US1441407A - Electric governing device - Google Patents

Description

Jan. 9, 1923.

W. W. DEAN.

ELECTRIC GovERNrN vlcE. FILED MAY 16. 19,

f'l' N INVENTOR W. W. DEAN.

BY @mM/dw ATTORNE Patented Jan. 9, 1923.

UNITED STATES PATENT OFFICE.

WILLIAM W. DEAN, OI' WILMETTE, ILLINOIS, AssIGNOR 'ro EFFICIENCY ELECTRIC CORPORATION, OINEW YORK, N. Y., A CORPORATION or NEW YORK.

ELECTRIC GOVERNING DEVICE.

Application led May 16,

To all whom t may concern -Be it known that I, WILLIAM W. DEAN, a citizen of the United States, residing at Wilmette, in the 'county of Cook and State of Illinois, have invented certain new and useful Improvements in Electric Governing Devices; and I do hereby declare the following to be a full, clear, concise, and exact description of the'invention, such as Will enable those skilled in the art to which it 'appertains to make and use the same.

i My invention relates tov electric governing devices, and moreparticularly to such governing devices as may be used in con-L nection With motors required to be operated at a constant speed as, for instance, phonograph motors and the like, although I may employ the device of my invention wherever such a device finds a use.

It has 4been previously proposed to control the speed of a motor, such as an electric motor, for driving the turn-table of a phonograph, by centrlfugally operated electric contacts, the same controlling electric circuits adapted under the control of thesey centrifugally operated contacts to retard the speed of the motor, so that the motor cannot exceed a given predetermined speed which is substantially that speed required to actuate the centrifugally Operated contacts.

Many other forms of centrifugally operated contacts have been proposed for this purpose, but all of these I find have been faulty in Operation in one way or another;

for instance, it has previously been proposed to place a steel reed spring mounted rigidly at'one end to a collar carried by the motor shaft and having the other end weighted, the reed extending' substantially parallel with the motor shaft. Also secured to the revolving collar carried by the motor shaft, was a rigid contact carrying member, a rigid contactbeing supported by the said member to co-operate with a second electrical contact secured by the flexible reed at a point betweenthe endsof the reed.

This device while'being a great improvement on prior constructions, still was faulty because the reed would vibrate at a rate depending upon its resiliency, its carried Weight, and the mechanical effect of the contacts, in addition to the electrical effect of the contacts in governing the motor speed. Also the vibrations of the reed were periodic, since the reed structure possessed a consid- 1919. Serial No. 297,624.

erable amount of'inertia and there would be a considerable over throw because of the Inertia of the carried Weight. Other difficult1e s arose, because it was difficult to maintain the contacts in a given condition of ad- Justment, and it was difficult to arrange the contacts so that they could be readily ad- ]usted without stopping the motor.

Varlous schemes were proposed to avoid stoppmg the motor but they all involved greater complexity in `the vmechanical construction, and incidentally introduced other troubles not had in the simpler proposed arrangement. v C

.It has been also proposed to operate a Weighted reed carrying an axially disposed contact, the said reed being rigidly secured at its two ends on each side of the axis of rotation, and the reed being weighted on each side of the axially disposed Contact and between the said contact and the fixed ends 'of the reed.

This structure also has inherent defects, due to the fact that at different temperatures the reed expands and its ends being rigidly secured, its mid portion moves from its normal position of adjustment carrying its electrical contact, thus altering the adjustment of the contacts; this governor also being` defective in that the over-throw tendency, due to the inertia of the carried weights was still present and successive pulses of speed variations were produced as in the prior electrical governing contactconstructions;

In the device of my`V present invention I eliminate these defects by using a simple stripped reed, unweighted, secured at only one end, and having its contacts axially'disposed. I mount this reed on the rim of a rotatable collar carried by the shaft, the reed being secured at one end in such a way that when at rest, it is disposed at a considerable angle-to the plane of rotation and in operation, due to the centrifugal effect of rotation, the reed attempts to place itself inY this plane.

The effect of this tendency is that due to to the contrifugal force, the free end of the reed is thrown outwardly and toward the same plane in which the fixed end of the reed rotates, theJ intermediate or contact carrying portion of the reed being deflected to an extent proportional tojthe deflections of the free end.

In this connection as above stated, I preferably place the electrical contact secured by the reed in a direct line with the true axis of rotation with the shaft. Opposed to and co-operating with this contact is a fixed contact rigidly 'and adjustably secured independent of the motor shaft, and the reed contact due to the above described eHect of centrifugal force when a predetermined speed is attained, makes contact with the fixed contact, closing the electrical circuit which when closed controls the motor speed in any desired way.

By referring to the drawings comprising a portion of this specification, a better understanding of my invention may be had.

Fig. l, shows an embodiment of my invention applied to an electric motor shaft and included in a controlling electric circuit for the electric motor, whereby the speed of the motor is regulated. The centrifugally operated contacts of Fig. l are of the normally open type,` being closed at a predetermined speed.

Fig. 1B, shows the same type of centrifugally operated contacts, wherein the contacts are of the normally closed type, being opened at the given predetermined speed.

Fig. 1A, shows an end view of the flywheel and carried reed spring of either type.

Referring now to Fig. l, at M, I show an electric motor driving a turn-table TN of a phonograph, through a worin and gear power transmision mechanism lll-G. A spring S, is shown pressing in one direction the motor shaft SS, which is understood to have a thrust bearing located at the end of the motor TB to the left thereof. the spring S and the said thrust bearing being provided for the purpose of maintaining a constant longitudinal shaftadjustment. Carried by the other end of the shaft SS and rigidly secured thereto b a set screw J, is a flywheel FW, herein i lustrated as a cup-shaped member having an annular rim as AR. Rigidly secured to one side of this rim by screws SC, is a flat reed spring RS, which by virture of the concavity and the beveled edge cup-shaped flywheel FW to which it is secured, extends at an angle to the plane of the outer edge of the cupped flywheel.

