Modular retractile telephone cords

Information

  • Patent Grant
  • 6235990
  • Patent Number
    6,235,990
  • Date Filed
    Tuesday, January 5, 1999
    25 years ago
  • Date Issued
    Tuesday, May 22, 2001
    23 years ago
Abstract
A convenient compact telephone cord with a special coil diameter and a much smaller relaxed retracted length reduces sagging, occupies less space, and is much more attractive than conventional saggy telephone cords. The user-friendly high performance telephone cord has a core of electrical conductors which are insulated by primary insulation and are encased within an insulating jacket to meet or exceed national and international telephone standards and requirements. In the preferred form, the primary insulation comprises polypropylene and the insulating jacket comprises polyurethane and most preferably a blend of polyurethane and ethylene vinyl acetate. Desirably, the telephone cord comprises a modular retractile telephone cord with at least one modular plug. The attractive space-saving telephone cord can be used with handsets, headsets, vehicle phones, modems, and computers.
Description




BACKGROUND OF THE INVENTION




This invention pertains to telephone cords and, more particularly, to modular telephone cords.




Telephone cords are usually wound and coiled on mandrels to form spirals. Desirably, spiral telephone cords can be extended when using the telephones to which they are connected, and can be returned to their original retracted position when the telephones are not in use. Telephone cords have many uses.




Telephone cords used to connect a handset to a base should have sufficient retractility to insure that they will return in a controlled gradual manner to their normal retracted position after having been extended and released. Coiled or spiral telephone cords, however, which also known as “spring cords” or “retractile cords” should not be so strongly retractile that they require excessive forces to extend the telephone cord. If the telephone cord is too unyielding, the telephone handset or device to which the telephone cord is connected may be removed on or pulled from its support. While excessive retractility should be avoided, a telephone cord should not be made so stretchable that its distended spirals fail to return to their retracted position after using the telephone. This is especially important in order to prevent unsightly, excessive sag of telephone cords which are used on wall-mounted telephones. Furthermore, it is desirable that the retracted length of the telephone cord be as short as possible so as to be unobtrusive and avoid taking up excessive space and being distractive. In order to avoid this situation, telephone cords that are connected to telephone handsets must extend easily, perform dependably, and be as short as possible in their retracted position.




Retractable telephone cords are often constructed of cordage of individually insulated, mandrelated flexible conductor comprising tinsel ribbons. Conventional telephone cords are also often covered with nylon, insulated with polyvinyl chloride (PVC), and jacketed with a PVC composition in a circular configuration.




Telephone cords which utilize modular plugs for terminating the cord conductors are known as “modular telephone cords” . Jacks adapted to receive the modular plugs are mounted in the telephone housing or base and in a wall terminal thereby permitting easy replacement of either the line or retractile cord by a customer or an installer. Modular telephone cords have become very popular with consumers and telephone serviceman because of their ease of use and interchangeability.




The popularity of modular telephone cords with its associated plug-terminated cordage inspired the development of telephone cordage having a smaller cross-section than that used in the past. Conventional telephone cordage design suitable for use with modular plugs typically have smaller conductors arranged in a parallel relationship, positioned in a single plane, and encapsulated with a flattened oval-shaped jacket. To reduce the size of the insulated conductor, the knitted nylon covering the tinsel conductors was often eliminated and replaced with a crystalline thermoplastic elastomer.




It has been found that if top coated cordage is formed into a spring cord configuration, it has excellent retractile properties. However, when top-coated cordage is formed on mandrels of automatic cord making apparatus, the finished cords are so strongly retractile that excessive forces are required to stretch and expand the telephone cord. This problem occurs not only because of the top coating but also because of the relatively small diameter of the convolutions of the cordage. The diameter which is about 0.64 cm has been increased by forming the convolutions on larger diameter mandrels to achieve a top-coated cord having a larger diameter such as for example on the order of 0.95 cm. Although such prior art cords are suitably extensible, they lack good retractility. This is particularly noticeable in prior telephone cords which are used on wall-mounted telephones and which are desired to have an extended length of 7.6 meters and a retracted length of about 1 meter.




It is, therefore, desirable to provide improved modular retractile telephone cords which overcome most, if not all, of the preceding problems.




SUMMARY OF THE INVENTION




An improved telephone cord is provided which is compact, reliable, and economical. Advantageously, the space-saving telephone cord reduces sagging, is less obtrusive, and occupies a smaller area than conventional bulky saggy telephone cords. The attractive space-saving telephone cord is easy-to-use, convenient and effective. Desirably, the user-friendly telephone cord complies with telephone standards and requirements in the United States, Europe, Japan, and other countries. The novel telephone cord also achieved unexpected surprisingly good results.




The inventive telephone cord can be used as: a telephone handset cord for use with telephone handsets, a telephone headset cord for use with telephone headsets, a telephone vehicle cord for use with car phones or vehicles phones, a data transmission or receiving cord such as a telephone computer cord for use with a microprocessor, computer or central processing unit (CPU), or a telephone modem cord for use with a modem.




The telephone cord preferably comprises a modular retractile (retractable) telephone cord with at least one modular telephone plug at one end. The other end of the telephone cord can be connected to another modular telephone plug, or a different plug, or hardwire or otherwise connected to a telephone line or other circuitry. The modular telephone plug snap fits into a socket, jack, receptacle or other complementary-shaped female connector, in a telephone handset, base unit, wall receptacle, headset, etc.




The retractile telephone cord has a core comprising 2 to 8 conductors, preferably 4 to 7 conductors. For data transmission or receiving telephone cords, it is preferred that the conductors are twisted. For voice transmission or receiving telephone cords, it is preferred that the conductors are substantially parallel. The conductor can comprise wires, strands, or a flexible tinsel ribbon.




