US1807577A - Buttonhole sewing machine - Google Patents

Description

y 6, 1931- E. B. ALLEN 'BUTTONHOLE SEWING llACI-IINE Filed Nov. 29, 1927 8 Sheets-Sheet l INVENTOR zo ud a.

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WITNESZES ATTORN EY May 26, 1931. E. B. ALLEN BUTTONHOLE SEWING MACHINE Filed Nov. 29, 1927 8 Sheets-Sheet 2 U a W y 931. E.YB. ALLEN 1,807,577

BUTTONHOLE sswme mum 4 Filed Nov. 29. 1927 a Sheets-Sheet s f INVENTOR 4 m 5 46 WITNESS? 1 Q M ATTORNEY May 26, 1931. B. ALLEN 1,807,577

' I BUTTONHOLE SEWING MACHINE Filed NOV: 29. 1927 8 Sheets-Sheet 4.

wl mzssgg Y v 7? i ATTORNEY May 26, 1931. E. B. ALLEN 1,307,577

BUTTONHQLE SEWING IACHINE Filed Nov. 29, 1927 a Sheets-Sheet 5 7 May 26, 1931. 7

E. B. ALLEN BUTTONHOLE SEWING MACHINE 8 Sheets-Sheet 6 Filed Nov. 29, 1927 ATTORNEY y 1931? 7 E. B. ALLEN 1,807,577

' BUTTONHOLE SEWING MACHINE Filed Nov. 29, 1927 8 Sheets-Sheet '7 BLQ 1* l 150 l w A l 100- v a? INVENTOR m 7, mus? I BY k AI'IITORNEY y .1931, E. B. ALLEN 'BUTTONHOLE SEWING ncama Filed Nov. 29, 1927 8 Sheets-Sheet 8 INVENTOR- w flab ATTORNEY Patented May 26, 1931 I UNITED STATES EDWARD B. ALLEN, OF NEWI'OWN, CONNECTICUT, ASSIGNOR TO THE SINGER MANU- FACTUBJING COMPANY, OF ELIZABETH NEW JERSEY, A CORPORATION OF NEW JERSEY BUTTONHOLE SEWING MACHINE Application filed November 29, 1927.

This invention has for an object to provide improved control means for varying the sequence of operations of several independent groups of mechanism in an organized buttonhole sewing machine, and particularly to provide for the invariable automatic opening and unspreading of the work-clamp at the close of the button-hole producing cycle regardless of the particular sequence of operations of the previously acting mechanisms.

To secure the best quality of work, it is desirable that the buttonhole-slit be cut first and then overseamed, so that the stitches will cover the cut edges of the material, but with loosely woven or thin fabrics it is often necessary to change the order of the cutting and stitching operations, so that a sufficiently firm foundation may be had for reception of the oversea-m; the buttonhole slit being out after the overseam is completed.

In a modern automatic buttonhole sewing machine having, in addition to the buttonhole-cutting and stitch-forming mechanisms, clamp-closing mechanism, clampspreading mechanism, rapid-feed mechanism for effecting a rapid relative shift of the work-clamp and stitch-forming mechanisms into and out of sewing relation, clamp-opening mechanism and clamp-unspreading mechanism, the changing of the sequence or order of operation of the buttonhole-cutting and stitching mechanisms necessitates the provision of a system of control devices affecting the various other. mechanisms, in order that they may automatically follow one another in the desired order. It is with an improved system of control devices that the present invention is particularly concerned.

To the attainment of the ends in view the clamp opening and unspreading mechanism is provided with control means connected to the means for controlling the order of the buttonhole cutting and stitching operations, so that the work-clamp will be automatically opened and unspread regardless of whether the machine is set to cut the buttonhole before or after stitching.

