Abstract:
A load transfer accessory for a loading apparatus such as a crane. The load transfer accessory is a holding mechanism that reduces unwanted movement in cylindrical cargos. The holding mechanism includes an attachment frame, a receiving member and an indexing clutch. The receiving member includes a curved surface for receiving the cylindrical cargo. The indexing clutch can be adjustably locked by wire rope tension to clock the receiving member in a desired angular orientation for loading operations.

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
     This application claims the benefit of U.S. Provisional Application No. 62/057,729, filed Sep. 30, 2014, titled “Load Transfer Accessory For Diminishing Unwanted Motion Of Cylindrical Cargo During Loading Operations”, incorporated herein by reference. 
    
    
     STATEMENT OF GOVERNMENT INTEREST 
     The following description was made in the performance of official duties by employees of the Department of the Navy, and, thus the claimed invention may be manufactured, used, licensed by or for the United States Government for governmental purposes without the payment of any royalties thereon. 
    
    
     TECHNICAL FIELD 
     The following description relates generally to a load transfer accessory for a loading apparatus such as a crane. More specifically, the load transfer accessory controls and reduces unwanted movement in cylindrical cargo during loading operations. 
     BACKGROUND 
     Load transfer apparatuses such as cranes typically use hooks and other known fastening devices to secure loads to the device, after which the fastened load is lifted from an original position and transferred to a desired position. One common problem associated with load transfer apparatuses is that the lifted load tends to swing freely, like a pendulum. When cargo swings in this manner, difficulty will naturally be experienced in transferring and lowering the cargo accurately to the desired position. 
     This problem is compounded when the cargo is delicate or a special care item. Additionally, cargo articles having different shapes may each display unique balance-related swinging motions on account of their respective shapes. For example, cargo having cylindrical shapes may swing more uncontrollably because of the elongated longitudinal axis. Preventing unwanted cargo swinging is further compounded in situations when the load transfer apparatus is mounted on a water vessel, such as a barge or small boat, or the like. There is more movement not associated with land-based operations because the load transfer apparatus is on water, even when the water is calm. Thus, it is desired to have a load transfer apparatus that reduces undesired movement of the load during load transfer operations, particularly undesired movement associated with loads having cylindrical shapes. 
     SUMMARY 
     In one aspect, the invention is a load transferring apparatus having a boom and a jib pivotally attached to the boom. The load transferring apparatus also includes a holding mechanism for controllably receiving cylindrical cargo and diminishing undesired motion of said cylindrical cargo. In this aspect, the holding mechanism has an attachment frame pivotally attached at a pivot point to the jib. The holding mechanism also includes a receiving member for receiving cylindrical cargo thereon. The receiving member has a curved inner surface, wherein the curved inner surface has a radius of curvature that is substantially equal to the radius of curvature of said cylindrical cargo. In this aspect, the holding mechanism also includes an indexing clutch or connected to and between the attachment frame and the receiving member. The indexing clutch has an upper plate having a bottom surface having a plurality of downward projecting ridges, and a lower plate having a top surface having a plurality of upward projecting ridges for mating with the downward projecting ridges of the upper member to lock the upper plate with respect to the lower member at different positions to clock the receiving member in a desired angular orientation. Each of the attachment frame, the upper and lower plates of the indexing arrangement, and the receiving member have a central opening that forms a central pathway. In this aspect the load transfer apparatus also has a winch, and a cable having a hook at one end and attached to the winch at another. The cable extends from the winch at one end through the central pathway, with the hook positioned below the receiving member for hooking the cylindrical cargo. In this aspect, when the winch is activated the cylindrical cargo is pulled against the receiving member, thereby holding said cylindrical cargo against the curved inner surface. 
     In another aspect, the invention is a holding mechanism for controllably receiving cylindrical cargo and diminishing undesired motion of said cylindrical cargo. The holding mechanism has an attachment frame pivotally attached at a pivot point to a jib of a load transferring apparatus. In this aspect, the holding mechanism also includes a receiving member for receiving cylindrical cargo thereon, the receiving member having a curved inner surface, wherein the curved inner surface has a radius of curvature that is substantially equal to the radius of curvature of the cylindrical cargo. The holding mechanism also includes an indexing clutch connected to and between the attachment frame and the receiving member. The indexing clutch has an upper plate having a bottom surface having a plurality of downward projecting ridges, and a lower plate having a top surface having a plurality of upward projecting ridges for mating with the downward projecting ridges of the upper member to lock the upper plate with respect to the lower member at different positions to clock the receiving member in a desired angular orientation. Each of the attachment frame, the upper and lower plates of the indexing arrangement, and the receiving member have a central opening that forms a central pathway. In this aspect, the holding mechanism also has a cable having a hook at one end and attached to a winch at another. The cable extends from the winch at one end through the central pathway, with the hook positioned below the receiving member for hooking the cylindrical cargo. When the winch is activated the cylindrical cargo is pulled against the receiving member, thereby holding the cylindrical cargo against the curved inner surface. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       Other features will be apparent from the description, the drawings, and the claims. 
