US2881833A - Sewing machine attachment for cutting seam binding - Google Patents

Description

April 14, 1959 J. M. HOFFEE 2,881,833

' SEWING MACHiNE; ATTACHMENT FOR CUTTING SEAM BINDING Filed Sept. 14, 1955 3 Sheets-Sheet 1 \g INVENTOR.

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J. M. HOFFEE April 14, 1959 ACHMENT FOR CUTTING SEAM BINDING SEWING MACHINE ATT Filed Sept. 14, 1955 W 4 r A 6 x .n G F 0 "N u I. J m k x 7 M .U W 0 N M m w 1 k i.

2 ,3 6 M C Q 7 FIG. 8.

INVENTOR. JOSEPH M. game-E -r-roRN'aYs J. M HOFFEE 2,881,833

SEWING MACHINE ATTACHMENT FOR CUTTING SEAM BINDING April 14, 1959 s Sheets-Shee t 5 Filed Sept. 14, 1955 I N VEN TOR.

uos EPH v M. HOFFEE BY ATTORHLYS United States Patent SEWING MACHINE ATTACHMENT FOR CUTTING SEAM BINDING Joseph M. Hotfee, Nyack, N.Y.

Application September 14, 1955, Serial No. 534,367

2 Claims. (Cl. 164-175) This invention relates to accessories or attachments for sewing machines, and in particular relates to an improved attachment for severing seam binding material or other material passing through the machine.

In the garment manufacturing art, in order to sew seam binding to the edges of garments and the like, seam binding is fed through a sewing machine from a continuous roll, and garments are successively fed through the machine by the operator in position to be successively stitched to the seam binding. After a garment has been stitched to the seam binding, it is necessary for the operator to pick up another garment and feed it through the machine so that it can be sewn into the seam binding. It' is necessary to cut the seam binding between successive garments, so as to separate the garments from each other and so as to make the seam binding substantially co-extensive with the garment edge to which it is sewn.

In accordance with this invention, a cutting device is attached to the sewing machine in a suitable position so that it may be actuated to cut the seam bind-ing somewhat beyond the needle position at which it is stitched to the garment edge. Means are provided for automatically actuating said cutting means, said a-cuating means being responsive to sensing means which are adapted to sense the approach of a garment to the cutting point, and the departure of said garment from said cutting point, so

that the seam binding is cut flush with the leading and trailing edges of the garment.

An important object of this invention is to provide an improved cutting device, operating on a scissors principle, which is efficient in operation. If an ordinary scissortype mechanism is used, I have found that it takes a considerable amount of force to operate the cutting mechanism properly. However, I prefer to actuate the cutting mechanism by means of a solenoid, which solenoid may be coupled in an electric circuit with the sensing means. When a solenoid is used, means must be provided for improving the efficiency of the cutting mechanism in response to the force exerted thereon.

Accordingly, I provide bearings between the adjacent surfaces of the two scissor elements, proximate to their pivot, so that the two members ride more freely relative to each other. In addition, I provide improved means for spring tensioning the two cutting blades against each other at a point remote from the pivot point. An important feature of the invention resides in the particular means which I provide for thus spring biasing the blades toward each other, and another important feature of the invention resides in the particular manner in which the blades are shaped so that they make substantial point contact with each other in each position of the movable blade.

Another important object of this invention is to provide improved sensing means and improved actuating means for operating the blades.

In an alternate embodiment of the invention, instead l of providing automatic sensmg means, the actuating means are controlled by a manual micro-switch which is placed 2,881,833 c Patented Apr. 14,

so as to be readily accessible to the operator for closure thereof at the proper time.

Other objects and advantages of this invention will become apparent from the following description, in conjunction with the annexed drawings in which preferred embodiments of the invention are disclosed.

In the drawings,

Fig. 1 is a top plan view of the improved attachment, showing also a portion of the sewing machine upon which the attachment is mounted.

Fig. 2 is a front elevation of the attachment.

Fig. 3 is a section on line 3--3 of Fig. 2, showing in particular the sensing means.

Fig. 4 is a section on line 4-4 of Fig. 2. N

Fig. 5 is a fragmentary rear elevation of the attach: ment, showing details of the cutting blades.