1n the accompanying drawings, Fig. 1 is a right side elevation of a buttonhole sewing Serial No. 236,402.

machine embodying the invention. Fig. 2 is a left side elevation of the machine. Fig. 4-5 is a horizontal section through the bracketarm standard of the machine, showing the machine bed in plan. Fig. 4 is a bottom plan view of the machine. Fig. 5 is a rear-cnd elevation. Fig. 6 is a detached detail view of certain parts of the control mechanism shown in Fig. 5. Fig. 7 is a front-end elevation of the machine. Fig. 8 is a view of the selective control mechanism shown in F 1. Fig. 9 is a fragmentary transverse section through the machine bed showing details of the rapidfeed control mechanism. Fig. 10 is a sectional view on the line 99, Fig. 9. Fig. 11 is a section on the line 1111, Fig. 8. Fig. 12 is a detached plan view of certain parts of the control mechanism shown in Fig. 3. Fig. 13 is a section on the line 1313, Fig. 2. Fig. 14 is a section on the line 1414, Fig 2. Fig. 15 is a disassembled perspective View of the cam-member and its supporting shaft shown in Fig. 14. Fig. 16 is an elevation from the inside of the machine, looking at certain parts of the control mechanism in the reverse direction to that shown in Figs. 1 and 8. Fig. 17 is a detail view of certain parts shown in Fig. 16. Fig. 18 is a fragmentary vertical transverse section through the right side-wall of the machine bed on the line 1818, Fig. 8.

*ig. 19 is a section on the line 19-19, Fig. 0. Fig. 20 is a plan view of the parts shown in Figs. 18 and 19. Fig. 21 is a perspective view of one of the control levers shown in Figs. 18 and 19, and Fig. 22 is a View of the tension-release mechanism. 1

As the present invention'has to do wi a. novel control means for varying the sequence of operations of several independent groups of mechanism in an organized buttonhoic sewing machine, which groups of mechanism are old in the art, a brief description will first be given of the several old mechanisms followed by a description of the novel control means for varying their sequence of operation.

According tothe preferred embodiment of the invention illustrated, the machine is constructed with a frame including a hollow rectangular bed 1 from which rises the standsewing saaft.

ard 2 of the bracket-arm 3 terminating in the head 4.

The stitch-forming mechanism, its stopmotion device and the controlling means therefor are constructed substantially in accordance with the disclosure of the Allen Patent No. 15,324, reissued April 4, 1922, and the Allen et al., Patent No. 1,372,473, of March 22, 1921. Such mechanism comprises the usual needle 5 carried by the reciprocatory and rotary needle-bar 6 and the underthread mechanism 7 carried by the rotary turret 8. The needle and under-thread mechanism are given their stitch-forming movements by the usual connections with the main sewing shaft 9, as shown in said reissued patent, except for a slight change in the mechanism for reciprocating the central looper-bar 8'. In the present machine the looper-bar 8 is reciprocated by a link-connection 8 with a lever-arm 8 which is rigid with the lever-arm 8 fulcrnmed on the stud 8. The lever-arm 8 has a follower 8 entering a cam-groove 8 in the disk 0*- fiiied to the main-shaft 9. As the specific character of the actuating mechanism for the stitchforming devices has nothing to do with the present invention, further description thereof is deemed unnecessary. The period of action of the stitch-forming mechanism is controlled by means of the usual stop-motion device comprising the stop-motion lever 10 fixed to the pivot-shaft 11, journaled in bracket 12 fixed to the machine frame. The stop-motion lever 10 carries a downwardly springpressed locking tooth 13 which cooperates with the well-known stopping and clutch-controlling cam 14 on the main sewing shaft 9 on which is the constantly running belt-pulley 15. A tilting of the stopmotion lever 10 in a direction to compress the spring 16 withdraws the locking tooth 13 from the stop-notch. 14' in the cam 14 and establishes driving relation between the pulley and sewing shaft 9. The return of the stop-motion lever 10, under the influence of the spring 16, to the position shown in Fig. 1, effects disengagement of the sewing shaft 9 from the driving pulley 15. As the tooth 13, which is first elevated by the rise 14, Fig. 5, of the cam 14, drops into the stop-notch 14 in the latter, the shaft 9 is brought to a. positive step in a predetermined position with the needle 5 out of the work.

The operation of the stop-motion lever 10 is controlled by the pattern-cam 17, Fig. 2, on the cross-shaft 18, which cam acts upon the follower lever 19 connected by L118 link 29 to the arm 21 on the stop-motion lever pivot-shaft 11. When, in the turning movement of the cross-shaft 18, the cam ris 22 of the pattern-cam 17 engages the follower-nose 23 of the lever 19, it tilts the stop-motion lever 10 to running position and starts the lVhen the drop-off shoulder 24 of the cam 17 passes the nose 23, the spring 16 is free to shift the stop-motion lever ll) to the position shown in the drawings, to stop the sewing shaft.

