US3789784A

US3789784A - Sewing machine

Info

Publication number: US3789784A
Application number: US00266526A
Authority: US
Inventors: S Hanyu; N Kasuga
Original assignee: Individual
Current assignee: Individual
Priority date: 1971-06-22
Filing date: 1972-06-22
Publication date: 1974-02-05
Anticipated expiration: 1991-02-05
Also published as: GB1361515A; JPS548148B1; AU461073B2; AU4373472A; DE2230661A1; CA963732A

Abstract

A thread take-up lever is reciprocable in vertical direction and receives thread from a thread tensioning device. Intermediate the take-up lever and the tensioning device the thread is supplied to a thread guide which is displaceable in parallelism with the movement of the take-up lever between an upper and a lower position. A dial is movable to at least two positions and is connected with the thread guide by linkage means so that the thread guide moves between its upper and lower positions in dependence upon the movement of the dial to the respective positions of the latter. Depending upon whether the thread guide is in its upper or lower position the amount of thread supplied to the take-up lever is varied, that is it is either increased or decreased.

Description

I Umted States Patent [191 [111 3,789,784 Hanyu et al. Feb. 5, 1974 SEWING MACHINE 2.997,0|0 8/1961 Hughes 112/254 [76] Inventors q l U Primary Examiner-George H. Krizmanich igashi-machi, Sanda, Noboru Auome A t h ls st Kasuga, NO 76125 y, gen ,or irm- 1c ae l'l er ami-lchibunkatamachi, both of l 57] ABSTRACT Okyo, Japan A thread take-up lever IS reciprocable in vertical di- [22] Filed: June 22, 1972 rection and receives thread from a thread tensioning [2]] APPL No; 266,526 device. Intermediate the take-up lever and the tensioning device the thread is supplied to a thread guide which is displaceable in parallelism with the movel l Foreign Application Priority Dam ment of the take-up lever between an upper and a June 22, 1971 Japan 46/44513 lower position. A dial is movable to at least two positions and is connected with the thread guide by link- [52] U.S. Cl. 112/246 age means so that the thread guide moves between its [51] Int. Cl D05b 49/00 upper and lower positions in dependence upon the [58] Field of Search I l2/24l, 242, 243, 246, 254, movement of the dial to the respective positions of the 112/255 latter. Depending upon whether the thread guide is in its upper or lower position the amount of thread sup- [56] References Cited plied to the take-up lever is varied, that is it is either UNITED STATES PATENTS increased or decreased- 2,l84,929 l2/l939 Nunn ll2/246 7 Claims, 3 Drawing Figures 1 SEWING MACHINE BACKGROUND OF THE INVENTION The present invention relates to a sewing machine in general, and more particularly to a sewing machine with a shiftable thread guide and which is capable for use in such stitching operations as lock stitching, chain stitching and other types of stitchings where different amounts of the upper thread supplied to the needle are required.

Most modern sewing machines can be used for the usual lock stitching as well as for chain stitching and for other types of stitching. Depending upon the type of stitching which is to be done, different amounts of upper thread must be supplied to the needle. For instance, when the machine is used for chain stitching, then less upper thread should be supplied to the needle than if the machine is used for lock stitching. If, therefore, the amount of thread supplied to the needle, and in particular the amount of upper thread so supplied, is not varied when the sewing machine is switched in use from lock stitching to chain stitching, or vice versa, the stitch obtained will not be correct.

The prior art has recognized this problem and has proposed to solve it by supplying such a sewing machine with a special thread guiding attachment, located between the lower positioned thread hook guide and the thread take-up lever. However, experience has shown that this can be troublesome when the upper thread is passed through the thread guiding arrangement on the way to being threaded into the needle, if the attachment is located in the machine frame and becomes accessible only when a part of the top plate of the machine frame is open. The solution which offered itself to this problem was to locate the thread guiding attachment at the exterior of the machine frame. In that case, however, the arrangement is an impediment when lock stitching is to be carried out. Moreover, and generally speaking, it has been found that it is timeconsuming and difficult to reset the upper thread to have it pass through the thread guiding attachment when such a prior-art sewing machine is to be switched from the lock stitching to the chain stitching mode, or to reset the upper thread to disengage it from the thread guiding attachment when the machine is to be switched from the chain stitching to the lock stitching mode. Also, it can and does occur that the operator forgets to engage or disengage the thread with the thread guiding attachment when the mode of stitching is switched, from one mode to another, and in that case the resulting sitches and seams will be incorrect and aesthetically displeasing.

SUMMARY OF THE INVENTION It is, accordingly, a general object of the present invention to overcome the disadvantages of the prior art.

More particularly it is an object of the invention to provide an improved sewing machine which is not possessed of the aforementioned disadvantages.

Still more particularly it is an object of the present invention to provide an improved sewing machine in which the supply of upper thread to the needle can be readily varied in dependence upon different types of stitching operations.

Another object of the invention is to provide such a sewing machine in which the adjustment for varying the amount of upper thread supplied to the needle can be carried out without requiring the operator to exchange any thread guiding attachment, or to disengage or engage the thread with such a thread guiding attachment.

