Patent Publication Number: US-8967637-B2

Title: Tail wheel transporter

Description:
RELATED APPLICATIONS 
     This application is a continuation-in-part of U.S. patent application Ser. No. 13/169,680 filed Jun. 27, 2011 (issued as U.S. Pat. No. 8,336,900) by the same inventor which, in turn, claims the benefit of U.S. Provisional Patent Application 61/362,342 filed Jul. 8, 2010 by the same inventor. 
    
    
     FIELD OF THE INVENTION 
     This invention relates to a device for moving an aircraft having tail wheel while the aircraft is on the ground. The invention further relates to a lever jack on a dolly. 
     BACKGROUND 
     In general aviation, it is sometimes necessary to move aircraft on an aircraft hanger floor or on a tarmac without powering up the aircraft engine. For aircraft equipped with tail wheels (hereinafter “tail wheel aircraft”), it is generally preferred to move the aircraft by grasping the tail and then pushing, pulling, and/or turning the aircraft. Depending on the weight and design of the tail wheel aircraft, this may be a strenuous task. The tail of a tail wheel aircraft is the location of several of the aircraft&#39;s control surfaces. Pushing or pulling of these control surfaces for the purpose of ground movement is generally not recommended and could cause damage that could result in loss of control of the aircraft while in flight. 
     US Patent Application Publication Number 20060056949 A1 published 2006 Mar. 16 on behalf of Eckert for a TRANSPORT VEHICLE FOR AIRCRAFT discloses a tricycle wheel arrangement on a bifurcated chassis that receives the aircraft wheel between the axles. The two drive wheels (or tracks) are independently driven for steering. As a motorized system, Eckert&#39;s invention is very heavy, very complex, and expensive. 
     U.S. Pat. No. 5,071,151 issued 1991 Dec. 10 to Irwin for a TAIL WHEEL AIRCRAFT DOLLY discloses a two-wheeled dolly with two-arms, positioned on a handle, for receiving the tail wheel from the side. The long handle from the axle is used to lift and balance the tail of the aircraft during movement. Constant manual force must be applied to the handle to maintain lift and balance. 
     U.S. Pat. No. 1,902,834 issued on 1933 Mar. 28 to Cohen-Venezian for a TAIL-SUPPORTING TRUCK FOR AEROPLANES discloses the use of two wheels on a single axle with a cup or support for receiving a tail wheel above the axle. An elongated handle coupled to the axle requires constant force to be manually applied to maintain balance during operation. 
     U.S. Pat. No. 5,511,926 issued 1996 Apr. 30 to Iles for MOVEMENT OF AIRCRAFT discloses a two-axle bifurcated chassis on a self-propelled dolly. Two drive wheels are on opposite sides of the bifurcated chassis and a closely set pair of wheels is pivotably mounted to the chassis and directed by manual operation of an elongated handle. The tail wheel to be lifted is engaged between the bifurcated chassis members. Being motorized and battery powered, Iles&#39; invention is heavy and expensive. 
     U.S. Pat. No. 6,636,709 B1 issued 2003 Mar. 25 to McVaugh for a SMALL AIRCRAFT POWER TUG discloses a two-wheel assembly with arms for engaging the nose wheel axle and a drive wheel. The drive wheel is powered by a power drill through a drive train in the elongated handle. McVaugh does not lift the nose wheel, but can tilt the dolly to a tricycle configuration when not engaged with an aircraft for free wheeling. 
     U.S. Pat. No. 4,854,803 issued on 1989 Aug. 8 to Coccaro for an APPARATUS AND METHOD FOR JACKING AND DOLLYING AN AFFIXED VEHICLE WHEEL ASSEMBLY discloses a four-castered U-shaped chassis with an elongated handle. The casters are attached on chassis members with dual-angled ends. The U-shaped chassis engages a wheel from the side. 
     Therefore, a need exists for a tail wheel transporter that is lightweight and does not require the application of constant manual force to maintain lift or balance. A need also exists for a tail wheel transporter that is easy to steer. A need also exists for a tail wheel transporter that is adaptable to tail wheels of various widths. A need exists for a tail wheel transporter that can be manufactured in various sizes and strengths for retaining tail wheels and aircraft of various masses. A need also exists for a tail wheel transporter that can be adapted to lift tail wheels of various diameters. A need also exists for a tail wheel transporter that is inexpensive to manufacture and ship. A need also exists for a tail wheel transporter that allows ground transport of an aircraft without touching or damaging the control surfaces of the aircraft. 
