaw crushers.

[0005] Among the methods to reduce the size of a material are impact, attrition, shear and compression. Most crushers employ a combination of all these crushing methods.

[0006] In crushing terminology, impact refers to the sharp, instantaneous collision of one moving object against another. Both objects may be moving, such as a baseball bat connecting with a pitched baseball, or one object may be motionless, such as a golf ball being driven off a tee.

[0007] Attrition is a term applied to the reduction of materials by scrubbing it between two hard surfaces. Hammermills operate with close clearances between the hammers and the screen bars, and they reduce the material size by attrition combined with shear and impact reduction. Though attrition consumes more power and increases wear on hammers and screen bars, it is practical for crushing less abrasive materials such as pure limestone and coal.

[0008] Shear includes a trimming or cleaving action rather than the rubbing action associated with attrition. Shearing is usually combined with other methods. For example, single-roll crushers employ shear together with impact and compression. [0009] Crushing by compression is done between two surfaces, with the work being done by one or both surfaces. Jaw crushers, for example, using this method of compression are suitable for reducing extremely hard and abrasive rock.

[0010] Some crushers utilize a closed-circuit configuration. Closed-circuit crushing is a method of controlling product size, referred to as top size, by screening the product and then returning oversized top size material to the feed end of the crusher for another pass through the machine. While it may be possible to obtain a specified top size from crushers without using a closed-circuit system, it is not always desirable. To control top size from a single crusher operating in an open circuit, material must remain in the crushing chamber until it is reduced. This can result in overcrushing a percentage of the material, with a corresponding increase in undesirably fine material and a loss of efficiency.

[0011] In a typical multiple-stage crushing plant with the last stage operated in closed-circuit, the primary crusher operates at a setting which produces a satisfactory feed size for the secondary crusher, so that a balance exists for the work done by each crusher. BRIEF SUMMARY OF THE INVENTION

[0012] In one embodiment there is a hammer comprising: a shank having a longitudinal axis, a proximal end and a distal end, the proximal end configured to couple to a rotor rotatable about an axis, and the distal end having a flared mount; a hammer head releaseably mounted to the flared mount; and one or more removeable pins extending from and at least partially through the shank, the one or more pins configured and dimensioned to prevent the hammer head from releasing from the shank when the hammer head is mounted to the flared mount.

[0013] In one embodiment, the hammer head includes a flared slot configured and dimensioned to engage the flared mount. In one embodiment, the flared slot is open through first and second lateral sides of the hammer head to permit the flared mount to slide through the flared slot. In one embodiment, the hammer head and shank are configured such that the coupling between the hammer head and the shank tightens as the hammer head moves distally relative to the shank. In one embodiment, the hammer head and shank are configured such that the hammer head does not exert an axial load on the one or more pins in operation as the hammer head moves distally relative to the shank. In one embodiment, hammer head includes a proximal edge having one or more distally extending cutouts, the one or more removable pins positioned at least partially within the one or more distally extending cutouts when the pins are engaged with the shank. [0014] In one embodiment, the one or more pins includes at least two pins and the hammer head includes a proximal edge having at least two distally extending cutouts each configured to receive one of the at least two pins. In one embodiment, the one or more removeable pins extend through the shank and extend from two opposing sides of the shank. In one embodiment, an outer boundary of the head is generally an isosceles trapezoid in a first cross section and generally a rectangle in each of two cross sections orthogonal to the first cross section. In one embodiment, the fiared mount has two faces that are generally parallel with the axis of the rotor and are oriented such that a projection of each face intersects the longitudinal axis.

[0015] In one embodiment, the flared mount includes two substantially planar surfaces configured to engage the hammer head and disposed at an angle of approximately 19 degrees relative to the longitudinal axis. In one embodiment, the hammer head is configured to be coupled to the shank in two different orientations. In one embodiment, the hammer head is symmetrical about a plane, the plane being coincident with the longitudinal axis and the axis of the rotor when the hammer head is mounted to the shank. In one embodiment, the shank is symmetrical about a plane, the plane being coincident with the longitudinal axis and the axis of the rotor.

