Improvements in or relating to apparatus for recording roof movements, subsidence orthe like in a coal mine or like working

摘要

774,146. Recording deflection of mine-roofs. GULLICK, Ltd., and SEAMAN, T. Dec. 14, 1955 [Dec. 17, 1954], No. 36528/54. Class 106 (2). The apparatus is adapted to be inserted in a boring in a coal face and comprises a segmental platform 15 displaceable by roof convergence to cause pistons 14 to transfer fluid to move a piston 16 bearing a stylus 19 cooperating with a clock-driven recorder 20. The recorder 20 is located in a removable casing 22 forming a coaxial extension of the main cylindrical body 10.