US2016189A - Brush operating mechanism - Google Patents

Description

@110 L "B3935. J. W. ALLEN Zfiiifidg BRUSH OPERATING MECHANISM Filed Nov. I8, 1933 2 Sheets$heet 1 INVENTOR.

L 1935. J, w ALLEN 2,016,189

BRUSH OPERATING MECHANI SM Filed Nov. 18, 1955 2 Sheets-Sheet 2 Patented a. 1, 1935 UNITED STATES PATENT OFFICE BRUSH OPERATING MECHANISM Application November 18, 1933, Serial No. 698,710

19 Claims.

The present invention relates to dynamo-electric machines and, more particularly, to brush mechanisms for such machines and operating means therefor.

One of the objects of the invention is to provide for machines of the above type novel brush mechanism for operatively connecting the machine to an electric circuit and for interrupting the flow of a current between said machine and circuit.

Another object of the invention is to provide a novel brush-lifting mechanism for a dynamoelectric machine, said mechanism being so constituted that the brushes of the machine may be moved from an inoperative to an operative position in such a manner as to avoid damage to the commutator or collector rings associated with said brushes.

Another object is to provide a novel brush-lifting mechanism adapted to be controlled from a point remote from the dynamo-electric machine, said mechanism being so constructed and arranged that the brushes will be brought into contact with the commutator or collector rings without shock or damage to the elements of the machine.

A further object of the inventionis to provide a novel brush holder.

Still another object is to provide a novel brushlifting mechanism so constructed and arranged as to simultaneously operate a pair of brushes in such a manner that firm engagement of one brush with the commutator or collector rings is obtained even after the other brush has been firmly seated on the commutator before the first brush, thereby assuring proper contact of the brushes with the commutator even though one brush may be Worn more than the other.

Still another object is to provide a brush mechanism of the above type embodying a novel brush holder so constructed and arranged that the brushes are resiliently carried thereby to aid in preventing shock or damage thereto and to the commutator or slip ring with whichthe brushes are associated and also to facilitate the replacement of the brushes when necessary.

The above and other objects and advantages of the invention will appear more fully hereinafter from a consideration of the detailed description which follows, taken together with the accompanying drawings wherein one embodiment of the invention is illustrated. It is to be expressly understoodhowever, that the drawings are for the purpose of illustration and description only and are not designed as a definition of the limits of the invention, reference being had primarily for this purpose to the appended claims.

In the drawings wherein like reference characters refer to like parts throughout the several views: 6

Fig. l is a partial longitudinal section of a dynamo-electric machine embodying the present invention;

Fig. 2 is a top plan view, with parts broken away and partly in section, illustrating the mechanism shown in Fig. 1;

Fig. 3 is a transverse half-section taken on lines 33 of Fig. 2;

Figs. 3a and 3b are detailed perspective views of one form of novel brush holder used in the apparatus embodying the present invention;

Fig. 4 is a front elevation of one of the brushes showing the novel form thereof as used with the brush holder shown in Figs. 3a and 3b; and

Fig. 5 is a fragmentary perspective view of another form of brush holder embodying the present invention.

Referring now to the drawings, the novel brush mechanism of the present invention, as illustrated, is operatively associated with a dynamoelectric machine having a casing It), a field winding I I, a rotor or armature I2, and a commutator or slip ring 13. These elements of the structure may be of any suitable type and per se constitute no part of the present invention. Casing It] is provided with an end portion [4 for enclosing the commutator or slip ring and the novel brush mechanism.

Referring more particularly to Figs. 2 and 3, it will be noted that section 14 carries a pair of insulating members l5 that are preferably formed of bakelite or similar material and are removably secured to the inner surface of said casing section as by means of screws [6.

Attached in any convenient manner, as by means of rivets ll, to each insulating member 15, is a current-carrying bracket I8 having an inwardly extending ear or lug I811 which receives a binding post I9 (Fig. 3) having an electrical conductor 20. In the form shown, bracket I3 is radially spaced from member I 5 by means of washers 2| which may be formed of mica or other suitable insulating material.

