Abstract:
An ammunition elevator device is provided for raising and lowering ammunition. The device includes a housing, a crank assembly, a pawl mechanism, and a transfer linkage. The housing has a chamber within which to elevate the ammunition flanked by first and second flanges. The assembly, rotatably disposed between the flanges, has a crank axle, first and second sprockets mounted to the axle for elevating the ammunition, and a ratchet gear mounted to the axle adjacent to the first flange. The pawl mechanism connects to the first flange and includes a pawl, a toggle and a pin spreader. The toggle pin connects to the pawl and mounts to the spreader. The transfer linkage has a rotatable bar pivotably connected to the second flange, a rod that radially shifts relative to the crank axle in response to the sprockets, and first and second rotatable joints. The first joint connects to the bar to the rod. The second joint connects the rod to the spreader. The ratchet gear connects to the axle adjacent said first flange, wherein the gear cyclically pivot the pawl for raising the toggle.

Description:
STATEMENT OF GOVERNMENT INTEREST 
       [0001]    The invention described was made in the performance of official duties by one or more employees of the Department of the Navy, and thus, the invention herein may be manufactured, used or licensed by or for the Government of the United States of America for governmental purposes without the payment of any royalties thereon or therefor. 
     
    
     BACKGROUND 
       [0002]    The invention relates generally to ammunition elevators. In particular, the invention relates to elevation mechanisms for controllably raising and lower ammunition into a magazine. 
         [0003]    Reversible (i.e., bi-directional) ratchets are utilized to great extent in hand wrenches allowing for the tightening and loosening of nuts and bolts. A ratcheting wheel engages a pawl, both having a saw-tooth groove, and is rotated in either direction with a detent coming in contact with a ball plunger to prevent unintended backwards rotation. Reversible ratchet wrenches of the type discussed above and other similar wrenches are disclosed by U.S. Pat. Nos. 260,834, 376,584, 2,542,241, 2,701,977, 3,713,356, 4,485,700, 4,631,988, 6,543,316 and 6,644,148. Ammunition lifts are used for lifting ammunition from one height to another. These were first used around 1930 to lift ammunition to the weapon system. 
         [0004]    The United States Navy has commissioned two class prototypes for a Littoral Combat Ship (LCS) intended for close shore fire support with inter-changeable weapons modules for select plug-and-fight missions. The Gun Mission Module (GMM) as an example for the surface warfare module package includes two turret-mounted, axis-stabilized chain guns that protrude above deck from a module cover, below which personnel can supply ammunition from storage containers. 
       SUMMARY 
       [0005]    Conventional ammunition lifters yield disadvantages addressed by various exemplary embodiments of the present invention. In particular, various exemplary embodiments provide for a ammunition elevator device is provided for raising and lowering ammunition. The device includes a housing, a crank assembly, a pawl mechanism, and a transfer linkage. The housing has a chamber within which to elevate the ammunition flanked by first and second flanges. 
         [0006]    In various exemplary embodiments, the assembly, rotatably disposed between the flanges, has a crank axle, first and second sprockets mounted to the axle for elevating the ammunition, and a ratchet gear mounted to the axle adjacent to the first flange. The pawl mechanism connects to the first flange and includes a pawl, a toggle and a pin spreader. The toggle pin connects to the pawl and mounts to the spreader. 
         [0007]    In various exemplary embodiments, the transfer linkage has a rotatable bar pivotably connected to the second flange, a rod that radially shifts relative to the crank axle in response to the sprockets, and first and second rotatable joints. The first joint connects to the bar to the rod. The second joint connects the rod to the spreader. The ratchet gear connects to the axle adjacent said first flange, wherein the gear cyclically pivot the pawl for raising the toggle. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0008]    These and various other features and aspects of various exemplary embodiments will be readily understood with reference to the following detailed description taken in conjunction with the accompanying drawings, in which like or similar numbers are used throughout, and in which: 
           [0009]      FIG. 1  is an isometric assembly view of an ammunition lifter; 
           [0010]      FIG. 2A and 2B  are isometric and elevation views of a toggle assembly; 
           [0011]      FIG. 3  is an isometric exploded view of the ammunition lifter; 
           [0012]      FIG. 4  is an isometric view of a frame weldment; 
           [0013]      FIG. 5  is an isometric view of right- and left-hand axle assemblies; 
           [0014]      FIG. 6A  and B are elevation views of right- and left-hand lifters; 
           [0015]      FIG. 7  is an elevation cross-section view of the left-hand lifter; 
           [0016]      FIG. 8  is an isometric of the ammunition lifter without the cover; 
           [0017]      FIG. 9  is an elevation cross-section view of the right-hand lifter; 
           [0018]      FIG. 10  is an isometric view of the lifter raising ammunition; and 
           [0019]      FIG. 11  is an isometric view of a storage locker frame for the gun mission module. 
