. Modern mechanism, exhibiting the latest progress in machines, motors, and the transmission of power, being a supplementary volume to Appletons' cyclopaedia of applied mechanics . es for iiiter-lockiu- the threads and for securing uniform feed and exact tension, and also for produc-ing ornamental stitchings. The newest family machine (Xo. 9) is represented in Fig. is transmitted from the upper to the lower shaft by a crank and sliding connection ; apin at the lower end of the latter, working in a slotted crank arm, gives the necessary vari-able motion to the lower revolving shaft, an
. Modern mechanism, exhibiting the latest progress in machines, motors, and the transmission of power, being a supplementary volume to Appletons' cyclopaedia of applied mechanics . es for iiiter-lockiu- the threads and for securing uniform feed and exact tension, and also for produc-ing ornamental stitchings. The newest family machine (Xo. 9) is represented in Fig. is transmitted from the upper to the lower shaft by a crank and sliding connection ; apin at the lower end of the latter, working in a slotted crank arm, gives the necessary vari-able motion to the lower revolving shaft, and consequently to the rotating hook, thus attord-ing sufficient time for the take-up to draw up the loop of upper thread between the casting-ofl of the loop from the hook and the descent of the needle to form the next stitch. shows the bobbin of under thread in its case, and the tension spring on the latter, iheamount of tension may be regulated when necessary by turning the screw, B but wheiionce properly set the tension is substantially automatic, adapting itself to the differentsizes of thread. Fig. 3 shows the relations of the bobbin and case to the holder and the. I SEWING MACHINES. 791 rotating hook. These parts are brought into proper position by closing the drop, a, whichis firmly held upright by the catch-spring, b. Fig. 4 shows the face-plate of the machine andthe passage of the upper thread through the thread check, tension pullev, thread controller,and take-up, which last is provided with a roller to reduce friction on the thread, and tofacilitate sewing with threads of poor quality. In the •variety stitch machine the loop-taker (or rotary hook) is set with its axis ofrotation at right angles to that of the main lower shaft of the machine ; the needle-bar iscari-ied in a swinging gate connected with a segment lever, which is actuated by a cam on
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Keywords: ., bookcentury1800, bookdecade189, booksubjectmechanicalengineering
