GB2190856A

GB2190856A - Crushing apparatus

Info

Publication number: GB2190856A
Application number: GB08710012A
Authority: GB
Inventors: Ian Gordon Rodger
Original assignee: Individual
Current assignee: Individual
Priority date: 1986-05-14
Filing date: 1987-04-28
Publication date: 1987-12-02
Also published as: CN87103586A; GB2190856B; CN1010285B; NZ216183A; GB8710012D0

Abstract

A crusher, for example for rock or the like, has crushing jaws 15,16 which are driven to swing towards and away from each other simultaneously in a parallelogram like movement and are pivoted to a frame adjacent the ends of the jaws for eccentric movement with regard to at least one of shafts 17,17a, so that most of the jaw movement is in a horizontal direction and is therefore a substantially balanced assembly. <IMAGE>

Description

SPECIFICATION Crushing apparatus Background of the invention (a) Field of the invention This invention relates to crushing apparatus.

The apparatus ofthe present invention is useful for crushing rock, and will be described with particular reference to this application. However, the apparatus also is useful for crushing other materials (e.g. glass, minerals, bricks, grains).

(b) Prior art Crushing at present is carried out in a numberof types of apparatus:- ball mills, rod mills, hammer mills and jaw crushers. However, for 'accu rate' crushing i.e. crushing material to obtain particles within a narrow size range, and with relativelyfew fines, a jaw crusher commonly is used. In the most commonly used designs, the jaw crusher crushes by a hammer-and-anvil type of action:- a moving jaw is swung against a stationary jaw. The position of the stationary jaw can be adjusted to alter the minimum gap between the jaws. This type of crusher gives good results, but is rather wasteful of power because a great deal ofthe force of the moving jaw is absorbed by the stationary jaw rather than by the material being crushed.In consequence, the apparatus requires a heavy support, to endure the uneven load on the apparatus imposed bythe impacts on the stationaryjaw. Such a jaw crusher is shown and described in Australian patent 227301 and in US patents 2326316 and 4124170.

Several prior patents have attempted to overcome this problem by designing crushers in which both jaws are driven. For example US patent 427441 discloses a crusher with two vertically arranged jaws with a gap between them, each jaw being pivoted adjacent its base. The jaws are driven adjacenttheir upper ends in such a mannerthatthe jaws move with a simultaneous rocking movement in the same direction, so that material between the jaws is wedged between the jaws and subjected to a grinding and crushing action due to the relative movement of one crushing surface upwards while the other crushing surface moves downwards. One major drawback ofthis design is that material between the jaws is ground between the jaws rather than being struck by jaws and this greatly reduces the impact of the force which can be exerted by the jaws.Also, much of the power supplied for driving the jaws is wasted in moving the jaws up and down, ratherthan in causing the jaws to strike the material to be crushed.

US patent 472367 discloses a crushing mill in which a pair of opposed jaws are mounted at their lower ends for a rolling movement about bearing rollers. The jaws are driven eccentrically towards and away from each other, so that one jaw always has a faster movement relative to the otherjaw, and there is a constant change in the opposing surfaces ofthe pair of jaws.However, this eccentric movement means that the jaws do not impact equally on material to be crushed, and the design has the further drawbackthatthe roller-mounting of the jaws constrains the lower ends of the jaws to remain in the same position, and means thatthejaws are not free to swing in a parallelogram-like motion, so that side-loads on the jaws are transmitted directly to the supporting housing of the mill, rather than being absorbed by the jaws themselves.

US patent 3079096 discloses a design of crusher broadly similar two that of US patent472367, in that a pair jaws is mounted at its lower end for vibratory motion, the lower end of each jaw being supported and restrained by a resilient mounting. In use, the jaws are vibrated towards and away from each other, but are not free to swing in a parallelogram-like motion, sothatthis design hasthedrawbacks described with reference to US patent472367.