         FIG. 1  is an exemplary schematic illustration of a load transfer apparatus having a holding mechanism for controllably receiving cylindrical cargo, according to an embodiment of the invention. 
         FIG. 2  is an exemplary perspective illustration of a holding mechanism for controllably receiving cylindrical cargo, according to an embodiment of the invention. 
         FIG. 3  is an exemplary side view of the receiving member and a cylindrical cargo, according to an embodiment of the invention. 
         FIG. 4  is an exemplary side view of a holding mechanism for controllably receiving cylindrical cargo, according to an embodiment of the invention. 
         FIG. 5  is an exemplary section view of a holding mechanism for controllably receiving cylindrical cargo, according to an embodiment of the invention. 
         FIG. 6A  is an exemplary section view showing the operation of the holding mechanism, according to an embodiment of the invention. 
         FIG. 6B  is an exemplary section view showing the operation of the holding mechanism, with the cylindrical cargo cradled against the inner surface of the receiving member, according to an embodiment of the invention. 
         FIG. 6C  is an explanatory illustration, outlining the operation of the holding mechanism, when the cylindrical cargo is cradled against the inner surface of the receiving member (as shown in  FIG. 6A ), according to an embodiment of the invention. 
         FIG. 7  is an exemplary section view of a holding mechanism attached to a jib for controllably receiving cylindrical cargo, according to an embodiment of the invention. 
     
    
    
     DETAILED DESCRIPTION 
       FIG. 1  is an exemplary schematic illustration of a load transfer apparatus  100  having a holding mechanism  200  for controllably receiving cylindrical cargo  300  and diminishing undesired motion, according to an embodiment of the invention. As shown, the load transfer apparatus  100  is a crane, but according to other embodiments may be any other known load transfer apparatus. According to this particular embodiment, the crane  100  is an extending boom crane having a boom  110 , which as in known in cranes and as illustrated, is rotatable in direction A. A jib  120  is pivotally attached to the boom  110 , partially rotatable in direction B, adjusting the angle β between the boom  110  and the jib  120 .  FIG. 1  shows the load transfer accessory, holding mechanism  200  attached at the end of the jib  120 .  FIG. 1  also shows a cable  130  that extends through the holding mechanism. In combination with the cable  130 , the holding mechanism  200  holds the cylindrical cargo  300  at a surface of the holding mechanism and provides control of unwanted swaying in direction C. The cylindrical cargo  300  may be any type of cargo having a cylindrical shape, such as a container, a construction pipe, or a water vessel such as an unmanned underwater vessel. 
     As shown, the load transfer apparatus  100  is mounted on a platform  101 . According to an embodiment of the invention, the platform  101  is a floating platform such as a barge or small boat or other vessel that is on open water. As outlined below, the load transfer apparatus  100  equipped with the holding mechanism  200  is structured to controllably receive cylindrical cargo  300 , preventing undesired swinging of the cylindrical cargo  300 , even in embodiments when conditions are difficult because the load transferring operations being performed on open water. It should be noted that in embodiments in which the platform  101  is floating on open water, the adjustability outlined above, such as the ability to rotate in directions A and B facilitates easy loading. For example, the rotation direction B, which adjusts the angle β between the boom  110  and the jib  120 , facilitates the capturing of loads below in the water, when angle β is less than 90 degrees. 
       FIG. 2  is an exemplary perspective illustration of a load transfer accessory, holding mechanism  200 , for controllably receiving cylindrical cargo  300  and diminishing undesired motion, according to an embodiment of the invention. According to one embodiment, the holding mechanism  200  is designed as an accessory to the crane  100 , which according to this embodiment is an extending boom crane. According to this embodiment, the holding mechanism  200  may be quickly installed when the mission dictates the at-sea recovery of a cylindrical load, such as a water vessel. Thus the standard crane hook may be removed and the holding mechanism  200  may be used by inserting an attachment device, such as a pin  211  (shown in  FIGS. 3 and 5 ). 
