Patent Publication Number: US-7708218-B2

Title: Jaw crusher and self-traveling crusher

Description:
This application is a U.S. National Phase Application under 35 USC 371 of International Application PCT/JP2006/316552 filed Aug. 24, 2006. 
     TECHNICAL FIELD 
     The present invention relates to a jaw crusher and a self-propelled crushing machine having the jaw crusher. 
     BACKGROUND ART 
     Conventionally, a jaw crusher that crushes raw materials by swinging a swing jaw with respect to a fixed jaw is known. The fixed jaw and the swing jaw are supported by a crusher frame. Raw materials are thrown into a region surrounded by the fixed jaw, the swing jaw and the crusher frame, and then the swing jaw swings to crush the raw materials between the fixed jaw and the swing jaw. 
     Such a jaw crusher is arranged to receive reaction force from crushing of raw materials with a reaction force-receiving link mechanism. The reaction force-receiving mechanism substantially includes, for example, a link plate whose first end is engaged to a rear surface of the swing jaw, a toggle link that supports a second end of the link plate and rotates about a fixed link pin, and a lock cylinder whose lower end is connected to the toggle link (e.g., see Patent Document 1). 
     In the reaction force-receiving link mechanism, a rotational axis of the toggle link is a dual type toggle link pin, a pair of which are serially disposed along the width direction of the jaw crusher. An outer (first) end of each toggle link pin is supported by a side wall plate constituting a side surface of a crusher frame, and an inner (second) end is supported by a plate-shaped bracket standing on a cross member which connects the side wall plates on both sides. Since the first end of each toggle link pin is supported by the side wall plate, the toggle link pin can be pulled out from the side wall plate to the exterior, thereby facilitating maintenance. 
     [Patent Document] JP-A-2004-174450 
     DISCLOSURE OF THE INVENTION 
     Problems to be Solved by the Invention 
     Taking maintenanceability into consideration, the outer end of the toggle link pin is supported by the side wall plate, which happens to be provided with high strength as a portion of the crusher frame, so that the end can be supported with advantageous strength. 
     However, though a support structure can rigidly support the first end of the toggle link pin, since the inner second end is supported only by the plate-shaped bracket, the outer side and the inner side are not well-balanced with respect to strength, thereby requiring a thicker bracket for compensation, which is unsuitable for a compact jaw crusher that requires weight reduction. 
     An object of the present invention is to provide a jaw crusher which can keep maintenanceability by facilitating attachment and detachment of the toggle link pin and can support, in good balance, the outer side and inner side of the toggle link pin and a self-propelled crushing machine having such a jaw crusher. 
     Means for Solving the Problems 
     A jaw crusher according to an aspect of the present invention includes: a crusher frame that includes a pair of side wall plates and a rear wall plate and a cross member that connect the pair of the side wall plates; a fixed jaw attached to the rear wall plate; a swing jaw swingably hung between the side wall plates; and a reaction force-receiving link mechanism that includes: (i) a pair of toggle link pins having a first end pivoted on the side wall plate and a second end pivoted on a main supporter provided to the cross member, the pair of the toggle link pins being coaxially disposed, (ii) and (ii) a toggle link rotatably supported by the toggle link pins, in which the cross member on which the second end of the toggle link pin is pivoted is box-shaped. 
     In the above arrangement, it is preferable that the reaction force-receiving link mechanism includes a pair of lock cylinders whose pistons have a distal end that is rotatably coupled to the toggle link by way of a coupling shaft, the main supporter is provided to a side of the cross member adjacent to the swing jaw, and supporting portions that support cylinder bodies of the pair of the lock cylinders are provided to a side of the cross member opposite to the side to which the main supporter is provided. 
     In the above arrangement, it is preferable that the reaction force-receiving link mechanism includes a link plate having an end engaged to a rear portion of the swing jaw, and that a biasing mechanism that biases the link plate in a predetermined direction is provided to an outer side of the toggle link. 
     In the above arrangement, it is preferable that the reaction force-receiving link mechanism includes a pair of arms that supports the other end of the link plate and is rotatably supported by the pair of the toggle link pins, in which a coupling center of the lock cylinder relative to the coupling shaft is displaced axially inward with respect to a support center of the arm relative to the toggle link pin, and the biasing mechanism is disposed in a space created by the displacement between the side wall plates and the toggle link. 