The conductors can be electrically insulated, isolated and separated from each other by primary insulation. The primary insulation can comprise an insulating material such as: a crystalline thermoplastic elastomer, polyethylene, polyvinyl chloride (PVC), nylon (polyamide), neoprene (polychloroprene)(polymerized chloroprene), polyurethane, polyurethane diisocyanate, urethane, butadiene, polystyrene, natural rubber (natural polyisoprene), styrene butadiene, acrobonitrile-butadiene, butyl rubber, vulcanized Hevea, Buna S, polysulfone, silicone, polysiloxane, chlorosulfanated polyethylene, or preferably polypropylene.




The retractile telephone cord can have a unitary or composite outer protective jacket positioned about the primary insulation and core. The outer protective jacket provides secondary insulation and can comprise an elastomeric insulating material, such as: polytetrafluroethylene (PTFE)(Teflon), polyvinyl chloride, nylon, neoprene, butadiene, polystyrene, styrene butadiene, acrolonitrile-butadiene, butyl rubber, vulcanized Hevea, Buna S, polysylfone, silicone, natural rubber, polyethylene, polypropylene, chlorosulfanated polyethylene, polysiloxane, or preferably polyurethane, polyurethane diisocyanate, or urethane, and most preferably, a blend of polyurethane and ethylene vinyl acetate (EVA). If desired, at least part of the jacket can be coated with another elastomeric insulating material.




The retractile telephone cord has a coiled portion between the ends of the cord. The coiled portion can be wound or coiled into spirals or helixes. The coiled portion has coils which have a maximum outside coil diameter when the telephone cord is in a relaxed retracted position. The coiled portion can be uniform and even in which all the coils have the same uniform maximum outside coil diameter. The coiled portion can also be tapered in which at least some of the coils have a different maximum outside coil diameter. Advantageously, the maximum outside coil diameter of the compact telephone cord is greater than 0.5 inches (12.07 mm), preferably at least 0.75 inches (19.05 mm), and most preferably at least one inch (245 mm). As used in this application, the terms “maximum coil diameter” and “maximum outside coil diameter” mean the maximum transverse span or the maximum outside diameter of the particular coil, spiral, helix, or loop of the telephone cord when the telephone cord is relaxed, unpulled, unstretched or retracted.




The compact retractile telephone cord can have a nominal uncoiled total length of 6 feet (1.8288 m), 12 feet (3.6576 m), or 25 feet (7.26 m), but has a much smaller relaxed retracted length than conventional telephone cords. The telephone cord can be expanded to an extended length of 790 to 7240 mm, preferably at least 1880 mm. The compact telephone cord can have a normal relaxed retracted length or recovered length of 70 to 1470 mm, preferably 150 to 648 mm. In the illustrative embodiment, the telephone cord had a recovered length ranging from 70 to 1140 mm after being subjected to a load of 170 gm for 300 seconds.




A more detailed explanation of the invention is provided in the following description and appended claims taken in conjunction with the accompanying drawings.











BRIEF DESCRIPTION OF THE DRAWINGS





FIG. 1

is a front view of a modular telephone cord for voice transmission and receiving with a uniform diameter coiled portion in accordance with principles of the present invention;





FIG. 2

is an enlarged cross-sectional view of the modular telephone cord of

FIG. 1

;





FIG. 3

is a front view of a modular telephone cord for voice transmission and receiving with a tapered coiled portion in accordance with principles of the present invention;





FIG. 4

is an enlarged cross-sectional view of a modular telephone cord for data transmission and receiving;





FIG. 5

is a fragmentary front view of the modular telephone cord of

FIG. 4

without the modular plugs and illustrating the twisted conductors of the interior core;





FIG. 6

is a perspective view of a modular telephone cord connected to a telephone for positioning on a table; and





FIG. 7

is a perspective view of a modular telephone cord connected to a wall-mounted telephone.











DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS




Compact space-saving large diameter modular retractile (retractable) telephone cords


10


,


32


and


50


(

FIGS. 1

,


3


, and


5


) are provided with much smaller relaxed retracted lengths to reduce unsightly sagging and occupy much less space than previous conventional telephone cords.




The telephone cord


10


(

FIGS. 1 and 6

) can comprise a telephone handset cord for connecting a telephone handset to a telephone base unit. The telephone handset cord comprises a modular retractile telephone cord which provides a cordage assembly


12


with a spiral wound coiled portion


14


that extends between and is connected to a handset-facing end


16


and a base-facing end


18


of the telephone cord. The spiral wound coiled portion comprises a series, set, or array of coils


20


which provide loops. The coil preferably comprise spiral coils (spirals), and most preferably helical coils (helixes).




The modular telephone cord has at least one modular plug


22


(

FIG. 1

) connected to one of the ends of the telephone cord, and preferably has two plastic modular telephone plugs


22


and


24


connected to opposite ends of the telephone cord. The telephone handset cord has a handset-connecting modular plug


22


which is connected to the handset-facing end of the telephone cord and has a base-connecting modular plug


24


which is connected to the base-facing end of the telephone cord. The handset-connecting modular plug provides a telephone handset connector which snap fits and interlockingly engages, as well as can be detachably secured and removably connected to a complementary-shaped female socket or jack of a telephone handset. The base-connecting modular plug provides a base unit connector which snap fits and interlockingly engages, as well as can be detachably secured and removably connected to a complementary-shaped female socket or jack of a telephone base unit.




Each of the modular plugs has a wedging cantilevered connecting arm


26


or


27


(

FIG. 1

) which is connected to and normally biased outwardly at an angle of inclination away from the front nose


28


or


29


of the head


30


or


31


or body of the modular plug. The connecting arm extends generally towards the coiled portion of the telephone cord, but normally diverges away from the end of the cord to which the modular plug is connected. The connecting arm can be squeezed and pivoted toward and against the side of the head or body of the modular plug, when the modular plug is inserted or removed from a socket or jack of a handset, base unit, headset, wall receptacle, computer, modem, appliance, or other apparatus. When inserted into a complementary socket or jack, the connecting arm of the modular plug securely wedges against, snap fits, and lockably engages the adjoining wall portious of the socket or jack.




