US3100468A

US3100468A - Blindstitch sewing machine with eccentric mounting for work support

Info

Publication number: US3100468A
Application number: US95441A
Authority: US
Inventors: Brueggenjohann Georgia
Original assignee: Union Special Machine Co
Current assignee: Union Special Machine Co
Priority date: 1961-03-13
Filing date: 1961-03-13
Publication date: 1963-08-13
Anticipated expiration: 1980-08-13
Also published as: GB955199A

Description

Aug. 13, 1963 T. D. TAYLOR 6 BLINDSTITCH SEWING MACHINE WITH ECCENTRIC MOUNTING FOR WORK SUPPORT l0 Sheets-Sheet 1 Filed March 13, 1961 3, 1963 T D TAYLOR 3,100,468

E WITH ECCENTRIC BLINDSTITCH sEw'ING' MACHIN MOUNTING FOR WORK SUPPORT Filed March 13, 1961 10 Sheets-Sheet 2 Aug. 13, 1963 T. D. TAYLOR BLINDSTITCH SEWING MACHINE WITH ECCENTRIC MOUNTING FOR WORK SUPPORT 1O Sheets-Sheet 3 Filed March 13, 1961.

Aug 1963 D TAYLOR 3,100,468

T. BLINDSTITCH SEWING MACHINE WITH ECCENTRIC Filed March 15, 1961 MOUNTING FOR WORK SUPPORT l0 Sheets-Sheet 4 Aug. 13, 1963 T. D. TAYLOR 3,100,468

BLINDSTITCH SEWING MACHINE WITH ECCENTRIC MOUNTING FOR WORK SUPPORT Filed March 15, 1961 10 Sheets-Sheet 5 Aug. 13, 1963 T. D. TAYLOR 3,100,468

BLIND-STITCH SEWING MACHINE WITH ECCENTRIC MOUNTING FOR WORK SUPPORT Filed March 13, 1961 10 Sheets-Sheet 6 I nu Aug. 13, 1963 T. D. TAYLOR 3,100,468 BLINDSTITCH SEWING MACHINE WITH ECCENTRIC MOUNTING FOR WORK SUPPORT Filed March 15, 1961 10 Sheets-Sheet 7 '7 Aug. 13,1963

T. D. TAYLOR 3,100,468 BLINDSTITCH SEWING MACHINE WITH ECCENTRIC MOUNTING FOR WORK SUPPORT Filed March 13, 1961 10 Sheets-Sheet s Aug. 13, 1963 T. D. TAYLOR 3,100,468 BLINDSTITCH SEWING MACHINE WITH ECCENTRIC MOUNTING FOR WORK SUPPORT Filed March 15, 1961 10 Sheets-Sheet 9 Aug. 13., 1963 T. D. TAYLOR 3,100,468 BLINDSTITCH SEWING MACHINE WITH ECCENTRIC MOUNTING FOR WORK SUPPORT Filed March 13, 1961 10 Sheets-Sheet 10 89d say PIC-3.22.

United dtates Patent @fiice 3,100,468 BLINDSTITCH SEWING MACHINE WITH EiCCEN- TRIC MOUNTING FUR WORK SUPPORT Thomas D. Taylor, deceased, late of Hermann, M0., by Georgia Brueggenjohann, executrir, Hermann, Mo., assignor to Union Special Machine Company, Chicago, 111., a corporation of Illinois Filed Mar. 13, 1%1, Ser. No. 95,441 17 Claims. (Cl. 112-173) This invention relates to a blindstitch sewing machine and more particularly to a novel combination of features involved in the pivoted work apron or support, which carries a node former, and mechanism for rocking the work support during the operation of the machine to form a 2 to 1 or skip type stitch or for eliminating such rocking whenever a 1 to 1 or non-skip type stitch is desired. Simple and reliable means, requiring a minimum of effort on the part of the operator, is also provided for rocking the work support in response to the operation of a knee press or the like. This latter means is such as to provide maximum freedom to the operator in the introduction and removal of work and also such as to permit the work support to rock downwardly in the course of operation of the macihne in forming a skip type stitch and in the feeding of extra thicknesses of Work, such as cross seams, through the stitch forming Zone. Coupled with the foregoing, in a unique manner, is a thread nipper mechanism which is normally inactive but is rendered elfective upon lowering of the work support by the knee press member so as to facilitate breaking of the thread over the looper element as a stitched work piece is removed from the machine.

It has been a primary object of the invention to provide an exceptionally compact and sturdy construction for achieving the foregoing purposes, and one which may be very simply and accurately adjusted and is reliable in its operation. A further object has been the production of a machine of the foregoing character which is capable of operation at high speeds.

A feature of the invention is the mounting of the Work apron or support, which is adapted for rocking movements by connections from the main shaft of the sewing machine to produce skip stitches, on pivots adjacent the rear end of the work support. While work aprons or supports have heretofore been mounted on pivots at the rear end of the support, it has been considered necessary, prior to the present invention, to provide forward pivots for work supports which are rocked automatically from the main drive shaft of the machine to produce skip stitches. In accordance with the present invention, the great advantage of rear pivots, in providing substantial clearance between the work support and the fixed presser foot for the insertion and removal of work, has been achieved in a machine having a node former mounted on a shaft carried by the Work support so as to make possible the selective formation of skip stitches by the automatic rocking of the work support or non-skip stitches by eliminating such rocking of the work support. Moreover, the construction provided by the invention is such that the work support is given a compound movement upon the operation of the knee press. It is given a downward and slightly forward movement at its pivotal support, by virtue of an eccentric mounting of the pivot on the frame of the machine, and it is rocked downwardly about its pivot to give the forward end a substantial further downward movement. This greatly increases the space between the entire work support and the presser foot as the knee press is operated. A special toggle linkage is provided adjacent the forward end of the work support to bring about this compound movement, and a spring is provided for restoring the parts quickly and accurately to their normal positions upon release of pressure on the knee press.