     In the above arrangement, it is preferable that a self-propelled crushing machine includes the jaw crusher. 
     EFFECTS OF THE INVENTION 
     According to the aspect of the present invention as mentioned above, the outer end of the pair of the toggle link pins that support the toggle link is securely pivoted on the side plate, and the inner end is also securely pivoted not on a conventional plate-like bracket of a cross member but on the highly rigid, box-shaped main supporter integrally provided to the cross member, so that both ends of the toggle link pin can be supported well-balanced in strength without additional reinforcement, thereby enabling weight reduction. Obviously, since the outer end of each of the toggle link pins is supported by the side wall plate, the toggle link pin can be pulled out from the side wall to the exterior by removing the toggle link pin from the side wall plate, thereby still allowing easy maintenance. 
     According to the aspect of the present invention, as described above, since the cross member is formed box-shaped and high in rigidity, the cross member can serve as a supporting portion for the lock cylinders, so that there is no need for additional components to support the lock cylinders, thereby reducing the number of components constituting the jaw crusher. 
     According to the aspect of the present invention, since the biasing mechanisms are provided to the outer sides of the toggle link, the biasing mechanisms can be adjusted from the exterior of the jaw crusher, thereby facilitating adjustment. 
     According to the aspect of the present invention, the coupling center of the lock cylinder at the coupling shaft and the support center of the toggle link pin on the toggle link are misaligned to provide a space to dispose the biasing mechanism, so that the biasing mechanisms can be efficiently disposed to both sides of the toggle link, thereby providing secure support to the link plate. 
     According to the aspect of the present invention, functions and effects similar to the above-mentioned aspects of the invention can be obtained by installation of the jaw crusher according to the above-mentioned aspects of the present invention. 
    
    
     
       BRIEF DESCRIPTION OF DRAWINGS 
         FIG. 1  is a perspective view showing a self-propelled crushing machine according to an embodiment of the present invention. 
         FIG. 2  is a perspective view of a jaw crusher according to the embodiment. 
         FIG. 3  is a perspective view of the jaw crusher according to the embodiment. 
         FIG. 4  is a side sectional view of the jaw crusher according to the embodiment. 
         FIG. 5  is a side sectional view of the jaw crusher according to the embodiment. 
         FIG. 6  is a perspective view of the jaw crusher according to the embodiment. 
         FIG. 7  is a perspective view of a crusher frame assembled with a toggle link according to the embodiment. 
         FIG. 8  is a sectional view of the primary portion of the crusher frame and the toggle link, which is taken along VIII-VIII line in  FIG. 2 . 
         FIG. 9  is a sectional view of the crusher frame and the toggle link from another angle, which is taken along IX-IX line in  FIG. 2 . 
         FIG. 10  is a perspective view showing a whole of a cross member that constitutes the crusher frame. 
     
    
    
     BEST MODE FOR CARRYING OUT THE INVENTION 
     Brief Description of Overall Arrangement 
     An embodiment of the present invention will be described below with reference to the figures. 
       FIG. 1  is a perspective view showing a self-propelled crushing machine  1  according to the embodiment. For the convenience of explaining the embodiment, the right side of  FIG. 1  will be referred to as a front side and the left side as a rear side. 
     The self-propelled crushing machine  1  includes: a main unit  10  having a pair of lower traveling members  11 ; a feed unit  20  that is provided to a rear portion of an upper surface of the main unit  10  and supplied with raw materials; a jaw crusher  30  provided in front of the feed unit  20 ; a power unit  40  provided in front of the jaw crusher  30 ; and a discharge conveyor  50  extending forward and obliquely upward from a lower portion of the main unit  10  between a pair of crawlers  18 . 
     The main unit  10  has a main frame (track frame)  14  including left and right side frames each continuous in the longitudinal direction and a plurality of link frames linking the side frames to each other. The lower traveling members  11  are respectively attached on the lower sides of the side frames. The lower traveling member  11  is constructed in an arrangement in which the crawler  18  is wound around a front sprocket wheel  16  driven by a hydraulic motor  15  and a rear idler tumbler  17 . 