     OBJECTS AND FEATURES OF THE INVENTION 
     A primary object and feature of the present invention is to overcome the above-mentioned problems and fulfill the above-mentioned needs. 
     Another object and feature of the present invention is to provide a tail wheel transporter that is lightweight and does not require the application of constant manual force to maintain lift or balance. Another object and feature of the present invention is to provide a tail wheel transporter that is easy to steer. Another object and feature of the present invention is to provide a tail wheel transporter that is adaptable to tail wheels of various widths. Another object and feature of the present invention is to provide a a tail wheel transporter that can be manufactured in various sizes and strengths for retaining tail wheels and aircraft of various masses. Another object and feature of the present invention is to provide a tail wheel transporter that can be adapted to lift tail wheels of various diameters. Another object and feature of the present invention is to provide a tail wheel transporter that is inexpensive to manufacture and ship. 
     It is an additional primary object and feature of the present invention to provide a tail wheel transporter that is safe, inexpensive, easy to clean, and handy. Another object and feature of the present invention is to provide a tail wheel transporter that allows ground transport of an aircraft without touching or damaging the control surfaces of the aircraft. Other objects and features of this invention will become apparent with reference to the following descriptions. 
     SUMMARY OF THE INVENTION 
     In accordance with a preferred embodiment hereof, the present invention provides a tail wheel transporter including: a tricycle carriage further including a main frame extending off-centered from a rear axle to a front caster attachment plate; a pivot bar pivotably mounted to a side of the main frame proximate a centerline orthogonal to the rear axle; a lifting foot pivotably coupled to the pivot bar and extending horizontally, when in a quiescent state, from the pivot bar to a point behind the front caster attachment plate, where the main frame, the pivot bar, and the lifting foot are three bars of a four bar mechanism; a lifting arm extending from the pivot bar; a towing arm extending from the main frame; and a latch operable to releasably couple the lifting arm to the towing arm when the lifting arm is in a lifted position. The tail wheel transporter, further including a biasing mechanism operable to bias the lifting foot toward a non-lifted position. The tail wheel transporter, further including a fourth bar of the four bar mechanism pivotably coupled on first and second ends to the main frame and the lifting foot, respectively. The tail wheel transporter, where the lifting foot further includes a first stud extending sideways from the lifting foot across the centerline. The tail wheel transporter, where the first stud further includes an axle for one pivotable coupling of the four bar mechanism. The tail wheel transporter, where the lifting foot further includes a second stud extending sideways from the lifting foot across the centerline and having an adjustable position on the lifting foot. The tail wheel transporter, where the adjustable position includes a slider mechanism operable to adjust the position of the second stud at various positions along a slot of the slider mechanism. The tail wheel transporter, where the slider mechanism includes: the slot along at least a portion of a centerline-proximal side of the lifting foot; an axial channel within the lifting foot; a slider block operable to slide within the axial channel, where the slider block includes: a first threaded bore alignable to the slot and operable to receive a threaded end of the second stud; and a second threaded bore alignable to the slot and operable to receive a set screw. The tail wheel transporter, where the tail wheel transporter is configured to receive the force of a wheel to be transported on the first and second studs of the lifting foot at a vertical position below the rear axle when the lifting foot is in a lifted position. The tail wheel transporter, where the four bar mechanism includes a parallelogram configuration. The tail wheel transporter, where the tricycle carriage includes a bifurcated front wheel. The tail wheel transporter, where the lifting arm includes first and second releasable and re-connectable sections. The tail wheel transporter, where the towing arm includes first and second releasable and re-connectable sections. 
