US3303301A - Rotatably selectable high voltage switch - Google Patents

Description

Feb. 7, 1967 Filed Sept. 30, 1964 L. SCOTT ROTATABLY SELEGTABLE HIGH VOLTAGE SWITCH 5 Sheets-Sheet 1 L EWIS SCOTT ATTORNEY Feb. 7, 1967 L. sco'rT 3,303,301

ROTATABLY SELECTABLE HIGH VOLTAGE SWITCH Filed Sept.v 30, 1964 5 Sheets-Sheet 2 LEWIS SCOTT BY /MM ATTORNEY Feb. 7, 1961 L. SCQTT 3,303,301

ROTATABLY sELEcTABLE HIGH VOLTAGE swITcH Filed sept. 3o, 1964 5 Sheets-Sheet 3 INVENTOR L EW/S S0077'v ATTORNEY Feb. 7, 1967 L. scoTr 3,303,301

' ROTATABLY SELECTABLE HIGH VOLTAGE SWITCH Filed Sept. 50, 1964 5 Sheets-Sheet 4 INVENTOR fw/s scarf ATTORNEY Feb. 7, 1967 L. 5amv 3,303,301l

ROTATABLY SELECTABLE HIGH VOLTAGE SWITCH Filed Sept. 30, 1964 5 Sheets-Sheet 5 m. LIJ [L 0 oo m l LID v MIGROSWITGH g @l INVENTOR Ew/s scarf I U) O 1 BY ,f f'

ATTORNEY United States Patent O 3,303,301 ROTATABLY SELECTABLE HIGH VOLTAGE SWITCH Lewis Scott, Deale, Md., assigner to the United States of America as represented by the Secretary of the Navy Filed Sept. 30, 1964, Ser. No. 400,614 7 Claims. (Cl. 20d-51.1)

The invention described herein may be manufactured and used by or for the Government of the United States of America for governmental purposes without the payment of any royalties thereon or therefor.

AThe present invention relates generally to a switch and more particularly to a mechanical safety switch assembly for switching high current from high voltage capacitors.

In the field of high voltage switches it is the practice to provide either knife type or plug-in type switches which are suitable in certain applications but which are impractical where selection is desired. On the other hand, selectable switches are usually of the rotatable selectable variety which are inadequate for high current-high voltage operations. Although such devices have served their intended purpose, they are not entirely satisfactory for all applications, particularly in high voltage capacitor switching operations where a selectable plug-in type switch is desired which can be manually operated by a single control. Also, in capacitor switching operations, prior art devices have not provided means for shorting the capacitors to insure complete discharge so that operating personnel may safely approach the capacitor unit manually. It has been necessary in high voltage applications for personnel t to place heavy bus bars between the selected capacitors and iiash unit. Also the capacitors had to be shorted before they could be safely handled. This shorting operation in itself has proven highly dangerous where inexperienced personnel are involved.

The general purpose of this invention is to provide a high voltage capacitor switch which embraces all the advantages of prior art devices and which possesses none of the disadvantages described above. To attain this, the present invention contemplates a unique switch assembly for switching high current from high voltage capacitors which is controllable by a single selector knob on the front panel of the system housing. The selector knob is mounted on a main rod to which the male section of the switch is connected. When the knob is pulled completely out, it may be manually rotated to select any of several capacitor values. After selection has been made the knob is pushed forward and the switch is thereby engaged. The main rod has a channel about its periphery for receiving a plunger rod afiixed to a time delay relay. This plunger rod is inserted into the channel thereby locking the switch when system power is turned on and maintains the switch in the locked position until a delay period has elapsed after system power has been turned off. The delay time allows the capacitors to discharge thro-ugh a bleeder network. A shorting means actuated by the main rod is provided which shorts the capacitors when the selector knob is pulled out thereby insuring complete discharge of the capacitors. When the knob is pushed in to engage the switch, the shorting means is removed from its shorting position by the rod before switch contact is made. A groove for receiving a bullet catch is also provided in the main rod. As an added feature, the lid of the system housing is kept locked in its closed position while the switch is engaged by means of a bracket atxed to and extending from the lid so that the main' rod passes through it. Also, system power cannot be applied until the lid is closed and the plunger rod of the time delay relay has entered its receiving channel in the main rod.