Fig. 6 is a section on line 66 of Fig. 5.

Fig. 7 is a schematic circuit diagram of the electric control circuit of the attachment.

Fig. 8 is a top plan view, similar to Fig. 1, of a secon embodiment of the invention, showing a manually operated micro-switch for controlling the operation of the cutter.

Fig. 9 is a front elevation, similar to Fig. 2, of the second embodiment, and is partially broken away. Fig.9 also shows schematically the electric control circuit of this embodiment.

First embodiment My improved attachment includes a base plate 10 which is adapted to be fixed to the sewing machine table (not shown) by means of screws 11 or other suitable fasten ing means. The exact manner of mounting the attachment is not important, as long as the parts of the attachment are located properly in relation to the needles and presser foot of the sewing machine. Fig. 1 shows somewhat diagrammatically the double needles 12 of the sewing machine, and the presser foot 13 of the sewing machine. Said presser foot 13 is mounted upon the sewing machine shaft 14 by means of set screws 15 or the like. Said needles 12 and said presser foot 13 are operated in the conventional manner by the sewing machine to perform the usual stitching operations upon the seam binding tape 16 and the successive garments 17a and 17b. In particular, the arrow designated by the reference numeral 18 shows the direction in which the tape 16 and the garments 17a, 17b, etc., are fed. Arrow 18 is assumed to point from front to rear.

It will be apparent that the tape 16 may be fed in the front to rear direction of arrow 18, by any suitable means (not shown). In the following description, it will be as sumed that the successive garments or the like 17a and 17b are fed successively into the front of the machine, by the operator, and are carried by the machine front to rear in such a manner that the two needles 12 stitch the tape 16 to the garment along parallel lines of stitching 19. However, it will be understood that the exact manner in which the garments are fed does not form a part of this invention.

As is best shown in Figs. 1, 2 and 4, a conventional solenoid 20, including a solenoid coil 21, is mounted upon the upper face of plate 10 by means of spacer sleeves 22 and screws 23, or by any other suitable means. Said solenoid 20 includes a plunger 24 which operates along a lateral axis. When solenoid coil 21 is energized, plunger 24 is adapted to be moved from right to left, as taken in Figs. 1 and 2.

A frame 25 is mounted upon plate 10, to the left of solenoid 20. This frame 25 includes a front arm 26, a rear arm 27, a right longitudinal arm 28 and left longi- 0 tudinal arms 29 and 32. Said frame 25 is generally rectangular in shape, as viewed in top plan (Fig. 1). Arm

of longitudinally elongated and longitudinally spaced slots 30. Ann 28 is optionally secured to plate by means of screws 31 which respectively extend through slots 30, so as to permit longitudinal adjustment of frame relative to plate 10 and also relative to the presser foot 13. As a result, when plate 10 is mounted upon the sewing machine table, it is possible to locate the cutting blades of the attachment in the desired longitudinal position behind presser foot 13.

The shape of front arm 26 is best shown in Fig. 2. As shown in Fig. 2, said arm 26 is optionally stepped downwardly at 26a to the left of plate 10, so that the upper face of arm 26 and plate 10 become approximately coplanar. As best shown in Fig. 3, the left arm 29 is fixed to the left end of arm 26 and is substantially planar. On the other hand, arm 27 is sharply stepped upwardly at 27a, adjacent the end of plate 10, so that arm 27 is elevated substantially above the height of arm 26 and arm 29. The short arm 32 is fixed to the left end of arm 27 and extends forwardly for a short distance therefrom. The front end of arm 32 terminates in a forwardly downwardly inclined bracket arm 33 which is located above arm 29 and adjacent the rear end of arm 29.

The garment-sensing means include a mirror 34 fixed to the top of arm 29, and a photo-cell unit 35 fixed to the front face of bracket arm 33. Said photo-cell unit 35 is a conventional unit and has a pair of bores 36 and 37 which respectively extend forwardly and rearwardly downwardly, terminating at the bottom face of the unit 35, as is clearly shown in Fig. 3. Photo- cells 38 and 39 are respectively located within bores 36 and 37 and are adapted to receive light at their bottom faces. Said photo-cell 38 has appropriate leads 40 and 41 which are drawn up through the upper face of unit 35 and which are adapted to be connected in the electric circuit of Fig. 7. Similarly, photo-cell 39 has suitable leads 42 and 43.

