US3268840A

US3268840A - Magnetic switch contact assembly

Info

Publication number: US3268840A
Application number: US294516A
Authority: US
Inventors: Hjertstrand Svante Lennart
Original assignee: International Standard Electric Corp
Current assignee: International Standard Electric Corp
Priority date: 1961-02-01
Filing date: 1963-07-12
Publication date: 1966-08-23
Anticipated expiration: 1983-08-23
Also published as: GB945081A; GB1023518A; NL295616A; NL274258A; CH408125A; CH400248A; BE635146A; DE1194003B; US3099727A

Description

g- 23, 1965 s. HJERTSTRAND 3,268,840

MAGNETIC SWITCH CONTACT ASSEMBLY Filed July 12, 1963 FIG, 2

Inventor $.L. HJERTSTRAND y y rney United States Patent 3,268,840 MAGNETIC SWITCH CONTACT ASSEMBLY Svante Lennart Hjertstrand,.H'agersten, Sweden, assignor to International Standard Electric Corporation, New York, N.Y., a corporation of Delaware Filed July 12, 1963, Ser. No. 294,516 Claims priority, application Sweden, July 20, 1962', 8,082/ 62 5 Claims. (Cl. 335196) This invention relates in general to crossbar switchces and in particular to an improved contact assembly suitable for use in crossbar switches in which each contact set is selectively operable in response to the establishment of a magnetic attraction between the intersecting horizontal and vertical rows of contact multiples. This invention is an improvement on the crossbar switch disclosed in my copending U.S. patent application, Serial No. 167,506, filed January 22, 1962 and entitled Magnetic Crossbar Switch, now Patent Number 3,099,727.

In the noted application, a crossbar switch is provided in which the usual hold and select magnets and associated hold and select bars are replaced by magnetic elements extending co-axi-ally along flexible horizontal and vertical multiples. At each intersection of the noted multiples, one or more normally open contact plugs or contact points are secured to one or both multiples. Electrical contact is established between two intersecting multiples when the magnetic elements thereon are magnetized since the multiples fiex sutficiently to bring the contact plugs into contact with the adjacent multiple.

In certain application, such as electronic switching systems, the large amount of operating current necessary to operate the switch of the noted application rendered the use of such switches prohibitive. The reason for these large current requirements was due to the strength of the magnetic field necessary to flex the multiples to establish the noted electrical contact therebetween.

Accordingly, it is an object of the present invention to provide a magnetically operated contact assembly requiring a minimum of operating current.

It is another object to provide a contact assembly suitable for use in crossbar switches in which the horizontal and vertical multiples are immovable and thus may be fabricated from material less expensive than the flexible material used in known switches.

In carrying out the above objects, a contact plug made from magnetic material is loosely mounted between the intersecting multiples and arranged to move independently of the multiples when the multiples are magnetically energized.

Another object is to provide a contact assembly of the foregoing character in which the contact plugs comprise permanent magnets which have insuflicient flux to actuate the contacts but when aided by the noted magnetic energization of the associated multiples provide afast-acting switch.

Other objects and features relate to the provision of a suificiently large housing for the contact plugs to permit them to execute a rotating movement when magnetized to establish electrical connection.

Still further objects and features will become apparent and the invention will be best understood when the specification is read in conjunction with the accompanying drawings comprising FIG. 1 and 2 in which:

FIG. 1 shows two contact assemblies together with .a portion of the well-known intersecting horizontal and vertical contact multiples modified according to the invention; and

FIG. 2 shows one contact set having the contact plugs or points in operated condition and the other set in unoperated condition.

3,258,840 Patented August 23, 1966 Ice Referring now to FIG. 1 of the drawings, a description of the invention will be given.

The switch section illustrated comprises a horizontal contact multiple strip 1 and a pair of vertical contact

multiple strips

2 and 11. These multiple strips may be made of a flexible or rigid magnetic material which has good electrical conductivity. The multiple strips are arranged in horizontal and vertical rows with the horizontal and vertical strips being located in adjacent parallel planes. An operating conductor 5 is associated with multiple 1 and similar operating conductors such as 6 and 12 are associated with

corresponding multiples

2 and 11. An insulating strip 7 is positioned along the horizontal multiple 1 between the magnetic elements of the horizontal and vertical multiples. This insulating strip could be positioned along the

vertical multiples

2 and 11. In either case, this insulating strip includes a plurality of [apertures 13 located at the intersection of the horizontal and vertical multiples.

The noted apertures are of a diameter suflicient to loosely retain the contact plugs or points positioned between associated horizontal and vertical intersecting multiples. As seen most clearly in FIG. 2, the plugs may be small cylindrical elements of a length insufficient to establish electrical contact between adjacent multiples when the contact assembly is not energized, but sufficiently long to touch both multiples when tilted or rotated as shown in FIG. 2.