       
    
    
     DETAILED DESCRIPTION 
       [0020]    In the following detailed description of exemplary embodiments of the invention, reference is made to the accompanying drawings that form a part hereof, and in which is shown by way of illustration specific exemplary embodiments in which the invention may be practiced. These embodiments are described in sufficient detail to enable those skilled in the art to practice the invention. Other embodiments may be utilized, and logical, mechanical, and other changes may be made without departing from the spirit or scope of the present invention. The following detailed description is, therefore, not to be taken in a limiting sense, and the scope of the present invention is defined only by the appended claims. 
         [0021]    Various exemplary embodiments enable safely transporting ammunition connected via links vertically from one height to another in either direction with a ratcheting mechanism. The conventional method for lowering ammunition for involves disengaging the ratchet. This practice leaves the operator exposed to a potential large mass, depending on the length of the chute, traveling at fast speeds, and thus constitutes a distinct hazard. Moreover, confinement of the spaces within a naval war vessel impedes movement therein. Various exemplary embodiments alleviate these ambulatory restrictions for raising ammunition to be loaded. 
         [0022]    The Gun Mission Module (GMM) for the Littoral Combat Ship (LCS) incorporates an ammunition lift that provides bi-directional raising of ratchet wrenches. Various exemplary embodiments comprise a ratchet wheel secured to a rotating shaft via a woodruff key as well as a nut and washer. The ratchet wheel engages a pawl, of mirrored proportions rotating about a pin a fixed distance from the shaft and secured in like manner as the ratchet wheel and having a spring affixed atop its center, thus acting in a ratcheting motion when rotated in either direction. 
         [0023]    Two sprockets of equal size and shape having grooves to fit the diameter of the desired ammunition are fixed on the shafts in the manner as the ratchet wheel. As the shaft rotates the sprockets lift or lower the linked ammunition. The ammunition is kept free of jamming by guiding rails spaced at intervals dependent on the geometry of the ammunition. 
         [0024]      FIG. 1  represents an isometric assembly view of an exemplary ammunition lift device  100 . Arrows depict orientation relating to the hardware for axial  110 , lateral  120  and zenith  130  directions. A housing for the lift device includes a cover  140  and a frame weldment  150 . A manual wheel  160  with an attached crank handle  165  connects to an axle assembly for operating the lift device. A ratchet toggle  170  connected to a (distal) shaft collar  175  enables engagement of a ratchet lock  180 . The weldment  150  defines a chamber  190  through which the ammunition passes. 
         [0025]    The axle assembly, discussed in further detail below, represents a right-hand version, with the wheel  160  disposed at the distal end of the frame weldment  150 . An operator can grab the handle  165  to turn the wheel  160  for lowering ammunition into the weldment  150 . Artisans of ordinary skill will recognize that the wheel  160  with its handle  165  can be replaced with a powered motor without departing from the scope of the claims. 
         [0026]      FIGS. 2A and 2B  represent respective isometric and elevation views of a toggle assembly  200 . A pawl  210  engages a pawl toggle  220  for lifting ammunition. The toggle  220  includes a pin joint  222  that connects to the pawl  210 , a base  224 , and a rod  226  that extends from the base  224 . A pin  230  pivotably secures the toggle  220  at the joint  222  to the pawl  210 . Opposite the pawl  210 , the toggle  220  connects to the pin spreader  240  by a screw  245  surrounded by a helical spring  250  disposed between the base  224  and the screw  245 . A sleeve  260  on the pawl  210  coaxially surrounds a pawl shaft  270  to pivot thereround. 
         [0027]      FIG. 3  represents an isometric exploded view  300  of the ammunition lift device  100  in substantially the same orientation as the assembly view. An extender bar  310  terminates in a proximal sleeve bearing  315  and connects collinearly with the shaft  270 . Transfer mechanism components  320  provide rotatable linkage between the bar  310  and the shaft  270 , which terminates in a distal sleeve bearing  325 . The pawl  220  is disposed at the upper portion of the weldment  150  between the bar  310  and the (upper distal) pawl shaft  270 , which engages the pawl toggle  220 . The helical compression spring  250  extends coaxially with the toggle  220 , which terminates with a pin spreader  240  opposite its pin connection with the pawl  220 . 
         [0028]    The ratchet lock  180  connects to the frame weldment  150  by lock fastening components  330 . The ratchet toggle  170  connects to the weldment  150  by toggle fastening components  340 . A set of spacer and alignment components  350  connects the collar  175  and the wheel  160  to a crank axle  360 . Distal and proximal sprockets  370 ,  380  mount to the crank axle  360 , which terminates by a proximal damper assembly  390 . 
