US2743351A - Safety device for electric lamp housing - Google Patents

Description

April 24, 1956 G. GORHAM 2,743,351

SAFETY DEVICE FOR ELECTRIC LAMP HOUSING Filed March 5, 1951 2 Sheets-Sheet l H6. 6. l INIENTOR. 660466 Gaff/4M 92 35 BY 54% M 1- April 24, 1956 SAFETY DEVICE FOR ELECTRIC LAMP HOUSING Filed March 3. 1951 G. GORHAM 2,743,351

2 Sheets-Sheet 2 2,743,351 SAFETY- DEVICE FOR ELECTRIC LAMP HOUSING George Gorham, New York, N. Y., assign-or toScopicon, Iuc., Bronx County, N. Y., a corporation oi New York Application March 3, 1951, Serial No. 213,729 2 Claims. (Cl; 240-2) high voltage to the apparatus upon opening a closure thereof.

The primary object of the present invention is the provision of a generally improved and simplified interlock device which is automatically operable upon the opening of. a closure. to remove'th'esupplyof'voltage to mechanism accessible when theclosure is open.

Another object is the provision ofa simple interlock mechanism which is operable to control the actuation of a plurality-of switches.

A further object is the provision of an interlock mechanism which normally opens the electric circuit when the housing closure is opened but which'can be operated by the electrician under special conditions to complete the, circuit when the closure is opened to obtain access to the interior of the light housing.

The above and other objects, featuresand advantages of the present invention willbe moreiully understood from the following descriptionconsidered in connection withthe accompanying illustrative drawings.

In the drawings:

Fig. 1 is a-perspective view of .a lamphousingand electrical distribution .box thereforembodyiug the present invention, the lamp housing being shown with the closure thereof inv open condition;

Fig. 2. is a sectional viewtaken along.the.line.22 .of Fig. ,1,'the closure being in the closedcondition. thereof;

Fig; 3lis .a sectionalview takenon the line 3-3.of g! Fig. 4-isa detail view illustrating aportion of the switch mechanisminthe open or circuit interrupting condition when the closure. is: opened;-

Fig. 5 is a detail view with the switch mechanism when manually operated to close-the switch when under repair or other special conditions; and

Fig; 6 is a simplified. circuit diagram.

The present inventionis illustrated and described in connection with the. lamp'housingof a'micro-projector of the type disclosed in Patent No.v 2,477,396 to Edwin C.'Weiskopf, datedJuly 26, 194 9, andis primarilyv intended fOT'HSE in connection. with a highvoltage lamp of the-type -used in such projectors.

Referring nowtoFig. 1, there is illustrated a lamp housing Ill) of the typefully illustrated and described in" the aboveridentified patent. Saidv housing. is provided at'the frontthereof with a closure or door. 12 which is 734,585, filed March 14, 1947, now Patent No. 2,569,876, dated October 2, 1951, but which may be a single lamp as illustrated in said first mentioned patent. Water conduits for cooling said lamps are indicated at 20 and 22. The individual lamps 24 and 26 are preferably of the high voltage mercury vapor type and the voltage therefor is supplied by an insulated cable 28 which has a terminal 3i). Cable 23 is of a well known type which comprises connected to a terminal of plug 30 and the sheath which is electrically connected to bracket 27 is electrically connected to a grounded part ofsaid plug. The secondany of an electric transformer is electrically connected to said plug in the manner which will be presently described.

