Abstract:
A counter latch system and method of operation of a hopper having a payload and a latch moveable between a latched position and an unlatched position, the system and method including unlatching a latch of the hopper into the unlatched position and deploying a counter latch to maintain the latch in the unlatched position prior to dumping. The hopper is subsequently responsively returned into the latched position as the hopper is returned from dumping the payload.

Description:
BACKGROUND OF THE INVENTION  
         [0001]    1. Field of the Invention  
           [0002]    This invention relates to a self dumping hopper that permits safe operation of the hopper by a single operator.  
           [0003]    2. Description of Related Art  
           [0004]    Self dumping hoppers are typically used in industrial settings to hold and contain waste, finished materials, raw materials and/or other bulk materials or products that require loading and unloading through a dumping operation. As such, self dumping hoppers typically operate between a latched position, such as shown in FIG. 1, and a dumping position, such as shown in FIG. 2.  
           [0005]    The self dumping hopper is typically supported on the tines of a forklift truck which enter the fork pockets in the base in the same fashion that a pallet is handled. When unlatched, gravity maintains the hopper on a gear-like track that causes it to both dump and move forward in synchronization. When the base and track are level, an empty or uniformly loaded hopper will tend to rotate forward which causes its center of gravity to move even further forward to accelerate the dumping action. The forward tilt capability of the forklift mast may be used to move the center of gravity of an empty or loaded hopper in a forward direction; conversely, rear tilt moves the center of gravity rearward which diminishes the tendency of the hopper to dump and usually urges it into a rearward rest position against its stops.  
           [0006]    When the hopper is in its latched position it may be used for loading, storing, or transporting lading. The latched position is maintained by a latching system that is typified in FIG. 3. The latch is comprised of a hopper mounted latch pin, a frame mounted hook which is spring loaded to engage the pin, and a handle integral with the hook for manual disengagement.  
           [0007]    Normally, self-dumping hoppers are strategically located in a factory setting and simply rest with their base on a floor or ground surface. When filled, the latched self-dumping hopper is transported as a conventional forklift load. The hopper is lifted a few inches off the surface with the forklift&#39;s mast fully tilted rearward and it is then moved slowly to a container, dumpster or other receptacle. The hopper is positioned for dumping, the forklift is put into neutral with the parking brake set, and then the forks are raised sufficiently high to avoid horizontal interference with the container when the self-dumping hopper moves fully forward. Raising the trip lever handle manually from the ground, or manually from the forklift using a pole, and with the forklift mast vertical, begins the dump cycle under this one-person operation by unlatching the latch hook from the latch pin. Under uniform hopper loading, the hopper dumps automatically.  
           [0008]    Occasionally, the hopper may be heavily loaded with its center of gravity biased forward. This creates a large upward force on the hook which cannot be overcome by manually lifting the trip lever handle or pushing up on it with a pole. This upward force becomes smaller and smaller as the mast is continually tilted rearward to ease this upward force. With the upward force sufficiently eased, a oneperson dumping operation as previously described is again undertaken.  
           [0009]    Normally, in the extreme position where the mast is fully tilted inboard, the unlatching resistance is provided solely by the torsion latch spring; the loaded hopper no longer contributes to the latching resistance because its center of gravity has shifted rearward. Here, the hopper easily unlatches; however, it will relatch immediately if the trip lever handle is released. Unfortunately, the full inboard mast orientation precludes dumping by a single operator. One person cannot maintain the hopper in an unlatched state and mount the forklift and lift the mast forward to dump.  
           [0010]    The situation can be handled by a two-person dumping operation. In a two-person operation, the trip lever handle may be held in the upward or unlatched condition by a ground man while the forklift operator begins the dump cycle by tilting the mast forward.  
           [0011]    In a one-person protocol for this situation, the operator must seek an intermediate mast tilt between “rearward to release the hook” and “not too far rearward that the hook relatches.” Trial and error is used to establish an appropriate mast angle in a range where one finds “release without relatching.” 
           [0012]    To restore the hopper to its inboard latched position after dumping, several methods may be employed: (a) the mast may be tilted rearward; (b) the forklift may be backed up slightly and then stopped abruptly; (c) a pole may be used to push up on the front of the hopper; and/or (d) the forks may be lowered to the ground and the empty hopper may be lifted by hand.  
