Great minds, and all that…
I suspect the end loops were there so people wouldn’t poke their hands on the hook’s pointy ends while picking up or replacing the earpiece.
There would be a lot of alternatives to casting those loops. That piece would be fairly expensive to make, maybe requiring shaping of the final piece, and then smoothing the piece so it wasn’t cutting fingers.
The OP has brought up an interesting question since there’s no apparent functional reason for the loops. Ornate castings were common in that time period, and those phones were high tech for the time, but the rest of the device is mainly utilitarian in design.
My guess:
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Obviously you want some kind of protrusion or upward bend at the end of the hook, to prevent the earpiece from falling off the hook.
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This part can come in contact with the user’s hand, so you don’t want a pointy end or sharp edges.
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The hook itself should be lightweight, because the weight of the earpiece activates a switch.
A circular hoop satisfies all these requirements.
That’s a very reasonable analysis, but the loop ends aren’t the only way to do the same thing, and they would be one of the more expensive approaches. Some phones had similar hook switches that were made of sheet metal, probably stamped, and much less expensive. The cast loop switches (actually actuator arms for the hook switch) evolved over time, the originals probably did jab a few people with pointy their pointy ends. By the time they arrived esthetics would be more of a consideration, and I imagine the phone manufactures were making money hand over fist, trying to keep up with demand, and may have just stuck to the design used in a phone that sold well.
This is something only going back a century, I’ll bet someone out there knows the detailed history of these phones and that hook design.
Isn’t it possible to make this whole shape by stamping sheet metal? Here’s a photo of a hook by itself, though it’s a reproduction. It looks like it could be made from two pieces of stamped sheet metal that are fastened together (riveted?).
Certainly. But I’ve seen the pieces that were obviously cast, or at least required a good bit of finishing work to give them rounded edges all over so they didn’t look like stamped pieces. It would be interested to find out which loop shaped pieces came first, cast or stamped.
I see what you guys are talking about. My guess is that as these would have originally been hand made, or had a lot of human labor involved. So, when you take a flat piece of metal and want to expand it you drive a chisel or wedge into it while hot. The metal will expand around and become larger. The only other option would be to create two discs and weld them onto the metal, which adds to the effort and you have a point of failure.
So, my guess is that the hook was a flat strip, they then hammered in the chisel to expand the metal, did some additional work to make it nice and round, and then the final shape.
Later on, when the process would have been finalized, and they needed more of them. Using automation would help. So, they probably used a stamping process to create the hook. They also probably used a piece of metal that was larger than the diameter of the loops so they’d be “cutting out” the shape of a flat strip of metal. This is actually easier and more reliable and the scrap would then be recycled. This would also lead to the possibility of having them solid, or, in some cases when I look online, I see some purposeful cutouts.
Like this:
This is theearliest patentI could find with that shape of hook. It describes the lever as having a "bell crank " shape.
An actual bell crank, like this, would have ropes or cables attached to the loops. Maybe this was a way to reuse parts and caught on or this particular design was just copied. I couldn’t find much more information on it.
I’ll add a wag;
The hook has no preferred orientation in the final assembly so make it symmetrical.
Both loops and discs work for that.
CMC fnord!
Is it possibly a styling element of the era? Kinda like how everything from the 1980’s had to have neon colors or computer fonts.
Solid parts were more difficult to cast than open parts. The edge cools down first, fixing the radius at the “hot” dimension, then the centre cools down under tension, and cracks or, more likely, warps the shape. It’s also a waste of material, and makes the part heavier. It’s more of a problem with bigger objects, but I would imagine that both designers and end-users were more acustomed to seeing open-loop designs for metalwork. (Open loop designs also mimick wrought metal work)
My thought was to reduce the mass of the hook so that a weaker return spring could be used.
Pencil holder?
–Wow! I’d be hard pressed to believe that was the intent of the design, but I’m willing to bet that it was the ad hoc usage by thousands of phone owners.
Looking at Folly’s patent link, apparently there were multiple non-trivial issues with hook usage by everyday folk. The springs, switches, etc. seemed to fail quite easily.
One common use of the hook in the old days, besides holding the ear piece when not in use, was to repeatedly click it to get the operators attention. Having a nice “nub” that the user can flick up and down helps. And reducing weight, increasing longevity must have all played a role.
Given the base and stand aren’t perforated with a bunch of holes to prevent cracking or anything indicates that they could have easily have made the nubs solid if they wanted to.
[Bart Simpson]
Me-tal
[/Bart Simpson]
Maybe Mr. Engstrom was the first one with a design that looked like that. He seemed to get some recognition for that patent.