US2207064A - Oscillograph galvanometer - Google Patents

Description

July 9, 1940 J. A. MAURER, JR 2,207,064

OS CILLOGRAPH GALVANOMETER Filed Aug. l0, 1938 2 Sheets-Sheet l as a7 4 FIG l l? l2 a4- 38\ /39 Mme@ 444/ 'Y Y Mafer/a/w3o"`\ B2b 23 55 l215 INVENTEIR July 9, 1940- J. A. MAUER, JR 2,207,064

OSCILLOGRAPH GALVANOMETR Filed Aug. l0, 1938 2 Sheets-Sheet 2 29 o. @gama/z* ree/ 54 k.Brass l a. www@ INVENTEJR Patented July 9, 1940 UNITED STATES PATENT OFFICE OSCILLOGRAPl-I GALVANOMETER John A. Maurer, Jr., New York, N. Y., assignor to The Berndt-Maurer Corp., New York, N. Y., a corporation ol New York This invention relates to devices whichtranslate alternating electric current signals into corresponding oscillations of a. beam'of light, and has for its principal object the provision of an improved oscillograph galvanometer suitable for use in connection with recording sound on iilm, picture transmission, and the like.

Other objects of the invention are the provision of an voscillograph galvanometer which lends itself readily to standard manufacture, which is rugged in structure and of uniform performance over long periods of service and which needs no adjustment once it is properly assembled, but which at the same time is of improved eiiiciency 1;, in response and `of improved fidelity in-translation. These results are substantially achieved by employing a small number of elements and adapting as many of them as possible to be -formed by punch press operations, by making the whole structure compact, by inserting in the field magnetic circuit of the device an air gap which is easily adjustable, by accurately controlling the length of the air gaps that separate the armature from the pole pieces, and by various other features which 'are set forth in the following description.

'Ihe invention will be better understood when the following description is considered with the accompanying drawings, and its scope will be pointed out in the appended claims.

Referring to the drawings:

Fig. 1 is a. longitudinal section of an oscillograph galvanometer according to the invention.

Fig. 2 is a perspective view of certain elements thereof.

FiFig. 3 isan elevation of the left-hand end of g. l. f

Fig. 4 is a section on line 4-4 of Fig. 1.

Fig. 5 is a section on line 26 of Fig. 1.

Fig. 6 shows another oscillograph galvanometer according to the invention; the shell being broken away, and the elements being shown in top view.

Fig. 7 is an elevation of the right-hand ends of Figs. 1 and 6.

Referring rst to Figs. 1 to 5 inclusive, there is shown a shell lll, containing the other elements of the oscillograph galvanometer. Shell Ill is made of magnetic material, for example, of steel, and may preferably have rectangular sides and square 50 faces as shown. The interior Il of shell l0 is cylindrical but has two different diameters, so

that a shoulder I2 is formed within the shell l0. A pair of pole pieces and-2l and a yoke 22,

.magnetically connecting them together, are made 55 up by assembling laminae 23, 23, of mag- Aers 24,24,

netic material and of suitable shape, for example, ofA U-shape as shown in Figs. 1 and 2, as a bundle, and inserting them with a press iit into an aperture 24a of corresponding size in a stack of wash- The laminae 23 may preferably consist of silicon steel punchings, and the washers 24 are made of non-magnetic material, for example, brass.

The stack of washers 24 is inserted with a press l t into the larger portion of the interior of shell I0 and seated against the shoulder I2 therein so as to hold the laminae 23 within the shell l0. The dimensions of the parts are so chosen that the plane, in which pole pieces 20 and 2l' end and which is indicated in Fig. 1 by the broken line 25, is a short distance inside the plane 0f the face of shell I0, which is indicated in Fig.1 by the line 26; line 26 denoting at the same time the back face of the armature support 4I.

A mounting block 30 of magnetic material is threaded into the opposite end of shell l0 and is on its outer face, provided with a slot 3| or similar means to receive the blade of a screwdriver or the like for adjusting its position within shell I0. The pole 32a of a permanently magnetized element 32, conveniently of cylindrical form, is mounted in a correspondingly shaped recess 33 in the inner face of block 30. 'Ihe permanent magnet 32 may be made of steel or preferably of any one of several magnetic materials now available which have high coercive force, such as 35% cobalt steel or the alloys of aluminum, nickel, and cobalt.

The exposed pole 32h of the magnet 32 is faced by the yoke 22, that is, the bottom end of the bundle of laminae 23, and the distance between yoke 22 and pole 32h may be adjusted with cony siderable accuracy by screwing block 36in or out. Thus, yoke 22 and pole 32b are separated by an adjustable air gap 34, by the adjustment of which the field strength of the oscillograph galvanometer Vcan readily be controlled.

In a simpliiied arrangement, shown in Fig. 6, a permanent magnet 29 is Iixedly mounted within the shell I0 so that its pole 29a is magnetically connected to the shell I0. This may be accomplished, for example, by giving to the magnet 29 a shape somewhat like a mushroom, as shown, and inserting it with a press fit into that end of shell l0 which has the narrower internal diameter, so that its exposed pole 29h touches or comes close to yoke 22.l Thus, air gap 34 may be dispensed with or may be given a denite length,

and a device is obtained which still will yield satisfactory results, though it-.will not give quite as good performance as though the adjustable air gap 34 were provided in the manner described above.

