Linear Actuator for Continuously Variable Transmission (CVT)

I use a laptop & from time to time was frustrated by losing all or parts of posts. I finally figured out my hand was brushing the mouse pad as I type & that I could retreive the missing comment with the back or forward buttons...

You can compose on word & copy/paste the entire contents in the CR4 reply box

You should edit your profile:

Off-Topic Comments

How should off-topic comments be shown?

I want off topic comments to appear like any other comment

You'll find that there aren't that many off topic, usually just a bit of cross talk or chit chat... many time better than the actual discussion

I feel your pain on the life/health/finances front...

I don't have a solution, I tried what you are attempting [bootstrapping] & it was going well until I[we] got tripped up by circumstances & bad timing. I too had picked what I considered to have the best chance of success, hoping to built on the credibility gained. You have at least outlined & backed up you potential solutions, haven't you?

The patent process only provides protection equal to your ability the afford legal representation. Venture capitalists are held in similar esteam to lawyers & whale shit

You need a partner in which you can trust whose skills compliment your own. I don't have a suggestion in that regard. These are all common themes, often repeated on this site.

One more shot on my twist on the original problem... 2 racks, one for neutral positions & one for engaged positions. I would consider blinks opinion of the actual number of ratios needed to be correct. Limiting to say 20 would help redefine the problem to a more manageable level. Your short term goal is to have a working prototype to shop around.

Venture capitalists are held in similar esteam to lawyers & whale shit

That's pretty insulting to whales.

Hi PackRat et al,

I also have wondered about the durability and wear of such spring loaded detents to locate the shifter mechanism. Others have addressed it and I have to agree them with proper design and utilization of the correct materials I think it will do the job and will most definitely be a LOT cheaper than any active sensing and feedback self correcting locaters will be. As I have stated, there is virtually no sideways forces on the shifter mechanism in neutral and VERY little even under the heaviest loads and under full power.

A spring loaded mechanism would be a lot more positive and reliable than any such 'gravity' mechanism. As you can read in my reply #76 & ~ 78 or 79 I'll utilize a likely use a cylindrical plunger with a hemispherical end instead of a ball bearing that will be able to seat itself deeper and much more positively than a simple ball bearing would. The small, light and inexpensive spring loaded positive locators and grooves would be much more reliable than any such gravity mechanism. In order for the gravity mechanism to work reliably it would have to be VERY large and heavy which isn't warranted and there is no room for. Also jarring during operations due to road conditions etc would make these unreliable.

I'm familiar with the desmodromic valve trains and it is definitely heavy 'over kill' in this application. There is nowhere near the type of forces, accelerations and deceleration that requires any such mechanism and it would be way to complex and expensive to utilize.

Thanks for the reference to the OnLine cataloging of the wide variety of leavers, slider and crank mechanisms. I have encountered such things before and have a number of books of similar devices in my technical library myself.

On this note decades ago I found out about a book that was a comprehensive compendium and cataloguing of a VERY wide variety of designs and (theoretical) possibilities for internal combustion engines. It took me ten years track one down. I am in western Canada and there was a copy of it in an Ottawa branch of the Canadian Research Council. In conjunction with a technology institute in the Vancouver, BC area I managed to get it sent out to the BC tech institute for me to look at. I was allowed to take it and look at it for 3 days! I photocopied the whole thing, but at the back of it there was about a 25 (double sided0 page listings/array of catalogued and classified possibilities of mechanism for IC engines. Out of necessity it was in full color. Alas I had no access to any such color photocopy machine. The great IC engine design that I have come up with that is truly outstanding in many ways and has a LOT of advantages to it including being a realistic contender to make mass flying (urban) personal transportation vehicles a reality was not included in this very comprehensive cataloging of such IC engines.

Please don't take these as a personal invalidations because they most definitely are not. I appreciate your ongoing insights and input so please continue to be involved with this and share anything and everything that you care to.

Regards, (< 8)

Doug

I don't know if you are hooked up to the various newsletters or global spec data base?

I saw this today:http://www.drives.co.uk/fullstory.asp?id=2729

There are a couple of problems with this. They first one is wear, primarily of the grooves, and the weakening of the springs and the cylindrical followers/positioners' that they operate within.

Ball detents are used on essentially every manual transmission, car truck and motorcycle. If you can possibly use such an arrangement it would be far less costly and more reliable than the linear transducers and actuators used on CNC machines (less costly by about 1/100, 1/1000 etc -- i.e. far more than one order of magnitude.)

Remember that, in practice, there is no difference in engine efficiency between a 5 speed manual gearbox and a well-designed CVT (if both operate at about 95% efficiency when not being shifted). Audi's tests of about a decade ago showed this. The breadth of the sweet spot (best BSFC) in engine efficiency has continued to increase (largely because of variable valve timing), so that an accurately-shifted transmission of either type can keep the engine at its optimum (for a given load condition). Consider that the Volvo turbo engines have had a perfectly flat torque curve from 1500 - 4500 for about a decade. (With most engines, the BSFC curve at a given throttle setting is roughly the torque curve flipped over.) So even with only 5 speeds, there is no need for a 4 1/2 speed or a 2 1/2 speed: the increments are already sufficiently small. (For acceleration performance alone, there can be a slight advantage to always running the engine at exactly its HP peak, but even there, the difference is very small.)

