US1379894A - Work-clamping mechanism for sewing-machines - Google Patents

Description

E. B. ALL EN. WORK CLAMPING MECHANISM FOR SEWINI MACHINES. APPLICATION FILED OCT- 20, I9I5- RENEWED SEPT. I7, 1918- 1,379,894. Patented May 31,1921;

2 SHEETS-SHEET WINES-86$: 0%. 91M

P E. B. ALLEN. WORK CLAMPING MECHANISM FOR SEWING MACHINES;

APPLICATION FILED OCT, 20, 1915- REN EWED SEPT. 17,1918. 1,379,894.

Patented May 31, 1921.

2 SHEETS-SHEET 2.

INVENTOR EDWARD IB. ALLEN; OF BRIDGEPOBT, CONNECTICUT, ASSIGNOR TO THE SINGER MANN- FACTURING COMPANY, A CORPORATION OF NEW JERSEY.

WORK-CLAMPING MECHANISM non SEWING-MACHINES.

T 0 all w liom it may concern:

Be it known that I, EDWARD B; ALLEN, a

citizen of the United States, residing at' Bridgeport, in the county of F airfield and State of Connecticut, have invented certain new and useful Improvements in W'ork- Clamping Mechanisms for Sewing-Machines, of which the following is a spec1fication, reference being had therein to the accompanying drawings.

The present invention has for its ob ects to simplify and effect the positive control of the clamp-closing means and to secure therefor a more advantageous timing relative to the operative movements of the cuttlng device.

In the preferred form of the present 1mprovement, the cutting device comprises a traveling fulcrum-pin upon which are mounted the cutter-carrying rocklevers actuated by separate cams upon the transverse cutter-shaft, the fulcrum-pin being mounted upon a slide-block deriving operative movements from an adjustable connection with another cam upon the cutter-shaft. The clamp-operating cam-shaft upon one of the laterally separable sections of the workclamp has the usual lateral tappet-arm which is engaged by the forward extremity of the clamp-closing rock-lever mounted upon a fixed fulcrum and having intermediate its fulcrum and its outer end an arched cam-slot which is entered by a stud carried by the lower cutter-lever.

In the travel of the cutting device between retracted and cutting positions the substantially rectilinear advance of the stud with the lower cutter-lever through the initial inclined limb of the cam-slot causes the descent of the clamp-closing rock-lever for engagement with the tappet-arm of the clamp-operating rock-shaft just after the forward end of the lower cutting element moves beneath the adjacent end of the workclamping foot. As the cutting device continues its advance to cut ting position, the movement of the stud in. the forward and reversely inclined portion of the arched cam-slot causes the rise of the clamp-closing rock-lever to afford ample clearance between its operative end and the tap'p'et-arm, in order that the final rocking of the lower cutter-carrying lever Specification of Letters Patent. Patented May31, 1921, Application filed October 20, 1915, Serial No. 56,849. Renewed September 17, 1918.

Serial No. 254,512.

in the cutting action may not carry the While the traveling cutting device'is preferably employed in the actuation of the clamp-closing rock-lever in a machine employing this type of device for producing the buttonhole slit, ciprocating member performing an operative movement preparatory to the buttonhole cutting operation maybe employed in producing the described result. It is also evident that the mechanism as above deit is evident that any rescribed may be modified in other particulars within the scope of the present invention.

In the drawings, Figure 1 is a side elevation of the lower portion of a buttonhole sewing machine embodying the present improvement, and Fig. 2is a plan of the same. Figs. 3 and f are views similar to Fig. 1,

with the omission of certain parts below the top of the bed of the machine, representing the cutting device and the clamp-closing means in different positions.

As represented in the drawings the frame of the machine includes the hollow rectanguiarbase -1 having a suitably apertured top forming the bed-plate 2. The base is shown provided with the removable forward section 3 for access to the looper mechanism cooperating with a reciprocating and laterally jogging thread-carrying needle 4 sustained above the bed-plate. The stitch-forming mechanism, as thus constituted, is or may be constructed and operated as represented in my United States Patent No. 1,030,046, of June 18, 1912, but its specific character is not material to the present improvement.

Suitably journaled in the base is the longitudinally extending main-shaft 5 formed with qua-rtering cranks 6 embraced by the lower ends of pitman-rods '7 by'mea-ns of which it is connected with the upper needleactuating shaft. The main-shaft 5 carries the cam-cylinder 8 having the peripheral cam-groove 9 entered by a roller-stud upon an arm of the rocker 1O fulcrumed beneath the bed-plate.