The modular retractile telephone cord is biased in a normally relaxed retracted position to a collapsed retracted length when the telephone cord is stored, awaiting use, unstretched, unpulled, relaxed, and retracted. The modular retractile telephone cord can be expanded to an elongated stretched extended position to an extended length when the telephone cord is pulled, stretched, and extended. The telephone handset cord is biased and urged in a normally relaxed position when the handset is cradled or seated on the base unit when the telephone is not in use and no voice signals or data pulses are being sent (transmitted) or received. The telephone handset cord is expanded to an elongated stretched extended position when the handset is moved away from the base unit when the telephone is in use and voice signals or data pulses are being transmitted or received. Preferably, the extended length is at least 5 times greater than the retracted length of the telephone cord. Desirably, the retracted length of the telephone cord is less than 15%, preferably less than 10%, of the extended length of the telephone cord. The telephone cords are preferably produced in nominal total uncoiled lengths of 6 feet (ft.) (1.8288 m), 12 ft. (3.6576 m) and 25 ft. (7.62 m).




The coils of the modular telephone cord have a greater maximum coil diameter and are positioned closer together when the telephone cord is in a relaxed retracted position. The coils have a maximum coil diameter of 0.5 inches (12.07 mm), preferably at least 0.75 inches (19.09 mm), and most preferably at least one inch, (25.55 mm), when the telephone cord is in a retracted position. In the telephone cord of

FIG. 1

, the coiled portion is uniform and comprise uniform coils, preferably spiral coils, and most preferably helical coils, having the same maximum coil diameter when the telephone cord is in the retracted position. Conversely, the coils have a smaller coil diameter and are positioned farther apart when the telephone cord is stretched or expanded to its maximum extended position.




The modular telephone cord


32


of

FIGS. 3 and 7

is structurally and functionally similar to the modular telephone cord of

FIG. 1

, except that the coiled portion comprises a sloping bulging barrel-shaped tapered coiled portion


34


in which the coils


36


gradually taper, increase or decrease in size. At least some of the coils of the tapered coil portion have different maximum coil diameters when the telephone cord is in a retracted position.




The cordage assembly of the modular telephone cord can comprise a core


40


(

FIG. 2

) with 2 to 8 and preferably 4 to 7 electrical conductors


42


. For voice transmission and receiving, the conductors preferably comprise parallel flexible electrical conductors, most preferably flexible tinsel ribbon


44


comprising flexible tinsel wire strands. The tinsel ribbon can be made of phosphorous bronze or other suitable conductive material.




The modular telephone cord


50


of

FIGS. 4 and 5

are structurally and functionally similar to the modular telephone cord of

FIG. 1

, except that the conductors of the core


51


are twisted to form twisted conductors


52


which provide a cable to transmit and receive data. In one preferred form, each of the conductors comprise 26-28 AWG (American Wire Gauge) wire and have a diameter ranging from 0.015 inches (0.38 mm) to 0.024 inches (0.61 mm). Preferably, the conductors have a tensile pull strength of at least 44.5 N.




The electrical conductors are electrically insulated, isolated, and physically separated from each other by primary insulation


54


(FIGS.


2


and


4


). In the preferred form, the primary insulation comprises polypropylene, has an insulation resistance more than 150 Ω·km, and has a dielectric constant at 10


6


Hz of 2.20-2.28. The dielectric strength between conductors is such that there is no breakdown at 1000 VAC for one minute. Preferably, the primary insulation has a wall thickness greater than 0.004 inches (0.1016 mm).




The cordage assembly of the modular telephone cord has an outer protective jacket


56


or


58


(

FIGS. 2 and 4

) which provides a secondary insulation and an electrical insulation sheath that annularly surrounds, encloses and encases the primary insulation and core of conductors. In the preferred form, the outer protective jacket comprises urethane or most preferably polyurethane, with a dielectric constant at 10


6


Hz of 5-8. Desirably, the outer protective jacket comprises a blend of polyurethane and ethylene vinyl acetate (EVA), such as by weight: 80% polyurethane and 20% EVA, and preferably, 90% polyurethane and 10% EVA. The composite outer protective jacket can comprise by weight: 50%-99% polyurethane and 1%-50% EVA. Preferably, the outer protective jacket has a wall thickness greater than 0.1 inches (2.54 mm) and a tensile strength greater than 1200 psi (84,368,35 g/cm


2


). If desired, part or all of the exterior surface of the outer protective jacket can be coated with an elastomeric insulating layer


60


(coating) (FIG.


2


), such as a 0.005 cm layer of polyester or other plastic, to enhance protection, insulation, and retractility. The outer protective jacket


56


(FIG.


2


), enclosing the parallel conductors preferably has a generally elliptical or oval exterior surface


62


, periphery and shape. The outer protective jacket


56


positioned about the parallel conductors can also have parallel elongated sides


64


and


66


and curved arcuate ends


68


and


70


. The outer protective jacket


58


(

FIG. 4

) enclosing and positioned about the twisted conductors can have a circular exterior surface


72


, periphery and shape.




The illustrated modular telephone cords can also be used as: telephone headset cords for use with telephone headsets, telephone vehicle cords for use with car phones or vehicle phones, data transmission or receiving cords such as telephone computer cords for use with microprocessors, central processing units (CPUs), and computers, or telephone modem cords for use with modems.




EXAMPLES 1-8




Retractile telephone cords of the type described above were formed with a maximum outside coil diameter of 0.75 inches (19.05 mm). The telephone cords had a uniform outside coil diameter as shown in FIG.


1


. The telephone cords were also constructed with an oval cross-sectional configuration with elongated flattened sides as shown in FIG.


2


and had an interior core comprising four flexible tinsel copper conductors. The conductors were insulated with a polypropylene primary insulation.




Telephone cords


1


-


3


had an outer protective jacket consisting essentially of polyurethane. Telephone cords


4


-


6


had an outer protective jacket consisting essentially of polyvinyl chloride (PVC). Telephone cords


7


and


8


had composite outer protective jacket consisting essentially of by weight: 90% polyurethane and 10% ethylene vinyl acetate (EVA). Telephone cords


1


and


4


had a total nominal uncoiled length of 6 feet (1.8288 mm). Telephone cords


2


,


5


and


7


had a total nominal uncoiled length of 12 feet (3.6576 m). Telephone cords


3


,


6


and


8


had a total nominal uncoiled length of 25 feet (7.26 m).




