US2986871A

US2986871A - Telescopic expansible linkage having transversely positioned coil springs

Info

Publication number: US2986871A
Application number: US860169A
Authority: US
Inventors: Karl C Augenstein
Original assignee: SPEIDEL CORP
Current assignee: SPEIDEL Corp
Priority date: 1959-12-17
Filing date: 1959-12-17
Publication date: 1961-06-06
Anticipated expiration: 1978-06-06

Description

June 6, 1961 K. c. AUGENSTEIN 2,986,871 TELEscoPIc EXPANSIBLE LINKAGE HAVING TRANsvERsELY PosITIoNED coIL SPRINGS Filed Dec. 1'?, 195s 3 Sheets-Sheet 1 ATTORNEYS June 6, 1961 K. c. AUGr-:NSTEIN 2,985,871

IELEscoPIc ExPANsIBLE IINKAGE HAVING TRANsvERsELY PosITIoNEn coIL SPRINGS Filed Dec. 17, 1959 5 Sheets-Sheet 2 F I G. 6 INVENToR.

KARL c. AUGENSTElN BY ocW/zaamm ATTORNEYS 2,986,871 SELY June 6, 1961 K. c. AuGENsTElN TELEscoPIc EXPANSIBLE LINKAGE HAVING TRANsvER POSITIONED COIL SPRINGS 3 Sheets-Sheet 3 Filed Dec. 17, 1959 INVENTOR. KARL o. AUGENSTEIN' BY @@Mycgwmam/ZZM ATTORNEYS States Island Filed Dec. 17, 1959, Ser. No. 860,169 l Claims. (Cl. 59-79) The present invention relates to an improved link construction for an expansible, self-retracting band of links comprising outer hollow links and inner links telescopically received therein, such bands being suitable for use as Wrist watch bands, bracelets, or the like. This application is a continuation-impart of U.S. application Serial No. 817,271 filed June l, 1959.

An object of the present invention is to provide an improved link construction for such a band which is simple but rugged, which will last a long time with a minimum of repair and which can be expanded to relatively long lengths per unit of retracted length so :that the band can be used in a large variety of wrist sizes.

A further object is to provide such a link construction which is simple and inexpensive to manufacture.

Another object is to provide a link construction which employs a coil spring in the outer link with the central axis of its coil located generally perpendicular to the plane of the link. One end of the spring is anchored to the outer link and the other acts on and is movable with the inner link to wind the spring .when the inner link is telescopically moved out of the outer link.

By using two coil springs the thickness of the strands and the height of the coils may be reduced so that they occupy less vertical height. This involves the use of two inner links in each outer link, each spring acting between the outer link and one of its inner links. One spring and its inner link occupy one end portion of the outer link and the other spring and its inner link occupy the other end portion.

Preferably, each link is located above or below one end of each of the coils between such end and a slotted upper or lower wall of the outer link having a pair of elongated slots into which the ends of the springs acting on the inner links are received. The slots are located on opposite sides of the longitudinal centerline of the band and extend from the mid portion of the outer link towards opposite ends of the outer link. The ends of the springs engage the inner links so that movement of the inner links in opposite directions out of the opposite ends of the outer link moves such ends of the springs in such opposite directions and in their slots from a mid portion of the outer link towards the opposite ends thereof to wind the springs. However, the inner links may, if desired, be located on the side of the slotted wall opposite from the springs.

The two inner links telescopically received within adjacent ends of adjacent outer links are separably and pivotally connected together by means of connecting links. The inner links are thin in vertical dimension so as to occupy a minimum of vertical space.

Further objects and advantages of the present invention will become apparent from a consideration of the following description and accompanying drawings, in which:

FIG. 1 is an enlarged top plan view of an embodiment of the present invention with the links in retracted positions and with portions cut away.

FIG. 2 is a view like FIG. 1 with the links in expanded positions.

FIG. 3 is a section taken lalong the line 3-3 of FIG. 1 but showing the cut away portions of FIG. l.

FIG. 4 is a section taken along line 4 4 of FIG. 2 but showing the cut away portions of FIG. 2.

FIG. 5 is a section taken along line 5-5 of FIG. 3.

atent i 2,986,371 Patented June 6, 1961 FIG. 6 is a section taken along the line 6 6 of FIG. 3 with a portion of a spring cutaway.

FIG. 7 is a section taken along the line 7-7 of FIG. 3.