[0016] In one embodiment, the hammer head has a hardness greater than a hardness of the shank. In one embodiment, the hammer head includes a substantially planar hammering surface that is generally parallel to a substantially planar surface of the flared mount when the hammer head is mounted to the fiared mount. In one embodiment, the flared mount has a minimum thickness of approximately one inch measured in a direction perpendicular to the longitudinal axis and the axis of the rotor. In one embodiment, the one or more pins are proximal to proximal edges of the hammer head when the hammer head is mounted to the flared mount.

[0017] In another embodiment, there is a hammer head for use in a crusher comprising: a body having first and second hammering surfaces and a longitudinal axis configured to align with a longitudinal axis of a shank when the body is mounted to the shank; a flared slot positioned between the hammering surfaces and configured to couple with a flared mount of the shank; and at least one proximal edge including one or more distally extending cutouts configured to receive one or more pins extending from the shank when the body is mounted to the shank.

[0018] In one embodiment, the flared slot is open through first and second lateral sides of the body. In one embodiment, the at least one proximal edge includes at least two distally extending cutouts each configured to receive a pin. In one embodiment, an angle between the longitudinal axis and each flared side of the flared slot is approximately 19 degrees. In one embodiment, the first and second hammering surfaces are each at an angle relative to the longitudinal axis equal to an angle between each flared side of the flared slot and the longitudinal axis.

[0019] In another embodiment, there is a a hammer head engageable with a shank, the hammer shank including a longitudinal axis and a flared mount, the hammer head comprising: a body disposed about a horizontal slot that is defined by a fiared inner surface of the body, the flared inner surface of the body being shaped and dimensioned to substantially match a shape of the flared mount, the horizontal slot being configured and dimensioned to permit the body to slide over the flared mount in a direction perpendicular to the longitudinal axis of the hammer shank, and the horizontal slot being further configured and dimensioned to permit restricted movement of the head approximately along the longitudinal axis of the hammer shank when the hammer is in use.

[0020] In one embodiment, the head has a substantially planar hammer surface a projection of which intersects the longitudinal axis of the shank when the head is operably mounted to the shank. In one embodiment, the body further comprises an outer surface having a cutout configured and dimensioned to engage a pin protruding from the shank when the head moves relative to the shank along the horizontal slot. In one embodiment, the head comprises: a first pair of the outer faces being generally parallel to each other and defining a head width that is uniform in the direction of the longitudinal axis of the shank when the head is operably mounted to the shank, and a second pair of non-parallel faces orthogonal to the first pair of outer faces, each of the second pair of faces being selectable as a hammering face. BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWINGS

[0021] The foregoing summary, as well as the following detailed description of embodiments of the hammer, will be better understood when read in conjunction with the appended drawings of an exemplary embodiment. It should be understood, however, that the invention is not limited to the precise arrangements and instrumentalities shown.

[0022] In the drawings:

[0023] Fig. 1 is a side cross sectional illustration of a crusher having a plurality of hammers in accordance with an exemplary embodiment of the present invention;

[0024] Fig. 2 is a perspective view of a hammer shown in Fig. 1 having a hammer head mounted to a shank;

[0025] Fig. 3 is a side elevational view of the hammer shown in Fig. 2;

[0026] Fig. 4 is a front elevational view of the hammer shown in Fig. 2;

[0027] Fig. 5 is a perspective view of the shank shown in Fig. 2 with the hammer head removed; [0028] Fig. 6 is a side elevational view of the shank shown in Fig. 5;

[0029] Fig. 7 is a front elevational view of the shank shown in Fig. 5;

[0030] Fig. 8 is a top perspective view of the hammer head shown in Fig. 2 with the shank removed;

[0031] Fig. 9 is a bottom perspective view of the hammer head shown in Fig. 8;

[0032] Fig. 10 is a front elevational view of the hammer head shown in Fig. 8; and

[0033] Fig. 11 is a side elevational view of the hammer head shown in Fig. 8.

