Need Help Mechanical double lid lifter

[tyroman]

The pink (a volume not a structure) indicates areas where the opening device structure can not be located... the space indicated on the attached sketch would show that the mechanical device is not allowed to extend into the space below the long 1" square tube (for example).

If we know the constraints on the mechanism (such as "no-go" areas) we can avoid guessing at what will work for you.

As to what a "bell crank" is, see the second attachment.

 

[cybertron]

The pink (a volume not a structure) indicates areas where the opening device structure can not be located... the space indicated on the attached sketch would show that the mechanical device is not allowed to extend into the space below the long 1" square tube (for example).

If we know the constraints on the mechanism (such as "no-go" areas) we can avoid guessing at what will work for you.

As to what a "bell crank" is, see the second attachment.

What do mean by ''no-go'' areas. Please indicate this in the 3d image so I could see what you are implying to, then i could reply back' to these constraints on the mechanism.

 

[cybertron]

nvn

In #14 must the linkages be connected with a tight fit, loose fit or dose it matter how tight these linkages must fit together.

Also I forgot to ask you.
When I close both of the small square bars on the Lifter to the closed position, will they be pulling against each other preventing the two small bars form closing to the 0-dg position. I can't have this happen, ''then the two lids that will be connected to the Lifter can't close.

The lifters function must beable to open and close with one bar assisting the other bar when opening and closing the two lids.
When one side of the small bar is pull up from the close position the opposite side starts lifting at the same time assisting the opposite side and rotates to any angle between zero degrees to 100 degrees. as the small bar gos back down and returns from 100dgs to 0dgs one bar will assist the other small bar down to the 0dgs close position.

 

[tyroman]

cybertron,

I'm just trying to figure out what your physical constraints are... in some of your posts, I get the idea that there are locations around the square tube assembly that are "off-limits" or "no-go" for the opening mechanism. For instance, if the bottom of the 1" square tube will be mounted on a concrete slab, then no part of the opening mechanism can extend below the 1" square tube. If that is the case, then the pink area in my sketch (below the 1" square tube) makes that constraint clear.

from your post #5:
"The rod you included will not work in that position. And the bottom part can't be used.
But it is close."

from your post #8:
"Close. Still bottom part will not work and that top piece can't be there"
and
"Much closer the bottom still wouldn't work in my application"

from your post #12:
"the mechanism will go through the sq tubing"

Your statement above in post #12 seems to say that the mechanism must be inside of the 1" square tube... is this true?

*****

Did my sketch of the bell crank help? Can you see a way for such a device to be used here?

 

[Danger]

Agreed; this is becoming quite frustrating. Cybertron, can you please tell us just exactly what the hell this thing is for? Knowing the end application makes it a lot easier to come up with a workable design. So far, it could be anything from a bar fridge to a missile silo.

 

[nvn]

cybertron: Regarding your post 33 questions, the linkages should be connected with a relatively tight fit, but must be free to rotate about the clevis pin centerline axis with little friction.

The lifters must be able to simultaneously rotate to the same angle, from 0 to 100 deg.

Both doors will close to 0 deg at the same time. In my post 14 very rough sketch (not to scale), it is intended, or hoped, that both doors will open to approximately the same angle simultaneously. You would need to create a design (on paper or CAD), designing and selecting the best possible locations for points A, B, C, and D, then draw the design exactly to scale to see how (if) it works for the chosen coordinate locations of points A through D.

 

[cybertron]

Agreed; this is becoming quite frustrating. Cybertron, can you please tell us just exactly what the hell this thing is for? Knowing the end application makes it a lot easier to come up with a workable design. So far, it could be anything from a bar fridge to a missile silo.

No its not a bar fridge. And I assure you It not a missile silo. Now THAT's Funny!

Its just a lifter for lifting two lids. This is only one part of three parts of the puzzle, But I already have two parts of the my system solved. the lifter is the second part that i already have designed from my simple sketch that i posted in the beinging of this thread and tyroman and nvn took my simple sketch and done a 3d image.The last part of the puzzle is the (Mechanical Mechanism) to be attach to the lifter, this is why I came to this forum for that help.

