US3133218A - Holder for extra-long carbon brushes - Google Patents

Description

May 12, 1964 H. R. HARRIS HOLDER FOR EXTRA-LONG CARBON BRUSHES 3 Sheets-Sheet 1 Filed Feb. 13, 1961 y 2, 1964 H- R. HARRIS 3,133,218

HOLDER FOR EXTRA-LONG CARBON BRUSHES Filed Feb. 13, 1961 5 Sheets-Sheet 2 BY M May 12, 1964 H. R. HARRIS 3, 33,218

HOLDER FOR EXTRA-LONG CARBON BRUSHES Filed Feb. 13, 1961 3 Sheets-Sheet 3 wa I IN VEN TOR. flaw/v19 A? flaw/a United States Patent Oilice 3,133,218 Patented May 12, 1964 3,133,218 HOLDER FOR EXTRA-LONG CARBON BRUSHES Herman Ray Harris, Grosse Pointe Woods, Mich, assignor, by mesne assignments, to Herman R.

Iarris, Grosse llointe Woods, Mich.

Filed Feb. 13, 1961, Ser. No. 88,930

i 1 Claim. (61. 310-246) The invention refers to brush holders and relates more specifically to improved means for holding and applying regulated pressure to extra long conductive brushes dur ing the entire life thereof while the brushes are in use.

In the past brushes used in conjunction with collector rings, exciters and similar electric apparatus in conjunction with power generation and transfer have been relatively short so that they are completely used up in a period shorter than that required between maintenance and inspection shut-down of apparatus, such as boilers, with which they are associated. The periods between shutdowns of the apparatus has in the past therefore been determined by the life of the brushes. Since shutting down of the apparatus with which the brushes are associated is a relatively expensive procedure and may damage apparatus such as boilers, it is desirable to use brushes which have at least as long a useful life as the normal maintenance and inspection period determined by the apparatus with which they are associated.

The brushes to function elficiently must, however, have a substantially constant pressure exerted thereon. In the past it has been found extremely difficult to exert such constant pressure on brushes of suficient length to have a useful life equal to the maintenance time of the other apparatus with which the brushes are associated. Where devices capable of applying the required constant pressure to extra long brushes have been provided they have been relatively complicated whereby the expense and reliability thereof have prevented their generaluse.

It is therefore one of the purposes of the present invention toprovide an improved brush holder for extra long brushes whereby substantially constant pressure may be applied to the brush during the entire useful life thereof. Another object is to provide a brush holder for extra long conductive brushes including improved automatic means for exerting substantially constant pressure on the brushes for theentire useful life thereof.

Another object is to provide a brush holder for extra long conductive brushes including a holder box for guiding a brush during use thereof including means for attachment to the apparatus with which the brush is used, a spring holder releasably secured to the holder box and a constant pressure spring secured to the spring holder forexerting a constant pressure on a conductive brush passing through the holder box. I

Another object is to provide a brush holder as set forth above and further including a guard member secured to the holder box and surrounding the spring and spring holder which guard permits ventilation and visual inspec tion of the position of the brush. p Another object is to provide a brush hold-er as set forth above wherein the spring is positioned at right angles to the spring holder whereby the spring is better positioned to exert a constant pressure on a brush used with existing holder boxes as the brush is worn away.

Another object is to provide a brush holder for extra long conductive brushes comprising a holder box for guiding a brush passed therethrough toward the apparatus with which it is associated, means for mounting a spring on the holder box for exerting regulated pressure on the brush, and means for periodically adjusting the regulated pressure applied to the brush Whilethe apparatus associated with the brush is in operation.

Another object is to provide a brush holder as set forth above including means for visually indicating the regulated pressure applied to the brush.

Another object is to provide a brush holder as set forth above wherein the means for adjusting the regulated pressureapplied to the brush may be manually actuated with one hand.

Another object is to provide a brush holder as set forth above including means for pivoting the spring for applying pressure to the brush out of its operating position to permit easy installation of a new extra long brush in the holder box.

Another object is to provide a brush holder for extra long conductive brushes comprising a holder box for guiding a brush into engagement with electrical apparatus associated therewith, a post secured to the holder box, a carriage guided on and movable longitudinally of the post axially of a brush passed through the holder, resilient means for engaging the top of the brush secured to the carriage, and a substantially constant pressure spring mounted on the carriage and secured to the post for exerting a constant pressure through the carriage on the brush.

