US2990795A

US2990795A - Automatic clamp opening mechanisms for sewing machines

Info

Publication number: US2990795A
Application number: US796538A
Authority: US
Inventors: Richard P Graham; William J Edwards; John D Garasimowicz
Original assignee: Singer Co
Current assignee: Singer Co
Priority date: 1959-03-02
Filing date: 1959-03-02
Publication date: 1961-07-04
Anticipated expiration: 1978-07-04

Description

July 4, 1961 R. P GRAHAM ETAL 2,990,795

AUTOMATIC CLAMP OPENING MECHANISMS FOR SEWING MACHINES Filed March 2, 1959 4 Sheets-Sheet 1 INVENTORS. RICHARD P. GRAHAM WILLIAM J. EDWARDS 9 6 JOHN D. GARASIMOWICZ WITNESS o Z TTORNE Y wF-i July 4, 1961 R. P. GRAHAM ETAL 2,

AUTOMATIC CLAMP OPENING MECHANISMS FOR SEWING MACHINES Filed March 2, 1959 4 Sheets-Sheet 2 Fig. 2.

INVENTORS. RICHARD P. GRAHAM WILLIAM .1. EDWARDS W1 TNESS JOHN D. GARASIMOWICZ I BY W W 9 ATTORIVEY July 4, 1961 R. P. GRAHAM ETAL 2,990,795

AUTOMATIC CLAMP OPENING MECHANISMS FOR SEWING MACHINES Filed March 2, 1959 4 Sheets-Sheet 3 INVENTORS. RICHARD P. GRAHAM WILLIAM J. EDWARDS W1 TNESS JOHN D. GARASIMOWICZ BY Z; 4Z4 ML /.-u

24,6? 7L ATTORNEY July 4, 1961 R. P. GRAHAM ETAL 2,990,795

AUTOMATIC CLAMP OPENING MECHANISMS FOR SEWING MACHINES Filed March 2, 1959 4 Sheets-Sheet 4 vm mm mm NQ mm 8 E R v R Ill INVENTORS. RICHARD P. GRAHAM WILLIAM J. EDWARDS B JOHN D. GARASIMOWICZ WITNESS W zid 'k ATTORNEY 'as .opcning of a wonkclamp,

United States Patent 6) 2,990,795 AUTOMATIC CLAMP PENING. MECHANISMS FOR SEWING MACHINES Richard P. Graham," Stratfrd; -William: J.

Nichols; and John Dr-Garasimowicz, assignors to-Th'e' Singe beth, N.J., a corporation of New Jersey Filed Mar-2, 1959,- Ser.': N0..796 ,538 7 Claims. (Cl. 112-239 particularly, to devicesror; automatically'etfecting; the operation of an appurtenance to I u vraising of a operation of a thread cutter, or. thedike.

presser. foot, y Itis an object of this invention .to provide animproved mechanism. driven independently of thestitchforming;

Edwards, Bridgeport, Conm, .Manufacturing Company, Eliza-- a sewing machinesuch.

10 This invention relates to seWingmachines and, more.

open thelclamp as-the sewing-machinestops.and torclose.

the clamp before. the sewing-machineis started.

With the above-and .other inafter appear, the inventiomcomprisesthedevices, combinations and arrangements of partshereinaftendescribed pfl ticularly pointed out in. the claims.

In' the .drawings which" illustrate aapreferredembodiment of the invention:

FIG. 1 representsa sideelevationalview of .a sewing machine having anautomatic clamp. opening mechanismi of this inventioniapplied thereto,

FIG.,2 represents a rear elevational... view of thesewing machine ofFIG. 1,

. FIG. 3"is'an enlarged:.vertical cross-sectional. view of a portion of the sewing machine taken. substantiallyalong line 33Jof FIG. 2, and

FIG. 4 is anenlargedhorizontal.cross-sectional viewof .a portion of the sewing, machineandfi the automatic clamp, opening mechanism taken substantially along; line. 4-14 of FIG. 1.

