Communication system and communication cable connector assembly

Information

  • Patent Grant
  • 6299490
  • Patent Number
    6,299,490
  • Date Filed
    Wednesday, August 9, 2000
    23 years ago
  • Date Issued
    Tuesday, October 9, 2001
    22 years ago
Abstract
A communication cable connector assembly includes a first connector, a second connector and a first breakout connector. The first connector has a plurality of first terminals. The second connector has a plurality of second terminals with a plurality of adjacent pairs of terminals. Each of the plurality of second terminals mate with a corresponding one of the plurality of first terminals. A plurality of the adjacent pairs of terminals define breakout terminal pairs which are non-adjacent relative to each other. A first breakout connector associated with the second connector has a plurality of third terminals associated with the breakout terminal pairs of the second connector.
Description




BACKGROUND OF THE INVENTION




1. Field of the Invention




The present invention relates to electrical connectors, and, more particularly, to communication cable connectors for use with local area networks and/or telephones.




2. Description of the Related Art




Wiring systems for use in modular office systems, such as for use in modular wall partitions and furniture, typically are formed as modular systems with discrete electrical components which interconnect in a plurality of configurations. Such a wiring system may be used to provide electrical power and/or communication signals to a work space. The communication signals may correspond to voice (i.e., telephone) signals and/or data (i.e., local area network or computer modem) signals.




A wiring arrangement for providing communication signals in the form of telephone and/or data signals is described in U.S. Pat. No. 5,160,276 (Marsh, et al.), which has been reassigned to the assignee of the present invention. Disclosed thereby is a wiring arrangement in which a male and female mating connector pair associated with each workstation includes breakout terminal pairs for an RJ-45 connector arranged in a stepped manner from one workstation to another. The RJ-45 connector is connected via a jumper cable to a corresponding access port in a face plate mounted to an exposed surface within the workstation. The access port may be, e.g., another RJ-45 connector in the face place. The stepped wiring arrangement allows the same terminal pairs of each associated mating connector to be connected with the RJ-45 connector. In particular, the RJ-45 connector includes 4 terminal pairs (i.e., eight terminals) which are respectively connected with terminals


1


-


8


of an associated mating connector. The four terminal pairs, i.e., terminals


1


-


8


, are disposed side-by-side relative to each other within the mating connector.




Although U.S. Pat. No. 5,160,276 (Marsh, et al.), is clearly a step forward in the art, the present inventors have recognized that still further improvements can be made. To wit, industry standards require that crosstalk between adjacent wire pairs be maintained at or below a predetermined level. Each wire pair is typically provided as a twisted wire pair, with the twist functioning to substantially eliminate crosstalk with an adjacent wire pair. However, at the points where the wires of each wire pair are connected with the terminals of the mating connector, the wires must necessarily be untwisted to allow for attachment with the associated terminals. At the attachment points with the mating connector, the wires are no longer twisted and the probability for crosstalk to occur increases. Moreover, to reduce the physical size of the connector, the spacing between adjacent terminals is maintained as small as possible and typically is only a few thousandths of an inch. Since the four twisted wire pairs are sequentially attached to eight adjacent terminals in a row of terminals of the connector, and since the terminals are maintained as close as possible to each other to reduce the physical size of the mating connector, crosstalk between adjacent wire pairs may occur to some extent.




What is needed in the art is a communication system for voice and/or data signals which not only allows for the efficient breakout of terminal pairs for an RJ-45 connector associated with each mating connector pair of a workstation, but also effectively reduces crosstalk between adjacent terminals and twisted wire pairs.




SUMMARY OF THE INVENTION




The present invention provides a communication cable connector assembly having breakout terminal pairs which are positioned non-adjacent relative to each other to thereby minimize crosstalk between twisted wire pairs.




The invention comprises, in one form thereof, a communication cable connector assembly including a first connector, a second connector and a first breakout connector. The first connector has a plurality of first terminals. The second connector has a plurality of second terminals with a plurality of adjacent pairs of terminals. Each of the plurality of second terminals mate with a corresponding one of the plurality of first terminals. A plurality of the adjacent pairs of terminals define breakout terminal pairs which are non-adjacent relative to each other. A first breakout connector associated with the second connector has a plurality of third terminals associated with the breakout terminal pairs of the second connector.




An advantage of the present invention is that crosstalk between twisted wire pairs in the communication system is minimized.