DETAILED DESCRIPTION OF THE INVENTION

[0034] Referring to the drawings in detail, wherein like reference numerals indicate like elements throughout, there is shown in Figs. 1-11 a hammer, generally designated 10, in accordance with an exemplary embodiment of the present invention. Hammer 10 includes a shank 12 and a hammer head 14.

[0035] One or more hammers 10, in accordance with the embodiments shown and described herein, may be used in any desirable crusher apparatus such as a hammermill, Coalpactor® or an impactor.

[0036] Referring to Fig. 1, a cross section of an exemplary crusher 100, a hammermill, is shown having a plurality of hammers 10. During use, crusher 100 rotates a rotor 22 about rotor axis Ai to spin one or more hammers 10 about rotor axis A . As material 16 enters crusher 100, it is struck by hammers 10 that cause material 16 to fracture along its natural fault lines into smaller pieces.

Material 16, now moving at the higher velocity imparted by the swinging hammers 10, strikes stationary breaker blocks 18 radially spaced from and positioned at least partially around rotor 22, resulting in further size reduction of material 16. After striking breaker blocks 18, material 16 may then rebound into the path of the swinging hammers 10, repeating the reduction cycle until the sized material 20 exits through the bottom of crusher 100.

[0037] Referring to Figs. 1 and 2, hammer 10 is configured to be coupled to rotor 22. Shank 12 has a proximal end 12a and a distal end 12b. Proximal end 12a of shank 12 is coupled to rotor 22. In one embodiment, proximal end 12a of shank 12 is sandwiched between two plates of rotor 22. Hammer 10 may include an aperture 24 that extends through shank 12 and has a shank axis A ₂ . In one embodiment, shank axis A ₂ is generally parallel to rotor axis Ai. A fastener such as a pin may extend through aperture 24 to secure shank 12 to rotor 22. Shank 12, in some embodiments, is rotatable about shank axis A ₂ .

[0038] Referring to Fig. 3, shank 12 has a longitudinal axis A ₃ . Longitudinal axis A ₃ is generally perpendicular to shank axis A ₂ . In one embodiment, longitudinal axis A ₃ is generally perpendicular to rotor axis Ai when hammer 10 is in use. Hammer 10 may be rotatably coupled to rotor 22 to allow hammer 10 to rotate in a tangent direction relative to rotor 22, or in a hammering direction, generally perpendicular to rotor axis Ai. In other embodiments, hammer 10 is fixedly attached to rotor 22 or is attached to one or more components that are moveably attached to rotor 22. Allowing hammer 10 to move relative to rotor 22 may reduce the stress imparted on shank 12 and/or an axle that attaches shank to rotor 22 when hammer 10 impacts material 16 during use.

[0039] As used herein, the longitudinal direction is defined as a direction along longitudinal axis A ₃ , the horizontal direction is defined as a direction perpendicular to longitudinal axis A3 and generally parallel with shank axis A ₂ , and the hammering direction is defined as a direction generally perpendicular to longitudinal direction A ₃ and generally perpendicular to shank axis A ₂ . The longitudinal direction, the horizontal direction and the hammering direction each refer to when hammer head 14 is mounted to shank 12.

[0040] Referring to Fig. 1, in some embodiments, hammer 10 is configured to be used in a reversible hammermill, meaning that rotor 22 is rotatable about axis A in either hammering direction. A reversible configuration may equalize wear on the opposing faces of hammer 10 and thereby maintain each hammer 10 at maximum sharpness and crushing effectiveness as hammers 10 maintain a sharper profile, imparting a solid, direct impact to the incoming material 16. In a single direction crusher, hammers 10 may develop a rounded profile more quickly that may deliver only a glancing blow to the material, resulting in lowered capacity and increased power draw. In a reversible crusher, there is also a reduced need to pull crusher 100 out of service to manually rotate hammers 10. Reversing the direction of rotor 22 may also distribute wear equally between the two sets of breaker blocks 18.

