US2046945A - Trimmer mechanism for sewing machines - Google Patents

Description

July 7, 1936. E. M. HANF TR IMMER MECHANISM FOR SEWING MACHINES Filed May 11, 1935 gwuvwbo'b' Edward 1711101 Patented, July 7, 1936 PATENT oFFicE.

TRIMMER. MECHANISM" FOR SEWING MACHINE Edward. M. Hanf, Bridgeport, Chum, assignorto Thesin'ger Manufacturing Company, Eliza;- beth', J-., acorporatioirofNewJersey yApplicatioxi May 11, 193-5, Serial; m mas i '4 Claims. .(c1.112 127) Thisinvention relates to trimmer mechanism for sewing. machines. and more particularly to improvements in underedge trimmer mechanisms designed for trimming off the margin of the under -'5. of twoor HIOIQDHQSgOf material in the operation of uniting said plies by stitches.

It is the primary object of the present invention to provide'durable means for maintaining an effective shearing relationship between the movable and ledger-blades of a trimmer mechanism and more specifically in the trimmer mechanism disclosed in the U. S. patent to- J. C. Binge, No. 1,526,436, Feb. 17, 1925.

The invention consists in the improved knifebar guiding means hereinafter described and as set forth in the appended claims.

In the drawing, Fig. 1 is a front end elevation of the bracket-arm head and a portion of the cloth-plate of a sewing machine containing a preferred embodiment of the present invention. Fig. 2 represents a section of the bracket-arm head in a vertical plane adjacent to the trimmerbar. Fig. 3 represents a perspective view of the trimmer-bar guide-stud. Figs. 4 and 5 represent perspective views of the trimmer-bar guidebrackets.

The sewing machine, partly illustrated in the drawing and more fully described in said prior Patent No. 1,526,436, has a horizontally disposed bed-plate I supporting a throat-plate 2, suitably apertured to receive a feed-wheel 3 and recessed in its upper face to receive a ledger-blade 4. Adjacent to the ledger-blade 4, the throatplate is provided with a vertically inclined trimmer-knife aperture 5. overhanging the bedplate I is a bracket-arm head 6 in which is pivotally hung a swinging frame 1 providing bearings for a vertically reciprocatory needlebar 8 carrying at its lower end a needle 9. Journaled for vertical movement in suitable bearings provided in the bracket-arm head 6 is a presserbar ll) carrying at its lower end a roller-presser H yieldingly opposed to the feed-wheel 3.

Vertically slidable in the upper end of the presser-bar I is a spring-pressed trimmer-lifter rod 12 engaging an angular plate l3 suitably secured upon the upper end of a trimmer-bar I4. The trimmer-bar I4 is journaled within the head 6 for endwise reciprocatory and laterally vibratory movements resulting in a vertically inclined operative path of said bar. For this purpose, one side edge of the trimmer-bar, adjacent to its upper end, is provided with a rounded proturberance I slidably engaging a wall l6 of a trimmerbar guiding recess I! in the bracket-arm head 6 Opposedto the recess-wall l6 is a convexly curved. wall |8- engaged by the-slightly concave edge l9- of the trimmer-bar opposite to the protuberance I 5, thereby providing a sliding fulcrum for the trimmer-bar whichtis confined by 5 the walls of the recess H to movements in a vertical plane transverse to a vertical plane containing the line of feed of the work.

Adjacent to its lower end, the trimmer-bar I4 is provided with substantially parallel guides 20, 10 2| constituted by the edges of said bar which are opposed to each other transversely of the line of seam formation, said guides being inclined to the length of the trimmer-bar. The guide 20 slidably engages a guideway 22 comprising the 15 diametral face of a substantially semi-circular guide-stud head 23 having a bearing trunnion 24. The arcuate portion of the segmental head 23 of the guide-stud and the trunnion 24 thereof are journaled in a shouldered bearing-aperture 20 25 provided in one member 26 of an angular supporting-bracket, the other member 27 of said bracket being secured by screws 28 upon the head 6 of the machine bracket-arm. The bracketmember 26 is partly cut away to provide a trim- 25 mer-bar confining face 29 terminating in a vertically inclined shoulder 30 intersecting the guide-stud bearing aperture 25. The guideway face 22 of the guide-stud projects beyond the bracket-shoulder 33, thereby constituting a rock- 30 ing bearing for the trimmer-bar guide 20 independently of said shoulder.

Directly opposite to the guideway 22 of the guide-stud is an adjustable screw 3| endwise engaging the trimmer-bar guide 2|, said screw 35 3| being adjustably threaded into a bracket 32 secured by screws 33'upon the head 6 of the machine bracket-arm. It will be understood that by reason of the described guiding means for the trimmer-bar M, the lower end of the 40 trimmer-bar will be vibrated laterally upon endwise reciprocation of said trimmer-bar. The pivotal guide-stud 23, 24 provides for maintaining the entire length of the guideway 22 of said guide-stud in engagement with the guide 20 of the endwise reciprocatory and laterally vibratory trimmer-bar l4, thereby insuring accurate guiding of said trimmer-bar.

Adjustably secured by screws 34 to the lower 50 end of the trimmer-bar I4 is a knife-holder 35 to which the vertically inclined trimmer-knife 36 is suitably secured.

The trimmer-knife has the usual guide-finger 31 adapted to enter the throat-plate aperture 5, 55

and has a cutting edge 38 which coacts with the ledger-blade 4 to sever the work.

Endwise reciprocatory movements are imparted to the trimmer-bar M by a vibratory arm 39, releasably connected to said bar by a stud 40 adapted to enter a notch 4| in a side edge of the trimmer-bar, said arm 39 being carried by a rock-shaft 42 which may be actuated in any usual or suitable manner.

Having thus set forth the nature of the invention, What I claim herein is:

1. Trimmer mechanism for sewing machines comprising, a trimmer-knife carrying bar provided with a guide inclined to the length of said bar, actuating mechanism for endwise reciprocating said bar, a rocking guideway slidably engaged by said guide, and means effective to maintain said guide and guideway in sliding engagement.

2. Trimmer mechanism for sewing machines comprising, a trimmer-knife carrying bar provided with a guide, actuating mechanism for endwise reciprocating said bar, a rocking guidestud slidably engaged by said guide, and means adjustably opposed to said guide-stud for maintaining said guide and guide-stud in sliding engagement.

3. Trimmer mechanism for sewing machines comprising, a, trimmer-knife carrying bar provided with a guide inclined to the length of said bar, actuating mechanism for endwise reciprocating said bar, a rocking guide-stud having a trunnion and a head providing a guideway slidably engaged by said trimmer-bar guide, a journal-bearing for the trunnion of said guide-stud, and means effective to maintain said guide and guideway in sliding engagement.

4. Trimmer mechanism for sewing machines comprising, a trimmer-knife carrying bar provided with substantially parallel guides, actuating mechanism for reciprocating said bar, a rocking guide-stud having a trunnion and a segmental head providing a guideway slidably engaged by one of said trimmer-bar guides, a journal-bearing for the head and trunnion of said guide-stud, and an adjustable screw disposed directly opposite to said guideway and endwise engaging the other of the trimmer-bar guides.

EDWARD M. HANF.

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