US1543529A - Electromagnetic measuring instrument - Google Patents

Description

June 23, 1925. 1,543,529

G. W. SPRENG-ER ELECTROMAGNETIG MEASURING INSTRUMENT Filed April 1l. 1924 Inventor-'I George Walter prel'wqer.`

His ATJLor'r-weg.

Patented .lune 23, 1925..

UNITED STATES PATENT OFFICE.

GEORGE WALTER SPRENGER, F LYNN, DIASSACHUSETTS, ASSIGNOR TO GENERAL ELECTRIC COMPANY, A. CORPORATION OF NEW YORK.

ELEcTnoMA'GNETIc MEAsUR-ING. TNSTEUMEN-r.

Appncauon fued Aprii 11, 1924. seria1 No. 705,957.

VTo all whom t may concern.:

Be it known that I, GEORGE WALTER SPRENGER, a citizen of the United States, residing at Lynn, in the county of Essex, State of Massachusetts, have invented certain new and useful Improvements in Electromagnetic Measuring Instruments, of which the following is a specification.

My invention relates to electric measuring instruments of the electromagneticV type and in particular to a novel arrangement for in-A creasing and adjusting the angle of deflection of such instruments.

The electromagnetic instrument is perhaps one of the simpl-est and oldest forms of'indi cating type instruments. Owing to the fact that the detiection is caused by the action of an electromagnet, generally a plunger magnet, acting against a spring, the defie'ction angle is fairly small and not very uniform. In United States Patent No. 394,728, there is described an instrument of this type where these defects are eliminated tosome extent by providing two plunger magnets with parf tially overlapping effects. My invention has for its object a further elimination of these defects and in addition an arrangement whereby the deliection angle may be readily adjusted and the instrument calibrated.

In carrying my invention into effect I use one or more plunger magnets and I make the winding of the operating solenoid or solenoids in a plurality of sections sep- 3 arated from each other. This arrangement without causing saturation of the iron core which forms the moving element and with? cooling of the coils. By properly adjusting -the relative positions of the severalsections of the solenoid windings, the deflection characteristics may be made very uniform over a considerable range of deflection.

Preferably, two solenoids are used and 'p45 arranged on opposite sides of the axis of rotation of the instrument and in this case corresponding coil sections of the two solenoids are preferably mounted on the opposite ends of relatively adjustable independent members pivoted on the axis of rotation so that in adjusting the coil sections of one solenoid, the coil sections ofthe other solenoid are similarly adjusted. j

The features of my invention which I be- 5 lieve to be novel and patent-able will be results in an elongation effect of the solenoid f pointed out in the claims appended hereto. For a better understanding of my invention, reference is made in the following description to the accompanying drawing, Fig. 1 of which shows a. top View of the essential p'art-s of a preferred embodiment of my invention as applied to a curve drawing instrument, and Fig. 2l showsa side view of the instrument of Fig. 1 omitting the chart supporting members. y

In the drawings, the movable part of the instrument comprises the S-shaped member 10 which is pivoted at its center and having curved magnetic core pieces 11 and 12 concentric to the axis of rotation. The movable member carries in this instance an inkwell 13 which is pivoted on the extremity of one of the radial arms. The inkwell carries a capillary pen arm 14 which dips into the inkwell and is secured in fixed relation the-reto.' The pen end of the arm 14 cooperrates with a suitable chartwhich is held on the supporting member 15. The penis held in contact with the chart by a small coiled spring l16 mounted between the pivoted inkwell and its support.V To counterbalance the weight of the inlwell an adjustable weight 17 lis provided on the movable member. The member 10 is urged to a Zero indicating position by a coiled spring 18 fixed between the member 10 and the stationary lower bearing posts 19 rising from the framework 20. Instead of being a curve drawing instrument, the instrument might be of a. simple indicating type and by the expression indicating type I intend to include curve drawing as well as purely indicating instruments and relays which incorporate the essentials of my invention.

