US3303804A

US3303804A - Unitary presser bar spring regulating devices

Info

Publication number: US3303804A
Application number: US404048A
Authority: US
Inventors: Lesort Paul
Original assignee: Singer Co
Current assignee: Singer Co
Priority date: 1964-10-15
Filing date: 1964-10-15
Publication date: 1967-02-14
Anticipated expiration: 1984-02-14
Also published as: FR1449156A

Description

Feb. 14, 1967 P. LESORT 3,303,804

UNITARY PRESSER BAR SPRING REGULATING DEVICES Filed Oct. 15, 1964 INVENTOR.

PAUL LESORT ATTORNEY United States Patent 3,303,804 UNITARY PRESSER BAR SPRING REGULATING DEVICES Paul Lesort, Freneuse, France, assignor to The Singer Company, New York, N.Y., a corporation of New Jersey Filed Oct. 15, 1964, Ser. No. 404,048 3 Claims. (Cl. 112235) This invention relates to sewing machines and more particularly to a unitary regulating device for adjusting or regulating the pressure which a presser bar spring applies to the presser bar of a sewing machine.

Presser bar spring regulating devices are old and well known and in fact United States Patent No. 3,055,326 shows a device for regulating the spring pressure of a presser bar spring. However, prior art presser bar spring regulating devices have been more or less built into the sewing machine and were not constructed as a unit that could easily be applied to and removed from a sewing machine. Therefore, one of the primary objects of the present invention is to provide an improved presser bar spring regulating device of the type herein shown that can be assembled as a unit and then easily applied to or removed from a sewing machine.

Another object of the invention is to provide an improved presser bar spring regulating device which is constructed from a few simple parts that can be manufactured economically.

A still further object of the invention is to provide an improved unitary spring regulating device for the presser bar spring of a sewing machine.

With the above and other objects in view, as will hereinafter appear, the invention comprises the devices, combinations and arrangements of parts hereinafter set forth and illustrated in the accompanying drawings of a preferred embodiment of the invention, from which the several features of the invention and the advantages attained thereby will be readily understood by those skilled in the art.

In the drawings:

FIG. 1 is a fragmentary elevational end view of a sewing machine equipped with a unitary presser bar spring regulating device embodying the present invention, the face plate of the sewing machine having been removed to show the internal construction,

FIG. 2 is a horizontal sectional view taken substantially on the line 22 of FIG. 1, but showing the face plate,

FIG. 3 is a vertical sectional view taken substantially on the line 3-3 of FIG. 1,

FIG. 4 is a front elevational view showing the unitary presser bar spring regulating device of this invention before it has been applied to a sewing machinne, and

FIG. 5 is an exploded perspective view showing certain parts of the mechanism illustrated in FIGS. 1 through 4.

Referring more particularly to FIG. 1 of the drawings, there is shown a portion of a sewing machine 16 having a work support 17 fitted with a throat plate 18 through which projects a feed dog 19. A presser foot 21 carried by the lower end of a presser bar 22 cooperates with the feed dog 19 to hold and forward work (not shown). A midportion of the presser bar 22 is vertically slid-able in a bore 23 formed in a lower portion of the head 24 of the sewing machine 16, and the upper end of the presser bar 22 is slidably mounted in a bore 26 in a boss 27 formed integral with the upper end of the head 24. Secured, as by a screw, to the presser bar 22 is a collar 28 having a radially extending finger 29 which is slidably received in a slot 31 formed in the head 24. The slot 31 and the finger 29 prevents the presser bar 22 from turning and the slot 31 also accommodates a presser lifter 32 which -is fulcrumed on a pivot screw 33 threaded into a boss formed in the head 24. When the lifter 32 is raised, it lifts the presser bar 22 against the downward bias of a helical compression spring 36 coiled around the presser bar 22. The lower end of the spring 36 abuts the upper end of the collar 28, and the upper end of the spring 36 is engaged by a member presently to be described. A face plate 37 swings on a single hinge screw 38 and when the face plate 37 is closed, it encases most of the previously described mechanism as well as the unitary presser bar regulating device 44 presently to be described.

The unitary presser bar regulating device 44, as best shown in FIGS. 4 and 5, comprises essentially six parts, namely, a guide member 45, two screws 46-46 for securing the member 45 to the sewing machine boss 27, a spring abutment bracket 47 slidably mounted on the member 45, an adjusting knob 48, and a shouldered pivot stud or screw 49 for turnably mounting the adjusting knob 48 on the guide member 45.

The guide member 45 is in the form of an elongated rectangular parallelepiped having adjacent to its upper end a pair of unthreaded holes 51-51 for receiving the mounting screws 46-46, and toward its lower end a threaded hole 52 for accommodating the threaded end of the pivot screw 49. The lowermost end of the member 45 is bifurcated to provide an open ended slot 53. The upper end of the spring abutment bracket 47 is formed with a horizontally extending arm 61, the free end of which is bifurcated to form abutment fingers 62-62 and the main body 63 of the bracket 47 is in the form of a crosshead having facing

parallel grooves

64 and 66 for slidably mounting the bracket 47 on the member 45. The wall 67 of the bracket 47 between the two

grooves

64 and 66 is formed with a struck out follower 68 which, as best seen in FIG. 3, is long enough to pass through the slot 53 and extend beyond the front portion of the bracket 47.

