WORK FEEDING MEANS FOR SEWING MACHINES
United States Patent 3665877
For enabling a presser foot more effectively to cooperate with work feeding means such as a conventional dog, an auxiliary presser engageable with the presser foot is automatically actuated, at least for an initial portion of a sewing run, to cause the work to be uniformly fed to the needle of a sewing machine. The auxiliary pressure is attachable to most sewing machines and, while operable on single ply work, is likely to have particular advantage in feeding irregular or bulky items such as hems, binding, trimming or the like.
US Patent References:
Sewing machine presser foot
Silberman - October 1961 - 3002477
Auxiliary device for zig-zag sewing machines
Isler - March 1960 - 2926621
Presser foot for sewing buttonholes
Laidig - February 1967 - 3304896
Sewing machine presser foot
Silberman - October 1961 - 3002477
Auxiliary device for zig-zag sewing machines
Isler - March 1960 - 2926621
Presser foot for sewing buttonholes
Laidig - February 1967 - 3304896
Inventors:
Wickers, Francis A. (Beverly, MA)
France, David W. (West Newbury, MA)
Mason, Ronald C. (Hamilton, MA)
France, David W. (West Newbury, MA)
Mason, Ronald C. (Hamilton, MA)
Application Number:
05/071647
Publication Date:
05/30/1972
Filing Date:
09/14/1970
View Patent Images:
Export Citation:
Assignee:
USM Corporation (Boston, MA)
Primary Class:
International Classes:
D05B27/04; D05B27/00; D05B29/00
Field of Search:
112/212,235,236,240
Primary Examiner:
Lawson, Patrick D.
Claims:
Having thus described our invention, what we claim as new and desire to secure by Letters Patent of the United States is
1. In a sewing machine having stitch forming instrumentalities and work feeding mechanism for advancing a work piece over a work support to the operating zone of said instrumentalities, the feeding mechanism including two cooperative work-engaging members one of which is yieldingly movable to urge the work into clamping relation with the other member, the improvement which comprises a presser engageable with the yieldingly movable member to urge it more firmly toward the other member, and means for more intensively operating the presser during at least an initial interval as the work is fed between the members thereby increasing the effectiveness of the feeding mechanism.
2. A sewing machine as set forth in claim 1 wherein said cooperative members are an orbital feed dog and a presser foot, and said presser is in the form of a fluid pressure operated piston rod engageable with the presser foot.
3. A machine as set forth in claim 2 wherein the presser foot is carried by a downwardly urged bar, and a cylinder for actuating the piston rod is adjustably connected to said bar to enable a selected portion of the presser foot to be engaged by the piston rod.
4. A machine as set forth in claim 1 wherein a control circuit operable to start the machine includes a timing unit for maintaining the presser in engagement with the presser foot for a predetermined interval only of the feeding.
5. In combination with a sewing machine having a reciprocable needle, a bed, and work feeding means including a feed dog and cooperative presser foot for feeding the work on the bed to and through the stitching zone of the needle, said presser foot being pivotally mounted on a bar yieldingly urged toward the bed and having spring means for urging the presser foot toe portion upwardly from the bed, hemming means mounted to receive and form a margin of the work disposed ahead of the needle, a presser finger engageable with the presser foot toe portion, and a control circuit for starting the machine and actuating said presser finger when the hem has been formed whereby the presser finger enables the feeding means to advance the hem parallel to its marginal edge and toward said zone.
1. In a sewing machine having stitch forming instrumentalities and work feeding mechanism for advancing a work piece over a work support to the operating zone of said instrumentalities, the feeding mechanism including two cooperative work-engaging members one of which is yieldingly movable to urge the work into clamping relation with the other member, the improvement which comprises a presser engageable with the yieldingly movable member to urge it more firmly toward the other member, and means for more intensively operating the presser during at least an initial interval as the work is fed between the members thereby increasing the effectiveness of the feeding mechanism.
2. A sewing machine as set forth in claim 1 wherein said cooperative members are an orbital feed dog and a presser foot, and said presser is in the form of a fluid pressure operated piston rod engageable with the presser foot.
