Abstract:
A device and method which implements a preferred embodiment of the present invention includes a means for controlling the door of a shovel bucket. In one embodiment, an adjustable connecting rod may be configured to pivotally connect to a shovel bucket. A fixed connecting rod may be configured to pivotally connect to the adjustable connecting rod and pivotally connect to the door of the shovel bucket. The proximal end of the adjustable connecting rod may move in a direction towards the shovel bucket when the door is closing in order to lock the door. An eccentric assembly may be configured to move the proximal end of the adjustable connecting rod in a direction away from the shovel bucket after the door has closed in order to unlock the door.

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
       [0001]    This non-provisional application claims priority based upon prior U.S. Provisional Patent Application Ser. No. 61/370,256 filed Aug. 3, 2010 in the name of Alberto Opazo, entitled “Control Device for Shovel-Bucket Door,” the disclosure of which is incorporated herein by reference. 
     
    
     BACKGROUND OF THE INVENTION 
       [0002]    The present invention relates generally to shovel buckets and, more particularly, to the control of shovel-bucket doors. 
         [0003]    Shovel and loading equipment buckets (collectively, “shovel buckets”) are frequently used in the construction and mining industries in aggressive mining or earth movement operations. Shovel buckets often have a cover or door that is hinged to the shovel bucket. Shovel buckets also traditionally include a cable and latch system to open and close the door. Tension in the cable can be mechanically or electro-mechanically managed to remotely open and close the door. For example, the latch may keep the door locked in a closed position until the cable is used to open the latch and allow the door to swing open. When the door swings closed, the cable can also be used to close the latch so that the door is locked in a closed position. 
         [0004]    Shovel buckets have cycle times between load dumping that may vary depending on factors such as the swing angle of the shovel bucket as it scoops up load material and swings to a location where it will unload the load material, the weight of the load material in the shovel bucket, and operator skill. The longest percentage of time in the cycle is swinging time. 
         [0005]    Even with the use of cable and latch systems, shovel-bucket doors are frequently exposed to intense banging and slamming due, in part, to the weight of the door. Such intense banging and slamming can increase wear and lead to premature failure of a shovel bucket, its door, and its other components. For example, the door may become misaligned with the shovel bucket and wear plates on the shovel bucket or door may be damaged or cracked, each requiring service or readjustment and costly equipment downtime. Likewise, the cable may suffer damage from the intense banging and slamming of the door and, as a result, may need to be serviced or replaced. 
         [0006]    Consequently, there is a significant need for a device and method that will improve shovel-bucket door performance, reduce shovel bucket down time, and reduce the impact and blows of the door against the shovel bucket. There is also a significant need for a device and method that will provide a mechanical advantage for the input force needed to open and close the door in view of the weight of the material in the shovel bucket and the inertial effects of the door. There is also a significant need for a device and method that will yield minimal output torque and dampen loads due to the inertial effects of the door opening and closing. The present invention provides these and other advantages, as will be apparent from the following detailed description and accompanying figures. 
       SUMMARY OF THE INVENTION 
       [0007]    A device and method which implements a preferred embodiment of the present invention includes a means for controlling the door of a shovel bucket. In one embodiment, an adjustable connecting rod may be configured to connect to a shovel bucket and a fixed connecting rod may be configured to connect to the adjustable connecting rod and the door of the shovel bucket. The angle between the fixed connecting rod and the distance between the pivot point of the distal end of the fixed connecting rod and the pivot point of the distal end of the adjustable connecting rod may be greater than zero when said door is closed. 
         [0008]    In one embodiment, an adjustable connecting rod may be configured to pivotally connect to a shovel bucket. A fixed connecting rod may be configured to pivotally connect to the adjustable connecting rod and pivotally connect to the door of the shovel bucket. The proximal end of the adjustable connecting rod may move in a direction towards the shovel bucket when the door is closing. An eccentric assembly may be configured to move the proximal end of the adjustable connecting rod in a direction away from the shovel bucket after the door has closed. 