3,393,3@l Patented F eb. 7, 1367 ICC The switching assembly herein described has general use for high voltage control applications and is of special use in the high voltage flash control unit described in copending application Serial No. 339,038 of Gordon Stamm and Lewis Scott filed January 20, 1964.

An object of this invention is to provide a new and improved high voltage switch.

Another object is to provide a high voltage switch which .is rotatably selectable when the switch is open.

A further object is the provision of a high voltage `switch which is manually controlled by a single knob.

Still another object is the provision of a high voltage capacitor switch having safety features for insuring that the capacitors are completely discharged before personnel can manually enter for servicing.

Yet another object of the present invention is the 'provision of -a high voltage capacitor switching and housing assembly whereby the switching assembly insures that the housing cannot be opened `until the capacitors are completely discharged.

A still further object of the invention is the provision of a high voltage capacitor switching assembly and housing in which power cannot be applied until the switch is properly engaged and the housing lid is locked.

Other objects and many of the attendant advantages of this invention will be readily appreciated as the same becomes better understood by reference to the following detailed description when considered in connection with the accompanying drawings wherein:

FIG. 1 illustrates a side View of a preferred embodiment of the invention.

FIG. 2 illustrates a side view of an embodiment of the high voltage switching assembly.

FIG. 3 is a front view of a disc employed in the embodiment of FIG. 1.l

FIG. 4 is a front view of a plate employed in the embodiment of FIG. l.

FIG. 5 is a front view of a spring finger unit used in the embodiment of FIG. 1.

FIG. 6 is a front view of a disc used in the embodiment of FIG. 2.

FIG. 7 is a front View of a bodiment of FIG. 2.

FIG. 8(a) is a front view of the spring finger unit used in the embodiment of FIG. 2.

FIG. 8 (b) is side view of one of the spring fingers of the spring finger unit illustrated in FIG. 8(a).

FIG. 9 is a simplified schematic diagram of the switching system.

Referring now to the drawings, wherein like reference characters designate like or corresponding parts through'- out the several Views, there is shown in FIG. 1, which illustrates a preferred embodiment, a system housing 8 containing the high-voltage capacitor switch 16 together with the capacitor assembly 23. A circular glass melamine disc 6 (shown in FIG. 3) is supported directly from the front panel 7 of the ash unit housing 8 by a square Bakelite support 9 `attached to the outer edge of the disc 6. Insulated disc 6 serves as the female section of the switch and supports binding post receptacles 11 of the type which can receive conventional banana plugs 12. Five binding post receptacles 11 spaced approximately 30 apart are located about disc 6, as shown in FIG. 4, and extend therethrough terminating in nuts 13. Mounted directly in the center of the disc 6 and extending perpendicularly therefrom is a circular Bakelite support rod 14 which acts as a guide for rod Z5 supporting male section 15 of switch 16. Rod 14 extends from disc 6 at a diameter approximately equal to the outer diameter of the hollow portion 18 of rod 2S and then continues away from disc 6 toward front panel 7 at a smaller diameter plate employed in the emwhich is slightly less than the inner diameter of the hollow portion 18 of rod 25 thereby forming `a stop for rod 25 when switch 16 is in its fully closed position. Clrcular rod 14 has an aperture through its center for its entire length for receiving rod 19 which is iirmly attached to and concentric with rod 25. Male section 15 of switch 16 comprises an aluminum plate 1`7 (shown in FIG. 4.) supporting five banana plugs 12 any one of which 1s capable of being received by any one of the binding posts 11. Banana plugs 12 are fastened to plate 17 by nuts 39. Since plate 17 is conductive all plugs 12 are connected in common and lead 43, which is. connected to plate 17 by lug 44 under one of the nuts 39, serves as the common output of the switch for conducting capacitor current to the liash assembly 68. The aluminum plate 17 is attached to the end of circular hollow Bakelite portion 18 of rod 25 which slides over the rod 14 in tting engagement therewith. Concentric with the hollow portion 18 of rod 25 is Bakelite rod 19 having a diameter much smaller than that of rod and extending beyond the hollow portion 18 through the aperture in the center of support 'rod 14, through the aperture in the center Iof disc 6, through an aperture in bottom bracket 21, through an aperture in top bracket 22, and through an aperture in the front panel 38 of capacitor housing 23, to disengage all of the spring fingers 24 from their resting position before the switch is fully engaged. Bottom bracket 21, lid bracket 22, and panel 38 all have their apertures axially aligned so that rod 19 passes therethrough to disengage the spring fingers 24.

