US2108138A - Sewing and trimming machine - Google Patents

Description

Feb. 15, 1938. R. s. PAINTER SEWING AND TRIMMING MACHINE 4 Sheets-Sheet 1 Filed Feb. 27, 1936 Feb. 215, 1938. R. s. PAINTER I SEWING AND TRIMMING MACHINE Fil ed Feb. 27, 1956 4 Sheets-Sheet 2 #0 w m M @mu w a 2 Z a T; J m w .v w w b 0U E i i PQ pm V mvbw P 2 a, W y 2 a F 2% H 2 Feb E5, 193%. I R. s. PAINTER SEWING AND TRIMMING MACHINE Filed Feb; 27, 1936 4 Sheets-Sheet 5 Patented Feb. 15, 1938 UNITED STATES PATENT OFFICE SEWING AND TRIM'M'ING MACHINE Application February 27, 1936, Serial No. 66,012

14 Claims.

This invention relates to improvements in trimmer mechanisms and more particularly to trimmer mechanisms of sewing machines, the invention having for its primary object to provide a sewing machine with an eificient and commercially practical trimmer mechanism adapted to effect the production of smoothly trimmed and sharply curved edges in work, conjointly with the stitching operation.

A more specific object of the present invention is to improve the quality of the product obtained by the use of sewing machines fitted for simultaneously stitching the edges and undertrimming the linings of shoes, etc.

Another object of this invention is to provide a work-severing trimming machine having a work-feeding mechanism with means for controlling the relative speeds of operation of the work-feeding and work-severing mechanisms.

With the above and other objects in view, as will hereinafter appear, the invention comprises the devices, combinations and arrangements of parts hereinafter described in connection with the accompanying drawings, in which:

Fig. 1 is a rear side elevation, partly in section, of a sewing machine provided with the improved trimmer-actuating mechanism. Fig. 2 is a front end elevation, partly in section, showing the bracket-arm and work-supporting post of the sewing machine. Fig. 3 represents a top plan view of the sewing machine, with the bracketarm shown in longitudinal section. Fig. 4 is a detail view in side elevation of a portion of the trimmer-knife actuator bar and its driving stud. Fig. 5 represents a rear side elevation of the sewing machine mounted upon a supporting table provided at the under side thereof with a treadlecontrolled electric-transmitter for driving the sewing machine, certain parts of the sewing machine being omitted.

Referring to the drawings, the present invention is illustrated as embodied in. the commercially well known Singer No. 51W56 sewing and underedge-trimming machine. This sewing machine has a frame comprising a, bed-plate I, from one end of which rises a work-supporting post 2. Upon the opposite end of the bed-plate I is the supporting standard 3 of a bracket-arm 4 which terminates at its free end in a head 5 overhanging the work-supporting post 2.

Journaled in the bracket-arm 4 is a horizontally disposed main actuating shaft 6 carrying at one end a combined belt-pulley and balancewheel I. At its opposite end, the main shaft 6 is provided with a crank-disk 8 operatively connected by the usual link 9 with a needle-bar H! carrying at its lower end a needle I i, said needlebar i0 being journaled for vertical reciprocation in suitable bearings provided in the bracket-arm head 5. The needle H cooperates, in the formation of lock-stitches, with the usual loop-taker I2 disposed within the frame-post 2.

The work is intermittently advanced by a dropfeed mechanism including a feed-bar l3 disposed vertically within the post 2 and carrying at its 10 upper end a feed-dog M. The feed-dog 14 operates through a suitably slotted throat-plate l5 secured upon the post 2 and is opposed in its rising movement by a presser-roller it closely adjacent to and at one side of the path of needle- 1.5 reciprocation. The presser-roller I6 is carried by the lower end of the usual spring-depressed presser-bar ll journaled for vertical movements in suitable bearings provided in the bracket-arm head Depending from the under side of the bracketarm 4 is a frame-boss l8 provided with a flattened lower face affording a seat for a trimmer-bracket l9 fixedly secured to said boss by screws 20. Journaled in suitable bearings provided upon the trimmer-bracket I9 for endwise reciprocation in a vertically inclined path is a knife-bar 2| carrying, at its lower end, a knife-holder 22 to which a Work-severing element in the form of a straight-edge trimmer-knife 23 is secured by screws 24. While the cutting edge of the knife is straight, it is preferably inclined downwardly in the direction of feed, as illustrated in dotted lines in Fig. 2 of the drawings. The trimmerknife 23 has a path of movement to sever the Work substantially parallel to the line of seam formation and at the side of the needle I l opposite to the presser-roller Hi. The movement of the trimmer-knife in a vertically inclined path transverse to the plane of the work results in the production of undercut trimmed edges and, accordingly, in the trimming of shoe linings the trimmed edge of the lining is concealed by the beveled edge of the shoe-upper, as is well understood in the art.

