Need Help Mechanical double lid lifter

[nvn]

Something might be workable. I might investigate a symmetric version of something somewhat similar to posts 68 and 10.

 

[cybertron]

nvn

OK.That seems knid of interesting meshing post 10 and 68 into in someway.

I looked at the space much closer, if the motor that i will using is placed length wise as indicated in post 82 that will limit the lenghts space from 18'' to 14'' deducting 3'' for the motor that's including the shafts length on the motor, (plus 1/2'') on each side for any variances for adjustment that's tight,So if you keep or place the motor like in post 82 that would be OK ''but, there will only be 14'' left for any placement of a symmetric mechanism concept in that area but you will have the 3'' in height do to the added spacer as indicated in post 67.

Maybe the parts that tyroman suggested could help with the symmetric design where it could fit and will work.

 

[nvn]

I now found a solution using my asymmetric post 14 design concept. The attached video file, below, shows how the mechanism works. Study this file to see how linkage bars AB, BC, and CD move. In this video, I rotate the left-hand door 100 deg, which causes the right-hand door to rotate 101.4 deg. You can make the image repeat in your viewer by selecting Play > Repeat, or View > Loop. The support blocks for linkage bar BC are shown at points E and F in my post 14 diagram.

For the design shown in the attached video, the (x, y) coordinates, in mm, of points A, B, C, and D when the doors are at 0 deg (closed) are A(17.00, 25.40), B(164.83, 0.00), C(414.83, 0.00), D(477.00, 0.00). The coordinate system origin is located on the left-hand end of the long square tube, at the tube longitudinal centerline. The linkage bar lengths (from pin centerpoint to pin centerpoint) can therefore be computed from the above coordinates, and are |AB| = 150.00, |BC| = 250.00, and |CD| = 62.17 mm. The long square tube is 460.00 mm in length.

The drive mechanism for this design is shown in the attached .png file, below. The .png file shows a side view of the mechanism, and a partial bottom view.

See all my previous posts for a detailed description of this design. All of my parts 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 is also outside.

Notice in the video, the brown plate at point D interferes with the bottom face of the long square tube. Therefore, you might need to cut a slot in the long square tube if the brown plate interferes, unless a refinement in the exact dimensions (such as adding the hinge thickness, etc.) resolves the problem. The above coordinates currently assume coincident tube faces, as shown in the video. I.e., no allowance is currently given in the above coordinates for hinge thickness, because an exact hinge thickness in mm has not yet been given.

 

[cybertron]

nvn.

Will this design solution work and function as stated, is this the finished design. Can I start asembling the mechanism.

Also I'M not do sure about where these two number indicator at.Please explain!
When the two doors are in the 0deg closed position, on the x y corrdinates for point A these two numbers 17. 00 and 25.40 are placed where on the shorter tube.

As for the flate bar material what do you think i would need in size and thickness because you didn't not state this for in side the tube.

I did find on-line Alumimum flate stock and steel, sizes 1'',1/2,3/4'' 5/8'' wide and for the thickness 0.05'' 3/16'' or 1/8''. what material would be the way to go steel or alumimum.

In post 68 and 94 in the drawing this part in the low bottom right.Please explain.

What is the brown plates dimensions was not mentioned.

I'm assumming the thinkness for the hinges is appox .2'' 0r 1/16'' have not purchased any hinges yet.

 

[nvn]

cybertron: No, the design concept is not finished yet. Let's first try waiting for three or four days to see if tyroman has comments.

 

[cybertron]

cybertron: No, the design concept is not finished yet. Let's first try waiting for three or four days to see if tyroman has comments.

OK. I will wait

 

[tyroman]

nvn & cybertron,

My comments will be brief.

Nvn, have you done any calculations to establish the forces which components of the mechanism must withstand? Do you believe that cybertron's motor will be powerful enough? (see my post about the free body diagram).

cybertron, as I understand nvn's design, manual operation and motorized operation of the doors are not independant. In other words, if the doors have been opened by the motor, they can not be closed by hand (distinct from use of a hand crank which you rejected when I suggested the worm-drive design). The motor (or a crank) will have to be used to close them. Are you OK with that?

