Need Help Mechanical double lid lifter

[Danger]

With no offense intended toward anyone, I think that it's time to put this thing to sleep.
All logical, technologically plausible, approaches have been offered, and OP doesn't accept them. It seems clear to me that he wants something unattainable. Let's just pull the plug. (Unless, of course, someone with BlackOps training, Umbra-Level security clearance with a Q rating, and an alcohol problem cares to offer the ultimate solution... )

 

[cybertron]

Are Those your own words. Or dose he speak for every one else.

And no offense intended.

I do have a very limited experience in Mechanical design>

So My intensions was to come to a forum such as this one to get the Help I would need for my project. Seems to me I been getting that.

I have not refused any such offers or suggestions from anyone on this forum. All help is greatly appericated.But How could I use a suggested idea from anyone if the idea dose not fit my objective or work for me in my project.

If you feel as you speak.
Then I'm greatful for your EXPERTISE that you have contributed to my thread.

 

[cybertron]

nvn

Nice video! I see how this mechanism that you provide in post #14 works and functions do to this video.

I see as the left short tube position opens ''point A'' rotates as it pulls torwards ''point C'' as the right side pushes up on the opposite side to lift the shorter tube on the right side as the process reverse to pull torwards ''point A'' went it closes.

At frist in your #14 post I didn't noticed that linkage rod A is longer then linkage C and how A and C positions are mounted high and low above and below the hinges knuckle to give the leverage to lift each side.

How would you attach a motor to this mechecnism or would you have to modified or change the complete design for this mechanism design to function.

Is there a way to show me this in a video. That if you could.

P>S How did you make that video to have that move like it dose If you can explain.

Thanks.

 

[cybertron]

tyroman

I understand what you are stating in post 58

I could lift up the tube to 3/4'' as stated with another piece and maybe to 1'' BUt 1'' that the maximum do to the low point where the door sits low form the top of the longer 1'' tube.The door thickness is only 3/4'' and 1/2 of that sits inside the entrance hole I will have to add a vertical piece to the top of the shorter tube and bend it to account for the diffrence in height but that's not a problem if I don't go higher then 1'' under the long tube.

So your saying the rack and pinion Can't be higher then the closed shorter tubes if that's the case then the plate mentioned in the last few post dose have to be higher the shorter tubes either. correct!

The counterweight reducer will be a spring in reducing the weight of the doors if that's the case the motor will easily lift the door even through it could lift 40lbs.


As to the 41lbs of force if that's the total force of both doors as you mentioned then a 20lb spring would be use to low the force on the mass which is the door. Correct!

Yes 1'' from the hinge and lifting the 10lb 1'' high will have the greatest force on the mechanism to lift the lid in motion,this is where the spring comes into play by lowering the force on the center point of the door and hinge and its mass so the torque on the motor is lowed. Correct!

As for your sketch this is what i understood. If I'm wrong please explain.

 

[nvn]

cybertron: The mechanism I designed is independent of an optional motor. A motor could assist, but is not required for the post 14 mechanism to work. You could attach a motor anywhere you like, as you see fit, if you wish. I will try to leave that up to you.

 

[cybertron]

nvn

Yes the mechanism designed in post 14 dose require a motor to work; I see that.
I do want to add a motor to that mechanism and it would be attached to point (A)
on the short tube would there be a way to attach a gearmotor from the woodenbase in the space that i have to point (A) so it functions like in post 14, but with a motor.
any further help would be appreicated.

 

[cybertron]

tyroman

I added 1-1/2'' spacer under the longer tube to accommodate for the function and strenght of the rack and pinion. Thats the maximum height allowed. Do to adding that spacer to 1-1/2'' I will have to add a vertical bend piece of tubing to the shorter tube to the door because the door will sit at the lowest point of the 3'' height of the tubing.That not a major problem to change.

 

[nvn]

Would something like this work? Not to scale.

 

[cybertron]

nvn


Thanks for the added motor. I appreciated it.

Can you tell me what is the part outlined in red is, is it a standard complete part i could buy,or 3 separate parts and how is this connected to the tube. I'am assuming that the rods are rounded or flat in your image.


