Has this ever been done?

[catskin]

I am wondering if any person or company ever put a variable speed on a sewing machine?  Like the ones on machinery used to be,( now most are hydrostatic) where the driven pulley was spring loaded and the drive one had a means of pushing the outside flange  in so the pulley narrowed and the belt rode farther out as the belt was pulled in on the driven pulley. Thus changing speed.

That way you would have variable speed even with a constant motor speed.

Edited October 28, 2018 by catskin
Added more to clearify.

[gottaknow]

Not that I’m aware of. A properly adjusted old school clutch motor is an excellent variable speed motor. 

Regards, Eric 

[chrisash]

Was that not the old Daff car gearbox with belts Variomatic or something simular, I remeber the Dutch brought loads of them, then suddenly they stopped making them

Automatic without the gear changes

Edited October 28, 2018 by chrisash

[garypl]

I have a 41 year old ShopSmith woodworking machine that uses this type variable speed system.  Works well, but changing speeds by turning a crank to change pulley size does not allow for smooth and easy operation.  Speed crank is not that easy to turn, especially at low speed.

Gary

[SARK9]

I have a manual screw machine (turret lathe) that uses the spring-loaded variable pitch pulley pairs which are activated by a lever....it is not effortless to move the lever, nor is the response time particularly quick. This arrangement could have the components reduced in scale for the very light demands of a sewing machine I suppose, and overcome some of the physical effort and response disadvantages. With the other options more readily available, like VFD's, various servos, and even the antiquated clutch motor itself, this seems to be more like a proposition of "why open a door when you can just tunnel under it?".

-DC 

[CowboyBob]

With the way the servo & speed reducer work & how lightweight they are compared to this setup would be overkill on a sewing machine(esp with all the extra parts on it).BTW we had a variable speed like that on our old Massey Harris self-propelled combine that I used to run on our farm & it would eat a belt every couple of yrs,as long as your were moving you could slide the lever up & down pretty easy though.

Edited October 28, 2018 by CowboyBob

[DonInReno]

18 hours ago, gottaknow said:

Not that I’m aware of. A properly adjusted old school clutch motor is an excellent variable speed motor. 

Regards, Eric 

 

Eric, I’ve always wondered what the variable speed mechanism is inside a zero max off a fabric puller?  

[Dwight]

10 minutes ago, DonInReno said:

 

Eric, I’ve always wondered what the variable speed mechanism is inside a zero max off a fabric puller?  

 Here you are Don:  

May God bless,

Dwight

[DonInReno]

Thanks Dwight!  Wow - I had no idea that’s what was going on in there!

[gottaknow]

Love the ZeroMax. When run continuously, additional cooling is a must since they are entirely enclosed. Their endless configurations make them very usefull in a factory. They are however no joy to take apart to change a bent shaft (pretty common). 

Regards, Eric

[catskin]

10 hours ago, CowboyBob said:

With the way the servo & speed reducer work & how lightweight they are compared to this setup would be overkill on a sewing machine(esp with all the extra parts on it).BTW we had a variable speed like that on our old Massey Harris self-propelled combine that I used to run on our farm & it would eat a belt every couple of yrs,as long as your were moving you could slide the lever up & down pretty easy though.

I am not thinking of using that kind of setup. Unless they already were out there.  Was just curious if it had even been done before servos and all this more modern tech became available.  And Bob  I ran an old Massey combine many hours too.  That was one of the things that made me wonder if it had been done on a small enough scale for a sewing machine.  With the controlled pulley on the motor shaft and the spring loaded one on the machine or mounted on like speed reducers are now.

[CowboyBob]

2 hours ago, catskin said:

I am not thinking of using that kind of setup. Unless they already were out there.  Was just curious if it had even been done before servos and all this more modern tech became available.  And Bob  I ran an old Massey combine many hours too.  That was one of the things that made me wonder if it had been done on a small enough scale for a sewing machine.  With the controlled pulley on the motor shaft and the spring loaded one on the machine or mounted on like speed reducers are now.

Oh,Ok,to answer your question then,I've never seen it done on a sewing machine.

[Cascabel]

I think what you are asking about is called a Reeves Drive.   My metal lathe has one.   It works quite well, but I'm not sure it would be suitable for a sewing machine.