Hammer for a horizontal shaft impact crusher

A hammer mountable at a rotor of a horizontal shaft impact crusher (HSi-crusher), the hammer including a front face, a rear face and at least one recess projecting inwardly into a main body of the hammer from the front face. The at least one recess being arranged to receive an attachment element to mount the hammer at a hammer lifting device.

FIELD OF INVENTION

The present invention relates to a rotor hammer and a method of manufacturing the same, and in particular although not exclusively, to a hammer having a recess extending into its main body from a front face for mounting to a hammer lifting device.

BACKGROUND ART

Horizontal shaft impact crushers (HSi-crushers) are utilized in many applications for crushing hard material, such as pieces of rock, ore etc. A HSi-crusher comprises a crushing chamber housing an impeller (alternatively termed a rotor) that is driven to rotate about a horizontal axis. Pieces of rock are fed towards the impeller and are struck by impeller mounted hammer elements. The rock pieces are disintegrated initially by striking contact with the hammer elements and are then accelerated and thrown against breaker plates (typically referred to as curtains) to provide further disintegration. The action of the impeller causes the material fed to the horizontal shaft impact crusher to move freely in the chamber and to be crushed upon impact against the hammer elements, against the curtains, and against other pieces of material moving around at high speed within the chamber. Example HSi-crushers are described in WO 2010/071550; WO 2011/129744; WO 2011/129742; WO 2013/189691 and WO 2013/189687.

Conventionally, the hammer wear parts are interchanged at the impeller via lifting engagers that are brought into position horizontally at the sides of each hammer. Such an arrangement is often problematic as access to the sides of the elongate hammers is restricted. Additionally, due to the appreciable size and weight of the hammer elements interchange at the impeller carries significant health and safety risks as it is typically required to manually manipulate the hammers into or from their impeller mounted position. Accordingly it is not uncommon for operator fingers to become trapped during installation and removal. What is required therefore is a hammer part that may be conveniently mounted at a lifting tool that addresses the above problems.

SUMMARY OF THE INVENTION

It is an objective of the present invention to facilitate mounting and dismounting crusher hammer elements at an impeller of a HSi-crusher. It is a further specific objective to provide a hammer mountable at a rotor of a HSi-crusher that is capable of being mounted and suspended from a lifting device and/or auxiliary lifting tool such as a crane and the like to enable the hammer to be manipulated and in particular rotated at a suitable lifting device during mounting and dismounting procedures. It is a further objective to reduce and eliminate, as far as possible, the health and safety risks to which operating personnel are exposed during hammer mounting and dismounting procedures so as to avoid specifically injuries to an operator's hands and fingers. It is yet a further objective to enable hammer parts to be raised and lowered substantially vertically at a HSi-crusher to avoid or minimise a need for access to the lateral sides of the crusher during such procedures.

The objectives are achieved via a hammer that is configured specifically for mounting at a lifting device via contact with a front face of the hammer. Advantageously, the hammer comprises at least one bore to receive an attachment, optionally in the form of threaded bolt, to couple the hammer releasably to the lifting device. Suspending the hammer at the lifting device via its front face is beneficial to greatly facilitate mounting and dismounting the hammer at the rotor where access and available space is typically restricted. Additionally, the present hammer is capable of being supported from a position vertically above by the lifting device as the locking wedges are moved into either engaging or disengaging contact with the hammer at the rotor. This is achieved specifically by attachment to the lifting device via the hammer front face. Once the hammer is secured via the locking wedges, the lifting device may be conveniently disengaged from the hammer. Accordingly, the present hammer configuration avoids the need for personnel to physically hold the hammer in position as the locking wedges are either engaged or disengaged. The risk of trapping an operator's hands or fingers is therefore greatly reduced or eliminated.

Advantageously, the present hammer is conveniently and reliably attachable to a lifting device such that the hammer part, once attached, may be held and rotated in a suspended ‘floating’ position such that an operator may manipulate conveniently the hammer part and rotated it about an axis aligned transverse or perpendicular to the vertical (upward and downward) lifting direction by which the hammer part is introduced to or removed from the crusher rotor.

According to a first aspect of the present invention there is provided a hammer mountable at a rotor of a horizontal shaft impact crusher, the hammer comprising: a main body having a length defined and terminated by length ends and a width defined and terminated by lengthwise extending sides; a front face of the main body intended to be forward facing with a rotational direction of the rotor and a rear face of the main body intended to be rearward facing opposed to the rotational direction of the rotor; a lengthwise extending edge of each of the lengthwise extending sides defining a part of a perimeter of the front face and representing a leading edge to contact and break material fed into the crusher; characterised by: at least one recess extending into the main body from the front face to receive an attachment element to mount the hammer at a hammer lifting device.

