US2408523A - Presser foot mechanism for sewing machines - Google Patents

Description

v Def. 1, 1946; a. T. LEVEQUE PRESSER FOOT MECHANISM FOR SEWING MACHINES 1943 5 Sheets-Sheet 1 Original Filed June 25 w, a, w

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- Oct. 1, 1946. I i-r, LEVEQUE 2,408,523

PRESSER FOOT MECHANISM FOR SEWING MACHINES Original Fil ed June 23, 1945 5 Shee1 '.s- Shee t 2 v a. T. LEVEVQUE 2, j ,523 PRESSER FOOT MECHANISM FOR SEWING MACHINES 7 Original ,Fil'ed June 25, 1943 5 shets sheet s Oct. 1', 1946.

Oct. 1', 1946'. f B. T. LEVEQUE 2, 8,523

PRESSER FOOT MECHANISM FOR S EWING MACHINES v Original Filed June 23, 1943 Y 5 Sheecs Sheet 4 Oct. 1, 1946. T, LEVE UE 2,408,523

PRESSER FOOT MECHANISM FOR SEWING MACHINES I Original Filed June 23, 1943 5 Sheets-Sheet 5 ,zzgga Patented Oct. 1, 1946 UNITED STATE PRESSER FOOT MECHANISM FOR SEWING MACHINES Bernard 'i". Leveque, Wenham, Mass., assignorto United Shoe Machinery Corporation, Flemington, N. J a corporation of New Jersey Original application June 23,1943, Serial No. I

, 491,863. Divided and this application July 27,

1945, Serial No. 607,292 r 3 Claims. .(Cl, 112- 1) s The present invention relates toimprovements in sewing machines for operating upon shoes or 1 other articles composed of still, heavy materials and to'presser f-oot. actuating mechanisms particularly useful with machines of the type disclosed in United States Letters Patent No. 2,352,274, granted on June 27,. 1944, in the name of the present inventor, and in a copending application Serial No. 491,863, filed on June 23,1943, of which the present application is a division. v

The. machine of the patent and copending ap- 2 g operation for the purpose of rendering the machinefmore effective thanother similar straight needle machines and to obtain a more uniform operation and durable construction in the presser foot actuating .mechanism without-increasing substantially the external dimensions of the frame or other enclosing structure. Further ob: jects 'offthe invention are to simplify and im prove the effectiveness of a presser foot actuating mechanismin other respects and generally 7 to provide a machine which will sew heavy Work plication is provided with a reciprocating straight i needle and a straight awl actuated by relatively simpleconnections from the main sewing shafts. The work operated upon is clamped in position in each sewing cycle between a work support and a pres'ser foot actuated intermittentlyto release thework for the feeding movement.

In the design of a straight needle type of sewing machine, an important problem is in obtaining within the confines of a relatively small space a construction for moving the operating parts which may be enclosed completely or otherwise protected from accidental contact. If the outside dimensions of the machine, particularlyin a'horizontal direction from onesideiof the machine to theother, are bulky, the operators line of vision or the light atv the sewing point will be obscured to an. objectionableextent andthe work 1 operated upon will be limited to that "of relatively flat nature or to straight edged types of work requiring no special attention to guide them through the machine. Bulky construction of a machine also renders itextremely difficult to 0perate upon work having curved or angular outlines, as is often encountered when sewing shoes, small instrument cases and similar articles.

. With a straight needle machine, operating mechanism provided with a presser foot supportingand reciprocating bar is most practical. To obtain a tight and easily operated mechanism, the actuating connections for the presser foot bar preferably are yieldingly actuated and positively locked while the work is released as Well as while'clamped. To enable uniform yielding engagement of the presser foot with the work positively in and possess ability. to operate above tho'selspeeds now-in, customaryuse without the exercise of special skill or'flmaintenance'of. careful adjustm'e'ntin'the machine by the operator. I ,i'

The illustrated machine embodying the features of the present invention according to these and other objects comprises'stitch forming de-' vices-a work support, a'jpresser foot, a sliding spring-pressed presser foot bar for, urging the presser yieldingly against the work upon the work support to clamp'it in sewing position together with means .for actuating the presser foot two directions both toward and from the work during each sewing cycle, including a lock supporting block slidingly mount ed directly on the presser foot bar, and a twoway clutch in theblock for lockingthe block to the presser footbar. By this construction, the presser foot bar when unlocked may be urged yieldingly toward the Work to clamp the work, the sliding block remaining stationary so as not to add, to the weight and the inertia of the presser foot and presser foot bar. Thus, the slight yielding movement required to move the presser foot and bar may be accomplished quickly and without substantial impact on the work at the end of the movement andit is not necessary to readjust the presser foot actuating mechanism for different thicknesses of work. I