Another advantage is that the connectors are wired with a stepped pinout sequence which provides predetermined locations for the breakout terminal pairs within the mating connector.











BRIEF DESCRIPTION OF THE DRAWINGS




The above-mentioned and other features and advantages of this invention, and the manner of attaining them, will become more apparent and the invention will be better understood by reference to the following description of embodiments of the invention taken in conjunction with the accompanying drawings, wherein:





FIG. 1

is a perspective view of a communication connector assembly of the present invention including a male and female connector in a disassembled state;





FIGS. 2 and 3

illustrate an embodiment of a pinout arrangement of a communication system of the present invention using the communication connector assembly of

FIG. 1

;





FIG. 4

illustrates one embodiment of a layout of the communication system of

FIGS. 2 and 3

including six breakouts; and





FIG. 5

is a schematic illustration of another embodiment of a pinout arrangement of a communication system of the present invention.











Corresponding reference characters indicate corresponding parts throughout the several views. The exemplifications set out herein illustrate one preferred embodiment of the invention, in one form, and such exemplifications are not to be construed as limiting the scope of the invention in any manner.




DETAILED DESCRIPTION OF THE INVENTION




Referring now to the drawings, and more particularly to

FIGS. 1-4

, there is shown an embodiment of a communication system


110


of the present invention (FIGS.


2


and


4


), including an embodiment of a communication cable connector assembly


112


of the present invention (FIGS.


1


-


4


).




Communication cable connector assembly


112


(

FIG. 1

) includes a first connector


114


, a second connector


116


and a first breakout connector


118


. First connector


114


and second connector


116


are configured to mate together, as will be described in further detail hereinafter.




First connector


114


includes a plurality of first terminals which are arranged in two longitudinal rows of terminals which are laterally adjacent to each other, one row of which is visible in FIG.


1


and referenced as


120


. The one row of first terminals


120


are arranged on an inside wall of a projection


122


having keys


124


. The opposing row of first terminals (not visible) are arranged on the opposite and substantially parallel inside wall of projection


122


. First terminals


120


are arranged in a plurality of adjacent pairs of terminals, such as terminal pair


120


A, with the two terminals of each terminal pair being respectively connected with a corresponding two wires of a twisted wire pair in a plurality of twisted wire pairs (not shown in

FIG. 1

) carried within cable


126


.




Second connector


116


includes a plurality of second terminals which are arranged in two longitudinal and laterally adjacent rows of terminals, one row of which is referenced as


128


in FIG.


1


. Second terminals


128


are mounted in two substantially parallel rows on opposite sides of a center projection


130


. Center projection


130


, with second terminals


128


mounted thereon, in turn is surrounded by a wall


132


with keys


134


. When first connector


114


and second connector


116


are plugged together, center projection


130


fits within the opening defined by projection


122


such that first terminals


120


engage respective second terminals


128


. Wall


132


surrounds projection


122


, with keys


134


fitting within keys


124


.




Second terminals


128


are arranged in a plurality of adjacent pairs of terminals, such as terminal pair


128


A in FIG.


1


. The individual terminals of each terminal pair are connected with corresponding wires of a twisted wire pair in a plurality of twisted wire pairs (not shown in

FIG. 1

) carried within cable


136


. The two terminals of each terminal pair, such as terminal pair


128


A, are arranged longitudinally adjacent to each other within the two rows of second terminals


128


.




First breakout connector


118


, in the embodiment shown, is in the form of an RJ-45 connector allowing connection of an appropriate electrical device, such as a telephone or computer, with communication cable connector assembly


112


. For example, a face plate


164


(

FIG. 4

) having a similar RJ-45 connector may be provided within an exposed surface in the workstation, and a patch cable


166


may be used to interconnect the RJ-45 connector at the face plate with RJ-45 connector


118


of second connector


116


located within a modular office partition associated with the workstation. RJ-45 connector


118


includes a plurality of third terminals which are connected with corresponding terminal pairs


128


A of second connector


116


. In the embodiment shown, RJ-45 connector


118


includes eight third terminals


138


which are respectively connected with four terminal pairs


128


A of second connector


116


. RJ-45 connector


118


and second connector


116


are each carried by a common housing


140


for purposes of compactness and neatness.




