US2899920A

US2899920A - Sewing machine feeding mechanisms

Info

Publication number: US2899920A
Authority: US
Publication date: 1959-08-18
Anticipated expiration: 1976-08-18

Description

E. F. DUNN SEWING MACHINE FEEDING MECHANISMS Aug. 18, 1959 Filed Oct. 17, 1957 2 Sheets-Sheet l O n 3 I 3 a R i m D Q m 5 m F l W E 4 G om 1 a I. 4 E F. m mm B nw 3 Q i I 7 F 2 H w w 3 4 Q {w m m 5 I L, m 2 h\m 2 8 F m I l7\ ii 37 WITNESS M W A TTORNEY E. F. DUNN SEWING MACHINE FEEDING MECHANISMS Aug. 18, 1959 2 Sheets-Sheet 2 Filed Oct. 17, 1957 INVENTOR. Earl F Dunn WITNESS 2,899,920 SEWING MACHINE FEEDING MECHANISMS Earl F. Dunn, Monroe, Conn., assignor to The Singer Manufacturing Company, Elizabeth, NJ., a corporation of New Jersey Application October 17, 1957, Serial No. 691,524 10 Claims. (Cl. 112-410) This invention relates to sewing machines and more particularly to a work manipulating instru mentality such as a four motion feeding mechanism adapted to advance work across the stitching mechanism of a sewing machine employing a free cylindrical work arm.

This application is a continuation-in-part of my United States patent application, Serial No. 63 8,005, filed February 4, 1957, which is now abandoned.

In sewing machines of the free arm type it is essential, because of the limited work supporting surface, that the usual serrated feed teeth of the feeding element be maintained in a substantially horizontal plane during the feed advance movement of the feeding mechanism in order that the work be uniformly stitched. In order to accomplish this result there is usually employed a feeding mechanism including a horizontally movable feed bar carrier and a feeding element slidably carried by the feed bar carrier for movement in a Vertical plane. The feed bar carrier and the feeding element are each separately actuated in timed relation with each other and are arranged such that the vertically movable feeding element partakes of the horizontal movement of the feed bar carrier thereby to define a substantially rectilinear path typical of a four motion feed.

It is an object of the present invention to provide new and improved feeding mechanism and in particular a simple and readily adjustable guiding arrangement on the feed bar carrier for carrying and maintaining the serrated feeding surface of the feeding element in a horizontal position as the feeding element is raised to a work engaging position during the feed advance movement of the carrier.

With the above and other objects in view, as will hereinafter appear, the invention comprises the devices, combinations and arrangements of parts hereinafter described in connection with the accompanying drawings which illustrate a preferred embodiment of the invention and advantages attained thereby will be readily understood by those skilled in the art.

In the drawings:

Fig. 1 is an end view in elevation of a sewing machine work arm with theusual work arm cover plate removed and including one embodiment of the feeding mechanism of the present invention.

Fig. 2 isa top cross sectional view of the sewing machine work arm illustrated in Fig. 1, showing the feeding mechanism.

Fig. 3 is a cross sectional view taken substantially along the line 33 of Fig. 1 showing the details of the stud connecting the feed bar carrier to the rock shaft.

Fig. 4 is a front elevation view of the feeding mechanism.

Fig. 5 is an end view in elevation of a second embodiment of the invention.

Fig. 6 is a cross sectional view taken substantially along the line 66 of Fig. 5 showing the details of the means for selectively positioning the feed bar gib on the feed bar carrier and the means for securing the carrier to the rock shaft.

Referring to the drawings, the present invention is embodied in a sewing machine having a free cylindrical work arm 10 in which is journaled a rotary bed shaft 11 and a rock shaft 12. The bed shaft 11 and rock shaft 12 are driven in a manner conventional to the four motion feed mechanism of the type herein to be described. For a more detailed description of a typical driving arrangement reference is made to the feed driving mechanism disclosed in United States patent to Dimond et al., No. 604,005, May 10, 1898. Since the present invention relates primarily to the feed mechanism structure and not to the means for driving it, it is not believed that a more detailed description is necessary.

Secured on the shaft 11 adjacent the free end thereof is a feed actuating element in the form of an eccentric 13 which serves to impart feed lift movement to the feeding mechanism. Inwardly of the eccentric 13 there is mounted on the shaft a circular collar 14 having a peripheral goove 15 formed concentric with the shaft 11.