The telephone cords had a retracted length as shown in Table 1 as follows:












TABLE 1











Retracted Length



















Re-






Exam-




Retractile




Total Nominal





tracted






ple




Telephone




Uncoiled Length





Length






No.




Cord




(feet)




Outer Protective Jacket




(mm)









1




1




 6 (1.8288 m)




Polyurethane




150






2




2




12 (3.6576 m)




Polyurethane




287






3




3




25 (7.26 m)




Polyurethane




848






4




4




 6 (1.8288 m)




PVC




197






5




5




12 (3.6576 m)




PVC




288






6




6




25 (7.26 m)




PVC




880






7




7




12 (3.6576 m)




Polyurethane + EVA




305






8




8




25 (7.26 m)




Polyurethane + EVA




660














It is evident from Examples 1-8 that telephone cords with 100% polyurethane jackets had a smaller retracted length than telephone cords with PVC jackets.




EXAMPLES 9-16




The retractile telephone cords of Examples 1-8 were expanded and stretched to a maximum extended position as indicated in Table 2 below, without interfering with their ability to return to their normal unstretched retracted position.












TABLE 2











Extended Length



















Ex-






Exam-




Retractile




Total Nominal





tended






ple




Telephone




Uncoiled Length





Length






No.




Cord




(feet)




Outer Protective Jacket




(mm)









 9




1




 6 (1.8288 m)




Polyurethane




1660






10




2




12 (3.6576 m)




Polyurethane




3420






11




3




25 (7.26 m)




Polyurethane




7240






12




4




 6 (1.8288 m)




PVC




1620






13




5




12 (3.6576 m)




PVC




3380






14




6




25 (7.26 m)




PVC




7080






15




7




12 (3.6576 m)




Polyurethane + EVA




3404






16




8




25 (7.26 m)




Polyurethane + EVA




7163














It is evident from Examples 9-16 that telephone cords with 100% polyurethane jackets and with composite jackets of polyurethane and ethylene vinyl acetate (EVA) have a greater extended length than telephone cords with PVC jackets.




EXAMPLES 17-57




Retractile telephone cords were formed and constructed as described in Examples 1-8 and were hung vertically. The top ends of the telephone cords were secured and fixed in a stationary position. Weights were connected and added to the bottoms of the telephone cords to stretch, extend, and expand the telephone cords an additional length of 0.3 m, 1.0 m, 1.2 m, 1.5 m, 1.7 m, and 1.8 m as indicated in Table 3 below. The amount of weights (load) required to stretch, extend and expand the telephone cords to the additional lengths are also shown in Table 3 below.












TABLE 3











Additional Length and Load


















Total Nor-





Addi-







Exam-




Tele-




mal Uncoiled





tional






ple




phone




Length




Outer




Length




Load






No.




Cord




(Feet)




Protective Jacket




(m)




(gm)









17




1




 6 (1.8288 m)




Polyurethane




0.3




 72






18




1




 6 (1.8288 m)




Polyurethane




1.0




180






19




1




 6 (1.8288 m)




Polyurethane




1.2




270






20




2




12 (3.6576 m)




Polyurethane




0.3




 80






21




2




12 (3.6576 m)




Polyurethane




1.0




115






22




2




12 (3.6576 m)




Polyurethane




1.2




140






23




2




12 (3.6576 m)




Polyurethane




1.5




150






24




2




12 (3.6576 m)




Polyurethane




1.7




175






25




2




12 (3.6576 m)




Polyurethane




1.8




180






26




3




25 (7.26 m)




Polyurethane




0.3




110






27




3




25 (7.26 m)




Polyurethane




1.0




150






28




3




25 (7.26 m)




Polyurethane




1.2




152






29




3




25 (7.26 m)




Polyurethane




1.5




155






30




3




25 (7.26 m)




Polyurethane




1.7




160






31




3




25 (7.26 m)




Polyurethane




1.8




165






32




4




 6 (1.8288 m)




PVC




0.3




 70






33




4




 6 (1.8288 m)




PVC




1.0




160






34




5




12 (3.6576 m)




PVC




0.3




 80






35




5




12 (3.6576 m)




PVC




1.0




110






36




5




12 (3.6576 m)




PVC




1.2




140






37




5




12 (3.6576 m)




PVC




1.5




150






38




5




12 (3.6576 m)




PVC




1.7




160






39




5




12 (3.6576 m)




PVC




1.8




165






40




6




25 (7.26 m)




PVC




0.3




110






41




6




25 (7.26 m)




PVC




1.0




145






42




6




25 (7.26 m)




PVC




1.2




150






43




6




25 (7.26 m)




PVC




1.6




155






44




6




25 (7.26 m)




PVC




1.7




160






45




6




25 (7.26 m)




PVC




1.8




165






46




7




12 (3.6576 m)




Polyurethane +




0.3




 80









EVA






47




7




12 (3.6576 m)




Polyurethane +




1.0




130









EVA






48




7




12 (3.6576 m)




Polyurethane +




1.2




140









EVA






49




7




12 (3.6576 m)




Polyurethane +




1.5




150









EVA






50




7




12 (3.6576 m)




Polyurethane +




1.7




180









EVA






51




7




12 (3.6576 m)




Polyurethane +




1.8




185









EVA






52




8




25 (7.26 m)




Polyurethane +




0.3




110









EVA






53




8




25 (7.26 m)




Polyurethane +




1.0




180









EVA






54




8




25 (7.26 m)




Polyurethane +




1.2




150









EVA






55




8




25 (7.26 m)




Polyurethane +




1.5




155









EVA






56




8




25 (7.26 m)




Polyurethane +




1.7




160









EVA






57




8




25 (7.26 m)




Polyurethane +




1.8




165









EVA














EXAMPLES 58-65




Retractile telephone cords were formed and constructed as described in Example 1-8. The top ends of the telephone cords were secured and fixed in a stationary position. Loads (weights) of 170 gm were connected and added to the bottom of the telephone cords for 60 seconds to stretch, extend, and expand the telephone cords to the loaded lengths indicated in Table 4 below:












TABLE 4











Extension Tests















Exam-




Retractile




Total Nominal








ple




Telephone




Uncoiled Length





Loaded






No.