Patented Aug. 13, 1963 Another feature of the invention is the provision of a very simple and reliable mechanism, capable of quick adjustment, to predetermine whether the work support will be held stationary during successive cycles of operation of the machine or will be rocked during certain cycles to provide a skip stitch. This mechanism involves an eccentric control disk arranged to be driven at a half or a third or similar fraction of the angular speed of the main drive shaft. Adjacent this control disk is another disk mounted to turn about the same shaft which carries the control disk and provided with a concentric peripheral surface of a radius equal to the major radial distance of the periphery of the control disk. This second mentioned disk has a depression in its periphery which may be shifted into and out of a position to cooperate with a roller which ext-ends across at least a partof the periphery of both disks. By simply shifting a lever or the like,rto predetermine the location of the depression of the concentric disk, the machine may be set to produce either skip stitches or non-skip stitches. The roller mentioned is connected with a rock member which is in turn connected with the toggle linkage discussed above to bring about a slight rocking movement of the work support during predetermined cycles of the machine when a skip stitch has been selected. Readily adjustable means is also provided for shifting the pivotal axis of the rock member to accurately adjust the depth of penetration of the needle of the machine into the node of the work being stitched. By depth of penetration is meant the distance below the top of a node formed in the work that the needle passes through such node.

A'further special feature of the invention is the provision of a simple connection from the shaft about which the work support is rocked to bring about automatic operation of the thread nipper mechanism 'mentioned, whenever the work support is moved downwardly by the knee press for insertion or removal of work.

Still another feature of the invention is the provision of simple, effective and reliable mechanism for constantly swinging the node former through the same arcuate path, regardless of whether the machine is set for the production of skip stitches or non-skip stitches. The determination of the type of stitching to be produced, skip or non-skip, is left entirely to the rocking or non-rocking of the work support in the course of operation of the machine.

A still further feature of the invention is the provision of a toggle mechanism for retaining the work support in a desired position. This toggle mechanism is such that the work support may be easily and reliably shifted to accommodate different thicknesses of work, to produce skip stitches, and to lower the work support for the insertion and removal of work, but is quickly restored by spring means to its normal position after downward movement for any of the purposes specified.

An additional feature of the invention has been to provide a quickly and readily adjustable means for predetermining the normal position of the work support and the particular are through which the work support is rocked in the course of forming skip stitches. This feature is closely related to the proper positioning of the node or ridge former in the production of skip and non kip stitches. r

Other objects, features and advantages of the invention will appear from the following detailed description of an illustrative embodiment of the same which will now be given in conjunction with the accompanying drawings, in which:

FIG. 1 is a view, partly in planand partly in horizontal section, of a sewing machine embodying the invention, the work support or apron being omitted;

FIG. 2 is a plan view of a portion of the sewing machine showing the work support and adjacent portions of the frame structure;

FIG. 3 is a vertical sectional view through the machine taken along the line 33 of FIG. 1;

FIG. 4 is a front elevational view of a part carried by the work support, with a portion of the forwardly extending arm of the main frame shown in section; 7

' chine taken along the line 7-7 of FIG. 1;

FIG. 8 is a vertical sectional view of certain parts taken along the line 8-8 of FIG.

FIG. 9 is a perspective view of an element shown in FIG. .8;

FIG. 10 is aventical sectional view through a portion of the machine taken along the line 10-10 of FIG. 1;

FIG. 11 is a ventical sectional view taken transversely through the work supportand the adjacent portion of the frame of the machine along the line 11-11 of FIG. 1;

FIG. 12 is a detail view of certain partsshown in FIG. 11;

FIG. 13 is a bottom view of the right hand portion of the frame of the machine shown in FIG. 1;

'FIG. 14 is a ventical sectional view taken along the line 14.14 of FIG. 1 and shows a nipper mechanism embodied in the machine;

- FIG. 15 is a perspective view of a bracket member shown in FIG. 14;

FIG. 16 is a perspective view of a pivoted member carried by the bracket shown in FIG. 15;

.FIG. 17 is a bottom plan view of a plate member provided at the top of the frame;

FIG. 18 is a perspective view showing a portion of a Lewis 150 type machine. This is adapted to form a single thread blindstitch, but it should be understood that the present invention could be applied to a machine adapted to produce a two thread blindstitch, of either the chainstitch or lcckstitch types.

