Should the oil work up and over the top of the bolster, the bobbin and yarn are still quite free from risk of contact, the oil falling down in side the sleeve B, and passing ont beneath the wharve upon the exte,rior surface of the bolster.
By means of the sleeve B and the bush E, the oil is securely protected from contamination by loose fibres, dust, or atmospheric influences. Upon the top of the wharve C, brass cup is securely fixed, for the reception of the foot of the bobbin G, which, however, has its chief bearing at the bushed part near the top of the spindle. The brass cup assists to steady the bobbin, and preserve the balance of the spindle ; but its principal function is to facilitate doffing. Iu removing the full bobbin, the thread between the bobbin and the traveller coils itself in an open spiral upon the sleeve of the spindle. The empty bobbin, being placed upon the spindle, pushes the thread downwards into the cup, where it is firmly held by the contact of the two surfaces. After each operation of doffing, the threads are thus secured without loss of time, simply by the process of supplying the frame with a fresh set of bobbins. The bottom of the bobbin being within the cup, and the thread from the traveller passing over its edge, it is just irr the proper position for recommencing spinning. The bolster is secured in position by means of the nut K. The wire J is fbr tbe purpose of retaining the spindle in the bolster during the doffing operation, or when taking the bobbin off for other reasons.
Another of the most successful ring-frame spindles is represented in Fig. 550. It is known in this country as the Booth-Sawyer spindle. Like the Rabbeth, it is of American origin. In the illustration, 1 represents the outline of the spindle mounted with bobbin; 2 is a vertical section of the same ; 3, the bare spindle. As will be seen from the third sketch, the spindle is very simple, carrying only' the wharve E, and a cup forming an oil chamber K. The bolster has a tube B, which is spirally grooved inside. Its basement is constructed in the form of a tube which receives the oil-cup K on the spindle. The bush 4, composed of bronze, is fitted into the top of the bolster-tube, and constitutes the bear ing. The footstep C is furnished with
an oil chamber F, e,nd a tube extends to the wharve. In the bolster, lubri cation is effected at M, when the oil poured into the cup flows through the hole into the bolster-tube, until it meets the revolving spindle, which carries it along the spiral groove to the bronze bush, where it comes into contact with the bearing surfaces between which it is forced by the pressure of the stream ascending from below. As this is con stantly going on, the oil would be liable to pass over the top, flow away, and be wasted ; but against this, provision is made by vertical grooves being cut into the sides of the bush, ss seen at 4, and in the section of this at 5, the bush being inserted a little below the top of the holster-tube, the oil which overflows passes down the vertical groove P in the bush, and at 0 re-enters the bolster tube, there to be used over again. This is continuous, so that the spindle is kept perfectly lubricated, and no oil is wasted. When the spindle is at rest, the oil flows down the spiral groove into the spindle cup K, where it remains until work is resumed. Both oil chambers are supplied with covers, to prevent the entrance of loose fihre, dust, &c. Experience has proved this to be an efficient and economical method of lubricating the spindle, which, owing to the high speeds attained, is an absolute neces sity if the machine is to be preserved for any length of time in working order. The bobbin for the Booth-Sawyer spindle is designed to secure lightness, firmness, and steadiness on the spindle. It possesses a wide bore, which extends almost to the top, where it is reduced so as to fit the spindle point only. In the centre of its length, it is bushed, at which point the second bearing is foimed. Thus being firmly held at two points upon the taper spindle, it iB quite free from vibration.
There is a tendency in the " traveller " to collect fibre upon itself, which seriously injures the quality of the yarn, by increasing the strain upon it beyond the point it is calculated to bear. Many ingenious attempts have been made to overcome this difficulty, and several plans now in use Are more or less efficient.