US1955994A - Feed-wheel stop for buttonhole sewing machines - Google Patents

Description

A. R. WOOD April 24, 1934.

FEED WHEEL STOP FOR BUTTONHOLE SEWING MACHINES Filed Dec. 4, 1931 4 Sheets-Sheet l llll gwoantcw Alfred R. Mod.

A. R. WOOD April 24, 1934.

FEED WHEEL STOP FOR BUTTONHOLE SEWING MACHINES 4 SheetS-Sheet 2 Filed Dec. 4, 1931 gwvenlo o ill/red 11?. 14 3001.

auumq Ap 24, 1934. A. R. wooo FEED WHEEL STOP FOR BUTTONHOLE SEWING MACHINES 4 Sheets-Sheet 3 9116a Dec, 4, 1951 Jwomto o Alfred R. M061.

A ril 24, 1934. A. R. WOOD 1,955,994

FEED WHEEL STOP FOR BUTTONHOLE SEWING MACHINES Filed Dec. 4, 1931 4 Sheets-Sheet 4 Patented Apr. 24, 1934 UNITED STATES PTE i FFECE FEED-WHEEL STOP FOR BUTTONHOLE SEWING IVIACHINES Application December 4, 1931, Serial No. 578,966

6 Claims.

This invention relates to sewing machines of the buttonhole-sewing type having stitch-forming mechanism, a startand stop-motion device therefor, a work-clamp, and a feed-wheel making one complete rotation per buttonhole-producing cycle and connected to produce relative stitchpositioning movements between the stitch-forming mechanism and work-clamp to sew about a buttonhole. 1n machines of this type the feedwheel is customarily driven through a partial rotation during the actual sewing period. After the sewing is completed the feed-wheel is further and more rapidly driven through the remaining portion of its single rotation to restore it and the parts which it .actuates to starting position.

To prevent overthrow of the feed-wheel it has been proposed to equip it with a-friction-band but such a device puts a constant drag upon the feed-wheel and wastes power. Furthermore, it requires frequent adjustment to maintain the proper amount of friction to prevent overthrow without excessive drag.

The present improvement has for an object to provide a positive stop-device, as distinguished from a friction device, for preventing overthrow of the feed-wheel; further objects of the improvement being to provide for the automatic release of the feed-wheel from such stop, and for automatically renderin the stop-device again effective.

With the above and other objects in view, as will hereinafter appear, the invention comprises the devices, combinations, and arrangements of parts set forth and illustrated in the accompanying drawings of a preferred embodiment of the invention, from which the several features of the invention and the advantages attained thereby will be readily understood by those skilled in the art.

Fig. 1 is a right side elevation of the bed and standard and associated mechanism of a buttonhole sewing machine embodying the invention. Fig. 2 is a left side elevation of the same with the parts of the startand stop-motion device for the stitch-forming mechanism in starting or running position. Fig. 3 is a similar view with the parts of the startand stop-motion device in stopping position. Fig. 4 is a fragmentary perspective view of the feed-wheel of the machine and the latch-device for blocking the same against overthrow. Fig. 5 is a horizontal section through the machine bed, showing the feed-wheel in plan, and Fig. 6 is a top plan view of the work-clamping feet and upper thread-trimmer.

Except as hereinafter described, the machine is constructed substantially in accordance with the disclosure of the Allen Patents No. 1,346,102, of July 13, 1920, and No. 1,162,207, of Nov. 30, 1915. The frame of the machine includes the bed 1 from which rises the standard 2 of the usual bracket-arm structure supporting the reciprocating needle 3 which, together with the usual underthread mechanism mounted on the turret 4, constitutes the stitch-forming mechanism which is driven from the main sewing shaft 5. The period of operation of the stitch-forming mechanism is controlled by the usual start and stopmotion device, including the tilting startand stop-control lever 6 which in its vertical position, Figs. 1 and 3, arrests the motion of the main sewing shaft 5 and in its inclined or tilted position, Fig. 2, trips the usual clutch-device '7, associated with the continuously running belt-pulley 8, and effects the coupling of the main-shaft 5 to such pulley.

There is incorporated in the machine the usual buttonhole cutter-shaft 9 which makes one revolution prior to sewing and then comes to rest, and a second auxiliary shaft 10 which is stationary during the operation of the cutter-shaft 9 and sewing shaft 5 and makes one revolution after the sewing is completed, to perform certain desired operations after stitching, such as (1) the opening of the work-clamp, (2) the release of the tension device, and (3) the rapid drive of the feed-wheel to restore it to initial position. These shafts 9 and 10 are driven from a constantly rotating belt-pulley 11, Fig. 5, through suitably controlled one-revolution clutch-devices 12, 13, as fully explained in said Allen Patent No. 1,346,102.