The mechanism for operating the stitch forming devices, including acurved needle and a recipnocatory and oscillatory loo-per, and also for operating a top feed dog, will now' be briefly described. 'Adjacent the left'end of the main shaft 15 of the machine there is secured thereto a spherical eccentric 17 (FIG. 1) at the rear end offthe arm 12. This eccentric cooperates with a strap 18 connected with a pi-tman whose opposite end is pivotaily connected with an arm (not shown) secured to a shaft 1 9 suitably journaled in the frame arm 12 (FIG. 3). At the forward end of shaft 19 there is secured an arm 20 which carries a curved needle 21. It will be understood that through the connections described the needle will be reciprooated along an arcuate path tion27 of a crank 28 secured to the shaft 15. Intermedithe work support and certain mechanism connected therei with for positioning and controlling the movement of shown in FIG. 2.2,taken along the line 23-23- of the latter. i

Referring now to the drawings, the illustrative machine comprises a main frame having a base portion 10 (FIGS. 1, 2, 3 and 7) having, at its rear part, an upstanding portion 11 which carries, at its upper end, an arm 11a that projects toward the left (FIG. 1) and has secured thereto, at its left end, a forwardly extending arm 12. Mounted [for rocking movement upon the portic-n1 10 of the frame is a work support or apron 13 (FIG. 2) having anextension 14 to which is secured a frame member 14a positioned beneath the forward end of the arm 12. A main'rotary drive shaft 15 is suitably journaled in the portion 11 and arm 11a of the frame, this shaft extending outwardly of the frame at its right end (FIG. 1) and having secured thereto a combined handwheel and prulley 16 through which the machine may be operated. .It will beunderstood that the pulley may suitably be connected by a belt to an appropriate power sounce such as an electric motor and clutch unit of conventional construction.

The blindstitch sewing machine to which the present invention may be appied may be of any suitable type, but the invention has been illustrated in connection with ate its length, the rod 23 is supported for turning and swinging movements in the manner disclosed in the patent to Mueller, No. 2,5 88,274, gnanted March 4, 1952. As will be .clear from that patent, the arrangement is such that the looper 22 is given \a compound movement swinging movements from one side to the other of the node former, to be described. In the course of such oscillatory or swinging movement of fingers of the looper are turned through an angle of about 90".

For advancing the work in the course of stitch formation a top feed dog 29 (FIG. 1) is provided. This feed dog is secured to a feed bar 30 extending longitudinally of the arm12 and having a strap 31 surrounding an eccentric 32 secured to the main drive shaft 15. Eccentric 32 may be of the adjustable type to enable variation in the extent of the feed stroke imparted to the feed dog during each cycle of the machine. Intermediate its ends the feed bar 30 is supported for rocking and longitudinal movement by a member 30a. The arrangement for this purpose may. be of the character disclosed in the patent to Mueller, No. 2,109,014, granted February 22, 1938. As will be understood, the feed dog 29' is moved through an elliptical path by the operation of the eccentric 32.

.It is thus lowered into engagement with the work, then is urged upwardly against the underside of a fixed presser foot 33 which has an opening therethrough for the passage of the feed dog 29.

As best shown in FIGS. 4, 5 and 6, the means for urging the work upwardly against the undersurface of the presser foot 33 and against the feed dog, when the latter is imparting its feed movement to the work, comprises a pair of

platens

34 and 35 which are disposed at opposite sides of the node former to be described. The two platens are mounted in a similar way, the mounting of. the platen 34 being most clearly shown in FIGS. 5 and 6.. It is rockably mounted at the upper end of an arm '36 pivotally connected by a screw stud 37 to the member 14a of the frame. A spring 38, connected at one end with a screw member carried by the frame member 1411 and at its other end with a downwardly extending projection from the arm 36 serves to urge the latter in a clockwise direction and to thus urge the platen 34 against the presser foot 33. The two platens are forced downwardly against the action of the springs as the work is advanced along the undersur-face of the presser foot 33. When the work support 14 and its extension 14a are rocked downwardly upon the operation of a knee press, in the manner to be explained, a projection 39 of the arm 36 is urged by the spring 38 into engagement with the upper edge of a plate 40 secured to the frame member 14a. This prevents undue rocking 0f the arm 36 which carries the platen 34. As stated, the same arrangement is provided for the platen 35. p 1

Turning now to the mounting of the work support on the frame of the machine, the portion 13 of the work support is provided with rearwardly extending bearing

portions

41, 42 and 43 (FIG. 2) which cooperate with a shaft 44 to permit rocking movement of the work support about the axis of that shaft. Shaft 44 is supported at its two ends eccentrically of the axis of the shaft. Thus, at the left end a pointed pivot screw 45, having threaded engagement with a lug 46 of the frame member 18, cooperates with a conical recess 45a in the left end of shaft 44 (FIGS. 1, 2. and 7) which is disposed eccentrically to the axis of the shaft. When properly adjusted the screw 45 is retained in set position by a set screw 47. Similarly, the right end of the shaft 44 is supported by the pointed end of a screw 48 having threaded engagement with a lug 49 of the frame It}. The pointed end of this screw cooperates with a conical recess 48a in the right end of the shaft 44 which is axially alined with the recess 45a in which the pointed end of screw 45 is inserted. Screw 48 is retained in adjusted position by a set screw 58 (FIG. 2). The shaft 44 is caused to turn through a suitable angle under certain conditions about the eccentrically disposed pivot screws 45 and 48. When it is so turned it tends to bring about slight lifting and lowering movements of the pivoted portion of the work support. As will be explained, it is turned in a direction to cause lowering of the pivoted portion of the work support in response to operation of a knee press and it is turned in the opposite direction by a spring.

