To the crank-knob r, [fig. 990.], a rod x, is attached, which moves or traverses the guide bar belonging to that part of the machine; to each machine one such apparatus is fitted. In [figs. 992.] and [993.] another mode of traversing the guide bar is shown, which is generally used for the coarser qualities of silk. Near to one of the middle frames, one of the wheels f, in geer with the spur wheel m, and the bevel wheel n, both revolving on one stud, gives motion also to the wheel o, fixed upon a shaft a′, at whose other end the elliptical wheel b′ is fixed, which drives a second elliptical wheel c′, in such a way that the larger diameter of the one plays in geer with the smaller diameter of the other; the teeth being so cut as to take into each other in all positions. The crank-piece d′ is screwed upon the face of the wheel c′, at such a distance from its centre as may be necessary to give the desired length of traverse motion to the guide bar for laying the silk spirally upon the blocks. The purpose of the elliptical wheel is to modify the simple crank motion, which would wind on more silk at the ends of the bobbins than in their middle, and to effect an equality of winding-on over the whole surface of the blocks. In [fig. 993.] the elliptical wheels are shown in front, to illustrate their mode of operating upon each other. [Fig. 994.] is a block filled by the motion of the eccentric, [fig. 900.]; and [fig. 995.] is a block filled by the elliptical mechanism. As the length of the motions of the bar in the latter construction remains the same during the whole operation, the silk, as it is wound on the blocks, will slide over the edges, and thereby produce the flat ends of the barrel in [fig. 995.] The conical ends of the block ([fig. 994.]) are produced by the continually shortened motions of the guide bar, as the stud approaches, in its sun-and-planet rotation, nearer to the general centre.
[Figs. 996], [997.] are two different views of the differential mechanism described under [fig. 990.]
The bent wire x, [fig. 990.], is called the guider iron. It is attached at one end to the pivot of the sun-and-planet wheel-work t, s, o, and at the other to the guide bar f, f, [fig. 989.] The silk threads pass through the guides, as already explained. By the motion communicated to the guide bar (guider), the diamond pattern is produced, as shown in [fig. 994.]
THE SILK AUTOMATIC REEL.
In this machine, the silk is unwound from the blocks of the throwing-mill, and formed into hanks for the market. The blocks being of a large size, would be productive of much friction, if made to revolve upon skewers thrust through them, and would cause frequent breakage of the silk. They are, therefore, set with their axes upright upon a board, and the silk is drawn from their surface, just as the weft is from a cop in the shuttle. On this account the previous winding-on must be executed in a very regular manner; and preferably as represented in [fig. 994.]