Referring now to

FIGS. 2 and 3

, conjunctively, a pinout arrangement of the pins or terminals


120


and


128


of first connector


114


and second connector


116


, respectively, will be described in greater detail. First connector


114


and second connector


116


each include fifty pins or terminals, with each individual terminal being respectively referenced


1


-


50


in

FIGS. 2 and 3

. Terminals


25


and


50


of each connector are unused in the illustrated embodiment. The lines interconnecting first connector


114


and second connector


116


in

FIG. 3

illustrate the stepping sequence for the four separate arrays of terminals associated with each breakout terminal pair, as will be described in more detail hereinafter.




Communication cable connector assemblies


112


, individually referenced


112


A and


112


B in

FIG. 2

, correspond to locations at which a user desires to connect with communication system


110


. Communication cable connector assemblies


112


A and


112


B may be located within a single workstation, or may be located within different workstations within the office environment. Communication cable connector assembly


112


A, including first connector


114


A and second connector


116


A is connected with a voice/data bus


142


which carries voice and/or data signals. Voice/data bus


142


may be located, e.g., within an access closet within the office environment. Voice/data bus


142


is connected with first connector


114


A via respective twisted wire pairs


144


, one of which is individually referenced


144


A. Twisted wire pair


144


A (the white/blue twisted wire pair in

FIG. 3

) is connected with terminals


1


and


2


of first connector


114


A. The next twisted wire pair (white/gray) is connected with terminals


3


and


4


, the next twisted wire pair (red/brown) is connected with terminals


5


and


6


, and so on with the last wire pair


144


B (black/orange) being connected with terminals


48


and


49


. When mated together, terminals


1


-


50


of connector


114


A contact with terminals


1


-


50


of second connector


116


A.




The pinout arrangement of second connector


116


A provides both a stepped wiring arrangement between communication cable connector assemblies


112


A and


112


B, as well as reduced crosstalk between adjacent breakout terminal pairs. More particularly, second connector


116


A includes


24


pairs of terminals associated with terminals


1


-


24


and


26


-


49


, with terminals


25


and


50


being unused. The first terminal pair


146


is associated with terminals


1


and


2


, the second terminal pair is associated with terminals


3


and


4


and so on, with the last terminal pair being associated with terminals


48


and


49


. The particular terminal pairs which are connected with RJ-45 connector


118


A are referred to as breakout terminal pairs, with each of the breakout terminal pairs being connected via a corresponding twisted wire pair with the eight terminals of RJ-45 connector


118


A.




In contrast with the wiring arrangement described in U.S. Pat. No. 5,160,276 (Marsh, et al.), which includes breakout terminal pairs which are disposed sequentially longitudinally adjacent to each other within a single row of terminals, the breakout terminal pairs of second connector


116


A are spaced apart from each other both longitudinally (i.e., within the same row of terminals) as well as laterally (from one row of terminals to another). More particularly, a first breakout terminal pair


146


corresponds to terminals


1


and


2


; a second breakout terminal pair


148


corresponds to terminals


13


and


14


; a third break out terminal pair


150


corresponds to terminals


32


and


33


; and a fourth breakout terminal pair


152


corresponds to terminals


44


and


45


. First breakout terminal pair


146


is connected via a twisted wire pair


154


with two corresponding terminals of RJ-45 connector


118


A; second breakout terminal pair


148


is connected via twisted wire pair


156


with two corresponding terminals of RJ-45 connector


118


A; third breakout terminal pair


150


is connected via twisted wire pair


158


with two corresponding terminals of RJ-45 connector


118


A; and fourth breakout terminal pair


152


is connected via twisted wire pair


160


with two corresponding terminals of RJ-45 connector


118


A. Breakout terminal pairs


146


,


148


,


150


and


152


may be selectively used in any desired combination to transmit voice and/or data signals to an associated RJ-45 connector


118


.




Since the spacing between adjacent terminals within the same longitudinal row of terminals is much smaller than the spacing between laterally adjacent terminals in different rows, it has been found that separating the breakout terminal pairs within the same row of terminals is the most important design criteria for reducing crosstalk. However, separating the breakout terminal pairs in a lateral direction between adjacent rows of terminals has also been found to provide improved reduced crosstalk. Thus, although it is possible that third breakout terminal pair


150


could correspond to terminals


26


and


27


because of the larger distance in the lateral direction between terminals


1


,


2


and


26


,


27


, improved reduced crosstalk may be provided by positioning the breakout terminal pairs such that they are neither laterally nor longitudinally adjacent relative to each other.