Ha is there a way to make a video out of this image.

that last video was nice. I keep watching it. how was it made.

 

[nvn]

I now revised the attached file in post 68; see the revised file. The linkage bars in the post 68 diagram are flat bars, not round rods. The purple sleeve (cup) is a separate part. It is a solid square bar, then you tap a blind hole along its centerline. The bottom of the cup has a rectangular hole, through which you insert linkage bar HB. Linkage bar HB must be free to slide to the left. I.e., linkage bar HB is not rigidly connected to the purple sleeve at H. I don't know if "linear motion" equipment manufacturers, etc., might have something like the purple sleeve you could buy. You will need to research all available parts and manufacturers on-line. If not available, then you can hire someone to machine some parts. No problem.

 

[tyroman]

nvn,

That is a great animation! How did you make it? Can you give me the name of the software or a link?

If he can live with your design, it would be MUCH better than the rack and pinion system I devised. It is much simpler and could be easily motorized by making the B-C link a rack and connecting his gear motor through a right angle drive to a pinion meshed with the rack.

cybertron,

I'm confused... My understanding of the Structure Limits which you had shown in your sketch at post #53 are shown in PINK on the sketch attached below. Please edit this sketch to correct any errors I have made. Also, please confirm that the doors weigh 10 pounds each, for a total of 20 pounds.

Your latest sketch appears to allow the mechanism to be up to 3" high, is this true?

Now, for the question of how much force the motor and mechanism will need to deliver:

Look again at the sketch I attached to post #59. The force necessary to start opening one of the doors with the mechanism is represented by the arrow labled "total force on linkage". You will see that it is much longer than the line representing ~41 pounds. I have not calculated that force (it will depend on the final configuration of the mechanism and the size of the angle "theta" shown on the sketch), but I would expect it to be in the range of 100 pounds.

Since the motor will be moving BOTH doors at the same time, it will need to deliver twice the force; or about 200 pounds. Any spring or counterbalance system should be set up to make the effective weight of the doors as small as possible.

 

[cybertron]

tyroman.

I will try and made both mechanisms to see which would work best for my project.

I don't know what you mean or indicating about post 53.

The doors do weight 10lbs each for a total of 20lbs. I did not install them they were already inplace.

How do i know each door weights 10lbs, I weighted both doors with a scale' and off there hinges and on there hinges.

These doors are made with 2peices of solid wood 1/2'' thick for both doors this wood is not the kind of wood you can buy at any home improvement store this wood is solid plank boards that they would of used 60+years ago before they had plywood as we do today.There in great condition i just planed each side down 1/16 of inch to get the original grain of the wood back so I could stain them.

tyroman:you did mention in post i think 55 or 56 if I can increase the height of the tubing this will increase the strenght and function of the rack and pinion system.So this is what i did to compensate for that in my last post.

Yes. its ture, I did increase the height of the tube with a 1-1/2'' spacer under the tube, so i looked closer at the doors how they sit and it wouldn't be a problem to do this, but I CANNOT go any higher then 1-1/2'' on the spacer.I will have to accommodate for that height with a vertical bend piece of tubing to attach to the doors since the doors will sit 3'' below the top of the shorter tubes but this is not a big fix or problem to change.

The Gearmotor I'm getting has a high torque ratio do to its very low RPMs AND GEARBOX it can lift 40lbs - 60lbs as i been told, even if I didn't use any springs this motor could lift both doors i would think. But that's not good on the motor.And you want to use half what the motor can lift so 30lbs would be right.
So by using one or two springs on each door will bring the mass of each door weight down to about 0.5lbs or 0lbs I'm thinging two 20lb holding springs would work.if not one larger spring.

tyroman:
How do you get 100lbs to 200lbs on the rack and pinion mechanism the motor is applying the force and the springs that's lifting the doors the rack and pinion is there to guide the door in the lifting. Mostly all the force I would think is placed on the motor when lifting the two door up. Please explain I'm trying to understand this.

NVN.

As I and tyroman stated what program did you use for that video was it Windows Movie Maker or some other program can you please name the software or a link to that program as tyroman suggested.

