US1388411A - Trimming mechanism for sewing-machines - Google Patents

Description

A. H. DE VOE. TRIIMMING MECHANISM FOR SEWING MACHINES. APPLICATION FILED sum 10, 1911.

1,388,41 1. Patented Aug. 23, 1921.

2 SHEETS-SHEET I.

wrrNEss v I a $2 fly! v ATTORNEY A. H. DE VOE. TRIMMING MECHANISM FOR SEWING MACHINES. APPLICATION FILED SEPT 10, 1911.

1,388,41 1 Patented Aug. 23, 1921.

2 SHEETS-SHEET 2.

INVENTOR WITN E55 M ATTORNEY UNITED STATES PATENT OFFICE ALBERT 11. DE VOE, or WESTFIELD, NEW JERSEY, AssIGNoR TO THE SINGER MANU- FACTURING COMPANY, A CORPORATION OF NEW JERSEY.

'mmmme MEcHAmsMroa SEWING-MACHINES.

To all whom it may concern-1 Be it known that I, ALBERT H. DE Von, a

citizen of the United States, residing at lVestfield, ii the county of Union and State.

of New Jersey, have invented certain new and useful Improvements in Trimming Mechanism for Sewing-Machines, of which the following is aspecification, reference being had therein to the accompanying. drawings. V

' This invention relates to sewing machines and particularly to a fabric severing device for use in connection therewith.

It has for its objects the construction of a fabric severing mechanism which is compact and durable; which is applicable to certain existing machines with little or no'structural changes beyond a re-arrangement of parts;

. which may be thrown into and out of cutting position; which will not crowd the material in a direction opposite to the feed and thereby form wrinkles at the time the work is being sewed; which is powerful and smooth running; and finally which may be readily adapted to pierce and trim the under of superimposed layers of material.

Essentially the trimming mechanism com prises relatively movable ledger and cutting blaees actuated from below the cloth surface through mechanism permitting them to be moved into and out of effective cutting relation. I A latch-lever is pivoted on the bed of the machine and has a laterally extending pin which is spring-pressed into engagement with either of two slots in a fulcrum-plate hinged on the main-shaft of the machine. Below and parallel with the main-shaft of the machine a stud extends laterally from the fulcrum-plate and pivotally supports a lever which is oscillated from an eccentric on the main-shaft of the machine through the medium of an eccentric strap having a sleeve which slides on a pin carried by the lever. Knives are carried. by the lever and strap, respectively, the lower knife, which is on the lever, being substantially flush with the work-sustaining surfacewhen in cutting poof the presser-foot and Fig.

Specificationof Letters Patent. I Patented A g; 23, 1921 Application filed September 10, 1917. Serial No. 190,451.

latch-lever is in one or the other of the slots 1n. the fulcrum-plate it holds the trimming mechanism ineffective or ineffective fabric severing position as the case may be.

, The invention further consistsin certain details of construction which will appear in the following description of the figures of the drawings in which Figure 1 is an end elevation of the machine, parts below the work-plate being shown in section. Fig. 2 is a plan view of the parts'below the bedplate of the machine. F igf3'is a side elevation of the trimmingmechanism viewed in the opposite direction from Fig; 1'. F igxt is a perspective view of the eccentric strap. Fig. 5 is a perspective view of the carrier for the upper blade; Fig. 6 is a perspective of the fulcrum-plate and latch-lever. Fig.6 is a perspective view of a modified form of fulcrum-plate and latch-pin for use on machines trimming the u-nder of superimposed layers of materlal. Fig. 7 is a plan view of the throat-plate. Fig. 8 is a perspective view 9 shows a piercing blade.

The invention, which obviously may be applied to almost-any of a great variety of sewing machines, is shown as embodied in a chain-stitch machine having, above the throat-plate 1, a needle 2 carriedby a needlebar 3 which is actuated in any suitablemanner. A presser-bar 4, which may be manipulated by the lifting lever 5 in a manner well known, carries at its lower end the presserfoot 4' provided with a key-hole shaped needle and thread passage 6, Fig. 8. Forward of the needle the foot is transversely,

cut out to receive the shank 7 of an auxiliary presser-member, adjustment being afforded by the slot 8 in'the shank which receives the clamp-screw 9 tapped into the presser-foot. Extending from the shank rearwardly is a slottedportion 10 through which plays an upper fabric severing member or blade 32 (to be described). f