The hollow portion 18 of rod 25 has a yshallow groove 26 about its periphery for receiving bullet catch 27 located within the support 9. Near groove 26 is a channel 28 for receiving plunger rod 29 of relay 31. Rod 25 is of approximately uniform diameter, with the exception of the groove 26 and channel 28, from the hollow end which supports plate 17 back toward the front panel 7 to and including a shoulder forming a limit stop 33. From limit stop 33 a solid portion 34 of rod 25 extends through and beyond the front panel 7 so that a knob 37 can be affixed thereon.

Selector knob 37 has a pointer 35 aiixed thereon. The front panel 7 is engraved with five radial marks spaced 30" apart corresponding to the switch positions and calibrated in accordance Iwith capacitance. The in tensity of the flash provided by ash assembly 68 is proportional to the value of capacitance selected. The desired capacitance is selectedby rotating the selector knob 37 so that the dial pointer 35 is in line with the radial mark on the front panel 7. After selection has been made, the knob is pushed fully forward to engage the switch. i

The square Bakelite support 9 which supports disc 6 has a vertical opening extending completely therethrough for allowing rod 29 of relay 31 to pass through support 9 to channel'28 of rod 25, thereby locking the rod 29 in the position illustrated in FIG, l 'when the relay 31 is energized. Relay 31 is attached to the front panel 7 above the switch 16. It .is a time delay' relay with the delay operation taking place when the relay is deenergized. The relay is a delay-before-break type-double-poledouble-throw relay. 'An Agastat type NE 22 QT relay, which hasa` diaphragm or bellows operated by pressure, was modified by attaching a plunger rod to the diaphragm.

A heated treated rhodium flashed beryllium copper spring finger unit 36 having five extending fingers 24, as shown in FIG. 5', is supported on the inside of the panel 38 of capacitor housing 23. Also supported on the capacitor housing panel 38 and insulated therefrom are ve rhodi um ashed cap nuts which act as capacitor contacts 41 and which are individually connected to their respective capacitor by leads 45. The cap nuts are aligned with a respective one of the spring lingers 24 and are connected to their respective binding post receptacles by means of leads 46 having lugs 48 which fit between nuts 13 .and

disc 6. Leads 46 are passed through a slot in panel 38 and around bottom bracket 21 to the nuts 13. In their unactuated position, that is when rod 19 has not pushed the spring fingers 24, the five spring fingers 24 rest on the rear of the five capacitor contacts 41.

In operation, the selector knob 37 is pulled out :away from the front panel 7 as far as possible, rotated and aligned with the desired radial mark on front panel 7. When the knob is pushed into its full forward position the knob 37 is the same distance from the panel as any other conventional knob control. As the selector 37 is pushed forward, rod 19 travels through bottom bracket 21 and lid bracket 22 and then through the capacitor housing front panel 38 to push the spring fingers 24 away from the capacitor contacts 41. The portion of rod 19 extending beyond disc 6 is of such a length that the spring lingers 24 will be pushed away from their respective contacts 41 before the banana plugs 12 enter their respective binding post receptacles 11. As the selector knob 37 is still driven forward the plugs 12 enter and make contact with the corresponding binding post receptacles 11. With the selector knob 37 driven completely forward the bullet catch 27 enters groove 26 and the switch is ready for flash unit operation. l

With the switch in position, relay 31 will be energized when' power ,is turned on, provided that the lid 44 is on the housing 8. -If lid 44 is not on housing 8 a lid microswitch (shown schematically in lFIG. 9) will be open. Since this 'rnicroswitch is serially connected in the power circuit, relay 31 cannot be energized with the lid off.