A bi-polar winding 35 is mounted on a suitable support and placed over the pole pieces 20 and 2l, that is, the arms of the bundle of laminae 23. The ends 36 and 3l of the winding 35 leave the shell I0 through holes 38 and 39, and are connected to the source of the alternating signal currents.

On that face of shell I0 near which the pole pieces 20 and 2| terminate, there are provided holes 40, shown in Fig. 5, threaded to receive screws that secure the armature support to this face of shell l0.

The armature may be made integral with its support, as shown in Fig. 7, wherein the armature support 4I is a square plate of magnetic material, for example, thin steel, preferably silicon steel. Holes 42 are provided for the insertion of the screws 40a. that enter the holes 40 on the face of shell I for securing the support 4I to the shell l0. The armature 43 and the two torsion arms 44, 45, on which it is suspended, are obtained by cutting out from the plate 4l the two apertures 46, 41. A mirror 48 is mounted on the side of armature 43 turned away from the pole pieces 2D and 2|, or this side of armature 43 may be polished and rendered reflecting by any suitable means, such as plating.

When the support 4l is fastened to the shell l0 the armature 43 is supported so that its ends 50 and 5| are symmetrically located opposite the poles 52 and 53 of pole pieces 20 and 2l, that is, the unsupported ends of the bundle of laminae 23, when no signal currents are being applied to winding 35. The air gaps 54 and 55 separating the ends 50 and 5l of the armature 43 and the poles 52 and 53 can be controlled, when the shell l0 and the stack of washers 24 holding the laminae 23 have been nally assembled, by grinding or lapping the face of shell l0 to a plane surface, and at the same time grin-ding oil the poles 52 and 53, so that their plane indicated by the dotted line 25 in Figs. 1 and 6 will be the required distance below the plane of the face of shell l0, indicated by the line 2B in Figs, 1 and 6. 'I'he distance between planes 25 and 26 can be measured very accurately by means of a micrometer depth gauge or the like, and this distance once established is not subject to errors arising from any subsequent assembling operations.

The above description is merely to illustrate certain presently preferred embodiments of the invention,` and many other ways of carrying it out will readily suggest themselves to those skilled in the art. 'Ihe invention, therefore, is not to belimited, except in so far as is necessitated by the prior art and by the spirit of the appended claims.

What is claimed is:

l. An oscillograph galvanometer including a shell of magnetic material; a mounting block of magnetic material threaded into one end of said shell and adapted to be screwed in and out of said shell; a permanent magnet having two poles and secured by one of said poles on the inner face of said block; a stack of non-magnetic washers mounted within said shell; a bundle of U- shaped laminae of magnetic material inserted into said stack of washers, the bottom end of said bundle of laminae facing the other pole of said permanent magnet; a bi-polar winding placed over each arm of said bundle of laminae; a support of magnetic material secured to the other end of said shell; and an armature supported by said support opposite the unsupported ends of said bundle of laminae, the ends of said armature and said unsupported ends being separated by air gaps.

2. An oscillograph galvanometer including a. shell of magnetic material; a permanent magnet having two poles and mounted within said shell, one of said poles being magnetically connected to one end of said shell; a pair of pole pieces magnetically connected together an'd held by non-magnetic means within said shell, their magnetic connection facing the other pole of said permanent magnet; means for adjusting the distance between said magnetic connection and said other pole of said permanent magnet; a bi-polar winding placed over said pole pieces; a support of magnetic material secured to the other end of said shell; and an armature supported by said support opposite the poles of said pole pieces; the ends of said armature-and said poles of said pole pieces being separated by air gaps.

3. In an oscillograph galvanometer a permanent magnet having two poles; a pair of pole pieces magnetically connected together with their magnetic connection facing one of said poles; and means for adjusting the distance between said magnetic connction and said pole.

4. An oscillograph galvanometer including a shell of magnetic material; a permanent magnet havingtwo poles and mounted within said shell, one of said poles being magnetically connected to one end of said shell; a pair of pole pieces magnetically connected together and held by nonmagnetic means within said shell, their magnetic connection facing and separated by4 an air gap from the other pole of said permanent magnet; a bi-polar winding placed over said pole pieces; a support of magnetic material secured to the other end of said shell; and an armature supported by said support opposite the poles. of sai-d pole pieces, the ends of said armature and said poles of said pole pieces being separated by air gaps.

5. In an oscillograph galvanometer a permanent magnet having two poles; and a pair of pole pieces magnetically connected together with their magnetic connection facing and being separated by an air gap from one of said poles.

6. An oscillograph galvanometer including a shell of magnetic material; a permanent magnet having two poles and mounted within said shell, one of said poles being magnetically connected to one end of said shell; a pair of pole pieces magnetically connected together and held by nonmagnetic means within said shell, their magnetic connection facing and touching the other pole of said permanent magnet; a bi-polar winding placed over said pole pieces; a support of magnetic material secured to the other end of said shell; and an armature supported by said support opposite the poles of said pole pieces,

vthe ends of said armature and said poles of said pole pieces being separated by air gaps,

JOHN A. JR.

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