US2854647A

US2854647A - Slip ring assembly

Info

Publication number: US2854647A
Application number: US503042A
Authority: US
Inventors: John B Nugent
Original assignee: Individual
Current assignee: Individual
Priority date: 1955-04-21
Filing date: 1955-04-21
Publication date: 1958-09-30
Anticipated expiration: 1975-09-30

Description

Sept. 30, 1958 J. B. NUGENT sup RING ASSEMBLY Filed April 21, 1955 FIG.5

FiG.4

FIGS

JNI 'ENTOR' JOHN B. NUGENT ATTYS United States Patent SLIP RING ASSEMBLY John B. Nugent, Winthrop, Mass., assignor, by mesne assignments, to the United States of America as represented by the Secretary of the Navy Application April 21, 1955, Serial No. 503,042

4 Claims. (Cl. 339-) The present invention relates to :a slip ring assembly and more particularly to a drum type slip ring assembly that is assembled from prefabricated parts.

Various types and sizes of slip ring assemblies have been employed to conduct current between rotating and stationary elements. Slip ring assemblies are mainly of two types, there being a flat or pancake type assembly and a drum type assembly. The present invention is of the latter or drum type design.

Heretofore drum type slip ring assemblies which are assembled from prefabricated parts have had either split or solid collector rings stacked on an insulating core. The use of solid type collector rings normally provides for a better slip ring assembly since these rings are stronger and also since they are symmetrical they provide for a balanced construction that performs more satisfactorily under high speed conditions. Drum type assemblies usually consist of collector rings and insulating rings alternately stacked on an insulating core and squeezed together. When an assembled unit is comprised of a large number of rings, the thickness of each ring and insulator must be held to close tolerances so that the associated brush assemblies will aline with the proper collector rings.

The present invention provides a new and improved slip ring assembly that can readily be assembled, and the alternate stacking of the rings and insulators is controlled so that the brush assemblies will engage with the proper collector rings. In the invention disclosed herein, the collector ring spacing is fundamentally determined by the spacing of grooves that are cut into the core of the assembly. These grooves are accurately located and are used to regulate the build-up of the assembly. Split locating rings are positioned axially by the grooves in the core and these split rings are held in place radially by collector rings. Insulating spacers separate adjacent collector rings. The assembled core is rotatably mounted in bearings inside :a case, and brush assemblies are positioned in the case and are spring biased to provide contact with the collector rings. It is therefore a general object of the present invention to provide an improved drum type slip ring assembly that can be readily assembled from fabricated parts.

Other objects and many of the attendant advantages of this invention will be readily appreciated as the same becomes better understood by reference to the following detailed description when considered in connection with the accompanying drawing wherein:

Fig. 1 is a top plan view of the invention;

Fig. 2 is a sectional view taken on line 2--2 of Fig. 1;

Fig. 3 is a fragmentary view of a core showing grooves therein;

Fig. 4 is a plan view of a split ring,

Fig. 5 is a plan View showing a split ring fitted inside a collector ring; and

Fig. 6 is a sectional view of a brush assembly.

Referring now to the drawing, wherein like reference characters designate like or corresponding parts throughout the several views, there is shown in Figs. 1, 2, and 3 a tubular core 11 which is rotatably mounted in a case 12 by means of bearings 13. The tubular core 11, which is preferably made of non-conducting material such as a phenolic material, has grooves 14 that are cut integral therein. The embodiment shown herein has twenty-one grooves, however, it should be understood that a lesser or greater number could be employed without departing from the scope of the invention.

Split rings 15, each having first and second segments, one of which is shown in Figs. 4 and 5 of the drawing, can be fabricated from either electrically conducting or non-conducting material. If the tubular core 11 is made of non-conducting material then the split rings 15 can be metallic as the tubular core 11 will prevent grounding. However, if the tubular core 11 is made of an electrically conducting material the split rings 15 would have to be made from non-conducting material. One split ring 15 is positioned in each groove 14 and held in position radially by a collector ring 16. The outside diameter dimension of the split ring 15 is greater than the outside diameter of the tubular core 11 and the inner diameter of the collector ring 16 is close fitted to the outside diameter of the split ring 15. The collector rings 16 should be fabricated from a material that has good electrical conducting properties. An electrically insulating spacer 17 separates adjacent collector rings 16.

