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You are an expert at summarizing long articles. Proceed to summarize the following text: 
BACKGROUND OF THE INVENTION  
       [0001]     The present invention relates to handle extenders and in particular to a handle extender for sliding over a shipping-container door handle to provide improved leverage and an improved grip.  
         [0002]     Large shipping-containers are generally used to facilitate shipping by ship, rail, and truck. The containers are stacked in and on container ships, and the same container may be loaded onto suitable rail cars for movement over rail lines, and onto trailers pulled by trucks on the highways. Such containers generally have side by side doors in the rear of the trailer. The doors are held closed by vertical bars running between latches at the top and bottom of the doors, and each door may have one or two vertical bars and associated latches. The latches are operated by rotating the vertical bars using a handle mounted to the vertical bars.  
         [0003]     The container door handle is fairly short and is difficult to grasp with more than one hand. The handles may operate fairly easily on a new door, but as the latches wear, and metal becomes corroded, the handles often become difficult to operate. Further, in harsh and/or cold weather, the operator may need to wear gloves, and it may be even more difficult to grasp and operate the door handles. As a result, truck drivers rely on various tools to assist in moving the door handles, for example, ball pins hammers, crowbars, large Crescent wrenches, blocks of wood, or very large screwdrivers. Because such tools were designed for different application, in some cases the missuse of such tools results in a variety of injuries to the drivers. Such as broken or bruised fingers, broken hand bones, sprained or broken wrists or arms, or various injuries to the shoulders or back.  
         [0004]     Additionally, releasing a trailer requires operating a fifthwheel release latch. The fifthwheel latch generally includes a small handle located close to the trailer plate. The trailer plate is generally heavily coated with grease to avoid metal to metal contact between the fifthwheel and trailer, and the fifthwheel latch handle may become both slippery and dirty as a result.  
         [0005]     Thus, a need remains for a tool designed specifically for container door handles, which tool address the issues of safety and safe operation of opening and closing container doors with injury or other mishap, and which improves productive.  
       BRIEF SUMMARY OF THE INVENTION  
       [0006]     The present invention addresses the above and other needs by providing a door handle extender for a shipping-container (also known as a dismountable cargo container), a dry freight unit, or a refrigerator unit. The door handle is attached to a vertical locking bar which is rotated to hook and to unhook latches residing at the top and bottom of the shipping-container door. The latches engage locking housings attached to the shipping-container to lock the doors. The door handle extender comprises an offset arm with a grasping portion at one end and an engaging portion at an opposite end. The engaging portion includes a substantially oval door handle mouth for sliding over the door handle. The door handle mouth is sized and shaped to nonrotatingly engage the door handle. The grasping portion includes a soft covering to allow a firm two handed grip. The door handle extender is offset to clear an adjacent vertical bar and may further include a notch configured to engage a fifthwheel release handle to facilitate releasing a trailer. Similar door handles are used on semitrailers pulled by truck tractors, and the door handle extender is equally suitable for such semitrailers.  
         [0007]     In accordance with one aspect of the invention, there is provided a truck trailer tool comprising a door handle extender and a fifthwheel release handle extender. The door handle extender comprises an arm having a first end and a second end opposite the first end, an engaging portion of the arm, the engaging portion proximal to the first end, the engaging portion having a mouth configured to nonrotatingly engage the door handle, and a grasping portion of the arm sufficiently long to allow a two handed side by side grip of the grasping portion. A center portion resides between the engaging portion and the grasping portion. A first bend resides between the engaging portion and the center portion and a second bend resides between the center portion and the grasping end. The grasping portion is substantially parallel to the engaging portion and the center portion is angled to offset the grasping portion from the engaging portion. A fifthwheel handle notch resides proximal to the engaging portion for hooking over a fifthwheel handle to release a trailer.  
     
    
     BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWING  
       [0008]     The above and other aspects, features and advantages of the present invention will be more apparent from the following more particular description thereof, presented in conjunction with the following drawings wherein:  
         [0009]      FIG. 1A  is a side view of a tractor and trailer carrying a container.  
         [0010]      FIG. 1B  is a top view of the tractor and trailer carrying the container.  
         [0011]      FIG. 2  is a rear view showing the container on the trailer and including details of container doors.  
