Modular electrical plug including a printed circuit substrate

Information

  • Patent Grant
  • 6354865
  • Patent Number
    6,354,865
  • Date Filed
    Thursday, December 17, 1998
    26 years ago
  • Date Issued
    Tuesday, March 12, 2002
    22 years ago
Abstract
An electrical connector which incorporates a printed circuit substrate to accurately modify electrical signals on the cable terminated in the connector. The connector utilizes two distinct sets of contact terminals, the first set acting to terminate the cable and the substrate, the second set acting to terminate the substrate and couple the signals thereon to a mating external jack. The substrate includes circuit components electrically connected between the first and second sets of contact terminals.
Description




BACKGROUND OF THE INVENTION




I. Field of the Invention




The present invention relates to electrical connectors and, more particularly, is directed towards a modular telephone plug type of electrical connector.




II. Description of Related Art




In my prior U.S. Pat. No. 4,412,715, I describe a standard modular plug of the type commonly used in both telephone equipment and other cable interconnect applications. My earlier '715 patent is directed towards a thin, flexible substrate that is positioned within the plug which includes at least one conductive path positioned on the substrate adjacent to one or more of the insulated conductors terminated by the plug. An insulation-piercing contact terminal pierces a segment of the path on the substrate, as well as one of the insulated conductors, to provide electrical connections thereto.




In one embodiment, illustrated in

FIG. 7

of the '715 patent, there is described a U-shaped conductive path 172 that includes a longitudinal segment positioned under one insulated conductor, another longitudinal segment positioned under another insulated conductor, and a transverse segment connecting the two longitudinal segments. I teach that an electrical or electronic component 186 may be included in the transverse segment, and that such component may be an active device (e.g., a transistor, integrated circuit, microprocessor, etc.) or a passive device (e.g., resistor, etc.). It is disclosed in column 9 between lines 9 and 45 that a signal from one contact terminal 156 must travel through the electrical component 186 before reaching the other contact terminal 166. Each of the contact terminals pierce a respective one of the longitudinal segments and its associated insulated conductor.




While the above-described configuration is useful, I have found it to be quite limited in that each of the relevant contact terminals terminate both the insulated conductors and the conductive paths of the printed circuit, such that the electrical component 186 can only indirectly alter or filter the signal. If, for example, electrical signals appear on both of the insulated conductors 138 and 148 that are terminated by the respective contact terminals 156 and 166, electrical component 186 will act on both such signals simultaneously. Further, the precise manner in which component 186 acts on such signals is somewhat unpredictable, and it depends on the signals themselves and their relationship to each other at any given point in time.




It may therefore be appreciated that it would be highly desirable if an arrangement could be devised whereby alteration of the signal appearing on an insulated conductor in the plug could be more carefully and precisely controlled. It is towards this end that the present invention is advanced.




OBJECTS AND SUMMARY OF THE INVENTION




It is therefore a primary object of the present invention to provide a new and improved electrical connector which utilizes a printed substrate in such a manner so as to more accurately and precisely control the alteration of a signal received by the cable terminated in the connector.




Another object of the present invention is to provide a new and improved version of a modular electrical plug having a conductive path over that described in my prior U.S. Pat. No. 4,412,715.




Yet another object of the present invention is to provide a novel and unique electrical connector which incorporates a flexible substrate having a printed circuit pattern and electrical components thereon, in such a manner so as to achieve more precise signal modification in a predetermined manner.




The foregoing and other objects are achieved in accordance with one aspect of the present invention through the provision of an electrical connector, which comprises a dielectric housing, a plurality of insulated conductors positioned in the housing, and a thin flexible substrate positioned in the housing adjacent to the insulated conductors and having a plurality of pairs of electrically conductive sectors thereon. There is further provided insulation-piercing contact terminal means positioned in the housing for making electrical contact with at least one of the insulated conductors and at least one of the pairs of segments and for permitting an electrical connection to be made thereto externally of the housing.




In accordance with more specific aspects of the present invention, the thin, flexible substrate further includes a plurality of electrical components, each of which is connected between a pair of electrically conductive segments so as to modify the electrical signals passing therethrough.




In accordance with more specific aspects of the present invention, the insulation-piercing contact terminal means comprises first and second substantially planar contact terminals positioned in the housing in substantially the same plane. Each of the plurality of pairs of electrically conductive segments includes first and second discrete segments, the first contact terminal making electrical contact with one of the insulated conductors and the first discrete segment, the second contact terminal making electrical contact with the second discrete segment while providing an electrical connection thereto externally of the housing.