Forwardly of the shaft 44 the work support 13 is held in its normal position, shown in FIG. 7, by a toggle linkage. This includes a member 51, shown in detail in FIG. 21, which is pivotally mounted on a rod or pin 52. It also includes a member 53, shown in detail in FIG. 20, which is pivotally mounted upon a pin or screw stud 54 carried by a downwardly extending lug 13a of the work support 13. Member 51 has an outwardly extending bearing element 55 adapted to fit between bearing lugs 53a on the member 53. A pin 56 which is passed through the bearing lugs 55 and 53a serves to pivotally interconnect the two

members

51 and 53. Also pivotally mounted on the pin 56 is the end of a bar 57 having a forked portion 57a which straddles the lugs 53a and has an opening in each arm of the fork surrounding the pin 56. At its opposite end the bar 57 is pivotally connected by a pin 58 with a portion of a projection 59 which extends downwardly at an angle from a collar 60 secured to the shaft 44 (FIGS. 2, 7). As indicated in FIG. 1, the collar 68 is provided with a groove extending around a portion of its circumference to accommodate the bar 57. The collar is secured to the shaft 44 by a set screw 68:: (FIG. 2).

Also secured to the shaft 44 at some distance from the collar 69 is another collar 61 having a set screw 61a to lock it to the shaft (FIGS. 1, 2 and 14). Connected with the collar 61, at a point below and at one side of the axis of the shaft 44, by means of a screw 62 is a link 62a to the outer end of which is connected a spring 63 The opposite end of the latter is connected with a screw stud 64 carried by the main frame of the machine and linkage is limited by the engagement of a shoulder 65 on member 53 with a shoulder 65a on member 51.

Toggle member 51 is pivotally connected by the pin 52 with an arm 66 of a rock member which is shown in detail in FIG. 19. Its general relation to other parts is shownin FIG. 7. A long cylindrical hub portion 66a of the rock member is secured by set screws 66b to a shaft 67 rockably mounted in the frame of the machine. In the plane of the arm 66, but at the opposite side of the axis of the shaft 67, is a downwardly extending arm 68. This carries a screw member 69 to which is attached one end of a spring 70, the opposite end of which is connected to a screw stud 71 adjustably carried by the frame of the machine. An arm 72 extending downwardly from the opposite end of the sleeve 66a has pivotally connected therewith a link 73, this being connected to arm 72 by means of a pivot pin 72a. Link 73 is connected with a block 75 by a screw member 74 provided with nuts for varying the position of the block 75 in relation to link 73 and thus varying the effective length of the .link. Block 75 has trunnions 76 extending outwardly from its opposite sides and providing bearing means for the forked lower end of an L-shaped lever 77. The latter is connected by a pivot pin 78 with a flattened portion of a cylinder 79 adjustably mounted in an opening in the main frame of the machine. Adjacent the right end of the lever 77 (FIG. 7) there is rotatably mounted thereon a roller 80, the latter being journaled upon a screw threaded pivot pin 80a. Roller 80 is adapted to cooperate with the periphery of two disk-

like members

81 and 82 which are mounted in side by side relation upon a shaft 83 (FIGS. 7-10, inclusive). Member 81 has a major portion of its periphery of cylindrical form, concentric with the axis of the shaft 83, but it is provided with a depression or indentartion 81a in one region of its periphery. A sector-like recess 81b is provided in the periphery of disk 81 at the opposite side of the shaft 83 and a pin 84 extends across this recess. This pin cooperates wtih a notch in the lower end of a lever 85 which is rockably mounted on the main drive shaft 15 of the machine. Lever 85 extends upwardly through an opening 85a in a closure plate 85b secured to the top of portion 11 of the frame (FIGS. 10 and 17). A member 85c secured to the underside of the plate 85b serves to retain the lever 85 in either of the two positions into which it may be shifted. A spring 85d serves to urge the lever 85 toward the right (FIG. 10) at one side or the other of the member 850 to retain the lever in its set position. An opening 85a in the plate 85b permits the introduction of lubricant to certain parts of the mechanism.

A gear 86 secured to the shaft 15 meshes with a larger gear 87 rotatable on the shaft 83. If the machine is intended to provide a two to one type of skip stitch when desired, the gear 87 will be given one revolution for each two revolutions of the gear 86. Should a three to one type of skip stitch be desired, the

gears

86 and 87 should be such as to bring about one revolution of the latter for three revolutions of the gear 86. Disk member 82 is secured to the gear 87 and therefore rotates with the latter. The disk 82 is mounted on gear 87 slightly eccentrically in relation to the axis of the latter and of the shaft 83, so that in the course of its rotation it tends to force the roller 80 downwardly once upon each two revolutions of the main shaft. However, this is done only when the depression 81a of disk 81 is positioned directly over the roller 80. Disk 81 may be brought into such a position by moving the lever arm 85 (FIG. 8) toward the left so as to cause a limited clockwise rotation of the disk 81. When the latter is in the position shown in FIG. 8 its cylindrical surface will retain the disk 80 in a fixed vertical position and will not permit the latter to rise as the portion :of the periphery of disk 82 which is of less distance from the axis of the shaft 83 is positioned over the disk 80. Thus, by a simple turning of the member 81 the machine may be set for either a 1 to l, non-skip stitch, 'or a skip type stitch. In this connection it should be noted that upwardmovement of the roller 80 (FIG. 7) serves to rock the arm 72, shaft 67 and arm 66 in a counterclockwise direction. Such rocking movement, it will be understood, is brought about by the spring 70 when the machine is adjusted for a skip type stitch and the low portion of the eccentric disk 82 is brought into engagement with the roller 80. The resulting downward rocking of the arm 66 will carry the toggle link 51 slightly downwardly and this in turn will draw the toggle link 53,.and hence the work support 13;, slightly downwardly. The extent of such downward movement of the work support is just suflicient to permit-a skip stitch to be formed.