         SUMMARY OF THE INVENTION  
         [0013]    Accordingly, it is one object of this invention to provide a system for a self-dumping hopper which permits the hopper dumping to be effected as a one-person operation regardless of whether the center of gravity of the loaded fork lifted hopper is biased rearward, balanced, or biased forward when the forklift mast is tilted rearward to aid in the unlatching of the hopper to initiate its dumping.  
           [0014]    It is another object of this invention to provide a system for a self-dumping hopper that minimizes the physical exertions required to overcome the trip lever resistance encountered when unlatching the hopper to initiate dumping, by permitting the unlatching to be done with the forklift mast fully tilted rearward regardless of whether the center of gravity of the loaded fork lifted hopper is biased rearward, balanced, or biased forward.  
           [0015]    It is another object of this invention to provide a system for a self-dumping hopper that does not require that the forklift operator contact the hopper body when the hopper is elevated for dumping or when the hopper body is in motion while dumping.  
           [0016]    It is another object of this invention to provide a system for a self-dumping hopper that does not require trial and error balancing procedures to initiate dumping.  
           [0017]    It is another object of this invention to provide a system for a self-dumping hopper that does not require a pull cord for unlatching the hopper to initiate dumping, in order to achieve the objects of this invention described above.  
           [0018]    These and other objects of this invention are addressed by a counter latch system for a self-dumping hopper to be described below. A suitable system would satisfy the following qualifications: (a) it should initiate the dumping cycle at the rearmost position of mast tilt where unlatching the hopper is least strenuous; (b) it may be optionally deployed to prevent relatching at extreme rearward mast angles, or it may be ignored to leave the original system unaltered; (c) it should be located near the hopper latching system where it can be manually engaged at ground level; (d) after the system is engaged, it must automatically cause the original latching system to return to a relatching position when the hopper moves forward, thereby permitting conventional relatching after the lading is dumped.  
           [0019]    Several embodiments of a hopper mounted counter latch system invention will be disclosed, each of which fulfills all of the foregoing qualifications. The counter latch system invention embodiments are utilized when the forklift mast, fully tilted rearward, causes the center of gravity of the loaded fork lifted hopper to be biased rearward or be balanced. As previously described for this situation, to initiate dumping, the hopper latch trip lever handle must be typically raised manually and kept manually in the raised position, or else, if released, the counter torque of its return spring will relatch the hopper and prevent the dumping operation. Deploying the counter latch system obviates the necessity to manually keep the hopper trip lever handle in the raised position.  
           [0020]    All embodiments of the counter latch system of the present invention accomplish this by manually interposing a blocking member into the return path of the hopper release handle after the handle is manually moved to initiate the hopper release for dumping, thereby preventing the release handle from relatching the hopper with its hopper latching hook. The counter latch blocking member is released automatically from its deployed position and returns automatically to its undeployed position when the forward motion of the dumping hopper causes the handle to clear the deployed blocking member of the counter latch. This allows the hopper release handle with its hopper latching hook to return to its relatching mode. Thus, the operation of the counter latch system of this invention does not interfere with the hopper dumping procedure and the return of the empty hopper to its latched and locked position after dumping.  
           [0021]    A hopper with a counter latch system according to this invention is operated as follows. All loading, storing, and transporting of self-dumping hoppers proceed as normal with the hopper in a latched position and the counter latch at home base with the blocking member undeployed and flat against the hopper panel. When a filled hopper arrives at its dump site, the associated forklift has its mast fully retracted and its forks lowered. Either the forklift operator or ground personnel begin the dumping scenario by first lifting the hopper trip lever handle; minimum resistance to lifting the trip lever handle will be encountered because the mast is fully retracted. While holding the handle in one hand, the counter latch blocking member may be deployed with the other hand and the handle suitably seated against the member.  
           [0022]    The area is cleared of ground personnel and the seated forklift operator raises the hopper to the proper dumping elevation and tilts the mast of the forklift forward to begin dumping. The forward motion of the dumping hopper causes the counter latch blocking member to release the hopper latch handle. This, in turn, causes the handle with its latching hook to automatically return to its latching ready state by its return spring, and causes the blocking member to automatically return to its undeployed state by means of a spring or gravity.  
