US3090335A

US3090335A - Rotary hook for sewing machines

Info

Publication number: US3090335A
Application number: US41839A
Authority: US
Inventors: Bono Luigi
Original assignee: Necchi SpA
Current assignee: Necchi SpA
Priority date: 1959-07-20
Filing date: 1960-07-11
Publication date: 1963-05-21
Anticipated expiration: 1980-05-21
Also published as: DE1886388U; GB887296A; CH374532A

Description

May 21, 1963 L. BONO 3,090,335

ROTARY HOOK FOR SEWING MACHINES Filed July 11, 1960 INVENTOR. L u l6! Bouo BY M mwmwuzm A'TT DEN 5Y5 United States Patent 3,090,335 ROTARY HGDK FUR SEWING MACHINES Luigi Bono, Pavia, Italy, assignor to N ecclri Societa per Azioni, Pavia, Italy Filed July 11, 1960, Ser. No. 41,839 Claims priority, application Italy July 20, 1959 7 Claims. (Cl. 112231) The invention relates in general to new and useful improvements in rotary hooks for double-thread lockstitch sewing machines, and more particularly to novel means for connecting a bobbin case holder ring to the body of a rotary hook.

The primary object of the invention is to provide a novel means for releasably fastening a bobbin case holder ring to a rotary hook body wherein the bobbin case holder ring may be readily released or secured in place without utilizing fasteners such as screws or the like which require the use of a screwdriver or other tools.

Another object of the invention is to provide a novel connection between a bobbin case holder ring and a rotary hook body wherein the bobbin case holder ring is readily released and engaged and wherein a fastener associated with the rotary hook body and engaged with the bobbin case holder ring is utilized, the fastener being rotatable relative to both the rotary hook body and the bob bin case holder ring to release or engage the bobbin case holder ring.

Still another object of the invention is to provide a simple releasable connection between a rotary hook body and a bobbin case holder ring which employs a fastener associated with the rotary hook body and not requiring modification of the rotary hook body or the formation of openings therein.

A further object of the invention is to provide releasable connections between a drive shaft, a rotary hook body and a bobbin case with the connections employing simple contact between various components and utilizing a single screw to releasably secure the rotary hook body to the drive shaft.

The invention is characterized by a bobbin case holder ring releasably connected to a rotary hook body by a locking member disposed coaxially to the hotary hook body and rotatable about the axis of the rotary hook body while holding the bobbin case holder ring stationary to release and engage the bobbin case holder ring.

With the above, and other objects in View that will hereinafter appear, the nature of the invention will be more clearly understood by reference to the following detailed description, the appended claims and the several views illustrated in the accompanying drawing:

In the drawing:

FIGURE 1 is an elevational view of the rotary hook assembly in a normal sewing position.

FIGURE 2 is an elevational view similar to FIGURE 1, and shows the rotary hook assembly rotated to a bobbin case holder ring releasing position.

FIGURE 3 is a plan view of the rotary hook assembly of FIGURE 1.

FIGURE 4 is an exploded perspective view of the components of the rotary hook assembly.

FIGURE 5 is a fragmentary vertical sectional view through the rotary hook assembly with the bobbin case and the bobbin case holder ring omitted, and shows the details of the fastening means.

Reference is now made to the several figures of the drawing wherein the rotary hook body is referred to by the numeral 1 and the rotary thread grasping hook is referred to by the numeral 2. The usual sewing machine is provided with a small drive shaft 3 which is suitably mounted for rotation and driven in a manner not shown. The

shaft 3 has a terminal flange 3 on which the body 1 seats with the body 1 being held in place by a screw 4 passing through the body 1 and threaded into the end of the shaft 3 through the flange 3'. Relative rotation of the body 1 with respect to the shaft 3 is prevented by a pin 5 on the body 1 and engaged in a socket 6 in the flange 3'.

The rotary hook body 1 has an internal circumferential guide portion 7 which is partially closed by a bobbin case holding ring 8 to define a throat in which is seated a peripheral edge portion 9 of a bobbin case 10. The bobbin case 10 receives a customary bobbin 11.

At this time, it is pointed out that the hook 2, instead of being part of the body 1, could constitute an end of the bobbin case holder ring 8. Also, the bobbin 11, instead of being housed directly within the bobbin case 10, could be contained in a bobbin holding capsule (not shown) which, in turn, could be mounted in the bobbin case 10. This latter arrangement could be usefully employed when the hook has a horizontal axis in lieu of a vertical axis, as is shown in the drawing, without going beyond the broad concept of the invention.