In an endeavour to overcome the above desribed drawbacks, the present applicant designed the crusher the subject of New Zealand patent no: 196191, in which a pair of opposed crushing jaws are pivotally mounted so that they are free to swing from side to side in a parallelogram-like manner, and thus avoid transmitting major reaction forces to the supporting housing. The jaws are driven simultaneously towards each other and away from each other by a suitable driving means adjacent the free ends ofthe jaw. This design has been found to be extremely satisfactory for many applications, but for some applications (especially those in which some of the boulders being crushed are close to the maximum size which the crusher can accept) it has been found that this crusher has some drawbacks.In particular, boulders of, or close to, the maximum size, require more even crushing, along the full length ofthejaws. Also, damp material tends to pack between the jaws and can be difficultto dislodge.

Object ofthe invention An object ofthe present invention is to provide a crusher which overcomes the above described disadvantages of the prior art crushers. In particular, the present invention provides a crusher which possesses all the advantages of the crusher of NZ patent 196191 but which has the additional advantages of improving the overall crushing capacity ofthe crusher by permitting the crusher to crush over the full length of each jaw, and in which the jaws can move in such a manner asto dislodge material packed between the jaws.

Statement ofinvention The present invention provides a crusher including a pair of opposed crushing jaws, each jaw being pivotally mounted upon a supporting means for pivotal movement towards and away from the other jaw; the pivotal mounting of each jaw being adjacent one end of said jaw, said one ends of said jaws being Icoated opposite each other and the other ends of said jaws being located opposite each other; first driving means for driving said jaws to pivot towards each other simultaneously and away from each other simultaneously whilst allowing the jaws to pivot simultaneously in the same direction; and second driving means for driving said one end of at least one jaw towards and away from said one end of the other jaw.

Preferably, said jaws are arranged to form the facing walls of a downwardly convergent hopper.

Said one ends of said jaws may be located adjacentthetopofthecrusher,and said otherends of said jaws adjacent the bottom ofthe crusher.

Alternatively, said other ends ofthejaws may be located adjacentthetop ofthe crusher, and said one ends adjacent the bottom ofthe crusher.

The first driving means may comprise a single driving means, ortwo independent driving means, one connected to each jaw.

One or both of said one ends of the jaws may be driven, and if both are driven, saidsecond driving means may be a single driving means ortwo independent driving means.

Thefirstand second driving means may be independent or may be synchronised with each other.

Detailed description of the preferred embodiment Byway of example, a preferred embodiment of the present invention is described with reference to the accompanying drawings, in which: Figure I is an end view ofthe apparatus of the present invention, Figure2 is a side view of the apparatus of Figure 1, with part oftheframe member removed, Figure3is a section along the line Ill-Ill in Figure 2, Figure4is an end view of partof Figure 3, and Figure 5is a section on line V-V of Figure 2.

Referring to the drawings, a rock crushing apparatus comprises a frame 10 in the form of a table having atop 11 and legs 12. On the frame top 11 two pairs of crusher jaw pivot bearings 13, 14 are provided. Both pairs of pivot bearings 13, oppose each other across the top 11. Two jaws 15, 16 face each other, each jaw 15,16 has a horizontal shaft 17, 1 7a extending from each side of its upper end; the ends of each shaft 17,1 7a are pivotally secured to the pivot bearings 13,14. The two jaws 15, ofthe crusher are therefore suspended opposite each other from the top 11.

The shaft 17a which is connected to thejaw 16 is also journalled in a pair of eccentric bearings 40 which engage the adjacent portion of the rearface of thejaw 16 in known manner (Figure 5).

A pulley 41 is mounted on one end ofthe shaft 17a, and when said pulley is driven (as hereinafter described), the shaft 1 7a is rotated in the eccentric bearings 40, causing the jaw 16to move eccentrically towards and away from the jaw 15,adjacentthe upper ends ofthejaws.

Other possible constructions (not illustrated) are to mounttheshaft 17 in eccentric bearings, instead of or as well as the shaft 17a, so that either or both of thejaws 15,16, may be driven for eccentric movementtowards and away from each other adjacent the upper ends of the jaws. Also, the eccentric journals may be omitted, and either or both of the shafts 17a may be formed as eccentric shafts,togivethe required eccentric movement of the upper ends of the jaws 15 and/or 16.

Preferably, the inner surfaces of the crusher jaws are protected bywearig blocks 18, which optionally may be made with a plurality of ribs 19 on their working surface. The ribs 19 may decrease in depth towards one end. The inner crushing surfaces of the blocks 18 may be lined with hard alloy steel to reduce wear.