Carried on the collar 14 and seated within the peripheral groove 15 is a yoke 16 the limbs of which are horizontally disposed and embrace the upper and lower surfaces of the collar 14. Integral with and extending vertically upwardly from the yoke 16 is a feed bar carrier 17 having formed along one vertical edge thereof an undercut guiding surface 18 forming one side of a slideway 19 adapted to receive and guide a feed bar 20. The other side of the slideway 19 is formed by a gib 21 having an undercut surface 22 opposed to the surface 18. The gib 21 is adjustably secured to the feed bar carrier 17 in a manner such that its surface 22 can be set parallel to surface 18, thereby to prevent rocking movement of the feed bar 20 during its sliding movement in the slideway 19.

To accomplish the adjustable positioning of the gib 21, there is provided by the present invention an arrangement which permits the adjustment to be simply and accurately performed while at the same time assuring that the gib 21 will be securely held in its adjusted position during the operation of the feeding mechanism. As shown, the gib 21 is provided with a pair of openings 26 adjacent the guiding surface 22. These openings 26 accommodate loosely a pair of fixing screws 27 adapted to be threaded into the feed bar carrier 17 to clamp the gib 21 thereon. In a portion of the gib 21 arranged face-to-face with a lateral extension 25 provided on the feed bar carrier 17 there is formed a third circular opening 30 which receives an eccentric section 35 of a pivotstud 31. The stud 31 is formed with a reduced end portion 32 adapted to be clamped in a feed-advance crank arm 33 extending upwardly from the rock shaft 12, thereby to transmit a horizontal feed movement to the feed bar carrier 17 in the usual manner. Concentric with the reduced end 32 the stud 31 is formed with a body portion 34 journaled in an opening 30 of the feed bar carrier17.

The feed bar 20, which is slidably carried in the slideway 19 of the feed bar carrier 17, is formed with

surfaces

37 and 38 complemental to the slideway guiding

surfaces

18 and 22, respectively, and carries at its upper end a feed dog 39 having the usual serrated feed teeth 40 which are adapted to project through a suitably slotted throat plate 41 secured upon the work arm 10. The lower portion of the feed bar 20 is formed with a yoke 42 having horizontally disposed limbs embracing the upper and lower surfaces of the feed lift eccentric 13.

When it is desired to adjust the slideway 19 of the feed bar carrier 17 to accommodate the feed bar 20 the feed bar is positioned within the slideway 19 and the fixing screws 27 are loosened and the reduced end 32 of the stud 31 is released from its driving connection with the crank arm to permit the stud 31 to be turned. Hence, when the stud is turned the eccentric 35 seated within the opening 3% of the gib 21 is effective to shift, within the limits of eccentricity of the eccentric 35, the guiding surface 22 toward or away from the. opposed integral guiding surface 18 on the feed bar carrier 17. The eccentric 35 is turned until the complemental surfaces of the slideway i9 and the feed bar 20 are in sliding contact along their entire lengths. Thereupon the fixing screws are again tightened to clamp the gib 21 onthe feed carrier bar 17 and the stud 31 fixedly secured to the crank arm 33.

In the operation of the above described feeding mechanism, which operation is more fully described in the hereinbefore identified patent to Dimond, the feed bar carrier 17 is movable in a substantially horizontal path to impart feed advance and return movement and the feed bar 2% is vertically movable while at the same time partakingof the horizontal movement of the feed bar carrier 17. As is readily apparent, the substantially horizontal path of the feed bar carrier 17 is along a slightly arcuate path, due to the rocking movement of the rock shaft 12. Since the feed bar 17 with its lateral extension 25 is locked with respect to the gib 21 by the screws 27 during operation of the machine, the feed bar and gib must turn as a unit on the

portions

34 and 35 of the pivot stud which portions are eccentric one relative to the other. Under some circumstances, therefore, and particularly when the feed bar carrier is at either extremity of the feed advance movement, the pivotal movement of the feed bar carrier 17 together with the gib 21 on the pivotstud 31 will cause a binding. Accordingly, to avoid this binding action the eccentric portion 35 of the stud 31 and the opening 39 in which it is disposed are formed to provide a slight clearance such that when the feed bar carrier 17 arrives at either of the extremities of its horizontal travel it may oscillate slightly about the journal 34 of the stud 31 without binding on the eccentric portion of the stud.

