US2040060A - Electrical indicating instrument - Google Patents

Description

May 5, 1936.

l.. H. MIDDLETON 2,040,060

ELECTRICAL INDICATING INSTRUMENT Filed June 22, 1934 lllli l 2161i mum n 6 l I tl INVENTOR LESLIE H. MIDDLETON BY HIS ATTORNEYS Patented May 5, 1936 ELECTRICAL INDICATING INSTRUMENT Leslie H. Middleton, La Crosse, Wis., assignor, by mesne assignments, to Moto Meter Gauge & Equipment Corporation, a corporation of Delaware (1935) Application June zz, 1934, serial No. '131,968

12 Claims.

This invention relates to electric gasoline gauge heads comprising a pointer type galvanometer responsive to a oat controlled rheostat for indicating liquid level, particularly in gasoline tanks of automotive vehicles, such as shown and described in Cheney Patents No. 1,745,603 granted February 4th, 1930, and No. 1,753,402 granted April 8th, 1930, on which the present invention is an improvement.

Objects of this invention are to strengthen the construction of gauge heads of this character, to increase the torque upon the pointer whereby the effect of road shocks and vibration thereon is decreased; to improve the magnetic circuit, and to l5 facilitate adjustment and calibration of the instrument.

Other objects will become apparent as the following description proceeds, with reference to the accompanying drawing, in which Figure 1 is a front elevation of the instrument with the dial removed;

Figure 2 is an inverted plan;

Figure 3 is a rear elevation; and

Figure 4 is an expanded perspective view of 25 the iiux distributing plate.

'I'he frame of the instrument comprises a metal base plate 6 having upwardly and laterally extending wings I and 8 on which the magnet coils 9 and I0 are mounted, and lower arms II and I2 which are bent forwardly and then upwardly to receive and support the dial I5. Between the arms Il and I 2 a loop I6 is bent forwardly and upwardly to support the front bearing of the armature shaft.

A strip of fiber insulation I'I is mounted in back of the frame base plate 6, between lugs I8 bent back therefrom. A metal backing plate I9 has lugs 20 bent forwardly around the insulation strip l'I, and has lateral wings 2| and 22 overlying the base plate wings 'I and 8.

The coil 9 is a constant coil having higher resistance and less magnetic, strength than the variable coil I0. These coils each have an iron core in the form of a spool, which is mounted on a bracket 23 of a box corner type. The stem 24 of the core spool extends through an opening in the upstanding ange 25 of the bracket, and is upset or peened to secure a rigid mounting thereon. The inner disk of the spool is slotted and the metal therebetween bent inwardly to form pole tips 26.

The flux distributing plate 21 shown in Figure 4 is mounted on the plate 6 with its branches overlying the wings 1 and 8 of the frame base plate. The base 28 of the bracket of the constant coil 9 is placed over the flux distributing plate, and a. screw 29 inserted from the back of the instrument passes through registering openings in the wing 2|, the wing 1, the plate 21 and the bracket base 28, rigidly securing the constant coil 9 in position with its core aligned with the armature shaft.

The coil I0 however, is intended to be adjusted and for this reason the holes in the wing 22, the wing 8, and the branch 30 of the flux distributing plate are elongated to form slots 35, and the screw 32 passes through these registering slots into the base 33 of the bracket for the coil I0.

The flux distributing plate has a movable eX- tension, the base 34 of which overlies the branch 30 and underlies the base 33, and the screw 32 passes therethrough also. This extension has an ear 36 caught between the spool of coil I0 and the bracket flange 25, and through which the stem 24 passes, so that the extension 34 is rigid with the base 33.

Another branch of the flux distributing plate has an integral extension 3'I which is turned up toward the outer pole of the constant coil 9. A third branch 38 is turned up at the bottom of 25 the instrument, between the sides of the loop I6, adjacent to the armature.

The armature 40 comprises a double segment of iron rigidly secured to a spindle 4I journaled in a clock bearing carried by a screw 42 which extends through the plate 6 and the flux distributing plate 21. The front end of the armature spindle is journaled in a clock bearing 43 fixed in the loop I6. A pointer 44 and a counterweight 45 therefor are also rigidly secured to the spindle 4 I.

The clock type bearings are long and rugged, and avoid difliculties of the old conical pointed pivots. The parts are held in constant and permanent alignment, irrespective of magnetic and mechanical forces acting upon the spindle and bearings.

A loose fly-wheel 46 or inertia dampener, is mounted on the spindle 4I between two collars 41 slightly spaced therefrom. The center hole in the fly-Wheel 46 is slightly larger than the spindle, so that frictional engagement with the shaft and collars is the only connectionto the spindle.

