US2836137A - Presser foot lifter and spring tensioning mechanism for a sewing machine - Google Patents

Description

May 27, 1958 w. A. AYRES 2,836,137 PRESSER FOOT LIFTER AND SPRING TENSIONING MECHANISM FOR A SEWING MACHINE Filed July 21, 1955 L\ \ll INVENTOR.

WALDEMAR A. AYRES F|G3 BY A 35 ATTORNEYS United StatesPatent Ofitice I V PRESSER FOOT LIFTER AND SPRING TENSlON- ING MECHANISM FOR A SEWING MACHINE Waldemar A. Ayres, Lakewood, Ohio, assignor to White Sewing Machine Corporation, Lakewood, Ohio, a corporation of Delaware This invention relates to a sewing machine presser foot lifter and spring tensioning mechanism.

It is customary to provide in sewing machines adjacent to the reciprocating needle bar in the head a vertically movable presser foot rod to the lower end of which the presser foot is secured.

This presser foot rod usually is moved in a downward direction under the action of a spring to cause the presser foot carried by the lower end of the rod to engage the material being sewed with a required pressure.

It is also usual to provide means for raising the rod and the presser foot upwardly against the action of the spring means to a position wherein the presser foot is out of engagement with the material so that the latter can be freely moved from beneath the presser foot when the sewing operation is completed or can be moved for other purposes. Ordinarily there is provided some means for retaining the presser foot and rod in the raised position until it is desired to lower the same to their lowermost positions.

An object of the invention is to provide an improved presser foot lifting and spring tensioning mechanism for a sewing machine which is simple in construction, efficient in operation and can be readily manipulated by the operator.

Another object of the invention is to provide an improved and novel presser foot lifting mechanism whereby the presser foot and the presser foot rod can be raised from lowermost operative position to a plurality of predetermined lifted positions and will be effectively held in any of said lifted positions.

A further object is to provide a presser foot lifting mechanism such that when the rod and presser foot are in maximum or high lifted position the same can be swung or rotated on the axis of the rod from their normal operative sewing position to an angularly spaced position so the the presser foot will not be in alignment with the needle bar and the latter is more readily accessible for the mounting therein of a needle or for connecting thereto an operating part of a buttonhole, zigzag or other form of attachment.

Another object is to provide a presser foot lifting mechanism such that the presser foot and the presser foot rod can be raised from lowermost position to various predetermined lifted positions and cannot be fully moved from lifted position to lowermost position by the presser foot rod spring except under the positive control of the operator, thus obviating the danger of damaging the presser foot by the latter being forcibly and rapidly moved by the spring from a lifted position to its lowermostposition which would cause the presser foot to strike the needle plate with a sharp blow.

Another object is to provide in a presser foot lifting mechanism means whereby the presser foot except when in its maximum or high lifted position automatically will be properly related to the needle carried by the needle bar so said needle will be aligned always with the opening in the-presser foot topass through said opening during the presser foot which would cause damage to or break age of the needle.

A further object is to provide improved and novel means for adjusting the tension of the presser foot rod spring and which means includes provision for readily releasing the tension on the spring and then readjusting the same to a desired calibrated adjustment.

A still further object is to provide a presser foot lifting and spring tensioning mechanism which includes a control lever for the lifting movements and a control lever for the spring tensioning adjustments with both of said levers extending to the front of the head of the sewing machine and to a position where they are readily accessible to the operator when the latter is using the machine for sewing operations.

Further and additional objects and advantages not hereinbefore expressly referred to will become apparent hereinafter during a detailed description of an embodiment of the invention which is to follow and which embodiment is illustrated in the accompanying drawing forming a part of this specification and wherein,

Fig. 1 is a sectional view through the head of a sewing machine and is taken substantially on line 11 of Fig. 5 looking in the direction of the arrows and illustrates in elevation the presser foot lifter and spring tensioning mechanism embodying the present invention, with the parts of said mechanism shown in full lines in the positions they occupy when the presser foot is in its lowermost or sewing position and in dot and dash lines when the presser foot is in its intermediate or low lifted position, at which time the presser foot is out of engagement with the material being sewed.