Unit 35 has a central vertical bore in which a lamp unit 44 is located. Said bore 45 extends to the lower face of unit 35. Said lamp 44 has input leads 46 Mirror 34 is attached at its respective front and rear ends to arm 29 by means of screws 47 or the like. Said mirror 34 has wings 34a which diverge downwardly from the center of the mirror to the end portions thereof. Lamp 44 is adapted to emit a beam of light 48 downwardly onto the center of the upper face of mirror 34 and hence upon the respective wings 34a. Accordingly, reflected beams of light 49 are respectively directed up wardly into the respective bores 36 and 37 and hence upon the respective light receiving faces of photo- cells 38 and 39. Accordingly, if unit 35 is in operation, the cells 38 and 39 are respectively energized unless material passes over mirror 34 and hence simultaneously blocks the passage of light between the lamp 44 and the cells 38 and 39.

The knife The fixed knife blade 50 is fixed to plate 10 slightly behind arm 26, by means of screws 51 or the like. Said blade 50 is preferably made in a single piece and includes a head portion 52 which is attached to plate 10 by means of the aforesaid screws 51. Said blade 50 extends to the left from its head 52 and has a rear cutting face 53. The upper edge 54 of said face 53, which is the actual cutting edge of the blade, is inclined slightly downwardly from right to left. Said face 53 is slightly undercut, as viewed in Fig. 4, to make certain that the movable blade makes contact with the fixed blade substantially only at said cutting edge 54.

Movable blade 55 includes a generally horizontally extending cutting blade arm 56 and a generally vertically extending arm 57 integral with said arm 56 at the right end thereof. Said blade 55 is pivotally attached to the rear face of head 52 of fixed blade 50, at the junction area of arms 56 and 57.

In order to attach blade 55 pivotally to blade head 52, a bore 58 is provided in head 52, and a throughand-through bore 59 of increased diameter is provided in blade 55. This is clearly shown in Fig. 6. A stud 60 has a head 61 located rearwardly of blade 55, a shank 62 extending frictionally turnably through bore 59, and a screw-threaded shank extension 63 which is adapted to be screwed into the correspondingly screw-threaded bore 58. In this manner, shank 62 abuts against the rear face of the blade head 52, and the front face of head 61 is spaced from the rear face of head 52. Shank 62 is slightly longer than the thickness of blade 55 so that blade 55 has a limited amount of play between the proximate faces of shank 62 and head 52.

A plurality of ball bearings 64, optionally three in number, are partly turnably located in appropriate recesses 65 in the front face of blade 55, to the right of pivot shank 62, as viewed in Figs. 1 and 2, and as shown in Figs. 5 and-6. These balls 64 bear turnably frictionally against the rear face of the blade head and reduce the force required to turn blade 56 relative to the fixed blade 50. These balls 64 are preferably vertically spaced, as shown in Fig. 5.

Screw 66 has a head 67, a shank 68 and a screwthreaded shank extension 69 of reduced diameter which is adapted to be screwed into a corresponding screwthreaded recess in the rear face of head 61. In this manner, head 67 is spaced from head 61.

A bracket comprising a lateral bracket arm 70 and a longitudinal bracket leg 71 is mounted upon shank 68. Bracket leg 71 extends forwardly from the right end of bracket arm 70. Arm 70 has an opening 72 through which said shank 68 extends. Leg 71 abuts the right face of head 61, and bracket arm 70 extends to the left of screw 66, as viewed in Figs. 1 and 2.

A strong tension spring 73 made of suitable metal includes a right arm portion 74 which has an opening 75 through which shank 68 extends. This arm portion 74 is slightly inclined rearwardly from right to left, and its right end abuts the upper face of head 61. Said arm 74 is located in front of and in longitudinal registration with bracket arm 70.

