US422339A - Electric-motor car - Google Patents

Description

(No Model.)

I. H. PARNHAM.

ELECTRIC MOTOR GAR.

PatentQdFeb-25Q189o.

N. Vriens, mxo-Mmmm?. wmingm. uc.

passenger sitting over the motor.-

UNITED STATES PATE- NT OFFICE.

ISAIAI-l Il. FARNHAM, OF MALDEN, ASSIGNOR OF TWOJIHIRDS TO GEO.

WILLIS PIERCE, OF BOSTON, AND ALBERT P. SAIVYER, OF NEVVBURY- PORT, MASSACHUSETTS.

ELECTRIC-MOTOR CAR.

SPECIFICATION forming part of Letters Patent No. 422,339, dated February 25, 1890.

i Application filed April 1889. Serial No. 306,113. (No model.)

To all whom t may con/cern.'

Be it known that I, ISAIAH H. FARNHAM, of Malden, in the county of Middlesex and State of Massachusetts, have invented certain new and useful Improvements in Electric-Motor Cars, of which the following is a specification.

This invention has for its object the protection of watches carried by passengers on cars which are impelled by electric motors.

It is well known that in electric-ear systems now in use each car has one or more electric motors-f-usually two-located below the floor of the car and Within a short distance-say thirty-six to forty inches-from the location of a watch on the person of a The balance and hair-spring of the watch are therefore brought into a strong magnetic eld, and when the hair-spring is made of steel and the balance wholly or in part of steel, as in the great majority of watches now in use, said parts become magnetized to such extent as i to seriously affect the time-keeping properties of the watches thus exposed. Much complaint has been caused among thepatrons of electric-motor cars by this disturbance of time-pieces, and many are obliged to go to the expense of having non-magnetic balances and hair-springs applied to their watches.

My invention has for its object to obviate this objection by sod detlecting the lines of force radiating from the electric motor or motors and from the conductors connecting said motors with overhead wires that watches carried by passengers within the car will be screened and protected from such lines of force. To this end my invention consists in the combination, with a car and an electric motor,

of a shield of magnetic metal interposed between the motor and the portions of the interior of the car which would otherwise be within the magnetic field of said motor, said shield deiiecting the lines of force from the motor toward said portions of the interior of the car, and preventing the described injurious action on watches located therein, as I will now proceed to describe.

The accompanying drawing, forming a part of thisspeciiication, represents a side elevation and partial longitudinal section of a car provided with my improvement.

In the drawing, a represents the body of a street-car, and b b represent two electric motors of any suit-able construction located unl der the car and suitably geared to the axles of the wheels thereof. The type of motor here shown is known as the Sprague motor;7 but it is obvious that my improvement may be employed with any other motor which is capable of being used for this purpose.

In carrying out my invention I interppse between the motor and the interior of the car a shield s, composed of a suitable magnetic metal, as wrought-iron. Said shield may be made of one or more sheets or layers of metal attached to any suitable part of the car. I have here shown the shield as composed of two sheets, one attached to the bottom of the car and the other between the vtop and bottom layers of the floor of the car.

The thickness of the sheet or sheets of iron and the area of extension of the same length- Wise and crosswise of the ear may depend on the constructionA and location of the motor. I recommend a sheet of about one-sixteenth of an inch in thickness, but do not, of course, limit myself in this particular.

I consider it advisable to give the shield sufficient area to interpose it between the motor or motors and all parts of the interior of the car, which, wit-hout said shield, would be within the magnetic iield or fields of the motor or motors. In some caseswhen two motors are employed an independent shield may be employed for each motor.

In cars in which the motor is placed above the floor of the car the shield should be in the form of a box or casing arranged to deflect or prevent the radiation of the lines of force extending laterally or horizontally, as well as upwardly, from the motor, or in any 'other'suitable way to constitute a barrier to the lines of force between the motor and any part of the car where a passengers watch may be located.

I include under the term motor the conductors t, which connect the motor proper with overhead wires through trolleys, and in cars which are thus connected the said con- IOO duetors t, or those portions thereof which are within or in close proximity to the interior of the car,sl1onld have shields s of magnetic metal. Said shields may be tubes of sheetiron, or sheet-iron tapes wound spirally about the conductors, or of any other suitable forni and construction. I have shown a portion of but one of said conductors t in the drawing, and a shield s of tubular forin surroundingr the same, said shield being extended down to the upper plate s, above referred to.

I claiml. In a ear or other vehicle, the combination of an electric motor applied thereto, conductors extending from said motor upwardly through the body of the car for connecting Said niotor with the generator-circuit, a fiat shield or shields of magnetic metal completely interposed between the passenger portion or portions of the car and said motor,

and a tubular shield or shieldsinterposed between the passenger portion of the car and said conductors, as set forth.

2. In a car or other vehicle, the combination of an electric motor applied thereto loelow the car, with one or more sheets or plates of magnetic metal interposed between the electric motor and the carloor, all substantially as shown, and for the purpose described.

In testimony whereof I have signed my name to this specification, in the presence ot' two subscribing witnesses, this 30th day of March, A. D. 1889.

ISAIAH H. FARNHAM.

Titnessesz GEo. WILLIS PIERCE, A. D. IIARRIsoN.

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