US3831124A

US3831124A - Magnetic core apparatus

Info

Publication number: US3831124A
Application number: US00413878A
Authority: US
Inventors: Alessio A D
Original assignee: Bell Telephone Laboratories Inc
Current assignee: AT&T Corp
Priority date: 1973-11-08
Filing date: 1973-11-08
Publication date: 1974-08-20
Anticipated expiration: 1991-08-20

Abstract

A magnetic core apparatus includes two arcs of magnetic material which are rotatably mounted with respect to each other within a holder. The arcs can be rotated into alignment for placement about conductors not having accessible ends and then locked thereabout by rotating the arcs out of alignment.

Description

United States Patent [19.]

DAlessio [111 7 3,831,124 [451 Aug. 20, 1974 MAGNETIC CORE APPARATUS [75] Inventor: Alfonso Joseph DAlessio,

Rockaway, NJ.

[73] Assignee: Bell Telephone Laboratories Incorporated, Murray Hill, NJ.

22 Filed: Nov. 8, 1973 211 App]. No.: 413,878

[52] US. Cl. 335/298, 336/176 [51] Int. Cl. H01f 3/00 [58] Field of Search 335/296, 298; 336/175, 336/ 176 [56] References Cited UNITED STATES PATENTS 2,291,013 7/1942 Wheeler 336/176 X 7/1949 Smith 336/176 X 4/1973 Schweitzer 336/176 X Primary Examiner-George Harris Attorney, Agent, or Firm-A. D. Hooper ABSTRACT A magnetic core apparatus includes two arcs of magnetic material which are rotatably mounted with respect to each other within a holder. The arcs can be rotated into alignment for placement about conductors not having accessible ends and then locked thereabout by rotating the arcs out of alignment.

7 Claims, 5 Drawing Figures BACKGROUND OF THE INVENTION 1. Field of the Invention This invention relates to magnetic core apparatus and more particularly to a magnetic core adapted for installation about conductors having no accessible end.

2. Description of the Prior Art There are many applications where magnetic cores must be installed around conductors and the like which have no readily accessible end over which the magnetic core can be slipped. In such applications the conductors must either be disconnected to provide an accessible end or the magnetic core must be segmented to allow its installation about the conductors. A common practice has been to segment the core into two 180 degree parts or arcs which are then installed about the conductors in an abutting end-to-end configuration by a suitable bracket'or other mounting means. Such an arrangement has disadvantages including the relatively long time required for installation of the mounting brackets because of the numerous parts involved and the relatively poor magnetic coupling between the abutting ends of the two segments.

Accordingly, it is an object of this invention to provide a magnetic core apparatus which can be quickly installed about conductors having no accessible end.

Another object is to simplify magnetic core apparatus for installation about conductors having no accessible end.

SUMMARY OF THE INVENTION The foregoing objects and others are achieved in accordance with this invention by a magnetic core which includes two circular arcs of magnetic material. Each arc has a groove in a face thereof anda rail such as an arc of low friction material is mounted in the groove so that the arcs mate together but can rotate with respect to each other on the rail. An arc snap ring snaps around the assembled magnetic arcs. The ring includes two upstanding flanges which hold one are and the rail stationary with respect thereto but allows the other are to rotate with respect thereto. The rotatable arc is rotated into alignment with the stationary arc to form a gap and permit installation of the core about a cable. Then the rotatable arc is rotated in the ring as much as 180 with respect to the stationary arc to close the gap thereby locking the core about the cable and providing a substantially continuous circular magneticpath about the cable.

BRIEF DESCRIPTION OF THE DRAWING The invention will be more fully comprehended from the following detailed description and accompanying drawing in which:

FIG. 1 is a perspective view of two magnetic arcs mounted in alignment with each other;

FIG. 2 is a perspective view of a snap ring or holder for mounting about the arcs of FIG. 1;

FIG. 3 is a perspective view of the ring of FIG. 2 installed about the arcs of FIG. 1 whichremain in an aligned configuration; v 2

FIG. 4 is a perspective view similar to FIG. 3 with the are slightly rotated with respect to each other; and

FIG. 5 is a perspective view similar to FIGS. 3 and 4 with the arcs rotated approximately with respect to each other.

