Abstract:
An hydraulically extensible frame is coupled to the hitch portion of a trailer by a pivoting mount. The pivoting mount permits the frame to pivot between a generally vertical operative position and a generally horizontal stowed position. A foot member is secured to an end of the frame opposite the pivoting mount. The foot member engages the ground. An actuator is carried by the frame in a location adapted to be engaged by a foot of a human user when the frame is in the operative position. The actuator selectively extends the frame to raise the hitch portion in response to actuation by the foot of the user.

Description:
BACKGROUND OF THE INVENTION  
       [0001]     1. Field of the Invention  
         [0002]     The present invention relates to lifting mechanism or apparatus for use with wheeled trailers for lifting a portion of the trailer. More particularly, the present invention relates to such mechanisms or apparatus for lifting a portion of the trailer associated with a hitch to facilitate coupling the hitch and trailer to another vehicle.  
         [0003]     2. Summary of the Prior Art  
         [0004]     Trailers, as the name implies, typically are coupled to and trail behind a towing vehicle. A ball-and-socket type trailer hitch is conventionally employed to couple the two together. The hitch is usually a forward portion of the trailer referred to as the “tongue.” Such lifts are sometimes called “tongue jacks.” 
         [0005]     In many cases, the trailer is not coupled to the towing vehicle until the trailer is already loaded and quite heavy. The load exerted on the tongue and hitch portion of a trailer often is in excess of several hundred pounds. In such cases, attaching the trailer to the vehicle can be challenging because the hitch and tongue of the trailer generally must be raised above the level of the hitch on the vehicle, the two portions of the hitch aligned, and the tongue portion of the trailer lowered to fully engage the hitch. Accordingly, various lifting mechanisms have been associated with such trailers to facilitate the coupling operation. The lifting mechanism also supports the tongue and hitch (or forward) end of the trailer when it is uncoupled from the towing vehicle.  
         [0006]     Improvements have been made over time to the lifting mechanisms or apparatus used in conjunction with trailers. Such improvements include the use of electric motors and hydraulics to raise and lower the tongue and hitch of the trailer. Hydraulic lifts are smoother and often safer in operation than mechanical lifts, which can be subject to backlash. U.S. Pat. No. 3,273,858 to Coburn discloses a hand-operated hydraulic elevator for a trailer tongue. U.S. Pat. No. 4,911,460 to DePaula discloses a hand-operated mechanical arrangement. U.S. Pat. No. 5,011,119 to Harrington discloses another hand-operated hydraulic jack.  
         [0007]     A typical consumer use for a trailer is to haul a boat. In such applications, the trailer often is partially submerged in water when loading and unloading the boat. Use in or near water militates against the use of electrically actuated systems. Even without the presence of water, electrically operated systems require a connection to an electric power source (usually that of the towing vehicle) and present complications and reliability concerns. Hand-pumped hydraulic or hand-cranked mechanical systems avoid these shortcomings, but require the use of at least one of the operator&#39;s hands, which leaves only one (if any) hand free to manipulate the hitch or perform other operations. Moreover, the level of the lift and trailer tongue is usually low enough to the ground to make hand operation awkward and possibly unsafe.  
         [0008]     A need exists, therefore, for a lift mechanism or apparatus for a wheeled trailer that has simple, reliable construction and that is safe, easy, and convenient to use.  
       SUMMARY OF THE INVENTION  
       [0009]     It is a general object of the present invention to provide an improved lift for a wheeled trailer to be towed behind a vehicle. This and other objects of the invention are attained by providing an hydraulically extensible frame that is coupled to the hitch portion of the trailer by a pivoting mount. The pivoting mount permits the frame to pivot between a generally vertical operative position and a generally horizontal stowed position. A foot member is secured to an end of the frame opposite the pivoting mount. The foot member engages the ground. An actuator is carried by the frame in a location adapted to be engaged by a foot of a human user when the frame is in the operative position. The actuator selectively extends the frame to raise the hitch portion in response to actuation by the foot of the user.  
         [0010]     According to the preferred embodiment of the present invention, the frame further comprises a bottle jack having a cylinder and a rod, the rod being selectively extensible from an end of the cylinder responsive to actuation from the actuator.  
         [0011]     According to the preferred embodiment of the present invention, a tubular member carried concentrically and in sliding relation about the cylinder of the bottle jack, the tubular member being secured to and movable with the rod.  
         [0012]     According to the preferred embodiment of the present invention, the actuator further includes a biasing member to maintain the actuator in an operative position.  
         [0013]     According to the preferred embodiment of the present invention, the actuator comprises an actuator hydraulic cylinder in fluid communication with the hydraulic cylinder, the actuator cylinder including an actuator rod.  
         [0014]     According to the preferred embodiment of the present invention, a foot pedal is operatively coupled to the actuator rod, the foot pedal being biased in an upward position by the biasing member.  