As heretofore constructed, the underedge cutting trimmer-knife has usually been actuated from the main shaft of the sewing machine to reciprocate once for each needle reciprocation. When stitching and trimming in sharp curves, occurring particularly in shoe production, the work is not only advanced by the feeding mechanism of the machine but is also sharply turned by the operator between successive reciprocations f t e trimmer-knife, according to the desired Cal work-edge outline. As a consequence, successive straight cuts made by the trimmer-knife intersect each other at an angle and the trimmed edge of the work presents an objectionable appearance. It has been heretofore proposed to overcome this difficulty by reciprocating the trimmer-knife twice for each needle-reciprocation, by the provision of suitable actuating connections with the main shaft of the machine, but this proposal has proven unsatisfactory for several reasons and particularly because of the lack of durability of the trimmer mechanism when operated at twice the frequency of the needle reciprocations at the higher speeds of operation of the sewing machine. The present invention obviates the diiiiculties inherent in the prior known arrangements in a simple and novel manner,

Suitably secured upon the knife-bar 21 is a collar 25 pivot-ally connected by a link 28 to an arm 2? of a bracket rigidly carried by the lower end of an actuator bar 28. The actuator bar 23 is confined to vertical reciprocation in suitable guide-slots 29 provided in the bracket-arm head 5, said bar 28 having in its outer edge a notch 36 adapted to receive a coupling-pin 3!. The coupling-pin 3! is carried by the free end of a crank-arm extending horizontally forward from one end of a rock-shaft 33 disposed substantially parallel to the main shaft 5, said rockshaft 33 being journaled for rocking and endwise movements in bearing-lugs 3 t upon the machine bracket-arm, at the rearward side thereof.

At its end opposite to the crank-arm 32, the rock-shaft 33 has a circumferential groove 35 embraced by a suitably notched car 36 upon one arm 31' of angular hand-lever 3?, 38. The hand-lever 3'1, 38 is pivotally mounted upon a horizontally disposed fulcrum-screw 39 extending transversely of the main shaft 6 and threaded into a boss lil upon the machine bracket-arm G. The arm 3? of the hand-lever depends below the bracket-arm 4 so as to be conveniently accessible from the front side of the machine, while the arm 38 of said lever is acted upon by a spring 4! to yieldingly shift the rock-shaft 33 in a direction to effect driving engagement by the coupling pin 3i with the actuator bar 28. A coil-spring 52 has its opposite ends connected to the bracket-arm 3 and to the knife-bar 2i to retract said knife-bar and thereby to raise the actuator-bar 28 into inoperative positions of said bars, when the handlever 3'5, 33 is operated to disconnect the coupling-pin 3i from the actuator-bar 28.

Pivctally mounted upon the trimmer-bracket i9 is a hand-lever as which is yieldingly held in inoperative position by a spring M. The upper end of this lever 53 has a lateral extension adapted, upon operation of said lever, to engage the upper end of the knife-bar 2i and to depress said knife-bar against the action of the spring 42. Being connected to the knife-bar M, the actuator-bar 23 is likewise depressed by operation of the hand-lever 43, until the notch 39 of the bar 28 is in alinement with the coupling-pin 3|, whereupon said coupling-pin enters the notch 39 under the influence of the spring 4|. It will, therefore, be understood that the trimmer-knife carrying bar I?! may be connected to and disconnected from the rock-shaft 33 at the will of the 4! carried by the rotor-shaft 4-8 of an electricmotor 49. The eccentric 41 is elongated to provide for the requisite sliding movement of the fork of the rock-arm 25 upon said eccentric when the rock-shaft 33 is shifted endwise to disconnect the coupling pin (it from the actuatorbar 28.

The electric-motor 48 is disposed so that its rotor-shaft is substantially parallel to and preferably at substantially the same level as the main shaft 5 of the sewing machine, said electricmotor being mounted upon a suitable bracket 59 secured by screws 5!. upon the rearward side of the machine bracket-arm l. The electric-motor has the usual current-controlling switch 52 and derives its power from suitable source, through current leads 53, so that the electricmotor may be operated independently of the operation of the sewing machine. A guard-bracket 54 houses the eccentric 4i and the forked end of the rock-arm lli, said guard-bracket having a supporting shank 55 secured by screws, as 5'5, upon the flattened upper face of the bearing-lug 3 which is adjacent to the rock-arm 46.