In accordance with another aspect of the present invention, there is provided an electrical connector which comprises a dielectric housing, a plurality of insulated conductors positioned in the housing, a first plurality of contact terminal means positioned in the housing for piercing the insulation of the plurality of insulated conductors in order to make electrical contact therewith, and a second plurality of contact terminal means positioned in the housing for not piercing the insulation of any of the plurality of insulated conductors but for permitting an electrical connection to be made thereto externally of the housing.




In accordance with more specific aspects of the present invention, the contact terminal means, each comprised of substantially planar, electrically conductive contact terminals, have tangs at the lower end thereof for enabling insulated conductors to be pierced, and a spring-contact mateable surface at the other end thereof for enabling contact portions of a mating connector to be coupled thereto. The first plurality of contact terminal means are aligned in a first row, and the second plurality of contact terminal means are aligned in a second row, the first and second rows being substantially parallel to each other. One of the first plurality of contact terminal means is in substantially the same plane with one of the second plurality of contact terminal means.




In accordance with yet another aspect of the present invention, the contact terminals of the first and second Plurality of contact terminal means are positioned in aligned pairs consisting of one contact terminal from the first plurality and one contact terminal from the second plurality, each of the aligned pairs of contact terminals being positioned in substantially the same plane.




In accordance with yet another aspect of this invention, means are provided in the housing for electrically connecting the first and second plurality of contact terminal means, such means comprising substrate means positioned in the housing and having electrically conductive path means positioned thereon. The path means is more particularly adapted to be pierced by the first and second plurality of contact terminal means. More particularly, the path means comprises first and second sets of electrically conductive paths, the first set of paths adapted to be pierced by the first plurality of contact terminal means, the second set of paths adapted to be pierced by the second plurality of contact terminal means.




The substrate means may further include a plurality of first electrical components positioned thereon and coupled to the first and second sets of electrically conductive paths. Further, there may be provided a second electrical component coupled between one of the paths of the first set and one of the paths of the second set. The first and second components may be connected in series.




In accordance with yet another aspect of the present invention, there is provided an electrical connector which comprises a dielectric housing, electrical conductor means positioned in the housing, substrate means positioned in the housing having electrically conductive path means and electrical component means positioned thereon, first means for electrically coupling the electrical conductor means and the path means, and second means, distinct and separate from the first means, for electrically coupling the path means to an external contact of a mating connector. More particularly, the electrical conductor means provides a first signal which is electrically coupled by the first means through the path means and the component means, the component means including modifying means from the first signal to produce a second signal which is electrically coupled by the second means to the external contact of a mating connector.




In accordance with more specific aspects of this invention, the path means includes first and second electrically conductive paths, the electrical component being connected in series between the first and second electrically conductive paths. Further, the electrical conductor means preferably comprises an insulated conductor, while the first means comprises a first contact terminal having tangs for piercing the insulation of the insulated conductor and the first electrically conductive path. Furthermore, the second means comprises a second contact terminal having tangs for piercing the second electrically conductive path on the substrate means. The second contact terminal does not pierce the insulation of the insulated conductor.




In accordance with yet another aspect of the present invention, there is provided an electrical connector which comprises a dielectric housing, an insulate conductor positioned in the housing, substrate means positioned in the housing having first and second discrete electrically conductive paths positioned thereon, electrical components connected between the first and second paths, first electrically conductive terminal means in the housing for piercing the insulated conductor and the first path, and second electrically conductive contact terminal means positioned in the housing for piercing the second path and for permitting an electrical connection to be made thereto externally of the housing. The first and second electrically conductive contact terminal means preferably comprise first and second pluralities of substantially planar contact terminals, each of the contact terminals having tangs at the lower ends thereof capable of piercing the insulation of the conductor. The first and second pluralities of contact terminals are preferably positioned in two adjacent, substantially parallel rows, respectively.











