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FIELD OF THE INVENTION  
         [0001]    This invention is in the field of locking mechanisms for self-dumping skid mounted containers having a catch pin.  
         BACKGROUND OF THE INVENTION  
         [0002]    Self-dumping skid mounted containers made by Roura Iron Works have been used for many years. Locking mechanisms prevent self-dumping of the containers when locked and permit self-dumping of the containers when unlocked. It is the unbalanced design of the containers which allow them to dump by virtue of their own weight. Gear-like teeth on the containers interengage apertures in the skid mounted frame which guide and restrain the container as it dumps its load. After the load has been dumped, the container rocks back into position where it is capable of being locked again. When fully loaded these containers have the capacity to hold thousands of pounds of material. If the locking mechanism is accidentally or prematurely unlocked, the container will self-dump spewing thousands of pounds of material possibly causing loss of limb or life. Such skid mounted containers are usually moved with tow motors making an accidental dump even worse as the container is then elevated several feet off the ground.  
           [0003]    Prior art locking mechanisms employ a safety latch whose design is supposed to prevent the upward motion of the handle of the locking mechanism. The safety latch of the prior art pivots about the handle of the locking mechanism and comprises a rectangular plate. To unlock the handle and permit self-dumping an operator must extend his or her arm and fingers to move the safety latch thus endangering themselves as it is possible for accidental injury to the operator&#39;s hands and/or arms if the handle does not hold the catch pin of the container in position. After the safety latch (rectangular blocking plate) has been rotated out of its blocking position, the operator must lift the handle upwardly to release the catch. Another deficiency of the prior art is that the safety latch does not always remain in the proper position due to vibration or an absent minded operator (forgetting to position the safety latch) thus raising the chance of an accident.  
           [0004]    A need therefore, exists, for a positive locking mechanism which is releasable through a single action of the operator.  
         SUMMARY OF THE INVENTION  
         [0005]    The invention is a locking mechanism for a self-dumping skid mounted container having a catch pin. When the locking mechanism is unlocked the container dumps itself. When the locking mechanism is locked the container may be filled with material. The invention is a positive locking mechanism which is releasable through a single action of the operator.  
           [0006]    A spring is operable between a pin affixed to a rotatable safety latch and the skid. The safety latch is rotatable relative to the catch pin hook. When the catch pin of the container is locked and the container is secured to the skid, the catch pin is restrained form movement by the catch pin support and locator, the catch hook and the safety latch. Unlocking of the catch pin is accomplished in a single motion of lifting the safety latch against the force of the spring and rotating it until it engages a side plate. A cam surface is formed by the top of the side plate and a flattened portion of the safety latch is the cam.  
           [0007]    As the operator continues lifting the safety latch upwardly, the cam follower of the safety latch slides along the cam and wedges against the cam. Since the safety latch is pivotally connected to the catch pin hook, the catch pin hook rotates about its pivotal connection with the side plate and the catch pin support and locator sufficiently moving the catch pin hook out of engagement with the catch pin permitting self-dumping of the container. Subsequent to the dumping of the container the catch pin of the container engages the catch pin hook causing rotation of the catch pin hook from the closed position to the open position allowing the catch pin to engage the safety latch rotating the safety latch relative to the catch pin hook against the resilient tension of the spring. The spring in combination with the weight of the safety latch and the catch pin hook urge the catch pin hook into the closed position trapping the catch pin between the safety latch, the catch pin support and locator and the catch pin hook locking the container into the locked position for the reception of material.  
           [0008]    Accordingly, it is an object of the present invention to provide a positive locking mechanism which is releasable and unlockable through a single action by the operator.  
           [0009]    It is a further object of the present invention to provide a positive locking mechanism which is unlocked by a safety latch having a cam follower which engages a cam located on a plate. The safety latch slidingly and wedgingly engages the plate and pries the catch pin hook loose from interengagement with the catch pin.  
           [0010]    It is a further object of the present invention to provide a positive latch which is coupled to the frame by a spring which assists in the rotation of the catch pin hook and the safety latch into their locked positions.  
           [0011]    It is a further object of the present invention to provide a positive locking mechanism which restrains the catch pin of a container from three places: a safety latch; a catch pin hook and a catch pin support and locator.  
           [0012]    It is a further object of the present invention to provide a positive locking mechanism which includes a safety latch and a catch pin hook with each having an open and closed position.  
           [0013]    Other objects of the invention will be understood when references is made to the Brief Description of the Drawings, the Description of the Invention and the claims which follow hereinbelow. 
       
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       [0014]    [0014]FIG. 1 is a front view of the locking mechanism of the invention illustrating the catch pin engaging the safety latch, catch pin hook and the catch pin support and locator.  
