Expandable light string

Apparatus and associated methods relate to a light string having pluralities of lighting elements and expandable links thereon, so as to facilitate expansion of the light string in response to applied tensile forces. Each of the expandable links includes a segment of flexible cable between an adjacent pair of the lighting elements and an expansion member mechanically engaging the segment of the flexible cable at first and second engagement portions. Each of the expandable links is in a natural state if no tensile force is applied between the first and second engagement portions and in an expanded state if a tensile force is applied between the first and second engagement portions. In the natural state, an arcuate portion of the flexible cable is between the first and the second engagement portions. The arcuate portion of the flexible cable changes shape in response to an applied tensile force applied therebetween.

BACKGROUND

Decorative light strings are used to communicate a joy of a holiday season, to draw attention to merchandise, or to simply decorate or adorn an object. Decorative light strings can be used both indoors and outdoors. Decorative light strings have been used residentially to adorn trees, shrubs, and houses. Commercial businesses can use decorative light strings to provide festive atmospheres at their places of business.

Often light strings are placed on trees and shrubs shortly before a festival and/or holiday season, and then removed after the festival and/or holiday season has ended. Trees and shrubs grow very little during the time span of the festival and/or holiday season. If, however, the light strings were left adorning the trees and shrubs for longer periods of time, the natural growth of trees and shrubs can cause tensile forces along the length of the light strings, and/or constrict the trees and shrubs. Such tensile forces can result in death of the trees and shrubs and or destruction of the light strings if the forces are not reduced in a sufficient time.

This disclosure is directed to providing elastic expansion capabilities to decorative light strings, so as to permit the decoration of such things that can have the possibility of applying tensile forces to the decorative light string.

SUMMARY

Apparatus and associated methods relate to an expandable light string. The expandable light string includes a flexible cable having a plurality of conductive wires extending and providing electrical conduction between a first electrical connector at a first end and a complementary second electrical connector at a second end. The first electrical connector is configured to receive operating power and the complementary second electrical connector is configured to provide operating power. The expandable light string also includes a plurality of lighting elements distributed along the flexible cable. Each of the plurality of lighting elements is configured to illuminate in response to receiving operating power from the plurality of conductive wires. The expandable light string also includes a plurality of elastic expansion members. Each of the elastic expansion members mechanically engages the flexible cable at first and second engagement portions between an adjacent pair of lighting elements. An arcuate portion the flexible cable is between the first and the second engagement portions if no expansion force is applied therebetween.

Some embodiments relate to an expandable light string that includes a flexible cable having a plurality of conductive wires extending and providing electrical conduction between a first electrical connector at a first end and a complementary second electrical connector at a second end. The first electrical connector is configured to receive operating power and the complementary second electrical connector configured to provide operating power. The expandable light string also includes a plurality of lighting elements distributed on the flexible cable. Each of the plurality of lighting elements is configured to illuminate in response to receiving operating power from the plurality of conductive wires. The expandable light string also includes a plurality of expandable links. Each of the expandable links includes a segment of the flexible cable between an adjacent pair of the lighting elements and an expansion member mechanically engaging the segment of the flexible cable at first and second engagement portions. Each of the expandable links is in a natural state if no tensile force is applied between the first and second engagement portions and in an expanded state if a tensile force is applied between the first and second engagement portions, wherein, in the natural state, an arcuate portion of the flexible cable is between the first and the second engagement portions.

DETAILED DESCRIPTION

Apparatus and associated methods relate to a light string having pluralities of lighting elements and expandable links thereon, so as to facilitate expansion of the light string in response to applied tensile forces. Each of the expandable links includes a segment of flexible cable between an adjacent pair of the lighting elements and an expansion member mechanically engaging the segment of the flexible cable at first and second engagement portions. Each of the expandable links is in a natural state if no tensile force is applied between the first and second engagement portions and in an expanded state if a tensile force is applied between the first and second engagement portions. In the natural state, an arcuate portion of the flexible cable is between the first and the second engagement portions. The arcuate portion of the flexible cable changes shape in response to an applied tensile force applied therebetween.

