Abstract:
In the operation of work machines having an ejector blade pivotally coupled to a cylinder by cylinder-attached pivot pins, it has been a problem reducing the stress acting on the pivot pins caused by, for one example, improperly set yaw rollers. The present invention provides for an ejector arrangement for a work machine in which a coupler is pivotally coupled to the cylinder and pivotally coupled with the ejector blade.

Description:
This application claims the benefit of prior provisional patent application Ser. No. 60/217,613 filed Jul. 11, 2000. 
    
    
     TECHNICAL FIELD 
     The present invention relates generally to a an ejector arrangement for a work machine, and more specifically to a mounting apparatus used to couple an ejector blade to a hydraulic cylinder. 
     BACKGROUND 
     Work machines are used in earth moving operations to move material, such as dirt and rocks, from one location to another. An example of the aforementioned type of work machine is the ejector truck often advantageously utilized in those application in which space constraints limit or prohibit the raising of a truck bed such as is required for a conventional dump truck. Typically, the bed portion of an ejector truck remains attached to the bed portion chassis. An ejector blade is moveably mounted within the truck bed and is coupled to a hydraulic ram or cylinder comprising a plurality of sequentially extendable and retractable individual segments. The cylinder is typically coupled to the ejector blade by two trunnions or pivot pins disposed on opposite sides of the cylinder and co-linearly oriented, thereby allowing rotation of the ejector blade, relative to the cylinder, about an axis generally parallel with the floor of the bed. An example of such a cylinder coupling arrangement is shown in Patent Cooperation Treaty publication WO 99/15357 published on Apr. 1, 1999. 
     One drawback of prior art ejector-type work machines is the potential damage to the aforementioned trunnions caused by either an uneven load in the bed portion or, during ejector blade retraction, an obstruction contacting the ejector blade causing a tendency of the ejector blade to rotate about a substantially vertical axis substantially located at the point of attachment of the ejector blade with the hydraulic cylinder. To assist in preventing the aforementioned rotation, adjustable yaw rollers are typically provided on the ejector blade-mounted carriage portion to slidably engage the side walls of the truck bed. However, damage to the aforementioned trunnions and/or cylinder may result upon improper yaw roller adjustment requiring the trunnions to bear these loading conditions until the improperly adjusted yaw roller or rollers engage the side walls of the truck bed, thereupon transferring these loads to the truck bed. The present invention is directed to overcome one or more of the problems as set forth above. 
     SUMMARY OF THE INVENTION 
     In one aspect of the present invention, there is provided an ejector arrangement for a work machine of the type having a receptacle. The ejector arrangement includes an ejector blade, a cylinder, and a coupler pivotally coupled to the cylinder and pivotally coupled with the ejector blade. 
     In another aspect of the invention, a method of attaching a cylinder to an ejector blade in a work machine is provided. The method consists of pivotally attaching a first coupler member to a cylinder about a first longitudinal axis. The method also consists of providing a second coupler member attached with the ejector blade and pivotally attached to the first coupler member about a second longitudinal axis. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     FIG. 1 is a diagrammatic elevation view, in partial cut-away, of a work machine having the arrangement of this invention. 
     FIG. 2 is a diagrammatic elevation view of the ejector arrangement of this invention. 
     FIG. 3 is a diagrammatic sectional view taken along lines  3 — 3  of FIG.  2 . 
     FIG. 4 is a diagrammatic sectional view taken along lines  4 — 4  of FIG.  3 . 
     FIG. 5 is a diagrammatic sectional view taken along lines  5 — 5  of FIG.  3 . 
    
    
     DETAILED DESCRIPTION 
     With reference now to the Figures, a work machine is shown generally at  100  having an attached receptacle or bed portion  101  for holding materials to be transported to another location for unloading. To assist in removing the material from the bed portion  101 , the work machine  100  is provided with an ejector arrangement  102  of the present invention which includes an ejector blade  104  coupled to the bed portion  101  by a multi-stage hydraulic ram or cylinder  105  which moves the ejector blade  104  relative to the bed portion  101 . The ejector blade  104  is typically supported adjacent its bottom portion  108  by at least one roller  109  which moves across the floor  112  of the bed portion  101 . The overall shape of the ejector blade  104  is such that it substantially conforms to the shape of the bed portion  101 . 