         [0009]    In one embodiment, the door of a shovel bucket may be controlled by first positioning the shovel bucket such that gravity will allow the door to swing to a closed position and the proximal end of a fixed connecting rod will rest against an eccentric base support. The proximal end of an adjustable connecting rod may then be moved a predetermined distance away from said shovel bucket after said door is in a closed position. The proximal end of the adjustable connecting rod may be pivotally connected to the proximal end of the fixed connecting rod, the distal end of the adjustable connecting rod may be pivotally connected to the shovel bucket, and the distal end of the fixed connecting rod may be pivotally connected to the door. The shovel bucket may then be positioned such that gravity will allow said door to swing open. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0010]    Before drawings are presented it is to be understood that the invention is not limited to the details of the assembly and arrangements of the components set forth in the following description or illustrated in the drawings. The invention is capable of its major components being carried out and assembled in various ways. For a more complete understanding of the present invention, and the advantages thereof, reference is now made to the following descriptions, taken in conjunction with the accompanying drawings but not limited to represent the whole invention, in which: 
           [0011]      FIG. 1  shows an isometric view of a shovel bucket that includes one embodiment of the present invention. 
           [0012]      FIG. 2  shows a side view of a shovel bucket that includes one embodiment of the present invention. 
           [0013]      FIG. 3  shows an isometric view of a shovel bucket that includes one embodiment of the present invention with one fixed connecting rod removed. 
           [0014]      FIG. 4  shows a detailed view of the proximal end of an adjustable connecting rod suspended just above an eccentric base support in one embodiment of the present invention. 
           [0015]      FIG. 5  shows an isometric view of an eccentric assembly in one embodiment of the present invention. 
           [0016]      FIG. 6  shows an isometric view of an adjustable connecting rod in one embodiment of the present invention. 
           [0017]      FIG. 7  shows an isometric view of an eccentric base support in one embodiment of the present invention. 
           [0018]      FIG. 8  shows an isometric view of a door mount assembly in one embodiment of the present invention. 
           [0019]      FIG. 9  shows a side view of one embodiment of the present invention and a shovel bucket with a door in a closed position. 
           [0020]      FIG. 10  shows a side view of one embodiment of the present invention and a shovel bucket with a door in a slightly open position. 
           [0021]      FIG. 11  shows a side view of one embodiment of the present invention and a shovel bucket with a door in an open position. 
           [0022]      FIG. 12  shows a side view of one embodiment of the present invention and a shovel bucket with a door in a fully open position. 
       
    
    
     DETAILED DESCRIPTION 
       [0023]    Reference is now made to  FIG. 1  which shows an isometric view of a shovel bucket  100  in one embodiment of the present invention. In this embodiment, the shovel bucket  100  includes a door  102  on the posterior  100   d  of the shovel bucket  100  and an opening (not shown) on the anterior  100   e  of the shovel bucket  100 . The shovel bucket  100  also includes for purposes of illustration, a top side  100   a , a right side  100   b , and a left side  100   c . The proximal end of the door  102  is shown to be pivotally connected to two door mount assemblies  103 . Each of the two door mount assemblies  103  may be configured to connect to the door  102 , the shovel  100 , and a fixed connecting rod  101 . One door mount assembly  103  may be connected to the shovel  100  on the top side  100   a  of the shovel  100  generally near the right-posterior corner of the top side  100   a  and one door mount assembly  103  may be connected to the shovel  100  on the top side  100   a  of the shovel  100  generally near the left-posterior of the top side  100   a . The shovel bucket  100  may include a mount  109  that may be configured to connect to the door mount assembly  103 . 
         [0024]    The distal end  101   a  of each of the fixed connecting rods  101  is shown to be pivotally connected to one of the door mount assemblies  103  and the proximal end  101   b  of each of the fixed connecting rods  101  is shown to be pivotally connected to the proximal end  105   b  of an adjustable connecting rod  105 . The proximal end  101   b  of each of the fixed connecting rods  101  is also shown to be positioned above an eccentric base support  107 . One eccentric base support  107  may be connected to the top side  100   a  of the shovel  100 , in a position generally flush with or slightly offset from the right side  100   b  of the shovel  100  and one eccentric base support  107  may be connected to the top side  100   a  of the shovel  100 , in a position generally flush with or slightly offset from the left side  100   c  of the shovel  100 . The proximal end  105   b  of the adjustable connecting rod  105  is also shown to be positioned above the eccentric base support  107 . 
         [0025]    The distal end  105   a  of each of the adjustable connecting rods  105  may pivotally connect to a fixed shovel support  106  which may be part of the shovel bucket  100  or an addition connected to the shovel bucket  100 . One fixed shovel support  106  may be connected to the top side  100   a  of the shovel  100 , in a position generally flush with or slightly offset from the right side  100   b  and near the anterior  100   e  of the shovel  100  and one fixed shovel support  106  may be connected to the top side  100   a  of the shovel  100 , in a position generally flush with or slightly offset from the left side  100   c  and near the anterior  100   e  of the shovel  100 . 
