US2901187A - Methods and apparatus for crushing materials - Google Patents

Description

AU8 25, 1959 H. G. HEYMANN 2,901,187

METHODS AND APPARATUS FOR CRUSHING MATERIALS Filed Feb. 18, 1955 United States Patent Patented Aug. 25, 1959 llce METHODS APPARATUS FOR CRUSHING MATERIALS Hans G. Heymann, Ulm (Danube), to Hein Lehmann & Company, Dusseldorf, Germany Germany, assigner Aktiengesellschaft,

This invention relates to methods and apparatus for crushing materials and more particularly to such methods and apparatus utilizing oscillation technique.

With the development of oscillation technique in the iield of crushing materials, eiforts have been made to substitute oscillation motions for the kinds of motions which occur in known types of crushing machines. This has been done primarily to increase productivity and to reduce wear and tear as well as the required driving force.

Probably the earliest equipment of this kind is the swing mill which operates similarly to the ball mill. In the swing mill, the oscillation acceleration of the mass of the ball, instead of the free fall acceleration, constitutes the crushing force. Also, the number of crushes per unit time is substantially greater in comparison to the ball mill. Therefore, larger output with less power can be achieved in a swing mill as compared to a ball mill provided the respective installations are substantially equal in space and material utilized in their construction. However, these advantages of the swing mill are offset by such disadvantages as excessive deterioration of the crushing surfaces, noisiness, and the presence of free vibration forces at the points of support of the swing mill. These forces have to be absorbed by heavy foundations or other suitable and expensive absorbing means. Consequently, the swing mill has remained limited to small size machines and has therefore not replaced the ball mill.

It has also been proposed to utilize oscillation technique in connection with jaw Crushers. The employment of oscillation technique enables output to be increased with less expenditure of power but, here again, disadvantages exist to otfset the advantages so that jaw crushers of earlier design are still being utilized.

)inasmuch as the force of the mass of the oscillating crusher jaw must be fully utilized as the crushing force, the direction in which this force is exerted is a decisive factor. However, as is well known, a phase diiference of 180 exists between a path traversed by an oscillating point mass and the corresponding acceleration path of said mass so that the signs of these paths are always opposite. When the direction of the dynamic force is normal to the surface of the grain, namely the surface to be hit, so that the periodic force works like a hammer, then it can easily happen that the locking movement of the mouth is stopped unintentionally when the resistance to the crush becomes too great. All dynamic crushers in which both jaws perform opposite oscillations about a pivot point, rigid or loose, suer this possibility. The impacts applied to alleviate such a condition must be comparatively large and therefore require very strong bedding. In addition, the opposite motion of the freely swinging jaws requires a mechanical system of such dimensions and complicated construction as to make such advantages as can be obtained questionable.

From a purely technical point of View, it is substantially more favorable when the direction of the dynamic force coincides with the forward direction. In this case the force produces a torque. In other words, a periodic twisting force and a periodic pressing force, which corresponds to the curvature of the curve along which the pressing force is exerted, are simultaneously applied to the grain. However, from the standpoint of wear and tear, the stationary above lying jaw utilized in known types of apparatus deteriorates during the slipping of the grain (before the grain begins being crushed) until a sullciently great friction lock is produced by both crushing surfaces. This slipping, which repeats itself with each period of oscillation, is equivalent to the wear and tear of the grinding jaw and, naturally, also to the rubbing off of the grain, namely, an undesirable production of dust. Another disadvantage in this particular approach to the problem is the fact that the underlying jaw of the mouth must, apart from the crushing, endure also the pushing forward of the product being crushed. If it is assumed that a grain lying in the middle of the mouth has already been crushed to the desired size, then the crushed pieces can pass the opening of the mouth only when the previous grains have left the mouth. This needless delay in passing a grain which has already been ground to the desired size considerably reduces the passage capacity and increases the dust content.

