US2172494A - Blind stitch sewing machine - Google Patents

Description

p 12, 1939- L. G. BOWMAN BLIND STITCH SEWING MACHINE 5 Sheets-Sheet 1 Filed Dec. 28, 1936 Ema/whom $0018 6?. Bowman Sept. 12, 1939. L g BOWMAN 2,172,494

BLIND STITCH SEWING MACHINE F'ild Dec. 28; 1936 5 Sheets-Sheet 2 1:: a -EM p 1939- L. G. BOWMAN BLIND STITCH SEWING'MACHINE 5 Sheets-Sheet 4 .Filed Dec. 28, 1936 Sept. 12, 1939. G. BOWMAN BLIND STITCH SEWING MACHINE Filed Dec. 28, 19:56 I 5 Sheets-Sheet 5 Louis 6:. Bowman Patented Sept. 12, 1939 UNITED STATES PATENT OFFICE v BLIND STITCH SEWING MACHINE Application December 28, 1936, Serial No. 117,940

34 Claims.

This invention relates to new and useful improvements in blind stitch sewing machines generally, although more particularly to blind stitch machines of the single thread chain stitch type adapted especially for hemining operations.

It is a well known fact that if the last formed needle thread loop in the stitched seam is not locked, the entire line of stitches may be pulled out accidentally.

Among the several objects of my invention are to provide means for severing the thread whereby when the seamed article is removed from the machine the last formed needle loop in the seam will be locked by the trailing end of the thread; to provide such severing means which will also function to pull off thread from the supply; to provide a clamp for clamping the supply end of the thread adjacent the point of severance whereby when the machine is again operated the stitch forming mechanism will immediately function, and to provide means for operating the thread severing means upon depression of the work support.

With these and other objects in view which will more fully appear, the nature of the invention will be more clearly understood by following the description, the appended claims, and the several views illustrated in the accompanying drawings.

In the drawings Figure 1 is a front elevation of a blind stitch sewing machine embodying my invention,

Figure 2 is a top plan view thereof,

Figure 3 is an enlarged section showing the thread carrier and the actuating means therefor in their normal positions,

Figure 4 is a similar View but showing the thread carrier and the actuating means therefor in their operative positions,

Figure 5 is an enlarged detail plan View showing the presser foot, the needle, the looper, the stitched fabric, and the thread carrier,

Figure 6 is a plan View of the completed seam showing the last formed needle thread loop locked by the trailing end of the thread,

Figures 7, 8 and 9 are views of the thread clamp and stationary knife, and

Figure 10 is a perspective view of the thread carrier.

Like reference numerals designate corresponding parts throughout the several figures of the drawings.

My invention is adapted especially for joining a hem A to a body fabric B by a line of blind stitches of the single thread chain stitch type, as

shown in Figure 6. A needle thread 0 is employed to form the stitches and the needle loops 0 are spaced equidistantly apart, and the connecting portions of the thread between the loops are arranged in a straight line and in parallelism to the inner edge a of-the hem.

The machine to which my invention is applied is disclosed in Patent 2,030,751, issued to Joseph Mann on Feb. 11, 1936, and includes a main frame comprising a base 5 having a standard 6 projecting from the rear right hand corner thereof, an arm I which extends laterally from the upper end of the standard, and an arm 8 which extends forwardly from the left hand end of the arm 1. Fixed to the free end of the arm 8 is a horizontal presser foot 9 having a centrally located and longitudinally extending opening l0 therein. The foot is attached at its rear end to the arm by a screw II, and the front portion of the foot is held against flexing by spaced posts l2, [3 which are connected to the opposite sides of the foot and to the arm. J ournaled in the arm 1 of the frame is a main shaft I4, the left hand end thereof projecting across the rear end of the arm 8. Journaled in the arm 8 and extending longitudinally thereof is an oscillatory needle shaft l5 which is driven from the main shaft by the usual connections. The needle shaft I5 is disposed directly above the opening H) in the foot, and fixed to the outer end of the shaft is a needle arm l6 carrying a curved needle ll. Thus when the needle shaft is oscillated the needle will reciprocate transversely across and above the opening ID in the presser foot. It will be noted that the penetrating stroke of the needle, as viewed from the front of the machine, is from right to left. Rigid with the base 5 are posts l8 which are located in a plane in advance of the standard 6 and a work support I9 is pivotally supported as at l9a on the upper ends of these posts and includes a lateral extension 20 which projects under the presser foot 9, and an arm I92: which projects rearwardly beyond the pivot [9a, the work support being yieldably held against depression by a spring 2|. An adjustable screw I9c is threaded into the rearwardly extending arm l9b for engagement with a part of the machine frame for variably limiting the upward movement of the work support. A reciprocatory ridge forming element R which in the present machine is shown as a disc, is provided for projecting nodes of fabrics upwardly through the opening H3 in the foot into needle penetrating position. This disc R is fixed to a rock shaft 22 journaled on the underside of the ated in the usual manner from the main shaft M. In order to form the line of single thread chain stitches, I employ a complemental stitch forming mechanism which cooperates with the needle I1 and includes a loop taker 'X. This loop taker is in the form of a non-thread carrying looper having an arcuate beak 21 and an' at- I taching shank 28, the latter being secured to a holder 29 by a clamp screw 38. The holder 29 is clamped by a screw 3| to the lower end of a vertically disposed rock shaft 32 which is journaled in a bracket 33 attached to the forward end of the frame arm 8 by screws 34, the shaft 32 and the loop taker X being located above the presser foot 9 and at the left of the opening ||l therein. The shaft 32 is also disposed in front of the vertical plane containing the path of needle recipv rocations. The beak 21 of the loop taker extends rearwardly relative to the shank 28 and oscillates in a horizontal plane above the needle l8.