3. A machine as set forth in claim 2 wherein the presser foot is carried by a downwardly urged bar, and a cylinder for actuating the piston rod is adjustably connected to said bar to enable a selected portion of the presser foot to be engaged by the piston rod.
4. A machine as set forth in claim 1 wherein a control circuit operable to start the machine includes a timing unit for maintaining the presser in engagement with the presser foot for a predetermined interval only of the feeding.
5. In combination with a sewing machine having a reciprocable needle, a bed, and work feeding means including a feed dog and cooperative presser foot for feeding the work on the bed to and through the stitching zone of the needle, said presser foot being pivotally mounted on a bar yieldingly urged toward the bed and having spring means for urging the presser foot toe portion upwardly from the bed, hemming means mounted to receive and form a margin of the work disposed ahead of the needle, a presser finger engageable with the presser foot toe portion, and a control circuit for starting the machine and actuating said presser finger when the hem has been formed whereby the presser finger enables the feeding means to advance the hem parallel to its marginal edge and toward said zone.
Description:
BACKGROUND OF THE INVENTION
As a work piece is first advanced from an initial relatively static position toward the sewing instrumentalities of a sewing machine, it is likely to require the application of more feeding force than subsequently when a remaining length is to be fed and feeding is in progress. More especially, it is found that hard or bulky work to be sewn, such as hems or binding comprising more than a single ply, require a more positive feeding force to be applied when the work first reaches a stitching locality. In the absence of a means to enable a conventional presser foot and feed dog to effectively cooperate, the work may remain stationary and/or it may be unduly stretched or otherwise deformed before the desired uniform rate of feeding is attained.
In some sewing machines of the prior art the problem of uniformly feeding the upper and lower ply simultaneously has been met to some extent, for example, by the provision of an upper as well as a lower serrated feed dog and a presser foot. This involves employing complicated actuating mechanism in a rather crowded operating area, and entails application of positive feeding force when that may be unnecessary, or the continuous exertion of greater presser foot drag than may be desirable.
SUMMARY OF THE INVENTION
In view of the foregoing it is an object of this invention to provide an improved automatic work advancing mechanism for a sewing machine or the like. More particularly it is an object of this invention to provide a versatile device in a sewing machine for increasing the effectiveness of its feed mechanism, for example, a feed dog in at least a starting portion of each run.
Another object of the invention is to provide, in a sewing machine having a four-motion feed dog and a cooperative presser foot, an improved means for automatically urging the presser foot and the feed dog into closer relation as the first 1 or 2 inches of a workpiece are advanced past a needle.
To these ends, and in accordance with a feature of the invention, there is provided in a sewing machine, in combination with a pivotal presser foot and cooperative feed means such as an orbital feed dog, a presser finger engageable automatically with the presser foot for a predetermined interval to insure that the feed dog can effectively exert force to commence advancement of the work piece to be sewn. As herein shown the feed finger preferably is in the form of a rubber tipped piston rod adjustably mounted for engagement with a selected upper portion of a presser foot, the latter being yieldingly urged downwardly and being acted on by a spring for tilting the heel of the foot into initial bed engaging relation while its toe portion is inclined upwardly to permit reception of the edge of the work piece to be fed. Also, as herein shown, a control circuit including sensing means is employed for automatically starting the sewing machine and applying the auxiliary presser finger to urge the feed dog downwardly into substantially parallel relation to the bed of the machine during a first portion of the sewing run.
BRIEF DESCRIPTION OF THE DRAWINGS
The foregoing and other features of the invention will now be more particularly described in connection with an illustrative embodiment and with reference to the accompanying drawings thereof, in which:
FIG. 1 is a perspective view of a portion of a sewing machine adapted to perform hemming, a presser foot and auxiliary presser finger being in their raised or inoperative starting positions as a work piece is moved into a hemming device;
FIG. 2 is a schematic diagram of a control circuit provided for the machine of FIG. 1;
FIG. 3 is a perspective view similar to that of FIG. 1, on a larger scale, and showing the feeding means in operative relation to the work piece; and
FIG. 4 is an enlarged detail view in front elevation and partly in section showing a hem being fed.