The sewing machine is preferably mounted upon a supporting table at the under side of which is disposed sewing machine driving means of any usual or suitable character. As illustrated in Fig. 5 of the drawings, this sewing machine driving means may comprise an electric-transmitter having a supporting frame 5'! suitably secured to the under side of the machine-supporting table 58. Carried by said frame 51 is an electric motor 59 having a rotor-shaft 60 upon which is secured a driving clutch-member 6| for rotation therewith. Adapted to frictionally engage the driving clutch member 6| is a driven clutch-member 52 which is peripherally grooved to form a belt-pulley connected by a belt 63 with the pulley i of the sewing machine. The driven clutch-member 62 may be shifted endwise of the rotor-shaft 69, into frictional engagement with the driving clutch-member 6!, by a lever 64 pivotally mounted upon an arm 65 extending from the transmitter-frame 5?. The lever 64 is connected by an adjustable rod 66 to a suitable treadle 81. By operation of the treadle 61, the lever G l may be actuated against the action of a spring 68 to bring the clutch-member 62 into frictional engagement with the clutch-member 6!, thereby to drive the sewing machine. speed of operation of the sewing machine may, of course, be varied by permitting slippage between said clutch-members. It is to be understood, however, that the present invention is not limited to the specific form of sewing machine driving means described, as any other suitable speed-controlling power transmitting device may be employed.

From the foregoing description, it will be understood that when the electric motor 19 is in operation, the rock-shaft 3;; derives rocking movements from the eccentric ll carried by the rotor-shaft d8 of the electric-motor. Upon operation of the hand-lever 5-3, the actuator-bar 28 is coupled to the crank-a m of said rock-shaft, thereby transmitting reciprocatory movements to the knife-bar 2i which may, at will, be disconnected from its actuating mechanism by manipulation of the hand-lever 3?, 38.

The rotor-shaft d8 of the electric-motor 19 rotates at a substantially constant speed, preferably at least equal to the maximum speed of rotation of the main shaft 6 of the sewing machine. Therefore, when the sewing machine is operated at maximum speed and the motor 59 is running,

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the trimmer-knife 23 reciprocates once for each needle reciprocation. However, it is only in substantially straight line stitching that the sewing machine is operated at maximum speed. As the work is not sharply turned during substantially straight stitching operations, the successive straight cuts performed by the trimmer-knife 23 are in alinement or so nearly in alinement that the trimmed edge of the work presents a smooth appearance.

On the other hand, the stitching of sharp curves is necessarily performed at slow speeds of operation of the sewing machine and, at such slower speeds, the trimmer-knife of the present invention continues to operate at the same speed as before. For example, if the trimmer-knife performs 2800 reciprocaticns per minute and the sewing machine is operated at a speed of 400 stitches per minute, the trimmer-knife will have seven work-severing strokes for each needle reciprocation. Consequently, when the work is sharply turned by the operator at the slower speeds of operation of the sewing machine, the intersections of successive cuts performed by the trimmer-knife approach each other so closely that smooth trimming is maintained. The present improvement therefore provides means for actuating the stitch-forming and trimming mechanisms at speeds having a ratio variable at will during the operation of the machine.

Sewing machines of the present type are often used merely for stitching operations and, for this purpose, it has heretofore been the usual practice to throw the trimmer-knife out of operation by means of the hand-lever 3'5, 38, leaving in operation the por ion of the trimmer mechanism includ ng the actuating eccentric and the fork embraced thereby. While the present arrangement includes this trimmer throw-out expedient, it need only be used when changing frequently from trimming to non-trimming operations. For any extended periods of operation of the sewing machine during which the trimming mechanism is not used, the operation of the electric-motor 49 may be discontinued, thereby minimizing wear of the eccentric t! and the fork of the rock-arm 46 embracing said eccentric.

If the sewing machine needle is omitted, the machine is adapted for trimming purposes alone. In this case, the speed of effective action of the feeding mechanism of the machine may likewise be varied at will relative to the frequency of reciprocation of the trimmer-knife, to provide for smoothly severing sharply curved work by means of a machine adapted to trim straight runs at high speed.

As illustrated in the accompanying drawings, the trimmer mechanism assembly includes the usual edge-guide and adjusting devices, which are, however, not herein referred to in detail, as a description thereof is considered unessential to an understanding of the present invention.

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

1. The combination with a sewing machine having a reciprocatory needle and needle-reciprocating mechanism, of a trimmer mechanism including a reciprocatory knife having effective worksevering movements adjacent said needle, and means operable independently of said needle-reciprocating mechanism for reciprocating said knife.