Another object is to provide a brush holder as set forth above wherein a signle post, carriage and constant pressure spring is utilized to produce substantially constant pressure automatically on a pair of brushes.

Another object is to provide a brush holder as set forth above wherein the carriage includes means for initially adjusting the constant spring pressure.

Another object is to provide a brush holder as set forth above which is simple in construction, economical to manufacture and eiiicient in use.

Other objects and features of the invention will become apparent as the description proceeds, especially when taken in conjunction with the accompanying drawings, illustrating preferred embodiments of the invention, wherein:

FIGURE 1 is an elevation View of a brush holder for extra long conductive brushes constructed in accordance with the invention.

FIGURE 2 is a view of the brush holder shown in FIGURE 1 taken on the line 2-2 in FIGURE 1. 1

FIGURE 3 is a cross section of the brush holder shown in FIGURE 1 taken on the line 33 in FIGURE 1.

FIGURE 4 is a partly broken away elevation view of a modification of the brush holder shown in FIGURE 1.

FIGURE 5 is a partially broken away elevation view of the brush holder shown in FIGURE 4 taken in the direction of arrow 5 in FIGURE 4.

FIGUREG is an elevation view of a further modification of the automatic brush holder shownin FIGURE 1.

FIGURE 6A is an elevation view of still another modification of the brush holder of FIGURE 1. FIGURE 7 is an elevation View of a manually adjustable holder for extra long conductive brushes constructed in accordance with the. invention. I

FIGURE 8 is an elevation View of the brush holder shown in'FIGURE 7 taken in thedirection of arrow 8 inFIGURE7.'

FIGURE 9 is a cross section of the brush holder shown in FIGURE 7 taken on the line 99 in FIGURE 7. 1

FIGURE 10 is an elevation view of a modification of the brush holder illustrated in FIGURE 7; i

FIGURE 11 is an elevation view of another automatically adjustable brush holder for extra long conductive brushes constructed in accordance with the invention.

FIGURE 12 is an elevation view of the brush holder illustrated in FIGURE 'll'taken in the direction of arrow 12 in FIGURE 11. t

FIGURE 13 is a top view of the brush holder illustrated in FIGURES 11 and 12.

FIGURE 14 is an elevation view of a modification of the brush holder illustrated in FIGURES lll3.

With particular reference to the figures an embodiment of the present invention will now be disclosed.

The brush holder of FIGURES 13 comprises a holder box In, spring holder 12 and constant pressure spring 14. In operation the holder box It? is secured to electric apparatus, such as a generator (not shown) with the extra long conductive brush16 passed therethrough to make contact with the collector rings, exciter commutator or similar part (not shown) of the electric apparatus. A constant pressure is exerted on the brush during the entire useful life thereof by means of spring 14 so that the electric contact resistance provided through electric conductor 18 does not vary due to wear of the brush 16 in use.

More specifically the holder box It) which may be shaped substantially as shown in FIGURES 13 includes the passage 20 therethrough through which the brush 16 is passed for guided movement toward the electric apparatus (not shown) from which it is desired to conduct an electric current with the brush 16. The holder box It) is further provided with an elongated opening 22 through which a bolt may be passed to adjustably secure the holder box to rigid mounting means, such as the electric apparatus with which the brush holder is associated. A button rivet 24 is secured to the holder box It) by convenient means such as silver solder so that the head 26 thereof is in spaced relation to the surface 28 of the holder box.

The U-shaped spring holder 12 is provided with an elongated slot 36 in end 32 thereof through which the head 26 of the button rivet 24 extends to removably secure the end 32 of the spring holder 12 to the holder box 10. The other end 34 ot the spring holder 12 is secured to the holder box by means of the removable wing nut 36 threaded on the stud 38 carried by the holder box 10.

