Abstract:
The invention is a wheel jack having a cradle for a wheel. The cradle has a first surface and a second surface. The second surface is spaced from the first surface to form a wheel space. An actuator moves the first surface relative to the second surface along a horizontal direction to lift or lower the wheel in the cradle.

Description:
BACKGROUND OF THE INVENTION  
       [0001]     This invention relates to a tire jack for an aircraft wheel.  
         [0002]     An aircraft may require service of the wheels of its landing gear. Typically, a strut of the wheel is lifted by a jack operated by a technician. Another technician is then required to remove the tire from the lifted strut. These tires are very heavy and difficult to handle. If the tire is to be returned to the strut or a new tire placed on the strut, two technicians may be required to hold the tire to ensure correct alignment of the tire on the hub of the strut. It is therefore desirable to reduce the labor involved in this operation.  
         [0003]     In addition, existing tire dollies and jacks for aircraft have a high profile. This profile may make it difficult to maneuver the dolly or jack around the aircraft. A need therefore exists for a tire dolly or jack having a lower profile.  
       SUMMARY OF THE INVENTION  
       [0004]     The present invention comprises a wheel jack having a cradle for a wheel. The cradle has a first surface spaced from a second surface. The wheel is received in the space defined by the surfaces. An actuator, such as a hand crank, permits one surface to be driven horizontally closer or apart from the other surface. A wheel seated on these surfaces will be raised when the surfaces are brought together and lowered when the surfaces are brought apart. In this unique way, a wheel may be vertically lifted by horizontal movement of the surfaces supporting the wheel. This permits the invention to have a low profile.  
         [0005]     An actuator is linked to the first surface and the second surface. The actuator, such as a hand crank, permits one surface to be brought toward the other surface or moved away. In addition, each of the surfaces have rollers that permit the wheel to be rotated while in the cradle. This feature permits the wheel to be aligned with the hub of the aircraft strut with less labor.  
         [0006]     In addition, the cradle may be mounted to a set of wheels to permit the wheel jack to be easily maneuvered around the aircraft. One set of wheels may be mounted to the first surface while a second set of wheels may be mounted to the other surface. These wheels further assist one surface to be moved relative to the other in the horizontal direction to lift or lower the wheel. 
     
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       [0007]     The various features and advantages of this invention will become apparent to those skilled in the art from the following detailed description of the currently preferred embodiment. The drawings that accompany the detailed description can be briefly described as follows:  
         [0008]      FIG. 1  illustrates a perspective view of the inventive wheel jack, including wheel cradle, first surface and second surface, and actuator.  
         [0009]      FIG. 2  illustrates another perspective view of the inventive wheel jack of  FIG. 1 , showing without wheel the first surface and the second surface and actuator.  
         [0010]      FIG. 3  illustrates the inventive wheel jack with wheel supported by first surface and second surface of the wheel cradle.  
         [0011]      FIG. 4A  illustrates a cross-sectional view of the actuator of  FIGS. 1 and 2 .  
         [0012]      FIG. 4B  illustrates a cross-sectional view of the actuator of  FIG. 4A  with rod extended.  
         [0013]      FIG. 5  illustrates schematically the movement of first surface and second surface. 
     