In general, nvn's design appealed to me when I learned that the doors weigh 10 pounds each. This is because his simpler design had an advantage over the rack and pinion design since it would allow larger (stronger) components within the limited space available (about 3" from bottom to top). However, if his current design is installed inside the 1" square tube, that advantage is lost.

Lastly, for cybertron, I'm confused that you seem OK with the parts of nvn's design which occupy space in the "off-limits" area which you have defined. Neither the motor nor the link attachment point at "D" are within your 2" x 18" work area.

 

[nvn]

tyroman: I have not investigated nor considered motor power in any way. Yes, I did a very preliminary calculation of linkage bar axial force for the post 94 mechanism. Neglecting hinge thickness, neglecting short square tube self weight, neglecting hinge friction and friction at support blocks E and F, and assuming a door weight of 44.48 N, I got a very preliminary maximum linkage bar axial force of 409 N tension, and 332 N compression. These are the maximum axial forces in linkage bars AB, BC, and CD. The maximum axial force in linkage bar HB would be close to 409 + 332 = 741 N tension, neglecting the aforementioned items. In the future, if I have time, I will assume and implement a hinge leaf thickness of 2.10 mm (total hinge thickness, 4.20 mm), which may slightly alter these force values.

 

[cybertron]

tyroman

I assumed that nvn design could be opened by handcrank, hand manually and motor stated in his design as well as with a the motor. If his post 14 revised design cannot be open or closed by hand but only with a motor, if that's the case, is it because the mechanism is on the inside of the long tube or will it work if the mechanism was on the outside of the longer tube or is it the limited space available.The 18''

Also by looking closer at nvn revised 14 design I don't think there would be any room for the motor if the mechanism is located inside the 18'' long tube and that would be the entire length of the tubes space. How would a motor fit and work if the motor was to be inline with the 18'' long tube this would extend that length to 21'' plus, which dose infringe on the off-limited space as you stated tyroman. I do see this.

tyroman Yes i did reject the hand crank. Reason for this was stated in one of the post i posted. Security, Time it takes to open the doors with a handcrank and anoption to use a motor. Now looking closer at the space that's available
18'' in length there's only 2'' in he width for a Handcrank to turn if it sits an the bottom of the woodbase and inline at the end of the long tube.

If nvn can made the mechanism that he revised that's inside the longer tube and includes the motor, But dose not extend the mechanism length into the off-limit space and can made the doors open and close by hand as well with the motor but off-sets the position of the motor to the side of the 18'' long tube, would this work.

If the doors cannot be opend or closed by hand or with a motor independantly then a motor would be used to open and closed the doors.

Tyroman Is there a way to use nvn design on the outside of the long tube and have it open independantly by hand but without a so call handcrank mechanism. I did like what you suggested by using bevel gears to move the bar in nvn design is there a way to still make that work in nvn revised #14 design.

Also. i need a design that dose not use any custom forged parts. All parts must be off the shelf readly available.


The motor that i have can lift 75 in lbs meaning it can lift 75lbs to 80lbs maximum and hold it one inch up from the front of the Box do to the high gear ratio this was stated by the vendor where i purchased the motor from.

Is your rack and pinion design still being work on. I still need a mechanism to construct.

 

[tyroman]

cybertron,

I have attached a sketch made from a snapshot of nvn's first animation and one of his motor drive sketches. Two areas are highlighted with GREEN to indicate the parts of his design which would be in the "off-limits" area, outside of the 2"x18" area you have established.

As I understand your last post, you did not realize that the motor would be in the off-limits area and you now want to know how nvn's mechanism could be motorized differently. What about the other location (at link CD) where the mechanism is "off-limits"? If this is NOT acceptable, then nvn's entire concept may have to be re-thought and the exercise of re-designing its motorization could be wasted effort.

Please consider the above and decide what is acceptable to you.

If you decide that link CD being off-limits is acceptable and still want to know if the motor could be made to work within the 2"x18" area in some way; my answer to that question is a qualified NO. This is because, with the linkage BC INSIDE of the long 1" tube there would be very little room for a gear to be driven by your motor. If nvn can re-design his mechanism to be mounted OUTSIDE of the long 1" tube, then YES the motor might be easily connected. This is up to you and nvn.

Note; CAPs above are for emphasis... not a shout.

