Abstract:
A retractable restraint device is provided for restraining cargo pallets within a fuselage of an aircraft during flight. The device includes a lock mechanism having a base that is fixedly secured within a channel in a floor of the fuselage. Two parallel channels are typically used which each contain a plurality of the locking mechanisms spaced apart therealong. Each locking mechanism includes a guide having a lock hook and a lock catch member pivotally secured thereto. The lock hook is moveable from an unlocked position into a lock position relative to the pallet by releasing the lock catch member. A biasing spring urges the lock hook into engagement with the pallet. The lock hook is retained in its unlocked position by the lock catch member, which is also spring biased and which can be engaged with a foot to release the lock member into the locked position.

Description:
FIELD OF THE INVENTION 
     The present invention relates generally to cargo restraint and location systems, and more specifically to multi-directional pallet restraints for cargo aircraft. 
     BACKGROUND OF THE INVENTION 
     Aircraft cargo restraint devices are required to secure cargo to the cargo deck of an aircraft during transport. Conventional cargo restraint devices typically secure a cargo container in either one or two orthogonal directions. Multiple restraints are required to secure the cargo. Adjacent cargo locations will often need to be left vacant to provide sufficient room for installing a number of cargo restraint devices to the cargo deck floor. As a result, hours can be expended by ground workers to restrain cargo containers for transport and to unload. This additional time results in non-revenue generating down time and extra manpower expenditures. 
     What is therefore needed is an easily actuated, compact cargo restraint system for restraining a cargo container in all three coordinate axes with a fewer number of restraint devices. 
     SUMMARY OF THE INVENTION 
     The present invention is directed to a retractable cargo restraint system. In one preferred form, the present invention provides a system to quickly locate and restrain oversize and/or overweight cargo loads to prevent movement during transportation. The system is also designed with the intent to be installed on a new or used aircraft without interfering with or negatively affecting the pre-existing, installed systems on the aircraft. The cargo restraint system utilizes pairs of locking mechanisms that are located on opposing sides of a cargo pallet. Each locking mechanism includes a base that is secured to the cargo deck and pivotally connected to a retractable guide. The guides are useful in aligning the cargo pallet on the cargo deck. The lock mechanism also includes a lock hook that is pivotally connected to the guide and engages the cargo pallet to secure the cargo pallet to the cargo deck. 
     In another preferred form, a cargo restraint system is provided that is retractable below the cargo deck, and that can be permanently installed in the aircraft so as to not interfere with other cargo handling functions when not in use. In another preferred form, the present invention incorporates a lateral guide with a lock mechanism for an aircraft cargo deck that is fully retractable below the plane of the cargo deck. 
     Further areas of applicability of the present invention will become apparent from the detailed description provided hereinafter. It should be understood that the detailed description and specific examples are intended for purposes of illustration only and are not intended to limited the scope of the invention. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     The present invention will become more fully understood from the detailed description and the accompanying drawings, wherein: 
     FIG. 1 is a partially broken away perspective view illustrating an aircraft having a cargo compartment with a restraint system constructed in accordance with the teachings of the present invention; 
     FIG. 2 is an enlarged view of a portion of FIG. 1, illustrating the restraint system in greater detail; 
     FIG. 3 is a partially exploded perspective view of a portion of the restraint system of FIG. 1, illustrating the lock mechanism in greater detail; 
     FIG. 4 is a partially exploded perspective view of the lock hook of the lock mechanism; 
     FIG. 5 is a perspective view of the lock mechanism engaged to a cargo pallet taken along the line  5  of FIG. 2; 
     FIG. 6 is a side elevation view illustrating the lock mechanism with the guide in the lowered position; 
     FIG. 7 is a side elevation view similar to FIG. 6 but illustrating the lock mechanism with the guide in the raised position adjacent a side of a pallet; 
     FIG. 8 is a side elevation view similar to FIG. 7 but illustrating the latch of the lock mechanism engaged to the pallet; 
     FIG. 9 is a side elevation view similar to FIG. 8, but illustrating the latch in a position rotated away from the pallet illustrating the alignment of the pawl and the chamfer which cooperate to maintain the latch in a stationary position relative to the guide; and 
     FIG. 10 is a front view of the apparatus shown in FIG.  8 . 
