US2334538A - Operating mechanism for discharge lamps - Google Patents

Description

NOV. 16, 1943. BRYANT 2,334,538

OPERATING MECHANISM FOR DISCHARGE LAMPS Filed Feb. 26, 1942 2 Sheets-Sheet 1 Fig].

Fr-anK D Bryant,

55 His Attorney.

Nov. 16, 1943. F. D. BRYANT OPERATING MECHANISM FOR DISCHARGE LAM PS 2 Sheets-Sheet 2 Filed Feb. 26, 1942 lo 7 6 u "I? yarnt,

r w L? m Bum n His Patented Nov. 16, 1943v 2,334,538 DPEIIIA'IING MECHANISM FOR DISCHARGE LAMPS Frank D. Bryant, Stratford, Coma, assignor to General Electric Company, a corporation of New York Application February 26, 1942, Serial No. 432,882

- 11 Claims.

My invention relates .to an operating mechanism for discharge lamps more particularly flucrescent lamps of the type now in commercial use.-

It is an object of my inventionto provide a new and improved operating mechanism for fluorescent lamps in which manually operable switch 7 means is employed to start the lamp.

It is another object of my invention to provide an improved operating mechanism more particu larly adapted for use with a plurality of fluorescent lamps connected together in circuit.

A further object of my invention is the provision of a new and improved switch mechanism for use with a plurality of fluorescent lamps which comprises relatively few parts and which I may be manufactured at low cost.

In the accompanying drawings, Fig. 1 is a side view' of a switch constructed in accordance with my invention; Fig. 2 is a sectional view through the switch; 'Fig. 3 is another sectional view taken along the line 3-3 of Fig. 1; Fig. 4 is still another sectional view taken along the line 4-4 of Fig. 1; Fig. 5 is a perspective view of the operating handle; Fig. 6 is an exploded view of the switch; and Fig. '7 is a diagrammatic view showing one manner of connecting the switch in circuit with a plurality of fluorescent lamps. Fig. 8 is a view of another circuit arrangement.

Tubular discharge lamps, such as fluorescent lamps, of the type now on the market are provided with filaments at each end of a glass envelope which are heated to a point at which they become emissive so that an arc may be struck be-' tween the filaments lighting the lamp. Switch means must be provided for passing current through the filaments for a predetermined period of time to heat them to a point at which they become emissive after which the current is interrupted causing an arc to strike across the electrodes lighting the lamp. It is to a switch of this type that my invention relates.

-Referring to the drawings, my switch comprises a base ill of insulating material, such as a molded plastic provided with a U-shaped'mounting strap I l fastened to the baseby any suitable means such as the screws l2. 0n the mounting strap between the arms of the U is a threaded nipple or nozzle It for mounting the strap'in an opening in a lamp fixture, or the like. The nipple is adapted to be held in assembled position by a plurality of lock nuts l4. The. baseis provided with a recess ii for housing a portion of the switch operating mechanism now to be described.

In the center of the recess I! and preferably molded integrally with the base I0 is an upstanding boss It. The boss is formedwith a plurality of inclined cam surfaces l'l separated by abutment faces It. In the construction shown, four of these cam surfaces are provided. Extending outwardly from the boss l6 to opposite side walls of the recess I! are ledges IS on which rest contact members 20 and 2|. Each contact member is formed with an inclined cam or contact surface 22 which corresponds to the configurations of the cam surface II. In seated position, the contact surfaces 22 rest on the inclined cam surfaces ll of the boss and the contact surfaces are arranged on opposite sides of the boss so that the two contact surfaces are separated by an adjoining insulating cam surface I'l. Conductors 23 and 24 are fastened to the contacts 20 and 2|, respectively, in any suitable manner as by solder 25. The conductors rest in grooves 28 formed in opposite sides of the ase. I I Cooperating with the contact surfaces 22 is a rotatable conducting'or shorting member 21 provided withdownwardly extending inclined contact arms 28. A centralbearing portion 29 supports the member for rotation on a bearing surface 30 forming part of the base IS. The contact arms are adapted alternately to engage the opposite insulating cam surfaces II or the contact surfaces 22; in the latter instance, a ctr;- cuit is established between the conductors 23 and 24 across theshorting member. The member 21 is made of resilient material, for example, spring bronze, so that the arms move over the inclined.-.

surfaces l1 and drop off the abutment surfaces It with a snap action.