Back when I was racing motorcycles, 12 speed transmissions were necessary in 50cc GP bikes because the power band was so light-switch-peaky, but even flat out racers in slightly larger classes did well with 5 and 6 speed boxes. Modern car engines are about an order of magnitude less peaky than those old racers. 6 speeds were first introduced in production bikes with the Suzuki X6 Hustler (a 250 twin) in 1964 or so, and still, 6 speeds is the standard in the 600 cc sport bikes that are essentially road racers with lights.

The Porsche (etc) double clutch 8 speed transmissions have the advantage of lightning fast shifting, but the overall efficiency (of the engine transmission unit) is little different than a five or six speed. The improvement in lap times has as much to do with the slight power delays at each shift (in a conventional trans) adding up through the many shifts in a lap as it does with keeping the engine in a very narrow rpm range.

So... if your transmission is to compete with modern transmissions it will need to do so primarily on cost, and secondarily on function. Reliability is simply no longer an issue (other than when design flaws are incorporated -- which happens far too much). No one is screaming "If only we had more reliable transmissions!" For example, I could be a potential buyer for your transmission, but for my application, a 4-speed transmission works as well as a CVT, in terms of overall vehicular efficiency. The deciding factor for me would be the overall cost, including the shifting mechanism (which would need to be automatic, for marketing reasons).

Therefore, if you can use a simple detent for location , and if a simple fixed-stoke actuator can nudge the transmission from one ratio to the next, then I'd forget about linear actuators, precise feedback, etc. Properly designed, a detent spring never wears out. Consider engine valve springs, which are routinely flexed more dramatically (re the torsion angle per unit wire length) over billions of cycles. A spring design firm (Diamond Wire in Pittsburgh is good) can tell you in a couple minutes the spring characteristics required for a detent spring to be able to last for 100 years, assuming a cycling rate of only twice per second (which would suggest 20 shifts on the way to 60 mph in 10 seconds -- which is too many shifts). In the same 10 second period, an engine, running at an average of 2500 rpm, will flex each valve spring 21 times per second, or 210 times in 10 seconds.

Ball and grove wear? Essentially none, given correct material selection, hardening, and lubrication. A ball going into a detent has a very easy life -- it is far less stressful than a the life of a ball in a ball bearing.

Keep it simple. If you can deliver a 10-speed transmission that offers instant shifts but does away with the astounding complexity of the Porsche style double-clutch transmissions, you've got a winner. Any more than ten speeds are useless, other than in special cases (such as haul truck that has to creep well, but also go pretty fast).

In the auto manufacturing as in many manufacturing businesses they try to keep the manufacturing costs as low as possible but actually work at making the repair costs higher.

Auto manufacturers have to pay for warranty claims, so the successful manufacturers (e.g. Toyota) have low claim rates and low claim costs. The same design decisions that make cars faultlessly reliable through the warranty period also make them highly reliable afterwards. My auto trans in my Honda van has never been apart in 200,000 miles, and I would be completely shocked if the manual trans in my other Honda required any attention at all before 300,000 miles. It has been a while since I consulted for Ford (back when they said "Quality is Job One"), but back then they were struggling just to make stuff that worked right throughout the warranty period, let alone trying to figure out how to make a piece last for 100,000 miles but fail at 101,000.

Imagine the complexity and cost of first getting your transmission to work reliably and then having to go back and figure out how to make pieces fail reliably and predictably.

Hi Blinky et al,

Please see submission # 76 first.

I'll use a ball nosed (hemispherical) end mill to either mill the slots or perhaps just even use the same cutter and just put small round indentations in the positioning strip. As I said I may also 'mirror' it and there would be both spring loaded locating mechanisms and there complementary locating spots on both the moving and the stationary parts; though very minor inaccuracies in such a design could very well result in it being less positively located than it would be otherwise. Another option and the one that at this point in time I'm inclined to use would be not to mirror it, but to put between 2 to 4 such spring loaded positioning plungers for each locating groove. There is also the possibility of not just using one 'locating groove' positioning it, but a pair of them, most likely with more than one spring locating plungers in each groove. In this instance I would 'stager' the spring located plungers so that they did not locate in the same spot in the grooves of the locating strip, but lodged into a different location along the strip, thus the wear would be distributed by half. This arrangement would also help ensure better accuracy over a longer period of time. Though as I mentioned before, I have to strike a balance between locating the shifter mechanism firmly enough to be effective and reliable, but not so stiff that the motor will be able to disengage it to move it to the next position. Still, a lot of more lightly loaded plungers is a better overall arrangement than just one or two spring located There is the problem of interference from machining inaccuracies in this design as well, but that would only be a problem in manual fabrication by myself in prototypes, but that would be sufficiently accurate enough for prototyping R&D.

It sounds like the 50cc racing motorcycle you are referring to was a 2 stroke and with the type of designs they use are very 'peaky' and have a very narrow power band. A more highly tuned racing engine would be even more so.