The bobbin case holder ring 8 is centered with respect to the body 1 by two short depending pins 12, 12 which are received in

seats

13, 14, respectively, in the upper surface of the body 1. The pins 12, 12' also prevent rotation of the bobbin case holder ring 8 relative to the body 1.

The body 1 has a lower portion in the form of a bushing 1 on which there is mounted an elastic washer 15 and a coaxial flanged ring 16 in which the washer 15 is seated. The ring 16 is seated on the flange 3, and the washer 15 is clamped between the ring 16 and the underside of the body 1 to frictionally hold the ring 16 against rotation relative to the body 1.

The ring 16 may be rotated a limited amount around the body 1 with the rotation of the ring 16 being limited by the engagement of

upstanding ends

17, 18 thereof with ends 19, 20, respectively, of a needle protector plate 21 which is removably secured to the body 1 by means of screws 22, 23. It is to be understood that within the scope of the invention, the rotation of the ring 16 with respect to the body 1 could be accomplished by another look and slot means. The outer peripheral surface of the ring 16 may be suitably contoured, such as by knurling, to facilitate the turning thereof.

The elastic washer 15 has a plurality of circumferentially spaced fingers 24 which are seated in notdhes 25 formed in the ring 16'. In this manner, the washer 15 is interlocked with the ring 16 for rotation therewith.

The fingers 24 of the washer 15 are provided with upper inturned ends 26. The inturned ends 26 engage the bobbin case holder ring 8 to retain the same in place with the bobbin case iholder ring 8 engaging the edge portion 9 of the bobbin case 10 to hold the bobbin case in place in the body 1. The bobbin case holder ring 8 has axial outer grooves 27 of a cross-section and spacing to permit the passage of the finger ends 26. A step 27' is disposed in circumferentially adjacent relation to each of the grooves 27 for engagement by the finger ends 26 to retain the bobbin case holder ring 8 in place on the body 1. The finger ends 26 and the steps 27 are complementarily shaped to assure a perfect mutual coupling.

The elasticity of the washer 15 not only makes it possible for the finger ends 26 to move over the steps 27' and thus assure an axial load suificient to guarantee the connection of the bobbin case holder ring 8 to the body 1, but also to permit separation of the bobbin case holder ring 8 from the body 1 in the case of interpositioning of foreign elements between these parts which otherwise might rigidly block and damage the sewing machine.

From the foregoing, it is readily apparent that the releasing of the bobbin case holder ring 8 for the removal of the bobbin case is effected by the rotation of the ring 16 in a direction opposite to the direction indicated by the arrow a in- FIGURE 3 While the shaft 3 is held stationary by other components of the sewing machine. As' pointed out above, the ring 16 is knurled to facilitate the rotation thereof. After the rotation of the ring 16 has been efiected,'the finger ends 26 of the elastic Washer no longer engage the steps27', but are aligned 'with the grooves 27. The bobbin case holder ring 8 may now be removed and the bobbin case Ibis free for removal to'permit the changing of the bobbin 11.

After the bobbin case bolder ring b and bobbin case it) have been removed, the position of the ring 16 relative to the body 1, as shown in FIGURE 2, is maintained by the frictional engagement of the ring 16 with the flange 3' due to the pressure exerted by the elastic Washer 15, which frictional engagement is sufiicient to prevent relative rotation of the bobbin case holder ring 8 and the body 1. This is useful in the subsequent assembling of these parts.

When assembling the parts, the bobbincase 10 is positioned within'tlie body 1 with an appendage 28 thereof engaged in a recess 29 in a part 30 which is fastened to the base of the sewing machine. The bobbin case holder ring 8 is then mounted on the body 1 with the pins 12, i2 engaging

inthe seats

13 and 14, respectively, after which the ring 16 is rotated in the direction of the arrow a, while retaining the shaft 3 against rotation, to engage the finger ends 26 with the steps 27 and lock the bobbin ease holder ring in place.

From the foregoing, it will be seen that novel and advantageous construction has been disclosed for attaining the desired ends. However, it is to be understood that numerous variations may be made Within the scope of the invention as defined in the appended claims.

