Editing Dead man's switch (section)

====Machinery====
Handle-mounted dead man's switches are also used on many hand-held tools and lawn equipment, typically those that rotate or have blades such as saws, drills, [[snow blower]]s and lawn mowers. On saws for example, they incorporate a squeeze throttle trigger into the handle. If the user loses grip of the saw, the springs in the throttle trigger will push it back out to the off or idle setting, stopping the blade from spinning. Some tools go further and have a trigger guard built into the handle, similar to [[Safety (firearms)|firearm safeties]]. Only when the user presses in the trigger guard first will it then release its lock on the trigger and allow the trigger to be pressed in. Typically, trigger guards can only be pressed in while the user has a firm grip of the handle.{{Citation needed|date=November 2023}}

Every walk-behind mower sold in the US since 1982 has a dead man's switch called an "operator-presence control", which by law must stop the blades within three seconds after the user releases the controls.<ref>{{Cite web |url=http://www.gpo.gov/fdsys/pkg/CFR-2012-title16-vol2/xml/CFR-2012-title16-vol2-part1205.xml |title=SAFETY STANDARD FOR WALK-BEHIND POWER LAWN MOWERS |website=GPO.gov }}</ref> Attached across the handle is a mechanical lever connected by a flexible cable to the kill switch on the engine. While mowing, the operator must always squeeze the lever against the handle. If the operator ever loses grip of the handle, the blade will disengage or the engine will stop, stopping the blades from spinning and (if equipped) any drive wheels from turning.  On mowers where the engine stops, this switch configuration also acts as the engine's main kill switch; when the operator wants to stop the engine, he can release the dead man's switch intentionally.{{Citation needed|date=November 2023}}