Cords




(Feet)




Outer Protective Jacket




Length









58




1




 6 (1.8288 m)




Polyurethane




 790






59




2




12 (3.6576 m)




Polyurethane




2270






60




3




25 (7.26 m)




Polyurethane




3390






61




4




 6 (1.8288 m)




PVC




1005






62




5




12 (3.6576 m)




PVC




2340






63




6




25 (7.26 m)




PVC




3890






64




7




12 (3.6576 m)




Polyurethane + EVA




1651






65




8




25 (7.26 m)




Polyurethane + EVA




4089














It appears from Examples 58-65 that the loaded lengths of telephone cords with 100% polyurethane jackets and with composite jackets of polyurethane and ethylene vinyl acetate (EVA) are smaller than the loaded lengths of telephone cords with PVC jackets.




EXAMPLES 66-73




Retractile telephone cords were formed and constructed as described in Examples 1-8. The top ends of the telephone cords were secured and fixed in a stationary position. Loads (weights) of 170 gm were hung from the bottoms of the telephone cords for 300 seconds. The loads (weights) were than removed and the bottom ends of the telephone cords moved upwardly as the telephone cords retracted to the recovered lengths indicated in Table 5 below.












TABLE 5











Recovery Tests



















Re-






Exam-




Retractile




Total Nominal





covered






ple




Telephone




Uncoiled Length





Length






No.




Cord




(Feet)




Outer Protective Jacket




(mm)









66




1




 6 (1.8288 m)




Polyurethane




 70






67




2




12 (3.6576 m)




Polyurethane




283






68




3




25 (7.26 m)




Polyurethane




1140 






69




4




 6 (1.8288 m)




PVC




145






70




5




12 (3.6576 m)




PVC




460






71




6




25 (7.26 m)




PVC




1470 






72




7




12 (3.6576 m)




Polyurethane + EVA




305






73




8




25 (7.26 m)




Polyurethane + EVA




660














Examples 66-73 clearly indicate that the recovered lengths of telephone cords with 100% polyurethane jackets and with composite jackets of polyurethane and ethylene vinyl acetate (EVA) are smaller than telephone cords with PVC jackets.




EXAMPLES 74-81




Retractile telephone cords were formed and constructed as described in Examples 1-8. The top ends of the telephone cords were secured and fixed in a stationary position. The telephone cords were each stretch, expanded, and extended to an additional length of 1.2 meters (m) for 30 minutes by adding and connecting appropriate weights to the bottoms of the telephone cords. Afterwards, the loads (weights) were removed and the bottom ends of the telephone cords retracted upwardly. Five minutes after the load (weight) was released and removed, the recovered lengths of the telephone cords were measured. The recovered length of the telephone cords are indicated in Table 6 below.












TABLE 6











Extension and Recovery



















Re-






Exam-




Retractile




Total Nominal





covered






ple




Telephone




Uncoiled Length





Length






No.




Cord




(Feet)




Outer Protective Jacket




(mm)









74




1




 6 (1.8288 m)




Polyurethane




137






75




2




12 (3.6576 m)




Polyurethane




260






76




3




25 (7.26 m)




Polyurethane




670






77




4




 6 (1.8288 m)




PVC




201






78




5




12 (3.6576 m)




PVC




335






79




6




25 (7.26 m)




PVC




910






80




7




12 (3.6576 m)




Polyurethane + EVA




336






81




8




25 (7.26 m)




Polyurethane + EVA




654














As is evident from Examples 74-81, retractile telephone cords with 100% polyurethane jackets and with composite jackets of polyurethane and ethylene vinyl acetate (EVA) have a smaller recovered length than retractile telephone cords with PVC jackets.




EXAMPLES 82-91




Retractile telephone cords of similar lengths were formed and tested with a polyproylene primary insulation and an outer protective jacket comprising different density polyurethane elastomeric secondary insulation. The hardness, modulus, tensile strength, elongation at break, taper abrasion, and brittleness points of the retractile telephone cords are indicated in Table 7 below.












TABLE 7











Retractile Cords With Different Density






Polyurethane Outer Protective Jackets






















Example




No.




82




83




84




85




86




87




88




89




90




91

























Hardness




Shore




80A




85A




90A




95A




98A




80A




85A




90A




95A




98A







A/D






100%




kgf/cm


2






60




80




100




120




150




50




70




90




110




140






Modulus






Tensile




kgf/cm


2






350




380




400




420




440




360




380




420




430




440






Strength






Elongation




%




640




600




550




460




450




650




600




580




520




500






at Break






Taper




mg




30




30




30




25




25




30




30




30




25




25






Abrasion






Brittleness




° C.




<−50




<−50




<−50




<−40




<−40




<−50




<−50




<−50




<−50




<−40






Point














Examples 82-91 indicate that the hardness, modulus, tensile strength, elongation at breaking point, taper abrasion, and brittleness point varied with the type of polyurethane used. Example 85 had the most preferred qualities in Table 7.




In some circumstances, it may be desirable that the primary insulation comprise: polyurethane, polyurethane-diisocyanate, urethane, polyethylene, polyvinyl chloride, polysulfone, polystyrene, neoprene, butadiene, styrene butadiene rubber, vulcanized Hevea, Buna S, butyl rubber, natural rubber (polyisoprene), acrylonitrile-butadiene, silicone, polysiloxane, chlorsulfanated polyethylene, nylon (polyamide), crystalline thermoplastic elastomer, or other plastic insulating material.




