In view of problem of incorrect operation because that decelerate switch of electric control system of hoist and synchronous switch of backup protection device of hoist all used single tongue tube. a mine-used magnetic proximity switch based on double tongue tubes was designed. Working principle of tongue tube was analyzed. structure. https://safeersappliancers.shop/product-category/rangemaster-lsk90dffss-c-longstock-dual-fuel-cooker-90cm/