I see your point and frustration, But you're reading more into this (my help) then what is needed. Look at my simple sketch then look at tyromans its the same thing 'tyroman just make a 3d image of my simple lid lifter. I need a Mechanical Mechnism to be attach to the lifter to lift up the two smaller hinged tubular square bars to assist one another at the same time. As stated.

 

[cybertron]

Tyroman

I understand that you're try to figure the best why to help, and i appreicate everyones help.

Now i understand what you mean by "no go" being off limits and that pink area in your sketch becomes clear to where the mechanical mechanism can go on the lifter.And how the lifter will be mounted.

1.Your right . The lifter will be mount on a wooden board on top of a slab and no part of the opening Mechanical Mechanism can extend below the 1'' long square bottom tube.As made clear by the pink area in the 3d image.

from my post #5:
What I ment is the tubular frame of my lifter in that image is close, and YES the rod wiil not work or the bottom part, do to the constraint limits beyond the long square tube.


from my post #8
what I ment also the tubular frame; Right the rest of the system will not work do to the constraints below the pink area that's indicated in your 3d image.


from my post #12
YES. This statement that i stated is only (true) if a mechanism can be make to go through the tubing if it can be made and operate to lift the two small tubes to assist in lifting both sides. If there's no way that this can be done or operate, Then NO. Then is must be attach to the tubing as in NVN post #14. Tyroman do you think it could be made to BE put through the bottom of the 1'' square tubing to work in some way as in post #14.


As for the sketch you provided on the bell crank I really don't understand from your image what it is and how this think is surppose to work or if it can work in my application. Just don't know.

 

[nvn]

cybertron: The mechanism in my post 14 diagram is inside the square tubes. You stated this requirement in the first sentence of the third paragraph of post 12; and therefore, I posted my diagram in post 14. The only thing not inside the tubes is a portion of linkage bar AB. See the last sentence of post 16.

 

[tyroman]

cybertron,

Here is another try at the bell crank sketch...

Can You think of a way this mechanism would work?

 

[cybertron]

cybertron: The mechanism in my post 14 diagram is inside the square tubes. You stated this requirement in the first sentence of the third paragraph of post 12; and therefore, I posted my diagram in post 14. The only thing not inside the tubes is a portion of linkage bar AB. See the last sentence of post 16.

Nvn. Yes I did stated this requirement,that I want the Mechanial Mechanim inside the long 1'' square bottom tube then it gets attach to the smaller tubular tubes, I didn't realize this could be done or anyone on this forum understood what i was speaking about when I state this in my frist sketch that I posted.

I assumed that this diagram in post #14 that the mechnism is attach on the sq tubes not on the inside.
If you originally drawn diagram in post #14 for the mechanism to work on the inside then this changes the way the rods or bar of the mechanism is made to work and attaches too the two smaller 1'' square tubular bars do to the angle of rotation of how the smaller tubes will open and closes from Odgs-100dgs. I will try too show this in a re-edited of tyroman 3d image.


I'm thinking your diagram in post 14, that this Mechanism is attached on the outside of the long tube and the smaller tubes.I 'm getting confussed on how this Mechanism is being attached to the to these square tubes aqnd the rotation of angle if this mechanism is going to be attached on the inside of the longer tube and the smaller sq tubes.

 

[cybertron]

cybertron,

Here is another try at the bell crank sketch...

Can You think of a way this mechanism would work?

I don't think this will work. And I still don't understand how it functions,maybe this is way I can see this working. Are the long vertical lines the rods connected to the smaller tubes, is the bell crank a handle that you crank 360dgs to move it,how is this connected to the lifter.Is there a real picture of this device that you can show me.I just can't get how this functions.

 

[cybertron]

Nvn.

Enclosed is an edited 3d image.


The mechanism that will lift the two smaller sq tubes the rod linkages would have to change as i stated in my last post to you,unless I cut a slot as you stated in the top part of the longer bottom sq tube so the rod rotates to a fully 0dgs -100dgs.
This might be difficult to do without a grinder.

If you can make a more detailed diagram from the image i posted on how this will work if I don't use a grinder for slots in the bottom top part of the tube for the mechanism to rotate.

