US3540391A

US3540391A - Work feeding mechanism

Info

Publication number: US3540391A
Application number: US812105A
Authority: US
Inventors: Robert A Hayes
Original assignee: Union Special Machine Co
Current assignee: Union Special Machine Co
Priority date: 1969-04-01
Filing date: 1969-04-01
Publication date: 1970-11-17
Anticipated expiration: 1987-11-17
Also published as: GB1298106A

Description

United States Patent [72] inventor Robert A. l-hye Primary Examiner-Richard J. Scanian,.lr. Franklin Park, Illinois Anorney1-1.C.Dieserud [2i] AppLNo. 812,105 I [22] Filed April l, 1969 I [45] Patented Nov. 17, 1970 ABSTRhCT: A sewing machine having work feeding (73] Assignee Union Special Machine Company mechanism adapted to engage the work on its upper and Chicago, Illinois under surfaces to insure advancing the work to the desired exacorporation oflllinois tent in the'course of a stitching operation. it is particularly concerned with sewing machines normally having only one rotary drive shaft which is disposed in the base portion of the machine, beneath the surface along which the work being stitchedis advanced. The invention involves the provision of a [54] second rotary shaft at only a slight distance above the Work y 8 g supporting surface. The usual connections are provided from 1112/212 the drive shaft to a feed dog below the work supporting sur- Dosh 27/04 face and special connections are also provided to a feed dog [50] 112/212, above the work supporting surface from said second rotary v 207 shaft. The mechanism for accom iishing this is of minimum P weight and both feed dogs are lifted and lowered and also [56] References cited reciprocated in the direction of feed and then returned in the UNITED TATE PATENTS opposite direction by relatively short and direct connections 814,026 3/1906 Dearborn .Q 112/212 from the rotary shafts mentioned. This enables operation of 3,099,974 8/1963 Chudner.... 112/207 both the 'top and bottom feed dogs at exceptionally high 3,162,158 12/1964 Chudner 1 12/207 speeds, with a minimum of vibration being created.

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- it i 1 2 Patented Nov. 17, 1970 h 7 3,540,391

Sheet 2 of 7 Patented Nov. 17, 1970 3,540,391

Sheet 4 of? Patented Nov. 17, 1970 3,540,391

Sheet 5 of 7 Patented Nov. 17, 1970 3,540,391

Sheet 7 of? I WORK FEEDING MECHANISM This invention relates to work feeding mechanism provided in a high speed sewing machine. It is of a character involving feed dogs cooperating with both the top surface and the under surface of a workpiece to insure accurate advance of the latter step-by-step through the stitch-forming zone of the machine.

An object of the invention has been to provide both top and bottom work feeding mechanisms operated in coordination for insuring the uniform step-by-step advance of multiplelayered workpieces through the stitching zone. As is well'understood, there are certain types of workpieces which require the gripping of the same on both their top and bottom surfaces in order to insure proper advance of the workpieces through the stitching zone with no slippage of one layer in relation to another. Typical instances of this are the performance of stitching operations on gloves or the like for closing the same, or attaching binding strips, or performing edge stitching operations on the same. A-particular problem which the invention deals with most effectively involves two or more layers of material forming the workpiece which have cooperating surfaces that are quite smooth and are readily slidable in relation to each other as they are advancedthrough the stitching zone in the course of high speed operation of the machine.

The present invention provides work feeding mechanism both above and below the workpiece, each of these feeding mechanisms being directly operated from a related rotary shaft in a manner to insure uniform operation of the two work feeding mechanisms at high speeds with a minimal tendency to produce objectionable vibrations in the machine.

