US3157770A

US3157770A - Sliding contact brushes

Info

Publication number: US3157770A
Application number: US144478A
Authority: US
Inventors: Roland J Beaulieu
Original assignee: Individual
Current assignee: Individual
Priority date: 1961-10-11
Filing date: 1961-10-11
Publication date: 1964-11-17
Anticipated expiration: 1981-11-17

Description

Nov. 17, 1964 R. J. BEAULIEU 3,l57,770

SLIDING CONTACT BRUSHES Filed Oct. 11. 1961 2 Sheets-Sheet 1 Roland J Beau/eu INVENTOR.

Nov. 17, 1964 R. J. BEAULIEU SLIDING CONTACT BRUSHES 2 Sheets-Sheet 2 Filed Oct. ll. 1961 Fig.6

Fig. 5

Roland J Beau/ieu IN VENTOR. do@...

BY EMA:

United States Patent O 3,157,770 SLIDENG CONTACT BRUSEES Roland J. Eeaulieu, 531 hi'ontgonery St, Fall River, Mase. Fiiel Oct. il, 1961, ser. No., %4,478 S Ciams. (Ci. %lil-166) This invention relates to electrical conducting devices, and more particularly to an electrical brush for conducting electrical current or impulses between relatively moving members.

it is the primary object of this invention to provide an electrical brush which has the characteristics of flcxing very rapidly and at the same time always making an eX- cellent contact with the relatively moving member with which it has rubbing contact.

It is still another object of the invcntion to provide a brush which is particularly adapted to be made in eX- tremely small sizes, however, its design permits it to be made in any size desirec.

It is still another object of the invention to provide an electric brush which has built-in guide means to prevent its rubbing surface from moving laterally and maintains the direction of movement of this surface generally normal to the surface with which the brush Contacts.

It is another object of the invention to provide an electric brush which is practically immune from undesirable effects caused by vibration or Shock.

It is still another object of the invention to provide a brush between two reiatively movable surfaces which creates a minimum'amount of torque or drag between the surfaces.

It s still another object of the invention to provide an electrical brush that has an extremely long life and produces a minimum of noise in operation.

It is still another object of the invention to provide an electrical brush which permits exceptional high or low speed operation of the device in which it is used.

It is still another object of the invention to provide an electric brush which has buil^-in vibration dampem'ng means to reduce or eliminate bounce or chatter.

It is yet another object of the invention to provide an electric brush which is not aitected by local changes in temperature and pressure.

It is still another object of the invention to provide an electrical brush which is equally effective regardless of the direction of movement of the surfaces between which it is used.

Briefiy, the invention comprises a resilient brush adapted to be used in rotary switches, analogue converters, motors, digitalizers, telemetering devices, etc.

It is still yet another object of the invention to provide an electronic brush which is relatively simple in design, economical to manuiacture, requires no maintenance and is durable and long lasting in use.

These together with other objects and advantages which will become subsequentiy apparent reside in the details oi` Construction and operation as more fully hereinafter described and claimed, reference being had to the accompanying drawings forming a part hereof, wherein like numerals refer to like parts throughout, and in which:

FIGURE 1 is a perspective View showing my brush mounted between two relatively rotating surfaces with parts broken away;

FIGURE 2 is an enlarged cross sectional view taken substantialiy on the plane of line 2-2 of FIGURE l;

FIGURE 3 is a perspective view of the brush assembly shown in FIGURES 1 and 2;

FIGURE 4- is a vertical cross sectonal View taken substantially on the plane of line 4-4 of PIGURE 3;

FIGURE 5 is a perspective view showing a pair of modified forms of my brushes mounted on an electrical conducting surface;

FIGURE 6 is a perspcctive View showing a third modified form of my invention;

FIGURE 7 is a perspective view showing a fourth modified form of my invention; and

FIGURE 8 is a vertical cross sectional view taken substantially on the plane of line 8 8 in FIGURE 6.

As shown in FIGURES i through 3, one of my brush assemblies 16) is mounted between two relatively

rotating discs

12 and 14. These discs may constitute the components of a Converter or commutator for example.