Shoulders

65 and 65a on the toggle links will be separated slightly at this time.

Very simple means is provided for varying the depth of penetration of the curved needle through a node formed in the work. For this purpose the member 79 may be adjusted axially to a limited extent by means of a screw thneaded member 88 (FIG. 7) cooperating with internal.

threads in an opening within the cylindrical portion of member 79. Member 88 carries at'its upper end a knob 89 (see also FIGS. 22 and 23) which is secured to the shank of'member 83 by a set screw 99. The knob 89 is provided with a conical skirt portion 89a carrying suitable indicia to show its setting. Skirt 8% is arranged to turn within a recess provided in the top of a plate 91 secured in any suitable way to the main frame of the machine. Member 88 has a collar 88!; above the screw threaded portion of the member and has a. cylindrical stem 88a above the collar. On this stem there are mounted two

washers

88c and 88d between which is positioned a ball bearing assembly 88a. As best shown in FIG. 7, the washer 88c rests upon the collar 88b while the washer 38d engages the undersurface of the member 91. The latter is provided with a notch 91a adapted to cooperate with the indicia on the shoulder 89a to show the particular setting of the parts; Screws 911!) may be employed for securing the plate 91 to the frame of the machine. Washers 89b and 890, (FIGS. 22 and 23) retaining between them another ball bearing unit, are mounted on the stem 88a above the upper surface of member. 91. A spring urged ball 89d carried by the knob 89 cooperates with spaced depressions 910 in the upper surface of member 91 to retain the knob and the screw member 88 inwhatever position they may be set. Preferably the knob 89 is limited to one. revolution in relation to the member 91 and this is brought about by 'a-downwardly extending stem of a screw 89s carried by the knob arranged to cooperate with an upwardly extending screw jhld (FIG. 7)

, which is in the path of movement of screw 896.

It will be appreciated that when the knob 89 is turned in a direction to shift the member 79 downwardly, the pivot 73 for the lever 77 will be moved downwardly about the axis of the roller 89. This causes a slight movement of the trunnions 76 toward the right (PEG. 7) and hence a. slight counterclockwise movement of the shaft 67 with the result that the work support 13 is lowered slightly. This will correspondingly reduce the depth below the'top of the node of the work at which the curved needle passes through such node. Turning of the knob 89 in the opposite direction will bring about the opposite result.

Means are provided for enabling the operator to bring about down-ward movement of the Work support at will, with a minimum of etfort. For this purpose there is shown a knee press member (FIG. 1) connected with a bent rod 93'h aving an upwardly, then forwardly, the-n upwardly, then laterally and then rearwardly extending portions. The rearwardly extending portion of the rod is connected by a coupling member 94 with a shaft 95 journaled in the base portion of the frame of the machine. A collar 96 secured to shaft 95 retain-s it against outwardmovement while the coupling 94 retains it against inward movement. Atthe inner end of the shaft there is a screw stud 102; The roller 101 is normally spaced a slightdistance below an arm 1%3 integual'wi-th the toggle member 51. it will turn the shaft -99 through a suitable angle and will cause the arm 10b to rock in a clockwise direction (FIG. 18). At this time the roller 101 will engage the arm 103 and will cause the toggle member 51 to rock counterclockwise about the pivot 5-2. It will be understood that this will also cause the toggle member 53 to swing outwardly, or clockwise, and by virtue of the link 57 connected with collar 60 it will cause rocking of the shaft 44 in a clockwise direction. Such rocking of the shaft 44 will be resisted by the spring 63 which will serve to restore the parts to their normal position when the force is removed from the knee press. To limit the extent of rocking of the

shafts

99 and 44,through the operation of the knee press, an adjustable screw 1% is mounted in the arm 199 and is adapted to engage the surface of the hub portion 664; of the rock member 66 etc. shown in FIG. 19, which at this time will be in a predetermined position.

To insure having the roller 161 norm-ally located a slight distance below the arm 193, so that the latter will not engage the roller due to slight lowering of the work 7 has one end connected with the pin 99a andits other end with a pin 99c extending inwardly from the trame of the machine. Adjacent the opposite end of the shaft 99 there is secured a collar 99:! carrying a screw element 3% which cooperates with a pin 99 carried by the frame to limit the extent of rocking of the shaft by the spring 995.

As has been stated, a node former is mounted for rocking or oscillatory movement in the work support. This is best shown in FIGS. 36, inclusive. It comprises a segment 105, preferably having its upper, circumferential edge beveled to facilitate its creation of a fold or node in the work at the time the needle is being passed through the latter. The node former #195 is secured to a shaft 196 journaled in suitable bearing sleeves 1&7 and 198 carried by the work support (13, 14, 14a). A collar 1tl9 secured to the shaft 106 is arranged to cooperate with the left end of the bearing sleeve 108 to prevent movement of the shaft toward the right (FIG. 3). An arm .1163 is clamped to the shaft ltldadjacent the opposite end of bearing sleeve to? and serves to prevent shifting of the shaft 166 toward the left. Arm 110 (FIG. 7) has pivotally connected therewith, by means of a screw stud 1-11, a pitman 1-12. of substantially L-shaped configuration, the .upper end of this pitman having a strap 113 which cooperates with an eccentric 114 secured to the shaft 15. it will be apparent that upon each revolution of the shaft 15 the p-itman 112. will impart a rocking movement to the arm i110 and hence to theshaft 106, and therefore also to the node former 105. In accordance with the invent on the node former is given the same extent and path of movement upon each revolution of the shaft 15 regardless of whether the machine is set for the production of skip stitches or non-skip stitches.