     As shown, the holding mechanism  200  has an attachment frame  210  which attaches the holding mechanism  200  to the load transfer apparatus  100 .  FIG. 2  shows the attachment frame  210  pivotally attached to the jib  120 . As outlined below, unwanted pivoting between the attachment frame  210  and the jib is significantly reduced by the tensioning of the cable  130  and the weight of the cylindrical cargo  300 . 
       FIG. 2  also shows the holding mechanism  200  having a receiving member  220  for receiving cylindrical cargo  300  thereon. The receiving member  220  has a curved outer shell  222  that may be made from a hard material such as a metal or a composite material. The receiving member  220  also has a curved inner surface  224  that is made from a thick firm foam material. The curved inner surface  224  makes contact with the cylindrical cargo  300  when the load  300  is held by the holding mechanism  200 . The foam may be a firm foam material, such as a low density polyethylene covered by a polyurethane top coat. 
     In order to properly receive the cylindrical cargo  300 , the curvature of the receiving member  220  must match the curvature of the cylindrical cargo  300 . Consequently, each of the curved outer shell  222  and the curved inner surface  224  have a radius of curvature that is substantially equal to the radius of curvature of the cylindrical cargo  300 .  FIG. 3  is an exemplary side view of the receiving member  220  and a cylindrical cargo  300 , showing substantially the surfaces  222  and  224  having a radius of curvature that is substantially equal to the radius of curvature of the cylindrical cargo.  FIG. 3  shows both the receiving member  220  and the cylindrical cargo having a radius of curvature Rn, where n is any desired value. According to one embodiment, n=8.63. 
     Returning to  FIG. 2 , as illustrated, the holding mechanism also includes an indexing clutch  230 . As shown the indexing clutch  230  is positioned between the attachment frame  210  and the receiving member  220 .  FIG. 2  shows the indexing clutch  230  having an upper plate  232  and a lower plate  234  rotatably indexable with respect to each other. Both the upper and lower plates  232  and  234  may preferably be a solid foam material, such as a low density polyethylene covered by a polyurethane top coat. The height of the indexing clutch teeth may be adjusted to suit the resistance to rotation required by the dynamic forces associated with the platform  101  in a seaway and the tendency of the load  300  to rotate and sway in an uncontrolled manner. As outlined below the plates  232  and  234  are used to rotate the receiving member  220  to a desired orientation about an axis Y, as shown by arrow D. According to an embodiment of the invention, the upper and lower plates  232  and  234  may be rotated manually. 
       FIG. 4  is an exemplary side view of a holding mechanism  200 , including the indexing clutch  230 , for controllably receiving cylindrical cargo  300  and diminishing undesired motion, according to an embodiment of the invention.  FIG. 4  shows the indexing clutch  230  having an upper plate  232  and a lower plate  234 . As shown, the upper plate  232  has a bottom surface with a plurality of downward projecting ridges  233 .  FIG. 4  also shows a lower plate having a top surface having a plurality of upward projecting ridges  235  for mating with the downward projecting ridges  233  of the upper plate  232 . The respective downward projecting ridges  233  and upward projecting ridges  235  mate to clock the upper member  232  with respect to the lower member  234  at different angular positions. 
       FIG. 4  also shows the Y axis extending through the holding mechanism  200 . As stated above, the plates  232  and  234 , with respective interlocking ridges  233  and  235  are used to rotate the receiving member  220  to a desired angular orientation about the axis Y, so that the receiving member aligns with the cylindrical cargo  300 .  FIG. 4  also shows an X axis extending through a pivot point  215 , about which the holding mechanism  200  is pivotally mounted, via the attachment frame  210 .  FIG. 4  also shows the cylindrical cargo  300  cradled against foam curved inner surface  224  of the receiving member  220 . 
       FIG. 5  is an exemplary section view of the holding mechanism  200  for controllably receiving cylindrical cargo  300  and diminishing undesired motion, according to an embodiment of the invention. The  FIG. 5  sectional view is through  5 - 5 ′ shown in  FIG. 4 .  FIG. 5  also shows how the cylindrical cargo  300  is cradled into the receiving member  220 . 