Though the one instance that you sight of there being no advantage to having dozens or even hundreds of possible 'gear ratios' that are both much more closely spaced and have a much broader range as well may very well be true in this one instance. But taking a very wide variety and implementations into account I can't say that I agree with you as this being 'comprehensively' and generally the case. If it were, there would be no such hybrids that add considerable complexity and expense in order to keep the IC engines operating within a very narrow speed range were they are significantly more efficient and with a lot less pollutants. I think that if one had a book that was a cataloguing of hundreds of speed versus power/torque outputs and just 'fanned/flipped/ though them like it was a sequential animation book, you would find that this is most definitely not the case. Also there are more and more small mass produced cars with IVTs in them for very good reasons. Also I don't think that you are taking into account an engine designed specifically to maximize the advantage of such a IVT or CVT as opposed to IC engines that are made with the broadest, flattest power and torque vs speed output curves just because they DON'T have any such transmissions that they are going to be operated with. In essence, you are comparing apples with oranges as opposed to taking into account these very significant design factors and compromises made just because there are only a few widely spaced gear ratios with a limited range.

Though we all know what we are referring to, when there are no actual gears involved, I wonder what the correct terminology would be as opposed to using 'gear ratios'?

Likewise, what is the metric equivalent of 'mileage' (M/G, MpG, Miles to the Gallon)?

Regards, (< 8)

Doug

[]pHi Blink,

The CR4 bot says that you posted # 98 in response to my #97 submission, but when I try to access it with by clicking on the link to your latest posting, or searching for #98, it doesn't and can't access it.

Would you mind posting it again thanks?

Regards,

Doug

Hi Doug you will find it at the bottom of the page - you have to click on the + sign to expand it.

If you're still stuck, click here.

Hi Doug,

My post was more-or-less off topic, being a series of random thoughts not relating to linear actuators specifically, so I voted myself off topic (which gives me 5 "off-topic" votes, and minimizes my post). To maximize such posts, you click on the little plus sign in the upper right corner of the gray rectangle standing in for the post.

The idea of voting yourself off-topic is mainly that if someone (later) is searching through threads looking for info on linear actuators, if a bunch of the posts are talking about invention and prototyping issues more than linear actuators specifically, that makes it hard to find the linear actuator info.

Ordinarily you can also click on the link showing the post number, as I think you tried to do. This opens a new window, with that post alone, so might be stopped by your browser if you have it set to block pop-ups.

If you respond to an off-topic post, your own post defaults to off-topic (5 votes) too... although you can change that prior to posting it, by unchecking the box before "Yes, this comment is very likely to be considered to be 'off topic'. "

Link..

Hi Kyzine,

Your Posting and the link are SNAFUD, please try it again thanks.

Doug

Try this

Thanks JD, it was fine - then I guess it wasn't, but you got it - good. tar

Hi JohnDG and Kyzine,

I've just given both of your catalogues some quick searches. It's obvious that you have a wide variety of solutions for a wide variety of applications.

The timing belt drives are out for obvious reasons, though the purely mechanical ones are not.

What do the smaller mechanical linear actuators have in the way of active linear position sensing, feedback and correction mechanisms?

Think you have any that are in the ball park for my needs?

If so, please post the references for me.

Regards,

Doug

Hi JohnDG and Kyzine,

Cost effectiveness is a VERY important factor here. I think that these would likely be too expensive an option and unlike a lead screw or a feed rod on Lathes, these lead screws would be constantly be exposed to a lubricant with very fine metallic particles in them that will lead to increased wear rates. Though I am very well aware of how dirty lead screws on manual lathes usually are, the lead screw is rarely used except for threading. Also, it is not constantly bathed in abrasive particles. Even then, relative to the life of a lathe it does not take long for the half nuts and/or lead screw that are used for thread cutting to become quite worn and sloppy. The machinist has to take this into account and utilize appropriate techniques to ensure repeatability in order to cut threads of acceptable quality and within tolerance limits. The feed rod is used for all cutting operations which is what lathes do most of the time.

In my application I need to be able to mount the shifter mechanism directly to it and there is no allowance for any rotary movement of it at all. I don't know how much of this you have read, but the linear locating is very critical and the 'nut' would have to be both self adjusting for wear and perhaps be square in cross section that so that it could run along a milled groove to keep it from rotating and so that they shifting mechanism could be mounted directly onto the 'square nut' in linear motion. I doubt that this would be sufficient to prevent the nut from rotating at all though of course the design factor is significant in this. The slot could be very deep with three sides of the linear nut running very deeply within it and almost completely 'submerged' in it. Woodruff keys running in a milled slot is another possibility either with or without the square nut running in a milled slot in the casing. Likewise there is no tolerance for movement of the 'height' of the nut: ie it being lifted in and out of the groove by the lead screw etc. The forces required are very minor, and space and volume are minimal so regardless of what mechanism is used, it has to be quite compact. With the lead screws mechanical advantage, I would likely only need one that was about ½" in diameter and lengths of between 8" ~ 16". The linear accuracy tolerance is very high: ±0.005" with 100% repeatability over an extended life time. The spring loaded locating plungers that extend into machined locater spots or grooves being referred to in this discussion thread, especially in about this part of it could be incorporated into the square nut though. If using this sort of passive mechanical linear locating system, as with other linear solutions; some linear play, sloppiness and movement would be acceptable and even desirable within limits. But again, there is no tolerance for any rotational movement of the nut at all.

