Improvements in Means for Indicating Variations in the Cross-sectional Area of Wire-ropes and similar Magnetic Bodies

97. McCann, C. E. S., and Colson, R. Jan. 1. Gauges ; driving - mechanism for record strips; machines, indicating number and time of working of. -The cross-sectional area of a steel wire rope, such as that employed for mine hoisting-apparatus, is determined electrically by causing the moving rope to form the core of a stationary solenoid through which an alternating or interrupted current is passing. With a constant voltage in circuit, the indications of an armature will be a function of the diameter, and provision is made for recording them on a band, the travel of which is controlled by the motion of the rope. Fig. 1 shows the rope D passing freely through a non- magnetic spool A surrounded by the solenoid windings B ; and to allow of positioning the spool on the rope without threading the end through, it is made in two halves clamped together in a medium plane by set-screws and lugs, but separated by a layer of insulating-material. With this construction, the coil B is also served along the plane and the ends of one part are adapted to fit into tubular sockets attached to the ends of the other part, as shown in Fig. 4. Alternatively, the spool may merely be split down one side ard an insulating layer introduced, in which case the coil is not served, but the rope must be threaded through. Upon the spool are three or more perforated lugs C by means of which the whole may be yieldingly suspended from frames such as B , Fig. 5, by springs, the frames being attached preferably to some rigid framework between the headgear pulley of a mine shaft and the winding-engine. In the arrangement shown in Fig. 1, an ammeter e graduated according to the cross-sectional area of the rope shows the effect on the current due to the changes in self-induction of the coil as thick and thin parts of the rope pass through, a volt-meter e serving to inidicate any variations due to the generator c, but, in the arrangement of Fig. 6, the ammeter and volt-meter H , H' have recording points displaceable laterally upon a record sheet K moved vertically in correspondence with the mine skip and horizontally whenever the winding-engine is reversed, the records being vertical lines for uniform rapes. The paper frame k is moved vertically by means of the two intergeared screw shafts l, l , driven from clock-work L controlled electrically by the skip indicator, and horizontally it is fed from one of the vertical back rollers to the other, passing over two others at the front, one of which h