Portable trailer stabilizers

A portable trailer stabilizer, comprising:

• a support surface engagement element configured to selectively engage a support surface;
• a trailer engagement element configured to selectively engage a forward end portion of a trailer;
• a hydraulic cylinder operative to extend the trailer engagement element relative to the support surface engagement element;
• a hydraulic accumulator operatively coupled to supply pressurized hydraulic fluid to the hydraulic cylinder, the hydraulic accumulator forming an on-board, self-contained energy source;
• an isolation valve fluidically interposing the hydraulic cylinder and the hydraulic accumulator in a closed hydraulic system;
• a fifth wheel plate configured to selectively couple with a fifth wheel of a tractor capable of towing the portable trailer stabilizer;
• a valve operator mechanism configured to (i) open the isolation valve when the fifth wheel plate is coupled to the fifth wheel of the tractor, and (ii) shut the isolation valve when the fifth wheel plate is uncoupled from the fifth wheel of the tractor;
• and
• a frame that carries the support surface engagement element, the trailer engagement element, the hydraulic cylinder, the hydraulic accumulator, the isolation valve, the fifth wheel plate, and the valve operator mechanism.

A portable trailer stabilizer, comprising:

• a ground pad configured to selectively engage a support surface;
• a trailer engagement element movable relative to the ground pad, the trailer engagement element configured to selectively engage a forward end portion of a trailer;
• a structural element supporting the trailer engagement element above the surface engagement element;
• a closed hydraulic system containing a hydraulic fluid, the closed hydraulic system comprising
• a hydraulic cylinder operatively connecting the structural element and the trailer engagement element, the hydraulic cylinder configured to extend the trailer engagement element relative to the support surface engagement element,
• a hydraulic accumulator operatively coupled to the hydraulic cylinder, and
• an isolation valve fluidically interposing the hydraulic cylinder and the hydraulic accumulator;
• a positioning element engagement element configured to selectively couple with a trailer stabilizer positioning element of a tractor;
• a valve operator mechanism configured to (i) open the isolation valve when the positioning element engagement element is coupled to the trailer stabilizer positioning element of the tractor, and (ii) shut the isolation valve when the positioning element engagement element is uncoupled from the trailer stabilizer positioning element of the tractor;
• and,
• a frame that carries the ground pad, the trailer engagement element, the structural element, the closed hydraulic system, the positioning element engagement element, and the valve operator mechanism.