US315742A - Sewing-machine - Google Patents

Description

(No Model.)

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SEWING MAGHINE.

Patented Apr. 14, 1885.

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UNITED STATES PATENT OFFICE.

ELISHA S. CRAM AND EDGAR C. OOVELL, OF LAOONIA, ASSXGNORS OF ONE- HALF TO JOHN S. CRANE AND B. FRANK DRAKE, OF LAKE VILLAGE,

NEW HAMPSHIRE.

SEWiNG-MACHINE.

SPECIFICATION forming part of Letters Patent No. 315,742, dated April 14, 1885.

Application ilcal February 28, 1884i. (No model.)

To @ZZ whom, it may concern:

Be it known that we, ELisHa S. CRAM and EDGAR C. CovELL, of Laconia, in the county of Belknap and State of New Hampshire, have invented an Improvement' in Sewing Machines; and we do hereby declare that the following is a full. and exact description thereof, reference beinghad to the accompanying drawings, making part of this specification.

The purpose of our invention is to enable a sewing-machine to be run backward without the shuttle being allowed to enter the needlethread loop, which, if taken by the shuttle in the backward movement of the machine, will break the needlethread. Sewing-machines generally are so constructed and organized that the shuttle takes the needle-thread loop when the machine is run backward.

By our present invention we effect the purpose by a peculiar construction of the, cani by which the needle-bar is driven with the eccentric or crank pin on the needle-driving shaft, substantially as hereinafter specied.

In the accompanying drawings, Fignrel represents a vertical section through the sewingniachine head and clotlrplate, looking out toward the shuttle and needle, the View showing our improvement; Fig. 2, a similar section of the sewing-machine head in the same plane, but looking in the opposite direction to the View shown in Fig. l; Fig. 3, a face view oi' our improved needle-driving cani, it being shown in full lines, while the usual forni of the cam is indicated by dotted lines in the same ligure.

Like letters designate corresponding parts in all of the figures.

Let A represent the needle of a shuttle sewing-machine; B, the needle-bar; C, the driving-cam on the needle-bar; D, the needledriving shaft; E, the crank-pin or eccentric engaging with the cam on the needle-bar, and G the shuttle.

All the parts of the sewing-machine are or may be constructed as usual, except the cam C on the needle-bar.

The groove of the cani C has two parts, c and b. The part ce, being the forward half, (with a machine organized as that shown in the drawings) is the part in which the crank-pin E asceuds and lifts the. needle-bar to raise the needie when the machine is run forward in sewing; and the part b, being the rear half, is the part in which the crank-pin descends. When the sewing-machine is run backward, however, the crank-pin ascends in the rear part, Z1, and descends in the front part, c, and it is in this backward movement of the machine thatviews in Figs. l and 2 are taken. The forward part, c, of the cam-groove has a rapid upward turn, so that through the first quarter of a circle the crank-pin in ascending therein travels nearly in its own circular pathway coincident therewith, thus not lifting the needle, and thereby giving time for the shuttle to pass through the needlethread loop, and the usual construction of the rear part, b, of the cam-groove is nearly of the same or corresponding shape, or with a similar abrupt rise outward, as indicated by dotted lines in Fig. 3, so that when the machine is turned backward the ascent of the needlebar is correspondingly retarded, thus delaying the raising of the needle till the shuttle enters the needle-thread loop but the timing of the motions of the parts ai'iected is such that the shuttle does not pass entirely through the said thread-loop before the continually-ascending needle pulls np the thread-loop and causes the thread to be broken. Now, our improved construction of the cam is such that in turning the machine backward the raising of the needie-bar and its needle is hastened sufficiently to cause the needlethread loop to be so far raised that the point of the shuttle when it reaches the needle, as shown in Fig. l, cannot enter the said needle-thread loop. We effect this by giving the rear part, b, of the camgroove substantially the form shown in Fig. 1, and by full lines in Fig. 3, it being much more depressed than with the usual construction, and, in fact, extending outward nearly at right angles to the line of motion of the needle-bar. The forni of the groove may vary somewhat, and may be to any extent, provided that it quicken the ascent of the needle as and to the effect herein specified; and our invention is intended to embrace any construction of cam or cam-groove which will effect the result and fulfill the purpose herein set forth. In some sewing-machines the motions are reversed as to the forward and back motions of the driving-shaft D, and the position of the parts of IOO our improv-ed cam-groove are alfeoted thereby, requiring in some machines the front, while in other machines the back of the groove has the special-form given by our invention.

We claim as our invention- 41. The combination, with thestitch-forming mechanismof a sewing-machine having a shuttle adapted to takethe loops of the needle-v thread in the regular motion of the machine, of means, as the crank-pin E and the cam C, constructed With its reverse-motion needleraising part b extended in a direction substantially at right angles to the line'of the needles motion, whereby the needle is caused to carry its thread-loop up away from the shuttle when the motion of the machine is reversed.

2. In a shuttle-sewing machine, the needledriving `cam C, constructed with its rear or reverse-motion needle-raising part b extended in a direction substantially at right angles to the line of the needles motion, in combination with the crank-pin E, needle-bar A, and shuttle G, whereby the needle is caused to carry its thread-loop up out of the Way of the shuttle when the motion of lthe machine is reversed. Y

The above speoication signed by us this 26th day of February, 1884i.

ELISHA S. CRAM. EDGAR C. COVELL. Vitnesses:

FRANK W. REEVES, EDGAR F. REEvEs.

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