US2079493A - Attachment for sewing machines - Google Patents

Description

May 4, T937. s, MCREWDSON Y 2,079,493

ATTACHMENT FOR SEWING MACHINES Filed April 15, 1955 2 sheets-sheet 1 @-1- L III May 4 E37 Aes. M. cREwDsoN 2,079,493

ATTACHMENT FOR 4SEWING MACHINES Filed April i5, 1955 2 sheets-sheet 2 Patented May 4, 1937 UNITED STATES PATENT OFFICE Sarah M. Crewdson, Chicago, Ill., assignor of one-third to Robert H. Goodhart, Chicago,

Ill.

Application April 15,

Claims.

The invention relates to an attachment for sewing machines and has for its object to provide for an attachment that will trim a seam by cutting the material to form either a straight 5 edge or an irregular edge at a predetermined distance from the seam.

The invention is particularly concerned with a pinking and cutting attachment for location on the work supporting surface of the sewing machine to the rear of the needle and which will have connection with the reciprocating needle bar for driving the cutting or pinking element. The speed of rotation of said element is thus dependent on that of the needle bar which, however, reciprocates at a constant speed although the feeding mechanism. of the machine may vary. In fact sewing machines as now manufactured are provided with means for varying the speed of the feed mechanism and the ma- 0 chine can be adjusted to sew a certain number of stitches to the inch, which may range from a low of six to a high of thirty, with deiinite increments of increase between these limits. This variation in the speed of operation of the feed produces changes in the rate of travel of the material through the machine and in order that the cutting or pinking element may have a rate of travel in synchronism therewith, it is necessary to introduce a variable clutch in the drive operatively connecting the attachment to the reciprocating needle bar.

The invention has for its primary object the provision of means for driving the rotary shaft of a cutting or pinking attachment from the reciprocating needle bar of the sewing machine which will incorporate a variable clutch to permit exact synchronization of the rotary speed of said shaft with the feed of the material through the sewing machine so that the material will travel through the attachment at the same rate as it is delivered by the feeding mechanism of the machine.

Another object resides in the provision of a novel clutch that will convert oscillating movement derived from the reciprocations of the needle bar into rotary movement having uniform direction of rotation, and which will be adjustable within a wide range, each adjustment resulting in a change in the speed of rotation of the cutting or pinking element so that the Variable capacity of the clutch will be adequate and will fulfill all requirements demanded by the feeding mechanism of the sewing machine.

A further object of the invention is to provide a cutting or pinking attachment for sewing ma- 1935, Serial No. 16,362

chines that will be operated by a moving element of the machine and which will be adjustable as to speed of rotation during operation so that synchronization with the feed of the material through the sewing machine can be easily accomplished.

The invention further contemplates an attachment of the character described that can be readily secured to a sewing machine in a plurality of adjusted positions with respect to the needle to permit the operator to vary the distance of the severed edge from the stitching, thereby cutting margins of variable width.

It is proposed that the attachment be held to the working surface of the sewing machine by a plate member iixedly secured in position on said surface and which will permit adjustment of the attachment to sever the material at variable distances from the stitching.

With these and various other objects in View, the invention may consist of certain novel features of construction and operation as will be more fully described and particularly pointed out in the specication, drawings and claims appended hereto.

In the drawings which illustrate an embodiment of the invention and wherein like reference characters refer to like parts- Figure 1 is a plan view of the attachment constructed in accordance with the invention and shown in association with the operating elements of the sewing machine;

Figure 2 is a side elevational View of the attachment showing the same equipped with a pinking element having feed rollers cooperating therewith;

Figure 3 is an elevational view of the other side of the attachment showing the operating mechanism for connecting the rotary cutting element with the sewing machine;

Figure 4 is a bottom plan view of the attachment;

Figure 5 is a sectional view taken substantially along 5-5 of Figure 4;

Figure 6 is a detailed sectional View taken along 6-6 of Figure 2;

Figure '7 is a sectional view showing details of the variable clutch included in the drive for rotating the cutting element; and

Figure 8 is a sectional View taken substantially along 8--8 of Figure 7.

The present application concerns improvements over the form of mechanism for trimming seams shown in my co-pending application Serial No. 8,626, filed February 28, 1935, particularly an face from member I8.

improved form of drive for the rotary cutting element which will provide for variations in the speed of rotation of the element to synchronize with the Various feeds of the sewing machine.