     The ejector blade  104  is further attached to a carriage assembly  113  which slidably engages the side walls  114  of the bed portion  101  in response to movement of the cylinder  105 . A pair of yaw rollers  115 , attached to opposing sides of the carriage assembly  113 , assists in maintaining proper orientation of the ejector blade  104  within the bed portion  101  by slidably engaging the side walls  114  in response to any tendency of the ejector blade  104  to pivot about an axis substantially normal to the bed portion  101 . Activation of the cylinder  105  of the type described herein initiates a sequential elongation of the cylinder  105  causing a forcible contact between the materials deposited into the bed portion  101  and the ejector blade  104 , with a continual elongation of the cylinder  105  resulting in the ejection of the materials from the bed portion back end  117 , typically through a tailgate  120 . Upon the ejection of the materials from the bed portion  101 , the cylinder  105  may be reversibly operated causing retraction of the ejector blade  104  to bed loading position substantially as shown in FIG.  1 . 
     The cylinder  105  is secured at one end  123  to a bracket  124  which is pivotally carried on the bed portion  101  for pivotal movement in a vertical plane in response to the extension and retraction of the cylinder  105 . The ejector arrangement  102  of the present invention includes a coupler  125  used to couple the ejector blade  104  with the cylinder  105 . As shown best in FIG. 2, the coupler  125  of the present invention consists of a first coupler member  200  pivotally attached to the cylinder  105 , and a second coupler member  201  pivotally attached to the first coupler member  200  and attached with the ejector blade  104 . 
     With reference now to FIG. 3, the first coupler member  200  comprises an upper member  300  and a lower member  301  both fixedly connected to two side members  304  spaced a sufficient distance apart to accommodate the cylinder  105  therebetween. A mounting flange  305  is preferably fixedly attached to the upper and side members  300 , 304  on opposing sides of the first coupler member  200 . The first coupler member  200  is pivotally attached to the cylinder  105  by use of a pair of substantially co-linear first pivot pins  308 , each preferably fixedly attached with the cylinder  105 , both of which define a first longitudinal axis designated herein by reference numeral  309 . As will be apparent to those skilled in such art, providing the aforementioned pivotal attachment allows for rotation of the ejector blade  104 , relative to the cylinder  105 , in the general direction of arrows  312 , 313 . Each first pivot pin  308  is secured to a respective side member  304  by a removable bushing cap  316  preferably attached to each side member  304  by the use of preferably two fasteners  317 . 
     Each of the upper and lower members  300 , 301  are provided with substantially co-linear second pivot pins  320 , both defining a generally vertical second longitudinal axis designated herein by reference numeral  321 . Each respective second pivot pin  320  is used to pivotally attach the second coupler member  201  to the first coupler member  200 , thereby allowing for rotation of the ejector blade  104  relative to the cylinder  105  in the general direction of arrows  324 , 325 . It is preferred that each respective axis  309 , 321  be substantially orthoganally oriented, relative to one another, thereby allowing the ejector blade  104  to pivot, relative to the cylinder  105 , about both the vertical and horizontal axis  321  and  309 . 
     As should be apparent to those skilled in such art, an advantage of providing the ejector blade  104  with the ability to rotate, relative the cylinder  105 , about the second longitudinal axis  321  is that potentially damaging stresses which would otherwise be borne by the fist pivot pins  308  due to, for example, improper adjustment of one or more yaw rollers  115  are minimized until such time as ejector blade  104  rotation causes the yaw rollers  115  to engage the side walls  114 , thereby transferring the aforementioned stresses to the side walls  114 . 