           [0023]    With the blocking member in its undeployed state, the empty hopper can now be returned and relatched to its upright position using the usual techniques. Thus, the counter latch is typically used only in the beginning of the dump cycle.  
           [0024]    The counter latch system according to one preferred embodiment of this invention is mounted on the rear panel of the hopper. According to other preferred embodiments of this invention, the counter latch system may be mounted on either the latch handle or the latch base. An objective of the counter latch system for the self dumping hopper is that the latch handle is propped up after the hopper is unlatched in the extreme rearward tilt position and the counter latch is caused to return to its original position after the hopper moves forward in its dumping motion.  
       
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       [0025]    These and other objects and features of this invention will be better understood from the following descriptions taken in conjunction with the drawings wherein:  
         [0026]    [0026]FIG. 1 is a side perspective view of a prior art hopper in a latched position;  
         [0027]    [0027]FIG. 2 is a close-up side perspective view of the prior art latch mechanism of FIG. 1 in a latched position;  
         [0028]    [0028]FIG. 3 is a side perspective view of the prior art hopper shown in FIG. 1 in a dumping position;  
         [0029]    [0029]FIG. 4 is a front perspective view of a hopper in a latched position with a counter latch system according to one preferred embodiment of this invention;  
         [0030]    [0030]FIG. 5 is a front perspective view of the hopper shown in FIG. 4 in an unlatched position and the counter latch deployed during rearward bias of the hopper;  
         [0031]    [0031]FIG. 5A is a close-up front view of a portion of the deployed counter latch system shown in FIG. 5;  
         [0032]    [0032]FIG. 6 is a front perspective view of the hopper shown in FIG. 4 in an unlatched position with the deployed counter latch system at the beginning of the hopper dump;  
         [0033]    [0033]FIG. 6A is a close-up front view of a portion of the deployed counter latch system shown in FIG. 6;  
         [0034]    [0034]FIG. 7 is a front perspective view of the hopper shown in FIG. 4 in a dumping position showing the counter latch retracted;  
         [0035]    [0035]FIG. 7A is a close-up front view of a portion of the counter latch system shown in FIG. 7;  
         [0036]    [0036]FIG. 8 is a front perspective view of a hopper in a latched position and a retracted counter latch system according to one preferred embodiment of this invention;  
         [0037]    [0037]FIG. 9 is a front perspective view of the hopper shown in FIG. 8 in an unlatched position and the counter latch deployed;  
         [0038]    [0038]FIG. 9A is a close-up front view of the deployed counter latch system shown in FIG. 9;  
         [0039]    [0039]FIG. 10 is a front perspective view of a hopper in a latched position and a retracted counter latch system according to one preferred embodiment of this invention;  
         [0040]    [0040]FIG. 11 is a front perspective view of the hopper shown in FIG. 10 in an unlatched position and the counter latch deployed;  
         [0041]    [0041]FIG. 11A is a close-up front view of the deployed counter latch system shown in FIG. 11;  
         [0042]    [0042]FIG. 12 is a front perspective view of a hopper in a latched position and a retracted counter latch system according to one preferred embodiment of this invention;  
         [0043]    [0043]FIG. 13 is a front perspective view of the hopper shown in FIG. 12 in an unlatched position and the counter latch deployed;  
         [0044]    [0044]FIG. 13A is a close-up front view of the deployed counter latch system shown in FIG. 13;  
         [0045]    [0045]FIG. 14 is a front perspective view of a hopper in a latched position and a retracted counter latch system according to one preferred embodiment of this invention;  
         [0046]    [0046]FIG. 15 is a front perspective view of the hopper shown in FIG. 14 in an unlatched position and the counter latch deployed;  
         [0047]    [0047]FIG. 15A is a close-up front view of the deployed counter latch system shown in FIG. 15;  