         [0015]     According to the preferred embodiment of the present invention, the wheeled trailer is adapted to carry a boat.  
         [0016]     Other objects, features, and advantages of the present invention will become apparent with reference to the drawings and detailed description, which follows.  
     
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       [0017]      FIG. 1  is an elevation view of a wheeled trailer including the lifting apparatus according to the present invention.  
         [0018]      FIG. 2  is an enlarged elevation view of the lifting apparatus of  FIG. 1  in a deployed or near-vertical position.  
         [0019]      FIG. 3  is an elevation view of the lifting apparatus of  FIGS. 1 and 2  pivoted into a stowed or near-horizontal position.  
         [0020]      FIGS. 4 and 5  are an enlarged elevation view, partially in section, of the lifting apparatus of  FIGS. 1, 2 , and  3 .  
         [0021]      FIG. 6  is an enlarged, fragmentary view, partially in section, of the attachment or mounting of a portion of lifting apparatus according to the present invention to a portion of the trailer.  
     
    
     DETAILED DESCRIPTION  
       [0022]     Referring now to the Figures and particularly to  FIG. 1 , the numeral  1  designates a wheeled trailer of the type with which the present invention is employed. The present invention is particularly adapted to those wheeled trailers that are adapted to haul or carry boats  3 , such as that illustrated in  FIG. 1 , because of the relatively great loaded weight of such trailers and the frequency with which they are coupled and uncoupled from a towing vehicle. As can be seen, trailer  1  has a hitch  5  at a forward portion thereof, which is secured to a tongue portion  7  of trailer  1 . Typically, hitch  5  is a socket member that registers with a corresponding hitch ball (not shown) on a towing vehicle (also not shown).  
         [0023]     A lifting mechanism or apparatus (“lift”)  11  according to the present invention is secured to a tongue portion  7  of trailer proximal to or near hitch  5 . As shown in  FIG. 1 , lift  11  serves as a third wheel or support to maintain trailer  1  in a generally level orientation when trailer  1  is not coupled to a towing vehicle. A lift  11  according to the present invention finds particular utility in those trailers  1  adapted to carry or haul boats because such trailers often are extremely heavy and incapable of being manipulated solely by a user, without the assistance of a mechanical advantage.  
         [0024]      FIGS. 2 and 3  are enlarged elevation views of the lift  11  according to the present invention illustrating the lift in a deployed or near-vertical position ( FIG. 2 ) and a stowed or near-horizontal position ( FIG. 3 ). Lift  11  generally comprises a hydraulically extensible frame  13  that is coupled to a generally horizontally extending portion of trailer tongue  7  by a pivoting mount or bracket  15 . At its lower end, frame  13  terminates in a foot member, which is preferably a wheel but may be another type of support. Additionally, frame  13  (and lift  11 ) is provided with an actuator  19  in the form of a foot pedal. Foot pedal  19  is arranged to be no higher than a selected height h of about 18-24 inches so that it is adapted to be engaged and operated by a foot of a human user.  
         [0025]      FIGS. 4 and 5  are enlarged elevation views, partially in section, of lift  11  according to the present invention.  FIG. 4  depicts lift  11  in a retracted or fully compressed stated while  FIG. 5  depicts lift  11  in an extended state in which tongue  7  of trailer  1  is being (or has been) raised by lift  11 . The hydraulically extensible frame ( 13  in  FIG. 2 ) of lift  11  comprises a conventional bottle jack, which has an hydraulic cylinder  21  and a rod  23  extending or protruding a selected and variable distance from cylinder  21 . According to the preferred embodiment of the present invention, the bottle jack is commercially available, such as the AC-Delco® Hydraulic Bottle Jack, Model 34112.  
         [0026]     Rod  23  terminates at its end in a cylindrical member  25 , which preferably is a steel cylinder welded to the end of rod  23 . Rod  23  preferably has a threaded exterior and its protrusion from cylinder  21  is adjustable by rotating rod  23  relative to cylinder  21 . This provides an adjustment of the overall height of frame  13  to accommodate towing vehicles with differing bumper (and hitch) heights. A conventional bolt  27  extends through cylindrical member  25  to couple a tubular frame member  29  to rod  23 . Rod  23  is the portion of the bottle jack that extends upwardly from cylinder  21  responsive to hydraulic actuation of the bottle jack. Tubular frame member  29  thus moves up and down with rod  23  relative to cylinder  21 . Tubular frame member  29  is dimensioned to slide concentrically over and cover cylinder  21 . In the fully compressed position depicted in  FIG. 4 , cylinder  21  of the bottle jack is almost completely covered by frame member  29 .  
