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    Default OT PatCVT

    Hello all.


    PatCVT

    In the PatCVT a sprocket or gearwheel (actually an idler) is intermeshed with "teeth" on both spans of the V-belt.
    The displacement of the center of the sprocket varies positively the transmission ratio:



    enabling various "modes" of operation:

    Drive Mode:
    The lever that holds the sprocket is released to pivot freely about the cross; the CVT runs automatically under the control of a variator in the one conical pulley and of a spring / torque cam in the other conical pulley.

    Sport Mode:
    Performance oriented.
    A control spring pushes the lever towards the conical pulley with the spring / torque cam; the CVT continues to run "fully automatic", but it selects shorter transmission ratios.

    Economy Mode:
    For green, quiet, reliable, comfortable operation.
    The control spring pushes the lever towards the variator's conical pulley; the CVT continues to run "fully automatic" (as in the "Drive Mode"), but it selects longer transmission ratios.

    Manual Mode:
    The rider / driver displaces "manually" the lever about the cross to select any transmission ratio from the available infinity, regardless of what the "variator / spring / torque cam" command.
    By locking the lever at a number of discrete positions, the CVT replicates a manual gear box.


    In all modes the sprocket acts as a "baffle roller" (drive belt tensioner), too.

    The available space inside the CVT of many scooters (like, for instance, the Sport-City Aprilia 250cc, below) is more than what the PatCVT needs:




    How it works?

    With the sprocket engaged with the toothed-V-belt as in the animation, the sprocket divides the V-belt in two parts (one at left of the sprocket and another at right of the sprocket), with each part maintaining its length constant.

    The move away of the center of the sprocket from the one conical pulley causes the decrease of the effective diameter the V-belt is running on this conical pulley, and the increase of the effective diameter the V-belt is running on the other conical pulley.



    The PatCVT can be used without a variator, too.
    In such a case each conical pulley has its own spring to keep its two halves close to each other:



    Such a version can be used in machines and equipment (milling machines, laths, drills, blenders etc) wherein a wide range of transmission ratios and an easy / direct control over the transmission ratio are mandatory.


    For more: http://www.pattakon.com/pattakonPatCVT.htm


    Thoughts?

    Thanks
    Manolis Pattakos

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    Two sets of tension springs (or variator tensioner)? Doesn't sound all that efficient .Hardinge's twin belt with central moving sheave requires no springs and has a similar foot print.

    Interestings idea though :-)

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    How about a descriptive title (like the sticky up top requires)
    and what exactly is this posting asking for ?

    Looks like either a sales call, or a young student copy & paste
    from Wikepedia.

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    Hello Billtodd.

    You write:
    “Two sets of tension springs (or variator tensioner)? Doesn't sound all that efficient .Hardinge's twin belt with central moving sheave requires no springs and has a similar foot print.

    Interestings idea though :-)”


    Two stages of V-belt transmission, and efficient?

    Thanks
    Manolis Pattakos

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    Quote Originally Posted by digger doug View Post

    Looks like either a sales call, or a young student copy & paste
    from Wikepedia.
    Nothing so common Doug, ..........this one spends his days reinventing the wheel

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    Quote Originally Posted by manolis View Post
    Hello Billtodd.

    You write:
    “Two sets of tension springs (or variator tensioner)? Doesn't sound all that efficient .Hardinge's twin belt with central moving sheave requires no springs and has a similar foot print.

    Interestings idea though :-)


    Two stages of V-belt transmission, and efficient?

    Thanks
    Manolis Pattakos
    yes, far more efficient. There is no unnecessary side load on the belts . The side load on an hlv drive belt is that of a normal V belt i.e. goes up in proportion to load.

    You can, for instance, easily turn the motor with the chuck on my lathe in its lowest speed setting (effectively driving the motor five(?) times as fast as the chuck). Try the same on a single belt, single spring Bridgeport style varispeed head and you will feel the load on the belt. (it is also why the bp has forced air cooling of the drive , whereas the hardinge just runs cool).

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    Hello Digger_doug and Limy_Sami

    Take a read at OT: -Asymmetric Transfer and Exhaust in two-stroke engines

    Then get back with some strictly technical objections.

    Thanks
    Manolis Pattakos

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    Hello BillTodd

    You write:
    “yes, far more efficient. There is no unnecessary side load on the belts . The side load on an hlv drive belt is that of a normal V belt i.e. goes up in proportion to load.”


    From the several millions of scooters on the roads, for some reason, none is using the Hardinge's twin belt with central moving sheave mechanism (known for about a century).


    From another viewpoint:

    Take the most advanced CVT for scooters, the electronically controlled SECVT of Suzuki (a technical analysis of which (Eindhoven University of Technology) is at http://www.pattakon.com/PatBox/SECVT.pdf )



    The SECVT adds some US2,000$ to the cost of the Burgman 650 scooter.

    Then find out its advantages as compared to the PatCVT and let me know.


