US2908783A - Electromagnetic devices - Google Patents

Description

oct. 13,' 1959 P. E. UGN 2,998,783

ELECTROMAGNETIC DEYICES Filed Jan. 13, 1956 FIGI. F|G 2.

pierre l/gon By MM ELECTROMAGNETIC DEVICES Pierre Eugne Ugon, Sceaux, France Application January 13, 1956, Serial No. 559,053

Claims priority, application France January 25, 1954 1 Claim. (Cl. 200-93) The present invention relates to electromagnetic actuating devices and is a continuation-in-part of my copending application Serial No. 483,101.

The aforementioned application relates to electromagnetic actuating devices comprising an electromagnet associated with a movable armature and arranged so that energization of the magnet winding by an electric current produces movement of the armature due to magnetic attraction or repulsion and movement of the armature performs some additional electrical or mechanical operation. For example, movement of the armature may control the opening or closing of switch contacts in an electrical circuit, in which case the device operates as an electrical relay, or alternatively movement of the armature may control` some mechanical operation such as the locking or releasing of a member.

According to the aforementioned application, an electromagnetic actuating device comprises essentially a core of magnetic material having associated therewith an exciting coil or winding adapted to be energized by an electric current -to form a substantially closed electromagnetic circuit, and an armature of soft iron or the like mounted for rocking movement about an axis between two free and opposite poles of said circuit and arranged to form a part of the magnetic path of said circuit, in such a manner that, when said coil is energised, the said two opposite poles act on portions of said armature on opposite sides of said axis with forces being equal and opposite to each other and at right angles to the faces of said poles, thereby producing a couple acting on the armature to turn it about said axis. By the static as well as magnetic balance of the armature, which may be of extremely small weight, and proper biasing by a balance spring or the like, the moving parts are highly insensitive against outside accelerating forces, such as mechanical shock and vibration, thus preventing undesired operation of the relay or like device in practically any position during use.

It is an object of the present invention to provide improvements in such electromagnetic actuating devices.

It is a further object of the present invention to provide a form of the electromagnetic actuating device which may operate as a polarised relay.

In order that the invention may be more fully understood, reference will now be made to the accompanying drawing, in which:

Figure l shows diagrammatically, an electromagnetic device arranged according to the aforementioned copending application,

Figure 2 reproduces the iixed magnetic circuit of Figure l with the addition of a polarising member according to the present invention,

Figures 3, 4 and 5 show similar views of three modiications,

Figure 6 shows a detail applicable to the modification of Figure 4, and

Figure 7 shows an anti-bounce contact arrangement States arent fine Patented Oct. 13, 1959 which possesses particular advantages for certain relays controlling electrical circuits.

Referring to Figure 1, the electromagnetic device arranged according to the aforementioned application comprises a central core 1 of magnetic material which is divided into two lateral branches 2. Between the central magnetic core 1 and the lateral branches 2 is located an electrical energising winding 3. A thin platelike armature 4 of soft iron, which can pivot about an axis 7, and which is associated with a restoring spring 7a, is arranged so that it is enclosed within the fixed magnetic system provided by the elements 1, 2 and 3. Two very narrow air gaps separate respectively the two opposite ends of the armature 4 from the pole piece 1a formed on the free end of the core 1, and the opposite pole piece 5. The pole pieces 1a and 5 are so arranged as to present a pair of laterally spaced parallel pole faces to the opposite end surfaces of the soft iron armature 4. p

The entire magnetic circuit may be solid or laminated but preferably iron laminations are employed.

Figure 2 shows a magnetic circuit for producing a polarised relay according to the present invention in which it is sufficient to replace the counter pole 5 by a permanent magnet 5a in order to create in the magnetic circuit a permanent flux super-posed on the variable iiux produced by the excitation of the core 1 by the coil 3. In this way the original magnetic circuit has only had to be modified slightly over the particular arrangement of the aforementioned application so that the apparatus possesses all the inherent advantages of the polarised relay, amongst which may be mentioned notably the effects of detection peculiar to this class of relay, and the facility of being able permanently to position their operating point in the region of their characteristic, which provides the greatest sensitivity.