' In additionto these "features, still other 'features of the inventio'ri'are embodied in certain constructions; combinations and arrangements of parts hereinafter'de'scribed and claimed, the

advantages of which wil'l'be readily understood at high speeds, particularlyfwhen the thickness from the following detailed description. Referring to the drawings,

Fi 1 is a view in front elevation of a machine embodying the features of the present invention; Fig. 2 is a front view, on an enlarged scale, of the-upper portion of the machine illustrated in Fig. l with a front cover'removed, exposing the needle and presser foot actuating mechanisms;

Fig. 3 is a detail front view of the presser foot actuating mechanism in a position taken during sewing operations while the presser foot is locked against the work; v I

4 is a detail front view of part of the mech anism illustrated in Fig. 3 in position after the machine is stopped and the presser foot lifted from engagement with the work to enable the work to be removed;

Fig. 5 is a partial sectional detail view of the parts illustrated in Fig. 3 taken during the sewing operations, with the presser foot still locked against the work but about to be raised to permit the work to be fed a stitch length;

Fig. 6 is a similar view of the same parts, taken while the presser foot is being lowered against the work;

Fig. 7 is a similar view of the same parts, illustrating the positions with the presser foot unlocked so that it may adjust itself yieldingly to the thickness of the work;

Fig. 8 is a detail view in left side elevation of the parts illustrated in Fig. 5;

Fig. 9 is a detail View, looking from the rear of the presser foot lock, taken along the line IX-IX of Fig. 8; and

Fig. 10 is a sectional View of the ,presser foot bar and lock, taken along the line X-X of Fig. 9.

The sewing machine illustrated in the draw ings is a chain-stitch, eye-pointed, straightneedle machine having a straight awl operating from below and the needlefrom above the work. A work feeding movement is imparted to the awl while engaging the work to advance the work'a stitch length. To form a loop in the thread carried by the needle and hold .the loop in position during the succeeding sewing cycle for the. entry of the needle, the machine is equipped with an oscillating loop taker (not shown) acting at the same side of the work with the awl, all of the stitch forming devices being driven from parallel operating shafts through cams, cranks, pitmans and other suitable connections, as in the machine of inventors patent and copending application above identified. To facilitate lubricating the machine, the operating and driving mechanisms are entirely enclosed by an oil-retaining .hollow supporting frame or casing ,2 having at its upper portion an overhanging arm and at its lower portion a base, within which arm and base are arrangeddistributing means including an oil pressure pump and spray and drip delivery jets (not shown).

In the illustrated machine, the needle is shown at 4, the awl at 6, and the operating shafts comprising main sewing and auxiliary shafts at 8 and H1 in the frame and base positions. The operating shafts are driven in unison through suitable driving connections,

Trains of connections for the needle and awl actuating mechanisms, in the illustrated machine as in the machine of the patent and application, I 5

include elements movable to disconnect both the needle and awl separately and to bring them to rest at the opposite ends of their respective reciprocating strokes. The disconnectible elements of the connections comprise parts of a driving and stopping mechanism, to be more fully described hereinafter.

Referring more particularly to Figs. 2 and 3. the train of needle actuating mechanism comprises a co-untershaft l2 witha crank l4 thereon, driven from the main shaft '8, and a pitman l6, one end of which surrounds the crank and the other end of which is pivotally connected to one arm of -,a three-armed lever l8 fulcrumed on a shaft 2e secured between spaced supports on a bracket 22 mounted within the upper portion of the machine frame. Another arm of the threearmed lever 18 is connected through .a link 24 (see Fig. 6) toacurved driving lever 26 fulcrumed on acentral portion of a horizontal rockshaft 28 4 loosely supported in bearings formed in lugs pro- Jecting inwardly of the machine frame. When the machine is stopped, the driving lever 26 is free to oscillate without imparting any reciprocating movement to the needle but, during sewing, a pin 3 carried by the curved end of the lever 26 is engaged by the lower hooked inner end of a latch link 32 pivoted on a pin 34 secured at the end of the needle actuating lever 35 loosely fulcrumed on the rockshaft 28. To maintain the latch link in engagementwith the pin 30 during sewing, a spring-38 is coiled around a hub on the link and acts to swing the link in a counterclockwise direction. The lever 35 is in turn pivotally connected through a short link 4!] to a block 42 secured on a vertical reciprocating needle supporting bar M.