         [0027]     Foot pedal or actuator  19  is coupled to an actuator cylinder  31  and actuator rod  33 . Actuator rod and cylinder  31 ,  33  are part of the bottle jack and operate to exert pressure on the hydraulic fluid in cylinder  21  of the bottle jack, thereby extending rod  23  from cylinder  21  and raising or extending the frame of lift  11 , in turn raising tongue  7  of trailer  1 . As noted previously, actuator pedal  19  is designed, intended, and adapted to be operated by the foot of a human user. Accordingly, it is preferably no higher than a height h of about 18 inches from the ground when lift  11  is in the deployed position. Height h should not exceed 24 inches if an average human operator is to use lift  11  without risking the loss of balance.  
         [0028]     In addition to being positioned to be engaged by a foot, foot pedal or actuator  19  is biased into an upward position by a compression coil spring or biasing member  41 . Spring  41  maintains pedal  19  in the upward position at all times (except when pedal  19  is depressed by an operator) and permits the operator&#39;s foot to do actuation work only on the downward stroke of pedal  1 . Spring  41  is captured between pedal  19  and base plate  47  of the bottle jack by a tube  43 . The upper extent of spring  41  is covered with a plastic or metallic bellows  45  for aesthetic and functional purposes (to improve appearance and to keep materials from being pinched or caught in spring  41 ).  
         [0029]     A stopcock  37  functions to release pressure within the bottle jack, thereby permitting rod  23  and tubular frame  29  to compress or retract relative to bottle jack cylinder  21 , in turn lowering tongue  7  of trailer  1 .  
         [0030]      FIG. 6  is an elevation view, partially in section, of pivoting mount  15 , taken along the section line  6 - 6  of  FIG. 5 . Mount  15  comprises a pair of parallel, spaced-apart plates  51  that are secured to either side of the box-girder of trailer tongue  7  by four bolts  53 , two of which are shown in  FIG. 6 . A bracket  55  is mounted for rotation on one of plates  51  by a pivot or axle  57 . Bracket  55  is, in turn, welded to tubular frame member  29 .  
         [0031]     A U-shaped, spring-loaded handle  59  is secured to bracket  55 . One end  59 A of handle  59  extends through an aperture in bracket  55  and into an aperture in plate  51 , thereby securing bracket  55  and tubular frame member  29  of lift  11  against rotation relative to trailer tongue  7 . By pulling outward (to the right in  FIG. 6 ) on handle  59 , end  59 A is disengaged from the aperture in plate  51 , freeing bracket  55 , frame  29  and lift  11  to pivot between the stowed and deployed positions illustrated in  FIGS. 2 and 3 .  
         [0032]      FIG. 6  also illustrates a fixed height adjustment provided for lift  11  by holes or apertures  29 A formed in the wall of tubular frame member  29 . By removing bolt  27 , moving frame member  29  relative to cylindrical member ( 25  in  FIGS. 4 and 5 ) into alignment with one of the other apertures  29 A, and re-inserting bolt  27 , the overall height of lift  11  can be adjusted in a fixed fashion, without regard to the level of extension of rod ( 23  in  FIGS. 4 and 5 ) relative to cylinder ( 21  in  FIGS. 4 and 5 ) or tubular member  29 .  
         [0033]     In operation, lift  11  is coupled to tongue  7  of trailer near hitch  5  as shown in  FIGS. 1 and 6 . Frame  13  of lift  11  is pivoted to the deployed or near-vertical position as shown in  FIG. 2 . Lift then is capable of supporting the forward or front end of trailer  1 , even under load. To couple hitch to a towing vehicle, foot pedal  19  is actuated by an operator&#39;s foot, extending rod  23  from cylinder  21  and extending tubular frame  29  relative to foot member  17 , thereby raising tongue  7  relative to the ground. Tongue  7  and hitch  5  may then be aligned, with the assistance of wheeled foot member  17 , over the hitch ball. Stopcock  37  is then released to permit rod  23  to retract into cylinder  21  and frame member  29  to retract relative to foot member  17 . Tongue  7  and hitch  5  then are lowered into engagement with the hitch ball. The process is essentially reversed to disengage or uncouple trailer  1  from the towing vehicle. Additionally, by manipulating handle  59  of mount  15 , lift  11  may be pivoted between stowed and deployed positions to facilitate towing trailer  1  over uneven terrain.  
         [0034]     The lift according to the present invention has a number of advantages. It is hydraulic, so it is smooth in operation and avoids the potentially dangerous “kickback” and backlash sometimes encountered in purely mechanical systems. It is not electrically operated, making it safe and reliable even in marine environments. It is operated by the foot and leg muscles of the operator, which are stronger than hand and arm muscles. Further, foot operation or actuation permits the operator to keep his or her head or face away from trailer and hitch components for safety in the event of failure. The lift according to the present invention is simple in construction and operation, making manufacturing, repair, and replacement inexpensive.  
         [0035]     The invention has been described with reference to a preferred embodiment thereof. It is thus not limited, but is susceptible to variation and modification without departing from the scope of the invention.