US247285A - Wax-thread sewing-machine - Google Patents

Description

Ei WOODWARD. WAX THREAD SEWING MACHINE.V

Patented Sept. 20, 1881'.

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UNTTED STATES PATENT OFFICE. A'

ERASTUS WOODVABD, OF BOSTON, ASSIGNOR TO GEORGE W. OOPELAND,

TRUSTEE, OF MALDEN, MASSACHUSETTS.

WAX-THREAD SEWING-MACHINE.

SPECIFICATION forming part of Letters Patent No. 247,285, d

ated September 20, 1881.

Application filed September 8, 1880. (Model.)

.To all whom it may concern Be it known that I, ERAsTUs WooDWAnD, of Boston, in the county of Suffolk and Commonwealth of Massachusetts, have invented an Improvement in Wax Thread Sewing -Machines, ot which the following is a specification.

This invention has for its object the following-described improvements i n wax-th read sew- Io ing-machines. lt is an improvement upon the sewingmachine shown and described in Letters Patent, Reissue No. 6,535, granted Gordon McKay and RobertH. Mathies,assignors, dated July 6,1875. It embraces, first, means where.-

by the length of stroke of the needle-bar is determined by the position of the presser-foot; second, means whereby the cast-off bar is adjusted automatically by the needle-bar and presser-foot. j Referenceis madeto the accompanying drawings, forming a part of this specification, in explaining the nature of the invention, in

whichl Figure l is a front elevation of my improvement. Fig. 2 is a view part in side elevation and part in section. Fig. 3 is a view partly in plan and part-ly in section upon the line yy of Fig. l. Fig. 4 is a cross-section on the line zz of Fig. 2. Fig. 5 represents certain details of construction. Fig. 6 is a view representing a friction-block attached to the needle-bar, and adapted to be placed in position thereon, according to the thickness of the work, by the presser-foot, in a manner substantially as hereinafter set forth. l y

In wax-thread sewing-machines having a stationary rest or bed for the work, organized for sewing material of varyin g thicknesses with a chain-stitch, it is necessary to vary the length of thread used in making a stitch as the sewing progresses from thin to thick work, and vice versa, and this variation must be eli'ected by the needle. Therefore, as more thread :is used in sewing thick work, the needle-bar must have a greater throw than in sewing thin work. The needle must always descend to the same base-line, and consequently the variation in the length of stroke of the'needle-bar must be from that line upward. It is also desirable to connect the cast-0E with the needle-bar and presser-foot, so that the movements given the cast-off may be automatically determined by them and be obtained by simple mechanism.

A represents the cam for operating the needle-bar. -The lever B connects the cam with the link b, which is pivoted at its lower end by the stud b to the block b2, through which the needle-bar passes, and to whichV it is fastened by means of the set-screw b3. The said lever -B is pivoted at bl to a sliding sleeve, b5, which is adapted to have a limited movement upon the rod b against the stress of spring 117, as hereinafter explained. The stop bs, fastened Yto said rod bythe set-screw b9, serves to adjust said sleeve, and consequently the fulcrum of thelever, in its proper position. f The presserfoot bar C is provided with the projecting arm c, which is arranged to slide on the rod b", against the pressure of the spring bl, before named, and in addition is provided with a bracket or arm, c', having a recess, c2, which receives a stud, c3, fastened to a friction-block, c, through whichthe needle and cast-off bars c c2 pass. The presser-foot-bar has also an arm, c5, which projects over the 'end of the 75 lever B. t

The operation of this part of my mechanism, lby which a varying stroke is provided the needle-bar governed by the presser-foot, is as follows :l The cam A is cut to provide the needlebar, by its connecting mechanism,with a throw that will be sufficient for drawing the thread necessary for making a stitch in the thickest material. The pivot bfin this instance will-be stationary. For sewing work of less thickness the needle-bar is not provided with so great a stroke, and this is accomplished by causing the arm c5 to act as a stop, against which the end of the lever B comes in contact, thereby causing the fulcrum b4 of the lever B to yield downwardly. Ot' course, the higher the arm or stop c5 the less the downward movement of the fulcrum and the greater-the throw of the needle-bar. The presser-foot bar is operated by a cam or any other suitable mechanism, and as it lifts from the work it com presses the spring 127, and also adjusts the arm or stop c5 to a position to which the end 'of the lever B may arise before the fulcrum b4 takes up the lost motion.