The work-clamp comprises the lower clamp-plates 25 and upper clamp feet 26 which are mounted in the usual manner for movement over the machine bed to carry the work from buttonhole cutting or starting position to stitching position, thence in a path to place the stitches around the button hole, and lastly back to buttonhole cutting or starting position. These movements are derived from the usual feed-wheel 27 and pattern-wheel 17 through the usual connections, such as shown in said reissued patent. The feed-wheel 27 is connected by bevel-gearing 28 to the cross-shaft 18 which carries the pattern-wheel 17, so that both the feed-wheel and the pattern-wheel must run together. During the portion of the cycle when the stitch-forming mechanism is active, the feedwheel is driven in step-by-step fashion from the sewing shaft 9 through the usual pin and star-wheel drive 29, Fig. 4, and gearing train 30. During the portions of the cycle immediately preceding and following the sewing period, when the work-clamp is being carried to and away from sewing position, the feedwheel is driven at a continuous and more rapid speed from the rapid-feed shaft 31 which is driven continuously by the constantly running pulley 15 through the connecting train of gears 32.

The rapid feed-shaft 31 has fixed thereto a worm 33 which drives the gear 34- fixed to the live element of a clutch 35, the driven element 35 of which is lined to the cross-shaft 18. The clutch controlled by the sliding movement of the cone 36 on the shaft 18; driving relation being established between the shafts 31 and 18 when the cone 36 is moved away from the clutch 35 and interrupted when the cone is shifted toward the clutch. The shifting of the cone is effected by means of the arm 37 on the slidably mounted clutch controlling shaft 38, all of the foregoing mechanism being well known and disclosed, for example, in said reissued patent.

The rapid-feed-shaft 31 has formed therein a crank 39, Fig. 9, embraced by the forked arm 40 of a bell-crank-lever, the other arm 41 of which has pivotally connected thereto a push-bar 4-2 formed in its upper edge with a notch affording an abrupt shoulder -43 and an inclined shoulder 44. This bar 42, which is constantly reciprocated by the shaft 3]., is held in its idle position, Figs. 9 and 10, by a latch 45 pivoted at 46 on the machine frame. The spring 47 secured to the outer end of the bar 4-2 tends at all times to pull the bar 42 upwardly against the overhanging finger 45 of the latch. The latch 45 is formed with a slot 48 which receives a pin 49 on the arm 50 fixed to the rapid-feed starting rock-shaft 51. It will be understood that when the shaft 51 is rocked, the latch is swung to the right, Fig. 10, releasing the constantly reciprocating push-bar 42 which is swung up- V wardly by the spring 47, Fig. 9, until the notch between the shoulders 43, embraces the pin 52 on the pid-feed clutch-controlling shaft 88. Upon the next reciprocating impulse of the bar 42 to the right, Fig. 9, the abrupt shoulder 43 engages the pin 52 and pushes the bar 38 endwise to throw in the rapid-feed-clutch. The bar 38 is retained in clutching position by the upwardly springinfluenced latch-lever 58 which is fulcrumed at 54 independently of the bell-crank-lever 40, 41 and carries a shouldered piece which engages and retains the finger 56 carried by the bar 38. On the return endwise impulse of the bar 42 to the left, Fig. 9, the inclined shoulder 44 engages the pin 52 and depresses the bar 42 sufiiciently to be re-engaged by the overhanging finger 45' of the latch 45 and held in idle position. Thus, a rocking impulse of the shaft 51 throws into action the mechanism for rapidly driving the feedwieel. The throwing out of action of this mechanism is accomplished by trippingpoints 57, 58 on the inner face of the patternwheel 17. These tripping-points rock the lever 59, the forked end of which embraces the end of the latch lever 53and pulls the latter downwardly, thus causing the shoulder 55 to release the finger 56, whereupon the shaft 88' is returned to the rapid-feed declutching position by action of the spring 38, Fig. 4. The tripping-point 57 throws out the rapid-feed after the work-clamp has been moved from starting position to sewing position and the tripping-point 58 again throws out the rapid-feed after the work-clamp has been returned from stitching to starting p0sition near the close of the cycle of operations.