In recent years, Crushers with a stationary mouth have been replaced by Crushers in which the movable jaw is formed as a cone which moves both in a circular motion and a reeling motion in the radial direction. Thus, a torque is applied to the grain along an axis coinciding with the forward direction which is at the same time a downward direction so that each piece crushed to the desired size can fall freely out of the opening of the mouth. When, however, the reeling curve is drawn as the zero line on the circular path in a plan drawing of the machine, it is then obvious that the essential crushing force is produced by the tangential circumferential force while the direction of the oscillating mass is normal to the opening of the mouth for all points on the circumference. The rigid outer jaw causes wear and tear to occur on the milling surfaces and a premature crushing of the grain while it then rst begins to Aroll olf without slipping when the friction lock is produced. A further disadvantage of the cone crusher is that the driving motor must be mounted very strongly so as to be able to withstand the reeling motion of the movable cone jaw and the repeated accelerations and decelerations produced during the revolutions connected with such motions.

The disadvantages mentioned above in connection with various types of apparatus utilizing oscillation technique are substantially eliminated by following the teaching of the present invention. It is therefore an object of the present invention to provide new and improved methods and apparatus for crushing materials wherein oscillation technique is utilized.

It is another object of the present invention to provide such methods and apparatus whereby either dry or sticky material may be crushed satisfactorily.

It is a further object of the present invention to provide such methods and apparatus whereby materials of a wide range of hardness may be crushed with a minimum expenditure of power and minimum production of dust.

Briefly described, a preferred practice of the present invention comprises suspending a piece of material to be crushed against free fall by supporting it at substantially opposite sides and then applying rapidly occurring periodic twisting squeezes `to the suspended piece of material to fracture it into smaller pieces capable of free fall. The periodic twisting squeezes are preferably alternating force couples applied to the piece of material in a rapid oscillatory manner in horizontal directions. `Such application of forces to the piece of material appears to build up such stresses Within the piece of material that it literally explodes thus fracturing into smaller pieces along any natural cleavage lines 'which may exist in the piece lof material fand hence minimizing dust production. A downwardly directed Vforce '-is preferably also 'applied to .the ipiece of material while the vtwisting squeezes are ap- .plied to it.

-A preferred 'embodiment of apparatus according to the iteaching of the present invention comprises a pair of 'crusher -jaws each having a crushing surface, the-surfaces being disposed Opposite each 'other -to dene a substantially vertical crush slit. The jaws are supported for 'swinging 'movement with 'respect to each other and are driven so vthat Aboth Ajaws loscillate relative Vto each other 'in a horizontal plane, `each along a curved rpath. The .path of movement of eachjaw is thus along -a -curve'and nthe jaws move simultaneously Iin yopposite directions so that -they are yclosest to `each `other at the 'midpoint Vof their travel in their 'respective curves and lcan thuspress 1into the material being crushed as -they 'pass most closely lto each other. Each crusherjaw is preferably supported by a pair of elastic .platedike lsupport 'members which 'support the yjaw for horizontal vswinging movement with respect to a vertical frame member from which the snpport members extend.

'Other objects and advantages of the present `invention will become more apparent from the following detailed 'description taken in conjunction with the attached drawings in which:

Fig. l is an velevation view Vin *section of a preferred embodiment of apparatus according to the teaching of the ypresent invention;

Fig. 2 is a plan view of said Ipreferred embodiment;

Fig'. 3 is a view showing the paths of Amovement of two opposed points on the crushing surfaces of the crusher jaws shown in Figs. `l and 2; and

Fig. 4 is a .partial showing in elevation of a modied form of apparatus according to the teaching-of the present invention.

Referring to Figs. 1 and 2, the material to be crushed is fed from a suitable source, not shown, into a stationary funnel or hopper 1 which is positioned above the crusher jaws 2 and 3 as shown in Figs. 1 and 2. Crusher jaws 2 and 3, which may be referred to as swingable masses, have opposed similarly shaped crushing Vsurfaces 2a and 3a respectively which converge from top to `bottom as shown in Figs. l and 2 to forma funnel shaped passage 4 having a discharge opening or mouth 5. The width ofthe discharge lopening corresponds to the desired fineness of crushed material. It is to be noted, furthermore, that the opposed crushing surfaces 2a and 3a dene a substantially vertical crushing slit extending from the region 5a of funnel l to the discharge 'mouth 5 of lthe funnel. Moreover, each crusher jaw 2 and 3 is elongated in 'a horizontal direction as shown in Fig. 2 and it is to be noted that the crushing surfaces 2a and 3a may be said to have a convex curvature in `a vertical direction. 'Crushed material discharged from mouth 5 is carried away by a suitable `means such as a 'conveyor 6.

