US2159166A

US2159166A - Lock stitch shoe sewing machine

Info

Publication number: US2159166A
Application number: US96005A
Authority: US
Inventors: Clyde L Knott
Original assignee: United Shoe Machinery Corp
Current assignee: United Shoe Machinery Corp
Priority date: 1936-08-14
Filing date: 1936-08-14
Publication date: 1939-05-23
Anticipated expiration: 1956-05-23
Also published as: DE708650C; FR825403A; GB498044A

Description

May 23, 1939. c. L. KNOTT LOCK STITCH SHOE SEWING MACHINE Filed Aug. 14, 1936 15 Sheets-Sheet l May. 23, 1939. c. L. KNOTT LOCK STITCH SHOE SEWING MACHINE Filed Aug. 14, 1936 15 Sheets-Sheet 2 May 23, 1939 c. KNOTT 2,159,166 LOCK STITCH SHOE SEWING MACHINE Filed Aug. 14, 1936 15 Sheets-Sheet 3 W y 1939- c. L. KNOTT I 2,159,166

OCK STITCH SHOE SEWING MACHINE Filed Aug. 14, 1936 15 Sheets-Sheet 4 q/mr 1 4 y 1939- c. L. KNOTT 2,159,166

LOCK STITCH SHOE SEWING MACHINE Filed Aug. 14, 1936 15 Sheets-Sheet 5 I May 23, 1939. c. L. KNOTT 2,159,166

LOCK STITCH SHOE SEWING MACHINE Filed Aug. 14, 1936 15 Sheets-Sheet 6 May 23, 1939.

Wiiness 79 6 WW @w C. L. KNOTT LOCK STITCH SHOE SEWING MACHINE Filed Aug. 14, 1936 15 Sheets-Sheet 7 LOCK STITCH SHOE SEWING MACHINE Filed Aug. 14, 1936 15 Sheets-Sheet 8 .MIMM

y 23, 1939 v I c. L. KNOTT 2,159,166

LOCK STITCH SHOE SEWING MACHINE Filed Aug. 14, 1936 15 Sheets-Sheet 9 Witness #cmQTM May 23, 1939.

C. L. KNOTT LOCK STITCH SHOE SEWINE MACHINE Filed- Aug. 14, 1936 15 Sheets-Sheet l0 May 23, 1939. c. 1.. KNOTT 2,159,166

LOCK STITCH SHOE SEWING MACHINE Filed Aug. 14, 1936 1 15 Sheets-sheaf. 11

May 23, 1939.

C. L. KNOTT LOCK STITCH SHOE SEWING MACHINE Filed Aug. 14, 1936 15 Sheets-Sheet 12 May 23, 1939. c. L. KNOTT LOCK STITCH SHOE SEWING MACHINE Filed Aug. 14, 1936 15 Sheets-Sheet l5 May 23, 1939. c. L. KNOTT LOCK STITCH SHOE SEWING MACHINE Filed Aug. 14, 1936 15 Sheets-Sheet l4 y 1939. c. 1.. l (NOTT 2,159,166 v LOCK STITCH SHOE SEWING MACHINE Filed Aug. 14, 1936 15 Sheets-Sheet l5 Wflness 164 6. Via

Patented May 23, 1939 PATENT OFFICE LOCK STITCH SHOE SEWING MACHINE Clyde L. Knott, Beverly,

Mass, assignor to United Shoe Machinery Corporation, Paterson, N. J., a corporation of New Jersey Application August 14, 1936, Serial No. 96.005

58 Claims.

The present invention relates to improvements in shoe sewing machines of the McKay type which employ a straight hook needle and a rotatable shoe supporting horn, and is intended more particularly as an improvement in a shoe sewing machine similar to that illustrated and described in U. S. Letters Patent No. 2,094,030 of Laurence E. Topham dated September 28, 1937, the rotatable horn of which is provided with a thread finger for measuring a length of thread between the work and the needle during each stitching cycle to insure that the threaded needle pass easily through the work without causing the thread to slide through the needle hook. However, certain features of the invention are of more general application and may be employed to advantage in sewing machines other than those of the straight needle or McKay types.

