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Patent number: 528145
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Patent number: 528145
On Jan 13, 3:16 am, " wrote:
http://www.google.com/patents?id=Pj5HAAAAEBAJ What happens here? As drawn, nothing happens. There's no mechanism to compensate for the varying chain length, and the chains are either going to bind or skip. Later proponents of elliptical chain rings have realized that; a) The sprockets need not also be elliptical, b) There does not need to be two chains, and c) There needs to be chain slack and some kind of spring loaded tensioner. |
Patent number: 528145
On Jan 13, 1:16*am, " wrote:
http://www.google.com/patents?id=Pj5HAAAAEBAJ What happens here? Dear G, Regrettably, the rest of RBT prepares to suffer because you've shown me the wonderful Google patent search. Thanks, Carl Fogel |
Patent number: 528145
On Jan 13, 6:06 pm, wrote:
On Jan 13, 3:16 am, " wrote: http://www.google.com/patents?id=Pj5HAAAAEBAJ What happens here? As drawn, nothing happens. There's no mechanism to compensate for the varying chain length, and the chains are either going to bind or skip. Later proponents of elliptical chain rings have realized that; a) The sprockets need not also be elliptical, b) There does not need to be two chains, and c) There needs to be chain slack and some kind of spring loaded tensioner. Yes, that's what I thought. I've seen the egg shaped sprockets appear and disappear over the years. The point of the patent seems to be in having a chain for both pedals. Here is a modern patent referencing this one. "A drive mechanism applicable to bicycles for increasing the efficiency of pedaling action via independent pedals with a sinusoidally varying transmission ratio. The drive mechanism achieves increased efficiency by making the pedals independently synchronized with a varying transmission ratio" http://www.google.com/patents?id=lUIZAAAAEBAJ You know of any production bike using that? |
Patent number: 528145
On Jan 13, 1:03 pm, Ryan Cousineau wrote:
In article , wrote: On Jan 13, 3:16 am, " wrote: http://www.google.com/patents?id=Pj5HAAAAEBAJ What happens here? As drawn, nothing happens. There's no mechanism to compensate for the varying chain length, and the chains are either going to bind or skip. Later proponents of elliptical chain rings have realized that; a) The sprockets need not also be elliptical, b) There does not need to be two chains, and c) There needs to be chain slack and some kind of spring loaded tensioner. Interestingly enough, c) is not true! http://sheldonbrown.org/gunnar/index.htm I'd have to fuss to figure out if the chain length is precisely constant for any position of the rings (and if Biopace vs. true ellipses matters), but this is an effective demonstration that the chain length change is negligible. -- Ryan Cousineau / "My scenarios may give the impression I could be an excellent crook. Not true - I am a talented lawyer." - Sandy in rec.bicycles.racing It's hard to tell without any dimensions, but those chainrings looked much more eccentric than Biopace. There's no way with a gearing other than 1:1 for the chain length to stay constant for two elliptical rings. I believe that the 2:1 arrangement can be lined up to avoid the extremes though. |
Patent number: 528145
On Jan 13, 1:05 pm, " wrote:
On Jan 13, 6:06 pm, wrote: On Jan 13, 3:16 am, " wrote: http://www.google.com/patents?id=Pj5HAAAAEBAJ What happens here? As drawn, nothing happens. There's no mechanism to compensate for the varying chain length, and the chains are either going to bind or skip. Later proponents of elliptical chain rings have realized that; a) The sprockets need not also be elliptical, b) There does not need to be two chains, and c) There needs to be chain slack and some kind of spring loaded tensioner. Yes, that's what I thought. I've seen the egg shaped sprockets appear and disappear over the years. The point of the patent seems to be in having a chain for both pedals. Here is a modern patent referencing this one. "A drive mechanism applicable to bicycles for increasing the efficiency of pedaling action via independent pedals with a sinusoidally varying transmission ratio. The drive mechanism achieves increased efficiency by making the pedals independently synchronized with a varying transmission ratio"http://www.google.com/patents?id=lUIZAAAAEBAJ You know of any production bike using that? No, but that patent was filed by Rotor: http://www.rotorcranksusa.com/ They're not likely to be developing that particular design, but rather filed the patent to keep some small part of it protected for themselves. |
Patent number: 528145
" wrote:
http://www.google.com/patents?id=Pj5HAAAAEBAJ What happens here? wrote: As drawn, nothing happens. There's no mechanism to compensate for the varying chain length, and the chains are either going to bind or skip. Later proponents of elliptical chain rings have realized that; a) The sprockets need not also be elliptical, b) There does not need to be two chains, and c) There needs to be chain slack and some kind of spring loaded tensioner. " wrote: Yes, that's what I thought. I've seen the egg shaped sprockets appear and disappear over the years. The point of the patent seems to be in having a chain for both pedals. Here is a modern patent referencing this one. "A drive mechanism applicable to bicycles for increasing the efficiency of pedaling action via independent pedals with a sinusoidally varying transmission ratio. The drive mechanism achieves increased efficiency by making the pedals independently synchronized with a varying transmission ratio"http://www.google.com/patents?id=lUIZAAAAEBAJ You know of any production bike using that? wrote: No, but that patent was filed by Rotor: http://www.rotorcranksusa.com/ They're not likely to be developing that particular design, but rather filed the patent to keep some small part of it protected for themselves. Locking up the 'belt with suspenders' dual chain market? -- Andrew Muzi www.yellowjersey.org Open every day since 1 April, 1971 |
Patent number: 528145
Carl Fogel wrote:
Regrettably, the rest of RBT prepares to suffer because you've shown me the wonderful Google patent search. Somebody brew Carl a pot of strong coffee. I think he's going to be busy for a while! Chalo |
Patent number: 528145
In article
, wrote: On Jan 13, 1:03 pm, Ryan Cousineau wrote: In article , wrote: On Jan 13, 3:16 am, " wrote: http://www.google.com/patents?id=Pj5HAAAAEBAJ What happens here? As drawn, nothing happens. There's no mechanism to compensate for the varying chain length, and the chains are either going to bind or skip. Later proponents of elliptical chain rings have realized that; a) The sprockets need not also be elliptical, b) There does not need to be two chains, and c) There needs to be chain slack and some kind of spring loaded tensioner. Interestingly enough, c) is not true! http://sheldonbrown.org/gunnar/index.htm I'd have to fuss to figure out if the chain length is precisely constant for any position of the rings (and if Biopace vs. true ellipses matters), but this is an effective demonstration that the chain length change is negligible. -- Ryan Cousineau / "My scenarios may give the impression I could be an excellent crook. Not true - I am a talented lawyer." - Sandy in rec.bicycles.racing It's hard to tell without any dimensions, but those chainrings looked much more eccentric than Biopace. There's no way with a gearing other than 1:1 for the chain length to stay constant for two elliptical rings. I believe that the 2:1 arrangement can be lined up to avoid the extremes though. I'm referring not to the design in the patent (which is clearly insane) but to Sheldon's bike as a demonstration that you don't need a spring loaded tensioner (or, I believe, notable amounts of chain slack) to run a Biopace ring and a round cog. -- Ryan Cousineau http://www.wiredcola.com/ "My scenarios may give the impression I could be an excellent crook. Not true - I am a talented lawyer." - Sandy in rec.bicycles.racing |
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