FIG. 8 is an exploded view in perspective of the parts of an outer link of the band of FIG. l, a pair of inner links and two coil springs.

FIG. 9 is a top plan view of a spacer connecting link (modification of the connecting link of FIGS. 1 to 4) for pivotally connecting the inner links of adjacent outer links and interchangeable with the connecting link structure of FIGS. l lto 4 to increase the retracted length of the band.

FIG. l0 -is `a section taken `along the line 10-10 of FIG. 9.

FIG. 11 is a section taken along the line ll-Il of FIG. l0.

With reference to the gures, 2 represents a band of telescopical links comprising a plurality of hollow outer links 4 laid end to end, each of which outer links has a pair of inner skeleton links 6 telescopically received within the opposite ends thereof, the inner links 6 telescopically received within adjacent ends of adjacent outer links 4 being pivotally connected by means of connecting links 8.

Each inner skeleton link comprises a pair of spaced crossbars 7 which extend in a direction transversely to the longitudinal center line of the band, which are very thin in width (direction of the longitudinal center line of the band) and which are connected by a pair of spaced interconnecting side bars 9 extending in a direction generally parallel to the longitudinal center line of the band. Side bars 9 are wider than the crossbars 7. The bars are thin in vertical height but not so thin as to reduce the strength of the link beyond a safe point. A tab 11 extends inwardly from the mid-portion of the inner `edge 55 of the inner crossbar 7 of each inner link 6.

Each hollow outer link 4 has a slight curvature in the direction of the longitudinal center line of the band so that it will iit the contour of the wrist (the inner links 6 have a corresponding curvature) and comprises a lower, channular-shaped base member 10 (see FIGS. 3 to 6 and 8) open at the top, an upper inverted, channular-shaped cover member 12 located over base member 10 and forming therewith a compartment 14 (FIGS. 3 to 6) in which is located a pair of cylindrical coil springs 16 and a pair of inner links 6 located above the springs, and an ornamental shell 18 comprising a frame member 20 and a leather strip 22 mounted on a backing plate 24 and framed by the frame member 20.

The lower channular-shaped base member 10 has a bottom wall 26 which has a centrally dished out or recessed portion 28 extending along the longitudinal length thereof, whereby such wall is provided with narrow raised side portions 30 extending along the sides thereof.

The side edges of bottom wall 26 extend upwardly into side walls 31.

'Ihe opposite end edges of the bottom wall 26 are provided with centrally located recesses 32 (see FIG. 8). Recesses 32 extend along the Width of the dished or recessed portion 28 of the bottom wall 26, but do not extend along the end edges of side portions 30, whereby the end portions of such side portions are in the form of 1ongitudinally extending narrow strips 34.

The transverse edges of the recesses 32 extend upwardly into end walls 36 (FIG. 8). Strips 34 extend longitudinally beyond such end walls 36. The opposite side edges 37 of each end wall 36 are spaced from side walls 31 to form openings 38 at either side of each of the end walls 36 for slidably receiving the side bars 9 of the inner links 6, as shown. The mid-portion of the upper edge of each of the end walls 36 has a recess 40 therein for receiving the tabs 11 of inner links 6 when the band is fully expanded as shown in FIGS. 2 and 4. The upper edge of part 35 of each end wall 36 at one side of recess 40 is stepped at 42 to provide a wall portion 44 adjacent recess 40 which is higher than portion 46 adjacent side opening 3 8. Portion 46 is bent slightly inwardly from portion 44 as shown. The part 39 oi the end wall 346 at the other side of recess 40 yis about the same height as 46 but the portion thereof adjacent the other side opening 38 is bent inwardly at 4S at about a 90 degree angle, as shown in FIGS. l, 2, 6, and 8. Portion 48 is bent by slitting the wall 39 vertically and then bending it. It is noted that part 35 ,of one of the end walls and part 39 of the other end wall are located on one side of the longitudinal center line of the linkage whereas part 3-9 of such one end wall and part 35 of the other end wall are located on the other side of the longitudinal center line of the linkage.

The floor of the dished portion 28 immediately adjacent and inwardly of part 39 of each end wall 36 is struck upwardly at 50 to provide a loop 50 the opening of which extends in a direction from side to side of the link and a wall of which is formed by 39.