Fig. 2 is an end elevational view of the presser foot lifter and spring tensioning mechanism and shows the relationship of the parts of the lifter mechanism when the presser foot is in its maximum or high lifted position, the presser foot and the presser foot rod being turned from the positions they occupy in Fig. 1.

Fig. 3 is a sectional view taken substantially on line 33 of Fig. 1 looking in the direction of the arrows.

Fig. 4 is a top plan view of Fig. 2 with the presser foot rod and presser foot shown in full lines when they are in the unturned position of Fig. 1 and in dot and dash lines when they have been swung from the unturned position to a slightly turned position wherein the presser foot still underlies the needle but the needle opening in the presser foot is not aligned with the needle or when they have swung still farther to a turned position wherein the presser foot has moved out of aligned position with the needle carried by the needle bar, and

Fig. 5 is a fragmentary front elevational view of the free end of the head of the sewing machine.

It will be understood that the head of the sewing machine comprises a vertical portion, not shown, which extends upwardly from the bed of the sewing machine, the plane of which bed is indicated at 10. The upper end of the vertical portion of the sewing machine head has a hollow horizontal arm extending therefrom and overlying the bed and at the free end of this horizontal arm is a downwardly extending portion in which are located the vertically reciprocating needle bar and the presser foot rod. It will also be understood that the head supports interiorly thereof other operative parts of the sewing machine and which are operatively connected to still other operative parts located beneath the bed.

The portion of the head containing the needle bar and the presser foot rod is indicated in Fig. 5 at 11. The head includes an outer enclosing casing within which are mounted the supporting structures for the operative parts of the sewing machine.

The supporting structure for the reciprocating needle Patented May 27, 1958.

"bar an'dthe presser foot rod is will be noted that the sides and top of said structure :areSpaced inwardly of thecasing 11. .The vertically reciprocating needle bar 13 is suitably mounted in the indicated at 12 and it structure 12 and projects through an opening in the 1 bottom ofthe casing 11 as will be well understood, but

which does not have to be described in detail herein since it constitutes no part of the present invention.

bottom thereof is cut away to provide .a chamber 14 and above and below this chamber is provided with aligned bores in whichthe'pres'ser foot rod 15 is slidably mounted, said rod passing through thechamber' 14.

The upper end'o'f the supporting structure12 is provided witha'vertically elongated slot 16 communicating 1 with the bore in the upper end of the supporting structure in whichthepresser foot rod 15 .slidesv The slot 16 is parallel. to the bore and'the presser foot rod 15 audits upper end is'fiared on a radius as indicated at 17 to provide a carnrning surface for a purpose later to be explained. 7

The presser foot rod 15 mounts'a pin 18 which is slid-- "thepawl 31with the pawl teeth.

The lever 24 extends beyond the plate 29 and passes biased by its inherentflexibility in a direction to engage through a vertical opening 32 in the casing 11 at the front side of the'sewing machine head. .The lever 24 outwardly of the casing 11 is provided with an operating grip portion 33 and inwardlyof the grip portion with a pointer 34 that cooperates with a scale 32aformed on.

the front side of the sewing'machine head adjacent'to the slot 32 which'is calibrated in terms of tension of the spring 22.

it will be seen that the operator may adjust the ten- V 24 located conveniently at the front side of the head able in and guided by the slot l except when the presser foot rod is in its maximum raised or high lifted position as will laterbe referred to. V

The inner vertical wall of the chamber 14 in the supporting structure 12 is provided with a vertically extend ing .guideway 19. A lift block 20 freely movable on the presser foot rod is provided on one side with a milled or'otherwise formed guide channel cooperating,

It will be noted that when the presser foot rod15 is in its lowermost or full line position of Fig. '1 and the presser'foot is in contact with the bed of the sewing machine the lift-block has bottomed on-the lower end of the chamber 14 of the supporting structure but that the'collar 23 at this time is spaced above the upper end 5 of the lift block'20. This relationship is important as it assures the presser foot being held in operative or sewing position under spring tension even though the lift block 20,is in positive engagement with the supporting structure at the lower end'of the chamber 14. i V

