Abstract:
A jaw crusher where the tension rod includes an electronically-controlled hydraulic pre-load and an automatically releasable pre-load whenever adjustments to the size of the material output are made, together with a remote visual indicator of the setting of the size of the material output.

Description:
CROSS REFERENCE TO RELATED APPLICATIONS 
     This application is a continuation of application Ser. No. 11/079,352 filed on Mar. 14, 2005, by the same inventors, and entitled “Jaw-Type Rock Crusher With Toggle Plate Tension Bar”. This application is incorporated herein in its entirety by this reference. 
    
    
     FIELD OF THE INVENTION 
     The present invention generally relates to jaw-type rock crushers, and more particularly relates to jaw crushers having a toggle plate and spring tension rod, and even more particularly relates to such spring tension rods with hydraulics. 
     BACKGROUND OF THE INVENTION 
     In the past, rock crusher designers have endeavored to improve the ease of operating and adjustment of jaw-type rock crushers. While many improvements have been made to reduce the effort associated with adjusting such crushers, adjustment of such crushers often remains a non-trivial task. Most jaw-type crushers usually have a fixed jaw and a large heavy movable jaw known as a pitman which is driven by an eccentric shaft which causes the pitman to move along a non-circular path. 
     Typically, the bottom of the pitman is supported by a piece of metal called the toggle plate. It serves the purpose of allowing, within limits, the bottom of the pitman to move up and down with the motion of the eccentric shaft, as well as serve as an overload protection mechanism for the entire crusher. Should a piece of non-crushable material such as a steel loader tooth (sometimes called “tramp iron”) enter the jaw of the crusher and be larger than the maximum allowed size for passing through the jaw (the output material size setting), it can&#39;t be crushed nor pass through the jaw. In this case, the toggle plate is designed to collapse and prevent further damage to the rest of the crusher. 
     Adjustment of the location of the toggle plate effectively adjusts the output material size setting. A common approach to adjusting the location of the toggle plate is to use a pair of reversed overlapping wedges which are hydraulically actuated so that when maximum overlap occurs, the output material size setting is at a minimum. 
     A tension rod is typically included to maintain contact between the pitman and the movable toggle plate in an effort to reduce wear on these components. 
     These tension rods have various types of construction. One type of tension rod used in the past has been a spring coupled to a threaded rod and nut combination. Adjustment of the nut can adjust the tension applied. Others have used hydraulic cylinders with an accumulator to essentially effectuate an adjustable “hydraulic spring.” Other hybrid designs have used hydraulic or pneumatic power to maintain a constant pressure applied to a spring. 
     While these and other types of tension rods have improved the operation of a jaw crusher, they do have several drawbacks. 
     First of all, all types of spring-loaded tension rods generally make it more difficult to manipulate the overlapping wedges due to the high spring forces. 
     The hydraulic cylinder with an accumulator often results in leakage at the hydraulic seal owing to the very rapid movement of the tension rod. 
     The hybrid types of tension rods may require a manual release of the hydraulic pressure therein to reduce the pressure, thereby making it easier to manipulate the overlapping wedges. 
     Consequently, there exists a need for improved methods and systems for tensioning a toggle plate and a pitman in an efficient manner. 
     SUMMARY OF THE INVENTION 
     It is an object of the present invention to provide a system and method for adjusting the output material size setting and maintaining the tension between a pitman and a toggle plate of a jaw-type rock crusher in an efficient manner. 
     It is a feature of the present invention to utilize a hydraulic pre-loaded spring tension rod. 
     It is an advantage of the present invention to provide an easily adjustable spring tension rod that provides a constant (within limits) tension between the toggle plate and the pitman irrespective of the output material size setting of the crusher. 
     It is another feature of the present invention to include a pressure sensing device to create an electronically controlled hydraulic system which maintains the pressure within the hydraulic cylinder portion of the tension rod within predetermined limits. 
     It is another advantage to permit automatic re-pressurization of the hydraulic pre-load within predetermined limits. 
     It is yet another advantage of the present invention to permit automatic shutdown of the crusher if the pressure of the hydraulic pre-load is improperly set to an excessively high level. 
     It is another feature of the present invention to include an automatic reduction in the hydraulic pre-load pressure whenever the overlapping wedges are being manipulated to change the output material size setting of the crusher. 
     It is another advantage of the present invention to permit easier adjustment of the output setting of the crusher, thereby allowing smaller and more compact hydraulic cylinders to manipulate the overlapping wedges. 