The work-clamping feet 26 are depressed to grip the work by clock-wise rocking movement of the connected shaft-sections 61, Fig. 1, such rocking movement being effected by the downward movement of the roller 62 carried by the forwardly extending arm 68 of the three-armed clamp-closing rock-lever, 63, 64, 65, fulcrumed at 66 on the machine frame; the roller 62 engaging the arm 66 fixed to one of the rock-shaft sections 61.

The three-armed clamp-closing lever 63, 64, is similar in function to and is controlled in the same manner as that disclosed in said reissued patent. When the machine is started, the clamp-closing lever is given a single complete to-and-fro movement by means of a cam-groove 67 in the inner face of the continuously driven belt-pulley 68. The rearwardly extending arm 64 of the clampclosing lever carries the endwise movable follower-pin 69 which is held in ejected position, out of engagement with the cam-groove 67, by the latch 70 pivoted at.71 to the standard 2. This latch is swung to the right, Fig. 1, to release the pin 69 by the action of the open tor in depressing the forward end of the starting lever 72, the rearward end of which engages a lever 73 which, in turn, is connected to the vertical rod 74 the upper end of which is connected to the bell-crank- lever 75, 76 also fulcrumed at 71. The arm 76 carries a pivoted catch 77 which engages the pin 78 on the latch 7 O and withdraws the latter from the notch 69, Fig. 3, in the pin 69 which is thereupon urged by the spring 78, Fig. 5, into the actuating cam-groove 67. After one co-andfro movement of the three-armed- lever 63, 64, 65, the pin 69 is ejected from the camgroove 67 and latched in ejected position.

The first movement of the three-armed lever is a counter-clockwise movement, Fig. 1, which closes the work-clamp. The work is spread by the action of a cam-bar 7 9 which is pivoted at 80 on the lever 80*, Fig. 16, the curved lower end of which carries a follower roll 80 in position to beactuated by a cam 80 on the vertical gear 28 early in the rapidfeed of the work-clamp from initial or button hole cutting position to sewing position. The bar 79 shifts the operating lever 81 of the usual clamp-spreading toggle-mechanism 82, described in said reissued patent, thus el'lecting the spreading of the worlcclamp.

The buttonhole cutting mechanism is sub stantially the same as that disclosed in said reissued patent and comprises the upper and lower cutter levers 83, 84 which are pivoted at 85 on the cutter-carrier fulcrum-block 86 1 which slides in ways formed longitudinally of the machine bed. The cutter-levers and carrier-block are operatively connected as usual with the cutter-shaft 87, the action of which is governed by a one-rotation clutchw device controlled by the cutter-clutch controlling lever 88 which is fulcrumed at 89 on the machine frame. The buttonhole cutter mechanism, cutter-clutch, and controlling lever 88 are well known and are disclosed in said reissued patent and in the Allen Patent No. 1,548,815 of August 11, 1925. When the lever 88 is shifted inwardly or away from the driven cutter-clutch disk 90, the coupling tooth 91 is released and slides outwardly under the influence of the spring 92 into en ga gement with one of the driving teeth 93, Fig. 5, of the driving clutch-member which is formed as a part of the continuously driven beitpulley 68. At the end of one revolution of the cutter-shaft 87, the tooth 91 is withdrawn from the driving tooth and the disk brought to a positive stop.

At the close of a cycle of operations the work clamp is automatically opened and unspread; the opening being accomplished by the bar 95 which is pivoted at 96 to the upright arm 97 of a bell-crank-lever 97, 98 fulcrumed at 99 on the machine frame. A rocking impulse of bell-crank-lever 97, 98 projects the front end of the rod into engagement with the upstanding arm fixed to the work-clamp rock-shaft section 61, tilting such arm forward and opening the workclamp. Previous to engagement of the bar 95 with the arm 100, however, the tripper 101 on the rod 95 engages the tail 102 of the latchlever 103 which locks the work-clamp in closed position by engagement with the tail 104 of the arm 100, as shown in dotted lines, Fig. 2. On the forward movement of the rod 95 the arm 105 fixed to such rod engages the lever 106 of the clamp-spreading toggle mechanism and shifts such lever to the position shown in Fig. 3, breaking the toggle and unspreading the work-clamp.