The throat-plate 1. Fig. 7, is suitably'cut away asindicated at 11 and 1]. to receive the feed-dog 18 and the upper trimming member 32 which pass upwardly therethrough when operating upon the fabric. 'A needle-hole 11" is also provided in the throat-plate and is shown elongated to permit basting. Below the slotted portionlO of the presser-foot the throat-plate is dished or depressed as shown at 12 to permit downward deflection of the for severing the fabric.

fabric being operated upon by the upper ber 3 Below the cloth surface, which is co-planar with the throat-plate 1, is located the main shaft 13 of the machine from feedingand lifting eccentrics 14'and 15 on which a rocking frame 16 and a feed-dog supporting bar 17 respectively, are actuated to impart the usual feeding movements to the feed-dog 18. A looper 19 on a carrier 20 is. slidingly pivoted bya sleeve 21 to a stud22 carried by a bearing lug 23 and a pin 24 fixed to'the sleeve 21 is received within a socket 25 on the eccentric strap 26 embracing an eccentric also on the main-shaft for imparting endwise and sidewise movements to the looper to effect a cooperative stitch-forming action with the needle in a manner well understobd and fully described in my Patent No. 1,085,801 granted February 3, 1914.

Between the feeding and lifting eccentrics 14 and 15' on the main-shaft is located another eccentric 30 with a rim 30 from which eccentric the fabric severing or trimmingfblades derive their relative movement 7 The eccentric 30, Fig.3, is embraced by a strap 31 on which an upper blade 32 is mounted in a manner to be described later. The eccentric strap is provided with a substantially vertically extending socket 33 which slidingly embraces a pin 34 fixed in any suitable manner as by screws 35 and 35 in a rocking lever 36 which is pivoted on a movable fulcrum-stud 37 normally below and in parallelism with the main-shaft 13 of the machine. This stud may be moved about the main-shaft as an axis to throw the trimmer into or out of active position as will presently appear. The

I rocking lever'36 is irregular in shape, in. side elevation appearing like a very wide letter U on edge so as to extend partly around the main shaft of the machine. In its head portion a lower or ledger blade 32 is secured in a manner to be described later. At its lower endthe rocking lever 36 is provided with a split tubular. boss 38 in which is clamped by a screw 39 a bearing sleeve 40 which embraces the fulcrum-stud 37 carried by the fulcrum-plate41. A screw 42, Fig. 1, is threadedinto the stud 37 and its relatively large head holds the sleeve loosely against the fulcrum-plate and prevents endwise movement thereof whereby the rocking lever and eccentric strap are constrained to move in a vertical plane transverse to the axis of the mairrshaft and substantially parallel'with the endwise movements of the loo er.

rom the foregoing it will be clear that the eccentric strap is compelled to maintain a definite angular relation to the rocking lever and that the horizontal throw of the eccentric therefore imparts movements of substantially equal amplitude to both blades.- .In other words both blades move substancourse-the upper blade infact moves in a somewhat distorted elliptical path which is .the resultant of thecombination'of the horizontal and vertical components of the throw 1 of the eccentric. It is to be observed that when the upper blade is descending and cutting fabric during the last part of its down.- ward movement, its motion-which rela'-' tive to the pin 34 and lower blade 32' is a simple harmonic motiorr-is uniformly retardedthereby answering the requirements of the work which at this time in the severing operation demands more power.

' For securing a saw-cut 45, Fig. 1, is provided in the upper free end of the rocking lever 36 adjacent a dove-tailed guide-way 46, a screw 47 permitting the walls of the guide-way being clamped against the beveled edges of the blade 32'. The blade is ground as shown so that its upper edge will be nearly parallel with the throat-plate. V

The upper cutting blade 32 is yieldingly the lower blade in position and adjust-ably secured to the eccentric strap 31, Fig. 4. To this end said strap carries a pair of. spaced bearing lugs 50, slidably receiving a short tubular sleeve 51, Fig. 5, which-fixedly carries at one end a head or carrier 52 that is cut away to form a channel 53 which is closed by a plate 54 cl amped to the head by screws 55. The head 52 is held in a nearly vertical position by a pin 56, Fig. 1. carried by the strap 31 and entering slot 57 in a depending portion of the head. The upper blade 32 is positioned within the closed channel 53 formed by the plate and the groove in the head and a wear-plate 58 is positioned against the blade to recelvc thethrust of a pin 59 carried by the tubular sleeve 51, the said pin being jammed against "spring bears against a lug 50 while its other end thrusts against a collar 63 which is provided with a screw 64 for clamping it to the sleeve 51 in order to permit regulation of the tension with which the movable blade fixed in the head is held against the lower blade by the coiled spring.