The objects of the invention are generally to simplify the construction and improve the mode of operation of McKay type shoe sewing machines so that sewing may beeifected more uniformly and with greater reliability at high speeds than heretofore. In order to sew close to the inner surfaces of the upper in shoes having small pointed toes, it is necessary to use a horn of as small outside dimensions as possible. A more definite object of the invention, therefore, is to provide a McKay type shoe sewing machine having a needle looper and thread finger so arranged as to op rate effectively within the confines of the rotatable shoe supporting horn, the tip portion of which compares in size with or is even smaller than that of previous machines without a thread finger.

With these objects in view, an important feature of the present invention contemplates the provision in a McKay type shoe sewing machine having a rotatable shoe supporting horn and a thread finger in the horn, of a needle looper movable between looping position at the tip of the horn and the thread finger to carry the thread about the thr ad finger before the needle is looped. In the illustrated embodiment of this feature of the invention, the looper is given a movement towards and from the horn tip, and the thread is engaged with the thread finger at one end of the movement of the looper and is laid in the needle hook at the other end of the movement. To accomplish this result, as hereinafter described, the looper is rotated at each end of its movement towards and from the horn tip, about an axis extending in the direction of the movement, first in one direction to carry the thread about the thread finger, and then in the other direction to lay the thread in the needle hook. By this construction a looper of extremely small dimensions at its thread engaging portion may be employed while the advantages of mounting the thread finger at a distance from the horn tip, as in the machine of the Topham patent are retained.

The above mentioned feature of the invention is embodied in a McKay type sewing machine, the horn of which has a looper actuating mechanism comprising a single crank driven member so connected that the component motions of rotation in different directions impart, respectively, the rotating movement to the looper and the movement towards and from the tip of the horn. In the illustrated form of this feature of the invention, two separate trains of connections be tween the looper and the crank driven member are provided, one for each movement.

To shorten the length of thread operated upon by the take-up, in certain previous McKay type sewing machines, the take-up is mounted as close as possible to the work, directly on the rotating horn. To operate the take-up, reciprocating connections are provided extending between the horn and the stationary frame of the machine. The weight of these connections so increases the vibration and wear that proper operation is diflicult, if not impossible, at the high speeds desired in present stitching practice. Accordingly, in the machine of the present invention, a continuously rotating drive shaft is provided in the horn so that the connections between the take-up and the drive shaft may be shortened and simplified. To insure exactly the correct relation of timing in the movements of the take-up and the looper, the take-up actuating shaft also carries the looper actuating member.

In McKay type shoe sewing machines in which there is a thread measuring finger mounted in the horn, it has heretofore been impossible to form a seam with uniform stitches throughout its length due to difiiculty in looping the needle always in the same relation as the horn is retated. The presence of a thread finger in the horn prevents the thread from being effectively laid in the hook of the needle until the thread extending from the thread finger is wound about the needle through an angle great enough to draw the thread into the open needle hook. Since the position of the thread finger is changed with the rotation of the horn, the angle through which the looper must wind the thread about the needle is changed correspondingly. After the threaded needle is withdrawn from the work, the sides of the loop supported by the needle will be twisted about each other to an extent equal to the angle through which the horn is rotated and in certain positions of the horn a 180 degree or even greater twist in the needle loop will result. A stitch formed with a needle loop thus twisted will, be irregular and will not be pulled into the work securely. A feature of the present invention, therefore, contemplates the provision of mechanism in a McKay type sewing machine for turning the needle about its lengthwise axis, such that after being looped the needle is turned in the proper direction to prevent stitches being formed with threads twisted regardless of the angular position of the horn. As herein disclosed, this feature of the invention consists in mechanism for turning the needle in one direction when the horn occupies a position with the thread finger at one side of the line of feed, and in thev reverse direction with the thread finger at the other side of the line of feed. With this arrangement, when the needle hook is in a. neutral position facing in the line of feed, no turning movement is imparted since no twisting of the loop takes place.

According to another feature of the invention, there is provided a novel, improved and simplified mechanism for turning the needle which, while well adapted for turning the needle in the manner just indicated, is not limited to operation in the exact manner referred to, but is useful in turning the needle of a straight needle sewing machine forother purposes and in other relations to the horn or to other parts of the machine during each sewing cycle. As herein illustrated and described, the needle turning mechanism comprises a cam connected to the horn having a surface of gradual pitch with an abruptly inclined portion between the extreme high and low points of the surface and, in order to prevent the cam follower cooperating with the cam from affecting free rotation of the horn, the follower is raised from the cam surface during each stitching cycle to clear the abrupt portion. The operator, therefore, may swing the horn without any perceptible resistance through the angle including this abrupt portion, while the follower moves first from the low point and then to the high point of the cam surface.

