US3135086A

US3135086A - Expansible linkage

Info

Publication number: US3135086A
Application number: US163930A
Authority: US
Inventors: Shibuya Tetsuzo
Original assignee: Individual
Current assignee: Individual
Priority date: 1961-02-13
Filing date: 1961-12-28
Publication date: 1964-06-02
Anticipated expiration: 1981-06-02

Description

ne 1964 TETSUZO SHIBUYA 3,135,036

EXPANSIBLE LINKAGE Filed Dec. 28, 1961 Z'Sheet-Sheet 1 June 2, 1964 TETSUZO SHIBUYA EXPANSIBLE LINKAGE 2 Sheets-Sheet 2 Filed Dec. 28, 1961 United States Patent 3,135,086 EXPANSIBLE LINKAGE Tetsuzo Shibuya, 46 3-chon1e, Nakadori, Miyakojnna-ku,

Osaka, Japan Filed Dec. 28, 1961, Ser. No. 163,930 Claims priority, application Japan Feb. 13, 1961 1 Claim. (Cl. 59-79) This invention relates to improvements in the manufacture of expansible or extendable linkage for use in articles of jewelry such as bracelets, bands, belts and the like.

There are known pantagraph-shaped expansible linkages which comprise a plurality of pairs of links, each pair of links being pivotally connected to each other at their centers in superimposed relationship to form an X-shaped link unit and also pivotally connected to adjacent pairs of links of the same form and construction. The expansible linkages of this type are popular in the bracelets for wrist-watches. The linkage brackets with a certain number of pairs of links exert different binding forces against the various wrists of persons who wear it. In order to make a watch-bracelet so as to have a com fortable binding force for a wearer,it is necessary to control the length of the bracelet by adding or reducing the number of pairs of links composing a linkage. However, in the usual type of watch-bracelets, both ends of each pair of links are connected to the adjacent pairs of links by riveting so that aplurality of pairs of links may be locked securely against disconnection in use. This makes it diflicult to take oif a pair or pairs of links from, or add links to the linkage of the bracket.

Some attempts have been made to connect the link ele- .ments without riveting or similar mechanical operations. For example, in the UnitedStates Patent No. 2,225,746, means for pivotally connecting'the link-elements comprises openings at the ends of certain of the link-elements and hooked prongs on cooperating link-elements and the hooked prongs on certain of the elements engage through the openings in other link-elements with the hooks adapted to overlie the sides of said openings to prevent disconnection of the link-elements. In this type of linkages, however, after the parts of the linkage are once assembled the pivoted joints at the ends of the links cannot be released and it is very diflicult to take oil a pair or some pairs of link-elements from the linkage to shorten its length as desired as well as the linkages of which parts are connected by means of riveting.

The primary object of the present invention is to provide. linkages for articles ofjewelry such as bracelets, bands, belts and the like in which the above disadvantages can be avoided.

Another object of the invention is to provide expansible linkage bracelets comprising a series of pairs of links which can be easily connected and disconnected to obtain linkages of any desirable length.

A particular object of the invention is to provide improved means for pivotally connecting the link-elements with" openings at the ends of certain of the link-elements and hooked prongs on cooperating link-elements, in which .thehooked prongs can easily engage the openings in the operation for connecting link-elements to each other. A further object of the invention is to provide jointmeans for connecting pairs of links at their extremities, whereby each pair of links can be connected and disconnected only when they are put in such an unusual form of expansion and curvature as scarcely happens when they are in daily use.

A still further object of the invention is to provide the expansible linkages in which the shells whichcover the outside link-elements to embellish the completed arti lets.

cle and conceal its mechanical construction may be shaped and designed as desired.

Other objects of the present invention will be apparent from the following disclosure of typical embodiments thereof, as set forth in the accompanying drawings, wherein:

FIG. 1 is a plan view of a watch-bracelet embodying the present invention;

FIG. 2 is a greatly enlarged rear view, partly in section, of the present expansible linkage showing it contracted into closely adjacent relationship;

FIG. 3 is a further enlarged sectional view taken on line 3-3 of FIG. 2 and showing the central pivotal joint between the links and the spring means for maintaining the linkage contracted in length;

FIG. 4 is a rear view on a greatly enlarged scale, partly in section, of the linkage with its parts extended;

FIG. 5 is a rear, perspective view of two pairs of linkelements in assembled relationship of the linkage illustrated in FIG. 2;

FIG. 6 is a further enlarged sectional view on line 6--6 of FIG. 4;

FIGS. 7 and 8 are detailed sectional views similar to FIG. 6 of joint means showing two different states, in which a pair of cooperating links are bent in the direc tions, respectively indicated by the arrows;

FIG. 9 is a further enlarged sectional view of FIG. 6 illustrating the dimensional conditions of the .hooked prong and slot; 7

FIG. 10 a sectional view taken on line 1010 of FIG. 9;

FIG. 11 is a sectional view similar to FIG. 9 of another embodiment of joint means according to the invention; and

FIG. 12 is a plan view of the linkage which is connected to a wrist-watch to form a complete ring.