Thanks for your input, I welcome more of it. (< 8)

Regards, (< 8)

Doug

Hi Doug, ball screw systems are preloaded, so 'zero backlash'. The rods and nut races are quite hard (like a ball bearing) . Positional accuracy is virtually absolute, given the expansion coefficients of rod vs driven assembly are the same. I.e something like 0.005 mm "repeatability" is 'common' in CNC machines. (0.005 mm = 0.0001968")

Encoding can be done on rod, or drive, or on driven part. However the ball screw pitch is coarser than it first appears and the very low coefficient of friction, means they will go backwards under load, so you need 'active' encoding feed-back or motor brakes to hold a station.

They like dirt as much as a regular ball bearing. There are seal and wiper options.

Thompson is first google on the net I got. You should also look at INA and THK and....

Overall I think you are over-training on the accuracy and life aspects of this.

A car has a service life of around 6000 hrs = ~ 2.2 years for a production machine (which is still "as new").

Cost? Doing once and properly is always cheaper.

But these things exist in a range of printers and similar - try the tip?

They may be the 'soft' and/or Russian ones, but printers are way more accurate than 5 thou. You may also score all the ancillary junk to run it.

Keep the major rod force in 'pull', and quite a tiny one is all you need.

OOO XXX

Kz

Hi Kz et al,

I have no interest in getting into manufacturing these myself, only in licensing them. Thus I could utilize such new off the shelf items like the industrial feed rods etc. But the Automotive industry has huge very effective blinders on when it comes to solutions from outside of their own organizations and industries. So I'm doing the best I can to come as close to a very cost effective final production model so that when the suits are taking a first look at it they don't look at the two sophisticated active industrial linear actuators that are worth a few hundred bucks each and thus immediately dismiss it as being way too expensive to manufacture and turn around and walk away. Mind you with the auto manufacturers all being turned on their heads recently with the downturn they may, and should be open to new, different and BETTER ideas. One great advantage of this CVT over and above the immediate ones of it being a CVT with a LOT more closely spaced gear ratios over a much wider range is that it's design is very simple and elegant with a much lower part count and considerably less (very accurate) machining to make it. The only actual gears in it will be an idler for reverse. I'll be very surprised if it couldn't be massed produced for about ¼ ~ 1/3 of the cost of the types of automatic transmissions that have been in use for decades. It requires no new technology or machining and manufacturing tooling or processes. As a machinist that has worked on a lot of very old, very worn out manual machine tools, I'm only too well acquainted with the 'work around' techniques of always working from the same direction to keep the repeatable accuracy in place. But it is a reality of this mechanism that it WILL be constantly reversing travel direction. Though on here I've worked this aspect through and because of the very low motive force required and almost negligible sideway force vectors while operating, I have come to the conclusion that just some passive spring loaded plungers and detents can eliminate the need for the very high accuracy active components.

As you may have read, the forces required for the shifter mechanism are very low, so thanks for the tips on scrounging old printer drives etc, the biggest problem with this may turn out to be getting the source code or hacking it in order to utilize it. This is starting off from a shoe string budget and I don't want to waste a considerable amount of time climbing the specifics of the learning curve for the scrounged printer mechanisms, drive, positioning and feedback etc. If I had to learn Russian on top of it to do it we would all be flower food before this ever happened. As it is, and likewise with my very compact, versatile and simple engine design that shares all of the same advantageous of this CVT design, they should of been shown around about 5 years ago or more. Though obviously the timing belt wouldn't stand up for long in R/L service, just the fact that it can be made to work with something that is now a very mature technology and just seeing it work with such small, low powered parts that were scrounged for almost nothing could actually be a marketing advantage. I would point out that obviously they wouldn't use a timing belt for it, but if it works with this, then…..

FYI: For the R&D and demo models I'm just going to fabricate a suitable sized metal box made out of steel plate and welded with bolt on bearing end plates, access/covers etc, stress relieved (oven and freezer) and machined. I'll have to do a lot of grinding to make the demo models presentable as it is a toss up which is worse: my OxyAcetelyn or welding skills. As my welding instructor in my machinists training observed: "Well Doug, it looks like it has been hit by a low flying cow, but it will most definitely hold together!" LoL Alas, sad but true (< 8) I'll likely put a piece of Plexiglas or similar as the removable top for the demo model, including when it is running hooked up to and operating on an engine dyno.

Regards and thanks for your input and assistance., (< 8)

{p]Doug

Hi GarthH,

When I am looking at the specs for sensing distances, there seems to be different conventions utilized to specify the 'sensing zone'. Some of them seem to be just the proximity of the sensor to the locater that specifies how close these 2 elements have to be together before they start to sense each other. In other instances it seems to be the overall linear travel distance of the shifter 'saddle'

In regards to the clutch I have a simple elegant design in mind that in effect is an 'automatic' mechanical manual clutch that doesn't require any hydraulic cylinder, lever, actuator etc to operate it. I'm not going to say too much about it on here for the moment until I check out the patent status of it.