     A tail wheel transporter including: a tricycle carriage further including a main frame extending off-centered from a rear axle to a front caster attachment plate and a bifurcated front wheel; a pivot bar pivotably mounted to a side of the main frame proximate a centerline orthogonal to the rear axle; a lifting foot pivotably coupled to the pivot bar and extending horizontally, when in a quiescent state, from the pivot bar to a point behind the front caster attachment plate, where the main frame, the lifting foot, and the pivot bar comprise three bars of a four bar mechanism; a lifting arm extending from the pivot bar; a towing arm extending from the main beam; a latch operable to releasably couple the lifting arm to the towing arm when the lifting arm is in a lifted position; the lifting foot including a first stud extending sideways across the centerline from the lifting foot; the lifting foot including a second stud extending sideways from the lifting foot across the centerline and having an adjustable position on the lifting foot; and where the tail wheel transporter is configured to receive the force of a wheel to be transported on the first and second studs of the lifting foot at a vertical position below the rear axle when the lifting foot is in a lifted position. The tail wheel transporter, where the adjustable position includes a plurality of threaded bores in the lifting foot, where each bore of the plurality of threaded bores is operable to receive a threaded end of the second stud; and/or a slider mechanism operable to adjust the position of the second stud at various positions along a slot of the slider mechanism. The tail wheel transporter, where the slider mechanism includes: the slot along at least a portion of a centerline-proximal side of the lifting foot; an axial channel within the lifting foot; a slider block operable to slide within the axial channel, where the slider block includes: a first threaded bore alignable to the slot and operable to receive a threaded end of the second stud; and a second threaded bore alignable to the slot and operable to receive a set screw. The tail wheel transporter, where the four bar mechanism further includes a fourth bar pivotably coupled at a first end to the main frame and pivotably coupled at a second end to a front end of the lifting foot. 
     A tail wheel transporter including: a tricycle carriage further including a main frame extending off-centered from a rear axle to a front caster attachment plate; a pivot bar pivotably mounted to a side of the main frame proximate a centerline orthogonal to the rear axle; a lifting foot pivotably coupled to the pivot bar as two bars of a four-bar mechanism; a biasing mechanism operable to bias the lifting foot toward a non-lifted position; a lifting arm extending from the pivot bar; a towing arm extending from the main beam; a latch operable to releasably couple the lifting arm to the towing arm when the lifting arm is in a lifted position; where the lifting foot includes a first stud extending sideways from the lifting foot across the centerline; where the lifting foot further includes a second stud extending sideways from the lifting foot across the centerline and having an adjustable position on the lifting foot; and where the tail wheel transporter is configured to receive the force of a wheel to be transported on the first and second studs of the lifting foot at a vertical position below the rear axle when the lifting foot is in a lifted position. The tail wheel transporter, where the adjustable position includes a plurality of threaded bores in the lifting foot, where each bore of the plurality of threaded bores is operable to receive a threaded end of the second stud; and/or a slider mechanism operable to adjust the position of the second stud at various positions along a slot of the slider mechanism; where the slider mechanism includes: the slot along at least a portion of a centerline-proximal side of the lifting foot; an axial channel within the lifting foot; a slider block operable to slide within the axial channel, where the slider block includes: a first threaded bore alignable to the slot and operable to receive a threaded end of the second stud; and a second threaded bore alignable to the slot and operable to receive a set screw. The tail wheel transporter, where the tricycle carriage includes a bifurcated front wheel. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       The above and other objects and advantages of the present invention will become more apparent from the following description taken in conjunction with the following drawings in which: 
         FIG. 1  is a side elevation view illustrating an exemplary tail wheel transporter, according to a preferred embodiment of the present invention; 
         FIG. 2  is a front-left perspective view illustrating the exemplary tail wheel transporter, according to the preferred embodiment of  FIG. 1 ; 
         FIG. 3  is a rear-left perspective view illustrating the exemplary tail wheel transporter, according to the preferred embodiment of  FIG. 1 ; 
         FIG. 4  is a top-left-rear perspective view illustrating the exemplary tail wheel transporter, according to the preferred embodiment of  FIG. 1 ; 