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS 
     The following description of the preferred embodiment(s) is merely exemplary in nature and is in no way intended to limit the invention, its application, or uses. 
     With reference to FIGS. 1 and 2 of the drawings, an exemplary aircraft is indicated generally by reference number  10 . Aircraft  10  includes a fuselage having a cargo deck  12 . The cargo deck  12  has a number of recessed channels  14  useful for restraining and locating a cargo container  16  (FIG.  2 ). Cargo container  16  is restrained to cargo deck  12  using a lock mechanism  20  in accordance with the teachings of the present invention. In use, typically a pair of lock mechanisms  20  are employed to secure a cargo container stationary within the fuselage. A plurality of lock mechanisms  20  are preferably arranged in two adjacent rows to better accommodate cargo containers of different sizes. 
     With specific reference to FIG. 2, cargo container  16  is secured to pallet  22  prior to being loaded onto aircraft  10 . Pallet  22  is provided with engagement pockets  24 . As best seen in FIG. 5, engagement pockets  24  have an interior surface defined in part by aft surface  26   a , bottom surface  26   b , and forward surface  26   c.  Pallet  22  is positioned between the two rows of lock mechanisms  20  and then secured for transport as discussed below. 
     Referring now to FIGS. 3-10, the lock mechanism  20  is shown in greater detail. Lock mechanism  20  includes a base  30 , a lateral guide  32 , and a lock hook  34 . Base  30  is preferably provided with mounting holes  36  for mounting within a respective one of the recessed channels  14  (FIG.  7 ). Base  30  includes recessed portions  38  and base guide apertures  40 . Lateral guide  32  includes a body  46  with a guide surface  48  and beveled edges  50 . Body  46  includes a lock hook opening  52  defining a passageway in the central portion of body  46  extending along guide surface  48  to a lower surface  54  and defining an interior surface  56 . Lateral guide  32  further includes guide legs  60  integrally formed in body  46  and extending away from body  46  along interior surface  56 . As best seen in FIG. 3, guide legs  60  are further defined by lower surface  54 . Lateral guide  32  has guide shaft apertures  64 , guide pin apertures  66 , lock apertures  68 , and stop pin apertures  74  formed through guide legs  60 . At least one guide leg  60  has an uplock slot  76  formed therethrough. Uplock slot  76  extends parallel to guide shaft aperture  64  through the thickness “t” of guide leg  60 . Uplock slot  76  is generally arc shaped with a radius of curvature about the axis of guide shaft aperture  64 . 
     Each guide pin aperture  66  intersects a corresponding guide shaft aperture  64 . Lateral guide  32  is pivotably coupled to base  30  by a guide shaft  78 . To accomplish this connection, base  30  and lateral guide  32  are positioned such that base guide apertures  40  and guide shaft apertures  64  are aligned and then a guide shaft  78  is inserted therethrough. Guide shaft  78  includes a shaft portion  80  with retaining apertures  82  formed therethrough and a head  84  integrally formed at one end. When guide shaft  78  is fully inserted within base  30  and lateral guide  32 , a guide shaft pin  86  is inserted into each guide pin aperture  66 . Guide shaft  78  is positioned such that each retaining aperture  82  aligns with one guide pin aperture  66  and guide shaft pins  86  are further inserted until they reach a fully installed position. In this position, each guide shaft pin  86  extends through one retaining aperture  82  into a single guide pin aperture  66 . In this manner, lateral guide  32  can be rotated relative to base  30 , as discussed below. Each stop pin aperture  74  has a stop pin  88  interference fit therein and extends beyond interior surface  56  (FIG.  10 ). 