Disc 12 comprises a lower plate 16 formed of conductive material Secured to an upper plate 13 formed of an insulating material. Disc 14 is composed of a conductive material, but has a plurality of non-conducting inserts Z set into its upper face in a circular pattern concentric about the axis of the disc.

he brush assembly il@ comprises two

opposing spring elements

22 and 24 which are mirror images of one another and are the same size and shape. Brushes are preferably composed of a resilient metal wire having good conductive characteristics such as some of the precious metals.

Each of the

spring elements

22 and 24 comprises an elongated substantially straight mounting portion 26 and a cantiievered arm 23 connected by means of a coiled helical portion 39. The helical portion 3@ forms a torsional spring between the portion 26 and arm 23.

The portion 26 is approximately twice the length of the arm 28 and the central portion of the portion 26 is bulged toward the arm 23 to form a semi-circular ring or hurnp 32. In a similar manner, the arm 28 also has a bulge formed therein which produces a semi-circular ring or hump .34 projecting away from the portion 26.

In the specific application illustrated in FIGURES 1 through 4, the brush assernbly 10 is Secured to the lower surface or" plate te by conventional means such as solder 36'. T he solder 36' maintains the legs spaced in parallel relationship to each other in such a manner that the portions 25, the arms 28 and the axes of the coil springs 30 are substantially parallel to the surface of plate 16. Each spring 22 and 2.4 is positioned as close to one another as permitted by the spacing therebetween caused by the coils of coil spring 30.

A tubular member 36 is inserted between the humps 32 and the surface of plate 16, and a solid cylindrical member 38 is inserted through the coil spring 30.

Members

35 and 38 are preferably formed of silicone rubber. They may be held in position by friction or friction in conjunction with cement.

In operation, the relatively

rotating discs

12 and 14 are spaced apart so as to form a space 4@ therebetween. The outer central portions of the semi-circular rings or humps 34 have surfaces at 42 which act as brush contact surfaces. Due to the spacing between the plates or discs 12 and M, brush surfaces 42 contact the opposing surfaces of the dsc 14 whereby the disc 14 forces the arms 28 inwardly between the humps 32 as shown in FIGURE 2. The arms 28 are of sufcient length to reach to at least the central portions of the humps 32. When the discs 12 and M are rotated relative to one another, the brush surface 42 in conjunction with the remainder of the brush assembly conducts current between the plate 16 and the inserts 20 when the surfaces 42 are contacting the inserts as illustrated in FGURE 2. Due to irregularities in the surfaces of the inserts 2@ and discs 14, the surfaces 14 and arms 28 will be caused to be moved toward and away from the plate 116 as the disc 14 rotates. However, by Contacting and ccmpressing the rubber tubular member 36, the movement and vibration of the arms will be dampened. Also, as the arms 23 move in and out in relation to the humps 32, coil spring 3% will wind and unwind thereby creating a friction on the surface of the cylindrical member 38 thereby further dampening vibration.

Since the extreme outer ends of the arms 28 are maintained between the humps 32, the arms'are positively prevented from moving radially outwardly with respect to the axis of

discs

12 and 14.

In the modification shown in FIGURE 5, the brush assembly 44 is substantially identical to that form shown in FIGURE 3, and consequently similar parts havebeen given identical reference numerals. However, in the form shown in FIGURE 5 the tubular member 36 and cylindrical member 38 have been omitted. Also, the pair of adjacent humps 32 are slightly canted or sloped so thattheir central portions 33 are spaced sufficient distance apart to receive adjacent ends of the arms 28, however, the 'ings or humps 32 converge together in a direction away from the central portions 33 and toward the junctions 35 where the humps terminate. Therefore, the rings or humps 32 are spaced substantially closer together at 35 than they are at 33 thus causing the extreme outer ends of the arms 28 to frictionally contact the inner surfaces of the humps 32 When the arms are pressed downwardly between the humps.

Therefore, it is apparent that when the outer ends of the arms 28 are forced between the humps 32 to spread them apart, the friction between the arms and humps function as a means for dampening vibration in the brush assembly.