 

[cybertron]

I now revised the attached file in post 68; see the revised file. The linkage bars in the post 68 diagram are flat bars, not round rods. The purple sleeve (cup) is a separate part. It is a solid square bar, then you tap a blind hole along its centerline. The bottom of the cup has a rectangular hole, through which you insert linkage bar HB. Linkage bar HB must be free to slide to the left. I.e., linkage bar HB is not rigidly connected to the purple sleeve at H. I don't know if "linear motion" equipment manufacturers, etc., might have something like the purple sleeve you could buy. You will need to research all available parts and manufacturers on-line. If not available, then you can hire someone to machine some parts. No problem.

nvn. As for getting any kind of part customed machined would not be an option do to a small amount i want to construct this for. Is there any standard part you can implement in the mechanism design that would be easier to find. off the self of any hardware home improvement store. at the bottom of the revised drawing don't understand the part please explain. thank you.

 

[nvn]

On linux, you can use octave, gnuplot, and ffmpeg. I don't know the details of how it works, since I didn't set it up; and I wouldn't have time to go into that. I don't know if it works on Windows or Macintosh.

cybertron, you will be the one who needs to do most of the on-line research to locate off-the-shelf parts, unless someone else here happens to find some parts for you. Also, I think there are individual machinists who will do small jobs. So don't give up before you have tried to contact them.

 

[cybertron]

On linux, you can use octave, gnuplot, and ffmpeg. I don't know the details of how it works, since I didn't set it up; and I wouldn't have time to go into that. I don't know if it works on Windows or Macintosh.

cybertron, you will be the one who needs to do most of the on-line research to locate off-the-shelf parts, unless someone else here happens to find some parts for you. Also, I think there are individual machinists who will do small jobs. So don't give up before you have tried to contact them.

I throught you might of had some other standard part for that part that will be connected to the flate stock that i could get at an hardware store. And yes i will be doing the on-line rearching which I have been doing. But the part that connects to the bar is i think a custom made part that will properly be hard to locate.Yes i will contact some machinists in my area but I do know a one item custom part can get expensive to forge.

No I'm not going to give up?

As for the flate bar what do you think i would need in size and thickness because you didn't state this.
I did find some on-line Alumimum or steel, sizes 1'',1/2,3/4'' 5/8'' wide and for the thickness 0.05'' 3/16'' or 1/8''.what would be the way to go. As for connecting the bar together, I do have some ideas.

In post 68 in the drawing what is that part in the low bottom right.please explain.

What is a program I can use for Windows like the one in the video, I don't use Mac which i think those programs work in.

 

[cybertron]

Another alternative if your current project is over budget, is an inverse trans-axle. The motor is placed at the bottom center, attached to it is a parallel gear (at 0dg.) A second gear placed perpendicular to the right of the first gear. The main gear turns counter clockwise. The second gear turns a screw, where a third one (gear and screw) is placed parallel (facing the opposite direction). Both screws turn the same direction perpendicular to the motor or drive shaft, to form the main axle. Attached to each axle is a cable that pulls each door open or closed, both at the same rate and in equal and opposite directions. To be more specific the two main axels are attached, such that the counter clockwise drive rotates both axles clockwise, pulling the doors open.

This might not work do to the space that the motor must be place in.
Can you show a 3d drawing of this alternative option.

All suggestions, ideas, and help is greatly appreciated. thank you.

 

[nvn]

As for the flat bar, what do you think I would need in size and thickness? ... In your post 68 drawing, what is that part in the lower, right-hand corner? I don't understand the part. Please explain.

cybertron: Don't worry about sizes just yet. You are not ready to select stock sizes. The view shown in the lower, right-hand corner of my post 68 diagram is a bottom view of the linkage bars shown above it in the side view. This gives you two views (side view and bottom view) of the connection at point B. All of my parts (in the post 68 and post 14 diagrams) are inside the square tubes, except for a portion of linkage bar AB, which passes through slots in the long and short square tubes, as stated in post 39. The motor in post 68 is also outside. Unlabeled views on a drawing are called orthographic views[/color] (orthographic projections).

 

[tyroman]

cybertron,

In your post #72 you say;

"I don't know what you mean or indicating about post 53."