With the foregoing objects, features and advantages of the invention in mind certain embodiments of the same will now be described in detail by reference to the accompanying drawings, in which:

FIG. 1 is a longitudinal, vertical sectional view through a flat bed machine having a main drive shaft in the base, and which embodies one form of the novel connections from said shaft to the top work feeding mechanism;

FIG. 2 is an end view of the machine shown in FIG. 1, as seen from the left of FIG. I, a cover member being removed and portions of the frame being broken away to illustrate the mechanism within the machine;

FIG. 3 is a plan view of a portion of the base of the machine with the work supporting member thereof removed and with certain parts broken away to more clearly illustrate the construction;

FIG. 4 is a vertical sectional view taken through the machine along the line 4-4 of FIG. 1;

FIG. 5 is an exploded perspective view of the top feed mechanism embodied in the machine;

FIG. 6 is a detail view, partly in elevation and partly in vertical section, showing certain parts of the top feed mechanism;

FIG. 7 is a front elevational view ofa modified form of the invention applied to a flatbed sewing machine; and

FIG. 8 is an end elevational view of a machine embodying the modified form of the invention.

The invention has been illustrated in the drawings as applied to a flat bed sewing machine, but it will be understood that it is capable of being applied to other types of sewing machines. The illustrated machine has a frame structure involving a bed portion 10, a vertical standard 11, an overhanging arm 12 and a head portion 13 at the outer end of said overhanging arm. Within the base portion of the machine there is provided a main drive shaft 14 which extends outwardly from the frame at the right side thereof (FIG. 1) and has secured thereto a combined handwheel and pulley 15. Through the latter the main drive shaft is adapted to be driven by a belt from any suitable power source. Within the vertical standard 11 of the frame, the shaft 14 is provided with a crank member 16, which, in a well-known manner, serves to impart movement to a pitman 17 which has its upper end connected with one end of a lever 18 rockably mounted on a shaft or stud 19. The other end of lever 18, at the left in FIG. 1, is connected with a needle bar 20 which is mounted for vertical reciprocation within the head 13 in a conventional manner. At its lower end the needle bar carries a needle 21 which is reciprocated from a position above the work supporting surface of the machine 'to a position in which its threaded eye is below said surface. As shown in FIGS. 1 and 2 the bed portion of the frame is provided with a conventional work supporting plate 10a secured to a top plate 10b extending over substantial portions of the top of the bed of the frame. The stitch forming mechanism may be of any of the conventional forms adapted to provide a suitable line of stitching. That illustrated in the drawing includes a four-motion looper 22 which cooperates with the needle, when the latter extends downwardly through the work, to form a two-thread chain stitch, type 401. Other devices are provided for insuring the proper cooperation of the stitchforming elements, but these are of conventional form and mode of operation, so that they need not be described. Suffice it to say that the looper is rockably mounted on a sleeve 23a which in turn is mounted on a shaft 23, and is adapted for rocking movement about the axis of that shaft for needle avoid purposes. The rocking of the looper with respect to said sleeve imparts the loop seizing and shedding movements to the looper. For imparting such movements to the looper there is provided a link 24 which is connected with the rockable looper at one end and with connections from the drive shaft at its other end. These connections include a rock member 25 and a pitman 26 which is connected at one end with an eccentric on the drive shaft and at its other end with an arm of the rock member.

Within the base portion of the machine there is provided a conventional form of work feeding mechanism which is best shown in FIG. 4. It comprises a feed dog 27 which is adjustably mounted upon a member 28 which is pivotally connected with a shaft or stud 29 carried by the upper portion of a feed rocker member 30. A downwardly extending portion 28a of member 28 has its right end pivotally connected with a pitman 34, the upper end of which surrounds an eccentric 35. Lifting and lowering movements are imparted to the feed dog 27 by this eccentric. Rocking movements are imparted to the feed rocker 30 by the connections shown in FIG. 2. These include an arm 31 secured to a stud 30a extending laterally from a part ofthe rocker 30. At its free end, the arm 31 is connected with a pitman 32, the upper end of which cooperates with an adjustable eccentric 33. Conventional means may be provided for varying the extent of eccentricity of eccentric 33 so as to bring about the desired feed stroke of the feed dog 27.

