US2949084A

US2949084A - Sewing machine looper mechanism

Info

Publication number: US2949084A
Application number: US710096A
Authority: US
Inventors: Carl W Johnson
Original assignee: AMF Inc
Current assignee: AMF Inc
Priority date: 1956-05-07
Filing date: 1958-01-20
Publication date: 1960-08-16
Anticipated expiration: 1977-08-16

Description

Aug. 16, 1960 C. W. JOHNSON SEWING MACHINE LOOPER MECHANISM Original Filed May 7, 1956 2 Sheets-Sheet l FlG.l

J6 INVENTOR CARL W. JOHNSON 5% BY Z ATT NEY Aug. 16, 1960 c. w. JOHNSON SEWING MACHINE LOOPER MECHANISM 2 Sheets-Sheet 2 Original Filed May '7, 1956 FIG. 2

INVENTOR CARL W. JOHNSON 225v fir'roa EY Unite SEWING MACHINE LOOPER MECHANISM Original application May 7, 1956, Ser. No. 583,027,

now Patent No. 2,900,939, dated Aug. 25, 1959. Divided and this application Jan. 20, 1958, Ser. No.

12 Claims. (Cl. 112-471) The invention relates to sewing machines and more particularly to short thread sewing machines which utilize a double pointed needle having an eye located between the points, and wherein the opposite ends of the needle are grasped alternately by the jaws of opposed needle bars in order to move the needle and thread back and forth through the work in forming stitches.

A machine of the type described above has many uses in the manufacture of articles of clothing such as gloves, mens and womens apparel and novelty collars. In stitching certain types of articles, such for example as collars of mens shirts. it is desirable that the short thread used in the machine be of such a length that the entire collar can be stitched without the necessity of piecing the thread. Otherwise, if it is necessary to piece the thread, which heretofore has required the use of a second thread to continue the formation of stitches, the piecing may show and an unsatisfactory finished product result.

The present invention makes it unnecessary to rethread the needle during the stitching of certain articles, such for example as collars of mens shirts. With the mechanism embodying the invention, a much greater length of thread can be used than was possible in machines available heretofore. The invention therefore results in the production of more satisfactory products and a substantial reduction in time formerly required for rethreading of needles, and stopping and starting of stitching operations because of the need for replacing and piecing the thread.

The invention is characterized by the provision of a sewing machine provided with a novel thread pulling mechanism or looper which pulls the loose end of a short thread through the work with great rapidity, thereby making it possible to use a thread of substantially increased length than heretofore was possible in the art.

It is an object of the invention to provide a novel thread pulling or looper mechanism for use in a short thread sewing machine wherein the construction and operation of the mechanism is such that it is possible to use a much longer thread and thereby improve the appearance of the work and decrease costs because of the substantial reduction in time required to rethread the needle and restart the operation of the machine subsequent to the rethreading.

7 It is also an object of the invention to provide a novel thread handling mechanism including a two revolution thread puller or looper operative to so handle a length of thread that a substantially increased length of thread can be used in the machine.

With these and other objects not specifically mentioned in view, the invention consists in certain combinations and constructions which will be hereinafter fully described, and then set forth in the claims hereunto ap pended.

In the accompanying drawings which form a part of this specification, and in which like characters of reference indicate the same or like parts:

a Fig. 1 is a sectional side elevation of an under and States Patent e .QCF

over stitch sewing machine provided with a preferred form of looper operating mechanism embodying the invention, and

Fig. 2 is a partial front elevation of the mechanism shown in Fig. 1.

This application is a division of my copending application, Serial No. 583,027, filed May 7,1956, now Patent No. 2,900,939, issued Aug. 25, 1959 Referring to the drawings, there is disclosed apparatus constructed in accordance with the invention, and embodied in a sewing machine which may be similar in construction and operation to that illustrated and described in Johnson Patent 2,386,800, granted October 16, 1945.

The sewing machine is driven through a belt 10 running on pulley 12 secured to hub 14 of gear 16 rotatably supported on a headed stud 18 attached by suitable screws 22 to the machine frame 20. Belt 10 is driven by a pulley (not shown) which is integral with a suitable clutch mechanism (not shown) driven from a motor (not shown) in a manner similar to that disclosed in Patent No. 2,368,066 issued to C. W. Johnson January 23, 1945. Since the drive, as well as the mechanism for operating the clutch and brake form no part of the present invention, further showing and description thereof are omitted.