       FIG. 5  shows, the attachment frame  210 , the receiving member  220 , and the indexing clutch  230 .  FIG. 5  also shows each of the attachment frame  210 , the receiving member  220 , and the indexing clutch  230  having respective central openings, forming a central pathway  250 . Regarding the indexing clutch  230 , each of the upper and lower plates  232  and  234  have openings.  FIG. 5  shows the cable  130  extending through the central pathway  250 . At one end, the cable  130  has a hook  135 . The hook end of the cable  130  extends out of the receiving member  220 . The other end of the cable  130  is attached to a winch  400 , which may be positioned on the load transfer apparatus  100 . As outlined below, the winch  400  may be activated to control the cable  130 , and any load attached to the cable  130 .  FIG. 5  shows the cable wrapped around a wheel  170  in the attachment frame  210 , the wheel  170  redirecting the path of the cable  130  towards the winch  400 . Although  FIG. 5  shows one wheel  170 , more than one wheel may be used to redirect the cable  130  as desired. 
       FIG. 6A  is an exemplary section view showing the operation of the holding mechanism  200 , according to an embodiment of the invention.  FIG. 6A  shows the cable  130  extending through the central pathway  250 .  FIG. 6  shows the cable  130  and hook  135  in a first position being attached to a corresponding connection ring  301  on the cylindrical cargo  300 , shown in dotted lines.  FIG. 6A  also shows the cable  130  and hook  135  in a cradled second position (in solid lines) against the receiving member  220 . In operation, the hook  135  is attached to the connection ring  301 , and the winch  400  is activated and draws the cylindrical cargo  300  upwards until it contacts the foam curved inner surface  224  of the receiving member  220 . 
     It should be noted that at some point before the cable  130  pulls in the cylindrical cargo  300  against the receiving member  220 , the indexing clutch  230  is adjusted to align the receiving member  220  with the cylindrical cargo  300 . As outlined above, the upper and lower plates  232  and  234  are rotated with respect to each other, locking the respective downward projecting ridges  233  and upward projecting ridges  235 , clocking the upper member  232  with respect to the lower member  234  at a desired angular orientation. This results in the receiving member  220  being oriented about the Y axis, in proper alignment with the cylindrical cargo  300 . With this alignment, the cylindrical cargo  300  is properly cradled within the receiving member  220 , and because the receiving member  220  and the cylindrical cargo  300  have substantially the same radius of curvature Rn, the cradling is precise, which adds stability to the load transfer process, diminishing undesired rocking or swaying of the cylindrical cargo  300 . 
       FIG. 6B  is an explanatory illustration, outlining the operation of the holding mechanism  200 , when the cylindrical cargo  300  is cradled against the inner surface  224  of the receiving member  220  (as shown in  FIG. 6A ), according to an embodiment of the invention. The explanatory view of  FIG. 6B  also shows the attachment frame  210  pivotally connected to the jib  220  at the pivot point  215 , about which the holding mechanism  200  is structured to pivot, about the X axis (shown in  FIGS. 5 and 6A ). The holding apparatus  200  in combination with the load transfer apparatus  100  diminishes undesired motion of the cylindrical cargo  300 . 
       FIG. 6B  illustrates how different interacting forces help to limit the motion of the cylindrical cargo  300 .  FIG. 6B  shows a force L that is created by the cylindrical cargo  300  pressing against the receiving member  220 .  FIG. 6B  also shows the tension T in the cable  130  due to the pulling by the winch  400 . The tension T counterbalances the force L of the cargo  300 . These forces T and L create a moment M about the pivot point  215  which substantially prevents undesired rotation/motion of the holding mechanism  200  about the pivot point  215 . In other words, the moment M prevents free swinging of the holding mechanism  200 , keeping the holding mechanism steady. According to other embodiments, the holding mechanism  200  or the jib  120  may include on or more complementary abutting members that physically prevent the rotation of the holding mechanism  200  about the pivot point  215 . 
       FIG. 6C  is an explanatory illustration, outlining the operation of the holding mechanism  200 , when the cylindrical cargo  300  is cradled against the inner surface  224  of the receiving member  220  (as shown in  FIG. 6A ), according to an embodiment of the invention. When the cylindrical cargo  300  is cradled/abutting against the receiving member  220 . In the cradled position as shown in the explanatory illustration of  FIG. 6C , the foam members, i.e., the upper member  232 , the lower member  234 , and inner surface  224 , being compressed by Δt 1 , Δt 2 , Δt 3  respectively, which is a fraction of the respective thicknesses t 1 , t 2 , and t 3 . This results in an overall compression of Δt. 