Furthermore, in some circumstances, it may be desirable that the outer protective jacket providing the secondary insulation, comprises: polytetrafluoroethylene (PTFE) (Teflon), polypropylene, , polyethylene, polyvinyl chloride, polysulfone, polystyrene, neoprene, butadiene, styrene butadiene rubber, vulcanized Hevea, Buna S, butyl rubber, natural rubber (polyisoprene), acrylonitrile-butadiene, silicone, polysiloxane, chlorsulfanated polyethylene, nylon (polyamide), or other plastic insulating material.




The dielectric constant, power factor, volume resistivity, surface resistivity, and dielectric strength of some of the preceding rubber and elastomeric insulators are shown in Table 8 below.












TABLE 8











Properties of Rubbers and Elastomeric Insulators


















Power










Di-electric




factor X




Volume




Surface




Di-electric







constant,




10


2


, 10


6






resistivity,




resistivity,




strength,






Material




10


6


Hz




Hz




Ω · cm




Ω




V/mil









Natural




2.7-5  




0.05-0.2 




10


15


-10


17






10


14


-10


15






450-600






rubber






Styrene-




2.8-4.2




0.5-3.5




10


14


-10


16






10


13


-10


14






450-600






butadiene






rubber






Acryloni-




 3.9-10.0




3-5




10


12


-10


15






10


12


-10


15






400-500






trile-buta-






diene rubber






Butyl




2.1-4.0




0.3-8.0




10


14


-10


16






10


13


-10


14






400-800






rubber






Chlorosulfo-




 5.0-11.0




2.0-9.0




10


13


-10


17






10


14






400-600






nated poly-






ethylene






Polyurethane




5.0-8.0




3.0-6.0




10


10


-10


11







450-500














The dielectric constants at different frequencies for some of the preceding insulators are shown in Table 9 below.












TABLE 9











Dielectric Constants of Insulators at Different Frequencies













Frequency (Hertz)















Material




° C.




1 × 10


3






1 × 10


6






1 × 10


8











Polyamide resins:










Nylon 66




25




3.75




3.33




3.16






Nylon 610




25




3.50




3.14




3.0 






Polyethylene




−12 




2.37




2.35




2.33







23




2.26




2.26




2.26






Polyvinyl chloride




25




4.55




3.3 






Polystyrene




  2.5




2.54-2.56




2.54-2.56




2.55







80




2.54




2.54




2.54






Hevea, vulcanized




27




2.94




2.74




2.42






Buna S




20




2.66




2.56




2.52






Butyl rubber compound




25




2.42




2.40




2.39






Neoprene




24




6.60




6.26




4.5 






Silicon rubber




25




3.12-3.30




3.10-3.20




3.06-3.18














The dielectric constants and dissipation factors (loss) for some of the preceding insulators are shown in Table 10 below.












TABLE 10











Dielectric Constants and Dissipation Factors of Insulators














Dielectric constant




Dissipation






Material




At 10


6


Hz




Factor at 10


6


Hz









PTFE, (Teflon)




2.0




0.0002-0.0003






Nylon 6 and nylon 10




3.5-3.6




0.04






Polypropylene




2.20-2.28




0.0002-0.002 






Silicones




3.4-4.3




0.001-0.004














The arc resistance, dielectric constants, dissipation factors, dielectric strength, volume resistivity, tensile strength, tensile modulus, elongation, compressive strength, flexural strength, impact strength, hardness, heat distortion, coefficient for thermal expansion, thermal conductivity, and flammability for some of the preceding insulators are shown in Table 11 below.












TABLE 11











Properties of Insulators




















Poly




Poly




Poly












ethylene,




ethylene,




ethylene,







Poly




Tetra







low-




med-




high-




Poly




Poly




Poly




vinyl




fluoro






Material




density




density




density




propylene




styrene




sulfone




chloride




ethylene






















Electrical properties:














Arc resistance




140




200




200




185




100




122




80




>200






Dielectric constant






60 Hz




2.4




2.4




2.4




2.6




3.4




3.1




3.6




2.1






10


6


Hz




2.4




2.4




2.4




2.6




3.2




3.1




3.3




2.1






10


9


Hz




2.4




2.4




2.4




2.6




3.1




3.1




3.4




2.1






Dissipation factor






60 Hz




<0.0005




<0.0005




<0.0005




<0.0005




0.0004




0.0008




0.007




<0.0002






10


6


Hz




<0.0005




<0.0005




<0.0005




<0.0005




0.0004




0.001




0.009




<0.0002






10


9


Hz




<0.0005




<0.0005




<0.0005




<0.0005




0.0004




0.005




0.006




<0.0002






Dielectric strength,




420




500




550




450




300




400




3.75




430






V/mil step by step






Volume resistivity,




10


16






10


16






10


16






10


16






10


16






10


17






10


16






10


18








Ω · cm






Mechanical properties:






Tensile strength, lb/in.


2






2,300




3,500




5,500




5,500




6,800




10,200




9,000




4,500






Tensile modulus, lb/in.


2






0.35




0.55




1.5




2.3




4.5




3.6




6.0




0.58






× 10


5








Elongation, %




800




600




100




700




80




100




40




400






Flexural strength,




7,000




1,000




8,000




10,000




15,400




16,000






lb/in.


2








Impact strength, ft lb/m




No break




>16




20




1.5




8




1.3




20




3.0






of notch






Hardness, Rockwell







R110




R100




R120






Thermal properties:






Heat-distortion temp.




105




120




120




145




205





164




>250






at 264 lb/in


2








Maximum-use temp.,




212




250




250




320




175





175




550






° F.






Coefficient of thermal




18




16




13




10




21




6




18




10






expansion, ° C.


−1


× 10


−5








Thermal conductivity,




8.0




10.0




12.4




2.8




3.0




6.2




7.0




6






cal/S-cm ° C.






Flammability, in./min




1.04




1.04




1.04




1.04




1.0




No burn




No burn




No burn














Among the many advantages of the modular retractile telephone cords of the present invention are:




1. Superior performance.




2. Reduced sagging.




3. Smaller relaxed retracted and recovered lengths.




4. Excellent space saver.




5. Better visual appeal.




6. Simple to install.




7. Easy to use.




8. Less obtrusive.




9. Compact.




10. Convenient.




11. Attractive.




12. User friendly.




13. Strong.




14. Economical.




15. Reliable.




16. Safe.




17. Efficient.




18. Effective.




Although embodiments have been shown and described, it is to be understood that various modifications and substitutions, as well as rearrangements of parts and components, can be made by those skilled in the art, without departing from the normal spirit and scope of this invention.