FIG. 1is a schematic view of a tree decorated with an expandable light string. InFIG. 1, tree10has been decorated with series connected expandable light strings12A,12B and12C. Each of expandable light strings12A,12B and12C includes a flexible cable14A,14B,14C, a plurality of lighting elements16A,16B,16C and a plurality of expandable links18A,18B,18C, respectively. Flexible cables14A,14B and14C extend between first electrical connectors20A,20B and20C at first ends and complementary second electrical connectors22A,22B and22C at second ends of expandable light strings12A,12B and12C, respectively.

Each of flexible cables14A-14C includes two or more conductive wires so as to provide electrical conduction between first electrical connectors20A-20C and complementary second electrical connectors22A-22C, respectively. First electrical connectors20A-20C are configured to receive operating power from sources connected thereto. Second electrical connectors22A-22C are configured to provide operating power to other expandable light strings and/or electrical devices connected thereto. First and second electrical connectors20A-20C and22A-22C are complementary one to another, so as to facilitate the depicted series connection of expandable light strings.

The plurality of lighting elements16A-16C is distributed on flexible cables12A-12C. Each of the plurality of lighting elements16A-16C is configured to illuminate in response to receiving operating power from the plurality of conductive wires in flexible cables12A-12C. In some embodiments, lighting elements16A-16C include incandescent bulbs. In some embodiments, lighting elements16A-16C include Light Emitting Diodes (LEDs).

Each of the plurality of expandable links18A-18C is configured to facilitate expansion of expandable light strings12A-12C. Flexible cables14A-14C can have a high tensile strength so as to provide good resistance to expansion. For example, a 14 gauge copper wire can have a tensile strength of 70 pounds. If more than 70 pounds of force is applied, the 14 gauge copper wire can break. Flexible cables14A-14C can have two, three, or more conductive wires extending between connectors22A-22C. The tensile strength of flexible cables14A-14C increases as the number of conductive wires extending between connectors22A-22C increases. But the tensile strength of flexible cables14A-14C decreases as the diameter of the conductive wires extending between connectors22A-22C decreases. If, for example, each of flexible cables14A-14C has three 20 gauge conductive wires of 28 pound tensile strengths extending between connectors22A-22C, the total tensile strength will be around 84 pounds. In some embodiments, the tensile strength of flexible cables14A-14C is at least 25 Newtons, 50, 75, 100 or 200 Newtons or more. Such high-tensile-strength flexible cables typically do not expand very much in response to tensile forces that are less than the tensile strength of the flexible cable.

FIG. 2Ais a schematic diagram of a flexible cable having an arcuate portion which can expand in response to a tensile force. InFIG. 2A, exemplary flexible cable14includes arcuate portion24. Arcuate portion24connects first straight section26and second straight section28. Arcuate portion24can deform and/or straighten in response to forces FLand FR, as depicted in the figure, applied to ends30and32of straight sections26and28, respectively. Conductive wires, especially stranded conductive wires, typically do not offer high resistance to such deformation, and typically provide little return-to-arcuate-form memory. Without an expansion member to prevent arcuate portion24from deforming, the deformation of arcuate portion24may occur as expandable light strings12A-12C are being strung about trees and/or shrubs. If such deformation of arcuate portion24occurs during such decoration activity, expandable light strings12A-12C will not readily expand further in response to future tensile forces.

FIGS. 2B-2Care schematic diagrams of an embodiment of an expandable link using the arcuate portion shown inFIG. 2A. InFIG. 2B, expandable link18is depicted in its natural state with no tensile forces applied thereto. Expandable link18includes a segment of flexible cable14and expansion member34mechanically engaging the segment of the flexible cable14at first and second engagement portions36and38. Expansion member34is a longitudinal elastomer having first and second lumens. First engagement portion36of the flexible cable18is engaged within the first lumen. Second engagement portion38of flexible cable18is engaged within the second lumen. Expandable link18is in a natural state if no tensile force is applied between the first and second engagement portions36and38as is depicted inFIG. 2B. In its nature state, arcuate portion24is in the arcuate form depicted inFIG. 2A.

InFIG. 2C, expandable link18is depicted in its expanded state with a tensile force applied thereto. Expandable link18includes a segment of flexible cable14and expansion member34mechanically engaging the segment of the flexible cable18at first and second engagement portions36and38. Expandable link18is in an expanded state if tensile forces FRand FLare applied between the first and second engagement portions36and38as is depicted inFIG. 2C. Expandable link18will be in the expanded state if a tensile force is applied between the first and second engagement portions36and38. In the expanded state, arcuate portion24is deformed in an elongate fashion as is depicted inFIG. 2C. Expansion member34is configured to permit a separation distance between the adjacent pair of lighting elements, between which expandable link18resides, to increase in response to an expansion force therebetween.