The spring 14 is secured to the end 34 of spring holder 12 by convenient means such as rivets 40. The spring 14 may be of steel or other suitable material and is of the constant pressure type. That is to say that spring 14 exerts a constant pressure on the holder 42 which is secured to the brush 16 by convenient means, such as the rivet 44. Such springs are known per se and will not therefore be considered in detail herein. Conductor 19 is secured to rivet 44 and serves to transfer electric energy from the brush 16 which may be the usual carbon brush or which may be constructed of other suitable electrical conductive material such as graphite or copper.

In operation of the brush holder shown in FIGURES 1-3 it will be assumed that a new extra long brush, for example one six inches long is installed in the brush holder of the invention. During usage of the electric apparatus with which the brush holder is associated the brush 16 will be gradually worn away as is well known. As the brush 16 is worn away the constant pressure spring 14 coils automatically and approaches the opening through the holder box 10. Due to the nature of the constant pressure spring 14 a force of the same magnitude is applied axially of the brush 16 until the brush is sub-j stantially entirely worn away by the electric apparatus associated with the brush holder.

Thus it can be seen that through the provision of an extremely simple brush holding device an extra long brush may be used in conjunction with electric apparatus from which it is desired to conduct electric energy which brush need not be changed between maintenance of the electric apparatus with which it is associated and which brush conducts a constant electric current from the electric apparatus due to the constant pressure applied to the brush regardless of the length thereof automatically by the spring 14. I

A modification of the brush holder shown in FIGURE 1 is illustrated in FIGURES 4 and 5. The brush holder illustrated'in FIGURES 4 and 5 comprises a holder box 46 similar to the holder box Ill and having the spring holder 48 and ventilated guard 50 secured thereto. The spring holder 48 includes the L-shaped bracket 52 secured thereto and extending transversely thereof as shown.

The constant pressure spring 54 similar in all respects to the constant pressure spring 14 is secured to the bracket 52 by convenient means, such as rivet 56 so that the spring holder 43 and spring 54 are positioned at right angles to their position in the brush holder illustrated in FIGURES 1-3. Such positioning of the spring 54 has distinct advantages when the constant pressure spring 54 is used in conjunction with standard box holders 46 in that with such positioning the spring 54 provides a constant pressure on the brush 58 without interference therewith of the box holder 46 when the brush is worn away. Guard is provided to protect the spring 54 from contact with objects which might destroy the constant pressure exerted thereby.

Another modification of the extra long brush shown in FIGURE 1 is illustrated in FIGURE 6. The brush holder illustrated in FIGURE 6 includes the holder box 65? having the opening 62 therethrough through which the brush 64 is guided as before. The constant pressure spring 66 is secured to the holder box 60 by convenient means 68 so that the spring 66 exerts a constant axial pressure on the brush 64 during use thereof as the brush 64 is worn away by the electric apparatus with which it is associated.

The ventilated guard and spring guide 70 which extends around three sides of the carbon brush 64 is pivotally secured to the holder box 60 at 72. A slot 74 is provided in the upper portion 75 of guard 70. The periphery of the slot 74 may be clamped between the lock nut 76 on threaded stud 77 and the flange 79 of holder box 66 to lock the guard 76 in the position shown in FIGURE 6.

The spring guide and guard 70 is further provided with an elongated slot 78 therein through which the length of the brush 64 may be observed. When it is desired to change the brush 64 the lock nut 76 is loosened, the guard 70 is pivoted about pivot 72 to provide access to the constant pressure spring 66 which may be held in an uncoiled extended position while a new brush 64 is placed in the passage 62.

FIGURE 6-A illustrates a brush holder including many of the more desirable features of the brush holders of FIGURES 1 and 6. The brush holder of FIGURE 6-A comprises the holder box 61 similar to holder box 60 and an L-shaped spring holder and spring guide 69 similar to spring holder and guide 12. Spring holder and guide 69 is secured to the holder box 61 at the top by lock nut 71 and at the bottom by wing nut 73 similar to lock nut 76 and wing nut 36. Operation of the brush holder of FIG- URE 6-A is similar to the operation of the brush holder of FIGURE 1. V

The brush holder shown in FIGURE 7 comprises a holder box 80 for guiding the extra long brush 82 toward electric apparatus with which the brush holder is associated. Fulcrum plate means 84 for applying a regulated pressure to the brush 82 and adjusting and locking means 86 for manually adjusting the regulated pressure applied to the brush 82 and locking the adjusting mechanism in adjusted position are also provided in the brush holder illustrated in FIGURE 7.