Reference within this specification to the main body ‘front face’ encompasses the exposed surface at the front face side of the main body and includes specifically an exposed surface of one or more mount projections extending outwardly from a front face side of the main body.

The present hammer may comprise one or a plurality of recesses extending into the main body from the front face. The recesses may comprise a variety of different depths and shape configurations and in particular cross sectional profiles. Optionally, the cross sectional profile shape of the recess (in a plane of the main body) is circular such that the recess comprises a generally cylindrical cavity shape profile. The recess may also optionally comprise one or more angled sections to allow an attachment device or elements to be inserted into the recess and moved laterally (in the widthwise and/or lengthwise directions of the hammer) to provide locking engagement. The recess may therefore comprise a channel, part-channel or groove like configuration for releasable mating with a corresponding lug or other attachment element such as a bayonet, pin, rod, screw or the like.

Preferably, the at least one recess comprises threads to receive and cooperate with a threaded shaft of an attachment bolt. Preferably, the threads extend over the full depth of the recess being formed on the inward facing surface that defines the wall of the recess being generally cylindrical. Such an arrangement is advantageous to cooperate with a conventional threaded shaft of, for example, an attachment bolt.

Preferably, the front face is generally concave and the rear face is generally convex. Such an arrangement optimises the crushing characteristics of the hammer during use.

Optionally, the hammer further comprises a mount projection extending outwardly from a front face side of the main body, the at least one recess extending into the mount projection. Optionally, the mount projection is substantially rectangular and extends lengthwise between the length ends of the main body. The mount projection facilitates mounting and dismounting of the hammer at a lifting device by providing a raised plateau region having a substantially planar contact face that may be mated in close touching contact with a corresponding flat or planar mount face of a lifting device attachment bracket.

Optionally, a depth of the at least one recess is substantially equal to a thickness by which the mount projection extends outwardly from the main body. Such an arrangement is beneficial so as to not affect or weaken the main body. Optionally, a depth of the projection is less than a corresponding thickness of the main body (between the front and rear face to one lateral side of the projection). Optionally, the projection comprises a depth in a range 5 to 30%, 5 to 25% and more preferably 10 to 20% of a thickness of the main body being defined by a distance between the front and rear face of the main body at each length end.

Preferably, the hammer further comprises at least one insert embedded to extend inwardly from the front face of the main body, the insert comprising the at least one recess. Preferably, the insert is formed integrally with the main body as the main body is cast formed. The present hammer is preferably formed from a casting process in which a flowable metal is introduced into a mould and allowed to solidify. The inserts may be conveniently supported within the mould during introduction and settling of the flowable metal so as to be locked and formed integrally within the cast main body. Advantageously only an end surface of the insert is exposed in the resulting as-formed cast hammer such that the inserts are effectively fused to the main body and extend inwardly into the main body (or projection) from the front face. Optionally, the insert comprises a flange that extends radially outward from a main body of the insert. The flange may comprise one or a plurality of arms (e.g., two) extending from the insert main stem. This flange is advantageous to ensure that the insert is held firmly by the metal which solidifies around it such that when pressure is applied in use (i.e., via the tightening of attachment bolts) the insert cannot move axially or radially within the casting.

Preferably, the hammer comprises a plurality of recesses extending inwardly from the front face. In particular, the hammer comprises at least two recesses and in particular two threaded bores projecting inwardly into the main body (encompassing a main body projection) from the front face. Preferably, the hammer comprises a pair of recesses spaced apart in a lengthwise direction between the length ends and extending into the main body from the front face.

According to a second aspect of the present invention there is provided a method of casting a hammer mountable at a rotor of a horizontal shaft impact crusher, the method comprising: mounting an insert within a mould so that one face of the insert is exposed to be outward facing from the mould; filling the mould with a flowable metal such that the face of the insert is exposed from the metal; allowing the metal to solidify within the mould to set the insert within the mould and to define a main body; the main body comprising a length terminated by length ends and a width defined and terminated by lengthwise extending sides, the main body also having a front face intended to be forward facing with a rotational direction of the rotor and rear face intended to be rearward facing opposed to the rotational direction of the rotor, a lengthwise extending edge of each of the lengthwise extending sides defining a part of a perimeter of the front face and representing a leading edge to contact and break material fed into the crusher; wherein the insert comprises a recess extending inwardly from the front face.

