SILK MANUFACTURE 



797 



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 gear 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 d, 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 



1788 



of the blocks. In fig. 1785, the elliptical wheels are shown in front, to illustrate 



their mode of operating upon each other. 



Fig* 1786, is a block filled by the motion of the excentric, fig. 1782 ; and fig. 1787, 



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. 1786. 

 The conical ends of the block (fig. 1787) are pro- 

 duced 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. 1788 and 1789 are two different views of the 

 differential mechanism described under fig. 1782. 



1789 



ff 



The bent wire x, fig. 1782, is called the guide-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. 1781. 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. 1786. 



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 exe- 

 cuted in a very regular manner, and preferably as represented in fig. 1786. 



Fig. 1790, is a front view of the reel ; little more than one-half of it being shown. 



Fig. 1791, is an end view. Here the steam-pulleys are omitted, for fear of obstruct- 

 ing the view of the more essential parts. A, A, are the two end framings, connected 

 by mahogany stretchers, which form the table B, for receiving the bobbins c, c, which 

 are sometimes weighted at top with a lump of lead to prevent their tumbling. D is 

 the reel, consisting of four long laths of wood, which are fixed upon iron frames, 

 attached to an octagonal wooden shaft. The arm which sustains one of these laths is 

 capable of being bent inwards by loosening a tightening hook, so as to permit the 

 hanks, when finished, to be taken off, as in every common reel. 



The machine consists of two equal parts coupled together at a, to facilitate the 

 removal of the silk from either half of the reel ; the attendant first lifting the one part 

 and then the other. E, is the guide-bar, which by a traverse motion causes the silk 