     The lower traveling member  11  of the present embodiment is not provided with upper rolling wheels. In the upper side of the lower traveling member  11 , the crawler  18  is guided sliding on a metallic guide plate with superior wear resistance. Accordingly, in the upper side of the lower traveling member  11 , the height level of the crawler  18  is lower than conventional models and the crawler  18  is substantially horizontal. Consequently, a maintenance opening  14 A provided to a side surface of the main frame  14  as an entrance into the interior is opened at a lower position as compared to conventional models, and the height of the main frame  14  is also set low. However, because the height from the upper surface of the discharge conveyor  50  to the bottom surface of the jaw crusher  30  is determined, the installation height of the jaw crusher  30  itself is substantially the same as that of conventional one. From another standpoint, the capacity of the main frame  14  which houses the lower portion of the jaw crusher  30  decreases as the height of the main frame  14  decreases, correspondingly increasing the portion of the jaw crusher  30  exposed to the exterior. A larger exposed portion reduces work that requires entry into the maintenance opening  14 A, thereby facilitating maintenance. 
     In the feed unit  20 , a grizzly feeder (not shown) driven by a vibrator  25  is mounted via a plurality of coil springs on the upper side of the frame protruding rearward. A hopper  26  is provided to the upper side of the grizzly feeder, covering the feeder from its three sides. Raw materials are thrown into the hopper  26  whose opening widens upward. Provided below the grizzly feeder is a discharge chute (not shown) which guides raw materials sorted and dropped by a grizzly feeder to the discharge conveyor  50  below. 
     As shown in  FIG. 1 , the power unit  40 , on which an engine, a hydraulic pump, a fuel tank, an operating oil tank and the like are mounted via suitable mounting brackets and cross members, is mounted on a main frame  14 . A control valve housed in a housing space of the power unit  40  distributes the hydraulic pressure from the hydraulic pump to the hydraulic motor in the lower traveling member  11 , the vibrator  25  for the grizzly feeder, the hydraulic motor of the jaw crusher  30 , a hydraulic motor for driving the discharge conveyor  50  and the like. 
     The discharge conveyor  50  discharges forward crushed materials dropped from the outlet of the jaw crusher  30  and drop them from a height. The dropped crushed materials are, for example, accumulated. If the raw materials contain foreign substances such as rebar and metal chips, a magnetic separator  28  (see  FIG. 1 ) can be mounted in front of the discharge conveyor  50  to remove the foreign substances. Instead of accumulating crushed materials from the discharge conveyor  50  on the ground, crushed materials may be carried to a remote place by secondary and tertiary conveyors and the like. 
     As shown in  FIGS. 2 to 6 , the jaw crusher  30  has a crusher frame  34  in which left and right side wall plates  31  are linked to each other by a rear wall plate  32  reinforced by a plurality of ribs and a cross member  33 . A fixed jaw  35  is attached to the inner surface of the rear wall plate  32 , and a swing jaw  36  whose tooth surface stands substantially vertically is disposed opposite to the fixed jaw  35 . The swing jaw  36  is hung at an upper side thereof on an eccentric portion of a main shaft  37  rotatably bridged between the side wall plates  31 , supported at a lower side thereof by a reaction force-receiving link mechanism  60  for receiving reaction force generated by crushing, and biased constantly toward the reaction force-receiving link mechanism  60  by a biasing mechanism  70 . 
     The reaction force-receiving link mechanism  60  includes a link plate  61  having a first end engaged on a rear part of the swing jaw  36 , a toggle link  64  that supports a second end of the link plate  61  and rotates about a toggle link pin  63 , and lock cylinders  65  having lower ends pivoted on the toggle link  64 . Each lock cylinder  65  is rotatably pivoted on the side of the cross member  33 . An outlet gap W between the lower ends of the jaws  35  and  36  can be adjusted by advancing and retracting rods  66  of the lock cylinders  65 . In other words, the reaction force-receiving link mechanism  60  constitutes an outlet gap-adjusting link mechanism  62  in which the lock cylinders  65  are driven to move the swing jaw  36  toward and away from the fixed jaw  35  via the toggle link  64  and the link plate  61 . 