The means for rotating the shorting member 21 includes a spiral drive pin 3| which has a tang 32 seated in a slot 33 formed in the bearing portion 29 of the shorting member. The slot and tang are given any desired cross-sectional shape such that they closely interiit so that the drive pin and shorting member rotate together. I

A portion of the tang extends beyond the shorting member into a recess 34 in the boss l8 to form, in effect, a bearing arbor for the shorting member.

Th spiral drive pin comprises a rectangular piece of metal twisted to shape and is seated in opening ll is punched in a metallic cam member 31 which, in turn, is fastened to the disk 38 by bent-over ears in (Fig. 2). The contact disk is formed of insulating material, preferably sheet contact members I! and 40. The members II and.

40 are secured to the disk in any suitable manner as by bent-over ears 4i. the contact disk 36 is maintained spaced from the shorting member 21 by a spring 42 which surrounds the drive pin 3|, in the manner shown by Fig. 2.

The contact disk 36 is moved vertically along the spiral drive pin by a handle 43 which acts as a push button operating member for the switch. The handle is provided with a hollow extended 'portion 44 which projects through an opening 45 in the mounting nipple It to a position to be operated manually. In order to prevent rotation of the handle, the extending portion 44 is made polygonal in shape and an opening 46 in the mounting strap is similarly formed. This arrangement provides for free sliding movement of the handle in the nipple It. The handle is also formed with an enlarged head orbearing portion 4'! which cooperates with the contact disk 36.

To this end, the head is provided with a recess 48 of a size to receive the cam member 21 and the interior wall of the recess is formed with a plurality of cam surfaces 49 which cooperate with cam surfaces 50 punched out of the surface of the cam member 31; The arrangement of the cooperating cam surfaces is such that rotation of the contact disk 38 in a clockwise direction,

' as viewed in Fig. 6, is prevented while rotation in a counterclockwise direction is permitted. The handle is normally biased to a position at which the head 41 rests against the strap-ll by a spring 5| which rests on top of the spiral drive pin it and extends up into the hollow handle 44.

A tongue 52 formed on the upper end of the drive pin extends up into the convolutions or the spring 5| and maintains it in seated position on the pin, as shown by Fig. 2. The head 41 is formed with a smooth bearing surface 53 at the point where it engages the contact disk 38 so that the contact disk is free to rotate relative to the handle without undue friction. I

Cooperating with the contact members I! and 40 on the rotatable disk are stationary contact members mounted on the base II and which extend into the recess l5. Stationary contact members 54 and 55 form a pair of contacts, adapted to be spanned by one of the arcuate contacts I! and 40 while contact members 58 and 51 form another pair likewise adapted to be spanned by the other one of the contacts 39 and 40. The stationary contacts are secured to the base in any suitable manner as by screws a. The movable arcuate contact members 22 and 4| are adapted to. engage the respective pairs of fixed contacts alternately in a manner now to be described.

Let it be assumed that the switch is in the position shown by Fig. 2 of the drawings with In assembled position,

- the contact arms 22 of the shorting member 21 resting on the inclined cam surfaces I] of the in- 'sulating boss it so that the circuit across the conductors 23 and 24 is open. when the operating handle .44 is depressed, the contact disk 28 is moved downwardly against the action or the spring 42. However, the contact disk I cannot rotate along the length oi? the spiral drive pin ll because the cam surfaces 4| on the enlarsed end oi? the handle engage the corresponding cam surfaces II on the contact disk to prevent rotation of the disk in a clockwise direction. Consequently, continued downward movement ofthe contact disk." will cause the spiral ass-seas drive pin 3| to rotate in a counterclockwise direction, as viewed in Fig. 6, to move the shortin member 21 through an angle of approximately 90 so that the contact arms 28 snap oi! the ledges is into engagement with the fixed contacts 22. This closes the circuit through the conductors 23 and 24.

At the point at which the contact arms 28 snap over the abutmentsuri'ac'es II, the contact disk 36 is depressed to a position such that the arcuate contact members II and 4. span the pairs of fixed contacts 54-" and "-51, respectively, so that a circuit is completed between the individual contacts of each pair. This circuit is maintained as long as the handle 44 is held in a depressed position. As will be described more fully hereafter, the length of time during which the circuit through the fixed contacts is closed determines the time during which a heating current is applied to the electrodes of the associated fluorescent lamps.