         [0015]    [0015]FIG. 2 is a rear view of the locking mechanism corresponding to the locked position illustrated in FIG. 1.  
         [0016]    [0016]FIG. 3 is a front view of the locking mechanism with the safety latch released engaging the cam on the top shelf of the plate.  
         [0017]    [0017]FIG. 4 is a rear view of the locking mechanism corresponding to the view illustrated in FIG. 3.  
         [0018]    [0018]FIG. 5 is a front view of the locking mechanism in the unlocked position illustrating the wedging action of the cam follower of the safety latch against the cam of the plate.  
         [0019]    [0019]FIG. 6 is a rear view of the locking mechanism corresponding to the view illustrated in FIG. 5.  
         [0020]    [0020]FIG. 7 is a right side view of the locking mechanism corresponding to the view in FIG. 3.  
         [0021]    [0021]FIG. 8 is a right side view of the locking mechanism corresponding to the view in FIG. 5.  
         [0022]    [0022]FIG. 9 is a perspective view of the environment of the locking mechanism illustrated together with the skid mounted self-dumping container.  
         [0023]    [0023]FIG. 10 is an enlarged front view of the safety latch.  
         [0024]    [0024]FIG. 11 is an enlarged front view of the catch pin hook.  
         [0025]    [0025]FIG. 12 is a front view of a prior art locking mechanism. 
     
    
       [0026]    A better understanding of the invention will be had when reference is made to the Description of the Invention and claims which follow herein below.  
       DESCRIPTION OF THE INVENTION  
       [0027]    [0027]FIG. 1 is a front view of the locking mechanism  100  of the instant invention illustrating the catch pin  114  engaging the safety latch  101 , catch pin hook  102  and the catch pin support and locator  104 . Side plate  103  is welded  111  to angle  106  which is shown in cross section. Rivet  115  extends through side plate  103 , catch pin hook  102  and the catch pin support and locator  104 . See, FIGS. 7 and 8. Rivet  115  is welded to catch pin support and locator  104 . See, FIG. 2 wherein the welding is indicated with reference numeral  201 . Safety latch  101  is an elongated bar pivotally connected to the catch pin hook by a rivet  116 . As shown in FIG. 1 safety latch  101  is in the closed position. The left most portion of safety latch  101  illustrates the engagement of the safety latch with the catch pin  114 . FIG. 1 also illustrates the catch pin hook  102  engaging the catch pin  114 . FIG. 3 illustrates the curvilinear surface  301  which engages the catch pin  114  when latch  101  is in the closed, locked position as shown in FIG. 1.  
         [0028]    Side plate  103  includes a cam surface  121 . Side plate  103  is rectangular plate. Safety latch  101  includes a cam follower  122  for sliding engagement with cam  121 . Catch pin  114  is mounted on plate  113  which in turn is welded to container  112 . Container  112  is illustrated in FIG. 9. FIG. 9 is a perspective view of the environment of the locking mechanism illustrated together with the skid mounted self-dumping container  112 .  
         [0029]    Referring to FIG. 1 again, spring  105  is operable between spring latch  117  and pin  107 . Pin  107  is best viewed in FIGS. 7 and 8. Pin  107  is welded to and passes through safety latch  101 .  
         [0030]    Still referring to FIG. 1 stop  109  prevents catch pin hook  102  from rotating beyond its closed position as shown in FIG. 1. Stop  109  is welded  110  to plate  103  and catch pin support and locator  104 . Catch pin hook  102  and safety latch  101  are illustrated in their closed positions in FIG. 1. Safety latch  101  pivots about rivet  116 . Rivet  116  extends through safety latch  101  and catch pin hook  102 . Rivet  116  is affixed by a weld to catch pin hook  102 .  
         [0031]    Still referring to FIG. 1, safety latch  101  has an extended portion  117  with a grip portion  118 . The grip portion enables the operator to grasp the handle and unlock the locking mechanism. Container  112  includes feet  120  resting upon frame  119 . Sometimes the frame  119  is referred to as a skid.  
         [0032]    Referring again to FIG. 9, frame  119  and one of the feet  120  are shown. Frame  119  includes apertures  901  which interengage gear-like teeth  902 . These gear-like teeth  902  reside on a curvilinear surface  903  which enables the container  112  to self-dump when the latch mechanism  100  is unlocked. Reference numeral  900  illustrates generally the environment of the positive locking mechanism.  
         [0033]    Referring again to FIG. 2 which is a rear view of the locking mechanism corresponding to the locked position illustrated in FIG. 1, reference numeral  200  generally signifies this view. Catch pin hook  102  includes a cut out  207  to allow pin  107  to rotate relative to catch pin hook  102 . Pin  107  includes a head  205  best viewed in FIGS. 7 and 8. Spring  105  is hooked over pin  107 . Catch pin hook  102  includes seat or stop  206  for the pin  107  to rest on when the safety latch  101  is in its closed or locked position and when the catch pin hook  102  is in its closed or locked position. FIG. 2 illustrates the welding  203  of the rivet  116  to the catch pin hook.  