     It is yet another feature of the present invention to include a remote visual indicator of the separation between the fixed jaw and the bottom of the pitman, which determines the output material size setting. 
     It is another advantage of the present invention to provide for quick, easy and accurate hydraulic adjustment of the output material size setting. 
     The present invention is a hydraulically pre-loaded spring apparatus and method for adjusting the output material size setting of jaw-type crushers, designed to satisfy the aforementioned needs, provide the previously stated objects, include the above-listed features, and achieve the already articulated advantages. The present invention is carried out in a “wasted time-less” manner in a sense that the time required to manually release pressure on the tension rod hydraulic cylinder and the time required to check and maintain the proper pressure in the tension rod hydraulics, has been eliminated. The invention is also an accumulator-less system in the sense that a typical hydraulic accumulator which creates a “hydraulic spring” is not employed. 
     Accordingly, the present invention is a system and method including a jaw crusher which utilizes at least one of the following: an electronically controlled and/or automatically releasable hydraulic pre-loaded spring tension rod together, and a remote visual indicator of the output material size setting. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       The invention may be more fully understood by reading the following description of the preferred embodiments of the invention, in conjunction with the appended drawings wherein: 
         FIG. 1  is a cross-sectional elevation view of a jaw crusher of the prior art, employing a spring-type tension rod and nut locking assembly. 
         FIG. 2  is a close-up elevational view of a hydraulic adjusting tension rod assembly of the prior art which shows an accumulator coupled to the tension rod by a hose or pipe. 
         FIG. 3  is a perspective view of the jaw crusher of the present invention. 
         FIG. 4  is a close-up cross-sectional view of the lower portion of the jaw crusher of  FIG. 3 . 
         FIG. 5  is a partially cut-away perspective view of the lower portion of the jaw crusher of  FIG. 3 . 
         FIG. 6  is a schematic circuit diagram of the hydraulic and electrical systems of the present invention. 
     
    
    
     DETAILED DESCRIPTION 
     Now referring to the drawings wherein like numerals refer to like matter throughout, and more specifically referring to  FIG. 1 , there is shown a jaw rock crushing system of prior art generally designated  100 , including a fixed jaw  102  which typically is firmly mounted to a support structure. Pitman  104  is shown disposed next to fixed jaw  102 . Pitman  104  is well known, and it moves around eccentric shaft  106 . It is possible that a cam may be used instead of an eccentric shaft. It is also possible that in some situations, the fixed jaw  102  may be replaced with a second pitman. The discussion herein is focused upon a single pitman jaw crusher, but novel aspects of the present invention are intended to apply to crushers having multiple pitmans. 
     Pitman  104  is adjacent to toggle plate  108 , which is adjacent to output material size setting adjusting wedge mechanism  120 . Also shown is a tension rod assembly  110  having a tension rod to pitman connection  112 , a tension rod  114 , a tension rod spring  116 , a tension rod end cap  117 , and a tension rod adjusting nut  118 . 
     Now referring to  FIG. 2 , there is shown a lower portion of a jaw crusher of the prior art, such as one made by Automatic Welding Machine and Supply Co. of Kitchener, Ontario Canada.  FIG. 2  shows a pitman  204  and a toggle plate  208  which are believed to be functionally very similar to pitman  104  and toggle plate  108  respectively of  FIG. 1 . Also shown in  FIG. 2  is a hydraulic spring tension rod assembly  210 , which includes an accumulator  230  and an accumulator connection line  232 . Note that this device has an attachment at one end to the pitman  204  and at a midpoint support  211 , while the spring and hydraulic elements are located outside of the two support points for the hydraulic spring tension rod assembly  210 . 