     The biasing mechanism, a pair of which are disposed at two opposing sides of the reaction force-receiving link mechanism  60 , substantially consists of a tension rod  75  having an end pivoted on the side of the swing jaw  36  and a tension spring  74  biasing the tension rod  73  in a predetermined direction, as shown  FIG. 5 . The tension rod  73  and the tension spring  74  are attached to the above mentioned toggle link  64 . 
     In the jaw crusher  30  as described above, a crush chamber  34 A is formed by the region surrounded by the fixed jaw  35 , the swing jaw  36  and the crusher frame  34 , and when a pulley  38  provided to an end of the main shaft  37  is driven by a hydraulic motor via a V-belt, the swing jaw  36  functions as a swinging link via the rotation of the main shaft  37  and crushes raw materials in the crush chamber  34 A between the fixed jaw  35  and the swing jaw  36 . Meanwhile, in the jaw crusher  30  according to the embodiment, the reaction force-receiving link mechanism  60  adopts a down-thrust type mechanism, so that the swing jaw  36  swings upward from downside on approaching the tooth surface of the fixed jaw  35 . 
     Detailed Description of Jaw Crusher 
     The details of the jaw crusher  30  will be explained below. 
     In  FIGS. 2 to 6 , the jaw crusher  30  has the fixed jaw  35  fixed to the rear wall plate  32 , and the swing jaw  36  which swings relative to the fixed jaw  35 , as described above. Provided on the rear surface of the swing jaw  36  are the reaction force-receiving link mechanism  60  which receives reaction force from the swing jaw  36 , and the biasing mechanism  70  which biases the swing jaw  36  with a predetermined biasing force toward the reaction force-receiving link mechanism  60 . 
     The reaction force-receiving link mechanism  60  includes a link having the link plate  61 , the toggle link  64 , and the lock cylinders  65 , as described above. 
     As shown in  FIG. 3 , the link plate  61  is a plate-shaped member which contacts the rear surface of the swing jaw  36  throughout substantially overall width of the swing jaw  36 . The link plate  61  contacts the swing jaw  36  in an oblique downward direction from upside, so that the reaction force-receiving link mechanism  60  is of the down-thrust type. As shown in  FIG. 3 , an end of the link plate  61  contacts a contact portion  361  provided on the rear surface of the swing jaw  36 . The other end of the link plate  61  contacts contact portions  641  provided on the toggle link  64 . Thus, the link plate  61  is pinched and supported between the swing jaw  36  and the toggle link  64 . Concave portions  362  and  642  each having a substantially arc-like section are formed on the contact portions  361  and  641 . The link plate  61  can swing about swinging centers which are the centers of the arcs of the concave portions  362  and  642 . 
     The toggle link  64  provided inside the side wall plates  31  integrally includes an attachment portion  644  to which the tension spring  74  is attached. The toggle link  64  is pivoted on the toggle link pin  63 . 
     Each of the lock cylinders  65  is provided in front of the toggle link  64  and provided with the rod  66  and a cylinder body  67  for advancing and retracting the rod  66 . Each lock cylinder  65  is arranged to stand with the rod  66  situated in the lower side of the cylinder body  67 . The lower ends of the rods  66  are respectively pivoted on the front ends of the toggle link  64 . A portion of each cylinder body  67  near the end thereof through which the rod  66  advances and retracts, i.e., the lower side (head side) of the cylinder body is rotatably supported by a support portion  331  of the cross member  33 . 
     In each of these lock cylinders  65 , the rod  66  or a piston at an end of the rod  66  interference-fits the cylinder body  67 , and both of the rod  66  and the cylinder body  67  are usually locked. If hydraulic pressure is applied to the interference-fitted portions through the rods  66 , the circumferential walls of the cylinder bodies  67  expand, reducing resistance between the cylinder bodies  67  and the rods  66 . The lock is then released so that the rods  66  can advance and retract relative to the cylinder bodies  67 . Therefore, the rods  66  can be locked at any suitable position in the cylinder bodies  67 . 
     According to the reaction force-receiving link mechanism  60 , the reaction force generated when raw materials are crushed is received by the toggle link pin  63  of the toggle link  64  and the support portions  331  of the cross member  33  via the link plate  61 . As described above, if hydraulic pressure is applied between the pistons and the cylinder bodies  67  of the lock cylinders  65  to release the lock and if the rods  66  are advanced and retracted, the swing jaw  36  is moved toward and away from the fixed jaw  35  via the toggle link  64  and the link plate  61 . In short, the reaction force-receiving link mechanism  60  also functions as the outlet gap-adjusting link mechanism  62 . 
