US2245493A - Electric indicating means - Google Patents

Description

June 10, 1941. E. NOTHE ELECTRIC INDICATING MEANS Filed Sept. 1, 1938 l lOMACrNET/C INVENTOR. BY %H%( 2 q T o R ix III //7 associated with sald core.

s Patented June 10, 1941 ELECTRIC INDICATING MEANS Erich Niithe, Berlin-Spandau, Germany, assig'nor to Siemens Apparate und Maschinen Gesell- Schaft mit beschriinkter Haftung, Berlin, Germany, a corporation of Germany Application September 1, 1938, Serial'No. 228,068

- In Germany September 25, 1937 4 Claims. (01.177-329) This invention relates to electric indicating means and more particularly to electromagnetically actuated rotary indicators for use in asso ciat-ion with, for example, the instruments upon the dashboard of a vehicle such as an aircraft.

One of the objects of the present invention is to provide novel means for indicating when an electric current is fiowing in an electric'lead or v flowing to an electrically actuated instrument.

Another' object of the invention-is to provide a novel indicator having a high sensitivity but capable of withstanding vibrations.

Another object is to provide a novel indicator having small dimensions.

A further object is to provide a novel electromagnetic device of the above character having a low magnetic leakage flux whereby adjacent instruments are-safe from the disturbing efiects caused by such leakage.

The above and further objects and novel features will more fully appear from the following detailed description when the same is read in connection with the accompanying drawing. It is to be expressly understood, however, that the drawings are for purposes of illustration only and are not intended as a definition of the limits of the invention, reference for this latter purpose beinghad tothe appended claims.

In the drawing, wherein like reference characters refer to like parts throughout the several viewsz" Fig. 1 is a plan view, with a top cover removed,

showing one embodiment of the present invention;

Fig. 2 is a side elevation in section taken substantially along line '2-2'of Figure 1;

plan view of the -above embodiment;

net. The. apparatus comprises a metallic coremember which-is surrounded by an exciter coil. An angularly shiftable armature is mounted upon said core adjacent suitable pole shoes which are The armature iscoaxial with the coil and so arranged with respect to the core and pole shoes that the lines of force existing between "the core; armature and pole shoes are substantially perpendicular to the coil axis. v

In the form shown in Fig. 2,,a cylindrical case III of a magnetic material is provided having upon the upper edge 10o thereof and formed integrally therewith, a pair of upwardly extending pole piecesI Ilb and I00. Pole pieces I01) and IIlc are diametrically opposed. I

An exciter coil II lies flat upon and is attached to the bottom of case I 0 and is connected in the circuit of an electric lead wherein it is desired to determine when a current is flowing.

From the bottom of case I0 a central core I2 extends above coil I I. The core is provided at the extremity thereof with a recess. IZa for a non-magnetic bearing portion I3 in which there is rotatably supported a shaft I4 which is coaxial with said core. Upon a hub I5 which is mounted upon said shaft there is mounted a flat non-- magnetic. indicator portion II; which supports above the coil II an armature I1. Indicator I6 is in the shape of a cross having four arms comprising sectors of circles. The indicator is to be read inassociation with a face plate to be later described. Armature I1 is in theform of a fiat ring portion having an inner annular flange I'Ia,

and a pair of arms Ill) and Ho extending outwardly from, and integral with, said ring portion. In order to increase the attraction between the pole pieces and the armature, arms Nb and Ho are provided atthe outer edges thereof with flange portions I8 and I9, respectively, said por-.

tions being movable adjacent the pole pieces 10b and IE0. The flange portions I8 and I9 vare tapered, i. e., they are in the shape of the outer surface of a sector of a cylinder formed between two intersecting planes which form an acute angle with one another. This flange formation makes it possible'for a progressively increasing flange area to move adjacent each pole piece as the armature is angularly displaced from its initial position: Consequently, the motor action or the attraction by the pole pieces will correspondingly increase with the angular displacement of and shape of the indicator portion I6. A'central bore in said face plate serves as an upper bearing for the armature shaft I4.