'A cam 24 preferably formed integrally with pulley 12 is provided with a cam track 26 in which run cam rollers 28 and 30 positioned at diametrically opposite points of cam 24. Cam roller 28 is pivotally attached to a cam lever 32 projecting from the rear end of an elongated hub or sleeve 34 pivotally mounted on horizontal shaft 36 held at one end by a suitable bearing bracket 38 and at the other end by another suitable bearing lug 40. Cam roller 30 is pivotally attached to a cam lever 42 which projects rearwardly from an end of an elongated hub or sleeve 44 loosely supported on a suitably mounted horizontal shaft 46.

The machine is provided with an upper needle bar 48 and a lower needle bar 50, both vertically positioned and arranged in axial alignment. Each needle bar carries an actuating

member

52 and 54 respectively. Actuating member 52 of the upper needle bar 48 engages with a shoe or roller 56 pivotally mounted on an actuating arm 58 projecting from the forward end of sleeve 34. Actuating member 54 of the lower needle bar 50 engages with a roller 60 pivotally attached to the free end of an actuating arm 6'2 projecting from the forward end of sleeve 44. Since the actuating

members

52 and 54 of the upper and lower needle bars, respectively, are of the sliding block type, oscillating motion imparted to actuating arms 58 and 62 and sleeve members 34 and 44 by cam 24 through cam levers 32 and 42, respectively, is converted into vertical reciprocating motion of needle bars 48 and 50 which are guided in suitable bushings in

guide lugs

64 and 66, respectively.

Needle N, which is moved back and forth through the work by needle bars 48 and 50, is provided with a pointat each end and an eye through which the thread passes, located preferably about midway therebetween. Since both needle bars 48 and 50 are constructed in the same manner as the needle bars shown and described in Patent 2,386,800, a detailed description thereof is deemed unnecessary and is omitted in the present case. understood by those skilled in the art that in this type of machine, needle N is grasped alternately by the jaws of each needle bar as the needle is pushed vertically downward or upward through the work of material M (Fig. 2).

on its upper free end carries a thread engaging head 72 It will be so mounted that it may rotate around the periphery of a stationary thread drum 74 which is suitably secured to a frame portion of the machine. The chief function of the thread puller is to engage with its head '72 the loop L of the thread on alternate movements of the needle N and pull the loose end of the thread through the work or material over upper looper 75 movably mounted above the work supporting table T (Fig. 2), and dispose it about the periphery of the drum 74 in such a manner that the danger of snarling, fouling or breaking the thread is practically eliminated. Thread puller head '72, upper looper 75, the work feeding means (not shown), and drum 74 are similar in construction and operation to those shown in Johnson Patent 2,368,066, and since they form no specific part of the invention, further detailed showing and description thereof are omitted.

Since the loose end of the thread has to be pulled through the work and deposited upon drum 74 before the needle N can be pushed upwardly again through the work by the lower needle bar, the length of the thread that can be used is determined by the speed with which the above mentioned loose end can be pulled through the work by the thread puller.

Figs. 1 and 2 disclose a stitching machine provided with a preferred embodiment of thread puller or looper 68 and operating mechanism therefor. Thread puller 68 is revolved about drum 74 twice during one cycle of the machine, instead of only once, as in the machine disclosed in the above referred to Johnson patents. Due to the number of revolutions of thread puller 63, a substantially longer length of thread can be used because of the novel manner in which the loose end is pulled through the work and disposed on drum 74 out of the path of travel of needle N.

In order to avoid interference with the upward moving lower needle bar 50 as thread puller 68 passes the latter during its second revolution, means are provided to move thread puller 68 laterally during a portion of its revolving movement to prevent such undesirable interference.

Thread puller arm 70, shown in Figs. 1 and 2, is mounted on one end of a horizontal shaft 76, to the other end of which is secured a gear 78. Shaft 76 also carries a sleeve member 80 loosely mounted thereon and extending from the face of the hub of arm 70 to the face of the hub of gear 78 (Fig. l). Sleeve member 30 in turn is slidingly supported by a suitable bearing bracket 82 secured to a frame portion of the machine. The comparatively narrow gear 78, which is mounted on and rotates shaft 76, meshes with a wide gear 84 loosely mounted on horizontal stud shaft 36 mounted on a suitable frame portion of the machine. Gear 64 also meshes with and is driven by gear 88 loosely mounted on stud shaft 90 mounted on a suitable frame portion of the machine. Gear 88 preferably is integral with a

gear

92 and 94, the latter of which through a suitable gear train 96, is connected with and driven by gear 16 mentioned heretofore. By means of the gear arrangement illustrated, gear 78 and shaft 76 are rotated two revolutions for each single revolution of gear 88.