DETAILED DESCRIPIION' FIG. 1 shows two

arcs

2 and 4 of a magnetic material aligned with each other so as to produce a gap 6 between the ends thereof through which a continuous conductor or the like can be inserted into the interior or center cavity 8 of the

arcs

2 and 4.

Arcs

2 and 4 have angular dimensions greater than 180. Advantageously the dimensions of

arcs

2 and 4 can be in the neighborhood of 300 so that gap 6 has an angular dimension of approximately 60 when

arcs

2 and 4 are aligned as shown. The desired dimension of gap 6 will of course depend upon the size of the cable or other object about which

arcs

2 and 4 are to be placed. The angular dimensions of

arcs

2 and 4 are made as large as possible consistent with this desired dimension of gap 6.

Arcs

2 and 4 can be made identical to each other if desired to obtain manufacturing economies.

The mating faces 10 and 12 of

arcs

2 and 4, respectively, are smooth and planar to allow close mating for good magnetic coupling therebetween. Each

face

10 and 12 has an

arcuate groove

14 and 16, respectively, therein extending the full angular extent of the face. Mounted within

grooves

14 and 16 is a rail or arcuate member 18 which has an angular dimension equal to that of

arcs

2 and 4. Rail l8 advantageously comprises an arc of low friction material such as the synthetic resin polymer commercially available under the trademark TEFLON which allows

arcs

2 and 4 to readily rotate with respect to each other along rail 18. The outer face 22 of arc 4, and also the outer face 20 of are 2 if the arcs are identical includes small depressions or dimples 24 therein for purposes to be subsequently explained. The

inner surfaces

44 and 46 of

arcs

2 and 4, respectively, include grooves or

recesses

45 and 47 spaced approximately 180 apart thereabout for uses to become clearer subsequently.

FIG. 2 shows a holder or snap ring 30 which is adapted to hold

arcs

2 and 4 in mating relationship on rail 18. Ring 30 includes an arcuate flange or wall 32 having upstanding ribs or fingers 34 along both edges thereof. Wall 32 advantageously has an angular dimension substantially equal to that of

arcs

2 and 4. Wall 32 includes two upstanding tabs 36 on the ends 38 thereof which extend slightly less than half way across the width 40 of wall 32 to prevent are 4 from rotating with respect to holder 30. Two of the upstanding fingers 35 along one edge of wall 32 include beads or protrusions 42 formed thereon and adapted to mate with dimples 24 on are 4 to provide a further locking or detenting action therewith. The outside surface 48 of ring 30 includes two hubs or ridges 49 which are adapted to fit within

grooves

45 and 47 when these grooves are aligned to provide a locking or detenting action for locking

arcs

2 and 4 in position'with respect to each other. I-Iubs 49 are located approximately 180 degrees apart on surface 48. Ring 30 advantageously can be formed from a spring metal.

Ring 30 is placed within center cavity 8 so that the

inner surfaces

44 and 46 of

arcs

2 and 4, respectively, lie along the outside surface 48 of wall 32 with fingers 34 upstanding along

outer faces

20 and 22 to hold

arcs

2 and 4 in mating relationship on rail 18 as is shown in FIG. 3. Tabs 36 contact the end faces 52 of are 4 and a portion of rail 18 and beads 42 mate with dimples 24 to hold or lock arc 4 and rail 18 stationary with respect to ring 30. Tabs 36 do not contact the end faces 50 of are 2. Thus arc 2 can rotate with respect to ring 30, arc 4 and rail 18 along the rail 18 while faces 10 and 12 remain in close mating contact. When

arcs

2 and 4 are aligned with each other, i.e., when the end faces 50 and 52 lie in substantially the same plane, hubs 49 also mate with

grooves

45 and 47 to provide a detenting or locking action to hold

arcs

2 and 4 aligned. Thus the arcs can be placed about a continuous cable or the like by passing the cable through slot or gap 6.

After

arcs

2 and 4 are placed about the cable, gap 6 is closed by applying a moment to are 2. When sufficient moment is applied, the detent force between hubs 49 and grooves 45 in arc 2 is overcome allowing arc 2 to rotate on rail 18 with respect to are 4 as shown in H0. 4. Arc 2 advantageously is rotated 180 at which time grooves 45 and 47 are again aligned and hub 49 again engages these grooves to lock the arcs about the cable with gap 6 closed and with a substantial area of contact between

arcs

2 and 4 to provide good magnetic coupling therebetween as shown in FIG. 5.