         [0029]      FIG. 4  represents an isometric view  400  of the frame weldment  150  for the ammunition lift device  100 . The orientation in relation to the assembly view conforms to the arrows  110 ,  120  and  130  as shown. Proximal and distal flanges  410 ,  420  attach to port and starboard plates  430 ,  440  that define the chamber  190 . Each flange  410 ,  420  includes a shaft keyslot  450  for supporting the crank axle  360  and through-holes  455 ,  460  for mounting additional components. 
         [0030]    For the configuration shown, the flanges  410  and  420 , each 0.25 inch in thickness, have longitudinal separation (axial direction  110 ) by 12.75 inches. Their width and height (lateral and zenith directions  120 ,  130 ) are 7.25 and 8.00 inches, respectively. Similarly, the plates  430  and  440  have chamber separation (lateral direction  120 ) of 2.00 inches for passing 30 mm ammunition. Artisans of ordinary skill will recognize that the dimensions provided for this configuration as described are exemplary only and not limiting to the sizes and types of munition rounds on which the exemplary embodiments can operate. 
         [0031]    In particular, the pawl shaft  270  passes the through-hole  455 , and the toggle fastening components  340  for the ratchet toggle  170  connect through the hole  460 . The interior surfaces of the plates  430 ,  440  include alignment guide rails  470  for vertically sliding components therein. The starboard plate  440  includes first, second and third slots  480 ,  485  and  490 . The ammunition rounds can be raised or lowered within the chamber  190  as the connecting links traverse along the guide rails  470 . 
         [0032]      FIG. 5  shows an isometric view  500  of right- and left-hand axle assemblies  510 ,  520  (respectively) with similar components. Components can be preferably produced from ASTM A322 steel having grade 8630 and Rockwell hardness of C40 to C50. Both right- and left-hand assemblies show the axial arrow  110  towards the right. The right-hand assembly  510  features the wheel  160  at the distal end, whereas the left-hand assembly  520  features the wheel  160  at the proximal end. 
         [0033]    The right-hand assembly  510  includes a counter-clockwise ratchet gear  530  disposed along the shaft  260  between the collar  175  and the distal sprocket  270 . The left-hand assembly  520  includes a clockwise ratchet gear  540  disposed along the shaft  260  between the proximal sprocket  280  and the damper assembly  290  that includes a spindle cover  550  and a uni-directional damper  560 . As an alternative, the gear can incorporate axi-symmetric teeth for ratchet restriction using a pivotable ratchet toggle to restrict turning motion to a preferred direction. 
         [0034]    The wheel  160  attaches to the shaft  260  by a wheel nut  570 . The alternative axle assemblies  510 ,  520  can be installed through the keyslot  450  for either the right- or left-hand configuration, depending on which of the proximal or distal flanges  410 ,  420  on the frame weldment  150  that the wheel  160 , toggle  170  and lock  180  are to be mounted. 
         [0035]    The proximal and distal sprockets  380  and  370  penetrate into the chamber  190  through the respective first and second slots  480  and  485 , with their teeth engaging the ammunition rounds. The gear  530  or  540  protrudes into the chamber  190  through the third slot  490 . The damper  560  enables an operator to release the toggle  220  while restraining the ammunition within the chamber  190  from precipitously falling out therefrom. 
         [0036]      FIGS. 6A and 6B  present elevation views  600  of right- and left-hand lifters  610 ,  620  (respectively). The right-hand lifter  610  features the wheel  160  at the distal end adjacent the counter-clockwise ratchet gear  530 , whereas the left-hand lifter  620  features the wheel  160  at the proximal end opposite the clockwise ratchet gear  540 , as indicated by the respective axial and zenith directional arrows  110 ,  130 . 
         [0037]    A sprocket linkage joint  630  connects the extender bar  310  to a transfer rod  640  that shifts radially outward from the crank axle  360  as the sprockets  370 ,  380  turn. An opposing linkage connects the extender bar  310  to the pawl shaft  270 . The transfer rod  640  and extender bar  310  enable support for the pawl  210  to pivot on the pawl shaft  270  without interfering with movement of the gears  370 ,  380 . 
         [0038]      FIGS. 6A and 6B  present elevation views  600  of right- and left-hand lifters  610 ,  620  (respectively). The right-hand lifter  610  features the wheel  160  at the distal end adjacent the counter-clockwise ratchet gear  530 , whereas the left-hand lifter  620  features the wheel  160  at the proximal end opposite the clockwise ratchet gear  540 , as indicated by the respective axial and zenith directional arrows  110 ,  130 . 