Referring to the drawings, the attachment has been shown in associated relation with certain operating parts of a sewing machine of the type adapted for home use and which consists of a work supporting surface I0, a vertical reciprocating needle bar II carrying a needle I2 and a supporting post I3, having a foot I4 secured thereto by a thumb screw I5 and which holds the material during sewing in Contact with the feeding mechanism I8 of the machine. The supporting post I3 can be vertically reciprocated byV the operator and is yieldingly held in contact with the material during the sewing operation, being lifted by the operator to remove the same from the material at the end of the sewing operation.

The attachment essentially consists of a frame member, Figure 1, which includes a vertical supporting member I8 having an inclined work supporting surface 28 secured thereto. Extending from one side of the member I8 is a boss 22 overlying but being spaced from the work supporting surface, as best shown in Figure 6. Extending from the member I8 below the work supporting surface are two spaced bosses 23 and 24, Figure 4, which bosses journal shafts to be presently described. The right- angled strap members 25 and 26 are suitably bolted to the lower portion of wall I8 and to the surface 20, said 'strap members thereby supporting said sur- Adjacent the base of said member and to the rear thereof is provided a laterally extending foot portion 2I-which extends for a part of the distance of the surface 28 to aid in supporting the frame in horizontal position on/the surface I Il of the sewing machine.

The boss 22, Figure 6, journals a shaft 28 which projects from the end of the boss and receives the washers 30, the cutting element 3I and a retaining member 32, theY parts being keyed and being held to the shaft by the bolt 33. .The opposite end of shaft 28 also projects fromthe wall I8 and has suitably secured thereto, or preferably formed integral therewith, a drum 314 as best shown in Figure 8. Drum 34 is provided with stepped surfaces, forming a reduced portion 35 which receives a ring 36 to which is suitably secured the studs 31 carrying rollers 38. Rotatably mounted on the end of shaft 28 is a disk 48 having a diameter substantially the same as the ring, which has an outside diameter the same as drum 34. Said disk provides a forwardly extending operating arm 4I, which is bent at right angles to form an intermediate section 42 which is further bent and provided with a bifurcated end 43 for engaging the stud 44. Said stud has a knurled end and is suitably secured to the reciprocating needle bar II of the machine. A block 45 is secured by the screws 46 to the inside surface of the disk 4I), the block being locked within the drum and adapted to have contact with the rollers 38 when forced into engagement therewith by the oscillation of the operating arm. The ring 35 and disk 40 are held to the drum and shaft respectively by the bolt 4l.

The cutting element 3I may take the form of a pinker for severing the material, producing an edge of irregular or wavy design, or may consist of the usual rotary knife for cutting the material on a straight edge. From the foregoing description of the drive for rotatingl the cutting element, it will be understood that vertical movement of the needle bar will oscillate arm 4l and therefore disk 40, imparting rocking movement to the block 45 xed to the disk and located within the drum 34. The ring 38 has rotation on the reduced portion of the drum and therefore the rollers 38 may be adjustably positioned so that engagement of the block with the rollers, as shown in Figure '7, may takevplace early in the down stroke of the operating arm or late in the down stroke of said arm. It will be clear from the drawings that the up stroke of the arm quickly releases the block from engagement with the rollers and returns the block to its initial position.

The ring 35 is provided with a pin 48 which extends through an arcuate shaped opening 58 formed in the disk 48. The cam 5I has contact with the pin for holding the same in the desired position within the range permitted by the slot 58, the pin being held in engagement with the cam by the coil spring 52 fixed at one end to stud 53 integral with the ring and at its other end to the frame of the attachment. The cam is journalled in member 54 secured to the frame I8 and is rotated by means of the lever 55. Member 54 provides an arcuate plate 55 having indicia thereon corresponding to the several speeds of the feeding mechanism of the sewing machine.

