US2102347A - Commutator brush - Google Patents

Description

Dec. 14, 1937. c ARNOLD 2,102,347

COMMUTATOR BRUSH Filed June 29, 1936 Ema/whom Jwvzzs 67/42/1040 3% fiQwmz w.

ratented Dec. 14, 1937 COMMUTATOR BRUSH James 0. Arnold, Los Angelea, Calm, assignmto Lane-Wells Company, Los

Angeles, Calif., a

corporation of Delaware Application June 29, 1936, Serial No. 87,965 8 Claims. (Cl. 171-323) This invention relates to commutator brushes. Commutators are often utilized in conjunction with recording instruments and apparatus designed to measure the electrical characteristics 6 of two or more circuits either to obtain an average thereof or to compare. Also, commutators are incorporated in instruments which measure a single circuit under different conditions as when the polarity is reversed or the phase relation is changed. For example, in the electrical prospecting of well bores by certain methods, two circuits are utilized and the measuring instrument is interposed alternatingly therein.

It is often mandatory in conjunction with commutators so employed to insure that the making and breaking of contacts with the circuits associated therewith are exactly simultaneous, particularly where the power in such circuits is low, in order that there be no fluctuation in the measuring device occasioned by such making or breaking of contact which would interfere with the variable being measured.

Accordingly, the objects of this invention are:

First, to provide a commutator brush comprising dual brush elements which delineate its axially extending margins.

Second, to provide a commutator brush wherein such brush elements may be independently adjusted arcuately to change the eflective width 0 of said brush as well as the position as a whole of the commutator brush.

Third, to provide a commutator brush which, when several are positioned about a commutator, is particularly arranged to permit adjustment of 35 each commutator brush with respect to the others so that the making and breaking of the several commutator brushes may occur simultaneously.

Fourth, to provide a commutator brush which incorporates a novelly constructed brush element 40 having a thin line contact only with the commutator so.that the point of contact is accurately defined.

Fifth, to provide, on the whole, a commutator brush of this class which is simple of operation 45 and adjustment, easily installed and incorporated with conventional commutator arrangements, and which does not readily deteriorate or get out of order.

With the above and other objects in view as 50 may appear hereinafter, reference is made to the accompanying drawing, in which:

Fig. 1 is an elevational view of a commutator and drive therefor incorporating my commutator brush.

65 Fig. 2 is an enlarged transverse sectional view through 2--2 of Fig. 1 showing several of the commutator brush units in engagement with the commutator.

Fig. 3 is an end elevational view of one of the commutator units taken through 3-4 of Fig. 2. 5 Fig. 4 is a sectional view thereof taken through 4-4 of Fig. 2.

In the accompanying drawing, my commutator brush is shown in conjunction with a motor driven commutator such as employed in con- 10 junction with well bore surveying apparatus. A base I is provided, at one end of which is mounted a motor 2 which turns a drive shaft 3 extending through bearings provided in upstanding bracket plates 4 between which is mounted a commutator l5 5. The commutator 5 is shown as comprising substantially semicircular conductor segments I electrically connected to conductor rings 1 and separated by suitable insulation 8. The bracket plates 4 are connected by four brush supporting 0 bars 9 which parallel the commutator and are positioned equally around the commutator.

The bars 9 serve to support a plurality of commutator brush units ll. Each brush unit which rides upon the conductor segments 8 includes an 25 eccentric bushing i2 of insulating material which is mounted upon one of the bars 8 and is adapted to be secured thereto by a set screw II. The eccentric bushing is provided with Journaled bosses l4 at each end upon which ride a pair of side plates l5 forming a part of a brush arm Hi. The side plate extends either over or under the commutator, depending upon the bar with which it is associated. These plates are connected by a cross piece I! near their extended ends. Each cross piece receives a brush element ll. Each brush element is in the form of a flat strip of conducting material forming a supported end l9 which lies flat against the corresponding 40 cross piece and contact fingers 20 formed by making parallel slits inwardly from the extended end, as shown best in Fig. 3.

