Editing Mercury switch (section)

==Uses==
===Roll sensing===
Tilt switches provide a rollover or tip over warning for applications like construction equipment and lift vehicles that operate in rugged terrain. There are several non-mercury types, but few are implemented due to sensitivity to shock and vibration, causing false tripping. However, devices resistant to shock and vibration do exist.

=== Automotive uses ===
Automobile manufacturers once used mercury switches for lighting controls (for example, trunk lid lights), ride control, and [[anti-lock braking system]]s. Scrapped automobiles can leak mercury to the environment if these switches are not properly removed. Since 2003, new American-built cars no longer use mercury switches.<ref>United States, '' Mercury study report to Congress'',  DIANE Publishing, 1997 {{ISBN|1-4289-0372-0}}, page 2-11</ref><ref>Organisation for Economic Co-operation and Development, ''Instrument mixes for environmental policy '' OECD Publishing, 2007,{{ISBN|92-64-01780-1}}, pg.145</ref>

===Electrification of church bells===
{{cleanup|section|reason=This section does not cite any sources  ([[WP:OR]]?), and may place undue weight on the topic of church bells. 
|date=June 2024}}
In the 1950s, Austrian bellfounder from [[Vienna]], Josef Pfundner jr., decided to develop a new method of electrifying church bells. Austria’s existing electric church bells were already motorized using motors from a German factory in [[Herford]], combined with brakes and gearbox in order to change the direction of the motor, while maintaining an optimal swing angle and changing the swing direction of the bell. This method was expensive, thus, Pfundner decided to use a motor with a brake and ''mercury switch'' instead. This was cheaper, albeit significantly more sensitive. This type of "gearbox" on the yoke contained four mercury switches, specifically, two switches for each direction, which were wired to the motor in such a way as to change swinging direction while the bell was ringing. The bell’s swing angle could be adjusted by carefully moving the switches, though, in an instance where a switch may be incorrectly installed on the yoke, or broken, the bell risked being fatally cracked/damaged.{{Citation needed|date=March 2025}}

Pfundner closed the bellfoundry in 1971. The bellfoundry Grassmayr from Innsbruck in Tyrol had bought a licence for using Pfundner‘s patented method, and they continued to use it for their own bell electrification until the early 2000s. Some church bell electrifiers in [[Croatia]] also adopted this same system (e.g. Alojz Domislovic his successor Luka Ivandija, and later Ivan Bosilj. Ivan Bosilj stopped with usage of mercury switches in 2000). In Vojvodina, [[Serbia]], the same system was used by bell electrifier Mihaly Rozsa, but after his retirement, his systems weren't maintained until end of 2019. Now, one electrician from [[Bečej]] still maintains his work, mercury switches, and motors with brakes by himself.{{Citation needed|date=March 2025}}

===Fall alarms===
Work performed in [[confined space]] (such as a welder inside a tank) raises special safety concerns. Tilt switches sound an alarm if a worker falls over.

===Aircraft attitude indicators/artificial horizons===
Electrically driven attitude indicators typically use mercury switches to keep the gyro axis vertical. When the gyro is off vertical, mercury switches trigger torque motors that move the gyro position back to the correct position. (Air driven attitude indicators use a different operating principle.)

===Thermostats===
Mercury switches were once common in [[bimetal]] [[thermostat]]s. The weight of the movable mercury drop provided some [[hysteresis]] by a degree of [[bistability|over-center action]]. The bimetal spring had to move further to overcome the weight of the mercury, tending to hold it in the open or closed position. The mercury also provided positive on-off switching, and could withstand millions of cycles without contact degradation.

=== Doorbells ===
Some old doorbells, for example, the Soviet ZM-1U4, use mercury switches as current interrupters.

===Pressure switches===
Some [[pressure switch]]es use a [[Bourdon tube]] and a mercury switch. The small force generated by the tube reliably operates the switch.

===Vending and game machines===
Mercury switches are still used in electro-mechanical systems where physical orientation of actuators or rotors is a factor. They are also commonly used in [[vending machine]]s, and used to be common in [[slot machine]]s and [[pinball machine]]s, functioning as a ''tilt alarms'' that detect when someone tries to rock or tilt the machine to make it vend a product or affect a play outcome. They are less common in modern pinball machines due to concerns over mercury toxicity and pinball machines' appeal to children. <ref>{{cite web |last=Rubens |first=Paul |date=17 November 2015 |title=Dancing with the devil: the joy of tilting |url=https://pavlovpinball.com/dancing-with-the-devil-the-joy-of-tilt/ |url-status=live |archive-url=https://web.archive.org/web/20250209090427/https://pavlovpinball.com/dancing-with-the-devil-the-joy-of-tilt/ |archive-date=9 Feb 2025 |access-date=4 May 2025 |website=Pavlov Pinball}}</ref>

===Bombs===
{{Main|Tilt fuze}}
A tilt switch can trigger a bomb.<ref>{{cite news| url=https://www.independent.co.uk/news/people/the-airey-neave-files-661625.html |archive-url=https://ghostarchive.org/archive/20220512/https://www.independent.co.uk/news/people/the-airey-neave-files-661625.html |archive-date=2022-05-12 |url-access=subscription |url-status=live | work=The Independent | location=London | title=The Airey Neave Files | first=Paul | last=Vallely | date=22 February 2002 | access-date=12 May 2010}}</ref><ref>{{cite news| url=http://news.bbc.co.uk/onthisday/hi/dates/stories/march/30/newsid_2783000/2783877.stm | work=BBC News | title=1979: Car bomb kills Airey Neave | date=30 March 1979 | access-date=26 March 2010}}</ref> Mercury tilt switches can be found in some bomb and [[landmine]] [[fuze]]s, typically in the form of [[anti-handling device]]s, for example, a variant of the [[VS-50 mine]].