US2160384A - Sewing machine - Google Patents

Description

May 30, 193.9. L KNOTT j 2,160,384

' SEWING MACHINE Filed Jan. 7, 1937 4 Sheets-Sheet l MZ/M May 30, 1939.

4 Sheets-Sheet 2 Filed Jan. '7, 1937 May 30; 1939. C, K TT 2,160,384

SEWING MAQHINE Filed Jan. 7, 1937 4 Sheets-Sheet 3 Wness $067150] May 30, 1939. c KNOTT I 2,160,384

SEWING MACHINE Filed Jan. 7, 1937 4 Sheets-Sheet 4 Vii h. z 1 o 3 j 0 IN 0 0 J 0 Iliiliir- UM Patented May 30, 1939 UNITED STATES PATENT OFFICE SEWING MACHINE Application January 7, 1937, Serial No. 119,444

13 Claims.

The present invention relates to sewing machines, and more particularly to stitch setting devices for lockstitch shoe sewing machines of the McKay type having a straight hook needle and a rotatable shoe supporting horn, similar to the machine disclosed in United States Letters Patent to Topham, Patent No. 2,094,030 dated September 28, 1937.

The usual McKay type shoe sewing machine for commercial work is provided with an elongated angular horn shaped at its tip to enter readily into the toe of a small sized shoe and to support properly the inner surface of the shoe against the thrust of the needle. The sewing thread extends from the work through a needle opening at the tip of the horn and is carried through the length of the horn to a take-up and a tension device beneath the horn. The entire length of thread passing through the horn between the work and the tension device is subjected to the strain imparted by the stitch forming devices in setting a stitch, so that any change in the tendency of the thread to stretch may cause variation to an undesirable extent in the tensions or locations at which interlocking threads of successive stitches are set in the work by the ma.- chine.

The object of the present invention, therefore, is to provide novel and improved means in a McKay type shoe sewing machine, which will contribute to the formation of a uniform seam in the Work operated upon, with successive stitches set more accurately with respect to tension or to location of interlocking threads in the work than heretofore, particularly when sewing at high speeds. Accordingly, a feature of the present invention contemplates the provision in a shoe sewing machine having a straight hook needle and a rotatable shoe supporting horn, of a thread gripping member mounted for movement in the horn towards and from the tip of the horn to impart a stitch setting tension to a relatively short portion of thread extending from the work. By employing a movable gripping member in the horn, the portion of thread subjected to tension can be made much shorter than in previous machines so that the effect of variation in tendency of the thread to stretchwhile setting each stitch is correspondingly decreased. As hereinafter illustrated, the grip-ping member releases the thread when moved in one direction and grips the thread when moved in the other direction.

In the machine of the Topham patent above referred to, the needle looper is arranged to reciprocate towards and from the needle opening face of the looper during movement away from the needle opening to impart the stitch setting tension to the thread.

While the invention is illustrated and described in connection with a lockstitch shoe sewing machine of the McKay type, it is obvious that the principles of the invention are not limited in their application to such machines, but are to be considered as equally useful in other types of sewing machine to the extent indicated in the appended claims.

Other features of the invention will readily be understood from an inspection of the accompanying drawings and the following description of the construction illustrated therein.

In the drawings Fig. l is a View in side elevation, looking from the left of a machine embodying the several features of the invention; Fig. 2 is a view in vertical section on an enlarged scale of the shoe supporting horn employed in the machine, illustrating the mechanism therein; Fig. 3 is a vertical sectional view of the tip of the horn on a further enlarged scale; Fig. 4 is a view in elevation of a portion of the machine beneath the horn, illustrating the arrangement of the takeup; Fig. 5 is a top plan view on an enlarged scale of the needle threading and thread gripping devices provided in the horn of the machine in positions assumed while setting .a stitch; Fig. 6 is a bottom plan View of the same devices in the same positions; Fig. 7 is a top plan view with the needle threading and gripping devices in positions assumed while looping the needle; Fig. 8 is a bottom plan View of the same devices in the same positions; Fig. 9 is a detail side view, partly in section of the needle threading and gripping devices in the positions shown in Fig. 8; Fig. 10 is a somewhat diagrammatic view, illustrating the relation between the work, the needle threading and gripping devices and the take-up just before a stitch is set; and Fig. 11 is a similar view of the parts in positions assumed just after the stitch is set.