A generally U-shaped bracket 76 includes a vertical rear leg which rests against the rear face of bracket arm 70, and top and bottom horizontal guide arms 77 which respectively extend above and below and forwardly of the side edges of bracket arm 70 and spring arm 74. A threaded screw shank 78 extends forwardly through an aperture 79 in bracket 76 and is screwed into and forwardly of an appropriate screw-threaded aperture in bracket arm 70. The front edge of said shank 78 abuts the rear face of spring arm 74, to the left of shank 68, as viewed in Figs. 1 and 2.

It will be apparent that the tension of spring 73 may be adjusted by turning screw shank 78 in the appropriate direction. The screw head 80 is spaced rearwardly of bracket 76 and a tensioning coil spring 81, which is mounted upon shank 78 between bracket 76 and head 80, serves to keep the screw from working loose from vibration.

Said spring 73 extends forwardly from the left end of spring arm 74, to join the left spring leg portion 82 which bears against the rear face of blade 55. A screwthreaded stud 83 extends through an opening 84 which is formed in spring arm 82. This opening 84 is elongated in the direction of length of spring arm 82. Said stud 83 is screwed into an appropriate screw-threaded recess in blade 55, to serve as a guide to maintain spring 73 in registration with blade 55.

Said spring 73 serves to urge the outer end of blade 55 forwardly so as to provide effective blade contact during the cutting motion.

The lower face of blade arm 56a is optionally and preferably slightly convex in the direction of its length as shown in Figs. 2 and 5, and is also slightly rearwardly upwardly inclined, as shown in Fig. 4, so that the front cutting edge 56b of said cutting surface 56 makes substantial point contact with the cutting edge 54 of the stationary blade 50.

As shown in Fig. 6, in the normal position of the movable blade (shown in Fig. 5 and in other views), the cutting edge of the movable blade overlaps the cutting edge of the fixed blade, as viewed from above, so that the two cutting edges make point contact near the pivot point of the blades. During the cutting action, the point of contact moves progressively outwardly toward the free end of the blades, until the respective blade surface 53 and the rear face of blade 50 about each other at the conclusion of the stroke. During this cutting action, the right end of blade 55 (where the bearings 64 are located) tends to move toward the blade face 53 of blade 50, but the action of bearings 64 prevents binding at this point. The action of screw shank 78 upon spring legs 74 and hence upon head 61 prevents loosening of screw 60. The bracket arm 71 and the bracket arms 77, as well as pin 83, prevent spring 73 from shifting out of alinement relative to screw 78 or blade 55.

The front end of plunger 24 is coupled to the right face of upright blade arm 57 by means of a suitable compression spring 85 which is connected to the two members by any suitable means. As a result, during the letter operating stroke of plunger 24, arm 57 is forced to the left and blade arm 56 is forced downwardly, in the cutting action. A return spring 86 is connected between the top of the frame of solenoid 20 and the top of arm 57, as shown in Figs. 1 and 2, so that when the solenoid is deenergized said spring 86 returns blade 55 to its position of Fig. 2, in the right or return stroke of plunger 24.

It will be apparent that this construction provides an extremely efiicient cutting action of the blades. In the cutting stroke, cutting edges 56b and 54 makes substantially only point contact in each position of the movable blade. The use of the bearings 64, in addition to this point contact, makes it possible to drive the movable blade in its cutting stroke with relatively little force, and yet to provide an efiective cutting action upon the cloth of the tape 16. Furthermore, the spring 73 acts to hold the blades close together, against the action of the tape 16 and also tends to prevent the bearings 64 from binding.

' A cloth guide 87 is attached to the front face of block 52, by means of screws 87a, and extends vertically and laterally. Forwardly of block 52, said guide is provided with a rearwardly extending lower flange 88 which is spaced slightly above the fixed knife blade 50 as shown in Fig. 4, but which does not extend quite as far as the plane of the front face of the movable blade 56. This prevents any cloth being fed into the attachment from riding up over the movable blade and requires the cloth to move in a path between the two blades.