         FIG. 5  is a front-right perspective view illustrating the exemplary tail wheel transporter, according to the preferred embodiment of  FIG. 1 ; 
         FIG. 6  is a top plan view illustrating the exemplary tail wheel transporter, according to the preferred embodiment of  FIG. 1 ; 
         FIG. 7  is a front elevation view illustrating the exemplary tail wheel transporter, according to the preferred embodiment of  FIG. 1 ; 
         FIG. 8  is rear elevation view illustrating the exemplary tail wheel transporter, according to the preferred embodiment of  FIG. 1 ; 
         FIG. 9  is a left-side elevation view illustrating the exemplary tail wheel transporter, according to the preferred embodiment of  FIG. 1 ; 
         FIG. 10  is a front-left perspective view illustrating an exemplary tail wheel transporter, according to a second preferred embodiment of the present invention; 
         FIG. 11  is a front-right perspective view illustrating an exemplary an adjustable stud for an exemplary tail wheel transporter, according to a second preferred embodiment of the present invention as shown in  FIG. 10 ; 
         FIG. 12  is a rear-right perspective view illustrating an exemplary an adjustable stud for an exemplary tail wheel transporter, according to a second preferred embodiment of the present invention as shown in  FIG. 10 ; 
         FIG. 13  is a side elevation view illustrating an additional exemplary stud support with an adjustable stud for an exemplary tail wheel transporter, according to a preferred embodiment of the present invention; 
         FIG. 14  is a side elevation view illustrating an additional exemplary embodiment of a tail wheel transporter, according to a preferred embodiment of the present invention; 
         FIG. 15  is a front-left perspective view illustrating the exemplary embodiment for the exemplary tail wheel transporter of  FIG. 14 , according to a second preferred embodiment of the present invention; 
         FIG. 16  is a side elevation view illustrating an additional exemplary embodiment of a tail wheel transporter, according to a preferred embodiment of the present invention; and 
         FIG. 17  is a front-left perspective view illustrating the exemplary embodiment for the exemplary tail wheel transporter of  FIG. 16 , according to a second preferred embodiment of the present invention. 
     
    
    
     DETAILED DESCRIPTION OF THE BEST MODES AND PREFERRED EMBODIMENTS OF THE INVENTION 
       FIG. 1  is a side elevation view illustrating an exemplary tail wheel transporter  100 , according to a preferred embodiment of the present invention. Main frame  102  includes horizontal frame member  104  and angled frame extension  106 . Horizontal frame member  104  supports elongated handle  146 , axle  202  (see  FIG. 2 ), and pivot  132 . Angled frame extension  106  supports caster attachment plate  108 . Main frame  102  is preferably made of substantially rigid material, such as steel or aluminum. In various embodiments, various other materials may be used. For example, in an embodiment where weight is at a premium, such as a tail wheel transporter  100  designed to be transported in an aircraft, Boron-epoxy composite may be used. Those of skill in the art, illuminated by the present disclosure, will be aware of materials that are appropriate for various unique applications. 
     Caster attachment plate  108  is preferably welded to angled extension  106 . In an alternate embodiment, main frame  102  and caster attachment plate  108  may be formed as a single piece. Caster  118  includes caster base plate  112 , caster support arms  114  (one of two shown) and caster wheel  116 . Caster  118  may be a commercial-off-the-shelf (COTS) product or may be specially made. Caster base plate  112  is releasably attached to caster support plate  108 , illustrated here as using bolts  110  (one of four labeled, two visible). In various other embodiments, other means of attachment, such as clamps or various fasteners, may be used. In an alternate embodiment, caster base plate  112  may be permanently fixed to caster support plate  108 . Caster wheel  116  and caster support arms  114  are free to swivel together about an axis through the caster base plate  112 . In various other embodiments, various types of casters may be used. 
     Elongated handle  146  is made of substantially rigid material, and is preferably welded to horizontal frame member  104 . In an alternate embodiment, elongated handle  146  may be releasably attached to horizontal frame member  104 . In yet another alternate embodiment, elongated handle  146  may be made of a composite material. Elongated handle  146  supports latch  148 , crossbar  210  (See  FIG. 2 ), and handles  150  and  250  (See  FIG. 2 ). Latch  148  is rotatable to latch lifting arm  138  when lifting arm  138  is moved proximate elongated handle  146 . Latch  148  is preferably made of metal but may be made of plastic in an alternate embodiment. Handles  150  and  250  improve the operator&#39;s grip on the crossbar  210  on the elongated handle  146 . Handles  150  and  250  may be COTS bicycle hand grips, for example. Elongated handle  146  may be made in releasable and re-connectable sections  1044  and  1046  (See  FIG. 10 ) for a portable embodiment. 