         [0039]    In left hand configuration  620 , the linkage joint  630  connects the extender bar  310  to a transfer rod  640  that transmits radial motion from the toggle  170  to the pawl  210 . The toggle  170  is locked in place in both right- and left-hand configurations by ratchet lock  180 . Locking the toggle  170  in position by the ratchet lock  180  prevents the pawl  210  from coming into contact with the ratchet gear  530 . Thus gravity pulls the ammunition downward (opposite of  130 ). This engages the uni-directional damper  560  to retard the ammunition on its descent. 
         [0040]      FIG. 7  represents an elevation view  700  of a left-hand lifter  620  as observed at the distal flange  420  from the proximal end looking forward (i.e., within the weldment  150 ), as indicated by the lateral and zenith directional arrows  120 ,  130 . The pawl  210  pivots on the shaft  270  to move the toggle  220  vertically. 
         [0041]    The clockwise ratchet gear  540  restricts the pawl  210  to gradual upward or else abrupt downward motion. (The counter-clockwise ratchet gear  530  similarly restricts the pawl  210  for the right-hand lifter  610  on the distal flange  420 .) The bearing  325  pivotably maintains the shaft  270  within the hole  455  in the distal flange  420 , while the bar  310  connects to the hole  455  in the proximal flange  410 . The sprockets  370  and  380  rotate along the crank axle  360  in conjunction with the gear  540 . 
         [0042]      FIG. 8  represents an elevation view  800  of the ammunition lift device  100  without the cover  140  for the frame weldment  150 . The crank axle  360 , having the gears  370 ,  380  attached thereon, is disposed within the keyslot  450  of the opposing flanges  410 ,  420 . The extender bar  310  connects between the through-hole  455  of the proximal flange  410  and the linkage joint  630  for the transfer rod  640 . 
         [0043]      FIG. 9  represents an elevation view  900  of a right-hand lifter  610  as observed at the proximal flange  410  from the distal end looking aft (i.e., within the weldment  150 ). As the gears  370  and  380  turn counter-clockwise  910  on the crank axle  360 , their sprocket teeth  920  protrude through the respective slots  485  and  480 . The teeth  920  raise concatenated rounds  930  of 30 mm ammunition by engaging their links  940  upward through the chamber  190 . 
         [0044]      FIG. 10  represents an isometric view  1000  of the ammunition lift device  100  (without the cover  140 ) lifting concatenated rounds  930  through the chamber  190 .  FIG. 11  represents an isometric view  1100  of a storage locker frame around the GMM equipped with upper and lower devices  100 . This frame includes a munitions assembly platform  1110  (represented by an open fold-down door of a stowage magazine) from which at least one ammunition lifter  100  elevates the concatenated rounds  930  to a loading platform  1120  for the chain gun. 
         [0045]    Various exemplary embodiments of the ammunition lifter feature advantages such as a safety mechanism for bi-directional use. By lifting the ratchet toggle handle  170  (e.g., via an operator), the ratchet lock  180  pushes upwards, disengaging the toggle pawl assembly  200  from the ratchet gear  530 ,  540 . Gravity then pulls the ammunition rounds downward, which engages the uni-directional damper  560  to apply friction that retards the descent of the rounds. The ammunition  930  then can be lowered at a controlled rate to the lower level without potential injury to the operator. The ratchet gear  530 ,  540  engaged with the pawl  210  provides for improvements in safety by restricting motion to the intended (descent) direction. 
         [0046]    Another advantage from various exemplary embodiments constitutes the mirror design features. In particular, the assembly for the crank axle  360  can be installed within the weldment  150  with the wheel  160  mounted on either the distal plate  420  in the right-hand configuration  510  or else on the proximal plate  410  in the left-hand configuration  520 , as a reversal to the right-hand configuration  510 . This enables the operator to lift ammunition  930  from either end, such as a munitions round forward (as shown in view  1100 ), or alternatively a clip forward, thereby augmenting versatility. 
         [0047]    This mirror complimentary feature may be necessitated due to the dual canister mirror loading style of the Mk46 chain gun for the GMM, and as such reduces operator reloading time and potential confusion. The transfer rod  640  and the extender bar  310  attach to the ratchet lock  180  so that the ammunition lift device  100  operates as shown in the assembled configuration. Typically, the pawl assembly  200  pivots about the hole  460  in the distal plate  420 , although mounting to the corresponding position on the proximal plate  420  can also be accomplished. 
         [0048]    While certain features of the embodiments of the invention have been illustrated as described herein, many modifications, substitutions, changes and equivalents will now occur to those skilled in the art. It is, therefore, to be understood that the appended claims are intended to cover all such modifications and changes as fall within the true spirit of the embodiments.