The wearing blocks 18 may be clamped, screwed or otherwise fastened to the jaws 15, 16 and may be invertable.

The jaws 15, 16 are spaced wider at the top than the bottom and two vertical end walls 20,21 are welded, one all to the end edge of each jaw and with the free end of each wall 20,21 close to the adjacent end edge ofthe otherjaw 15,16. Thus jaw 15 and wall 20 move together and jaw 16 and wall 21 move together, the arrangement being such that a "V" shaped hopper is formed by the end walls and jaws. When the crusher is operating, material to be crushed is fed into the top ofthe hopper, falls under gravity through the crusher, and leaves the bottom of the crusher in its crushed condition.

The end walls 20,21 could be welded to opposite endsofonejaw 15,16 and have small gaps adjacent the ends ofthe otherjaw 16,15 but such an arrangement would destroy the balance and symmetry of the arrangement described above.

The lower ends of the jaws 15, 16 are joined by a reciprocating mechanism which causes both the crusherjawsto swing simultaneouslyabouttheir pivot bearings 13, 14. The reciprocating mechanism causes the jaws to come together at the sametime and moveapartatthesametime; each jaw is moved with the same force. The reciprocating movement is provided by eccentrics 22 on a driving shaft 23, which is mounted horizontally in two bearings 24 secured to the outer surface at the lower end of the jaw 15. The driving shaft 23 extends beyond the width ofthe jaw 15 andtwo connecting rods 26 are mounted on the eccentrics 22.The otherends ofthe connecting rods 26 are mounted on similarly disposed eccentric journals 27 on a cross-shaft 28 which is mounted horizontally in bearings 29 secured to the lower end of the other jaw 16, parallel to the driving shaft 23 on the jaw 15.

AV-belt drive pulley 30 is secured to the end of the driving shaft 23, and this pulley 30 is driven from a motor (not shown) in known manner. When the pulley 30 is driven, it rotates the driving shaft 23, so thatthe eccentric journals on the shaft 23 cause the jaw 15 to swing towards and away from the jaw 16.

At the same time, the connecting rods 26 are reciprocated by the shaft 23 and cause the jaw 16to swing towards and away from the jaw 15. The connecting rods 26 and the shaft 23 are designed such that the lower ends ofthejaws 15 and 16 move away from each other and towards each other simultaneously, each jaw moving with the same velocity.

The pulley 41 may be driven from the pulley 30, or independently.

In normal operation, the connecting rods 26 do not move on the eccentrics 27 but are clamped to the shaft 28 by clamps 31 screwed to the connecting rods 26 and releasable from the shaft 28 by screws 32.

When the shaft 28 is unclamped it may be partially rotated in the connecting rods 26, whereby the eccentrics 27 adjustthe distance between the axes of the shafts 23, 28 and thus enablethe gap between the lower ends ofthejaws 15, 16to be altered. The clamps 31 are then re-tightened.

The distance between the upper ends of the jaws 15,16 may be altered, independently ofthe lower ends of the jaws, for example by unbolting the bearings 13, 14from thetop 11 and repositioning them using different (unshown) bolt holes in the top 11.

Instead of using the eccentrics 27, the distance between the bottom of the jaws 15, 16 can be changed by using connecting rods of adjustable length, for example in theform ofaturnbuckle having right and left hand threads.

For some purposes, it may be preferred to invert the arrangement shown in the drawings, so that although the hopper still tapers downwardly, the upper ends of the jaws 15, 16 are reciprocated and the lower ends of the jaws are pivotally mounted on the frame and one or both of said lower ends is eccentrically driven.