In addition to the features above referred to, other features of the invention relate to a loop spreader of improved construction and operation, a novel and improved presser foot arranged to increase the visibility at the point of operation of the stitch forming devices on the work, and the devices, combinations and arrangements of parts hereinafter described and'claimed.

The several features of thepresent invention and the advantages obtained thereby will be readily understood by those skilled'in the art from the following description taken in connection with the accompanying drawings which illustrate an embodiment of the invention.

In the drawings Fig. 1 is a view in side elevation of a complete machine embodying the features of the present invention; Fig. 2 is a view in side elevation, on an enlargedscale, of the sewing head of the machine, looking from the left; Fig. 3 is a view in front elevation of the sewing head; Fig. 4 is a view in side elevation of a portion of the sewing head on a slightly larger scale, looking from the right; Fig; 5 is a view'inright side elevation,

and partly in section of the loop spreader and a portion of its actuating mechanism; Fig. 6 is a plan view of the loop spreaden'indicating its path of movement; Fig. 7 is a perspective view of a portion of the needle turning mechanism; Fig. 8 is a view in right side elevation partly in section on a further enlarged scale of a portion of the needle turning mechanism of the machine; Fig. 9 is a detail view in elevation on a still further enlarged scale of 'a part of the mechanism shown in Fig. 8, looking from the opposite side of the machine; Fig. 10 is a sectional plan view taken along the line l0--I0 of Fig. 9; Fig. 11 is a view illustrating the relation of the needle and presser-foot on the work as seen from the front of the machine; Fig. 12 is a sectional view, taken along the line l2l2 of Fig. 11; Fig. 13 is a view of the presser-foot and needle in operating relation with the work, looking from the right; Fig, 14 is a view in front elevation, partly in section, showing the main needle thread tension and supply, of the machine shown in Fig. 1; Fig.15 is a detail view of the needle thread tension and its operating mechanism on an enlarged scale; Fig. 16 is a view in vertical section on an enlarged scale of the shoe supporting horn illustrating the mechanism therein; Fig. 17 is a view on a still larger scale of the tip portion of the horn indicating the position of the parts just after the needle thread is carried about the thread finger; Fig. 18 is a sectional view of the horn on a further enlarged scale, taken along the line l8-|8 of Fig. 16; Fig. 19 is a similar view taken along the line I9I9 of Fig. '16; Fig. 20 is a detail view of a portion of the looper and thread finger actuating connections shown partly in section as viewed along the line 20-20 of Fig. 16; Fig. 21 is a detail sectional view of a thread ten: sion device, taken along the line 21-21 of Fig, 16 Fig. 22 is a detail view of a portion of the looper actuating connections as seen from the line 22 22 of. Fig. 16; Fig. 23 is a partial sectional view of the parts at the lower portion of the horn; Fig. 24 is a. view of the horn tip similar to Fig. 17 with the parts shown in positions just as the needle is being looped;Fig. 25 is a view of thetake-up and its actuating mechanism; Fig. 26 is a view of a portion of the looper actuating mechanism; Fig. 27 is a view of a portion of the thread finger actuating mechanism; Fig. 28 is a sectional view of the pitman and connections for actuating the looper, taken along the line 28-28 of Fig. 26; Fig

29 is a detail view of the looper and thread finger actuating crank shaft; Fig. 30 is a detail view illustrating the positions of the needle just before the needle loop is spread, and just before the loop is lifted from the needle hook, respectively; Figs. 31 and 32 are sectional views of portions of a seam illustrating irregular forms of stitches; Figs. 33 and 34 are detail plan views illustrating the relative positions of the thread and the needle when the horn is rotated; Figs. 35 and 36 are detail views in elevation illustrating the relation of the looper and thread while the needle is'being looped and while the horn is in the positions shown in Figs. 33 and 34, respectively; Figs. 3'7 and 38 are detail views in elevation, illustrating the manner of untwisting the needle loop while,

the needle moves upwardly; Figs; 39 to 44 inclusive are detail views illustrating successive positions of certain of the stitch forming devices during a complete cycle of operation of the machine; and Fig. 45 is a further detail view indicating the path taken by the thread Within the horn while the needle loop is passing over the shuttle.

patents to Ashworth No. 1,914,936 dated. June 20, 1933, and to Leveque No. 1,885,927 dated November l, 1932. Many of the parts and mechanisms of the machine herein disclosed as embodying the several features of the present invention are the same as those described more in detail in the above mentioned application and patents, and therefore will be referred. to only briefly in the following description.

