Trailer hitch spacer info???

[jph399]

Hey we are trying to connect our trailer to the hitch on our robot and I was hoping somone could tell me where to find the trailer hitch swivel that connects the trailer tongue to the hitch?

I dont know if we make it ourselves from electrical conduit or what.

[EricH]

Originally Posted by jph399

Hey we are trying to connect our trailer to the hitch on our robot and I was hoping somone could tell me where to find the trailer hitch swivel that connects the trailer tongue to the hitch?

I dont know if we make it ourselves from electrical conduit or what.

You have read <R18>, correct? Part C tells you that the one and only swivel point is a pin, McMaster part # 98416A009.

[Rick Wagner]

Part Number: 98416A009 $1.86 Each
Material Type
Steel

Finish
Zinc-Plated

Pin Type
Safety Pins

Safety Pin Type
Squared Retainer Snap

System of Measurement
Inch

Diameter
1/4"

Overall Length
2-13/16"

Usable Length
2-1/4"

Inside Clearance
1-5/8"

Specifications Met
Not Rated

From http://www.mcmaster.com

[jph399]

yeah I read <R18> but Im talkin about the trailer swivel in the drawing not the trailer pin.
"GE-09040" It shows a swivel that is attached to the trailer tongue and then the other end of the swivel is connected to the hitch by the pin.

Do you know where i could find this trailer swivel?

[dlavery]

Originally Posted by jph399

yeah I read <R18> but Im talkin about the trailer swivel in the drawing not the trailer pin.
"GE-09040" It shows a swivel that is attached to the trailer tongue and then the other end of the swivel is connected to the hitch by the pin.

Do you know where i could find this trailer swivel?

It is supplied during the match as part of the Trailer. The team does not supply it.

[jph399]

Originally Posted by dlavery

It is supplied during the match as part of the Trailer. The team does not supply it.

Do know of a place we can get it so that we can practice with it before we ship it?

[Vikesrock]

Originally Posted by jph399

Do know of a place we can get it so that we can practice with it before we ship it?

It is not a commercially available part, it is machined according to the drawing GE-09036 (this drawing was updated during build season, check the FIRST site for the latest version).

If you built your trailer according to the team specs the payload trailer tongue is longer than the tongue on the competition trailer to compensate for the swivel.

[jph399]

Aight thanks, appreciate it.

[writchie]

Please note that the drawing 09040 Rev A is now misleading. The changes in 9036 Rev B are not reflected.

Also note that the hitch arrangement of the team trailer as specified in the team drawings no longer has characteristics similar to the official part.

If you don't mind towing a boat trailer with a 2 /5/16 hitch with a 2 inch ball on your vehicle, then this "fine point" probably won't matter to you. If you've ever mismatched the hitch and ball sizes you'll have some idea of the effect of this change.

Make sure you load ALL of the latest drawings or you may have some surprises awaiting at competition.

[Vikesrock]

Originally Posted by writchie

Also note that the hitch arrangement of the team trailer as specified in the team drawings no longer has characteristics similar to the official part.

I don't believe I have the time or the spacial visualization skills to understand the full effects of the changes to the trailer hitch swivel.

If possible could you elaborate on the characteristics which differ from the team trailer mock-ups and suggest a way that teams could modify their team spec. trailers to behave more like the competition trailers (if this can be done)?

[writchie]

Originally Posted by Vikesrock

I don't believe I have the time or the spacial visualization skills to understand the full effects of the changes to the trailer hitch swivel.

If possible could you elaborate on the characteristics which differ from the team trailer mock-ups and suggest a way that teams could modify their team spec. trailers to behave more like the competition trailers (if this can be done)?

The change enlarged the close fit 0.26 dia hole for the hitch pin to 0.375 dia. This allows the orientation to move about plus or minus 10 degrees in pitch and roll instead of being essentially locked.

The easiest way to get close is to use the 0.625 aluminum shaft in the kit (assuming you haven't used it for other things) and bore a 0.375 hole matching 9036B. You can also round the edges of the rod. You then need to shorten the galvanized section, and drill a couple of holes vertically and horizontally to lock the aluminum pin to the tongue. This will get you close.

The aluminum is not as durable as the 1018 steel but should behave pretty much the same until you wear it out.

[MrForbes]

Thanks for bringing this to our attention. It was pretty well hidden...