Except as hereinafter described, the machine illustrated in the drawings is a lockstitch McKay 50 2 l having a sewing head l2 at its upper end. In the column is rotatably mounted a vertical driving shaft M for rotating the main sewing shaft IS in the sewing head. The sewing shaft [6 is arranged to actuate certain of the stitch forming devices including a reciprocating straight hook :needle l8, a shuttle or loop taker l9 within which .ismounted the usual thread case containing a supply of locking thread. Others of the stitch forming devices are mounted below the sewing head either in a rotatable work supporting horn, indicated at 20 or beneath the horn, and are actuated by suitable connections including a horizontal shaft 22 driven from the shaft I4. I

The stitch forming devices within the horn comprise a reciprocating needle threading looper in the form of a flat rod 24, forkedat its upper end and mounted for movement in the upper end of the horn towards and from a needle receiving opening 26 at the tipof the horn. The looperis provided with a lengthwise passage 28 .(see Figs. ,3 and 9) in one of its forked portions from which the thread passes through the nee- :dle receiving opening 26 to the work. To carry the thread across the forked end of the looper into. a position where "it may conveniently be laid in the needle hook, and to provide a length -of thread for one side of the needle loop as the threadedneedle passes through the work, there .is also mounted in the upper part of the horn a thread finger 30 arranged to swing across the forked end of the looper when the looper is retracted from the needle receiving opening 26. The, looper and threadfinger are driven through suitable connections within the horn from a cam shaft 3|, the rotation of which is imparted from a vertical drive shaft 32 and the shaft 22 in a manner more fully described in the Topham patent. The horn '20 is rotatably mounted in a suitable'bearing 33 in a stationary part of the machine frame and beneath the horn near one end bftheshaft 22 is a take-up 34 of the usual construction (see Fig. 4). The take up is actuated by connections driven from the shaft 22, in the. usual way after each loop ofneedle thread .is disengaged from the loop taker to draw the needle loop and a portionof locking thread surrounded therebytowards the work.

in the machine of the Topham patent, the needle thread, indicated at 36, is drawn from a s pply 31 (See Fig. 1) to a tension 38, a thread lock 40, beneath a pulley 42 in a wax pot 44, over a pulley 45, to the take-up 34. From the takeup, the thread passes upwardly through the length of the horn, past suitably arranged pulleys 4B arrangedto bend the thread into a path corresponding with the angular shape of the horn. Each stitch is set, in the Topham machine, as the needle loop is drawn from the shuttle bythe take-up similar to the take-up 34 in the present application, which acts against the thread look as at 40 in the present application, the lock being applied after an amount of needle thread has been withdrawn from the ,supplyfor the next stitch. To actuatejthe lock 40, a shaft 41 on which the lock is mounted, is ,movedlengthwise by a lever 48 engaging a cam 49 at the forward end of the horizontal shaft 22. In ;the Topham machine the length of needle vthread extendingbetween the lock corresponding to thelock 4D in the present application and the work is such that slight changes in the tendencyof the thread tostretch under a stitch setting tension from one stitch to another may towards the tip of the horn.

downwardly away from the tip of the horn near cause an undesirable variation in the depth to which each needle loop will pull the surrounded locking thread. In order that each needle loop will pull the locking thread engaged thereby to a uniform depth in the work, while a stitch is being set, regardless of the tendency of the needle thread to stretch, in the machine of the present invention, there is provided a thread gripping member mounted in the upper portion of the horn, arranged to move towards and from the tip of the horn close to the needle receiving opening 26. The shape of the cam 49 for actuating the lock 40 is changed from that in the Topham machine to permit the thread to be drawn from the supply while the stitch is being set and to prevent movement of the thread while the take-up is giving up thread.