PS; in future, I suggest you print out the sketches posted by nvn or me and take the drawing to your nearest auto mechanic or hardware-man so they can help you understand what the sketch is showing.

 

[cybertron]

tyroman

Yes the green circles indicating the off limits: Went nvn posted the video I didn't think at frist if that would be a problem until I looked closer at the limited area available for the long tube and by watching the video many more times.

I think the reason why nvn had not gotten the doors to open and close in uinson,and at 90degs is that he needed more mounting space to extend the mounting points for the required angles with that extended plate so that the doors would open at the 100 and 101degs in the revised video.This is my understanding in the video.

This is why i didn't realize that the motor would be in line with the longer tube and extending the 18'' to 21'' plus.
The other location at (CD) would be acceptable if the extended brown plate is not more then 1'' in width I could adjust for this.
I cannot adjust for the other side where the motor is place inline with the longer tube there would be no room to fit the motor there that would make it well over 21''. That would be unacceptable.


Yes. Points CD is acceptable.Only if the extension with brown plate is no more then 1''
No. Motor placement in off-limits area, its indirect line with the long tube unacceptable. It would extend beyond the 18''. not enough room.

Enclosed image: Arrows show what's Acceptable and Unacceptable.

 

[cybertron]

nvn


There seems to be a problem in placing the motor inline with the longer sq tube.Did you know that there are off-limt structural areas in the space i have available to place the mechanism to the lifter. The area is 18'' x 2'' so the mechanism can not be beyond the longer tube which is 18''.


I thought that the motor would be within the 18'' length of the longer sq tube in your design #14 #98 But it extends beyond that which would make it over 21'' which would be unacceptable beacuse there's not enough room to place the motor inline with the long tube.

I realize this by looking closer at the available space i have and by watching your original 14 post and the new revised design on the video in post 98

Also tyroman pointed this out to me as well! He include a edited snapshot of your revised video in post 101 to show me that the revised design would extend beyond the 18'' and into the off-limited areas.

So please read tyroman post 101
And my post 102 as what I will accept and can not accept in your revised design.

There might be a solution to the motor placement to the revised design by placing the mechanism on the outside of the long tube instead of inside. As tyroman suggested.

The Enclosed image could be an option for motor placement but the longer linkage bar in your design may need to change to a rack as indicated in image.

nvn
Please look at my post 67 and post 82 for off-limits areas and available space I have to work with in this project.

Tyroman is that any other option that you can think of where nvn revised design can still work with new placement of the motor I'm using.

 

[nvn]

My linkage system is essentially independent of the drive mechanism. You could drive it in any way you choose. And, my linkage system is perhaps somewhat independent of whether you choose to mount it inside or outside the square tubes. Therefore, I will cover only the independent linkage design herein.

I now implemented a hinge plate thickness of 2.10 mm (total hinge thickness, 4.20 mm). Therefore, the attached video file, below, now contains very accurate, exact geometry, whereas the previous videos did not. I also attached, below, a .png file, which includes the support blocks.

For the design shown in the attached video, the (x, y) coordinates, in mm, of points A, B, C, and D when the doors are at 0 deg (closed) are A(10.00, 29.60), B(157.05, 0.00), C(417.05, 0.00), D(480.00, 0.00). The coordinate system origin is again located on the left-hand end of the long square tube, at the tube longitudinal centerline. The linkage bar lengths (from pin centerpoint to pin centerpoint) can therefore be computed from the above coordinates, and are |AB| = 150.00, |BC| = 260.00, and |CD| = 62.95 mm. The long square tube is 460.00 mm in length. The coordinates of the hinge rotation centerpoints, called points J and K, are J(-5.00, 14.80), K(465.00, 14.80). The centerpoint coordinates of support blocks E and F are currently E(180, 0), F(365, 0); and the support block length is currently 14 mm. The gap between the long and short square tubes when the doors are at 0 deg (closed) is 4.20 mm.

Assuming a door weight of 44.48 N, I got a maximum linkage bar axial force of 429 N tension, and 336 N compression. These are the maximum axial forces in linkage bars AB, BC, and CD. The maximum axial force in linkage bar BH would be 750 N tension. The required door opening force applied by a human at the inner edge of the left-hand door is 57.2 N when the doors are at 0 deg. The above force results include hinge friction and support block friction.