The rocker 10 is connected by means of the pitman 11 with the clutch-lever 12 which actuates the clutch-dogs l3 embracing a depending flange of the feed-wheel 14. The

feed-wheel is shown provided in its upper face with the usualfeeding cam-groove 1 and side-shift cam-groove 16. The camgroove 15 is entered by the roller-stud 17 depending from the swinging arm 18 fulcrumed at 19 and provided with the longitudinally adjustable stud 20 entering a transverse slot 21 in the Work-clamp slide-plate 22. The cam groove 16 is entered by a stud depending from the rock-lever 23 havinga sliding and pivotal connection with the usual cross slide-plate mounted for endwise movement upon the slide-plate 22 in a manner well known.

The slide-plate 22 sustains the edgewise and reciprocally movable clamp- plates 24 and 25 affording the lower clamping members of the work-holder. ,Each of these clamp-plates has adjustably secured thereon a bearing bracket 26 sustaining near its foot the fulcrum-pin 27 of one of the upper forwardly extending clamp-arms 28 carrying the pivoted foot 29 constituting one of the upper clamping members. Journaled in the bearing bracket 26 above the adjacent portion of the clamp-arm 28 is the transverse clamp-operating rock-shaft 30 provided upon one side with the cam projection 31 adapted for engagement with the clamp-arm for pressing the same downward to close the clamp in opposition to the lifting spring 32.

The rock-shafts 30 are in the present construction made separate to enable the separable sections of the clamp to be shifted relatively and they are coupled together when in operative position by means of a crank-arm 33 fixed upon the one and provided with a lateral pin 34 entering a fork 35 in a similar crank-arm 36 fixed upon the other of said rock-shafts. The rock-shaft 30 at the right, as seen from the front end of the machine, is provided with a laterally extending bent tappet-arm 37 and with an upwardly extending tappet-arm 38 by means of which the shaft may be rocked in opposite directions for closing and opening the clamp. The said rock-shaft is also provided with the finger-lever 39 by means of which the clamp may be manually operated the movements of one rock-shaft being communicated to the other by the connection before described.

Suitably journaled in the frame slightly above the bed-plate 2 is the transverse cutter-shaft 40 provided upon one end with the loose grooved belt-wheel 41 derivingcon- 5 .This clutch tinuous rotary motion from a belt leading from the source of power independently of the main-shaft 5. Between the hub 42 of the belt-wheel 41 and the disk 43 fixed upon the shaft 40 is a clutch device controlled by means of the flange 44 of the controlling lever 45 fulcrumed at 46 and pressed normally into clutch-disengaging position by means of the spring 47 interposed between the flange 44 and the boss 48 rising from the bed-plate 2. device operates to control the connection of the cutter-shaft with its driving means in such manner that the shaft performs a single rotation only preparatory to each buttonhole stitching operation.

The cutter mechanism represented in the drawings is substantially that of my Patent No. 1,048,786. It comprises a traveling fulcrum-block having spaced parallel flanges 49 between which are pivotally mounted by means of the fulcrum-pin 50 the upper and lower cutter-carrying levers 51 and 52. The upper lever 51 carries the cutting knife 53 and the lower lever carries the cooperating block 54. The fulcrum-carrying slide-block is fitted within a suitable slideway of the bed-plate.

The rearward ends of the cutter-levers are drawn together by means of a spring 55 which maintains the fiat adjacent edges of I the cutter-levers permanently in contact or operative relation with their respective actuating cams 56 and 57 fixed upon the cutter-shaft 40. The cutter-shaft has also secured thereon the cam-disk 58 formed in one face with the cam-groove 59 entered by the lateral stud 60 of the link-bar 61 having at its rearward end a yoke 62 embracing the cutter-shaft and its forward end apertured to receive the stud-bolt 63 projecting laterally from the rearward extension of one of the fulcrum-sustaining flanges 49, whereby the fulcrum-block and the cutter-levers are given traveling movements toward and from stitching position preparatory and subsequent to each buttonhole cutting operation. The cutting device thus performs but a single reciprocatory traveling movement for each. feeding cycle measured by a rotation of the feed-wheel.

Secured upon the bed-plate 2 is a bearing bracket 65 carrying the fulcrum-stud (36 upon which is pivotally mounted the clampclosing rock-lever 67 with its laterally offset and depending rounded forward end 68 disposed normally above the tappet-arm 37 in the initial position of the work-clamp.

Between its laterally offset forward portion and its fulcrum point the clamp-closing rock-lever is formed with an arched camslot comprising the substantially horizontal portion 69., and adjacent upwardly and forwardly inclined portion 70 and a forwardly and downwardly inclined portion 71. This cam-slot is entered by the lateral stud 72 projecting from the front face of the lower cutter-lever 52, and preferably provided with an anti-friction roller 73 upon the portion embraced by the cam-slot.

