The Mechanical Handling and Storing of Material

ENDLESS ROPE AND CHAIN HAULAGE 247 Fig. 347. Rope Clip or Jockey used in con- nection with Rope Haul- age. incline the trucks are likely to up-end as soon as hooked, and also at the starting and stopping of the rope. The usual method of attaching a truck to the rope of an endless haulage is by means of a “jockey” (see Fig. 347), a V-shaped iron fork fixed to the top of the truck body, into which the rope is forced until the necessary grip is obtained. The form of “jockey” most commonly used in earlier days was bent out of |>-in. round iron into the form of a V with a long arm projecting downwards from one corner to form a means of attachment to the truck. An improvement on the above is the wrought- iron fan-tail “jockey,” made in the shape of a U with the opening slightly tapering towards the bottom, and the jaws are also broadened at the top, so that when the truck receives the pull of the rope and the “jockey” turns slightly in its bracket, the slot holding the rope is partly closed up at the top, owing to the overlie of the fan-shaped jaws, thus locking in the rope and tending to prevent it from rising and pulling out of the “jockey.” A very successful “jockey” is constructed with renewable jaws. Fitted to the top of the pillar is an oblong cast-iron box into which the two jaws are set, these being held in position by means of a wedge driven down between them and through the bottom of the box, this wedge also being held fast by a small wedge and split pin. With this arrangement each jaw can be given a quarter turn when worn, thus allowing the use of four wearing faces before new jaws are required. In laying a haulage track the rail on the side to which the “jockey ” points must be slightly elevated, so that the rope is brought directly over the centre line between the two rails, and to prevent unnecessary wear and tear on the rope, rollers or hard wood rubbing blocks are placed at intervals between the rails to carry the sagging rope. A most important item in the haulage is a properly constructed onsetting point. The grade feeding the trucks to the onsetter should be such that when the truck reaches the rope for hooking, the speed of the rope and truck are exactly the same. Should the speed of the truck be either greater or less than the speed of the rope a sudden jerk will take place on hooking, which is very detrimental to the life of the rope. At a fast feeding onset, brakes should be used to regulate the run in of the trucks, also a contrivance to turn the “jockeys” automatically into the right position for hooking, and as a further safeguard against the trucks leaving the rails at the point of hooking, check rails should be placed for a short distance on each side of the onsetting point. The catenary curve connecting the down grade to the onset with the up grade of the incline requires special attention in laying out, as upon this the rate of hooking largely depends. The rails must follow a line which is parallel to the natural curve taken up by the rope, and to maintain the rope permanently in this position a weight or other tension device is employed. This device, with its frame, also takes up the expansion or con- traction in the rope due to stretch or change of temperature; a well-balanced and sensitive rope is absolutely essential to a fast-feeding haulage. At the point of disengaging the trucks an “ apex ” is formed with a down grade sufficiently steep to cause the truck to overrun the rope, and this change from a pull to a push on the rope causes the “ jockey ” to come square with the rope and easily free itself. On a long steep incline, or, in fact, on any haulage which is at all permanent, automatic disengaging frames should be used in order to dispense with labour. The frames are made in various ways; a cheap and effective one is in the form of a double cross frame carrying two long timber runners (see Fig. 348) placed parallel to the track,