The thread gripping member, best shown in Figures 8 and 9, is in the form of a flat bar 50 having a wedge shaped thread engaging end slidahly mounted in a channel shaped recess 52 provided in the looper rod 24. The thread engaging end of the gripping member is arranged to enter the thread passage 28 of the looper, and

the passage is tapered to fit wedging surfaces at the thread engaging end of the gripping member. When the gripping member is moved into the thread passage 28 of the looper, one tapering side of the thread passage forces the gripping member against the thread and prevents movement of the thread through the passage. To insure that the gripping memberdisengages the thread when moved out of the passage, at

the central portion of the gripping member is an inclinedslot 54 into which the flattened end of a cylindrical pin 56 projects. The pin 56 is rotatably mounted in the central part of the looper 24 so that the flattened end of the pin may accurately be aligned with the slot 54 in the gripping member.

When the looper 24 begins to move towards the tip of the horn, the gripping bar 50 releases the thread and the thread finger 30, which is in a position illustrated in Figure 5, moves the thread across the forked end of the looper to a position where the thread later may be engaged by the needlecupon further movement of the looper The looper thus forms with the thread finger a bight ofthread, as shown in Fig. '7, suficient for one side of the needle loop as the needle passes through the work. When the threaded needle passes through the work and the needle loop is carried over the shuttle, the thread gripping member 50 still remains disengaged from the thread The take-up then draws the needle loop from the shuttle and a portion of the locking thread, indicated at 58 in Fig. 10, is brought substantially to the surface of the work. Continued movement of the take-up draws thread from the supply and just before the limit of the take-up stroke is reached, the thread gripping member acts. The looper, which at this time is moving the lower end of its reciprocating motion causes the gripping member which is stationary to enter the thread passage 28 of the looper (Fig. 6), so

that it will grip the thread against the tapered side of the thread passage. After gripping the thread, the gripping member moves with the looper to pullthe needle loop to a predetermined depth in the Work, as indicatedin Fig. 11, and apply a stitch settingtension. The endof the 3 pulling moyement of the gripping member is, reached at the lower limit of the take-up stroke,

the portion of needle thread to which the stitch setting tension is imparted being so short that the tendency of the thread to stretch has substantially no effect on the depth at which the stitch is set.

To enable the gripping member to have a limited movement towards and from the tip of the horn while gripping the thread, the gripping member is yieldingly urged towards the tip of the horn. To urge the gripping member in this direction, the lower end is formed with a recess 60 into which a spherically headed pin 62 (see Fig. 2) enters. The pin 62 is mounted at the lower end of an arm 64 fulcrumed on a sleeve 66 and is engaged by a compression spring 68 sup ported in a passage 10 in the frame of the horn. The arm 64 is also provided with a lug 12 cooperating with a surface on the horn to limit the upward movement of the arm. When the looper 24 is actuated towards the needle receiving opening 26, the spring 68 and surface 12 on the arm 64 cause the gripping member to be held stationary, thus releasing the thread. When the looper is retracted from the needle receiving opening, the gripping member remains stationary until moved into gripping relation with the thread and thereafter the gripping member moves the arm 64 under the yielding action of the spring 68 to impart a stitch setting tension to the thread.

An embodiment of the invention having thus been described, what is claimed is:

1. A McKay type shoe sewing machine having, in combination, stitch forming devices including a straight hook needle, a rotatable shoe supporting horn having a needle receiving opening at its tip, and a thread gripping member arranged for movement in the horn towards and from the needle opening to impart a stitch setting tension to the thread.

2. A McKay type shoe sewing machine having, in combination, stitch forming devices including a straight hook needle, a rotatable shoe supporting horn having a needle receiving opening at its tip, and a thread gripping member in the horn actuable to impart a stitch setting tension to the thread when moved in one direction and to release the thread when moved in the other direction.

3. A McKay type shoe sewing machine having, in combination, stitch forming devices including a straight hook needle, a rotatable shoe supporting horn having a needle receiving opening at its tip, a thread engaging member in the horn actuable towards and from the needle opening, and means for causing the thread engaging member to grip the thread when moved away from the needle opening and to release the thread when moved towards the needle opening.