The device for locking the blades either effective or ineffective position Without alteration of their operative connection to the actuating-eccentric willnow be described.

Thetulcrunrpla te 41 carrying the stud 37 on which the rocking lever is oscillated is provided with-a bearing boss 70, Fig. 2, journaled in the bracket 71 extending upwardlyfrom the bedplate, said boss for convenience in manufacture affording a bearing bushing for. the main-shaft of the machine. which passes through it. The fulcram-plate 41 is provided witha pair of stop-shoulders 7273, Fig. 6, at the opposite ends of a portion ,74 concentricwit-h the main-shaft of the machine, and slots 75 adjacent said shoulders receive a latch pin 76 extending laterally from one side of a latchlever 77 in the opposite side of which is tapped, as indicated at 78, a shouldered plate, the latch-pin 76 is clear of the path of movement of the concentric portion 74 but not of the stop-shoulders 7273 on the fulcrum-plate and the latter may then be rotated about the main-shaft as'an axis until one or the other of the stop- shoulders 72, 73 strikes the latch-pin 76 when release of the lever 77 will carry the latch-pin into a slot 7 5 and hold the fulcrum stud 37 on the plate 41 against further movement in either direction about the main-shaft.

Friction between the eccentricstrap and the eccentric when the parts have been run ning for some time and are worn smooth cannot with certainty be relied upon to swing the rocking lever 36 and fulcrumplate 41 to a position in which the trimming mechanism is effective or ineffective, although in amachine before it has been run in it seems to be sufiicient to accomplish this result. At all events, to insure the swinging of. the trimmer outot' or into effective position, it is to be deemed advisable to provide a friction device which will render certain the control of the position of the trimming. mechanism.

For this purpose in advance of the carrier or head holding the upper n1ovable blade the eccentric strap 31 in Figs. 2, 3 and 4, is provided with a lug which is apertured horizontally in paralleism with the main-shaft as indicated at 85 to receive a hinge-pin 86 held against ,endwise movement in the lug by the collar 87 fixed on one end and by the angular block 88 fixed on its other end. In this blockis suitably mounted a friction roller 89 adapted to bear against 7 the actuating eccentric 30, theeccentric strap 31 being cut away as shown at 89 for this purpose. The upper face 90 of the block 88 when in operative position as shown in Fig. 3 in solid lines, is'so located that a light spring 91 fixed in the eccentric strap at one end bears down upon the block 88 at its other end with suflicient force to turn ;itabout the hinge-pin 86'as an axis and to urge the roller in a direction toward the line joinin the axes of thehiuge-pin and the main-shaft of the machine.

Supposing the blades are in'fabric-cutting position as shown in Fig. 1 and it is desired to throw them out of effective position, the operator stops the machine and turns it backward in a direction opposite to that indicated by the arrow in Fig. 3. Thereupon the roller 89 is carried inward toward a line connecting the axes of the hinge-pin 86 and main-shaft 13 producing by its t0gglelike action sut'ficient friction between the strap and eccentric to cause them to move together and carry the rocking lever to an inefl'ective cutting position which is predetermined by the lower stop-shoulder 73 on the fulcrumplate 41. It is to be noted, however, that the roller cannot approach close enough to a line connecting the axes of the hinge-pin 86 and main-shait 13 to jam. hen the latch-pin 7 6 strikes the shoulder 73 the frictional movement of the strap and theeccentric in unison is halted. lVith the parts in the position they have now arrived at and upon release of the latch-lever by the operator the trinnner-blade is secured in ineffective position.

It will be seen that the eccentric 30 and lug 37 form shiftable pivots for the respective blades 32 and 32, the shif ing of the eccentric actuatin the blades, and the shifting of lug 37 as shown in Fig. 3 rendering the blades inoperative.

The blades may be thrown into effective cutting position at will dur ng the operation of the machine by merely depressing the latclrlever 77 when the friction between the strap and rapidly rotating eccentric augmented by the spring-pressed roller 89 hearing upon the eccentric will be suflicient to swing the rocking lever up into its normal operative position.

The angular block 88 is provided with a second face 952 at substantially right angles to the face 90 so that the hinge-pin may be swung in a clockwise direction as viewed in Fig. 3 and held in a position with the roiler out of contact with the eccentric on the main-shaft which would be desirable when the trimmer is to be used for a considerable time. For facilitating the throwing of this roller out of contact the angular block is provided with a manipulating pin 93..