Here is what I mean...
In your post #53 you attached a sketch titled;
"End on view area to work.png 1.PNG"
On that sketch you have the following notes;
"This area is what I have to work with."
Next to that note is a long line with arrows at each end. It is labled;
"18" long space is length of the 18" tube".
Another shorter line with arrows at each end is labled;
" 2" space"

Also look at your post #56 where you say;
"Yes the mechanism and motor that I use must fit in the 2''x18'' limited space."

Now look at the "Plan view B.PNG" sketch I attached to my post #71. The only space on that sketch which is not PINK is the 2"x18" space between the mechanism and the wall. What I need you to do is either confirm or correct my understanding that no part of the mechanism or motor can be in the PINK space shown on "Plan view B.PNG" attached to my post #71.

 

[nvn]

The image I posted in post 60 was grossly simplified, because it has the pins (points A and D) collinear with the hinge and square tube face. In reality, these two pins are offset from the square tube face. Now that I am taking a quick look at the actual configuration, with accurate dimensions and accurate pin offsets, I am currently unable to get both doors to open to the same angle at the same time using the post 14 design. If there is a solution that makes both doors open at the same rate and to the same angle, I have not been able to find it, in a matter of minutes, using the asymmetric post 14 concept.

I am starting to think we may be required to use a symmetric design.

 

[cybertron]

cybertron,

In your post #72 you say;

"I don't know what you mean or indicating about post 53."

Here is what I mean...
In your post #53 you attached a sketch titled;
"End on view area to work.png 1.PNG"
On that sketch you have the following notes;
"This area is what I have to work with."
Next to that note is a long line with arrows at each end. It is labled;
"18" long space is length of the 18" tube".
Another shorter line with arrows at each end is labled;
" 2" space"

Also look at your post #56 where you say;
"Yes the mechanism and motor that I use must fit in the 2''x18'' limited space."

Now look at the "Plan view B.PNG" sketch I attached to my post #71. The only space on that sketch which is not PINK is the 2"x18" space between the mechanism and the wall. What I need you to do is either confirm or correct my understanding that no part of the mechanism or motor can be in the PINK space shown on "Plan view B.PNG" attached to my post #71.

The 2''x18'' is the area that's left where I must place the motor and where the rack & pinion mechanism will be placed and attach to the long tube.My tubular lifter is in the that space already.
My post in 53 is showing you indicated by the arrows that the 2''x18'' is the space where the motor and the rack & pinion mechanism will be placed in. The lifter is in that space too but what's left is an area of 2''x18''

Right! There should be NO pink area from the tubular lifter to the wall this is where the motor,rack&pinion mechanism and the lifter. In post 71 you have the lifter tube hindden in the pink area. which it shouldn't be.

If you can Picture two leaf style cellar doors that open from hortizonal to vertical there should be nothing blocking that area to enter.

 

[cybertron]

tyroman

I edit post 71 to show you what the top view would look like if you were looking down at the two door.

As you can see you have the tubular lifter than the mechanism then the left-over space which would now be 1-1/4'' from the mechanism to the wall.

As stated in post 53 and 80.

The pink area ENDS where the tube lifter begins.As indicated in edit image.

 

[tyroman]

nvn,

I think it is less important to cybertron that the doors move "exactly" in unison than it is that the motion of the mechanism begins with both doors at 0 degrees and ends with them in a 90 to 100 degree position... can you find a way to position the A and D connections and adjust the length of links A-B, B-C and C-D to make this work? Perhaps have the A and/or D connection(s) made at a "crank" attached to the short tubes (see attached "nvn's links.PNG" sketch).

Also, since cybertron's earlier clarification that the mechanism does not have to be "inside" the long tube and that the long tube will be installed "with a 1-1/2'' spacer under the tube", there is more vertical room to position your mechanism if you attach it to the side of the long tube rather than inside.