Each loop 50 and its adjacent bent-over portion 48 anchor the lower end of a coil spring 16 to the floor of dished out portion 28 with the central axis of the coil of the spring located generally perpendicular to the plane of the linkage, as shown in FIG. A8. The springs each have 3 coils and are located side by side in the dished out portion 28. They are centrally disposed in portion 28 with respect to the sides of 26 so that the central axes of the coils of both springs fall on or in close proximity to the longitudinal center line of the band. The coils are spaced from the sides of dished portion 28. The lower coil of each spring rests on the floor of dished out portion 2S and the end of such lower coil is received in a loop 50 and after extending through the loop is bent upwardly at 52 along the inner surface of part 39 of end wall 36. The lower end of one spring extends through its loop from its coil toward one side of the link whereas the lower end of the coil of the other spring extends through its loop from its c oil towards the opposite side of the link.

Tabs 48 prevent the end portions 52 of the springs from moving laterally into side openings 38. The loops 50 are located so that they do not interfere with telescopical movement of the inner links in openings 38 and so that they anchor the springs in positions which do not interfere with such movement.

Note that the two loops 50 and hence the anchored ends 52 of the two springs are on opposite sides of the longitudinal center line of the linkage and are located at opposite ends of the link.

The other end 54 of each spring 16 extends from the upper end coil at a tangent to the coil at 54a and then upwardly in a direction generally perpendicular to the plane of the coil to engage a side portion of the inner edge 55 of the inner crossbar 7 of an inner link 6 and is then bent over such inner crossbar 7 at S6, as shown in FIGS. l to 5 and 8.

The springs are partially compressed or wound when the bracelet is in retracted position as shown in FIG. 1 to urge the inner links 6 in opposite directions toward each other and into the opposite ends of the outer link 4 and the outer edges of the inner crossbars 7 of the two inner links into engagement with each other, as shown in FIG. 1. In this condition the two inner crossbars 7 are located at the mid portion of the outer link with respect to the ends thereof and abut against each other along a plane which bisects the outer link.

The end portions 54-56 of the two springs 16 are located at opposite sides of the longitudinal center line of the linkage, each end portion 54-56 being located on the same side of such center line as its anchored end 52 and between tab 11 of its inner link and the side bar 9 of `the inner link on such side of the center line. Partial compression and hence partial winding of the spring forces the end 54-56 toward such side of the link until it engages the side bar 9 as shown in FIG. 1 so that such end portion 54-56 is located in and engages the corner formed by the inner edge 5S of its inner crossbar 7 and the inner edge of the side bar as shown in FIG. l.

The tabs 11 aid in assembling the linkage and overlie p arts of the coils of the springs to prevent the inner crossbars 7 from Adropping below the tops of the coils and from becoming caught between or entering between the coils. They also insure against the end portions 54-56 of the springs moving from the sides of the links which they occupy in the `drawings beyond the longitudinal center line of the linkage to the other sides, although ordinarily the spring tension of the springs prevents this.

The end portion 54-56 of each spring is received in an elongated slot 58 in the top wall 60 of the cover member 12 located over the open top of base member 10.

The mid portions of the end edges of cover member 12 are recessed at 62 like the end edges of Ythe bottom wall 28 of the base member, whereby the side portions at the opposite ends of top wall 60 form narrow strips 64 which overlie strips 34 of the bottom wall 26 and are about the s ame width and length as strips 34. Recesses 62 overlie recesses 32 of bottom Wall 26. About one half of the transverse edges of recesses 62 are counter-recessed slightly at 63, the counter-recess ,63 in one transverse edge being on one side of the longitudinal center line of the linkage and the counter-recess 63 in the other transverse edge being on the other side of such center line. The counter-recesses 63 form shoulders 64 which are located on or about the longitudinal center line of the linkage.

Cover member 12 has a pair of depending side walls 65 the lower portions of the ends of which are recessed at 66. Sidewalls 65 extend downwardly and snugly over the outside `of sidewalls 31 of the base member 10 and are turned inwardly at 66a (FIGS. S, 6 and 8) under the raised side portions 30 of the base member, as shown, to secure vthe cover member to the base member. The engagement of the tops of the sidewalls 31 of the base member 10 with the top wall 60 of the cover member 12 spaces the top wall 60 above wall 26 of the base member to provide adequate room for the springs 16 and inner links 6 so that the inner links `are freely slidable between top wall 60 and the top ends of the coils of the springs and between top wall 60 andthe raised side portions 30 of bottom wall 26 without binding and so that the end portions 54-56 of the springs extend into the slots 58 of the top wall 60 when the bottom coils of the springs rest on the floor of the recessed midportion 28 of the base member. It is noted that each inner link 6 is located above the top end of the coil of its spring between such end of the coil and the slotted wall 60 of the cover member with the opening of the link formed by the

bars

7 and 9 axially aligned with the coil and with the plane of the inner link generally perpendicular to the central axis of the coil.