The present invention is primarily concerned with a special novel mechanism for imparting a feed movement to the top portion of the work in cooperation with the under feed dog 27. As has been indicated, it has frequently been found necessary or desirable to impart a feeding movement to the top layer of a multiple layer workpiece being advanced through the stitch forming zone. By the present invention such top feeding action is provided in such a way as to eliminate undue noise and vibration, with the machine being capable of operation at very high speeds.'To achieve this end it has been found highly desirable to provide a separate drive shaft 36, above the work supporting plate 10a Shaft 36 must, of course, be driven in timed relation with the main drive shaft 14. For this purpose there is secured a toothed pulley wheel 37 to the shaft 36 at a point intermediate two

upstanding members

10c and 10d integral with or otherwise secured to the top 10b of the base of the frame. The pulley 37 is connected by a toothed belt 38 with a toothed pulley 39 secured to the main drive shaft 14. The arrangement is such that for each revolution of the main drive shaft a revolution will be imparted to the special drive shaft 36.

Secured to the rear side of the head of the overhanging arm of the machine is a special bracket 40, the form of which is best shown in FIG. 5. On its rear side, this bracket has an extension 40a secured to it by screws 400 shown in FIG. 2. ,The bracket itself is secured by screws 40b to the head of the machine frame. Within the partially enclosed space formed by the four downward projections 40d of the bracket 40 there is slidably mounted an inverted U-shaped bracket 41. This has extending through it, adjacent its upper end, a flat spring bar 42, one end of which is snugly fitted between pins 43 carried by bracket extension 40a and at its opposite end it fits snugly between pins 44 carried by a flattened, downward extension 45a of a presser bar member 45. The latter is normally urged downwardly by a spring 46 which surrounds the upper end of the presser bar and exerts a force against a collar 45b secured to the presser bar. The upper end of the spring 46 surrounds a downwardly extending pin 47 having a knurled head 47a at its upper end. This permits adjustment of the force exerted by the spring 46 against the collar 45b and hence the presser bar 45. It may be mentioned that the present construction is such as to bring about proper operation of the presser foot, to be described, with a smaller force being exerted by the spring 46 than is required in a conventional presser foot structure. The bracket 41 has a curved surface 41b provided on the underside of the top of the inverted U, as best shown in FIG. 2, to facilitate the desired flexing of the spring bar 42 during the operation of the machine. A pin 41a extending beneath the spring bar 42 serves to retain the latter against the curved surface 41b. Adjacent the lower ends of the downwardly extending arms of the bracket 41, openings 410 are provided for the reception ofa pin to be later described.

As best shown in FIGS. 1 and 5, the top feed assembly includes a substantially horizontally disposed presser bar 48, the downwardly and outwardly extending end 48d of which is adapted to engage the work applied to the top of the cloth plate 10a. Alongside of the presser bar 48 is a top feed bar 50 which has one face cooperating in slidable relation with the adjacent face of the presser bar. To minimize the frictional re sistance to the relative movement of these parts, the presser bar is provided with a cutout area 48a in its midportion, and to reduce the weight of the presser bar and the feed bar they are both provided with relatively large openings in their midregions. To the forward end of the feed bar there is attached a toothed member 50a which is adapted to engage the top surface of the work to be stitched.

