US2075537A - Sewing machine - Google Patents

Description

March 30, 1937. D c MQRELAND 2,075,537 Q SEWING MACHINE 2 Shets-Sheet 1 Filed Jar 1. 8, 1935 i J JJMKW/ZZ March 30, 1937. D. c. MORELAND 2,075,537

SEWING MACHINE Filed Jan. 8, 1955 2 Sheets-Sheet 2 A. 0 4% in, I/

Patented Mar. 30, 1937 UNITED STATES PATENT OFFIE SEWING MACHINE Application January 8, 1935, Serial No. 867

2 Claims.

This invention relates to sewing machines, and while in some aspects not limited thereto, is of special utility in connection with machines for sewing on buttons or the like.

5 The Lyons Patent No. 1,915,831 granted June 27, 1933, discloses a machine for sewing on buttons in which provision is made, for a purpose fully set forth in that patent, to pull back the cast off loops of threads in two stages with an '10 intermediate dwell. One of the objects of the present invention is to provide a simplified mechanism for accomplishing the same result and which eliminates certain threading operations required by the patented construction.

The construction of the present invention also provides for easy adjustment of the amount of pull back in the initial pulling operation and the duration of the dwell.

For a more complete understanding of this invention, reference may be had to the accompanying drawings in which Figure 1 is a side elevation of a two-needle button sewing machine constructed in accordance with this invention.

Figure 2 is a front elevation of the sewing head showing the needles fully retracted.

Figures 3 to 6 inclusive are somewhat diagrammatic views showing successive positions of the needle bar and needle and corresponding positions of the looper mechanism.

Referring first to Figure 1, at l is indicated a suitable support, such as a table top, on which is pivoted as on the cotter pins 2, a sewing machine base 3. This base 3 is provided with spaced lugs 4 which cooperate with lugs 5 secured to the upper face of the support I and receive therethrough the pivot cotter pins 2. The machine base 3 is provided with the usual upstanding sewing arm i at one end which extends over the base toward the front of the machine and has on its forward end the sewing head 8. The sewing head has reciprocably mounted therein a needle bar 9 which may be reciprocated by any suitable means such as the crank l carried by a rotary shaft II, the crank being connected through a link I 2 to an element 13 secured to the needle bar. The shaft ll extends through the sewing arm in the usual manner and is shown as connected through a crank l and a connecting rod IS with a crank I! on a main drive shaft I8 mounted in the base 3. The shaft 18 is provided with a cam l9- at its forward end having suitable cam paths such as 20 and 2| for control of the various thread handling mechanisms, such as the usual thread finger which cooperates with suitable loop takers such as 22. As shown there are two of these loop takers in the form of oscillatory loopers which may be driven from the main drive shaft i8 as shown in the Lyons Patent No. 1,915,831 in suitable timed relation to the strokes of the needle bar 9. Cooperating with these loop takers are the two needles 25, both of which are secured to the lower end of the needle bar 9. The various sewing instrumentalities and work handling devices cooperating therewith may be identical with those shown in this Lyons patent.

To the top of the sewing arm 1 is seemed a bar 39 which extends over a pair of thread stands 28, one on each side of the arm 1 and has the thread guide openings therein from which the threads from the stands are led and from which both are passed to the automatic tension 35, which is actuated at suitable times in the cycle of operation to grasp or release the thread in the manner disclosed in the Lyons patent. From the tension 35 both threads are led through a thread guide 36, and thence to a permanent ten sion 31. After passing this tension 37 they are directed through a thread guide at 38 and then through thread guide holes 39 through the needle bar 9 in a portion thereof extending above the sewing head 8. From this needle bar they pass down over the front face of the sewing head to the tension 40 and from this tension 43 they pass to the eyes of the needles 25.