The tops of portions 44 of the end Walls 36 of base member 10 extend upwardly opposite and closely adjacent the edges 63 of top wall 60 to prevent relative movement between the base member 10 and cover member 12 in a direction parallel to the longitudinal center line of the band, The steps 42 in the upper edges of walls 35 of base member `10 lie laterally opposite the shoulders 64 of top wall 60 to prevent relative lateral movement between the end portions of the two

members

10 and 12. The tops of

portions

39 and 46 of the end walls 36 extend to just below the transverse edge portions of the recesses 62 in the top wall 60. Portions l46 are bent slightly inwardly under the edges 63 ofthe top wall as shown. The tops of portions 39 of end walls 36 lie under the non counter-recessed portions of the transverse edges of recesses 62 in the top member. Thus the end walls 36 close the ends of the hollow links except for openings 38 at the sides thereof which slidably receive side bars 9 of the inner links.

The heights of the coils of springs 16 are slightly greater than the depth of the dished Vout portion 2 8 ofthe bottom wall of base member so that the coils extend slightly above the raised side portions 30.

The side bars 9 are located and slide in the marginal spaces between the raised side portions 30 of the base member 10, the side portions of top wall 60 located over 30 and the side walls 31 of the base member. The side edges of the inner links 6 it snugly between the side walls 31 but loose enough for the links to be freely slidable. The only portions of the inner links which are located directly over the coils are the inner cross bars 7 and their tabs 11. Such inner cross bars and the raised side portions 30 of the base member prevent the inner links from moving downwardly around the coils. The height of the above mentioned marginal spaces is greater than the height or thickness of side bars 9. Springs 16 hold the inner links in the upper parts of the spaces. The springs should not be so high as to cause the inner links to be urged so tightly against the top wall 60 so as to cause binding between the inner links and the coils between the inner links and wall 60 or between the coils. 'Ihe side bars 9 do not extend inwardly over the coils and the outer cross bars 7 are not located over the coils.

The slots 58 (FIGS. 1, 2, and 8) lie on opposite sides of the longitudinal center line of the linkage and extend from the mid-portion of the top wall 60 in opposite directions toward the opposite ends of the top wall. 'I'hey terminate at outer ends 68 closely adjacent the noncounter-recessed transverse edges of recesses 62. The outer ends 68 of the slots are generally aligned with the counter-recessed transverse edges 63 of the recesses 62. Each slot is relatively wide at its inner end 70 and is narrower at its outer end 68. The inner, wide ends overlap each other slightly so that the inner abutting cross bars 7 of the inner links are exposed by both slots when the band is retracted as shown in FIG. 1.

The inner side edge 72 of each slot extends from the wide end 70 diagonally at 74 toward an end and side of wall 60 (each edge 72 extending toward an opposite end and side) and then turns in a direction more nearly parallel to the longitudinal center line of the band at 76.

The outer side edge 78 of each slot extends from wide end 70 toward the end of the wall 60 at `a very slight angle to the longitudinal center line of the band. The side bars 9 extend beyond the outer side edges 78 of the slots sufciently so that the upper end portions 56 of the springs do not engage the side edges 78 of the slots when they are rotated to the positions shown in FIG. 2 in which the band is fully expanded, from the positions shown in FIG. l in which the band is fully retracted. Thus the end portions 54-56 of the springs do not engage the slots except the narrow, inner ends 68 thereof when the band is fully expanded `as shown in FIG. 2.