Supposing the parts of the device to be downward across the lower blade. Because of the angular relation between the cutting edges of the blades, the cutting action is very similar to that of a pair of scissors. About the time the feed-dog commences to move upwardly into engagement with the fabric but before it reaches the fabric the cutting action 1 is completed. The upper blade is preferably so adjusted in the header carrier that it does not complete its severing action before its actuating eccentric starts to move both blades in the direction of feed, thus severing the material with a draw out. By timing the blades to act in this manner the trimmer also has a slight feeding action. on the goods, thus compensating for the crowding forward of the material due to the scissors-like action of the blades and thus eliminating wrinkles in the product. Where the machine is used for basting purposes and the stitch length varies from one-eighth to seven thirty-seconds of an inch this compensating feed action of the blades is especially desirable.

By adjusting the upper blade farther away from the lower blade the draw-cut and compensating feed actions before mentioned may be increased. Such an adjustment is usually made to accommodate thick fabrics when increased draw-cut and compensating feed actions are more advantageous.

With certain limitations it is obvious that a trimmer mechanism such as disclosed can be operated to sever mate-rial at any time when the feeddog is out of contact with the goods and by adjusting the feed-eccentrics and the trimmer eccentric relatively a cutting action can be effected at any desired time. It is preferred however to delay this action until the feed-dog is about to riseand engage the fabric. For certain classes of work, should it be desirable, the cutting action might even be delayed until after the feed-dog has engaged the fabric owing to the fact that both blades of the trimming mechanism are given or may be given a movement in the direction of feed very similar to that of the feed-dog.

It is obvious that the size and shape of the upper blade may be varied to meet the demands of the work. lVhen it is desired to do applique work, for example, the upper blade may be in the shape of a piercer 132 (shown in Fig. 9) which is an old and well known form of blade. I

The foregoing description relates to the invention as embodied in a sewing machine with trimming blades located at one side of the needle. However, the trimmer withor ing machines.

\Vhere it is desirable'or necessary to throw the trimmer into and out of action at will an alternative form of fulcrum-plate shown at 141 in Fig. 6 may be used. This modified form of plate has a rearward extension 14-2 to which a treadle rod 143 is connected for conveniently swinging the fulcrum-plate against the resistance of a spring (not shown in'Fig. 6) which may be arranged as at 83 in the previously described form of the latch-lever. The sides ofthe latch-pin 176 are beveled as shown to correspond to the inclined sides of the teeth 174 between the recesses 172l73 in which thelatch-pin 176 may. rest when a piercing'blade is in either of its extreme positions. The teeth ll' l'have new and important function in that they enable the angle at which a pointed upper blade may emerge from the throat-plate being varied to suit the peculiar needs of the material being operated upon. This angle the stitching point to permit a covering thread being lald over the raw edges of the work as 1s done in neckfor convenience may be. termed the critical angle for piercing, Any suitable form of presser-foot having the necessary clearance for the piercer may be used; It will also be seen that as the trimmer mechanism is with drawn farther and. farther toward its ineffective position the length of the cut will be correspondingly diminished. e

It will also be distinctly understood that some of the advantages of the invention may be realized with a stationary lower blade. deference should therefore be made to the appended claims to determine the scope of the invention.

Having thus set forth the nature i vention, what I claim herein is:

of the 1. In a sewing machine, in combination with work feeding mechanism, trimming mechanism comprising a palr of actuated severing members, an eccentric, and means ope-rated by said eccentric for both relatively and bodily moving said members.

2. In a sewing machine, in combination,

work feeding mechanism, fabric severing mechanism comprising upper and lower blades, means for actuating said blades to sever fabric, and means for permitting said first mentioned means to automatically shift said blades from an ineffective to an effective fabric severing position.

3. In a sewing machine, in combination with work feeding mechanism, trimming mechanism comprising a pair of cooperating severing members and means for differentially moving said members including an eccentric strap and a rocking lever slidably connected together.

* 4; In a sewing machine,: in combination iao with work feeding mechanism, trimming mechanism compris ng a pair of severing members, means foractuating one of said members in a closed path and the other member back and forth in the general-d1- rection of the line of seam formation, and

means for shifting the effective cutting posi- 'with work feeding mechanism, trimming "mechanism comprising a pair of members relatively movable to effect a severing of material, actuating means therefor'including a shaft, one of said members being arranged for pivotal movement about said shaft as an axis to withdraw it from effective severing position, and means connecting the last mentioned member with the other member to effect its withdrawal likewise.