The contact fingers may extend directly from the supported end at an angle therewith or an oflset 2| may be interposed, as shown best in Fig. 2; the purpose being to position the contact fingers in the right relation with the commutator. Each brush element is held in place by a screw 22. One screw sufiices by reason of the fact that the side plates l5 project past the cross piece 20 and restrain the brush element against turning.

The commutator brush units H are arranged in pairs with the extended ends of the members of each pair disposed contiguously to each other. In order to electrically connect the members of each pair of commutator brush units and to urge their brush elements against the commutator, the cross pieces it are provided with outwardly extending pins 23, and the pins of each pair are connected by springs 22d.

in addition to the commutator brush units it which ride on the segmental portions of the commutator, othe" brush units 25 provided which ride re conductor rings '8. These brush units may be conventional or may be constructed along the lines of the brush units it. In the latter case, the insulating bushings need not be made eccentric, and only one unit need engage the ring.

Operation of this commutator brush arrangement is as follows:

Each pair of brush units forms in effect a single commutator brush structure; one of the brush elements indicated by M. making contact with the several segments, and the other brush element designated 33 breaking contact therewith. It is essential that the brush elements M of the two brush structures engage their respective segments in as close synchronisin as possible and that the brush elements it break contact with these segments in synchronisrn. By adjusting the positions oi the eccentric bushings on their bars the efiective width oi brush structure may be varied, or the brush structure as a whole anew/ed. arcuately one or anoth r with respect to the other brash structure in order that the most perfect adjustment may be obtained. Each brush element is made as thin as possible in order to make a fine lineal contact with the commutator so that the effective edge of the brush struc e is accurately defined.

lfiiough have shown and described a par ticular embodiment of this invention, I do not wlshto be limited thereto but desire to in'cor porate in the scope or my invention the constructions, combinations, and arrangements embraced in the appended claim:

1. A commutator brush struotin'e comprising: pair of brush elements disposed in contiguous relation with each other and engageable with a commutator; means electrically coupling said brush elements directly one with the other so that they form in effect a single brush means; and a device for shifting said to and in each other to vary the effective Width of relati o the enact-iv 3. A commutator brush structure comprising: a pairof brush elements electrically connected with each other and together constituting a brush means, one of said brush elements engageable with a commutator to make contact with the segments thereof and the other similarly engageable to break contact with said segments; and means for adjusting said brush elements to vary the efiective width of said brush means.

4. A commutator brush structure comprising: a pair of brush elements each arranged to make a lineal contact with a segmented commutator, said brush elements being electrically connected to define contact making and breaking edges of a common brush means; and a. device for shifting said brush elements to vary the eifective width of said brush means and the position thereof with respect to said commutator.

5. A commutator brush structure comprising: a pair of brush elements electrically connected to form a single brush means; and a device for relatively adjusting said brush elements to vary the effective Width of said brush means, said device including holders for said brush elements, eccentric bushings for said holders, and journals for said bushings.

6. A commutator brush structure comprising: a. pair of brush elements each arranged to make a lineal contact with a segmented commutator, said brush elements being electrically connected to define contact making and breaking edges of a common brush means; and a device for shifting said brush elements to vary the effective Width of said brush means and the position thereof with respect to said commutator, said device including holders for said brush elements, eccentric bushings for said holders, and journals for said bushings.

7. The combination with a commutator and supporting means extending therealong: a brush holder bushing eccentrically mounted on said supporting means; a brush holder journaled on said bushing; and a brush element of sheet material carried by said brush holder and engaging said commutator edgewise to make a lineal contact therewith.

8. The combination with a commutator and supporting means extending therealong: a brush holder bushing eccentrically mounted on said supporting means; a brush holder journaled on said bushing; and a brush element of sheet material carried by said brush holder and engaging said commutator edgewise to make a lineal contact therewith, the contacting portion of said brush comprising a plurality of alined yieldable fingers extending axially along said commutator.

JAMES C. ARNOLD.

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