         [0048]    [0048]FIG. 16 is a front perspective view of a hopper in a latched position and a retracted counter latch system according to one preferred embodiment of this invention;  
         [0049]    [0049]FIG. 17 is a front perspective view of the hopper shown in FIG. 16 in an unlatched position and the counter latch deployed;  
         [0050]    [0050]FIG. 17A is a close-up front view of the deployed counter latch system shown in FIG. 17;  
         [0051]    [0051]FIG. 18 is a front perspective view of a hopper in a latched position and a retracted counter latch system according to one preferred embodiment of this invention;  
         [0052]    [0052]FIG. 19 is a front perspective view of a hopper in an unlatched position and a deployed counter latch system according to one preferred embodiment of this invention;  
         [0053]    [0053]FIG. 19A is a close-up front view of the deployed counter latch system shown in FIG. 19;  
         [0054]    [0054]FIG. 20 is a front perspective view of a hopper in a latched position with a counter latch system according to one preferred embodiment of this invention;  
         [0055]    [0055]FIG. 20A is a close-up front view of the counter latch and the latching system shown in FIG. 20;  
         [0056]    [0056]FIG. 21 is a front perspective view of the hopper shown in FIG. 20 in an unlatched position and the counter latch deployed;  
         [0057]    [0057]FIG. 21A is a close-up front view of the latching system and the deployed counter latch shown in FIG. 21 during rearward bias of the hopper;  
         [0058]    [0058]FIG. 22 is a front perspective view of the hopper shown in FIG. 20 in an unlatched position and the counter latch deployed at the beginning of the hopper dump;  
         [0059]    [0059]FIG. 22A is a close-up front view of the latching system and the counter latch shown in FIG. 22;  
         [0060]    [0060]FIG. 23 is a front perspective view of the hopper shown in FIG. 20 in a dumping position and the counter latch disengaged;  
         [0061]    [0061]FIG. 23A is a close-up front view of the latching system and the counter latch shown in FIG. 23;  
         [0062]    [0062]FIG. 24 is a front perspective view of a hopper in a latched position with a counter latch system according to one preferred embodiment of this invention;  
         [0063]    [0063]FIG. 24A is a side view of the hopper shown in FIG. 24;  
         [0064]    [0064]FIG. 25 is a front perspective view of the hopper shown in FIG. 24 in an unlatched position and the counter latch deployed during rearward bias of the hopper;  
         [0065]    [0065]FIG. 25A is a side view of the hopper and deployed counter latch shown in FIG. 25;  
         [0066]    [0066]FIG. 26 is a front perspective view of the hopper shown in FIG. 24 in an unlatched position and the counter latch deployed at the beginning of the hopper dump;  
         [0067]    [0067]FIG. 26A is a side view of the hopper shown in FIG. 26;  
         [0068]    [0068]FIG. 27 is a front perspective view of a hopper shown in FIG. 24 in a dumping position and the counter latch disengaged and retracted; and  
         [0069]    [0069]FIG. 27A is a side view of the hopper shown in FIG. 27. 
     
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS  
       [0070]    FIGS.  1 - 3  show a prior art hopper system having a standard latching system. FIGS.  4 - 7 A show a similar prior art hopper equipped with a counter latch system according to one embodiment of this invention. The hopper system includes fork pocket  21  in base  27  for access from a pair of forks from a forklift which is used to transport and elevate the hopper  20  to a container for dumping. During the loading, transport and elevation for dumping the hopper  20  is locked to the base  27  by means of its latching mechanism, which consists of the latching pin  35  mounted on the hopper body  25 , the latching hook  30  integral with its trip lever release handle  50  mounted on the hopper base pocket  21  by means of the hook and handle pivot bracket  55 , and the hook and handle return spring  65  also mounted on the pivot bracket  55 . During dumping, gravity maintains the hopper  20  on a gear-like track  22  that cooperates with trunion pins  23  in the hopper, causing the hopper to both dump and move forward in synchronization. This causes the center of gravity of the hopper  20  to move even further forward to accelerate the dumping action.  