The illustrated machine is driven from an electrical motor 2 through a clutch mechanism 4 controlled from a foot treadle 6 which is normally held in raised position by means of a spring 8. The clutch mechanism acts to connect and disconnect the motor with the shaft H3 and with a sleeve l2 in the base of the machine, from which shaft or sleeve motion is transmitted to a vertical shaft l4 extending upwardly to the sowing head of the machine. Rotation of the shaft M imparts a corresponding rotation to the main sewing shaft It for operating the needle, shuttle and other related parts.

The rotary horn of the machine, indicated at I8, is of the usual shape common. to this type of machine, and is provided with an inclined. upper portion enclosing the needle threading devices. To actuate the needle threading devices, the shaft M is connected through suitable gears to a horizontal shaft 29 and a hollow vertical shaft 22 mounted for rotation concentrically with the rotary axis of the horn is similarly connected to the shaft 28. The vertical shaft 22 extends from its hearings in the frame of the machine upwardly into the horn where it acts to drive a continuously rotating horizontal shaft 2 from the rotation of which suitable movements are imparted to the needle threading and other devices acting on the needle thread.

The stitch forming devices in the sewing h ad of the machine, best shown in 2, 3, and 4:, include, in addition to the straight hook needle indicated at 26, a presser-foot 28, a loop taker in the form of a shuttle 35, a bobbin thread case 32 about which the shuttle carries the needle thread, a feed point 34 and a loop spreader 35. The needle 26 is clamped in a needle holder St at the lower end of a needle bar dil mounted in bearings 42 and M on the frame of the machine. Between the bearings 42 and M on the needle bar is clamped a block d surrounding which t v, is an open frame til loosely supported on he needle bar and connected by means of link t" with a needle actuating lever 52 secured to the forward end of a rock shaft 54. Loosely mounted on the rock shaft 54 near its forward end is a lever 56, the central part of which. carries a cam roll 58 engaging a cam 69 secured to the forward end of the main sewing shaft it. During sewing operations, the cam actuated lever is connected to the needle actuating lever 52 and at the end of the sewing operations, the two levers are disconnected by connections including a latch 62 pivotally mounted on the lever 52 and arranged with its hook shaped lower end to engage a pin 5d at the end of the lever 55. At its upper end, the latch 52 cooperates with the upper end of a locking lever 56 secured at its lower end to a shaft 68 and. arranged when the shaft is rocked in a clockwise direction to permit the levers to be connected, and when rocked in a reverse direction to disconnect the levers. On rearward end of the shaft 58 is mounted an arm 69 connected to a lever l6 rotating on a shaft H and having an arm engaging a lug on an arm 72 secured to the shaft ll, the arm 72 being actuated througl a rod 13 connected to the foot treadle 6. Between the lever 18 and shaft ll there is a spring 6'! (see Fig. 3) acting when the treadle is depressed to yieldingly actuate the locking lever 55 and to connect the two

levers

52 and 56, as more fully illustrated and described in the Ashworth and Leveque patents above referred to.

The presser foot 28 is secured to the lower end of a vertically movable presser-foot bar it which is forced downwardly against the work by suit able springs and is raised by mechanism including a pin '15 extending from an arm i6 secured to a cam actuated shaft 7! and other devices attached to a bracket '58 slidable on the presserfoot bar for causing the pin 75 to raise the presser-foot a uniform amount regardless of the thickness of the work during each stitch forming cycle.

The feed point 3 3 is clamped in a carrier 19 slidably mounted for vertical movement towards and from the work in a guide frame 89 which is pivotally mounted on the machine frame. To raise and lower the feed point from the work, the upper end of the feed point carrier is connected by a link 82 with a bell crank 84. The bell crank 84 is connected through a link 85 with an arm 87 also secured to the shaft 1'? so that the feed point will engage the work when the work is released from the pressure of the presser-foot.