BRIEF DESCRIPTION OF THE DRAWINGS




The foregoing and other objects, aspects and features of the present invention will be more fully appreciated as the same becomes better understood when considered in connection with the following detailed description of the present invention viewed in conjunction with the accompanying drawings, in which:





FIG. 1

is a top, perspective view of a preferred embodiment of a modular plug of the present invention;





FIG. 2

is a rear view in elevation of the preferred embodiment of

FIG. 1

;





FIG. 3

is a cross-sectional view taken along line


3





3


of

FIG. 2

;





FIG. 4

is a top, plan view of the preferred embodiment of the modular plug of the present invention;





FIG. 5

is a top view similar to

FIG. 4

but showing the presence of contact terminals and multi-conductor cable;





FIG. 6

is a front view in elevation of the preferred embodiment illustrated in

FIG. 5

;





FIG. 7

is a longitudinal sectional view of the embodiment illustrated in

FIGS. 5 and 6

showing a multi-conductor cable terminated in the preferred embodiment of the present invention;





FIG. 8

is a sectional view similar to

FIG. 3

but illustrating the presence of a multi-conductor cable in the preferred embodiment of the present invention;





FIG. 9

is a longitudinal sectional view similar to

FIG. 7

but illustrating a second embodiment of the present invention; and





FIG. 10

is a sectional view similar to

FIG. 8

but illustrating the second preferred embodiment of the present invention.











DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT




Referring now to the drawings, wherein like reference numerals indicate identical or corresponding parts throughout the several views, and more particularly to

FIGS. 1-4

thereof, there is illustrated a preferred embodiment of the present invention which includes a modular connector or plug indicated generally by reference numeral


10


.




Plug


10


comprises a unipartite housing


12


which is specifically adapted to terminate a multi-conductor cable (not shown in FIGS.


1


-


4


). Modular plug


10


in this preferred embodiment generally includes features which are generic to a standard modular plug of the type commonly used in both telephone equipment and other cable interconnect applications. A standard modular telephone plug having similar features is set forth, for example, in U.S. Pat. Nos. 3,954,320 and 3,998,514, both of which are expressly incorporated herein by reference. Another version of a standard, miniature modular plug is set forth in my earlier U.S. Pat. No. 4,412,715. However, as will be appreciated hereinafter, the modular plug


10


of the present invention contains important structural and functional modifications when compared with the referenced prior art modular plugs.




Housing


12


of plug


10


includes a free end


14


which is adapted to be inserted into a mating modular jack such as the device described in U.S. Pat. No. 3,850,497, which is expressly incorporated herein by reference. Such a jack typically includes a plurality of side-by-side spring contact members which are placed in a cavity adapted to receive free end


14


of plug


10


for making electrical contact with certain of the plug's contact terminals, as will be described in greater detail below.




Housing


12


also includes a cord or cable input end


16


as well as a terminal receiving side


18


. The cable input end


16


includes a cord receiving cavity


20


into which a multi-conductor cable may be placed.




As shown in

FIGS. 1-3

, cord receiving cavity


20


includes a lower, cable-receiving trough


22


which comprises a semi-depression in the lower wall of cavity


20


against which the outer jacket of the cable rests.




As may be seen in

FIG. 3

, cord-receiving cavity


20


includes a relatively wide, rear cable-receiving portion


24


, a middle conductor-receiving portion


26


located forwardly of portion


24


, and a terminal-receiving portion


28


located at the forwardmost portion of housing


12


near the free end


14


thereof. Positioned between conductor-receiving portion


26


and terminal-receiving portion


28


is a component-receiving portion


30


.




Portions


26


,


28


and


30


together define a substrate-receiving portion indicated generally by reference numeral


62


, which is provided for a purpose that will be described in greater detail hereinafter.




Referring now to

FIGS. 1 and 4

, in the top of housing


12


, adjacent the cord-receiving cavity


20


, is positioned a jacket anchoring member


32


which conventionally is connected to the housing by a hinge and includes a snap-lock ledge that forces member


32


against the outer jacket of the cable to provide strain relief, all of which is quite conventional.




Formed in the middle portion of housing


12


on the terminal-receiving side


18


is a first set of terminal-receiving slots


34


which are defined by a first set of terminal partitions


36


. Slots


34


are each sized so as to receive therein a standard, planar contact terminal that will be described below.




Positioned adjacent the first set of slots


34


is a transverse partition member


38


. On the other side of partition member


38


are positioned a second set of terminal-receiving slots


40


which are, in turn, defined by a second set of terminal partitions


42


arranged side-by-side in a manner similar to terminal partitions


36


. Slots


40


likewise are each sized so as to receive a standard contact terminal, as will be described below. Further, the first and second sets of terminal receiving slots


34


and


40


are positioned on terminal receiving side


18


of housing


12


so as to be in substantial alignment with each other, as best seen in FIG.


4


.