The lateral displacement of arm 70 for the purposes described, is accomplished by means of a cam lever 98. The upper free end of lever 98 is pivotally attached to one end of sleeve member 80 while the lower end of cam lever 98 is loosely supported on stud held by bracket 102. attached to a frame portion of the machine. Cam lever 98 carries a cam roller 104 which runs in a track 105 in a suitable cam 106 formed integrally with the hub of gear 8- which, as mentioned above, drives gear 78 on the shaft 76 which carries thread puller arm 70. It will be seen that every time cam roller 104 runs on the high portion 167 of cam track 105, cam lever 98 moves the sleeve member in a horizontal direction to the left, as viewed in Fig. l, which in turn also effects a lateral displacement of the shaft 76 and consequently a movement of the thread puller arm 70 away from needle bar 4 50. For better dynamic balance, the arm 70 is provided with a counter-balance arm 108.

In a short stitch sewing machine provided with thread pullers or loopers construction in accordance with the invention, it is possible to use a thread having a length up to twenty percent (20%) greater than has been possible heretofore in the art. It will be seen, therefore, that the invention contributes not only to improved appearance in goods stitched on a machine provided with the invention, but also the machine can be operated for longer periods of time without rethreading.

What I claim is:

1. In a sewing machine, the combination with a needle and opposed needle bars, of means for alternately connecting said needle with said bars and projecting said needle with a thread having a fixed end and a loose end through work to be stitched, a drum located adjacent one of said bars, a thread puller device co-operating with said drum to pull the loose end of said thread through the work and lay it on said drum, driving means for operating said needle bars at a predetermined normal cyclical rate of speed, and mechanism for rotating said thread puller, said mechanism including means for revolving said thread puller through a plurality of revolutions during each thread pulling operation, whereby the loose end of said thread is pulled rapidly through said work and disposed on said drum.

2. In a sewing machine, a work support table, needle operating mechanism for passing a double pointed needle having an eye located between its points back and forth through work moved over said support table, means for supporting a portion of a length of thread having a loose end and threaded through the eye of said needle above said work, a thread support surface, a thread puller for engaging loops formed in said thread below said work and for pulling the loose end of said thread through said work and laying it on said support surface, a shaft supporting said thread puller, means for operating said needle operating mechanism, and mechanism for rotating said shaft, said mechanism including means for rotating said thread puller through two revolutions subsequent to its engagement with each loop of thread whereby said loose end of said thread is pulled rapidly through said work and disposed on said support surface.

3. In a sewing machine, a work support table, needle operating mechanism for passing a double pointed needle having an eye located between its points back and forth through work moved over said support table, means for supporting a portion of a length of thread having a loose end and threaded through the eye of said needle above said work, a thread support surface, a thread puller for engaging loops formed in said thread below said work and for pulling the loose end of said thread through said work and laying it on said support table, a shaft supporting said thread puller, means for operating said needle operating mechanism, means for rotating said shaft at a rate of speed to travel through two revolutions subsequent to its engagement with each loop of thread, and means for moving said thread puller laterally during a portion of each two revolution travel thereof for preventing its striking said needle operating mechanism.

4. In a sewing machine, the combination with a needle and opposed upper and lower needle bars, of means for alternately connecting said needle with said bars and projecting said needle with a relatively long length of thread having a fixed end and a loose end through work to be stitched, a work support table, a thread receiving surface located beneath said table and adjacent one of said bars, a rotatable thread puller device located beneath said table and cooperating with said surface to engage a loop of thread formed by the upward movement of said lower needle bar and pull the loose end of said thread through the work and lay it on said surface, driving means for operating said needle bars in a predetermined normal cyclical rate of speed, and mechanism for rotating said thrgad puller about said surface, said mechanism including means for rotating said thread puller through two revolutions for each upward movement of said lower needle bar, whereby said loose end of said thread is pulled rapidly through said work and disposed on said drum.

5. The invention defined in claim 4 wherein mechanism is provided for displacing said thread puller laterally relative to said lower needle bar to prevent its striking said lower needle bar as said thread puller travels, through its second revolution.

6. The invention defined in claim 5 wherein said mechanism includes a shifting lever, means connecting said lever .to said thread puller, a cam fol-lower on said lever and a cam engaged by said cam follower for displacing said thread puller.

7. The invention defined in claim 4 including a movable mount for said thread puller, and means for moving said mount to displace said thread puller laterally out of the path of said lower needle bar as said thread puller moves into the range of operation of said lower needle bar on its second revolution.

