Patent Publication Number: US-9421547-B2

Title: Jaw crusher

Description:
TECHNICAL FIELD 
     The present invention relates to a jaw crusher, more particularly, but not exclusively, to a jaw crusher for crushing rock material. 
     BACKGROUND OF THE INVENTION 
     Quarried material is often processed by means of crushing plant, for the production of aggregate, for example. There are various known forms of crushing plant for the comminution of rock material and the like, one of which is referred to as a jaw crusher. 
     GB2387342 describes a known jaw crusher of the kind having a fixed jaw and a swing jaw disposed between opposing side walls of the jaw crusher, wherein the swing jaw is movable relative to the fixed jaw, for generating impelling forces to crush material present in a crushing chamber defined by between the two jaws. The jaw crusher includes a cross beam which extends through apertures in the opposing side walls, and a toggle plate is provided between a rear face of the swing jaw and the cross beam. An hydraulic cylinder is mounted in each of said side wall apertures, for applying a load to cross beam, which is transmitted to the swing jaw via the toggle plate. 
     A shim pack consisting of a plurality of removable shim plates is provided in each side wall aperture, between the front face of the cross beam and an end surface of the respective aperture, for setting and adjusting the normal working clearance between the lower end of the swing jaw and the fixed jaw. 
     Crushing forces generated during movement of the swing jaw are passed through the toggle plate against the cross beam and back to the hydraulic cylinders. However, the hydraulic cylinders are pre-pressurized to a predetermined value, for example 400 bar, against an end surface of the respective side wall apertures, through the cross beam and the shim pack, and thereby provide a pre-loaded reaction to the forces generated during movement of the swing jaw. 
     This provides a substantially compact design of jaw crusher, which has particular advantage for use as mobile plant. 
     If pressure generated during the crushing cycle becomes excessive, for example in an overload situation where an uncrushable object is present in the crushing chamber, the load applied to the cross beam via the toggle plate will exceed the pre-load pressure of the hydraulic cylinders. To address this, a relief valve is provided in an hydraulic circuit to the cylinders. This allows fluid under pressure to be released from the hydraulic cylinders, allowing the respective cylinder piston to be pushed backwards, to enable the swing jaw to move away from the fixed jaw and thereby to allow the crushing chamber to be cleared safely. 
     In order to adjust the spacing between the lower ends of the jaws, it is first necessary to release the pressure from the cylinder arrangements, to enable the pistons to retract. This relieves the load on the cross beam and allows safe removal of the shim packs. 
     The present invention provides a more adaptable jaw crusher arrangement. 
     SUMMARY OF THE INVENTION 
     According to the present invention there is provided a jaw crusher having a fixed jaw and a swing jaw disposed between opposing side walls of the jaw crusher, wherein the swing jaw is movable relative to the fixed jaw for generating impelling forces to crush material present between the two jaws. The jaw crusher includes a cross beam which extends between the opposing side walls, and a toggle plate is provided between a rear face of the swing jaw and the cross beam. Pressure cylinders (e.g. hydraulic cylinders) are provided for applying a load to the cross beam, to provide a reaction to forces generated during movement of the swing jaw. The jaw crusher further comprises a locking arrangement for selectively preventing substantial movement of the cross beam against the action of the hydraulic cylinders. 
     This novel arrangement provides a more adaptable jaw crusher, insofar as the locking arrangement gives the operator the option to maintain a pre-load in the cylinders even in the event of high crushing pressures. In GB2387342, the cylinder pressure is reduced, in order to relieve the excess load from the crushing chamber. This functionality may still be provided in a jaw crusher according to the above aspect of the invention. However, the locking arrangement allows the jaw crusher to be used to crush difficult materials without using a pressure relief arrangement. 
     In exemplary embodiments, the locking arrangement includes a locking member which is movable between a first position where crushing loads are transmitted from the crossbeam to the hydraulic cylinders and a second position where crushing loads are carried by the side walls of the jaw crusher. 
     The locking member may take the form of a mechanical spacer for locking the cross beam against rearward movement in the event of excess loads being generated during movement of the swing jaw. 
     In exemplary embodiments, the cross beam extends through apertures in the opposing side walls. Each aperture may include a first end stop against which a first face of the cross beam is to be driven by the hydraulic cylinders. 
     In exemplary embodiments, an hydraulic cylinder is mounted in each of said apertures for urging the cross beam in a first direction, e.g. against the first end stops. The action of the cylinders may be in line with the side walls. 
     In exemplary embodiments, each hydraulic cylinder includes a cylinder body and a piston which is movable relative to the cylinder body. The cylinder body may be mounted within a respective side wall aperture against a second end stop. 
     The locking arrangement may comprise a mechanical spacer to be positioned between a rear face of the cross beam and the cylinder body. In these embodiments, the spacer is configured for preventing substantial movement of the cross beam in the direction of said cylinder body. The result is that excess loads from the crushing chamber are transmitted from the cross beam to the side walls via the spacers, cylinder bodies and second end stops. 
