Hand Crank

[transatlantic]

I want to build my own hand crank exercise thing. the ones you'll see in the gym are large, like this :

I want to build something more like this :

I want it to be small and compact so I can attach it to one of the posts of my cage and wont stick out :

Why don't I just buy the one I posted above? They're pretty rubbish. The arm cranks are too short, which makes the exercise radius too small (far smaller than the gym ones), and the tension device is pretty rubbish too.

Wondering if anyone had any thoughts on how I could make something better?

 

[duncanh]

You could probably cobble something together using an old bike frame mounted vertically to save space: wheel below a seat, arms use the peddles. I seem to remember you can buy extra length cranks for the peddles. You can probably get a bike for free off freecycle. You could play about with gearing to change the resistance or perhaps use a variable resistance roller pressed against the wheel, like one of those indoor bike trainers. If you're lucky you might even be able to get one of those on Freecycle too

 

[bugbear]

Unless the (fulltime, professional) designers are morons, the gym ones are probably the way they are for a reason.

BugBear

 

[Racers]

They had one of the exercise bikes apart at my gym the other day quite impressive in side, a car alternator a very big resistor as a load, its going to be difficult to match the level engineering in home made unit.

If you have a power rack why do you need hand crank exercise thing?

Pete

 

[transatlantic]

You could probably cobble something together using an old bike frame mounted vertically to save space: wheel below a seat, arms use the peddles. I seem to remember you can buy extra length cranks for the peddles. You can probably get a bike for free off freecycle. You could play about with gearing to change the resistance or perhaps use a variable resistance roller pressed against the wheel, like one of those indoor bike trainers. If you're lucky you might even be able to get one of those on Freecycle too

Thanks for the ideas!

Unless the (fulltime, professional) designers are morons, the gym ones are probably the way they are for a reason.

Of course, but they're built to last with a lot of mass, and have a much higher resistance than I'd need, as well as having the resistance tied into the programs. I won't need any of that stuff or the chair/frame. So am hoping it can be massively scaled down.

They had one of the exercise bikes apart at my gym the other day quite impressive in side, a car alternator a very big resistor as a load, its going to be difficult to match the level engineering in home made unit.

If you have a power rack why do you need hand crank exercise thing?

Pete

Yeah - I'm not trying to match that level of engineering. Just something very simple and small, but with a better resistance method than the one I linked, which just uses a knob to rub something against the bearings to apply friction.

I want the hand crank as it's a really good exercise machine for me (paraplegic), I use them all the time at the gym. This will be for my 'home gym' which I use when I can't get to a proper gym.

 

[bugbear]

They had one of the exercise bikes apart at my gym the other day quite impressive in side, a car alternator a very big resistor as a load

Chris Hoy peaked at 2700W. :shock:

Wiggins was putting out a sustained 450 watts on mountain stages.

"adults of good average fitness average between 50 and 150 watts for an hour of vigorous exercise."

(ref: https://en.wikipedia.org/wiki/Human_power)

So it sounds like the resistor/heatsink would need to be spec'd to handle at least 200 watts.

BugBear

 

[novocaine]

a lot of cycle trainers use an inverted fan to apply resistance (same fan as used in most car heater systems), it isn't adjustable but changes the harder you pedal (as it's pushing air into it's own volume which it can't clear so pressure increases inside thus the resistance increases), you can add baffles if you want to change the resistance, or they use magnetic resistance. can you weld? if so then extending crank arms is easy enough (steel crank arms that is) or using aluminium arms with some form of over tube and pins to make them adjustable might be a good idea. what ever you do, you will need to move the resistance element away from the crank as it will be to wide to fit between them. so an old bike is a good start, then look for a fan from a car heater if you want air resistance, linked with a chain drive so for ease of use a rear hub and the fan attached instead of a rim is a good appraoch. do you use a hand bike already? if so, just stick the front wheel in a cycle trainer lol.

 

[Sheffield Tony]

They had one of the exercise bikes apart at my gym the other day quite impressive in side, a car alternator a very big resistor as a load

Chris Hoy peaked at 2700W. :shock:

Wiggins was putting out a sustained 450 watts on mountain stages.

"adults of good average fitness average between 50 and 150 watts for an hour of vigorous exercise."

So an alternator and a 200W dump load. Then the machine plugs into the mains to power the performance meter, and an air conditioner keeps the room cold by pumping the heat outside. Meanwhile, the pool in the next room is heated by mains electricity/gas ... this is all insane.

Or how about one of these ?

 

[Cheshirechappie]

*Chuckle*

I was going to post earlier with something along the lines of, "Sell the washing machine and buy a mangle", but rejected the idea because it did seem a bit snarky.

I note that the OP is paraplegic, so there is a logic in his thought process about exercise, but for most of us it does seem rather ironic that having spent the last couple of centuries inventing devices to take the drudgery and labour out of daily life, we now have to invent devices for no other purpose than to deliberately expend the energy we've saved.

Maybe a bit of vigorous sawing or hand-planing now and again might have some merit?

(Why does the !*?*$* spelling corrector on this site always turn the word 'planing' into 'planning', necessitating an edit to correct? Grrr...)

 

[bugbear]

I note that the OP is paraplegic, so there is a logic in his thought process about exercise, but for most of us it does seem rather ironic that having spent the last couple of centuries inventing devices to take the drudgery and labour out of daily life, we now have to invent devices for no other purpose than to deliberately expend the energy we've saved.

Let's have a moment of silence for all those Americans who are stuck
in traffic on their way to the gym to ride the stationary bicycle.

--Earl Blumenauer

BugBear

 

[Sheffield Tony]

*Chuckle*

I was going to post earlier with something along the lines of, "Sell the washing machine and buy a mangle", but rejected the idea because it did seem a bit snarky.

I note that the OP is paraplegic, so there is a logic in his thought process about exercise, but for most of us it does seem rather ironic that having spent the last couple of centuries inventing devices to take the drudgery and labour out of daily life, we now have to invent devices for no other purpose than to deliberately expend the energy we've saved.

Maybe a bit of vigorous sawing or hand-planing now and again might have some merit?

(Why does the !*?*$* spelling corrector on this site always turn the word 'planing' into 'planning', necessitating an edit to correct? Grrr...)

Ah, my sincere apologies for any offence caused, I didn't spot that detail. Edited to tone down snarkiness

Gym equipment remains a puzzle to me tough. I confess that I used to use a local gym, for a good few years after giving up rowing. I gave up when the relatively sensible equiplent was replaced with stuff with monitors with cartoons of you racing against another cyclist, rower ... I still can't understand why they draw energy from the mains, rather than generate it. Ultimate dummy load - doesn't heat up the gym, and get paid feed in tariff.

 

[Racers]

Turning a big fan would be the best way to provide resistance, its what the concept" rowing machines use, any form of friction will change resistance due to expansion as the parts heat up.

You could do a search on Ebay for a second-hand one.

Pete

 

[transatlantic]

Gym equipment remains a puzzle to me tough

I do agree. Finding a good sport or walking/running/cycling to work (if possible) makes far more sense than paying to use a gym. You save money and get fit in the process. Unfortunately, thats not very practical for me, and I just don't enjoy sport, so this works for me. I bloody hate going to the gym to be honest, and want to be in and out as quickly as possible, so I try to find exercise equipment that will allow me to do short burst of high resistance, such as weights and hand cycling. I really don't get on with the 30+ minutes of slow exercise (per machine) I see other people doing.

Buts gyms do have their place. Especially for targeted exercise, and convenience/comfort.