8. In a sewing machine, the combination with a needle and opposed upper and lower needle bars, of means for alternately connecting said needle with said bars and projecting said needle with a relatively long length of thread having a fixed end and a loose end through work to be stitched, a work support table, a thread receiving surface located beneath said table and adjacent one of said bars, a movable thread supporting device located adjacent said upper needle bar, a rotatable thread puller device located beneath said table and cooperating with said surface to engage a loop of thread formed by the upward movement of said lower needle bar and pull the loose end of said thread over said thread supporting device, through the work and lay it on said surface, driving means for operating said needle bars in a predetermined normal cyclical rate of speed, and mechanism for rotating-said thread puller about said surface, said mechanism including means for rotating said thread puller through two revolutions for each upward movement of said lower needle bar, whereby said loose end of said thread is gulled rapidly through said work and disposed on said rum.

9. In a sewing machine, the combination with a needle and opposed upper and lower needle bars, of means for alternately connecting said needle with said bars and projecting said needle with a relatively long length of thread having a fixed end and a loose end through work to be stitched, a work support table, a thread receiving surface located beneath said table and adjacent one of said bars, a movable thread supporting device located adjacent said upper needle bar, a rotatable thread puller device located beneath said table and cooperating with said surface to engage a loop of thread formed by the upward movement of said lower needle bar and pull the loose end of said thread over said thread supporting device, through the work and lay it on said surface, driving means for operating said needle bars in a predetermined normal cyclical rate of speed, means for rotating said thread puller about said surface through two revolutions for each upward movement of said lower needle bar, whereby said loose end of said thread is pulled rapidly through said work and disposed on said drum, and means for moving said thread puller away from said lower needle bar as it approaches and moves past said lower needle bar on each second revolution of movement.

10. In a sewing machine, a work support table, needle operating mechanism including an upper needle bar and an axially aligned lower needle bar for passing a double pointed needle having an eye located between its points back and forth through work moved over said support table, means for supporting a portion of a length of thread having a loose end and threaded through the eye of said needle above said work, a thread supporting surface, a thread puller for engaging loops formed in said thread below said work by the upward movement of said lower needle bar and for pulling the loose end of said thread through said work and laying it on said support table, a shaft supporting said thread puller, means for operating said needle operating mechanism, means for rotating said shaft at a rate of speed in excess of the speed of operation of said needle operating mechanism for at least a part of its movement whereby said loose end of said thread is pulled rapidly through said work and disposed on said surface, and means for moving said thread puller laterally out of the path of movement of said lower needle bar during a part of the travel of said thread puller in laying said loose end of said thread on said surface.

11. In a sewing machine, a work support table, needle operating mechanism including an upper needle bar and an axially aligned lower needle bar for passing a double pointed needle having an eye located between its points back and forth through work moved over said support table, means for supporting a portion of a length of thread having a loose end and threaded through the eye of said needle above said work, a thread supporting surface, a thread puller for engaging loops formed in said thread below said work by the upward movement of said lower needle bar and for pulling the loose end of said thread through said work and laying it on said support table, a shaft supporting said thread puller, means for operating said needle operating mechanism, means for rotating said shaft at a rate of speed in excess of the speed of operation of said needle operating mechanism for at least a part of its movement whereby said loose end of said thread is pulled rapidly through said work and disposed on said surface, and means for eifecting relative lateral movement between said thread puller and said lower needle bar as said thread puller approaches and moves past said lower needle bar during a portion of the movement of said thread puller in pulling said loose end of said thread through said work, whereby said thread puller may dispose said loose end of said thread on said drum without striking said lower needle bar.

12. In a sewing machine, a work support table, needle operating mechanism for passing a double pointed needle having an eye located between its points back and forth through work moved over said support table, means for supporting a portion of a length of thread having a loose end and threaded through the eye of said needle above said work, a thread support surface, a thread puller for engaging loops formed in said thread below said work and for pulling the loose end of said thread through said work and laying it on said support surface, a shaft supporting said thread puller, means for operating said needle operating mechanism, means for rotating said shaft at a rate of speed to travel through two revolutions subsequent to its engagement with each loop of thread, and means for moving said thread puller along a different path of travel relative to said support surface during a portion of each two revolution travel thereof for preventing its striking said needle operating mechanism.

References Cited in the file of this patent UNITED STATES PATENTS 515,713 Miller Feb. 27, 1894 1,786,621 Lawson Dec. 30, 1930 2,386,800 Johnson Oct. 16, 1945