The second embodiment of the invention, shown in Figs. and 6, is similar in general construction to the embodiment shown in Figs. 1-4 inclusive and the same numerals have been used to identify similar parts. The primary difference between this embodiment and the first embodiment is in the means for selectively positioning the feed bar gib on the feed bar carrier such that the adjustment of the feed bar gib on the carrier may be accomplished without regard to possible binding of the feeding mechanism as described above in connection with the first embodiment.

As shown, there is positioned on the right side of the feed bar carrier 17 a gib 43 having an undercut guiding surface 44 opposed to and spaced from the undercut surface 18 to form the slideway 19 which is adapted to receive and guide the feed bar 20 for vertical movement. For the purpose of adjustably securing the gib 43 on the feed bar carrier 17 such that the surface 43 can be set parallel to the surface 18 there is provided a sleeve 45 having a slotted head 46, an intermediate eccentric section 47 seated within an opening 48 provided in the gib 43, and a lower reduced coaxial section 49 which is turnably journaled in an opening 50 formed in the feed bar carrier 17 Coaxially journaled in the bore 51 of the sleeve bushing 45 is a reduced end 52 of a stud 53 of which the enlarged end 54 is adapted to be secured to the crank arm 33 in a manner similar to that of the pivot stud 31 disclosed in the first embodiment.

Hence, when it is desired to adjust the gib guiding surface 44 relatively to the surface 18, it is merely necessary to turn the sleeve bushing 45, whereupon the eccentric section 47 seated in the opening 48 is effective to shift the guiding surface 44 laterally toward or away from the fixed guiding surface 18.

For the purpose of guiding the gib 43 for lateral movement and holding it fixed when the desired adjusted position has been achieved, there is provided a fixing screw 55 which is loosely accommodated within an opening 56 formed in the feed bar gib 43 and is threaded into the 4 feed bar carrier 17. A second fixing screw 57 loosely accommodated within an opening 58 and threaded into the feed bar carrier 57 is located adjacent the sleeve bushing such that a portion of its head 59 overlies a section of the head 46 of the sleeve bushing, whereby when the screw 57 is tightened it is effective to clamp the sleeve bushing 45 on the feed bar gib 43 and prevent turning of the former while simultaneously assisting the screw 55 in holding the gib 43 fixedly positioned on the carrier 17.

The operation of the above described feeding mechaniszn is similar to that described in connection with the first embodiment. However, during the horizonal movement of the carrier 17 imparted thereto by the rock shaft 12 through the crank 33, the feed bar gib 43 including the sleeve bushing clamped thereto and the carrier 18 are free to turn about the reduced end 52 of the connecting stud 53. This relative turning of the gib 43, carrier 1'7 and sleeve bushing 45 about the connecting stud 53 precludes the possibility of binding between the sleeve eccentric portion 47 and the gib 43.

Having thus set forth the nature of the invention, what I claim herein is:

1. In a feeding mechanism for a sewing machine of the type having a rotary actuating shaft journaled in said sewing machine, an eccentric carried by said shaft, a feed bar carrier supported on said shaft for feed advance movement transverse to said actuating shaft, a feed bar embracing said eccentric and slidable on said feed bar carrier in a direction normal to said feed advance. movement of said feed bar carrier, a rock-shaft journaled in said sewing machine, and a crank arm fixedly secured to said rock-shaft and connected to said feed-bar carrier for effecting feed advance movement thereto; the improvement comprising an adjustable slideway having a pair of spaced opposed guiding surfaces provided on said feed bar carrier for maintaining the movement of said feed bar substantially normal to said feed advance movement, said slideway including a gib disposed against said feed bar carrier and having a guiding surface forming one of said slidewa guiding surfaces, and means adjustably mounting said gib on said feed bar carrier including a stud carried by said feed advance crank arm, said feed bar carrier and said gib being formed with overlapping apertures each disposed to accommodate said stud, an eccentric carried on said stud and disposed to engage the aperture in said gib, and means for turning said eccen tric to move said gib toward or away from the other of said guiding surfaces. 7