It will sufiice here to explain that the second auxiliary shaft 10 is formed with a crank 14 which is connected by a pitman 15 to an arm 16 fulcrumed coaxially with the feed-wheel 1'7 and pivotally carrying a spring-pressed pawl 18 which acts upon the tooth 19 on the feed-wheel during the motion of the crank 14 from its dotted line position, Fig. 5, to full line position, rapidly turning the feed-wheel at one sweep from its position at the end of a sewing operation to initial position ready to begin a new cycle of operations.

The machine is equipped with the usual travelling work-clamp including thelower clampplates 20 and upper clamp- feet 21, 21"; the workclamp as a whole being moved longitudinally and laterally over the bed 1 to place the stitches about the buttonhole by the usual connections with the longitudinabfeed cam-groove 22 and lateral-feed cam-groove 23 in the feed-whee1 17. In the present instance the cam- grooves 22 and 23 are so shaped as to move the work-clamp in a path to effect the sewing of a round eyelet.

It is important in the operation of the machine that the feed-wheel, in its rapid movement to initial position, be not moved appreciably'past its initial or starting position as an overthrow of the feed-wheel past starting position interferes with the proper automatic action of the machine in the ensuing buttonhole-producing cycle.

To positively guard against the possibility of overthrow, without frictionally loading the feedwheel, I have provided a feed-wheel overthrowpreventing latch 24 which is fulcrumed at 25 on the bed 1 and has a lateral extension 26 overlapping the rim of the feed-wheel and adapted at times to drop into the groove 27 in the feedwheel and be struck by the feed-wheel-arresting abutment or shoulder 28 at the end of such groove. The spring 29 tends to yieldingly depress the latch 24 to feed-wheel-blocking position, Figs. 3 and 4.

The latch 24 is formed at its rearward end with a tooth 30 which is engaged at times by the shoulder 31 on the forward end of the link 32 pivotally connected at its rear end at 33 to the arm 34 pinned to the fulcrum-shaft 35 to which the tilting startand stop-motion lever 6 is fixedly connected.

It will be evident from a comparison of Figs. 2 and 3 that when the stop-motion lever 6 is tilted to running position, Fig. 2, the latch 24 is elevated above the feed-wheel 1'7 and the lateral extension 26 of the latch 24 is disengaged from or raised above the stop-shoulder 28, thus freeing the feed-wheel 17 for movement during the ensuing stitching operation. When the stop-motion lever 6 returns to its vertical position, Fig. 3, at the close of the sewing period of the buttonhole-producing cycle, the latch 24 is allowed to fall under the influence of its spring 29 to carry the lateral extension 26 into the leading end 27 of the groove 2'7 in the feed-wheel. At this same time or immediately following the return of the stop-motion lever to vertical position, the second auxiliary shaft 10 is tripped into action and, in the performance of its single rotation, the crank-and-link motion 14, 15, causes the pawl 18 to pick up the tooth 19 and quickly turn the feed-wheel 1'7 through the remaining angle of its one revolution or to full line position, Fig. 5, in which the shoulder 28 is very close to the lateral extension 26 of the latch-lever 24. Any overthrow movement of the feed-wheel 17 will be positively prevented by the abutment 28 striking the latch extension 26 and the feed-wheel will invariably stop in correct initial position.

The machine is preferably equipped with needle-thread cutting mechanism constructed substantially as follows: The upper clamp-foot 21 has pivotally mounted thereon at 36 an upperthread trimmer-device 3'7 constructed substantially in accordance with the disclosure of the Allen Patent No. 885,319, of April 21, 1908, but is distinguished from the disclosure of said patent by being arranged and operated so as to perform its closing or cutting-and-nipping move ment toward the side of the clamp-foot and away from the median line a-a of the Work-clamp, instead of at the end of the clamp-foot and in the direction of the median line, as heretofore. This arrangement requires a reversal of motion of the pivot-shaft 36 and its actuating crankarm 38 which is now connected by the link 39 to the reversing l ver 40 fulcrumed at 41 on the clamp-frame and having connected to its upper end the usual push-rod 42 and spring 43; said spring tending to hold the trimmer device 37 in closed position.

Provision is made for actuating the trimmer device 37 twice for each buttonhole-producing cycle, once after the initial stitches have been formed to release and retrim the beginning end of needle-thread, and again at the close of the stitching operation to cut the needle-thread and hold the end thereof leading from the needle. In my copending application Serial No. 391,589, filed September 10, 1929, I have shown and described a thread-trimmer mechanism embodied in a lock-stitch straight buttonhole sewing machine and having substantially this mode of operation. In the present instance the threadtrimmer and the means for actuating it twice per stitching cycle is embodied a buttonhole sewing machine of the rotary turret chain-stitch type disclosed in the Allen Patent No. 1,346,102, previously referred to.