Each crushing jaw 2 and 3 is supported by a pair 'of supporting guide members 7 which are connected to each jaw ladjacent 'the ends of the ja'w as shown in Fig. 2 and extend between each jaw Vand an 'upstanding substantially vertical frame member A8. Any suitable means may be used to connect member 7 to a jaw and one of the frame members 8 respectively. As shown in Figs. 'l and 2, supporting guide members 7 -are thin plate-like members having sufficient strength `to support the crushing jaws but nevertheless being bendable in a horizontal direction. The 'resilience or, to put it another way, the rigidity of 'members 7 may be varied depending upon the type of l'material 'to `be crushed. ySteel is a suitable material yfor members 7. I

The upstanding framemembers 8 rest upon a foundation or base member 9. It s apparent from viewing V4 Figs. l and 2 that the crushing jaws are supported so as to be positioned substantially midway between frame members 8 and above foundation member 9. Furthermore, each crushing jaw is substantially parallel to the frame member from which it is supported whereby the crushing jaw may swing in a horizontal direction back and forth with respect to its supporting frame member.

In the 'embodiment `of apparatus according A'to the Eteaching of the present invention 'shown in Figs. 1 and 2, the crusher jaws are Aactuated by connecting -rods 10 and 11 which are connected toja'ws 2 and 3, respectively, by suitable means such as links 12. Links 12 "may'be'of any suitable construction and, for example, may be a type of link such as is used in vautomotive vehicles vwherein the link comprises a vulcanized 'rubber part positioned between metal parts, the connecting rod being connected to the rubber part in order to provide a more silent operation. The lopposite ends of connecting rods 10 and 11 are-connected 'to eccentric socket members -14 and '15. Socket members 14`and 15 may be 'of any suitable construction l'whereby 'they can be adjusted or otherwise changed so that ythe length of stroke of connecting vrods 10 and 1'1, and thus the amplitude 'of motionof 'these rods, may lbe predetermined as desired. Socket members 14 and 15 'are fastened to agitator shaft 13 so `as to move therewith. Shaft 13, in lturn, is journaled -for rotation in shaft support members 1'6. yFlywheels 17 are mounted on shaft 13 as shown in Fig. 2 to provide more uniform rotation of the shaft. Shaft 13 4may be driven in any suitable `manner as by a driving lmotor 19 acting through a suitable'coupling 18.

Referring now `to Fig. 3, A and 'B represent two corresponding points on crushing surfaces 2a and 3a. These points may be located at an arbitrary height in funnel 4, such as a 'height in region 5a for example, and it is assumed that points Aand B are being viewed from above, i.e. looking down into the 'mouth -of funnel 4. The width of the funnel, namely, 'the distance between points A and B at the assumed yheight level, with the crushing surfaces being substantially exactly opposite eachother as shown in Fig. 2, is identiedas x. When the-apparatus is being operated so thatjaws 2 and 3 -are in motion then, during one full oscillation, point A moves in van approximately circular path K from A to C (turning point), from C back past A to D (turning point) and finally back to A. In contrast, the path of the corresponding point B 'of the other crushing jaw within the same period of time is from B to E, :then from E 'back past YB to F, and then from F back to B.

The cho'rd L of path CD or path 'EF corresponds in length to the'doubled'eccentricity of the eccentric sockets 14 and 15 and 4establishes the amplitude of the oscillation. In other words, 'the vamplitude is established by the sum 'o f the distances lof movement of connecting rods 10 and l11 from the equilibrium position in Fig. 2. IFor 'this amplitude L the 'width gof lthe funnel, at the arbitrary height selected, 'increased to the distance y. In other words, points A and B are separated the distance y when point A is at C and point B at E or when point A is at D and B -at F.