Referring first to FIGS. 1, 3 and 4, a sewing machine generally designated 10 has a head 12 and a work supporting bed 14. The head is provided with stitch forming instrumentalities including a reciprocable needle 16. The machine further includes work feeding mechanism herein shown as a four-motion feed dog 18 operating in conventional manner in a slot in the bed 14 for cooperating cyclically with a presser foot 20. The latter is supported by a presser bar 22 which is reciprocable heightwise and yieldingly urged downwardly by means not shown. Preferably a compression spring 24 (FIG. 1) is disposed between a later mentioned bracket 26, adjustably secured by a clamp screw 28 to the bar 22, and a heel portion of the presser foot to yieldingly tilt its toe end 30 upwardly from the bed 14.
The bed 14 is provided, for purposes of this illustration, with a flat extension 32 fitted with one or more hemming devices 34, 36, but it will be understood that application of the invention is not thus limited but has general utility in more effectively feeding any flexible work pieces which, by reason of their hem, ornamentation, or other material characteristic, tend to provide added resistance to smooth, uniform feeding. A work piece W which is to have a hem H (FIG. 3) formed and then secured, as by stitching in the machine 10, may initially be introduced edgewise to the devices 34, 36 either manually or by an automatic feeder of the type which, for example, employs a reciprocable pick-off 38 shown in dash-lines in its delivery position in FIG. 1. The devices 34, 36 may also be hemmers of any suitable type including for instance those having a pneumatic in-feed and fully described in copending applications, Ser. No. 6,510, filed Jan. 28, 1970 in the name of Richard W. Gray, and Ser. No. 9,185, filed Feb. 6, 1970 in the name of Paul E. Morgan. It will be understood that the hemmers 34, 36 are aligned to provide a folded margin in the work parallel to the line of feed and stitching to be performed. A sensor 40 (FIGS. 1 and 2), which may be of any suitable type and is herein shown as fluidic, is disposed to straddle an orifice 42 formed in the extension 32. The arrangement desirably is such that introduction of the work to the hemmers 34, 36 intercepts a low pressure jet of air continuously flowing in the sensor 40 thereby, after a suitable interval allowed for hemming as determined by a time delay mechanism 44 (FIG. 2), signaling a fluid amplifier 46 which opens a valve 48 to allow pressure from a higher pressure line 50 to lower the bar 22 and the presser foot 20, first into tilted or heel engaging relation with the bed 14, as shown in full lines in FIG. 4, and then full bed engagement as indicated by dash lines. Though not here so shown, it will be understood that the control circuit being described also preferably acts simultaneously to initiate operation of the machine 10.
Fluid pressure line 52 (FIG. 2) from the fluid amplifier 46 also initiates a time delay unit 54 and actuates a valve 56 to allow fluid pressure to be admitted via a line 58 to a cylinder 60 (FIGS. 1-3) for operating an auxiliary, spring-return presser finger 62 next to be described. It may preliminarily be explained with reference to FIG. 3 that the left and now leading edge of the work W will, when first hemmed, lie between the feed dog 18 and the raised presser foot toe end 30. Hand presentation of the work to the hemmers, if employed, may also urge the leading work edge sufficiently leftward to enable it to come under the pulling influence of the presser foot and the feed dog, or the hemmers may be slightly angularly disposed when desirable to bias the left edge into the feeding zone of the dog 18. As the needle 16 and feed dog 18 commence operation it is desirable that the plies of the hem be uniformly advanced without slippage and that the considerable friction provided by the work folds in the hemmers 34, 36 be overcome positively. The presser finger 62, preferably fitted with a rubber tip 66 to avoid rebound, yieldably forces the presser foot into work-engaging position parallel with the bed 14, the underside of the presser foot at once causing the work to be gripped effectively and hence fed by the operation of the dog 18. The cylinder 60 is adjustably mounted to direct its piston rod, functioning as the presser finger 62 referred to, downwardly against any selected portion of the presser foot 20. For this purpose a bracket 64 (FIGS. 1 and 3) has a forked end adjustably clamped to the cylinder 60 and an opposite mounting end extending into, and adjustable about the horizontal axis of, a bore formed in the bracket 26.