Therefore, due to the above force results, the cross-sectional height of each linkage bar is currently 5.0 mm. The cross-sectional width of each linkage bar layer is currently 2.7 mm. In other words, the cross-sectional size of linkage bars AB and CD is 5.0 mm high by 2.7 mm wide. The cross-sectional size of linkage bar BC is 5.0 mm high by 5*2.7 = 13.5 mm wide. The linkage bar (and square tube) material is mild steel. The governing stress is currently linkage bar AB buckling stress. I used an ultimate factor of safety of 2.0.

I have assumed the door system is operated in a slow, normal manner. I currently have not assumed adverse conditions, such as gale winds, nor human misuse of the system, such as opening the doors far too fast. Therefore, the listed linkage bar cross section sizes constitute a minimum.

 

[nvn]

The drive mechanism cannot be in-line beyond the long square tube.

Here is a new drive mechanism concept. To open the doors, rotate the 6.35 mm square drive socket head counterclockwise. Remember, this diagram is not to scale. Use the coordinates listed in post 104 instead. The coordinates of points A, B, etc., in post 104 are exactly to scale. You can mount the linkage mechanism inside or outside of the square tubes, whichever you prefer. Let's see if tyroman has comments.

 

[cybertron]

nvn

The change for the drive mechanism could work, But only if the motor is placed and some way connected in parallel to the drive gear mechanism do the width in the available space. If you look at post 67 the width is 2'' wide from the tube to the wall and the motor is 3'' long so the motor cannot be connected directly inline to the revised drive mechanism.
Is there a way to connect a right angle drive gear between the drive mechanism and the motor to drive the revised drive mechanism. Maybe tyroman has a way to drive the motor opposite (parallel) to the revised drive gear mechanism.

 

[tyroman]

nvn,

Very clever arrangement... however, at least one problem would arise when the doors are opened beyond 90 degrees with the spool mechanism. The twine(?) would lose contact with the pully at H and the doors would then have to be manually closed (at least until they reach 90 degrees or less).

Another potential problem might occur if the doors are opened and closed repeatedly by hand... could this cause the twine to become fowled?

Also, if this double spool arrangement is mounted outside of the long 1" tube, (allowing access to the twine for maintenance) the assembly will occupy a lot of the available 2" space and a right angle drive for motorization might not fit.

cybertron,

You might think about what you said in post #67;

"the door will sit at the lowest point of the 3'' height of the tubing.That not a major problem to change."

See attached sketch. The "possible solution" shows a new strip of wood attached to the right door which would over-lap the left door, covering the gap.

 

[cybertron]

tyroman

Why do I need to rethink post 67

In post 67 the doors do lay at the level of the plywood base and that's 3'' below from the top of the shorter tubes to the base do to the spacer added for your rack and pinion design mechanism this is why I add the spacer for the stability and for added strength in your rack and pinion design as you suggested for the added height for the rack and having a stronger design. At this time which is not being considered anymore as a design, but might of worked.
I haven't heard from you for sometime now about this proposed design.So I'm asumming this is not an option anymore.

In your latest 3D image of where the doors sit (they do sit right at the level of the plywood base): and leveled with the bottom of the longer tube
as indicator in your last image at the bottom part of your sketch.


Now. Why would i need to cover the gap between the two doors.There must be a gap between the two leaf doors for expansion and contraction and so the doors do not hit each other when opening/closing.
So why would I need to add a strip of wood on the right side of the door laping over the left door to cover the gap.There could be a problem with adding a strip to the right side of the door, say the left door opens before the right door dose and hit the right door by 1sec asummuing the left door opens first.
Explain the reason why this wood strip is to be added on the right side of door, and for what purpose.
I'm asumming this is added so nothing falls through the gap or for aesthetics.

 

[nvn]

When the doors are opened beyond 90 degrees, ... the twine(?) [cable] would lose contact with the pulley at H, and the doors would then have to be manually closed (at least until they reach 90 degrees or less).

tyroman: Very observant. Good catch. And I notice my previous drive mechanism in post 94 exhibits this same problem.

 

[tyroman]

Corrected diagram for discussion...

 

[cybertron]

tyroman

What do i need to do and need to know about this image in post 110.