For controlling the tension on the needle thread at various times during the operation of the machine, there is provided a thread tensioning device 115, with provisions for automatic release of tens-ion during certain portions of a cycle of the machine, and a thread nipper 116 which becomes effective only when the work support is lowered by the knee press to introduce or remove work. It will be understoodthat the thread from a cone, or other suitwhich meshes with a bevel When the knee press member is actuatedi9 able source of supply, .is passed between the tension applying disks of the unit 116 and then of the unit 115 (FIGS. 3 and 10) from which the thread is delivered through suitable guides to. the needle. The thread tensioning device 115 is controlled by a pin 117 whose normal position may be adjusted by changing the height of the sleeve through which it extends so that the posit-ion of the lower end of the pin, in its lowermost position, may

be varied slightly and thus alter the duration of the portion of a cycle of the machine during which the tension applied to the thread by this device is released. The lower end of the pin 117 cooperates with an eccentric 118 carried by a sleeve 119 secured to the shaft 15. The

eu'xgmlsr position of the sleeve .119 in relation to the shaft may be varied by loosening a set screw 11%, then turning these parts in relation to each other, and then retightening the screw. This will determine the portion of a cycle of operation of a machine during which the tension is applied to the thread and during which it is released from the thread. It will be understood that the arrangement is such that the upper end of pin r117 engages the bottom of a member which is normally urged downwardly by a spring 120 into enga ement with the uppermost of the two tension applying disks 121. The eccentric 1131s such that during a certain portion of a cycle of the machine the pin 117 will be lifted to offset the force of the spring 120 but at other portions of a cycle the pin will be lowered so that the spring 12% is effective to apply its tensioning force to the thread.

The thread nipper mechanism 116 has a spring 122 whose force may be varied by adjustment of a nut 122.1 to apply a nipper force to the thread. The lower end of spring 122 cooperates with a cuplike member 123 which is urged by the spring against the uppermost of a pair of thread tension applying disks 124. During the normal operation of the machine the member 1'23 is held in a slightly elevated position by the upper end of a pin 125 so that no tension will be applied to the thread in its passage between the disks 124. Pin 125 has a threaded lower portion 125a (FIG. 14) which permits adjustment of the height of the pin in relation to a vertically extending rod 126 to which the pin is attached. At its lower end the rod 126 is pivotally connected with an arm 127 of a member shown in detail in FIG. 16. Member 127 is rockably mounted on a bracket 128 (FIG. which is secured to an inclined surface provided on the frame of the machine. A downwardly extending arm 127a of the member 127 has an opening surrounding a rod 129 which carries a collar 130 that is normally urged in the manner to be explained, against the left face of the arm 1270. The upper left end of the rod 129 cooprates with a downwardly extending arm 131 of the member 61 secured to shaft 44. It will be recalled that the member 61 is normally urged in a counterclockwise direction (FIG. 14) by the spring 63. As so urged the arm 131 forces the rod 129 toward the right and by virtue of the collar 130 serves to rock the member 127 in a counterclockwise direction. Tnis causes lifting of the rod 126 and pin 125 to raise the element 123 sufiiciently to overcome any force 'of the spring 122 tending to urge the disks 124 into tension applying relation to the thread. However, when the shaft 44 is rocked in a clockwise direction by the action of the knee press, in the manner described, the arm 131 will be drawn away from the end of the pin 129'so that the rod 126 will be permitted to drop by gravity, and initially under the force of the spring 122. Movement of the rod 129 toward the left is limited by a collar 132 secured thereto which cooperates with an arm of the bracket 128.

It should be understood that the knee press is normally operated to bring about the results above described when the needle is retracted from the node of Work and is in substantially its leftmost position. At this time the thread tensioning device 115 will be inactive by virtue of the lifting of pin 117 by eccentric 118. The application 10 of the relatively strong tension to the thread by the nipper mechanism 116 at this time enables the operator to break the thread over the edge of the looper by simply removing the work from the machine by a snapping movement of the hand.

It is believed that the mode of operation of the machine of the various mechanisms embodied in the improved machine, and their cooperative relationship, will be understood from the foregoing detailed description of an illustrative embodiment of the invention. A compact arrangement of the various devices has been provided in a manner to insure reliable operation thereof, with a minimum of effort being required on the part of the operator to lower the work support into a position to facilitate the introduction and removal of work. Simple and reliable devices are provided for predetermining whether the machine is to produce a non-skip stitch or a skip type stitch and also to regulate the depth below the top of the node former at which the curved needle passes through the node of work. A highly desirable control over the tension on the needle thread is provided in a very simple and effective manner. This is such that during the normal operation of the machine, tension will be applied to the needle thread during a certain portion of a cycle and will be released during another portion of the cycle, such release taking place during the time that the needle is retnacted from the work and is near its extreme leftmost position, thus avoiding danger of breakage of the thread as the looper carries a seized loop of the thread from the right side over to the left side of the node former. To facilitate severing of the thread after completion of the desired seam, the lowering of the work support by the operation af a knee press, or the like, serves to apply a nipping action to the needle thread so that it may be readily snapped over the looper as the work is removed from the machine. 1

While a preferred embodiment of the invention has been described in considerable detail, it will be understood that various modifications may be made in certain portions of the mechanism within the scope of the appended claims.