[0041] Referring to Figs. 2-4, hammer 10 includes a shank 12 and a hammer head 14. Hardness of hammer 10 is often an important factor in determining the life of hammer 10. In one

embodiment, hammer head 14 has a hardness greater than a hardness of shank 12. In some embodiments, hammer head 14 is harder than shank 12 to reduce wear of hammer head 14 while shank 12 is more ductile than hammer head 14 in order to help absorb shock.

[0042] In one embodiment, hammer head 14 is comprised of manganese steel. In one embodiment, hammer head 14 is comprised of a white iron alloy with a high chrome content. In one embodiment, hammer head 14 is die cast. In one embodiment, hammer head 14 is heat treated. In one embodiment, hammer head 14 is cast and tempered back to a desired surface hardness. In one embodiment, hammer head 14 has a hardness of approximately 500 Brinell Hardness Number (BHN) to approximately 550 BHN. [0043] In one embodiment, shank 12 is comprised of steel. In one embodiment, shank 12 is comprised of alloy steel. In one embodiment, shank 12 is comprised of AISI 4150H. In one embodiment, shank 12 is machined. In one embodiment, shank 12 has a hardness of approximately 220 BHN to approximately 295 BHN.

[0044] Hammer head 14 may be releasably coupled to shank 12. Hammer 10 may include a two piece construction so that hammer head 14 may be replaceable, allow hammer head 14 to be flipped horizontally relative to shank 12 and/or in order to more easily provide a hammer head 14 with a greater hardness than shank 12.

[0045] Manufacturing tolerances, mold lines, thermal expansion, surface roughness and/or deformities caused by impact forces during use may result in hammer head 14 being moveable relative to shank 14 distally in the longitudinal direction. Due to the weight of hammer head 14 and the speed in which hammer head 14 is rotated by rotor 22 during use, securing hammer head 14 to shank 12 with a fastener extending through hammer head 14 and into shank 12 could, in some embodiments, result in a shear force being exerted on the fastener resulting in failure or jamming of the fastener.

[0046] Referring to Fig. 6, the mating shape between hammer head 14 and shank 12 retains the hammer head 14 to shank 12, in at least the longitudinal direction, during use. The mating shape between hammer head 14 and shank 12 allows for the hammer head 14 to be retained relative to shank 12 in the longitudinal direction without the use of additional components such as a fastener. Distal end 12b of shank 12 has a cross sectional dimension or thickness in the hammering direction that increases from a proximal portion 26d to a distal portion 26e. In one embodiment, distal portion 26e terminates at top face 26c. In one embodiment, shank 12 includes a flared mount 26 proximate distal end 12b. In one embodiment, flared mount 26 has a thickness ti in the hammering direction at distal portion 26e that is larger than a thickness t ₂ of the shank in the hammering direction at proximal portion 26d. In one embodiment, shank 12 between proximal portion 26d of flared mount 26 and proximal end 12a of shank 12 has a thickness t ₃ of approximately 2.5 inches in the hammering direction. In one embodiment, thickness t ₂ of the shank in the hammering direction at proximal portion 26d is less than the thickness t ₃ of the remainder of shank 12. Proximal portion 26d may be thinner than the remainder of shank 12 in order to accommodate hammer head 14. In other embodiments, proximal portion 26d is equal to or thicker than the remainder of shank 12.

[0047] Shank 12 and hammer head 14 may be coupled together by a sliding dovetail joint.

Flared mount 26 may act as a tenon extending in the longitudinal direction from shank 12. Flared mount 26 may increase in thickness, as measured in the hammering direction, moving distally along longitudinal axis A ₃ . The increase in thickness of flared mount 26 may be constant such that opposing faces 26a, 26b of flared mount 26 are generally planar. In one embodiment, flared mount 26 has two faces 26a, 26b generally facing in opposing hammering directions and are oriented such that a projection of each face 26a, 26b intersects longitudinal axis A ₃ . In one embodiment, faces 26a, 26b each extend away from longitudinal axis A ₃ at an angle a ₂ . In one embodiment, angle a ₂ is approximately 19 degrees. In other embodiments, angle a ₂ is approximately 15 degrees to approximately 25 degrees.