The interconnection between each second connector


116


and a following first connector


114


is a modified, stepped arrangement. That is, the interconnection between terminal pairs of a second connector


116


with the terminal pairs of a following first connector


114


is such that the same breakout terminal pairs are used on each second connector


116


for connection with a corresponding first breakout connector


118


. However, the terminal pairs do not merely step up or down a distance corresponding to one pair for each breakout of second connector


116


. Rather, the interconnections between terminal pairs of a second connector


116


with a following first connector


114


are a modified, stepped wiring arrangement which is consistent from one communication cable connector assembly


112


to another such that the same breakout terminal pairs are used in association with each breakout connector


118


.




First connector


114


A is connected via twisted wire pairs


144


with voice/data bus


142


as shown in FIG.


3


. More particularly, terminals


1


,


2


are connected with the white/blue twisted wire pair; terminals


3


,


4


are connected with the white/gray twisted wire pair; terminals


5


,


6


are connected with the red/brown twisted wire pair; terminals


7


,


8


are connected with the black/green twisted wire pair; terminals


9


,


10


are connected with the yellow/orange twisted wire pair; and terminals


11


,


12


are connected with the violet/blue twisted wire pair. Twisted wire pair


144


A therefore corresponds to a white/blue twisted wire pair. Terminals


1


-


12


of first connector


114


A are of course connected with respective terminals


1


-


12


of second connector


116


A. Terminals


11


,


12


of second connector


116


A are connected via a yellow/orange twisted wire pair with terminals


9


,


10


of first connector


114


B. Terminals


11


,


12


of second connector


116


A are therefore connected in a stepped up fashion with terminals


9


,


10


of first connector


114


B. Voice or data signals which were originally transmitted over the violet/blue twisted wire pair connected to terminals


11


,


12


of first connector


114


A are therefore transmitted over terminals


9


,


10


of first connector


114


B. Thus, aside from the feeder cable


144


which interconnects voice/data bus


142


with first connector


114


A, the violet/blue twisted wire pair is no longer used in communication system


10


.




The stepped up interconnection between second connector


116


A and first connector


114


B also is carried out for the five other terminal pairs associated with terminals


1


-


10


. For example, the yellow/orange twisted wire pair connected with terminals


9


,


10


of first connector


114


A are coupled in a stepped up fashion with terminals


7


,


8


of first connector


114


B via the black/green twisted wire pair interconnecting terminals


9


,


10


of second connector


116


A with terminals


7


,


8


of first connector


114


B. Similarly, the white/gray twisted wire pair connected with terminals


3


,


4


of first connector


114


A is coupled with terminals


1


,


2


of first connector


114


B via the white/blue twisted wire pair interconnecting terminals


3


,


4


of second connector


116


A with terminals


1


,


2


of first connector


114


B.




The stepping sequence for terminals


13


-


24


associated with breakout terminal pair


148


is similar to that described above with reference to breakout terminal pair


146


, and thus will not be described in detail.




For the third breakout terminal pair


150


associated with terminals


32


and


33


of second connector


116


A, the stepping sequence is slightly different. To wit, breakout terminal pair


32


,


33


of second connector


116


A are connected with terminal pair


32


,


33


of first connector


114


A, which in turn is connected with a white/green twisted wire pair


144


in the feeder cable


144


between voice/data bus


142


and first connector


114


A. At the second communication cable connector assembly


112


B associated with second breakout connector


118


B, terminals


32


and


33


of second connector


116


B are coupled with the red/orange twisted wire pair


144


through the stepped up connection with the white/green twisted wire pair between terminals


34


,


35


of second connector


116


A and terminals


32


,


33


of first connector


114


B. At the fourth workstation


112


D (FIG.


4


), breakout terminals


32


,


33


of second connector


116


D are connected with the black/gray twisted wire pair


144


originally connected with terminal pair


26


,


27


of first connector


114


A. Similarly, at the sixth and last workstation


112


F in communication system


10


, breakout terminal pair


32


,


33


of the second connector


116


F is coupled with the violet/green twisted wire pair


144


connected with terminals


30


,


31


of first connector


114


A.




The stepping sequence for terminals


38


-


49


associated with breakout terminal pair


152


is similar to that described above with reference to breakout terminal pair


150


, and thus will not be described in detail.





FIG. 4

is a simplified illustration of one embodiment of the communication system


110


of the present invention including six communication cable connector assemblies


112


A-


112


F corresponding to six breakout locations designated by a user. The length of each electrical cable with the twisted wire pairs therein which interconnect a second connector


116


at one breakout location with a first connector


114


of another breakout location of course may vary depending upon the particular application. Second connector


116


F is slightly different from the remaining second connectors


116


A-


116


E, in that second connector


116


F is for use with the last breakout location and therefore is not attached with twisted wire pairs in an electrical cable.