The variable clutch is designed to convert the oscillating movement of the arm 4I into rotary motion of a uniform direction, the motion being imparted to shaft 28 and thus to cutting element 3l. Assuming that the cam 5I has been positioned as shown in Figure 3, the pin 48 will thus be located substantially centrally of the slot 50 and the ring 38 will thus locate the rollers 38, as shown in Figure 7. With the arm 4I about to complete its up stroke, the block 45 will have a corresponding position within drum 34, as shown in Figure '1. With the pin 48 adjusted as described it will be seen that the block will have Contact with the rollers only after the arm has completed a substantial part of its downward movement. When contact of the block with the rollers takes place, they are forced into engagement with the drum 34 and the parts are in this manner locked to the disk 40. Any further downward movement of the arm will therefore rotate the drum, giving corresponding rotation tothe cutting element. Upon upward movement of the arm, the rollers release their engagement with the drum and are caused to return to their former position as the ring is biased by the spring 52. The block however continues its rearward motion until the arm reaches its upper limit of movement where the operation is again repeated upon downward travel of the arm. A flexible steel band 5l is fixed to the frame at 58 and passes over the drum, being held in contact therewith by the coil spring 58. The drum is frictionally held by the band which permits the rotation of the drum caused by the block forcing the rollers into positive engagement therewith, but which holds the drum against reverse rotation. As the rollers can be located in an infinite number of positions, the clutch is capable of driving the cutting element at any speed desired, which will range from a maximum speed in which case the drum will have full rotation for the entire downward stroke of the arm, to a minimum speed secured by locating the rollers Where the block will just engage therewith, at the extreme lower limit of the downward stroke of the arm. By proper calibration of the variable clutch, the indicia on plate 56 will indicate to the operator the proper speed for any particular positioning of the lever 55.

The work supporting surface 20 is provided with an opening directly below the cutting velement 3|, Figure 5. Part of this opening is closed by a rear apron 60 which is suitably secured as at 6| to the under side of the surface 2U. Forward of said opening there is provided a front apron 62 also suitably secured to the under side of surface 20. The free edge of said apron rests on the lower feed rollers 63 to direct the material between said cutting element and the feed rollers. Said feed rollers are journalled in a yoke 64 by means of the stud shaft 65 passing through the arms of said yoke and which shaft, at its inner end, is cut away on its lower side providing the flat surface 66, as shown in Figure 5. The yoke 64 is provided with a shaft 6l which is journalled in boss 23 of the vertical wall I8. 'I'he other end of said shaft extends beyond the boss and receives the. coil spring 68, which is retained thereon by the washer 69 and bolt l0. The coil spring therefore yieldingly holds the yoke in contact with the end of the boss 23. 'I'his is desirable as it is necessary to hold the outer of the feed rollers 63, which is provided with an upstanding edge ll, in yielding contact with a cutting knife, which, it will be understood, may be substituted for the form of cutting element disclosed. The shaft 6l also mounts the yoke within the frame so that the same may have rotation thereby supporting the feed rollers 63 for bodily movement in a direction towards and away from the cutting element. Movement of the feed rollers in this manner is likewise desirable as it is necessary that the attachment accommodate thin, light material as well as heavy, thick material and in order to apply the proper pressure on the material, a resilient member '|2 is fixed to the frame and has engagement at its free outer end with the` yoke.

The member |2 will therefore yieldingly hold the feed rollers in contact with the cutting element 3|. However, for starting the material through the attachment, it is necessary that the feed rollers be moved out of engagement with the cutting element so that the material may be. easily positioned therebetween. For accomplishing this release of the feed rollers, a lever 13 is provided, Figures 3 and 5, having the stud shaft 'I4 fixed thereto and which is mounted in the frame i8. The other end of the stud shaft connects with an arm 15, overlying the projecting end of shaft 65. Actuation of the lever in a direction to impart clockwise rotation to arm 15, Figure 5, will rock the yoke in a downward direction moving the feed rollers out of contact with the cutting element.

When the cutting element 3| comprises a pinker for severing the material on a scroll or decorative edge, it is desirable to hold the feed rollers against bodily movement, which movement is possible as above described, as the yoke 64 is journalled by the shaft 61. The invention contemplates locking means for holding the yoke against movement which consists of an eccentric '|6, Figure 6, carried by shaft journalled in boss 25 of the frame. The opposite end of the shaft has threaded thereto a knob having a portion 'i8 and a collar 88 adapted to receive a coil spring 8| having one end fixed to the boss, as shown in Figure 4, and its other end fixed to the knob. A lever 82 is fastened to the portion '|8 and projects rearwardly of the frame for engagement with studs 83. When thus engaged the eccentric |6 is held out of contact with the shaft 65 and downward movement of the yoke is possible against tension of the spring 68. However, when lever 82 is released, the spring 8| will cause rotation of the shaft 11 and location of the eccentric in firm contact with shaft 65. This locks the yoke against movement and holds the feed rollers 63 in firm contact with the pinking element, the feed rollers therefore providing a firm and unyielding foundation for the pinking operation.