When power is turned off, the time delay relay 31 is deenergized and the preset delay starts. During this delay the switch cannot be opened since rod 29 locks the switch in position until the end of the delay time which is set for a period of time suthcient to allow the high-voltage capacitors to adequately discharge. The discharge time constant is determined by the value of capacitance and also the value of bleeder resistance connected to the high-voltage capacitors. At the end of this delay, the switch may be pulled open and the spring fingers 24 return to their resting position on capacitor contacts 41 thereby shorting the capacitors and insuring complete discharge. v

The switchmust be inthe fully closed position (as illustrated in FIG. l) before power may be applied. vIf partially closed, -rod 29 will prevent its associated relay contact (shown schematically in FIG. 9) from closing even if the relay coil is energized, thus any possibility of power 'being applied to the system before the capacitors are in the circuit is eliminated. Rod 19 also prevents the lid 44 of system housing `8 from being opened while the switch is engaged, since the rod passes through an aperture in lid bracket 22. Bottom bracket 21 and panel 38 cooperate to support rod 19 when an attempt is made to remove the lid 44 of housing 8.

For purposes of illustration only a single binding post receptacle 111, banana plug 112, capacitor terminal 41', spring finger 24, lead 46, lead 45 and capacitor has been shown in FIGS. 1 and 2. However, it is understood that five of each of the above components are employed in the embodiments described and illustrated. It is also understood that any reasonable and workable number of such components may be used within the scope of this invention.

FIG. 5 illustrates the spring linger unit 36 employed in the embodiment of FIG. 1 Ihaving `five spring fingers 24. In the preferred embodiment of FIG. l the end 81 of unit 36 opposite the fingers is fastened by any suitable means such as a nut and bolt to panel 38 which is maintained at ground potential. Openings 82 in spring nger unit 36 shown in FIG. 5 provide adequate flexibility when the rod 19 strikes point 83- of the `spring finger unit 36. In PIG. 3 the disc 6 used in the embodiment of FIG.v 1 is illustrated showing locations 62 of the five binding post receptacles 11 (shown in FIG. 1) and aperture 63 for receiving rod 19 (also shown in FIG. 1). FIG. 4 illustrates aluminum .plate 17 used in the embodiment of FIG. 1 in which the banana plug positions 72 are shown together with aperture 73 which passes over rod 14 of FIG. 1.

In FIG. 2 a second embodiment of the invention is illustrated in which the finger stock 36 of FIG. 8 is mounted on the rear of glass melamine disc 6 of FIG. 6. Nuts 13 are replaced by the rhodium flashed cap nuts 41 upon which the spring fingers 24 rest and to which the leads from the capacitor are now directly connected. Disc 6 has apertures for allowing each push rod actuator 51 affixed to aluminum plate 17 (shown in FIG. 7) to remove one of the spring fingers 24 from its resting position on the cap nut 41. There are five push rod actuators, one for each spring finger 24, which actuators are of such length that the spring fingers act-uated will be separated from their respective contacts a distance suficient to prevent an electric arc. The spring finger unit 36 employed in the switch embodiment of FIG. 2 is shown in FIG. 8. FIG. 6 illustrates the disc 6 (used in'the switch embodiment of FIG. 2) having apertures 61 for receiving the push rod actuators 51 and shows the positions 62 of the binding post receptacles 11- FIG. 7 illustrates aluminum plate 17 and shows locations 71 upon which the push rod actuators 51 are affixed as well as locations 72 upon which the banana plugs 12 are positioned. The aluminum plate 17 of FIG. 7 is used in the switch embodiment of FIG. 2. Also used in the switch embodiment of FIG. 2 is the spring finger unit `36 illustrated in FIG. 8(a) having spring fingers 24. The side view of one of the spring fingers 24 illustrated in FIIG. 8(b) shows bend 81 for providing flexibility when the push rod actuators 51 strike point 84 to disengage the spring fingers 24 from their respective capacitor contacts 41.