in FIG. the various parts embodied in the top feed mechanism and presser foot assembly are shown in spaced relation to facilitate a disclosure of the form and relationship of the various elements. The shaft 36 is provided with an eccentric portion 36a, the axis of which is disposed a suitable distance above the axis of the main body of the shaft 36. A threaded portion 36b extends outwardly from the eccentric portion 36a. A washer 53b is mounted on the extension 36a of the shaft and is retained against the shoulder 36d by the other parts to be described. A slide element 49 is mounted between the forked portions 480 of the presser bar 48, and this slide element is mounted on the extension 36a of shaft 36. Accordingly, it will be clear that upon the rotation of the shaft 36 the element 49 and the forked end 480 of the presser bar will be lifted and lowered and the element 49 will also be shifted longitudinally of the passage provided between the forked extensions 480. The top feed bar 50 is then mounted along the side of the presser bar and the slide member 49, so as to provide an opening 50b in alignment with the extension 36a of the shaft 36. Within the opening 50b of the feed bar 50 there is mounted an eccentric 51 having an opening 51a adapted to fit snugly around the extension 36a of the shaft. A key 360 cooperating with a slot 36e (FlG. 6) in the extension 36a and also fitted in a notch 51b in the eccentric element 51 serves to retain the latter in a fixed angular relation to the axis of the shaft 36. The element 51 provides a cylindrical peripheral surface which has its axis disposed in the opposite direction from the axis of shaft 36 than is the axis of the extension 36a Accordingly, at any instant in the course of revolution of the shaft 36 the element 49 and cooperating portion of the pressure bar will be displaced from their normal or central positions in one direction from the axis of shaft 36, while the eccentric element 51 and the cooperating portion of feed bar 50 will be displaced in the opposite direction from the axis of shaft 36. Outwardly of the eccentric element 51 there is provided a disc 52 adapted to fit over the threaded extension 36b of the shaft, and it is provided with a groove 52a which receives and retains the element 36c. A washer element 530 is provided outwardly of the element 52, and a nut 54 then applied to the outer end of the threaded extension 36!) of the shaft serves to retain all of the parts described above in assembled relation. It will be understood that the presser bar 48 and the feed bar 50 are not clamped firmly together by the action of the nut 54 but are retained in close relationship with the ability to shift relative to each other.

The presser bar 48 and the feed bar 50 are further retained in assembled relation, but with the ability to shift in relation to each other by a pin 55. The latter passes through an opening in a small block 50d which is slidably mounted within a rectangular opening 500 in the feed bar. Pin 55 also passes through an opening 481; in the presser bar so as to maintain the latter against longitudinal shifting. However, it permits pivotal movement of the presser bar about the axis of the pin. The end portions of the pin pass through openings 410 in the legs of bracket 41.

Split washers

55c and 55d cooperating with

grooves

55a and 55b, respectively, serve to retain the pin 55 and the presser bar and feed bar and the bracket 41 in assembled relationship.

It will be seen from the foregoing that upon rotation of the shaft 36, the eccentric portion 36a will impart a lifting and lowering movement to the element 49 and hence to the rearward end of the presser bar. It will also impart some longitudinal movement to the element 49 within the forked extensions 480 of the presser bar. The lifting and lowering of element 49 causes rocking of the presser bar about the axis of the pin 55 to lift and lower the forwardly extending foot portion 48d of the presser bar, to carry this away from and then downwardly against the work on the support 100. On the other hand, the feed bar 40 is not only rocked about the axis of the pin 55 by the action of the eccentric 51, but is also shifted back and forth by the action of that eccentric. such shifting is, of course, permitted by the cooperation of the element 50d with the rectangular opening 500 in the feed bar.

Summarizing the foregoing, the

eccentrics

36a and 51 will impart certain movements to the presser bar, the feed bar, and related parts to bring about a reliable step-by-step feeding movement of the workpiece being stitched. At the time in a cycle of operation of the machine in which the eccentric 51 is in the position shown in FIG. 2, the feed dog has been lifted away from the work, while at the same time the eccentric 36a has rocked the presser bar into the position in which the end 48d thereof engages the work. This will be at a time beginning prior to that in which the feed bar is returned toward the right (FIG. 2) to prepare it for its next feed stroke. It will be appreciated that during the same time the eccentric 36a will have imparted a lifting movement to the slide member 49 and hence the rearward end of the presser bar, while the foot portion 48d will have remained in engagement with the work. During this time the bracket 41 will be lifted to a certain extent by the action of the pin 55, so that the presser foot 48d will remain engaged with the work under the action of the spring 46 and the spring bar 42. However, when the eccentric 51 revolves into a position in which the feed dog is brought into engagement with the work, the eccentric 36a will lift the presser foot away from the work and the continued rotation of the eccentric 51 will then cause the feed dog to impart a feed movement to the work. Either the presser foot or the feed dog will thus be engaged with the work during all portions of a revolution of the main shaft in the normal operation of the machine.