. end of the looper shaft 32 is a rearwardly extending rock arm 35 and-pivotally connected to the rear end thereof is one end of a link 31, the other end'of said link beingconnected to the upper end of a rock arm 38 fixed t0 the needle shaft i5. Fixed to the presser foot 9 by a screw 39 is a thread loop abutment 40 which is located intermediate the looper X and the left hand wall of the opening I0, and the forward end 4| of the abutment being located at a point slightly in rear of the vertical plane. containing the path of needle travel.

In operation of the machine as thus far described, the machine is loaded in the usual manner by first depressing the work support l9 and inserting the body fabric A and hem B under the presser foot 9, the body fabric extending to the left of the hem, whereby the needle l8 will enter the hem and have its penetrating or forward movement towards the inner edge of the hem. The needle after passing through the hem will then enter and emerge from the upper face of the body fabric at a point under the hem and in spaced relation to the inner edge thereof. As the needle begins to recede, it casts out the usual needle thread loop and the beak of the looper will then enter said loop. As soon as the needle point is withdrawn from the hem, the fabric will be fed rearwardly a stitch length distance, and during this time the looper will complete its rearward or loop taking movement and the needle loop which is around the looper will be fed rearwardly against the forward end 4| of the abutment 49 which functions to maintain the needle loop in open relation and in the proper position to be entered by the needle on its next forward stroke.

As previously stated, my invention is applied to the above described blind stitch machine, and functions (1) to cut'the leg 0 of the needle thread C whereby when the work support is depressed and the hemmed fabric is withdrawn from the the next stitching operation, and (3) to clamp the supply thread at the cut end thereof until two or more stitches have been formed in said next stitching operation.

a To this end, I have provided a thread cutting mechanism which includes a stationary knife D iandra cooperating movable thread carrier E which are located above the presser foot .9. The

knife D isformed. from a thin strip of metal and includes an attaching arm 42 and a blade 43 arranged in planes at right angles to each other, the lower edge of the blade being sharpened as indicated at 44. The arm 42 is located immediately in rear of the vertical plane containing the path of travel of the needle, and is secured to the attaching arm 45 of a thread clamp F by a screw 46, and the attaching arm '45 is secured to the front end of the frame arm 8 by screws 41, the blade'43 extending rearwardly and being located at the right of the presser foot opening l0, and the sharpened edge 44 being located above and in spaced relation to the foot.

The thread clamp or nippers F includes a downwardly extending and relatively rigid front arm 48 which is preferably integral with the attaching arm 45, and a relatively flexible rear arm 49 disposed in rear of and in parallelism with the front arm 48 and secured at its upper end thereto by a screw 58. The lower end of the front arm is curved forwardly as at 5| and cooperates with the lower end of the rear arm 49 to form a resultant thread receiving throat 52 which is,

located at the right of the presser foot opening l0 and directly above the leg 0 of the needle 0 which is around the looper X when the needle is at the rear end of its stroke.

The thread carrier E is mounted on the presser foot and is movable upwardly to engage the leg 0 of the thread and elevate the same into the thread clamp F and then into cutting cooperation with the knife D, whereby (1) thread will be pulled from the supply, (2) the supply end of the leg 0 of the thread will be clamped, and (3) the leg 0 will be severed. The thread. carrier E comprises a rock arm 53 which is prefere ably constructed integral with a rock shaft 54, and the outer end of the arm is forked to form resultant spaced thread supporting arms 55, 55 and an inwardly extending slot 56 therebetween, the upper faces of the arms adjacent their outer ends being provided with recesses or seats 51, 51, and the slot being disposed in vertical alinement with the blade 43 of the stationary knife D. I