Then the cutting device is in its normally retracted position, the stud 72 occupies a position within the portion 69 of'the camslot, as represented in Fig. l. In-the initial travel of the cutting device to cutting position under the action ofthe cam 58 and link-bar 61, the stud '72 traverses the camslot portion 70 and imparts a full operative downward stroke to the rock-lever 67 68, and by its'engagement with the tappet-arm 37 depresses the clamping feet 29 upon the work while the cutting elements continue their movement to cutting position in register with the clamping feet.

In the continued advance of the cutting device, the stud 72 traverses the .camslot portion 71 and thereby lifts the rock-lever 67 68 clear of the tappet-arm 37, so that in the final closing movement of the cutting elements the descent of the stud 72 in the rocking movement of the lower cutter-lever 52 will not impart to the clamp-closing rock-lever a dip sufficient to cause a reengagement of the rock-lever with the tappet 37 with such force as to turn the rock-shaft 3O appreciably beyond its normal clampclosing position or to injure the parts.

In the return of the cutting device to initial retracted position, the rock-lever 67 68 obviously receives movements correspondwith those described but in the reverse order, and without affecting the position of the work-clamp which remains closed by reason of the positioning of the cam projection 31 beyond the center of the rockshaft 30.

The horizontal cam-slot portion 69 is designed to afford clearance for the stud 72 in the adjustment of the connection 63 between the link-bar 61 and the fulcrum-carrying block in order to properly locate the cutting position relatively to the work-clamp for different cutting elements which the cutterlevers are designed to accommodate interchangeably. The clamp-closing rock-lever and its cam-slot are preferably so shaped and positioned with relation to the stu'd72 that the closing movement of the clamp is not commenced until the lower cutting element or lCDlfG-blOCk has advanced sufliciently to lie beneath the adjacent ends of the clamping feet so as to avoid the collision of their adjacent extremities and consequent injury of the parts.

As described more fully in my said application, the top of the bed-plate is longitudinally channeled to receive the slide-bar 74 from which rises the post 75 carrying the adjustably mounted clampopening tripping pin 76 adapted for engagement with the tappct-arm 38 of the clamp-operating rockshaft 30. The slide-bar 74 is connected by a link '77 with the laterally extending arm 7 8 fixed. upon a rocking pin 79 extending through the bed-plate and carrying upon its lower end the arm 80 normally lying in'the path of movement of the cam projection 81 upon the-feed cam-wheel 14, the arm '80 rest-' ing normally upon the periphery of the latter by the action of the spring 82 connecting and the clamp closing rock-lever; while the said rock-lever is positively controlled and is not dependent upon a spring whose disconnection or breakage would permit the rock lever to assume a position during the travel of the work-clamp which ,would cause a collision likely to disarrange or injure the parts involved. 7

Although in the embodiment of the present improvement represented in the accoanpanying drawings the connection between the reciprocatory cutter-carrying member and the clamp-closingrock-lever is in the form'of a cam-track and a follower-stud engaging the same, it is obvious that the present invention includes within its scope any other suitable means for converting the substantially rectilinear reciprocatory movement of the one into a tilting o-r vibratory movement of the other. I

Having thus set forth the nature of the invention, what I claim herein is 1. In a buttonhole sewing machine, the combination with stitch-forming mechanism, a work-clamp, and means for producing between the same relative feeding.

movements, of clamp closing means includmg a rock-lever mounted independently of and adapted for engagement with an element of the work-clamp, an actuating membervperforining a complete bodily reciprocation relatively to and lengthwise of said rock-lever once only for each feeding cycle, and an operative connection between said actuating member and the rock-lever for imparting to the latter its operative movements. 7

2. In a buttonhole sewing machine, the combination with stitch-forming mechanism and a work-clamp, of clamp-closing means including a rock-lever, a fixed fulcrum therefor, a reciprocatory actuating member, and an operative connection between said rock-lever and actuating member comprising a cam element upon the one and a follower thereior upon the other.

3. In a buttonhole sewing machine, the combination with stitch-forming mechanism and a work-clamp, of clamp-closing means including a rock-lever having a camtrack, fixedl ulcrum for said rock-lever and a reciprocatory actuating member, and a stud carried thereby in operative engagement with said cam-track of the rock-lever.

l. in a buttonhole sewing machine, the combination with stitch-forming mechanism and a worloclamp, of clamp-closing means including a rocking and reciprocating actuating member, a stud carried thereby, and a rock-lever having a cam element adapted for operative engagement by said stud and shaped to eftect a to-and-fro rocking movement of said lever in the travel of said member preparatory to its rocking movement.

5. In a buttonhole sewing machine, the

combination with stitch-forming mechanisin, a work-clamp, and a bodily traveling buttonhole cutting device having cutting elements movable into and out of register with the work-holder, of clamp-closing means comprising a rock-lever mounted independently of the work-clamp and relative to which rock-lever said cutting device performs its traveling movements, and. an operative connection between the cutting device and said. rock-lever including a cam element upon the one and a follower there for upon the other.