Referring to.the drawings, 11. chine casing whichcarries. an endwise reciprocating. needle 12 .anda rotary mainshaft. 13 by whichthemeedle and cooperating stitch .forming ,instrumentalities may be actuatedkin any known. manner. to form stitches The mainshaft13 is driven: and .the operation. of the sewingmachine is rendered cyclic by a stop motionmechanism illustrated inFIGS. l, 2..and.3.1 The mechanism. ofthis invention is adapted for use with any known form of stop. motion mechanism, thattillustrated in 'theedrawings. being of the-typeudisclosed in greater detail. in'the copending United States patentapplication oftKetterer etal., Serial No. 687,657, filed October.2, 1957, now Patent No. 2,906,222, granted September 29, 1959.

The following; brief description ofthe stop motion mechanism .will be suflicient. for an understanding,- ofthe present invention. Carried on'themainshaft 13am two. pulley halves 14' and 15, portion 14- fastonatheamainshaft andportion 15 freely journaled thereon and. supporting a..-belt' lfi by-which theportion 15 'is driven: constantly fromwae'motor. (not shown).- Astopmotion-frame 17' pivoted on a pin-18 carried in the sewing machinecasingv is fitted-with .an arm l9disp osed for engagement with the. free end ofthe-loose pulley whenthestopmotion frame: 17 istturned counterclockwise, as. viewed in; FIG. 3, to shift-the. loosenpulleyportion (15. toward- .the-fast pulley portion 14, thus bringing the belt 1 6 into driving engageindicates a. sewing .ma-

objects. in .yiew, as will here 2x4 ment with the fast frame 17also.carries'a stop arm 20 disposed for engagementawith. a notch 21 (FIG. 3) in the hub of thefast pulleywhen the stop motion frame is-turnedclockwise I 3, tolock the mainshaft. 13 in.a definite as viewed .in FIG. predetermined stoppedposition. V The stop motion frame 17 is spring biasedin a. clock? wise direction, as viewed in FIG. 3. The stop: motion.

frame may be turnedin a counterclockwisedirection, as

viewed in FIG. 3, to start the. sewing machine atthe will:

of:the operator by means. of a start lever 22 connected by a link.2'3 to onearm Qfalatch lever 214 fulcrumed; withinv thesewingmac-hine casing. The. other. arm of connected: by means of .a 1ink25 the latch lever 23 is tothe=stop motion frame 17.

The stop motion frame is restrained in runningposi tionby means of a latch. pawl 26 cooperating. with notches27, 28 on'the latchlever'24... The notch27 corresponds to a coasting position of the stop motion mechanism, i.e., anintermediate frame 29. vertical rock shaft 31 which,v as illustrated in FIG. 2, carries at-its. lower extremity a follower arm.32jpositione.d;

to be tripped by acam lug. 33, onthe mainpattern cam 34 of the. sewing ,machine-torelease the latch lever 24 andthus to stop the sewing machine.

. As best illustratedimFIG. l, fittedtwith awork-clampAt) in which the upper jaw member 41 is .slidable vertically in opposition to a leaf spring, 42so that. the .work clamp-jaws maybe. opened and closed. for removal and. replacement of work fabrics therebe-,

tween.

A pin- 43.extending fromthe upper jaw member 411 overlies a. block 44 carried .on a clamp, opening .bar.45

journaled vertically in the sewing machine casing. A co11ar. 46 fast onv theclampopening bar 45 is operativelyconnected :bymeans. of a link 47 and. a rock arm 48 to.a.rock shaft 49 journaledin the. sewing machine cas-' ingsubstantially parallel to. the mainshafti 13. The rock.

shaft. 49 has fast :thereon two

rockarms

50 and 51, turning of.either one. of .whichwill. result .in opening or closing-of thework clamp. jaws. The rock arm v50 is con-. nected-by a .link 52-,to amanual clamp opening lever 53 fulcrumed on the pivot pin 18.

