US3581687A

US3581687A - Bobbin winding device for sewing machines

Info

Publication number: US3581687A
Application number: US797391A
Authority: US
Inventors: Gunter Meier; Willi Meier
Original assignee: GM Pfaff AG
Current assignee: GM Pfaff AG
Priority date: 1968-02-08
Filing date: 1969-02-07
Publication date: 1971-06-01
Anticipated expiration: 1988-06-01
Also published as: CH479742A

Abstract

A bobbin winding device for sewing machines comprises a bobbin holder having a shaft journaled in a wall of the sewing machine housing and a driven friction wheel having a shaft mounted telescope-fashion in said first shaft and urged into driving engagement with a continuously rotating driving wheel by a spring operably interposed between said shafts. A flat control spring is disposed at right angle to said shafts and has an intermediate portion urging the driven wheel to a position of disengagement from the driving wheel. A slide operable by a control member between a rest position and an operative position and camming with said control spring enables the latter to be disengaged from the driving wheel, to cause engagement of the driving wheel with the driven wheel for the starting of a bobbin winding operation. The control member acts as a stop entering the outer space between the flanges of a bobbin being wound, to initiate the automatic stoppage of the winding operation upon the outer thread winding turns engaging said stop.

Description

United States Patent BOBBIN WINDING DEVICE FOR SEWING MACHINES 5 Claims, 3 Drawing Figs.

U.S.Cl 112/218 Int. Cl Bh 54/18 Field ofSearch.. ll2/218A,

References Cited UNITED STATES PATENTS 3,059,601 10/1962 Hedegaard 112/218 3,322,084 5/1967 Daman 112/218 FOREIGN PATENTS 273,922 6/1951 Switzerland 112/218 Primary Examiner-H. Hampton Hunter Attorney- Greene & Durr ABSTRACT: A bobbin winding device for sewing machines comprises a bobbin holder having a shaft journaled in a wall of the sewing machine housing and a driven friction wheel having a shaft mounted telescope-fashion in said first shaft and urged into driving engagement with a continuously rotating driving wheel by a spring operably interposed between said shafts. A flat control spring is disposed at right angle to said shafts and has an intermediate portion urging the driven wheel to a position of disengagement from the driving wheel. A slide operable by a control member between a rest position and an operative position and camming with said control spring enables the latter to be disengaged from the driving wheel, to cause engagement of the driving wheel with the driven wheel for the starting of a bobbin winding operation. The control member acts as a stop entering the outer space between the flanges of a bobbin being wound, to initiate the automatic stoppage of the 2,056,829 10/1936 Colegrove et a1 112/218 winding operation upon the outer thread winding turns engag 4/1952 Hirsch et al 112/218 ing said stop.

9 21 m am 2 i 77 13 I PATENTED'JUN new 358-1; 687

INVENTORS WWI-ER V 8 BY VV/LL/ HEM-=0 Mm. RAW

A from 4/5 y BOBBIN WINDING DEVICE FOR SEWING MACHINES The present invention relates to bobbin winding devices for sewing machines of the type including a rotatively mounted bobbin holder and a driven friction wheel fast for rotation with an axiably slidable relative to the shaft of said holder, said wheel being subject to the action of a coupling spring urging the same into engagement with a driving wheel, on the one hand, and to the action of a relatively heavier decoupling or control spring operable between an operative position and a rest position by means of a control key or the like member acting as a stop or sensor of a predetermined amount of thread wound upon the bobbin.

More particularly, the known bobbin winding devices ordinarily comprise a bobbin winding shaft having one end adapted to receive a bobbin to be wound and carrying a friction wheel at its opposite end arranged for deflection or displacement towards and away from a driving wheel. Disregarding the provision of a special cover enclosing the winding device, the projection of at least the free end of the bobbin shaft beyond the housing of the sewing machine makes it necessary, in the interest of ensuring an adequate space for both the mounting and displacement of the bobbin shaft, to provide a sufficiently large aperture in the sewing machine housingwall, whereby to allow dust and other foreign matter to penetrate into the interior of the machine. While this disadvantage may be obviated by the use of an axially displaceable bobbin shaft, such a construction is objectionable by project ing to an increased extent beyond the housing in its rest position, as determined by its operating stroke or displacement.

There are other known bobbin winding devices wherein the bobbin shaftis journaled in a special frame or mounting fixture disposed within the housing of the sewing machine, with only the driven friction wheel mounted for rotation at one end of said shaft being displaceable in the axial direction. The driven friction wheel is urged, by the aid of a compression spring arranged with one end abutting against the wheel and with its opposite end abutting against the frame, into engagement with a driving wheel. Further disposed within said frame, in the vicinity of and parallel to the bobbin shaft, is an axially displaceable switching rod having one of its ends pivotally connected to one end of a two-armed lever also supported by said frame. The remaining end of the lever engages, on the side opposite to thedriving wheel, a collar of the driven wheel, while an additional and relatively heavier compression spring mounted upon said rod acts to urge the latter, via said lever and in turn the driven, wheel away from the driving wheel in the rest position of the device.