In the modification shown in FIGURE 6 two brush assemblies 44 are mounted in diametrical opposed relationship on a disc 12. These brush assemblies 44 are identical to the brush assemblies 46 shown in FIGURE 5 eX- cept that one half of the brush assembly has been omitted.

In this particular arrangement, the humps or rings 32' will only prevent lateral movement of the arm 23' in one direction, preferably the radially outward direction.

In the form shown in FIGURE 7, the brush assembly 48 is identical to that form shown in FIGURE 6 except the humps 34 have been omitted and the arms 28' are therefore straight. A rectangular brush member 59 is mounted on the outer surfaces of these arms and Secured thereto by conventional means. Brush member 50 has a concave surface 52 which is particularly adapted for contacting the convex surfaces of commutators such as those used in conventional motors and generators.

Normally, the various brush assemblies illustrated will be of a very small size only a fraction of the sizes illustrated in the drawings, for example, it has been found that in electronic converters, brushes which are three-eighths of an inch long by one-sixteenth inch high by one-thirtysecond of an inch wide perform very satisfactorily.

The foregoing is considered as illustrative only of the principles of the invention. Further, since numerous modifications and changes will readily occur to those skilled in the art, it is not desired to limit the invention to the exact Construction and operation shown and described,

and accordingly all suitable modifications and equivalents may be resorted to, falling within the scope of the invention as claimed.

What is claimed as new is as follows:

-1. An electrical brush assembly composed of conductive material for conducting current between 'elatively rotating surfaces comprising a base adapted to be connected to one of the surfaces, a member having a contact surface for engaging and sliding on another of the surfaces, resilient means connecting the member to the base, said resilient means comprsing a coil spring which telescopcally receives and retains a resilient cylindrical member.

2. An electrical brush assembly composed of a conductive material for conducting current between relatively rotating surfaces comprising a base connected to one of said surfaces including a pair of parallel fine wires having humps intermediate the ends thereof, a pair of parallel fine wire members having contact surfaces for engaging and sliding on another of said surfaces terminating over said base wires adjacent said humps, resilient means connecting said members to the base wires at one end thereof normally urging said members away from said humps, said contact surfaces located on the sides of the members opposite the base, the terminal portion of said members being latera'lly confined by said humps when said members and base are urged together by said surfaces.

3. A device as defined in claim 2 wherein the humps have diverging opposing side surfaces, the ends of said members adapted to be forced between and friction-aily engaged by said side surfaces.

4. A device as defined in claim 2 wherein said htunp's are vertically spaced from said one surface to define a recess, a resilient tube telescoped within said recess, the terminal portions of said members adapted to contact and compress said tube in operation for clamping vibrations in said brush. c

S. An electrical brush assembly composed of a conductive material for conducting current between relatively rotating surfaces comprising a base connected to one of said surfaces including a fine wire having a hump intermediate the ends thereof, a fine wire member having a contact surface for engaging and 'sliding on another of said surface terminating over said base wire adjacent said hump, resilient means connecting said members to the base wire at one end thereof normally urging said member away from said hump, said contact surface located on the side of the member opposite the base, the 'terminal portion of said member being laterally confined by said hump in at least one direction when said member and base are urged together by said surfaces.

References Cited in the file of this patent UNITED STATES PATENTS Zablocki Dec; 19, 1961

Claims

1. AN ELECTRICAL BRUSH ASSEMBLY COMPOSED OF CONDUCTIVE MATERIAL FOR CONDUCTING CURRENT BETWEEN RELATIVELY ROTATING SURFACES COMPRISING A BASE ADAPTED TO BE CONNECTED TO ONE OF THE SURFACES, A MEMBER HAVING A CONTACT SURFACE FOR ENGAGING AND SLIDING ON ANOTHER OF THE SURFACES, RESILIENT MEANS CONNECTING THE MEMBER TO THE BASE, SAID RESILIENT MEANS COMPRISIG A COIL SPRING WHICH TELESCOPICALLY RECEIVES AND RETAINS A RESILIENT CYLINDRICAL MEMBER.