The llat spring reed member RS,"-illus trated in allof the figures, carries at an intermediate point an electrical contact EC, the spring being of such a length that a considerable portion thereof extends beyond the said contact EC on lthe opposite side of the shaft frpm its fixed end.

I find that as the shaft speed increases, the reed spring RS vtends to be thrown into the same planev as the planev of rotation of the flywheel, and this occurs without any periodic beats as is the case with a weighted reed spring, and that when contact is made with the rigid contact by the reed carried contact EC, that the same is accomplished without there being any appreciable over throw bythe end of the unweighted reed tongue RS, as is the case in the prior constructions, where the same is weighted, and therefore by employing a very quick acting speed retarding means under the control of these electrical contacts, the speed is immediately retarded and thecontacts can be immediately restored. Thus referring to the system of Fig. l, when the predetermined speed is reached and the controlling contacts closed, a circuit is completed for the relay U, and current from the power circuit line wires 3 and 4, is conducted through the said relay.

This relay being energized, will attract its armature, breaking its normally made contacts, and inserting a resistance in the circuit of the motor, which resistance is normally shunted by the said relay contacts. In this way the motor speed is immediately reduced and the centrifugally operated electrical contacts are again opened on account of the flat. reed member RS, tending to unflex: this because of the retractile power of the spring which begins to overcome the centrifugal force produced by the revolving flywheel upon the said reed member.

l vfind that with the reed spring of my invention when the motor is operated to turn the phonograph turn-table TN, that the deflection of the reed spring is almost constant. the variation being too minute and rapidk to be noticed either by the eye or by their eli'ect upon the motor speed, the motor 100 speed being held almost. absolutely constant there being no hunting action by the motor in its effort to maintain an average predetermined speed, the increments of speed corrections heilig supplied by the governing 105 contacts at such rapidly succeeding intervals, that there is a-continuous flow of speed correcting impulses supplied by these contacts, and whereas in the system of Fig. 1, illustrated, the relay member will produce a 110 musical .note so rapid is the armature required to vibrate, in unison with the governing contacts; also by listening to this musical note one is struck by the absence of beats as are very prominent with the 115 weighted contact reeds of the prior art.

I am aware that the device of my invention may be used in systems departing quite widely from the system illustrated in Fig.

l, and I am aware that other departures 120 may be made from the embodiment of my invention herein illustrated and described, but what I claim as my invention is defined in the following claims l. In combination with an electric motor, 125 of a rotatable sha-ft, a set of electric circuit controlling contactors, a reed, said reed having a point of support and a free end, said reed being so constructed that the weight of a truncated section between two planes at 30 right angles to thelongitudinal axis lof the reed weighs not more than any other truncated section'between two other planes at right angles to the longitudinal axis of the reed`,-said last named planes beingvat the same distance from each other as the first two planes are to each other, said last named planes being taken nearer the point of reed support, said reed at its point of support being secured tp the said shaft, the vfree end of the said reed being adapted to be moved axially with respect to the said shaft when` the said shaft is rotated, said reed carrying one of the contactors of the said contact set.

Q. In combination with a rotatable shaft, a setV of electric contacts/a reed carrying one of the said contacts, said reed having a free end and 'a point of support, said point of support` being carried by the said shaft, said reed being responsive to a predetermined motor speed to operate the said contacts, said reed when the motor is lat rest havinga substantial portion of its free end extending at an angle to the plane of rotation of the said shaft and being adapted to place the said portion more nearly in the said plane when the motor is operated to rotate the said shaft; s aid reed being so constructed that the weight of anytruncated section between two planes at right angles to the longitudinal axis of the reed weighs not more than any other similar truncated section taken near the point of suspension.

3. In combination, an electric motor, a motor shaft, a reed, said reed having a free end and a point of support, a reed supporting means carried by the shaft and having a portion located rradially thereof, said point of support being secured" to said radially 1o`` cated portion at apoint to oneside of 'the shaft, the free end of the said reed extending over the end of the'said sha-ft and to the other side thereof, said free end having a sub- J stantial portion disposed out of the plane of other similar truncated section taken nearerV the point of support. y

4.. In combination, an electric motor, a motor shaft, a reed, said reed having a free end and a point of support, a reed supportingmeans carried by the shaft and having a portion located radially therof, said point of support being secured to said radially located portion at a point to one side of the shaft,

the free end of the said reed extending over i' the end ofthe said shaft and to the other side thereof, said free end having a substantial portion disposed out of the plane of y Vthe shaft, the free end ofthe said reed extending over the end of the said shaft and to the other side thereof, said free end having a, substantial portion disposed out of the plane of rotation of the said point of support, an electric-contact carried by the said reed in line with the axis of rotation of the said shaft, said reed comprising a flexible member whose cross section taken at right angles to the longitudinal axis of the reed is not more than the cross section of any parallel plane nearer its point of support.

6. In combination, an electric motor, a motor shaft, a reed carried by the said shaft, said reed having a free end and a point of support, areed and shaft connecting means,

said point of support being secured toNsaid means at a point to one side of the line of the shaft axis, the free end of the said reed extending over the end of the said shaft and to the other` side thereof, said free end having asubstantial portion disposed ut of the plane of rotation ofthe said point of support, an electric contactcarried by the said reed in line withf/the axis of rotation of the said shaft, said/ reed comprising a flexible flattened member Whose transverse 'crosssections are Anot less nearer the point of support than those relatively more distant therefrom.

In witness whereofI hereunto subscribe my name.

WILLIAM w. DEAN.

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