The. rock. arm 51 on thetclamp opening rock shaft of acrank pin 63 secured on the shaft 62. The crank pin is connected'by means of'a link 64 to a pin 65' carried on the rock arm 51 of the clamp opening rock shaft. The link 64 is formed with a slot 66 which embraces the crankpin 63 so as to provide for lost motion between the link 64 and the automatic clamp'opening mechanism.

when the manual clamp opening lever 53 is used to open theclamp. The length of the crank pin 63 and the pin- 65 ispreferably made sufficient to accommodatexlimited endwise sliding movementof the shaft 62 without bind; ingv at. the link 64. Referring to FIG. 4, it willsbexaps' parent that; the distancebetween theaclamp opening rock; shaft-49 and the pin 65-;is greater: thanthe strokewofthe:

crank pin 63 on the shaft 62 so that turning movement Piafented 1 J u-ly 1 4, 1 96 1.

pulley portion. The stop; motion:

position of. the stop motion v =17 inwhich the. stop arm.20.is released from/the stop notch 21, but in which. the belt 1-6'is not yetin driv-- ing engagement withthe fast pulley. The notch 28. corresponds to thefullrunning position of the parts. A link connects =the.latch pawl 26 with a rock arm 30 on a.

the sewing.. machine is:

I I 3 of the shaft 62 will effect an oscillatory motion of the clamp opening rock shaft 49.

Journaled freely on the shaft 62 is a pulley 67 which is driven by a clip belt 68 from a sprocket 69 carried for rotation with the loose portion 15 of the stop motion pulley. The pulley 67 will, therefore, be driven continuously to provide a drive means constantly available to raise the work clamp. The hub of the pulley 67 is formed with a driving lug 70 which cooperates with a lug 71 formed on a collar 72 fast on the shaft 63 to provide a clutch means such that a driving connection is established whenever the shaft 62 is shifted endwise to the right, as viewed in FIGS. 1 and 4, to position the

lugs

70 and 71 in overlapping relation.

The shaft 62 is biased toward the right, as viewed in FIGS. 1 and 4, by means of a collar 73 fast on the shaft, which collar constrains a spring 74 under compression against a thrust bearing 75 which abuts the bracket 61.

The endwise position of the shaft 62 is controlled in opposition to the spring 74 by means of a control member taking the form of a lever arm 76 carried on a shaft 77 journaled in the machine casing. The lever arm 76 bears against a cam face 78 formed on the shaft collar 73. A lever arm 79 fast on the shaft 77 within the machine casing engages one extremity of the start lever 22. The position of the operator influenced start lever 22 thus controls the endwise position of the automatic clamp opening shaft 62. In the position illustrated in the drawings, in which the machine is locked in stopped position, the extremity of the starting lever 22 engaged by the lever arm 79 is lowered and the

lever arms

76, 79 urged by a light torsion spring 80 will be turned in a clockwise direction as viewed in FIG. 1 into an extreme position in which the shaft 62 is free to move endwise to bring the

lugs

70 and 71 into driving engagement.

The endwise position of the shaft 62 is also controlled by a stationary cam 81 carried on the bracket 61 and tracked by a follower finger 82 formed on a collar 83 fast on the shaft 62. The cam 81 is formed with a lobe 84 timed with respect to the follower finger to shift the

lugs

70 and 71 out of driving engagement when the shaft 62 and crank 63 occupy a position of rotation corresponding to the open position of the work clamp jaws.

The collar 83 is also formed with a lug 85 which cooperates with a latch lug 86 formed on the lever arm 76 to restrain the shaft 62 and the crank pin 63 in an angular position slightly beyond or over center from the extreme raised position of the work clamp jaw. The spring pressure acting to lower the work clamp jaw member 41, acting through the rock shaft 49 and the link 64, imparts a torque on the shaft 62 which is opposed by the engaged latch lugs 85 and 86.

Upon manual actuation of the starting leverv 22 to start the sewing machine, the lever arm 79 and with it the lever arm 76, will be shifted counterclockwise as viewed in FIG. 1. Initial movement of the lever arm 76 will effect a disengagement of the latch lugs 85 and 86 and the spring pressure tending to lower the upper clamp jaw.

member 41 will turn the shaft 62 approximately one half revolution. The cam face 78 cooperating with the lever arm 76 is formed with a slight protuberance 87 which istimed so as to be moved into engagement with the lever arm 76 upon release of the latch lugs 85 and 86 and to;

hold the driving lugs 70 and 71 out of driving engagement in this position of parts. I Y