     Rear wheels  144  and  244  (See  FIG. 2 ) preferably include pneumatic tires and rotate with or on axle  202 . Materials for rear wheels  144  and  244  may vary, depending on the application for various embodiments. For example, a studded tire may be useful for Arctic applications, while a tire with high heat resistance may be desired for Arizona tarmacs. Those of skill in the art, illuminated by the present disclosure, will be aware of tire material requirements for various operational environments. The diameter of rear wheels  144  and  244  and the vertical extent of caster  118  are selected to maintain horizontal frame member  104  in a substantially horizontal orientation and to provide ground clearance to lifting foot  120 . Preferably, when the lifting foot  120  is in the lifted position, the point at which the force exerted by the weight on the tail wheel  902  is below axle  202 . More preferably, when the lifting foot  120  is in the lifted position, the point at which the force exerted by the weight on the tail wheel  902  is below axle  202  and below caster axle  160 . Rear wheels  144  and  244 , as well as caster  118 , axle  202 , caster support plate  108 , and the main frame  102 , form a tricycle carriage. 
     Lifting foot  120  includes stud support  122  rigidly attached to pivot bar  134 . Preferably, stud support  122  and pivot bar  134  are made as one piece. Preferably, stud support  122  has an axial channel  123  (See  FIGS. 11-13 ). Stud support  122  supports stud  124 , stud  128 , attachment means for spring  136 , holes  125  and  126  for a moveable stud  227  (See  FIG. 2 ). Holes  125  and  126  are preferably threaded bores  125  and  126 , the moveable stud  227  preferably has an end with complimentary threads to threaded bores  125  and  126 . In alternate embodiments, other means for releasably attaching moveable stud  227  may be used. The studs  124  and  128  engage the aircraft tail wheel  902  (see  FIG. 9 ) from the side and exert force on the tail wheel  902  when the tail wheel  902  is lifted. The holes  125  and  126  allow the moveable stud  227  to be placed to adjust for tail wheel  902  (See  FIG. 9 ) size. Tire cradle  130  is rigidly attached to fixed stud  128  and operates to prevent the tail wheel  902  from rolling off the back of fixed stud  128 . Tire cradle  130  may be of any shape and size operable to prevent the tail wheel  902  from rolling off the back of fixed stud  128 . 
     Pivot bar  134  receives and rotates upon pivot  132 , responsive to movement of lifting arm  138 . Lifting arm  138  includes lifting beam  140  and handle  142 . Beam  140  makes a 10° angle α with pivot bar  134 , and handle  142  makes a 5° angle β with beam  140 , as shown. The length of beam  140  and handle  142 , as well as the placement of latch  148 , are coordinated such that handle  142  may be latched in the lifted position. Angles α and β depend, in part, on the angle that elongated handle  146  makes with horizontal frame member  104  and the distance between the point of attachment of elongated handle  146  to horizontal frame member  104  and the pivot  132 . In various additional embodiments, the angles α and β may vary with such factors, and α and/or β may be zero in some embodiments. 
     The tail wheel transporter  100  is shown in its quiescent state, as it is prior to lifting a tail wheel  902 . In operation, a tail wheel  902  is engaged from the side on studs  124  and  128 , or perhaps a moveable stud  227 , and lifting arm  138  is manually pulled toward the elongated handle  146  and latched to elongated handle  146  using latch  148 . The load is thus received between the front caster  118  and the rear wheel  144 , and no additional manual force is required to maintain lift or balance while moving aircraft  900  (see  FIG. 9 ). 
       FIG. 2  is a front-left perspective view illustrating the exemplary tail wheel transporter  100 , according to the preferred embodiment of  FIG. 1 . Tail wheel transporter  100  is shown in its quiescent state. Axle  202  supports axle attachment  204  for spring  136 , rear wheel  144 , rear wheel  244 , and main frame  102 . Spring  136  biases the pivot bar  134 , lifting foot  120 , and lifting arm  138  towards the quiescent state, as shown. Moveable stud  227  is shown in position to assist with a lift. Latch pivot  208  is shown and latch  148  may be more clearly understood from this illustration. Elongated handle  146  terminates in a cross bar  210  that supports handles  150  and  250 . Support flange  206  supports elongated handle  146  relative to horizontal frame member  104 . The offset of main frame  102  on axle  202  may be more clearly understood by reference to  FIG. 2 . Note that both the main frame  102  and the lifting foot  120  are offset from the center of axle  202 . 