Preferably, the hammer is formed by a sand mould casting process in which a sand, and optionally a suitable bonding agent (such as clay) is mixed or is present within the sand, to form the mould and into which the flowable metal may be poured. As will be appreciated, the sand may be typically contained within a framework or suitable flask enclosure.

Optionally, the method further comprises mounting a plurality of inserts within the mould to provide a plurality of recesses extending inwardly from the front face. Optionally, each of the inserts may comprise threads to receive and cooperate with a threaded shaft of an attachment bolt. Optionally, the main body (encompassing a mount projection) is formed from a Chrome based metal and the insert is formed from the same or a different material to the main body.

Optionally, the threads are formed at the insert prior to the step of mounting the insert within the mould. Alternatively, the threads may be formed at the insert after the step of allowing the metal to solidify within the mould.

According to a further aspect of the present invention there is provided an assembly attachable to an auxiliary lifting tool, the assembly comprising a hammer mountable at a rotor of a HSi-crusher and a lifting device suitable to be raised and lowered into the chamber of the crusher and to raise and lower the hammer relative to the rotor.

Referring toFIG. 1a horizontal shaft impact crusher1(HSi-crusher) comprises a housing2in which an impeller indicated generally by reference4is rotatably mounted. A motor, (not illustrated) is operative for rotating a horizontal shaft6on which the impeller4is mounted. As an alternative to impeller4being fixed to shaft6, impeller4may rotate around shaft6. In either case, impeller4is operative for rotating around a horizontal axis, coaxial with the centre of shaft6.

Material to be crushed is fed to a feed chute8, which is mounted to an inlet flange9of housing2, and enters a crushing chamber10positioned inside the housing2and at least partly enclosing impeller4. Material crushed within the crusher1exits the crushing chamber10via a crushed material outlet12. Housing2is provided with a plurality of interior wear protection plates14operative for protecting the interior of crushing chamber10from abrasion and impact by the material to be crushed.

Crusher1comprises a first curtain16, and a second curtain18arranged inside crushing chamber10. Each curtain16,18comprises at least one wear plate20against which material may be crushed. A first end22of first curtain16is mounted via a horizontal first pivot shaft24extending through an opening26formed in curtain16at the first end22. First pivot shaft24extends further through openings in the housing2to suspend the first end22in the housing2. A second end28of first curtain16is connected to a first adjustment device30comprising at least one adjustment bar32. A first end34of second curtain18is mounted by means of a horizontal second pivot shaft36extending through an opening38formed in curtain18at first end34. Second pivot shaft36extends further through openings in the housing2to suspend the first end34in the housing2. A second end40of second curtain18is similarly connected to a second adjustment device42comprising at least one adjustment bar44.

Impeller4is provided with four hammer elements46according to the specific embodiment, with each element46having a generally curved or ‘banana’-like shape profile, when view in cross-section. An arrow R indicates the rotational direction of impeller4. A leading edge48of each respective hammer element46extends in the direction of rotation R. Prior to extended use, hammer element46is symmetric around a central portion50. However, once leading edge48has been worn element46can be turned and mounted with its second leading edge52operative for crushing material.

The HSi-crusher1can be adjusted to a first crushing setting, which for example may be a primary crushing setting, for crushing large objects (typically having a maximum particle size of 300-1200 mm), and a second (or secondary) crushing setting being different from the first setting for crushing intermediate size objects (having a maximum particle size of less than 400 mm and typically 20-400 mm). When crusher1is operated in the primary setting the crushed material exiting crusher1via the outlet12would typically have an average particle size of 35-300 mm, and typically at least 75% by weight of the crushed material would have a particle size of 20 mm or larger. When crusher1is operated in the secondary setting the crushed material leaving the crusher1via the outlet12would typically have an average particle size of 5 to 100 mm, and typically at least 75% by weight of the crushed material would have a particle size of 5 mm or larger. Within the present specification the ‘average particle size’ refers to weight based average particle size.

Adjusting crusher1to the primary crushing setting would typically involve retracting the first and/or second curtains16,18away from impeller4, to form a crushing chamber10having a large volume and a large distance between the impeller4and the wear plates20of curtains16,18. Such retraction of at least one curtain16,18would be performed by operating the first and/or second adjustment devices30,42, which may typically involve hydraulic cylinders and/or mechanical adjustment devices using threaded bars. Adjusting the crusher1to the secondary crushing setting would, on the other hand, typically involve moving the first and/or second curtains16,18towards the impeller4by means of operating the first and/or second adjustment devices30,42, to create a crushing chamber10having a small volume and a short distance between the impeller4and the wear curtain plates20. In addition to adjusting the position of the curtains16,18, the horizontal shaft impact crusher feed chute8is adjusted to feed the material into the crushing chamber10in a first direction F1when crusher1is adjusted to the primary setting, and in a second direction F2when crusher1is adjusted to the secondary setting. Hence, the first crushing setting is different from the second crushing setting. Furthermore, the first direction F1of feeding material to the crusher1is different from the second direction F2of feeding material to the crusher1.