Thanks,

DougRH[i

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Kyzine,

Thanks for the info, I'll check them out

Regards,

DougRH

Hey Doug,

Getting a feel for the area of your mechanism, without digging into your potential propriety "secrets". If I understand it the indicator could be spring loaded, but then it might not have a long enough life cycle because of lose of spring tension over time?

What's the possibility of eliminating the spring and using a dense enough follower that would rely on gravity? Using enough clearance in the followers sliding contact surface to prevent it hanging up? Or any combination of the following:

a simple advance rotating mechanism similar to the valve train on an engine, can't remember the make, that would rotate the valve during it's operation to keep the valve/valveseat surface clear.

A desmodromic type valvetrain,, adapted for this application. In a engine , the cam would have two lobes, one to lift the valve ,one to close it. Some had a very weak additional spring on the closing side. If it was incorporated in the initial design stage,maybe it could have constant mechanical force keeping it located, gravity or springs not neccessary . Like a small walking beam with pivoted, sliding followers on each end. Visualize roller, cam followers on either end, fulcrum in center.

in Heckler&Koch rifle, the chamber that contains the cartridge is fluted, to prevent failure to function, regardless of debris/gunk buildup.

Packrat

something intriguingkinetic

Quick reference desmo

Hi PackRat et al,

I also have wondered about the durability and wear of such spring loaded detents to locate the shifter mechanism. Others have addressed it and I have to agree them with proper design and utilization of the correct materials I think it will do the job and will most definitely be a LOT cheaper than any active sensing and feedback self correcting locaters will be. As I have stated, there is virtually no sideways forces on the shifter mechanism in neutral and VERY little even under the heaviest loads and under full power.

A spring loaded mechanism would be a lot more positive and reliable than any such 'gravity' mechanism. As you can read in my reply #76 I'll likely utilize a cylindrical plunger with a hemispherical end instead of a ball bearing that will be able to seat itself deeper and much more positively than a simple ball bearing would. The small, light and inexpensive spring loaded positive locators and grooves would be much more reliable than any such gravity mechanism. In order for the gravity mechanism to work reliably it would have to be VERY large and heavy which isn't warranted and there is no room for. Also jarring during operations due to road conditions etc would make these unreliable.

I'm familiar with the desmodromic valve trains and it is definitely heavy 'over kill' in this application. There is nowhere near the type of forces, accelerations and deceleration that requires any such mechanism and it would be way to complex and expensive to utilize.

Thanks for the reference to the OnLine cataloging of the wide variety of leavers, slider and crank mechanisms. I have encountered such things before and have a number of books of similar devices in my technical library myself.

On this note decades ago I found out about a book that was a comprehensive compendium and cataloguing of a VERY wide variety of designs and (theoretical) possibilities for internal combustion engines. It took me ten years track one down. I am in western Canada and there was a copy of it in an Ottawa branch of the Canadian Research Council. In conjunction with a technology institute in the Vancouver, BC area I managed to get it sent out to the BC tech institute for me to look at. I was allowed to take it and look at it for 3 days! I photocopied the whole thing, but at the back of it there was about a 25 (double sided) page listings/array of catalogued and classified possibilities of mechanism for IC engines. Out of necessity it was in full color. Alas I had no access to any such color photocopy machine. The great IC engine design that I have come up with that is truly outstanding in many ways and has a LOT of advantages to it including being a realistic contender to make mass flying (urban) personal transportation vehicles a reality was not included in this very comprehensive cataloging of such IC engines.

Please don't take these as a personal invalidations because they most definitely are not. I appreciate your ongoing insights and input so please continue to be involved with this and share anything and everything that you care to.

Regards, (< 8)

Doug

Hi Doug,

I appreciate you replying.

I'm just throwing out ideas and in no way am I offended if none of them stick to the wall. Don't want to be a distraction to your endeavors, enjoy reading this thread, I hope you advance to the patent/demonstration model phase so we all can check it out .

Hardwood sounds good, or machinable wax, but aluminum might convey more "gravitas" for the demo model.

Keep at it.

Pack

The aluminium is a good low cost choice because of the very easy machining but it will still be very accurate and durable to stand up to some actual usage. I'll use a fairly soft and highly malleable aluminum so that I can also use it as a 'stress, forces and wear indicator' running it for a while and see just exactly how and where it distorts and wears and what and where I have to focus on to improve it.

'Quasi' (non) destructive analysis and testing.

Although I did not participate I followed the evolution and I dare make a comment:

- according to what was written it will NOT be economical to have too many "steps" since the gain will not compensate the complexity, your goal being the lowest possible cost/price the number of steps should be maintained to a minimum. My estimation is 10..12 since the engine curves are quite flat. With 20 you increase in an important way the complexity but I doubt that decreasing the step from 8..10% to 5% will bring a gain such that the cost difference will justify it. I have no doubt that you thought about wear and maintenance and you will agree that more components increase the failure risk and the maintenance cost.