rlhe stationary part of the instrument includes members 21, 22 and 23 which exten-d in opposite directions from the axis of rotation where they are supported by integral collars 24 rotatably mounted on the stationary post 19. Each of these members is separately adjustable about the postl 19 and they may be fixed in any adjusted position by lock screws 25. On the outer end of the members just described are mounted the coil sections 26 which, together, form the windings of the two solenoids with which the core pieces 11 and 12 cooperate. Each such member supports Vcorresponding coil sections of the two solenoids and by correspending sections I mean for example the first sections in each group. Thus the sections first threaded by the core pieces are corresponding sections. It so happens in the modication described that the correspond-c ing coil sections are diametrically opposite. The coil sections may all be connected in series, in parallel, or in series parallel, the only precaution necessary being to see that the coil sections o'l each solenoid produce linx in the same direction. The most desir'- able designs will generally result from a series connection of the coil sections.

It Will now be evident that the instrument will have a count-ercloclrwise deflection, as viewed vin Fig. l, dependent upon the strength of the current iiowing in the coils, the magnetic pull of the solenoids being opposed by the spring 18, and that the range of deflectionY fora given variation in the current strength may be made very small by bringing the coil sections close together or much larger by their separation. Furthermore, itvwill be evident that the deflection characteristics may be changed over a given range of deflection by separating certain adjacentcoils more or less than other adjacent coils.

' The parts going to make up the instrument may be made in large quant-ities and oi" a standard size Without taking any particular precautions to see that the individual parts conform to a definite standard since the deflection characteristics and the calibration of the instrument may be easily andv A readily altered as soon as the parts are assembled. The solenoid, although made up of standard coil sections oil cylindrical Jform, is sector-shaped con-forming to the circular shape of the core and this is advantageous 4because of the diliiculty of Winding sectorshaped coils. By separating the windings into sections in this Way, a higher current density can be maintained because ot the greater heat radiating surface which this construction provides.

Although I have shown three groups of coils going to make up a solenoid Winding and have shown two such solenoids, I do not Wish to be limited in this respect as my invention is not dependent on the number of solenoids used nor upon the number of coil sections per solenoid so long as more than one coil section is used for each solenoid and .respect to each other.

In accordance With the provisions of the patentf statutes, I have described the principle of operation of my invention, together with the apparatus which I now consider to represent the best embodiment thereof; but I desire to have it understood that the apparatus shown and described is only illustrative and that the invention can be carried out by other arrangements.

What I claim as new and desire to secure by Letters Patent of the United States,

1. An indicating instrument of the electromagnetic type having an operating plunger magnet the Winding of which is made up ot a plurality of separate coil sections Which are relatively1 adjustable with respect to each other along the axis of Vthe solenoid.

2. An indicating instrumentof' the electromagnetic type having a sector shaped operating solenoid forming the stationary part ot the instrument and made up lof a plurality of separate cylindrical coil sections arranged to be Vindependently adjustable along the axis of the solenoid.

3. In an indicating instrument of the electromagnetic type, a moving elementmade up of an S-shaped member pivoted at its center, the end portions of the member comprising sector shaped core pieces, -sector shaped solenoids forming the stationary part of the instrument positioned to be threaded by said core pieces, said solenoids being made up of a plurality of coil sections, the number of coil sections in each solenoidfbeingthe same, and independently adjustable supporting members pivoted on the axis of rotation of theS-shaped member -for supporting corresponding coil sections of each solenoid. y Y

4. An indicating instrument of the plunger magnet type having a sector shaped core member, supporting means therefor pivotedV for rotationabout the central axis of the sector, a relatively stationary solenoid mem'- bcr arranged to be threaded by said core, said solenoid member being made up of va plurality of coil sections,supporting members for each coil section, said supporting members being pivoted on the axis of rotation of the core member and independently adjustable about said axis.

In Witness whereof, I have hereuntoA set my hand this eighth day o'tl April, 1924.

GEORGE VALTER SPRENGER.

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