Pneumatic lift for single axle trailer

A trailer assembly comprising:

• an axle having fittings for receiving bearings and wheels for rolling movement over the ground;
• a chassis disposed on the axle, the chassis including a tongue for attachment to a tow truck for transporting the trailer assembly;
• a strut pivotally secured to the tongue having a length sufficient to permit an end portion of the strut to engage the ground as the tongue is lifted for attachment to the tow truck;
• and
• a cylinder assembly having a housing for receiving compressed air and a piston movable along the axis of the cylinder in response to pressure exerted by compressed air contained in the cylinder, the housing being pivotally secured to the tongue to permit angular displacement of the cylinder with respect to the chassis, and the piston being pivotally secured to the strut to permit angular displacement of the cylinder with respect to the strut as the position is displaced within the housing.

A jack assemby for lifting the tongue of a trailer comprising, in combination:

• a frame for attachment to the tongue of the trailer;
• a strut having a first end portion pivotally secured to the frame and having a second end portion for engaging the surface upon which the trailer rests as the tongue is lifted;
• and,
• a cylinder having a chamber for receiving pressurized, compressible fluid and a piston operably disposed within the chamber for transmitting a mechanical force proportional to the pressure of the fluid contained therein, the cylinder being pivotally secured to the frame and the piston being pivotally secured to the strut whereby the cylinder and strut are displaced angularly with respect to the frame as the piston is displaced within the cylinder.

In combination:

• a single axle trailer havig a load bearing frame and a tongue for attachment to a tow truck,
• a tank of compressed air carried by the trailer;
• a ground engaging strut pivotally secured to the tongue;
• and,
• a linear actuator operable to develop a mechanical force from fluid power derived from the tank of compressed air, the linear actuator including a housing having a pressure chamber and an extensible piston disposed in the chamber, the chamber being connected in fluid communication with the tank of compressed air, the housing being pivotally secured to the tongue, and the piston being pivotally secured to the strut, whereby the linear actuator and the ground engaging strut cooperate to lift the tongue as the chamber is pressurized.

In a portable utility trailer assembly of the type including a frame supported by a single axle and having a tongue assembly including a hitch and coupling pin projecting from the frame for hookup to a tow truck, the combination with the trailer assembly of:

• a pneumatic jack assembly and a source of compressed air operably connected thereto for assisting an operator in lifting the tongue to engage a hitch receptacle on the tow truck, the jack assembly including a ground engaging strut pivotally secured to the tongue, a pneumatic power transducer having a pressure chamber connected to receive compressed air from the compressed air source and an actuating arm operably coupled to the pressure chamber for transmitting a mechanical force in response to power derived from the compressed air in the pressure chamber, the power transducer being pivotally secured to the tongue and the actuating arm being pivotally secured to the strut to permit rotational movement of the power transducer and tongue relative to each other and relative to the strut as the tongue is lifted by the force exerted by the power transducer through the actuating arm;
• a spring having an end portion secured to the tongue and an opposite end portion secured to the strut, the spring being stretched by the movement of the tongue relative to the strut when the actuating arm is extended, the stretched spring applying a recoiling force to retract the strut and actuating arm when the pressure chamber is de-energized;
• and,
• a latch having a first end portion for confining the coupling pin in registration with the hitch and coupling member and having a second end portion for engaging the strut, the latch being pivotally secured to the tongue and rotatable to a first position to permit access to the coupling pin when the strut and actuating arm are extended, and being rotatable to a second position wherein the coupling pin is confined by the first end portion and the second end portion is confined by the strut when the strut and actuating arm are fully retracted.

A jack assembly for lifting the tongue of a trailer comprising, in combination:

• a frame for attachment to the tongue of the trailer;
• a strut having a first end portion pivotally secured to the frame and having a second end portion for engaging the surface upon which the trailer rests as the tongue is lifted;
• a cylinder having a chamber for receiving pressurized fluid and a piston operably disposed within the chamber for transmitting a mechanical force proportional to the pressure of the fluid contained therein, the cylinder being pivotally secured to the frame and the piston being pivotally secured to the strut whereby the cylinder and strut are displaced angularly with respect to the frame as the piston is displaced within the cylinder;
• a spring having a first end portion secured to the frame and having a second end portion secured to the strut for retracting the strut and piston when the cylinder is de-energized;
• and,
• wherein the trailer tongue includes a hitch for engagement with the coupling receiver of a tow truck and a coupling pin is provided for insertion into the hitch and coupling receiver, the jack assembly further including a latch pivotally secured to the frame, the latch having a first end portion for confining the coupling pin and a second end portion for engaging the strut, the latch being rotatable to a first position to permit access to the hitch when the piston and strut are extended, and the latch being rotatable to a second position wherein the first end portion of the latch is disposed over the hitch to confine the coupling pin as it is disposed within the hitch and coupling receiver and the second end portion of the latch is engaged by the strut when the piston and strut are fully retracted.