Hermaphroditic contact

Information

  • Patent Grant
  • 6193537
  • Patent Number
    6,193,537
  • Date Filed
    Monday, May 24, 1999
    25 years ago
  • Date Issued
    Tuesday, February 27, 2001
    23 years ago
Abstract
A connector having a hermaphroditic contact is disclosed. Such hermaphroditic contact extends longitudinally and is formed as a unitary body from a conductive material. The contact has a base residing in a plane and extending longitudinally and traversely in the plane, a blade arm extending longitudinally from the base and generally in the plane of the base, and a spring arm extending longitudinally from the base alongside the blade arm. The spring arm is springingly displaceable toward at least a first side of the plane of the base. To electrically couple first and second generally identical ones of the contact, the bases of the first and second contacts are aligned to be co-planar, and the blade arm of the each contact is aligned to face toward the spring arm of the other contact. The first and second contacts are then moved together such that the blade arm of each contact encounters the spring arm of the other contact. Thereafter, the first and second contacts are further moved together such that the blade arm of each contact displaces the spring arm of the other contact toward the first side of the plane of the base of the other contact.
Description




FIELD OF THE INVENTION




The present invention relates to an electrical contact for mating with a substantially identical copy thereof. In particular, the present invention is for such an electrical contact having a blade arm and a spring arm.




BACKGROUND OF THE INVENTION




Relatively small yet relatively dense electrical connectors are employed in many applications. In one type of application, a first connector is mounted to a first substrate and a second, mating connector is mounted to a second substrate so that the first substrate may be electrically coupled to the second substrate by mating contacts on the first and second connectors. Typically, each of the first and second connectors have a plurality of electrical contacts mounted therein, and each contact in the first connector is for mating with a specific corresponding contact in the second connector. Such contacts in each of the first and second connectors may be arranged into rows and columns, staggered rows or any other desirable arrangement.




Generally speaking, each connector utilizes different contacts than the other connector. For example, the first connector could use pin contacts and the second connector could use receptacle contacts. In another type, the first connector could use blade contacts and the second connector could use spring arm, or beam contacts. Of course, other types of mate-able electrical connector pairs are extant.




Using different contacts for each connector in the pair has several disadvantages. First, each such different type of contact must be individually designed and produced. Second, each contact must be kept in inventory. Moreover, care must taken to ensure that the proper contact is mounted in the proper connector. Accordingly, a need exists for a connector having contacts where each contact can mate to a generally identical contact in a mating connector. With such hermaphroditic contacts, then, design and production costs are significantly reduced.




SUMMARY OF THE INVENTION




The present invention satisfies the aforementioned need by providing a hermaphroditic contact and a connector having such a hermaphroditic contact. Such hermaphroditic contact extends longitudinally and is formed as a generally unitary body from a conductive material. The contact has an intermediate portion generally residing in a plane and extending longitudinally and traversely in the plane, a blade arm extending longitudinally from the intermediate portion and generally in the plane of the intermediate portion, and a spring arm extending longitudinally from the intermediate portion alongside the blade arm. The spring arm is displaceable toward at least a first side of the plane of the intermediate portion during mating with the other contact.




To electrically couple first and second generally identical ones of the contact, the intermediate portions of the first and second contacts are aligned to be generally co-planar, and the blade arm of the each contact is aligned to face generally toward the spring arm of the other contact. The first and second contacts are then moved together such that the blade arm of each contact encounters the spring arm of the other contact. Thereafter, the first and second contacts are further moved together such that the blade arm of each contact displaces the spring arm of the other contact toward the first side of the plane of the intermediate portion of the other contact.











BRIEF DESCRIPTION OF THE DRAWINGS




The foregoing summary as well as the following detailed description of the embodiments of the present invention, will be better understood when read in conjunction with the appended drawings. For the purpose of the illustrating the invention, there are shown in the drawings embodiments which are presently preferred. As should be understood, however, the invention is not limited to the precise arrangements and instrumentalities shown. In the drawings:





FIG. 1

is a perspective view of a hermaphroditic contact in accordance with one embodiment of the present invention; and





FIGS. 2A and 2B

are perspective views of first and second ones of the hermaphroditic contact of

FIG. 1

mounted in first and second connectors, respectively, where the connectors/contacts are mated by being aligned with respect to each other (FIG.


2


A), and by being moved toward and encountering each other (FIG.


2


B).











DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS




Certain terminology may be used in the following description for convenience only and is not considered to be limiting. The words “left”, “right”, “upper”, and “lower” designate directions in the drawings to which reference is made. The words “inwardly” and “outwardly” are further directions toward and away from, respectively, the geometric center of the referenced object. The terminology includes the words above specifically mentioned, derivatives thereof, and words of similar import.




Referring to the drawings in detail, wherein like numerals are used to indicate like elements throughout, there is shown in

FIG. 1

a hermaphroditic electrical contact


10


in accordance with one embodiment of the present invention. As seen, the contact


10


extends generally longitudinally and is formed as a generally unitary body. The contact


10


includes an intermediate portion


12


that generally resides in a plane. Contact


10


has a mating portion extending from intermediate portion


12


to engage a mating portion of a mating contact


10


(shown in FIGS.


2


A and


2


B). The mating portion includes a blade arm


14


that extends longitudinally and generally in the plane of the intermediate portion


12


, and a spring arm


16


that extends longitudinally from the intermediate portion


12


alongside the blade arm


14


. The distal ends of the blade arm


14


and spring arm


16


are adjacent one another although spring arm


16


can extend further from intermediate portion


12


. Preferably, the spring arm


16


is springingly displaceable toward at least a first side of the plane of the intermediate portion


12


as shown by the arrow S in

FIG. 1

when mating with another contact


10


.




Preferably, the contact


10


is constructed from a conductive material, such as beryllium-copper or phosphor-bronze with suitable plating in the mating area. Preferably, the method of constructing the contact


10


is by stamping and forming a sheet of material. The stamping operation may cut the contact from the sheet while the forming operation provides the bends. Alternatively, the contact


10


may be formed by molding or any other suitable process. At any rate, it will be recognized that other materials and other methods of construction may be employed without departing from the spirit and scope of the present invention.




Referring now to

FIGS. 2A and 2B

, it is seen that first and second generally identical contacts


10




a,




10




b


may be mounted in first and second paired mating connector housings


18




a


,


18




b


(two pairs of such first and second contacts


10




a


and


10




b


are shown). Preferably, each connector


18




a


,


18




b


is molded from a suitable dielectric material such as a thermoplastic like a liquid crystal polymer (LCP) into a final form which includes defined apertures for each respective contact


10




a,




10




b.


However other methods of formation of the connectors


18




a


,


18




b


may be employed without departing from the spirit and scope of the present invention.




As seen, each contact


10


,


10




a,




10




b


includes a pair of shoulders


20


where each shoulder


20


is associated with one of the blade arm and spring arm


14


,


16


. Preferably, each contact


10




a,




10




b


is inserted within an aperture


21


in a respective connector housing


18




a


,


18




b


through a floor


22


thereof (best seen in

FIG. 2B

) such that each shoulder


20


of each contact


10




a,




10




b


is generally flush with the floor


22


of the respective connector


18




a


,


18




b


. As should be understood, the floors of the connectors


18




a


,


18




b


are the respective generally planar surfaces that face each other when the connectors


18




a


,


18




b


are mated to one another. Preferably, each aperture


21


has a deformable rib (not shown) at a central location. The rib retains contacts


10




a,




10




b


within apertures


21


by an interference fit. Alternatively, apertures


21


could have generally planar side walls (i.e. no ribs) spaced close together such that a received contact


10




a,




10




b


maintains a snug interference fit therein.




The insertion of each contact


10




a,




10




b


into the aperture


21


of the respective connector


18




a


,


18




b


may be performed by any of several known processes without departing from the spirit and scope of the present invention. For example, each contact


10




a,




10




b


may be machine inserted within an aperture


21


in an already-formed connector


18




a


,


18




b


by mechanical means. Alternatively, each contact


10




a,




10




b


may be over-molded in situ during formation of the respective connector


18




a


,


18




b.






Referring again to

FIG. 1

, it is seen that the intermediate portion


12


of the contact


10


includes a mounting portion


23


generally opposite the blade arm and spring arm


14


,


16


. As seen in

FIGS. 2A and 2B

, mounting portion


23


could receive a fusible element such as a solder ball


28


to surface-mount the connector


18




a


,


18




b


to a substrate using, for example, ball grid array (BGA) technology. Intl. Pub. No. WO 98/15991, hereby incorporated by reference, describes methods for securing a fusible element to a contact and for securing a connector using fusible elements to a circuit substrate. As seen, the mounting portion


23


includes a pair of laterally arranged posts


24


extending longitudinally from the intermediate portion


12


. A re-flow step fuses the solder ball


28


to the mounting portion


23


. Preferably, posts


24


reside within the fused solder ball


28


. In general, any structure for forming the solder ball mounting portion


23


, such as, for example, a bent tab, may be employed without departing from the spirit and scope of the present invention. In addition, a contact


10


could use a different type of termination (e.g. solder tail, press-fit, pin-in-paste).




