Sewing Machine Thread Supply Spool Friction Brake

Abstract

A thread spool supporting spindle assembly for mounting on the conventional spool pin atop a sewing machine. The spindle assembly includes structure by which a light friction drag is applied to the spool of thread supported from the spool pin and thereby prevents inertia of the supported spool of thread tending to cause the thread spool to coast ahead when operation of the associated sewing machine is terminated after operating at high speed, such overrunning of the thread spool causing excessive slack in the thread which can subsequently result in thread breakage when the sewing machine is again started at high speed. The spindle assembly of the instant invention may be utilized on any sewing machine which includes a vertical, or substantially vertical, spool pin located atop the sewing machine and includes felt disk structure for initial downward displacement over the spool pin with the diameter of the center opening in the felt disk structure being smaller than the diameter of the pin thereby affording a friction fit between the felt disk structure and the pin so that a thread spool disposed over the pin above the felt disk will drop by gravity into engagement with the felt disk assembly to thus frictionally resist overrunning of the thread spool.

Description

The main object of this invention is to provide an attachment for a conventional sewing machine which may be readily added to the sewing machine and utilized to prevent excessive overrunning of an associated thread spool.

Another object of this invention, in accordance with the immediately preceding object, is to provide a thread spool spindle construction which may be readily applied, in a removable manner, to substantially all sewing machines provided with vertically disposed spool pins there atop.

A final object of this invention to be specifically enumerated herein is to provide a device in accordance with the preceding objects and which will conform to conventional forms of manufacture, be of simple construction and automatic in operation so as to provide a device that will be economically feasible, long lasting and relatively trouble free.

These together with other objects and advantages which will become subsequently apparent reside in the details of construction and operation as more fully hereinafter described and claimed, reference being had to the accompanying drawings forming a part hereof, wherein like numerals refer to like parts throughout.

FIG. 1 is a fragmentary perspective view of a conventional form of sewing machine with the thread spool spindle assembly of the instant invention operatively associated with the spool pin of the sewing machine and a spool of thread mounted on the spindle assembly;

FIG. 2 is an exploded perspective view of the spindle assembly of the instant invention; and

FIG. 3 is an enlarged fragmentary vertical sectional view taken substantially upon the plane indicated by the section line 3--3 of FIG. 1.

Referring now more specifically to the drawings, the numeral 10 generally designates a conventional form of sewing machine including an upper horizontal portion 12 upwardly from which a vertical spool pin 14 projects. Conventionally, a spool 16 of thread 18 is loosely telescoped over and rotatably disposed on the spool pin 14 in a manner such that the spool 16 is free to rotate relative to the pin 14 as the thread 18 is pulled from the spool 16 through the guides 20 and 22 of the sewing machine 10.

When the machine 10 is operating at high speed the thread 18 is unwound from the spool pin 14 in a relatively rapid manner so that when the machine 10 is suddenly stopped the spool 16 tends to rotate in the thread unwinding direction and thereby unwinds sufficient thread 18 from the spool 16 after operation of the machine 10 has been terminated to cause excessive slack in the thread 18 extending from the spool 16. Then, when the machine 10 is suddenly again placed in operation at high speed, the thread 18 is suddenly tensioned and there is a tendency for the thread to be broken.

The spool spindle assembly of the instant invention is referred to in general by the reference numeral 24 and includes a thin walled sleeve 26 which may be telescoped over the pin 14, a pair of vertically spaced felt disks 28 and 30, a pair of felt wedges 32 and 34 for disposition between corresponding diametrically opposite portions of the disks 28 and 30 and a plastic strap 36 having an aperture 38 formed in one end and a pair of metal weights 40 secured to the apertured end of the strap 36 on opposite sides of the aperture 38.

With attention invited to FIGS. 2 and 3 of the drawings it may be seen that the disks are disposed in vertically spaced relation with the wedges 32 and 34 disposed between corresponding pairs of diametrically opposite portions of the disks 28 and 30. The disks 28 and 30 as well as the wedges 32 and 34 are secured together in any convenient manner such as by a glue or adhesive (not shown) and the disk assembly or overall structure comprising the disks 28 and 30 and the wedges 32 and 34 are slipped downwardly over the spool pin 14. The disks 28 and 30 are provided with center apertures 42 and 44 which are at least slightly smaller in diameter than the diameter of the spool pin 14 and thus the disks 28 and 30 have to be forced downwardly over the upper rounded end of the pin 14 and the disks 28 and 30 are frictionally engaged with the pin 14 to thus retard rotation of the disk assembly relative to the pin 14. The end of the plastic strap 36 remote from the aperture 38 is secured between the disks 28 and 30 and between the wedges 32 and 34 in any convenient manner such as by an adhesive or glue (not shown) and the aperture 38 in the weighted end of the strap 36 is of a diameter larger than the diameter of the sleeve 26.