If it yis assumed that a piece of material to be crushed has a diameter 'y and is ilocated Iat. the assumed height vin funnel '4 then,- during movement 'of the crushing surfaces Za and 3a toward eachother, until they are only the distance fx from each other, Ethe .piece of material is crushed to `r'iieces having a 'diameter no greater than x. As the crushing surfaces recede from each other, such as going from Ato D and B to F respectively, the pieces of material which have been crushed to a diameter x can fall freely under the force or pressure exerted by the pieces of material in the 'upper part of funnel 4 which bear down on the pieces being crushed. The piece 'of material thus crushed may fall to a lower height level in funnel '4, if the -piece has not Ialready been crushed to rh@ 'desired nerress, the width y at the row'er height revel r.- Th1.

corresponding to the Width x at the upper height level. The crushing is again repeated, if necessary, until the piece is crushed still ner and can drop yto a still lower height level in the funnel. However, each piece of material which has already been crushed to the desired neness can fall outv of the funnel, passing through discharge mouth 5 unhindered, so that no dust is produced by excess rubbing.

Fig. 3 shows that according to the teaching of the present invention an unintended locking, which can stop the oscillatory movement of the jaws, is elfectively avoided. This is because the maximum forces of the swinging masses (crusher jaws 2 and 3)V come to full force as a couple at the turning points C and E as Well as D and F and because, also, at the same time, crushing surfaces 2a and 3a do not press arbitrarily deep into the material being crushed but only to the extent of the path curvature, i.e. Ithe curvature of paths CD and EF. It is further apparent Vthat the depth of curvature, the distance 1/2 (y-x), which is determined in part by the length and elasticity of supporting members 7, can be predetermined in advance so that the periodic pressing force at the moment the piece of material being crushed is twisted can be predetermined in advance in accordance with the breaking quali-ties of the material being crushed.

lt is thus seen that each piece of material being crushed, or milled or ground as it may be described, is suspended against free fall by being supported at substantially opposite sides of the piece of material and is then subjected to rapidly occurring periodic twisting squeezes until it is fractured into smaller pieces of material. The twisting squeezes, or periodic force couples, applied to each piece of material appear to build up such internal strains in the piece of material, due to the rapid oscillatory nature of the imparted forces, that the piece of material literally explodes from within and fractures along any natural lines of cleavage present in the piece of material. Dust production is thus effectively minimized.

Referring to Fig. 4, it will be noted that one of the supporting guides 7 is shown as being attached to crusher jaw 2 adjacent one end of the jaw but that the supporting guide is inclined with respect to the vertical. The corresponding supporting guide 7 which is connected to crusher jaw 3 (not shown) is shown in dotted outline as being positioned vertically. Dot-dash lines 10a and 11a represent the paths of application of force by connecting rods 10 and 11 when these connecting rods are in the equilibrium position such as is shown in Fig. 2. The point O indicates the push-through point of shaft 13, this again being the condition shown in Fig. 2 for the embodiment illustrated there. With crusher jaw 2 being supported by members 7 which are inclined with respect to the vertical, it being understood that both members 7 connected to jaw 2 are inclined while both members 7 connected to jaw 3 are vertical, it is apparent that when crusher jaw 2 swings downwardly it will drag along a quantity of material which is in process of being crushed. Theoretically, the quantity dragged along corresponds to the vertical projection of one-half of the amplitude of the swinging crusher jaw 2.

The weight of the material located in funnel 4 which lies above the quantity of material in process of being crushed exerts a static downward pressure on the quantity of material which is in process of being crushed. The greater that this static pressure is, the more uniform and steadier is the downward motion of the swinging crusher jaw 2 and also the quantity of material which is in process of being crushed. Then, when crusher jaw 2 swings back upwardly it is hindered by the aforementioned static pressure so that the material being crushed is again dragged upwardly. In other words, having one of the crusher jaws, such as crusher jaw 2, swinging in a path located in a plane inclined to the horizontal, while the other crusher jaw swings in a plane which is substantially horizontal, increases the passing speed of the material being crushed. As indicated in Fig. 4, crusher jaw Z oscillates along a path located in a plane inclined to the horizontal as indicated by dot-dash line 10a whereas crusher jaw 3 oscillates in a path located in a substantially horizontal plane as indicated by dot-dash line 11a. The embodiment of the apparatus shown partially in Fig. 4, and just described, has particular utility for crushing sticky or viscous materials.

