Morris took the rod weeder one step further.
http://pami.ca/pdfs/reports_research_updates/(10h) Rod Weeders/687.PDF
We tested their "Dead Rod" on their chisel plow, and it worked actually quite well. It mounted on 2 shanks, and a few mounted on 3 shanks. The brackets were designed, so when installed properly, there was some overlap of the rods.
If you remember the Seed Rite Rod Weeder grain drills, they were experimenting with a hydraulic driven rod, like on the 7000 rod weeder, but on an air seeder and on an air drill. It worked well also in the air seeder with wide shovels, but had some problems on the air drill in harder direct seeding. On both the air drill and the air seeder it ran ahead of the packers, and it had a tendency to stand the root balls of the previous crop back upright and then the packers press them back into the ground resulting in more standing stubble. The pictures on the PAMI report are actually from the air seeder tests. It did leave a nice smooth field.
There were others in the rod business and those chisel plow add on kits were popular already back in the 60s from Deere and others. I have two of those, think they were called the 1000, were on chisel plows I bought from my uncle, one on a 30ft 250F and a 16 ft 600 with the pig tail shanks. Were ground driven off the tires by a small tire that was spring loaded against the other.
Trouble with those shank mounted rods, is they are no good if you have large rocks as the individual shanks can't travel back far enough to clear the obstruction without bending the rod. And on the Deere shanks with spring trip version, you had to remove the springs on the shank that the drive boot was mounted on, so now you had three solid shanks as well.
There was literally dozens of short line outfits selling the add on rod kits, some live, some dead and a few hydraulic from the 50s thru 80s. Deere had one available for the 1610 chisel plow even. A lot of guys were even just dragging 1 1/4 polish rods on chains behind their cultivators as well, was several ideas all told. I have Deere catalogs from the 1930s that have rod weeders in them, it is definitely old tech that has been around for a long time. Morris was always knows for being the rod weeder king, but he didn't invent it, but he did massively improve it.
As for the demise of the Seedrites, Morris had worked with an air tank fed version, but as was an issue with the box drills, in hard unworked ground there wasn't enough weight to get the hoes in the ground, even with the rod pinned up. That coupled with transport issues did them in. I actually spoke with Morris' R&D dept years back about those machines and if any prototypes still existed, but they were cut up for scrap soon after the entire Seedrite concept was abandoned and they moved onto other technologies.
Remembered I had these pics on my computer from a previous thread a while back, figured might be some who have never seen one of those Seedrite drills. This is one 18 ft of two that were pulled together.