Magnetic coupler and associated method for coupling conductors

A magnetic coupler for magnetically or inductively coupling a pair of conductors. The coupler includes a first magnetic core member having prongs and at least one slot between the prongs for receiving the conductors, and a second magnetic core member. The coupler further includes a base for retaining the first core member and a shuttle for retaining the second core member. The shuttle is slidably mounted within the base such that the shuttle slides across and in contact with the prongs from an open position in which the slot is exposed to a closed position in which the slot is covered by the second core member, and the conductors are thereby contained within the slot. The sliding action of the cores cleans debris off the mating surfaces of the core elements to provide good mating contact between the core members for efficient coupling.

BACKGROUND 
The present invention relates to a coupler which is useful in magnetically 
or inductively coupling a pair of communication loops, power loops, or 
combined power and modulated data loops. 
Electrical communication systems often comprise a number of interrelated 
but physically separated subsystems. Data may be communicated from the 
source terminal to the subsystems, and from the subsystems to the source 
terminal, by means of electrical conductors carrying voltage variations. 
The terminal and the subsystems may each have a wire loop or conductor 
emanating therefrom, and the conductors may be efficiently coupled by 
means of a coupler. The efficiency of the coupler preferably reaches 
levels of over 90%. Voltage variations transmitted via the conductors may 
then communicate data between the source terminal and substations. 
Further, magnetic coupling allows for easy connecting and unconnecting of 
the source terminal and the subsystems so that various subsystems or 
branches may be removed and/or replaced without shutting down the entire 
system. One example of a communication system using magnetic coupling is 
U.S. Pat. No. 4,264,827. 
In order to magnetically couple insulated conductors, the conductors should 
be placed in close proximity to each other. Surrounding the coupled 
conductors with magnetic cores increases induction efficiency. One such 
application of magnetic couplers for use with electronic communication 
devices or systems is disclosed in commonly-owned U.S. Pat. app. Ser. No. 
08/398,297 filed Mar. 3, 1995 in the name of Frederick et al., hereby 
incorporated by reference. That application discloses an article 
information display system using electronically controlled tags. More 
particularly, an apparatus for displaying the price and name of a product 
on electronic display tags adjacent to the respective products is 
disclosed. The system displays information for individual articles, and 
the displays can be updated from a central location. The application 
discloses the use of a "clam-shell" coupler to couple a branch 
distribution loop to a main distribution loop. In this manner, information 
concerning the article for sale may be communicated from the main terminal 
to the substations. 
Couplers are typically movable from an open position, wherein the core 
elements are separate and exposed to the environment, to a closed position 
where the core elements are pressed together and the conductors are 
contained therein. It is known that debris trapped between the magnetic 
core elements may lower the efficiency of the coupler. Dirt, dust, or 
residue from the manufacturing process collected on core elements lowers 
the effectiveness of the coupler. Accordingly, there exists a need for a 
coupler which can clean debris off of the exposed core elements to thereby 
provide intimate contact between the cores. There also exists a need for a 
coupler which can be quickly and easily operated by a worker on-site to 
allow convenient connection of conductors. 
SUMMARY OF THE INVENTION 
In one aspect of the present invention a magnetic coupler is provided in 
which sliding contact between two magnetic core members cleans debris off 
the mating surfaces of the core elements and ensures intimate contact 
between the core elements, thereby providing increased coupling 
efficiency. 
In another aspect of the present invention a method for coupling a pair of 
conductors utilizing at least two magnetic core members is provided. The 
method involves providing a first magnetic core member having at least one 
prong with a mating end surface and providing a second magnetic core 
member. The conductors are placed adjacent the first magnetic core member. 
At least one of the magnetic core members is moved to produce sliding 
contact between a portion of the second magnetic core member and the 
mating end surface of the first magnetic core member thereby cleaning 
debris off the mating end surface to provide intimate contact between the 
core members upon completion of the sliding contact. 
More particularly, in one embodiment the present invention includes an "E" 
core member and an "I" core member. The "E" core has three prongs with a 
pair of slots therebetween. The coupler further includes a shuttle to 
retain the "I" core, and a base to retain the "E" core member. The base 
includes a set of extensions each of which carries a flange at its end, 
and the extension together which form a guide in which the shuttle and the 
"I" core slide. In this manner the "I" core can slide from an open 
position in which the slots are exposed to a closed position in which the 
slots are covered by the "I" core member, and the conductors are retained 
within the coupler. When in the closed position, the shuttle forms an 
interference fit with the base to thereby retain the shuttle in place. The 
sliding action of the "I" core across the "E" core removes any build-up of 
debris on the exposed core elements, thereby providing clean intimate 
contact between the magnetic core elements. Furthermore, the coupler is 
easy to open and close. The coupler can be conveniently located in the 
desired position, and once so located, can be easily moved to the closed 
position with a single hand. To open the coupler, a screwdriver or other 
similar tool can be inserted into a slot in the coupler and used to slide 
the shuttle from the base. 