The holder box 80 is provided with the passage 88 therethrough through which the brush 82 extends axially. An elongated slot 96 is provided in the holder box 80 to permit adjustably securing the holder box to the electric apparatus with which it is associated by convenient means (not shown). Holder box 80 further includes the brackets 92 and 94. Bracket 92 rotatably receives the end 96 of adjusting screw 98 therein. Bracket 94 is provided with a passage 100 therethrough in which the adjusting screw 98 is also rotatably received.

The fulcrum plate means 84 for applying a regulated pressure to the brush 82 comprises the compression spring 102 secured to the U-shaped bracket 104 at one end and to the abutment 106 at the other. The U-shaped bracket 104 as shown is secured to the fiange 108 of the pivotally mounted bracket 110. Bracket 110 is secured to a carrier 112 by pivot pin 114 and locked in a fixed position by means of cotter pin 116. Thus with the carrier 112 positioned along adjusting screw 98 as desired any pre determined pressure within the pressure range of the spring 102 may be exerted on the brush 82.

The shaft 118 which extends vertically from the abutment 106 through the U-shaped bracket 104 and flange 108 is provided with annular ridges 120 thereon which indicate the compression in the spring 102. Each visible ridge may represent a particular spring pressure, such as one pound. Thus, if two ridges are visible the spring in its compressed condition would indicate two pounds of pressure being applied to the brush 82. The pressure exerted on the brush 82 may therefore be kept within required limits by periodic observation of the ridges 120 and resetting of the position of the carriage 112 as the brush is Worn away. A tubular shaft guide 121 flared at each end and pressed into an opening 123 through brackets 104 and 110 is provided to prevent the ridges 120 from catching on the opening 123 and to insure axial movement of the shaft 118.

The adjusting and locking means 86 for adjusting the regulated pressure applied to the brush 82 by the spring 102 comprises the adjusting screw 98 rotatably supported by the holder box 88, the carriage 112 having feed nut 122 fixedly secured thereto, collar 124 rigidly secured to the adjusting screw 98 for rotation therewith, locking wing nut 126 and adjusting handle 128.

In adjusting the position of the carriage 112 to adjust the regulated pressure applied to the brush 82 by the spring 102 the wing nut 86 is first loosened. The adjusting screw 98 is then rotated within the brackets 92 and 94 to cause the feed out 122 to travel along the adjusting screw 98 whereby the carriage 112 is positioned axially of the adjusting screw 98. The wing nut 126 is then again tightened to lock the adjusting screw in position. It will be noted that the entire adjustment may be accomplished with one hand so that a safety feature is provided when the pressure exerted on the brush 82 is adjusted while the electric apparatus with which the brush is associated is operating.

When it is desired to replace the brush 82 the pin 116 is removed from the bracket 110 so that the bracket 118, flange 188 and spring 102 may be pivoted about pivot pin 114 to provide room for easy insertionof a new extra long brush 82 into the passage 88. The member 118 carrying the flange 108 and spring 102 is then pivoted back into the position shown and the cotter pin 116 is again secured through the aligned opening in the carrier 112 and bracket 110 as shown in FIGURES 7 and 8.

A modification of the manually adjustable holder for extra long rods, as shown in FIGURES 79, is illustrated in FIGURE 10. The modified brush holder illustrated in FIGURE includes adjusting and locking means 130 similar to that of the brush holder of FIGURES 7 9 which will therefore not be considered in detail. Similarly the holder box 132 of the box holder shown in FIGURE ,10 will not be described in detail except to indicate that a track 134 is provided on both sides of the upwardly extending portion 136 thereof along which the carriage 140 is guided by means of flanges 142 during adjustment of the adjusting screw 144.

The means 146 for applying a regulated pressure to the brush 148 of the brush holder illustrated in FIGURE 10 has the advantage of being simpler in construction than that provided in FIGURES 7-9 but cannot be pivoted out of the way during replacement of the brush 148 as with the means 84 of the brush holder shown in FIG- URES 7-9.

