前言我矿矿井提升过卷讯号装置,过去一直采用又大又重的行程开关。由于井下潮湿使接点锈蚀,以致回路时常不通,机械部分经常卡死,不能带动接点断开,因此过卷讯号不可靠。仅一九七二年上半年,我矿运送人员和材料的付井曾先后发生过四次过卷事 Foreword In the past, I used a large and heavy travel switch in mine mine to raise the oversize signaling device. Due to wet downhole corrosion contacts, resulting loop often unreasonable, mechanical parts often stuck, can not drive the contact off, so the signal is not reliable roll. In the first half of 1972 alone, there have been four over-roll events in pay wells for transporting personnel and materials to our mine