The mounting portion


23


of contact


10


also includes a centrally located region between the posts


24


, where the region includes a shaped edge


25


that may be formed by a coining process. Such coining process smooths the edge


25


and provides a tapered or rounded edge


25


. During insertion of contact


10


into aperture


21


in the housing


18


, the rounded edge


25


prevents skiving of the retaining rib within the aperture


21


. The absence of skived material obviates the need for a removing process before the placing and re-flowing of the solder ball


28


. As best seen in

FIGS. 2A and 2B

, with each contact


10




a,




10




b


inserted in each connector


18




a


,


18




b


, the solder ball mounting portion


23


of such contact


10


preferably resides, at least partially, within a well


26


on the surface of the respective connector


18




a


,


18




b


opposite the floor


22


thereof. As positioned, each solder ball mounting portion


23


may then receive and hold a solder ball


28


and/or solder paste also at least partially residing in well


26


. Any method of attaching a solder ball


28


to each solder ball mounting portion


23


may be employed without departing from the spirit and scope of the present invention. Furthermore, mounting portion


23


could extend past well


26


.




In general, any method of attaching a solder ball


28


to each solder ball mounting portion


23


may be employed without departing from the spirit and scope of the present invention. Of course, if a solder ball


28


is not to be employed to couple each contact


10


to a corresponding electrical pad on a substrate, the posts


24


and rounded edge


25


may not be necessary, and may be substituted with other suitable terminations without departing from the spirit and scope of the present invention.




Referring still to

FIGS. 2A and 2B

, it is seen that the first and second connectors


18




a


,


18




b


are coupled to one another and that respective first and second generally identical ones of the contacts


10




a,




10




b


are electrically coupled to one another by performing the following steps. First, the intermediate portions


12


of each corresponding pair of first and second contacts


10




a,




10




b


are aligned to be generally co-planar. Preferably, each contact


10




a,




10




b


is positioned in a respective connector


18




a


,


18




b


such that alignment of, for example, the peripheral walls of the connectors


18




a


,


18




b


automatically aligns the intermediate portions


12


of the respective first and second contacts


10




a,




10




b


to be coplanar.




As seen from

FIGS. 2A and 2B

, the pair of mating connectors


18




a


,


18




b


preferably include various keying features such as shoulders and extensions. As should be understood, such keying features act to precisely position the connectors


18




a


,


18




b


and by extension each corresponding pair of contacts


10




a,




10




b


with respect to each other when such connectors


18




a


,


18




b


are being mated to each other. Accordingly, such contacts


1




a,




10




b


are not inadvertently crumpled or otherwise damaged due to a mis-alignment during mating.




Thereafter, the blade arm


14


of each contact


10




a,




10




b


is aligned to face generally toward the spring arm


16


of the other contact


10




a,




10




b.


Of course, in the context of the connectors


18




a


,


18




b


this is accomplished in connection with the previous aligning step merely by ensuring that the floors


22


of the connector


18




a


,


18




b


face toward each other.




Once properly aligned, as is seen in

FIG. 2A

, the connectors


18




a


,


18




b


, and by extension the first and second contacts


10




a,




10




b,


are moved together, such that the blade arm


14


of each contact


10




a,




10




b


encounters the spring arm


16


of the opposite contact


10




a,




10




b.


As should be understood, the aforementioned keying features incorporated within the connectors


18




a


,


18




b


and the respective contacts


10




a


,


10




b


ensure that such encountering occurs in proper alignment.




Thereafter, the connectors


10




a,




10




b,


and by extension the first and second contacts


10




a,




10




b,


are further moved together such that the blade arm


14


of each contact


10




a,




10




b


displaces the spring arm


16


of the opposite contact


10




a,




10




b


toward the first side of the intermediate portion


12


of the opposite contact


10




a,




10




b.


Again, such first side of such intermediate portion


12


is shown by the direction of the arrow S in FIG.