Can you make a more detailed diagram you can copie the image post then edit it.

 

[nvn]

Enclosed is an edited 3d image.

cybertron: I currently don't think this will work.

I'm getting confused on how the mechanism [in your post 14 diagram] is ... going to be attached on the inside of the long and short square tubes.

Keep rereading my posts (posts 16, 25, 30, and 36) to help you understand how the mechanism in my post 14 diagram works, and how it would be designed. This is the mechanism I currently recommended. I think you may come to understand it better if you keep studying and imagining the descriptions I have posted.

You will need basic tools to manufacture anything. If you do not have basic tools, then you will need to hire someone to cut the metal. No problem. But don't worry too much about this until you have first designed a workable mechanism, as I described in post 36. And see also posts 16, 25, and 30.

 

[tyroman]

cybertron,

Since it appears that the mechanism can be positioned on the outside of the lower bar, I have made the attached sketch to show a worm drive mechanism that might work. Also attached is a sketch based upon nvn's mechanism but using a rack and pinion scheme.

Let me know if you have any questions.

 

[cybertron]

tyroman

The frist image of the mechanism you drawn connected to my tubular lifter in the 3d image
with the Hank crank and wrom gear is not really what I'm looking for.

Now The second image with the tandem rack & pinion that you drawn base on nvn mechanism attached to my tubular lifter, could be used.Its a mechanical mechanism and can be build with simple hand tools.

Also when the two smaller sq tubes are in the closed position will it lift without hardly any force if I lift one side by hand.There can't be any binding in the rack and gear system.


But I do have Questions.

Lifting function.
As I lift either the right or left small sq tube to open by hand the opposite side will assist to lift the other side at any rotation from 0dgs to 100dgs and when it closes to the 0dg position the two sq tubes will assist each other when closing the lids.

1.Frist the longer sq tube on my lifter is no higher then 1'' will this tandem rack system extend above that 1''; if it dose then the small sq tubes will not close to the 0dg closed position.How would you make this gear and rack system within the 1''depth of the longer sq tube.

2.This gear would have to be no bigger then 1/2'' dia is that possible to buy.

3.Where would I buy a standard rack system that can be used with a metal gear, assuming the gear will be metal.And There's no way I could make this gear or these rack bars.

4 Is this gear and rack system going to operate smoothly when it moves in either direction with such a small metal gear.

5.How thick sould the gear and the teeth on the gear be to operate within the rack bars and should the racks teeth be the same thickness as the gear teeth.

6.the Pivoting linkage bars that attach to the two shorter sq tubes at the connection this connection must rotate Yes or no.
I'm thing it has to rotate to acommendate for the angle of rotation and the same gos for where the linkage bar connect to each side of the rack bars.

Tyroman:I understand 98% how this mechanism will work but the 2% i don't get it this PIVOT CAGE.
Please explain to me what is the pivot cage what it is,what it dose,how its connected to the 1'' tube

 

[cybertron]

nvn.
I will read all your post again!

As for tools:
I do have all the basic tools to construct with; even some metal tools like hacksaws.
'But I don't have a grinder, as you stated.Or any metal mechine tools if needed.
Would I need any special metal cutting or drilling tools in making this mechanism in post #14.

If I need a grinder I can get one,will I really need it.yes or no.

 

[tyroman]

cybertron,

Can you say why "the Hank crank and wrom gear is not really what I'm looking for"?

The Worm/Worm Gear design will be easiest to motorize... it will NOT however, allow you to lift the doors by simply grabbing one and pulling it open. The hand crank (or a motor) would be the ONLY way to open or close the doors. Is this the reason it is "not really what I'm looking for"?

The Tandem Rack & Pinion design will NOT be easy to motorize.

In your very first post, you say;
"How can i make one of the 9'' bars lift as the other 9'' bar is being lifted by a motor."
In post #9, you say;
"one side will have a motor to lift one of the bars"
In post #12, you say;
"I will include a motor that will only assist with the weight of one side of the lid."
You refer to a motor in several of your other posts...

What about the motor? Is a motor still a part of your design?