2. The combination with a sewing machine having stitch-forming mechanism including a rotary needle-reciprocating shaft and a needle reciprocated from said shaft, of a trimmer mechanism comprising a reciprocatory trimmer-element having effective work-severing movements adjacent said needle, a rotary actuating shaft disposed substantially parallel to and rotatable independently of said needle-reciprocating shaft, and operative connections with said actuating shaft for reciprocating said trimmer-element.

3. The combination with a sewing machine having a work-support, stitch-forming mechanism including a reciprocatory needle and work-feeding mechanism, of a trimmer mechanism including a trimmer-element having Work-severing movements adjacent said needle in a path inclined vertically to said work-support, and means operable independently of said stitch-forming and Work-feeding mechanism for reciprocating said trimmer-element.

4. In a sewing machine, the combination with simultaneously operable stitch-forming and Work-trimming mechanisms, of means for actuating said mechanisms at relative speeds having ratio variable at will during the operation of said machine, and means operable at will during the operation of the machine for interrupting the effective action of said work-trimming mechanism.

5. The combination with a sewing machine having a reciprocatory needle and needle-reciprocating mechanism, of a trimmer mechanism including a trimmer-element having effective work-severing movements adjacent said needle, means operable independently of said needle-reciprocating mechanism for actuating said trimmer mechanism, and means operable at will during the operation of the machine for substantially instantaneously interrupting the effective action of said trimmer mechanism.

6. In a sewing machine, the combination with simultaneously operable stitch-forming and work-trimming mechanisms, of means for actuating said mechanisms at relative speeds having a ratio variable at will during the operation of said machine, and means operable at will during the operation of the machine for throwing said work-trimming mechanism out of and into effective action.

7. The combination with a sewing machine having a reciprocatory needle and needle-reciprocating mechanism, of a trimmer mechanism including a reciprocatory knife having effective work-severing movements adjacent said needle, an electric motor operable independently of said needle-reciprocating mechanism, and operative connections with said electric motor for reciprocating said knife.

8. The combination with a sewing machine having a needle-reciprocating mechanism, of a reciprocatory trimmer-element, an electric m0- tor having a rotor-shaft operable independently of said needle-reciprocating mechanism, an eccentric carried by said rotor-shaft, and actuating connections for reciprocating said trimmer-element from said eccentric.

9. The combination with a sewing machine having a frame and a needle-reciprocating mechanism mounted upon said frame, of a reciprocatory trimmer-knife carrier mounted upon said frame, an electric motor mounted upon said frame and operable independently of said needlereciprocating mechanism, and operative connections with said electric motor for reciprocating said trimmer-knife.

10. The combination with a sewing machine having stitch-forming mechanism including a rotary needle-reciprocating shaft and a needle reciprocated from said shaft, of a trimmer mechanism comprising a reciprocatory trimmer-element having effective work-severing movements adjacent said needle, an electric motor having a rotor shaft disposed substantially parallel to and operable independently of said needle-reciprocating shaft, and means for reciprocating said element from said rotor-shaft.

11. The combination with a sewing machine having a reciprocatory needle and needle-reciprocating mechanism, of a trimmer mechanism including a trimmer-element having effective work-severing movements adjacent said needle, an electric motor operable independently of said needle-reciprocating mechanism, operative connections with said electric motor for actuating said trimmer mechanism, and means operable at will during the operation of said electric motor for substantially instantaneously interrupting the effective action of said operative connections.

12. The combination with a sewing machine having a frame including a work-support and a bracket-arm overhanging said work-support, a rotary needle-reciprocating shaft journaled in said bracket-arm, a vertically reciprocatory needle actuated from said shaft, and work-feeding mechanism, of a trimmer mechanism supported by said bracket-arm and comprising a reciprocatory trimmer-element having a work-severing path of movement adjacent to and inclined vertically to the path of needle reciprocation, an electric motor operable independently of and having a rotor-shaft disposed substantially parallel to said needle-reciprocating shaft, a rockshaft, means for imparting rocking movements to said rock-shaft from said rotor-shaft, and means connected to said rock-shaft and disconnect-ible therefrom at will during the operation of the machine for reciprocating said trimmerelement.

13. In a sewing machine, in combination, a reciprocatory needle and a reciprocatory worksevering trimmer-element adapted to be operated at a variable ratio of reciprocation-frequencies, means for reciprocating said needle, means for reciprocating said trimmer-element, and means for varying said ratio comprising controlling means for operating said sewing machine at difierent speeds.

14. The combination with a sewing machine having a reciprocatory needle, of a trimming mechanism including a reciprocatory work-severing element, variable-speed driving means for controlling the frequency of reciprocation of said needle, and substantially constant-speed driving means for reciprocating said element.

ROY STANLEY PAINTER.

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