[0048] Flared mount 26 extends, at least partially in some manner, in one or both hammering directions. In one embodiment, flared mount 26 has a generally consistent cross section such that hammer head 14 can be slid horizontally onto flared mount 26 as discussed further below. Faces 26a, 26b of flared mount 26, may in some embodiments, be at least partially non-planar such as convex, concave or stepped. In one embodiment, flared mount 26 has a dovetail, T-shaped, Y- shaped, I-shaped, hook-shaped, bulbous, arrowhead, or cross-shaped cross section as viewed from a horizontal direction.

[0049] Referring to Figs. 6 and 7, in one embodiment, shank 12 is symmetrical about a plane coincident with longitudinal axis A ₃ and shank axis A ₂ . In one embodiment, shank 12 is

symmetrical about a plane coincident with longitudinal axis A ₃ and perpendicular to shank axis A ₂ . In one embodiment, flared mount 26 has a minimum thickness t ₂ in the hammering direction of approximately 1 inch. In one embodiment, thickness t3 of shank 12 proximal to flared mount 26 is approximately 2.5 inches. In one embodiment, flared mount 26 has a total height h ₄ of

approximately 3 inches measured along longitudinal axis A ₃ . In one embodiment, flared mount 26 has a height hi of approximately 1.5 inches where the thickness of flared mount 26 increases in the hammering direction as you move along longitudinal axis A ₃ . In one embodiment, flared mount 26 has a width wi of approximately 6.75 inches measured in the horizontal direction. In one embodiment, the remainder of shank 12 has a width w ₂ of approximately 2.44 inches measured in the horizontal direction. In one embodiment, proximal portion 26d of flared mount 26 extends a height h ₂ of approximately 1.5 inches in the longitudinal direction.

[0050] Referring to Figs. 8-11, hammer head 14 may be releaseably mounted to flared mount 26. Hammer head 14 includes a horizontally extending flared slot 28 configured and dimensioned to engage flared mount 26. Flared slot 28 has substantially the inverse shape of flared mount 26.

Flared slot 28 may act as a mortise to receive flared mount 26. Hammer head 14 includes a body 50 disposed about a horizontally extending flared slot 28 that is defined by a flared inner surfaces 28a, 28b, 28c of body 50. Flared slot 28 may be shaped and dimensioned to substantially match the shape of flared mount 26 (see Fig. 5). Flared slot 28 may be configured and dimensioned to permit body 50 to slide over flared mount 26 in the horizontal direction. Flared slot 26 may be open through first and second lateral sides of hammer head 14 to permit flared mount 12 to slide through flared slot 28 in either horizontal direction. Hammer head 14 may be configured to be coupled to shank 12 in two different orientations such that hammer head 14 may be coupled to shank 12 in a first orientation, decoupled from shank 12, flipped 180 degrees about longitudinal axis A ₃ and recoupled to shank 12 in a second orientation. In one embodiment, hammer head 14 is symmetrical about a plane coincident with longitudinal axis A ₃ and shank axis A ₂ when hammer head 14 is mounted to shank 12. In one embodiment, hammer head 14 is symmetrical about a plane coincident with longitudinal axis A ₃ and perpendicular to shank axis A ₂ . Having a symmetrical hammer head 14 may allow for rotor 22 to be operated in either hammering direction. Having a hammer head 14 that is mountable to shank 12 in either hammering direction may allow for 1) easier installation (e.g., the user does not have to determine which direction the hammering surfaces 14a, 14b need to face relative to shank 12) and/or 2) periodic rotation of hammer head 14 relative to shank 12 if there is uneven wear of hammering surfaces 14a, 14b of hammer head 14.

[0051] The outer shape of hammer head 14 may be selected depending on the application.