***

As to your questions about the Tandem Rack & Pinion design;

"1.Frist the longer sq tube on my lifter is no higher then 1'' will this tandem rack system extend above that 1''; if it dose then the small sq tubes will not close to the 0dg closed position.How would you make this gear and rack system within the 1''depth of the longer sq tube."

Look closely at my sketch (use the magnifier if necessary). You will see that the entire Rack & Pinion mechanism (including the linkage bars) is drawn in Black (the only parts in Gray are those hidden by the Pinion Cage and the Rack guides). This means that the mechanism is mounted on the front (nearest to the viewer) side of the long square tube.

? Are the short square tubes wider than one inch?

If a mechanism which is attached to the front surface extends higher than the long tube, how would it interfere with the closing of the short tubes? I suspect that there are more "off-limits" spaces than you have told us about...

Please clarify the Off-Limits issue before we proceed. Use my sketch at post #21 to do this. (There is no need to label any parts... just draw pink lines to outline ALL no-go areas.)

***

As to your questions about the articulation of the various designs offered by nvn and myself; get some cardboard, stiff wire and some thumb-tacks and build yourself a 2-dimensional scale "mock-up" of the assembly (a 1" by 18" strip of cardboard would represent the square tube at the bottom, for example). Use the stiff wire to make the "linkages" and the tacks to function as hinges and linkage attachment points. Then experiment with your mock-up to convince yourself that a particular design can (or can not) be made to work.

***

PS; The pinion cage is simply a pair of brackets (attached to the front of the long 1" square tube) which will insure that the teeth on the two racks mesh with the teeth on the pinion. The rack guides are similar in design and purpose.

 

[cybertron]

Tyroman



There's Four reasons why the hand crank/worm gear will not work for me.

1.Safety I need to open the two lids by hand if something ever stops the motor from not functioning this way I could open and close the lids by hand.
2. Optional not to use a motor if I choose that option.
3.Security Don't want the need for just anybody to use the hand crank two lift these doors at free will.
4.TimeIt will take to long to crank open a door. Then by opening by hand 2secs tops.

So I need this Mechanism to work By hand as i lift one side the oppsite side opens the other side with the assistance of the mechanism as stated in thread. But with motor assist.

Yes a motor is part of my Design as I stated. ''But only if I choose that option.And only assist with the weight of one side of the lid.


As to the off limits.
Enclosed 3d image.

The black arrows indicates the Pink Linesthat represent the outside and the inside as well as the depth of the long sq 1'' tube. nothing changes as of the long tube, BUT the rack system guides might interfer with the closing and opening of the smaller tubes. Until I construct this system and the materials i use ''will'' I know if the rack guides are going to interfer with the the opening and closing of the shorter sq tubes.The longer tube is only 1'' square that's not much room to attach the gear and rack guides.So if the guides for the rack system is higher then the long bottom tube it could interfer with opening and closing of the smaller tube.

All tubing is 1'' square.

Please answer Questions 3,5, in post #46

Would I beable to use a 1'' gear because the longer sq tube is only 1'' or would i need to
use a gear 1/2''.

I do see that this gear and rack system is on the outside of the sq tube facing towards the viewer.

Can this mechanism be make to work by hand as i wanted in this thread plus a motor as
an option.I do not want a crank device.

 

[tyroman]

cybertron,

I do not follow your logic on the reasons a worm drive will not work for you;

1. The shaft of a motor can be turned by hand when it is off. Only if the bearings in the motor have "locked-up" will this not be the case... but a locked-up motor attached to ANY mechanism will prevent operation of the mechanism.
2. A decision NOT to attach a motor will not affect the operation of the worm drive.
3. A person who is able to turn a crank would be unable to lift a door?
4. The time to open the door with the worm drive is entirely determined by the coarsness (threads per inch) of the worm and worm gear - very coarse = few turns of the crank.

OK, there will be a motor.

You say;
"Yes a motor is part of my Design as I stated. ''But only if I choose that option.And only assist with the weight of one side of the lid."

If the lids are connected by the opening mechanism, how will the motor "only assist with the weight of one side of the lid"? The force applied to either door (by hand or by a motor) will have to be sufficient to raise BOTH lids since they are connected.