6. In a buttonhole sewing machine, the combination with stitch-forming mechanism, a work-clamp, and a buttonhole cut ting device comprising two carriers, cooperating cutting elements mounted respectively upon said carriers, a pivotal connection between said carriers, and means for imparting to said carriers bodily traveling movements toward and from the workclamp and relative rocking movements upon said pivotal connection, of clamp-closing means comprising a rock-lever mounted independently of said wont-clamp and relative to which rock-lever said carriers perform their traveling movements, and an operative connection between the rock-lever and one of said carriers including a cam element upon the one and a follower upon the other.

7. In a buttonhole sewing machine, the combination with stitch-forming mechanism, a work-clamp, and a buttonhole cutting device comprising two carriers, cooperating cutting elements mounted respectively upon said carriers, a pivotal connection between said carriers, and means for imparting to said carriers traveling movements toward and from the work-clamp and relative rocking movements upon said pivevasea otal connection, of clamp-closing means comprising a rock-lever formed with a camtraclr inclined to the direction of traveling movement of the cutting device, and a stud sustained by one of said carriers and engagingsaid cam-track to produce a rocking movement of said lever.

8. ln buttonhole'sewing machine, the combination with stitch-forming mechanism, a work-clamp, and a buttonhole cu: ting device comprising upper and lower cutting levers, cooperating cutting elements mounted respectively upon said levers, a "fulcrum-stud upon which said levers are mounted, means for imparting to said fulcrum-stud traveling movements toward and from the work-clamp, and means for imparting to said levers reciprocal rocking movements upon said fulcrum-stud, or a worn-holder comprising an upper clamping member and a controlling rock-shaft therefor provided with a tappet-arm, a rocklevermounted independently of the workclamp and adapted for engagement with said tappet-arm and an operative connection between the lower cutter-lever and the rock-lever comprising a cam element upon the one and a follower therefor upon the other from which the rock-lever derives operative clamp-closing movements.

9. in a buttonhole sewing machine, the combination, with stitch-forming mechanism and a work-clamp, of elamp-closing means including a rock-lever, an actuating member and means for imparting to it reciprocatory movements substantially length wise of said roclolever, and an operative connection between and sustained by said rock-lever and actuating member for closing the work-clamp into gripping relation with the work during a bodily traveling movement of said actuating member.

10. In a buttonhole sewing machine, a frame, a work-clamp and traveling buttonhole cutter-levers movable relatively to said frame, a clamp-closing lever :r'ulcrumed on said frame, and means carried by one of said cutter-levers and acting upon said clamp-closing lever to close the work-clamp into gripping relation with the work during the travel of said cutter-levers to cutting position.

11. In a buttonhole sewing machine, a frame, a work-clamp and traveling buttonhole cutter-levers movable relatively to said frame, a clamp-closing lever fulcrumed at one end to said frame and having its other end disposed in operative relation with an element 0:6 the worloclamp, and an operative connection between one of said cutterlevers and a point on said clamp-closing lever intermediate the ends of the latter.

12. lln a buttonhole sewing machine, in combination, a work-clamp, buttonhole cutting mechanism including traveling cutterpoint, buttonhole cutting mechanism in-' cluding a cutter carrying element and an operative connection for transmitting power from said element to said clamp-closing lever.

14. In a buttonhole sewing machine, a

stationary frame, a traveling work-clamp sustained by said frame, a clamp-closing lever pivoted to a stationary part of the frame, buttonhole-cutting mechanism including a traveling cutter, and an operative connection for transmitting power from said traveling cutter to said clamp-closing lever.

15. In a buttonhole sewing machine, a stationary frame, a traveling work-clamp sustained thereby, a buttonhole cutter, a cutter-operating shaft, a clamp-closing lever fulcrumed on said frame, and a cam operated connection distinct from said cutter-operating shaft between said buttonhole cutter and clamp-closing lever.

16. In a buttonhole sewing machine, a work-clamp, a clamp-closing lever, an actuating device mounted for reciprocation in a direction lengthwise of said lever, and an operative connection between said lever and actuating device comprising a cam and c0- operative member, said cam extending mainly in a. direction lengthwise of said lever but having a side throw sufiicient to rock the clamp-closing lever and close the Clamp.

17. In a buttonhole sewing machine, a I

stationary frame, a traveling work-clamp sustained by said frame, buttonhole cutting mechanism including a cutting lever, a clamp-closing lever fulcrumed at one end to said frame, and a connection. for transmitting power from said cutter-lever to said clamp-closing lever.

In testimony whereof, I have signed my name to this specification,in the presence of two subscribing witnesses.

EDWARD B. ALLEN. Witnesses:

STANLEY N. SMITH, HENRY J. MILLER.

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