Upon release of the operating member 44, the spring 42 will urge the contact disk 36 upwardly, thereby moving the contacts 39 and 40 out of engagement with the corresponding pairs of fixed contacts and opening the circuit through these contacts. During upward movement of the contact disk, the drive pin 3| cannot rotate in a clockwise direction, as viewed in Fig. 6, because the contact arms 28 of the shorting member engage the abutment faces it; this means that the drive pin 3| is held in fixed position so that as the contact disk 38 is moved upwardly by action of the spring 42, it will be rotated in a counterclockwise direction along the length of the spiral drive pin through an angle of approximately 90 to move the arcuate contacts 39 and 40 out of alignment with the fixed contacts 54-55 and 565I. Accordingly,jthe next time the operating member 44 is depressed the arcuate contact members I! and 40 which have been moved out of alignment with the fixed contacts will not make contact therewith as the disk 36 is depressed so that only the insulating portion of the ment with the fixed contacts 22 into seated position on the insulating cam surfaces ll, thereby opening the circuitbetween conductors 23 and 24. The manner in which my switchis connected in circuit for operating a plurality of fluorescent lamps will now'be described.

Referring to Fig. 7, I have rescent lamps N and ii operatively connected in circuit with my switch and with a ballast B of a type commercially available. The ballast is provided with a reactor l2 having a lagging power factor connected to lamp 6| while a second reactor 62, having a leading power factor, by reason of the capacitor 04 is connected to the other lamp 0|; a compensator in the form of a reactor adds inductance to the heating circuit of the second lamp to insure quick starting. As mentioned above, this is an example of a ballast of the type available on the market and forms .now be described it being noted that in the diagrammatic showing oi Fig. 7 the switch is -in fon" shown two fluoposition with the arcuate contacts 29 and It in engagement with the fixed contacts.

When the switch handle 44 has been depressed to a starting position, the circuit through the shorting member 21 across the contacts 22 will be closed. Current thus flows from one side I9 oi an ballast. In those cases where the fluorescent lamps 69 and ii are of the inch, 14 watt type, the ballast L is a lamp rated at 60 volts, .5 ampere. Assuming that the switch mechanism has been depressed to starting position, the starting 'circult for the lamps shown in Fig. 8 operates as follows:

Current from supply line 19 fiows to filament 66, through conductor 12 to fixed contact 54, arcuate contact 99, fixed contact 55, conductor p 13 to the filament 61 at the other end of the ductor 23 to the other side H of the alternating current supply. Simultaneously, current fiows from the reactor 69 through a conductor ll to the filament 69 of the other fluorescent lamp 6|, then .by conductor 18 to the fixed contact 51 of the other pair of contacts through arcuate contact All tofixed contact 56, then by line'li to the compensating reactor 69- by the conductor 11 to the other filament 99 and then through con-,

ductor I9, conductor 24, fixed contact 22,- shorting'member 21, the other contact 22, conductor 22 to the other side H of the line.

It will be apparent that the arrangement is such that as long as the switch is held in depressed position, current will fiow through the electrodes of both fluorescent lamps to preheat them. Usually, this preheating time is of the order of one to five seconds. After that time the operating handle 44 is released so that the armate contacts 39 and 49 are moved out of engage ment with the fixed contacts 54-55 and 58-9l. This opens the circuit across the filaments of the lamps so that the reactors 62 and 83 provide an inductive kick causing a glow discharge to strike between the electrodes of each lamp, lighting the lamps. When this occurs, the circuit through the operatingmechani'sm is as follows.

Current fiows from reactor 93 through line H to filament 66 across the glow discharge through the lamp to to filament 61, line 2|, shorting member 21 to the other side of the supply line. Simultaneously, current fiows from reactor 83 by line 15 to filament 69, then' across the glow dis-.- charge in lamp 6| to the other filament 68 through conductor 19 to shorting member 21 to the other side of the line.

When it is desired to turn'oll' the lamps, the plunger 44 is again depressed, thereby moving the shorting member 21 out of engagement with the fixed contacts 22, interrupting the circuit through the lamps. This time, however, the arcuate contacts 39 and 40 do not mate with'the fixed contacts'because they have been rotated out of alignment with the contacts through an arc of 90 when the plunger was released to start the lamps. After the lamps have been turned oil, they may again be turned on simply by depressing the plunger 44 so that the arcuate contacts 39 and 49 again engage the fixed contacts and the shorting member spans the contacts 22.