For shifting the needle latch link 32 to connect or disconnect the needle, a needle controller shaft 55 is provided, mounted in suitable bearings at the right and above the operating shaft 8, At the outer end of the needle controller shaft 45 isa shift lever 48, the upper end of which has a slotted locking piece 5! and a latch finger 52 clamped to its opposite sides. The latch shifting finger is so located that, when the actuating lever is in its highest position, counterclockwise movement of the shift lever t8 will cause the latch shifting finger to engage the latch link 32 and swing the latch link clear of the pin 30, thus discormecting the needle bar from its actuating mechanism. At the same time, the slotted looking piece 5d engages the outer end of the pin 34 to hold stationary the needle actuating lever 36 and the needle bar connected thereto in their highest positions, thus stopping sewing operations. To hold the needle controller shaft 45 and shift lever 48 in either starting or stopping position, the rearward end of the shaft is connected with mechanism under control of a vertical treadle rod '5 described more fully in the copending application to which reference may be had for a more complete disclosure.

The train of the awl actuating mechanism is generally similar to that for the .needle.

The work is secured in sewing position against the thrust of the awl operating from beneath the work in a well-known manner. The work rests upon a stationary work support, indicated at 56, and is clamped by a presser foot 58 acting on the upper surface of the work. The work support is in the form of a plate secured to the lower base portion, of the enclosing casing 2 and the presser .foot is secured to a reciprocating barfifi slidingly mounted in suitable bearings in the overhanging arm portion of the casing. To bring the presser foot yieldingly against the work during each sewing cycle, the upper end of the presser foot bar is surrounded by a spring 52 engaged at its ends with a shoulder on the bar and a sleeve 64 threaded in the machine frame.

To actuate the presser foot toward and from the work and to lock the presser foot in engagement with the work so that the work may be fed freely and thereafter be secured against movement during formation of each stitch, the third arm of the three-armed lever I 8 carries a cam roll 66 (see Figs. 2, 3, 5, '7 and 8) engaging a suitably formed cam slot 68 in an arm 1B clamped to the rearward end of the rockshaft 23. The forward end of the rockshaft has clamped to it a slotted arm 72 in the slot of which is adjustably secured a bolt 74 forming the pivotal connection for the upper end of a link 15, the lower end of which is pivoted to a presser foot lock supporting block 18 slidingly mounted on the presser foot reciprocating bar. 60. When the presser foot bar is locked to the block 18, movement of: the three-armed lever It! causes: the presser'foot to be lifted from or lowered against the work through direct-acting, non-yielding mechanism, the shape of the cam slot 68 being such that positive movements in two directions occur during dwells while the needle and awl are at the upper end of their reciprocating strokes. During the remainder of each sewing cycle, the presser foot actuating mechanism remains stationary with the presser foot locked in engagement with the work.

The means for locking the presser foot to the locksupporting block is of a novel and improved construction particularly efiective for high-speed actuation, the operating time requiring but a relatively small fractional part of each sewing cycle. In certain respects, the mechanism for actuating the presser foot in the presentapplication is similar to that of United States Letters Patent No. 2,321,032, granted on June 8, 1943, in the name of the present inventor, in which there is disclosed an oscillating two-way clutch for looking a reciprocating presser foot bar. In order to connect the presser foot bar of said Patent No. 2,321,032 with the oscillating clutch, link connections are required which add inertia to the parts and in turn tend to increase the forces required to move the parts with rapidly accelerated motion. Accordingly, a longer time is required to raise and lower the presser foot during each sewing cycle than where the connections are of lighter weight; In the present improved presser foot mechanism, the two-way clutch for locking and unlocking thepresser foot acts directly on the presser foot bar without the use of any separate connections between the lock and the bar. Thus, a lighter'spring 62 may be employed to urge the presser foot against the work with the certainty of reliable work clampin action. With the use of a lighter spring, there is less danger of marking or injuring the work from impact during engagement by the presser foot.

Referring to Figs. to 10, inclusive, the presser foot locking clutch is of the two-way roll type yieldingly actuated toward locking position and positively actuated toward releasing position. The rolls of the clutch are indicated at 80 in Figs. 5, 6 and 'l loosely mounted in an opening within the lock supporting block I8. The rolls Bil-are backed by springs 82 compressed'between the'rolls and retaining plates 84 removably secured to the supporting block 18. The rolls 8!! are moved toward locking positions by the springs 82 which force the rolls along oppositely inclined surfaces toward each other in the supporting block to wedge the rolls against a hardened fiat wear plate 86 embedded in a side surface of the presser loot bar 60. To release the presser foot bar, the rolls are forced apart by a wedge 88 fixed to the inner end of a slotted slide 90 movable horizontally in a uideway within the lock supporting block 18.

