US2760024A

US2760024A - Bobbin signal

Info

Publication number: US2760024A
Application number: US365119A
Authority: US
Inventors: Tunstall Spencer
Original assignee: Individual
Current assignee: Individual
Priority date: 1953-06-30
Filing date: 1953-06-30
Publication date: 1956-08-21
Anticipated expiration: 1973-08-21

Description

Aug. 21, 1956 s. TUNSTALL 2,760,024

BOBBIN SIGNAL Filed June 30, 1953 INVENTOR. Spencer Tunstall ATTORNEY.

United States Patent BOBBIN SEGNAL Spencer Tunstall, Flushing, N. Y.

Application June 30, 1953, Serial No. 365,119

7 Claims. (Cl. 200-6115) This invention relates to bobbin signals for indicating when the bobbin in a sewing machine is approaching exhaustion.

A variety of devices for indicating when the thread on a bobbin is nearly exhausted have been proposed, utilizing feelers of various types acting against the thread on the bobbin. Such devices have, however, not been generally adaptable to sewing machines of standard types and have involved difliculties due to interference with the feeding of the thread.

It is an object of the present invention to provide a bobbin signal of a simple character which is readily adapted to use in standard sewing equipment.

Another object of the invention is to provide a bobbin signal involving a minimum of interference with the feeding of the thread.

Bobbin signals involving the invention in preferred forms will now be described with reference to the accompanying drawing, and the features forming the invention will then be pointed out in the appended claims.

In the drawing:

Figure 1 is a schematic side elevation of a sewing machine equipped with the bobbin signal of the invention;

Figure 2 is an enlarged elevational View taken on line 22 of Figure 1;

Figure 3 is a sectional View taken on line 3-3 of Figure 2;

Figure 4 is an enlarged fragmentary view showing a part of Figure 3 with the gate in a second position;

Figure 5 is a perspective view of the bobbin of Figure 3;

Figures 6, 7 and 8 are sectional views taken on lines 6-6, 7-7 and 88, respectively, of Figure 5;

Figure 9 is a perspective view of a modified form of the bobbin;

Figure 10 is a sectional view taken on line 10-10 of Figure 9; and

Figure 11 is a perspective view of the gate of the bobbin in Figure 9.

In Figure 1, there is shown a sewing machine 1 of otherwise standard or known type, to which has been added a signal light 2, and in which the bobbin and bobbin carrier assembly, indicated generally at 3, have been modified as best shown in Figures 2 and 3 of the drawing. The machine in this case is of the usual lock stitch type, in which an upper thread is fed to a needle 4 and a lower thread is supplied from a bobbin.

The showing in Figures 2, 3 and 4 is generally schematic except as to the bobbin. The sewing hook 11 is carried on the usual drive shaft 10 and has the usual cutout positioned ahead of the point 12 of the hook in the direction of rotation (clockwise in Figure 2).

A brush 14 mounted on and insulated from the hook 11 serves to make contact with the bobbin when nearing exhaustion, and a second brush 14 connected to brush 14 cooperates with a stationary contact 15 for closing a circuit to the light L. The signal light L may be supplied with power in any convenient way, as by means of a transformer T and will light when the circuit is completed from the brush 14 to the ground or machine frame in a manner disclosed below. The brush 14 is mounted to extend chordwise of the hook and diametrically 0pposite the edge 13 of the cutout, so as to prevent snagging of the thread as it leaves the bobbin.

Bobbin case carrier 16 fits in the sewing hook 11 and carries the bobbin 20. Fixed to and insulated from the carrier 16 is an annular contact ring 17. The insulating material 18 may conveniently be a liquid rubber compound which will fully insulate and is easily applied, but any satisfactory insulation may be used. The carrier 16 and bobbin case 19 are otherwise of conventional construction.

As in Figures 5 to 8, one flange of the bobbin 20 has a cutout 21, extending partway into or along the bobbin barrel, and the upper end of which is recessed or beveled as indicated at 22. Disposed on either side of the cutout 21 are aligned inner grooves 23 and outer grooves 24 spaced from one another by slots 25. These grooves receive the trunnion arms 29 of a gate or swinging contact 28. As can be seen in Figure 4, the upper or radially outward end of the gate 28 is held in the cutout 21 against the recessed ledge 22 when the thread on the bobbin 20 bears against the radially inward portion of the gate. The gate or contact 28 is spaced from the contact ring 17 by a boss or raised face 27 on the bobbin 20. When the thread nears exhaustion, as indicated in Figure 3, the gate 28 may swing on the arms 29 and engages the contact ring 17 to complete the circuit, lighting bulb L and indicating to the machine operator the lack of thread on the bobbin.