A horizontal bearing plate 58 is attached by screws 59 to the upper face of the presser foot on the right hand side of the opening I0 and in rear of thepath of movement of the needle. The

plate is provided with spaced transverse bearrock shaft 54, and is normally positioned in a longitudinally extending slot 65 formed in the presser foot 9 on the right of the slot Ill therein. A coil spring 66 has one end connected to an upwardly extending rock arm 61 fixed to the rock shaft 54 intermediate the bearings 60, 6! and has its other end fixed to an anchor plate 68 attached to the right hand post 13 of the presser foot. The spring functions to yieldably retain the thread carrier arm 53 in its normal position within the slot 65, the downward movement of the arm being stopped by the arm contacting the foot at the rear end of the slot. Thus, when the rock arm 63 is depressed, the thread carrier arm 53 will be elevated against the tension of the spring 56, and the carrier arms 55, 55 will be positioned on opposite sides of the blade 43 of the stationary knife D.

It is desirable to actuate the thread carrier E immediately prior to the stitched article being removed from the machine in order to effect a locking of the needle loop of the last formed stitch. To this end, I have provided means for actuating the carrier E upon depression of the work support. For this purpose, a vertical arm 6.: is rigidly connected to the left side of the rearwardly extending arm l9b of the work support and at a point adjacent the lateral arm I of the main frame. A horizontal arm Ill which is fixed to the upper end of the arm 69, is disposed in parallelism with the lateral arm 1 and terminates at its free end in spaced relation to the forwardly extending frame arm 8 at a point in rear of the rock arm 63. A bearing arm H is attached to the frame arm 8 intermediate the horizontal arm 10 and the rock arm 63, and a lever 12 extends in parallelism with the frame arm 8 and is fulcrumed intermediate its ends as at 13 on said bearing arm H. The forward end of the lever 12 carries a laterally extending pin M which overlies the rock arm 63 and the rear end of the lever overlies the free end of the horizontal arm in. The lower rear edge of the lever is cut away as at 15 to permit the arm Hi to continue its forward and upward movement after the thread carrier arm 53 has been elevated to its operative position with respect to the stationary knife D, without imparting unnecessary additional movement to said thread carrier arm, as shown in Figure 4.

In operation, after a hem has been seamed, the machine is stopped with the needle at the be ginning of its stroke, the work support 59 is then. depressed by a treadle or knee-press which is connected thereto in the usual manner, and the seamed hem is then withdrawn from the machine. During the depression movement of the work support, the horizontal arm H! which is mounted on the rear extension 58b thereof, is elevated and raises the rear end of the lever !2 which is fulcrumed on the frame arm 8. The downward movement of the front end of the lever swings the rock arm 63 downwardly and this effects the elevation of the thread carrier arm 53 to raise the leg 0 of the needle thread loop which is around the looper into the throat 52 and then between the clamping or nipping arms 5&3, of the thread clamp F. The carrier arm 53 moves upwardly between the looper and the thread clamp F, and after the thread has been nipped by the clamp, it is moved upwardly into cooperative relation with the stationary knife and there severed. It will be observed that a long length of trailing thread is thus privided where by when the stitched hem is withdrawn from the machine, the last formed needle loop will be locked and the length of said trailing thread will suffice to prevent the same from being accidenta1- ly withdrawn from said loop. After the thread has been thus severed, the supply end of the thread will remain in the clamp F until after at least two stitches have been formed in the next stitching operation, the retention of this supply end of the thread by the clamp insuring the formation of stitch during the first forward travel of the needle. I

It will be also observed that inasmuch as the thread supply is anchored by reason of the needle thread loop extending around the looper, the upward movement of the carrier arm 53 will pull off from the supply a sufficient amount of thread which will be retained by the thread clamp until two 01' more stitches have been formed in the next seaming operation.

It is of course to be understood that the details of structure and arrangement of parts may be variously changed and modified without deand the needle when the latter is at the beginning of its forward stroke to sever the leg of the needle thread loop extending around the looper.

2. In a single thread blind stitch sewing machine, the combination with a stationary presser foot having an opening therein, of a threaded needle located above the foot for reciprocatory movements across the opening thereof, a nonthread-ed looper located above the foot for co operation with said needle, a ridge forming element for projecting a ridge of fabric upwardly through the opening into needle penetrating position, a stationary knife located above the foot and between the looper and the needle when the latter is at the beginning of its stroke, and a manually operable carrier for raising the leg of the needle loop ext-ending around the looper into cooperative cutting relation with said knife.

