After spending awhile pondering an easy and safe way for a car or truck to push a trailer in reverse, I tested one method with a model made from Knex the construction toy and drew a schematic of the results. Instead of unstably pushing a trailer via its tongue, the tow vehicle pulls the trailer from its rear.

This is done by using a bar that becomes an extension of the car’s centerline. The bar is a part of the trailer’s understructure, connected to its back end with a flexible joint, but is held solidly by the hitch so it is always parallel to the tow vehicle’s direction when in reverse. This has the same positive effect as if an imaginary car facing the other way were behind the trailer, towing it.

While traveling forward, the usual hitch-trailer tongue would be used, but as soon as one starts backing up (noted in the electrical harness), the tongue coupler is released while the bar end is held fast by the modified hitch. When moving forward again, the bar is released after the tongue is again coupled.

Some difficulty arises upon change of direction when the two vehicles are at an angle to each other. This means that the trailer tongue must be pulled to the hitch, or the bar pulled into alignment with the car, hydraulically during the initial movement in the new direction forward or reverse, respectively. The forces needed seemed minor.
-- FarmerJohn, Jan 09 2005

schematic http://www.geocitie...railerbacking.html?
[FarmerJohn, Jan 09 2005]

(??) Steerable Tow Hitch Steerable_20Tow_20Hitch
A better idea (in my opinion). [BJS, Feb 10 2006]

...picturing the entire bar cheering on some poor devil attempting to back.....
-- normzone, Jan 09 2005


Cool idea. I'm just afraid that long bar, with all that leverage, will bend.
-- robinism, Jan 09 2005


Obviously, the bar and hitch would be built to withstand the horizontal loads which didn't appear to be great as the trailer obligingly turns and follows the bar end.
-- FarmerJohn, Jan 09 2005


Pubs and bars help drunk truckers get back on the road via remote video cameras in their tiny parking lots.
-- mensmaximus, Jan 09 2005


It really isn't that difficult to back-up with a trailer. Millions of people do it every day, often several times.
-- ato_de, Jan 09 2005


So a whole bunch of drivers will get used to this system and then be hampered when they have to back up their trailer in all the places that don't have your system?

I think hiring drivers that move their trailers forard and reverse would be far cheaper then putting in a system for people incpable of competently driving something with as much potential for damage as a semi?

Or how about using MLS ("The Ball") like jet pilots use to land on an aircraft carrier? Curb feelers?

Or Drivers that can drive.
-- Giblet, Jan 09 2005


I too could back up with a trailer after some practice, but I know several who find it very difficult. Many people in this country rent a cargo or camping trailer for several days and might find this as beneficial as automatic transmission or cruise control.

Has this skill been added to Driver's Education? And [Giblet] that ain't no semi in the picture.
-- FarmerJohn, Jan 09 2005


I like the idea, but one problem I thought of is: single axle trailers need to be loaded so that the tongue end is a little heavier, so the trailer doesn't lift the tow vehicle. Upon switching the end of the trailer that is connected to the tow vehicle, the weight distribution will effectively be reversed.
-- swamilad, Jan 09 2005


I had imagined the front of the trailer resting on the bar nearest the car via a curved, lubricated surface.
-- FarmerJohn, Jan 09 2005


Using a butter knife and two napkins, I demonstrated your idea to my family at dinner. (they all pull trailers.) They thought it was workable, but one thought that the attachment point to the trailer should be even with the wheels.
-- robinism, Jan 10 2005


FarmerJohn, That would probably do it.

robinism, if it was even with the wheels, there would be no way to steer it, right?
-- swamilad, Jan 10 2005


[swamiland], let me get my napkins and butter knife and get back to you on that.
-- robinism, Jan 10 2005



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