US2492067A - Electric micrometer system - Google Patents

Description

1949 H. c. SCHILDMEIER ELECTRIC MICROMETER SYSTEM Filed Jan. 50; 1948 INVENTOR. flaw/er 6. 50m uni/5E.

W AM Patented Dec. 20, 1949 ELECTRIC MICROMETER SYSTEM Henry C. Schildmeier, Indianapolis, Ind.

Application January 30, 1948, Serial No. 5,342

11 Claims. 1

This invention relates to a micrometer of the electric type.

The chief object of the present invention is to magnify a minute dimension departure and translate same into electrical energy, the variation in the electrical energy being readily measurable and readable upon an indicator such as a current meter (ammeter).

The chief feature of the present invention resides in the utilization of flux variation in a simple form of micrometer and measurement of such variation by suitable means, the flux varying structure being directly incorporated in a micrometer which may be of the portable type.

Heretofore in the art of measuring devices there has been provided an electromagnetic field in which an armature is movable and effects current variation which when magnified can be read upon an ammeter. Such micro-measuring devices are exceedingly expensive, usually of large size and not readily portable and above all are quite expensive as well as very delicate.

The present invention eliminates all these objections.

Other objects and features of the invention will be set forth more fully hereinafter.

The full nature of the invention will be understood from the accompanying drawings and the following description and claims.

In the drawings:

Fig. 1 is a top plan View of the micrometer portion of the invention.

Fig. 2 is a side elevation thereof.

Fig. 3 is a wiring diagram.

In Figs. 1 and 2 of the drawings, I indicates a tubular or like guide with extended channel portion H and foot I2. Slidable in said guide is a tubular member [3 mounting handle Id at an exposed end. The other end, slidable in channel ll, mounts C-head with hearing face or anvil [6. This tubular member is cut away at its top portion forming a channel nested, intermediate channel portion ll.

Adjacent the c-head are a pair spaced ears l8 and 19 of para-magnetic material. These ears are connected together as at 20 and suitably secured to the tubular member I3. Ears l8 and IS with screw I9a and nut l8a secure one leg of a U-shaped laminated magnetic core 2! to said tubular member. Disposed about the other leg of said core is the coil 22 with leads 23 and 23a.

slidable in both tubes is the rod 24 which may be tubular if desired. Herein one exposed end of the solid rod is threaded as at 25 to anchor knob decreases 26. The opposite exposed end of said rod is threaded at 21 for an appreciable length. Thereon is threaded nut 28 and hammer head 29, the latter having a threaded socket 30 to take the threaded end 2? of said rod. Nut 28 looks the hammer to the rod in adjusted position. In the event of wear, the hammer may be replaced.

Carried by rod 24 at the portion exposed by tubes l0 and i3 is the para-magnetic base 3| having clips 32 with ends 32a and ears 33 associated with bolts and nut 34. Mounted thereby is the laminated magnetic U-shaped core 35, one arm being associated with the base and the other arm mounting a coil 36 having leads 3! and 37a.

Reference will now be had to Fig. 3.. A pair of supply lines LI and L2 are connected to the leads 23 and 23a of the coil 22. If desired. a potentiometer 38 may be included in this circuit. A direct current milliammeter 39 may be connected through rectifier 40 to the leads 3'! and 31a of coil 36. If desired, a potentiometer 4| may be included in this secondary circuit.

When the two cores 2| and 3-5 are in abutting relation the full flux relationship possible is attained. The potentiometer or potentiometers are adjusted to attain maximum needle deflection or ammeter indication. When the cores are slightly separated, the reluctance of the magnetic circuit increase and current value in the secondary proportionately. Micro-measurable differences in air gap between cores produces comparable large signal indication differences. While these do not, over a wide range of linear unit differences, have corresponding unit differences in signal indications, the fact that decreasing secondary current values indicate increasing linear departures permits this simple device to be utilized for micro-measurement purposes.