Although the embodiment of communication system


110


shown in

FIGS. 2-4

includes a specified number of workstations with a predetermined number of breakout connectors, breakout terminal pairs and stepping sequence for each connector pair, it is also to be appreciated that the number of workstations, breakout connectors at each workstation, breakout terminal pairs associated with each breakout connector and/or stepping sequence of each connector pair may vary for the particular application with which communication system


110


is used. Regardless of the particular application, communication system


110


has a wiring arrangement with a modified stepped sequence wherein the breakout terminal pairs are spaced apart from each other at least within the same row, and preferably also between rows, to reduce crosstalk between breakout terminal pairs.




Referring now to

FIG. 5

, there is shown a schematic illustration of another embodiment of a wiring arrangement for a communication cable connector assembly


170


for use with a communication system of the present invention. Communication cable connector assembly


170


includes a female, first connector


172


and a male, second connector


174


. Second connector


174


includes four breakout terminal wire pairs associated with a first breakout connector in the form of an RJ-45 connector, similar to breakout connector


118


shown with reference to communication system


110


described with reference to

FIGS. 2-4

. However, first connector


172


also includes four breakout terminal pairs associated with a second breakout connector in the form of an RJ-45 connector. Thus, each workstation of the communication system including communication cable connector assembly


170


includes two breakout connectors for use by the user. One of the breakout connectors may be used, e.g., for voice signals and the other breakout connectors may be used, e.g., for computer data signals.




First connector


172


and second connector


174


include fifty terminals each which are divided into four separate arrays of terminals. The four arrays of terminals are respectively associated with a breakout terminal pair of the RJ-45 connector associated with each communication cable connector


170


. Each array of terminals has a stepping sequence which is the same for each communication cable connector assembly


170


within the communication system. The lines extending between first connector


172


and second connector


174


again represent the stepping sequence of the twisted wire pairs used in the wiring arrangement of communication cable connector assembly


170


. In the particular embodiment shown in

FIG. 5

, the communication system may include a maximum of three workstations with two breakout connectors per workstation and four breakout terminal pairs associated with each breakout connector.




First connector


172


and second connector


174


each include a first array of terminals


1


-


10


associated with two respective and separate blue/orange twisted wire pairs which are in turn associated with two separate RJ-45 connectors. For the first workstation, the white/blue twisted wire pair extending from the voice/data bus is spliced directly to the blue/orange twisted wire pair of the RJ-45 connector. Between the first and second workstations, the white/blue twisted wire pair associated with terminals


3


,


4


of second connector


174


is again spliced with the blue/orange twisted wire pair of the RJ-45 connector of first connector


172


. Thus, signals originally transmitted over the red/brown twisted wire pair from the voice/data bus are stepped up to be connected with the blue/orange twisted wire pair at the second workstation. Similarly, signals transmitted over the yellow/orange twisted wire pair from the voice/data bus are stepped up to terminals


3


,


4


of a first connector


172


at the second workstation through the interconnection with the red/brown twisted wire pair. Accordingly, at the third workstation, signals originally transmitted over the yellow/orange twisted wire pair from the voice/data bus are connected with the blue/orange twisted wire pair at the third workstation. For the RJ-45 connector of the second connector


174


of each of the three workstations, it will be appreciated that the stepping sequence shown provides respective interconnection with the signals transmitted over the white/gray, black/green and violet/blue twisted wire pairs from the voice/data bus.




The stepping sequence for the second array of terminals associated with the two black/red twisted wire pairs of each RJ-45 connector is substantially the same as that described above with reference to terminals


1


-


10


, and thus will not be described in detail.




Using the same logic as described above, the stepping sequence for the two breakout terminal pairs associated with the two green/yellow twisted wires of the two RJ-45 connectors, as well as the breakout terminal pairs associated with the brown/gray twisted wires of the two RJ-45 connectors may be easily ascertained. To wit, signals transmitted over white/green, black/blue and yellow/brown twisted wire pairs from the voice/data bus are respectively connected with the green/yellow twisted pair of the RJ-45 connector associated with each respective first connector


172


of the communication system. Similarly, signals transmitted over the red/orange, black/gray and violet/green twisted wire pairs from the voice/data bus are respectively connected with the green/yellow twisted wire pair of the RJ-45 connector associated with each respective second connector of the communication system.