Referring back to

FIG. 2

, housing


12


also includes a standard locking tab or latching arm


44


which is pivotally mounted to the bottom wall of housing


12


. Alternatively, it may be mounted to either side wall. As is conventional, latching arm


44


includes a pair of spaced shoulders


46


which are adapted to be secured by similarly spaced shoulder retaining members in the mating modular jack (not shown).




Referring now to

FIGS. 5 and 6

, they correspond respectively to

FIGS. 4 and 2

, except that

FIGS. 5 and 6

illustrate the plug


10


of the present invention with a multi-conductor cable


50


installed therein. Multi-conductor cable


50


generally includes an outer jacket that surrounds a plurality of individually insulated conductors. Referring to

FIG. 5

, there are illustrated a first set of contact terminals


48


positioned in the first set of side-by-side terminal-receiving slots


34


. Similarly, a second set of contact terminals


52


are shown positioned in the second set of side-by-side terminal-receiving slots


40


.

FIG. 6

illustrates the free end


14


of plug


10


as well as the second set of contact terminals


52


located in slots


40


which are defined by the second set of terminal partitions


42


.





FIG. 7

is a longitudinal sectional view of the structure illustrated in

FIG. 5

wherein it may be appreciated that multi-conductor cable


50


includes a plurality of insulated conductors


54


that are terminated generally in the conductor-receiving portion


26


of the connector. Also illustrated in

FIG. 7

is the pivotal mount


45


of the rearwardly extending latching arm


44


.





FIG. 7

also illustrates the general structure of a preferred embodiment of the first and second set of contact terminals


48


and


52


. Each of the contact terminals, such as contact terminal


52


, includes conductor-piercing tangs


56


at the lower end thereof and a spring-contact mateable surface


58


at the other end thereof which is adapted to come into contact with the similarly-spaced spring contact portion of the mating modular jack, as described above. Contact terminals


48


and


52


are held in place respectively within slots


34


and


40


by a press or interference fit within the reduced portions


55


and


65


of slots


34


and


40


, respectively.




Contact terminal


48


may be substantially identical in form to contact terminal


52


. That is, contact terminal


48


preferably includes a pair of conductor-piercing tangs


64


at the lower end thereof and a spring-contact mateable surface


66


at the upper end thereof. However, surfaces


66


of contact terminals


48


are not intended in this embodiment to mate with spring contact portions of a mating jack, in contrast to the surfaces


58


of contact terminals


52


. More particularly, contact terminals


48


are provided inter alia to terminate the insulated conductors


54


of cable


50


, in a manner which will be described in greater detail hereinafter.




In accordance with the present invention, a thin-flexible substrate indicated generally by reference numeral


60


is positioned within substrate-receiving portion


62


of housing


12


. Substrate


60


is preferably positioned below conductors


54


which overlie approximately ⅓ to ½ of the overall length of substrate


60


, as seen clearly in FIG.


8


. Substrate


60


in this embodiment is generally rectangular and formed of a thin (e.g., 0.0005 inch-0.002 inch) plastic, such as a polyester film, and is sized so as to be interference or press fit along the edges thereof with the side walls that form substrate-receiving portion


62


. The thickness of substrate


60


will in part be selected according to the size of portion


62


and the diameter of insulated conductors


54


. Substrate


60


is preferably flexible so as to be easily manipulated and well-fit within substrate receiving portion


62


.




Referring now to

FIG. 8

, it is a view similar to

FIG. 3

but shows the substrate


60


of the present invention together with a multi-conductor cable


50


both in position within housing


12


. Formed on the upper surface of substrate


60


(or, alternatively, on the bottom surface, or on both surfaces thereof) by any conventional technique is a first set of metal traces or conductive paths


68


. Details concerning the dimensions of the conductive paths, the thicknesses thereof, and the manner of formation of same are fully described in my earlier U.S. Pat. No. 4,412,715, the specification of which is expressly incorporated herein by reference.




In this improvement over my earlier '715 patent, there are provided two distinctly separate sets of conductive paths: the first is designated by reference numeral


68


which, as noted above, are formed at one end of substrate


60


in alignment with the position of insulated conductors


54


which overlie same.




Positioned at the other end of substrate


60


, and in alignment with the first set of conductive paths


68


, is a second set of metal traces or conductive paths


72


. Again, traces


72


may be substantially identical in size to the aligned first set of traces


68


. The second set of traces


72


are also positioned so that each trace underlies a respective one of the second set of terminal-receiving slots


40


, and hence contact terminals


52


, as will be described in more detail below.