It is apparent that when the band is expanded to move the two inner links 6 out of the opposite ends of the outer link 4, the inner cross bars 7 are moved over the tops of their springs and the upper end portions 54-56 of the springs are moved along the slots 58 in opposite directions from the mid-portion of the outer link toward the opposite ends of the outer link to thereby wind the springs. This movement of the inner links is limited by engagement of the inner edges 55 of the inner links 6 against the upstanding end portions 52 of the springs and by engagement of the end portions 54-56 of the springs with the narrow ends 68 of the slots 58 as shown in FIG. 2. In this fully expanded position of the band, the end portion 54-56 of each spring is located along side and outside of its upstanding end portion 52 and the tabs 11 are received in the recesses 40 in the end walls 36. In this way maximum expansion is possible. Note in FIG 2 how the individual coils of the unconned coil cylinder of each spring are displaced toward the corner of the outer link formed by the end wall toward which end 54-56 of the spring is moved and the side wall of the link opposite from the side on which the ends 5456l and 52 are located when the band is expanded, each individual coil being so displaced with respect to the coil under it. This is due to the fact that the end 54-56 tends to move in an arc about the central axis of its coil and toward a side of the outer link as it -is wound. Since engagement of 54-56 with side bar 9 prevents this movement, the coils are forced toward the opposite side of the outer link. At the same time the coils are moved in a direction toward the end wall by movement of 54-56 in such direction so that the result is diagonal displacement, the coils closest to end 54--56 to which the forces are applied being displaced the furthest. End portions 52 of the springs are urged laterally inwardly against the outer edges of the loops 50. yUpon release of the expansion forces the springs return the inner links to the positions shown in FIG. 1 in which the inner cross bars 7 are urged into abutting relationship with each other at the middle of the outer link. The individual coils of each coil cylinder are still displaced slightly toward the adjacent end wall and the side of the outer link and with respect to each other due to the partial compression thereof.

Springs 16 may be spiral springs or may have conicalshaped coils.

The top wall of frame 20 of ornamental shell 18 comprises a frame ange which frames leather strip 22 attached to the top of backing plate 24 by means of pointed prongs 82 (see FIGS. 4 and 5) extending upwardly along the edges of the backing plate into marginal portions of the leather strip. The opposite ends of the leather strip 22, backing plate 24 and flange 80 are centrally recessed at 84 and `86 respectively (see FIG. 8) in substantially the same way as the bottom wall 26 of base member 10 and top wall 60 of cover member 12, whereby the ends of the side portions thereof are in the form of narrow strips overlying the

narrow strips

34 and 64 of the base member 10 and cover base member 10 and cover member 12, respectively, as shown. 'Ihe recesses 84 and 86 are vertically aligned with the recesses 32 and 62 in the base member and cover member. The recess 84, however, has a counter-recess 85 of curvilinear shape. The ornamental shell is attached to the top of the outer link assembly by means of tabs 88 extending from depending side walls 90 of the frame member under raised portions 30 of the base member 10 as shown. These tabs extend along the recesses 66 in side walls 65 of the cover member so that the tabs are located under the raised portions 30 along side the inturned anges 66a of the side walls 65 of the cover member. Side walls 90 of the ornamental shell extend downwardly along the outside of the side walls 65.

The opposite ends of frame flange 80 extend downwardly into end walls 92. The center portions of end walls 92, which extend from the transverse edges of recesses 86, overlap slightly with the top portions of end walls 36 of the base member, as shown in FIG. 3, and have recesses 93 in the center portions thereof which are aligned with recesses y40 of end walls 36 and which cooperate with recesses 40 to form center openings in the end walls of the outer link for receiving the tabs 11. The side portions '94 of end walls 92 extend over the ends of the narrow side strips 64 of the cover member 12 and over the ends of the corresponding narrow side strips of the leather 22 and backing plate 24.

The backing plate 24 bulges upwardly to provide a space above the top wall 60 so that the backing plate does not interfere with movement of the ends 54-56 of the springs.

When the band is retracted the outer transverse edges of the outer cross bars 7 adjacent the ends of the hollow outer link 4 are approximately aligned with the ends of the side walls 31 of the base member as shown in FIG. 1. These outer cross bars 7 of the inner links 6 extending out of adjacent ends of adjacent outer links are pivotally received in a hollow tubular connecting link 8 comprising an inner tubular member 100 (FIG. 3) having a top wall 102, a pair of end walls 103 and a bottom wall comprising inwardly turned flanges 104 extending from the bottom edges of the end walls and the edges of which are spaced from each other, as shown in FIG. 3. Member 100 is open at its sides. The middle portions of the edges of flanges 104 have tabs 106 (see FIG. 7) extending slightly downwardly with respect to the rest of the anges.