6; In a sewing IIlIClllllQ Hl combinat on with work feeding mechanism, trimming mechanism comprising a pair of cutting members,'one of which is capable of being shifted to effective or ineffective position, means for moving-said members relative to each other to sever fabric, and means for shifting said one of the members to one of said positions when the machine is rotated reversely.

7. In a sewing machine, in combination with work feeding -meehanism, trimming mechanism comprising upper and lower severing members, means for moving the upper member down across the loWer member to sever material, said'means including a support for the upper member surrounding the actuating shaft and carrying a friction element whereby said upper member may be moved to an ineffective position when the machine is reversed. a 1

8. In a sewing machine, trimming mecha nism, actuating means therefor, manually shiftable means connecting said trimmin mechanism and actuating means for throwing the former out of operative position, and means for holding the trimming mechanism in either operative or inoperative position.

9. In a sewing machine, in combination with work feeding mechanism, trimming mechanism comprising an upper movable member and a lower member cooperating therewith, means for imparting movements to said upper member in the direction of feed about a pivot spaced from but'parallel to the actuating shaft, said pivot being hinged upon said actuating shaft whereby the upper member may be moved to an effective or ineffective fabric severing position.

10. In a sewing machine, in combination with work feeding mechanism, trimming mechanismucomprising a pair of relatively movable severing members, means for moving said members relatively vertically,

means for moving said members horizon.- tally, said means being timed to move the member horizontally, before the relative vertical movement thereof has been completed whereby compensation is'provided for the crowding of material in a direction opposite to the feed due to the scissor-like action of the members. I

11. In asewing machine, in combination with work-feeding mechanism, a trimming mechanism comprising an upper movable blade and a lower blade 'cotiperating therewith, a shaft, means for actuating said blades from said shaft, means for supporting said blades including a fulcrum-pin arranged on the side of said shaft opposite the upper, movable blade, and means for shifting said fulcrum-pin so that the trimming mechanism is effective or ineffective.

12. In a sewing machine having stitchforming mechanism, in combination, a throat plate, workfeeding mechanism and trimming mechanism including upper and lower fabric-severing blades, a shaft, means for supporting said blades in cutting position above the shaft including a fulcrum-pin located substantially perpendicularly beneath the blades when in fabric-severing position, and means for actuating said blades from the shaft to sever fabric, said last-men- 'tioned means permitting the depression of both blades beneath the throat-plate.

13. In a sewing machine having stitchformin mechanism including a looper end- Wise movable in thegline of feed and actuating -mechanism therefor, .in .combination,

workfeeding mechanism and trimming mechanism. including upper and lower blades, movable in a. vertical plane parallel with the line of feed, means for actuating said blades including an eccentric-strap for imparting vertical movements to one of said blades relative to the other and for imparting horizontal movements to both of said blades, and means for automatically throwing said blades from an ineffective to an effective fabric-severing position.

14. In a sewing machine having a stitch forming mechanism,.in combination, a shaft, work feeding mechanism, and trimming mechanism'including a pair of cooperatively arranged fabric-severing blades, means for relatively actuating said blades to sever fabric, comprising an eccentric on the shaft, an eccentric-strap embracing said eccentric, a rock-lever, a sliding connection between said eccentric-strap and said rock-lever, and a fulcrum-pin for said rock-lever, said fulcrum-pin being adjustably hinged, upon said shaft whereby it may be variously located about the axis of the shaft. 7

I 15. In a sewing machine, a trimming .mechanismincluding a pair of cooperative fabric-severing elements, a rocking lever, a

together about the fulcrum-pin as an axis lating said, lever connected thereto interme-.

diate its ends, an u per blade supported by a part of said oscil ating mechanism whereby said upper and lower members are moved and the upper member is moved additionally in a direction transverse to the first-mentioned movement. v

16. In a sewing machine, a trimming mechanism including a pair of cooperating fabric-severing elements, a rocking lever, a blade secured at one end thereof, a fulcrumpin for supportingsaid lever at its other end, mechanism for oscillating said lever about said fulcrum-pin and connected thereto at a point intermediate its ends, a second blade held by a part of said actuating mechanism, said fulcrum-pin being arranged parallel with the main-shaft of the machine. v17. In a sewing machine, a trimming mechanism including apair of cooperating fabric-severing elements, a rocking lever, a blade secured at one end thereof, a fulcrumpin for supporting said lever at its other end, mechanism for oscillating said lever about said fulcrum-pin and connected thereto at a point intermediate its ends, a second blade, a head or carrier for holding said blade in cooperative relationship with said lower blade, a sleeve connected to said head and loosely supported by said part of the oscillating mechanism, and a spring for holding said upper blade against the lower blade.