The brush holder for extra long carbon brushes illus- 6 trated in FIGURE 11 also includes a holder box 150 having a passage 152 therethrough adapted to receive the brush 154 for axial movement toward an electric apparatus (not shown) as before, a carriage 156 for supporting constant pressure means 158 operable to exert a constant axial pressure on the brush 154 and post 160 along which carriage 156 travels as the brush 154 is worn away.

Holder box 150 may be secured to the electric apparatus with which the brush holder is associated by convenient means (not shown). Post 168 is secured to the holder box 151) by convenient means such as the flange 162 and bolts 164.

Carriage 156 comprises side plates 166 and 168 spaced from each other by sleeves 170 extending therebetween and assembled therewith by means of screws 172.- Two sleeves 170 are provided in vertically spaced relation on one side of the post 168 and a sleeve and roller 161 are provided in vertically spaced relation on the other side of post 160, as shown best in FIGURE 11, whereby only vertical movement of the carriage 156 with respect to the post 161) is possible. Roller 161 also serves to guide spring 158.

A further rotatable shaft 174 is provided between the plates 166 and 168 having an axially extending slot 176 therein through which the end 178 of the constant pressure spring 158 is inserted. The other end of the constant pressure spring 158 is secured to the post 160 in the position shown by convenient means such as the screw 180. Thus in operation, as the brush 154 is worn away the carriage 156 is caused to move toward the holder box 1541 as the constant pressure spring 158 coils about the shaft 174 to exert a constant pressure on the brush 154.

The shaft 174 is further provided with radially enlarged portions 182 at the ends thereof having radial recesses therein into which pegs 184 may be inserted to initially adjust the tension of the spring 158 so that each spring in a multiple installation will provide the same pressure on the brushes 154 in the installation regardless of manufacturing imperfections in the springs and/ or slight permanent set of the springs.

The force exerted by the spring is transferred from the carriage 156 to the brush 154 by means of the screw 184.

FIGURE 14 illustrates a modification of the brush holder shown in FIGURES 11-13 wherein a pair of brushes 185 and 188 are provided with regulated pressure axially thereof by means of a brush holder, as shown in FIG- URES 1113, wherein the force is transferred from the carriage 198 to the brushes 186 and 188 by the bolt 192 having the U-shaped bracket 194 sleeved thereon and urged axially outwardly thereof by means of the spring 196. The bracket 194 is loosely sleeved on the bolt 192 whereby slight tilting of the bracket 194 is possible in operation so that pressure on the brushes 186 and 188 will automatically be maintained equal.

While both automatically and manually adjustable brush holders constructed in accordance with the invention have been specifically disclosed together with particular modifications thereof it will be understood that many other modifications of the brush holder of the invention will readily suggest themselves to those skilled in the art. It is therefore the intention to include all such modifications within the scope of the invention.

The drawings and the foregoing specification constitute a description of the improved holder for extra long carbon brushes in such full, clear, concise and exact terms as to enable any person skilled in the art to practice the invention, the scope of which is indicated by the appended claim.

What I claim as my invention is:

A holder for an extra long carbon brush for use in maintaining controlled contact between the brush and electric apparatus with which the brush is used, comprising a substantially L-shaped holder box including a first portion having an opening therethrough adapted to receive a brush and guide the brush toward the electric apparatus and a second portion substantially perpendicular to the first portion having a flange thereon with a threaded opening therein extending substantially parallel to the first portion and in the same direction, an L shaped spring holder having openings through both ends thereof, a bolt extending through the opening in one end of said spring holder threadedly engaging the opening in the flange of said second portion of said holder box for securing said one end of said spring holder to said holder box, a threaded stud secured to the first portion of said holder box extending through the opening in the other end of said spring holder, a nut threadedly engaging said threaded stud for releasably securing the other end of said spring holder to said holder box and a constant pressure spring secured to said 8 spring holder adjacent said other end thereof for exerting a constant pressure on a brush guided by the holder box as the brush is worn away in use.

References Cited in the file of this patent UNITED STATES PATENTS 1,994,502 Burnite Mar. 19, 1935 2,602,100 McDonald July 1, 1952 2,629,061 Swarthout Feb. 17, 1953 2,695,968 Welch et al. NOV. 30, 1954 2,769,107 Potter Oct. 30, 1956 2,836,745 Gillie May 27, 1958

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