The inner tubular member 100 is enclosed in an outer ornamental hollow shell 108 having a top decorative wall 110 located over the top wall of member 10i), a pair of end walls 112 (FIG. 4) depending along the outside of end walls 103 of the inner member 100 and a bottom wall comprising inwardly turned anges 114 extending from the bottom edges of the end walls 112 with the edges of the anges spaced from each other about the same distance that the edges of anges 104 are spaced from each other. Outer shell 108 has a pair of short side walls 116 (see FIG. 7) extending downwardly from the side edges of the top wall thereof over the side edges of the top wall 100 of the inner member.

An elongated insert plate 118 having a thick central portion 120 and thinner side portions or flanges 122 is provided to close the openings between the edges of

flanges

104 and 114, as shown, the side portions or ilanges 122 of the insert plate being wedged between the

flanges

104 and 114, as shown, and having recesses 124 located centrally of the ends thereof, which recesses receive the tabs 106 to form detents for preventing the insert plate from sliding sideways out from between the flanges of the inner member and the outer ornamental shell. However, by exerting a force on a side edge of the insert plate sufiicent to overcome the spring force of the tabs 106 to bend them out of the recesses 124, the insert plate can be forced in a sideways direction with respect to the inner and outer shells completely out from between the flanges of `the outer shell and the inner shell.

The distance between the opposed edges of the flanges of the inner shell and outer shell is great enough so that the cross bars 7 can be moved through the spaces between such opposed edges of the anges out of the connecting link when the insert plate is removed. In this way, the length of the band can be decreased or increased by removing or adding sets of links, each set of links comprising a hollow outer link and a pair of inner links telescopically received therein. When the insert plate is reinserted, it is forced sideways between the anges of the inner and outer shells until the tabs 106 snap into the recesses 124 to lock the insert in place.

It is noted in FIG. l that when the links are in retracted position each connecting link 8 is located in an opening 126 between adjacent hollow outer links 4 and formed by opposed recesses in the opposed edges of the various parts of the adjacent hollow outer links. This arrangement increases the total expansion of the band per unit of retracted length because it permits the ends of the marginal side portions of the outer hollow links to abut against each other at 128 and the connecting links 8 do not increase the retracted length of the bracelets by the sum of the widths thereof in the direction of the longitudinal center line of the band which would be true if it were not for such recesses. Also, by making the dimensions of the cross bars 7 in the direction of the center line of the band thin, maximum expansibility per unit of retracted length is obtained. The only substantial space in the hollow outer links which is not available for expansion is the space occupied by the abutting cross bars 7 when the band is retracted.

If it is desired to increase the retracted length of the band by less than the length in the longitudinal direction of a set of links or by an amount which is less or more than a multiple of the length of such set, one or more of the connecting links l8 can be easily replaced by the jeweler by the spacer link 210 shown in FIGS. 9 to 11.

The spacer link comprises a main outer spacer shell 212 having a top ornamental wall 214 which is wider in the direction of the longitudinal center line of the band than the top wall of connecting link 8. Shell 212 has the same dimension in the direction transverse to the longitudinal center line of the band as the hollow outer link 4. The top wall 214 has recesses 216 in the corners thereof to form a wide middle portion 218 which lits within opposed recesses 126 in the adjacent ends of adjacent outer links 4 when the bracelet is retracted and narrow portions 220 which t between the side portions of the end edges of adjacent outer links, as shown in FIG. 9.

Shell 212 has a pair of downwardly extending walls 222 which are curled inwardly (see FIG. 10) to form hinges for receiving the cross bars 7 of the inner links extending from adjacent ends of adjacent outer links. Shell 212 has a pair of side walls 224 (FIG. ll) extending downwardly from the top wall thereof, the lower ends of such walls 224 being turned slightly inwardly to form a spring clip to resiliently clip in the shell 212 an inner member 226 having upwardly extending side walls 226a extending upwardly along the inside of the side walls 224 and under which the inturned spring end portions of said side walls 224 extend to hold the inner member or shell in the outer shell as shown.

The inner member has a pair of upwardly extending end walls 228 which form with the downwardly extending walls 222 of the outer shell, the hinges for the cross bars 7, as shown in FIG. l0.

The spacer link can be removed by forcing the inner shell downwardly out of the outer shell against the force of the spring clip formed by the walls 224, whereupon the cross bars 7 can be removed. It is installed by reversing such steps.

Since the spacer link is wider in the direction of the longitudinal center line of the bands than connecting link 8, it prevents the two adjacent sets of links from completely retracting and hence the retracted length of the band is increased.

While several embodiments of the invention have been shown and described, it will be understood that many changes and modifications may be made therein without departing from the spirit and scope of the invention as defined in the appended claims.