3. In a single thread blind stitch sewing machine, the combination with a stationary presser foot having an opening therein, of a threaded needle located above the foot for reciprocatory movements across the opening thereof. a nonthreaded looper located above the foot for cooperation with said needle. a ridge forming element for projecting a ridge of fabric upwardly through the opening into needle penetrating position, a stationary knife located above the foot and between the looper and the needle when the latter is at the beginning of its stroke, and a manually operable carrier for raising the leg of the needle loop extending around the looper into cooperative cutting relation with said knife, said carrier comprising an arm fulcrumed on the presser foot in rear of the needle path and having its forward end normally disposed under said leg of said needle loop, the free end of the arm being slotted to form resultant thread sup- 75 knife.

4. In a single thread blind stitch sewing machine, the combination with a stationary presser foot having an opening therein, of a threaded needle located above the foot for recip-rocatory movements across the opening thereof, a nonthreaded looper located above the foot for co operation with said needle, a ridge forming element for projecting a ridge of fabric upwardly through the opening into needle penetrating position, a stationary knife located above the foot and between the looper. and the needle when the latter is at the beginning of its stroke, and a manually operable carrier for raising the leg of the needle loop extending around the looper into cooperative cutting relation with said knife, said carrier comprising an arm fulcrume-d on the presser foot in rear of the needle path and having its forward end normally disposed under said leg of said needle loop, the free end of the arm being slotted to form resultant thread supporting arms movable to opposite sides of the knife,

the upper faces of the arms being recessed to form thread seats. 7

5. In a single thread blind stitch sewing machine, the combination with a stationary presser foot having an opening therein, of a threaded needle located above the foot for reciprocatory movements across the opening thereof, a nonthreaded looper located above the foot for cooperation with said needle, a ridge forming element for projecting a ridge of fabric upwardly through the opening into needle penetrating position, a stationary'knife located above the foot and between the looper and the needle when the latter is at the beginning of its stroke, and a manually operable carrier for raising the leg of the needle loop extending around the looper into cooperative cutting relation with said knife, said carrier comprising an arm fulcrumed on the presser foot in rear of the needle path and having its forward end normally disposed under said leg of said needle loop, means for yieldably retaining the carrier arm against upward move ment, and manually operable means for raising the carrier arm against the tension of said yieldable means.

6. In a single thread blind stitch sewing machine, the combination with a stationary presser foot having an opening therein, of a threaded needle located above the foot for reciprocatory movements across the opening thereof, a nonthreaded looper located above the foot for cooperation with said needle, a ridge forming element for projecting a ridge of fabric upwardly through the opening'into needle penetrating position, a thread clamp located between the looper and the needle when the latter is at the beginning of its forward stroke,,a thread cutting knife, and means located between the thread clamp and the looper for first positioning the leg of the needle loop extending around the looper into the thread clamp and for subsequently moving said threadinto severing relation with said knife.

'7. In a single thread blind stitch sewing machine, the combination with a stationary presser foot having an opening therein, of a threaded needle located above the foot for reciprocatory movements across the openingthereof, a nonthreaded looper located above the foot for cooperation with said needle, a ridge forming element for projecting a ridge of fabric upwardly through the opening into needle penetrating position, a

thread clamp located between the looper and the needle when the latter is at the beginning of its forward stroke, a thread cutting knife and means located between the thread clamp and the looper for first positioning the leg of the needle loop extending around the looper into the thread clamp and for subsequently moving said thread into severing relation with said knife, said clampv chine, the combination with a stationary presser foot having an opening therein, of a threaded needle'located above the foot for reciprocatory movements across the opening thereof, a non threaded looper located above the foot for cooperation with said needle, a ridge forming element for projecting a ridge of fabric upwardly through the opening into needle penetrating position, a thread clamp located between the looper and the needle when the latter is at the beginning of its forward stroke, a thread cutting knife, andlmeans located between the thread clamp and the looper for first positioning the leg of the needle loop extending around the looper into the thread clamp and for subsequently moving said thread into severing relation with said knife, said positioning means comprising a carrier arm fulcrumed on the presser foot in rear of the needle path and having its forward end normally disposed under said leg of the needle loop.

9. In a single thread blind stitch sewing machine, the combination with a stationary presser foot having an opening therein, of a threaded needle located above the foot for reciprocatory movements across the opening thereof, a nonthreaded looper located above the foot for cooperation with said needle, a ridge forming element for projecting a ridge of fabric upwardly through the opening into needle penetrating position, a thread clamp located between the looperand the needle when the latter is at the beginning of its forward stroke, a thread cutting knife, and means located between the thread clamp and the looper for first positioning the leg of the needle loop extending around the looper into the thread clamp and for subsequently moving said thread into severing relation wth said knife, said positioning means comprising a carrier arm fulcrumed on the presser foot in rear of the needle path and having its forward end normally disposed under said leg of the needle loop, means foryieldably retaining thecarrier arm against upward movement, and manually operable means for raising the carrier arm against the tension of said yieldable means.