The block c4 is provided with a friction-plug, c6, which is forced inwardly against the cast- IOO off bar by means of the spring c, fastened to the block. The needle-bar moves freely in the block. This construction provides for an upward movementJ of the cast-off bar, for reasons hereinafter explained.

Below the friction-block c4 there is arranged another friction-block, D, which is similar in construction to the one first described 5 but the friction-plu g, instead ot bearin g upon thecast- 0E bar, bears upon the needle-bar, and the cast-off bar is arranged to move freely therein.

Below the last-named friction-block there are two blocks, d d', which are fastened by setscrews to the cast-off bar.

The operation of the needle-bar, cast-oft' bar, and presserfoot to accomplish the proper movements of the cast-otrn in relation to those of the needle-bar or needle is as follows: The needle-bar is lifted a short distance, equal in extent to the thickness of the workand the extent of the needle below the surface-plate to the barb. The cast-off bar is then started and'moved upwardly at the same rate of speed with the needle-bar until the highest point of the needle-bar stroke is reached. The needlebar is then moved downwardly sufficiently to uncover the barb, and the cast-oft bar is then moved simultaneously with the needle-bar until it reaches the surface of the work.

As it is essential that the needle-bar have a varying extent of throw, and as the presserfoot,while it lifts a uniform distance from the surface of the work, yet by the variations in the thickness of the work has an irregular throw from the work-plate of the machine, it is necessary to provide a compensating mechanism whereby the'cast-oii bar may continue to have the same relative movements with the needle-bar while the variations in the length of throw are transpiring. In order to understand this portion of my mechanism it is necessary to bear in mind, rst, that the cast-off bar is lifted by the needle-bar by means of the block' b2, fastened to the needle-bar, and the block d', fastened to the cast-olic bar, the said block d being so placed as to allow the cast- 0E to descend to the lowest position in which it can be used; second, that the friction-block c, which is positively moved by the presserfoot-operating mechanism, is so attached to the cast-off bar that while it allows the same to be moved therein when positively actuated, it also, by means of suitable frictional mechanism, operates at certain times to hold the same, so that upon the upward movement of the presser-foot bar the cast-oif bar is moved upward; and, third, that thefriction-block D, attached to the needle-bar, and the block d, attached to the cast-oft' bar, serve to lower the cast-od' bar.

The position of the friction-block D upon the needle-bar is changed automatically durfl ing the upward stroke of the needle-bar and cast-off bar by contact with the upper block, c4, (which is held stationary while the needle-bar continues to rise,) and thereby, upon the downward movement of the needle-bar, by contact with the block d, moves the cast-oif to the surface ofthe work. As it is necessary, however, that the needle should commence to descend before the cast-off, that the barb of the needle may be uncovered, the cast-oft bar is retained by the friction-block c4 in its highest position, while the needle-bar is moved downwardly a short distance. The cast-off bar is then caused to descend simultaneously with the needle-bar by the regulating block D, which, moving down with the needle-bar, comes in contact with the block d. This regulating-block is always placed in position by the block c4 upon its upward movement, so that the space between it and the block d determines the extent of downward movement of the needle-bar before the cast-olf bar is operated. The friction block c4 also holds the cast-od in position upon the work until it is positively lifted upon the upward movement of the needle-bar by the blocks b2 and d. The friction-plugin the block D must bear with greater force or stress against the needle-bar than the friction-plug in the block c4 bears against the cast-oi bar, in order that the said block D in its downward movement may draw the cast-od bar with it and not slip on the needle-bar.

It will be noticed that the lost motion or compensation, whereby the movementl of the cast-off bar is not increased during the increased movement of the needle-bar, is obtained or e'ected by the regulating block D, which is adjusted by contact with the block c* to a given position upon the needle-'bar in relation to the block d at every upwardmovement, and which also comes to rest when the cast-off reaches the work,while the needle-bar continues to descend, thereby taking up the difference of movement between the twobars,

IOO

both at the end of the downward and upward stroke thereof.