1


.




Referring again to

FIG. 1

, it is seen that the spring arm


16


of each contact


10


preferably includes first, second, and third portions


30




a


,


30




b


,


30




c


as delineated by the respective brackets. As seen, the first portion


30




a


is relatively close to the intermediate portion


12


and serves to extend arm


16


away from the plane of such intermediate portion


12


. The second portion


30




b


is further away from the intermediate portion


12


than the first portion


30




a


and has a mating portion that approaches and generally resides in the plane of the intermediate portion


12


. The third portion


30




c


is further away from the intermediate portion


12


than the second portion


30




b


and serves to extend the distal tip of arm


16


away from the plane of intermediate portion


12


as represented by the direction of the arrow S in FIG.


1


. As seen, the third portion


30




c


generally curves away from the second portion


30




b


and toward such first side.




As should be understood, with the spring arm


16


having the first, second, and third portions


30




a


,


30




b


,


30




c


as described and shown, when the first and second contacts


10




a,




10




b


are moved together, the blade arm


14


of each contact


10




a,




10




b


may first encounter the third portion


30




c


of the spring arm


16


of the opposite contact


10




a,




10




b.


Third portion


30




c


acts as a lead-in surface to accommodate slight misalignments of the contacts


10




a,




10




b.


Likewise, when such first and second contacts


10




a,




10




b


are further moved together such that displacement of each spring arm


16


occurs, the blade arm


14


of each contact


10




a,




10




b


encounters the second portion


30




b


of the spring arm


16


of the opposite contact


10




a,




10




b.






Preferably, and as seen in

FIG. 1

, the first portion


30




a


of the spring arm


16


generally resides on the first side of the plane of the intermediate portion


12


, as referenced by the direction of the arrow S. In particular, it is preferable that the first portion


30




a


of the spring arm


16


of the contact


10


have a proximal end


30




ap


that curves toward the intermediate portion


12


of such contact


10


and a distal end


30




ad


that curves toward the second portion


30




b


. Accordingly, when viewed from one lateral side thereof, the spring arm


16


generally exhibits an S-shape. Of course, other particular shapes may be employed without departing from the spirit and scope of the present invention.




As shown, the first portion


30




a


having the aforementioned ends


30




ap,




30




ad


defines a blade arm acceptance region


32


that is generally adjacent such first portion


30




a


and that is generally in the plane of the intermediate portion


12


. As should now be understood, after the first and second contacts


10




a,




10




b


have been further moved together, such first and second contacts


10




a,




10




b


may be still further moved together such that the blade arm


14


of each contact


10




a,




10




b


enters the blade arm acceptance region


32


of the opposite contact


10




a,




10




b


while continuing to displace the spring arm


16


of such opposite contact


10




a,




10




b


in the direction of the arrow S. Of course, in such position, the blade arm


14


of each contact


10




a,




10




b


also continues to encounter the second portion


30




b


of the spring arm


16


of the opposite contact


10




a,




10




b.






Preferably, and as best seen in

FIGS. 2A and 2B

, the floor


22


of each connector


18




a


,


18




b


defines a well


34


as part of the aperture


21


. The well


34


can include a relatively larger opening adjacent the blade arm


14


of each connector


10




a,




10




b


and a relatively smaller opening adjacent the spring arm


16


and on the opposite side of aperture


21


from the larger opening. Preferably, each contact


10




a,




10




b


is inserted within an aperture


21


and each aperture


21


is formed such that both the blade arm


14


and the spring arm


16


of each contact


10




a,




10




b


extend longitudinally and generally perpendicularly with respect to such floor


22


of the respective connector


10




a,




10




b.


Accordingly, when each contact


10




a,




10




b


in one connector


18




a


,


18




b


is electrically coupled to a generally identical corresponding contact


10




a,




10




b


in an opposite connector


18




a


,


18




b


, the larger opening of the well


34


adjacent the blade arm


14


of each contact


10




a,




10




b


accommodates the spring arm


16


of the opposite contact


10




a,




10




b,


and the smaller opening of the well


34


adjacent the spring arm


16


accommodates the blade arm


14


of the opposite contact


10




a,




10




b.


In particular, the larger opening of such well


34


accommodates at least the second and third portions


30




b


,


30




c


of such spring arm


16


. The larger opening of the well


34


has a size suitable to allow deflection of the arm


16


during mating of the connectors


18




a


,


18




b


. The smaller opening of the well


34


is sized to receive a distal tip of such blade arm


14


without substantial interference.