It is recognized that other embodiments of magnetic couplers or magnetic 
coupling systems which incorporate the sliding contact between core 
members of the present invention are possible without departing from the 
intended scope of the present invention. 
These and other objects and advantages of the present invention will be 
more fully understood and appreciated by reference to the following 
description, the accompanying drawings and the appended claims.

DETAILED DESCRIPTION 
As shown in FIGS. 1-3, a magnetic coupler 10 according to one embodiment of 
the present invention comprises a "E" core member 12, an "I" core member 
14, a base 16 for retaining the "E" core member 12, and a shuttle 18 for 
retaining the "I" core member 14. The base 16 includes a lattice 26 and a 
cover 28. In a preferred embodiment, a copper conductor 17 is fitted 
within the slots of the "E" core 12. The conductor 17 retains the "E" core 
12 within the base 16. The shuttle 18 receives the "I" core 14, and is 
slidingly connected to the base 16. The shuttle 18 may slide from an open 
position to a closed position, and its reciprocation is guided by the 
flanges 27 of the base 16. 
The "E" core member 12 and "I" core member 14 are formed of magnetic 
material to increase the induction efficiency between the electrical 
conductors. As used herein the term "magnetic core member" refers to a 
core member formed from a magnetic material, such magnetic material being 
a material having a relatively high permeability, such as materials which 
are commonly used as transformer cores or inductive sensor cores. The "E" 
core member 12 is preferably "E" shaped in profile, having three prongs 
20. Each prong 20 has a mating surface 13 which faces the shuttle 18, as 
shown in FIG. 1. The prongs 20 also define a pair of slots 22 (FIG. 3). 
Copper conductor 17 has a pair of parallel arms 37 which fit within the 
slots 22 of the "E" core. Each arm 37 terminates in a flange 39 which 
passes through the slot 50 of the cover 28. Conductor 17 further has a 
pair of generally rectangular cut-outs 55 and 57. Although the conductor 
17 is described herein as copper, those skilled in the art will appreciate 
that the conductor 17 may be made of any electrically conductive material. 
"I" core member 14 is generally rectangular in profile. However, the 
coupler of the present invention may use other shaped core members in 
place of the "I" core 14 or the "E" core 12. For example, a second "E" 
core member may be used in place of the "I" core 14 without departing from 
the scope of the present invention. Further, the "E" core 12 could be 
replaced with a "U" core and/or the "I" core could be replaced with a "U" 
core, any of such variations, as well as others, being apparent to one 
skilled in the art. 
As shown best in FIG. 3, the base 16 is comprised of a lattice 26 and a 
cover 28. The lattice 26 receives the "E" core member 12, and includes 
four parallel extensions 24. Lattice 26 further includes a pair of tabs 52 
extending along its ends, and a second pair of tabs 53 extending along its 
sides. The "E" core is received by the lattice 26, and copper conductor 17 
is then placed around the lattice 26. Cut-outs 55 and 57 fit around the 
tabs 53, thereby retaining the conductor 17 and the "E" core 12 within in 
the lattice 26. Base 16 further has a set of four extensions 24 extending 
generally perpendicular to the base 16 from each corner. Each extension 24 
terminates in an inwardly-extending flange 27, and the flanges 27 together 
comprise a guide 23. 
Cover 28 includes a generally rectangular plate 30, a pair generally 
rectangular side panels 32, and a pair of generally rectangular end panels 
34. The panels 32, 34 are oriented generally perpendicular to the plate 
30. Each end panel 34 has a finger 36 which is shaped to latch over a 
respective tab 52 of the lattice 26. In this manner, the cover 28 receives 
and retains the lattice 26 between the panels 32, 34. Cover 28 further 
includes a longitudinal cut-out 50 through which the flanges 39 of the 
conductor 17 may pass. 
Shuttle 18 is generally rectangular in top view and is shaped to receive 
the "I" core member 14. Shuttle 18 has a flexible clip 59 with an angled 
surface to retain the "I" core within the shuttle. Shuttle 18 also 
includes a leg 38, as well as a front ramp 43 and a rear ramp 45 located 
along its top edge 41 or upper surface. The front ramp 43 and rear ramp 45 
are raised surfaces that extend forwardly of the top edge 41 or upper 
surface. The front ramp 43 is adjacent the front edge of the shuttle, and 
the rear ramp 45 is adjacent the rear edge of the shuttle. 
As shown in FIG. 1 and FIG. 2, when fully assembled the magnetic coupler 10 
of the present invention comprises the shuttle 18 slidably mounted to the 
base 16. The shuttle 18 is received within the flanges 27 of the 
extensions 24. Thus, as the shuttle translates with the respect to the 
base 16, the inwardly-extending flanges 27 together comprise a guide 23 to 
direct the translation of the shuttle 18. Lower support flanges 65 (FIG. 
4) helps to retain the shuttle 18 within the base, and guides the 
translation of the shuttle 18. 