As the pointer must overcome the natural inertia of the fly-wheel, which opposes any movement thereof, the same is dampened to' avoid vibration thereof due to road shocks and jarring.

The lower arms II and I2 of the base plate 6, which form posts to support the dial plate I5, are entirely separate and distinct from the gauge movement itself, thereby avoiding any possibility 55 'loV of dial movement being transmitted to the gauge movement, and preventing sticking and binding. An upper contact stud 48 'passes through the top oi' the insulating strip I1, and a lower or central contact stud 49 passes through the frame base plate 9 and the strip l1, the head oi the stud being insulated from the plate 6. Contact tabs 56 are mounted under the heads of each of these studs, and in electrical contact therewith.

The constant coil 9 has an end grounded to the frame, and the other end connected by one of the tabs 50 to the central contact stud 49. The variable coil I6 is connected to the tank fitting rheostat one end of which is grounded.

As the current is gradually increased through the variable coil I6 due tonlling the gas tank and cutting out resistance in the tank rheostat,

the iield strength trom the tips 26 of the variable` coil I9 is increased, and this tends to move the amature from a position opposite the constant coil 9 to a position opposite the variable coil I0.

The pole tips 26 are of advantage in that they are in close proximity to the armature 40, which serves to concentrate the flux from each coil at these tips 26. When the tank fitting oat rheostat is in the "empty position, there is no current ilowing through the variable coil I0 and the current owing through the constant coil 9 generates a ideld concentrated at the tips 26, tending to hold the armature in zero position.

The variable coil l0 has corresponding pole tips which concentrate the iield thereof in the same manner. The strength of the eld generated by this variable coil I0 is dependent upon the current therethrough, in'turn dependent upon the rheostat as controlled by the float in the tank.

These pole tips 26 therefore, serve to concentrate these various field forces in the path of the armature. Without these tips 26, the poles would have to be very close to the armature, to concentrate the flux for the torque necessary to stabilize the pointer under road shocks and vibrations.

The ilux distributing plate forms a complete iron circuit for the magnetic ilux, and incloses both of the coils and the armature. 'I'he branch terminating in the bendable tip or integral extension 91, is associated with the outer pole of the constant coil 9.

'I'he movable extension 96 which is riveted on to the outer pole of the variable coil l0, having its base 94 movable with respect to the slot 99 in the iiux plate proper, results in a sliding connection between the iron core of the variable coil I0, and the flux distributing plate, but a considerable leakage passes between the core of the constant coil 9 and this plate, at the bendable tip 91.

'I'he central arcuate branch 98 is associated with the amature 46, and has its tip curved to approximate the path ot this armature, so that there is no change in the air gap between the armature and this ux plate, and no change in the neld strength,.at any point in the armature path.

In assembling the instrument, the constant coil 9 is fixed solid in a predetermined definite po- -sition `on the base plate 6, as by means ot a jig.

The variablecoil Iissetinanarbitrary position during assembly.

The gauge is calibrated on zero by bending the tip 91 oi' the ux distributing plate upwards or sideways through a range oi' about one sixteenth of aninchwithrespecttotheouterendotthe iron core spool of the constant coil 9. Thus4 the zero calibration is eected by bending back and forth the iron circuit connecting it to the main flux circuit.

'I'he screw holding the variable coil in position passes through a slot in the base plate and iiux distributing plate, so that this coil is adjustable for rotation about this screw and also inwardly and outwardly, so as to obtain the desired overall range on the instrument in connectionwith the adjustment oi' the constant coil above referred to. 'I'he pointer position when all resistance is cut out from the tank rheostat is adjusted particularly by the position of the variable coil.

The scale range adjustment is made by loosening the screw 92 and moving it along the slots 35, thus moving the var-lame cou lo back and forth from the armature to vary the strength of the iiux; and also by swiveling about the s crew 92 as a pivot, to vary the direction of the ux, after the lateral adjustment has been obtained.

The full position oi! the pointer and the scale characteristics are adjusted by bending the center branch 99 of the iiux distributing plate toward or away from the amature, to strengthen or weaken the `iiux. At the same time, bending the corners oi' this branch 98 in or out permits a slight ilux directional calibration means for correcting scale errors.

The constant coil 9 may be swung about the ymounting screw 29 as a pivot, to adjust the magnetic iield in relation to the ileld of the variable coil I6, to enable the empty, $41, V2, full positions of the pointer to be calibrated at the desired points on the scale.

While it is essential to move the variable coil I 6 to calibrate the gauge, the vconstant coil need not be moved.