Claims
  • 1. A telephone cord, comprising:a modular retractile telephone cord having a composite jacket with opposite ends, said composite jacket comprising polyurethane and ethylene vinyl acetate, and said composite jacket comprising said polyurethane and said ethylene vinyl acetate enclosing a core of 2 to 8 conductors electrically insulated and separated by primary insulation, said cord with said composite jacket comprising said polyurethane and said ethylene vinyl acetate having a coiled portion disposed between said ends, and said coiled portion with said composite jacket comprising said polyurethane and said ethylene vinyl acetate including coils; and at least one modular telephone plug, said plug being connected to one of said ends of said modular retractile telephone cord adjacent said composite jacket comprising said polyurethane and said ethylene vinyl acetate.
  • 2. A telephone cord in accordance with claim 1 wherein:said composite jacket comprises by weight 80%-90% polyurethane and 10%-20% ethylene vinyl acetate; said primary insulation comprising an insulating material selected from the group consisting of polypropylene, polyethylene, polyvinyl chloride, neoprene, polyurethane, urethane, butadiene, styrene, natural rubber, polystyrene, polysulfone, vulcanized Hevea, Buna 5, butyl rubber, polyisoprene, styrene-butadiene, acrylonitrile-butadiene, chlorosulfanated polyethylene, silicone, polysiloxane, nylon, and crystalline thermoplastic elastomer; and said modular retractile telephone cord comprises a modular cord selected from the group consisting of a telephone handset cord, a telephone headset cord, a telephone vehicle cord, a telephone computer cord, and a telephone modem cord.
  • 3. A telephone cord in accordance with claim 2 wherein:said composite jacket comprises by weight: 50%-99% polyurethane and 1%-50% ethylene vinyl acetate; and said modular retractile telephone cord is selected from the group consisting of a 6 ft. (1.8288 m) cord, a 12ft. (3.6576 m) cord, and a 25 ft. (7.62 m) cord.
  • 4. A telephone cord in accordance with claim 1 wherein said maximum outside coil diameter is at least one inch (24.5 mm).
  • 5. A telephone cord in accordance with claim 1 wherein said conductors are selected from the group consisting of; flexible conductors comprising tinsel ribbons, substantially parallel strands of wire, and twisted strands; and said composite jacket having a maximum outside diameter greater than 0.75 inches (19.05 mm) and comprising by weight 80%-90% polyurethane and 10%-20% ethylene vinyl acetate.
  • 6. A telephone cord in accordance with claim 1 wherein said composite polyurethane jacket has a coating comprising an elastomeric material.
  • 7. A telephone cord in accordance with claim 1 wherein said coils have substantially the same maximum outside coil diameter.
  • 8. A telephone cord in accordance with claim 1 wherein said coils have different maximum outside coil diameters.
  • 9. A telephone cord, comprising:a retractile telephone cord having opposite ends and a coiled portion positioned between said opposite ends, said coiled portion having spiral coils, said retractile telephone cord comprising; a core comprising 2 to 8 conductors; primary insulation for electrically insulating and separating said conductors, said primary insulation comprising a primary insulating material selected from the group consisting of polypropylene, polyethylene, polyvinyl chloride, neoprene, polyurethane, urethane, butadiene, styrene, natural rubber, polystyrene, polysulfone, vulcanized Hevea, Buna 5, butyl rubber, polyisoprene, styrene-butadiene, acrylonitrile-butadiene, chlorosulfonated polyethylene, silicone, polysiloxane, nylon, and crystalline thermoplastic elastomer; and a composite jacket annularly surrounding said primary insulation and said core, said composite jacket comprising by weight 50%-99% polyurethane and 1%-50% ethylene vinyl acetate.
  • 10. A telephone cord in accordance with claim 9 wherein:said retractile telephone cord comprises a modular cord selected from the group consisting of: a telephone handset cord, a telephone headset cord, a telephone vehicle cord, a telephone computer cord, and a telephone modem cord; and said composite polyurethane jacket comprises 80%-90% polyurethane and 10%-20% ethylene vinyl acetate; and said coils have a maximum outside diameter greater than 0.75 inches (19.05 mm).
  • 11. A telephone cord in accordance with claim 9 wherein:said coils have a maximum diameter greater than one inch (24.5 mm); said conductors are selected from the group consisting of substantially parallel conductors, twisted conductors, and flexible tinsel conductors; and said retractile telephone cord is selected from the group consisting of a 6 ft. (1.8288 mm) cord, a 12 ft. (3.6576 m) cord, and a 25 ft. (7.62 m) cord.
  • 12. A telephone cord in accordance with claim 9 wherein said coils have about the same maximum outside diameter.
  • 13. A telephone cord in accordance with claim 9 wherein said coiled portion comprises a tapered coiled portion with at least some of said coils having a different maximum outside diameter.
  • 14. A telephone cord, comprising:a modular retractile telephone cord having a spiral wound coiled portion extending between ends of said cord, said spiral wound coiled portion having spiral coils with a maximum coil diameter greater than 0.75 inches (19.05 mm); a core comprising 2 to 8 electrical conductors; primary insulation for electrically insulating and separating said conductors, said primary insulation comprising polypropylene; a composite jacket comprising secondary insulation for annularly surrounding said primary insulation and said core, said secondary insulation of said composite jacket comprising by weight: 50%-99% polyurethane and 1%-50% ethylene vinyl acetate; and said modular retractile telephone cord having a maximum coil diameter greater than 0.75 inches (19.05 mm) and comprising a modular cord selected from the group consisting of a telephone handset cord, a telephone headset cord, a telephone vehicle cord, a telephone computer cord, and a telephone modem cord; and at least one modular telephone plug, said modular telephone plug having said maximum coil diameter greater than 0.75 inches (19.05 mm) being connected to one of the ends of said modular retractile telephone cord.
  • 15. A telephone cord in accordance with claim 14 wherein:said composite polyurethane jacket comprises by weight: 80%-90% polyurethane and 10%-20% ethylene vinyl acetate; said electrical conductors are selected from the group consisting of substantially parallel tinsel conductors and twisted conductors; and said modular retractile telephone cord having said maximum coil diameter greater than 0.75 inches (19.05 mm) is selected from the group consisting of a 12 ft. (3.6576 m) cord and a 25 ft. (7.62 m) cord.
  • 16. A telephone cord in accordance with claim 14 wherein said modular retractile telephone cord comprises a telephone handset cord with a second modular telephone plug connected to the other end of said cord.
  • 17. A telephone cord in accordance with claim 14 wherein said spiral coils have a maximum coil diameter of at least one inch (24.5 mm).
  • 18. A telephone cord in accordance with claim 14 wherein said coils comprise substantially uniform helical coils with substantially the same maximum coil diameter.
  • 19. A telephone cord in accordance with claim 14 wherein:said spiral wound coil portion comprises a tapered portion; at least some of said spiral coils in said tapered portion have a different maximum coil diameter; and said modular retractile telephone cord has an external elastomeric layer covering at least a portion of said composite jacket comprising by weight 50%-99% polyurethane and 1%-50% ethylene vinyl acetate.
  • 20. A telephone cord, comprising:a telephone handset cord for connecting a telephone handset to a base unit, said telephone handset cord comprising a modular retractile telephone cord with a handset-facing end, a base-facing end, and a spiral wound coiled portion extending between said ends, said spiral wound coiled portion comprising spiral coils; a telephone handset connector comprising a handset-connecting modular plug connected to said handset-facing end of said telephone handset cord for connection to a telephone handset; a base connector comprising a base-connecting modular plug connected to said base-facing end of said telephone handset cord for connection to a base unit; said telephone handset cord being biased in a normally relaxed retracted position when the handset is cradled or seated on the base unit; said telephone handset cord being expandable to an elongated stretched extended position when the handset is moved away from the base unit; said telephone handset cord having a retracted length in the retracted position and an extended length in the extended position; said spiral coils having a greater maximum coil diameter and being positioned closer together when said telephone handset cord is in said retracted position; said spiral coils have a maximum coil diameter greater than 0.75 inches (19.05 mm) when said telephone handset cord is in said retracted position; said telephone handset cord comprising a cordage assembly with a core comprising 4 to 8 substantially parallel electrical conductors selected from the group consisting of wire, strands, and a flexible tinsel ribbon; primary insulation for electrically insulating and separating said electrical conductors, said primary insulation comprising polypropylene; and a composite jacket comprising secondary insulation for annularly surrounding and enclosing said primary insulation and said core, said secondary insulation of said composite jacket comprising elastomeric insulating materials comprising by weight about 80%-90% polyurethane and about 10%-20% ethylene vinyl acetate, and said composite polyurethane jacket has a wall thickness greater than 0.1 inches (2.54 mm) and a tensile strength greater than 1200 psi (84,368,35 g/cm2).
  • 21. A telephone cord is accordance with claim 20 wherein the extended length is greater than 5 times the retracted length of said telephone handset cord.
  • 22. A telephone cord is accordance with claim 20 wherein the retracted length is less than 15% of the extended length of said telephone handset cord.
  • 23. A telephone cord is accordance with claim 20 wherein said conductors comprise 26-28 AWG wire.
  • 24. A telephone cord is accordance with claim 20 wherein:each of said conductors have a diameter ranging from 0.015 inches (0.38 mm) to 0.024 inches (0.61 mm); and said telephone handset cord has a nominal uncoiled total length of 6 feet (1.8288 m), 12 feet (3.6576 m), or 25 feet (7.62 m).
  • 25. A telephone cord is accordance with claim 20 wherein said coils comprise substantially uniform helical coils with substantially the same maximum coil diameter when said telephone handset cord is in said retracted position.
  • 26. A telephone cord is accordance with claim 20 wherein:said spiral wound coiled portion comprises a tapered portion; and at least some of said spiral coils in said tapered portion have different maximum coil diameters when said telephone handset cord is in said retracted position.
  • 27. A telephone cord is accordance with claim 20 wherein said spiral coils have a maximum coil diameter of at least 0.75 inches (19.05 mm) when said telephone handset cord is in said retracted position.
  • 28. A telephone cord in accordance with claim 20 wherein said spiral coils have a maximum coil diameter of at least one inch (24.5 mm) when said telephone handset cord is in said retracted position.
RELATED APPLICATIONS