The gate 23 is preferably formed by bending a piece of spring wire to form upper and lower arms and trunnion extensions between them. The trunnion arms 29 are bent slightly as is shown in Figure 8, to give them suiiicient spring force when the arms are inserted into their respective slots to swing the upper end or arm of contact gate 28 into contact with the ring 17 when its lower end or arm is freed by the thread.

In Figures 9 through 11, there is shown a modified form of a bobbin 30 having a similar set of grooves and slots. The

grooves

23 and 24 and the slots 25 are positioned nearer the center of the bobbin. The bobbin 30 also has a cutout 31 in its other flange, this cutout being aligned axially with the cutout 21. A modified gate or contact 32 is housed in the

slots

21 and 31 and has its lower portion bent approximately from its upper or contact portion 33, forming a bell crank having a contact arm 33 and operating arm 34. When the thread (not shown) is wound on the bobbin 30, the arm 34 is held to the barrel of the bobbin and the contact or upper arm 33 is held back against the beveled edge 22 of the slot 21. The gate 32 is pivoted on the axis of the

gate trunnion arms

35 and 36, when inserted in the bobbin. The axis of arm 36 is displaced slightly from the axis of arm 35 as shown in Figure 11. The alignment of these arms when inserted in the bobbin stresses the gate 32, forcing it to swing into contact with the ring 17 when released by the thread.

What is claimed is:

1. A sewing machine bobbin comprising a barrel and flanges, a contact element for signalling approaching exhaustion of thread on the bobbin and comprising a spring wire bent to form radially inward and outward arms and trunnions extending to each side thereof, a flange of the bobbin being cut out and recessed to take the contact element and holding the same with its outward arm against a recessed outer surface of the bobbin flange and its inward arm against the thread wound thereon, the contact element being held in stressed position whereby upon exhaustion of the thread to permit movement of the inward arm, the outward arm is forced outwardly a sufficient distance to make contact with a machine element.

2. A sewing machine bobbin comprising a barrel and flanges, a contact element for signalling approaching exhaustion of thread on the bobbin and comprising a spring wire bent to form substantially coplanar radially inward and outward arms and trunnions extending to each side thereof, a flange of the bobbin being cut out and recessed to take the contact element and holding the same with its outward arm against a recessed outer surface of the bobbin flange and its inward arm against the thread wound thereon, the contact element being held in stressed position whereby upon exhaustion of the thread to permit axially inward movement of the inward arm, the outward arm is forced outwardly a suflicient distance to make contact with a machine element.

3. A sewing machine bobbin comprising a barrel and flanges, a contact element for signalling approaching exhaustion of thread on the bobbin and comprising a spring wire bent to form radially inward and outward bell crank arms and trunnions extending to each side thereof, a flange of the bobbin being cut out and recessed to take the contact element and holding the same with its outward arm against a recessed outer surface of the bobbin flange and its inward arm extending along the bobbin barrel against the thread wound thereon, the contact element being held in stressed position whereby upon exhaustion of the thread to permit movement of the inward arm, the outward arm is forced outwardly a sufiicient distance to make contact with a machine element.

4. A sewing machine bobbin comprising a barrel and flanges, a contact element for signalling approaching exhaustion of thread on the bobbin and comprising inward and outward arms and trunnions extending to each side thereof, a flange of the bobbin being cut out and recessed to take the contact element and holding the same with its outward arm against a recessed outer surface of the bobbin flange and its inward arm against the thread wound thereon, the contact element being held in stressed position whereby upon exhaustion of the thread to permit movement of the inward arm, the outward arm is forced outwardly a sufficient distance to make contact with a machine element.

5. A sewing machine bobbin according to claim 4, in which the outer arm and trunnions are held between the planes of the faces of the said flange.

6. A sewing machine bobbin having a generally radial aperture on one of its flanges and extending partway along its barrel, the flange being recessed on its outer surface at the radially outward end of the aperture to form a ledge, a contact signal element within the aperture, the radially outward end of the said element resting on the ledge and the other end extending into alignment with the barrel surface for engagement by thread thereon to hold the said outward end against the ledge, and means intermediate the said ends supporting the contact element on the flange and yieldably urging it to rotate in a direction to bring its inner end inwardly along the barrel and its outer end outwardly from the flanges.

7. A sewing machine bobbin signal comprising, in combination, a sewing hook, an aperture therein and a contact brush extending through the aperture to engage against a bobbin case carrier in the hook, the contact brush extending chordwise from a point of attachment to permit passage of a thread thereunder, a bobbin case carrier having a contact ring on its inner and outer face, insulated from the carrier and engaged by the brush, and a bobbin having a contact element, means yieldingly urging the contact element toward the said ring and means engaged by thread on the bobbin for holding the said element away from the said contact ring.

References Cited in the file of this patent UNITED STATES PATENTS 2,227,303 Flaws Dec. 31, 1940 2,420,275 Winberg May 6, 1947 2,507,078 Wright May 9, 1950