The electric circuit As shown schematically in Fig. 7, the attachment is wired to provide a pair of input leads 90 and 91 which are adapted to be connected to a suitable source of a1- ternating current. Optionally, one of said leads 90 is connected by fuse 92 and manual switch 93 to a further lead 94. Said lead 94 is connected to a further lead 95 and said lead 91 is connected to a further lead 96. These leads are connected across the primary 97 of a transformer, and the leads 46 of lamp 44 are connected .to the respective ends of the secondary 98 of said transformer. Accordingly, lamp 44 is in operation whenever switch 93 is closed. Lead 95 is connected to one end of solenoid coil 21, and relay switch 99 is connected between the other end'of solenoid 21 and said lead 96. Accordingly, when the relay switch 99 is closed, coil 21 is energized.

'Line 91 is also connected through line 96 to one side of a voltage doubler and line 94 is also connected to another side of said voltage doubler. Said voltage doubler includes a pair of crystal rectifiers 100 and 101. The negative terminal of rectifier 100 is connected to line 96, and the positive terminal of rectifier 101 is connected to line 96. A pair of condensers 102 and 103 are connected in series between the positive terminal of rectifier 100 and the negative terminal of rectifier 101 and line 94 is connected to the junction between condensers 102 and 103. Preferably, the source of alternating current is 115 volts cycles. It will be apparent that nominally 230 volts DC. current are developed between the positive terminal of rectifier 101 and the negative terminal of rectifier 101.

A filter resistor 104 and a filter condenser 105 are connected in series between the positive terminal of rectifier and the negative terminal of rectifier 101. The positive line 106 is connected to the junction between resistor 104 and condenser and the negative line 107 is connected to the negative terminal of rectifier 101. Voltage divider resistors 127, 128 and 116 are connected in series between lines 106 and 107.

I preferably utilize in this circuit a twin triode 108 which contains plates 109 and 109a, grids 110 and 1100, cathodes 111 and 111a and filaments 112 and 112a. Said filaments 112 and 112a are optionally connected in parallel, and leads 46 are connected by lines 113 across said filaments in order to provide the necessary filament current during operation of the device.

Plate 109 is connected through relay coil 114 and line 115 to the positive line 106. Plate 109a is connected through relay coil 114a and line 115a to said positive line 106. The negative line 107 is connected through resistor 116 and respective resistors 117 and 117a to the respective cathodes 111 and 111a. Accordingly, the plate voltage is determined by the voltage drop across resistors 127 and 128. The photo-cathode 39 is connected by lead 43 and resistor 118 to line 106, and is connected by lead 42 and variable resistor 119 to negative line 107. Grid 110 is connected by line 120 to lead 42.

Similarly, photo-cathode 38 is connected by lead 41 and resistor 11811 to line 106, and is connected by lead 40 and variable resistor 119a to line 107. Grid 110a is connected by line 120a to lead 40.

It will be apparent that the principle of operation of both halves of tube 108 is the same. Taking, for example, the left hand triode, it will be apparent that resistor 118, photo-cathode 39 and resistor 119 serve as a voltage divider circuit, such as to tend to provide positive bias on grid 110. On the other hand, the cathode resistor 116 serves to provide a negative grid bias. Resistor 119 is optionally and preferably adjusted so that when photocathode 39 is energized, the resulting grid bias developed across said resistor 119 opposes the cathode bias sufficiently to provide a net grid bias which permits substantial plate current to flow. However, when photo-cathode 39 is inactive, so that no bias is developed across resistor 119, the negative bias developed across resistor 116 is sufficient to prevent the triode from drawing any substantial amount of plate current. As a result, relay coil 114 is energized only when photo-cathode 39 is energized.

Similarly, relay coil 114a is energized only when photocathode 38 is energized.

Fig. 7 shows the relay contacts in their positions when photo- cathodes 38 and 39 are not energized. In this condition, the movable contact arm 121 associated with relay coil 114 engages the fixed contact 122, and similarly the fixed movable relay contact 121a associated with relay coil 114a engages the fixed contact 122a. The fixed contacts 123 and 123a respectively associated with coils 114 and'114a are open. The movable contact 121 is connected by line 124 to the negative line 107. The movable contact 121a is connected by line 125 to one terminal of an auxiliary relay coil 126. The aforesaid relay switch 99 comprises the respective fixed and movable contacts associated with relay coil 126, which are normally open. The other terminal of relay coil 126 is connected to the junction between resistors 127 and 128. Contacts 122a and 123 are connected by line 129. Contacts 122 and 123a are connected by line 130.