10. In a single thread blind stitch sewing machine, the combination with a stationary presser foot having an opening therein, of a threaded needle located above the foot for reciprocatory movements across the opening thereof, a nonthreaded looper located above the foot for cooperation with said needle, a ridge forming element for projecting a ridge of fabric upwardly through the opening into needle penetrating position, a thread clamp located between the looper and the needle when the latter is at the beginning of its clamp and the looper for first positioning the leg of the needle loop extending around the looper into the thread clamp and for subsequently cooperating with the knife in severing said thread,

said last named means including a carrier arm fulcrumed on the presser foot in rear of the needle path and having its forward end normally disposed under said leg of the needle loop, the free end of the arm being slotted to form resultant thread supporting arms movable to opposite sides of the knife, means for yieldably retaining the carrier arm against upward movement, and manually operable means for raising the carrier arm against the tension of said yieldable means.

11. In a single thread blind stitch sewing machine, the combination with a stationary presser foot having an opening therein, of a threaded needle located above the foot for reciprocatory movements across the opening thereof, a nonthreaded looper located above the foot for cooperation with said needle, a ridge forming element for projecting a ridge of fabric upwardly through the opening into needle penetrating position, a thread clamp located between the looper and the needle when the latter is at the beginning of its forward stroke comprising vertically disposed clamping arms forming a resultant thread receiving throat at their lower end and located directly above said leg of the needle loop, a thread cutting knife, and means located between the thread clamp and the looper for first positioning the leg of the needle loop extending around the looper into the thread clamp and for subsequently moving said thread into severing relation with said knife, said positioning means comprising a carrier arm fulcrumed on the presser foot in rear of the needle path and having its forward end normally disposed under said leg of the needle loop.

12. In a single thread blind stitch sewing machine, the combination with a stationary presser foot having an opening, a threaded needle located above the foot for reciprocations transversely across the presser foot opening, a ridge forming element for projecting a ridge of fabric upwardly through the opening into needlepenetrating position, means for feeding the fabric to the needle, a non-threaded looper located above the foot and operating entirely on the side of the ridge forming element opposite the point of needle penetration in the fabric for engaging the needle thread loop and holding the same for re-entrance by the needle, and thread severing means operative above the foot and between the looper and the needle when the latter is at the beginning of its stroke.

13. In a single thread blind stitch sewing machine, the combination with a stationary presser foot having an opening, a threaded needle located above the foot for reciprocations transversely across the presser foot opening, a ridge forming element for projecting a ridge of fabric upwardly through the opening into needle penetrating position, means for feeding the fabric to the needle, a non-threaded looper located above the foot and operating entirely on the side of the ridge forming element opposite the point of needle penetration in the fabric for engaging the needle thread loop and holding the same for re-entrance by the needle, a stationary knife located above the foot and between the looper and the needle when the latter is at the beginning of its stroke, and a manually operable carrier arm for raising the leg of the needle loo-p extending around the looper into cooperative cutting relation with said knife.

14. In a single thread blind stitch sewing machine, the combination with a stationary presser foot having an opening, a threaded needle located above the foot for reciprocations transversely across the presser foot opening, a ridge forming element for projecting a ridge of fabric upwardly through the opening into needle penetrating position, means for feeding the fabric to the needle, a non-threaded looper located above the foot and operating entirely on the side of the ridge forming element opposite the point of needle penetration in the fabric for engaging the needle thread loop and holding the same for re-entrance by the needle, said looper being supported for oscillatory movements about a vertical axis and including a curved beak movable in a horizontal plane, and thread severing means operative above the foot and between the looper and the needle when the latter is at the beginning of its stroke.

15. In a single thread blind stitch sewing machine, the combination with a stationary presser foot having an opening, a threaded needle located above the foot for reciprocations transversely across the presser foot opening, a ridge forming element for projecting a ridge of fabric upwardly through the opening into needle penetrating position, means for feeding the fabric to the needle, a non-threaded looper located above the foot and operating entirely on the side of the ridge forming element opposite the point of needle penetration in the fabric for engaging the needle thread loop and holding the same for reentrance by the needle, a stationary knife located above the foot and between the looper and the needle when the latter is at the beginning of its stroke, a manually operable carrier arm for raising the leg of the needle loop extending around the looper into cooperative cutting relation with said knife, means for yieldably retaining the carrier arm against upward movement, and manually operable means for raising the carrier arm against the tension of said yieldable means. s

16. In a single thread blind stitch sewing machine, the combination with a stationary presser foot having an opening, a threaded needle located above. the foot for reciprocations transversely across the presser foot opening, a ridge forming element for projecting a ridge of fabric upwardly through the opening into needle penetrating position, means for feeding the fabric to the needle, a non-threaded looper located above the foot and operating entirely on the side of the ridge formingelement opposite the point of needle penetration in the fabric for engaging the needle thread loopand holding the same for re-entrance by the needle, a stationary knife located above the foot and between the looper and the needle when thellatter is at the beginning of its stroke, a manually operable carrier arm for raising the leg of the needle loop extending around the looper into, cooperative cutting relation with said knife, the free end of the arm being slotted to formv resultant thread supporting arms movable to opposite sides of the knife, means for yieldably retaining the carrier arm against upward movement, and manually operable means for raising the carrier arm against the tension of said yieldable means.