Located between the first and second set of traces


68


and


72


are a plurality of electrical or electronic components


70


which are selected and designed to act in a specific manner upon the electrical signals received from insulated conductors


54


.




Each of the individual components


70


are electrically connected to adjacent ends of traces


68


and


72


to form an electrical series circuit. Of course, the components


70


may be the same or different components, and may or may not be provided in each of the individual positions on the substrate, as may be desired for a particular application. Certain electrical components


70


may comprise, for example, simple resistors, while other components may comprise active devices, such as transistors or integrated circuits. Any suitable electrical or electronic component may be selected that acts in the desired predictable, specific manner upon an electrical signal that is desired to be modified.




It may be appreciated from

FIGS. 7 and 8

that the first set of contact terminals


48


terminate each of the individual insulated conductors


54


as well as the underlying first set of conductive paths


68


on substrate


60


. Thus, the electrical signals appearing on insulated conductors


54


are electrically coupled, via contact terminals


48


, to the first set of metal traces


68


.




It also may be appreciated from

FIGS. 7 and 8

that the second set of contact terminals


52


serve the function of piercing and thereby terminating the second set of conductive paths


72


such that any signal appearing on paths


72


is transmitted through contact terminals


52


to the spring-contact terminals of the mating modular jack (not shown). Thus, contact terminals


52


are used as terminating devices for substrate


60


, but are not designed to terminate the insulated conductors


54


.




In a similar vein, contact terminals


48


are used to terminate the insulated conductors


54


, but are not used to couple the signals therefrom to any external mating modular jack. Rather, contact terminals


48


couple the signal from conductors


54


to the substrate


60


.




Positioned between traces


68


and


72


are electrical components


70


which respectively act on the input signals from traces


68


so as to modify them in a predetermined manner. The modified signals are then fed to the output traces


72


so as to be coupled to an output device via contact terminals


52


, as described above. In this manner, the incoming signals on cable


50


, appearing on individual insulated conductors


54


, may be modified in a precise, predetermined manner by preselected electrical components


70


before being output to a mating modular jack.




Referring now to

FIGS. 9 and 10

, there is illustrated a second embodiment of the present invention. This second embodiment is quite similar to the first embodiment shown in

FIGS. 7 and 8

. However, in addition to the first set of electrical components


70


, there is provided on substrate


60


a second set of electrical components


80


which are preferably series connected to the first set of components


70


by connecting traces or conductive paths


75


.




In this embodiment, the incoming electrical signals along insulated conductors


54


may be modified both by the first set of electrical components


70


and the second set of electrical components


80


before being output to the mating modular jack (not shown). This provides an additional degree of design capability to the present invention.




Obviously, numerous modifications and variations of the present invention are possible in light of the above teachings. For example, the electrical components


70


and/or


80


may be vastly different, one from the other, depending on the desired application. In addition, the present invention may be used in other electrical connectors, such as sub-miniature D connectors and circular pin connectors. In view thereof, it should be understood that within the scope of the appended claims, the invention may be practiced otherwise than as specifically described herein.