- the solution with mechanical indexes is a good one provided that you have still a signal for every position in order to have a situation recognition for the control. It is good because there is no more need for the control position since the mechanical index takes care of this requirement, it is enough for the control to bring the "slider" in a position where the mechanical index can be active. This way you can use lower cost motors for the movement since you do not need the motor neither to give the precise position nor to maintain the position. It will be enough to have a DC normal motor which stops when a signal from the target's sensor comes and the mechanical index brings the slider exactly in the wished position since no more torque is applied.

- the steel ball as indexing element is good for several reasons: cost/quality very low, high wear resistance even in polluted environments due to very high hardness (<HRc62), due to its physical property (magnetic) it can be the target for the position sensor, its holder can allow a "roll" so that wear is not on only one spot.

- the motor has to be strong enough to bring the indexing element out of the index grove when position is changed. This implies a good choice for the grove slope so that from one side the position is hold against disturbances and the force to leave is within limits.

Combining technologies and ideas I think that you came to a very simple and cost oriented solution.

Good luck.

Sorry to everyone who has put so much in so far for not having read every word (I have a very short attention spa_{was that a skwrl ?...}).

Quick thought springing from your post (nick name): a combination of the rack & detent and a DC gearmotor driven cam (to lift the detent against a spring) with a synchronised Geneva-type mechanism (to advance the rack 1 tooth per rev) may work, if it can be made to operate quickly enough for rapid large ratio changes.

Absolute position feedback wouldn't need to be either very precise or accurate - a simple linear (or geared rotary) encoder should fit the bill.

No worries John,

It's pretty lengthy and involved and has gotten off topic in places and I tend to be quite verbose. It's not like I am going to withhold your paycheck for not keeping up on your volunteered assistance, which I DO appreciate.

I tend to agree with you that the one rev clock mechanism will likely be to slow. If it was made to go fast enough to do the job the inertia would start to cause more headaches than it solves. I won't need any active solution to lift up a pall, there really will be no sideways force vectors of any significance if the shifter mechanism is designed and fabricated properly. Also you have to remember that it will be in almost constant motion including reversing the direction of travel constantly. I'm pretty well decided on using a passive slightly grooved strip and 4 spring loaded detents regardless of what else I do. I'm not an engineer but have decades of working with, designing 'solutions' and creating them from scratch, fixing up other's SNAFUs, repairing and fixing manufacturing defects, done a lot of varied repair work including mechanizing, machining, fabricating and welding etc and some millwrighting so I do have a good feel and sense for keeping things balanced, though I do tend to overbuild things. But getting one aspect of something out of proportion can create so many other problems that then have to be coped with and it just snow balls. If you haven't encountered it yet, the 'rack teeth' are likely only going to be ~ 1/8" deep at the most.

Though I know the basic concepts, I don't have much experience with servo motors, stepper motors, active encoders, positional sensor and feedback correction systems; but frankly the detents will do the job just fine for the demonstration prototype and likely for the production model as well. So the linear motive force and mechanism is not going to have to be REALLY precise, just get it into the ball park and have just enough free movement to allow it to be properly mechanically located and seated but not so much that it misses it. If I get it to tight I'll just bring PackRat in to 'loosen it up a little'. Don't force it eh PR, just get a bigger hammer! LoL

I'd prefer to stay away from gears for the linear actuators as likewise the finicky tolerance issues that are always present with gears. If I can find a low cost linear actuator stepper motor or encoder combo I'm open to it, if not it will be the 'steel belt' of some sort and a couple of pulleys. If I utilize a cable, I can even use a grooved pulley with a 'threaded circumference' for the cable to accurately to always seat into controlled positions. If I can get enough 'traction action' the thin (light spring) steel band that the generic Guru 'NickName' suggested. I'm not opposed to a prefabricated linear actuator, I just don't have enough firsthand experience to say: 'Yep I know exactly the type and one that will do it' Before I do get down to drawing up the actual design I'll get it nailed down precisely so that if I have to make some slight adjustments and compensate for a slightly different incremental movements to accommodate the stepper motor or whatever I end up using then I can and will do that. If I don't find a suitable, reasonably priced off the shelf solution, I haven't decided on the exact type of setup for the linear moving part to run in. I'm thinking that if I'm smart and careful enough I may get away with really low balling it with some cold rolled steel tubing, channel or angle iron that will require little if any machining at all. Time will tell. The suggestion of scavenging the complete mechanism off of a wide commercial (blueprint) printer is very attractive for a lot of obvious reasons.

