iTopSpin
Current Posts => Collecting, Modding, Turning and Spin Science => Topic started by: ta0 on January 10, 2020, 01:09:45 AM
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Years ago, examining Mike Owen's collection I discovered this explosive cap top:
(http://ta0.com/museum/images/other_tops/explosive-cap-top.jpg)
This was patented in 1882 by John O. Beneke of New Orleans (US Pat. 262,354):
(https://i.ibb.co/Vx3Drh3/explosive-cap-top-USPat262354.jpg)
We didn't have caps at that time. I bought some later, but for one reason or another we didn't get to meet at his place again until last weekend.
So we could finally try it:
https://www.youtube.com/watch?v=5IZ3WuRA1Xc
Unfortunately, the caps I had stored all these years for this purpose had lost much of their power, perhaps due to humidity, and their explosion was underwhelming. We will need to try again.
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The original patent above, as well as Owen's top, has a shaft that connects the tip with the cap on the crown, transmitting the force of the ground strike.
But I found three other explosive cap peg top patents.
US Pat 282,129 By John H. Sunderman, from Quincy, Illinois, July 31, 1883:
(https://i.ibb.co/s55yrwr/image.png)
I don't think this would work well as it depends on the little inertia of the plate on the crown. So the same guy applied for another patent a few months later, US Pat 287,591:
(https://i.ibb.co/Y2PynwL/image.png)
Here he put the cap towards the bottom of the top. I think this was done to sidestep Beneke's patent (he mentioned it on the other patent, so he is aware of it), but it's more difficult to manufacture, in my opinion.
A few years later, June 12, 1894, John U. Barr from Pennsylvania got patent 521,148:
(https://i.ibb.co/hMMNNzN/image.png)
To place the cap the tip is removed. There are venting holes.
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Some one has to get this to work. They make exploding air soft bb’s.
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I am on the lookout for something like this.
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Wooo no sabía de esto estoy sorprendido ,alguna vez intenté algo pero sobre la punta ,upsss
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I love those patent drawings...
Do you have any print quality source of those or other top pattents?
I guess I should open a new thread on this... >:D >:D >:D
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I love those patent drawings...
Do you have any print quality source of those or other top pattents?
All the US patents, from the very first one, are available for download or print directly from the US Patent Office (www.uspto.gov). From 1973 onward the texts can be searched. Earlier patents are only scanned images and can only be searched by patent number, date or classification.
However, the patents are also available from Google: https://patents.google.com. It's generally easier to search and are all digitized. However, sometimes there are glitches in their database and I have to go back to the USPTO.
European patents and from several other countries are also available for download from google and directly, but unfortunately not the old ones, as far as I know.
I have printed quite a few old top patents by just browsing the corresponding classification.
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Here's an interesting, but probably dangerous idea for a pyrotechnic top.
https://patents.google.com/patent/US421424A/en?q=toy&q=top&q=spin&q=string&country=US&sort=old&page=2
(https://i.ibb.co/jM6jGsK/pyrotechnic-top.jpg)
"said top consisting of a lower section having a spindle and of an upper section having a socket for receiving a Roman candle or other piece of fire-works"
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Good find Renee! I didn't have that one in my archives.
Although I don't have an explosive cap top in my collection yet, I do have have the box for one :o
(http://ta0.com/museum/images/other_tops/exploding_top_box_1.jpg)
(http://ta0.com/museum/images/other_tops/exploding_top_box_3.jpg)
It's German and takes the cap at the tip, with a Gibbs type starter. I asked Lourens and Cyril but they hadn't seen one before, so it's going to take a while to fill up the box ::)
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Here's an interesting, but probably dangerous idea for a pyrotechnic top.... "said top consisting of a lower section having a spindle and of an upper section having a socket for receiving a Roman candle or other piece of fire-works"
Just imagine the light show: A slowly tilting modern roman candle or spark-shooter precessing in the dark! Lots of visual potential there.
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Going on Renee's patent diagram alone, I first imagined the 1890 metal pyrotechnic spinning top (PST) sleeping or precessing with an axial roman "candle" or like firework held in the central socket above the split metal disk.
Then I read the patent. Turns out that the PST also takes a pancake-like "pinwheel" firework sandwiched between the disk's upper and lower faces. The burning pinwheel would then provide a sustained rocket-assisted spin-up kicking in after the string start.
But wait, there's more. The patent envisions both fireworks going off at once!
Imagine the show in the dark. The glowing candle jet sweeps out a virtual cone of light as the loaded top precesses -- perhaps with an interlude of quiet sleep tracing out only a vertical line at some point. Meanwhile, the glowing pinwheel jets sweep out a virtual disk of light around the top disk. Like an active spiral galaxy with just one axial jet.
Guessing it would be pretty easy to get the PTA to put on a decent light show with a pinwheel alone. Question is, could the string start impart enough angular momentum to the loaded PTA to get a decent show with the candle alone?
Depends a lot on the weight and length of the candle. And with the relatively small disk radius and large loaded CM height shown in the diagram, not so sure. Spin time could be too short.
Increasing disk radius, reducing CM height, or both would help by reducing critical speed. But reducing ground clearance beneath the disk to lower the CM would also reduce scrape angle. For a given candle-like firework, you could instead use a denser metal without changing disk radius or ground clearance. That would effectively reduce CM height and critical speed without narrowing the scrape angle.
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My biggest question about the pyrotechnic top is how and when do you light it?
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My biggest question about the pyrotechnic top is how and when do you light it?
Before the string launch -- presumably with properly timed fuses. Patent suggests that roman candle can somehow light the long pinwheel fuse shown in lower right diagram. So maybe you only need to light the candle fuse.