The adjusting knob 48, which has a central hub-aperture 71, is similar to and serves the same purpose as the pressure regulating member shown in United States Patent No. 3,055,326, supra, and the knob 48 is formed on its inner side with a spiral cam track 72 and, when the unitary regulator device 44 is assembled, the cam track 72 is disposed contiguous to the guide member 45. As best illustrated in FIG. 5, the cam track 72 has a plurality of angularly spaced peripheral notches 72D, 721, 722, 723, 724, 72-5, 726, 727, and 728, each notch being disposed at a different radial distance from the axis of the pivot stud 49. The cam track 72 also has a substantially radial wall 73 extending from the radial notch 72D nearest the axis of the pivot stud 49 to the outer periphery of the cam track 72 adjacent to the notch 728 that is most remote from the axis of the pivot stud 49. The follower 68 extends through the open ended slot 53 and tracks the periphery of the cam track 72 to seat in any one of the selected peripheral notches 72D, 721, 722, 723, etc. The distance of the selected notch in which the follower 68 is seated from the axis of the pivot stud 49 determines the position of the abutment fingers 62-62 on the presser bar 22 and thus influences the compression applied to the spring 36. When the follower 68 rests in notch 72D, the fingers 62 engage the presser bar 22 at a high location and thus the spring 36 is relaxed. In this position the presser foot 21 is not forced against the feed dog 19 and the sewing machine 16 may be used for darning. As the knob is turned so that the follower 68 rests successively in the notches 721, 722, 72-3, etc., the spring 36 is successively compressed until, when the follower rests in notch 728, the presser foot 21 presses on the feed dog 19 with maximum pressure.

The outer face of the knob 48 is formed with a frustoconical dial 76 having indicia D, 1, 2, etc-8 corresponding to each of the peripheral notches 72D, 721, 722,

723, etc. of the cam track 72. Preferably the indicia corresponding with each notch is disposed on the dial at an angle of approximately 90 in a counterclockwise direction as viewed in FIG. 1 from the portion of the notch to which it corresponds.

The unitary presser bar spring regulator device 44 is applied to the sewing machine 16 in the following manner. First, the adjusting knob 48 is mounted on the guide member 45 by passing the pivot screw 49 through the hub aperture 71 and by then threading the screw 49 into the threaded hole 52. Next the bifurcated lower end of the guide member 45 is moved downwardly into the grooves 6466 until the follower 68, which passes through the slot 53 engages the cam track 72. Then the abutment fingers 62-62 are placed on top of the spring 36 and the guide member 45 is fastened to the boss 27 by means of the screws 46-46. As soon as this is done, the pressure with which the presser foot 21 engages the feed dog 19 can be adjusted by turning the knob 48. Closing the face plate 37 completely covers the unitary presser bar spring regulating device 44.

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

1. A unitary regulating device for regulating the pressure which a presser bar spring applies to the presser bar of a sewing machine, said unitary regulating device comprising, an elongated apertured guide member provided at one end with an open ended slot, an adjusting knob, a cam track on said knob, means for pivotally mounting said knob on said guide member, an abutment bracket entirely supported by and slidably mounted on said guide member, an arm on said bracket adapted to engage said presser bar spring, a cam follower formed on said bracket and positioned to extend through the open ended slot in said guide member to engage the cam track on said knob, and means for securing said guide member to the said sewing machine.

2. A unitary regulating device for regulating the pressure which a presser bar spring applies to the presser bar of a sewing machine, said unitary regulating device comprising, an elongated apertured guide member provided at one end with an open ended slot, an adjusting knob formed on one face with a dial and on its other face with a cam track, means for pivotally mounting said knob on said guide member, an abutment bracket having a pair of facing parallel grooves for slidably mounting said bracket on said guide member, an arm bifurcated to form a pair of fingers extending outwardly from said bracket and adapted to engage said presser bar spring, a cam follower formed on said bracket and positioned to extend through the slot in said guide member to engage the cam track on said knob, and means for securing said guide member to the said sewing machine.

3. A unitary device for regulating the pressure, which a presser bar spring applies to the presser bar of a sewing machine, said device being adapted to be assembled as a unit and applied to or removed from a sewing machine as a unit, and said device comprising an apertured elongated rectangular parallelepiped shaped guide member provided at one end with an open ended slot, an adjusting knob formed on one face with a dial and on its other face with a cam track, means pivotally mounting said knob on said guide member, an abutment bracket having spaced means for embracing said guide member and thereby slidably mounting said bracket on said guide member, finger means carried by said bracket and adapted to engage said presser bar spring, a cam follower formed on said bracket and positioned to extend through the slot in said guide member to engage the cam track on said knob, and means securing said guide member to said sewing machine.

References Cited by the Examiner UNITED STATES PATENTS 2,554,970 5/ 1951 Adler 112-235 2,874,663 2/1959 Matugas 1l2-236 3,055,326 9/1962 Greulick 112235 3,089,447 5/1963 Shuman l12 235 PATRICK D. LAWSON, Primary Examiner.

Claims

1. A UNITARY REGULATING DEVICE FOR REGULATING THE PRESSURE WHICH A PRESSER BAR SPRING APPLIES TO THE PRESSER BAR OF A SEWING MACHINE, SAID UNITARY REGULATING DEVICE COMPRISING, AN ELONGATED GUIDE MEMBER PROVIDED AT ONE END WITH AN OPEN ENDED SLOT, AN ADJUSTING KNOB, A CAM TRACK ON SAID KNOB, MEANS FOR PIVOTALLY MOUNTING SAID KNOB ON SAID GUIDE MEMBER, AN ABUTMENT BRACKET ENTIRELY SUPPORTED BY AND SLIDABLY MOUNTED ON SAID GUIDE MEMBER, AN ARM ON SAID BRACKET ADAPTED TO ENGAGE SAID PRESSER BAR SPRING, A CAM FOLLOWER FORMED ON SAID BRACKET AND POSITIONED TO EXTEND THROUGH THE OPEN ENDED SLOT IN SAID GUIDE MEMBER TO ENGAGE THE CAM TRACK ON SAID KNOB, AND MEANS FOR SECURING SAID GUIDE MEMBER TO THE SAID SEWING MACHINE.