         [0026]    An eccentric assembly  104  is shown to connect to each of the eccentric base supports  107 . The length of the eccentric assembly is generally parallel to the posterior  100   d  and anterior  100   e  of the shovel bucket  100  and generally perpendicular to the right side  100   b  and left side  100   c  of the shovel bucket  100 . The eccentric assembly  104  may also include a moment arm  108 . In this embodiment, the moment arm  108  is comprised of two moment aim plates  108   a  and  108   b . As will be described in more detail below, movement of the moment arm  108  in a clockwise direction may cause the eccentric assembly  104  to apply an upward force on the proximal ends  105   b  of the adjustable connecting rods  105  and, thereby, cause the proximal ends  105   b  of the adjustable connecting rods  105  and the proximal ends  101   b  of the fixed connecting rods  101  to move upward so that the door  102  may open from a closed position. 
         [0027]    Reference is now made to  FIG. 2  which shows a side view of a shovel bucket  100  that includes one embodiment of the present invention. In this embodiment, the door  102  is in a closed position and rests against the posterior  100   d  of the shovel bucket  100 . The door mount assembly  103  is connected to the proximal end  102   a  of the door  102 , the shovel bucket  100 , and the distal end  101   a  of a fixed connecting rod  101 . The proximal end  101   b  of the fixed connecting rod  101  is shown to be pivotally connected to the proximal end  105   b  of an adjustable connecting rod  105 . The distal end  105   a  of the adjustable connecting rod  105  is shown to be pivotally connected to the fixed shovel support  106 . The proximal end  101   b  of the fixed connecting rod  101  may rest on an eccentric base support  107  when the door  102  is in a closed position. An eccentric end cap on one end of the eccentric assembly  104  is shown to connect to the eccentric base support  107 . 
         [0028]    In one embodiment, the door  102 , the fixed connecting rod  101 , and the adjustable connecting rod  105  can be viewed as a mechanism that can be adjusted to lock the door  102  and prevent undesired locking and jamming of the door  102 . For purposes of illustration, the distance  204  between the pivot point  201  of the distal end  101   a  of the fixed connecting rod  101  and the pivot point  202  of the proximal end  101   b  of the fixed connecting rod  101 , the distance  205  between the pivot point  202  of the proximal end  101   b  of the fixed connecting rod  101  and the pivot point  203  of the distal end  105   a  of the adjustable connecting rod  105 , and the distance  206  between the pivot point  201  and the pivot point  203  can comprise a triangle  207 . In one embodiment, the lock angle θ that is formed by the intersection of distance  204  and distance  206  of the triangle  207  is greater than zero but less than or equal to 1.5 degrees when the door  102  is closed. In one embodiment, the lock angle θ is approximately equal to 1.5 degrees when the door  102  is closed. In one embodiment, the magnitude of the lock angle θ when the door is closed can be adjusted by the adjusting height of the eccentric base support  107  and/or the length of the adjustable connecting rod  105 . In one embodiment, the distance  206  is approximately 2,146 millimeters when the door  102  is closed. In one embodiment, the distance  205  may be adjusted to a value between 813 millimeters and 850 millimeters. Stated differently, in one embodiment, the length of each adjustable connecting rod  105  may be adjusted within a variance of approximately 37 millimeters. In one embodiment, the distance  205  may be varied by adjusting the length of the adjustable connecting rods  105 . In one embodiment, when the door  102  is closed, the shortest distance  208  between point  202  and the distance  206  is equal to a value between approximately 10 millimeters and approximately 20 millimeters. 
         [0029]    Reference is now made to  FIG. 3  which shows an isometric view of a shovel bucket  100  that includes one embodiment of the present invention with one fixed connecting rod  105  removed. In this embodiment, the fixed connecting rod  101  on the right side of the shovel bucket  105  has been removed. As a result, the proximal end  105   b  of the adjustable connecting rod  105  is visible suspended just above the eccentric base plate  107 . The portion of the proximal end  105   b  of the adjustable connecting rod  105  encircled by circle  303  is shown in more detail in  FIG. 4 . 