         [0071]    With the forklift mast fully tilted rearward, and the center of gravity of the hopper  20  in this position biased rearward or balanced, the dumping process of the hopper  20  is initiated manually by a person on the ground lifting the trip lever release handle  50  to release the hopper latching hook  30  from the latching pin  35 . In the prior art hopper system, shown in FIGS.  1 - 3 , the trip lever release handle  50  must typically be kept manually in the raised position, or else, if released, the counter torque of its return spring  65  will relatch the hopper  20  and prevent the dumping operation. Equipping the prior art hopper system, FIGS.  1 - 3 , with a counter latch system according to this invention and deploying the counter latch system obviates the necessity to manually keep the hopper trip lever handle in the raised position. This permits the hopper dumping process to proceed as a one-person operation.  
         [0072]    FIGS.  4 - 7 A show a counter latch system according to one embodiment of this invention, in its various stages of operation, equipping the prior art hopper system of FIGS.  1 - 3 . FIG. 4 shows the counter latch system  40 , comprising a counter latch system bracket  37 , a pivot shaft  38  mounted in the bracket  37 , a blocking member or blocking rod  43  rigidly attached to the pivot shaft  38  and thus capable of pivoting by means of this shaft, and the rod return spring  45 , which returns the blocking rod  43  from its deployed state away from the hopper rear wall  25 , FIGS.  5 - 6 A, to its undeployed state against the hopper rear wall  25 , FIG. 4 and FIGS.  7 - 7 A.  
         [0073]    The counter latch system  40  is preferably attached to the rear hopper panel  25  by means of the counter latch system bracket  37 . The bracket  37  is strategically oriented and located on panel  25 , such that when the counter latch blocking member  43 , or rod  43 , is deployed into the return path of the raised hopper release handle  50 , FIGS.  5 - 5 A, it blocks the handle  50  from returning to its hopper latching mode. If necessary, the handle  50  may be equipped with a detent  53  as shown in the figures, in order to prevent the spring  45  to force the blocking rod  43  to prematurely release the handle  50 .  
         [0074]    As previously indicated, the dumping process of the hopper  20  is initiated manually by an operator on the ground lifting the trip lever release handle  50  to release a latch, such as the hopper latching hook  30 , from the latching pin  35 . While holding the handle  50  lifted with one hand the operator deploys the blocking rod  43  of the counter latch system under the handle  50  with the other hand to the blocking position shown in FIGS.  5 - 5 A. Now, the same operator can climb the forklift, lift the hopper system into the elevated dumping position over a dumpster and tilt the forklift mast forward to cause the hopper  20  to dump its load.  
         [0075]    As the hopper  20  in its dumping motion moves forward along its track  22 , the rear wall  25  of the hopper, together with its attached counter latch system  40  also move forward. FIGS.  5 - 7 A show that this movement will pull the blocking rod  43  of the counter latch  40  from under the handle  50 . When this happens, the handle  50  is returned by its return spring  65  to its hopper relatching position, and the blocking rod  43  of the counter latch  40  is returned by its return spring  45  to its undeployed state against the hopper rear wall  25 , FIGS.  7 - 7 A. This outcome permits the return of the empty hopper to its latched and locked position after dumping by the same process as used by prior art hoppers. Note that the release and return process of the handle  50  and the blocking rod  43  is completely automatic requiring no manual input.  
         [0076]    As described in more detail below, the counter latch system  40  of this invention may be configured and mounted to the self dumping hopper system in any number of ways. As was shown in FIGS.  4 - 7 A and will be shown in FIGS.  8 - 19 A, various embodiments of the counter latch system  40  are mounted on the hopper  20  rear panel  25 . Alternately, as shown in FIGS.  20 - 23 A, the components of an embodiment of the counter latch system  40  may be mounted on both the hopper base  27  and the hopper  20  rear panel  25 . Or, as shown in FIGS.  24 - 27 A, the components of an embodiment of the counter latch system  40  may be mounted on both the hopper  20  latch release handle  50  and the hopper  20  rear panel  25 .  
         [0077]    Additional preferred embodiments as shown in the figures are described below. Each of these embodiments require a self dumping hopper wherein latch  30  is maintained in an unlatched position by counter latch system  40  after hopper  20  is unlatched, generally in a rearward tilt position, and thereafter counter latch system  40  and latch  30  are permitted to return to their original positions after hopper  20  moves forward toward the dumping position.  