One advantage of the construction described above is that is enables the ready substitution of various eccentrics for the one designated 51. The substitution of a different eccentric disc for the one embodied in the machine at a particular time will enable changing the feed stroke of the upper feed dog to substantially coincide with the feed stroke of the lower feed dog which, as has been explained above, may be varied by adjusting the eccentric 33 of FIG. 2.

Suitable means may be provided for lifting the presser foot under manual control. as by the operation of a knee press member or a foot treadle. This, of course, is desirable to facilitate the removal and introduction of workpieces. As shown in FIG. 2, a rod 56 extending from a knee press or foot treadle cooperates with a lever 57 secured toa shaft or stud 58 (FIG. 1) extending into the upper end of the vertical standard of the machine frame. A member 59 secured to the inner end of this shaft or stud is connected by a rod 60 with a bell crank lever 61 secured by a shoulder screw 62 to a wall of the overhanging arm 12 of the frame. A spring 63 normally urges the lever 61 in a counterclockwise direction (FIG. 1), but when a knee press or foot treadle is operated to exert a pull on the rod 60, the lever 61 will act through a connection 64 (FIG. 2) to the presser bar 45 which will then be lifted and will cause the lifting of the U-shaped member 41, and then also both the presser foot and the top feed dog.

The foregoing embodiment of the invention has been shown as applied to a machine in which the stitching operation is to be performed along a line at or close to the righthand edge of the work as the latter is being fed into and through the machine. In FIGS. 7 and 8, the invention is shown as applied to a machine in which the stitching operation may be performed at a substantial distance inwardly from righthand edge of the work being fed to and through the stitching zone of the machine. The construction of this embodiment of the inven tion is substantially the same as that described above in many respects. It comprises a main drive shaft 14 having a combined handwheel and pulley attached to the end thereof which extends outwardly from the base of the machine frame. A crank 16 is provided on this shaft and is arranged to operated a pitman 17 which will drive the needle bar in the manner explained. So also the shaft 14 is arranged to drive a four-motion looper 22 in the manner explained above. Within the base of the machine and in the vertical standard thereof, there is a different type of connection to a shaft 65 which serves to drive the top feed dog which may be of same character as that designated 50a in the embodiment of FIG. 2. The shaft 65.'is suitably journaled in bearings mounted in the vertical standard 11 of the frame and also in a bracket 71 which is secured to the head 13 of the overhanging arm, and which extends downwardly to a point slightly above the top plate 10a of the base of the machine frame. Within the vertical standard of the frame there are secured to the shaft 65 two

collars

69 and 70. These cooperate with the bushings which support the shaft 65 within the vertical standard, and they serve to retain the shaft against any substantial axial movement.

The connections for driving the shaft 65 include a toothed pulley 66, secured to that shaft adjacent the collar 70, a toothed belt 67, and a toothed pulley 68 secured to the main drive shaft 14. This arrangement is such as to drive the shaft 65 at the same speed as the shaft 14.

The rest of the embodiment of the invention shown in FIGS. 7 and 8 may suitably be of substantially the same form-as that illustrated and described in connection with FIGS. 1-6, inclusive. As will be apparent from FIG. 7, the main advantage of the modified construction of the machine is that it permits the top feed mechanism to be utilized in connection with stitching operations performed at a substantial distance from the right edge of the work. In fact, the stitching operations may be performed at any distance from the right edge of the work, since if necessary a portion of the latter may be folded over in a way to permit it to be pushed under the shaft 65.

It has been found that the construction and arrangement of the presser bar and the feed bar and related parts, in accordance with the invention as disclosed, enables the use of a smaller initial spring pressure to be exerted by the coil spring 46 than is conventionally required to insure proper handling of the work being stitched. This has reduced the amount of effort required by the operator to bring about lifting of the presser foot, for the introduction and removal of the work.

