Doubling

is the next operation of the silk throwster. In this proce , the threads of two or three of the bobbins, filled as above, are wound together in contact upon a single bobbin. An ingenious device is here employed to stop the winding-on the moment that one of these parallel threads happens to break. Instead of the swifts or reels, a creel is here mounted for receiving the bobbins from the former machine, two or three being placed in one line over each other, according as the threads are to be doubled or trebled. Though this machine is in many respects like the engine , it has some additional parts, whereby the bobbins are set at rest, as above mentioned, when one of the doubling threads gets broken. IMG:4147767755307473660_illo1109a.png:Doubling machine Fig. 983. is an end view, from which it will be perceived that the machine is, like the preceding, a double one, with two working sides. IMG:4147767755307473660_illo1109b.png:Doubling machine Fig. 984. is a front view of a considerable portion of the machine. IMG:4147767755307473660_illo1110a.png:Bobbin winder Fig. 985. shows part of a cro section, to explain minutely the mode of winding upon a single bobbin. IMG:4147767755307473660_illo1110b.png:Bobbin winder Fig. 986. is the plan of the parts shown in fig. 985. ; these two figures being drawn to double the scale of figs. 983. and 984. A , A , figs. 983. and 984. are the end frames, connected at their tops by a wooden stretcher, or bar-beam , a , which extends through the whole length of the machine; this bar is shown also in figs. 985. and 986. B , B , are the creels upon each side of the machine, or bobbin bearers, resting upon wooden beams or boards, made fast to the arms or brackets C , about the middle of the frames A . IMG:4147767755307473660_illo1110c.png:Ratchet wheel D , D , are two horizontal iron shafts, which pervade the whole machine, and carry a series of light movable pulleys, called stars , c , c , ( figs. 985 , 986. ) which serve to drive the bobbins E , E , whose fixed pulleys rest upon their peripheries, and are therefore turned simply by friction. These bobbins are screwed by swivel nuts e , e , upon spindles, as in the silk engine. Besides the small friction pulley or bo , d , seen best in fig. 986. , by which they rest upon the star pulleys c , c , a little ratchet wheel f , is attached to the other end of each bobbin. This is also shown by itself at f , in fig. 987. The spindles with their bobbins revolve in two slot-bearings F , F , fig. 986. , screwed to the bar-beam a , which is supported by two or three intermediate upright frames, such as A ′. The slot-bearings F , have also a second slot, in which the spindle with the bobbin is laid at rest, out of contact of the star wheel, while its broken thread is being mended. G is the guide bar (to which the cleaner slit pieces g , g , are attached), for making the thread traverse to the right and the left, for its proper distribution over the surface of the bobbin. The guide bar of the doubling machine is moved with a slower traverse than in the engine; otherwise, in consequence of the different obliquities of the paths, the single threads would be readily broken, h , h , is a pair of smooth rods of iron or bra , placed parallel to each of the two sides of the machine, and made fast to the standards H , H , which are screwed to brackets projecting from the frames A , A ′. Over these rods the silk threads glide, in their pa age to the guide wires g , g , and the bobbins E , E . I , I , is the lever board upon each side of the machine, upon which the slight bra bearings or fulcrums i , i , one for each bobbin in the creel, are made fast. This board bears the balance-lever k , l , with the fullers n , n , n , which act as dexterous fingers, and stop the bobbin from winding-on the instant a thread may chance to break. The levers k , l , swing upon a fine wire axis, which pa es through their props i , i , their arms being shaped rectangularly, as shown at k , k′ , fig. 986. The arm l , being heavier than the arm k , naturally rests upon the ridge bar m , of the lever board I . n , n , n , are three wires, resting at one of their ends upon the axis of the fulcrum i , i , and having each of their other hooked ends suspended by one of the silk threads, as it pa es over the front steel rod h , and under h′ . These faller wires, or stop fingers, are guided truly in their up-and-down motions with the thread, by a cleaner-plate o , having a vertical slit in its middle. Hence, whenever any thread happens to break, in its way to a winding-on bobbin E , the wire n , which hung by its eyelet end to that thread, as it pa ed through between the steel rods in the line of h , h′ , falls upon the lighter arm of the balance lever k , l , weighs down that arm k , consequently jerks up the arm l , which pitches its tip or end into one of the three notches of the ratchet or catch wheel f ( figs. 986. and 987. ), fixed to the end of the bobbin. Thus its motion is instantaneously arrested, till the girl has had leisure to mend the thread, when she again hangs up the faller wire n , and restores the lever k , l , to its horizontal position. If, meanwhile, she took occasion to remove the winding bobbin out of the sunk slot-bearing, where pulley d touches the star wheel c , into the right-hand upper slot of repose, she must now shift it into its slot of rotation. The motions are given to the doubling machine in a very simple way. Upon the end of the framing, represented in fig. 983. , the shafts D , D , bear two spur wheels 1 and 2, which work into each other. To the wheel 1, is attached the bevel wheel 3, driven by another bevel wheel 4 ( fig. 984. ), fixed to a shaft that extends the whole length of the apartment, and serves, therefore, to drive a whole range of machines. The wheel 4 may be put in geer with the shaft, by a clutch and geer-handle, as in the silk engine , and thereby it drives two shafts, by the one transmitting its movement to the other. The traverse motion of the guide bar G , is effected as follows:—Upon one of the shafts D , there is a bevel wheel 5, driving the bevel wheel 6, upon the top of the upright shaft p ( fig. 984. , to the right of the middle); whence the motion is transmitted to the horizontal shaft q , below, by means of the bevel wheels 7 and 8. Upon this shaft q , there is a heart-wheel r , working against a roller which is fixed to the end of the lever s , whose fulcrum is at t , fig. 983. The other end of the lever s , is connected by two rods (shown by dotted lines in fig. 984. ) to a bra piece which joins the arms u ( fig. 984. ), of the guide bars G . To the same cro piece a cord is attached, which goes over a roller v , and suspends a weight w , by means of which the lever s , is pre ed into contact with the heart-wheel r . The fulcrum t , of the lever s , is a shaft which is turned somewhat eccentric, and has a very slow rotatory motion. Thus the guide bar, after each traverse, nece arily winds the silk in variable lines, to the side of the preceding threads. The motion is given to this shaft in the following way. Upon the horizontal shaft q , there is a bevel wheel g ( figs. 983. and 984. ), which drives the wheel 10 upon the shaft x ; on whose upper end, the worm y works in the wheel 11, made fast to the said eccentric shaft t ; round which the lever s , swings or oscillates, causing the guide bars to traverse.