As to your attached sketch;
In your off-limits sketch... are you showing that no part of the mechanism may be located within the Articulation Limits (Red Lines) of the short square tubes? If so, this goes without saying.

I have attached a sketch to show the Structural Limits as I understand them. The "End View" may help us define the space available. The sketch also shows the wooden base as a Structure (in Green), which I assume will allow some of the mechanism to extend below the long square tube if necessary. The concrete slab is shown in Pink (the extent of this slab can be ignored as long as it is all lower than the wooden base).

A second sketch below shows a simplified, End-On view of the design with a possible solution to the 1" limit on the height of the mechanism. The plate shown would be attached to the side of the long 1" tube (with spacers if necessary) and would allow more room for attachment of the mechanism. See what you think.

Your other questions have a lot to do with how heavy the doors are and other variables which have yet to be defined... Your options may be somewhat limited by hardware availability in your location. Try Google. If you have a good "mechanical sense" you may find something which can be "made to work".

For articulation questions, see my suggestions at post #48.

Your last question;
"Can this mechanism be make to work by hand as i wanted in this thread plus a motor as an option."
Yes. The pinion gear could be splined or keyed to the motor shaft (with the motor mounted on-axis with the pinion) or the motor could be equipped with a separate gear which engages teeth on one of the racks at a right angle (perpendicular). (With the worm-drive, the motor would be mounted and connected on-axis with the worm shaft at the end opposite the hand crank.)

 

[cybertron]

Tyroman

Forget the hand crank do not want it.


What I want is this mecchanism to work by lifting one side by hand as the opposite side is being assisted by the lifter as stated, but some way to use one motor on the lifter if I choose to.
As dictated in the mechanical mechannism base on nvn mechanise and your revised tandem rack and gear mechanism to be attached to my tubular lifter.

The motor will lift the weight of one side of the lids,as the side with the motor lifts the smaller sq tube the opposite side will be assisted by being attached to the opposite smaller tube. I want only one motor in the system not two, this is the purpose for the lifter to assist in lifting the opposite side.either with or without a motor. But still i want it to work both ways.The doors are only 20lbs.

Yes the motor must be rated to lift that 20lbs. If this is what you imply. It sounds to me that you'll using two motors. Are you. I want to use only one motor.


As for off -limits
Yes no part of the mechanism may be located within the Articulation limits of the short square tubes. As you indicated in pink area in the most recent 3d image.

Nothing can extend below the long sq tube. because the long sq tube will be screw down to the top of the plywood base this is clarified in edit end-on view 3d image.

There's a limit to my mechanical ability to some extend, this is why I came here for help.



Your last question;
"Can this mechanism be make to work by hand as i wanted in this thread plus a motor as an option."
Yes. The pinion gear could be splined or keyed to the motor shaft (with the motor mounted on-axis with the pinion) or the motor could be equipped with a separate gear which engages teeth on one of the racks at a right angle (perpendicular). (With the worm-drive, the motor would be mounted and connected on-axis with the worm shaft at the end opposite the hand crank.)

TYROMAN:
Please show me in a 3d image how this can be applied without using a hand crank but can be lifted by hand and with a single motor as implyed.

 

[tyroman]

cybertron,

If your wood base set-up is as you describe it (and can not be modified), then we are back to the Structure Limits shown in the sketch at post #21 (except for the obvious limitation on structure within the articulation path of the short tubes).

This leaves us with about 1-1/2 inch for the height of the Rack & Pinion mechanism (1" up from plywood to top of the long 1" tube plus 1/2" above the long 1" tube). This is because the "working end" of the higher pivoting linkage bar (where it connects to the short 1" tube) must always be higher that the point where it connects to the rack, otherwise, the mechanism would not allow the lid to be completely closed.

To understand this, you need to construct the cardboard mock-up I suggested earlier.

Please see the attached sketch to understand the following;

View A is what I understand from your most recent sketch, which allows only 1-1/2" height for the Rack & Pinion mechanism.
View B allows 2" height for the Rack & Pinion mechanism if the 1/2" plywood can be installed as shown.
View C allows 2-3/4" height for the Rack & Pinion mechanism if the 1/2" plywood and the 3/4" base can be installed as shown.