17. In a single thread blind stitch sewing machine, the combination with a stationary presser foot having an opening, a threaded needle located above the foot for reciprocations transversely across the presser foot opening, a ridge forming element for projecting a ridge of fabric upwardly through the opening into needle penetrating position, means for feeding the fabric to the needle, a non-threaded looper located above the foot and operating entirely on the side of the ridge forming element opposite the point of needle penetration in the fabric for engaging the needle thread loop and holding the same for re entrance by the needle, a thread clamp located between the looper and the needle when the latter is at the beginning of its forward stroke, a thread cutting knife, and means located between the thread clamp and the looper for first positioning the leg of the needle loop extending around the looper into the thread clamp and for subsequently moving said thread into severing relation with said knife.

18. In a single thread blind stitch sewing machine, the combination with a stationary presser foot having an opening, a threaded needle located above the foot for reciprocations transversely across the presser foot opening, a ridge forming element for projecting a ridge of fabric upwardly through the opening into needle penetrating position, means for feeding the fabric to the needle, a non-threaded looper located above the foot and operating entirely on the side of the ridge forming element opposite the point of needle penetration in the fabric for engaging the needle thread loop and holding the same for reentrance by the needle, a thread clamp located between the looper and the needle when the latter is at the beginning of its forward stroke, a thread cutting knife, and means located between the thread clamp and the looper for first positioning the leg of the needle loop extending around the looper into the thread clamp and for subsequently moving said thread into severing relation with said knife, said clamp comprising vertically disposed clamping arms forming a resultant thread receiving throat at their lower end and located directly above said leg of the needle loop.

19. In a single thread blind stitch sewing machine, the combination with a stationary presser foot having an opening, a threaded needle located above the foot for reciprocations transversely across the presser foot opening, a ridge forming element for projecting a ridge of fabric upwardly through'the opening into needle penetrating position, means for feeding the fabric to the needle, a non-threaded looper located above the foot and operating entirely'on the side of the ridge forming element opposite the point of needle penetration in the fabric for engaging the needle thread loop and holding the same for reentrance by the needle, a thread clamp located between 'the looper and the'needle when the latter is at the beginning of its forward stroke, a thread cutting knife, and means located between the thread clamp and the looper for first positioning the leg of the needle loop extending around the looper into the thread clamp and for subsequently moving said thread into severing relation with said knife, said positioning means 7 comprising a carrier arm fulcrumed on the presser a non-threaded looper located above the foot and operating entirely on the side of the ridge forming element opposite the point of needle penetration in the fabric for engaging the needle thread loop and holding the same for re-entrance by the needle, a thread clamp located between the looper and the needle when the latter is at the beginning of its forward stroke, a thread cutting knife, and means located between the thread clamp and the looper for first positioning the leg of the needle loop extending around the looper into the thread clamp and for subsequently moving said thread into severing relation with said knife, said positioning means comprising a carrier arm fulcrumed on the presser foot in rear of the needle path and having its forward end normally disposed under said leg of the needle loop, means for yieldably retaining the carrier arm against upward movement, and manually operable means for raising the carrier arm against the tension of said yieldable means.

21. In a single thread blind stitch sewing machine, the combination with a stationary presser foot having an opening, a threaded needle located above the foot for reciprocations transversely across the presser foot opening, a ridge forming element for projecting a ridge of fabric upwardly through the opening into needle penetrating position, means for feeding the fabric to the needle, a non-threaded looper located above thefoot and operating entirely on the side of the ridge forming element opposite the point of needle penetration in the fabric for engaging the needle thread loop and holding the same for re-entrance by the needle, a thread clamp located between the looper and the needle when the latter is at the beginning of its forward stroke, a stationary knife located above the foot, and means located between the thread clamp and the looper for first positioning the leg of the needle loop extending around the looper into the thread clamp and for subsequently cooperating with the knife in severing said thread, said last named means comprising a carrier arm fulcrumed on the presser foot in rear of the needle path and having its forward end normally disposed under said leg of the needle loop, the free end of the arm being slotted to form resultant thread supporting arms movable to opposite sides of the knife, means for yieldably retaining the carrier arm against upward movement, and manually operable means for raising the carrier arm against the tension of said yieldable means.