In the position of Fig. 7, line 125 is not connected to line 124, because contacts 121 and 123 are open, even though contacts 121a and 122a are closed. Similarly, if both photo- cathodes 38 and 39 were energized, thereby closing contacts 121 and 123, closing contacts 121a and 123a, opening contacts 121 and 122, and opening contacts 121a and 122a, line 125 again would not be connected to line 124. However, if photo-cathode 39 is not energized and photo-cathode 38 is energized, then contacts 121 and 122 are closed, and contacts 121a and 123a are closed, so that line 125 is connected to line 124. A similar result occurs if photo-cathode 39 is energized and photo-cathode 38 is not energized.

When line 124 is connected to line 125, current flows from line 106 through limiting resistor 127, relay coil 126 and lines 125 and 124 to line 107.

It will be apparent, therefore, that relay coil 126 is energized when either of the photo-cathodes is energized, but is not energized when both photo-cathodes are energized or when both photo-cathodes are not energized. When relay coil 126 is energized, relay switch 99 closes, solenoid coil 21 is energized, and the cutting operation takes place.

Relay 126 is a slow acting relay, so that it is energized sufliciently long to permit the blades to complete their cutting stroke. However, it is deenergized sufiiciently soon to permit the blades to return to their normal position as soon as they have completed the cutting stroke.

Summary of Operation Fig. 1 shows garments 17a and 17b just after the binding 16 has been cut at the rear edge of garment 17a. At this instant, garment 1711 has not yet reached the cutting attachment, and accordingly neither of the light beams 49 are blocked, so that both photo- cells 38 and 39 are energized. In this condition, contacts 121 and 123 are closed and contacts 121a and 123a are closed. As explained above, the electric circuit of relay coil 126 is not completed, relay switch 99 is not closed and solenoid 20 is inactive. For convenience of illustration, the spacing between garments 17a and 17b is somewhat exaggerated.

At the instant that garment 17]) passes over the front mirror portion 34a, the light rays 49 to photo-cathode 39 are blocked, while the light rays 49 to photo-cathode 38 remain unblocked. As a result, relay contacts 121 and 122 are closed, and relay contacts 121a and 123a are closed. This completes the circuit of relay coil 126, and solenoid coil 21 is energized. As a result, blade 55 moves in its cutting stroke almost instantaneously and the cutting edges 54 and 56b sever the tape 16 substantially at the leading edge of the garment 1711.

While the cutting stroke, or at least the return stroke, of blade 55 is taking place, garment 17b blocks the light of both photo-cathodes, and the relay contacts 121 and 121a assume their positions shown in Fig. 7, in which the relay coil 126 is inactive. Therefore, while garment 17b is passing over both mirror surfaces 34a of mirror 34 no cutting action can occur. The instant that the trailing or front edge of garment 17b passes the front mirror surface 34n photo-cathode 39 is energized. As a result, contacts 121 and 123 are closed, and contacts 121a and 1220: are closed. Relay coil 126 is energized and another cut takes place, severing the tape 19 substantially at the front ed e of garment 1712.

During the cutting stroke of blade 55, or at least during the return stroke thereof, the front or trailing edge of garment 17b clears both of the mirror surfaces 34a and 34/), and both photo- cathodes 38 and 39 are again energized, preventing further cutting action.

No additional cut can take place until the operator starts to feed the next garment through the machine and this next garment first cuts off the light from the front mirror surface 34a.

Second embodiment This embodiment is quite similar to the first embodiment, except that the cutting operation is actuated manually by means of a micro-switch rather than automatically by means of the photo-cathode unit shown in Fig. 3.

In the second embodiment, guard 87 has a curved extension 89 which extends from the left end of guard 87 rearwardly past the scissor blades. An upstanding bracket 200 is fixed to guard portion 89 by any suitable means. A micro-switch 201 is fixed to the left face (as viewed in Figs. 8 and 9) of bracket 200 by any suitable means.

