Does anyone know what year the first horizontal "key slot" and the use of the key first appeared in the sides of MCB coupler shanks?

Also, what was the use for this first key and slot?

The reason I ask is because I see some real old MCB couplers with MCB really old coupler contours that have key slots in the sides of their shanks.

Is it possible that they key slot in the early MCB coupler shank had some other earlier use that preceded the USRA cast steel draft yoke (that used the same key slot and key)?


read this exerpt from a 1905 Railway Age;
http://books.google.com/books?id=_X9NAA ... ey&f=false

The first use may have been for the continuous drawbar such as the "Improved American Draft and Buffing Apparatus" shown in figures 1940 and 1941 of the 1895 Car Builders Dictionary. In this design a pair of steel rods, on either side of the couplers, connected the coupler shanks beneath the wooden car. The flattened rod ends slipped over the ends of the key that extended through the hole in the coupler shank.

Mike Manson

NWPRRHS

Mike Excellent, you found the evidence. That was probably the first use of the key.

So now I need to answer the question about the location of the key (did it move around or is it in the same location) when the key was used in conjunction with the two large perpendicular rivets that attach the yoke to the butt top and bottom.

I found the answer on fig. 2088 just a few pages below your fig. 1940 find. Fig 2088, the Buckeye "little Giant' coupler, this shows the key slot going through the first rivet hole and the back wall of the key slot lining up with the same back wall of the front rivet hole, that is the exact same location as used on every 3' gauge shank, and older small standard gauge shanks, that has the key slot in it, some were cast without them.
Also see 2011a, 2150 2152, 2140 2141, they all have the key slot in the same location as the contemporary shanks today (except for the super-strength shanks that were redesigned for unit trains and other failure prone installations that have had to be strengthened).

The key slot goes through the rivet hole (in the figures), so the keys back then could have had a locating hole, or slot cutout of them, allowing them to be secured to the shank by driving in the first rivet, (that would have gone through the key). So the rivets and the keys were a system that were used together, the key and the rivets hold each other together. Thats brilliant and its still the same today!

Mystery solved.

The key slot, on the typical shank used on light equipment is still in the same location as it was back in 1895. The key slot was there originally to attach the CC-draw gear to the key itself on the sides of the shank (ref; 1905 MB convention notes from Railway Age).

Fig. 1939 shows the "tail bolted" version of the CC draw gear (that Jason M. mentioned) and a version of the "rod holding box" is shown there also.

So just about everthing to do with the shanks is still the same as it was in 1895. Thats what I needed to know. The key slot is still in that same 1895 location today on the small to medium sized AAR shanks.

That MCB group back then, they were thinkers and they planned way ahead!

Thanks

Loco112

Continuous drawbars can be seen on the C&TS on the 04000 series work cars. One broke when they were initially moving equipment with the recent purchase of the states in 1970.

Robby Peartree