=

are as shown in the preceding diagram at starting, whilst in B the bobbin has completed one revolution 11⁄2 flyer, therefore the flyer is half a revolution in advance of the bobbin, the rove wound up being half the circumference of the bobbin, or 14 inch. In diagram c the bobbin has returned a second time to the point whence it started, whilst the flyer has completed three revolutions, and bas given out 3 inches of rove, which it has wound around the bobbin, completing its encirclement for the first time. This process is repeated until the whole length of the bobbin intended for the reception of rove is covered by a first layer, the winding of one fold upon another being prevented by the gradual elevation of the bobbin upon the spindle between the legs of the flyer, which brings an uncovered portion of the barrel opposite the eye of the flyer. Throughout this traverse the speeds of the flyer and the bobbin in their relation to one another have been uniform and unchanged.

By the deposit upon the tube or bobbin of the first layer of rove, the surface upon which the winding must now take place has been enlarged. As the diameter of the tube was one inch, it is now one inch plus the diameter of the two plies of rove which a line drawn through the middle of the tube from one outside of the layer of rove to its opposite, would bisect. It is usual to

find the diameter of one ply of rove by carefully measuring the diameter of a full bobbin, subtracting that of the empty one from it, and dividing the difference by the number of layers upon it, which gives the diameter of two plies, there being, as we have seen, two plies in the diameter of each circuit; this divided by two, gives the diameter of each ply. Let us assume that the diameter of the bobbin when empty is 1 inch, and when full 3 inches, the difference will be 2 inches. Suppose the full bobbin to contain twenty-four layers of rove, this number must be used as a divisor of the 2 inches, when the position may be stated thus:

224·0833 ÷ 2 = 04166, the diameter of one ply of rove. As the bobbin or tube, to begin with, is 1 inch in diameter, the first layer will add 0833, the diameter of two plies of the rove, making the result, 1+0833 = 1.0833, the new diameter. The circumference of any circle being 3.1415 times its diameter, the former can always readily be found by using this figure as a multiplier. Every successive layer of rove, therefore, will increase the diameter by the diameter of two plies of the rove, the same as before, and each new diameter multiplied by 3·1415 will give the new winding surface of the bobbin in process of being filled. Paying regard to this principle, we shall find the following to be the result in the case under supposition:

The rove is delivered from the flyer in a cylindrical form, but, when wound upon the bobbin, contact with the barrel and compression by the presser transforms it into an ellipse; the same change also occurs in the rove of each successive layer. This, however, does not affect the calculation when the diameter is obtained as above, because it is taken after the rove has been thus compressed.

The rove is wound helically upon the tube by means of an arrangement called the traverse, which consists in making the bolster rail move upward and downward, sliding the bobbin up and down the spindle at such a rate as to allow the coils of the rove to be laid contiguously to

each other upon the barrel. When the traverse is completed, the movement of the rail is reversed, and at the same moment the speed of the bobbin is accelerated, and a second layer is laid upon the first; the bobbin, if before ascending, now descending, or contrariwise. After the second layer is completed the bobbin again turns back, receiving at the same instant a further acceleration of speed. This takes place at the completion of every layer. With the increasing diameter of the bobbin a fewer number of turns are required to take up the rove delivered. This enables the lift or traverse to be diminished by about the amount of one coil per traverse, and as this diminution takes place at both ends, the effect is that the rove at the extremities of the bobbin is built upon it in the form of cones, the lower one of which is inverted, as will be seen from Fig. 44, in which two bobbins are shown upon the spindles, one being empty, and the other full. It may be necessary to observe that the arrangement here described of the differential motion, and its application to both the speed of the bobbin and the lifting of the traverse rail, necessitates the uniform filling of one" side" of bobbins at `a time, and a similar order of doffing; not permitting, as in the flyer spinning frame, the doffing of one bobbin at a time if it is thought desirable.

The spindles of the slubbing, the intermediate, and the roving frame are constructed alike, and with only slight variations in detail by the different makers. The following Fig. 44, exhibits a detailed view. The spindles, xx, are mounted in the frame as shown, one behind the other, and are driven by the shafts, B B', by means of the bevelled gearing, a a. Ths flyers, 1, are securely mounted upon the spindle tops at x2 so as to partake of their rotatory motion. The flyer consists of a tube, x2, and two hollow legs, xx, to which the pressure fingers, z z, are affixed at z2. The latter turn freely on their bearings at z2, the pressure upon the bobbin being induced by the quick rotation of the spindle and the resistance of the air against

the bobbin. The slubbing, after being delivered by the rollers, is conducted into the tube of the flyer at x2. and comes out of it at o; it then enters one of the tubular legs at z1, from which it emerges at z2, when it is coiled several times round the presser, z, which assists to consolidate it, and then passes through the hole, z3, upon the

Fig. 44. Slubbing Frame. Spindle gearing and bobbin traverse.

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bobbin, y. The bobbins receive their motion from similar shafts, G G', and gearing, e1o e11, to those of the spindles. As the two shafts driving the spindles of the front and back row are actuated by a common driver, they necessarily revolve in opposite directions; in order, therefore, to secure the revolution of both lines of spindles in one way, one row is placed to the left and the other to the right of the driving