US1195861A - Edward f - Google Patents

Description

E F. SMITH.

MANUFACTURE AND CONSTRUCTION m mmmmms.

APPLICATION FILED JULY 16x 19;.

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EDWARD F. SMITH, OF CINCINNATI, OHIO, ASSIGNOR TO THE NEIL & SMITH ELECTRIC MANUFACTURE AND CONSTRUCTION OF COMMUTATORS.

Specification of Letters Patent.

Patented Aug. 22, 1916.

Application filed July 16, 1914. Serial No. 851,389.

To all whom. it may concern:

Be it known that I, EDWARD F. SMITH, residing at Cincinnati, Hamilton county, State of Ohio, have invented certain new and useful Improvements in the Manufacture and Construction of Commutators, of which the following is a clear, full, and exact description, attention being called to the drawing which accompanies this application and forms a part thereof.

This invention concerns the construction and manufacture of devices known as commutators and forming adjuncts of certain types of generators and dynamos. They consist of segments assembled side by side and radially disposed around a common center so as to form a. cylindrical body which is adapted to be mounted upon a shaft, each segment being insulated from the other and from said shaft. A so-called brush, another adjunct, is used in connection with these commutators, it being held in yieldingcontact with the outer, cylindrical side thereof and while one of these devices rotates with reference to the other one. It is desirable that this contact be a perfect one and .without the slightest interruption, otherwise sparking results which is very objectionable because destructive to the commutator and to the brushes. Such interruptions result when the surface of the commutator which is in contact with the brushes is not cylindrically true, if insulating material and segments do not wear-away equally, leaving ridges, or if the segments with the insulating material between them are not so firmly held together as to form an absolutely rigid body. Either one of these conditions produces vibrations of the brushes whereby terfiporarily their contact is interrupted, causing the gap to be bridged by the objectionable spark.

The object of my invention is to construct commutators in a manner whereby the various segments are firmly held together so as to form with the insulating material between them a solid mass, homogeneous and integral for all practical purposes and to present a brush-contact surface which wears equally in all its parts and remains therefore cylindrical at all times.

The invention consists of the method of producing commutators in the manner aforesaid and of the commutator itself and constructed in accordance with this method.

In the following specification and claims is found a full description of my invention, its parts, and the manner in which it is practised, all of which is illustrated in the accompanying drawing in which:

Figure 1 shows in perspective view a block of metal to be used in the production of a commutator according to my plan. Fig. 2 shows a commutator blank formed out of this block. Fig. 3- is a vertical cross section on a planeindicated by numerals shown in Fig. 2. Fig. 4 in a sectional view shows an apparatus whereby the aforesaid blank is acted upon in a certain manner. Fig. 5 in a view similar to Fig. 2, shows appearance of the blank after having been acted upon by the apparatus shown in Fig. 4. Fig. 6 also a similar view, shows the blank further advanced in the state of its manufacture. Fig. 7 is an axial section of the completed commutator.

In the drawing, Fig. 1, shows suitable metal preferably'copper which is used in my improved manufacture of commutators and in a preliminary shape which may be the form of a cylindrical block 10. This block, by suitable machine "001 operation, is further shaped so as to have a central bore 11, countersunk recesses 12, 12 in its opposite flat sides and radially arranged cuts 13 which extend in from the peripheral side toward said bore. These cuts are all of practically equal depth and terminate so as to leave an intact annular zone of metal 14 around said bore so that a blank results as shown in Figs. 2 and 3. This blank is now placed within a cylinder 15 and with one of its flat sides upon a base 16 as shown in Fig. 4. Dielectric material 17, in plastic condition, is placed upon the blank within the cylinder and by means of a plunger 18 this material is forced against said blank so as to enter all open parts of the same, particularly cuts 13, the object being to fill these latter completely. Material in excess of that really required is used and cylinder 15 rests loosely upon base 16, so'that the surplus may disgorge from below the lower edge of the cylinder, this latter being lifted by the reaction. This impressing of material may be repeated until all of the cuts 13 and each one of them are thoroughly filled and packed. The blanks are now removed from cylinder 15, surplus material, especially that which fills bore 11 and recesses 12-42, is removed and they are set aside to permit the material to harden. This may be effected byair-drying, if there is sufiicient time; otherwisehthe use of artificial heat will be resorted to. Next the blanks while secured in a suitable holding device are rebored torem ove themetal l twithin I bore 11 from which actionfinally a struc- .and consisting of two complementary mem- 'bers 21 and22,"is finally placed into bore '11 and recesses 12-12. It. is insulated from the commutator by washers 23. "Material 17 in addition to beingdielectric should be also inert and neutral with referenceto the acv tion of acidsor alkalis and so as'not' to he ture results as'shown inF-igsgfi; and 7, and composed of; segments 19, 'allfin'sulated from each other by material'l? whereby they are also held together. A usual bushing, to form a bearing for the commutator susceptible to the action of grease, oil or water, nor aflected by heat. Pulverized as-Q bestos or mica mixed with"a suitable binder are preferable materials. I use pulverized -mica formed into a plastic mass by means of silicatemf soda. Whiting is added to overcome the porosity ofthe micawhich would reduce the densityof the massand render it more or less elastic. This mass by being applied in the manner stated automatically fills cuts 13 completely, no matter whether they are perfect or not, that is ness, they cannot adjust themselves to irre'gularities in the shape of the segments or in the surface of the sides thereof, nor to differences in the size of the spaces'between them. As a result neither the segments nor the material between them are held rigid, spaces result between them, they do not form a compact body, segments may move and possibility of vibration exists. Furthermore, 1n applicants case, the material is of a granular texture, and wears away .even with the tree outer ends of the seg-- ments so that no high spots or ridges re- The apparatus for applying the insulating material may be of a size to admit a number of blanks,- superposed, or side by side, so that a number of them may be acted upon. Byproperly gaging the quantity of the mass, the operation'may consist of one operation of the plunger or-several charges may beappliedt I Having descri asnew: .r 1. The method of manufacturing commutators which consists of producing an integral cylindrical blank of metal which con tains the metal forthe segments and is provided with radially disposed spaces between the metal intended 'for said segments, of

filling these spaces with insulating material and of removing the metal at the inner ends of these filled spacesso as to completely separate the segments from each other;

'2. The method of manufacturing commutators which consists of producing an in,

tegralcylindrical blank of metal which contains the metal for the segments and is provided with radially disposed spaces between the metal intended forsaid segments, of filling these spaces with insulating material and of axially boring out said blank, the

bore being of an extent to reach into the in- 86 ner ends of the filled spaces so as to completely part the segments from each other. In testimony whereof, I'hereunto atfix my signature in the EDWARD F. SMITH.

Witnesses: i

C. s asm, A. JOHNSON.

bed invention, I claim 65 presence of two witnesses.

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