In the embodiment depicted inFIGS. 2B and 2C, expansion member34is configured to contract in response to a reduction of the tensile force between the first and second engagement portions36and38. Thus, expansion member34is configured to permit a separation distance between the adjacent pair of lighting elements, between which expansion link18resides, to decrease in response to a reduction of the expansion force.

FIGS. 3A-3Bare schematic diagrams of an embodiment of an expandable link using a flexible cable having an S-shaped arcuate portion. InFIG. 3A, expandable link18′ is depicted in its natural state with no tensile forces applied thereto. Expansion link18′ includes a segment of flexible cable14and expansion member34′ mechanically engaging the segment of flexible cable14at first and second engagement portions36′ and38′. Arcuate portion24′ of flexible cable14is between first and second engagement portions36′ and38′. In response to a tensile force FLand FR, as depicted in the figure, arcuate portion24′ will release a length of flexible cable14from within expansion member34′, thereby decreasing a lateral dimension of S-shaped arcuate portion24′.

InFIG. 3B, expansion link18′ is depicted in its expanded state with a tensile force applied thereto. Expansion link18′ includes a segment of flexible cable14and expansion member34′ mechanically engaging the segment of flexible cable14at first and second engagement portions36′ and38′. Arcuate portion24′ of flexible cable14is between first and second engagement portions36′ and38′. In response to a tensile force FLand FR, as depicted in the figure, arcuate portion24′ has released a length of flexible cable14from within expansion member34′, thereby decreasing a lateral dimension of S-shaped arcuate portion24. In the embodiment depicted inFIGS. 3A-3B, expansion link18′ is configured to expand in response to a tensile force between first and second engagement portions36′ and38′. Expansion link18′ is not configured to contract, however, in response to a reduction of the tensile force therebetween.

Various embodiments may use various materials for expansion member34′. For example, some embodiments may use heatshrink for expansion member34′. Some embodiments may use an adhesive tape for expansion member34′. In some embodiments, flexible expansion member34′ may be formed from a cylinder of a plastic material. In some embodiments, expansion member34′ can be substantially flexible, and in other embodiments expansion member34′ can be substantially inflexible.

FIG. 4Ais a schematic diagram of an embodiment of an expandable link. InFIG. 4A, expandable link18″ is depicted in its natural state with no tensile forces applied thereto. Expandable link18″ includes a segment of flexible cable14and expansion member34″ mechanically engaging the segment of the flexible cable14at first and second engagement portions36″ and38″. Arcuate portion24″ of flexible cable14is between first and second engagement portions36″ and38″.FIG. 4Bis a schematic diagram of an embodiment of expansion member34″ depicted inFIG. 4A. InFIG. 4B, expansion member34″ includes cable engagement apertures40and42.

Various other embodiments can provide elastic expansion capabilities to a light string. In some embodiments, an expansion member (e.g., expansion member34′) slideably engages a flexible cable (e.g., flexible cable14). In some embodiments, an expansion member (e.g., expansion members34and34″) fixedly couples to flexible cable18. Various elastomers can be attached to first and second engagement portions of the flexible cable so as to have an arcuate portion (e.g., arcuate portions34,34′ and34″) of the flexible cable between the first and second engagement portions (e.g., first and second expansion portions36,36′,36″,38,38′ and38″), if the elastomer is in its natural state. Such elastomers and/or expansion members have a spring constant that is less than a spring constant of the flexible cable to which it is attached. For example, various expansion members have a spring constant of less than 200 N/m or 100, 50, 25 or less than 10 N/m or less.

In some embodiments, a ratio of a fully expanded light string to an unexpanded light string can be greater than 1.05, 1.10, 1.15, or greater than 1.25 or more. An unexpanded light string is one in which the light string has not been expanded by a tensile force. A light string is fully expanded if a tensile force greater than a predetermined threshold is applied to the entire plurality of expandable links. The predetermined force can be greater than 5 N, or 7 N, 10 N, 15 N, or more.