       Hopper Rear Panel-Mounted Counter Latch  
       [0078]    The counter latch system embodiment  40  shown in FIGS.  4 - 7 A belongs to this category. The counter latch system, and its operation, have been described previously in great detail.  
         [0079]    The counter latch system embodiment  40  shown in FIGS.  8 - 9 A is a variant of that shown in FIG. 4. The components and operation of the counter latch system  40  are generally the same as described for the counter latch system  40  shown in FIGS.  4 - 7 A except that the detent  53  on hopper handle  50  is no longer needed. This is achieved by changing the mounting orientation of the counter latch bracket  37  on the hopper rear panel  25 . The new mounting orientation is such that, when the counter latch blocking rod  43  is deployed under the handle  50  into the blocking position as shown in FIGS.  9 - 9 A, a premature release of the handle  50  cannot occur. This eliminates the need of a detent  53  on handle  50  which was present in the counter latch system  40  shown in FIGS.  4 - 7 A. Therefore, there is no such detent shown in FIGS.  8 - 9 A. FIG. 8 shows the counter latch  40  in its undeployed state with the hopper  20  latched and locked prior to dumping. FIGS.  9 - 9 A show the hopper  20  unlatched in readiness for dumping, with the counter latch  40  in its deployed blocking state under the hopper latch release handle  50 , to prevent the handle from relatching the hopper  20  before dumping.  
         [0080]    The counter latch system embodiment  40  shown in FIGS.  10 - 11 A is a variant of that shown in FIG. 4 and FIG. 8. Here, the rod return spring  45  has been eliminated in addition to the detent  53  on handle  50 . All other components and operation of this new embodiment are the same as described for the counter latch system  40  shown FIGS.  4 - 7 A. The difference as compared with FIG. 8, is a change in the mounting orientation of the counter latch bracket  37  on the hopper rear panel  25 . The new mounting orientation shown in FIG. 10 is such that, when the counter latch blocking rod  43  returns from its deployed state under the raised handle  50 , FIGS.  11 - 11 A, to its undeployed state against the hopper panel  25 , FIG. 10, it does so by the force of gravity acting on the blocking rod  43  when the hopper dumping motion pulls the blocking rod  43  from under the handle  50 . This eliminates the need for a counter latch rod return spring  45  present in the counter latch system  40  shown in FIGS.  8 - 9 A. Therefore, there is no such spring shown in FIGS.  10 - 11 A. FIG. 10 shows the counter latch  40  in its undeployed state with the hopper  20  latched and locked prior to dumping. FIGS.  11 - 11 A show the hopper  20  unlatched in readiness for dumping, with the counter latch  40  in its deployed blocking state under the hopper latch release handle  50 , to prevent the handle from relatching the hopper  20  before dumping.  
         [0081]    The counter latch system embodiment  40  shown in FIGS.  12 - 13 A is a variant of that shown in FIG. 4 and FIG. 10. Here, the pivot shaft  38  of the rod  43  is mounted in the bracket  37  in an angled orientation relative to the surface of the hopper rear panel  25 , whereas in FIG. 10 the pivot shaft  38  was parallel to the surface of the hopper rear panel  25 . In this new orientation, the lower end of the shaft  38  is farther away from the panel  25  surface than the upper end of the shaft. All other components and operation of this new embodiment are generally the same as described for the counter latch system  40  shown FIGS.  4 - 7 A. This change in the pivot shaft  38  orientation increases the gravitational return force acting on the counter latch blocking rod  43  as compared with that of the counter latch system embodiment  40  shown in FIGS.  10 - 11 A. FIG. 12 shows the counter latch  40  in its undeployed state with the hopper  20  latched and locked prior to dumping. FIGS.  13 - 13 A show the hopper  20  unlatched in readiness for dumping, with the counter latch  40  in its deployed blocking state under the hopper latch release handle  50 , to prevent the handle from relatching the hopper  20  before dumping.  