The inner end of each bracket I8 is provided with a pivot pin or rod 22 on which is pivotally mounted an arm 23 to the outer end of which is removably and resiliently attached a brush 24. In the illustrated embodiment and, more particularly as shown in Figs. 3a and 3b, arm 23 is provided with a tab which is bent up to form a sleeve 25 in which the brush 24 is carried, the brush being held in an operative position in the sleeve 25 by means of a leaf spring 26 that is pivotally secured at 26a to the top of and extends beyond the outer end of the arm 23. The outer end of spring 26 passes over the top of and engages the brush 24 whereby said brush is yieldingly and removably held in operative position on the arm. The brush 24 has its upper portion enlarged as shown at 24a (Fig. 4) in order to prevent it from slipping through the sleeve 25 when seated therein and held by the spring 26. Means are provided whereby the spring 26 is locked against lateral movement about the pivot 26a when the spring is in engagement with the brush, said means being effective automatically upon movement of the spring into engagement with the brush. In the form shown in Figs. 3a and 3?), said means comprise a pin 21 which is carried by the spring at the inner end thereof, and which is adapted to be seated in a hole 21a provided on the arm 23. It will be seen that when it is desired to replace the brush 24 the inner end of the leaf spring 26 is manually lifted until the pin 21 is out of the hole 21a and the spring is then swung to the left or right of the arm 23 on the pivot 26a, thereby causing the outer end of spring 26 to clear the brush to permit ready removal thereof.

Referring to Fig. 5, it will be apparent that, instead of the pin 21 and hole 21a, a downward indentation 21 may be provided near the inner end of spring 26 and a corresponding indentation 2l on the arm 23 so that when the outer end of the spring is in engagement with the brush, the indentation on the spring will fall into the indentation on the arm, thereby locking the spring to prevent lateral movement thereof until the spring is manually moved sideways. Casing I4 is preferably provided with openings I4a adjacent the brushes in order to facilitate inspection and replacement of the latter.

Means are provided for normally holding the brushes in raised or inoperative position and, as is well understood in the art, when said brushes are thus held, the dynamo-electric machine (a generator in the illustrated embodiment) is disconnected from its associated circuit. For this purpose, each arm 23 has associated therewith a spring 28 which is wound around the pivot pin 22, one end of said spring having engagement with the lower surface of arm 23 while the other end of the spring bears against a stop 29 which projects laterally from bracket l8 immediately below the pivot pin. It will thus be seen that spring 28 tends at all times to hold the brush 24 in inoperative position out of engagement with the commutator I3 if the invention is employed in a direct current machine.

Means are now provided for moving the brushes to operative position against the tension of spring 28, and are so constructed and arranged that the brushes are yieldingly moved'into engagement with the commutator or slip ring in such a manner as to avoid damage to the latter and to themselves. In the form shown, said means include a solenoid 30 embodying a casing 3|, a winding or coil 32 and binding posts 33 adapted to be connected to a suitable source of current (not shown), the energization of said coil 32 by said source of current being controlled by a suitable switch (not shown). In most installations, the switch will be located at a distance remote from solenoid 30. The latter also embodies a plunger constituted by a movable armature 34, one end of which is made in the form of a cone 35 adapted to be seated in a conical recess 35 provided in the core of the coil 33, and to the other end of which is pivotally secured a cylindrical insulating member 3'! having an enlarged lower portion or head 33 the sides of which curve downwardly as shown at 33. The member 37 is pivoted to the end of the armature 34 by means of a pivot pin 40 in order that said member may swing to the right or to the left to a limited extent about said pivot W, as viewed in Fig. 3. The member 3'! is supported within the solenoid 30 in any suitable manner as by means of a bracket or projecting finger 4! carried by the frame 54. The purpose of the limited pivotal movement of the member 37 about the pivot 40 will appear more fully here inafter.