     Lateral guide  32  is shown in FIG. 6 in a retracted position wherein lateral guide  32  is folded below the plane P of cargo deck  12 . Lateral guide  32  is shown in FIG. 7 in a raised positioned wherein lateral guide  32  extends above the plane P of cargo deck  12 . In this position, lateral guide  32  can abut a side of pallet  22  along the guide surface  48  of lateral guide  32  as pallet  22  is positioned on cargo deck  12 . Lateral guide  32  is shown in a preferred embodiment wherein the opposing ends of guide surface  48  each have a beveled edge  50  (FIGS.  3  and  5 ). Beveled edges  50  extend away from pallet  22 . In this manner, some misalignment of pallet  22  will not result in interference between pallet  22  and lateral guides  32 , and beveled edge  50  of lateral guide  32  can help to correct misalignment of pallet  22  as pallet  22  is located between the parallel rows of lock mechanisms  20  on cargo deck  12  (FIG.  2 ). Once pallet  22  is located between lock mechanisms  20 , lateral guides  32  will interfere with the lateral sides of pallet  22  and thereby restrict lateral movement of pallet  22 . 
     When lateral guide  32  is in the raised position, each lower portion of guide leg  60  is located within the recessed portion  38  of base  30  with lower surface  54  of lateral guide  32  generally supported by the horizontal surface of recessed portion  38  (FIGS.  5  and  7 - 10 ). During pallet positioning and transport, pallet  22  can impart cargo loading force L on guide surface  48  (FIG.  9 ). To place lateral guide  32  into the retracted position, lateral guide  32  is rotated clockwise, as shown in FIG. 6, with guide surface  48  facing base  30 . It would be readily recognized by one of ordinary skill in the art that this coupling arrangement of lateral guide  32  and base  30  provides a maximum of stability and resistance to force L as force L is translated to a moment about guide shaft  78  that is resisted by the resulting pressure between lower surface  54  and the horizontal surface of recessed portion  38 . 
     In FIGS. 2-4 and  7 , pallet  22  with cargo container  16  secured thereon is preferably located between pairs of lock mechanisms  20 . Lateral guides  32  abut pallet  22 . Lock hook  34  includes a hook  90  at a first end. The second end of lock hook  34  is defined by a cam surface  100 , a chamfer  102  and a lock hook opening  104 . Lock hook opening  104  is a cut out that extends from the central portion of lock hook  34  and opens onto the second end of lock hook  34  defining two lock hook legs  110 . Lock hook legs  110  each have a generally circular lock hook mounting aperture  112  formed therethrough such that lock hook mounting apertures  112  are axially aligned. 
     Each lock hook leg  110  has a lock retaining pin aperture  114  formed therein such that each lock retaining pin aperture  114  perpendicularly intersects one lock hook mounting aperture  112 . A lock deploy spring pin aperture  120  is formed through each lock hook leg  110  generally parallel to the lock hook mounting apertures  112 . A lock deploy spring pin  122  is interference fit into each lock deploy spring pin aperture  120  such that each lock deploy spring pin  122  extends into lock hook opening  104  (FIG.  10 ). Lock hook  34  is pivotably connected to lateral guide  32  with a lock shaft  130 . Lock shaft  130  extends through lock hook mounting apertures  112  and through axially aligned lock apertures  68  in the lateral guide  32 . Lock shaft  130  is a cylindrical shaft that includes lock shaft pin apertures  132  and an unlock lever stop aperture  134  formed therein. The axes of lock shaft pin apertures  132  and unlock lever stop aperture  134  are preferably parallel to each other and perpendicular to the axis of lock shaft  130 . When lock shaft  130  is properly inserted in lock hook mounting apertures  112  and lock apertures  68 , lock retaining pin apertures  114  align with lock shaft pin apertures  132 . A lock retaining pin  140  is then positioned within each lock retaining pin aperture  114  and corresponding lock shaft pin aperture  132  by interference fit. Preferably, the lock retaining pins  140  do not extend beyond the outer surfaces of lock hook  34  when positioned. Thus provided, lock hook  34  rotates between a locked position (FIG. 8) and an unlocked position (FIG.  7 ). In the embodiment shown, lock hook  34  rotates with lateral guide  32  as lateral guide  32  is raised from the retracted position to the raised position. Lock hook  34  is located below the plane of cargo deck  12  when lateral guide  32  is in the retracted position. 