After the disk structure comprising the disks 28 and 30 and the wedges 32 and 34 has been passed downwardly over the spool pin 14, the sleeve 26 is telescoped downwardly over the pin 14 and is rotatable relative to the latter. The lower end of the sleeve 26 abuts against the upper side of the disk 30 and the spool 16 is thereafter downwardly telescoped over the sleeve 26 and the weighted end of the strap 36 is passed over the upper end of the sleeve 14 so that the weighted end of the strap 36 may engage the upper end of the spool 16 while the lower end of the spool 16 rests upon the diametrically opposite portions of the upper disk 30 beneath which the wedges 32 and 34 are disposed.

The apertured end of the plastic strap 36 is disposed in frictional engagement with the upper end of the spool 16 and the lower end of the spool 16 is frictionally engaged with the diametrically opposite portions of the disk 30 having the wedges 32 and 34 disposed thereunder. Accordingly, this frictional engagement of the strap 36 and the disk 30 with the spool 16 tends to retard rotation of the spool and thus to prevent continued rotation of the spool in a thread unwinding direction when the operation of the sewing machine is suddenly terminated from high speed operation. In this manner, the formation of slack in the thread 18 extending from the spool 16 is eliminated and the sewing machine 10 may be again immediately oerated at high speed without the danger of breaking the thread 18.

Inasmuch as the spool pins of substantially all types of sewing machines are of generally the same size the spool assembly 24 of the instant invention may be utilized on substantially all sewing machines provided with vertical spool pins mounted there atop. Further, the spindle attachment or assembly 24 requires no modifications to be made in the associated sewing machine 10 and the assembly 24 may be readily constructed in an inexpensive manner.

The foregoing is considered as illustrative only of the principles of the invention. Further, since numerous modifications and changes will readily occur to those skilled in the art, it is not desired to limit the invention to the exact construction and operation shown and described, and accordingly all suitable modifications and equivalents may be resorted to, falling within the scope of the invention.

Claims

What is claimed as new is as follows:

1. In combination with a sewing machine portion including a generally vertical spool pin projecting upwardly from an upper portion thereof, a spool rotation retarding attachment, said attachment comprising friction disk means telescoped downwardly over said pin and frictionally engaged with the latter to resist rotation of said disk means relative to said pin, said disk means including upper surface means adapted for frictional engagement with the lower end surface of a thread spool telescoped downwardly over said pin above said friction disk means, a strap including a first weighted and apertured end engaged over the upper end of said pin after a spool of thread has been telescoped downwardly over said pin on top of said disk means, the other end of said strap being anchored to said disk means and preventing a full revolution of said first end about said pin relative to said disk means, said weighted end being loosely slidable on said pin whereby the weighted end may rest, by gravity, in frictional engagement with the upper end of a spool of thread disposed on said pin.

2. The combination of claim 1 wherein said friction disk means includes upper and lower disks constructed of deformable and somewhat resilient material, spacing members disposed between diametrically opposite portions of said disks, said upper disk being at least somewhat flexible whereby the central portion of the upper disk may be displaced downwardly relative to the diametrically opposite portions thereof below which said spacing members are disposed.

3. The combination of claim 1 wherein said disks are constructed of felt material.

4. The combination of claim 1 wherein said disk means includes upper and lower portions thereof constructed of felt, said disk means having an opening formed centrally therethrough of a smaller diameter than said pin, said pin being forced through said opening with the latter sufficiently enlarged to be received over said pin with said disk means in frictional engagement with said pin.

5. The combination of claim 1 wherein said friction disk means includes upper and lower disks constructed of deformable and somewhat resilient material, spacing members disposed between diametrically opposite portions of said disks, said upper disk being at least somewhat flexible whereby the central portion of the upper disk may be displaced downwardly relative to the diametrically opposite portions thereof below which said spacing members are disposed.

6. For use in conjunction with an upright spool pin of a sewing machine, a friction disk attachment for retarding rotation of a spool or thread to be mounted on said spool pin, said attachment comprising disk means having a central opening formed therethrough of a size to receive said pin therethrough with the latter frictionally engaged with portions of said disk means defining said opening, one side of said disk means comprising an upper side and defining friction surface means for frictionally engaging the lower end of a thread spool telescoped over said pin above said disk means, a strap including a first weighted and apertured end engaged over the upper end of said pin after a spool of thread has been telescoped downwardly over said pin on top of said disk means, the other end of said strap being anchored to said disc means and preventing a full revolution of said first end about said pin relative to said disk means, said weighted end being loosely slidable on said pin whereby the weighted end may rest, by gravity, in frictional engagement with the upper end of a spool of thread disposed on said pin.

7. In combination with a sewing machine portion including a generally vertical spool pin projecting upwardly from an upper portion thereof, a spool rotation retarding attachment, said attachment comprising friction disk means telescoped downwardly over said pin and frictionally engaged with the latter to resist rotation of said disk means relative to said pin, said disk means including upper surface means adapted for frictional engagement with the lower end surface of a thread spool telescoped downwardly over said pin above said friction disk means, and a weighted apertured body portion loosely engaged over the upper end of said pin after a spool of thread has been telescoped downwardly over said pin on top of said disk means, said body portion being freely slidable on said pin for resting upon, by gravity, and frictional engagement with the upper end of said spool, and means connecting said body portion to said disk means preventing a full revolution of said body portion about said pin relative to said disk means.