       FIG. 3  is a rear-left perspective view illustrating the exemplary tail wheel transporter  100 , according to the preferred embodiment of  FIG. 1 . The tail wheel transporter  100  is shown in its lifted state, with lifting arm  138  rotated back to elongated handle  146  and latched to elongated handle  146  by the manual pivoting of latch  148  about latch pivot  208 . Lifting foot  120  is raised by the lever action of lifting handle  138  and pivot bar  134 . Lifting arm stop  302  is illustrated as a flange attached to main frame  102  and a bolt through a threaded bore in the flange that can be turned to adjust the point at which the spring-biased downward travel of the lifting arm  138  stops. Bore  304 , preferably a threaded bore, is for storage of moveable stud  227  when it is not in use. 
       FIG. 4  is a top-left-rear perspective view illustrating the exemplary tail wheel transporter  100 , according to the preferred embodiment of  FIG. 1 . The tail wheel transporter  100  is shown in its quiescent state. The pivot arm  134  is in contact with the lifting arm stop  302 . 
       FIG. 5  is a front-right perspective view illustrating the exemplary tail wheel transporter  100 , according to the preferred embodiment of  FIG. 1 . The tail wheel transporter  100  is shown in its quiescent state. 
       FIG. 6  is a top plan view illustrating the exemplary tail wheel transporter  100 , according to the preferred embodiment of  FIG. 1 . The tail wheel transporter  100  is shown in its quiescent state. This view emphasizes that both the main frame  102  with elongated handle  146  and lifting foot  120 , pivot bar  134 , and lifting handle  138  are offset from the centerline  602  of axle  202 . Studs  124 ,  227 , and  128 , as well as tire cradle  130  all extend through the centerline  602 , meaning that the weight exerted by the tail wheel  902  is approximately centered side-to-side. 
       FIG. 7  is a front elevation view illustrating the exemplary tail wheel transporter  100 , according to the preferred embodiment of  FIG. 1 . The tail wheel transporter  100  is shown in its quiescent state. 
       FIG. 8  is rear elevation view illustrating the exemplary tail wheel transporter  100 , according to the preferred embodiment of  FIG. 1 . The tail wheel transporter  100  is shown in its quiescent state. 
       FIG. 9  is a left-side elevation view illustrating the exemplary tail wheel transporter  100 , according to the preferred embodiment of  FIG. 1 . The tail wheel transporter  100  is shown in its lifted state, with tail wheel  902  of aircraft  900  supported by fixed stud  128  and moveable stud  227 . Latch  148  is latched, and the load is received between front and rear axles, making the lifted state a stable state. 
     Those of skill in the art, illuminated by the present disclosure, will appreciate that, while the example provided operates manually, the invention may also be implemented mechanically or hydraulically by merely replacing the manual force on the lifting arm  138  with a mechanical or hydraulic force. The force may be powered by electrical or other means. Likewise, embodiments made lightweight and more portable or more easily shippable are also within the scope of the present invention. Various embodiments of the invention may be equipped with a motorized system to propel the tail wheel transporter  100 . 
       FIG. 10  is a front-left perspective view illustrating an exemplary tail wheel transporter  1000 , according to a second preferred embodiment of the present invention. Tail wheel transporter  1000  has a lifting arm  1038  for which the angles α and β are zero. Lifting arm  1038  has first and second releasable and re-connectable sections  1042  and  1044  releasably joined with a telescoping rod and pin assembly  1050 , allowing for disassembly for shipping. Towing arm  1040  has first and second releasable and re-connectable towing arm sections  1046  and  1048  releasably joined with a telescoping rod and pin assembly  1052 , allowing for disassembly for shipping. Towing arm section  1048  is releasably affixed to main frame end member  1066 , preferably in alignment with horizontal frame member  1004 . Rear axle  202  extends through main frame  1004 . Main frame  1002  includes horizontal frame member  1004  and angled frame extension  106 . Horizontal frame member  1004  supports releasably attachable plate  1066  which is welded to the bottom end of second section  1048  of towing arm  1040  and bolted to main frame  1004 . 