Referring to the embodiment shown in Figs. 8-11, hammer head 14 has generally planar hammering surfaces 14a, 14b. A top surface 14c of hammer head 14 may be generally planar. Hammering surfaces 14a, 14b may have a center apex 30a generally aligned with longitudinal axis A ₃ such that hammering surface 14a, 14b each section on either side of center apex 30a slope slightly from center apex 30a and partially face opposing horizontal directions. Top surface 14c may have a center apex 30b generally perpendicular to longitudinal axis A ₃ and shank axis A ₂ such that top surface 14c slopes slightly from center apex 30b and each section on either side of center apex 30b partially face opposing horizontal directions. In other embodiments, one or more of surfaces 14a, 14b, 14c are completely planar, convex, concave, stepped and/or roughened.

[0052] An outer boundary of hammer head 14 may be generally an isosceles trapezoid in a first cross section facing the horizontal direction and generally a rectangle in each of the two cross sections orthogonal to the first cross section. Hammer head 14 may include substantially planar hammering surfaces 14a, 14b that are each generally parallel to a substantially planar surface 26a, 26b (see Fig. 5) of flared mount 26 when hammer head 14 is mounted to flared mount 26. Hammer head 14 may include a first pair of faces 28a, 14a being generally parallel to each other and defining a head thickness t ₇ that is generally uniform in the longitudinal direction (See Fig. 11). Face 28a may extend away from longitudinal axis A ₃ an angle i in the distal longitudinal direction. In one embodiment, angle i of flared slot 28 is approximately 19 degrees. In one embodiment, angle a ₂ is approximately 15 degrees to approximately 25 degrees. Angle i of flared slot 28 is generally equal to angle a ₂ of the flared mount 26. In on embodiment, hammering faces 26a, 26b proximate bottom surface 14d, generally meet an outer surface of shank 12 such that thickness ts of hammer head 14 (see Fig. 11) is generally equal to thickness t ₃ of shank 12 (see Fig. 6) in the hammering direction.

[0053] Referring to Fig. 11, in one embodiment, hammer head 14 extends a height h ₆ in the longitudinal direction of approximately 4.88 inches. In one embodiment, flared slot 28 has a height hio in the longitudinal direction of approximately 3.13 inches. In one embodiment, height hio of flared slot 28 is generally equal to height h ₄ (see Fig. 7) of flared mount 26. In one embodiment, hammer head 14 has a width w ₃ of approximately 6.75 inches measured in the horizontal direction (see Fig. 10). In one embodiment, width w ₃ of hammer head 14 is generally equal to width wi of flared mount 26 (see Figs. 7 and 10). In one embodiment, hammer head 14 has a proximal end thickness ts in the hammering direction of approximately 2.63 inches. In one embodiment, hammer head 14 has a proximal end thickness t ₆ on each side of flared slot 28 in the hammering direction of approximately 0.78 inches. In one embodiment, hammer head 14 extends distally above flared slot 28 along longitudinal axis A ₃ a height hs in the longitudinal direction of approximately 1.75 inches. In one embodiment, flared slot 28 has a minimum thickness t ₇ in the hammering direction of approximately 0.97 inches. In one embodiment, flared slot 28 has a minimum thickness t ₇ in the hammering direction that is equal to or less than the maximum thickness ti (see Fig. 6) of flared mount 26 in the hammering direction and greater than the minimum thickness t ₂ of flared mount 26 in the hammering direction.

[0054] Referring to Figs. 7, 8 and 11, in one embodiment, flared slot 28, along a minimum thickness t ₇ section, has a height hg in the longitudinal direction of approximately 1.25 inches. In one embodiment height hg is generally equal to height h ₂ of proximal section 26d. In one embodiment, flared slot 28, along faces 28a, 28b, has a height h ₇ in the longitudinal direction of approximately 1.13 inches. In one embodiment, height h ₇ of flared slot 28 is generally equal to height hi of flared mount 26.