Claims
  • 1. An electrical connector, which comprises:a dielectric housing; a plurality of insulated conductors positioned in said housing; a first plurality of contact terminals, each said contact terminal positioned in said housing for piercing the insulation of an individual one of said plurality of insulated conductors in order to make electrical contact therewith; and a second plurality of contact terminals positioned in said housing for not piercing the insulation of and not electrically engaging any of said plurality of insulated conductors in said housing, but for permitting an electrical connection to be made thereto externally of said housing.
  • 2. The electrical connector as set forth in claim 1, wherein said first and second plurality of contact terminals each comprise a substantially planar, electrically conductive contact terminal having tangs at the lower end thereof for enabling insulated conductors to be pierced, and a spring-contact mateable surface at the other end thereof for enabling contact portions of a mating connector to be coupled thereto.
  • 3. The electrical connector as set forth in claim 2, wherein said first plurality of contact terminals are aligned in a first row, and said second plurality of contact terminals are aligned in a second row, said first and second rows being substantially parallel to each other.
  • 4. The electrical connector as set forth in claim 2, wherein one of said first plurality of contact terminals is in substantially the same plane with one of said second plurality of contact terminals.
  • 5. The electrical connector as set forth in claim 2, wherein each of said contact terminals of said first plurality are substantially parallel to each other, and each of said contact terminals of said second plurality are substantially parallel to each other.
  • 6. The electrical connector as set forth in claim 5, wherein said contact terminals of said first and second plurality of contact terminals are positioned in aligned pairs consisting of one contact terminal from said first plurality and one contact terminal from said second plurality, each of said aligned pairs of contact terminals positioned in substantially the same plane.
  • 7. The electrical connector as set forth in claim 6, further comprising a conductor in said housing for electrically connecting said first and second plurality of contact terminal.
  • 8. The electrical connector as set forth in claim 7, wherein said conductor further includes a substrate positioned in said housing on which an electrically conductive path is positioned.
  • 9. The electrical connector as set forth in claim 8, wherein said conductive path is adapted to be pierced by said first and second plurality of contact terminals.
  • 10. The electrical connector as set forth in claim 9, wherein said conductive path comprises first and second sets of electrically conductive paths, said first set of paths adapted to be pierced by said first plurality of contact terminals, said second set of paths adapted to be pierced by said second plurality of contact terminals .
  • 11. The electrical connector as set forth in claim 10, wherein said substrate further comprises a plurality of first electrical components positioned thereon and coupled to said first and second sets of electrically conductive paths.
  • 12. The electrical connector as set forth in claim 11, wherein one of said plurality of first electrical components is coupled between one of said paths of said first set and one of said paths of said second set.
  • 13. The electrical connector as set forth in claim 12, further comprising a second electrical component coupled between said one of said paths of said first set and said one of said paths of said second set.
  • 14. The electrical connector as set forth in claim 11, wherein said plurality of first electrical components are connected respectively in series between said first set of electrically conductive paths and said second set of electrically conductive paths.
  • 15. The electrical connector as set forth in claim 14, further comprising a plurality of second electrical components connected respectively in series with said plurality of first electrical components.
  • 16. An electrical connector, which comprises:a dielectric housing; an insulated conductor positioned in said housing; a substrate positioned in said housing and having first and second discrete electrically conductive paths positioned thereon and an electrical component connected between said first and second paths; a first electrically conductive contact terminal positioned in said housing for piercing said insulated conductor and said first path; and a second electrically conductive contact terminal positioned in said housing for piercing said second path without piercing said insulated conductor and for permitting an electrical connection to be made thereto externally of said housing.
  • 17. The electrical connector as set forth in claim 16, wherein said first and second electrically conductive contact terminals comprise first and second pluralities of substantially planar contact terminals, each of said contact terminals having tangs at the lower ends thereof capable of piercing the insulation of said conductor.
  • 18. The electrical connector as set forth in claim 17, wherein said first and second pluralities of contact terminals are positioned in two adjacent, substantially parallel rows, respectively.
US Referenced Citations (34)
Number Name Date Kind
4054350 Hardesty Oct 1977 A
4288142 Anderton Sep 1981 A
4412715 Bogese, II Nov 1983 A
4428636 Kam et al. Jan 1984 A
4516825 Brennen et al. May 1985 A
4533195 Knickerbocker Aug 1985 A
4679879 Triner et al. Jul 1987 A
4767355 Phillipson et al. Aug 1988 A
4950169 Martin et al. Aug 1990 A
4950176 Cocco et al. Aug 1990 A
4975078 Stroede et al. Dec 1990 A
4978316 Yahata Dec 1990 A
5147215 Pritulsky et al. Sep 1992 A
5179779 Iura et al. Jan 1993 A
5186647 Denkmann et al. Feb 1993 A
5186649 Fortner et al. Feb 1993 A
5194014 McClune et al. Mar 1993 A
5284447 Kristiansen Feb 1994 A
5305380 Hileman et al. Apr 1994 A
5310363 Brownell et al. May 1994 A
5385484 Bartle et al. Jan 1995 A
5415567 Fusselman et al. May 1995 A
5421741 David et al. Jun 1995 A
5431584 Ferry Jul 1995 A
5432484 Klas Jul 1995 A
5538438 Orlando Jul 1996 A
5556295 McFadden et al. Sep 1996 A
5571035 Ferrill Nov 1996 A
5580270 Pantland et al. Dec 1996 A
5593314 Lincoln Jan 1997 A
5628647 Rohrbaugh et al. May 1997 A
5727962 Caveney et al. Mar 1998 A
5971812 Martin Oct 1999 A
6007368 Lorenz et al. Dec 1999 A
Foreign Referenced Citations (3)
Number Date Country
2345149 Dec 1972 DE
3918517 Jun 1990 DE
2249222 Apr 1992 GB