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT  
       [0014]      FIG. 1  illustrates a perspective view of inventive wheel jack  14 . As shown, wheel jack  14  has wheel cradle  18  that receives wheel  10 . Wheel cradle  18  has first surface  26  and second surface  30  defining wheel space  22 . First surface  26  and second surface  30  permit rotation of wheel  10  on its axis, say along the direction of arrow H or the direction of arrow I as shown in  FIG. 1  and  FIG. 2 . This feature permits wheel  10  to be rotated in alignment with a hub of an aircraft strut (not pictured). As shown in the drawings, first surface  26  and second surface  30  may comprise a set of rollers  100  arranged along an incline, although each surface  26 ,  30  may employ a single roller to achieve the object of the invention.  
         [0015]     Actuator  30  is linked to drive first surface  26  relative to second surface  30 . By turning crank  46  in the direction of arrow K, second surface  30  may be moved in the horizontal direction of arrow C, i.e., away from first surface  26 . Alternatively, if crank  46  is turned in the direction of arrow J, as shown by  FIGS. 1 and 2 , second surface  26  may be moved in the direction of arrow D, i.e., towards first surface  30 . In this way, wheel space  22  may be decreased if second surface  30  is moved in the direction of arrow D or increased if moved in the direction of arrow C.  
         [0016]     As shown schematically by  FIG. 5 , movement of first surface  26  relative to second surface  30  permits wheel  10  located in wheel space  22  to be raised in the direction of arrow A or lowered in the direction of arrow B by horizontal movement of the first and second surfaces  26 ,  30  relative to one another. As seen in  FIG. 5 , wheel  10  is shown in the lifted position  66  when first surface  26  and second surface  30  are brought close to one another. Wheel  10  may be lowered by moving second surface  30  relative to first surface  26  in the direction of arrow C to the position designed by  30 ′ and shown schematically. At this point, wheel  10 ′ as shown by dashed lines is located on ground  74 . Wheel  10  may again be raised by moving second surface  30  closer to first surface  26  in the direction of arrow D. In this way, wheel  10  may be raised and lowered by horizontal movement of first surface  26  relative to second surface  30 .  
         [0017]      FIGS. 4A and 4B  illustrate actuator  34  of  FIGS. 1 and 2  in cross-section. As shown, actuator  34  has first tube  74 , which is formed together with first surface  26  and second tube  78 , which is formed as part of second surface  30 . Second tube  78  is slidably received within first tube  74  and moves relative to first tube  74  in the direction of arrow C or in the direction of arrow D. Movement is accomplished by turning crank  46 , which is fixed in rotation with threaded rod  38 .  
         [0018]     As mentioned earlier, turning crank  46  in the direction of arrow K moves second surface  30  away from first surface  26 . As shown in  FIG. 4B , crank  46  is turned in the direction of arrow K, which turns threaded rod  38  in the same direction. Threaded rod  38  is threadingly received by second tube  78 , which has inner threads as provided by two nuts  80  fixed to second tube  78 . Rotation of threaded rod  38  thereby causes second tube to extend outward from first tube  74 . In this way, wheel  10  may be lowered. Also, wheel  10  may be raised by rotating crank  46  in the direction of arrow J. Second tube  78  is brought to the position shown in  FIG. 4A . to prevent threaded rod  38  from extending outward in the direction of arrow D from first tube  70 , first tube  70  has stop  82 . Seated next to stop  82  is a Teflon thrust washer, washer  86 . Washer  86  provides a friction free surface upon which set screw  90  rotates. Set screw  90  is fixed to threaded rod  38 . Hence, rotation of crank  46  in the direction of arrow J moves second tube in the direction of arrow D. However, set screw  90  cannot rotate past stop  82  so thread rod  38  is prevented from moving in the same axial direction. Thrust bearing  94  is provided to allow crank  46  to rotate smoothly.  
         [0019]     To facilitate movement of first surface  26  relative to second surface  30 , each surface  26 ,  30  is provided with a set of wheels so that the surfaces may roll horizontally in the direction of arrow C and the direction of arrow D more easily. First surface  26  has second set of wheels  54  while second surface  30  has first set of wheels  50  as shown in  FIG. 2 . Wheels  50 ,  54  permit both surfaces  26 ,  30  to roll relative to one another. Wheels  50  and  54  may be caster wheels as shown in  FIG. 2  that permit wheel jack  14  to move horizontally in all directions so that wheel  10  may be transported very easily. In addition, as shown in  FIGS. 1 and 3 , wheel jack  14  may be provided with handle  62  to maneuver wheel jack  14 .  
         [0020]     The aforementioned description is exemplary rather that limiting. Many modifications and variations of the present invention are possible in light of the above teachings. The preferred embodiments of this invention have been disclosed. However, one of ordinary skill in the art would recognize that certain modifications would come within the scope of this invention. Hence, within the scope of the appended claims, the invention may be practiced otherwise than as specifically described. For this reason the following claims should be studied to determine the true scope and content of this invention.