18. In a sewing machine having stitchforming mechanism, in combination, workfeeding mechanism and trimming mechanism, including an upper movable blade having a piercing point, a lower blade having a movement in common therewith, and manually controlled automatic means for actuating said upper blade to pierce the lower of superimposed plies of fabric.

19. In a sewing machine having stitchforming mechanism, in combination, workfeeding mechanism and trimming mechanism, including an upper blade having a piercing point, a lower blade cooperating therewith, means for actuating said upper blade in a closed path to pierce and sever the lower of superimposed plies of fabric, and means for varying the inclination of the upperblade to cause the piercing point to enter the fabric at a preferred angle whereby material of different texture may be operated upon or the operation of the piercing point may be most saisfactorily adjusted for the same goods.

20. In a sewing machine having stitchforming mechanism and a throat-plate, in

combination, work-feeding mechanism and trimming mechanism including an upper blade having a piercing point, a lower blade cooperating therewith to sever fabric and located beneath the-throat-plate, said upper blade being mounted for movement through the throat-plate, means for imparting movement in a closed path to said upper blade, and means for varying the position of the upper blade so that the angle formed by the piercing point with the throat-plate as it emerges therefrom maybe suited to the material being'operated upon. a

21. The combination of a work-support, a shaft located below the work-support, a

rocking lever, a fulcrum member for said rocking lever, a pivotal support for said fulcrum member coaxial with said shaft, a

crank element on said shaft, a strap operatively connecting said crank element and said rocking lever, a pointed cutting blade carried by said strap, a ledger-blade cooperating with said pointed blade, and means for swingin said pivotal support about the axis of the shaft whereby the cutting blade may b thrown into operative position with its piercing point directed/upwardly to enter the work.

22. In a sewing machine having a worksupport, in combination, work feeding mechanism and fabric severing mechanisms, the

latter including a pair of cutting blades actuated and supported from' belowv the worksupport, and means for permitting said blades being automatically shifted from ineffective to effective fabric severing position without stopping the action of the machine. 23. In a trimmer, .mechanism, coacting blades, and means for closing said blades and simultaneously impartingwith the .closing movement to both blades a movement in the direction of feed.

24. In a trimmer mechanism, coacting blades having distinct trimming movements, means for imparting said movements, and means including said first means for moving said blades to an inoperative position 25. In a trimmer mechanism, coacting blades, means for actuating said blades, and means for bodily shifting the blades to vary the initial angle of engagement between said blades and the material to .be cut.

26. In a trimmer mechanism, coacting blades, means for moving one of said blades in a closed path, means for moving the other blade in an arc, and means for moving both blades to an inoperative position.

27. In a trimming mechanism, a shaft, an eccentric and strap carried thereby, a blade mounted on said strap, a second blade, and

a sliding connection between said strap and means from which said elements derive rela tive sliding movements. g

and means for 29. In a trimmer, a blade having a pivot, a coacting blade having a pivot spaced from the first pivot, means for connecting saidblades, means for shifting one of said pivots about the other pivot as a center, and actuating means for the trimmer.

80. In trimmer, coacting blades, means for simultaneously giving said bladesa rela tive cutting movement and a movement in unison therewith in the direction of feed, arying the initial angle of engagement of the blades with the material.

oi. In a trimmer, pivot-ally mounted blades, a connection between said blades,

means for shifting the pivot of one of said blades to actuate them, and means for shirt ing the pivot of the other blade to render them inoperative.

32. In a sewing machine, in combination With work-feeding mechanism, trimming mechanism comprising a pair of cutting members, one of which is capable of being shifted to effective or ineffective position,

means for moving one'of said members relative to the other to sever fabric, and means for shifting one of the members to one of said positions when the machine is rotated reversely.

33. In a sewing machine, in combination *ith Work-feeding mechanism, trimmingmechanism comprising a pair of relatively movable severing members, and means for at will bodily shifting the trimming mech anism including both severing members variable amounts from a position of maximum length oi cut to a position of entire ineffectiveness.

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

ALBERT H. DE VOE.

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