While two preferred embodiments of the invention have been described in considerable detail, it will be understood that various changes may be made in the particular form of the top feed mechanism, and also the bottom fed feed mechanism. as well as the stitch forming mechanism and the like, within the scope of the invention, as defined by the appended claims.

Iclaim:

1. In a high speed sewing machine having a work supporting surface along which multilayered workpieces may be advanced, work retaining and advancing means which comprises a presser foot adapted to engage the top surface of the work being stitched and urge the latter against said work supporting surface, a four motion feed dog arranged to engage the top surface of the work in a region adjacent said presser foot. a drive shaft arranged above and parallel with said work supporting surface, and connections from said drive shaft for operating said feed dog and for lifting said presser foot periodically, said connections including eccentric surfaces carried by said shaft, one of said eccentric surfaces being adapted to cause lifting of said presser foot and another of said eccentric surfaces being substantially simultaneously adapted to lower said feed dog into engagement with the work and to then impart a longitudinal movement to said feed dog to advance the work.

2. In a sewing machine as set forthin claim 1, said presser foot and said feed dog being mounted on substantially horizontally disposed and longitudinally movable bars.

3. In a sewing machine as set forth in claim 2, said bar on which said feed dog is mounted having a circular opening which cooperates with the other of said eccentric surfaces on said shaft.

4. In a sewing machine as set forth in claim 2, said bar on which said feed dog is mounted having one end thereof surrounding said other of the eccentric surfaces on said shaft, and means carried by said bar intermediate the ends thereof adapted for slidable and pivotal movement relative to said bar, said means being mounted for movement in only a direction substantially perpendicular to said work supporting surface, and spring means normally urging said slidable means and the free end of said bar toward said work supporting surface.

5. In a sewing machine as set forth in claim 4, a guide member fixedly mounted on the frame of the machine, said means carried by said bar cooperating with said guide member for vertical movement in relation thereto.

6. In a sewing machine as set forth in claim 4, said eccentric surfaces and said spring means cooperating with said presser foot and feed dog bars to retain the presser foot and the feed dog alternately engaged with the work during operation of the machine.

7. In a sewing machine as set forth in claim 5, said spring means comprising a flat spring bar, said means carried by said bar on which the feed dog is mounted comprising an inverted U-shaped member adapted to receive and retain a portion of said spring bar in a manner to enable ready bending of said spring bar in the region in which it is so retained.

8. In a sewing machine as set forth in claim 7, said inverted U-shaped member having its downwardly extending portions cooperating slidingly with the outer faces of said bars on which said presser foot and said feed dogs are mounted.

9. In a sewing machine as set forth in claim 7, a pin extend ing between the downwardly extending portions of said U- shaped member, said presser foot carrying bar having an opening closely surrounding said pin, and said feed dog carry ing bar being slidably connected with said pin.

10. In a sewing machine as set forth in claim 2, said bar which carries the presser foot having a floating pivotal connection at its rear end, and said bar which carries the feed dog having a floating pivotal connection adjacent its forward end.

11. In a sewing machine as set forth in claim 1, a main drive shaft mounted in the frame of the machine below the work supporting surface, a toothed pulley secured to each of the two drive shafts mentioned, and a toothed belt interconnecting said toothed pulleys for driving the same in unison at the same speed.

8 machine having a frame comprising a base portion, a vertical standard portion and an overhanging arm said toothed pulleys and said belt being disposed in said vertical standard portion of said frame.

UNITED 'STATES PATENT OFFICE CERTIFICATE OF CORRECTION Patent No. 3; 5 39 Dated May 97 Inventor(s) Robert Hayes It is certified that error appears in the above-identified patent and that said Letters Patent are hereby corrected as shown below:

On the first page, first line, containin the general ininformation, the inventor's name Robert A. Haye" should be Robert A. Hayes Col. 5, line 32, "operated" should be operate Signed and sealed this 11 th day of September 1 971 (SEAL) Attest:

EDWARD M.FLETCHER, JR.

ROBERT GOTTSCHALK Attesting f i Acting Commissioner of Patem Col. 5, line 25, insert the word the before "righthand";