     As shown in  FIG. 5 , a pair of the biasing mechanisms  70  are provided to both outer sides of the toggle link  64 , or in other words, to both sides in width direction of the swing jaw  36 . As mentioned above, the biasing mechanism  70  includes the tension rod  73  and the tension spring  74 . 
     A first end of the tension rod  73  is attached to the swing jaw  36 . A second end of the tension rod  73  is arranged to penetrate the attachment portion  644  of the toggle link  64  into a forward and obliquely upward direction with respect to the position of the attached first end. The tension rod  73  is inserted into the tension spring  74 , whose top end contacts a contact portion  731  screwed on the tension rod  73  and bottom end contacts a contact portion  732  fixed to the attachment portion  644 , thereby biasing the tension rod  73  toward the toggle link  64  with a predetermined biasing force (tension). In short, the tension spring  74  biases the swing jaw  36  toward the toggle link  64  via the tension rod  73 . This biasing force steadily holds the link plate  61  between the swing jaw  36  and the toggle link  64 . 
     On the inner surface of the side wall plate  31 , a cheek plate  311  is attached to the substantially triangular region between the fixed jaw  35  and the swing jaw  36 . The cheek plate  311  is formed in a plate of predetermined thickness, which is divided into upper and lower plates. At both widthwise ends of the of the fixed jaw  35 , projections  39  ( FIG. 7 ) for guiding the cheek plate  311  are obliquely formed, downwardly approaching the swing jaw  36 . The cheek plate  311  is contacted to and guided by the projection  39  to roughly determine position thereof with respect to the side wall plate  31  and is mounted on the side wall plate  31  by a mounting bolt  312 . A head of the mounting bolt  312  is housed in a notch  313  formed on the cheek plate  311  so as not to project from the surface of the cheek plate  311 , thereby reducing direct rubs between raw material and the mounting bolt  312 . 
     The swing jaw  36  includes a swing jaw body  363  supported rotatably with respect to the main shaft  37  and moving teeth  364  attached to the swing jaw body  363 . As shown in  FIGS. 4 to 6 , a wedge  80  for fixing the moving teeth  364  to the swing jaw body  363  is provided between the moving teeth  364  and the swing jaw body  363 . A wedge bolt  83  that penetrates the swing jaw body  363  to the side opposite to the surface on which the wedge  80  is mounted is inserted in the wedge  80 . The wedge  80  is biased toward the swing jaw body  363  by a spring  84  attached to a distal end of the wedge bolt  83 . 
     Detailed Description of Toggle Link Support Structure 
     Hereinafter, a support structure at the crusher frame  34  of the toggle link  64  constituting the reaction force-receiving link mechanism  60  will be described. 
       FIG. 7  is a perspective view of the crusher frame  34  assembled with the toggle link  64  according to the embodiment.  FIG. 8  is a sectional view of the primary portion of the crusher frame  34  and the toggle link  64 , which is taken along VIII-VIII line in  FIG. 2 .  FIG. 9  is a sectional view of the crusher frame  34  and the toggle link  64  from another angle, which is taken along IX-IX line in  FIG. 2 .  FIG. 10  is a perspective view showing a whole of the cross member  33  that constitutes the crusher frame  34 . 
     As shown in  FIGS. 7 to 10 , the crusher frame  34  includes a pair of the side wall plates  31 , the rear wall plate  32  for connecting the side wall plates  31  and the cross member  33 . A pair of the toggle link pins  63  for pivoting the toggle link  64  are serially provided on a common widthwise axis of the crusher frame  34 . An outer end  63 A of each of the toggle link pin  63  is pivoted on the side wall plate  31  of the crusher frame  34 , and an inner end  63 B is pivoted on a portion of the cross member  33 . A support block  314  that can spare sufficient length to support the end  63 A of the toggle link pin  63  is fixed to the inner side of the side wall plate  31  by welding and the like. 