Referring particularly to Fig. 2 of the drawing it can be seen that the tubular core 11 has an enlarged diameter portion 18 that fits the inside diameter of the bearing 13. An insulating washer 17 is adjacent this enlarged diameter portion 18 and the split rings 15 are positioned in the grooves 14 and held therein by the collector rings 16. The outside diameter of the insulating spacers 17 is greater than the outside diameter of the collector rings 16 and thus a track or groove is formed to keep a brush 19 in contact With the collector ring 16. An end spacer 20 having an outside diameter to fit the bearing 13 is fitted over the smaller end of the tubular core 11 and a small retaining ring 21 is seated in a groove and holds the end spacer 20, the collector rings 16, and insulating spacers 17 in position. The tubular core 11 has a flange 22 that contacts the inner race 23 of one bearing 13 and a large retaining ring 24 contacts the inner race of the other bearing 13, thus locking the assembled tubular core 11 in position. The tubular core 11 has an inner bore 25 that permits lead wires 26 to pass through and out of the radial holes 27 in the tubular core 11. Each lead wire 26 is electrically connected, as by soldering, to a lug 28 on each collector ring 16.

Referring now to Figs. 1 and 2 of the drawing it can be seen that there are seven rows of brush assemblies 29 extending radially of the case 12. Each row has three brush assemblies 29, making a total of twenty-one brush assemblies 29, one brush assembly for each collector ring 16. It is to be understood, of course, that a greater or lesser number of collector rings 16 and brush assemblies 29 could be used without departing from the scope of the invention, the number of collector rings 16 being shown for purposes of illustration only.

The brush assemblies 29 as shown in Figs. 2 and 6 of the drawing, have a brush 19 that is secured, as by welding, to a shaft 31 which is guided in a pair of bushings 32. A coil spring 33 fits about outside diameters of the bushings 32 and biases the brush 19 against the collector ring 16. The case 12 is bored so that the bushings 32 can be slip fitted therein and a retaining ring 34 holds the brush assemblies 29 in position. Lead wires 26 are secured, as by soldering, to the end of the shaft opposite the brush 19.

In operation, the tubular core 11 might either be stationary and have the case 12 rotate about the tubular core ill or the tubular core 11 might be rotatable and the case 12 be stationary. In either situation when there is relative motion between the tubular core 11 and the case 12, there will be relative motion between the collector rings 16 and the brushes 19.

Obviously many modifications and variations of the present invention are possible in the light of the above teachings. It is therefore to be understood that the invention may be practiced otherwise than as specifically described.

What is claimed is:

1. A collector ring assembly comprising a tubular core having a plurality of side by side circumferential grooves therein, a split ring having first and second segments in each of said grooves, electrically conductive collector rings encircling each of said split rings, and insulating spacers adjacent each side of said collector rings.

2. A slip ring assembly comprising a tubular core having radial holes therein, said core having a plurality of side by side circumferential grooves, a split ring having first and second segments in each of said grooves, an electrically conductive collector ring encircling each of said split rings, at least one insulating washer adjacent each side of said collector rings, a separate lead electrically connected to each said collector ring, said leads extending through said tubular core and said radial holes, and contacting means for slidably engaging each said collector ring.

3. A slip ring assembly comprising a case, a tubular core rotatably mounted in said case, said tubular core having radial holes therein and a plurality of axially spaced circumferential grooves, a split ring of insulating material having first and second segments in each of said grooves having an outside diameter greater in dimension than the outside diameter of said tubular core, an electrically conductive collector ring encircling each of said split rings, at least one electrically insulating washer adjacent each side of said collector rings, a separate lead electrically connected to each of said collector rings, said leads extending through said tubular core and said radial holes, and contacting means in said case for slidably engaging each said collector ring.

4. A slip ring assembly as set forth in claim 3 wherein said contacting means in said case comprises a brush assembly having a brush connected to a shaft, said shaft being guided in bushings, and spring means for biasing said brush in engaging contact with said electrically conductive collector rings.

References Cited in the file of this patent UNITED STATES PATENTS 1,756,004 Barr et al. Apr. 22, 1930 2,471,808 Baker May 31, 1949 2,494,244 lonard et al. Jan. 10, 1950 FOREIGN PATENTS 715,495 Germany Jan. 2, 1942