     Lifting foot  1020  includes stud support  1022  rigidly attached to pivot bar  134 . Preferably, stud support  1022  and pivot bar  134  are made as one piece. Stud support  1022  includes stud  128 , a slot  1028  from which protrudes stud  1027 , a slider mechanism  1100  (See  FIG. 11 ), and attachment means for spring  136 . Attachment means for spring  136  may be a loop or other coupling for receiving or engaging and end portion of spring  136 . The moveable stud  1027  preferably has an end with complimentary threads to the threaded bore  1106  (see  FIG. 11 ) in the slider mechanism. 
     Surfaces  1029  and  1032  are preferably high-friction surfaces. For example, surfaces  1029  and  1032  may be covered with SAFETY-WALK™ adhesive tread made by the 3M Company of St. Paul, Minn. 
       FIG. 11  is a front-right perspective view illustrating an exemplary adjustable stud  1027  for an exemplary tail wheel transporter  1000 , according to a second preferred embodiment of the present invention as shown in  FIG. 10 . Stud support  1022  is hollow and has a slot  1028  on one side through which stud  1027  protrudes. Slider block  1102  moves slidingly within hollow stud support  1022 . Slider block  1102  has a first threaded bore  1106  into which complimentary threads at a first end of stud  1027  are threaded. A second end of stud  1027  has a driver receiver  1108  (illustrated as a screwdriver slot) for tightening stud  1027  in place. Slider block  1102  has a second threaded bore  1104  into which complimentary threads of a set screw  1110  are threaded. Set screw  1110  is preferably an Allen-head screw, but other driver receivers  1112 , including unique driver receivers  1112 , are within the scope of the invention. The slider mechanism  1100  includes the slot  1028 , slider block  1102 , set screw  1110 , and stud  1027 . Slider mechanism  1100  permits adjustment to any size tail wheel  902 , and is not limited to accommodating discrete popular sizes. An Allen wrench or similar driver may be provided by the consumer or, in an alternate embodiment, may be supplied with tail wheel transporter  1000 . 
       FIG. 12  is a rear-right perspective view illustrating an exemplary adjustable stud  1027  for an exemplary tail wheel transporter  1000 , according to a second preferred embodiment of the present invention as shown in  FIG. 10 . Slider block  1102  is shown from the rear with the threads of stud  1027  protruding through the slider block  1102  and set screw  1110  also protruding through slider block  1102 . This configuration, when achieved inside hollow stud support  1022 , locks the stud  1027  and slider block  1102  from sliding within the hollow stud support  1022 . Slider mechanism  1100  allows locking in various analog positions along the slot  1028  to accommodate tail wheels  902  of a wide range of sizes. 
       FIG. 13  is a side elevation view illustrating an alternate exemplary stud support  1322  with an adjustable stud  1027  for an exemplary tail wheel transporter, according to a preferred embodiment of the present invention. Stud support  1322  differs from stud support  1022  of  FIG. 10  in that the outside corners  1306  (one of two labeled) and the inside corners  1304  (one of two labeled) of the stud support  1322  are rounded, whereas the stud support  1022  illustrated in  FIG. 10  does not have rounded corners. The difference illustrates that, in various alternate embodiments, various internal and external cross-sectional shapes may be used for stud support  1322 . Slider block  1302  is shown inside hollow stud support  1322  in the fully tightened position and is engaged by the threads of adjustable stud  1027  to assist in locking the slider block  1302  in place Slider block  1302  has conformally shaped corners  1308  (one of two labeled) that are received by inside rounded corners  1304  of stud support  1322 . In various alternate embodiments, slider block  1302  has a shape at least partially conformal to the inside cross-sectional shape of the stud support  1322 . 