         [0012]      FIG. 3A  is a top view taken along line  3 - 3  of  FIG. 2 , showing handles used to hook and unhook container door latches, with the latches hooked and the doors closed.  
         [0013]      FIG. 3B  is a top view taken along line  3 - 3  of  FIG. 2 , showing the handles used to hook and unhook the container door latches, with the latches unhooked and the doors closed.  
         [0014]      FIG. 3C  is a top view taken along line  3 - 3  of  FIG. 2 , showing the handles used to hook and unhook the container door latches, with the latches unhooked and the doors open.  
         [0015]      FIG. 4A  is a side view of a door handle extender according to the present invention.  
         [0016]      FIG. 4B  is a top view of the door handle extender according to the present invention.  
         [0017]      FIG. 4C  is an end view of the door handle extender according to the present invention.  
         [0018]      FIG. 4D  is a cross-sectional view taken along line  4 D- 4 D of  FIG. 4A  of a loop attached to the door handle extender.  
         [0019]      FIG. 5  shows an engaging portion of the door handle extender, a center portion of the door handle extender, and a grasping portion of the door handle extender.  
         [0020]      FIG. 6  shows a trailer door with the door handle extender engaging a handle.  
         [0021]      FIG. 7A  is a top view of the door handle extender engaging a handle with the handle in the hooked position.  
         [0022]      FIG. 7B  is a top view of the door handle extender engaging a handle with the handle in the unhooked position.  
         [0023]      FIG. 8A  is a top view of a tractor showing a trailer plate.  
         [0024]      FIG. 8B  is a top view of the tractor showing the door handle extender engaging a fifthwheel handle attached to the trailer plate.  
         [0025]      FIG. 9  is a method according to the present invention.  
     
    
       [0026]     Corresponding reference characters indicate corresponding components throughout the several views of the drawings.  
       DETAILED DESCRIPTION OF THE INVENTION  
       [0027]     The following description is of the best mode presently contemplated for carrying out the invention. This description is not to be taken in a limiting sense, but is made merely for the purpose of describing one or more preferred embodiments of the invention. The scope of the invention should be determined with reference to the claims.  
         [0028]     A side view of a tractor  26  and trailer  24  carrying a container  10  is shown in  FIG. 1A , and a is a top view of the tractor  26  and trailer  24  carrying the container  10  is shown in  FIG. 1B . The forward end of the trailer  10  is supported by a trailer plate  28  attached to the tractor  26 . Doors  12   a  and  12   b  (see  FIG. 2 ) at a rearward end of the container  10  are held closed by latches  18  at the tops and bottoms of the doors  12   a  and  12   b , and the latches  18  may be hooked and unhooked by vertical bars  16 .  
         [0029]     A rear view showing the container  10  on the trailer  24  and including details of the container doors  12   a  and  12   b  is shown in  FIG. 2 . The doors  12   a  and  12   b  are generally connected to the trailer  24  by hinges  14  along the outside edges of the doors  12   a  and  12   b . The doors  12   a  and  12   b  are held in a closed position by latches  18  at the tops and bottoms of the doors. The latches  18  are attached to vertical bars  16 , and the vertical bars  16  may be rotated by handles  20  to hook the latches  18  to hold the doors  12   a  and  12   b  closed, and the vertical bars  16  may be rotated by handles  20  to unhook the latches  18  to release the doors  12   a  and  12   b  for opening. Common containers  10  include a pair of vertical bars  16  and four latches  18  on each door. The handles  20  generally may be rotated along a first arc  22  to fold the handles  20  against the vertical bars  16 .  
         [0030]     A top view taken along line  3 - 3  of  FIG. 2 , showing handles  20  positioned corresponding to the latches  18  (see  FIG. 2 ) hooked, and the doors  12   a  and  12   b  closed is shown in  FIG. 3A , a top view taken along line  3 - 3  of  FIG. 2 , showing the handles  20  positioned corresponding to the latches  18  unhooked, and the doors  12   a  and  12   b  closed is shown in  FIG. 3B , and a top view taken along line  3 - 3  of  FIG. 2 , showing the handles  20  positioned corresponding to the latches  18  unhooked, and the doors  12   a  and  12   b  open is shown in  FIG. 3C . The handles  20  are rotated along a second arc  30  to rotate the vertical bars  16  (see  FIG. 2 ) between the hooked and unhooked positions. Unfortunately, the handles  20  are fairly short to fit in the allowable space. As containers age, become corroded, or damaged, the vertical bars  16  and/or latch  18  often become difficult to operate. Truck drivers are known to use hammers, and other potentially damaging objects, to rotate the handles  20 . Further, soiled, icy, or wet handles may be very difficult to grasp. No tool is presently available to easily overcome these difficulties.  