It is thus seen that according to the teaching of the present invention a piece of material to be crushed is suspended against free fall by being supported at substantially opposite sides of the piece of material and, while So supported, is subjected to rapidly occurring periodic twisting squeezes, or force couples, which fracture rthe piece of material into smaller pieces of material capable of free fall. If the fractured piece is caught at a lower level in the apparatus, it is again subjected to rapidly occurring periodic twisting squeezes whereupon it is again fractured and can -fall freely again. Thus the fraoturing of a p-iece into smaller pieces can occur successively at different levels until finally the pieces of material are of the desired fineness and may fall freely from the disch-arge mouth of the funnel. Of course, if the piece of material is fractured to the desired iineness in the rst instance then it may fall freely without further crushing.

By suitably choosing the proper materials and the desired length for supporting guides 7, the periodic pressing force exerted on the piece of material to be crushed can be predetermined in advance so as to meet the requirements for crushing a particular material. Also, the amplitude of oscillation of the respective crushing jaws can be predetermined to achieve optimum clnshing action for the driving force supplied to swing the crushing jaws. lt is found that, by following the teaching of the present invention, very hard materials can be crushed effectively without excessive power requirements. For example, such a hard material as Taconite may be crushed effectively. It is also found that the crushing surfaces 2a and 3a do not have to be as hard as the material being crushed since each force applied to the material being crushed is applied along a curved path and is thus applied tangentially to the material rather than being a `direct impact force such as a hammer type of blow.

While I have described and illustrated embodiments of my invention, I wish it to be understood that I do not intend to be restricted solely thereto but that I do intend to cover all modifications thereof which would be apparent to one skilled in the art and which come within the spirit and scope of my invention.

What I claim as my invention is:

l. The method of crushing a piece of material which comprises the steps of suspending said piece of material against free fall by supporting said piece of material at substantially opposite sides of said piece of material, applying rapidly occurring force couples to said piece of material by moving both supports simultaneously to fracture said piece of material into smaller pieces of material capable of ifree fall, said force couples being applied in a direction substantially perpendicular to the path of free fall, and applying a downwardly directed force to said piece of material while said force couples are being applilelzd to said piece of material to assist in causing free 2. The method of crushing a piece of material which comprises the steps of suspending said piece of material against free fall by supporting said piece of material at substantially opposite sides of said piece of material, and then applying rapidly occurring crushing forcesto said piece of material by moving both supports simultaneously, one crushing force being applied to said piece of material in a direction substantially perpendicular to the path of free fall of said material and another crushing force being applied to said piece of material in a direction inclined with respect to said path of free fall, said respective forces being.V applied substantially simultaneously to said' piece of material at said opposite sides 'of said piece 'of material.

3. 'An apparatus for crushing materials' comprismg a pair of crushi'ngjaws each having a crushing surface, said surfaces being spaced apartin'opposed relation and deninga substantially'vertical crushing slit, means supporting each crushing' jaw for swinging movement toward the op'-,V posite jaw in a direction having a substantial horizontal component of'movementy'and means connected Ito'said jaws to swing 'said jaws substantiallysimultaneously" in` opposite directions relative to each other to apply a force couple to a piece of material. caught between'said crush# ing surfaces.

4. An apparatus for crushing. materials comprising a pair of elongated crushing jaws each having. a conveXly curved Acrushing surface, said' surfaces being spaced apart in opposed relation andldeiining a crushing slit 'narrower at the' bottom. than the'top of the slit whereby pieces of material to be crushed'may be suspended by said crushing.

surfaces, means supporting each' jaw fo'rrrepeated movement in a curved path 'having a 'substantial horizontal component of movement, said jaw surfaces being closest together when each jaw is at the center of its path of movement, and means connected to said jaws to move said jaws substantially simultaneously in opposite directions relative to each other to apply rapidly occurringfforce couples to'a piece'of material suspended by and between said jaw surfaces.-

5. An apparatus for crushing materialscomprisirig av pair of Acrushing jaws each having a crushing surface, said crushing surfaces being similarly' shapedrandspacednapart in opposedrelation' to defineV a funnel shaped' passage wider atthe'top than the bottom, a frame, substantially horizontal -support members' extending' from said.' frame, one of said support members being connectedto andsupportingV one of saidcrushing jaws for horizontal swinging movement' and another of said supporting members being connected' to and supporting theother of 'said' crushing force couplesareapplied toI a piece of material"loeate`d` in said passage and suspended by said crushing surfaces.