     Now referring to  FIG. 3 , there is shown a jaw crusher of the present invention, generally designated  300 , which includes a fixed jaw  302  and pitman  304 . As stated above, the fixed jaw  302  may be replaced in some situations with a second pitman to achieve a dual pitman jaw crusher. It is the intention of the present invention to apply to multiple pitman jaw crushers as well. The pitman  304  is coupled to eccentric shaft  306  in a well-known manner. Also shown is toggle plate  308 , as well as the outside end of the hydraulically preloaded spring tension rod assembly  310 , which is shown below the output material size setting adjusting wedge mechanism  320 . The hydraulically preloaded spring tension rod assembly  310  is shown having a tension rod assembly retaining pin  342 , which is shown at the terminal end of hydraulically preloaded spring tension rod assembly  310 . The location of the support of hydraulically preloaded spring tension rod assembly  310  at both ends thereof provides for some of the advantages of the present invention. The motion of the terminal end of the prior art device shown in  FIG. 2  may be considered to be excessive. In the prior art design of  FIG. 2 , the terminal end will swing significantly because of the significant distance between its terminal end and the support  211 . Shown adjacent to the hydraulically preloaded spring tension rod assembly  310  is remote visual indicator of output setting  340 . The end of the rod of remote visual indicator of output setting  340  is shown protruding from the support structure at the end of the hydraulically preloaded spring tension rod assembly  310 . The amount that this end protrudes indicates the crusher material gap or the output material size setting. This rod may have markings thereon which aid in measuring the extent of the protrusion and, therefore, the output material size setting. Also shown is hydraulic output adjusting controls  350  which are located in a position that the remote visual indicator of output setting  340  is easily visible when the hydraulic output adjusting controls  350  are being manipulated. 
     Now referring to  FIG. 4 , there is shown a close-up cross-sectional view of the lower portion of the crusher of the present invention, generally designated  400 . The hydraulically preloaded spring tension rod assembly  310  is shown having a tension rod connecting rod  402  which couples to the pitman  304  and to the tension rod hydraulic pre-load piston  408 . Also shown is the spring  404  which provides the desired tension force. The hydraulically preloaded spring tension rod assembly  310  has a tension rod assembly outside enclosure  406 , which is coupled at one end via tension rod assembly retaining pin  342  to the frame of the crusher or in some embodiments, to the toggle plate  308  or the output material size setting adjusting wedge mechanism  320  or its support structure. Tension rod assembly outside enclosure  406  is a load bearing member as it structurally couples the pitman to a fixed location on the crusher, through the hydraulically preloaded spring tension rod assembly  310 . Since the tension rod assembly outside enclosure  406  is a load bearing structure, the hydraulically preloaded spring tension rod assembly  310  would be inoperable if the tension rod assembly outside enclosure  406  were removed. This results in an advantageous increase in safety. Hydraulically preloaded spring tension rod assembly  310  includes a tension rod hydraulic pre-load mechanism  407  which is essentially a hydraulic cylinder which is adjusted to accommodate the differing location of the bottom of the pitman  304  when it is adjusted to different output material size settings by the toggle plate  308  and output material size setting adjusting wedge mechanism  320 . The tension rod hydraulic pre-load mechanism  407  is capable of being released when necessary to facilitate ease of use of the output material size setting adjusting wedge mechanism  320 . 
     The hydraulically preloaded spring tension rod assembly  310  is supported at one end by the pitman  304 , and at the other end, by tension rod assembly retaining pin  342 . The entirety of the hydraulically preloaded spring tension rod assembly  310  is located between these supports, and this eliminates any large protrusions which extend substantially beyond the end of the support structure associated with the hydraulically preloaded spring tension rod assembly  310 . 
     Remote visual indicator of output setting  340  is shown coupled at visual indicator connection point  440  to the tension rod connecting rod  402 . The displacement of the spring does not affect the location of the end of the rod of the remote visual indicator of output setting  340 . 
     Now referring to  FIG. 5 , there is shown an alternate view of the crusher of the present invention, generally designated  500 . In  FIG. 5 , the tension rod assembly outside enclosure  406  has been removed, as well as a cover on output material size setting adjusting wedge mechanism  320  so as to expose the underlying mechanisms. Shown are output material size adjusting first wedge  502  and output material size adjusting second wedge  504 . The cylinder to actuate these wedges is smaller than in many prior art crushers and is located with the structure labeled as output material size setting adjusting wedge mechanism  320 . 
     One of the advantages of the present invention is achieved by the use of tension rod assembly deformable retaining clip  506  which couples to tension rod assembly retaining pin  342  and fits in a slot in the support structure. Tension rod assembly deformable retaining clip  506  has a tension rod assembly deformable retaining clip back end  508  which extends behind the support structure. However, if the toggle plate  308  is collapsed and excessive forces are applied to hydraulically preloaded spring tension rod assembly  310 , the tension rod assembly deformable retaining clip back end  508  will bend straight, and the hydraulically preloaded spring tension rod assembly  310  will drop out of the slot. This dropping out of the slot will prevent expensive damage to the hydraulically preloaded spring tension assembly  310  and also will be apparent to the operator, who can shut down the crusher and make necessary repairs and replacements. 