None of this is going to start manifesting until money issues get handled one way or another and I'm open to collaborations, corporate or more likely at this stage, sweat equity partnerships or ??? If I get a 'business type' involved, which I need, on a sweat equity basis to put together a good business plan and perhaps find some outside financing, but frankly at this stage, I'm not willing to give up as much as I would have to in order to bring an 'angle/venture capital' partner in and give most of it up to them. I should be able to generate some substantial and significant enough capital to get it underway and have something concrete that can then be leveraged with government grants etc. Magna International, the major auto parts manufacturer is cooking up a deal with the federal government to pick up some dying auto manufacturing plants and equipment cheap and bring a whole new concept on stream for designing and building personal and light commercial and industrial vehicles. I SOOOOooooo much want to draft up some substantial correspondence and say to them: Hey, look at this CVT and engine I've got. I haven't brought this up before, but I'm fairly certain that I have a significant development that will make mass produced electric vehicles a reality as well as they will only need a couple of hundred pounds of batteries which is equivalent to an engine. This cuts down the battery pack by a few hundred to a 1,000 pounds of dead weight which further reduces battery requirements which translates into a lot longer range and less power requirements regardless of what the source is. This technology is applicable to many other things as well. The greatly reduced battery requirements cuts down the huge volume that they currently leaves no room for anything else in a vehicle and thus it would not be hard to adapt current major body styles to utilize these. They open up a lot of options that aren't otherwise possible, including a realistic mass produced flying (urban) transportation vehicle which would cut the urban transportation infrastructure costs VERY substantially. And after that, there may be things that will make all of these things minor in comparison…. But alas it is premature. But if I can get it rolling in the near future, things can change and will turn around and change VERY fast.

As I'm doing this, I'm thinking that I may just flog this actual thread here far and wide and heavy in multiple streams and see what comes of it. With today's global communications and media of many different types and orientations. I'd canvas them ALL. Nothing ventured….. I've got nowhere to go but up and our world NEEDS these things. NOW! I'm getting closer to the end of this life cycle, so now IS the time for these things. Considering the current global situations, it seems inconceivable that if marketed in the right way that I would have to work very hard at it for it not to succeed. So it's back to the 'Gold mining' for me now, but hopefully not for very much longer! (< 8)

'Whatever You Can Do, or Dream You Can, BEGIN IT!

For Boldness has Magic Power and Genius In It!'

Johann Wolfgang von Goethe

Hi Doug,

Any time you get to the adverse condition/ham-handed operator/destructive testing phase; HAVE HAMMER&PASSPORT, WILL TRAVEL

Packrat

No worries John,

It's pretty lengthy and involved and has gotten off topic in places and I tend to be quite verbose. It's not like I am going to withhold your paycheck for not keeping up on your volunteered assistance, which I DO appreciate.

I tend to agree with you that the one rev clock mechanism will likely be to slow. If it was made to go fast enough to do the job the inertia would start to cause more headaches than it solves. I won't need any active solution to lift up a pall, there really will be no sideways force vectors of any significance if the shifter mechanism is designed and fabricated properly. Also you have to remember that it will be in almost constant rapid motion including reversing the direction of travel constantly. Regardless of what else I do I'm pretty well decided on using a passive slightly grooved strip and 4 spring loaded detents in a square or rectangular layout, with the 2 sets of 2 being offset a little bit so they don't all utilize the same location in the groove which will cut the wear rate on the 'rack strip' in half. But getting one aspect of something out of proportion can create so many other problems that then have to be coped with and it just snow balls. If you haven't encountered it yet, the 'rack teeth' are likely only going to be ~ quite a light, thin (¼" ~ 3/8") with the grooves ~1/8" deep at the most.

I'm not an engineer, though I did have some training in it, but I have decades of working with, designing 'solutions' and creating them from scratch, fixing up other's SNAFUs, repairing and fixing all sorts of and a very wide variety of devices on significantly different physical dimensional scales and sizes. Fixing and improving manufacturing design defects, done a lot of varied repair work including mechanic, LOTS of varied machining, fabricating and welding etc and some millwrighting. So I do have a good feel and sense for keeping things balanced, though I do tend to over Engineer and overbuild things. I'm from the 'old school': I build things to last: take a licken and keep on ticking, not for an engineered and built in limited, 'disposable life cycle'. Our world cannot afford such needless waste of resources of all sorts of different types on numerous different levels anymore.

Though I know the basic concepts, I don't have much first hand experience with servo motors, stepper motors, active encoders, positional sensor and feedback correction systems; but frankly the detents will do the job just fine for the demonstration prototype and likely for the production model as well. So the linear motive force and mechanism is not going to have to be REALLY precise, just get it into the ball park and have just enough free movement to allow it to be properly mechanically located and seated but not so much that it misses it. If I get it to tight I'll just bring PackRat in to 'tune it up a little'. LoL . Don't force it eh PR, just get a bigger hammer! (< 8)

I'd prefer to stay away from gears entirely regardless of the final design including for the linear actuators as likewise the finicky tolerance issues including too tight and (inevitably) to loose that are always present with gears. If I can find a low cost linear actuator with a stepper motor or encoder combo I'm open to it. If not and I can get enough 'traction action' form ir, it will be the light spring 'steel belt' of some sort and a couple of pulleys, with the idler being under spring tension to keep it taught and accurate. If I utilize a cable affixed to the driving pulley that is 'grooved' with a 'threaded circumference' for the cable to accurately to always seat into controlled positions. If I can get enough 'traction action' the thin (light spring) steel band that the generic Guru 'NickName' suggested is also an excellent option. I'm not opposed to a prefabricated linear actuator, I just don't have enough firsthand experience to say: 'Yep I know exactly the type and one that will do it' Before I do get down to drawing up the actual design I'll get it nailed down precisely so that if I have to make some slight adjustments and compensate for a slightly different incremental movements to accommodate the stepper motor or whatever I end up using then I can and will do that. If I don't find a suitable, reasonably priced off the shelf solution, I haven't decided on the exact type of setup for the linear moving part to run in. I'm thinking that if I'm smart and careful enough I may get away with really low balling it with some cold rolled steel tubing, channel or angle iron that will require little if any machining at all. Time will tell. The suggestion of scavenging the complete mechanism off of a wide heavy duty used commercial (blueprint) printer is very attractive for a lot of obvious reasons.