After an initial interval of engagement of the presser foot tip 66 with the presser foot toe 30, usually sufficient to effect 1 or 2 inches of feeding, the unit 54 times out the finger 62 is retracted as pressure to the cylinder 60 is cut off by the valve 66. Normal feeding operation then proceeds until the hem H has been completely secured.
As a work piece is first advanced from an initial relatively static position toward the sewing instrumentalities of a sewing machine, it is likely to require the application of more feeding force than subsequently when a remaining length is to be fed and feeding is in progress. More especially, it is found that hard or bulky work to be sewn, such as hems or binding comprising more than a single ply, require a more positive feeding force to be applied when the work first reaches a stitching locality. In the absence of a means to enable a conventional presser foot and feed dog to effectively cooperate, the work may remain stationary and/or it may be unduly stretched or otherwise deformed before the desired uniform rate of feeding is attained.
In some sewing machines of the prior art the problem of uniformly feeding the upper and lower ply simultaneously has been met to some extent, for example, by the provision of an upper as well as a lower serrated feed dog and a presser foot. This involves employing complicated actuating mechanism in a rather crowded operating area, and entails application of positive feeding force when that may be unnecessary, or the continuous exertion of greater presser foot drag than may be desirable.
SUMMARY OF THE INVENTION
In view of the foregoing it is an object of this invention to provide an improved automatic work advancing mechanism for a sewing machine or the like. More particularly it is an object of this invention to provide a versatile device in a sewing machine for increasing the effectiveness of its feed mechanism, for example, a feed dog in at least a starting portion of each run.
Another object of the invention is to provide, in a sewing machine having a four-motion feed dog and a cooperative presser foot, an improved means for automatically urging the presser foot and the feed dog into closer relation as the first 1 or 2 inches of a workpiece are advanced past a needle.
To these ends, and in accordance with a feature of the invention, there is provided in a sewing machine, in combination with a pivotal presser foot and cooperative feed means such as an orbital feed dog, a presser finger engageable automatically with the presser foot for a predetermined interval to insure that the feed dog can effectively exert force to commence advancement of the work piece to be sewn. As herein shown the feed finger preferably is in the form of a rubber tipped piston rod adjustably mounted for engagement with a selected upper portion of a presser foot, the latter being yieldingly urged downwardly and being acted on by a spring for tilting the heel of the foot into initial bed engaging relation while its toe portion is inclined upwardly to permit reception of the edge of the work piece to be fed. Also, as herein shown, a control circuit including sensing means is employed for automatically starting the sewing machine and applying the auxiliary presser finger to urge the feed dog downwardly into substantially parallel relation to the bed of the machine during a first portion of the sewing run.
BRIEF DESCRIPTION OF THE DRAWINGS
The foregoing and other features of the invention will now be more particularly described in connection with an illustrative embodiment and with reference to the accompanying drawings thereof, in which:
FIG. 1 is a perspective view of a portion of a sewing machine adapted to perform hemming, a presser foot and auxiliary presser finger being in their raised or inoperative starting positions as a work piece is moved into a hemming device;
FIG. 2 is a schematic diagram of a control circuit provided for the machine of FIG. 1;
FIG. 3 is a perspective view similar to that of FIG. 1, on a larger scale, and showing the feeding means in operative relation to the work piece; and
FIG. 4 is an enlarged detail view in front elevation and partly in section showing a hem being fed.
Referring first to FIGS. 1, 3 and 4, a sewing machine generally designated 10 has a head 12 and a work supporting bed 14. The head is provided with stitch forming instrumentalities including a reciprocable needle 16. The machine further includes work feeding mechanism herein shown as a four-motion feed dog 18 operating in conventional manner in a slot in the bed 14 for cooperating cyclically with a presser foot 20. The latter is supported by a presser bar 22 which is reciprocable heightwise and yieldingly urged downwardly by means not shown. Preferably a compression spring 24 (FIG. 1) is disposed between a later mentioned bracket 26, adjustably secured by a clamp screw 28 to the bar 22, and a heel portion of the presser foot to yieldingly tilt its toe end 30 upwardly from the bed 14.