The invention is adapted particularly for use in the manufacture of flexible bracelets, bands, and other expansible linkages of a type now popular in watch-brace- This type of linkage comprises a plurality of articulate members pivotally connected at their centers and also pivotally joined at their extremities in X-relationship similar to the construction of the pantagraphs. The improved linkage may also consist of a plurality of elongated members of generally S-shape pivotally connected at their centers in superimposed relationship and with their opposite ends also pivotally joined so that they may be contracted into close association as shown in FIGS; 1 and 2, or extended as indicated in FIGS, 4 and -5, by rocking them on their central pivots.

When embodied in articles of jewelry, the linkage is preferably constructed with the pivotally-connected linkelements enclosed in similarly-shaped shells which may :be of precious metal or plated therewith to embellish the completed article and conceal its mechanical construction.

In the linkage construction illustrated in the drawings the mechanical pivotal elements are constructed 'in complementary pairs in the form'shown in FIG. 5, being preferably stamped out from sheet-metal. FIG. 5 shows a rear, perspective view of two pairs of link-elements in assembled relationship. Each lower link element 11 consists preferably of flat substantially S-shaped stamping having an elongated main portion with relatively straight sides and oppositely curved ends.

The element 11 is punched or perforated the the center to provide a relatively large circular opening 13 as shown in FIG. 3, while at its ends are smaller openings 14. The openings 14 are preferably shaped in the form of a slot as shown in the drawings. 1

The complementary upper link 12 which is pivoted centrally to the lower link 11 crosswise thereof is of the same general shape as the link 11, but adapted to be connected thereto in reverse underlying relationship. For this purpose the link 12 is provided at its center with an upstanding cylindrical flange forming a hollow rivet 15 adapted for insertion through the central opening 13 in the lower link 11 with its end riveted or swaged over the edge thereof, as shown in FIG. 3 so as pivotally to connect the two link-elements in overlying relationship. Each pair of link-

elements

11 and 12 are assembled and pivotally joined to adjacent pairs of link-elements of the same form and construction. In this manner a whole series of links are assembled in crossed and superimposed relationship with their ends pivotally joined to provide for extension of the linkage as a whole.

To cause the linkage to be maintained normally in contracted relationship as shown in FIG. 1, a plurality of helical springs 18 are enclosed within the cylindrical flanges or hollow rivets 15 on the elements 12 with their opposite ends extending outwardly and bearing against the sides of the

shells

19 and 20 which enclose the top and bottom of the joined link-

elements

11 and 12. The upper end 21 of each spring 18 extends outwardly in a straight arm with its end bearing against the side of the upper shell 20, while the lower arm 22 of the spring 18 is similarly directed against the side of the bottom shell 19; the springs being thus maintained under tension with their ends exerting a force against each upper and lower link-element and tending to swing them on their central pivots to bring them into substantial alignment.

The invention relates particularly to the means for pivotally connecting the outer ends of the

link elements

11 and 12. For this purpose the upper link 12 is formed at its ends with downwardly projecting prongs or lugs 16 having outwardly directed lateral projection or hooks 17 at their lower ends and the lower link 11 is provided at its ends with slots 14, the length of which is shorter than the lateral projections or hooks 17. Preferably, the prongs or lugs 16 are constructed integrally of the links in the stamping operation, but they may be made separate therefrom and suitably attached thereto.

The direction of the lateral projections or hooks 17 is aligned with the direction of the length of the slots 14 when the linkage is greatly extended to the utmost extent as shown in FIGS. 4 and 5. At this position the lateral projection or hook 17 is also aligned with the slot 14 n the straight line in the direction of the length of the linkage as shown in FIG. 4.

The hooked prong 16 and slot 14 as joint means according to the invention are preferably shaped under the following dimensional conditions as illustrated in FIGS. 9 and 10: the length of the slot 14, a is smaller than b, the length of the lateral projection 17 of the prong 16 but larger than c, the diameter of the prong 16; the width of the slot 14, d is larger than c, the diameter of the prong 16; in addition the diagonal width of the lateral projection 17 at its root, e is smaller than a, the length of the slot 14 but larger than d, the width of the slot 14.