In pursuance of these objects, and of others which will become apparent hereafter, one feature of the invention resides in a sewing machine, comprising a thread take-up lever mounted for reciprocatory movement in an upright path, and a thread tensioning device for tensioning of thread which is supplied from a thread source to the take-up lever. A thread guide is mounted for displacement in parallelism with the upright path between an upper and a lower position and is interposed between the take-up lever and the tensioning device in engagement with the thread supplied from the latter to the former. A dial is movable to at least two positions and linkage means links the thread guide with the dial so that the thread guide is displaced to its upper and lower positions in the thread guide with the dial so that the thread guide is displaced to its upper and lower positions in response to movement of the dial between the two positions thereof. In this manner the amount of thread supplied to the take-up lever can be increased and decreased.

By resorting to the present invention the sewing ma chine can be readily adjusted for different stitching operations, that is greater or lesser amounts of upper thread can be supplied to the needle without difficulties in dependence upon the requirements of a particular stitching operation, without the operator having to effect any engagement of the thread with or disengage ment from the thread guiding attachment.

The invention provides for a sewing machine in which the seams which are sewn in the different types of stitching operations will always be proper and tight,

because the amount of thread can be readily adjusted for the particular stitching operations, such adjustment being capable of carrying out by simple manipulation of a readily used and understood dial.

The inventibn also provides a sewing machine wherein the shiftable thread guide is of simple structure, can be inexpensively produced and readily as sembled with the remaining components of the machine.

The novel features which are considered as characteristic for the invention are set forth in particular in the appended claims. The invention itself, however, both as to its construction and its method of operation, together with additional objects and advantages thereof, will be best understood from the following de scription of specific embodiments when read in connection with the accompanying drawing.

BRIEF DESCRIPTION OF THE DRAWING FIG. 1 is a fragmentary perspective view of a sewing machine head incorporating one embodiment of the invention, with certain components omitted for the sake of clarity;

FIG. 2 is a view analogous to FIG. I but illustrating the embodiment of the present invention in detail; and

FIG. 3 is a perspective fragmentary detail view of FIG. 2 on an enlarged scale.

DESCRIPTION OF THE PREFERRED EMBODIMENTS Discussing now the drawing in detail it will be seen that in FIGS. 1-3 reference numeral 1 designates a generally U-shaped thread guide which is provided on the sewing machine head 100. The thread guide 1 has a pair of parallel walls defining between one another a space 2, and a transverse extension 3 which projects from one of these walls, The thread guide is also pro vided in at least one of the walls with a substantially bay-shaped slot 2a as a guide entrance for the upper thread 27 supplied from a non-illustrated thread supply source (bobbin or the like) to the similarly nonillustrated needle.

A hook-shaped resilient element 4 is provided in the thread guide 1 and in part traverses the slot 20. The guide 1 itself is shiftably mounted on a pair of upright elongated guide plates 7, 7 mounted on the machine frame 6 on one side of the vertical path in which a thread take-up lever can reciprocate The thread guide 1 is positioned between the guide plates 7, 7, and carries on one wall two or more (two shown) spaced projections or pins 9, 9 which slidably extend into an elongated guide slot 8 which is formed in one of the guide plates 7, 7 and extends in parallelism with the upright path of movement of the lever 5. Thus, the thread guide 1 may be vertically shifted intermediate the guide plates 7, 7 between an upper and a lower position, being guided during such shifting by the displacement of the pins 9, 9 in the slot 8.

The transverse extension 3 ofthe guide 1 carries another projection or pin 10 which is engaged by a forked portion 12 provided at one end of an actuating lever 11. The other end of the lever H is turnably supported on a fixed shaft 13 mounted in the machine frame 6. This other end of lever 11 is also provided with arm portions 14 and 15 of which the former is engaged by a tension spring 16 tending to displace the lever 11 in clockwise direction (see FIG. 2) whereby the thread guide 1 tends to be shifted to its upper position along the plates 7, 7 and the slot 8.

The arm portion 15 of the lever 11 is connected at 15a to one end 18 ofa connecting rod 17, the other end of which is designated with reference numeral 19 and connected at 190 to the upper end of a cam follower lever 20. The latter is turnably mounted on a fixed shaft 21 secured in the machine frame 6. A follower portion 200 of the lever is in engagement with a cam 22 under the action ofthe tension spring 16. The cam 22 is secured on a control shaft 24 which is turnably mounted to extend across the machine frame and which carries at its free end extending outwardly from the machine frame an operating dial 23. The machine has a reference mark 28 (see FIG. 1) and the dial carries in the illustrated embodiment two letter designations C and S which can be respectively brought into registry with the mark 28 by appropriate twisting ofthe dial 23.

Reference numeral 25 [see FIG. I) designates a thread tensioning device of the type known per se and mounted on the other part of the sewing machine head 100. It can be adjusted by the adjacent operating portion or regulator 26. The upper thread 27 is supplied by the non-illustrated upper thread source and guided through the thread tensioning device 25. It is then placed into engagement with the hoolcshaped resilient element 4 of the thread guide 1, passed to the eyelet SI provided at the free end of the thread take-up lever 5, and from there to the eyelet of the non-illustrated needle.

