Need help positioning linear actuators to a bi-fold window shutter model


I am trying to design sturdy tornado window covers for my home. They will be made out of 1-1/2" square tubing, and have a sheet metal steel face with a design cut into them with a CNC plasma table. A horizontal hinge in the center will allow the shields to fold up when not in use, and create a sun shade over the window. I want to use electric linear actuators to raise and lower them, so they LOCK in the lowered position, to also act as intrusion guards while I am out of town.

I created the guards, and I am an amateur at SketchUp, but I am LOST when it comes to the geometry of moving objects. So I am looking for someone who can show me how to attach the actuator and motor at the top, and retract the cover, with the top and bottom corners of the cover remaining on a single vertical plane. The top would be a hinge, and the bottom would be wheels that follow a vertical metal channel along both sides of the window frame. They would fold as “>”

The actuators are 4.77" + stroke+ stroke. So with a 16" stroke, they are 20.77" closed, and 36.77" extended. The window frames are 70" high. I could use shorter actuators if necessary. They are quite strong and there will be two on each window cover.

I saved the file as 42134 WINDOW SHUTTER. I don’t know if you can access the file which was created online.

I will check back soon to look for replies.


It would help to tell us more. Are you trying to create an animated SketchUp model? Or do you just want to position the actuators where they belong on the window frame? It would also help f you could share the model you’ve made so far; I think you’ll need to download the file to your computer and then upload it here on the forum.



I am trying to work out the geometry so the shutters will function properly when they are built. I don’t want to guess at where the actuators should be mounted in order to get the full extension of the actuators when closed, and the best closed position with the shutters raised open and the actuator is fully retracted.

I would like to see a visual animation of them before I spend the money to build them.

I do not see a way to download the drawing I made from the online Sketchup program.

Maybe a LINK to it??


Click on the file folder icon near the top and then Download.

Got it! So now I upload it to ??? (Looking …)

Just drag it into the forum reply window.

Ah! Thank you!

42134 WINDOW SHUTTER.skp (899.7 KB)

The top half is grouped with the top half of the hinges, and the bottom is likewise. I do not know how to LOCK the position of something so it does not move., or lock it to a certain axis. I am fairly amateur at this stuff.


The top will rotate at the hinge pin. I don’t know how to “anchor” the top so the bottom will pull up when the top is rotated, like a garage door opening up.

The way I would handle this is to put copies of your hinge component at the top of the upper panel. Maybe you’ll need different hinges but this is a start.

Then Rotate/Copy both panels up to whatever angle you are expecting for the top one.

Then rotate the lower one back.

This is a rough idea but you would work out where the center line of the track for the lower wheels is and figure out how high the wheels need to from the bottom edge of the panel.

For the rotations, make sure you are rotating around the center of the hinge pin. You might also find using the Arc tool which allows you to start from the center of the arc helpful in looking at the travel.

Thank you. There is a steel plate across the top of every window, to support the brick facade. I was planning to weld a top hinge to that plate, with the pin on the outer edge, so the frame will not bind when raised.

I can draw the hinges and the C channel track that runs vertically along each side of the shutter, to provide a channel for the lower wheels to follow as the shutters are raised.

Is there a way to RESTRICT the movement of the lower wheels to remain in the C channel as the shutter folds up? (Lock them to the Z axis?)

I could do all of this on graph paper, but the purpose of doing it with SketchUp is to learn the software. Once I get the shutter to fold up and down, the only task that remains is figuring out the length of the actuators I will use, and the mounting positions for the top and bottom that the shutter folds closed as much as possible. I hope to have nearly a parallel “sandwich” of the top and bottom halves when fully open.


The wheels would be at the absolute bottom. The frames will be designed so that sliding tubes INSIDE of the 2" frame tubes will slide down across the hinge joint, so that the shield becomes one solid plate that cannot be pulled away at the center hinge. To open, one actuator would raise the slides until they are pulled out of the bottom frame, and then the second actuator would fold up the shield.

This all sounds a little “zombie apocalypse”, but I have already replaces several expensive two pane windows after a tornado, so I figure this is insurance against future costs. It will also make the home far less vulnerable to burglars, although at the moment that is not an issue around here. I have 15 windows on my home, and 14 windows on a barn with guest bedrooms above, so I want to make these shields for all 29 windows, and four double dutch doors.

So as I work on it some more, I have added the top hinge and the frame. Also, there is a copy that is open added to the drawing.

The steel frame will be bolted to the brick facade on all four sides, and MAYBE welded to the steel top plate that supports the bricks over the open window frame.


42134 WINDOW SHUTTER 2.skp (1.2 MB)

Isn’t this tab going to collide with the frame as the shutter is closed? It already overlaps.

These will all be made out of stainless steel.


Yes, I did not bother to make that lower hing plate a unique component so I could shorten it to display it correctly, but that is not critical for this discussion. I can SEE these in my mind. I just want to figure out the geometry so they will fully open and close, and look good when open. They will cost a small fortune at nearly $350.00 per window, so I want to get these right the first time.

In order for the actuators to cycle through their full stroke and achieve the true vertical and fully folded positions, the anchor points are where it is critical. The actuators that fold the shields need to be positioned so that they do not bind or fail to fully open the shields, but will fully extend when the shields are in the vertical closed position.

Also, I am not sure how to add the actuators to this drawing, and have one end attached to the top half but able to rotate at the mount point, and have the ram of the actuator attached to the lower point, but able to rotate and remain in line with the upper half.

I know it CAN be done. I just don’t know SketchUp well enough to accomplish this. Once that is done, the animation will be easy to create, and then I can go buy the metal and start making them!

Once you sort out where the actuator’s attachment points are on the shutters in both the opened and closed positions, you should be able to measure the linear travel of that point and then determine the size of the actuator and where its fixed end needs to mount. If the shutter panels are to be flat (in the same plane) when in the closed position, how do you push the center hinge point out so the actuator can lift the bottom?

It might be easier to simplify your model to some lines and circles.

That is a good question! I am thinking of adding some strong springs across the back of the hinges that will apply a forward force on the joint when they are closed. At the moment the actuators “relax” and begin to lift, the springs will push the center hinge out enough to start the fold. It only needs the slightest bend to create the lift triangle. Your thoughts?

The “big idea” here is to have them close simultaneously, when the tornado sirens go off. I get a notice on my iPhone when the risk is there, so if I can set up … something … so that even if I am away, I can activate the shields (like Batman :rofl: ) and all of the window shields will roll down and lock into position. Alternately, I could use a simple wind speed monitor, and shut them whenever the winds are really strong.

I work this kind of mechanical actuation out for my work, I do use sketchup for much of it. The key is to set up your model with handles and guides in the correct positions of rotation so it can be easily and correctly manipulated. Use arrow keys to lock your rotation axis. Give your self guides to snap to as I have done by putting a line in the center of your wheel tack. Make it all a component and copy it out several times, then make each instance unique so you can manipulate it independently. Eventually you will create pie shaped arcs and lines that cover the travel distance which will give you your throw distance and the stroke area. BUt your current plan has some problems, I repaired the hinges a bit and grouped things better and added some wheels for experimenting. As you can see your bottom section is not long enough to stay in the track at full lift. Also these will be very shady unless they lift past 90˚. Most bifold doors of this type lift with cable winches actuating the bottom points (where the wheels are). These is a common setup for aircraft hanger doors.

42134 WINDOW SHUTTER 2.skp (1.2 MB)

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