This application is a continuation-in-part of U.S. Application Ser. No. 09/135,372 filed Aug. 17, 1998 of Jeffrey M. Morris and Yong R. Chu for Modular Retractile Telephone Cords, presently assigned to Group Art Unit 2831.

US Referenced Citations (19)
Number Name Date Kind
1937981 Rosenthal Dec 1933
2704782 Ames Mar 1955
2795641 Rowell Jun 1957
3854002 Glander et al. Dec 1974
3993860 Snow et al. Nov 1976
4227042 Lueddecke et al. Oct 1980
4346145 Choi et al. Aug 1982
4375012 Cocco et al. Feb 1983
4490575 Kutnyak Dec 1984
4551185 Loesch Nov 1985
4582867 Choi et al. Apr 1986
4592955 Choi et al. Jun 1986
4656091 Choi et al. Apr 1987
4683349 Takebe Jul 1987
4705823 Choi et al. Nov 1987
4910359 Dougherty et al. Mar 1990
5087521 Choi et al. Feb 1992
5340652 Sondhe et al. Aug 1994
5635559 Brock et al. Jun 1997
Foreign Referenced Citations (2)
Number Date Country
1 229 442 Apr 1971 GB
1311118 Mar 1973 GB
Continuation in Parts (1)
Number Date Country
Parent 09/135372 Aug 1998 US
Child 09/235616 US