And are you still working on the rack & pinion design Yes or No.



nvn

Have you're come up with any new ideas or changes for the motor drive mechanism in your latest revised design in post 104.

 

[nvn]

cybertron: Don't worry about the image in post 110. It is a free-body diagram by tyroman of the left-hand door.

My latest concept is shown in the attached diagram, below. Not to scale. The red part is a U-shaped plate. The bottom of the U is underneath linkage bar BH. Only if the doors are being opened by the motor, then the two uprights of the U actuate the green compression springs, beginning when the door angle is 85 deg. The red U-shaped part does not engage the springs when opening the doors manually. Let's see if tyroman has comments.

You can use right-angle, helical bevel gears to rotate the drive mechanism, if you wish. You can mount the linkage mechanism inside or outside the square tubes, whichever you prefer. If the mechanism is mounted outside the square tubes, the spool can be quite narrow.

 

[cybertron]

cybertron: Don't worry about the image in post 110. It is a free-body diagram by tyroman of the left-hand door.

My latest concept is shown in the attached diagram, below. Not to scale. The red part is a U-shaped plate. The bottom of the U is underneath linkage bar BH. Only if the doors are being opened by the motor, then the two uprights of the U actuate the green compression springs, beginning when the door angle is 85 deg. The red U-shaped part does not engage the springs when opening the doors manually. Let's see if tyroman has comments.

You can use right-angle, helical bevel gears to rotate the drive mechanism, if you wish. You can mount the linkage mechanism inside or outside the square tubes, whichever you prefer. If the mechanism is mounted outside the square tubes, the spool can be quite narrow.

OK. Let's see what tyroman thinks.

I really don't get what the red part dose in both images or how its connected to the tube.

 

[tyroman]

nvn,

Another clever design... but I'm not sure how cybertron is going to find the spring/bracket assembly "off-the-shelf", though it reminds me of some spring-loaded cabinet door latches I have seen.

When the door is lifted manually from the closed position, tension in the cable would be released and your linkage bar BH would immediately drop down and subsequently the two uprights of the U would pass below the springs.

This would work fine; however, if I understand the mechanism correctly, the springs will supply a tensioning force to maintain cable contact with the pully at H when the motor moves the door from 90 to 100 degrees. Would the force they exert (when the motor is stopped at 100 degrees) then not be sufficient for the springs to independently tip the door back to the 90 degree position from which it would fall closed of its own weight? This assumes that the motor (including its gear box and any right angle drive connected) can be driven in reverse via a force exerted on its output shaft... an assumption which is necessary for manual and motor operation to be independant. I suppose it might be possible (if the springs are sized very carefully) to find the fine line between operation as you envision it and the scenario I describe.

My comment above reminds me of something cybertron has said in an earlier post which has troubled me;

#58 "The motor will hold the mass of both doors at ANY ANGLE as indicated."
and,
#33 "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."
NOTE: I added CAPS above to highlight the phrase of concern.

If, for example, cybertron wants to be able to open the doors to 60 degrees by hand or motor and have them remain there without further input, then some sort of counterbalance system or arbitrary frictional force will need to be introduced into the design.

 

[cybertron]

nvn,

Another clever design... but I'm not sure how cybertron is going to find the spring/bracket assembly "off-the-shelf", though it reminds me of some spring-loaded cabinet door latches I have seen.

When the door is lifted manually from the closed position, tension in the cable would be released and your linkage bar BH would immediately drop down and subsequently the two uprights of the U would pass below the springs.

This would work fine; however, if I understand the mechanism correctly, the springs will supply a tensioning force to maintain cable contact with the pully at H when the motor moves the door from 90 to 100 degrees. Would the force they exert (when the motor is stopped at 100 degrees) then not be sufficient for the springs to independently tip the door back to the 90 degree position from which it would fall closed of its own weight? This assumes that the motor (including its gear box and any right angle drive connected) can be driven in reverse via a force exerted on its output shaft... an assumption which is necessary for manual and motor operation to be independant. I suppose it might be possible (if the springs are sized very carefully) to find the fine line between operation as you envision it and the scenario I describe.

