Reichert 410 "Microstar IV" coarse/fine focus mechanism diagrams

[hans]

While looking for patents related to the optics I came across US 4,660,942 covering the focus mechanism. Not particularly interesting except it has more detailed drawings than the manuals I have seen. They are very close to what I remember from disassembling mine but some mundane parts (spacers/standoffs in the gear box, for example) have been omitted from the isometric view.

focus-isometric.png (135.05 KiB) Viewed 3656 times

focus-section.png (115.22 KiB) Viewed 3656 times

[Zuul]

That doesn’t exactly match either of my 410’s. I don’t know if there was much generational variation. The friction element under the left course focus is obviously different among other small differences.

One of my patents is for a specialized gear train, and the illustrations don’t match the final implementation either. The submission proceeds production by such a long period that even if you submit the design exactly (which is rare for a number of reasons) things inevitable evolve.

[hans]

That doesn’t exactly match either of my 410’s. I don’t know if there was much generational variation.

It seems like there were quite a few changes. I have one with black top and locking level for an adjustable focus stop on the left. The others have blue top and no adjustable focus stop. I also noticed in the photos you and Brian posted of your LED retrofits, both originally had circular lamp holders, while all mine are a different rectangular design with a little door that swings out for lamp replacement.

My black-top one has the second spring-loaded fine focus gear train in parallel as shown to take up backlash but my blue-top one does not and there is no sign the gears were ever installed. (The plates show obvious circular wear marks around the holes where gears were installed.) With everything cleaned and lubricated I don't notice any difference in feel and there is no backlash in either so I wonder if at some point they decided the weight of the nosepiece was sufficient and left out the parallel gear train to reduce cost?

The friction element under the left course focus is obviously different among other small differences.

Both mine have the spring washer as shown providing clamping force, but yeah, now that you mention it, looks like everything on the other side of the plate 58 near where the 74 label points was omitted from the patent drawing. On mine there is another bushing, then a plastic washer, then the gear that couples to the focus stop which is also what clamps the shaft from sliding out to the left.

[BrianBurnes]

I also noticed in the photos you and Brian posted of your LED retrofits, both originally had circular lamp holders, while all mine are a different rectangular design with a little door that swings out for lamp replacement.

I have two bodies, and there is some variation between the two. One has the circular lamp holder as you mention, and one came with the rectangular design; it's only a different plastic piece however, the hole in the metal body is still circular. More relevant, one of my bodies has an additional springloaded gear with locking mechanism attached to the focus train, the purpose of I am not sure.

[hans]

More relevant, one of my bodies has an additional springloaded gear with locking mechanism attached to the focus train, the purpose of I am not sure.

Sounds like the thing I was calling "adjustable focus stop" on the black-top stand. Have you cleaned/greased that part? Mine behaved strangely at first due to stiff grease but now behaves like a lock in one direction so you can focus above, but not below, the point you lock it. I'm not really sure of the intended use either.

[Zuul]

You are supposed to set the fine focus to the middle of the range (5 revolutions from either end iirc) and using the 10x (or 4x?) focus as well as you can with the course focus. Then you lock the course focus and, in theory, you never need to touch the course again for that session.

[hans]

You are supposed to set the fine focus to the middle of the range (5 revolutions from either end iirc) and using the 10x (or 4x?) focus as well as you can with the course focus. Then you lock the course focus and, in theory, you never need to touch the course again for that session.

Looked again at the manual I have which is newer "Leica" without the one-way lock thing and it has similar instructions except it just says to unclamp and move the whole stage up/down. It even calls that "autofocus" which I remember finding a bit strange for such an awkward procedure, but makes more sense if those used to be the instructions for the lock. Is there some common microscopy task (maybe in a clinical lab which I read somewhere was the main market for these?) where it is useful to be able to lift the objectives temporarily then bring them back down to the same position?