[0055] Referring to Figs. 2-4, hammer head 14 and shank 12 may be configured such that the coupling between hammer head 14 and shank 12 tightens as hammer head 14 moves distally relative to shank 12 in the longitudinal direction. In one embodiment, flared slot 28 includes a space 48 between top surface 26c of flared mount 26 and top surface 28c of flared slot 28 at least when hammer head 14 is in use. In one embodiment, space 48 has a height hg (see Fig. 8) in the longitudinal direction during use of at least approximately 0.56 inches. Space 48 may allow for flared mount 26 to extend further distally into flared slot 28 during assembly and allow sufficient space for flared mount 26 to slide horizontally into flared slot 28. In one embodiment, height h ₈ of space 48 increases during use. In other embodiments, space 48 is omitted.

[0056] Longitudinal slot 28 may be configured and dimensioned to permit restricted movement of hammer head 14 relative to shank 12 in the distal longitudinal direction when hammer 10 is in use. The amount that hammer head 14 moves relative to shank 12 in the distal longitudinal direction may be predetermined. In one embodiment, the amount that hammer head 14 moves relative to shank 12 in the distal longitudinal direction between coupling and operation of the crusher 100 is approximately 0.06 inches. The amount that hammer head 14 moves relative to shank 12 in the distal longitudinal direction may be minimized to reduce the amount the overall length of hammer 10 changes from a stationary position to an in use position.

[0057] Because of the weight of the hammer head 14, the hammer head 14 may move relative to shank 12 in the proximal direction when the hammer 10 is not and use and therefore loosen the coupling between hammer head 14 and shank 12. Hammer 10 may be configured to prevent hammer head 14 from unintentionally disengaging from shank 12 in the horizontal direction between uses. In one embodiment, hammer 10 includes one or more fasteners or pins 32, 34 that restrict movement of hammer head 14 relative to shank 12 in the horizontal direction. Shank 12 may include one or more holes 36, 38 (see Figs. 5 and 7) that receive pins 32, 34. In one embodiment, pins 32, 34 extend completely through shank 12. Holes 36, 38 may extend through proximal portion 26d of flared mount 26. In other embodiments, pins 32, 34 are screws, projections or tabs. In one embodiment, pins 32, 34 are coupled to secure hammer head 14 to shank 12 in the horizontal direction and removed from shank 12 to decouple hammer head 14 from shank 12. In one embodiment, one or more of the pins 32, 34 extend through shank 12 and extend from two opposing sides of shank 12 in the hammering direction. In other embodiments, pins 32, 34 remain coupled to shank 12 when hammer head 14 is decoupled from shank 12. For example, pins 32, 34 may be spring detents biased to shank 12 such that in order to release pins 32, 34, pins 32, 34 are depressed into the shank 12 until the end or ends are generally flush with shank 12 releasing hammer head 14.

[0058] Hammer head 14 and shank 12 may be configured such that hammer head 14 does not exert a load in the longitudinal direction on the one or more pins 32, 34 in operation as hammer head 14 moves distally in the longitudinal direction relative to shank 12. Referring to the embodiment shown in Figs. 8-11, hammer head 14 may include at least one proximal edge 14d, 14e that include one or more distally extending cutouts 40, 42, 44, 46 configured to receive one or more pins 32, 34 extending from or through shank 12 when hammer head 14 is mounted to shank 12. Removable pins 32, 34 may be positioned at least partially within the one or more distally extending cutouts 40, 42, 44, 46 when pins 32, 34 are engaged with shank 12. In one embodiment, hammer head 14 includes four cutouts 40, 42, 44, 46 each configured to partially extend around one of two pins 32, 34. The one or more pins 32, 34 may be configured and dimensioned to prevent the hammer head from releasing horizontally from the shank when hammer head 14 is mounted to flared mount 26 of shank 12.

[0059] Because the shape and configuration of flared mount 26 and flared slot 28 prevent hammer head 14 from detaching from shank 12 in the distal longitudinal direction, pins 32, 34 may be primarily used to retain hammer head 14 relative to shank in the horizontal direction. However, pins 32, 34 may help to prevent hammer head 14 from moving proximally in the longitudinal direction after hammer head 14 is mounted onto shank 12. In one embodiment, pins 32, 34 are proximal to proximal edges 14d, 14e of hammer head 14 when hammer head 14 is mounted to shank 12. In one embodiment, cutouts 40, 42, 44, 46 are open in the proximal longitudinal direction. In other embodiments, cutouts 40, 42, 44, 46 are closed but dimensioned such that hammer head 14 does not exert a load on the pins 32, 34 in the longitudinal direction during use. In one embodiment, cutouts 40, 42, 44, 46 are elongated slots.