F'IG. 9 is a simplified schematic diagram of the switching system and shows a portion of disc 6 serving as the female section of switch 16 having receptacles 11 which are connected to capacitor network 23. The male section of switch 16 comprises plate 17 having banana plugs 12 which can be inserted into any of the receptacles 11. Male half 17 is controlled by rod 25 which can be rotated by selector knob 37 when the switch is not engaged. The high voltage from plate 17 is directly connected to flash assembly 68 by lead 43. Relay 31 is energized to actuate plunger rod 29 when power on switch 9.1 is closed and when lid microswitch 92 is closed thereby insuring that the lid is on. If switch 16 is not completely engaged so that rod 29` cannot enter channel 28 of rod 25 then plunger contact 93 will not close thereby prevent-ing application of .power to the system, including the high voltage capacitor section 23 and fiash assembly 68.

Obviously many modifications and variations of the present invention are possible in the light of the above teachings. It is therefore to be understood, that within the scope of the appended claims, the invention may be practiced otherwise than as specifically described.

What is claimed and des-ired to be secured by Letters Patent of the United States is:

1. A switch comprising:

a male section having a plate with a plurality of conductive plfugs mounted thereon,

a female section comprising a stationary circular disc lhaving a plurality of conductive receptacles mounted thereon and aligned for receiving said plugs,

a circular support rod attached to the center of said disc and perpendicular thereto,

a first rod having one end attached to said male section to enable said male section to be rotated and reciprocated into electrical contact with said female section,

said first rod being hollow at the end to which said plate is attached so that said circular support rod fits into said hollow end of said first rod to guide said first rod into a plug and receptacle engaged position, and

means coupled to said disc and said male section for electrically shorting said conductive receptacles when said plugs and receptacles are disengaged.

2. A switch as set forth in claim 1, wherein said means for electrically shorting comprises a plurality of fiexible conductive fingers each for electrically shorting a respective one of said receptacles, and further including:

a first electrical terminal coupled to each of said receptacles on said disc,

a second electrical terminal coupled to said plugs, and

means controlled by said first rod for activating or deactivating said means' for shorting.

3. A switch as set forth in claim 2 wherein said means for activating or deactivating said shorting means comprises a second rod of a diameter which is a fraction of the diameter of said first rod concentrically aligned with and attached to said irst rod, said second rod extending beyond said first rod and thro-ugh an aperture in said disc to activate said shorting means as a unit, whereby all of the fingers of said shorting means are displaced from their shorting position before the switch is closed and as said first rod is pushed forward to engage said switch, and whereby said shorting means is allowed to return to its shorting position across said `receptacles after said switch is opened.

4. A switch as set forth in claim 2 wherein said means for activating or deactivating said shorting means comprises a plurality of actuator rods perpendicularly attached to said plate and radially aligned with said plugs for actuating each of said fingers independently through apertures in the disc.

5. A switching unit comprising:

a housing having a bottom panel, a front panel having an opening therein, a rear panel, two side panels, and a lid having a downwardly extending bracket with aperture therein,

a time delay relay having a .plunger rod attached thereto mounted on said front panel,

means for energizing said time delay relay,

a switch assembly including a plug-in type rotatably selectable switch having a stationary female end and a male end which is rotatable when said switch is open and also movable for engagement with said female end,

means for controlling said male end of saidyswitch eX- tending beyond said front panel of said housing, supporting means for coupling said switch to said front panel,

means in said switch assembly for receiving said plunger rod when said relay is energized, whereby said switch is locked into a closed position, and

means extending from said male end of said switch and passing through the aperture in said lid bracket thereby locking said lid onto said unit while said lswitch is closed.