By referring to Fig. 5 it will be seen that the feed-wheel 17 carries a cam 44 which, after the sewing has been well started, engages the arm 45 on the vertical rock-shaft 46 and rocks the latter in a direction to cause the bent arm 47 at the upper end of the rock-shaft 46 to engage and swing forwardly the arm 48 of the threadtrimmer opening bell- crank lever 48, 49; which engages the push-rod 42 and shoves it to the left, Fig. 1. When the heel 44 of the cam 44 passes the arm 45, the push-rod 42 is suddenly released and the spring 43 closes the trimmer and nipper device 3'? which retrims the beginning needle-thread ends.

When the sewing is completed and the second auxiliary shaft 10 is given its single rotation to restore the feed-wheel 17 to initial position, a cam 50 on the shaft 10 elevates the lnk 51 connected to the lever 52 whch carries a pin 53 engaging the forked rear end of the bell-crank lever-arm 49 and actuates the trimmer and nipper device 87 a second time.

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

1. A buttonhole sewing machine having, stitch forming mechanism, a startand stop-motion device therefor, a work-clamp, a feed-wheel, means for driving said feed-wheel through a partial rotation during the sewing operation, other means for further driving the feed-wheel after the sewing is completed to restore the feed-wheel to its starting position, a latch and abutment device for blocking overthrow movement of said feed wheel under momentum past starting position, and means for disengaging the elements of said device to free the feed-wheel for the next sewing operation.

2. A buttonhole sewing machine having, stitch-forming mechanism, a startand stopmotion device therefor, a work-clamp, a feedwheel, means for driving said feed-wheel through a partial rotation during the sewing operation, other means for further driving the feed-wheel after the sewing is completed to restore the feedwheel to its starting position, a latch and abutment device for blocking overthrow movement of said feed-wheel past starting position, and means under the control of said startand stop-motion device for unlatching said feed-wheel when the stitch-forming mechanism is started.

3. A buttonhole sewing machine having, stitch-forming mechanism, a startand stopmotion device therefor, a work-clamp, a feedwheel, means for driving said feed-wheel through a partial rotation during the sewing operation, other means for further driving the feed-wheel after the sewing is completed to restore the feedwheel to its starting position, a latch for blocking overthrow movement of said feed-wheel past starting position, and means controlled by said startand stop-motion device for moving said latch to feed-wheel-blocking position when the stitch-forming mechanism is stopped and for unlatching said feed-wheel when the stitch-forming mechanism is started.

4. A buttonhole sewing machine having, stitch-forming mechanism, a work-holder, a feed-wheel, a sewing shaft connected to drive said stitch-forming mechanism and feed-wheel during the sewing, said feed-wheel making only a partial rotation during the complete sewing of one buttonhole, a startand stop-motion device for controlling the period of operation of the sewing shaft, an auxiliary shaft stationary during the sewing, means for driving said auxiliary shaft through one revolution after the sewing is completed, a crank on said shaft and connections for driving said feed-wheel through the remainder of a complete rotation in a single sweep of said crank after the sewing is completed, a latch for blocking overthrow movement of said feed-wheel under the driving influence of said crank, and means for moving said latch to release the feed-wheel for the next sewing operation.

5. A buttonhole sewing machine having, in combination, a frame, a stitch-forming mechanism, a startand stop-motion device therefor, a work-clamp, a feed-wheel having an abutment, means for driving said feed-wheel through a partial rotation during the sewing operation, other means for further driving said feed-wheel through the remainder of one rotation after the sewing is completed to restore the feed-wheel to starting position, a pivoted latch mounted on the machine frame and cooperating with said abutment to prevent overthrow of said feed wheel past starting position, and means under the control of said startand stop-motion device for moving said latch to release the feed-wheel.

6. A buttonhole sewing machine having, in combination, a frame, stitch-forming mechanism, a startand stop-motion device therefor, a work-clamp, a feed-wheel having an abutment, means for driving said feed-wheel through a partial rotation during the sewing operation, other means for further driving said feed-wheel through the remainder of one rotation after the sewing is completed to restore the feed-wheel to starting position, a pivoted latch mounted on the machine frame and cooperating with said abutment to prevent overthrow of said feed-wheel past starting position, and means connected to said startand stop-motion device for controlling the feed-wheel-blocking and feed-wheelreleasing positions of said latch.

ALFRED R. WOOD.

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