     A flange  63 C of the outer end  63 A of the toggle link pin  63  is fixed to the side of the side wall plate  31  by a bolt. The toggle link pin  63  can be pulled out to the exterior by removing the bolt and can also be inserted from the exterior. In other words, as shown in  FIGS. 2 ,  3  and  6 , the toggle link pin  63  is disposed above a mounting rib  31 B provided on the side wall plate  31 . When the jaw crusher  30  is mounted by mounting the mounting rib  315  on the upper portion of the main frame  14 , the toggle link pin  63  is exposed to a position allowing attachment and detachment thereof from the exterior. 
     The toggle link  64  is a cast with a hollow portion, which includes: a body  645  whose upper surface has an opening for weight reduction and lower surface has an opening  64 B for sand removal; a pair of arms  646  extending forward from the body  645 ; and a support piece  647  extending substantially straight rearward from the body  645 . 
     The body  645  is disposed substantially in the middle of the side wall plates  31 . Between the body  645  and the left and right side wall plates  31 , spaces sufficient to dispose tension rods  73  of the biasing mechanisms  70 , tension springs  74  and attachment portions  644  for attaching the tension rods  73  and the tension springs  74  are reserved. 
     The arms  646  extend forward and widthwise, and the distal ends of the arms  646  are supported by the toggle link pins  63 . In other words, the support holes  648  are provided to the distal ends of the arms  646 , the toggle link pins  63  are inserted into the support holes  648  via the liners  649 . 
     The coupling shaft  650  to which the lower ends of the rods  66  of the lock cylinders  65  ( FIG. 8 ) are coupled are inserted into the support pieces  647 . 
     Accordingly, since the arms  646  extend forward and widthwise with respect to the body  645  and the support pieces  647  extend straight forward, the coupling centers C 2  of the coupling shafts  650  are located inward relative to the support centers C 1  of the toggle link pins  63 , so that the misalignment of the centers C 1  and C 2  allows reservation of spaces on both sides for disposing the above-mentioned biasing mechanisms  70 . By providing the biasing mechanisms  70  to both sides of the toggle link  64 , the link plate  61  ( FIG. 3 ) can be properly supported at both widthwise ends, so that an eccentric load that originates from crushing is less likely to generate force that twists the toggle link  64 , thereby stabilizing the link plate  61 . 
     The cross member  33  is also a hollow cast and includes: a tubular body  330  that is fitted to the attachment opening  31 A provided to the side wall plates  31  on both sides and then, for example, welded around; and a main supporter  332  that extends obliquely downward from the body  330  and supports the inner ends  63 B of the toggle link pins  63 . As shown in  FIG. 9 , openings  330 A on both sides of the body  330  are sealed, for example, by welding seal plates  333 . As already mentioned, the support portion  331  for supporting the lock cylinders  65  are provided to the rear side of the body  330 . 
     In such a wholly hollow cross member  33 , the main supporter  332  for supporting the toggle link pin  63  is formed in a box to improve rigidity around the support hole  334  provided to the main supporter  332 . More specifically, the main supporter  332  includes both side surfaces  335  having the support holes  334 , an upper surface  336  covering an area between the upper ends of the side surfaces  335 , and a lower surface  337  covering an area between the lower ends of the side surfaces  335 . The upper surface  336  and the lower surface  337  are continuously connected via a curved surface  338  at the front side. Due to such an improvement in rigidity, the support strengths of the inner end  63 B and the outer end  63 A of the toggle link pin  63  are substantially equalized, so that the ends  63 A and  63 B of the toggle link pin  63  are supported in a well-balanced manner. 
     Since the main supporter  332  is box-shaped and high in rigidity, providing thickness around the support hole  334  on the side surface  335  to support the toggle link pin  63  is sufficient, so that other portions, i.e., the upper surface  336 , the lower surface  337  and the curved surface  338  can be formed thinner compared to the thickness around the support hole  334  on the side surface  335  to enable weight reduction. In addition, the entirely hollow cross member  33 , despite overall deformed box shape thereof, enables weight reduction by overall thinning of the surfaces and high rigidity. Therefore, twist or the like of the cross member  33  on account of the reaction force generated by crushing can be securely prevented, thereby improving the preciseness of the crushed particle size. 