In the illustrated embodiment, the solenoid 30 is fixedly secured to casing section I 1 of the generator by means of a bracket 42 provided with 47 which is located centrally of coil 3'2 and extends through casing Eli, cover plate and into bracket 62 where it terminates at a conical opening 48 provided in said bracket 42 adjacent a similar opening is provided in the casing section M so that the insulating member El may be lifted through said openings upon operation of the armature 3 by the coil In operation, the switch (not shown) is closed to energize co whereupon plunger 34 is moved upwardly in the casing 3i and outwardly relative to casing section 14. The movement of the plunger is transmitted through the pivotal connection 4D to the insulating member 3? whereby the latter is moved upwardly and the inner ends of arms 23 are swung upwardly against the tension of spring 28. The swinging movement of the inner ends of arms 23 is effective to move brushes 24 into engagement with the commutator or slip ring it. Due to the yielding action of springs 28 and that of springs 25, brushes 24 are yieldingly moved into engagement with the commutator or slip ring whereby damage to the latter, such scoring, is prevented. The limited swinging movement of the member 3i about the pivot 40 insures a firm contact of both brushes against the commutator or slip ring inasmuch as the pivotal connection is, in effect, a lest-motion connection whereby one of the arms may continue to move to cause firm engagement of its corresponding brush even after the brush associated with the other arm has been firmly seated on the commutator as sometimes happens when one brush becomes slightly shorter than the other due to wear. For example, if the brush shown at the left in Fig. 3 were shorter than that shown at the right, the latter brush would become seated on the commutator before the former but, by virtue of the pivotal connection between the member 31 and the armature 3d, said member M will swing slightly to the left thus causing continued movement of the arm until the brush at the left is also seated on the commutator even though the brush at the right is already in engagement with the commutator.

There is thus provided a novel brush mecha nism which is so constructed and arranged that the brushes may be moved from inoperative to operative position without damage to the parts of the machine, the control being located at a distance from the machine if desired. The sharp, positive movement resulting from direct solenoid action on the brush-carrying arms is avoided and the flow of 'current between the dynamo-electric machine and its associated circuit is readily controlled. There is also pro-. vided a novel brush holder whereby the operation of the entire mechanism is rendered more eifective, and a novel connection is further provided between the brush engaging member and the solenoid so that said member is permitted a limited swinging movement whereby both brushes are caused to firmly engage the commutator or slip ring even through one of the brushes may be slightly shorter than the other.

The mechanism is particularly adapted for use as a cut-out for the high voltage side of multicurrent engine-driven radio generators such as are extensively employed on aircraft. As will be understood by those skilled in the art, however, the invention is not limited to such use and may be advantageously employed in various types of dynamo-electric machines due to its ready installation and dependable operation. Although only one embodiment of the main invention and two forms of brush holders have been illustrated and described, various changes which will now appear to those skilled in the art may be made in the details of construction and relative arrangement of parts without departing from the scope of the invention. Accordingly, reference will be had to the appended claims for a definition of the limits of the invention.

What is claimed is:

1. In a dynamo-electric machine of the commutator type, a brush for the commutator, an arm carrying said brush, means for yieldingly holding said brush in inoperative position, a solenoid having a plunger operated thereby, a member engaging said arm, and means providing a pivotal connection between said plunger and said member for moving the latter lineally to actuate said arm while permitting pivotal movement of said member whereby said brush is moved to operative position.

2. In an apparatus of the class described, a brush, a pivotally mounted arm carrying said brush, resilient means operatively engaging the arm for holding the brush in inoperative position, an insulating member having an enlarged portion engaging said arm, a solenoid having a plunger, and means pivotally connecting said member to said plunger, said solenoid being adapted to raise said member lineally while permitting pivotal movement thereof whereby said brush is moved to operative position.