My switch may be used in other operating circuits, for example, an arrangement such as that shown by Patent 2,266,619, issued to John H. Campbell on December 16, 1941, and assigned to the same assignee as the instant application.

' This arrangement is shown by Fig. 8 or the drawings. In this operatingcircuit, the reactor ballast B, used in the circuit of Fig. 7, is replaced 'lamp, then through a conductor 80 to filament 89 of the other lamp, conductor 16, fixed contact 51, arcuate contact 40, fixed contact 56, conductor 9 l to the filament 69 at the other end of the lamp, thence through conductor 82, fixed contact 22, shorting member 21, conductor 23, lamp ballast L to. the other side 14 oi'the supply line. It will thus be apparent that current fiows through all the filaments of both lamps in series and likewise through the ballastlamp L,

I The switch'mechanism is held in depressed position for a suitable time interval, on the order of one to five seconds, until the lamp filaments are sufilciently heated. Upon release of the switch mechanism, the circuit through the pairs of fixed contacts 5455 and 56-51 is interrupted causing a glow discharge to strike between the filaments lighting the lamps. When this occurs, current. flows from one side 19 of the supply line to the filament 66 across the glow discharge in lamp 69 to the other filament 61, then through the conductor 80 to filament 69 or the other lamp across the glow discharge of this lamp to the filament 69, then through conductor-92, shorting member 21, lamp ballast L to the other side 14 of the supply line. the lamps 86 and GI are still electrically connected in series with the lamp ballast L. The circuit arrangement of Fig. 8 is particularly.

' adapted for use with direct current although it with a lamp ballast L and the lamps are conthe when the first switch is opened, full line voltage is applied to one of the lamps, causing a glow discharge to take place which, due to the negative resistance coefilcient or the lamp, permits a surge of current thereby raising the temperature of the filaments of the other lamp, efiectively reducing its starting voltage so that when the switch or the other lamp opens, the lamp will light. It is only necessary that the switches open in succession a fraction of a second apart.

In my switch construction, the successive operation of the switches rormed by th arcuate contacts 39 and 49 is attained by virtue of manuiacturing tolerances. Thes normally are such that it'would be almost impossible to secure an absolute simultaneous opening of the circuits through the arcuate contacts 39 and 40. One

,0! the contacts will always open slightly ahead 01' the other so that the circuit across the filaments or the various lamps will be opened in succession in the manner described in the Camp bell patent. t r V While I have illustrated my switch as being used with two fluorescent lamp in various operating circuits, it should be manifest that the In lighted position,

conducting member:

switch will operate equally as well with only a single fluorescent lamp simply by omitting the connections to one of the pairs of contacts 54 or 58-51. Similarly, it would be possible to control the operation or mor than two fluorescent lamps by providing an additional pair of contacts and by so designing the spiral drive pin that the contact carrying disk 36 would be rotated through an angle sufilcient to movp the contacts out of alignment with the fixed contacts on the base when the switch is operated to turn of! the lamps.

What I claim as new and desire'to secure by Letters Patent oi! the United States is:

1. In a switch mechanism, a base of insulatin material, spaced fixed contacts mounted on said base, a shorting member rotatably mounted on said base for closing the circuit between said contacts', a spiral drive pin for rotating said shortv ing member, a disk mounted for movement along the length oif said drive pin, said disk carrying spaced contact bars, a plurality of pairs of con tact members carried by said base, each contact bar cooperating with a respective pair 01 contact members to close the circuit between in dividual contacts oi? each pair, a spring surrounding said drive pin and normally maintaining said contact disk spaced from said pairs of contact members, and a depressible plunger engaging said contact disk tolmove it downwardly into engagement with the pairs or contact members and simultaneously rotate said shorting member.

2. In a, switch mechanism, a base of insulatins material, spaced contacts mounted on said base, a conducting member rotatably mounted on said base for closing the circuit between said contacts, a spiral drive pin for rotating said conducting member, a disk mounted for movement along the length of said drive pin, said disk carrying a contact .bar, a pair of contact members carried by said base, the contact bar cooperating with the pair of contact members to close the circuit between the individual contacts of the said pair, spring means normally maintaining said contact disk spaced from said pair of contact members, and a plunger engaging said contact disk to move it downwardly into engagement with the pairs of contact members and simultaneously rotate said conducting member.