It is an important feature of the present invention that the jaws 15, 16 can swing about their pivot bearings 13, 14 in a parallelogram-like motion and are not rigidly secured to the crusher frame. To achieve this, the drive shaft 23, pulley 30 and connecting rods 26 all can swing with the jaws and since the driving belt (not shown) from the motor to the pulley 30 is flexible, it does not restrict the movement of the jaws.The ability ofthe jaws 15, 16 to swing simultaneously in a parallelogram-like manneravoids major reaction forces upon the crusher frame, so that during operation ofthe crusher the major proportion of the force of each jaw is transmitted to the material being crushed rather than to the opposite jaw, and there is little transfer of any forces to the crusher frame, and then only through the bearings 13, 14, it follows from this that (ignoring the eccentric drive to the upper ends of the jaws 15, 16) the centre of gravity of each jaw assembly has little vertical movement compared with the horizontal movement.Thus, there is little vertical vibrating force transmitted to the frame 10, and the horizontal forces are largely balanced out, thereby greatly increasing the efficiency of the crusher. However, the eccentric drive to the upper end ofthe jaw 15 and/or 16 introduces a somewhat greater component of vertical motion ofthatjaw:- this has the advantage of dislodging any material which has compacted between the jaws, since the downwards motion of the or each eccentrically-driven jaw tends to break up and dislodge any such compacted material.

When the embodiment of the invention shown in the drawings is in use, material to be crushed is poured into the top of the crusher (e.g. from a hopper). The lower ends of the jaws 15 and 16 pivot towards and away from each other simultaneously, and the upper end of jaw 15 also moves eccentrically towards and away from the upper end of jaw 16 (or, if both jaws are driven eccentrically, both jaws move towards and away from each other at their upper ends.) The degree of movement ofthe eccentrically-driven end ofthe or each jaw may be adjusted by adjusting the orientation ofthe eccentric bearings 40.

The eccentric motion of the upper end of the or each jaw will pre-crack large boulders and thus overcomes the problem of large boulders (close to the maximum size which the crusher can accept) being squeezed out of the crusher when the lower edges of the jaws move towards each other, the additional crushing given by the eccentric movement of the upper end of the or each jaw also tends to increase the overall crushing efficiency of the crusher. As discussed above, the eccentric motion ofthe upper end of the or each jaw also tends to dislodge material compacted between the jaws.

Although it is desirable (for the reasons discussed above) that the jaws 15,16 can swing in a parallelogram-like motion, it may be desirableto damp this swinging somewhat, and if this is required, the jaws 15, may be biassed towards a central position relative to the frame buy a spring means such as an elastomeric bush 33 which is fastened in a block 34 bolted to the legs 12. The bush inner is fastened to a torsion arm 35 which is connected buy a pivoted linkto the jaw 16. This biassing arrangement does not prevent the jaws from swinging in a parallelogram-like manner, but damps this swinging motion and tends to centre the jaws.

The above described crusher may be varied in a number of ways. Firstly, the drives to the upper and lower ends ofthe jaws 15 and 16 may be replaced by any other suitable drives e.g. the eccentric shaft 23 could be replaced by a plain shaftjournalled in eccentric bearings, andthe plain shaft 17 and eccentric jo u rna Is 40 could be replaced by an eccentric shaft.

Secondly, the upper and lower end of each jaw may be driven independently, instead of by a connected drive, and the non-pivoted ends of each jaw also may be driven independently of each other, by suitable synchronized drives.

Thirdly, the eccentric drive to the pivoted end of the or each jaw could be timed with reference to the drive to the non-pivoted ends of each jaw e.g. by using a chain and sprocket drive or a geared drive or atoothed belt drive.

Claims

1. Acrusherincludinga pair of opposed crushing jaws, each jaw being pivotally mounted upon a supporting means for pivotal movement towards and away from the other jaw; the pivotal mounting of each jaw being adjacent one end of said jaw, said one ends of said jaws being located opposite each other and the other ends of said jaws being located opposite each other; first driving means for driving said jaws to pivot towards each other simultaneously and away from each other simultaneously whilst allowing the jaws to pivot simultaneously in the same direction; and second driving means for driving said one end of at least one jaw towards and away from said one end of the other jaw.

2. The crusher as claimed in claim 1 wherein said jaws are arranged to form the facing walls of a downwardly convergent hopper.

3. The crusher as claimed in claim 2 further comprising two facing end walls which extend from jawto jaw with one end wall at each end of the jaws.

4. The crusher as claimed in Claim 3 wherein one end wall is secured rigidly to one end edge of one jaw andextendswith a small clearance pastthe opposing end edge of the other jaw, and the other end wall is secured rigidly to one end edge ofthe otherjawand extends with a small clearance past the opposing end edge of said one jaw.

5. The crusher as claimed in any preceding claim wherein the jaws have opposed working faces which bear against material passing through the crusher, in orderto crush the material, and said working faces are formed by removable and replaceable wearing blocks.

