How does the opening, closing, locking mechanism of a window work?



I’m trying to fix a window that’s stuck closed and thought it would be to understand how it worked first, though I’m unable to find any information.

You’ve got the window handle which you push the button in, rotate the lever and push the window open. I believe there’s some mechanism inside which controls all this.

I know from my own window there’s this flat metal part that comes out at the top of the window that holds the window in place while the window is closed. I imagine there’s a lock inside that keeps this from moving while the window is locked.

I know there are also these circular what I think are called “locknuts” which go up and down on the side of the window as you rotate the lever.

Any more information on the inner workings of a window would be great.

In: Engineering

There are three dominant types of opening windows:

* **Sliders** – these simply slide back and forth along a track. They simply sit in the track groove, held in only by friction. They can usually be lifted straight up and out with little resistance.

* **Hung** – like a slider, but vertical. To counteract the weight of the window when the sash (the moving part) is lifted open, the sash is connected to cables on the insides of the jambs (the sides of the frame). In older windows, these cables lead to a pulley with heavy weights dangling from the other end, counterbalancing the sash. In modern windows, it’s a coiled strip of metal that behaves kind of like a retracting lanyard or a seatbelt.

* **Casement** – these windows are the ones that swing out, as if on a hinge, but they aren’t really hinged in the way you may think. The sash is attatched to the frame only on one side, and it’s free to rotate about this point (like a hinge) and it’s also able to slide back and forth (like a slider). There are linkage arms at the top and bottom that attatch to the sash, usually near its middle, and link to the top and bottom jambs on the side opposite the sliding hinge. It’s designed in such a way that if you try to pull the sliding hinge inward to the center of the window, the linkage arms force the sash to swing outward. The crank you turn is linked to a lever arm that does exactly this: it tugs the corner of the sash, sliding it toward the center, and the linkage arms on the other side force the sash to swing out. Turning the crank back does the reverse: pushes the slider back to the edge of the frame, and the linkage arms will suck the sash back snug into place.

I assume what you have is a casement window. If the window isn’t too old, try to find any details of the manufacturer. They usually hide a sticker somewhere in the frame, or in the tiny gap between the panels of the glass. The manufacturer would likely be happy to assist with troubleshooting your exact product.

Source: worked for a window factory for a couple months.