6.V An apparatus 'for crushing materialsA comprising a base, va pair of'upstanding substantially parallel frame members mounted on` said base, a .pair of spaced apart substantially parallel elastic plate'membersvconnected to and extendingina horizontal: direction substantially per-` pendicularly from each upstanding frame member,` a pair of crusher jaws, each Crusher jaw being connected to and supported-bye pair 'of platefmembe'rs, saidcrush'e'r jaws, when at'rest; being'substantially parallel to said frame members andbeing'disposed'opposite'each 'other to deline a crushing slit,A the discharge mouth of said crushingslit being-located above'said base, and means Vconnected to said jaws to oscillate said jaws substantially'simultaneously in oppositesubstantially horizontal directions relative to each other wherebyv a piece of material caught between said-jaws' is oscillated*rapidly'about itsv path "of free fall. said repeatedoscillationscausing said piece'of material to fracture into smaller pieces capable of free fall between said crushing jaws.

7. An apparatus for crushing materials comprisinga pairl of crushing jaws, said jaws Ibeing elongated ina hori-A zontal direction and having opposed similarly? shaped crushing surfaces 'dening a crushing slit narrowerat the bottom' than the top of said slit,'a pair of spaced apart substantially vertical frame members also elongated in a horizontal direction, said jaws beinglocated substantially midway between said-frame members, resilient'supporting means extending crossways betweenand connected to: each frame member and the crushing jaw closest to that frame member, and means connected to an end. of. each vcrush.-V

ing jaw`to swing each'erushing jaw in a horizontal path 81C' Y relative to the-frame' member from -which 'said jawlis supported, saidl supporting-'means causmgthevjaw supported thereby-"to"nrovel-in'a curved-substantially horizontal path.;I

8;-A'n apparatus;lfcrushihg'materials comprisingI a y pair tof rcrushing jaws,i ea'c'lr jaw: havinga crushingsurface,

said" surfaces 'bingmositionedadjacent eachv other and deining a crushing slit, means supportingl oneof sa1d jaws foi swinging movementf'in 'asubstantially horizontal direction; meanssupportin'g theother of said Jaws for swinging movement inf a'direction-'inclmed to the -hor1- zontal, andmeans 1 connected lto -sa-d jaws to swingsaid'- jaws substantially simultaneously so'that said crushing surfaces move pasteachiothe'rto impart-a twisting-forceV toV a piece of lmaterialcaught `between said crushing surfaces.

9. The method of crushing-'apiece ofmaterial which'V comprises the stepsof suspending said piece of material against free' fall by supporting ,said piece yof material at- 'substantially oppositesidescf said-'piece of material, land then applyingrapidly` occurring force couples to said p1ece v 10. The method-ofl crushing a piece of material-which" comprises thesteps ofsuspending said pieceof material" of movement extendingA both'tangentially'and Vinwardly with` respect to 'Said piece of material, and' said* supports being 'moved' yirropposite directionsl while they engage said' piece ofmaten'al to 'oscillatesaid piece' of material lin a rotary' mannerand'thereby' fracture it 'into` 'smaller pieces of material capable of freefall. j

11. The method 'of crushiug'a piece ofmaterial'which comprises the steps-of suspendingsaid piece ofV material*` maintaining a downwardforce'on said piece'of material' while the twisting squeezesarebeingapplied thereto.'

12; Anapparatus for crushing materials comprising an upstanding `frame member; a pair ofsubstantiallyparallel spaced apartresilent'supporting members each having oneend rigidly secured to said frame'member, said sup-I porting members extending substantially perp'endicularly from said framemember in a horizontal direction, al

crusher jaw rigidlysecu'red to each end of a reSilie'nt'supporting member which is opposite from the'end secured to said frame'membe'r. whereby said crushe'rpjaw is spaced from said frame member, said crushe'r jaw having a crush! ing surface facingaway from' said frame member, and means connected'to'said jaw to oscillate said4 jaw with respect to said frame member.

References Cited xin.A theiile of this patent. UNITED STATES PATENTS 531,680 Hannu'm' Jam 1, 1895 895,850 Gerstenhauer Aug.- 113 1908` 1,783,489'l Zeb Dec; 2, 1930- FOREIGN'PATENTS 34h Great-Britain of 1881 929,947 Germany Nov. 10, 1955 1,082,413 France .Tune 16, 1954

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