6. The crusher as claimed in claim wherein at least one of said working faces is formed with a plurality of parallel grooves extending towards an outletforcrushed material.

7. The crusher as claimed in claim 6 wherein the depth of said grooves decreases from one end ofthe grooves to the other end.

8. The crusher as claimed in any preceding claim wherein said first and second driving means are synchronised with each other.

9. The crusher as claimed in any preceding claim wherein said one ends of said jaws are located adjacent the top ofthe crusher and said other ends of said jaws are located adjacent the bottom ofthe crusher.

10. The crusher as ciaimed in any of claims 1 -8 wherein said other ends of said jaws are located adjacent the top of the crusher and said one ends of said jaws are located adjacentthe bottom ofthe crusher.

11. The crusher as claimed in any preceding claim wherein the pivotal mounting of one jaw can be moved towards and away from the pivotal mounting ofthe otherjaw.

12. The crusher as claimed in any preceding claim wherein the jaws are resiliently biassed towards a central working position.

13. The crusher as claimed in any preceding claim wherein said one end of each jaw is drivable towards and away from said one end of the other jaw.

14. Thecrusherasclaimed in claim 13wherein said second driving means comprises a single driving means arranged to drive both jaws.

15. Thecrusherasclaimed inclaim 13wherein said second driving means comprises two independent driving means connected one to each jaw.

16. The crusher as claimed in any preceding claim wherein said first driving means comprises two independent driving means connected one to each jaw.

17. Thecrusherasclaimed in any one of claims 1-15 wherein said first driving means comprises a single driving means arranged to drive both jaws.

18. The crusher as claimed in claim 17 wherein said first driving means includes a drive shaft rotatably mounted on one of said jaws, the drive shaft being formed with an eccentric portion, a connecting rod pivoted at one end to the eccentric portion and atthe other end to the otherjaw,the connecting rod being pivoted to the drive shaft and the other jaw remote from the pivotal mounting of the jaw.

19. The crusher as claimed in any preceding claim further comprising means for adjusting the minimum gap between said other ends of the jaws when said jaws are swung together.

20. The crusher as claimed in claim 19when dependent upon claim 18 wherein said means for adjusting the minimum gap comprise meansfor adjusting the distance between said pivots at the ends of the connecting rod.

21. The crusher as claimed in claim 17 wherein said first driving means includes: a drive shaft rotatably mounted on one of said jaws, the drive shaft being formed with an eccentric portion at each end thereof: a first connecting rod pivoted at one end to one said eccentric portion and at the other end to the other jaw; a second connecting rod pivoted at one end to the other said eccentric portion and atthe other end to the other jaw; both said connecting rods being pivoted to the drive shaft and to the otherjaw remote from the pivotal mounting of the jaw.

22. The crusher as claimed in claim 21 further including means for adjusting the minimum gap between said other ends of the jaws when said jaws are swung together.

23. The crusher as claimed in claim 22 in which said means for adjusting said minimum gap includes a further shaft pivoted on the said other jaw parallel to the drive shaft, the further shaft being formed with a further eccentric portions, the said other ends of the connecting rods being rotatable on the further eccentric portions and clampablethereon,whereby partial rotation of the further shaft within the connecting rods will adjust the distance between said pivots thereof.

24. The crusher as claimed in any preceding claim wherein said second driving means includes an additional drive shaft rotatably mounted on the or each driven jaw adjacent the pivotal mounting thereof, said shaft being mounted in eccentric bearings on the or each said jaw such that rotation of said shaft causes said jaw to move eccentrically towards and away from said otherjaw.

25. The crusher as claimed in claim 24 wherein said eccentric bearings are adjustable relative to said additional drive shaft so asto adjust the amount of movement of the or each said jaw towards and away from said other jaw.

26. The crusher as claimed in anyoneofclaims 1 -23 wherein said second driving means includes an additional drive shaft formed with an eccentric portion thereon and rotatably mounted on the or each driven jaw adjacent the pivotal mounting thereof, such that rotation of said shaft causes said jaw to move eccentrically towards and away from the other jaw.

27. A crushersubstantially as hereinbefore described with reference to and as shown in the accompanying drawings.