Between the tension 40 and the needle bar thread guides 39 and adjustably secured to the front face of the head 8 is positioned a member 42 with which the threads may engage at suitable times in the stitching cycle for a purpose which will later be described. As shown in Figures 2 to 6, this member 42 consists of a bar portion 43, which as best shown in Figure 1, has a rounded top face 44, this bar having a shank portion 45 which may engage in a shallow channel 46 in the front face of the head 8 and be adjustably secured therein as by a screw 41 passing through a slot 48 in the shank portion and threaded into the forward face of the head 8. The member 42 is so adjusted that as the needle bar 9 approaches the limit of its downward or sewing stroke, as shown in dotted lines in Figure 1, the thread guides 39 are brought below the upper face of the bar portion '43, increasing the length of the path through which the thread passes from the bar guides 39 to the thread tension 40 and thus to the needles 25. Also the needle bar thread guides 39 when approaching the limit of the down motion of the needle bar pass beyond a straight line between the guide portion 38, where the thread emerges, and the top 44 of the bar portion 43, thus to lengthen the thread path between the guide 38 and the bar 43 as shown in dotted lines in Figure 1.

These two actions result in the thread being pulled back through the tension 48, which is looser than the tension 37, as the needle approaches its lower limit of sewing stroke, this pull back being succeeded by a dwell as the needle bar starts to retract and until the guides 39' are as much above the straight line position between the guide 38 and the top of the bar 43 as they were previously below this straight line position on the downward or sewing stroke of the needle. Further upward motion of the needle bar 9 then continues the drawing back of the thread until the needle bar reaches its highest position shown in Figures 1 and 5.

Referring to Figures 3 to 6, it will be noted that when the needle bar is descending so that the thread just begins to bear over the bar member 43, the needles 25, one of which only is shown in these figures because the two needles are in front to rear alinement, are near the lower ends of their strokes and the hook at of each looper projects through the loop of thread previously taken down by its needle and which has been opened for the passage of the needle by the action of the thread finger 5i. As the needle bar descends further toward the position of Figure 4, the looper hooks 50 retract, casting ofi" the previously opened loops onto the needles and over the loops of thread then in the needle eyes, the cast off loops being then drawn loosely back around the needles, but out of the way of the looper hooks, so that on their next forward passage, as shown in Figure 6, to take the succeeding loops from the needles, they do not engage the cast ofi loops.

On the further retraction of the needle bar to its full retracted position shown in Figure 5, the cast off loops are pulled up tight against the work, leaving the loops just taken from the needles on the looper hooks 5i) ready for a succeeding down stroke of the needles to the position shown in Figure 3. It will be noted that the use of the member 42 does not require any additional threading of the threads between the needle bar and the tension 40 and that by vertical adjustment of the member 42, the amount of the initial pull back of the threads to escape the hooks and to partly tighten the cast off loops about the needles may be adjusted to suit the particular conditions at any time. For the greater portion of the stroke of the needle bar, the threads bear very lightly on the member 42 so that it does not produce appreciable wear thereon, nor is it itself subject to rapid wear from the threads passing thereover.

From the foregoing description of an embodiment of this invention, it should be evident to those skilled in the art that various changes and modifications might be made without departing from the spirit or scope of this invention as defined by the appended claims.

I claim:

1. In combination in a sewing machine, an arm, a sewing head at the forward end of said arm, a needle bar reciprocable in said head, a needle carried by said bar, a thread guide on said bar, a thread tension on said head between said bar guide and said needle, and a member with which the thread may engage carried by said head between said tension and bar guide and acting on the last portion of the sewing stroke of said needle to effect an increased length of thread path between said tension and bar guide.

2. In combination in a sewing machine, an arm, a sewing head at the forward end of said arm, a needle bar reciprocable in said head, a needle carried by said bar, a thread guide on said bar, a thread tension on said head between said bar guide and said needle, a member with which the thread may engage carried by said head between said tension and bar guide and acting on the last portion of the sewing stroke of said needle to effect an increased length of thread path between said tension and bar guide, and means facilitating adjustment of the position of said member to thereby determine the amount of such increase.

DANIEL C. MORELAND.

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