What is claimed is:

1. In a blindstitch sewing machinehaving a frame, a rotary drive shaft journa-led in said frame, and means for advancing work from the front toward the rear of said frame, the combination which comprises a work supporting member along which the work to be stitched is advanced, said work support being pivotally connected with said frame for rocking movements about an axis extending transversely of the direction of feed of the work, said axis being disposed adjacent the rearward end of said work support as viewed in the direction of feed of the work, cylindrical means cooperating with said work support to provide said axis, pivot means on said frame of the machine cooperating with said cylindrical means eccentrically of said axis, a node former rockably mounted on an axis which is in fixed relation to said work support and positioned forwardly of the axis about which said work support is rocked, connections from said drive shaft to said work support for rocking the latter about said first-mentioned axis to produce skip stitches and a single means operable at will for turning said cylindrical means about said pivot means to cause lowering of said first mentioned axis and for rocking said work support about said first mentioned axis to thereby facilitate the introduction and removal of work.

2. In a blindstitch sewing machine of the character set forth in claim 1, a movable member carried by said frame, said connections from the drive shaft to said work support including a toggle mechanism connecting the forward portion of said work support with said movable membercarried by said frame, and connections from said movable member carried by said frame to said drive shaft for enabling the latter to operate said toggle mechanism to rock said work support about its axis.

operable at will being adapted to turn said eccentrically mounted shaft-t vary the location of theaxis thereof.

4. In a blindstitch sewing machine of the character set forth in claim 2, adjustable means in said connections from said movable member carried by said frame to said drive shaft for varying'the normal position of 7 said work support.

In, a blindstitch sewing machine of the character set forth in claim 2, connections from said means operable at will to said toggle mechanism for rocking said work support downwardly about its axis.

6. In a blindstitch sewing machine having a frame, a rotary drive shaft journaled in said frame, and means for advancing work from the front toward the rear of the frame, the combination which comprises a Work supporting member along which the work to be stitched is advanced, said work supporting member being pivotally connected with said frame for rocking movements about an axis extending transversely of the direction of feed of the work, said axis being disposed adjacent the rearward end of said work support as viewed in the direction of feed of the work, a node former rockably mounted on an axis which is in fixed relation to said work support and positioned forwardly of the axis about whichsaid work support is rocked, connections from said drive shaft to said work support for rocking the latter about said first mentioned axis to provide skip stitches, means operable at will for rocking said work support about said first mentioned axis to facilitate the introduction and removal of work, said connections from said drive shaft to said Work support comprising a rock member and a toggle mechanism connecting said rock member with said work support, and means operated by said means operable at will for operating said toggle mechanism to cause downward movement of said work support.

7. In a blindstitch sewing machine of the character set forth in claim 6, said connections from said drive shaft to said work support comprising a second rock memberand a link connecting the latter with said firstmentioned rock member, and readily adjustable means for shifting the axis about which said second rock member is rocked to thereby determine the normal position of said work support.

. 8. In a blindstitch sewing machine of the character set forth in claim 7, said connections from said drive shaft to said work support including an eccentrically mounted disc and connections from the drive shaft for v rotating said disc, means carried by said second rock member in spaced relation to the axis about which said member rocks, said last mentioned means cooperating.

with said eocentrical ly mounted disk for rocking of said second rock member, a detaining member adjacent said disk adapted to cooperate with said last recited means to holdthe same out of engagement with said disk to thereby retain said second rock member against rocking movements, and readily adjustable means for shifting said detaining member into and out of its operative position.

9. In a blindstitch sewing machine of the character set forth in claim 8,.said detaining member being a substantially cylindrical element mounted for turning movement about the axis around which said disk is rotated, said element having a depression in its peripheral surface adapted to be positioned directly opposite said means carried by said second rock member when said element is turned into one position by said last recited readily adjustable means, to thereby enable said disk to rock said second rock member. I

10. In a blindstitch sewing machine of the character setforth in claim 9, said last recited adjustable means comprising a lever pivotally mounted on said frame and frame, and means connecting the opposite end of said lever with said element for turning the latter.

1 1. In a blindstitch sewing machine of the character set forth in claim 8, spring means for urging said second rock member in a direction to hold said means carried thereby against a selected one of said disk and said detainer member.

12. In a blindstitch sewing machine of the character set forth in claim 2, said axis about which said work support is adapted to rock being provided by an eccentrically mounted shaft, a collar secured to said last mentioned shaft, said toggle mechanism comprising a pair of pivotally connected members one of which has its free end connected with the work support and the other of which has its free end connected with said movable member carried by said frame, a link connecting the pivot of said toggle mechanism with a portion of said collar spaced from the axis of said last recited shaft, spring means connected with said last recited shaft urging the latter to turn in a direction which will cause said link to urge said toggle mechanism toward a straightened position, and means for limiting the extent to which said toggle mechanism may be straightened.

13. In a blindstitch sewing machine of the character set forth in claim 6, spring means for urging said means operable at will into an inactive position in which said means operated thereby is moved into a position spaced from said toggle mechanism.