The rotary horn i8 is provided at its lower end with a hollow spindle 83 (see Figs. 8 and of the usual form supported in suitable bearings on which the horn may be rotated without limitation in either direction in the machine frame. At the upper end of the born there is provided a needle opening 96, the center of which coincides with the axis of rotation of the spindle 63. As in the machine of the Topham patent, the upper end of the horn in the present machine is provided with a hook shaped thread finger 92, hereinafter more fully described, mounted with its thread engaging portion at a distance from the horn tip for holding a bight of thread at one side of the needle opening. The needle looper of the Topham machine is given a simple reciproeating movement towards and from the tip of the horn and is forked at its upper end to surround the needle in layin the thread the needle hook. In that machine, the thread finger actuated across the path of thread extending from the work to measure a length sufficient to insure that the thread will not slide through the heck of the n edle as the threaded needle through the material of the work. In addition to the thread measuring movement of the thread finger in the Topham machine, the is also actuated at right angles to its measuring movement to release the thread the threaded needle passes through the work.

An important feature of the present invention consists in so arranging the needle looper and thread finger in the tip of the born that the measurement and engagement of the thread with the thread finger are accomplished entirely by the operation of the looper, the only movement given the thread finger being to release the measured thread at the proper time. The looper, as indicated at 94 in Figs. 16 to 19 inclusive, and 24 consists of an elongated hollow rod slidably and rotatably mounted within a hearing or guideway 95 formed in the inclined upper part of the horn.

1e bearing 95 extends parallel to the upper part of the horn so that the center line of the bearing intersects the longitudinal axis of the needle and the coincident rotary axis of the horn at an acute angle. The upper thread engaging end of the thread all) needle looper is formed with an eccentrically arranged thread guiding eye 98into which the thread is carried after passing through the looper. The edge of the looper opposite the eye 98is bevelled to provide a surface forming an angle withthe center line of the guideway 96 such that when the looper is in its uppermost position, the thread will lie substantially parallel to the work engaging surface of the horn. When the looper is in this position, the needle is surrounded by the hollow end of the looper which is provided with a recess 99 of suflicient size to clear the point of the needle. As the looper is rotated from this position, it is also retracted slightly so as to move the upper edge of the thread eye in substantially a horizontal plane.

To lay the thread in the needle hook, the looper is raised into its highest position and rotated from the angular position, shown in Fig. 24, to the position shown in Fig. 35, thus winding the thread through a bend of substantially 180 degrees about the needle before the needle is retracted from the horn. To present the needle properly to the looper the needle is turned about its longitudinal axis from an angular position at the upper end of its stroke which is fixed with respect to the line of feed to an angular position at the lower end of its stroke, which is fixed with respect to the horn. An advantage of the present looper is that it will act to thread the needle with certainty even if the angular positions to which the needle hook is turned vary considerably, theadjustment of the needle and its actuating needle mechanism being less critical than in the Topham machine.

After winding the thread about the needle, the tension on the thread is increased in a manner more fully described hereinafter, causing the thread to be pulled securely within the hook of the needle. To reinforce the needle when this added tension is applied tothe thread, the'angular end surfaces of the looper are so arranged that when the looper is rotated, after winding the thread about the needle, the end surfaces engage the needle at the rear of the open needle hook, as shown in Fig. 39.

After looping the needle, the looper is moved away from the tip of the horn until the stitch being formed is set. When the stitch is set, the looper reaches a position in which the thread extending between the thread eye 98 and the work passes at one side without engaging the upper end of the thread finger 92 so as to slide freely past the thread finger in either direction. The needle looper 94 is then'rotated in a clockwise direction, as viewed from above (see Fig. 19) to carry the thread beneath the hooked end of the thread finger, asillustrated in Fig. 17. Thereafter, the looper is again moved towards the tip of the horn ready to loop the needle at the end of its next work penetrating stroke, thus forming a bight of thread about the thread finger. After the needle is looped, a single movement only is required of the thread finger to release the bight as the needle begins itsupward stroke. The space required by the thread finger is thus much less than in the machine of the Topham patent, in which the thread finger is also moved across the looper to properly engage the thread therewith before the bight is formed. As a result of this construction, the dimensions of the upper end of the horn surrounding the thread finger of the present machine may be made smaller without afiecting reliability in sewing.