     In exemplary embodiments, the spacer is configured to form a sleeve for at least a portion of the circumference of the piston. The sleeve may be substantially U-shaped. The sleeve may comprise at least one handle by which the sleeve can be manipulated. 
     The locking arrangement may be manually operable. 
     In exemplary embodiments, the jaw crusher further comprises an adjustment mechanism for the adjusting spacing between the jaws. The adjustment mechanism may be mounted in operative communication between the cross beam and the toggle plate, such that load is transmitted to the toggle plate via the adjustment mechanism during the application of load on the cross beam from the hydraulic cylinders. 
     The adjustment mechanism may comprise two wedges slidable with respect to one another for increasing or decreasing the jaw spacing. The adjustment mechanism may comprise at least one actuator configured to slide at least one of said wedges to increase or decrease the jaw spacing. 
     The adjustment mechanism is operable without the need to move the cross beam in a rearward direction and without needing to relieve the pressure applied through the cylinders. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       Other aspects and features of the invention will be apparent from the claims and following description of embodiments, made by way of example, with reference to the following drawings, in which: 
         FIG. 1  is a partially cross-sectional view through a jaw crusher in a first, unlocked state; and 
         FIG. 2  is a partially cross-sectional view through the jaw crusher of  FIG. 1  in a second, locked state. 
     
    
    
     DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS 
     With reference to  FIGS. 1 and 2 , a jaw crusher assembly is generally indicated at  10 . The jaw crusher assembly  10  includes a pair of jaws; a fixed jaw  14  and a swing jaw  16 . The jaws  14 ,  16  are of conventional construction and are each provided with a wear surface  20 . The wear surfaces  20  each define a crushing face on a respective jaw  14 ,  16 , and the two crushing faces define a crushing chamber  18  for receiving material to be crushed. 
     An upper end of the swing jaw  16  is connected to the jaw crusher assembly in a known manner by a shaft (not shown) rotatably received in a bearing (not shown). Rotation of the shaft causes circular motion of the upper end of the swing jaw  16  in the direction of the fixed jaw  14 . The mounting and movement of the upper end of the swing jaw  16  on the jaw crusher assembly  10  is wholly conventional and shall not be described in any further detail. 
     The jaw crusher assembly  10  includes a cross beam  22 . The cross beam  22  extends across a transverse axis of the jaw crusher assembly  10 . The ends of the cross beam  22  are received in elongate apertures (indicated generally at  24 ) in opposing walls  26  of the jaw crusher frame, e.g. in a manner generally as shown in GB2387342. 
     A toggle plate  28  is provided between the rear face of the swing jaw  16  and the cross beam  22  and is supported by toggle seats (not shown) at either end, e.g. in a manner generally as shown in GB2387342. 
     An hydraulic cylinder arrangement consisting, in this embodiment, of a pair of hydraulic cylinders  30 , in parallel, is provided for operative engagement with the rear face of the cross beam  22 . The hydraulic cylinders  30  are each received in a respective side wall aperture  24 . Hence, the action of the cylinders  30  is in line with the side walls  26 . 
     Each hydraulic cylinder  30  has a cylinder body  32  and a piston  34  operatively reciprocable within the cylinder body  32 . The cylinder body  32  has relief and supply lines connected to an hydraulic fluid circuit (not shown) via ports  36 ,  38  e.g. in a manner generally as described in GB2387342. The fluid circuit may include a relief circuit to enable the pressure in the cylinders to be relieved, e.g. in overload situations or if an uncrushable blockage is present between the jaws  14 ,  16 . 
     An adjustment mechanism  42  is provided between the front of the cross beam  22  and the toggle plate  28 . The adjustment mechanism is configured for setting or adjusting the spacing between the lower ends of the jaws  14 ,  16  so that a predetermined maximum product size may be produced during the crush cycle. 
     In this embodiment the adjustment mechanism takes the form of a pair of wedges  44  configured to be moved in relation to one another by actuators  46 , as described in more detail below. In this embodiment, the actuators  46  are hydraulic cylinders arranged for sliding the wedges  44  in and out in a transverse axis of the jaw crusher. 
     Each wedge  44  has a narrow end  48  and a wide end  50  separated by an inclined surface  52 . The wedges  44  are arranged alongside one another so that the narrow end  48  of one wedge  44  is proximal the wide end  50  of the other wedge  44 , and vice versa, so that together the wedges  44  define two parallel edges  54  that are also parallel to the front of the cross beam  22 . The parallel edges  54  are distance x (shown on  FIG. 2 ) apart—this is the distance between the cross beam  22  and the toggle plate  28 , which is adjustable as described below. 