14. In a blindstitch sewing machine of the character set forth in claim 3, spring means connected with said eccentrical ly mounted shaft for turning the same in a direction opposite to that in which it is turned by said means operable at will andfor normally retaining this shaft in a predetermined angular position, a thread nipper mechanism carried by the frame of the machine, means secured to said eccentrically mounted shaft for rendering said nipper mechanism ineffective when said eccentric-ally mounted shaft is in its normal'position, and means for rendering said nipper mechanism effective when said eccentrically mounted shaft is turned by said means operable at will.

l5.'In a blindstitch sewing machine of the character set fonth in claim 1-, a rock shaft upon which said work support is mounted for said rocking movements, spring means for turning said rock shaft and for rocking said work support in a direction opposite to that in which said work support is rocked by said means operable at will and for normally retaining the rock shaft in a predetermined angular position, a thread nipper mecharism carried by the frame of the machine, means secured to said rock shaft for rendering said nipper mechanism ineffective when said rock shaft is in its normal position, and means for rendering said nipper mechanism effective when said rock shaft is turned by said means operable at will. 16. In a blindstitch sewing machine having a frame, a rotary drive shaft journaled in said frame, and means for advancing work from the front toward the rear of said frame, the combination which comprises a work supporting member along which the work to be stitched is advanced, said work supporting member being pivotally connected with said frame for rocking movements about an axis extending transversely of the direction of feed of the work, cylindrical means cooperating with said work support to provide said axis, pivot means on said frame of the machine cooperating with said cylindrical means eccentrically of said axis, a node former rock-ably mounted on an axis which is in fixed relation to said work support and parallel with and spaced horizontally from the axis about which said work support is rocked, connections from said drive shaft to said work support for rocking thelatter about said first-mentioned axis to produce skip stitches, means operable at will for rocking said work support about said axis to facilitate the introduction a rotary drive shaft journaled in said frame, and meansfor advancing work from the front toward the rear of said frame, the combination which comprises a work supporting member along which the work to be stitched is advanced, saidwork supporting member being pivotally connected with said frame for rocking movements about an axis extending transversely of the direction of feed of the work, cylindrical means cooperating with said work support to provide said axis, pivot means on said fname of the machine cooperating with said cylindrical means eccentrically of said axis, a node former rockably mounted on an axis which is in fixed relation to said work support and parallel with and spaced horizontally from the axis about which said work support is rocked, connections from said drive shafit to said work support for rocking the latter about said first-mentioned axis to produce skip stitches, and a single means operable at will for turning said cylindrical means about said pivot means to cause the lowering of said first mentioned axis and for 14 rocking said work support about said first mentioned axis to thereby facilitate the introduction and removal of work, said connections from said drive shaft to said work support for rocking the latter comprising a rock member arranged to be rocked about a predetermined axis, means carried by said rock member in spaced relation to the axis about which it rocks, an :eccentrically mounted disk adapted to be rotated, connections from said drive shaft to said disk for rotating the latter, said disk cooperating with said last-recited means to cause rocking of said rock member, a detaining member adjacent said disk adapted to cooperate with said last-recited means to hold the same out of engagement with said disk and thereby retain said rock member against rocking movements, and readily adjustable means for shifting said detaining means into and out of its operative position.

References Cited in the file of this patent UNITED STATES PATENTS 1,369,773 Bertrand Mar. 1, 1921 2,000,929 Dearborn May 14, 1935 2,129,402 Bowman Sept. 6, 1938 2,250,745 Buono July 29, 1941 2,280,468 Bowman Apr. 21, 1942 2,678,619 Panry May 18, 1954

Claims

1. IN A BLINDSTITCH SEWING MACHINE HAVING A FRAME, A ROTARY DRIVE SHAFT JOURNALED IN SAID FRAME, AND MEANS FOR ADVANCING WORK FROM THE FRONT TOWARD THE REAR OF SAID FRAME, THE COMBINATION WHICH COMPRISES A WORK SUPPORTING MEMBER ALONG WHICH THE WORK TO BE STITCHED IS ADVANCED, SAID WORK SUPPORT BEING PIVOTALLY CONNECTED WITH SAID FRAME FOR ROCKING MOVEMENTS ABOUT AN AXIS EXTENDING TRANSVERSELY OF THE DIRECTION OF FEED OF THE WORK, SAID AXIS BEING DISPOSED ADJACENT THE REARWARD END OF SAID WORK SUPPORT AS VIEWED IN THE DIRECTION OF FEED OF THE WORK, CYLINDRICAL MEANS COOPERATING WITH SAID WORK SUPPORT TO PROVIDE SAID AXIS, PIVOT MEANS ON SAID FRAME OF THE MACHINE COOPERATING WITH SAID CYLINDRICAL MEANS ECCENTRICALLY OF SAID AXIS, A NODE FORMER ROCKABLY MOUNTED ON AN AXIS WHICH IS FIXED RELATION TO SAID WORK SUPPORT AND POSITIONED FORWARDLY OF THE AXIS ABOUT WHICH SAID WORK SUPPORT IS ROCKED, CONNECTIONS FROM SAID DRIVE SHAFT TO SAID WORK SUPPORT FOR ROCKING THE LATTER ABOUT SAID FIRST-MENTIONED AXIS TO PRODUCE SKIP STITCHES AND A SINGLE MEANS OPERABLE AT WILL FOR TURNING SAID CYLINDRICAL MEANS ABOUT SAID PIVOT MEANS TO CAUSE LOWERING OF SAID FIRST MENTIONED AXIS AND FOR ROCKING SAID WORK SUPPORT ABOUT SAID FIRST MENTIONED AXIS TO THEREBY FACILITATE THE INTRODUCTION AND REMOVAL OF WORK.