In operation of the above known bobbin winding devices, the switching rod is retracted, against the action of its compression spring, from the frame to an extent as to deflect the lever, to release the driven wheel and to cause an arcuate resilient feeler to enter the space between the flanges of the bobbin to be wound, whereupon release of the rod will result in its arrest in the switching position by engagement with the inside of the frame. Such a control and arrest of the winding device has the great disadvantage, among others, that the arcuate feeler is in constant sliding engagement with the inside wall of one of the bobbin flanges during the entire winding operation, whereby to result in possible damage to the latter after prolonged use, not to mention the sliding or friction noise caused thereby. Under especially unfavorable conditions, such for instance as during the formation of loose turns of the thread being wound or in the case of one-sided or uneven winding, it may happen that the thread will be caught between the feeler and the bobbin flange, to result in damage to or completebreakage of the thread.

An important object of the present invention is, therefore, the provision of an improved bobbin winding device for sewing machines of the referred to type by which the foregoing and related disadvantages and shortcomings of the known bobbin winders are substantially eliminated or minimized.

A more specific object of the invention is the provision of a bobbin winder of the type described which, upon being set in operation manually, will be arrested automatically upon the winding of a predetermined amount of thread by the action of a feeler responsive to the diameter of the spool of thread being wound, substantially without involving any frictional or sliding engagement with the bobbin flanges or other parts of the device.

Still another object of the invention is the provision of an automatic bobbin winding device of the referred to type, especially suitable for mounting in an unobtrusive manner in the top wall of a sewing machine housing adjacent to the hand wheel, which device projects to a minimum distance, or does practically not project, from the outer surface of said wall in both the operative and inoperative positions of said device.

Yet another object of the invention is the provision of bobbin winding mechanism of relatively simple and compact construction, suitable for structural incorporation in a wall portion, preferably the top wall, of a conventional sewing machine.

The invention, both as to the foregoing and ancillary objects as well as novel aspects thereof, will be better understood from the following detailed description of a preferred practical embodiment, taken in conjunction with the accompanying drawing forming part of this specification and in which:

FIG. 1 is a perspective view showing part of the cover or top wall of the overhanging arm forming part of the housing of a conventional sewing machine and having mounted therein a bobbin winding device constructed in accordance with the principles of the invention;

FIG. 2 is a sectional view, to an enlarged scale, taken on line 11-11 of FIG. 1 and showing the winding mechanism in the operative or engaged position of the driving and driven wheels; and

FIG. 3 is a plan view of FIG. 2, shown with the cover omitted, to reveal the inside construction of the device.

Like reference numerals denote like parts in the different views of the drawing.

With the foregoing objects in view, the invention, according to one of its aspects, involves generally the provision of a bobbin winding device of the referred to type, wherein the driven friction wheel is fitted with a shaft telescoping within the shaft of the bobbin holder, with a coupling spring urging the driven wheel into engagement with a driving wheel disposed operably between both said shafts, wherein furthermore the decoupling spring is in the form of a flat bent spring disposed at right angle to the axis of the bobbin winder shaft and having an intermediate portion engaging the side of the driven wheel adjoining the driving wheel, and finally which device includes a control slide parallel to the axis of said shaft and disposed between the housing wall of the machine and the decoupling spring, said slide having a bevelled end portion adapted to cam with the free bent end of said decoupling spring, in such a manner as to disengage the driven wheel from the driving wheel, in the normal or rest position of said device, by said decoupling spring acting against said coupling spring, on the one hand, and to effect engagement of said wheels by said coupling spring and to commence a bobbin winding operation in the operative position of the slide, on the other hand.

By the arrangement of the control slide at right angle to the bobbin winding axis, the pressure exerted by the decoupling spring in the inoperative position of the device and acting in the direction of the bobbin axis upon the control slide is directly imparted to the housing, without affecting the axial position of the thread feeler relative to the bobbin axis, This in turn makes it possible, in bobbin winding devices having a bobbin holder journaled about a stationary axis, to ensure a positive and uniform winding action and in turn a safe determination of the diameter of the outermost thread winding turns with a sufficiently close accuracy.

A further advantage of the bobbin winder according to the present invention is the fact that, aside from the saving of space resulting from the use of a flat decoupling spring in conjunction with the telescopic mounting of the bobbin holder and driven wheel shafts, the entire device assumes a rather flat construction, whereby to enable its ready and unobtrusive structural incorporation in existing sewing machine constructrons.