         [0082]    The counter latch system embodiment  40  shown in FIGS.  14 - 15 A is a variant of that shown in FIG. 4 and FIG. 12. Here, the angled orientation of the pivot shaft  38  of the rod  43  relative to the surface of the hopper rear panel  25  is achieved by angling the mounting surface of bracket  37  in contact with the rear panel  25  as shown in FIGS.  14 - 15 A. All other components and operation of this new embodiment are generally the same as for the counter latch system  40  shown FIGS.  12 - 13 A. FIG. 14 shows the counter latch  40  in its undeployed state with the hopper  20  latched and locked prior to dumping. FIGS.  15 - 15 A show the hopper  20  unlatched in readiness for dumping, with the counter latch  40  in its deployed blocking state under the hopper latch release handle  50 , to prevent the handle from relatching the hopper  20  before dumping.  
         [0083]    The counter latch system embodiment shown in FIGS.  16 - 17 A is a variant of that of FIG. 10, the springless detentless counter latch system. Here, the whole counter latch system  40  of FIG. 10 has been replaced with a counter latch system  90  consisting of a commercial hinge, which likely costs less than fabricating a counter latch system such as  40 . The operation of the counter latch system embodiment  90  is the same as for the counter latch system  40  shown in FIGS.  10 - 11 A. FIG. 16 shows the counter latch  90  in its undeployed state with the hopper  20  latched and locked prior to dumping. FIGS.  17 - 17 A show the hopper  20  unlatched in readiness for dumping, with the counter latch  90  in its deployed blocking state under the hopper latch release handle  50 , to prevent the handle from relatching the hopper  20  before dumping.  
         [0084]    The counter latch system  90  of FIGS.  16 - 17 A is typically attached to the rear hopper panel  25  by means of the hinge leaf  82  using screws through the existing holes in leaf  82 . The leaf  82  is attached to panel  25  with the hinge pin hoops  81  in contact with, and laying flat against, the surface of the panel  25 . This mode of attachment permits the counter latch blocking member, the hinge leaf  85 , to open only about 90 degrees away from the panel  25  when deployed as the blocking member under the hopper handle  50 . This obviates the need of having a detent on handle  50  to prevent the hinge leaf  85  from releasing the handle  50  by opening too much. The attachment orientation of leaf  82  on panel  25  is selected so as to cause the counter latch blocking member, the hinge leaf  85 , to return from its deployed state under the raised handle  50 , FIGS.  17 - 17 A, to its undeployed state against the hopper panel  25 , FIG. 16, by the force of gravity acting on the leaf  85  when the hopper dumping motion pulls the blocking leaf  85  from under the handle  50 .  
         [0085]    The counter latch system embodiment  90  shown in FIGS.  18 - 19 A is a variant of that of FIG. 16. It has an enhanced gravitational return force acting on the counter latch blocking member  85 . To achieve the enhancement, the hinge leaf  82  has been attached to the rear hopper panel  25  such that lower end of the hinge pin hoops  81  seen in the figures is raised away from the rear hopper panel  25  while the upper end of the hinge pin hoops  81  is not. This change of the hinge pin hoops  81  orientation increases the gravitational return force acting on the counter latch blocking member, hinge leaf  85 , as compared with that of the counter latch system embodiment  90  shown in FIGS.  16 - 17 A. The operation of this new counter latch system embodiment is the same as for the counter latch system  90  shown in FIGS.  16 - 17 A. FIG. 18 shows the counter latch  90  in its undeployed state with the hopper  20  latched and locked prior to dumping. FIGS.  19 - 19 A show the hopper  20  unlatched in readiness for dumping, with the counter latch  90  in its deployed blocking state under the hopper latch release handle  50 , to prevent the handle from relatching the hopper  20  before dumping.  
       Hopper Base-Mounted Counter Latch  
       [0086]    FIGS.  20 - 23 A show a hopper base mounted counter latch system, according to one embodiment of this invention, in its various stages of operation. The counter latch system  40 , consists of the counter latch system bracket  71  mounted on the hopper base  27  as shown, a pivot shaft  72  mounted pivotally in the bracket  71 , the counter latch blocking prop  70 , preferably saddle shaped as shown, rigidly attached to the pivot shaft  72 , the blocking prop return spring  73 , which returns the prop  70  from its deployed state under the hopper release handle  50 , to its undeployed state against the hopper base  27 , and the blocking prop release link  80  mounted pivotally on the hopper rear panel  25 .  
