US1403220A - Centrifugal switch - Google Patents

Description

H. L. ZABRISKIE.

CENTRIFUGAL SWITCH.

APPLICATION FILED APR. I9. 1920.

Patented Jan. 10, 1922.

2 SHEETS-SHEET l.

H. L. ZABRISKIE. CENTRIFUGAL SWITCH.

APPLICATION man APR. 19. 1920.

Pateqted Jan. 10, 1922.

2 SHEETS-SHEET 2r Zag:

UNITED STATES PATENT oFFlcE.

' HENRY L. ZYABRISKIE, OF WESTFIELD, NEW JERSEYnASSIGNOR TO DIEHL MANUFAC- TURING C0., F ELIZABETH, NEW JERSEY, A CORPORATION 0F NEW JERSEY. I

CENTRIFUGAL SWITCH.

Specification of Letters Patent.

Patented Jan. 10, 1922.

` To all lwhom t may concern.'

-Be it known'that I, HENRY L. ZABRISKIE, a citizen of the United States, residing at Westfield, in the county of Union and State of New Jersey, have invented new and useful -Improvements in Centrifugal Switches, of which the following is a specification.

This invention relates to a centrifugal switch.

An alternating current motor of the single phase, -induction type has a stator ordinarily provided with two windings, one of which is a main or running windin and the other an auxiliary or starting winding. When starting the motor both windings are in circuit with a source of current supply, but when the motor acquires a predetermined speed the starting winding is automatically cut out leaving only the running winding in circuit.

A centrifugal switch embodying this invention is particularly applicable for automatically opening the starting winding when the motor ac uires a predetermined speed, although not limited to such use.

One of the objects of this invention is to provide a centrifugal switch of long life.

Another object is to provide a centrifugal switch in which the arcing or sparking at the contacts upon the opening thereof is reduced.

Another object is to provide a simple, com act and durable centrifugal switch, whic is reliable in operation.

Another object is to provide a centrifugal switch which map be economically manufactured and rea ily and easily assembled.

@ther objects and advantages will hereinafter appear.

An embodiment of the invention is illustrated in the accompanying drawings; wherein:

IFigure 1 is a vertical section through the switch and-associated parts of the motor;

Figure 2 is a front elevation of the centrifugal switch. Y i

Figure 3 is a vertical section on line 3 3 of Fig. 2;

F ig. 4 is a transverse section on line 4--4 of Fig. 2;

Fig. 5 is a perspective of one of the contact levers;

Fig. 6 is a perspective of one of the connector straps;

Fig. 7 is a perspective of one of the brush retaining levers; and

Fig. 8 is a perspective of one of the brush holder brackets,

Figure 1 will be described first.

The motor has an inductor armature or rotor 10 supported by a shaft l1 journalled in any well known manner in the motor casing of which only one end bracket 12 is shown.

An insulating ring 13 surrounds the shaft 11, being spaced therefrom and supported by the end bracket 12. The insulating ring carries two contact orcollector rings 14 and 15 secured thereto in any suitable manner, such, for example, as being embedded therein. These contact rings 14 separated by an insulating ring 16 also embedded in the ring 13.

The contact rings 14 and 15 may be connected with the starting orv auxiliary winding of the motor, so that when the circuit is completed betweenv the contact rings, .the starting winding is connected with the source of current supply from which the motor is operated.

The centrifugal switch is adapted to cornplete the circuit between the contact rings 14 and 15. This switch has a base 17 of insulating material having an opening 17. The switch base 17 surrounds the contact carrying ring 13, and is secured to the rotor 10 by means of screws 18 and held in spaced relation thereto by spacing collars 19. The switch base 17 is so positioned that Contact brushes 22 and 23 carried-thereby are held in cooperating relation to the contact rings 14 and 15 respectively.

These contact brushes 22 and 23 which are preferably of carbon are held in proper` position on opposite sides of the switch base 17 by means of the respective brush vholder brackets 20 and 21 fastened to the base by' rivets or other fastening means.