2. In a feeding mechanism for sewing machines comprising a rotary actuating shaft, an eccentric carried by said shaft, a feed bar carrier supported on said shaft for feed advance movement transverse to said actuating shaft, a feed bar embracing said eccentric and slidable on said feed bar carrier in a direction normal to said feed advance movement of said feed bar carrier, a rock-shaft including a crank arm connected to said feed bar carrier for effecting feed advance movement thereto; the improvement comprising an adjustable slideway having a pair of spaced guiding surfaces provided on said feed bar carrier for maintaining the movement of said feed bar substantially normal to said feed advance movement, said slideway including a gib having a guiding surface forming one of said slideway guiding surfaces, fastening means loosely accommodated by said gib for fixedly securing said gib on said feed bar carrier and a stud connecting said feed bar carrier to said crank arm, said stud having an eccentric portion engageable with said gib adapted adjustably to move said gib toward or away from the other of said guiding surfaces upon turning of said stud.

3. In a feeding mechanism for sewing machines comprising a rotary actuating shaft, an eccentric carried by said shaft, a feed bar carrier supported on said shaft for feed advance movement transverse to said actuating shaft, a feed bar embracing said eccentric and slidable on said feed bar carrier in a direction normal to said feed advance movement of said feed bar carrier, a rock-shaft including a crank arm connected to said feed ba'r carrier for effecting feed advance movement thereto; the improvement comprising an adjustable slideway having a pair of spaced guiding surfaces provided on said feed bar carrier for maintaining the movement of said feed bar substantially normal to said feed advance movement, said slideway including a gib having a guiding surface forming one of said slideway guiding surfaces, fastening means loosely accommodated by said gib for fixedly mounting said gib on said feed bar carrier, and a stud journaled in said feed bar carrier and connected to said crank arm, said stud having an eccentric portion operatively asosciated with said gib whereby upon turning of said stud said gib may be adjustably moved toward and away from the other of said guiding surfaces.

4. In a feeding mechanism for sewing machines comprising a rotary actuating shaft, an eccentric carried by said shaft, a feed bar carrier supported on said shaft for feed advance movement transverse to said actuating shaft, a feed bar embracing said eccentric and slidable on said feed bar carrier in a direction normal to said feed advance movement of said feed bar carrier, a rock-shaft including a crank arm connected to said feed bar carrier for effecting feed advance movement thereto; the improvement comprising an adjustable slideway for maintaining the movement of said feed substantially normal to said feed advance movement, said slideway including a guiding surface along one side of said feed bar carrier and integral therewith, a gib positioned on the other side of said feed bar carrier and having a guiding surface opposed to and spaced from said integral guiding surface, and means mounting said gib on said feed bar carrier including a stud connecting said carrier to said crank of said rockshaft and having an eccentric portion seated within said gib and adapted adjustably to move said gib toward or away from said integral guiding surfaces upon turning of "said stud.

5. In a feeding mechanism for sewing machines comprising a rotary actuating shaft, an eccentric carried by said shaft, a feed bar carrier supported on said shaft for feed advance movement transverse to said actuating shaft, a feed bar embracing said eccentric and slidable on said feed bar carrier in a direction normal to said feed advance movement of said feed bar carrier, a rock-shaft including a crank arm connected to said feed bar carrier for effecting feed advance movement thereto; the improvement comprising an adjustable slideway for main taining the movement of said feed substantially normal to said feed advance movement, said slideway including a guiding surface along one side of said feed bar carrier and integral therewith, a gib positioned on the other side of said feed bar carrier and having a guiding surface opposed to and spaced from said integral guiding surface, and means mounting said gib on said feed bar carrier including a stud connecting said carrier to said crank of said rock-shaft, said stud being journaled in said feed bar carrier and having an eccentric loosely seated within said gib for permitting limited oscillation of said feed bar carrier relatively to said stud and adapted adjustable to move said gib toward or away from said integral guiding surface upon turning of said stud.