         [0030]    Reference is now made to  FIG. 4  which shows a detailed view of the proximal end  105   b  of an adjustable connecting rod  105  suspended just above an eccentric base support  107  in one embodiment of the present invention. In this embodiment, the adjustable connecting rod  105  is shown to have a wear plate  403  along the bottom of outside surface of the proximal end  105   b  of the adjustable connecting rod  105 . When the door  102  (not shown) is in a closed position, the proximal end  101   b  of the fixed connecting rod  101  may rest against the stops  404  of the eccentric base support  107 . In other embodiments, when the door  102  is in a closed position, the proximal end  105   b  of the adjustable connecting rod  105  may rest against the stops  404  of the eccentric base support  107 . To open the door, the eccentric guide  406  may rotate upward so that the eccentric roll-wear plate  405  applies an upward force  407  on the wear plate  403  and pushes the proximal end  105   b  of the adjustable connecting rod  105  upward. In one embodiment, the wear plate  403  may be made of material that is more resistant to wear and damage than the material comprising the rest of the adjustable connecting rod  105 . In addition, by limiting contact of the eccentric roll-wear plate  405  to the wear plate  403  of the adjustable connecting rod  105  (as opposed to the body of the proximal end  105   b  of the adjustable connecting rod  105 ), wear and damage resulting from repeated contact with the eccentric roll-wear plate  405  will generally be limited to wear plate  403 . As a result, an operator may be able to change out a worn wear plate  403  rather than removing an entire adjustable connecting rod  105 . 
         [0031]    In one embodiment, the adjustable connecting rod  105  includes a second wear plate  402  on the top side of the outer surface of the proximal end  105   b  of the adjustable connecting rod  105 . As a result, when the wear plate  403  is worn, an operator may simply rotate the proximal end  105   b  of the adjustable connecting rod  105  (or, alternatively, rotate the entire adjustable connecting rod  105 ) one hundred eighty degrees so that the eccentric roll-wear plate  405  will contact wear plate  402  in order to open the door  102  from a closed position. In one embodiment, the proximal end  105   b  of the adjustable connecting rod  105  may include a lubrication port  401 . 
         [0032]    Reference is now made to  FIG. 5  which shows an isometric view of an eccentric assembly  104  in one embodiment of the present invention. In this embodiment, the eccentric assembly includes a main tube  505  with an eccentric end cap  209  at each end of the main tube  505 . The eccentric assembly  104  may also include an eccentric guide  406  located near each end of the main tube  505 . In this embodiment, each of eccentric guide  406  is positioned equidistant from the center of the main tube  505  and the angular position of each eccentric guide  406  about the main tube  505  is approximately equivalent. Each eccentric guide  406  may include two eccentric guide plates  501  and an eccentric roll-wear plate  405 . In this embodiment, the proximal ends  501   b  of the eccentric guide plates  501  may slide onto, and be securely fastened to, the main tube  505 . The distal ends  501   a  of the eccentric guide plates  501  may connect to the eccentric roll-wear plate  405 . In this embodiment, the eccentric roll-wear plate  405  is wheel-shaped and is configured to connect between the distal ends  501   a  of two eccentric guide plates  501 . 
         [0033]    The eccentric assembly  104  may also include a moment arm  108 . In this embodiment, the moment arm  108  includes the moment arm plates  108   a  and  108   b  which are connected by moment rod  506 . In this embodiment, the angular position of the moment arm  108  about the main tube  505  relative to the angular position of the eccentric guides  406  about the main tube  505  is adjusted so that when a force is applied to the moment arm  108  that causes the main tube  505  to rotate in a clockwise direction the eccentric guides  406  will also rotate clockwise and the eccentric roll-wear plates  405  will apply an upward force  407  on the wear plate  403  of the adjustable connecting rod  105 . It can be appreciated that other embodiments of the present invention may include other mechanisms for rotating the eccentric assembly  104  and/or the eccentric guides  406  without departing from the spirit and scope of the invention. 
         [0034]    Reference is now made to  FIG. 6  which shows an isometric view of an adjustable connecting rod  105  in one embodiment of the present invention. In this embodiment, the proximal end  105   b  and the distal end  105   a  of the adjustable connecting rod  105  are identical in shape so that either of the two ends of the adjustable connecting rod  105  may be used to connect to the proximal end  101   b  of the fixed connecting rod  101  and either of the two ends of the adjustable connecting rod  105  may be used to connect to the fixed shovel support  106 . For example, the adjustable connecting rod  105  may include wear plates  403  on its proximal end  105   b  and its distal end  105   a  so that the direction of the adjustable connecting rod  105  is interchangeable. 
