180 TRANSACTIONS OF THE 



be regulated at pleasure by the thumb screw at its end. In fig I, 

 the tension is attained by the brake, 31, upon the spool, 30^ which 

 is regulated by the thumb screw, 32. 



The next point of importance is the "feed." Tliis is that part 

 in the operation of the machine, by which the fabric to be sewed 

 is moved forward, and the length of stitch regulated. The length 

 of stitch does not depend at all upon the speed of the machine, 

 but upon the " feed " alone. 



The " feed " consists of a bar, 10, working in grooyes in the 

 front standards, and directly beneath the cloth plate, 46. It has 

 a slot nearly its entire length, in which is pivoted, near the left 

 end, a tongue, 13, with its right end resting upon the right front 

 standards, and armed with two rows of small points, 14. The? 

 relative position of the feed bar and it& appendages to tine cloth 

 plate, is best seen in fig. 6. The cloth plate is furnished with 

 a slot, through which the feed points, when raised, project, and 

 enter the ilibric, held upon the plate by the cloth presser, 20, 

 The feed is worked by the cam;6,which rotates with the arbor, 4. 

 As this cam revolves, the swell of its periphery strikes the under 

 surface of the feed tongue, 13, and raises the feed points, 14, 

 through tlie slot^ 12, while the swell on the right side of the cam, 

 6, presses upon the right ear, 11, of the feed bar, and throws it 

 forward. The cam further revolving brings a point of depression 

 both in its top and its side next to the feed bar ear, when the 

 points drop below the sui-face of the cloth plate, and the feed 

 spring, 12, throws the bar back to the left against the feed stop, 

 54, and the next revolution of the cam throws it forward again. 

 It will be observed, that while the needle penetrates the cloth, 

 the feed points are below the surface of the cloth plate, and 

 intermit their action upon the cloth. Hence the needle consti- 

 tutes a pivot, upon which the fabric may be turned to sew a curved 

 seam of any radius. 



The feed points rising and penetrating the cloth at each stitch, 

 their movement forwai'd determines the length of the stitch, which 

 is graduated by regulating the play of the feed bar. The play of 

 this bar is limited to the diflerence between the widest and the- 

 narrowest parts of the feed cam, 6, which is about one-fom-th of 