When multiple strips such as 1 and 2 are simultaneously magnetized, as by magnetic fields produced by current flowing through

operating conductors

5 and 6 or by magnetic fields induced in the operating conductors by associated coil means such as C1 and C2, the contact plugs 3 and 4 are attracted thereto resulting in a rotating movement which causes the ends of the plugs to establish electrical contact with one horizontal multiple such as 1 and one vertical multiple such as 2. Additional coils such as C3 and C4 can be used at various cross-over points.

When the magnetic elements are de-magnetized, the contact plugs returned to their normal position such as is shown in FIG. 2 for

contact plugs

9 and 10.

The contacting surfaces of the contact plugs may be covered with a precious metal in order to achieve good contact properties and contact pressures.

In order to enhance the speed of operation of the contact assembly, the contact plugs may be permanently magnetized. The degree of magnetism must be sufliciently small to preclude operation and permit restoration of the contact assembly when the magnetic elements such as 5 and 6 are de-magnetized.

While the contact assembly has been disclosed as embodied in a crossbar switch structure, it is to be understood that such assembly could be fully utilized in individual contact stackups.

While I have described above the principles of my invention in connection with specific apparatus, it is to be clearly understood that this description is made only by way of example and not as a limitation to the scope of the invention.

I claim:

1. A contact assembly comprising first and second contact strips lying a selected distance apart in separate parallel planes with the contact strip in one plane positioned normal to the contact strip in the other said plane, contact means positioned between the contact strips of said planes at the crossover point of the first and second contact strips, said contact means being made of conductive material and formed to have a length insufficient in a normal position to bridge the selected distance between the first and second contact strips, a selectively energizable operating conductor extending longitudinally of each of said contact strips for generating a magnetic field therealong, the simultaneous generation of a magnetic field in both of said operating conductors imparting rotational movement to said contact means to turn it from its normal position to enable it to bridge the selected distance and to establish electrical contact between the contact strips at the said crossover point.

2. In a contact assembly as set forth in claim 1 mounting means positioned between the said operating conductors at said crossover point for loosely supporting said contact means in said position between said contact strips for free rotational movement to establish the said electrical contact.

3. A contact assembly as set forth in claim 1, wherein said contact means are comprised of magnetic material.

said contact means comprise a permanent magnet.

5. A contact assembly as set forth in claim 4 wherein the magnetic flux of said permanent magnet contact means is insuflicient to cause movement thereof in the absence of said magnetic field in both of said strips.

References Cited by the Examiner UNITED STATES PATENTS 2,595,769 5/1952 Cooley ZOO-87 3,099,727 7/ 1963 Hjertstrand 200-87 10 3,226,604 12/1965 Dreyfus-Alain 317-137 BERNARD A. GILHEANY, Primary Examiner.

ROBERT K. SCHAEFER, Examiner.

B. DOBECK, Assistant Examiner.

Claims

1. A CONTACT ASSEMBLY COMPRISING FIRST AND SECOND CONTACT STRIPS LYING A SELECTED DISTANCE APART IN SEPARATE PARALLEL PLANES WITH THE CONTACT STRIP IN ONE PLANE POSITIONED NORMAL TO THE CONTACT STRIP IN THE OTHER SAID PLANE, CONTACT MEANS POSITIONED BETWEEN THE CONTACT STRIPS OF SAID PLANES AT THE CROSSOVER POINT OF THE FIRST AND SECOND CONTACT STRIPS SAID CONTACT MEANS BEING MADE A CONDUCTIVE MATERIAL AND FORMED TO HAVE A LENGTH INSUFFICIENT IN A NORMAL POSITION TO BRIDGE THE SELECTED DISTANCE BETWEEN THE FIRST AND SECOND CONTACT STRIPS, A SELECTIVELY ENERGIZABLE OPERATING CONDUCTOR EXTENDING LONGITUDINALLY OF EACH OF SAID CONTACT STRIPS FOR GENERATING A MAGNETIC FIELD THEREALONG, THE SIMULTANEOUS GENERATION OF A MAGNETIC FIELD IN BOTH OF SAID OPERATING CONDUCTORS IMPARTING ROTATIONAL MOVEMENT TO SAID CONTACT MEANS TO TURN IT FROM ITS NORMAL POSITION TO ENABLE IT TO BRIDGE THE SELECTED DISTANCE AND TO ESTABLISH ELECTRICAL CONTACT BETWEEN THE CONTACT STRIPS AT THE SAID CROSSOVER POINT.