According to an improved feature of the invention, to enable a ready mounting and removal of a bobbin to be wound, the bobbin holder is fitted with a permanent holding magnet formed with a dish-shaped supporting surface and a central aligning stud conforming with the shape of the bobbins. With an arrangement of this type, thebobbin holder may be mounted with its supporting surface substantially flush with the outer surface of the housing wall of the sewing machine, thus giving the winder a harmonic and unobtrusive appearance, in the manner as will become further apparent as the description proceeds in reference to the drawing.

Referring to the drawing, the numeral 1 denotes the cover of the overhanging arm of a conventional sewing machine in which is mounted, close to the handwheel of the machine, a bobbin winding device according to the invention, said device comprising a bobbin support or holder collectively denoted by the numeral 2, a driven friction wheel 3 and a control member 4 serving for the connection and disconnection of the device for the carrying out of a bobbin winding operation.

The bobbin holder, in the example shown, consists of a hollow shaft 5 having a flange 6 and being rotatively mounted in a recess in the top wall of the cover 1 through a shouldered intermediate insert or bearing 8 fitted in said recess, shaft 5 being locked against axial displacement relative to said insert by a clamping washer 7.

Mounted upon the flange 6 are an outer annular permanent holding magnet 10, disposed substantially flush with the outer surface of the cover 1, on the one hand, and a central aligning stud 11 of nonmagnetic material, on the other hand. In order to ensure maximum magnetic holding force, the upper slightly inwardly chamfered surface of the magnet conforms with the supporting surface of the bobbin 9 mounted concentrically with the stud 11.

Disposed telescope-fashion within the hollow bobbin holder shaft 5 is the hollow shaft 12 of the driven friction wheel 3 of the drive of the winding device which further comprises a driving wheel 16 which is continuously rotated by the main drive shaft (not shown) of the sewing machine in any suitable manner. In the embodiment shown, both wheels 3 and 16 are in the form of bevel friction wheels. Hollow shaft 12 has one or a pair of diametrical slots 13 which are engaged by a crosspin 14 mounted within the shaft 5, to connect the wheel 3 for rotation with the bobbin holder, while allowing of relative axial displacement of the shafts. Disposed within the inner space of the hollow shaft 12 is a coiled compression spring 15 abutting at one end against the pin 14 and abutting at its opposite end against the upper surface of the wheel 3, whereby to normally urge said wheel into engagement with the driving wheel 16 in the operative position of the winder as shown in FIG. 2.

Secured cantilever-fashion to the inside of the cover 1 is a flat bent control spring 17 disposed substantially at right angle to the axis of the bobbin holder 2, said spring having an intermediate portion adapted to engage the lower surface of the wheel 3, to lift and disengage the same from the driving wheel against the action of spring 15, in the rest or inoperative position of the winding device. In the operative position of the device as shown in FIG. 2, the spring 17 is disengaged from the wheel by the position of the control member 4, in the manner further understood from the following.

For the latter purpose, the control member includes a slide 19, disposed on the side of the wheel 3 opposite to the spring 17, said slide being displaceably mounted in the frame or cover 1 in a direction substantially parallel to said spring or at right angle to the axis of the bobbin holder. The slide 19 carries a connecting member 20 passing through an aperture in the cover and terminating in an operating knob or key 21 projecting outwardly from said cover, on the one hand, and has a chamfered end adapted to cam with the free bent end 18 of the spring 17, on the other hand, in the manner as will become more apparent from the description of the operation of the device.

According to an improved feature of the invention, the key 21 acts as a stop or feeler to ascertain a definite amount of thread wound upon the bobbin 9, thereby to initiate an automatic stoppage of the winding operation, after manual starting of a bobbin winding cycle of the device by means of the key 21. As can be seen from FIG. 2, showing the operative or starting position of the key, the end of the latter freely engages the outer space between the flanges of the bobbin 9 to an extent, to ensure an optimally uniform winding and sensing of the outer diameter of the coil being wound, on the one hand, while principally rendering impossible any clamping of the thread between the key and the flanges of the bobbin. Preferably, the lengthwise dimension of the key 21 is such as to fully cover the aperture in the housing 1 passing the member 20, in both the inoperative and operative positions of the key.

In operation, after an empty bobbin 9 has been placed upon the holder 2 in the manner shown, to be held by magnetic attraction by the magnet 10, the key 21 and with it the switching member 4 are operated from the rest position, FIG. 3, in the direction towards the winder axis to the operative position of the winder, FIG. 2. As a consequence, the key 21 enters the outer space between the flanges of the bobbin as shown in FIG. 2, while the chamfered end of the control slide 19 passes beyond the bent 18 of the spring 17, whereby to depress the latter against its own resilient force, to release the driven wheel 3, and to cause the latter to be operated into engagement with the driving wheel 16 by the action of the spring 15. This in turn initiates the commencement of a bobbin winding operation.