4. A McKay type shoe sewing machine having, in combination, stitch forming devices including a straight hook needle and a looper, a rotatable shoe supporting horn in which the looper is mounted, and means in the horn actuated by the looper for setting each stitch.

5. A McKay type shoe sewing machine having, in combination, a straight hook needle, a rotatable shoe supporting horri having a needle receiving opening at its tip, and a looper mounted for movement towards and from the tip of the horn to lay the thread in the needle hook, and a member for gripping the thread against a surface of the looper during movement away from the horn tip to impart a stitch setting tension to the thread.

6. A McKay type shoe sewing machine having,

in combination, a straight hook needle, a rotatable shoe supporting horn having a needle receiving opening at its tip, a looper mounted for movement towards and from the tip of the horn to lay the thread in the needle hook, a loop taker, a take-up for drawing each loop of thread from the loop taker towards the Work while the looper is moving away from the tip of the horn, and a member in the horn actuated by the movement of the looper away from the horn tip after the take-up has drawn the loop of thread from the loop taker to grip the thread and to set the stitch.

'7. A lockstitch shoe sewing machine of the McKay type having, in combination, a hook needle, a rotatable shoe supporting horn having a needle receiving opening at its tip, a looper mounted for movement towards and from the tip of the horn to lay the thread in the needle hook, a loop taker, a take-up for drawing each needle loop from the loop taker until a portion of locking thread is drawn by the needle loop to the surface of the work, and a member for gripping the needle thread against a surface of the looper during movement away from the horn tip to pull the stitch into the work with a stitch setting tension.

8. A McKay type shoe sewing machine having, in combination, a straight hook needle, a rotatable shoe supporting horn having a needle receiving opening at its tip, a looper mounted for movement towards and from the tip of the horn to lay the thread in the needle hook, a loop taker, a take-up for drawing each loop of thread from the loop taker towards the work while the looper is moving away from the tip of the horn, a thread engaging member cooperating with the looper to set each' stitch, and means for causing said member to grip the thread against a surface of the looper during movement of the looper away from the horn tip and to release the thread while the threaded needle passes through the work.

9. A shoe sewing machine having, in combination, stitch forming devices including a hook needle, a work support having a needle receiving opening, a looper having a passage through which the thread passes to the needle opening in the work support, mechanism for actuating the looper towards and from the needle opening, and a wedge shaped member arranged to enter the thread passage in the looper and to grip the thread against the inner surface of the passage during movement of the looper away from the needle opening.

10. A shoe sewing machine having, in combination, stitch forming devices including a hook needle, a work support having a needle receiving opening, a looper having apassage through which the thread passes to the needle opening in the work support, mechanism for actuating the looper towardsand from the needle opening, a wedge shaped member arranged to enter the thread passage in the looper and to grip the thread against the inner surface of the passage during movement of the looper away from the needle opening, and yielding means for holding the wedge member in gripping relation with the thread for a sufiicient time during movement of the looper away from the needle opening to impart a stitch setting tension to the thread.

11. A McKay type shoe sewing machine having, in combination, a straight hook needle, a rotatable shoe supporting horn having a needle receiving opening at its tip, a looper mounted for movement towards and from the tip of the horn to lay thethread in the needle hook, 'a loop taker, a take-up for drawing each loop of thread from the loop taker towards the work while the looper is moving away from the tip of the horn, and a thread gripping member in the horn movable towards and from the needle opening to apply a stitch setting tension to the thread as the takeup reaches the limit of its thread drawing stroke.

12. A shoe sewing machine having, in combination, stitch forming devices including a; hook needle, a work support having a needle receiving opening, a looper, a take-up, a thread gripping member arranged for movement towards and fro'r'n th'needle opening to impart a stitch setting tension to' the thread and a thread look between the take-up and the thread supply actuated to release the thread while each stitch is being set and to grip the thread while the take up is giving up thread.

13. A McKay type shoe sewing machine having', in combination, stitch forming devices ineluding a straight hook needle, and a looper and. means actuated by the looper for gripping the thread to cause each stitch to be set.

CLYDE L. KNO'I'I.

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