A spring tensioning adjusting lever 24 has one of its ends pivoted to the supporting structure 12 as indicated at 25 while intermediate its ends the lever 24 is provided with an elongated slot 25a into which extends a pin 27 attached to a laterally projecting portion 26 of the spring abutment block 21., j

. The spring tensioning adjustiuglever 24extends' through an opening 28 formed in a plate 29 secured to the supporting structure 12. One of the vertical side edges of r the slot 28 is provided with ratchet teeth '30 so formed that the --cooperating-pawl 31 shown as integral with the lever "24 can ratchet'over the teeth 30 only in a downward direction, but when'the pawl 31 is in engagement with the teeth 30 it will be held thereby against movement in an upward direction. V

The lever 24 preferably is so dimensioned and formed of'a material having inherent flexibility, such as metal, and the locations of the pivot 25 and of the operative connection 27 are. such that the lever 24 is normally of its pivot 36 is provided with an elongated slot 37 'into which extends a pin 33 fixed in the .lift block 20. The lever is so pivoted to' the supporting structure 12 and so operatively connected to-the lift block 20 by the pin 38 and slot 37 that it canhavelimited lateral move- 7 ment.

The lever 35 extends through a vertical slot in the plate 29. This'slot includes a lower .portion .39 and an upper portion '40, the .lefthand side of the :portion 40 vertically aligning with the right hand side of the portion '39. The upper end of the portion .39 and the lower end of the portion -40 merge into a downwardly inclined connecting portion 41, a downwardly inclined top wall 41a and an upwardly inclinedbottom wall 41b.

The lever 35 where it passes through the slotin the plate 29 is provided with inclined top and bottom inclined surface portions 35a and 35b to cooperate with the walls 41a and 41b. The lever 35 passes through a vertical slot 42 in the casing 11 and which is similar to the slot just described-in the plate .29. The lever 35 outwardly of the casing 11 at the front of the-sewing machine head is provided with an operating handle 43.

The lift block 20 on its side opposite to the-way'19 has two vertically spaced laterally displaced straight parallel- sideportions 44 and 45 interconnected by an inclined camming portion 46. A slidable detent pin 47 carried by the supporting structure 12 has its inner rounded end arranged to engage and ride upon the portions, 45 and 46 and to engage in the recess 45a-in the portion-45 in a certain position of the slide block 20. v

A substantially U-shaped spring 48 is secured to the outer side of the supporting structure 12 by an adjusting screw 49 passing substantially centrally through the base of the spring 48 and adjustably screwing into'the structure 12. One leg of the U-shaped spring 48 bears against the structure 12 while the other leg thereof engages in a slot in the head of the detent pin 47 and appliesto the pin a spring load acting to move said pin'inwardly into contact with the lift block'20.

A needle N is shown mounted in the lower end of the needle bar .13 while a presser foot P of any desired cons struction is'shown attached to'the lower end. of therod 15 in any preferred manner. 7 V a In Fig. ,1 the presser foot P is showninfulllines in its lowermost operative sewing position andiin proper aligned relationship to the needle N while the liffblock 2 0 is bottomed at the'lowerend "of the IChElHlbCfl,

it being noted that thecollar 23 is spaced abovethe upper. end of the block 20rso .the1 presserifoot is :pre ssed downwardly into engagement with the material by the spring 22. Also at this time the rounded inner end of the detent pin 47 is engaging the surface portion 44 of the block 20, the lift lever 35 is adjacent to the lower end of the slot portion 39 in the plate 29 and the pin 18 on the rod is adjacent the lower end of the slot 16.

If the operator now wishes to raise the presser foot to the low lift position for any reason, the lift lever 35 is raised from the full line position of Fig. 1 to the broken line position thereof where it is at the upper end of the slot portion 39. If it is desired to retain the presser foot in the low lift position, the lever 35 can be moved laterally in the slot portion 41 and the surface portion 35b of the lever engaged with the inclined wall 41b. At this time the presser foot will be in the broken line position of Fig. l as also will be the lift block and the pin 18 in the slot 16. The inner end of the detent pin is now engaging the surface portion 45 of the block 20 adjacent to the camming surface 46.