The device may be designed for both manual starting and stopping of a winding operation or cycle. In this case, the key 21 is designed as a switch without entering the bobbin 9. After a desired amount of thread has been wound, the operation is arrested by returning the key to its inoperative position, or away from the winding axis of the device, in a manner readily understood.

In the case of automatic stoppage, as shown in FIG. 2, after the winding has been manually started in the manner described, the outer thread winding turns on the bobbin engaging, upon reaching a predetermined coil diameter, the inner end of key 21 initially act to displace the key 21, and with it the slide 19, towards its rest position, whereby to cause the bent end 18 of the spring 17 to cam with the bevelled surface of the slide 19, in such a manner as to exert a component force in the longitudinal direction of the slide, resulting thereby in the instant displacement of the slide and in turn of the entire winding device to its rest position by allowing spring 17 to return into engagement with the wheel 3 and disengaging the latter from the driving wheel 16.

In the foregoing the invention has been described in reference to a preferred exemplary device or embodiment. It will be evident however that variations and modifications, as well as substitution of equivalent elements or devices for those shown for illustration, may be made without departing from the broader scope and spirit of the invention. The specification and drawing are accordingly to be regarded in an illustrative rather than restrictive sense.

lclaim:

I. In a sewing machine having a housing, a bobbin winder comprising:

1. a bobbin holder having a first shaft journaled in a wall portion of said housing and locked against axial displacement, said holder adapted to receive a bobbin to be wound,

2. a continuously rotating driving wheel within said housing,

3. a driven wheel having a second shaft and means axially slidably connecting said second shaft to said first shaft,

4. a biasing spring interposed between said first and second shafts and directly bearing on one side of said driven wheel, to urge said driven wheel in the direction of engagement with said driving wheel,

5. a bent flat coupling spring secured at one end to said housing in cantilever-fashion, said spring having a free curved end portion and an intermediate portion directly bearing on the opposite side of said driven wheel, to urge said driven wheel in the direction of disengagement from said driving wheel against the action of said biasing spring, and

6. a control slide mounted in said housing transversely to the axis of said bobbin holder and operable between a rest positioniand an operative position, said slide having an end portion adapted to cam with the end portion of said coupling spring, whereby to retract said coupling spring from said driven wheel, to efiect driving engagement of said driven wheel with said driving wheel by said biasing spring in the operative position of said slide, and to disengage said driven wheel from said driving wheel by said coupling spring in the rest position of said slide, respectively.

2. A bobbin winder as claimed in claim 1, wherein said bobbin holder includes an annular permanent holding magnet and a central nonmagnetic aligning stud substantially flush with the outer surfaceof said wall portion, the surface of said magnet and saidstud conforming to the bobbin to be wound.

3. A bobbin winder as claimed in claim 1, wherein said first and second shafts are hollow shafts interengaging one another telescope-fashion, with the first outer shaft fitted with a crosspin engaged by diametrical slots in the second inner shaft and with said biasing spring being a coiled compression spring disposed within said second shaft with one end thereof bearing against said pin and with its opposite end bearing against said driven wheel.

4. A bobbin winder as claimed in claim 1, including an operating member connected tosaid slide and extending through an aperture of saidwall portion, to enable starting and stopping of the bobbin winding operations.

5. A bobbin winder as claimed in claim 1, including an operating member upon the outside of said wall portion adjoining said bobbin holder, connecting means between said slide and said member passing through an aperture of said wall portion, and a thread feeler extending from said member and adapted to enter, in the operative position of said slide, the space between the flanges of a bobbin being wound, to initiate the automatic stoppage of the bobbin winding operation upon the outer thread turns engaging said feeler, to displace said member, upon previous manual operation of said slide by said member to its operative position for the starting of a bobbin winding operation.

Claims

1. In a sewing machine having a housing, a bobbin winder comprising:

2. a continuously rotating driving wheel within said housing,

2. A bobbin winder as claimed in claim 1, wherein said bobbin holder includes an annular permanent holding magnet and a central nonmagnetic aligning stud substantially flush with the outer surface of said wall portion, the surface of said magnet and said stud conforming to the bobbin to be wound.

4. A bobbin winder as claimed in claim 1, including an operating member connected to said slide and extending through an aperture of said wall portion, to enable starting and stopping of the bobbin winding operations.

6. a control slide mounted in said housing transversely to the axis of said bobbin holder and operable between a rest position and an operative position, said slide having an end portion adapted to cam with the end portion of said coupling spring, whereby to retract said coupling spring from said driven wheel, to effect driving engagement of said driven wheel with said driving wheel by said biasing spring in the operative position of said slide, and to disengage said driven wheel from said driving wheel by said coupling spring in the rest position of said slide, respectively.