T he means for rotating the needle and looper mechanisms in sewing around theeyelet-end of a buttonhole and for reversely rotating such mechanisms after the sewing is completed, to return them to initial position are constructed substantially in accordance with the disclosure of said reissued patent and comprise the usual sector gear levers 107, 108, Fig. 2, and their respective link connections 109, 110, with arms 111, 112, on the vertical shaft 113; the arm 112 having a followerroll 114 which enters the cam-groove 115 in the feed-wheel 27.

All of the foregoing mechanisms are old in the art and disclosed in the cited prior patents. There now follows a description of the novel selective control mechanism for varying the sequence of automatic operation of such mechanisms to produce the two distinct types of buttonhole contemplated, (a), a cut-first buttonhole, the slit of which is out before the overseam is sewn, and (b), a cutafter buttonhole, the slit of which is out after the overseain is sewn.

Fnlcrumed at the right-hand side of the machine on the pivot screw 116 is the selec tive master control lever 117 to the lower end of which is secured by the screw 118, the leafspring arm 119 vertically slotted at 120 to embrace the screw 121 fixed to the arm 117. The head of the screw 121 is spaced out-wardly from the spring arm 119 and limits the outward movement of the latter. The arm 119 is vertically slotted at 122 to embrace the grooved outer end of ti e latch-pin 123 slidably mounted in the boss 124 fixed to the arm 117; the pin 123 being in position to enter one or the other of the holes 125, 126 in the guard 127 having a rigid arm 128, Fig. 1, whereby it is fixed by the screw 129 to the bed 1. The operator may grasp the handle of the lever 117, withdraw the latch-pin 123 by ma ipulation of the springarm119 and shift the lever 117 from one to the other of its operative positions. As shown in full lines in Fig. 8. the lever 117 is in cut-before position. It is shown in dotted lines in cutafter position.

There is connected to the master control lever 117, a link 1 :30 which is connected to a lever 131, Fig. 3, fulcrumed at 132 on the standard 2 and having its rearward end 133 bent at right angles to underhang the cutter-starting push-bar 134 which is pivoted at 135 to the arm (34 of the three-armed clamp-closing lever. This push-bar is the same in construction and function as that disclosed in said. Allen Patent No. 1,548,815. hen permitted to rest upon the rearwardly disposed angular extension 38 of the cutterclutch controlling lever 38, under the influence of the spring 136, as is the case when the lever 131 is in cut-first position, as shown in Fig. 16, the push-bar 134 is free for its tooth 137 to drop down behind the lever-arm 38 on the clamp-closing movement of the three-armed-levcr 63, G4, 65 and push the lever-arm 3S rearwardly on the return movement-of the three-armed lever, thus starting the buttonhole cutting mechanism immediately atter the work-clamps are closed. lVhen the master control lever is shifted to cut-after position the push-bar 134 is lifted to dotted line position, Fig. 8, by the action of the link 130 and lever 131, so that such bar 134 will reciprocate idly upon the actuation of the clamp-closing lever 63, 64, 65.

Mounted on the rapid-feed starting rockshaft 51 is an arm 138 on which is slidably mounted a follower-tooth 139 connected by the link 140 to the master control lever 117. lVhen the lever 117 is in cut-first position (full-lines, Fig. 8) the tooth 139 is within range of the tripping-point 141 on the driven cutter-clutch disk 90, whereby, as the cuttershaft 87 is completing its single revolution, the shaft 51 is rocked to start the rapid-feed mechanism. Vhen the master control lever is in cut-after position, the tooth 139 is withdrawn to dotted line position, Fig. 8, where it is out of range of the tooth 141.

The rapid feed-control rock-shaft 51 also has fixed thereto an arm 142 to which is pivoted at 143, Fig. 17, a latch-lever 144 having a tail piece 145 which is yieldingly held against the stop-pin 146 on the lever 142 by the spring 147, in which position (dotted lines, Fig. 17) the latch-lever 144 is within range of the actuating pin 148 on the downwardly extending arm 65 of the three-armed clamp-closing lever. In this position of the latch-lever 144, which is known as the outafter position, the pin 148 snaps past the latch-lever 144 on the first or clamp-closing movement of the three-armed clamp-closing lever and depresses the latch-lever 144 and rocks the lever 142 to start the rapid-feed mechanism on the return impulse of the clamp-closing lever. Vhen the tooth 139 is in full-line or cut-first position, an angle piece 149 Fig. 11, secured to said tooth 139, is in engagement with the pin 150 secured to the latch-lever 144 and is holding the latter in out-first position (full lines, Fig. 17) out of range of the pin 148. When the tooth 139 is shifted out of range of its actuator-tooth 141, the latch-lever 144 is permitted to oc cupy its dotted-line position, Fig. 17, within range of the pin 148.