3. In a generator of the commutator type, a plurality of brushes, spring-pressed arms extending oppositely of one another for normally holding said brushes out of engagement with the commutator, a solenoid having a movable plunger, and means including a member pivotally connected to said plunger in alignment therewith, said member having an enlarged head engaging each of said arms, and said solenoid being operative through said means to move said brushes into engagement with the commutator, said pivotal connection between said plunger and member providing an angular movement toward one of the brush arms and away from the other whereby the former of said arms may continue to move to cause the firm engagement of its associated brush with the commutator even after the brush associated with the other arm has been firmly seated on said commutator.

l. In a, generator of the commutator type, a plurality of pivotally mounted arms, brushes carried by said arms for engagement with the commutator, resilient means operatively connected to said arms to hold said brushes out of engagement with the commutator, a solenoid having a movable plunger, an insulating member carried by said plunger and having an enlarged portion engaging said arms, and means providing a pivotal connection between said member and said plunger for transmitting movement of the plunger to said member in such a manner that one of the arms may continue to move on its pivot to cause firm engagement of its associated brush with the connnutator even after the brush associated with the other arm has been firmly seated on said commutator.

5. An apparatus of the class described, a pivotally mounted arm, a brush removably secured to one end of said arm, a member having an enlarged portion engaging the other end of said arm, a solenoid having a plunger. operated thereby and pivotally carrying said member, and resilient means for holding said arm in engagement with the enlarged portion of said member.

6. In a dynamo-electric machine, a substantially cylindrical casing, a solenoid mounted on said casing and having a plunger radially disposed with respect to the casing, an insulating member pivotally carried by said plunger, arms engaging said member, brushes carried by said arms, and yielding means for opposing movement of the member and plunger in an outward direction relative to the casing, said pivotal connection between member and plunger providing angular movement of said member toward one of the arms and away from the other whereby the former may continue to move to cause firm engagement of its associated brush with the commutator even after the brush associated with the other arm has been firmly seated on said commutator.

7. In a dynamo-electric machine a brushholder, a brush, electrical means including two pivotally connected members, both of which are adapted to move rectilmearly but one of which is also adapted for limited angular movement with respect to the other for moving the brush into operative position, resilient means for opposing said movement of the brush, and another resilient means pivotally mounted on the brushholder for holding the brush therein and for preventing shock to the brush upon its being moved into operative position.

8. In a generator of the commutator type, a pair of pivotally mounted arms extending in opposite directions from a radial line of the commutator at the periphery thereof, brushes carried by said arms at their outer ends for engagement with the commutator, resilient means operatively connected to said arms to hold said brushes out of engagement with the commutator, a solenoid having a plunger movable along said radial line from which the brush arms extend, a member carried by said plunger in substantial alignment therewith and having means engaging said arms, and means providing a pivotal connection between said member and said plunger for transmitting linear movement of said plunger to said member While permiting angular movement of said member so that one of said brush arms may continue to move on its pivot to cause firm engagement of its associated brush with the commutator even after the brush associated with the other arm has been firmly seated on said commutator.

9. In a generator of the commutator type, a pair of pivotally mounted arms, brushes carried by said arms, resilient means operatively connected to said arms to hold said brushes out of engagement with the commutator, and means movable rectilinearly between said arms and engaging the latter to move the brushes into engagemcnt with said commutator, said means including a member having a pivotal movement toward and away from the brush arms while moving rectinlinearly so that one of said brush arms may continue to move on its pivot to cause firm engagement of its associated brush with the commutator even after the brush associated with the other arm has been firmly seated on said commutator.

10. In a generator of the commutator type, a pair of pivotally connected arms extending in opposite directions from a radial line of the commutator at the periphery thereof, brushes carried by said arms at their opposite ends for engagement with the commutator, resilient means operatively connected to said arms to hold said brushes out of engagement with said commutator, and means movable rectilinearly between said arms along said radial line and including means engaging said arms and capable of pivotal movement toward one arm and away from the other while moving rectilinearly so that the former arm may continue to move on its pivot to cause firm engagement of its associated. brush even after the brush associated with the other arm has been firmly seated on said commutator.

11. In a generator of the commutator type, a pair of brushes normally out of engagement with the commutator, means movable along a radial line of the commutator for simultaneously moving said brushes into engagement with said commutator, and means carried by said first-named means for permitting continued movement of one brush into firm engagement with the commutator even after the other brush has been firmly seated on said commutator whereby both of said brushes engage the commutator even though one may be slightly shorter than the other.