If it is desired to raise the presser foot P to the high or maximum lift position from either of the two positions shown in Fig. l the lever is raised to the position shown in Fig. 2 at which time it will be at the upper end of the slot portion 49 in the plate 29. The spring 22 will now be fully compressed while the inner end of the detent pin 47 will be engaged in the recess a of the lift block under the load of the spring 48 to hold the rod 15 and the presser foot in the maximum raised position. Also at this time the pin 18 will have passed out of the upper end of the slot 16.

If the needle bar and needle are in their uppermost position the rod 15 and presser foot P can be swung from the full line position of Fig. l to the position of Fig. 2, at which time the pin 13 will have moved out of alignment with the slot 16 and the flared camming upper end 17 thereof and will overlie the upper end of the structure 12 to act as a positive stop against the rod and presser foot moving downwardly under the action of the spring 22. When it is desired to lower the rod and presser foot they can be swung in the opposite direction to align the pin 18 with the slot 16 and then the operator can control their downward movement by the lever 35 to release the detent pin 47 from the recess 45a and to control the action of the spring 22.

If the presser foot P and rod 15 have been raised to maximum lift position and have not been swung from the full line position of Figs. 1 and 2 wherein the needle N is aligned with the opening in the presser foot and the machine is inadvertently started, the descending needle bar will contact the presser foot after the needle 2 passes through the opening in the latter and will cause the detent pin 47 to be cammed out of the recess 45a whereupon the spring 22 will move the rod and presser foot rapidly downwardly. However, the presser foot cannot strike the bed of the machine or the'feed dog thereof and damage the presser foot since the lever 35 will engage the wall 411) of the slot in the plate 2? and the downward movement will be positively arrested. It will be noted that the wall 41b is upwardly inclined to assure against the lever 35 moving into the slot portion 39 under such circumstances.

Further assuming that the presser foot P and rod 15 are in their maximum raised position but have only been swung slightly from the operative position of the presser foot, i. e. from the full line position of Fig. 4 to the first broken line position therein, then the presser foot would still be in the path of the needle and needle bar although the needle opening in the presser foot would be out of alignment with the needle. If the sewing machine should inadvertently be operated and the needle bar and needle descend, the latter engaging the presser foot would exert sufiicient force thereon to cause disengagement of the detent pin 47 from the recess 45a and free the rod 15 and the presser foot P for downward since the pin 18 was overlying the flared camming upper end 17 of the slot 16, the downward movement of the rod 15 causes the pin 18 to be swung by the camming action of the end 17 into alignment with the slot 16.

This, of course, swings the rod and presser foot into. proper operative position with the needle opening in the.

presser foot aligning with the needle so the latter can pass therethrough without being bent or damaged.

The description hereinabove given of the mechanism embodying the invention clearly shows that the objects and advantages herein specified are fully attained.

Although a preferred embodiment of the invention has been illustrated and described herein, it will be understood that the invention is susceptible of various modifications and adaptations coming within the scope of the pended claims.

Having thus described my invention, I claim:

1. A presser foot lifter mechanism for a sewing machine comprising a supporting structure forming part of the sewing machine head, a presser foot rod vertically slidably mounted in said structure, abutment means fixed to said rod, spring means acting on said abutment means and urging said rod in a downward direction, a block slidable on said rod and in said structure being operatively associated with said abutment means and movable in an upward direction to lift said rod against the action of said spring means, a presser foot rod control member movably connected to said structure and operatively associated with said lifting means to move the same, means for maintaining said lifting means and said rod in an intermediate or low lifted position, and means for maintaining said lifting means and said rod in a maximum or high lifted position including a recess formed in said block and a' spring pressed detent carried by said structure and slidably engaging said block and arranged to be seated in said recess.