To actuate the lock releasing wedge 88, a pivot 92 having a central eccentric disk portion passes through the slot in the slide 90 and has its ends mounted in bearings in the sides of the supporting block outside of the slide 90 (see Fig. Clamped-to the rearward end of the pivot 92 is a trigger 94 projecting into the path of a trip finger 96 the hooked portion of which is shaped to retain the trigger 9 4 while the lock supporting block 18 is descending toward the work (see Fig. 6) When the trigger is engaged by the hooked locking mechanism end of the trip finger at the end of the descent of the lock supporting block, the eccentric disk portion on the pivot 92 presses the wedge slide toward the presser foot bar and separates the rolls 80 .(Fig. 7) to unlock the presser foot bar and to enable the presser foot to engage the work yieldingly. 1 The trip finger 86 is pivotally supported by a screw 98 in a lug on the needle driving lever 26. After releasing t e lock, the trip finger is moved away from the trigger by the engagement of a stop on the trip finger with a projection I00 on the lever 25. To holdv the trip finger in a position where it will engage the trigger, the screw 98 is surrounded by a coiled spring I02 acting at one end on the needle driving lever-and-at the other end on the trip finger, the trigger being beveled at its outer end to-force the trip finger out of the. path of the trigger (Fig. 5) during upward movement of the lock supporting block and presser foot. The presser foot actuating and is so adjusted that the presser foot bar is released from the look only after the presser foot has been lowered substantially into engagement with the work; In this way, little'or no. movement of the presser foot bar from the force of the presser 'foot spring 62 occurs after the presser foot engages the work. As a result, the presser foot may be operated at relatively high speeds with minimum relianc upon the force of the spring 62 to bring the presser foot accurately against the work.

For lifting the presser foot from engagement with the work after a seam has been completed in order that the work may be withdrawn from the machine, the presser foot is first unlocked, and a roll I04 projecting forwardly from the presser foot bar is engaged by a lever I06 pivotally mounted on a fixed screw I08 (see Figs.'3 and 4). The left end of the lever has clamped to it a block H0 supporting. a lock releasing roll H2 acting when raised against a cam surface on an arm I 14 secured to the forward end of the eccentric pivot 92 ofthe presser foot lock to release the presser foot'bar from the lock. One arm of the lever M6 is connected to a toggle comprising a'link H6 and an arm 1 it! fast to the forward end of the needle controller shaft 46. With the controller shaft in starting position, the toggle'is broken with the central joint out of alinement with the end'pivots (Fig. 3) and the roll-l l2 and its actuating lever are held in lowered position out of engagement with the lock releas ingarm H4 and th presser foot liftingroll I04. When the needle controller shaft 46 is rocked to stopping position, the'partsassume the relations illustrated in Fig. 4.

To prevent the presser foot locking rolls from being accidentally disengaged from the plate 86 on the presser foot bar, a downwardly extending lug on the releasing arm ilis connected t one end of a tension spring I29, th other end of whichis madefast-to a lug on the lower end of the link 15, a stop lug 122 being provided on the lock releasing arm H4 (see Fig. 8) to engage the supporting block 18 and limit the movement of the lock releasing arm H4 under the action of the spring 120. The spring thus holds the releasing arm in'inoperative position'except when positively actuated. The nature and scope of the invention having been indicated and a particular embodiment having'been described. what is claimedis:

: l. A sewing machine having, in combination,

stitch forming devices, a Work support, a presser foot, asliding spring-pressed presser foot bar for urging the presser foot yieldingly .against the work-on .the work support, and means for actuating the presser foot positively toward and from the work during each sewing cycle, comprising a lock supporting block slidingly mounted on the presser foot bar, mechanism acting in two directions to move the block, and a two-Way clutch for :locking the block to the presser foot bar.

2. A sewing machine having, in combination, stitchiforming devices, a work support, a presser foot, a sliding spring-pressed presser foot bar for urging the presser foot yieldingly against the work-on the work support, and means for actuating the presser foot positively toward and from the work during each sewing cycle, comprising a lock supporting block slidingly mounted on the presser foot bar, mechanism acting in two directions to move the block, a two-way clutch for locking the block .to the presser foot bar, and a trigger on the lock supporting block actuated at the end "of the movement of the supporting block towards the work 'to unlock the block from the presser foot bar.