         [0035]    In one embodiment, the distal end  105   a  of the adjustable connecting rod  105  may contain one of either right hand or left hand threads that may be screwed into the nut adjustable  604  and the proximal end  105   b  of the adjustable connecting rod  604  may contain the other of either right hand or left hand threads that may be screwed into the nut adjustable  604 . The length of the adjustable connecting rod  105  may be varied by screwing in or screwing out the distal end  105   a  and/or the proximal end  105   b  of the adjustable connecting rod until the adjustable connecting rod  105  is at a desired length. Once the adjustable connecting rod  105  is at a desired length, the lock pins  601  may be secured into a receptacle  605  of the locking-pin assembly  602 . In this embodiment, a locking-pin assembly  602  is configured to fasten around the diameter of each end of the nut adjustable  604 . 
         [0036]    The proximal end  105   b  of the adjustable connecting rod  105  is shown to include a lubrication port  401 . The lubrication port  401  may be used to lubricate the rod end bushing  603  to assist movement of the proximal end  101   b  of the adjustable connecting rod  105  and the proximal end  105   b  of the adjustable connecting rod  105 . Although not shown in  FIG. 6 , the distal end  105   a  of the adjustable connecting rod  105  may also include a lubrication port  401 . 
         [0037]    Reference is now made to  FIG. 7  which shows an isometric view of an eccentric base support  107  in one embodiment of the present invention. The eccentric base support  107  may include a base plate  702 , an external lateral support  701 , an eccentric internal support  703 , steel liners  705 , rubber liners  706 , and stops  404 . The external lateral support  701  and eccentric internal support  703  may extend from or be mounted to the base plate  702 . In one embodiment, the external lateral support  701  and the eccentric internal support  703  are positioned perpendicular to the base plate  702  and parallel to each other. In one embodiment, the distance between the external lateral support  701  and the eccentric internal support  703  is proportional to the width of the proximal end  105   b  of the adjustable connecting rod  105 . The external lateral support  701  and the eccentric internal support  703  may also be aligned such that the aperture  708  in the external lateral support  701  aligns with the tube slot  707  in the eccentric internal support  703 . In this configuration, the main tube  505  of the eccentric assembly  104  may extend through the aperture  708  such that the eccentric end cap  209  may connect to end of the main tube  505  on the external side  709  of the external lateral support  701 . The main tube  505  may also pass through and/or be supported by the tube slot  707 . The eccentric guides  406  may be positioned along the main tube  505  between the external lateral support  701  and the eccentric internal support  703 . 
         [0038]    In one embodiment, a stop  404   a  may be attached to the guide  704   a  at the top of the external lateral support  701  and a stop  404   b  may be attached to the guide  704   b  at the top of the eccentric internal support  703 . In one embodiment, the stops  404  may have concave surfaces that fit the shape of the proximal end  101  b of the fixed connecting rod  101  or the proximal end  105   b  of the adjustable connecting rod  105 . In one embodiment, steel liners  705  and rubber liners  706  may be positioned between the stops  404  and the guides  705 . In one embodiment, a single steel liner  705  may underlie a single rubber liner  706 . In this configuration, for example, the steel liner  705  may structurally support the rubber liner  706  and provide structural support for fastening the stop  404 , the steel liner  705 , and the rubber liner  706  to the guide  704 . In addition, the rubber liner  706  may absorb the impact of, and dampen the movement of, the proximal end  105   a  of the adjustable connecting rod  105  when it strikes the stop  404 . In one embodiment, the stop  404 , the steel liner  705 , and the rubber liner  706  may be bolted to the guide  704 . However, it can be appreciated that other embodiments of the present invention may include other mechanisms for fastening the stop  404 , the steel liner  705 , and the rubber liner  706  to the guide  704  without departing from the spirit and scope of the invention. 
         [0039]    Reference is now made to  FIG. 8  which shows an isometric view of a door mount assembly  103  in one embodiment of the present invention. The door mount assembly may include a top mounting washer  802 , an external wing support  803 , and internal wing support  801 , an external wing support  806 , a wing base support  804 , and a lower mounting washer  805 . In one embodiment, the shape of the wing base support  804  may be curved. For example, the shape of the wing base support  804  may be curved to reduce the risk of the formation of large stress concentration fractures under high loads, such as those created by movement of the door  102 . The wing base support  804  may also include the lower mounting washer  805 . The lower mounting washer  805  may be configured to connect to the distal end  101   a  of the fixed connecting rod  101 . 