6. In a sewing machine having instrumentalities openable upon work fed through the sewing machine, mechanisms for actuating said instrumentalities, at least one of said mechanisms including a first member movable in a single plane, means for moving said first member including a rock arm having a pivotal connection with said first member, a slideway formed on said first member and comprising a fixed slideway surface formed on said first member and an opposed gib adjustably secured to said first member and forming the other slideway surface, means securing said gib in a set adjusted position, and a pivot-pin pivotally connecting said rock arm with said first member and having an eccentric portion formed thereon and embraced by said adjustable gib so that turning of said pivot-pin will effect adjustment of said gib relatively to said fixed slideway surface, and a second member slidable in said slideway.

7. In a sewing machine including a work manipulating instrumentality having a planar compound movement including a substantially linear component and a component normal to said linear component and actuating mechanism for effecting said planar compound movement including a rock member having a crank for imparting said substantially linear movement and means foriimparting a reciprocating movement normal tosaid linear movement; said work manipulating instrumentality com* prising a bar operatively connected to said vertical reciprocating means, a bar carrier having an adjustable slideway receiving said bar, said slideway including a first guiding surface along one side of said bar carrier and a gib positioned on the other side of said bar and having a second guiding surface opposed to and spaced from said first guiding surface, and means mounting said gib on said bar carrier including a stud connecting said bar carrier to said rock member crank and having an eccentric portion seated within said gib adapted adjustable to move said gib toward or away from said first guiding surface to position said second guiding surface parallel with said first guiding surface and thereby to maintain the movement of said bar within said slideway normal to said bar carrier.

8. In a feeding mechanism for sewing machine comprising a rotary actuating shaft, an eccentric carried by said shaft, a feed bar carrier supported on said shaft for feed advance movement transverse to said actuating shaft, a feed bar embracing said eccentric and slidable on said feed bar carrier in a direction normal to said feed advance movement of said feed bar carrier, a rock shaft including a crank arm connected to said feed bar carrier for effecting feed advance movement thereto; the improvement comprising an adjustable slideway having a pair of spaced opposed guiding surfaces provided on said feed bar carrier for maintaining the movement of said feed bar substantially normal to said feed advance movement, said slideway including a gib having a guiding surface forming one of said slideway guiding surfaces, and means adjustably mounting said gib on said feed bar carrier including a stud extending into said gib and connecting said carrier to said crank of said rock shaft, and an eccentric means seated in said gib and arranged about said stud whereby said gib may be adjustably moved toward and away from the other of said guiding surfaces.

9. In a feeding mechanism for sewing machines comprising a rotary actuating shaft, an eccentric carried by said shaft, a feed b-ar carrier supported on said shaft for feed advance movement transverse to said actuating shaft, a feed bar embracing said eccentric and slidable on said feed bar carrier in a direction normal to said feed advance movement of said feed bar carrier, a rock shaft including a crank arm connected to said feed bar carrier for eifecting feed advance movement thereto; the improvement comprising an adjustable slideway having a pair of spaced opposed guiding surfaces provided on said feed bar carrier for maintaining the movement of said feed bar substantially normal to said feed advance movement, said slideway including a gib having a guiding surface forming one of said slideway guiding surfaces, and means adjustably mounting said gib on said .feed bar carrier comprising a sleeve turnably journaled in said feed bar carrier and formed with an eccentric portion seated in said gib and a stud turnably journaled in said sleeve for connecting said feed bar carrier to said crank of said rock shaft.

10. In a feeding mechanism for sewing machine comprising a rotary actuating shaft, an eccentric carried by said shaft, a feed bar carrier supported on said shaft for 7 feed advance movement transverse to said actuating shaft, a feed bar embracing said eccentric and slidable on said feed bar carrier in a direction normal tosaid feed advance movement of said feed bar carrier, a rock shaft including a crank arm connected to said feed bar carrier for effecting feed advance movement thereto; the improvement comprising an adjustable slideWay having a pair of spaced opposed guiding surfaces provided on said feed bar carrier for maintaining the movement of said feed bar substantially normal to said feed advance movement, said slideway including a gib having a guiding surface forming one of said slideway guiding surfaces, and means adjustably mounting said gib on said feed bar carrier comprising a sleeve turnably journaled in References Cited in the file of this patent UNITED STATES PATENTS 604,005 Dimond et a1 May 10, 1898 1,014,022 Parsons Jan. 9, 1912 2,659,330 Knaus Nov. 17, 1953