3. In a swi mechanism, a base of insulating material spaced contacts mounted on said base, a conducting member rotatably mounted on said base for controlling the circuit between said contacts, aspiral drive pin for rotating said conducting member, a disk mounted for move- I ment along the length or said drive pin, said disk carrying a contact bar, a pair of contact meme bers carried by said base for cooperation with said contact bar, spring means normally main taining said contact disk out of engagement with said pair of contact members, a depressible plunger, and interengaging cam means on said contact disk and plunger to prevent rotation oi! said disk as the disk is moved downwardly into engagement with the pair of contact members whereby said drivepin is rotated to operate said 4. In a device of the class described, a base of insulating material, switch mechanism carried by said base including a rotatable circuit controller, a spiral drive pin for rotating said circuit controller, a member movable along the length of said drive pin, additional switch member, and manually operable means engaging said member to move it along the length of said drive pin to operate'said last-mentioned additional switch mechanism, movement of said member along said drive pin causing the latter to rotate to operate said rotatable circuit controller.

5. In a device of the class described, a base of insulating material, switch mechanism carried by said base including a rotatable circuit controller, a spiral drive pin for rotating said circuit controller, a member movable along the length oi! said drive pin, additional switch mechanism carried by said base and being operable by said member, manually operable means, interengaging cam means on said manually operable means and said member to prevent rotation of said member as it is moved along the length of said drive pin to operate said last-mentioned additional switch mechanism whereby said drive pin rotates said circuit controller and spring means biasing said member to initial position by moving it rotatably along the length of said spiral drive pin.

6. In a device of the class described, a base oi insulating material, switch mechanism carried by said base including a rotatable circuit controller, a spiral drive pin for rotating said circuit controller, a member movable along the length moved along the length or said drive pin by movement of said plunger to operate said lastmentioned additional switch mechanism whereby said drive pin is rotated to operate said circuit controller.

7. Ina device of the class described, a base of insulating material, switch mechanism carried by said base including a rotatable circuit controller, a spiral drive pin for rotating said circuit controller, a member movable along the length of said drive pin, said member carrying a conducting element, contacts carried by said base cooperating with said conducting element as said member is moved along said drive pin, a nonrotatably mounted movable plunger and interengaging cam means on said plunger and member to prevent rotation of said member as it is moved along the lengthof said drive pin by movement of said plunger to place said conducting element incontact with the contacts on said base whereby said drive pinis rotated to operate said circuit controller.

8. In a device oi. the class described, a base oi! insulating material, switch mechanism carried by said base includinga rotatable circuit controller, a spiral drive pin for rotating said circuit controller, a member movable along the length of said drive pin, spaced contacts carried by said base, said memberv carrying a conducting element normally in alignment with said contacts, a nonrotatably mounted plunger, interengaging cam means on said plunger and member toprevent rotation of said member as it is moved along the length of said drive pin by movement of said plunger to place said conducting element in contact with said spaced contacts whereby said drive pin is rotated to operate mechanism carried by said base operable by said 5 tatably along the length of said spiral drive pin to position said conducting element out of alignment with said spaced contacts.

9. In a device of the class described, a base of insulating material, switch mechanism carried by said base including a' rotatable circuit controller, separate spaced contacts carried by-said base, a member having a conducting element normally spaced from said contacts, manually the conducting element in engagement with said spaced contacts, and means operative upon movetact-s, and means operated by movement of said troller, a spiral drive pin for rotating said ciroperable means for moving said member to place a ment of said member for rotating said circuit controller.

10. In a device of the class described, a base oi insulating material, switch mechanism carried by said base including a rotatable circuit controller, separate spaced contacts carried by said base, a member having a conducting element, means normally biasing said member to maimtain said conducting element out of electrical engagement with said contacts, a plunger for moving said member against the action of said biasing means to place the conducting ,glement in electrical engagement with said spaced cone cult controller, a member movable along the length of said drive pin, separate spaced contacts carried by said base, said member carrying a conducting element normally in alignment with said spaced contacts, spring means normally maintaining said conducting element out of engagement with said spaced contacts, a non-rotatably mounted plunger and interengaging cam means on said member and plunger to'prevent rotation of said member as the latter is moved along the length of said drive pin to place said conducting element in engagement with said spaced contacts whereby said drive pin is rotated to operate said circuit controller, said biasing means being adapted to return said member to initial position by rotation along the length of said spiral drive pin.

FRANK D. BRYANT.

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