I claim:

l. In an expansible, self-retracting band of links, a hollow outer link and a slidable inner link telescopically received therein for longitudinal movement with respect thereto, said outer link having a coil spring located therein with the central axis of the coil thereof generally perpendicular to the plane of the link, said spring acting between said inner link and a portion of said outer link to resiliently resist telescopical longitudinal movement of said inner link out of said outer link, one end of said Spring being anchored to said outer link, the other end of said spring acting on and being movable with said inner link to wind said spring, said inner link overlying the coil adjacent said other end of said spring and extending in a direction generally perpendicular to the central axis of the coil, said telescopical longitudinal movement of said inner link being in a direction generally perpendicular to said central axis, said other end of said spring extending outwardly from the coil of said spring in a direction generally parallel to the central axis of the coil and engaging said inner link, said spring being located in a compartment in said outer link having a top wall, an opposite bottom wall and a pair of side walls, the top wall lying adjacent to one end of said coil and the bottom wall lying adjacent to the other end of said coil, the wall of said compartment lying adjacent the end of said coil from which said other end of said spring extends having an elongated slot receiving said other end of said spring, said other end of said spring being moved along said slot during winding thereof by expansion of the band.

2. A band according to claim 1, said spring being partially compressed when the bracelet is contracted.

3. A band according to claim 2, said inner link being located in said compartment between said end of said coil from which said other end of said spring extends, and said slotted wall.

4. A band according to claim 2, the wall of said outer link opposite said slotted wall being recessed intermediate the opposite sides thereof, said spring being located in said recess, said recess being spaced from said opposite sides to provide raised opposite side margins, said inner link comprising a pair of opposite cross bars extending in a direction from side to side of the band and a pair of opposite side bars extending in a direction generally parallel to the longitudinal center line of the band, said bars forming a central opening axially aligned with the coil of said spring, said side bars being vertically disposed with respect to said side margins, said other end of said spring engaging the inner edge of one of said crossbars to urge the inner link into said outer link.

5. A band according to claim 4, said side bars being slidably received in the marginal side spaces between said raised side margins and said slotted wall.

6. A band according to claim 5, said other end of said spring being bent over said crossbar which it engages.

7. A band according to claim 5, said slot being located at one side of the longitudinal center line of said linkage and extending in a direction from end to end of said band, said spring comprising a cylindrical coil spring, said cross bar engaged by said other end of said spring having a tab extending from the mid portion of the inner edge thereof over said coil of said spring, said other end of said spring being located between said tab and the side bar located on the same side of said longitudinal center line as said slot.

8. A band according to claim 7, said inner link being received in an end of said outer link, said outer link having an end wall to prevent said inner link from moving completely out of the end of said outer link in which it is received, the mid portion of said end wall having an opening for receiving said tab when the band is expanded to its maximum length, the side portions of said end wall having openings for slidably receiving said inner link, said last mentioned side openings registering with said marginal spaces between said raised side margins and said slotted wall.

9. A band according to claim 8, including means for anchoring said one end of said spring to a portion of the iloor of said recess directly adjacent to and Within said end wall between said middle opening and a side opening thereof, said other end of said spring being located at the mid portion of said outer link with respect to the ends thereof when the band is retracted and when the band is fully expanded being located at the end portion of said outer link at which said one end of said spring is located.

lO. A band according to claim 2, said slot being located at one side of the longitudinal center line of the band and extending from a mid portion of said slotted wall with respect to the ends thereof toward an end thereof, the inner side of said slot extending from a mid portion of said slotted wall with respect to the ends thereof at a point offset from the longitudinal center line of said band and spaced laterally from the side of said slotted wall, in a direction toward said end and side of said slotted wall.

