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Trailer snaking accident

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3 hours ago, htb said:

I think the towing pintle  needs to be locked for road use when used with a trailer with a rotating hitch in case the hitch rotated to face down loading the catch, hope this makes sense. If the trailer has a non roating hitch then the nato should be unlocked

I believe that to be the reason too.

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The DB NATO pintle is now type approved.

 

When towing any type of trailer using a NATO pintle and lunette, whjether on or off the road, either the lunette or the pintle but not both must be able to rotate. Early trailers had rotateing lunettes and requred a locked pintle, more recent (widetrack) trailers have a fixed lunette and require a rotating pintle.

 

The basic reason why one must rotate is to allow articulation between the trailer and the towing vehicle. The reason however why trailers now have fixed (non-rotating) lunettes is a little more complex to understand (and very difficult to explain in words without pictures) but is as follows.

 

If a trailer with a rotating lunette is at a sharp angle to the towing vehicle, ie jacknifed or approaching jacknifed, the lunette will drop down the pintle so that instead of the lunette being horizontal, it is vertical. The noseweight of the trailer makes this inevitable. AS the towing vehicle then pulls forward, the lunette will not revert back to the horizontal since there is nothing to lift the dropped side of the ring back up. The result is that either the shaft of the lunette will bend, or the rear cross-member of the towing vehicle will bend, or the pintle willbe ripped clean off the towing vehicle. This is the reason that many early Sankey trailers were cast with severly bent lunette shafts.

 

The later trailes have fixed, non-rotating lunettes, so that if turned thrugh the same (jacknife) angle the lunette remains horizontal. As a result, when the towing vehicle pulls forward, there is absolutely no problem and nothing gets bent. 

 

Whenever a NATO pintle is used it is essential that a locking pin is used to keep the pintle jaw locked shut, the hitch is insecure without one. With a locking pin, the jaw will tow completely safelt upside-down, although this is clearly not the correct way to use it.

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3 hours ago, Treewolf said:

The DB NATO pintle is now type approved.

 

When towing any type of trailer using a NATO pintle and lunette, whjether on or off the road, either the lunette or the pintle but not both must be able to rotate. Early trailers had rotateing lunettes and requred a locked pintle, more recent (widetrack) trailers have a fixed lunette and require a rotating pintle.

 

The basic reason why one must rotate is to allow articulation between the trailer and the towing vehicle. The reason however why trailers now have fixed (non-rotating) lunettes is a little more complex to understand (and very difficult to explain in words without pictures) but is as follows.

 

If a trailer with a rotating lunette is at a sharp angle to the towing vehicle, ie jacknifed or approaching jacknifed, the lunette will drop down the pintle so that instead of the lunette being horizontal, it is vertical. The noseweight of the trailer makes this inevitable. AS the towing vehicle then pulls forward, the lunette will not revert back to the horizontal since there is nothing to lift the dropped side of the ring back up. The result is that either the shaft of the lunette will bend, or the rear cross-member of the towing vehicle will bend, or the pintle willbe ripped clean off the towing vehicle. This is the reason that many early Sankey trailers were cast with severly bent lunette shafts.

 

The later trailes have fixed, non-rotating lunettes, so that if turned thrugh the same (jacknife) angle the lunette remains horizontal. As a result, when the towing vehicle pulls forward, there is absolutely no problem and nothing gets bent. 

 

Whenever a NATO pintle is used it is essential that a locking pin is used to keep the pintle jaw locked shut, the hitch is insecure without one. With a locking pin, the jaw will tow completely safelt upside-down, although this is clearly not the correct way to use it.

Understood perfectly ans eloquently put .

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