It will thus be understood that two means are provided for starting the rapid-feed mechanism to rapidly shift the work-clamp from initial or buttonhole-cutting position to sewing position. One of these mechanisms is actuated by the buttonhole-cutting mechanism and the other by the clamp-closing mechanism, and when one of these mechanisms is active, the other is inactive, and vice-versa.

When the work-clamp reaches sewing position the rapid-feed mechanism is thrown out of action by the tripping point 57, Fig. 10, on the pattern wheel 17. At the same time the cam rise 22 on the pattern wheel tilts the stop-motion lever 10 to running position, thus starting the sewing mechanism. At the completion of the sewing operation the calm shoulder 24 passes the follower 23 and allows the spring 16 to restore the stop-motion lever 10 to stopping position. As the stopping tooth 13 is elevated by the cam rise 14" it operates through the lateral extension 151, Fig. 1, to tilt the lever 152 and draw downwardly the latch 153 the nose of which snaps under the rear end of the arm 154 fast to the rapid-feed starting rock-shaft 51. l/Vhen the tooth 13 drops into the stop-notch 14 in the stopping cam 14, the latch 153 is elevated and raises the arm 154,.thus starting the rapid-feed mechanism which shifts the work-clamp rapidly back to starting or buttonhole cutting position.

Pivotally mounted at the rearward end of the travelling work-clamp, on the screw 155 is a bar 156 which extends rearwardly alongside the standard 2 and passes loosely through a hole 157 in the bar 158. The bar 158 is connected by a screw 159 to the arm 160 of a bell-crank-lever fulcrumed at 161 on the standard 2. The other arm 162 of the bellcrank-lever extends over and rests upon the push bar 134, being held yieldingly thereupon by the spring 163 which is connected to the bar 158.

The bar 156 is formed with a longitudinally disposed rib 164 which enters a circumferential groove 165 in the hub of the clampopening and unspreading cam 166 which is slidably mounted on the cutter shaft 87; be-

where it may rotate idly without striking the follower lever 98. \Vhen the lever 117 is shifted to cut-after position the cam 166 is shifted to dotted line position, Fig. 14, where it may actuate the follower 98 and effect the opening and unspreading of the work-clamp.

The bar 156 also has secured to it a cam or tooth 17 0 which, when the master lever 117 occupies cut-first position, occupies full-.

line position, Fig. 13, where it wipes past the latch-lever 171 on the lever arm 98 on the rapid forward shift of the work-clamp from initial to sewing position. On the return rapid shift of the work-clamp, the cam 170 engages the latch-lever 171 and rocks the lever 98, 97, thus opening and unspreading the work-clamp. It will be observed that two means are provided for opening and unspreading the work-clamp and that when one of such means is active the other is idle, and vice-versa.

One means for starting the buttonhole cutting mechanism (prior to sewing) has already been described. Another means is provided for starting the buttonhole cutting mechanism (after sewing). Such means comprises a tooth 172 on the vertical gear 28. Just prior to the second stopping of the rapidfeed mechanism, the tooth 172 engages and 9 rocks the lever 173 which is, pivoted at 174 on the bracket 175. Pivoted at 176 on the lever 173 is a bell-crank- lever 177, 178, the upper end of the arm 178 of which is forked to form a aw 179 embracing the downward ly extending tail 180 of the cutter-clutch controlling lever 88.