A similar stepping sequence is shown for the last array of terminals associated with the two brown/gray twisted wire pairs, and will not be described in further detail.




While this invention has been described as having a preferred design, the present invention can be further modified within the spirit and scope of this disclosure. This application is therefore intended to cover any variations, uses, or adaptations of the invention using its general principles. Further, this application is intended to cover such departures from the present disclosure as come within known or customary practice in the art to which this invention pertains and which fall within the limits of the appended claims.



Claims
  • 1. A communication cable connector assembly, comprising:a first connector having a plurality of first terminals; a second connector having a plurality of second terminals with a plurality of adjacent pairs of terminals, each of said plurality of second terminals mating with a corresponding one of said plurality of first terminals, a plurality of said adjacent pairs of terminals defining breakout terminal pairs, at least a plurality of said breakout terminal pairs being non-adjacent relative to each other; and a first breakout connector associated with said second connector, said first breakout connector having a plurality of third terminals connected with said breakout terminal pairs of said second connector.
  • 2. The communication cable connector assembly of claim 1, wherein said plurality of first terminals include a plurality of adjacent pairs of terminals, a plurality of said adjacent pairs of terminals of said first connector defining breakout terminal pairs which are non-adjacent relative to each other, and further comprising a second breakout connector having a plurality of fourth terminals connected with said breakout terminal pairs of said first connector.
  • 3. The communication cable connector assembly of claim 1, wherein said plurality of second terminals are arranged in two longitudinal rows of terminals, said two rows of terminals being laterally adjacent to each other, each said adjacent pair of terminals being a longitudinally adjacent pair of terminals.
  • 4. The communication cable connector assembly of claim 1, wherein said plurality of second terminals are arranged in two longitudinal rows of terminals, said two rows of terminals being laterally adjacent to each other, said breakout terminal pairs consisting of four breakout terminal pairs, two of said breakout terminal pairs being in one of said two rows of terminals and a remaining two of said breakout terminal pairs being in an other of said two rows of terminals.
  • 5. The communication cable connector assembly of claim 4, wherein each said adjacent pair of terminals is a longitudinally adjacent pair of terminals, and wherein said breakout terminal pairs within each said row are spaced a substantially equal distance apart.
  • 6. The communication cable connector assembly of claim 5, wherein said plurality of second terminals consist of fifty terminals, and wherein said breakout terminal pairs are spaced apart a distance corresponding to approximately six terminals in the longitudinal direction.
  • 7. The communication cable connector assembly of claim 4, wherein said two breakout terminal pairs located in said one row of terminals are not laterally adjacent to said two breakout terminal pairs located in said other row of terminals.
  • 8. The communication cable connector assembly of claim 1, wherein said plurality of second terminals are arranged in at least one longitudinal row of terminals, said plurality of second terminals being divided into a plurality of arrays of terminals which are longitudinally adjacent to each other, each said array including a plurality of said adjacent pairs of terminals, each said breakout terminal pair being in a different one of said plurality of arrays.
  • 9. The communication cable connector assembly of claim 1, further comprising a plurality of twisted wire pairs, each of said twisted wire pairs being associated with a respective said adjacent pair of terminals.
  • 10. The communication cable connector assembly of claim 1, wherein said plurality of third terminals of said first breakout connector define a plurality of terminal pairs, each said terminal pair of said first breakout connector being connected with a respective said breakout terminal pair of said second connector.
  • 11. The communication cable connector assembly of claim 1, wherein said first breakout connector comprises an RJ-45 connector.
Parent Case Info

This is a continuation of application Ser. No. 09/028,135 filed Feb. 23, 1998 now U.S. Pat. No. 6,102,745.

US Referenced Citations (11)
Number Name Date Kind
504464 Balsley Sep 1893
4829564 Jarvis May 1989
5149277 LeMaster Sep 1992
5160276 Marsh et al. Nov 1992
5586914 Foster, Jr. et al. Dec 1996
5596169 Baker et al. Jan 1997
5618185 Aekins Apr 1997
5651701 Chen Jul 1997
5679027 Smith Oct 1997
5719933 Welch Feb 1998
6102745 Schultz et al. Aug 2000
Continuations (1)
Number Date Country
Parent 09/028135 Feb 1998 US
Child 09/637126 US