Practical wire rope information and useful information on the drag-line cableway excavators . 6 is not a verystrong one and should only be used where the strains are very light. Figure 7 shows a connection made with a loop socket and anopen socket. If the sockets are properly attached this connectionwin develop the full strength of the rope. Figure 8 shows a connection made by bringing the ropesaround thimble sheaves of a strap block and clipping same withthree or more wire rope clips. If the trap block is of proper designand a sufficient number of clips are used, this connection will de-velop
Practical wire rope information and useful information on the drag-line cableway excavators . 6 is not a verystrong one and should only be used where the strains are very light. Figure 7 shows a connection made with a loop socket and anopen socket. If the sockets are properly attached this connectionwin develop the full strength of the rope. Figure 8 shows a connection made by bringing the ropesaround thimble sheaves of a strap block and clipping same withthree or more wire rope clips. If the trap block is of proper designand a sufficient number of clips are used, this connection will de-velop nearly the strength of the rope. The connections shown in Figures 5, 6, 7 and 8 cannot be usedwhere the rope is required to pass over sheaves or drums. Tackle Blocks. Theoretically, the power necessary to balance a load by meansof a tackle consisting of two blocks, is equal to the load dividedby the number of ropes at the moving block, including the standing-part of rope if attached to the moving block. To produce motion,however, a greater power is necessary to overcome the friction and. -28- stiffness of rope. Experiments show that to produce motion aboutlo per cent of the theoretical power must be added for each of thesheaves over which the rope passes. On Plate No. 6 the different tackles are designated by the num-ber of ropes at the moving block. Figure i shows an ordinarysheave block with a rope passing over the sheave. It is very evi-dent that, theoretically, it will require a pull of 15,000 lbs. to balancethe 15,000 lb. load. Figure 2 shows a tackle consisting of twosingle blocks. The rope is attached to the upper block and thenpasses around moving block and up over standing block. This con-stitutes a two part line tackle and, theoretically, the power requiredto balance the load of 15,000 lbs. is 7,500 lbs. or the load divided by2. Iigure 3 shows a three part line tackle. Figure 4 shows a fourpart line tackle, and Figure 5 shows shows a five part line tackle. In using-
Size: 1303px × 1917px
Photo credit: © The Reading Room / Alamy / Afripics
License: Licensed
Model Released: No
Keywords: ., bookcentury1900, bookdecade1910, bookidpracticalwir, bookyear1916