The double pole tips in combination with one swiveling adjustable coil and one coil both swiveling and laterally adjustable enable four pole tips to be variable in position with respect to the armature and the two pairs are also variable with respect to each other. Thus these four ilux paths can be adjusted to give any desired scale calibration.

It should be noted that in addition to the ilux strength adjustment of the distance of the coil from the armature, a flux directional distribution adjustment is provided, by the pivotal movement of either of the coils, and by the corner bending of the flux distributing plate tips 91 and 99. 'I'he structure as here described enables the manufacture of a neat, positive, and accurate gas gauge head, which quickly and positively follows any change in the resistance of the tank iltting rheostat, and by the concentration of ileld strength has ample power to cause the pointer to take a true reading position without lag, and has suilicient power to overcome pivot friction ordinarily met with in a gauge of this type. Accurate readings are thus obtained both with an ascending or descending pointer.

What I claim is: c

1. In an electrical instrument, an amature, a frame, a coil having a constant ileld excitation and a coil having a variable eld excitation, said coils being located on said frame at an angle to each other, an inflexible mounting for said coil having the constant eld excitation, and adjustable means for moving said coil having the variable ileld excitation axially toward and away from said armature, and also in a plane perpendicular to the axis of said amature.

2. In an electrical instrument comprising a pointer type galvanometer responsive to a. iloat controlled rheostat for indicating gasoline tank level of automotive vehicles, the combination of a frame, a coil of constant excitation and a coil of variable excitation located on said frame at an angle to each other, means for maintaining said coil of constant excitation in xed position on said frame, means for calibrating the gauge on zero without moving said coil of constant excitation, and adjustable means for moving said coil of variable excitation to alter said angle and thereby adjust the scale range of said gauge.

3. In an electrical instrument, a frame, a coil adapted to produce a constant i'leld of force and a coil adapted to produce a variable fieldof force, said coils being located on said frame at an angle to each other, said coil adapted to produce a variable eld of force having a slidable pivotal mounting on said frame.

4. In an electrical instrument, a frame, a. coil having means for exciting its winding to produce a constant eld, and a coil having means for exciting its winding to produce a variable iield, located on said frame at an angle to each other, a ux distributing plate having portions adjacent both of said coils, and means for adjusting the area of said plate.

5. In an electrical instrument, an armature, a frame, a coil having means for exciting its winding to produce a constant field, and a. coil having means for exciting its winding to produce a variable field, located on said frame at an angle to each other, a ilux distributing plate having portions adjacent both of said coils, adjustable means for moving said variable coil with respect to said armature, and means for altering the relation of the adjacent portion of said flux distributing plate to said constant coil.

6. In an electrical instrument, a frame, an armature, a coil having means for exciting its winding to produce a constant iield, and a coil having means for exciting its Winding to produce a variable eld, located on said vframe at an angle to each other, a ilux distributing plate having portions respectively associated with each of said coils and said armature, and means for respectively adjusting the relation of said portions to said constant coil and armature, and

means for adjustably mounting said variable coil on said frame for movement with respect to said amature.

7. In an electrical instrument, an armature, a frame, a coil having means for exciting its Winding to produce a constant field, and a coil having means for exciting its Winding to produce a variable field, located on said frame at an angle to each other, a ilux distributing plate associated with said coils and armature, and adjustable meansfor moving one of said coils with the associated portion of said plate relative to said armature and to the remainder of said plate.

8. In an electrical instrument, a frame, an armature, a coil of constant excitation and a coil of variable excitation located on said frame at an angle to each other, one of said coils having a pole tip inclined toward said armature in the plane thereof.

9. In an electrical instrument, a frame, an armature, a coil of constant excitation and a coil of variable excitation located on said frame at an angle to each other, one of said coils having a spool core, portions of said core being bent in- Wardly in the plane of said armature, and means for adjusting the position of said coil for altering the flux.

l0. In an electrical instrument, a frame, an armature, a coil of constant excitation and a coil of variable excitation located on said frame at an angle to each other, one of said coils having a spool core, portions of said core being bent inwardly in the plane of said armature to form pole tips, a iiux distributing plate between said coils and frame, adjustable means for moving said variable coil thereon with respect to said armature, said flux distributing plate having bendable branches respectively associated with said constant coil and said armature.

1l. In an electrical instrument, a pair of coils mounted at an angle to eachother, one of said coils having a bent pole tip for concentrating the ilux thereof.

12. In an electrical instrument, an armature and a coil having a spool core, a portion of the flange of said spool being bendable in the plane of the armature for altering the ilux.

LESLE H. MIDDLETON.

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