The thread finger 92 consists of a lever, the

hooked end of which is spaced a suitable distance from the needle opening 99 and the lower end of which is formed with an offset portion arranged to be engaged by the slotted upper end of a vertically sliding actuating bar I 00. The thread finger lever 92 is fulcrumed on a short sleeve I92 fitted in a passage within a removable tip piece I04 slidably mounted in a guideway I95 at the upper inclined end of the horn. The guideway for the tip piece I04 is so arranged that as the tip piece is slipped into place the lower offset end of the thread finger 92 will slide within the slotted upper end of the actuating bar I98, the slotted sides of the upper end of the rod extending in substantially the same direction as the sides of the guideway I95 for the tip piece. To secure the tip piece in place, a threaded stud I96 passes through one side of the guideway in the upper portion of the horn, through the sleeve I02 and into threaded engagement with an opening in the other side of the guideway.

' When the looper is in its lowermost position, shown in Fig. 16, the hooked end of the thread finger 92 extends over the end of the looper so that when the looper is rotated, the thread finger will pick up and form a bight in the thread. As the looper starts moving upwardly towards the tip of the horn, the hooked end of the thread finger is raised slightly to clear the looper with out releasing the thread bight (see Fig. 1'7). After the needle has been looped, the thread bight is finally released from the thread finger by raising the hooked end of the thread finger still further until the side edges of a slot I01 within.

which the upper part of the thread finger moves brushes the bight of thread therefrom.

To actuate the thread finger, the sliding bar I98 is pivotally connected, as shown in Figs. 16,

the horn. The lower end of the hub of gear I29 is dished and provided with internal gear teeth I26 meshing with a. planetary gear 128 rotatable on a stud I30 eccentrically mounted on a spur gear I 32. The gear I32 is rotatable about the central part of the shaft I22 and engages a similar gear I34 secured to the upper end of the shaft 22. v

To prevent rotation of the horn about its bearings from changing the angular position of the shaft 24, a diiferential system of gearing is provided comprising a ring gear I36 secured to the machine frame and a spur gear I38 with which the gear I36 meshes, attached to the lower end of the shaft I22. The shaft I22 is provided just above the gear I32 with a gear I49 which engages the planetary gear I28. This system of gearing causes the planetary gear I28 to revolve about the shaft I22 when the horn is held stationary. When the horn is rotated, the gear I32 will change its relation to the gear I34. Theposition of the gear I49, however, will also change when the horn is turned, thereby causing the helical gear I29 which is driven by the difference in rotation between the gear I 32 and the gear I49 to be maintained in its proper rotative position with respect.

to the horn.

When a rotary needle threading whirl and its driving mechanism, such as employed in the horn of the machine of the Ashworth or Leveque patents, becomes jammed with thread, or the resistance to its rotation increases from insufficient lubrication, the horn of the machine may be thrown suddenly into rotation on its spindle so as to jerk the shoe being operated upon out of the grasp of the operator. Not only is the operator likely to be injured, but damage to the shoe being sewed or to parts of the machine other than the looper may thus result. With the present system of differential gearing, the driving force of the gear I34 on the gear I32 tending to rotate the horn, is exactly equal and opposite to force of the gear I38 on the fixed ring gear I36, so that there is no tendency for the horn to rotate, regardless of the frictional or other driving resistances in the driving mechanism. The driving mechanism for the looper and the takeup may actually be broken with this arrangement without causing rotation to be imparted to the horn.

The mechanism for actuating the looper towards and from the tip of the horn comprises a swivel in the form of a washer shaped member M2 (see Fig. 22) at the lower end of the looper 94 and a cylindrical block I44 having a diametrically cut T-shaped slot within which the end of the looper and the washer member I 42 slide. Supporting the swivel is a lever I46, the upper end of which is forked and forms a bearing for the cylindrical block I44. The lower end of the lever M6 is connected to a pitman I48 (see Fig. 26) carried by a crank I59 on the shaft 24. The lever M6 is fulcrumed on a horizontal shaft I50 and is so arranged that when the shaft 24 is rotated the horizontal component of rotary motion of the crank M9 causes the looper to reciprocate from a looping position to a position where the thread eye 98 passes beneath the hooked end of the thread finger.