None of this is going to start manifesting until money issues get handled one way or another and I'm open to collaborations, corporate or more likely at this stage, sweat equity partnerships or ??? If I get a 'business type' involved, which I need, on a sweat equity basis to put together a good business plan and perhaps find some minimal outside financing to get things in motion and rolling. Frankly at this stage, I'm not willing to give up as much as I would have to in order to bring an 'angle/venture capital' partner in and give most of it up to them. I should be able to generate some substantial and significant enough capital to get it underway and have something concrete that can then be leveraged with government grants etc. Magna International, the Canadian based major auto parts manufacturer is cooking up a deal with the federal government to pick up some dying auto manufacturing plants and equipment cheap and bring a whole new concept on stream for designing and building personal and light commercial and industrial vehicles. I SOOOOooooo much want to draft up some substantial correspondence and say to them: Hey, look at this CVT and engine I've got. I haven't brought this up before, but I'm fairly certain that I also have a significant development that will make mass produced electric vehicles a reality as well as they will only need a couple of hundred pounds of batteries which is equivalent to an engine. This cuts down the battery pack by a few hundred to a 1,000 pounds of dead weight which further reduces battery requirements which translates into a lot better performance and efficiency, longer range and less power requirements, resources and pollution regardless of what the initial power source is. This technology is applicable to many other things as well. The greatly reduced battery requirements cuts down the huge volume that they currently leaves no room for anything else in a vehicle and thus it would not be hard to adapt current major body styles to utilize these. They open up a lot of options that aren't otherwise possible, including a realistic mass produced flying (urban) transportation vehicle which would cut the urban transportation infrastructure costs VERY substantially. And after that, there may be things that will make all of these things minor in comparison…. But alas it is premature. But if I can get it rolling in the near future, things can change and will turn around and change VERY fast.

As I'm doing this, I'm thinking that I may just flog this actual thread here far and wide and heavy in multiple streams and see what comes of it. With today's global communications and media of many different types and orientations. I'd canvas them ALL. Nothing ventured….. I've got nowhere to go but up and our world NEEDS these things. NOW! I'm getting closer to the end of this life cycle, so now IS the time for these things. Considering the current global situations, it seems inconceivable that if exposed and marketed in the right way that I would have to work very hard at it for it not to succeed. So it's back to the 'Gold mining' for me now, but hopefully not for very much longer! (< 8)

'Whatever You Can Do, or Dream You Can, BEGIN IT!

For Boldness has Magic Power and Genius In It!'

Johann Wolfgang von Goethe

Oh no... you've finally lost it completely.

I, too, am that age where I think I repeat things. But rarely do I repeat things in exaclty the same word order and length, hundreds of word at a time. This may be a very advanced form of echolalia.

Hoping you can get a grip,

Blink

You should have a look at Chris288's latest extravaganza

http://cr4.globalspec.com/thread/49156#newcomments

Should be fun & Chris has autocad skills for days

Hi,

I have not forgotten about your last posting and appreciate you making it. I've been side tracked with higher priority tasks, but I will try and respond to it soon.

http://www.amacoil.com/rolling-ring-animation.html

Hi Chris,

Thanks for the info. It appears that the functionality of it would fulfill my needs, but from the video it has a number of features that would seemingly rule it out. However I will check into it further thanks

{p]Quite the ambitious and wide ranging forum you have going. It looks like you are generating a lot of interesting and informative communication on it. As the Aziys say: 'Gud on ya mate!'

I first heard about Uhing Amacoil back in the early '90s, and ordered a vhs video from a magazine (I think it was Machine Design). I was completely blown away. I was investigating Lead Screws for machining applications at the time. I do believe that they have an engineering department, and will work with entrepreneurs to develop custom applications... Wouldn't hurt to give em a call.

As for my thread on modular vehicles, I just hope it grows into something useful. I believe that there can be a system(s) that can work,and I hope that we can define the parameters of workable systems. Then people who have the wherewithal to create real products and vehicles can find a well thought out open-source resource.

Thanks. I'm still thinking and building my responses to you.

Chris

Because of numerous factors, small scale vehivle production and companies are returning with good prospects with the right formulas and mix.

(8 >) I thought I'd get a 'short one' off to you when I spoted teh opportunity (< 8)

I will continue on the morrow

Doug,

Go to Globalspec and do a search for linear actuators. I can't find it right now, but there are a couple of producers of these things who use stepper motors as prime-movers. Relatively simple chip to controll these.

You might have to call on the assistance of an electronics guy to set it up for you though.

Just the thing you need, tight op tolerances, low mass, low voltage. Could have perhaps a mechanical overide as a redundancy.

The units I'm thinking of would be outside the influence of the 'geartrain' lubricant, although they have a high temp tolerance.

Cheers, Stu.