In order that the angularly shiftable armature I! may be yieldingly urged in a predetermined dithereof to hub l5 and bearing l3. When coil II is de-energized, spring 23 urges the armature against a limit-stop comprising an extremity 24a of a member 24.- The member 24 is constituted by a strip of non-magnetic material which conforms to the curvature of the inner surface of container I0. Member 24 is rigidly held in place' by means of a screw 25 (Fig. 1). An opposite extremity 24b of said strip serves as an abut- .able means better shown in Fig. 4, a more positive magnetic attraction may be obtained which will further reduce the sensitiveness of the device to vibrations and to sudden shock. Such a metal portion 26 is mounted adjacent the extremity 24b of limit-stop 24 (Fig. 1). The armature is magnetically tightly gripped by portion 26 when the indicator is in the on" position.

The visible portions of the indicator l6 are coated with a luminous substance, for example a phosphorescent paint or some radioactive material, in order to render these portions conspicuous.

In operation,-coil II is energized by connection to a suitable energy source (not shown). Armature I! is situated between the pole pieces lob and I 00 and the central core 12 in such a manner that thelines of force run substantially perpendicular to the axis of the electromagnetic device, i. e. the axis of coil II and core I 2. The armature is'attracted by said pole pieces and thus is angularly shifted against the pressure of spring 23 until flanges l8 and I9 are opposite the poles lflb and H10, respectively, at which time the armature will engage the portion 26 of limitstop 24b. The cross-shaped indicator I6 moves with the armature from the initial or oil position,when the indicator arms are covered by plate 21, to the on position where said arms are visible through perforations 22.

There is thus provided a novel indicating device wherein the moving parts are angularly but not longitudinally shiftable. The apparatus therefore is not sensitive to the ordinary longitudinal vibrations which occur, for example, aboard aircraft. When the electromagnet is energized, the lines of force are required to bridge only very short gaps. Consequently, the stray or leakage flux is reduced'to a minimum and the device will not electrically disturb such gauges, measuring nearby. The indicator is of small size and is adapted to fit within a small bore which may be drilled in a dashboard or panel.

departing'from the spirit and scope of the inapparatus and compasses, etc., which are located vention as the same will now be understood by those skilled in the art. For a definition oi the limits of the invention, reference.will be had primarily to the appended claims.

What is claimed is:

Lin 9. signal device of the current indicator type, the combination with a pair of pole pieces, of a central core, a coil coaxial with said core, an armature having depending means on its, outer periphery, non-magnetic means for mounting said armature for angular movement between zero and full scale positions on a shaft, said shaft being coaxial with. and supported by said core, means comprising a limit-stop provided with ends defining contact surfaces for said armature whereby during angular movement thereof the armature contacts one of said surfaces in its zero position and the other of said surfaces. at its full scale position, one contact surface only of said limit-stop means comprising a magnetic member, and means for yieldingly urging said armature against one surface of said limit-stop.

2. In a signal device a central core, an armature coaxial therewith, means supporting said armature upon said core for angular movement thereon between a zero and full scale position, an indicator member rigidly secured to said faces cooperates with said armature at its full.

scale position, the latter of said surfaces being provided with magnetic means.

3. In an instrument of the current indicator typ the combination with a pair of pole pieces, of a central core, a coil coaxial with said core, an armatureinsulated from and mounted for angular movement upon said core between a zero and full scale position, and means comprising a limit-stop provided with ends defining contact surfaces for said armature whereby during angular movement thereof the armature contacts one of said ends in its zero position and the other of said ends at its full scale position, one of said ends comprising a magnetic member connected with one of said pole pieces.

4. In an instrument of the current indicator type, the combination with a pair of pole pieces of a central core, a coil coaxial with said core,

an armature insulated from and mounted for .angular movement upon. said core between a zero and full scaleposition, said armature comprising a ring portionprovided with depending flanges surrounding said core and outwardly extendin arm members having tapered flanges at the outward ends thereof associated with said pole pieces, and means comprising a limit-stop provided with ends defining contact surfaces for said armature whereby during angular movement thereof the armature contacts one of said ends in its zero position and the other of saidends at its full scale position, one of said ends comprising a magnetic member secured with one of said pole pieces.

ERICH Nonin-

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