ᐅ Mushroom-head window lock

Created on: 6 May 2016 23:35
M
merlin83
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merlin83
6 May 2016 23:35
Attached are 3 photos showing the bottom edge of the window and the bottom edge of the frame.

In the photo, there are 3 mushroom head locks visible and on the frame, 2 fittings. The fitting on the left looks different from the one on the right. What has been done here?

View through window onto white transport van side with wheel arch, next to a car


Long metal frame at a construction site with WIKKA fitting; next to it an orange cable reel.


Interior view of shell construction: brick wall with visible joints and installation channels
Mycraft7 May 2016 09:27
Note: Only partially trained knowledge:

It depends on what was ordered. The hardware on the right is designed for the mushroom cams. The one on the left is just a guide to pull the window closed.

In the standard version, there are usually 4 mushroom cams, while the rest are “regular” locking pins and rollers.

Mushroom cams have manufacturing-related rebate clearance tolerances. If only mushroom cams were used, the hardware would wear out quickly and the window would be very difficult to open.
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merlin83
7 May 2016 09:35
I originally only ordered 2 mushroom head locks per window. That’s why I’m surprised that so many mushroom heads were installed on almost all the windows.

I. Does having many mushroom head locks as a result make the window harder to close?

II. Can you improve burglary resistance simply by replacing the left hardware with one like the one shown on the right in the picture?

Thank you in advance.
Mycraft7 May 2016 09:42
Also just acquired knowledge again:

1. Yes, since the adjustment effort increases and you create two points where the window sash is fixed when these points are aligned on the same line.

In other words: if there is only one mushroom bolt on each side, the sash can be “pulled tight” by the sliding elements because only one point—the mushroom bolt—is fixed. This is called fixed or sliding bearing in structural engineering.

If you have two fixed bearings (mushroom bolts) on the same line, the window can only move along that line. This means that the window will only close tightly if it is adjusted perfectly—1000% correct. Any deviations, such as manufacturing tolerances or normal wear and tear, will cause the sash to become leaky.

2. Yes, but as explained in point 1, it involves an increased adjustment effort.
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redtatoo
9 May 2016 00:47
Mushroom head locking bolts are generally installed in the sash. In the past, standard sliding bolts were used for regular windows, while mushroom head locks were used for windows with security requirements. This is no longer done today for the sake of standardization.
Standard strike plates and security strike plates are installed in the frame (see photo). The front two mushroom heads shift to the left or right depending on whether the sash is tilted or closed. This means that one of the bolts engages the security strike plate from the side. The rotational position is in the middle—no mushroom head is engaged in the security strike plate. Due to the shape of the mushroom head, it cannot or can only hardly be pried out of the security strike plate. However, it can be pried out relatively easily from the locked standard strike plate.

You probably have another security strike plate further up or at the top front on the handle side. Everything on your windows is in order and as it should be.

Yes, the more security strike plates instead of standard strike plates, the greater the protection against burglary. However, the required force to operate the window increases slightly due to the friction. The mushroom bolts installed in your window are movable to compensate for any sash clearance tolerances.
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merlin83
9 May 2016 07:26
Thank you for your detailed explanations.