The master control lever 117 is formed with a cam-slot 181 which is entered by a follower screw 182 passing through a vertical guide-slot 183, Fig. 18, in the fixed plate 184, and into the block 185 fixed to the slidepin 186 mounted in the fixed guide 187. The arm 177 of the bell-crank- lever 177, 178 is yieldingly held against the lower end of the pin 186 by the spring 188. When the lever 117 is in cut-first position, the pin 186 is depressed, and holds the jaw 17 9 of the lever 178 to the left, Fig. 20, of the tail 180 of the cutter-clutch controlling lever, so that the lever 173 will swing idly about the pivot pin 174 under the influence of the tooth 17 2. When the lever 117 is shifted to cut-after position, the pin'186 is elevated and the jaw 179 shifted to the right, Fig. 20, to embrace the tail piece 180 of thecutter-clutch controlling lever, whereby the cutting mechanism will be tripped into action at the close of the rapid-feed subsequent to sewing.

lVhen the starting rod 74 is pulled downwardly by the operator in pressing upon the starting button 72, it is detained in itsdownward position by the latch 189, Fig. 19, which has a notch 190 adapted to embrace the screw 191 fixed to the rod 74. Thisprevents reactuation of the clamp-closing mechanism during the operation of the subsequently timed mechanisms. When the lever 17 3 is tilted by the tooth 17 2, the arm 178 engages the hooked extremity 192 of the latch 189, Fig. 19, and swings the latch inwardly, releasing the rod 7a which rises to starting position under the influence of the spring 193.

The needle thread tension device 194 has the usual release pin 195 which is actuated by the lever 190 fulcrumcd at 197 on the bracket 197. The lower end of the lever 196 is shifted outwardly to release the tension by the camblock 198 fixed upon and adjustable lengthwise of the rod 199 which is secured at 200 to the travelling work-clamp. The rod 199 is guided in its endwise movements by the fixed bracket 201. The cam-block 198 is timed to release the tension early in the rapid feed of the workrlamp, subsequent to sewing. It is sometimes desirable to release the tension when the sewing reaches the end of a buttonhole, opposite the beginning end and for this purpose a second block 202 is secured to the rod 199. The block 202 has mounted thereon for vertical sliding movement into and out of range of the lower end of the lever 196, a cam-plate 203. \Vhen the cam-plate 203 is in full-line position, Fig. 2, it does not engage the tension release lever 196. Then moved upwardly to dot-ted line position, Fig. 2, it serves to release the tension when the sewing reaches the end of the buttonhole opposite the beginning end.

The machine is provided with mechanism, such as disclosed in the Allen Patent No. 1,504,300, of Aug. 12, 1924, for locking the clutch-device for the button hole cutting mechanism against accidental operation during a predetermined period of the operation 01" the machine. This mechanism comprises the cam 204 which actuates the follower arm 205 fast on the rock-shaft 200 to which is fixed the arm 207 connected by the link 208 to the bell-crank- lever 209, 210. The lever arm 210 cooperates with the push-bar 13 1 and cutter-clutch controlling arm 88 in the same manner disclosed in said Allen Patent No. 1,504,306.

The sequence of operations will he briefly traced for each of the two settings of the master control lever 117. \Vhen such lever is set in cut-first position, a push upon the starting button 72 trips the clamp-closing and spreading mechanism into operation. This mechanism operates through the push bar 134 to start the buttonhole cutting mechanism. The buttonhole cutting mechanism operates through the cam-tooth 141 and follower 139 to start the rapid-feed mechanism. The rapid-feed mechanism acts through the pattern-cam 17 to start the stitch forming and sewing feed mechanisms which are in turn stopped by the action of the cam shoulder 21 on the pattern-cam 17. The action of the tooth 13 on the stop-motion lever 10 starts the rapid-feed mechanism to return the workclamp to initial position, during which return the tooth 170 elevates the lever arm 171 to open and unspread the work-clamp.

When the master control lever is set in cut-after position, as before, a push upon the starting button 72, trips the clamp-closing and spreading mechanism into operation. This mechanism now operates through the pin 148 to depress the lever-arm 14-2 and start the rapidifeed mechanism. The rapid-feed mechanism, as before, starts the stitch-forming and sewing-feed mechanisms, which are stopped by the action of the cam-shoulder 24 on the pattern-cam 17. The action of the tooth 13 on the stop-motion lever 10, as before, starts the rapid-teed mechanism to return the work-clamp to initial or buttonhole cutting position. The rapid-teed mechanism now acts through the tooth 172 on the gear 28 to tilt the lever 17 3 and start the buttonhole cutting mechanism and the buttonhole cutting mechanism acts through the cam 166 to open and unspread the work-clamp.