         [0031]     A side view of a door handle extender  40  according to the present invention is shown in  FIG. 4A , a top view of the door handle extender  40  is shown in  FIG. 4B , and an end view of the door handle extender  40  is shown in  FIG. 4C . An engaging portion  48 , a center portion  50 , and a grasping portion  52  of the door handle extender  40  are shown in  FIG. 5 . The door handle extender  40  has an overall length L, and an overall height H. The length L is preferably between approximately 18 inches and approximately 28 inches, and the length L is more preferably is approximately 20.75 inches, and the height H is preferably between approximately three inches and approximately seven inches, and more preferably approximately to five inches. The engaging portion  48  preferably includes a substantially straight section with a length L M  running to a first end  40   a  of the door handle extender  40 , which length L M  is preferably approximately ½ inches to approximately three inches, and more preferably approximately two inch. The grasping portion  52  preferably comprises a substantially straight length L G  running to a second end  40   b  of the door handle extender  40 , wherein the length L G  is preferably between approximately 10 inches and approximately 20 inches, and more preferably approximately 11.5 inches. The engaging portion  48  need only be substantially straight sufficiently to allow the engaging portion to slide over the handle  20 . The grasping portion need only be substantially straight sufficiently to avoid adjacent vertical bars and handles, and to provide space grasping the door handle extender  40 . The door handle extender  40  may be made from any suitably strong material, for example, steel, galvanized steel, stainless steel, aluminum, and is preferably made from a commonly available steel pipe or tuning, and is more preferably made from schedule  40  or schedule  80  steel pipe, and most preferably from schedule  40  steel pipe. The door handle extender  40  is further preferably made from ¾ inch, one inch, or 1¼ inch steel pipe, and is more preferably made from one inch steel pipe. The portions  48 ,  50 , and  52  are preferably straight within the normal tolerances of schedule  40  steel pipe.  
         [0032]     A first bend  54  between the engaging portion  48  and the center portion  50  is preferably between approximately 15 degrees and approximately 60 degrees, and is more preferably an approximately 35 degree bend, and has an inside radius of approximately 0.25 inches. A second bend  56  between the center portion  50  and the grasping portion  52  is preferably between approximately 15 degrees and approximately 60 degrees, and is more preferably an approximately 35 degree bend, and has an inside radius of approximately 0.25 inches. The bends  54  and  56  are preferably similar angles and the grasping portion  52  is preferably parallel to the engaging portion  48 . The door handle extender  40  is offset to avoid hitting an adjacent handle or vertical bar, and to provide space between the door  12   a  or  12   b  and the door handle extender  40  to allow a solid grip. The length of the door handle extender  40  provides sufficient leverage to rotate the handles  20 , without being so long as to be a nuisance in the truck cab, trunk, or similar storage location.  
         [0033]     The engaging portion  48  includes a mouth  42  for cooperating with the handle  20 . The mouth has an inside width W M  and an inside height H M . The width W M  is preferably between approximately 0.35 inches and approximately 1.5 inches and is more preferably approximately 1.29 inches, and the height H M  is preferably between approximately 0.35 inches and approximately one inch and is more preferably approximately 0.69 inches. The mouth  42  has inside radii R M  of preferably between approximately 0.05 inches and approximately 0.75 inches and is more preferably approximately 0.125 inches. The inside dimensions of the mouth  42  are important to prevent the door handle extender  40  from rotating on the handle  20  during use, while permitting the mouth  42  to fit over common handles  20 . The shape of the mouth is preferably formed from common schedule  40  steel pipe using a form fitter hydraulic press, for example, a pinch press. If the door handle extender  40  can rotate excessively, a drivers knuckles may hit the door  12   a  or  12   b  when hooking the latches  18 . A grip  44  preferably resides on the grasping portion  52  to provide more comfortable use of the door handle extender  40 . The grip  44  preferably comprises a textured vinyl over a soft vinyl, for example a soft-tex vinyl grip. The grip may be made with a double dip process and have a rounded end, resulting in a inner smooth vinyl layer and a textured outer vinyl layer. The grip is preferably approximately six inches long and approximately 1.36 inches in outside diameter.  