     Now referring to  FIG. 6 , there is shown a schematic diagram of the hydraulics of the present invention, generally designated  600 . Hydraulic output adjusting controls  350  are shown, as well as high pressure sensitive check valves  604 , which are hydraulically coupled to pilot to open check valve  606  and flow diverting valve  608 , which are triggered by the pressure associated with high pressure sensitive check valve  604  but release the pressure associated with the tension rod hydraulic pre-load mechanism  407 . The wedge manipulating hydraulic cylinder  602  is shown as well. It can be readily seen that when the wedge manipulating hydraulic cylinder  602  is actuated by hydraulic output adjusting controls  350 , the high pressure associated with that actuation is applied via high pressure sensitive check valves  604  to the pilot to open check valve  606  and flow diverting valve  608  which release the pressure on the tension rod hydraulic pre-load mechanism  407 , thereby making it easier for wedge manipulating hydraulic cylinder  602  to move the wedges. 
     Also shown is the optional accumulator  610  which performs the function of providing for a more constant pressure in line  611  as a result of leaks, etc. without the need to command the pump  630  to adjust for every detected pressure drop. The structure which performs this function may be a hydraulic/pneumatic accumulator as is well known in the art or a suitable substitute. 
     Also shown is the accumulator isolating check valve  612  which performs the function of allowing the accumulator  610  to maintain the pressure in line  611  without bleeding the pressure in the accumulator  610  out to the pump  630 . The structure which performs this function may be a simple check valve with a predetermined pressure level needed to keep it closed or open depending upon the particular arrangement of components or a suitable substitute. 
     Also shown is the manual pressure release valve  614  which performs the function of releasing pressure in the cylinder of mechanism  407  during servicing. The structure which performs this function may be a plunger operated check valve or a suitable substitute. 
     Also shown is the adjustable pressure reducing valve  616  which performs the function of setting the desired pre-load on tensioning mechanism  407 . The structure which performs this function may be a pressure reducing valve or a suitable substitute. 
     Also shown is the unloading valve  618  which performs the function of diverting pump flow, after the tensioning cylinder is loaded, instead of continuing to build pressure, so as to reduce horsepower requirements. The structure which performs this function may be a pilot actuated spool valve or a suitable substitute. 
     Also shown is the pressure sensing device  620  which performs the function of measuring and aiding in the reporting of the pressure in the hydraulic line  611 . The structure which performs this function may be a pressure transducer which generates an electronic signal representative of the pressure in line  611 , or it may be a similar sensing apparatus or it may even be a pressure gauge which provides a visual indication of the pressure in line  611  to a human operator of the system of the present invention. 
     The pressure sensing device  620  provides its electronic output signal on line  622  to electronic controller  640 . 
     Electronic controller  640  performs the function of receiving information relating to the pressure in line  611  and other lines if so desired, and generating a command on line  642  to drive the pump  630  to increase the pressure in line  611 . 
     Electronic controller  640  may be the microprocessor as mentioned herein, or it may be an electronic device with more limited capabilities such as a gate array or other dedicated circuitry to perform the limited functions of maintaining pressure in line  611  within certain predetermined limits and disabling the entire jaw crusher if so desired. 
     It should be understood that not all of the advantages of the present invention require the use of an electronic controller  640 . Indeed some of the advantages of the present invention can be achieved with an embodiment where the pressure sensing device is a gauge and a human operator inspects the gauge and controls a pump in response to the pressure indicated by the gauge. 
     The linkages herein are described as being hydraulic linkages; however, it is contemplated that other types of linkages could be substituted such as mechanical, electrical, pneumatic, or a combination thereof. 
     The term “pre-load” is used herein to refer to the application of hydraulic forces to address the differing location of the hydraulically preloaded spring tension rod assembly  310 , depending upon the output material size setting. 
     The term “pitman” is used herein to refer, as it is well known in the rock crushing industry, to mean the moving jaw in a jaw crusher which moves around in an eccentric path. This definition is not necessarily intended to be consistent with the usage of the term in the automotive industry, where it often refers to a connecting rod. 
     It is thought that the method and apparatus of the present invention will be understood from the foregoing description and that it will be apparent that various changes may be made in the form, construct steps, and arrangement of the parts and steps thereof, without departing from the spirit and scope of the invention or sacrificing all of their material advantages. The form herein described is merely a preferred exemplary embodiment thereof.