         [0034]    Catch pin  114  is illustrated in cross section and from this view catch pin  114  is restrained by catch pin hook  102 , catch pin support and locator  104  and safety latch  101 . It is the tension of the spring  105  which urges the pin  107  against stop  206  on catch pin hook  102  thus insuring that catch pin hook  102  is not accidentally opened or unhooked. Also viewed in FIG. 2 is the upward portion  204  of the angle iron  106  not shown in FIG. 1.  
         [0035]    [0035]FIG. 3 is a front view of the locking mechanism with the safety latch  101  released and engaging the cam  121  on the top shelf of plate  103 . Reference numeral  300  generally indicates the safety latch released against the force of spring  105 . Spring  105  is slightly elongated as viewed in FIG. 3. Arrow  304  illustrates the upward movement of safety latch  101 . Safety latch  101  includes a curvilinear surface  301  which engages catch pin  114  when said safety latch is in the closed position as shown in FIG. 1. Cam follower  122  is also illustrated in FIG. 3 and reference numeral  302  is meant to illustrate the cam action between the cam  121  and cam follower  122 . Reference numeral  303  indicates the leftward position of cam follower  122  as the safety latch  101  is rotated from the closed position to the intermediate position shown in FIG. 3.  
         [0036]    [0036]FIG. 4 is a rear view of the locking mechanism corresponding to the view illustrated in FIG. 3. Reference numeral  400  generally indicates the rear view of the safety latch  101  released against the force of spring  105 . Reference numeral  401  indicates a gap between the pin  107  and seat  206  of catch pin hook  102 . Pin  107  is slightly space apart from the seat  206  of the catch pin hook  102  when the safety latch is released.  
         [0037]    [0037]FIG. 5 is a front view of the locking mechanism in the unlocked position or the open position illustrating the wedging action of the cam follower  122  of the safety latch  101  against the cam  121  of the plate  103 . Reference numeral  500  indicates the open, unlocked position of the safety latch  101  and the catch pin hook  102 . Arrow  501  indicates the upward movement of the safety latch  101  and arrow  502  indicates the upward rotational movement of container  112 . Reference numeral  503  indicates the leftward extent of the cam follower  122  with respect to the cam  121 . Reference numeral  504  is the weld of plate  113  to hopper or container  112 .  
         [0038]    Referring to FIG. 6, a rear view of the locking mechanism corresponding to the view illustrated in FIG. 5, the elongation of spring  105  can be viewed. The same approximate gap  401  between the stop  206  and the pin  107  is maintained through the rotation of the safety latch.  
         [0039]    [0039]FIG. 7 is a right side view of the locking mechanism corresponding to the view shown in FIG. 3, the beginning or intermediate stage of opening. Reference numeral  700  generally designates the right side view corresponding to FIG. 3. As viewed in FIG. 7 spring  105  is slightly elongated. It will be understood by those skilled in the art that the respective figures as illustrated in herein are not to scale but rather for illustration purposes. Scale from one drawing to the next also varies. Pin  107  is shown welded to safety latch  101  and cap or head  205  is best viewed in this drawing. Container  112  is shown at an angle with respect to frame  119  in this view and in this view while still locked pin  114  is shown parallel to frame  119 . Reference numeral  701  is used to designate the weld of the angle iron  106  to the frame  119 .  
         [0040]    [0040]FIG. 8 is a right side view of the locking mechanism corresponding the view in FIG. 5, the open position of the safety latch  101  and the catch pin hook  102 . Catch pin  114  is shown as the container  112  is rotating upward and rightwardly with respect to its initial position. Reference numeral  800  generally indicates the right side view corresponding to FIG. 5 illustrating the container raised and rotated away from its seated position.  
         [0041]    [0041]FIG. 9 is a perspective view of the environment of the locking mechanism illustrated together with the skid mounted self-dumping container. When the locking mechanism is released the container released as illustrated in FIG. 5, the container  112  rolls rightwardly and downwardly to dump its contents. Typically a towmotor&#39;s forks slidingly engage the frame  119  and raise the frame and container upwardly several feet into the air. When the container is unlocked and dumped the operator raises the grip portion  118  of the safety latch or handle  101  unlocking the mechanism and wedgingly engaging cam  121 . Cam  122  on safety latch  101  is also illustrated.  
         [0042]    [0042]FIG. 10 is an enlarged front view of the safety latch  101 . Reference numeral  1000  indicates the safety latch and handle. Aperture  1001  is for the rivet  116  and aperture  1002  is the aperture in which the pin  107  resides.  