         [0040]    The internal wing support  801  and the external wing support  806  may be configured to connect to the proximal end  102   a  of the door  102  such that the external wing support  806  connects to the outer surface (the surface facing away from the shovel bucket) of the door  102  and the internal wing support  801  connects to the inner surface (the surface facing the shovel bucket) of the door  102 . The top mounting washer  802  may connect to the shovel bucket at the mount  109 . In one embodiment, the external wing support  806  may curve  803  and extend to or near the top mounting washer  802  to improve the structural strength of the door mount assembly  103  when mounted to the door  102 . For example, the curve  803  of the external wing support  806  may provided additional welding area for connecting the proximal end  102   a  of the door  102  to the door mount assembly  103 . 
         [0041]    Reference is now made to  FIG. 9  which shows a side view of one embodiment of the present invention and a shovel bucket  100  with a door  102  in a closed position. In this embodiment, the lock angle θ is greater than zero and the fixed connecting rod  101  and the adjustable connecting rod  105  prevent the door from opening. In this configuration the shovel bucket  100  is in a digging state. 
         [0042]    Reference is now made to  FIG. 10  which shows a side view of one embodiment of the present invention and a shovel bucket  100  with a door  102  in a slightly open position. In this embodiment, the eccentric roll wear plate  405  has applied an upward force on the wear plate  403  of proximal end  105   b  of the adjustable connecting rod  105 . As a result, the proximal end  105   b  of the adjustable connecting rod  105  and the proximal end  101   b  of the fixed connecting rod  101  has moved upwards (or away from the shovel bucket  100 ). As a result, the pivot point  201  of the distal end  101   a  of the fixed connecting rod  101  has moved slightly closer to the pivot point  203  of the distal end  105   a  of the adjustable connecting rod  105  and the door  102  has slightly opened. In addition, the lock angle θ is now slightly negative because the pivot point  202  at the proximal end  101   b  of the fixed connecting rod  101  has moved above the distance between pivot point  201  and pivot point  203 . With pivot point  202  in this position, the door  102  would swing open if the shovel bucket  100  were to move to cause the door  102  to open, such as by rotating counter clockwise. On the other hand, if the eccentric roll wear plate  405  were to cease to apply an upward force on the wear plate  403  of the proximal end  105   b  of the adjustable connecting rod  105  while the shovel bucket  100  is positioned upright (i.e., the plane of the top of the shovel bucket  100  is perpendicular to the gravitational field), the proximal end  105   b  of the adjustable connecting rod  105  will move towards the shovel bucket  100  until the proximal end  101   b  of the fixed connecting rod  101  strikes the stop  404  of the eccentric base support  107  and the door  102  would again be locked in a closed position. 
         [0043]    Reference is now made to  FIG. 11  which shows a side view of one embodiment of the present invention and a shovel bucket  100  with a door  102  in an open position. In this embodiment, as the shovel bucket  100  has rotated counter clockwise, the door  100  has continued to open and the pivot point  201  at the distal end  101   a  of the fixed connecting rod  101  has moved even closer than in  FIG. 10  to the pivot point  203  at the distal end  105   a  of the adjustable connecting rod  105 . In addition, the lock angle θ is now more negative than in  FIG. 10  and the pivot point  202  has moved even farther above the distance between pivot point  201  and pivot point  203 . 
         [0044]    Reference is now made to  FIG. 12  which shows a side view of one embodiment of the present invention and a shovel bucket  100  with a door  102  in a fully open position. In this embodiment, the shovel bucket  100  has continued to rotate counter clockwise such that posterior  100   d  of the shovel bucket  100  is generally parallel to the ground (or, more particularly, perpendicular to the field of gravity) such that the door  102  has swung fully open and the pivot point  201  at the distal end  101   a  of the fixed connecting rod  101  has moved even closer than in  FIG. 11  to the pivot point  203  at the distal end  105   a  of the adjustable connecting rod  105 . In addition, the lock angle θ is now more negative than in  FIG. 11  and the pivot point  202  has moved even farther above the distance between pivot point  201  and pivot point  203 . 
         [0045]    When a single embodiment is described herein, it will be readily apparent that more than one embodiment may be used in place of a single embodiment. Similarly, where more than one embodiment is described herein, it will be readily apparent that a single embodiment may be substituted for that one device. 
         [0046]    In light of the wide variety of possible devices and methods, the detailed embodiments are intended to be illustrative only and should not be taken as limiting the scope of the invention. Rather, what is claimed as the invention is all such modifications as may come within the spirit and scope of the following claims and equivalents thereto. 
         [0047]    None of the description in this specification should be read as implying that any particular element, step or function is an essential element which must be included in the claim scope. The scope of the patented subject matter is defined only by the allowed claims and their equivalents. Unless explicitly recited, other aspects of the present invention as described in this specification do not limit the scope of the claims.