Referring to FIG. 3, it will be apparent that an appreciable turning motion of starting lever 22is required before the pawl 26 can engage the first notch 27 in the stop motion latch lever 24. Preferably, release of the automatic clamp opener latch lugs 85 and86 is timed to occur before the pawl 26 engages the fir'stnotch 27 of the sewing machine starting mechanism. Thus, the work clamp will be closed before starting of the sewing machine is initiated. If after lowering the work clamp jaw and before continuing movement of the starting lever 22, the operator should desire to again open the clamp, this can be done automatically by simply releasing the starting lever 22. When the starting lever returns to the position illustrated in FIG. 1, the

lever arms

79, 76 will move clockwise to the position as viewed in FIG. 1, permitting the shaft 62 to move to the right for engagement of the driving lugs 70 and 71 and repositioning the latch lug 86 in the path of the lug on the collar 83 to restrain the Work clamp jaw member in opened position.

If after turning the starting lever 22 to close the work clamp jaws, the operator continues to turn the starting lever, the start and stop motion mechanism will be shifted into running position and maintained therein by engagement of the pawl 26 with the notch 28 in the latch lever 24.

Upon release of the pawl 26 by the stop cam 33 at the completion of a cycle of stitching operations, the starting lever 22 will be returned automatically to the position illustrated in the drawings and the lever arm 76 by way of the lever arm 79 will be turned topermit endwise shifting of the shaft 62 for engagement of the driving lugs 70, 71 to effect opening of the work clamp.

Thus, with the present invention, the work clamp may be opened and closed automatically in dependence upon the usual operation of the sewing machine starting lever. The mechanism is fast acting and reliable such that its use will not occasion time loss in the operation of the machine. The clamp opening mechanism of this invention is particularly adapted for installation as an attachment to existing machines in the field since its use ing said sewing machine intermittently, a work clamp carried on said sewing machine and having an open position and a closed position, means for biasing said work clamp into closed position, a clamp opening linkage operably connected'to said work clamp, a power operated clamp opening mechanism comprising, a rotary actuating device, means operably interconnecting said rotary actuating device to said clamp opening linkage, a rotating drive member, means for driving said rotary member continuously in one direction, clutch means carried on said rotary actuating device and on said rotating drive member, means supporting said rotary actuating device and said constantly rotating drive member for relative axial movement into and out of operative engagement of said clutch means, cam means for effecting axial movement of said rotary actuating device relatively to said constantly rotating drive member to disengage said clutch means in the position of said rotary actuating device corresponding to the open position of said work clamp, operator influenced latch means for restraining said rotary actuating device in a position corresponding to the open position of said work clamp, and operator influenced means for controlling the axial position of said rotary actuating device relatively to said constantly rotating drive member.

2. Mechanism for automatically opening a spring closed work clamp or the like of a sewing machine comprising a constantly rotating drive member, means for driving said rotating drive member independently of said lieing timed to operate in the open position of said clamp opening means, a shiftable control member, latch means associated with said control member, and means supporting said control member to shift said drive member and said rotary actuator into driving engagement and simultaneously to shift said latch means into effective position for restraining said clamp opening means in open position upon movement of said control member in one direction.

3. In combination, a sewing machine, means for driving said sewing machine intermittently, a work clamp carried on said sewing machine and having an open position and a closed position, means for biasing said work clamp into closed position, a clamp opening linkage operably connected to said work clamp, a power operated clamp opening mechanism comprising a rotary actuating device, means operably interconnecting said rotary actuating device to said clamp opening linkage, a drive member, means for rotating said drive member continuously in one direction during intermittent operation of said sewing machine, clutch means carried on said rotary actuating device and on said rotating drive member, means supporting said rotary actuating device and said rotary drive member for relative axial movement into and out of operative engagement of said clutch means, interengaging cam and follower means carried on said rotary actuating device and on the means supporting said rotary actuating device for effecting axial movement of said rotary actuating drive relatively to said rotating drive member to disengage said clutch means in the position of said rotary actuating device corresponding to the open position of said work clamp, an operator influenced control member having at least a portion thereof movable substantially parallel to the axes of said rotary actuating device and said rotary driving device, latch means on said portion of the operator influenced control member and on said rotary actuating device for restraining said rotary actuating device in a position corresponding to the open position of said work clamp, and means on said portion of said operator influenced control member for controlling the axial position of said rotary actuating device relatively to said rotary driving member.