My comment above reminds me of something cybertron has said in an earlier post which has troubled me;

#58 "The motor will hold the mass of both doors at ANY ANGLE as indicated."
and,
#33 "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."
NOTE: I added CAPS above to highlight the phrase of concern.

If, for example, cybertron wants to be able to open the doors to 60 degrees by hand or motor and have them remain there without further input, then some sort of counterbalance system or arbitrary frictional force will need to be introduced into the design.

In post #58
I stated that do to the information that I gotten from the vender i purchased the motor from they stated the motor will hold both of the doors which is 20Lbs total which the motor would handle up to 75lbs in oz holding 75lbs the lid 1'' above the opening. So I'm assumming the the motor will hold the weight or mass of the door at the 0-90degs suggested by the vender.
In post #33 as stated But what I was try to say is..
The side that's lifting one door by the motor or by hand that the oposite side lifts up the other door at the same time do to the assistance of the small bar on on the other side of the lifter so both doors open and close from 0-90 or 0-100degs in unison...

Opening the doors from 0-100 degs is fine.
I don't think i would need to open the doors at 60 degree.

tyroman:Sorry If this troubled you. what I was stating is that the doors when opening at the angle of rotation from 0-100 degrees they open in unison and not stop at any certain angle but rotate thru the 0-100degree angle of rotation. if this makes sense.

 

[nvn]

tyroman: The spring force would be designed to be just sufficient to rotate the doors from 100 deg to 85 deg, which is much less force than the drive mechanism applies, and much less force than is applied when the doors are at 0 deg.

Good point regarding your comments in post 114. A motor with a built-in locking device would perhaps be required. When power is supplied, a built-in solenoid in the motor would disengage the locking device, allowing the motor shaft to rotate. When power is removed, the locking device would automatically retract to the default, locked position. Maybe the designer can find a motor like this; I do not know the details. Otherwise, locking a door open manually would be required, such as using a prop bar; however, this might be cumbersome. The designer can implement any operational details desired. It is up to the designer to work out the intricate details of the design.

 

[tyroman]

cybertron,

You said;
"I really don't get what the red part dose in both images or how its connected to the tube."

The red part is not connected to the tube, it is connected to link BH. As the motor raises the door, the red part engages the green springs which ARE connected to the tube. As the springs are compressed, they exert a force to the right on link BH, keeping the purple cable taut.

See my edit of nvn's sketch attached. Note; the solid green blocks represent the fully compressed springs with the door open to 100 degrees. Also, the upper part of nvn's sketch is the side view of the mechanism while the lower part is the same mechanism viewed from below.

You also said;
"Opening the doors from 0-100 degs is fine.
I don't think i would need to open the doors at 60 degree."

Good! A mechanism which would allow them to STAY at any position except 0 degs or 100 degs would be more complex, as nvn stated in his post #116.

In answer to your earlier question... no, I have gone no further with development of the double rack & pinion idea. As I have stated before, I feel that nvn's design will be cheaper, simpler for you to build and (potentially) more robust than the rack and pinion design. All that is needed is to come up with the way to motorize it.

 

[cybertron]

nvn

In post 105,104,and 112 are these drawings the final designs of the door mechanism including your motor drive mechanism concept in post 112. if not.Will there be any new changes.

In post 104 is this the final design door mechanism without the motor drive mechanism and if i construct this without the motor drive mechanism i would need to open the doors by hand. correct.

The design in 112 with the motor drive mechanism might not be as simple to build as i throught. That spring mechanism in the design is not a part i would beable to find off the shelf as tyroman mentioned, also the part that connects the spool to linkage (B) is a custom part which i got from two places who could make that part but its going too be very expensive to make about $300-$600 they will have to forge that part as a one piece item which I'm not willing to spend on one part.

The design in post 104 i think is doable and i think i might beable to construct it but without the motor drive mechanism in post 112 do to the parts which are not something that's going to be found off the shelf. I NEED a motor drive mechanism design that can be constructed with parts i could buy from hardware stores or online stores.
But don't get me wrong! the drive mechanism design in post 112 looks like a good design but its not an option that i would beable to biuld do to the motor driver parts

nvn do you have any other design options to drive post 104 with a motor but usig only parts i can get off the shelf.Not Custom.

Tyroman.