     This total Δt compression is represented as a segment of the cable  130 , shown in  FIG. 6C , i.e., the extra distance the cable travels due to the total compression. By travelling this Δt distance, the cable  130  provides a reaction time Δs for a manual operator to stop the winch  400 , and thereby stopping the winding of the cable  130 . Thus, in operation, an operator has Δs time to stop the winch, which represents the time the cylindrical cargo  300  is initially contacts the receiving member  220  to the time the compression Δt is completed. This reaction time may be increased by increasing the thickness of the foam members, i.e., the upper member  232 , the lower member  234 , and inner surface  224 . In other words, a larger t value results in a larger Δt, resulting in a larger Δs reaction time. The greater the reaction time, the greater the ability to stop the winch  400  before any potential damage is done to the cylindrical cargo  300  by pulling it too hard against the receiving member  220 . Consequently for the form members outlined above, a foam with an appropriate thickness t is selected so that the cradling process does not damage the cylindrical cargo  300 . As outlined above, the cylindrical cargo  300  may be any type of cargo, such as a container, a construction pipe, or a water vessel, having a cylindrical shape. It should be noted that the winch  400  may also be controlled automatically by a controller that utilizes the Δt and Δs variables in programming an automatic cut off for the winch  400 . 
       FIG. 7  is an exemplary section view of the holding mechanism  200  for controllably receiving cylindrical cargo  300  and diminishing undesired motion, according to an embodiment of the invention. The  FIG. 7  sectional view is through  5 - 5 ′ shown in  FIG. 4 . The  FIG. 7  illustration is similar to the illustration of  FIG. 5 , and thus like elements are referenced by the same numbers used in  FIGS. 1-5 . Thus,  FIG. 7  shows the attachment frame  210 , the receiving member  220 , and the indexing clutch  230 .  FIG. 7  also shows each of the attachment frame  210 , the receiving member  220 , and the indexing clutch  230  having respective central openings, forming a central pathway  250 .  FIG. 7  shows the cable  130  extending through the central pathway  250 . At one end, the cable  130  has a hook  135 . 
     The embodiment of  FIG. 7  differs from the illustration of  FIG. 5  in that the cable  130  extends from the central pathway  250  in the holding mechanism  200  to a wheel  171  located in the jib  120 , the wheel  171  redirecting the path of the cable  130  towards the winch  400 . Thus, the cable  130  extends within the jib  120 . As with the embodiment of  FIG. 5 , the hook end of the cable  130  extends out of the receiving member  220 . 
     Regarding the operation of the loading apparatus  100  and holding mechanism  200  as shown in  FIG. 7 , the operation is also defined as outlined with respect to  FIGS. 6A-6C . Thus for example, as illustrated in  FIG. 6A , when the winch  400  is activated, the cable  130  running through the jib  120  and central pathway  250 , draws the cylindrical cargo  300  upwards until it contacts the foam curved inner surface  224  of the receiving member  220 . Also, as with the illustration of  FIG. 6C , the  FIG. 7  embodiment, because of Δt 1 , Δt 2 , Δt 3  compressions in the upper member  232 , the lower member  234 , and inner surface  224 , respectively, resulting in an overall compression of Δt. This combined compression translates to a reaction time Δs for a manual operator to stop the winch  400 . 
     Regarding the limiting the motion of the cylindrical cargo  300  as outlined in  FIG. 6B , the embodiment of  FIG. 7  utilizes the forces T and L, as outlined above. However, the physical structure of the apparatus shown in  FIG. 7  also prevents undue rotation of the holding mechanism  200 , with respect to the jib  120 .  FIG. 7  shows, a limited rotation arc E between the jib  120  and the upper plate  232  of the indexing clutch. During the tensioning of the cable  130 , the holding apparatus  200  may rotate. However, there is no rotation beyond the arc D, because the upper plate  232  would abut against the jib  120 , preventing any further rotation. This feature adds stability to both the apparatus and the loading procedure. 
     What has been described and illustrated herein are preferred embodiments of the invention along with some variations. The terms, descriptions and figures used herein are set forth by way of illustration only and are not meant as limitations. For example, as stated above, the holding mechanism  200  may be quickly installed when the mission dictates the at-sea recovery of a cylindrical load, such as a water vessel. Thus the standard crane hook may be removed and the holding mechanism  200  may be used by inserting an attachment device, such as a pin  211 . Alternatively, the load transfer apparatus  100  may be manufactured with a non-replaceable holding mechanism  200 . Also, for example, the indexing clutch  230  may be replaced by mating high friction surfaces that also lock at desired positions thereby clocking the receiving member  220  at a desired angular orientation. Those skilled in the art will recognize that many variations are possible within the spirit and scope of the invention, which is intended to be defined by the following claims and their equivalents, in which all terms are meant in their broadest reasonable sense unless otherwise indicated.