The bed 14 is provided, for purposes of this illustration, with a flat extension 32 fitted with one or more hemming devices 34, 36, but it will be understood that application of the invention is not thus limited but has general utility in more effectively feeding any flexible work pieces which, by reason of their hem, ornamentation, or other material characteristic, tend to provide added resistance to smooth, uniform feeding. A work piece W which is to have a hem H (FIG. 3) formed and then secured, as by stitching in the machine 10, may initially be introduced edgewise to the devices 34, 36 either manually or by an automatic feeder of the type which, for example, employs a reciprocable pick-off 38 shown in dash-lines in its delivery position in FIG. 1. The devices 34, 36 may also be hemmers of any suitable type including for instance those having a pneumatic in-feed and fully described in copending applications, Ser. No. 6,510, filed Jan. 28, 1970 in the name of Richard W. Gray, and Ser. No. 9,185, filed Feb. 6, 1970 in the name of Paul E. Morgan. It will be understood that the hemmers 34, 36 are aligned to provide a folded margin in the work parallel to the line of feed and stitching to be performed. A sensor 40 (FIGS. 1 and 2), which may be of any suitable type and is herein shown as fluidic, is disposed to straddle an orifice 42 formed in the extension 32. The arrangement desirably is such that introduction of the work to the hemmers 34, 36 intercepts a low pressure jet of air continuously flowing in the sensor 40 thereby, after a suitable interval allowed for hemming as determined by a time delay mechanism 44 (FIG. 2), signaling a fluid amplifier 46 which opens a valve 48 to allow pressure from a higher pressure line 50 to lower the bar 22 and the presser foot 20, first into tilted or heel engaging relation with the bed 14, as shown in full lines in FIG. 4, and then full bed engagement as indicated by dash lines. Though not here so shown, it will be understood that the control circuit being described also preferably acts simultaneously to initiate operation of the machine 10.
Fluid pressure line 52 (FIG. 2) from the fluid amplifier 46 also initiates a time delay unit 54 and actuates a valve 56 to allow fluid pressure to be admitted via a line 58 to a cylinder 60 (FIGS. 1-3) for operating an auxiliary, spring-return presser finger 62 next to be described. It may preliminarily be explained with reference to FIG. 3 that the left and now leading edge of the work W will, when first hemmed, lie between the feed dog 18 and the raised presser foot toe end 30. Hand presentation of the work to the hemmers, if employed, may also urge the leading work edge sufficiently leftward to enable it to come under the pulling influence of the presser foot and the feed dog, or the hemmers may be slightly angularly disposed when desirable to bias the left edge into the feeding zone of the dog 18. As the needle 16 and feed dog 18 commence operation it is desirable that the plies of the hem be uniformly advanced without slippage and that the considerable friction provided by the work folds in the hemmers 34, 36 be overcome positively. The presser finger 62, preferably fitted with a rubber tip 66 to avoid rebound, yieldably forces the presser foot into work-engaging position parallel with the bed 14, the underside of the presser foot at once causing the work to be gripped effectively and hence fed by the operation of the dog 18. The cylinder 60 is adjustably mounted to direct its piston rod, functioning as the presser finger 62 referred to, downwardly against any selected portion of the presser foot 20. For this purpose a bracket 64 (FIGS. 1 and 3) has a forked end adjustably clamped to the cylinder 60 and an opposite mounting end extending into, and adjustable about the horizontal axis of, a bore formed in the bracket 26.
After an initial interval of engagement of the presser foot tip 66 with the presser foot toe 30, usually sufficient to effect 1 or 2 inches of feeding, the unit 54 times out the finger 62 is retracted as pressure to the cylinder 60 is cut off by the valve 66. Normal feeding operation then proceeds until the hem H has been completely secured.