4. In combination, a sewing machine, a work clamp carried on said sewing machine and having an open position and a closed position, means for biasing said work clamp into closed position, a clamp opening linkage operably connected to said work clamp, a power operated clamp opening mechanism comprising a shaft, means for supporting said shaft for turning and axial shifting movements, a rotary actuator carried on said shaft, means permanently connecting said rotary actuator to said clamp opening linkage, a constantly rotating drive member, clutch means carried on said shaft and on said rotary drive member engageable upon axial movement of said shaft in one direction, cam means for shifting said shaft axially in the opposite direction to disengage said clutch means in the position of said rotary actuator corresponding to the open position of said work clamp, operator influenced latch means for restraining said rotary actuator in a position corresponding to the open position of said work clamp, and operator influenced means for controlling the axial position of said shaft.

5. In combination, a sewing machine, a work clamp carried on said sewing machine and having an open position and a closed position, means for biasing said work clamp into closed position, a clamp opening linkage operably connected to said work clamp, a power operated clamp opening mechanism comprising a shaft, means for supporting said shaft for turning and axial shifting movements, a rotary actuator carried on said shaft, means permanently interconnecting said rotary actuator to said clamp opening linkage, a constantly rotating drive member, clutch means carried on said shaft and on said rotary 6 drive member engageable upon axial movement of said shaft in one direction, interengaging cam and follower means carried on said shaft and on said means for sup porting said shaft for shifting said shaft axially to disengage said clutch means in the position of said rotary actuator corresponding to open position of said work clamp, an operator influenced control member, means for supporting said operator influenced control member for movement relatively to said shaft, interengaging latch means carried on said shaft and on said operator infiuenced control member for restraining said rotary actuator in a position corresponding to the open position of said work clamp, and interengaging means on said shaft and on said operator influenced control member for controlling the axial position of said shaft.

6. In combination, a sewing machine, a Work clamp carried on said sewing machine and having an open position and a closed position, means for biasing said work clamp into closed position, a clamp opening linkage operably connected to said work clamp, a power operated clamp opening mechanism comprising, a shaft, means for supporting said shaft for turning and axial shifting movements, a rotary actuator carried on said shaft, means permanently interconnecting said rotating actuator to said clamp opening linkage, a constantly rotating drive member journalled loosely on said shaft, clutch means carried on said rotary driving member and on said shaft for operative engagement upon axial movement of said shaft in one direction, spring means for biasing said shaft axially in the direction to engage said clutch means, an operator influenced control member disposed in operative engagement with said shaft, means supporting said operator influenced control member for movement axially of said shaft in opposition to said spring means, interengaging cam and follower means carried on said shaft and on said means for supporting said shaft for shifting said shaft axially in opposition to said spring means to disengage said clutch means, means for timing said cam and follower means to disengage said clutch means in the position of said rotary actuator immediately beyond that corresponding to the maximum opened position of said work clamp, and interengaging latch means carried on said shaft and on said operator influenced control member for restraining said rotary actuator in the position occupied upon disengagement of the clutch means by said cam and follower means.

7. In combination, a sewing machine, means for driving said sewing machine intermittently, a work clamp carried on said sewing machine and having an open position and a closed position, mechanism for opening and closing said work clamp comprising a shaft, means for supporting said shaft in turning and axial shifting movements, rotary actuating means fast on said shaft and adapted to be operably connected to open and close a sewing machine work clamp or the like, a drive member journaled freely on said shaft, means for imparting continuous rotary motion to said drive member, interengaging clutch means carried on said shaft and on said drive member engageable and disengageable upon axial shifting movement of said shaft, operator influenced means for at will shifting said shaft axially to engage said clutch means, and cam means automatically effective upon a fraction of a revolution of said shaft for shifting said shaft axially to disengage said clutch means.

References Cited in the file of this patent UNITED STATES PATENTS 117,708 West Aug. 1, 1871 709,354 ODonnell Sept. 16, 1902 1,273,348 Fifield July 23, 1918 2,532,266 Andres Nov. 28, 1950 2,540,987 McOann Feb. 6, 1951 2,730,058 McCann Jan. 10, 1956