The more space that can be made for the mechanism, the more options you have on off-the-shelf hardware that can be made to work. You do not want to limit yourself any more than absolutely necessary... Also, the more space available, the more robust (stronger) the components can become.

 

[cybertron]

Tyroman

Enclosed in your 3d image and A as what i have to work with.

Endclose is a new 3d image I drew too explain the area i have to work with do to the structure to the wall and where the square tubing must be attach to the floor of the 1/2 inch plywood base.

This long sq 18'' tube, I might beable to attach a 1'' wide piece of plywood 18'' long under the tube about 3/4'' inch thick. would this help. can the plate be attach to the plywood base.
If this can't work then what can be done for the mechanism to work.

also how much more can the plate extend above the short sq tubing without interfering with the opening and closing of the two doors.

 

[cybertron]

tyroman

Have you seen my latest post

 

[tyroman]

cybertron,

To aid you in your understanding of machines, I recommend the article found here:

http://en.wikipedia.org/wiki/Simple_machine

Your posts #51 and #53 reveal several points which make your project more difficult...

1. The doors weigh twenty pounds.
2. The mechanism and its motor must fit in a space 2" wide by 18" long.
3. The mechanism can be no taller than 1-1/2"

The weight of the doors is a problem because the mechanism will have very little mechanical advantage. This is because the linkages will be attached to the short square tubes relatively close to the hinges. To lift twenty pounds without bending, the mechanism will need to be stronger than dimensions may allow.

The 2" by 18" footprint for the mechanism and its motor is a problem because the motor will have to be very small to fit in a space less than 2" wide. A small motor which might fit will probably not have the power needed to open the doors. The 18" restriction will prevent a larger motor being mounted off one end of the mechanism (as I previously described for the Worm Drive alternative...).

The 1-1/2" height limitation on the mechanism is a problem because it forces you to use a very small rack and pinion assembly, which (if one can even be found) will probably not have the structural strength to do the job without bending (or stripping gears).

***

There are some things that could address some of the problems which your most recent posts have uncovered:

1. Lighten the doors to reduce the forces on the mechanism and the power required of the motor.

2. Significantly increase the vertical space available for the mechanism so it can be made larger (therefore; stronger).

3. Increase the 2" by 18" footprint for the mechanism and its motor to allow a larger motor to be installed.

***

I have attached two scaled sketches based on the current limitation to 1-1/2" for the height of the mechanism. As shown, the Pinion can be no larger than about 3/4" diameter and the racks no more than about 3/8" tall. Only the approximate length (3-3/4") is shown for the linkages.

Think about what can be done to change the current "givens" for your project so we can have a better chance to make it work.

 

[cybertron]

Tyroman.


Yes i will read the link that you provided.
Yes the total weight of both doors is appox 20lbs. #51
Yes the mechanism and motor that I use must fit in the 2''x18'' limited space.

These are the givens that i mentioned.And that you pointed out.

What I could do is this.

1.Yes I could use mechanical means to reduce the weight of the doors
with counterweights or springs and this will reduce the Force to torque ratio of the motor that is used. How much weight would I need to drop! 5,10,15lbs.

2. Vertical height could be increase to about 8'' with a plate that could be bolted to the wooden base to hold the rack mechanism as close to the bottom of the 18'' long tube as indicated in my enclosed edit image ''but how would the gear be attached, or would it still be attach to the longer tube or to a plate where the rack would be mounted too, and it must not interfer with the closing and opening of the shorter tubes.

3.Increasing this area the 2'' x 18'' space as you stated, this CANNOT be changed at all.There is no way it could be done.As indicated in image.

4.The large Tube could be lifted up with another piece of wood to about 3/4'' to give it more height from the woodbase if needed.As stated in #53.

5. I wouldn't know how to compensate for both of the linkages length do to the 18'' limit in the 2''x18'' space as indcated in my 3d image.BUT I guess this would change once the height changes with the rack or plate I'm assuming.

I'm getting a surplus GEARmotor that's strong for its size, its about 3'' long total, it was used in a tripod that turned a 40lb telescope AND has 6RPMs which is plently to turn from 0-100dgs in a short period, I THINK it has about 1.08watts of power.
I think it could fit somewhere in that 2''x18'' space so the force vs torque ratio would be covered.