Switch lever 202 is attached to the front of the housing of micro-switch 201, by pivot means 203. Switch lever 202 is connected to pivot means 203 so as to depend therefrom and so as to be turnable about a lateral axis. Said micro-switch 201 is normally open. When the lower end of lever 202 is pushed rearwardly micro-switch 201 is closed. Upon release of lever 202, it is automatically moved forwardly to switch opening position. Microswitch 201 is conventional and is not described in detail.

A laterally extending actuating bar 204 is attached to the front of guard 87 by means of screws 205, 206. Screw 206 extends through the right end of bar 204 and is screwed through a suitable opening in guard 87. Said screw 206 is provided with a suitable spacer shank to space its head through guard 87. Screw 205 is similar to screw 206 except that it extends through bar 204 at a point slightly to the left of screw 206 and its shank is optionally slightly longer than the shank of screw 206.

Said bar 204 extends across and forwardly of switch lever 202. It will be apparent that after a garment passes through a sewing machine along with tape 16, the operator need merely push bar 204 rearwardly in order to engage lever 202 and push it rearwardly, thereby closing micro-switch 201. Bar 204 is moved forwardly in the return stroke of lever 202.

One of the terminals of micro-switch 201 is connected by line 207 to one terminal 208 of solenoid coil 21. The other terminal of micro-switch 201 and the other terminal 209 of solenoid coil 21 are respectively adapted to be connected by the respective lines 210 and 211 to a suitable source of electric current, preferably 60 cycles, volts.

As a result, it will be apparent without extended discussion that when the operator flips bar 204 rearwardly, solenoid 20 is energized to drive blade 55 in its cutting stroke. Since the operator only strikes bar 204 momentarily, lever 202 immediately returns to its normal p0sition, carrying bar 204 back to its normal position, and thus preventing a second cutting stroke.

While I have disclosed a preferred embodiment of my invention and have indicated various changes, omissions and additions which may be made therein, it will be apparent that various other changes, omissions and additions may be made in the invention without departing from the scope and spirit thereof.

Iclaim:

1. A scissors comprising a first blade having an inner face, a pivot member fixed to the inner face of said first blade, said pivot member having a shank which abuts said inner face of said first blade and a head of enlarged (11ameter which is spaced from said inner face of said first blade, a second blade having an aperture through which said shank of said pivot member extends turnably, said inner face of said second blade being located proximate to the inner face of said first blade, said inner faces of said blades having cooperating cutting edges extending away from one side of said pivot member, the length of said shank being slightly greater than the thickness of said second blade, anti-friction members mounted upon the inner face of said 2,ss1,sss

second blade adjacent the side of said pivot member which is opposite to said cutting edges, said anti-friction members slidably and frictionally abutting the inner face of said first blade, a stud fixed to the head of said pivot member and extending outwardly therefrom, an elongated blade spring having an aperture adjacent a first end thereof through which said stud extends turnably, said first end of said blade spring abutting the outer face of said head of said pivot member, said blade spring having a second end which abuts the outer face of said second blade at a point spaced from said pivot member and opposite said cutting edge, and means mounted upon said stud which are positioned and adapted to bear against said blade spring intermediate its ends to maintain it frictionally in its positions of abutment with said head of said pivot member and said outer face of said second blade.

2. A scissors according to claim 1, said stud having a head of enlarged diameter which is spaced from the head of said pivot member, said last-mentioned means comprising a bracket, said bracket comprising an arm having an aperture through which said stud extends, said arm having a further screw-threaded aperture positioned opposite an intermediate point of said blade spring, and a screw threaded through said threaded aperture, one end of said screw frictionally abutting the outer face of said blade spring, said screw holding said bracket arm in abutment with the inner face of the head of said stud.

References Cited in the file of this patent UNITED STATES PATENTS 826,587 Linscott July 24, 1906 1,885,754 Nachtigall Nov. 1, 1932 2,130,539 Feather Sept. 20, 1938 2,135,911 Ostberg Nov. 8, 1938 2,239,851 Lincoln Apr. 29, 1941 2,293,688 Allen Aug. 18, 1942 2,333,892 Schubert Nov. 9, 1943 2,361,052 Patterson Oct. 24, 1944

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