So far as the above conditions are satisfied, both the shape and dimension of the prong and slot may be designed at will. For example, the prong may be shaped in its lateral section in any form of a circle, an ellipse, an egg-shape and a Wedge-shape and the shape of the slot may depend on the sectional form of the prong. It is also possible to carry out the invention in such a manner as illustrated in FIG. 11 in which the hooked prong is substantially T-shaped and is provided with a lateral portion extending in opposite directions outwardly and inwardly. The corresponding members and dimensions are indicated with the same reference numerals and symbols as in FIG. 9.

Each pair of link-

elements

11 and 12 assembled in an X-s'haped link unit are joined at their ends to other pairs of links of similar construction and arrangement by first extending the two pairs of connected

elements

11 and 12 until the projection or hook 17 and the slot 14 of one pair are aligned in the direction of the length of the link age with the slot 14 and the projection or hook 17 of the other pair, respectively, and then inserting the projections or hooks 17 into the respective slots 14 through the state as shown in FIG. 7. The lugs 16 are thus positioned in the slots 14 for pivotally connecting the ends of the links. A whole series of pairs of links are joined together in this manner to provide a linkage of any desired length.

The two pairs'of link-elements thus connected are also detachable from each other only when they are extremely extended as shown in FIGS. 4 and 5, in which the lateral projection or hook 17 and the slot 14 of one pair are aligned with the slot 14 and the projection or hook 17 of the other pair in the direction of the length of the linkage. At any other contracted or half extended positions in which the projection or hook 17 and slot 14 of one pair are not aligned with the slot 14 and the projection or hook 17 of the other pair, these two pairs of link-elements can be neither connected to, nor disconnected from each other because the hooked prong 16 is provided with an expanded portion, namely the diagonal diameter of the lateral projection 17 at its root in the direction normal to the axis of the prong 16 is larger than the width of the slot. At the fully extended state as shown in FIGS. 4 and 5, the adjoining two pairs of link-elements are not yet ready to detach from each other because each lateral projection or hook 17 is longer than the length of the slot 14 and they are still in the state of a perfect engagement. Actual disconnection of the two pairs of link-elements can be carried out by tilting one of the pairs of connected elements with respect to the other pair in the direction indicated by the arrow in FIG. 7. The lug 16 followed by the lateral projection 17 then passes aslant through the slot 14 to be detached from it. On the contrary, if a bending moment is given between the connected elements in the opposite direction, that is, in the direction of the arrow shown in FIG. 8, the lateral projection 17 collides against the lower surface of the link-element 11 or the shell 19. When the linkage constructed as above is used, for example, for a watch-bracelet, the linkage is so connected to a wrist-watch to form a complete ring as to put the link-element 12 having the lugs 16 outside and the link-elements 11 having slots 14 inside as shown in FIG. 12, whereby such a bending moment as shown in FIG. 7 scarcely happens in ordinary use.

The joint means according to the invention is advantageous in that the end of the lateral projection 17 can easily engage in the slot 14 in the operation for connecting link-

elements

11 and 12 to each other since both the lateral projection 17 and slot 14 are visible, the lateral projection being outwardly directed. In addition the linkage according to the invention has the advantage that the form of the shell 20 of the outside link-element 12 may be designed more freely than in any other linkages of known type. For example the shell 20 may not only be shaped with a gentle slope as shown in FIGS. 6 to 9 and 11 but also cover the outside link-element 12 in directly and closely superimposed relationship, because there is no projection on the upper surface of the outside link-element 12.

While the device is herein shown asernbodied in a preferred form of construction, it is to be understood that various modifications may be made in the structure and arrangement of its parts without departing from the spirit or scope of the invention.

What I claim is:

In an expansible linkage for articles of jewelry such as bracelets, bands, belts and the like, the combination of a plurality of pairs of link-elements, each pair of linkelements consisting of an outer and an inner link-element pivotally connected to each other at their centers in superimposed relationship to form an X-shaped link unit, with means for pivotally connecting each pair of link-elements to adjacent pairs of link-elements of the same form and and aligned with said slots only when said linkage is in 10 an extremely extended position, and wherein said hooked prongs are provided with an expanded portion at the roots of said lateral hooks thereon, said expanded portion having a diagonal diameter greater than the width of said slots but less than the length of said slots, whereby said adjacent pairs of link-elements may be disengaged only by tilting the outer link-element away from the inner link-element when said link-elements are in an extremely 5 extended position.

References Cited in the file of this patent UNITED STATES PATENTS 2,225,745 Kestenman Dec. 24, 1940 FOREIGN PATENTS 548,231 Italy Sept. 20, 1956 324,396 Switzerland Sept. 15, 1957