To guard against the yielding or spring of 'any part of the needle-drivingl mechanism while the needle is in the work, I provide the lever B with a curved arm, E,the end of which rides upon the stationary block c from the time when the needle is about to enter the material on its downward stroke until it has cleared it upon its upward, thereby holding the fulcrum b4 in a fixed position during this part of the movement of the needle-bar. The tripping of this locking-arm upon the further upward movement of the needle-bar leaves the fulcrum b4 and sliding sleeve b5 free to be moved downwardly against the stress of the spring; yet such downward movement will not take place to any extent until the outer end of the lever-bar comes in contact with the stop c5.

It will be observed that the mechanism for effecting the variations vin the stroke of the needle-bar is very simple, and that upon the contact of the outer end ofthe lever with the lstop c5 the fulcrum of the lever is changed from the pivot b4 to its outer end, and the pivot b4 and the supporting sleeve yield downwardlyg also, that the position ofthe stop c5 is automatically fixed by the presser-foot; also, that the cast-ofi' is actuated by the needle-bar IIO and presser-foot bar through the medium of intermediate compensating frictional mechanism.

F is the needle; G, the cast oft', H, the presser-foot.

The rod b6 may be adjusted vertically by means of suitable adj usting-screws, thereby adjusting the stop 118.

The cam for operating the mechanism reciprocating the needle is so shaped that the needle-bar starts slowly and has a gradually accelerating movement, in order that the strain upon the thread may not be severe at the commencement of the upward movement of the needle.

It will be noticed that the spring Z7 not only serves to automatically return the sliding sleeve b5 to its original position on each throw of the needle-bar, but that it also acts to hold down the presser-bar; also, that the higher the presser-foot is lifted thevless the sliding sleeve is depressed, and therefore the strain upon the spring during all depressionsis very nearly uniform.

The operation of my mechanism has been eX- plained coincidently with its description.

The presser-foot may be held down by an iudependent spring in lieu of the spring 117, if desired.

Having thus fully described my invention, I claim and desire to secure by Letters Patent of the United States- 1. In a wax-thread sewing-machine, the combination of the cam A, the lever B,the needlebar C', the devices connecting the end ot' the lever with the needle-bar, with the sliding lever supporting sleeve b5, and the stop e5, adapted to be placed in position by the material sewed, substantially as and for the. purposes described.

2. In a wax thread sewingmachine, as a means ot' varying the stroke of the needle-bar, the lever B, adapted to be operated by a cam, and mechanism, substantially as specied, placed-in position by the work for transferring the fulcrum of the lever from or near its center to its outer end, all substantially as and for the purposes described.

3. In awax-thread sewing-machine, the combination of a lever, B, for reciprocating the needle-bar, pivoted at b4 to the sliding sleeve b5, the said sliding sleeve b5, the spring b", and

4the stop c5, all substantially as and for the purmachine, of a lever, B, for operating the needle-bar, with a yielding sleeve, b5, to which the lever is pivoted, andrmeans for reciprocating the lever, all substantially as described.

6. In a wax-thread sewing-machine, the combination of the presser-foot bar, adapted to be lifted a uniform distance from the level of the work, and provided with the stop c5, and arm C, with the lever B, the sliding sleeve b5, spring bl, and cam A, all adapted to operate substantially as set forth.

7. The block D, frictionally attached to the needle bar, in combination with the presserfoot and connecting mechanism, whereby the block is placed in position upon the needle-bar according to the thickness of the work, all substantially as and for the purposes speciied.

8. The combination, in a wax-thread sewingmachine, of a needle-bar and cast-od' bar, and block D, frictionally attached to the needlebar, and placed in position thereon by the presser-foot, and the block el, rigidly fastened to the presser-foot bar, all adapted to automatically regulate the downward motion of the cast-off bar, all substantially as and for the purposes described.

9. In a wax-thread sewing-machine, the block n b?, attached to the needlebar, the block d', fastened to the cast-off bar, the irictional block c4, positively actuated by the presser-foot and frictionally attached to the castoft' bar, the friction-block D, and the block d, attached to the cast-oft' bar, all adapted to operate to automatically vary the throw of the cast-off bar, substantially as described.

ERASTUS WOODWARD.

Witnesses:

F. F. RAYMOND, 2d, A. J. GETTING-ER.

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