fig1 shows a necklace 10 comprising a combination of links that resists flipping and twisting . a clasp 12 completes the necklace 10 . one type of link 20 , illustrated in fig2 and 3 , enables articulation vertically or up - and - down , i . e ., in the vertical plane of the link 20 , with respect to its length ( designated by the arrow “ l ”). the dashed line labeled “ vertical ” lies in the vertical plane with respect to the length of the link . each such vertically - articulating link 20 has a first hinge element 22 and a second hinge element 24 that mates with the appropriate hinge elements 24 and 22 , respectively , of other similar links 20 to enable such vertical or up - and - down articulation , as illustrated in fig4 ( links separated ), fig5 ( links joined ), and fig6 ( links with articulation ). by virtue of the action of the hinge elements 22 and 24 , the vertically - articulating link 20 restricts articulation to the vertical plane . another type of link 30 , illustrated in fig7 and 8 , enables articulation horizontally or side - to - side , i . e ., in the horizontal plane of the link 30 , with respect to its length ( designated by the arrow “ l ”). the dashed line labeled “ horizontal ” lies in the horizontal plane with respect to the length of the link . each such horizontally - articulating link 30 has a first hinge element 32 and a second hinge element 34 that mates with the appropriate hinge elements 34 and 32 , respectively , of other similar links 30 to enable such horizontal or side - to - side articulation , as illustrated in fig9 ( links separated ), fig1 ( links joined ), and fig1 ( links with articulation ). by virtue of the action of the hinge elements 32 and 34 , the horizontally - articulating link 30 restricts articulation to the horizontal plane . additionally , the necklace 10 may also contain interconnecting links 40 and 50 , shown in fig1 and 13 , respectively . the first such interconnecting link 40 ( fig1 ) has a first hinge element 42 that enables horizontal or side - to - side articulation and a second hinge element 44 that enables vertical or up - and - down articulation . the second such interconnecting link 50 ( fig1 ) has a first hinge element 52 that enables vertical or up - and - down articulation and a second hinge element 54 that enables horizontal or side - to - side articulation . the first interconnecting link 40 is shown in a segment of three links — a vertically or up - and - down articulating link 20 followed by the first interconnecting link 40 and then a horizontally or side - to - side articulating link 30 , separately in fig1 , coupled together in fig1 , and then articulated in fig1 . ( the dashed lines labeled “ vertical ” and “ horizontal ” lie in the vertical and horizontal planes , respectively , with respect to the length of the link .) the second interconnecting link 50 is similarly shown in a segment of three links — a horizontally or side - to - side articulating link 30 followed by the second interconnecting link 50 and then a vertically or up - and - down articulating link 20 , separately in fig1 , coupled together in fig1 , and then articulated in fig1 . in its most basic form , the necklace 10 will comprise a number of vertically ( or up - and - down ) articulating links 20 and a number of horizontally ( or side - to - side ) articulating links 30 . where the necklace 10 lays against the neck , the vertically or up - and - down articulating links 20 permit the necklace 10 to follow the contour of the neck . below the neck , the necklace 10 should lay flat against the wearer &# 39 ; s chest , which is achieved by utilizing horizontally or side - to - side articulating links 30 . because any given coupling of links 20 or 30 will allow articulation in only one manner , either in an up - and - down or a side - to - side fashion , the necklace 10 will resist flipping or twisting . the actual number of each type ( links 20 and links 30 ) depends in part on the length of the necklace 10 and the circumference of the wearer &# 39 ; s neck . an equal number of each ( links 20 and links 30 ) will work satisfactorily but a different ratio of links 20 and 30 could be employed as suits the application , for example , in a lengthy necklace where a substantial portion of the necklace 10 lays against the chest as opposed to against the neck of the wearer . the necklace 10 is shown again in fig2 . the first and second interconnecting links 40 and 50 join the vertically or up - and - down articulating links 20 on the upper portion 14 of the necklace 10 ( the top portion of the page ) to the horizontally or side - to - side articulating links 30 on the lower portion 16 of the necklace 10 . again , the necklace 10 is completed by a clasp 12 which substitutes for one of the vertically or up - and - down articulating links 20 . recalling the directional references of fig2 and 12 , the necklace lies of fig2 lies in the horizontal plane while the vertical plane is perpendicular to the page . in the figures , the links are shown in various sizes , alternating between large and small . one may use different size links to accommodate different sizes of gemstones or , should the gemstones all be equal in size , then the links may also be of equal dimensions . in lieu of using the first and second interconnecting links 40 and 50 to interconnect the vertically articulating links 20 to the horizontally articulating links 30 , a coupling device consisting of a hinge element that enables horizontal or side - to - side articulation and a second hinge element that enables vertical or up - and - down articulation would be sufficient to interconnect the links of differing articulation , without the need to accommodate a gemstone . further , the other links of the necklace 10 could also assume a different form and not carry gemstones , i . e ., all metal .
twisting and flipping of a necklace along its length may be prevented by restricting the articulation of the links . by providing one section with links that permit articulation only in a vertical direction and another section with links that permit articulation only in a horizontal direction , flipping and twisting can be prevented .