6. A switching unit as set forth in claim 5 wherein said male end has a plurality of plugs and said female end has a respective receptacle for each of said pl-ugs and wherein said switch assembly further comprises means for electrically shorting the receptacles.

7. A high voltage switching system comprising:

a housing having a bottom panel, a front panel having an opening therein, two side panels and a lid,

a time delay relay having a plunger rod attached thereto mounted on said front panel,

means for energizing said relay,

a switch comprising,

a male section having a conductive plate with a plurality of conductive -plugs mounted thereon, a female section comprising a stationary insulated circular disc having conductive receptacles mounted thereon and aligned for receiving said plugs,

a first rod having one end attached to said rnale section to enable said male section to -be rotated and positioned into electrical contact with said female section, said first vrrod being hollow at the end to which said plate is attached, and said first rod having a channel about its periphery for receiving 4the plunger rod of said time delay rrelay whenv said relay is energized, so that said first rod is locked in position While said plunger rod is in said channel,

l a circular support rod attached .to the center of said disc and perpendicular thereto, said circular support rod fitting into said hollow end of said first rod to guide said first rod so that said switch can be guided into an engaged position,

a first terminal coupled to each of said receptacles on said disc, Y

a second terminal coupled to said plugs,

snorting means, coupled to and behind said disc,

. comprising a plurality of flexible conductive fingers each for electrically contacting a respective .one of said receptacles,

means controlled by said Ifirst rod for activating or deactivating said sho'rting means comprising a second rod of a diameter which is a fraction of the diameter of said first rod, said second lrod extending beyond said first rod and through an supporting means coupled between said front panel and the disc of said switch,

a bracket attached to and extending downwardly from said lid and having an aperture aligned to receive said second rod so that said second rod passes therethrough and maintains said lid in a closed position while said switch is engaged.

References Cited by the Examiner UNITED STATES PATENTS 8/1929 Coats 200-87 X 2,512,880 6/195'0` Russell 20G-4 X 2,594,181 4/1952 Kliegl et al. 2160-4 X 2,608,624 8/ 1952 Goodrich 20 0l2 RGBERT K. SCHAEFER, rimary Examiner.

D. SMITH, JR., Assistant Examiner.

Claims (1)

1. A SWITCH COMPRISING: A MALE SECTION HAVING A PLATE WITH A PLURALITY OF CONDUCTIVE PLUGS MOUNTED THEREON, A FEMALE SECTION COMPRISING A STATIONARY CIRCULAR DISC HAVING A PLURALITY OF CONDUCTIVE RECEPTACLES MOUNTED THEREON AND ALIGNED FOR RECEIVING SAID PLUGS, A CIRCULAR SUPPORT ROD ATTACHED TO THE CENTER OF SAID DISC AND PERPENDICULAR THERETO, A FIRST ROD HAVING ONE END ATTACHED TO SAID MALE SECTION TO ENABLE SAID MALE SECTION TO BE ROTATED AND RECIPROCATED INTO ELECTRICAL CONTACT WITH SAID FEMALE SECTION, SAID FIRST ROD BEING HOLLOW AT THE END TO WHICH SAID PLATE IS ATTACHED SO THAT SAID CIRCULAR SUPPORT ROD FITS INTO SAID HOLLOW END OF SAID FIRST ROD TO GUIDE SAID FIRST ROD INTO A PLUG AND RECEPTACLE ENGAGED POSITION, AND MEANS COUPLED TO SAID DISC AND SAID MALE SECTION FOR ELECTRICALLY SHORTING SAID CONDUCTIVE RECEPTACLES WHEN SAID PLUGS AND RECEPTACLES ARE DISENGAGED.

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