The adjustment of the HSi-crusher1from a primary crushing setting to a secondary crushing setting may also involve adjusting the positions of an upper feed plate17and a lower feed plate19that are located just inside of the inlet flange9of the housing2of the crusher1. The feed plates17,19protect the inlet of the housing2, and provide the material fed to housing2with a desired direction. InFIG. 1, the upper and lower feed plates17,19are adjusted to the primary setting (shown in unbroken lines) with the intention of directing the coarse material towards impeller4and the first curtain16when the crusher1operates in the primary setting. The positions of the upper and lower feed plates17,19in the secondary setting are indicated with broken lines inFIG. 1. As can be seen the upper and lower feed plates17,19are, in the secondary setting, arranged for directing the material directly towards the impeller4. In this manner, the rather fine material fed when the crusher1operates in the secondary setting will receive more ‘hits’ from the impeller hammer elements46leading to a greater reduction in the size of the material.

In operation material to be crushed is fed to the feed chute8and further into the crushing chamber10, either in the direction F1if the crusher1is adjusted to the primary setting or in the direction F2if crusher1is adjusted to the secondary setting. The material will first reach that part of the crushing chamber10which is located adjacent to first curtain16, being located upstream of the second curtain18as seen with respect to the direction of travel of the material. Impeller4is rotated at typically 400-850 rpm. When the material is impacted by the impeller elements46it will be crushed and accelerated against wear plates20of first curtain16where subsequent and further crushing occurs. The material will bounce back from first curtain16and will be crushed further against material travelling in the opposite direction and then again against the elements46. When the material has been crushed to a sufficiently small size it will move further down the crushing chamber10, and will be accelerated, by means of the elements46, towards wear plates20of the second curtain18, being located downstream of first curtain16. When the material has been crushed to a sufficiently small size it exits chamber10via outlet12as a flow of crushed material FC.

Referring toFIGS. 2 and 3, each hammer element46comprises a generally rectangular main body having a main length defined by and extending between a first end58and a second end59. A pair of ends faces60extend widthwise at ends58,59. The pair of material contact edges48and52extend lengthwise between end faces60. Accordingly, element46comprises a front face53configured for positioning with the rotational direction of impeller4so as to represent a leading face. Element46further comprises a rear face54positioned opposed to the rotational direction of impeller4so as to represent a trailing face of element46. To optimise the crushing performance of element46, front face53is generally concave whilst rear face54is generally convex. Accordingly, leading edge48represents a forwardmost part of face53when element46is mounted at impeller4via locking wedges95. Each respective leading edge48,52is generally curved (or rounded) and defines a leading edge of a pair of lengthwise extending side faces62with an adjacent trailing edge indicated generally by reference61.

A generally rectangular mounting projection94is positioned at a mid-width position of front face53and extends in a lengthwise direction between ends58,59. Projection94terminates at an exposed substantially rectangular contact surface55that is positioned approximately co-planar with each leading edge48,52. A pair of threaded bores extend into projection94with each bore56spaced apart in the lengthwise direction and aligned at the same widthwise position so as to be generally central within contact surface55.

Rear face54also comprises a plurality of raised ridges indicated generally by reference57resultant from the casting of element46involving the use of ‘runners’ and ‘risers’ as will be appreciated by those skilled in the art.

Each recess56is formed within a respective insert102that is cast integrally with the main body of hammer46during a sand casting process. That is, according to a preferred method of manufacture, each insert102is positioned within a suitable sand based mould retained within a flask using appropriate runners and risers. A chrome based flowable metal is then introduced into the mould to surround inserts102and then allowed cool and solidify so as to lock and fuse inserts102within the main body of hammer46. Each insert102comprises a front face103a rear face104. Rear face104is positioned to be downward facing into the mould during casting whilst front face103is aligned approximately coplanar with leading edge58so as to remain exposed once the chrome metal has set. That is, each insert front face103is positioned coplanar with contact face55whilst rear face104is embedded within projection94and/or the hammer main body.

To facilitate manufacture, each insert102is drilled or machined to form each respective recess56prior to each insert102being introduced into the mould prior to casting. However, according to further specific implementations, each bore56may be formed aft casting hammer46with inserts102being integrally formed therein.