       FIG. 14  is a side elevation view illustrating an additional exemplary embodiment of a tail wheel transporter  1400 , according to another preferred embodiment of the present invention. Tail wheel transporter  1400  is similar to tail wheel transporter  100  except tail wheel transporter  1400  uses a four-bar mechanism  104 ,  1434 ,  1422 , and  1450  to implement lifting foot  1420 . Pivot  1404  pivotably couples frame member  104  to a top end of free bar  1450 . The bottom end of free bar  1450  is pivotably coupled (not visible in this view) to the forward end of stud support  1422 . The rear end of stud support  1422  is pivotably coupled to pivot bar  1434  by pivot  1430 . Pivot bar  1434  is pivotably coupled by pivot  132  to frame member  104 , thereby completing the four-bar mechanism. When handle  142  is moved to rotate pivot bar about pivot  132 , stud support  1422  moves upward with little or no tilting. Stud support  1422  supports one moveable stud  1424  that can be releasably fixed within slot  1426 , as described in detail in regard to  FIGS. 11-13 , and one fixed stud  1428  that also serves as an axle for pivot  1430 . Spring  136  attaches to the rear end of stud support  1422 . In operation, a tail wheel  1402  rests on studs  1424  and  1428 , is lifted or lowered by action of handle  142 , and may be transported, along with the vehicle it is connected to, by manual operation of elongated handle  146 . The remaining portions for tail wheel transporter  1400  are the same as tail wheel transporter  100 . 
       FIG. 15  is a front-left perspective view illustrating the exemplary embodiment for the exemplary tail wheel transporter  1400  of  FIG. 14 , according to another preferred embodiment of the present invention. Spacers  1452  may be used between frame member  104  and pivot bar  1434  to provide space for free bar  1450 . Fixed stud  1428  can be more clearly seen as the axle of pivot  1430 . Variations in the relative lengths of the four bar mechanism are within the scope of the invention. While the exemplary embodiments are manually operated, motorized embodiments are also within the scope of the invention. 
       FIG. 16  is a side elevation view illustrating an additional exemplary embodiment of a tail wheel transporter  1600 , according to a preferred embodiment of the present invention. Tail wheel transporter  1600  features the four bar mechanism  1604 ,  1450 ,  1422 , and  1434  as tail wheel transporter  1400 , but differs in having a low-profile front end  1602 . Low-profile front end  1602  includes a caster support plate  1608  fixed (preferably welded) to the top surface of frame member  1604  proximate the front end of the frame member  1604 . Caster support plate  1608  supports two casters  1618  (one visible in this view) each having a wheel  1616  and a pair (one visible in this view) of wheel support arms  1614  that are rotationally coupled to a caster mounting plate  1612 . The caster mounting plate  1612  is releasably fixed to the caster support plate  1608  with fasteners  1610 , illustrated as bolts  1610  (one of two labeled). Frame member  1604  is illustrated as straight, but the invention is not so limited. Caster support plate  1608  is illustrated as flat, but the invention is not so limited. The advantage of the low profile front end  1602  is that it allows the tail wheel transporter  1600  to be used in situations where there is low clearance under the aircraft or other vehicle. Using dual casters  1618  spreads the load, allowing smaller casters  1618  to be used. 
       FIG. 17  is a front-left perspective view illustrating the exemplary embodiment for the exemplary tail wheel transporter  1600  of  FIG. 16 , according to a second preferred embodiment of the present invention. All eight bolts  1610  (one of eight labeled) can be more clearly seen, along with dual casters  1618 . The illustrated shape of caster support plate  1608  is not a limitation of the invention. Tail wheel transporter  1600  still uses a tricycle carriage but has bifurcated front wheels  1618 . 
     While at least one exemplary embodiment has been presented in the foregoing detailed description, it should be appreciated that a vast number of variations exist. It should also be appreciated that the exemplary embodiment or exemplary embodiments are only examples, and are not intended to limit the scope, applicability, or configuration of the invention in any way. For example, and embodiment in which the rear wheels are casters and the front wheel is fixed is contemplated. Rather, the foregoing detailed description will provide those skilled in the art with a convenient road map for implementing the exemplary embodiment or exemplary embodiments. It should be understood that various changes can be made in the function and arrangement of elements without departing from the scope of the invention as set forth in the appended claims and the legal equivalents thereof.