Amongst the materials which may form the magnetic member 5a, ferrites are particularly recommended by reason of their high and strong coercive field and consequently their resistance to demagnetization, so weak whatever be the thickness in the direction of the magnetic field.

Figure 3 shows how the member 5a may be adapted to a fixed magnetic circuit arranged to receive a bent armature 4 as described in the aforementioned application.

In the modification of Figure 4 the permanent magnet has the form of a fiat disc 8 and its arrangement under the excitation winding 3, necessitates a break between the central core 1 and its base, at least in the arrangement which has been shown in Figure 4 and which has been further shown in Figure 6. The ferrite disc in these two gures may be in the form of a truncated pyramid or any other form offering the advantage of directing.1 the magnetic lines of force towards the core of the co1 In Figure 6, in which the coil 3 is removed, there is shown one of the many means which may be employed to re-establish the continuity of the central magnetic circuit by intimately joining the ferrite disc 1 to the laminations forming the central core 1 as well as to the lateral branches 2 from which they have been separated.

Furthermore, Figure 4 shows the elements, 1, 2, 3 and 8 separated by spaces, whilst once the arrangement is complete, no space exists between the elements and the continuity of the entire magnetic circuit must be assured after a cut has been made in the course of manufacture at the base of the central core 1.

Other known devices applicable to magnetic circuits may also be employed with advantage for such connections in order to give to them the highest permeability.

t p A U 2,908,783

In some embodiments of the invention, use may also be made of anti-bounce devices of the type indicated in Figur-e 7. This figure shows two relay contacts, comprising on the one hand a movable contact 10 mounted on the armature 4 turning about its` axis 7, and on the other hand the contact 1li Vmounted on its flexible blade 19, of which the bent end 19a rests slightly on a rigid part 20 in the state of rest. When the movement of the armature causes the contacts 10 and 11 to engalge, the blade 19 is ilexed and the rubbing of its end 19a on the surface 20a of the rigid part 20 quickly dissipates the energy of the shock so that it does not produce any rebound or vibrations. After the shock the contact carrying blade 19 returns aperiodically to its rest position, but the rubbing, which acts as a brake, tends towards zero, as the blade approaches its rst position such that it cannot be displaced or modied in the course of repeated operations of the relay.

I claim:

An electromagnetic device, comprising a core of magnetic material having three limbs, the central and at least one outer limb providing a substantially closed magnetic circuit having two opposite poles spaced from each other, an electric excitation winding associated With said core, a mechanically balanced armature mounted for rocking movement about an axis within the magnetic field produced between said two poles and having its opposite ends opposed, each by one of the pole faces which are arranged to exert equal magnetic forces on opposite sides of said armature thereby producing a couple acting on the armature to rotate it about said axis, an electrical contact assembly comprising a rst contact member and a second contact member, means for mounting the rst contact member as an arm extending from the armature so that it can move into and out of engagement with said second contact member upon movement of said armature, said second contact member comprising a rigid support and a ilexible blade mounted on and parallel to the rigid support and carrying a contact which is engaged by theriirst` contact member and a bent end portion to said flexible blade which bears on the rigid support, the arrangement being such that When the contact of said second contact member is enlgaged by the iirst contact member, the bent end portion rubs along the rigid support thereby quickly dissipating theenergy of the `shock of engagement and absorbing any bounce or vibration.

References Cited in the file of this patent UNTTED STATES PATENTS 1,624,476 Cummings Apr. 12, 1927 1,676,340 Lindner July 10, 1928 1,748,219 Hanel Feb. 25, 1930 2,203,727 Herbst June 1l, 1940 2,253,856 Harrison Aug. 26, 1941 2,277,111 Johnson Mar. 24, 1942 2,290,725 Bartels July 21, 1942 25 f 2,455,049 Edwards et al. Nov. 30, 1948 2,483,658 Miller Oct. 4, 1949 2,539,547 Mossman et al. June 30, 1951 2,609,462 Joseph Sept. 2, 1952 2,702,841 Bernstein Feb. 22, 1955 2,710,365 MacDougall et al. `lune 7, 1955 2,735,045 Savoie Feb. 14, 1956 2,741,728 Distin Apr. 10, 1956 2,810,039 Every Oct. 15, 1957

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