When it is desired to adjust the illustrated sewing machine for lock stitching operation, chain stitching operation or the like, the dial 23 is turned, resulting in a concomitant turning of the cam 22 on shaft 24, and in a movement of the follower lever 20 around the shaft 21. If the lever 20 is turned in clockwise direction against the action of the spring 16, then the configuration of the cam 22 will result in the connecting rod 17 turning the lever 11 in counterclockwise direction about the shaft 13 againstthe action of the spring [6. The result of this will be to shift the thread guide 1 to the lower position thereof along the vertical guide plates 7, 7 and the slot 8. If, on the other hand, the lever 20 is turned in counterclockwise direction, the lever 11 is turned in clockwise direction around the shaft 13 under the action of the spring 16 and the thread guide I will then be shifted to the upper position, the terms upper and lower position always being understood with reference to the upper and lower ends of the drawing.

In the illustrated embodiment it will seen that if the dial 23 is rotated so that the mark S is set against the reference mark 28, the guide 1 is shifted to the lower position as shown in the solid lines in FIG. 1. Conversely, if the dial 23 is twisted to place the mark C opposite the reference mark 28, the thread guide 1 is shifted to the broken-line upper position shown in FIG. 1. If chain stitching is to be carried out with the sewing machine, the thread guide 1 is shifted to the upper position whereby the thread guide path from the upper thread supply source to the needle is shortened and the amount of thread supplied to the needle by the vertical reciprocatory movement of the thread take-up lever 5 is descreased. On the other hand, if lock stitching is to be carried out, the thread guide 1 is shifted to its lower position to thereby lengthen the thread guide path and increase the amount of upper thread supplied to the needle.

lfit is important to prevent any stitching carried out from causing shrinkage in the material which is sewn, a predetermined configuration of the cam 22 can be used to properly position the thread guide 1 on the guide plates 7, 7 so that the proper amount of upper thread may be supplied to the needle, It will also be understood that although only a single cam 22 is shown on the control shaft 24, a plurality of cams may be provided on one and the same shaft, so that they may cooperate with thecorresponding control parts in synchronized or separate relation.

It will be understood that each of the elements de' scribed above, or two or more together, may also find a useful application in other types of constructions differing from the types described above.

While the invention has been illustrated and described as embodied in a sewing machine, it is not in tended to be limited to the details shown, since various modifications and structural changes may be made without departing in any way from the spirit of the present invention,

Without further analysis, the foregoing will so fully reveal the gist of the present invention that others can by applying current knowledge readily adapt it for various applications without omitting features that, from the standpoint of prior art, fairly constitute essential characteristics of the generic or specific aspects of this invention and, therefore, such adaptations should and are intended to be comprehended within the meaning and range of equivalence of the following claims.

What is claimed as new and desired to be protected by Letters Patent is set forth in the appended claims:

1. In a sewing machine, a combination comprising a thread take-up lever mounted for reciprocatory movement in an upright path; a thread tensioning device for tensioning of thread which is supplied from a thread source to said take-up lever; a thread guide mounted for displacement in parallelism with said upright path between an upper and a lower position, said thread guide being interposed between said takeup lever and tensioning device for engaging of thread supplied from the latter to the former; a dial movable to at least two positions; and linkage means linking said thread guide with said dial so that the thread guide is displaced to its upper and lower positions in response to movement of said dial between said two positions, whereby the amount of thread supplied to said take-up lever can be increased and decreased.

2. A combination as defined in claim 1; further comprising wall means having a guide slot extending in parallelism with said upright path; and wherein said thread guide comprises at least two projections extending into said guide slot and slidable therein so as to guide said thread guide for displacement of the same.

3. A combination as defined in claim 2, said sewing machine having a frame, and said wall means comprising at least one guide plate mounted on said frame and having said guide slot.

4. A combination as defined in claim 2, said sewing machine having a frame, and said wall means comprising a pair of transversely spaced at least substantially thread.

Claims

1. In a sewing machine, a combination comprising a thread takeup lever mounted for reciprocatory movement in an upright path; a thread tensioning device for tensioning of thread which is supplied from a thread source to said take-up lever; a thread guide mounted for displacement in parallelism with said upright path between an upper and a lower position, said thread guide being interposed between said take-up lever and tensioning device for engaging of thread supplied from the latter to the former; a dial movable to at least two positions; and linkage means linking said thread guide with said dial so that the thread guide is displaced to its upper and lower positions in response to movement of said dial between said two positions, whereby the amount of thread supplied to said take-up lever can be increased and decreased.

4. A combination as defined in claim 2, said sewing machine having a frame, and said wall means comprising a pair of transversely spaced at least substantially parallel guide plates mounted on said frame and at least one of which is provided with said guide slot.

5. A combination as defined in claim 2, wherein said projections are guide pins.

6. A combination as defined in claim 1, wherein said thread guide is of substantially U-shaped configuration and has a main portion and a transverse extension portion; and wherein said linkage means is connected with said transverse extension portion.

7. A combination as defined in claim 1, wherein said thread guide includes a substantially hook-shaped resilient element adapted for engagement with said thread.