The magnetic core apparatus of this invention can quickly and easily installed or removed from cables by a twisting motion which moves

arcs

2 and 4 into and out of alignment as required. This offers significant economies over existing split core apparatus.

The close mating of

arcs

2 and 4 along

faces

10 and 12 and the substantial angular dimension of these arcs provides very good magnetic coupling between the arcs so that the arcs present a substantially continuous circular magnetic path about an enlcosed cable. This is a significant advantage over split core apparatus which present magnetic path discontinuities at abutting ends of arcs of relatively small angular dimensions.

While the invention has been described with reference to a specific embodiment thereof, it is to be understood that various modifications thereto might be made without departing from the spirit and scope of the following claims.

What is claimed is:

1. Magnetic core apparatus adapted for installation about conductors having no accessible end, comprising, in combination:

first and second arcs of magnetic material each having an angular dimension of greater than 180 each of said arcs including a substantiallyplanarface having an arcuate groove therein; an arcuate rail installed in said grooves for rotatably mounting said arcs with respect to each other with said planar faces in opposing mating relationship; and I a holder mounted about said arcs for holding said arcs in said mating relationship and including two upstanding flanges thereon which hold said first arc and said rail stationary with respect to said holder while permitting said second arc to rotate with respect to said holder, whereby said second arc can be rotated into alignment with said first arc to produce a gap by which said apparatus can be installed about said conductors, and said gap can be closed by further rotation of said second arc.

2. Apparatus in accordance with claim 1 wherein said angular dimension of said arcs is substantially 300.

3. Apparatus in accordance with claim 1 wherein said arcs include interior surfaces contacting said holder and having depressions formed therein, and said holder includes protrusions thereon adapted to mate with said depressions and hold said arcs in preselected positions with respect to each other.

4. Apparatus in accordance with claim 3 wherein said depressions and said protrusions are spaced 180 apart on said'arcs and said holder, respectively, so that said arcs can be held in first and second positions wherein said gap is fully open and fully closed, respectively.

5. Apparatus in accordance with claim 1 wherein said rail comprises an arc of low friction material to facilitate rotation of said arcs with respect to each other.

6. Apparatus in accordance with claim 1 wherein said holder comprises an arcuate wall having an angular dimension substantially the same as said angular dimension of said arcs, and upstanding fingers along the edges of said wall for receiving said arcs therebetween to hold with respect to said holders.

Claims

1. Magnetic core apparatus adapted for installation about conductors having no accessible end, comprising, in combination: first and second arcs of magnetic material each having an angular dimension of greater than 180* each of said arcs including a substantially planar face having an arcuate groove therein; an arcuate rail installed in said grooves for rotatably mounting said arcs with respect to each other with said planar faces in opposing mating relationship; and a holder mounted about said arcs for holding said arcs in said mating relationship and including two upstanding flanges thereon which hold said first arc and said rail stationary with respect to said holder while permitting said second arc to rotate with respect to said holder, whereby said second arc can be rotated into alignment with said first arc to produce a gap by which said apparatus can be installed about said conductors, and said gap can be closed by further rotation of said second arc.

2. Apparatus in accordance with claim 1 wherein said angular dimension of said arcs is substantially 300*.

4. Apparatus in accordance with claim 3 wherein said depressions and said protrusions are spaced 180* apart on said arcs and said holder, respectively, so that said arcs can be held in first and second positions wherein said gap is fully open and fully closed, respectively.

6. Apparatus in accordance with claim 1 wherein said holder comprises an arcuate wall having an angular dimension substantially the same as said angular dimension of said arcs, and upstanding fingers along the edges of said wall for receiving said arcs therebetween to hold said arcs in said mating relationship on said rail.

7. Apparatus in accordance with claim 6 wherein said fingers contact said arcs along exterior surfaces thereof, said exterior surfaces including depressions formed therein, and selected ones of said fingers include dimples therein for mating with said depressions in one of said arcs for holding said one arc stationary with respect to said holders.