A lifting device63, suitable to releasable mount the hammer46, comprises an elongate main body64formed from a generally hollow bar having a first end65and a second end66. Main body64comprises a first side88and a second side89positioned at either side of a longitudinal axis96extending centrally through main body64. A fin67projects laterally from second side89and comprises an eyelet68positioned at an outward end101of fin67. A second fin end69is mounted at main body64via an elongate groove70extending axially through main body64and having a depth sufficient to accommodate fin end69. Fin67is secured rigidly to main body64via welding or suitable attachment pins or bolts (not shown). An axle80is rotatably mounted at an axle mounting87provided at main body second end66. Axle80extends laterally from both sides88,89to provide a mount for a flange77positioned at first side88and an attachment bracket83positioned at main body second side89. Flange77is rigidly mounted to axle80via an axle mount81with coupling provided by a mounting bolt82. Flange77comprises a generally disc-like configuration being generally planar with an oval shape profile. A pair of notches or recesses78,79extend radially inward from a perimeter90of flange77. Notches78,79are positioned diametrically opposite one another at respective ‘twelve o'clock and six o'clock’ positions.

Attachment bracket83also comprises a plate-like body having a generally planar configuration. Bracket83is generally rectangular with a rearward face of bracket83attached rigidly to one end of axle80via an axle mount86so as to present an outward facing mount face100for positioning against hammer contact face55. Accordingly, mount86and bracket83are configured for rotation about an axis97extending centrally through axle80. Flange77, being mounted at one end of axle80, is rotatably locked with hammer attachment bracket83with both components rotatably mounted with respect to main body64about rotational axis97. Accordingly, rotation of flange77about axis97provides a corresponding rotation of bracket83about axis97.

Bracket83comprises a first pair of mount holes85spaced apart in a lengthwise direction at bracket83between respective lengthwise end edges98. A second pair of mount holes91are also spaced apart in the lengthwise direction between bracket end edges98with the first and second pairs of holes85,91spaced apart in the widthwise direction between bracket widthwise end edges99. Holes85are positioned approximately mid-width between widthwise end edge99whilst the second pair of holes91are positioned closer to one of the widthwise end edges99so as to be positioned between the first pair of holes85and one end edge99.

Main body64further comprises an elongate slot71extending a short axial distance through sides88and89. A locking lever72extends through main body64being aligned transverse (including perpendicular) to axis96so as to be aligned generally with axle axis97. Lever72projects through slot71so as to extend laterally outward from both sides88,89. A first lever end75is mounted at main body64via a pivot mount74and a pivot pin76extending through mount74and lever end75. Accordingly, a second lever end73is capable of pivoting about pin76to be moved in the axial direction of main body64within slot71towards and away from flange77. In particular, lever72is mounted axially to one side of flange77such that in a lowered engagement position ofFIG. 4, a part of lever72is configured for positioning to be received within one of the notches79. With lever72positioned accordingly, flange77is rotatably locked at axis97. Accordingly, attachment bracket83is also rotatably locked at main body64. Lever end73may be grasped by a user and raised in a direction of axis96so as to free notch79and allow flange77to be rotated to provide a corresponding rotation of bracket83about axis97.

FIG. 6illustrates lifting device63suspended from a chain92of an auxiliary lifting tool such as a crane (not shown). A lowermost end of chain92comprises an attachment coupling93configured to engage eyelet68and suspend device63from the lifting crane. Hammer element46is demountably attachable to lifting device63via attachment bracket83engaging the contact surface55of mount projection94. In particular, element46is releasably secured to device63via a pair of mounting bolts84provided through one of the pairs of holes85,91that engage into the hammer bores56as hammer element46is mated against bracket mount face100.FIG. 6illustrates the mounting of a non-symmetrical element46via the second pair of holes91that are positioned off-centre (in the widthwise direction) of bracket83. Each bolt84is mated into the respective threaded bore56so as to releasably secure element46to device63.

A length of axle mount86in a direction of axis97is configured such that element46is suspended on an axis extending through chain92(that bisecting eyelet68) such that the elongate tubular main length64is suspended substantially vertically. Element46is held below coupling93and fin67by substantially the full length of main body64so as to allow unhindered rotation of element46about axis97when suspended from the auxiliary lifting tool. That is, with lever72raised to a non-engaging position within slot71, a user may grasp flange77so as to rotate it about axis97providing a corresponding rotation of element46about axis97. Element46may be locked in two different rotational positions corresponding to the engagement of each respective notch78,79by lever72.

So as to ensure the mass centre of element46is generally coaxial with axis97, element46may be mounted at different positions relative to device63via the use of either set of bolt mounting holes85,91.