Having thus set forth the nature of the invention what I claim herein is 1. In a buttonhole sewing machine, in combination, stitch-forming mechanism, buttonhole cutting mechanism, control means for varying the sequence of operations of said mechanisms, clamp closing mechanism, clamp-opening mechanism, and means connected with said control means for insuring the invariable opening of the work-clamp subsequent to the stitching and cutting operations.

2. In a buttonhole sewing machine, in combination, stitch-forming mechanism, buttonhole cutting mechanism, control means for varying the sequence of operations of said mechanisms, clamp-spreading mechanism, clamp-unspreading mechanism, and means connected with said control means for insuring the invariable unspreading of the workclamp subsequent to the stitching and cutting operations.

3. In .a buttonhole sewing machine, in combination, stitch-forming mechanism, buttonhole cutting mechanism, control means for varying the sequence of operations of said mechanisms, clan'ip-closing and spreading mechanism, clamp-opening and -unspreading mechanism, and means connected with said control means for insuring the invariable opening and unspreading oi the work-clamp subsequent to the stitching and cutting operations.

4. In a buttonhole sewing macnine, in combination. stitcluforming mechanism, buttonhole cutting mechanism. control means for varying the sequence of operations of said mechanisms, a work-clamp, a feed'wheel and connections for relatively moving the stitchtorming mechanism and work-clamp during the sewing and into and out of sewing relation, means including a continuously running drive-shaft and rapid-teed-clutch device for rapidly driving the teedwheel with a continuous motion during the relative shift of the stitch-forming mechanism and wor clamp into and out of sewing relation, and rapid-teed-clutch controlling means connected with said first mentioned control-means for insuring the invariable operation of the rapid-teed mechanism immediately prior to the operation of the stitch-forming mechanism, regardless of the time of operation of the buttonhole cutting mechanism.

5. In a buttonhole sewing machine, in combination, a work-clamp, clamp-closing means, buttonhole cutting mechanism including a cutter-shaft, clan'ip-opening mechanism, a device movably mounted on the cutter-shaft for actuating the clamp-opening mechanism, a second device movably mounted on the work-clamp for actuating the clamp-opening mechanism, and control means for so moving said devices, that when one is in position to actuate the clamp-opening mechanism the other is ineffective, and vice-versa.

6. In a buttonhole sewing machine, buttonhole cutting mechanism including a cutter-shaft, a cam keyed to rotate with and slide lengthwise of said shaft, a travelling work-clamp, a lever tulcrumed on said workclainp and having a sliding engagement with said cam, and clamp-opening mechanism arranged to be actuated by said cam in one po sition on the cutter-shaft, said cam being ineffective in another position on said shaft.

7. in a buttonhole sewing machine, abuttonhole cutting mechanism including a cutter-shaft, a cam keyed to rotate with and slide lengthwise of said shaft, a cylindrical hub on said cam having a peripheral groove, a travelling work-clamp, a cam-controlling lever pivoted on said work-clamp and having a rib engaging said groove, and clampopening meohanism arranged to be actuated by said cam. in one position of the latter on the cutter-shaft, said cam being ineffective in another position on said shaft.

8. In a buttonhole sewing machine, a workclainp, clamp-opening mechanism, a buttonhole cutter-shaft, and an actuating element on said shaft movable relatively to the latter into and out of position to actuate the clampopening mechanism.

9. In a buttonhole sewing machine, a traveliing work-clamp, clamp-opening mechanism, a buttonhole cutter-shaft, actuating elements on said cutter-shaft and work-clamp respectively movable into and out of position to actuate the clamp-opening mechanism, and means connected to said elements to move one out of operative position when the other is moved into operative position and viceversa.

10. In a buttonhole sewing machine, a buttonhole cutter shaft,a rapid-feed starting rock-shaft, a cam on the cutter-shaft, an arm fixed on said rock-shaft, a cam-follower slidably carried by said arm, and a control lever connected to slide said cam-f0llower on said arm into and out of range of said cam.

11. In a huttonhole sewing machine, a travelling work-clamp, clamp-opening mecha- HlSR'l mounted independently of the Wor:- clamp, an actuating element on said workclamp, and control means for moving said actuating element relatively to the workclamp into and out of a position operative to actuate the clamp-opening mechanism.

In testimony whereof, I have signed my name to this specification.

EDWARD B. ALLEN.

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