'As shown in Fig. 2, the circuit between the contact brushes. 22 and 23 is adapted to be completed by two parallel paths, one of .which includes a brush retaining lever 24,

a rivet 25, a connector` strap 26, a rivet 27,

a contact lever 26 and a contact pin 29 carried tlviereby,- while the other path includes a brush retaining lever 24, a rivet 259 a connector strae 26', a rivet 27', a contact lever 28 an a contact pin 29 carried thereby.

and 15 may be Y The brush retaining lever 24 is pivotally mounted onone end of the rivet 25 which extends through the base 17, and is adapted the position shown in Fig. 2 by means ofV the coiled sprin 30 positioned in a Agroove 32 in the base 1 One end of this spring is fastened to the periphery of an aperture 24al in the retaining lever 24, and the other end to an a-rm 28a of the contact lever 28. The arm 28a extends fro-m the back to the front of the base 17 through an opening 31 therein. Under influence of the tension of spring 30, the lateral finger 24b of the brush retaining lever 24 is normally maintained against the end of the contact brush 23 which is consequently maintainedv 1n engagement with the contact ring 15.4 Under the same iniuence the contact pin 29, which may be of copper or other suitable material, Vcarried by the Contact lever 28 is normally maintained in engagement with one end of the contact brush 22.

The brush retaining lever 24 is pivotally mounted on one end of the rivet 25 which extends through the base 17, and is adapted to maintain the contact brush 22 in engagement with the contact ring 15. The contact 32 in the base. One end of this spring is lever 28 is pivotally mounted on the rivet 27 which also extends through the base 17. The rivets 25 and 27 are interconnected by the connector 26,. The brush retaining lever 24 is positioned back of the base 17, while the connector strap 26 and the contact lever 28y are positioned in front thereof.

The brush retaining lever 24 and the contact lever 28 are normally maintained in the position shown in Fig. 2 by -means of the coiled spring 30', positioned in a groove fastened to the periphery of an aperture 24"1 in-the retaining lever 24, and the other end to an arm 28a of the contact lever 28. The arm 28a extends from the front to the back of the base 17 through an opening 31 lever 28 is normally maintained in engagement with one end of the contact brush 23.v

Fig. v5 shows the construction of the contact lever 28 which is provided with a projecting finger 28a bent at right angles thereto. The contact lever 28 is'similar to the lever 28 and differs therefrom merely in thatthe linger 28a is bent to project in the opposite direction and the contact pin 29 carried thereby extends in the same direction as the finger 28a.

Figure 6 shows one of the connector straps by which the rivets 25 and 27, and 25 and 27 are interconnected. i Both 'connector straps 26 and 26 are of the same construction.

Figure 7 shows the construction of the brush retaining lever 24 which is provided with a finger 24b bent at right angles thereto for engaging the end of the contact brush 23, and with a hole 24a adapted to be engaged by one end of the Icoiled spring 30.

and 29 in engagement with the carbon A brushes 22 and 23 and maintain the free ends 24b and 24b of the brush retaining levers 24 and 24 against the ends of the respective brushes whereby the brushes themselves are maintained in Contact with the contact rings 14 and' 15. Thus when the applied centrifugal force is below a, predetermined value, the springs prevent the pivoted contact carrying levers or contactors from moving out of engagement with the contact brushes. Y e

When the motor reaches a predetermined speed the applied centrifugal force is sulficient to overcome the tension of the springs- 30 and 30 .whereupon the contact levers rapidly move outwardly about their pivot points; thus the contact pins 29 and 29 are moved out of engagement with the respective carbon brushes 22 and 23. Consequently the parallel circuits between the brushes fareopened and the starting winding of the motor is cut out leaving only the main or runnmg winding in circuit. The,

fingers or projections 28a and 28a extending through the openings 31 and 31 in the base 17 strike against the walls thereof when the contact levers 28 and 28 move outwardly due to centrifuga-l action.- Thus the outward movement of the contact levers is limited as shown in dotted lines in Fig. 2. When the contact levers 28 and 28 move outwardly, the tension ofthe springs is thereby increased and this increased tension, when the motor is running above the predetermined speed, assists in maintaining the pivoted brush retaining levers 24 and 24 in engagement with the respective carbon brushes; consequently the brushes, themselves, are continually in contact with the contact rings 18 and-19 while the motor is' running. Therefore such sparking or arcing which takes place upon opening of the circuit between the brushes occurs between the contact pins and the brushes. Due to the character of the contacts at which the circuit is broken and the manner in which these contacts are caused to disengage, the sparking or arcing thereat is reduced to a minimum.