22. In a single thread blind stitch sewing machine, the combination with a stationary presser foot having an opening, a threaded needle located above the foot for reciprocations transversely across the presser foot opening, a ridge forming element for projecting a ridge of fabric upwardly through the opening into needle penetrating position, means for feeding the fabric to the needle, a non-threaded looper located above the foot and operating entirely on the side of the ridge forming element opposite the point of needle penetration in the fabric for engaging the needle thread loop and holding the same for re-entrance by the needle, a thread clamp located between the looper and the needle when the latter is at the beginning of its forward stroke comprisingv vertically disposed clamping arms forming a resultant thread receiving throat at their lower end and located directly above said leg of the needle loop, a thread cutting knife, and means located between the thread clamp and the looper for first positioning the leg of the needle loop extending 23. In a blind stitch sewing machine, the combination with a frame, of a stationary presser foot mounted on said frame and having an opening therein, a stitch forming mechanism mounted on the frame above the foot and including a threaded needle mounted for reciprocations across the opening in said foot, a depressible work support mounted on the frame below the foot, a ridge forming element mounted on the work support for projecting a ridge of fabric upwardly through the opening into needle penerating position, normally inoperative means for severing the needle thread above the foot, and

means for rendering the severing means effective upon depression of the work support.

24. In a blind stitch sewing machine, the combination with a frame, of a stationary presser foot mounted on said frame and having an opening therein, a stitch forming mechanism mounted on the frame above the foot and including a threaded needle mounted for reciprocations across the opening in said foot, and a cooperating loop taker,

' a depressible work support mounted on the frame below the foot, a ridge forming element mounted on the work support for projecting a ridge of fabric upwardly through the opening into needle penetrating position, a thread clamp located between the loop taker and the needle when the latter is at the beginning of its stroke, a thread cutting knife, normally inoperative means for first positioning the leg of the needle thread extending from the needle into the thread clamp and for subsequently moving said thread into severing relation with said knife at a point between the clamp and the fabric being stitched, and means for rendering said positioning and severing means effective upon depression of the work support.

25. In a single thread blind stitch sewing machine, the combination with a frame, of a station'- ary press-er foot mounted on said frame and having an opening therein, a stitch forming mechanism mounted on the frame above the foot and including a threaded needle mounted for reciprocations across the opening in said foot and a cooperating nch-threaded looper, a depressible work support mounted on the frame below the foot, a ridge forming element mounted on the work support for projecting a ridge of fabric upwardly through the opening into needle penetrating position, normally inoperative means for severing the needle thread between the looper and the needle when the latter is at the beginning of its stroke, and means for rendering the severing means operative upon depression of the work support.

26. In a single thread blind stitch sewing machine, the combination with a frame, of a stationary presser foot mounted on said frame and having an opening therein, a stitch forming mechanism mounted on the frame above the foot and including a thread-ed needle mounted for reciprocations across the opening in said foot and a cooperating non-threaded looper, a depressible work support mounted on the frame below the foot, a ridge forming element mounted on the work support for projecting a ridge of fabric upwardly through the opening into needle penetrating position, a thread clamp located between the looper and the needle when the. latter is at the beginning of its stroke, a thread cutting knife, normally inoperative means for Ifirst positioning the leg of the needle thread extending from the needle into the thread clamp and for subsequently moving said thread into severing relation with said knife at a pointbetween the clamp and the fabric being stitched, and means for rendering said positioning and severing means effective upon depression of the work support.

27. .In a single thread blind. stitch sewing'machine, the combination with a frame, of a stationary presser foot mounted on said frame;

and having an opening therein, a stitch forming mechanism mounted on the frame above the foot and including a threaded needle mounted for. reciprocationsacross the opening in said foot and cooperating non-threaded looper, a depressible work support mounted on the frame below the foot, a ridge forming element mounted on the work support for projecting a ridge of fabric. upwardly through the opening into needle penetrating position, a thread clamp located between the looper and the needle when'the latter is at the beginning of its forward stroke, normally inop-' erative .thread severing means located between the looper and the clamp and including a sta tionary knife and a vertically movable carrier arm, and means operableupon depression of the work support for elevating the carrier arm to first position the leg of the needle loop extending around the looper into the thread clamp and for subsequently positioning said thread leg into cooperating cutting relation with said knife.

28; In a blind stitch sewing machine, the combination'with a frame. including a standard and a laterally extending arm, of a horizontal presser foot fixed to the free end of said arm and having. an opening, a stitch formingmechanism mounted. on said arm above the foot and including a threaded needle mounted for reciprocations across the opening in the foot, a depressible work support mounted on the frame and located below said foot, a ridge forming element mounted on the work support for projecting a ridge of fabric upwardly through the opening into needle penetrating position, normally inoperative means for severing the needle thread above the foot, and means for rendering the severing means operative upon depression of the work support.