         [0043]    [0043]FIG. 11 is an enlarged front view of the catch pin hook  102 . Reference numeral  1100  illustrates the truncated hook employed in this invention. Aperture  1101  allows for the passage of rivet  115  therethrough. Aperture  1102  allows for the passage of rivet  116  therethrough and reference numeral  1103  is the locking or engaging surface which abuts or engages catch pin  114 .  
         [0044]    [0044]FIG. 12 is a front view of a prior art locking mechanism  1200  shown with locking plate  1203  in the locked position. Handle and hook  1201  are illustrated in FIG. 12. The instant invention employs a handle comprising a safety latch  101  and a catch pin hook  102 . Locking plate  1203  pivots about a pivot pin  1202 . As shown in FIG. 12 the locking plate  1203  engages pin  114  restraining its movement. A handle  1205  is affixed to the locking plate and it is this handle  1205  which the operator must grasp to rotate plate  1203  as indicated by rotational arrow  1206 . To disengage and unlock the catch pin  114  the operator must first reach across the container  112  and handle  1205  and rotate the locking plate  1203  in a clockwise direction. He must then lift the handle  1201  and allow the escape of catch pin  114 . To lock this prior art device the operator must rotate the locking plate  1203  in a counterclockwise direction as indicated by rotational arrow  1206 . When the operator sticks his or her hand half the width of the skid to reach the locking plate  1203  it is usually in a relatively confined space which may lead to injury. The space is confined because a towmotor may be snugly up against the skid mounted container. Therefore, in the prior art device of FIG. 12 at least two steps are necessary to unlock the container and two steps are necessary to lock the container.  
         [0045]    The present invention is a positive locking mechanism. The force of the spring  105  together with the combined weight of the safety latch  101  and the catch pin hook  102  rotate the catch pin hook  102  into engagement with the stop  109 . Stop  109  is welded to plate  103  and catch pin support and locator  104 . Catch pin support and locator  104  includes a V-shaped portion which guides and locates the catch pin  114  as it enters the latching mechanism. Container  112  rotates as it dumps. As container  112  wears, the gear-like teeth do not fit as tightly within the apertures in the skid and, as such, as the container rocks back toward the locked position of the catch pin  114  will not necessarily return to the same position every time. In other words, the container  112  may wobble as it rocks back to be locked.  
         [0046]    During opening, the locking mechanism is pried to the open position as illustrated in FIG. 5. During opening the safety latch  101  is rotated counterclockwise with respect to said catch pin hook  102  and catch pin hook is rotated counterclockwise to the open, unlocked position. After the catch pin  114  is released, the handle/safety latch  101  is released and the tension in spring  104  urges the handle/safety latch  101  downwardly. Pin  107  engages shoulder  206  on catch pin hook  102  which in combination with rivet  116  urges catch pin hook  102  downwardly rotating said catch pin hook in a clockwise direction returning the locking mechanism to the position as shown in FIG. 1 only the catch pin  114  is absent therefrom.  
         [0047]    When container  112  is rotated back after having been dumped, catch pin  114  engages the sloped surface on truncated catch pin hook  102 . The weight of the container forces the catch pin hook to be rotated counterclockwise to its open position. As catch pin hook  102  rotates out of the way of catch pin  114  it is able to slip by the catch pin hook  102  and engages the top portion of safety latch  101  forcing it to rotate relative to the catch pin hook against the tension of the spring. As the catch pin  114  sufficiently engages the catch pin hook  102 , the V-shaped portion of the catch pin support and locator guides the catch pin  114  into position. The bottom of the V-shaped portion limits the travel of the catch pin in a downward direction. Spring  105  together with the weight of the hook  102  and latch  101 , lock pin  114  and securely within the grasp of the three point locking mechanism.  
         [0048]    The preferred material of the locking mechanism is carbon steel. Welding is the preferred way of attaching the rivets to one or the other of its contact points. The spring constant of the spring employed is also a function of the size and weight of the components of the invention.  
         [0049]    The invention has been described with particularity herein. Those skilled in the art will readily recognize that various changes and modifications may be made to the instant invention without departing from the spirit and scope of the appended claims.

Summary:
A locking mechanism for a self-dumping skid mounted container having a catch pin is disclosed and claimed. When the locking mechanism is unlocked the container dumps itself. When the locking mechanism is locked the container may be filled with material, usually scrap steel. A safety latch which engages the catch pin ensures that the container is not accidentally dumped. The catch pin is secured in the locked position by a catch pin hook, a pin support and locator and the safety latch. A spring is operable between the safety latch and the skid which ensures that the safety latch remains engaged. The safety latch is pivotally connected to the catch pin hook and wedgingly acts against the skid to rotate the catch pin hook out of the path of the catch pin allowing the container to self-dump.