Certain advantages are obtained by using duplicate sets of contact arms between the carbon brushes. These advantages are:

l. More perfect balance of the switch;

2. Decreased internal resistance thereof; and

3. Protection against possible failure `of one set of contact arms to function properly.

It is to be understood, however,-that the switch is operative when but one set `of contact arms between the carbon brushes is employed. A switch so constructed will function to hold the starting. winding in circuit when the motor is running below a predeter- /mined speed and to cut this winding out of circuit when the motor reaches the predetermined speed.

It has been observed in many tests with this centrifugal switch that the only appreciable wear is at the carbon contact brushes which are gradually eaten away by the arcing between the brushes and the contact pins. These brushes, however, are easily removable and when worn away may be readily replaced.

yWhile the motor is not running, the contact brushes may be readily removed from the brackets after the retaining levers have been moved about their pivots and away from the brushes. After inserting new brushes in the brush holding brackets the retaining levers may be moved into their normal positions.

Since the removable contact brushes are the only parts of the described centrifugal switch which are subject to any appreciable wear, it will be evident that this switch has a very long life.

The invention contained herein is of course susceptible of other embodiments and adaptations.

What is claim-ed is:

1. An electric switch comprising a rotatable support coacting contactors of b different materials, one contactor being removanly carried by the support and the other pivoted thereon, sc as 'to be moved out of engagement with the removable contactor by centrifugal force, means for preventing separation of the contactors until a predetermined centrifugal force is applied, and means controlled by the pivoted contactor for retaining the removable contactor in position after the pivoted contactor has been moved out of engagement therewith.

2. An electric switch having in combination a rotatable support, two coacting contactors, one being removably' carried by the support and the other pivoted thereon, the pivoted contactor being adapted to be moved out of engagement with the other by centrifugal force, means for preventing separation of the contactors until a predetermined centrifugal force is applied, and means for retaining the removable contactor in position after the pivoted contactor has been moved out of lengagement therewith.

8. An electric switch having in combination a rotatable support, two sets of contactors, each set comprising two coacting contactors adapted to be separated by centrifugal force, one contactor of each set being removably carried by the support and the other pivoted thereon, and means for preventing separation of the coacting contactors until a predetermined centrifugal force is applied and for retaining the removable contactors in position after the pivoted contactors have been moved out of engagement therewith.

4. An electric switch having in combination a rotatable support, two sets of contactors, each set comprising two coacting contactors adapted to be separated by centrifugal force, one contactor of each set being removably carried by the support and the other pivoted thereon, tension means for preventing the separation of the coacting contactors of each set until a predetermined centrifugal force is applied, and levers pivoted on the support and governed by the tension means, the removable contactors in position after the pivoted contactors have been moved out of engagement therewith.

5. An electric switch having Vin combination a rotatable support, two coacting contactors, one being removably carried by the support and the other pivoted thereon, the pivoted contactor being adapted to be moved out of engagement with the other by centrifugal force, tensioning means for preventing separation of the contactors until a predetermined centrifugal force is applied, and means including a lever pivoted on the support for retaining the removable contactor in position after thel pivoted contactor has een moved out of engagement therewith.

6. An electric switch comprising a rotatable base, two coacting contactors, one being supported by the base and the other pivoted the pivoted levers retaining i thereon, the pivoted contactoradapted to be moved out .of engagement with the other contactor by centrifugal force, tensioning means for preventing separation of the contactors until a predetermined centrifugal force is applied, and means, including said tensioning means and a lever pivoted on the base, .for retaining the removable contactor in position after the pivoted contactor has been moved out of engagement therewith.

7. A centrifugal switch for use with a motor having two collector rings, comprising a rotatable support, two `removable contact brushes carried by the support and adapted to engage the -respective 'collector rings, a

contactor pivoted on the support, means normally maintaining the contactor in engagement with one contact brush and preventing the separation thereof until a predetermined centrifugal force is applied, and a pivoted lever in electrical contact with the contactor and maintained in engagement with the other contact brush under influenceA of said means.

8. A centrifugal switch for use with a motor having two collector rings, comprising a rotatable support, two removable contact brushes carried by the support and adapted to engage the respective collector rings, a contactor'pivoted on the support, a spring normally maintaining the contactor in engagement with one contact brush and preventing the separation thereof until a predetermined centrifugal force is applied, and a. pivoted lever in electrical contact with the contactor and maintained in engagement with the other contact brush by said spring.

In Witness whereof, I have hereunto subscribed my name in the presence of two witnesses.

HENRY L. ZABRISKIE. Witnesses:

LEO E. RYAN, L. P. Woon.

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