     Referring now to FIGS. 3 and 4, the second end of lock hook  34  preferably includes a cam surface  100  and a chamfer  102 . As best seen in FIG. 9, chamfer  102  interlocks with an uplock catch mechanism  146  to maintain lock hook  34  in the unlocked position and to prevent lock hook  34  from rotating to the locked position. Uplock catch mechanism  146  preferably includes a member of unitary construction that includes a first end  148  with a pawl  150  that extends therefrom, and a second end  152  with an uplock mounting aperture  154  formed therein. Preferably, pawl  150  is a cylindrical portion that extends from uplock catch mechanism  146  perpendicular to the alignment of the first end  148  and the second end  152 . Uplock mounting aperture  154  is sized to freely rotate about guide shaft  78 . As best seen in FIG. 3, uplock catch mechanism  146  also includes an uplock catch spring  158  that includes a helical portion  160 , a first end  162  and a second end  164 . Helical portion  160  is sized to accommodate guide shaft  78  therethrough. First end  162  extends tangentially away from helical portion  160  and includes an L-portion  166  that includes the extreme end portion formed generally perpendicular to the axis of first end  162 . As seen in FIG. 10, L-portion  166  can abut the underside of uplock catch mechanism  146 . Second end  164  of uplock catch spring  158  is formed into a hook that secures to head  84  of guide shaft  78 . 
     As best seen in FIG. 10, guide shaft  78  is disposed through uplock mounting aperture  154  and uplock catch spring  158 . Pawl  150  is disposed through uplock slot  76  such that the first end  148  of uplock catch mechanism  146  abuts a surface of lateral guide  32  that surrounds uplock slot  76 . Pawl  150  extends through uplock slot  76 , beyond interior surface  56  and into interference with either cam surface  100  or chamfer  102 , depending upon the position of lock hook  34  relative to lateral guide  32 . In this manner uplock catch spring  158  urges pawl  150  of uplock catch mechanism  146  toward chamfer  102 . 
     As best seen in FIG. 8, pawl  150  of uplock catch mechanism  146  can be disengaged from chamfer  102  by using a finger or foot to rotate the first end  148  of uplock catch mechanism  146  away from chamfer  102  against the biasing force of uplock catch spring  158 . When uplock catch mechanism  146  is disengaged, a lock deploy spring  170  urges lock hook  34  into the locked position. Lock deploy spring  170  is preferably a helical spring member with lock shaft  130  disposed therethrough. 
     As seen in FIG. 8, a first end  172  of lock spring  170  is preferably coiled about guide shaft  78  and a second end  174  of each lock deploy spring  170  is preferably positioned adjacent the portion of lock deploy spring pin  122  that extends into lock hook opening  104  (FIGS.  5  and  10 ). Thus provided, lock deploy springs  170  bias lock hook  34  toward the locked position to maintain the lock hook  34  in its locked position. Uplock catch spring  158  urges pawl  150  of uplock catch mechanism  146  toward cam surface  100  as lock hook  34  rotates relative to lateral guide  32 . In the locked position, lock hook  34  extends beyond guide surface  48  and locks into engagement pocket  24 . Stop pin  88  (FIGS. 8 and 10) prevents rotation of lock hook  34  beyond the locked position. 