FIG. 2 shows the magnetic coupler 10 in its open position. The sliding path 
of the shuttle 18 from the open position to the closed position is 
indicated by the arrow A in FIG. 2. When in the open position, the slots 
22 are not covered by the "I" core member, and when the coupler is in the 
closed position the slots are covered by the "I" core. Leg 38 of the 
shuttle 18 limits the translation of the shuttle 18 to the right as shown 
in FIG. 1. Leg 38 extends generally perpendicularly to the path of the 
shuttle. The extensions 24 also extend in a direction generally 
perpendicular to the shuttle path. 
As shown in FIG. 5, the present invention preferably is used with a rail 
member 46 having an electrical conductor 47 contained therein. The rail 
member 46 has a plurality of slots 48 to receive central prong 20' of the 
"E" core 12. In this manner the conductor 47 and the conductor 17 may be 
magnetically coupled by the coupler 10. Once the "E" core is located in 
the desired position, the shuttle 18 may be moved to the closed position. 
For example, a worker using the coupler of the present invention may 
locate the coupler, by feel, such that the central prong 20 fits within an 
associated slot 48. While retaining the coupler in this position, the 
worker may then easily slide the shuttle 18 to the closed position using 
only a single hand. Thus, the present invention provides for a coupler 
that can be easily located and operated with only a single hand. 
When shuttle 18 is shifted to the closed position, the front ramp 43 and 
rear ramp 45 contact the respective flanges 27 as the shuttle nears the 
closed position. Due to the increased width of the ramps, the shuttle 18 
is frictionally engaged by the lattice 26. Also, the "E" core 12 and "I" 
core 14 are pressed into intimate contact due to the interference fit 
between the ramps 43, 45 and the flanges 27. In this manner, an improved 
connection between the E core and I core is maintained. Although 
configured for normally retaining the shuttle 18 within the base 18 when 
in the closed position, the inward extension of flanges 27 is preferably 
limited to allow the shuttle 18 to be pulled away from the base 16 if 
substantial separating force is present. In particular, extensions 24 are 
sufficiently flexible to be moved outward by the separating force to allow 
the shuttle 18 to pass by the flanges 27. The feature helps reduce 
potential damage in applications where such separating forces may be 
experienced when a person fails to move the shuttle 18 to the open 
position before making adjustments. 
In normal operation, the shuttle 18 may be uncoupled from the lattice 26 by 
inserting a screwdriver or other appropriately shaped tool into the slot 
79 of the shuttle 18. By pivoting the screwdriver against the cover 28 the 
shuttle can be slid to the open position. The coupler 10 may then be 
removed from the rail member 46, and the conductors thereby uncoupled. 
Additionally, the front ramp 43 acts so as to retain the shuttle 18 within 
the base 16 when the shuttle 18 is in the open position. When in the open 
position, the front ramp 43 is wedged between flanges 27 and a lower 
support flanges 65 (FIG. 4). The front ramps 43, flanges 27 and lower 
support flanges 65 cooperate so as to keep the shuttle from falling out of 
the base 16. 
Additionally, when the coupler 10 is moved from an open position as shown 
in FIG. 2 to the closed position as shown in FIG. 1, the movement of the 
"I" core member 14 across the prongs 20 of the "E" core member 12 
effectively removes debris from the mating surfaces 13. Beveled surface 49 
of the "I" core 14 acts so as to prevent the shuttle 18 from becoming 
jammed as it traverses the "E" core. Cleaning the cores makes coupling 
highly efficient and gives the resultant connection good balance and 
uniformity. 
While the invention should be useful in any application in which it is 
desired to magnetically couple a pair of conductors, it may be 
particularly useful in coupling loops to provide one or two-way 
communication between one or more terminals. Furthermore, although the 
invention is illustrated using a copper conductor and a rail member, it is 
to be understood that the coupler of the present invention may be used to 
couple a pair of loose wires, as is illustrated in FIG. 6. Alternately, 
the coupler 10 may be useful in coupling a loose wire to the copper 
conductor 17, or in coupling a loose wire to the rail member 46. The 
magnetic coupler 10 of the present invention may be used to couple, for 
example, branch distribution loops to main distribution loops. However, 
those skilled in the art will appreciate that the coupler 10 may be used 
at any point where conductor coupling is desired. 
While the forms of the apparatus herein described constitute a preferred 
embodiment of the invention, it is to be understood that the present 
invention is not limited to these precise forms and that changes may be 
made therein without departing from the scope of the invention. In 
particular, the base and shuttle of a coupler in accordance with the 
present invention could take on a variety of configurations which provide 
sliding contact between the core members. The base and/or shuttle could 
also be formed integral with other structures of a larger system. Still 
further, it is recognized that sliding contact between core members need 
not take place along the entire path of movement from the open to closed 
position of the coupler. For example, constructions in which the moving 
core member is pressed into sliding contact with the non-moving core 
member just prior to reaching the closed position are envisioned and are 
likewise considered within the scope of the present invention.