What is claimed as new:

1. In a rotary hook assembly of the type including a shaft and a rotary hook body secured to the shaft, a bobbin case seated insaid rotary book body, a bobbin case holder ring seated on said rotary book body. and retaining, said bobbin case therein, said bobbin case holder ring having circumferentially spaced seats, and a fastener connected to saidrotary hook body having fingers extending :up alongside said bobbin case holder ring and terminating in ends releasably. engaging said seats, said bobbin case holder ring having finger end receiving grooves disposed in :eircumferent-ially spaced relation to said seats, whereby said bobbin case holder ring may be released by rotating said-fastener, said fastener having a base portion resiliently clamped between said rotary hook body and said shaft.

2. In a rotary hook assembly of the type including a shaft andya rotary hook body secured to the shatt, a bobbin case seated in said rotary hook body, a bobbin case bolder ringseated on said rotary hook body and retaining said bobbin case therein, said bobbin case holder ring having circurnierentially spaced seats, and a fastener connected to said rotary hook body having fingers extending up alongside said bobbin case holder ring and terminating in ends releasably engaging said seats, said bobbin case holder ring having finger end receiving grooves disposed in circumferentially spaced relation to said seats, whereby said bobbin case holder ring may be released by rotating said fastener, and a retaining ring receiving said fastener and interlocked therewith to facilitate the rotation of said fastener.

3. In a rotary hook assembly of the type including a shaft and a rotary hook body secured to the shaft, a bobbin case seated in said rotary hook body, a bobbin case holder ring seated on said rotary hook body and retaining said bobbin case therein, said shaft having an upper end portion spaced from the underside of said rotary hook body, a cup-like retaining ring surrounding said rotary hook body and seated on said shaft end por tion, a fastener seated within said retaining ring and clamped between said retaining ring and said rotary hook body, said fastener having circumierentially spaced upstanding fingers terminating ininturned ends engaging over and retaining said bobbin holder ring in place.

4. In a rotary hook assembly of the type including a shaft and a rotary hook body secured to the shaft, a bobbin case seated in said rotary hook body, a bobbin case holder ring seated on said rotary hook body and retaining said bobbin case therein, said shaft having an upper end portion spaced from the underside of said rotary hook body, a cup-like retaining ring surrounding said rotary hook body and seated on said shaft end portion, a fastener seated Within said retaining ring and clamped between said retaining ring and said rotary hook body, said fastener having circumferentially' spaced upstanding fingers terminating in intnrned ends engaging over and retaining said bobbin case holder ring in place, said bobbin case holder ring having spaced seats and said finger ends correspond to and engage said seats.

5. The assembly of claim 4 wherein said bobbin case holder ring has finger end receiving grooves disposed in circumferentially adjacent relation to said seats, whereby said bobbin case holder ring may be released by rotating said fastener.

6. The assembly of claim 4 wherein said bobbin case holder ring has finger end receiving grooves disposed in ciroumferentially adjacent relation tosaid sea-ts, whereby said bobbin case holder ring may be released by rotating said ifiastener, said retaining ring being interlocked with said fingers to facilitate rotation of said fastener between a seat engaging position and a released position and return.

7. The assembly ofclairn 4 wherein said iiastener is of the elastic type andsaid finger ends compressively engage said seats.

References Cited in the file of this patent UNITED STATES PATENTS

Claims

1. IN A ROTARY HOOK ASSEMBLY OF THE TYPE INCLUDING A SHAFT AND A ROTARY HOOK BODY SECURED TO THE SHAFT, A BOBBIN CASE SEATED IN SAID ROTARY HOOK BODY, A BOBBIN CASE HOLDER RING SEATED ON SAID ROTARY HOOK BODY AND RETAINING SAID BOBBIN CASE THEREIN, SAID BOBBIN CASE HOLDER RING HAVING CIRCUMFERENTIALLY SPACED SEATS, AND A FASTENER CONNECTED TO SAID ROTARY HOOK BODY HAVING FINGERS EXTENDING UP ALONGSIDE SAID BOBBIN CASE HOLDER RING AND TERMINATING IN ENDS RELEASABLY ENGAGING SAID SEATS, SAID BOBBIN CASE HOLDER RING HAVING FINGER END RECEIVING GROOVED DISPOSED IN CIRCUMFERENTIALLY SPACED RELATION TO SAID SEATS, WHEREBY SAID BOBBIN CASE HOLDER RING MAY BE RELEASED BY ROTATING SAID FASTENER, SAID FASTENER HAVING A BASE PORTION AND RESILIENTLY CLAMPED BETWEEN SAID ROTARY HOOK BODY AND SAID SHAFT.