     Further, since the coupling center C 2  at the coupling shaft  650  of the lock cylinder  65  takes an inner position relative to the support center C 1  of the toggle link pin  63 , in the cross member  33  over the coupling center C 2 , the distance between the two support portions  331  supporting the lock cylinders  65  are shortened, thereby averaging external force inputted to each of the pair of the lock cylinders  65  to eliminate induction of excessive slides of the lock cylinders  65 . Furthermore, although loads are likely to concentrate due to the shortened distance between the two support portions  331  of the cross member  33 , since the cross member  33  is extremely high in rigidity owing to the overall box shape thereof, durability against such loads is ensured and flexure of the crusher frame  34  is restrained, thereby curbing variations in the crushed particle size. 
     Operation of Jaw Crusher 
     The operation of the jaw crusher  30  will be explained below. 
     At this time, since the swing jaw  36  is supported at its lower side by the reaction force-receiving link mechanism  60  of the down-thrust type, the link plate  61  swings about the arc center of the concave portion  642  on the side of the toggle link  64  so that the swing jaw  36  swings to move toward and away from the fixed jaw  35 . By this swinging movement, the swing jaw  36  and the fixed jaw  35  crush raw materials thrown between them and discharge crushed materials to the discharge conveyor  50  from the outlet gap W between the lower ends. 
     The reaction force received when the swing jaw  36  crushes raw materials is received by the toggle link pin  63  of the toggle link  64  and the support portion  331  of the cross member  33 . If the reaction force received by the swing jaw  36  is too large, the interference-fitted portions of the lock cylinders  65  slide to prevent damages to the main portions of the jaw crusher  30 . 
     Meanwhile, to change the particle size of crushed materials, the outlet gap-adjusting link mechanism  62  is operated. Hydraulic pressure is applied between the piston and the cylinder body  67  of the lock cylinder  65  to slightly expand the cylinder body  67  to reduce resistance therebetween and release the interference-fitted lock. When the rod  66  is advanced and retracted in this state by applying hydraulic pressure to the head side or bottom side of the cylinder body  67 , the toggle link  64  rotates about the toggle link pin  63  in response. The link plate  61  then changes position thereof, so that the swing jaw  36  moves toward and away from the fixed jaw  35 . The outlet gap W between the lower ends of the swing jaw  36  and the fixed jaw  35  is thus adjusted to change the particle size of the crushed materials. 
     When a necessity arises to remove the toggle link  64  from the crusher  30  to conduct maintenance, first, the toggle link  64  is supported by a temporary stand or the like to allow removal of the biasing mechanism  70 , and then the coupling shaft  650  to which the lower portion of the lock cylinder  65  is coupled is pulled out to the outer side to release the coupling. Next, the toggle link pin  63  is pulled out to the outer side to be left in a free state. Subsequently, the toggle link  64  is displaced backward together with the temporary stand. The procedure is reversed to attach the toggle link  64 . As described, maintenance can be conducted by removing only the toggle link  64  without removing the whole jaw crusher  30  from the main frame  14 . 
     It should be noted that the present invention is not limited to the above embodiment, but includes other arrangements that can achieve an object of the present invention, and modifications described below are also included in the present invention. 
     For example, in the above embodiment, the coupling center C 2  at the coupling shaft  650  of the lock cylinder  65  took a position inner relative to the support center C 1  of the toggle link pin  63 , but an arrangement in which the centers C 1  and C 2  share a position with respect to left-right direction (width direction) is included in the present invention. However, when the centers C 1  and C 2  take a common position, disposing the biasing mechanisms on both sides of the toggle link  64  requires increasing a distance between the side wall plates  31  and a length of the toggle link pin  63 , thereby leading to upsizing. Accordingly, from a viewpoint to promote downsizing, the centers C 1  and C 2  are preferably displaced to dispose the biasing mechanisms  70  in the space created by the displacement. 
     The best arrangements, methods and the like for implementation of the present invention is disclosed above, but the present invention is not limited to such. That is to say, though the present invention is specifically shown in figures and explained mainly with regard to a particular embodiment, those skilled in the art can variously modify the shape, amount and other detailed arrangements of the above embodiment without departing from the technical ideas and scope of the objects of the present invention. 
     Therefore, because the above-disclosed description limiting the shape, amount and the like is merely an exemplified statement for facilitating understanding of the present invention and is not a limitation on the present invention, a statement using names of the members on which a part of or all of the limitations regarding the shape, amount and the like is eliminated is included in the present invention.