I have no idea which pinion gear to use with the racks for this mechanism and the pitch of the teeth for both. I would need help in choosing them.I have no clue what to use.

So this is what I throught about in changing some of the givens for the mechanism in my project.

Tyroman.
Will these changes work for the mechanism to function properly and for added strength.

 

[tyroman]

cybertron,

Please post a sketch of your project as viewed from above... showing all dimensions and components. Include the two doors and how they will be attached at both ends. Also, please show how the 3" long motor will be installed in a 2" by 18" space. The doors (which are 10 pounds each) must be attached to something besides a single 1x9 tube at one end... please indicate what happens at the other end.

I have attached a sketch to get you started... please edit it and attach it to your next post.

 

[cybertron]

tyroman

The image you have posted is the Plan view. If you looking above.. that's what the plan view will look like as you indicated.

The two doors will be attach with my tubular bar lifter only on one side to lift both doors, this is the reason and purpose for the lifter and mechanism is too lift both doors at the same time.
That lifter will lift and hold more then 200lbs with the right motor.My doors only weight 20lbs total.The motor will hold the mass of both doors at any angle as indicated.

Other end must be clear of all objectsto gain acess to storage entrance.There is nothing else being attached to the other side...thee Lifter, and mechanical weight reduction to the doors would accommodate for the mass of the doors if needed.

All components are indicate for the lifter as preposted,anything else that would need to assist in lifting the door like springs or counterweight and there calculations will be my concern.

As for the motor not fitting in the formention space I will chip out some of the wall if needed to accommodate for the motors placement in that space, But only for the motor.
That (wall) was an old wood burning cooking fireplace from the 1800s that's been closed in with cement.

All electrical and electronics is my concern for the motors operation.

The Mechanism
All dimensions,rack and pinion parts,plate,and motor attachments for the mechanism to be attached e lifter is what i need.


link: Would this help you in choosing the rack and pinion parts.

http://www.mcmaster.com/#racks-and-pinions/=439d3f"

 

[tyroman]

cybertron,

We are not yet at the material selection/purchase stage of your project...

The first thing to do is adjust your design to allow as much vertical space for the mechanism as physically possible (The current 1-1/2 " is far to small). This will involve raising the tubular frame as high as possible above the ground to allow the rack and pinion components to be as large as possible. The highest point of the mechanism must be as far below the short tubes as possible. The mechanism can absolutely NOT extend ABOVE the short tubes. See my full mechanism sketch at post #55, where the linkage from the left rack to the left door slopes upward to the left. This requirement has to do with the Free Body Diagram which will apply for this device and will determine the mechanical advantage of the system of third class levers which the mechanism reduces to. This, in turn, will determine the strength and size of the components and the power of the motor which will work.

The second thing to do is develop the "counterweight" scheme which will (to the extent it reduces the load on the mechanism and motor), have significant impact on what components will work for you.

If this project involved designing an optimal mechanism and selecting the most economical components to do the job (which would then be put into mass production) it would justify the effort to fine-tune the design... however, this is a one-off situation and your best bet is to give yourself the maximum flexibility in component selection and then buy the largest (strongest) components which will fit. You do not want to invest your money in a fine-tuned design and then have it break after 10 cycles.

To help you understand my reference to a Free Body Diagram, I have attached a sketch. To get an idea of what the sketch depicts, try lifting one of the 10 pound doors at a point one inch from the hinge (which is where the linkage will attach). You will have to apply about 40 pounds of force to start the door in motion. Much greater force would need to be applied by the linkage, since most of its force is directed horizontally at the start.

 

[nvn]

cybertron: The attached file illustrates how the mechanism in my post 14 diagram works. (The image is stretched in the y direction for illustrative purposes only.) Study this diagram to see how linkages AB, BC, and CD move, and to see how they operate the right-hand door when you rotate the left-hand door. In this image, I rotate the left-hand door 360 deg, just to make it interesting; but your door will rotate only the first 100 deg, which is included here. You can make the image repeat in your viewer by selecting Play > Repeat, or View > Loop.