3. A sewing machine having, in combination, stitch forming devices, a work support, a presser foot, a sliding spring-pressed presser foot bar for urging the presser foot yieldingly against the work on the work support, and means for actuating the presser foot positively toward and from the work during each sewing cycle, comprising a lock supporting block slidingly mounted on the presser foot bar, mechanism acting in two directions to move the block, a two-way clutch for locking the block to the presser foot bar, a trigger on the lock supporting block actuated at the end of the movement of the supporting block towards the work to unlock the block from the presser foot bar, and ielding means for actuating the trigger in the opposite direction to cause the block to be relocked to the bar.

4. A sewing machine having, in combination, an eye-pointed needle at one side of the work, an awl at the other side of the work, a work support at the side of the work with the awl, a presser foot at the side of the work with the needle, mechanisms for actuating the needle and awl, a sliding spring-presSed'pre-Sser foot bar, and means for actuating the presser foot toward and from the work during each sewing cycle, comprising a lock supporting block slidingly mounted on the presser foot bar, connections between the needle actuating mechanism and the lock supporting block for-moving the block positively in two directions, a two-way clutch for locking the block to the presser foot bar to hold the work againt the thrust of the awl and to lift the presser foot from the work during work feed, and means for unlocking the bar from the clutch in each sewing cycle.

5. A sewing machine having, in combination, an eye-pointed needle at one side of the Work, an awl at the other side of the work," a work'support at the side of the work with the awl, a presser foot at the side of the work with the needle, mechanisms for actuating the needle and awl, a sliding spring-pressed presser foot bar, and means for actuating the presser foot towards and from the work during each sewing cycle, comprising a lock supporting block slidingly mounted on the presser foot bar, connections between the needle actuating mechanism and the lock supporting block for moving the block positively in two directions, a two-way clutch for locking the block to the presser foot b'arto hold the work against the thrust of the awl and to lift the presser .fo'ot from the work during work feed, means .for unlocking the bar "from the clutch in each sewing cycle, a trigger on the lock supporting block to unlock the block from the bar, and a trip finger operated by the needle actuating mechanism acting to engage the trigger at the end of the movement of the supporting block and to disengage the trigger while the presser foot engages 'the'work.

'6. Asewing machine having, in combination, an eye-pointed needle at one side of'the work, an awl at the other side of the work, a work support at the side of the 'work with the awl, a jpre'sser foot at the side of the work with the needle, mechanisms for actuating the needle and awl, a sliding spring-pressed presser foot bar, and means for actuating the presser foot toward and from the work during each sewing cycle, comprising a lock supporting 'lolock slidingly mounted on the presser foot "bar, connections between the needle actuating mechanism and the lock supporting block for moving the block positively in two'directions, a two-way clutch for locking the crock "to the presser foot bar to hold the work against the thrust of the awl and to lift the presser foot from the work during work feed, a trigger on the locksupporting'block to unlock the hlock'from the bar, 'a trip finger pivotally mounted on a part of the'needle actuating mechanism, yielding means for urging the trip finger toward the path of the trigger while the lock supporting block is-be'ing moved, and a projection on said part'of the needle 'actuating mechanism for moving the trip finger away from the trigger.

7. A. sewing machine having, in "combination, stitch forming 'd'evices,a work support, a presser foot, a sliding spring-pressed presser foot bar for urging the presser foot yiel'dingly against the work on the work support to clamp the work in sewing position, and means for actuating the presser foot positively toward and from'the work during each sewing cycle, comprising a lock'supporting block slidingly mounted on the presser foot bar, mechanism acting in two directions to move the block, atwo-way clutch for locking the block to the presser foot bar, stopping connections for stopping the operation of the machine, a lockreleasin'g'arm connected to the clutch, and a -lever in said stopping connections for actuating said lock releasing arm and lifting the "presser foot from clamping engagement with the work.

'8. A sewing machine having, in combination,

' stitch forming devices, a work support, a presser foot, a sliding spring-pressed presser foot bar for urging the presser foot yieldingly against the work on the work support to clamp 'the'work in sewing position, driving control connections for stopping the operation of the machine, and means for actuating the presser foot positively toward and from the work during each sewing cycle, comprising a lock supporting block slidingly mounted on the presser foot bar, mechanism a'ct ing in two directions to move the block, 'a twoway clutch for locking the block to the presser foot bar. a trigger for releasing the clutch during each sewing cycle, a lock releasing arm connected to thetri'gger, and a lever connected to said driving'control connections for actuating said lock releasing arm and for lifting the presser-foot from clamping engagement with the Work when the sewingoperat-ions are stopped.

BERNARD .I', LEVEQU'E.

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