     Turning now to the operation of lock mechanism  20 , lock hook  34  extends above the lower portion of engagement pocket  24  when lock mechanism  20  is in the locked position (FIG.  8 ). Vertical movement of pallet  22  will be restricted by interference between lock hook  34  and bottom surface  26   b  of engagement pocket  24 . As best seen in FIGS. 2 and 8, when lock mechanism  20  is in the locked position lock hook  34  extends into engagement pocket  24 . Lock hook  34  interferes with the vertical interior surfaces  26   a ,  26   c  of engagement pocket  24  to restrict horizontal movement of pallet  22  in within the fuselage in a fore/aft direction. Thus provided, lock hook restricts the vertical, fore, and aft movement of pallet  22 . 
     Lock mechanism  20  further includes an unlock lever  180 . Unlock lever  180  includes an annular body  182  with an actuation pedal  184  extending therefrom. Annular body  182  includes a cylindrical bore  186  extending therethrough and an unlock lever stop guideway  188  extending from cylindrical bore  186  to an outer surface of annular body  182 . Unlock lever stop guideway  188  is defined in part by a first end surface  190  and a second end surface  192 . Annular body  182  of unlock lever  180  is interposed between lock hook legs  110  and lock shaft  130  is disposed through cylindrical bore  186 . Unlock lever stop guideway  188  aligns with unlock lever stop aperture  134  and an unlock lever stop  198  is inserted through unlock lever stop guideway  188  and interference fit into unlock lever stop aperture  134 . In this manner, unlock lever  180  can freely rotate about lock shaft  130  between a first position where unlock lever stop  198  contacts first end surface  190  and a second position where unlock lever stop  198  contacts a second end surface  192 . 
     As best seen in FIGS. 9 and 10, a downward force on actuation pedal  184  of unlock lever  180  causes unlock lever stop  198  to contact second end surface  192  as unlock lever  180  rotates in a counter-clockwise direction. As more downward force is applied to actuation pedal  184 , interference between unlock lever stop  198  and second end surface  192  of unlock lever stop guideway  188  causes counter-clockwise rotation of lock hook  34  from the locked position to the unlocked position. This in turn causes pawl  150  of uplock catch mechanism  146  to be urged downwardly in a counter-clockwise rotational movement by cam surface  100 . This counterclockwise rotation of lock hook  34  is resisted by lock deploy springs  170 . Further counter-rotation of unlock lever  180  forces cam surface  100  to travel beyond pawl  150  of uplock catch mechanism  146 , whereupon the biasing force of uplock catch spring  158  forces the pawl  150  of uplock catch mechanism  146  into engagement with the chamfer  102 . Lock hook  34  is then back in the unlocked position and uplock catch mechanism  146  prevents rotation of lock hook  34  to the locked position. 
     As best seen in FIGS. 5,  8  and  9 , uplock catch mechanism  146  and unlock lever  180  are preferably located on lock mechanism  20  to allow foot actuation. In operation, uplock catch mechanism  146  can be depressed by foot to cause rotation of lock hook  34  to the locked position. Unlock lever  180  can likewise be depressed by foot, urging lock hook  34  to the unlocked position. Thus provided, lock mechanism can be actuated without the use of tools. 
     The present invention thus provides a compact retractable lock mechanism for securing an item to a floor or a cargo deck. The lock mechanism is well suited for aircraft cargo transportation where an easily actuated locking mechanism can reduce the time required to secure the cargo to an aircraft cargo deck and can also reduce the time required to remove the cargo. Importantly, the present invention serves the dual purpose of functioning not only to restrain cargo in the vertical and lateral axes, but also to restrain cargo in the longitudinal (fore and aft) axis. The present invention also provides a restraint system that utilizes a pair of locking mechanisms to guide cargo to the proper location and secure the cargo in all three coordinate axes. 
     It will be appreciated also that the present invention could just as easily be implemented in any form of mobile platform (e.g., van, bus, truck, railroad car, ship, etc.) that is used for carrying cargo that needs to be restrained during transportation. 
     The description of the invention is merely exemplary in nature and, thus, variations that do not depart from the gist of the invention are intended to be within the scope of the invention. Such variations are not to be regarded as a departure from the spirit and scope of the invention.