         [0087]    [0087]FIG. 20, and its closeup view FIG. 20A, show the latched hopper prior to its dumping initiation mounted on a forklift (not shown) with the forklift mast fully tilted rearward. As previously described, the dumping process of the hopper  20  is initiated manually by an operator on the ground lifting the trip lever release handle  50  to release the latch, specifically a hopper latching hook  30 , from the latching pin  35 . While holding the handle  50  lifted with one hand, the operator deploys the counter latch blocking prop  70  through the prop release link  80  and under the handle  50  with the other hand, to the blocking position shown in FIGS.  21 - 21 A. The same operator can now climb the forklift, lift the hopper system into the elevated dumping position over a dumpster and tilt the forklift mast forward to cause the hopper  20  to dump its load.  
         [0088]    As the hopper  20  in its dumping motion moves forward along its track  22 , the rear panel  25  of the hopper, together with its attached blocking prop release link  80  also move forward. FIGS.  22 - 22 A show that this movement of the blocking prop release link  80  will pull the blocking prop  70  from under the handle  50 . When this happens, the handle  50  is returned by its return spring  65  to its hopper relatching position, and the blocking prop  70  of the counter latch  40  is returned by its return spring  73  to its undeployed state against the hopper base  27  as shown in FIGS.  23 - 23 A. This outcome permits the return of the empty hopper to its latched and locked position after dumping by the same process as used by prior art hoppers. Note that the release and return process of handle  50  and the blocking prop  70  is completely automatic requiring no manual input.  
       Hopper Latch Handle-Mounted Counter Latch  
       [0089]    FIGS.  24 - 27 A show a hopper latch handle mounted counter latch system, according to one embodiment of this invention, in its various stages of operation. The counter latch system  40  preferably comprises the counter latch blocking prop  70  pivotally mounted on the hopper latch handle  50  toward the top of this handle as shown, the blocking prop stop  77 , the blocking prop return spring  45 , which returns the prop  70  from its deployed state shown in FIGS.  25 - 25 A and FIGS.  26 - 26 A, to its undeployed state against the hopper latch handle  50  shown in FIGS.  27 - 27 A, and the blocking prop cradle  75  mounted on the hopper rear panel  25 .  
         [0090]    [0090]FIG. 24, and its closeup view FIG. 24A, show the latched hopper prior to to its dumping initiation mounted on a forklift (not shown) with the forklift mast fully tilted rearward. The dumping process of the hopper  20 , is initiated manually by an operator on the ground pulling the trip lever release handle  50  away from the hopper rear panel  25  to release a latch, such as the hopper latching hook  30 , from the latching pin  35 . While holding the handle  50  back with one hand, the operator deploys the counter latch blocking prop  70  onto the blocking prop cradle  75  with the other hand, to the latch handle  50  blocking position shown in FIGS.  25 - 25 A. The same operator can now climb the forklift, lift the hopper system into the elevated dumping position over a dumpster and tilt the forklift mast forward to cause the hopper  20  to dump its load.  
         [0091]    As the hopper  20  in its dumping motion moves forward along its track  22 , the rear panel  25  of the hopper, together with its attached blocking prop cradle  75  also move forward. FIGS.  26 - 26 A show that this movement of the blocking prop cradle  75  will pull the blocking prop  70  away from blocking prop cradle  75 . When this happens, the handle  50  is returned by its return spring  65  to its hopper relatching position against its stop  78 , and the blocking prop  70  of the counter latch  40  is returned by its return spring  45  to its undeployed state against its blocking prop stop  77  on the hopper latch handle  50  as shown in FIGS.  27 - 27 A. This outcome permits the return of the empty hopper to its latched and locked position after dumping by the same process as used by prior art hoppers. Note that the release and return process of handle  50  and the blocking prop  70  is completely automatic requiring no manual input.  
         [0092]    While in the foregoing specification this invention has been described in relation to certain preferred embodiments thereof, and many details have been set forth for purpose of illustration, it will be apparent to those skilled in the art that the invention is susceptible to additional embodiments and that certain of the details described herein can be varied considerably without departing from the basic principles of the invention.