In the foregoing description, it can be seen that the present invention comprises a new and useful hermaphroditic electrical contact


10


,


10




a,




10




b


for being mounted in a connector


18




a


,


18




b


and for mating to a substantially identical contact


10


,


10




a,




10




b.


It should be appreciated that changes could be made to the embodiments described above without departing from the inventive concepts thereof. It should be understood, therefore, that this invention is not limited to the particular embodiments disclosed, but it is intended to cover modifications within the spirit and scope of the present invention as defined by the appended claims.



Claims
  • 1. A longitudinally extending hermaphroditic contact formed as a generally unitary body from a conductive material and comprising:an intermediate portion generally residing in a plane and extending longitudinally and laterally in the plane; a blade arm extending longitudinally from the intermediate portion and generally in the plane of the intermediate portion; a spring arm extending longitudinally from the intermediate portion alongside the blade arm, the spring arm being springingly displace-able toward at least a first side of the plane of the intermediate portion; and a mounting portion extending from the intermediate portion generally opposite the blade arm and the spring arm and generally in-line therewith the mounting portion being generally co-planar with the intermediate portion.
  • 2. The contact of claim 1 wherein the blade arm and the spring arm are laterally arranged and both extend from the intermediate portion in one general longitudinal direction.
  • 3. The contact of claim 1 wherein the spring arm has:a first portion relatively close to the intermediate portion; a second portion farther away from the intermediate portion than the first portion and generally residing in the plane of the intermediate portion; and a third portion farther away from the intermediate portion than the second portion and generally residing on the first side of the plane of the intermediate portion, the third portion generally extending away from the second portion and toward such first side.
  • 4. The contact of claim 3 wherein the first portion of the spring arm generally resides on the first side of the plane of the intermediate portion, the first portion thereby defining a blade arm acceptance region adjacent thereto and generally in the plane of the intermediate portion.
  • 5. The contact of claim 4 wherein the first portion of the spring arm has a proximal end curving toward the intermediate portion and a distal end curving toward the second portion.
  • 6. The contact of claim 1 mounted to a floor of a connector, the blade arm and the spring arm both extending longitudinally and generally perpendicularly with respect to the floor of the connector, the floor of the connector defining a well adjacent the blade arm on a second side of the plane of the intermediate portion opposite the first side, wherein when the contact is electrically coupled to a generally identical corresponding contact, the well accommodates the spring arm of the corresponding contact.
  • 7. A longitudinally extending hermaphroditic contact formed as a generally unitary body from a conductive material and comprising:an intermediate portion defining a plane; a mounting portion extending from the intermediate portion in a first direction, the mounting portion being generally co-planar with the intermediate portion; and a mating portion extending from the intermediate portion in a second direction generally opposite the first direction, the mating portion having: a blade generally coplanar with the intermediate portion; and a spring arm adjacent the blade and residing at least partially outside the plane of the intermediate portion.
  • 8. The contact of claim 7 wherein the blade and the spring arm are laterally arranged and both extend from the intermediate portion in one general longitudinal direction.
  • 9. The contact of claim 7 wherein the spring arm has:a first portion relatively close to the intermediate portion; a second portion farther away from the intermediate portion than the first portion and generally residing in the plane of the intermediate portion; and a third portion farther away from the intermediate portion than the second portion and generally residing on a first side of the plane of the intermediate portion, the third portion generally extending away from the second portion and toward such first side.
  • 10. The contact of claim 9 wherein the first portion of the spring arm generally resides on the first side of the plane of the intermediate portion, the first portion thereby defining a blade arm acceptance region adjacent thereto and generally in the plane of the intermediate portion.
  • 11. The contact of claim 10 wherein the first portion of the spring arm has a proximal end curving toward the intermediate portion and a distal end curving toward the second portion.
  • 12. The contact of claim 7 mounted to a floor of a connector, the blade and the spring arm both extending longitudinally and generally perpendicularly with respect to the floor of the connector, the floor of the connector defining a well adjacent the blade arm, wherein when the contact is electrically coupled to a generally identical corresponding contact, the well accommodates the spring arm of the corresponding contact.