In your early designs could anyone of them be used that uses a screw drive be attach to my tubular lifter with nvn design in post 104. Without custom or hard to find parts. Any options.

 

[tyroman]

cybertron,

You ask;
"In your early designs could anyone of them be used that uses a screw drive be attach to my tubular lifter with nvn design in post 104."

If you mean "worm drive", no. The worm drive idea was discarded when it became clear that operation of the mechanism with a hand crank was not acceptable to you. There would be no other way to manually operate the mechanism if the motor is connected through a worm/worm-gear arrangement.

Among the various schemes I have offered, the "door-mechanism-05 (with motor).png" at post #83 would be my suggestion for motorization of nvn's design. However, it would require that his design be modified as follows;

1. mount the mechanism on near-side of long tube rather than inside
2. substitute a rack for his link BC

Also, my post #83 sketch contains no detail on the size or method of mounting or attaching the various components... Some further work would be needed before you would have all the info to buy and build;

1. The rack and pinion design strength calculations- [nvn or vendor]
2. The right angle drive or bevel gear strength calculations - [nvn or vendor]
3. The method of mounting the gear motor - [motor mount dimensions known only to you]
4. The method of attaching the various gears including a bearing assembly for the pinion gear mounted to the long tube - [follows decisions above in 1, 2 & 3]
5. Selection of rack guides/bearings to support link BC [follows decisions above in 1, 2 & 3]
6. Selection of link connectors for points A, B, C, and D [follows decisions above in 1, 2 & 3]
7. More?

Rack and pinion sets are available on-line, however they are not cheap. A set of appropriate size (strength) would need to be selected based upon nvn's calculated design forces.

I have attached a photo of a rack and pinion arrangement in a common bathroom scale for your information...

I understand from another thread that nvn may not have time in the next few weeks to visit PF... so, unless someone else comes to your aid on the points I've outlined above, you will have to continue to be patient.

Links to an on-line site with relevant equipment are listed below. This is for information only, so you can get an idea of what is available (and how much it may cost). Also see links I have provided in earlier posts.


http://www.sdp-si.com/index.asp

they sell gear motors;
http://www.sdp-si.com/web/html/Motors.htm
https://sdp-si.com/eStore/Direct.asp?GroupID=819
gears;
http://www.sdp-si.com/web/html/gears.htm
racks;
https://sdp-si.com/eStore/Direct.asp?GroupID=284
round racks;
https://sdp-si.com/eStore/Direct.asp?GroupID=501
https://sdp-si.com/ss/PDF/79001188.pdf
rack guides;
https://sdp-si.com/eStore/Direct.asp?GroupID=766
https://sdp-si.com/ss/PDF/78001137.pdf
linkage ends
https://sdp-si.com/eStore/Direct.asp?GroupID=1080

 

[nvn]

cybertron: The attached diagram, below, shows an alternate method, in which the axial springs are replaced by the green torsional spring. (If you use the torsional spring method, you will need a prop bar or locking pin to hold a door open, when opening the doors by hand.) You can use whichever method you prefer.

Yes, the linkage mechanism shown in post 104 is currently a final design concept. It has a motor drive mechanism shown in later diagrams, even though the motor drive mechanism is not shown in post 104. You can open the doors by hand or by motor.

The part that connects the spool to linkage B is a custom part...

The part connecting the spool to linkage bar BC is called linkage bar BH. Linkage bar BH is not a special part. It is relatively easy to make, and not expensive. It is simply two flat bars, a cylinder, and a pin.

 

[cybertron]

nvn


This torsional spring alternate replacement part, is it part of the hinge or a separate part that attaches to the hinge and will i beable to find this separate part or hinge from a online supplier.

Will this torsional spring be need if the drive motor mechanism attached to point BC linkage is not used as is in post 104. Or would i need to used the torsional spring no matter if the motor drive mechanism is used or not.

how would the cable be attached to the big spool to the smaller spool. if its attached to the in side of the longer tube its not going to be that simple to attach this inside the tube and how long would the cable need to be.The cable might not work correctly as suggested.this is my concern.Because there's always the problem getting the cable to work just right.

nvn
Can you LOOK into using the design in post 83 and make the modification but still use the design in post 104 with the required 104 design forces and calculations and suggestions as tyroman suggested in post 119.