     The wedges  44  can be moved in relation to one another by the hydraulic cylinders to increase or decrease the distance x. The hydraulic cylinders  46  are connected to the wide end  50  of each wedge  44 . The hydraulic cylinders  46  are configured to move the wedges  44  towards and away from one another to increase or decrease distance x. Increasing the distance x moves the toggle plate  28  and thus the swing jaw  16  towards the fixed jaw  14 , and so decreases spacing between the jaws  14 ,  16 . Similarly, decreasing the distance x will increase the spacing between the jaws  14 ,  16 . 
     In use, rotation of the shaft causes cyclic movement of the swing jaw  16  between a first position, in which the crushing face of the swing jaw  16  is inclined to the crushing face of the fixed jaw  14 , and a second position in which the crushing face of the swing jaw  16  is brought substantially parallel to the crushing face of the fixed jaw  14 , at a predetermined spacing from one another. Hence, in use, the crushing face of the swing jaw  16  moves in a crushing cycle, up and down, as well as towards and away from the crushing face of the fixed jaw  14 . Material to be crushed is introduced into the crushing chamber  18  through the top of the jaw crusher assembly  10  and crushed material is discharged through the spacing between the lower end of the two jaws  14 ,  16 . The cyclic movement of the swing jaw  16 , as described above, causes impelling forces for crushing the material present in the crushing chamber  18 . 
     In use, the hydraulic cylinders  30  are pressurised to a predetermined value, for example 400 bar. Accordingly, the cross beam  22  is forced under the action of the cylinders  30  against a stop, which in this embodiment is defined by an end surface  38  of the apertures  24 . Each cylinder body  32  is mounted within a respective side wall aperture  24  and acts against a further stop, in this embodiment formed by an end surface  40  and the opposite end of the aperture  24  to the end surface  38 , when the respective piston  34  is extended and in use to drive the cross beam against the first end stop  38 . 
     Hence, a pre-load is applied to the rear of the swing jaw, via the cross beam  23 , adjustment mechanism  42  and toggle plate  28 . As a crushing force is generated, e.g. during cyclic movement of the swing jaw  16  in the direction of the fixed jaw  14 , load from the crushing chamber  18  is transferred through the toggle plate  28  and adjustment mechanism  42  to the cross beam  22 , against the action of the hydraulic cylinders  30 . The hydraulic cylinders  28  hence provide a pre-loaded reaction to the applied load from the swing jaw to the cross beam  22 . 
     As in GB238742, the cylinder pressure may be reduced, in order to relieve excess loads from the crushing chamber. However, the jaw crusher  10  is provided with a locking arrangement for selectively preventing substantial movement of the cross beam  22  against the action of the hydraulic cylinders  30 . The locking arrangement gives the operator the option to maintain a pre-load in the cylinders  30  even in the event of high crushing pressures. The locking arrangement allows the jaw crusher to be used to crush difficult materials without using a pressure relief arrangement. 
     The locking arrangement includes two locking elements  56  configured to be manually inserted between the cylinders  30  and the rear face of the cross beam  22 . More particularly, the locking elements  56  are intended to define a mechanical spacer between the cross beam  22  and the cylinder body  32 , to prevent substantial rearward movement of the cross beam  22  against the action of the pistons  34 . 
     In this embodiment, the locking elements  56  take the form of a U-shaped sleeve, e.g. having two parallel arms  58  joined by a cross-piece (not shown), in order to sit around at least a part of the circumference of the piston  34  with a clearance. Two loop handles  60  extend outwardly from each cross-piece to allow easy manipulation of the sleeves  56 . 
       FIG. 1  shows the jaw crusher assembly  20  in an unlocked state, with the sleeves  56  removed from the assembly  10 . In  FIG. 2 , the jaw crusher assembly  10  is in a locked state by the insertion of the sleeves  56 , which serves to lock the position of the crossbeam (to prevent it moving rearwards against cylinder pressure. 
     The position of the crossbeam  22  remains substantially constant, even during the adjustment process, whereas the toggle plate  28  and the swing jaw  16  are moved as a result of movement of the wedges  44 . 
     In alternative embodiments (not shown) the locking arrangement is configured so that the sleeves  56  are inserted automatically rather than manually. 
     The novel arrangement described herein provides a more adaptable jaw crusher, insofar as the locking arrangement gives the operator the option to maintain a pre-load in the cylinders even in the event of high crushing pressures. In GB2387342, the cylinder pressure is reduced, in order to relieve the excess load from the crushing chamber. This functionality may still be provided in a jaw crusher described herein. However, the locking arrangement allows the jaw crusher to be used to crush difficult materials without using a pressure relief arrangement. The locking member is movable between a first position, e.g. disengaged from the cross beam and cylinder body, where excess crushing loads (i.e. in excess of the pre-load pressure) are transmitted from the crossbeam to the hydraulic cylinders, and a second position, e.g. engaged between the cross beam and cylinder body, where excess crushing loads are carried by the side walls of the jaw crusher, by transfer through the cylinder body and associated end stops in the side wall aperture. 
     The adjustment mechanism is operable without the need to move the cross beam in a rearward direction and without needing to relieve the pressure applied through the cylinders.