         [0034]     The door handle extender  40  further includes a fifthwheel handle notch  41  for pulling a fifthwheel handle. The notch  41  is angled back at approximately 35 degrees, is approximately ½ inches wide, and is approximately ½ inches deep.  
         [0035]     Loops (or “D” rings)  38  attached to the door handle extender  40  are shown in  FIG. 1A , and in  FIG. 4D  a cross-sectional view taken along line  4 D- 4 D of  FIG. 4A . The loops  38  may be attached to the door handle extender  40  for attaching a lanyard to carried about a wrist to improve safety.  
         [0036]     A rear view of the trailer door  12   b  with the door handle extender  40  engaging a handle  20  is shown in  FIG. 6 , a top view of the door handle extender  40  engaging a handle  20  with the handle  20  in the hooked position is shown in  FIG. 7A , and a top view of the door handle extender  40  engaging the handle  20  with the handle  20  in the unhooked position is shown in  FIG. 7B . The door handle extender  40  thus avoids the adjacent vertical bar  18  and handle  20 , and provides space for a two handed side by side grasp of the grasping portion  52 .  
         [0037]     A top view of a tractor  26  including a trailer plate (also called a fifthwheel)  28  is shown in  FIG. 8A , and a top view of the tractor  26  showing the door handle extender  40  engaging a fifthwheel handle  48  attached to the trailer plate  28  is shown in  FIG. 8B . The handle  48  releases jaws  50  which retain a trailer kingpin in place in the fifthwheel  28 . A large amount of grease is applied to the trailer plate  28  to facilitate engagement of the trailer  24  with the tractor  26  and articulation of the tractor/trailer. As a result of the proximity of the fifthwheel handle  48  to the trailer plate  28  and to a bottom nose section of the trailer, it is difficult to pull the fifthwheel handle  48  without become soiled by grease, road grit, etc. Using the door handle extender  40  enables simple, safe, and clean actuation of the fifthwheel handle  48 .  
         [0038]     The door handle extender  40  is preferredly made from common schedule  40  steel/iron pipe or tubing, seamless or welded. The finished door handle extender  40  preferably includes a rust preventative or inhibitive coating because of expected use in harbor areas and ocean enviroments. More particularly, the door handle extender  40  is preferably finished by chemically cleaning, sand blasting, priming, and painting by powder coating. The priming is preferably with a rust preventive primer.  
         [0039]     A method according to the present invention is described in  FIG. 9 . The method includes sliding a mouth of a door handle extender over a container door handle at step  60 , pulling the handle extender up to disengage the handle from a handle holder at step  62 , pulling the handle extender away from the door to rotate a vertical bar of the door at step  64 , sliding the handle extender off of the handle at step  66 , using the handle extender to rotate any remaining unrotated vertical bars at step  68 , and opening the container door at step  70 .  
         [0040]     While the invention herein disclosed has been described by means of specific embodiments and applications thereof, numerous modifications and variations could be made thereto by those skilled in the art without departing from the scope of the invention set forth in the claims.

Summary:
A door handle extender for a shipping-container, a dry freight unit, or a refrigerator unit. The door handle is attached to a vertical locking bar which is rotated to hook and to unhook latches residing at the top and bottom of the shipping-container door. The latches engage locking housings attached to the shipping-container to lock the doors. The door handle extender comprises an offset arm with a grasping portion at one end and an engaging portion at an opposite end. The engaging portion includes a door handle mouth for sliding over the door handle. The door handle mouth is sized and shaped to nonrotatingly engage the door handle. The grasping portion includes a soft covering and allows a two handed grip. The door handle extender is offset to clear an adjacent vertical bar and may further include a notch to engage a fifthwheel release handle to facilitate releasing a trailer.