US1072647A - Dynamo-electric machine. - Google Patents

Description

A. A. PIPER.

DYNAMO ELECTRIC MACHINE.

APPLICATION rum) OCT- 14, 1908.

' 1,072,647, Patented Sept. 9,1913.

2 sums- 11231: 1.

Z'&M; l v I COLUMB A PLANOORAPH 80 W UNITED STATES PATENT OFFICE.

ALVIN A. PIFER, 0F CLEVELAND, OHIO, ASSIGNOR TO CLEVELAND ARMA'IURE WORKS, 0F CLEVELAND, OHIO, A PARTNERSHIP COMPOSED OF ALVIN A. PIFER AND JAMES L. MAULDIN.

DYNAMO-ELECTRIC MACHINE.

To all whom it may concern:

Be it known that I, ALVIN A. PIFER, a citizen of the United States, residing at Cleve land, in the county of Cuyahoga and State of Ohio, have invented a certain new and useful Improvement in Dynamo- Electric Machines, of which the following is a full, clear, and exact description.

The present invention is directed to an improvement in dynamo electric machines and especially concerns a form of variable speed motor of the type invented by myself and C. E. F. Ahlm forming the subject of Patent No. 900,420, October 6th, 1908, variable speed motor. This type of motor embodies pole pieces for the several field magnets, the pole piece for each magnet being divided transversely,that is to say, parallel with the axis of the armature, the two sec tions of the pole piece being movable toward and from each other to vary the strength of the magnetic field and consequently the rate of the armature rotation.

I have discovered that by the improvement to be described below, the ratio of variation may be considerably increased without complicating the structure or impairing the operation of the mechanism.

It has been my object to attain these results without departing from the essential principles of the machine disclosed in said patent, and it will be seen that I have attained this object and other desirable advantages by that embodiment of my invention described in the following specification with reference to the accompanying draw ings, in which;

Figure 1 is a side elevation of a variable speed motor constructed in accordance with my invention, the operating rings being broken away in part and the ole shoe sections being in their closed position. Fig. 2 is a side elevation, with the operating rings and double screw by which they are operated removed. Fig. 3 is an enlarged section through the motor, with the armature removed, showing the structure of the parts. Fig. 4 is an enlarged detail showing the connection of the operating rings to the operating screw.

The type of machine herein shown is based upon the principle of having pole shoes for the field magnets made in sections movable toward and from each other for the purpose of increasing or decreasing the number of Specification of Letters Patent.

Application filed October 14, 1908.

Patented Sept. 9,1913.

Serial No. 457,656.

lines of force passing through the armature and thereby varying the speed of the latter.

. at the same time they are moved toward and from each other. The increase and decrease in air gap between the armature and the pole shoe sections occasioned by this movement rapidly decreases or increases the number of lines of force passing into the armature.

In the design of machine which I have here shown I provide the inner end of the coresA of the field magnets with projecting flanges A having slideways thereon which support and along which slide the sections B, B of the pole shoe placed between each core and the armature C. It is not practical to move the pole shoe sections if they come in actual contact with the core, and consequently I space the said sections slightly apart from the end of the core and use strips of some suitable non-magnetic material, such as brass for engaging the slideways of the pole. These brass strips B are secured to the pole shoe sections and suitably shaped to engage the said slideways and slide freely thereon. It will be seen that these slideways are each parallel with the tangent to the armature at the point out by the extended axis of the core, andtherefore any movement of the pole shoe sections along said ways toward orfrom each other will cause a corresponding travel toward or from the surface of the armature and thus rapidly increase or diminish the resistance given by the air gap between the pole shoe and the armature and increasing or diminishing correspondingly the number of lines of force s unted away from the armature.

The means by which the several sections are caused to travel simultaneously in their proper direction comprises a pair of rings 1), D concentric with the armature on each end of the motor. The set of rings at one end receive their motion directly from an operating shaft, while the set at the other end serve as equalizers. Considering the rings on the end connected with the operating shaft, it will be seen that one ring, namely, the outer D, has a number of pins D projecting therefrom into vertical slots of the left hand member of each pair of the sectional pole shoes, mine the inner ring has a number of-pins D projecting into vertical slots of the right hand members of the sectional pole shoes.

It will be obvious that a movement of the inner ring' in one direction and a movement of the outer ring in the opposite direction will cause a corresponding movement of the same extent for each section of all of the pole shoes. I prefer to attain this movement by means of a shaft D mounted on the frame of the machine and having two reversed threads D, D at the end thereof, one of said threads D engaging a swiveled nut D fixed to the inner ring and the other thread D having a pitch the reverse of the first thread engaging a swiveled nut D on the outer ring. The reason'fo-r swiveling these'nuts is to avoid any strain due to the movement of the nuts in a circular direction of the armature when the sections are moved away from each other.

It will be seen that by means of the construction described I have made it possible to move the pole shoe sections away from the face of the armature at the same time they are moved away from each other and thus attain the object sought, of increas ing the ratio of variation possible within that radius described;

Having thus described claim:

7 1. In combination in a dynamo electric machine having an armature and a plurality of sets of field poles, a regulator comprisinga pair of pole shoe sections at the inner endot each pole, each of the poles having guideways which support the shoes independently or the shoes on, the other.

my invention, I

poles, and permit movement of the shoes toward or away from each other and at the same time toward or from the armature and means operatively connected to the shoes for simultaneously shitting all the shoes.

2. In combination in a dynamo electric machine, an armature, a field member having a plurality of poles a pair of pole shoe sections supported by each pole and having a sliding connection therewith for movement toward and away from each other along the line parallel with the tangent to the armature at the point out by the ex tended axis of the core, and means for simultaneously shifting the pole shoe sections comprising one shifting means having operative connections with alternating sections, and another shitting means having operative connections with the remaining alternating sections.

3. In a dynamo electric machine, an armature a field member having a plurality of inwardly projecting poles, each supporting at its inner end a pair otpole shoe sections havingsliding connections with the pole so that they may be moved toward or away from each other along a line parallel to the line tangent to the armature at the intersection of the armature and 'pole aids, and means for shifting the pole shoe sections of the different poles toward oraway from each other comprising a pair of shifter members each loosely connected with alternating sections.

4; In a dynamo electric machine, an armature; a field member having a plurality of inwardly projecting poles each supporting at its inner end a pair of pole shoe sections,

said pole shoe sections having sliding con nections with the pole on opposite sides of therlatter so that they may be moved toward and away from each other on a line parallel with a line tangent to the armature at the intersection of the armature and pole aXis, and means for simultaneously shifting the pole shoe sections of the different 'poles toward or away from each other comprising a pair of rings, each loosely connected with alternating sections.

In testimony whereof, I hereunto afliX my signature in the presence of two witnesses.

ALVIN A. PIFER.

Witnesses: i

H. R. SULLIVAN,- J. M. \VooDwAnD.

Copies or this patent may be obtained for five cents each, by addressing the Gorn'missioner of Iiatents. Washington, I). C.

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