     With reference now to FIG. 4, the second coupler member  201  preferably comprises an upper bearing assembly  400  and a lower bearing assembly  401  each pivotally mounted to a respective second pivot pin  320 . As shown, the ejector blade  104  of the type described herein typically comprises a plurality of lateral support members with two such adjacent lateral support members designated herein as upper lateral support member  404  and lower lateral support member  405 . Each respective bearing assembly  400 , 401  is preferably fixedly attached to, respectively, the upper and lower lateral support members  404 , 405  by use of mechanical fasteners  408 . 
     With reference now to FIG. 5, a bottom view of the coupler  125  is shown attached to the cylinder  105  and ejector blade  104  with the lower lateral support member  405  removed for clarity. As shown, the first coupler member  200  is preferably resiliently mounted to the ejector blade  104  by use of preferably a pair of resilient mounting structures  500 . Each resilient mounting structure  500  comprises a fastener  501 , having a head portion  504 , preferably threadably attached to a vertical ejector blade support structure  505 . Each respective fastener  501  is structured and arranged for reciprocative placement within an aperture  508  provided in each respective mounting flange  305 . An upper resilient member  509 , preferably comprising a resilient bushing made of rubber or other elastomeric type material, is concentrically placed about the fastener  501  substantially between each mounting flange  305  and head portion  504 . Also provided is a lower resilient member  512  also preferably comprising a resilient bushing made of rubber or other elastomeric type material. As shown, the lower resilient member  512  comprises an enlarged portion  513 , substantially interposed between the mounting flange  305  and the ejector blade  104 , and a reduced portion  514  interposed between the fastener  501  and aperture  508 . 
     To add increased stability to the resilient mounting structures  500 , a substantially rigid sleeve  516  may be concentrically placed between the fastener and each respective resilient member  509 , 512 . In addition, a washer  517  may be provided as shown and coupled to the fastener  501  preferably between the head portion  504  and upper resilient member  509 . Furthermore, shims  518  may be placed between the lower resilient member  512  and the vertical ejector blade support structure  505  in order to assist in properly aligning the coupler  125 , cylinder  105 , and ejector blade  104 . 
     As should be appreciated by those skilled in such art, upon either ejecting materials unevenly loaded in the bed portion  101  or the ejector blade  104  encountering an obstacle (not shown) in the bed portion  101  offset from the cylinder centerline  521 , the ejector blade  104  may yaw or rotate about the second longitudinal axis  321  which, if undamped or otherwise compensated for, may create a noisy and potentially damaging resonant yaw effect. 
     Industrial Applicability 
     With respect to the drawings and in operation, the ejector arrangement  102  of the present invention includes an ejector blade  104 , movably mounted within the bed portion  101 , by use of the cylinder  105 . A coupler  125  pivotally couples the ejector blade  104  to the cylinder  105  about two substantially orthogonal axis of rotation  309 , 321 . The horizontal or first longitudinal axis  309  advantageously permits the ejector blade  104  to remain at substantially the same orientation, relative to the bed portion  101 , despite any potential changed in orientation of the longitudinal axis of the cylinder  105  during cylinder  105  extension and retraction. 
     As should be appreciated by those skilled in such art, the introduction of the aforementioned second longitudinal axis  321  allows the ejector blade  104  to rotate about second longitudinal axis  321 , relative to the cylinder  105 , thereby transferring to the side wall  114 , via the yaw rollers  115 , any resultant stresses, forces and moments which otherwise would be placed on the first pivot pins  308 . 
     The resilient mounting structures  500  assist in eliminating any potential resonant rotation of the ejector blade  104  about the second longitudinal axis  321  and/or the potential tendency of the ejector blade  104  to “walk” as it is being extended/retracted along the bed portion  101 . Ejector blade-attached fasteners  501  are positioned in such manner as to pass through the apertures  508  provided in the mounting flanges  305  and to reciprocally move thereat in response to rotations of the ejector blade  104  about the second longitudinal axis  321 . Dampening of the aforementioned potential resonant effects, each mounting flange  305  in sandwiched between an upper and lower resilient member  509 , 512  each concentrically placed about the fastener  501 . Other aspects, objects and advantages of the present invention can be obtained from a study of the drawings, the disclosure and the appended claims.