[0060] During an exemplary method of use of hammer 10 and/or hammermill 100, a user grasps hammer head 14 and aligns flared slot 28 with flared mount 26 of shank 12. The user then inserts flared slot 28 over flared mount 26 in the horizontal direction and horizontally slides hammer head 14 relative to shank 12 until cutouts 40, 42, 44, 46 are generally aligned with holes 36 and 38 of shank 12. The user then inserts pins 32, 34 into holes 36 and 38. The user then couples shank 12 to rotor 22. Alternatively, shank 12 may already be coupled with rotor 22 before mounting hammer head 14 to shank 12. Once the hammer head 14 is operably coupled with shank 12, hammermill 100 can be operated, spinning rotor 12 about rotor axis Ai. Rotating rotor 12 about rotor axis Ai generates a centrifugal force that pulls hammer head 14 longitudinally (radially from rotor 22) relative to shank 12.

[0061] The mating shape between hammer head 14 and shank 12 prevents hammer head 14 from decoupling from shank 12 in the longitudinal direction during use. In some embodiments, hammer head 14 moves a distance relative to shank 12 in the longitudinal direction until the mating features between hammer head 14 and shank 12 prevent further longitudinal movement of hammer head 14 relative to shank 12. In other embodiments, the coupling between hammer head 14 and shank 12 is sufficiently tight such that hammer head 14 does not move relative to shank 12 in the longitudinal direction during use.

[0062] A factional force between hammer head 14 and shank 12 may lock hammer head 14 to shank 12 in the longitudinal direction during and after use. In one embodiment, the weight of hammer head 14 causes hammer head 14 to move proximally in the longitudinal direction relative to shank 12 after use to release the frictional force between hammer head 14 and shank 12.

Additionally or alternatively, the user may apply a force in the proximal longitudinal direction to hammer head 14 to release the frictional force between hammer head 14 and shank 12. The user may strike hammer head 14 with a hand held tool such as a hammer in the proximal longitudinal direction to release the frictional force between hammer head 14 and shank 12. In order to remove hammer head 14 from shank 12, the user removes pins 32, 34 from hammer 10 and then slides hammer head 14 horizontally relative to shank 12 until flared shot 28 is slid off of flared mount 26. The frictional force between hammer head 14 and shank 12 may be released before removing pins 32, 34. In one embodiment, the frictional force between hammer head 14 and shank 12 is released after removing pins 32, 34.

[0063] After decoupling hammer head 14 from shank 12, hammer head 14 may be flipped 180 degrees about an axis parallel to longitudinal axis A ₃ and hammer head 14 is recoupled to shank 12. In other embodiments, hammer head 14 is discarded or remounted to a different a shank 12, or repaired and a different hammer head 14 is mounted to shank 12.

[0064] It will be appreciated by those skilled in the art that changes could be made to the exemplary embodiments shown and described above without departing from the broad inventive concepts thereof. It is understood, therefore, that this invention is not limited to the exemplary embodiments shown and described, but it is intended to cover modifications within the spirit and scope of the present invention as defined by the claims. For example, specific features of the exemplary embodiments may or may not be part of the claimed invention and various features of the disclosed embodiments may be combined. Unless specifically set forth herein, the terms "a", "an" and "the" are not limited to one element but instead should be read as meaning "at least one".

[0065] To the extent that the method does not rely on the particular order of steps set forth herein, the particular order of the steps should not be construed as limitation on the claims. The claims directed to the method of the present invention should not be limited to the performance of their steps in the order written, and one skilled in the art can readily appreciate that the steps may be varied and still remain within the spirit and scope of the present invention.