US2098269A

US2098269A - Sewing machine shuttle

Info

Publication number: US2098269A
Application number: US118845A
Authority: US
Inventors: Alfred R Wood
Original assignee: Singer Co
Current assignee: Singer Co
Priority date: 1937-01-02
Filing date: 1937-01-02
Publication date: 1937-11-09
Anticipated expiration: 1954-11-09

Description

Nov. 9, 1937, D 2,098,269

SEWING MACHINE SHUTTLE Filed Jan. 2, 1957 Alfred R Wood Patented Nov. 9, 1937 SEWING MACHINE SHUTTLE Alfred E. Wood, Bridgeport, Conn, assignor to The Singer Manufacturing Company, Elizabeth, N. J., a corporation of New Jersey Application January 2', 1937, Serial No. 118,845

2 Claims.

This invention relates to sewing machine shut-' tles, more particularly of the type comprising a circularly moving shuttle-body having an arbor on which a stationary cup-shaped bobbin-threadcase is journaled. A metallic bobbin wound with thread is customarily received within the threadcase, which latter commonly has a tubular central member constituting a bearing for the thread-case upon the arbor of the shuttle-body and further constituting an arbor for the bobbin.

Thread manufacturers furnish sewing machine users with Wound cops of thread on paper spools of approximately the same size and shape as the metallic bobbin in lieu of which they are designed to be used. These factory wound cops, however, have a tendency to swell or shrink, depending upon atmospheric conditions, and hence must be manufactured within such size limits that under no condition will they bind or drag in the sewing 0 machine thread-case but will under all conditions be free to unwind within the thread-case. As a result of this requirement, the wound paper spool or cop usually fits the thread-case more freely or with more play than the metallic bobbin, but in neither case is it practicable to fit the rims of the bobbin flanges so closely within the inner cylindrical wall of the thread-case that the bobbin-thread cannot at times escape therebetween.

When a lock-stitch sewing machine is operated at high speeds, the bobbin-thread is subjected to a rapid succession of jerks which frequently causes the bobbin to overrun and spill the bobbin-thread within the thread-case. When bobbin-thread is spilled within the thread-case it frequently escapes or leaks out of the threadcase and is fouled, caught, kinked or broken by parts of the machine. Much experimenting has been done and many devices have been made to prevent spilling of bobbin-thread within the thread-case and subsequent leakage of spilled thread therefrom. Such devices commonly comprise some sort of spring washer or friction means to be housed with the bobbin or cop within the bobbin-case for the purpose of placing a frictional drag upon such bobbin or cop. These de vices have not been successful for various reasons, chiefly because they impose a variable tension upon the bobbin-thread depending upon the amount of thread on the bobbin. The tension caused by this drag is least with a full bobbin and increases as the bobbin unwinds, becoming a maximum when the bobbin is practically exhausted. Uniform sewing cannot be done under such conditions.

The present invention aims to provide an improved sewing machine shuttle from which the bobbin-thread cannot escape under any condition and with which uniformly satisfactory sewing may be done using either wound metallic bobbins or paper clad cops.

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 drawing 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.

According to the present improvement no attempt is made to prevent spilling of bobbinthread within the thread-case, but means are provided to effectively prevent escape of the spilled thread from the thread-case.

The invention will be more fully understood by reference to the accompanying drawing, of which Fig. l is a front face elevation of a sewing machine shuttle embodying the invention. Fig. 2 is a rear face view of the shuttle. Fig. 3 is an enlarged section on the line 33, Fig. 1. Fig. 4 is a perspective View of the shuttle body from which the thread-case has been removed. Fig. 5 is a disassembled perspective view of the thread-case and cop, and Fig. 6 is a fragmentary sectional view similar to Fig. 3 but on a still further enlarged scale.

The shuttle body A of the circularly moving oscillatory type is formed as usual with a semicircular bearing rib l terminating at one end in a loop-taking beak 2. The shuttle body A is further formed with a rear wall 3 which supports the arbor 4 on which the stationary cup-shaped threadcase B is journaled.

The cup-shaped thread-case B has at its open end a circular rim 5 and an internal tubular bearing element 6 coaxial with the rim 5 and freely journaled on the arbor 4. The thread-case is adapted to receive the usual bobbin-thread spool or cop l which must be of a size such that it will not drag appreciably upon the thread-case or its bearing element 6 as the bobbin-thread 8 is being used.

The bobbin-thread 8 is drawn through the threading slot 9 and under the usual tensionspring ID from which it leads upwardly through the guide hole H in the rotation-restraining arm l2 to the work. In practice, the rotation-restraining arm l2 on the thread-case B is loosely engaged at its upper end by a notched rotation-restraining element (not shown) fixed on the sewing machine frame.

The thread-case B has the usual spring-pressed latch slide l3 which engages the shoulder 14 in 5 the arbor 4. The latch slide l3 has hinged to it at l5 a finger-operated lever l6 formed at one end with a short arm 16' which, when the lever [B is swung about the hinge I5 bears upon the fixed corner I! of the thread-case and effects re- 10 traction of the latch-slide from engagement with the shoulder l4, thus unlocking the thread-case for removal from the arbor 4. The finger-operated lever 18 has an upturned free terminal portion l6 by which it is readily engaged and opened by the operator. The broadly curvedfree edge 16 at the terminal portion of the lever 16 permits the free and easy passage of the cast needle-loop thereover as the needle loop is being drawn up in the usual manner by the sewing machine take-up (not shown). 7 g

' The shuttle-body A is formed in the inner face of its rear wall 3 with a completely circular groove l8 the diameter a of which is approximately equal to that of the rim 5 of the thread-case in juxtaposition thereto. Preferably, the rim 5 is smoothly rounded in cross-section and received in the groove l8; being clear of the walls of the latter. This construction provides a tortuous or bent clearance gap, Fig. 6, between the groove 18 '30 and rim 5 which forms an eifective seal against escape or leakage of spilled bobbin-thread, without subjecting the parts to frictional wear or requiring extreme accuracy in their manufacture. Any thread spilled within the thread-case will be used up in regular course without danger of being fouled, caught or broken by moving parts outside of the thread-case, or of being wedged between the thread-case and shuttle-body and damaged in consequence thereof.

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

1. In a sewing machine, the combination with a stationary cup-shaped bobbin-case having at its open end a circular rim and having within it a tubular bearing element coaxial with said rim, of a circularly moving shuttle-body having an arbor on which said bearing element is freely journaled and a rear wall which carries said arbor and is formed in its inner face with a completely circular groove of substantially the same diameter as-the rim of the thread-case and in juxtaposition with said rim.

2. In a sewing machine, the combination with a stationary cup-shaped bobbin-case having at its open end a circular rim and having within it a tubular bearing element coaxial with said rim, of a circularly moving shuttle-body having an arbor on which said bearing element is freely journaled and a rear wall which substantially closes the open end of said bobbin-case, there being a tortuous clearance gap between said rear wall and the rim of said bobbin-case.

ALFRED R. WOOD.