1l. In an expansible, self-retracting band of links, a hollow outer link, an inner link telescopically received within said outer link and movable longitudinally into and out of one end of said outer link, a coil spring located in said outer link with its central axis generally perpendicular to the plane of the link, said spring acting between said inner link and a portion of said outer link to resiliently resist said longitudinal movement of said inner link out of said outer link, a second inner link telescopically received within said outer link and movable longitudinally into and out of the end of said outer link opposite said one end, a second coil spring located within said outer link with its central axis generally perpendicular to the plane of the link, said second spring acting between said outer link and said second inner link to resiliently resist telescopical longitudinal movement of said second link out of said other end of said outer link, said rst inner link and said first spring being located in the portion of the outer link adjacent said one end thereof and said second inner link and said second spring being located in the portion of the outer link adjacent said other end thereof, an end of each of said springs being anchored to said outer link, the other end of said first spring acting on and being movable with said first inner link to Wind said first spring in response to the longitudinal movement of said inner link out of said one end of said outer link, the other end of said second spring acting on and being movable with said second inner link to wind said second spring in response to longitudinal movement of said second inner link out of said other end of said outer link, each of said inner links overlying the coil of its spring adjacent said other end thereof and extending in a direction generally perpendicular to the central axis of its coil spring, said telescopical and longitudinal movements of said inner links being in opposite directions and generally perpendicular to the central axes of said coil springs, said other end of each of said springs extending outwardly from the coil of its spring in a direction generally parallel to the central axis of the coil and engaging its inner link, said springs being located in a spring receiving compartment in said outer link, said compartment having an upper Wall, a lower wall, and a pair of side walls, said upper wall facing one end of each of the coils and the lower wall facing the other end, the wall of said compartment facing the ends of the coils from which said other ends of said springs extend having a pair of elongated slots extending in a direction from end to end of the band, one on each side of the longitudinal center line of the band, one slot extending from the mid portion of said last mentioned wall with respect to the ends thereof towards said one end of the outer link and receiving said other end of said first spring and the other slot extending from a mid portion of said wall with respect to the ends thereof toward said other end of said outer link and receiving said other end of said second spring, said other end of said first spring moving along its slot toward said one end of the outer link during winding thereof by movement of said rst inner link out of said one end, and said other end of said second spring moving along its slot toward said other end of Said outer link during winding thereof by movement of said second link out of said other end of said outer link.

12. A band according to claim l1, each of said inner links being located in said compartment between said slotted wall and the end of the coil of its spring facing said slotted wall, said springs being cylindrical coil springs and partially compressed when the band is retracted, the wall of said compartment opposite said slotted wall and adjacent the other ends of said coils being recessed intermediate the sides thereof, said recess being spaced from said sides to form a pair of raised side margins, said springs being located in said recess, each of said inner links comprising a pair of opposite crossbars extending in a direction from side to side of the band and a pair of opposite side bars extending in a direction generally parallel to the longitudinal center line of the band, said bars of each of said inner links forming a central opening axially aligned with the coil of its spring, said side bars being located between said slotted wall and said raised side margins of said opposite wall, said other end of said first spring engaging the inner edge of the inner crossbar of said irst inner link to urge the link into said one end of said outer link and toward the second inner 11 link, said other end of said second spring engaging the inner edge of the inner crossbar of the second inner link to urge said second inner link toward the iirst inner link, said springs urging said inner crossbars into engagement with each other when the band is retracted with said inner crossbars being located in the midportion of the outer link with respect to the ends thereof and the other outer crossbars of said inner links being located adjacent the ends of the outer link.

13. A band according to claim 12, each inner crossbar of each inner link having a tab extending -frorn the center portion of the inner edge thereof, said outer link having a pair of opposite end Walls to prevent said inner links from being moved completely out of the opposite ends of said outer link, the opposite side portions of each of said end walls having openings for receiving the side bars of an inner link, said last mentioned openings registering with the marginal spaces between said raised side margins and said slotted wall, the midportion of each of said end walls having an opening to receive the tab of an inner link when the bracelet is extended to its maximum length.

14. A band according to claim 13, including means for anchoring said one end of said iirst spring to a portion of the floor of said recess directly adjacent to and within one end wall between the middle opening thereof and a side opening thereof on one side of the longitudinal center line of said band and for anchoring said one end of said second spring to a portion of said floor directly adjacent to and Within the other end Wall between the middle opening thereof and a side opening thereof on the other side of said center line, said other ends of said springs being located at the midportion of the outer link with respect to the ends thereof when the band is retracted one on either side of the longitudinal center iine of the band.

15. A band according to claim 14, the inner sides of said slots extending from a midportion of said slotted wall with respect to the ends thereof at points at opposite sides of said longitudinal center line, in opposite directions toward the opposite ends and opposite sides of said wall, said side bars extending inwardly beyond the outer sides of said slots, said other end of each of said springs engaging the corner formed by the inner edge of the inner crossbar of its inner link and the side bar of said inner link and being bent over its inner link.

References Cited in the tile of this patent UNTTED STATES PATENTS