Mounting the motor as you have described (off the end of the long tube) may be unacceptable to cybertron (based on the 2"x18" work space)... but I think this can be solved with your design if the motor is connected to a right-angle drive
see:
http://www.torquetrans.com/right-angle-gear-boxes/miniature-right-angle-drive.htm
http://www.torquetrans.com/right-angle-gear-boxes/images/ra202_figure_1.jpg
or bevel gear:
http://www.qtcgears.com/KHK/newgears/KHK230.html

which is then connected to a pinion mounted on the side of the long tube. The pinion would mesh with teeth on the edge of your link B-C (which would be made from a rack of appropriate length). See sketch "door-mechanism-05 (with motor).png" attached. This would also be the way to motorize the double rack and pinion design if that is the way cybertron decides to go.

Again, I believe your design will be stronger and simpler than the double rack and pinion design... if we can make yours work.

 

[nvn]

tyroman: I tried about ten different ways, so far, and could not get both doors to end in the range 90 to 100 deg. But I will continue trying all of your new suggestions (or any others you may think of) over the next several days, to see if I finally get lucky and find a combination that works. I'll let you know as soon as (if) I find something that works.

 

[cybertron]

tyroman

I just want to know if the two doors don't open in unison how would both doors open exactly at 90 and 100dgs. And close at the same time at 0dgs.

If one door starts to open,then the other door follows 20dgs behind how would both doors
reach 90 0r 100dgs exactly. I would think one would be at 90 the other door would stop at 70dgs or less. That would be unacceptable.

Now if both doors start opening from 0dgs in unison both doors will stop exactly at 90 0r 100dgs went motor stops at that angle.This is how they must open. If they don't one door could block the entrance at a predetermine angle and that's not good.

They must open in unison to close in unison so either door does not block the entrance do to the small foot print of the opening.

 

[cybertron]

tyroman


In post you also showed nvn in the first image how the door are attached to the short tubes,They are not attached there.

The two doors sit at the 1-1/2'' spacer level sits. I did not indicate at all that the doors would sit on top of the shorter tubes nothing can go on top of the shorther tubes,But There will be a bend piece of metal that will be attached to the top of the shorter tubes bend at a 90dg angle then 3'' down then bend at another 90dg angle then attached to both doors. I stated this in my post in 67. The two doors sit at the wooden base level,not on top of the shorter tubes.I showed you in post 82 how the tube would look from a top view. Because the two doors sit at the woodenbase level or floor level. I did state in post 67 that a piece of bend metal will accommodate for the 3'' heigth difference do to where the two doors sit. They do not sit on top of the shorter tubes.

 

[nvn]

I have not been able to get both doors to end anywhere near the range 90 to 100 deg using the asymmetric post 14 concept. Therefore, as mentioned in post 80, I am starting to think you may be required to use a symmetric design.

 

[cybertron]

I have not been able to get both doors to end anywhere near the range 90 to 100 deg using the asymmetric post 14 concept. Therefore, as mentioned in post 80, I am starting to think you may be required to use a symmetric design.

Ok, So the concept for that propose mechanism in post 14 will not work at all, what was the reasons for not getting the doors to 90dgs,was it the limited space or other factors of the design. And using an optional motor.



As for a symmetic design will this concept work, and will it work in such a small area with the optional motor as mentioned.

 

[nvn]

The main reason the post 14 concept does not work is due to the asymmetric mechanism geometry.

I have not worked on a symmetric design much, myself (except for posts 7 and 10).

 

[cybertron]

Tyroman

Is your mechanism design concept a asymmetric as nvn concept in post 14 or is your concept symmetric as nvn proposes that a symmetric design will be needed.

Will your concept as proposed work also.

 

[cybertron]

What about something like this? Not to scale.

nvn

In this design concept as proposed in post 10 is there a way for this to work in the small limited space that i have and using my motor that's been mentioned in this thread with the concepts that already been stated and suggested by you as well as tyroman suggested with right angle gears and rack parts.Is there any other combinations that you could come up with in this concept that can work in my project do to the limited space and geometryand getting the doors to open and close at 0-90dgs.
In post 67 i increased the height with a 1-1/2'' spacer to compensate for the rack and pinion that tyroman advised,So I have now about 3'' from the wooden base to the top of the shorter tube to give some more height to the area.

I hope you have not given up on me just yet! But i do Apperciate all the time you have given to me on the mechanism design and to this thread.