The Talking Machine Forum — For All Antique Phonographs & Recordings

US Patent number 2,047,160

I first discovered this patent when restoring the first 10-50 that came into my collection in 1991. At that time, before the Internet, this required a trip to the USPTO in Crystal City, VA. After a day of searching the dark corridors of the Patent Office I discovered this. The title was not a particularly good clue in the search but narrowing it down by the Assignee and approximate date helped. In the stacks of paper on the shelves I found the Offices’ copy, quickly paid the duplication fee and hurried home to work on my machine.

The Internet and Google Patent search has certainly opened the world to patent searches to everyone. No trip to Crystal City, VA is needed any more!

The exact replica 10-50 changer parts which we are about to introduce are a partial result of this patent. The drawings are highly detailed and are likely the engineering drawings produced by Victor. Like most or all patent drawings they are designed to illustrate the patentable feature and contain no dimensions. Comparison with existing parts to figure out dimensions was not much help likely because of changes during duplication or printing. Still, the drawings provided some valuable clues which lead to ultimate success in producing the replacement parts.

Note the filing dates and the granted dates. The grant date was well after the 10-50 was obsolete.

Note also the inclusion of the dual tonearm in Sheet 9, as used on the 8-60 and 9-40. It was apparently planned since the bedplate casting, as pointed out by forum member Carsten Fisher, has a place for the rotary Victrola/Electrola change valve. It ultimately was not implemented in the 10-50. There is some discussion of this deletion in the Victor meeting notes at the Hagley museum.

I’m so glad this document survives!

Mark

Lots of detail in there. Thanks for sharing!

Mark (or Carston) -

Can you please show us, preferably by marking up the patent drawing(s), where the bedplate has the spot for the Electrola valve?

Thanks.

Here is some photo evidence of where Victor was going with the dual pickup idea. The height of the short cast iron throat in the 10-50 plumbing exactly matches the height of the 8-60/9-40 Victrola/Electrola changeover valve so it seems likely that it was intended to be an either/or option. The shape and bolt pattern on the underside of the main changer plate matches the valve although the position of the two ball bearing detents do not. It looks like a work in progress. I need to give credit to Carsten for first noticing this feature. Every first style changer main plate casting incorporates this.

Mark

Ok that’s super cool and amazing. Good ole Carsten!

I’m thinking I might want to soup up my 10-50 by adding a valve, then electronics. I already have a spare dual tonearm u-tube. How hard do you think it would be to adapt the valve?

PeterF wrote: Mon Nov 14, 2022 3:35 pm Ok that’s super cool and amazing. Good ole Carsten!

I’m thinking I might want to soup up my 10-50 by adding a valve, then electronics. I already have a spare dual tonearm u-tube. How hard do you think it would be to adapt the valve?

I suspect that adding the valve would require additional hardware to be made to allow it to function properly as the top of the casting does not have the pivot point for the inside of the valve and there is nowhere for the felt gasket to sit. My guess is that they would have cut a simple plate the thickness of the raised portion of the straight cast piece and embedded all the needed detents and pivots into there.
It seems the decision not to include the valve was made quite late in the development of the machine so I think that it would probably fit in the cabinet. Of coarse the cabinet doesn't seem to have any hole drilled for the valve gearing and lever so maybe they made this decision before finishing the cabinet.
Here is a meeting minute dated march 9 1927

Bronson,

Thanks for your comments and for posting the Victor meeting notes.

Regarding the cabinet, I believe that accommodation was made for the secondary shaft that would have controlled the rotary Electrola/Victrol or “radio valve” as the notes call it. Notice the half-round groove in the wooden block that supports the changer chassis. The groove aligns vertically with the record-size change shaft and the position matches photos of a dual pickup 10-50 type machine. The dual machine has two handles side by side on the front panel.

Notice the alternate link-type 10/12” record size change mechanism that Bronson and I developed. It Is simple, provides positive action with less gear backlash (play), is less expensive to produce than one containing the four brass gears, mounts directly to the existing holes and eliminates those troublesome pot-metal problems. Also, the control handle still indicates the correct setting on the front panel escutcheon. If you need one a few extras along with some handles are available to help the hobby. It can be installed without needing to remove the changer from the cabinet.

Mark