For example, if the stock dimension required is 1.250 inches, the several parts of the device are adjusted so that 1.253 inches of distance between anvil l6 and hammer 29 produces approximately maximum needle deflection. Then a guage block of 1.250 inches is applied and the current value adjusted by the potentiometer or potentiometers so that the zero reading of the indicator needle reads unity or ten on the scale if the ammeter is of dual scale type. Then any 0.0001 inch departure from the critical dimension plus or minus in a thousandth of an inch will result in a reading of 1.1 or 0.9 on the unity scale respectively. Since the difference between 1.1 and 1.0 or 1.0 and 1.1 on the scale is provided with five, ten or twenty divisions, the actual linear distance departure from the required standard can be readily and accurately determined. If the maximum tolerance is plus or minus two ten thousandths of an inch, it is readily indicated.

Undersize and oversize articles outside of the micro-tolerances can be readily detected and discarded. Of course, the oversize articles can be reduced and salvaged.

Herein an outside caliper type micrometer is illustrated. --For 'measurment-of holes and cavities an inside type caliper micrometer may be utilized and the undersize rejects reworked arid salvaged.

While the invention has been illustrated'and described in great detail in the drawings and foregoing description, the same =is to -he c'ons'idered as illustrative and not restrictive in character.

The several modifications described hrein as well as others which will readily suggest themselves: to persons skilled in this art, all are considered to'jbe with-in-the broad-scope of theinventio'n, reference being had to the appended claims.

*Theinvention claimedisz 1. -A micro micrometerstructurehaving a pair of linearly separable' ele-ments for measuring, a pairof" confronting coils each rigid with anelement,--a' core-for -each-coil having a pole face, the pair-of pole faces-confronting eachother, the cores -"bei-ng--substantially saturated at the required dimensionpa current supply for one coil, and-a current :measur-ing-device in the circuit of the-other coil,--movement of the indicator of the; device from -a predetermined selected maximum position;indicating variation of the measured distance for the required dimension.

25A micro-micrometer -comprising an elongated membema-second elongated member, a U shaped magnetic -core magnetically insulated from and-carriedby-each member, the core pole faces confrontingeachother, a coil carried -by each coresa current-supply forcne coil, a current; measuring clevice, and --conne ctions between the other-eoiland the --device,- relative movement of themembers being-;indicated- 'on thadevice.

--3. A micrometer as-;definedby-claim 2 wherein--a potentiometer --is inseries with one of the coils.

%.-A- micrometer as defined -by claim 2 wherein the -eurrent supply is of alte'rnating current b'i'ars,"theLnlitermost of the members comprising ahandle and guide, the intermediate and innermost tvio m'embei-s being relatively movable and also longitudinally movable relative to the outermostni'einherfthethree members being incapableof 'axial rotation, a U-shaped magnetic core magnetically insulated from and carried by each of '-the said intermediate and innermost members, .each core having a poleface,thepole'faces of the cores confronting each other aico'il carried by-each core in symmetrical relation,- a current supply for one coil, and an indicator device in seris'wit'h'the other coil, the coils having a priinary secondary circuit relationship.

9. 'A micrometer as"defin'ed"'by -claim"8 wherein each core comprises a pair f 'siibstantially parallel arms and each core is mounted by one arm" thereof. a

1'0. trignereifietefas"defined by claim 9 where in the coils "arse-roamed on the other "arms of thecore's, I v

1-1. "Air'icrorneter as defined by'clairn 's wne'feinthe 'coifes are-tr laininated"'chaiactr, the "cursfip'ply-"is of' alteifnatirig current type, the indicator 'lde' vi'e'c "i er eirecteurrent' type, and arctifier' is'i'n'se 'e's' with said"-device.

HENRY C. SCHILDMEIER.

REFERENGES'CI'TED The -followi-ng references are ot record in the file of this patent:

I'iN'I'I EU STKTE'S PATENTS

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