12. In a. brush operating mechanism for moving a pair of brushes into engagement with a commutator of a dynamo-electric machine, means movable along a radial line of the commutator for permitting continued movement of one brush into firm engagement with the commutator even after the other brush has been firmly seated on said commutator.

13. In a brush operating mechanism of the type employing remotely-operated means for actuating the brushes into engagement with a cooperating commutator of a dynamo-electric machine, the combination of a brush-holder pivotally mounted for actuation by said actuating means and comprising an arm having a brushreceiving member at one end thereof into which a brush is adapted to be inserted, a brush in said member, a spring pivotally secured to said arm to move laterally thereof and having one end engaging the brush to hold the latter in said member and to provide resiliency thereto for preventing excessive impact of the brush against the commutator upon operation of the actuating means, and means effective upon lateral move ment of said spring about its pivot into engagement with the brush to lock said spring in engaged position to prevent disengagement thereof from the brush.

14. In a brush operating mechanism of the type employing remotely-operated means for actuating the brushes into engagement with a cooperating commutator of a dynamo-electric machine, the combination of a brush-holder pivotally mounted for actuation by said actuating means and comprising an arm having a brushreceiving member at one end thereof into which a brush is adapted to be inserted, a brush in said member, a spring pivotally secured to said arm to move laterally thereof and having one end engaging the brush to hold the latter in said member and to provide resiliency thereto for preventing excessive impact of the brush against the commutator upon operation of the actuating means and means effective upon lateral movement of said spring about its pivot into engagement with the brush to lock said spring in engaged position to prevent disengagement thereof from the brush and means normally maintaining said brush-holder in non-engaging position.

15. In a brush operating mechanism of the type employing remotely-operated means for actuating the brushes into engagement with a cooperating commutator of a dynamo-electric machine, the combination of abrush-holder pivotally mounted for actuation by said actuating means and comprising an arm having a brush receiving member at one end thereof into which a brush is adapted to be inserted, a brush in said member, a spring pivotally secured to said arm to move laterally thereof and having one end engaging the brush to hold the latter in said member and to provide resiliency thereto for preventing excessive impact of the brush against the commutator upon operation of the actuating means, and means for locking the spring in engaged position with the brush as said spring is brought into engagement therewith.

16.111 a brush-operating mechanism of the type employing remote1yoperated means for actuating the brushes into engagement with a cooperating commutator of a dynamo-electric machine, the combination of a brush-holder pivotally mounted for actuation by said actuating means and comprising an arm having a sleeve at one end thereof into which a brush is adapted to be inserted, a brush in said sleeve and having an enlarged upper portion to prevent it from slipping through said sleeve, a leaf spring pivotally secured to said arm to move laterally there of and having one end engaging the brush to hold the latter in said sleeve and to provide resiliency thereto for preventing excessive impact of the brush against the commutator upon operation of the actuating means, and means for looking the spring in engaged position with the brush upon said spring being brought into engagement with said brush.

17. A brush holder comprising an arm, a brush receiving member at one end of arm into which a brush is adapted to be inserted, a brush in said member, a spring pivotally secured to said arm for lateral movement with respect thereto and having one end engaging the brush to hold the latter in said member and to provide resiliency thereto when engaging a commutator, and means for automatically locking the spring in engaged position with the brush upon said spring being brought into engagement therewith.

18. A brush-holder comprising an arm, a brush-receiving member at one end of said arm into which a brush is adapted to be inserted, a brush in said member, a spring pivotally secured to said arm for lateral movement with respect thereto and having one end engaging the brush to hold the latter in said member and to provide resiliency thereto when engaging a commutator, and means associated with one end of said spring for automatically looking it in engaged position with the brush upon said spring being brought into engagement therewith.

19. A brush-holder comprising an arm, a brush-receiving member at one end of said arm into which a brush is adapted to be inserted, a

tion to prevent disengagement thereof from the 19 brush.

JOSEPH WILLIAM ALLEN.

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