2. A presser foot lifter mechanism for a sewing machine head comprising a supporting structure forming part of the sewing machine head and provided with a vertical slot, said slot having upper and lower portions with the said portions laterally displaced relative to each other and interconnecting at their adjacent ends by a connecting portion angularly disposed to said upper and lower portions and providing a stop shoulder at the lower end of the upper portion, a presser foot rod vertically slidably mounted in said structure, abutment means fixed to said rod, spring means acting on said abutment means and urging said rod in a downward direction, rod lifting means operatively associated with said abutment means and movable in an upward direction to lift said rod against the action of said spring means, a presser foot rod control member movably connected to said structure and extending through said vertical slot and operatively associated with said lifting means to move the same and arranged to engage said stop shoulder to arrest downward movement of said rod under the action of said spring means, means for maintaining said lifting means and said rod in an intermediate or lower lifted position, and means for maintaining said lifting means and said rod in a maximum or high lifted position.

3. A presser foot lifter mechanism as defined in claim 2 and wherein said stop shoulder is upwardly inclined while said control member is provided on its underside with a similarly inclined surface portion adapted to cooperate with said stop shoulder.

4. A presser foot lifter mechanism as defined in claim 2 and wherein said connecting portion of said slot is provided with a downwardly inclined wall at the upper end of the lower portion of said slot, while said control member on its upper side is provided with a similarly inclined surface adapted to cooperate with said wall.

5. A presser foot lifter mechanism for a sewing machine comprising a supporting structure forming part of the sewing machine head, a presser foot rod vertically movement under the action of the spring 22. However, slidably and rotatably mounted in said structure, a radial outwardly extending pin fmounted 'on said rod adjacent its inpperien'd, a vertical 'slot'formed in said structure parallel -toisaiti rod-and extending from the upper end of s aid-tstructure and in which said pin is slidably guided,

saictslot being so located that when said pin is therein s'afd rod will be inarotated 'positio'n such that the needle openingein the presser foot carried by'said rod will be alignedwith the needle, abutment meansfixed to said rod, spring means acting on saidabutmenttmeans and unging saidrodiin a downward 'directiomrodtlifting operatively associated with said abutment means and movable in an upward direction to lift said rod against a the iaetion of said sp'ringtme'ans, a presser foot rod controlzmembe'rt movably connected" to .said structure 1 and operativelyt associated with saidlifting means to move the same, means for maintaining said liftingtmea'ns and said rod in an:intermediate or: low 'liftedposition, and means for maintaining'said lifting means and said rod. in a maximumior highliftedposition, said slotbeing of: such length that said pin will be spaced above a'lower. end of said slot when said rod is intits lowermost position and will be spaced above the upper end. of saidfslot and the upper end of said structure-when the rod is. in its high or maximum lifted position'wherebysaid rod can 'berotated.

6. Alpresser foot lifter mechanism as defined in claim 5 and wherein the upper end of said structure at the upper end. of said slot is provided with a flared cammingsur-t face adapted upon downward movement of said rod if engaged by saidpin to cam the latter into said slot and rotate said rod to a predetermined sewing position.

7. A ,presser foot lifter mechanism for asewing machine comprising a supporting structure forming part of t gaged with said teeth.

t a :8 r

the sewing :machine head, a presser'foot rod vertically slidably mounted in said structure,:-ahutment means fixed to said rodg-acoil'springfsurroundingsaid rod and atone end engaging said abutment means, an'abutment member forthe ot-her end of said springand movable on said rod mam-ma structure, means for adjustably moving said abutment mem'ber'and vsecuring it in adjusted position includingalever pivoted .at one end to said structure and operative'ly connected to saidabutment member and exending through a vertical slot; insaid structure, :rod lifting means operatively associated with said abutment means and movable in an upward :direction to lift said rod against theaactioniofi said spring means, a presserfoot rod controli'mem'benmovably connected 'to saidstructure and eperative'l'y associated with said lifting means tomove' the sameptmeans for-maintaining said lifting means and said and .in an intermediate or low wlifted position; iand means for maintainingsaid lifting means andzsaid rod in a maximum or high lifted position. a

[3. A'ipresser foot lifter mechanism asdefinedin' claim 7 and'wherein said slot has a'sidej wall provided with ratchet teeth, while said lever isso formed and mounted as nor-' mmly biasing laterally toward saidtratchet teeth "andtis provided with a fixed pawl adapted to be selectively en- References Cited in theifile of this patent UNITED STATES PATENTS Wendell Oct.l1'6,'1883 Toskey et al. Dec. '6, 1938

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