The mechanism for rotating the looper is also ctuated from the pitman I48, but through a separate train of connections between the looper and the pitman. This mechanism comprises elongated gear teeth I52 on the lower end of the looper engaging rack teeth on a rod I54 (see Figs. 20 and 26) slidingly mounted in a suitable guideway in the horn, a link I56 connected between the lower end of the rack rod I54 and one arm of a bell crank I58 fulcrumed on a screw stud I98 carried by the horn and a link I62 connecting the other arm of the bell crank with an angularly disposed arm of the pitman I48. The connections of the bell crank I58 and the pitman I48 are such that the vertical component of rotary motion causes th looper to be rotated in one direction while looping the needle and in the reverse direction while carrying the thread about the thread finger. The looper reciprocating and rotating connections actuate the looper through a regular sequence of movements to engage the thread alternately with the thread finger and with the needle.

After carrying the thread around the thread finger, the movement of the looper towards the tip of the horn causes the thread to slide rapidly through the thread eye 98 of the looper. On account of the relatively sharp angle through which the thread is bent as it leaves the thread eye, it is desirable to relieve somewhat the tension on the thread at this time. To this end beneath the hollow shaft 22 the thread passes through an intermittently actuated thread gripping device lfid (Figs. 14 and 15) against which the stitches are set. The gripping device is similar in construction to the sewing thread lock against which the stitches are set in the machine of the Topham patent, but is actuated to release the thread at a different time in the sewing cycle. The gripping device releases the thread in the present machine when the looper carries the thread around the thread finger and is held in releasing position until the looping operation of the needle is substantially completed.

The thread gripping device I6 3 comprises a washer supported near the forward end of the horizontal shaft 22 on a rock shaft I66 rotatable in bearings IB'I in the machine frame. At the rear end of the rock shaft is secured a lever I68 having a cam roll I!!! arranged to engage a cupshaped cam H2 secured to the shaft 20. Surrounding the central part of the rock shaft IE8 is a spring I14 compressed between one of the bearings I57 and a block I76 clamped by means of a set screw I18 to the rock shaft so that the spring I14 tends to press the hub of the lever I68 against the gripping washer H3 and force it against an enlarged hub I39 between which and the washer I94 the thread extending from a suitable source of supply I65 passes. The hub I88 is secured to said bearing IG'I so as to hold the thread when the washer IE4 is pressed against it. When the follower I is actuated by the cam I12, the shaft I66 is rocked and a pair of diametrically opposite projections I32 of the block I 5'6 are raised from a pair of correspondingly shaped recesses, one of which is shown at I84, in a block I86 mounted on the frame of the machine. When in this position the shaft IE5 is moved endwise and the grip on the thread released. The spring I'M is of proper size and strength to cause the gripping washer I66 to impart a stitch setting tension only to the thread, and to permit thread for a new stitch to be pulled past the washer from the supply after the stitch is set. When the grip on the thread is released during movement of the looper towards the tip of the horn, only a sufficient amount of thread is drawn past the washer to relieve the tension in the thread between the gripping device and the work.

Each stitch is set by the main take-up, indicated at I88, in Figs. 16 and 25, rotatably mounted on a shaft I39 passing through the side walls of the horn. The thread passing through the hollow shaft 22 is carried around the take-up shaft I90, about a pulley ISI' rotatable on a stud I92 in the horn and about a pulley E93 at the end of the take-up. The actuating mechanism for the take-up is driven by the shaft 24 and is mounted entirely within the confines of the lower part of the horn. The take-up is connected by means of a link I94 to a pivot I95 carried by a pitman I96. The pitman I96 is mounted on a second crank portion I98 on the shaft 24. To guide the movements of the pitman I96 between the pivot I95 and the crank I98, there is connected one end of a radius arm 253, the other end of which oscillates about a pin 252 mounted in the horn frame.

To increase the tension on the thread after the thread is Wound about the needle, the center of the pin 202 about which the radius arm 25!! oscillates is so located that during the movement of the take-up to give up thread, there is a short reversal. When the needle begins to rise, the take-up again begins to give up thread at the proper rate while maintaining the increased ten-