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Whilst perusing some fascinating 19th century material on chainless bicycle solutions, I happened across this drawing of the Hildick Chainless Bicycle Gear.
The Hildick Chainless Bicycle Gear (1898)
Given the main reason for replacing the bicycle chain is to obviate a messy, potentially dangerous and fragile drive system, the decision to opt for a large, open gear and all the greasy, moving parts that entails seems somewhat eccentric. In case you haven’t worked it out, the inner ring of the mechanism is fixed and the outer ring runs on bearings, something like a giant freewheel. In its favour, it looks as though it could have been retro-fitted to any standard, chain-driven bicycle.
It made me reflect on something I’d once read Dean Kamen, inventor of the Segway, say about the South Pointing Chariot invented by the ancient Chinese – a cart which, through an assembly of differentials, pinions and annular gears, would always point an indicator stick South, no matter in which direction it was driven. The odd thing is that the Chinese had already discovered the magnetic properties of lodestones and thus had a ready method of detecting North even when unable to use astronomical navigation. They had essentially reinvented the problem! Now, if only someone had pointed Mr Kamen towards the bicycle he might have saved himself a lot of bother.
To me, the most elegant solution for a chainless bicycle offered in the late 1890s was the bevel-geared shaft-drive system by Sterling and others in the USA, possibly because it looks so much like the hand-operated food mixer I remember mentally disassembling as a child. Unfortunately, it would probably have limited serviceable life due to gear wear – the bevelled teeth providing such a small point of contact that they would be unable to take the full leverage of the crank over a prolonged period – but it does offer some inspiration.
The Sterling bevel-geared Chainless Crank Bracket (1898)
What if the crank axle were a fixed worm gear so that there was more metal in constant contact with the drive shaft and hence a more evenly spread load? This after all is the chief benefit of a chain – the spread load of numerous teeth being driven at once. Would the gear ratio be too low to be practical? It would certainly take up less space in the bottom bracket…
If we revert to a chainwheel and chain, with the appropriate constraining rollers, there is no reason at all we could not have a chaindriven system which was completely enclosed in the chainstay!
Any thoughts?
UPDATE: Appears that UK company Zero Bikes have already resuscitated the shaft-driven chainless bicycle. I really should keep up to date!
UPDATE 2: OK! There’s also Dynamic Bicycles in the USA. Jings! I’m so out of touch!
UPDATE 3: Yes…and also from Beixo in the Netherlands. This post is now closed!
r:B
And another thing…
Today the BBC reported – as news – the views of motorists’ organisations to the possibility that cars may be fitted with speed limiting technology. This technology has existed for the past decade or more in one guise or another but has presumably now become economically accessible to the mass market.
I’m not suggesting this is the solution to any of the transportation problems we face today but it has highlighted yet another problem – the willingness of the BBC to give free air to motoring apologists like SafeSpeed.
These self-appointed “experts” appear to claim, among other things, that we’re all terribly mistaken and it’s actually speed cameras, not cars/motorists, that kill people. They even seem to take pride in assisting booked motorists evade prosecution on legal technicalities. The name sits rather incongruously because they seem to believe it’s safe to speed…
(photo by MonkeyBoy69)
SafeSpeed claim that speed limits “must never be set for ideological reasons” – but should presumably be scrapped for their ideological reasons…? They – SS as they like to call themselves – oppose GPS-assisted automatic speed limitation for cars and yet claim in their “manifesto” that 20mph limits in residential areas are a bad idea because “it simply takes too much driver attention to maintain 20mph”! But surely that’s the point of…oh, never mind!
I do agree with SS on one matter. Speed cameras do not improve road safety per se. They do a good job, however, of reducing the speed of traffic which, in turn, has been proven to reduce fatalities should collisions with other road users occur.
Other SpeedSafe utterances may sound arguably sane at first but, on examination, are all based on their ideology of motorist supremacy, the right of the motorist above all other road users. They even propose that compulsory road safety training of children from five years old should replace the enforcement of speed limits and “technical” traffic offences. Yeah…let’s put the onus on the kids!
Oh…and bicycles? Apparently we’re partly responsible for road deaths caused by drivers who might be traumatised by “roads narrowed in a misguided attempt to slow traffic – sometimes by the provision of unused cycle lanes“. At least that’s the implication…
And they call this “Intelligent Road Safety”. That sounds credible… something like Intelligent Design, eh?
I’m not going to waste valuable minutes of my life reading my way through their entire web site – “over 350,000 words” apparently (although I imagine a lot of them are repeated), nice claim if you’re selling a dictionary but pretty vague otherwise. Please feel free to send in any howlers you find should you venture to browse it further.
To return to my point – the BBC allowed an SS spokesperson to make unsupported claims about the safety implications of speed limiting devices in cars. Similar concerns over safety were voiced, unchallenged, by a representative of the Motor Industry Research Association. This despite ongoing joint research – in which the spokesperson is an apparent collaborator – between MIRA and the University of Leeds which, in 1998, suggested that introduction of a more rudimentary system of dynamic EVSC (External Vehicle Speed Control) could result in a 35% reduction in road traffic accidents (PDF and more detailed PDF).
This was also the experience of researchers at the University of Lund, Sweden (Varhelyi, Hyden et al, 2002 [MS Word .DOC]) whose trials of a similar system in the 1990s were very positive, arriving at the unsurprising conclusion that “those who need it most are the most negatively inclined to the idea”.
This, in turn, might explain why researchers in Finland recorded that a minority of drivers reacted negatively (MS Word .DOC), finding their ISA (Intelligent Speed Adaptation) system “very irritating and even dangerous”, expressing concern over potential “situations when there would be a need to get out of the way”. These respondents also felt “other car drivers drive very close thus likely to cause more rear-end collisions” but this – and I freely admit to speculation – may simply be an unaccustomed reaction to aggressive driving behaviour of motorists in unrestricted vehicles. There is no reason an ISA system might not also include proximity-sensing technology to prevent such “tailgating“.
More information on ISA research in Sweden is available from the Swedish Road Administration.
Have I made my point yet? I usually champion the BBC as the excellent world-beating broadcaster it surely is. So I can’t abide this kind of lazy journalism where opinion is presented as news and claims are accepted as findings.
R:B
“A bicycle made almost entirely of hemp and resin has been constructed at Alesandria, Piedmont Province, Italy. The bicycle weights about 30lbs and can carry a weight up to 240 lbs. It is hoped to use hemp and resin in the manufacture of other mechanical equipment.”
Reuters, Friday, 23rd February 1940
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R:B
