These machines are also constructed in various siz, s to suit requirements, and have seversl attachments, not shown in the illustration, such se a regulating drag-gear for delivering the strands at a uniform rate, which is of the greatest importance in securing a well-made rope. The large machines possess in addition a " tempering-motion," the purpose of which is to impart, as may be required, more or less twist to the strands when being laid into ropes. Ropes, according to the nses for which they are intended, require greater or less amount of twist, and this can be exactly regulated by the " hardening " or " softening " process at the time of closing. It is usual, there fore, for every closing-machine to possess a tempering-motion, without which, it would be incomplete. The machine is made so tbat its parts will revolve in either direction, so as to make a rope with either a right- or left-hand twist. In the manufacture of shroud-laid ropes, in addition to the four creels or frames for the strand-bobbins, another is required for the core-piece, which is drawn off at the speed at which the rope is laid. Before coming together, the strands have to pass over a " top," the object of which is to deliver them at exactly the same angle and distance, one from the other. These tops are either of wood or iron, but the former are mostly preferred, because, wood being a better non-conduotor, the heat generated by the frictional passage of the strand snaoothes and polishes it far better than in an iron top, where the heat is dispersed by radiation.
Each machine is capable of making a considerable variety of sizes of ropes, varying in the degree of lay or twist, which is accom plished by altering the speed of the drawing-off motion, by means of change-wheels. Similar means are also provided for varying the drag- and tempeiing-motions, according to requirement.
The various machines, whether vertical or horizontal, required in the processes of stranding and closing are always worked in sets, which generally include t wo stranding- and one closing-machine to a set, though sometimes three of the former and two of the latter are wrought together, forming what is called a double set.
The standard sizes of the machines—at least of those under description—are indicated by letters, and are as follows :— These sizes are based on a length of 120 fathoms iu each coil. Where shorter coils will suffice, each set will produce thicker ropes. Their capacity of production is governed by that of the closing-machine, which can always be ascertained by multiplying the length in in. of the turns or twist in the sample, by the number of revolutions the closing-machine is making a minute, and the product will be the number of in. that will be made in the same time. A percentage, which experience will soon dictate, must bc deducted from this for stoppages, the remainder being a practical result.
The elosing-machines of the different sets make the following revolutions a minute :—E, 130 ; F, 100 ; 70; H, 60 ; I, 50 ; and J, 30.
One man usually superintends a set of machines, taking charge of the closing-machine himself and having assistant boys or girls at the stranding-machines.
The preceding account shows the extent to which the rope-making industry has been revolu tionized by the invention of machinery, in comparatively recent years. But even this does not exhibit the full extent of the changes that have been wrought. The old system of making ropes, as previously described, in long rope-walks by machines working in pairs still survives, and in fact, remains the most widely in use. The machines employed, in what may be termed the more ancient form of rope-making establishments, have also been greatly modified and improved, whilst their general outline and method of operation remain comparatively the same. Having already described the former, a brief account only will be neeessary of the improvements recently introduced.
The "fore-board " has given place to the " foreturn-machine," Fig. 1200, and the " sledge " to the " traveller," Fig. 1201. In the best-furnished rope-walks, as distinguished from rope-fac tories, these machines are now generally fuund. They are used for both the stranding and lay ing processes.
The yarns from which the strands are formed are contained on bobbins placed in the " bob bin-bank " or creel, generally a V-shaped frame with the apex directed towards the rear of the tbreturu-machine, to which the yarn is delivered. These creels may, however, be of different forme, according to convenience or requirement, keeping in view the necessity of maintaining the bobbins in a compact arrangement, and enabling them to be easily accessible for the purposes of renewal when their contents are exhausted, and piecing or splicing when the yarn breaks, or faults occur. As these ereels require to contain 100-400 bobbins, the importance of these considerations will be obvious.
After leaving the creel, the yarns aro conducted through a register-grid—a frame contaieing a number of vertical round-iron rods, traueversely crossed by °there, thus forrning square interstices, each thread having its separate square. This grid is for the purpose of conducting the yarus parallel order to the register-plate—a cast-iron plate drilled with round holes arranged in con eentrie circles, through which the yarns are passed in such a manner as to dispose themselves in passing therefrom in a cempact form round one central thread, which thus forms a core. The diameters of the register-plate cireles are relatively such as to allow the threads in each circle to arrange themselves at the best ascertained angle, in order to compose a solid strand, and receive the general twist necessary to form it. Passing through the register-plate, all the yarns are next eonducted to a strand-tube—a bell-mouthed, slightly tapering, iron tube, which usually passes through a steam-chest, hy which means it is heated, to prevent ropes made of tarred yarns sticking fast, in which case they would have to be cut out, thus occasioning waste, defective work, expense, and inconvenience.