  • 13. A longitudinally extending hermaphroditic contact formed as a generally unitary body from a conductive material and comprising:an intermediate portion having generally opposing edges and defining a plane; a mounting portion extending from one of the edges of the intermediate portion; and a bifurcated mating portion extending from the other of the edges of the intermediate portion, the mating portion having: a blade extending generally parallel to the plane of the intermediate portion; and a spring arm adjacent the blade and residing at least partially outside the plane of the intermediate portion, the spring arm having an arcuate shape, the mounting portion extending from the edge of the intermediate portion within a lateral boundary defined by the blade arm and the spring arm.
  • 14. The contact of claim 13 wherein the blade and the spring arm are laterally arranged and both extend from the intermediate portion in one general longitudinal direction.
  • 15. The contact of claim 13 wherein the spring arm has:a first portion relatively close to the intermediate portion; a second portion farther away from the intermediate portion than the first portion and generally residing in the plane of the intermediate portion; and a third portion farther away from the intermediate portion than the second portion and generally residing on a first side of the plane of the intermediate portion, the third portion generally extending away from the second portion and toward such first side.
  • 16. The contact of claim 15 wherein the first portion of the spring arm generally resides on the first side of the plane of the intermediate portion, the first portion thereby defining a blade arm acceptance region adjacent thereto and generally in the plane of the intermediate portion.
  • 17. The contact of claim 16 wherein the first portion of the spring arm has a proximal end curving toward the intermediate portion and a distal end curving toward the second portion.
  • 18. The contact of claim 13 mounted to a floor of a connector, the blade and the spring arm both extending longitudinally and generally perpendicularly with respect to the floor of the connector, the floor of the connector defining a well adjacent the blade arm, wherein when the contact is electrically coupled to a generally identical corresponding contact, the well accommodates the spring arm of the corresponding contact.
  • 19. An interconnection system comprising first and second mate-able connectors, each of the first and second connectors having:a housing; and a plurality of contacts mounted in the housing, each contact being a longitudinally extending hermaphroditic contact formed as a generally unitary body from a conductive material and including: an intermediate portion defining a plane; a mounting portion extending from the intermediate portion in a first direction, the mounting portion being generally co-planar with the intermediate portion; and a mating portion extending from the intermediate portion in a second direction generally opposite the first direction, the mating portion having: a blade generally coplanar with the intermediate portion; and a spring arm adjacent the blade and residing at least partially outside the plane of the intermediate portion; each contact in the first connector having a corresponding generally identical contact in the second connector, wherein the blades of each pair of corresponding contacts are generally coplanar during mating of the first and second connectors.
  • 20. The system of claim 19 wherein the blade and the spring arm in each contact are laterally arranged and both extend from the intermediate portion in one general longitudinal direction.
  • 21. The system of claim 19 wherein the spring arm in each contact has:a first portion relatively close to the intermediate portion of the contact; a second portion farther away from the intermediate portion than the first portion and generally residing in the plane of the intermediate portion; and a third portion farther away from the intermediate portion than the second portion and generally residing on a first side of the plane of the intermediate portion, the third portion generally extending away from the second portion and toward such first side.
  • 22. The system of claim 21 wherein the first portion of the spring arm of each contact generally resides on the first side of the plane of the intermediate portion of the contact, the first portion thereby defining a blade arm acceptance region adjacent thereto and generally in the plane of the intermediate portion.
  • 23. The system of claim 22 wherein the first portion of the spring arm of each contact has a proximal end curving toward the intermediate portion of the contact and a distal end curving toward the second portion.
  • 24. The system of claim 19 wherein each contact is mounted to a floor of the respective connector, the blade and the spring arm both extending longitudinally and generally perpendicularly with respect to the floor of the connector, the floor of the connector defining a well adjacent the blade arm, wherein when the contact is electrically coupled to a generally identical corresponding contact, the well accommodates the spring arm of the corresponding contact.
US Referenced Citations (11)
Number Name Date Kind
3115379 McKee Dec 1963
3259869 Batcheller Jul 1966
4820182 Harwath et al. Apr 1989
5035639 Kilpatrick et al. Jul 1991
5098311 Roath et al. Mar 1992
5127839 Korsunsky et al. Jul 1992
5266046 Bogiel Nov 1993
5290181 Bixler Mar 1994
5577928 Duclos Nov 1996
5588859 Maurice Dec 1996
5904581 Pope et al. May 1999
Foreign Referenced Citations (1)
Number Date Country
WO 9815991 Apr 1998 WO