1921 AEC London Bus on ebay (K Type)

[Scrunt & Farthing]

I would not normally post ebay finds on here, but this one struck me as interesting.    It was brought to my attention by a friend.   Mrs Scrunt&Farthing saw me looking at it on ebay and has gone to bed shaking her head and muttering something about a new kitchen... She clearly did not recognise it as a K-Type or she would have remarked on the type enjoying a chain-drive gear-box.  Perhaps she noticed it was missing its gearbox and thus chose not to mention it.  Such wisdom.

I know there are a couple of committed bus-botherers on here (and some gents nearing the end of projects, with time on their hands), and this one is missing a few key items but nothing a good polish wouldn't put right.  

https://www.ebay.co.uk/itm/Vintage-land-speed-racer-1921-AEC-London-bus-chassis-Barnfind-field-find-flats/284236371835

 

 

 

[radiomike7]

I remember seeing inside a 3 speed chain drive gearbox some years ago, apparently they were quieter than the usual spur gears and put the casing in compression rather than tension. I don't remember how they managed reverse without reverting to spur gears but I am confident some one on here will know....

[Scrunt & Farthing]

3 minutes ago, radiomike7 said:

I remember seeing inside a 3 speed chain drive gearbox some years ago, apparently they were quieter than the usual spur gears and put the casing in compression rather than tension. I don't remember how they managed reverse without reverting to spur gears but I am confident some one on here will know....

You are quite correct RadioMike on both points.  The chain drive gearbox was designed to appease the Met Police (pre Traffic Commissioner) in respect of noise levels.  I believe reverse was achieved as you describe.   Thackeray describes it thus:  The first and second gear chain wheels were free to rotate on the mainshaft, gear engagement being achieved by sliding dogs. A pair of spur gears provided the necessary change in rotation for reverse gear.  He also quotes contemporary correspondence and a paper by A S Hill on "Chains for Power Transmission" 

Brian Thackeray's book is an excellent source, but I won't spoil the ending in case others have not read it.

 

[andypugh]

9 hours ago, radiomike7 said:

 I don't remember how they managed reverse without reverting to spur gears but I am confident some one on here will know....

You just cross the chain, obviously 🙂

(My grandfather used to say that he once tried that, when they simply could not get a motor on some equipment to reverse. I have never been sure whether he was serious, and it is now several decades too late to ask) 

 

[radiomike7]

1 hour ago, andypugh said:

You just cross the chain, obviously 🙂

(My grandfather used to say that he once tried that, when they simply could not get a motor on some equipment to reverse. I have never been sure whether he was serious, and it is now several decades too late to ask) 

 

Now why did I not think of that? Joking aside they often cross the belt when driving threshing machines and saws with a traction engine, reverses the direction and gives a better belt wrap.

[Citroman]

Or like the messerschmid car starting the engine in reverse...😁

[Ian L]

One for the Goslings here, although they would probably turn it down as there's too much to start with & not enough to make & find.

[MatchFuzee]

On the Frazer-Nash - a separate idler shaft for the reverse.