The attachment of the invention is preferably held in adjustable position on the work supporting surface of the sewing machine by means of a plate member 85 which is fixedly secured to the surface l0 of the sewing machine by screws 86. Said plate 85 is provided with an edge 8l, Figure 3, bent upwardly so as to be spaced from the surface of the machine and which is adapted to fit within a groove formed in the foot portion 88 and frame |8 of the attachment. The attachment is therefore securely held to the surface of the sewing machine to the rear of and in proper relation with respect to the needle as will be clear by reference to Figure l. An extension 9i! of the plate 85 is located under the surface 20 of the attachment and is provided with indicia 8| for association with they indicating mark appearing on the face of the surface 26 at the lower edge thereof. When the attachment is moved laterally with respect to the plate 85 the indicia will indicate to the operator the distance of the cutting element from a line intersecting the needle and thus the extent of the margin that will be cut for any particular position of the attachment. The plate therefore in addition to firmly holding the attachment to the work supporting surface of the machine also provides indicia for indicating to the operator the width of the trimmed seam for any particular positioning of the attachment.

As shown in Figure 6 the cutting element is a flat rotary knife fixed to shaft 28 so as to rotate therewith and which is provided with rollers 92 having a rubber surfacing 93, the knife and rollers engaging the lower feed roller 63 to the inside of the yoke 64. From the foregoing description it will be understood that the cutting element is driven from the reciprocating needle bar of the sewing machine by the instrumentality of the arm 4| and variable clutch connecting the arm with the shaft. The clutch operates to convert the reciprocating motion into intermittent rotary movement, it being understood that the drum 34 is rotated by the downward movement of the needle bar and that the up stroke of the needle bar immediately releases the rollers 38 from engagement with the drum and returns the rollers and the block 45 to initial position. Reverse rotation of the drum is prevented by the band 51. The magnitude of the intermittent rotation of the cutting element can be varied by adjusting the position of the rollers 38 so that they are engaged by the block 45 early in the down stroke of the arm or late in said down stroke. This has the effect of varying the speed of rotation of the cutting element although the reciprocating movement of the needle bar is uniform and constant. Therefore it will be understood that by adjustment of the variable clutch as described the speed of rotation of the cutting element can be synchronized with the feeding mechanism of the sewing machine and this is possible during operation of the device. The invention also contemplates that the clutch will be calibrated whereby the operator can set the clutch by movement of the lever 55 to secure the speed desired for a particular setting of the feed mechanism of the sewing machine and which will result in exact synchronization of the attachment with the being forced into clutching engagement with the' 20 drum by movement of said arm to cause rotation of the drum and thus the cutting element, and means for varying the position of the clutching members Within the drum to vary the speed of rotation of the cutting element.

2. The combination with a sewing machine having feeding mechanism adapted to operate at variable speeds, of a cutting and pinking attachment for severing the material at a distance from the seam to produce margins of the de- 30 sired widths, said attachment having a rotatable shaft carrying the cutting element, :and

means operatively connecting said shaft with a reciprocating member of the machine including a clutch having adjustment to vary the speed 35 of rotation of the shaft so that the cutting element can be synchronized with the feeding mechanism of the sewing machine, said clutch being adjustable during operation of the attachment.

3. The combination with a sewing machine having feeding mechanism adapted to operate at variable speeds, of a cutting and pinking attachment for severing the material at a desired distance from the seam, said attachment having 45 a rotatable shaft carrying the cutting element,

and means operatively connecting said shaft with a reciprocating member of the machine including a clutch for converting the reciprocatingvmotion into intermittent rotary movement, said clutch including adjustabley clutching members to permit adjustment thereof for varying the speed of rotation .of the shaft and thus the cutting element, and means on the attachment readily accessible to the operator for adjusting the clutching members. Y

4. An attachment for sewing machines comprising a frame having a shaft mounted for ro'- tation therein, a cutting element fixed to the shaft, means operatively connecting the shaft with a reciprocating member of the machine including an arm pivoting on said shaft, a clutch between the arm and said shaft for intermittently rotating the shaft and thus the cutting element, said clutch being adjustable to vary the step-by-step movement of the cutting element to synchronize with the feed of the material through the sewing machine, and a rotatable cam carried by the attachment and being operative upon rotation thereof to effect adjustment of said clutch.

5. An attachment for sewing machines comprising a frame having a shaft mounted for rotation therein, a cutting element xed to the shaft, means operatively connecting the shaft with a reciprocating member of the machine including an arm pivoting on said shaft, a clutch between the arm and said shaft for intermittently rotating the shaft and thus the cutting element, said clutch being adjustable to vary the step-by-step movement of the cutting element to synchronize with the feed of the material through the sewing machine, means on the attachment for adjusting the clutch, and a plate fixed to said attachment and having association with said means for indicating the speed of said cutting element for any particular setting of said means.

SARAH M. CREWDSON.

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