29. In a blind stitch sewing machine, the com-.

bination with a frame including a standard and a laterally extending arm, of a horizontal presser foot fixed to the free end of said arm and having an opening, a stitch forming mechanism mounted on said arm above the foot and including a threaded needle mounted for reciprocations across the opening in the foot, a pivoted work support mounted on the frame and located below said foot, a ridge forming element mounted on the work support for projecting a ridge of fabric upwardly through the opening into needle penetrating position, a stationary knife mounted on the arm above the foot, a normally inoperative carrier arm supported on the arm below the knife, and connections between the carrier arm and the work support for operating the former upon depression of the latter to elevate the needle thread into cutting relation with said knife.

30. In a blind stitch sewing machine, the combination with a frame including a standard and a laterally extending arm, of a horizontal presser foot fixed to the free end of said arm and having an opening, a stitch forming mechanism mounted on said arm above the foot and including a 8. threaded needle mounted for reciprocations across the opening in the foot, a pivoted work support mounted on the frame and located below forming element mounted on ecting a ridge of fabric,

said foot, a ridge the work support for proj upwardly through the opening into needle penetrating position, a stationary knife mounted on the arm above the foot, a horizontal rock shaft 31. In a blind stitch sewing machine, the combination with a frame including a standard and a laterally extending arm, of a horizontal presser foot fixed to the free end of said arm and having an opening, a stitch forming mechanism mounted on said arm above the foot and including a threaded needle 'mounted for reoiprocations across the opening in the foot, a pivoted work support mounted on the frame and located below said foot, a ridge forming element mounted on the work support for projecting a ridge of fabric upwardly through the opening into needle penetrating position, a stationary knife mounted on the arm above the foot, a horizontal rock shaft journaled on the presser foot, a thread carrier arm fixed to the rock shaft for elevating the needle thread into cutting relation with the knife,

and means for operating the rock shaft upon depression of the work support including a lever fulcrumed on the frame arm and an arm fixed to the work support for operating said lever.

32. In a blind stitch sewing machine, the combination with a frame including a standard and a laterally extending arm, of a horizontal presser foot fixed to the free end of said arm and having an opening, a stitch forming mechanism mounted on said arm above the foot and including a threaded needle'mounted for reciprocations across the opening in the foot, a pivoted work support mounted on the frame and located below said foot, a ridge forming element mounted on the work support for projecting a ridge'of fabric upwardly through the opening into needle penetrating position, a stationary knife mounted on the arm above the foot, a horizontal rock shaft journaled on the presser foot, a thread carrier arm fixed to the rock shaft for elevating the needle thread into cutting relation with the knife, means for yieldably retaining the carrier arm against upward movement, and means for operating the rock shaft against the tension of said yieldable means upon depression. of the work support.

33. In a blind stitch sewing machine, the combination with aframe including a standard and a laterally extending arm, of a horizontal presser foot fixed to the free end of said arm and having an opening, a stitch forming mechanism mounted on said arm above the foot and including a threaded needle mounted for reciprocations across the opening in the foot, a depressible work support mounted on the frame and located below said foot, a ridge forming element mounted on the work support for projecting a ridge of fabric upwardly through the opening into needle penetrating position, a stationary knife mounted on the arm above the foot, a normally inoperative carrier arm supported on the arm below the knife, a thread clamp supported on the frame arm intermediate the knife and the carrier arm, and connections between the carrier arm and the work support for operating the former upon depression of the latter to elevate the needle thread first into the clamp andthen into cutting relation with said knife.

34. In a single thread blind stitch sewing machine, the combination with a frame including a base, a standard, and an arm extending laterally from the upper end of the standard and terminating in a forwardly extending arm, of a horizontal presser foot fixed to the free end of the forwardly extending arm and having an opening therein, a work support pivoted on the base to swing about a horizontal axis in parallelism with the lateral arm and having a forward depressible portion located under .the foot, said work support having a portion extending rearwardly of the pivot, a stitch forming mechanism. mounted on the forwardly extending arm and including a threaded needle mounted for reciprocations across the presser foot opening and a cooperating nch-threaded looper, a stationary knife mounted on said forwardly extending arm above the foot, a rock shaft journaled on the foot, a thread carrier arm fixed to the rock shaft for elevating the leg of the needle loop extending between the looper and the needle into cutting relation with said knife, and means for rocking said shaft upon depression of the work support in-.

cluding a lever fulcrumed on the forwardly extending arm and an arm fixed to the rear portion of the work support for operating said lever.

LOUIS G. BOWMAN.

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