Patent Application
20060214390
1. Field of the Invention
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.
2. Summary of the Prior Art
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.”
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.
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.
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'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.
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.
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.
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.
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.
According to the preferred embodiment of the present invention, the actuator further includes a biasing member to maintain the actuator in an operative position.
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.
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.
According to the preferred embodiment of the present invention, the wheeled trailer is adapted to carry a boat.
Other objects, features, and advantages of the present invention will become apparent with reference to the drawings and detailed description, which follows.
Referring now to the Figures and particularly to
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
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
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.
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'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).
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.
A U-shaped, spring-loaded handle 59 is secured to bracket 55. One end 59A 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
In operation, lift 11 is coupled to tongue 7 of trailer near hitch 5 as shown in
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.
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.