    By the way, the PatCVT for scooters utilizes one only conical pulley spring (in the rear pulley, just like the SECVT of Suzuki and just like the conventional “variator” CVT’s for scooters).

    Thanks
    Manolis Pattakos

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    This falls to the one criteria that puzzles me the most, keep it stupid simple.
    I have no idea if it has been tested before and what was the out come.
    The principle is very simple but it is also very good.

    What I would love to see is some dyno data on how it works, and how much you can affect the normal drive ratio of the cvt.

    One thing I can see as a benefit using this type solution, you could engage the clutch fully from the start without slipping it much.
    Just by using short ratio from the get go.

    So Manolis, its very simple to make, I hope you'll provide some dyno sheets for us.

    Marko

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    Quote Originally Posted by Limy Sami View Post
    Nothing so common Doug, ..........this one spends his days reinventing the wheel
    What's a wheel dad?

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    Quote Originally Posted by camscan View Post
    What's a wheel dad?
    That's on next years course.

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    Quote Originally Posted by Limy Sami View Post
    Nothing so common Doug, ..........this one spends his days reinventing the wheel
    At least I find these threads entertaining enough.
    Obviously Manolis has put some time and effort for the re-invented wheels and he is not pushing any sales pitches.

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    scooters on the roads, for some reason, none is using the Hardinge's twin belt with central moving sheave mechanism (known for about a century).
    No great surprise,

    the hardinge type is expensive - two sets of pullies and belts.
    efficiency is not too important - plenty of power available , can be force cooled, fuel consumption not an important sales aid.

    The suzuki mod is really just a way of shifting the control from a mechanical (fixed after design), to an adaptive electronic/mathematics problem.

    Your variator biasing idea is neat, much simpler than the vacuum adjustment used on the Daf/Volvo cars of the 70's and 80's

    perhaps you should build one into a scooter and test it .

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    Hello Billtodd.

    You write:
    “Your variator biasing idea is neat, much simpler than the vacuum adjustment used on the Daf/Volvo cars of the 70's and 80's

    perhaps you should build one into a scooter and test it .”


    The PatCVT:



    and the PatBox CVT:



    (more at http://www.pattakon.com/pattakonPatBox.htm )

    are solution of the same problem.


    In the PatBox, an auxiliary belt and a lever with some idlers controls the transmission ratio of a conventional (for the rest) CVT.



    While for the PatCVT there is neither a working prototype nor a video, for the PatBox CVT there are:





    The first prototype (for a 50cc moped) was made and tested on the road by a third party (more at the Launch lever for hobbit solution. FINALLY! forum).


    As the maker (a third party) of the first PatBox prototype writes:

    “Tonight I went to the store.
    Coming back I had to gun it uphill to catch the yellow.
    The bike just went uphill so fast compared to my other tune I had on it.
    It is nice to let the gearing do the work sometimes, and let the revs work other times.


    Thanks
    Manolis Pattakos

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    The PatBox CVT is a poinless variation on a theme, CVT systems are already available where one pulley is mechanically varied, there's one on my 1980s Mill Drill.

    The other idea relies on a new belt being manufactured which will not lose it's internal teeth in minutes when loaded in this way.

    I notice Manolis leaves discussions where accurate debunking of his "engineering" is introduced ;-)

    The proof of the pudding is in the Patent license sales

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    Hello Nicolas.

    You write:
    “I notice Manolis leaves discussions where accurate debunking of his "engineering" is introduced ;-) “



    The previous post was mine (14/8/2017), 21 days before yours (4/9/2017).


    Only today I saw yours: “Manolis leaves discussions where accurate debunking of his “engineering” is introduced.“

    I don't.

    So, what is your “accurate debunking” of the PatCVT engineering?

    Have you got how the PatCVT works?

    Have you calculated the loads on the sprocket teeth and on the belt teeth?

    Before answering, please take a look at the same discussion at 2 stroke thread (with occasional F1 relevance!) - Page 143 - F1technical.net .

    The arguments / calculations there may help you in understanding the "engineering behind the PatCVT".

    Then, please let me know your justified objections (here or there) to discuss for as long as you can provide technical arguments.


    As for your “The proof of the pudding is in the Patent license sales”:

    The only euro-4 compliant 2-stroke engine today is the KTM EXC250-300TPI (transfer port injection) of 2018.
    The TPI patent of Rotax was filed 17 years ago, remained IDLE for 15 years (no patent license sales, at all), and is near to lapse.
    Worth to note: Rotax is an engine maker.
    Now, the TPI patent of Rotax can change the world of engines.

    So, think a little deeper.

    Thanks
    Manolis Pattakos

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    I can't believe that anyone would criticize or fault any poster for sharing such refreshing mechanisms.

    If they had come as pictures out of a book from the turn of the last century, we would all be gaga over the ingenuity and advanced thinking. Unfortunately, NO ONE HAS MADE SUCH DEVICES in the last century in order for box to display them. Like minded efforts sure, but such details as manolis shows, I'm truly impressed!

    My appreciation of your work manolis! Keep it coming !


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