The lamp housing is provided with an electrical dis tribution and control box 32 which may be mounted thereon in any suitable manner, such as for example, by meansof bracket rods indicated'at34. Said distribution box is preferably formed of suitable sheet metal and is provided on the front wall 35-thereof with a low voltage socket 36 for receiving a detachable terminal plug 38 of the supply line 46 which may be connected to any convenient source of alternating current or" ordinary low voltage, preferably 116 volts. A terminal connector block 42 is mounted-in a chamber 44 provided in the front wall of the distribution box 32 above the socket 36. Said terminal block is provided with a set of low voltage terminals 46 and with a set of high voltage terminals 48. Box 32 is also provided with a plurality of low voltage outlet receptacles 5i"! to supply power for operating various auxiliary devices. as in saidPatent No. 2,477,396. It will be understood that all of the low voltage terminals and outlet receptacles or sockets 46 and 5f; are connected in parallel to the input receptacle 35 to which the low voltage plug 33 is connected. More particularly, the low voltage receptacle 36 is provided with the wires 52 and 54 which are electrically connected to the wires 56 and 53, respectively, at the terminals 6% and 62, respectively, of the switchesG-d and 65. it will be understood that the low voltage outlets 5d are connected in parallel to the wires Edand 58. As. here shown, switches 64 and 66 are preferably of the microswitch type, but it will be understood that any other suitable switches may be used. Wires as and '73 connect the switches 6 3 and omrespectively, to the low voltageterminals 46 of the connector block 42 so. that said terminals46. are energ-ized'when said switches are closed and deenergized when said'switches are open. As illustrated and describedin the first mentioned patent, a low voltage distribution line is-used to connect the low voltage terminals eta-or the distributicn'box to the primarywinding P (Fig. 6) ofa step-uptransfcrmer in the power unit of theapparatus iilustt ted and described insaid patent. Asshown in said first mentioned patent, the highvoltage from the secondary S of said transformer is connected to the high voltage terminals 48- ot the distribution box to provide the high voltage required for the lamps 2a. and 26. Referring to Fig. lot the drawings hereof, one of said highvoltage terminals this connected through a wire 72 to a. terminal receptacle or socket 74 in which the previously mentioned: plug is removably received. The other high voltageterminal -48 is connected through a wire 76 to a grotnidingbracket 78 which issecured in any-suitable manner'to the distributiombox 32. Awire 80 extends from said grounding bracket to the receptacle '74 for completing the high voltage supply line to the lamp unit 13. Therefore it will be apparent that the switches are in circuit with the lamp unit. The low voltage receptacle 36 is also connected to said grounding bracket through the wire 82.

Due to the presence of high voltage in the lamp housing 10, safety means are provided to eliminate the danger of personal injury which would be present in case access to the interior of said housing could be obtained when high voltage is connected to the lamp unit 18. For this purpose, and pursuant to the present invention, there is provided a safety device or interlock mechanism which is operable by the closure 12. Said interlock mechanism comprises the'interlock member 84 and the switch actuating parts 86. More particularly, the distribution box 32 is provided with a shelf 87 which extends transversely thereof between the low voltage socket 36 and the terminal block 42. As here shown, said shelf is provided with a depending lateral flange 88 which is secured to the wall 90 of the distribution box in any suitable manner, such as at 92. The shelf is also provided with the bent-up opposing end portions 94 and 96 respectively, which are spaced from the adjacent housing walls 35 and 100, respectively, as illustrated in Fig. 2. Each of said end portions is provided with an aperture 102 through which the interlock member 84 extends.

The micro-switches 64 and 66 are arranged in tandem, said switches being mounted on the upper surface of shelf 87, and each of said switches is provided with a switch operating member 103 which is normally biased to the circuit interrupting or open condition of the switch. Each switch is also provided with a flexible actuating member 86 formed of any suitable spring metal. As illustrated in Fig. 3, one end of the actuating member 86 is secured to the switch and said member extends therefrom as at 104 and overlies the switch operating part 103. The free end 105 of the actuating member is reflexed for a purpose hereinafter described. It will be understood that switches 64 and 66 are normally open switches in that the companion contacts of each switch are automatically separated when the actuator pins 103 are released. Switches of this type are well known and as they do not per se form part of the present invention, further description thereof is unnecessary.

As here shown, the interlock member 84 is in the form of a metallic rod or spindle which is provided with the circumferentially notched portions 106 and 108 disposed in spaced relation longitudinally of said rod. Adjacent the notched portion 108, rod 84 is provided with a portion 110 of reduced diameter to form the circumferential shoulder 112. Said portion 110 is disposed in the aperture 102 and extends through an aperture 98 in the housing wall 100, being provided adjacent the free end thereof with a stop 114. A helical compression spring 115 is provided on said portion 110 between the shoulder 112 and the shelf portion 96. The other end 116 of rod 84 extends through an aperture 118 provided in thehousing wall 35.

It will be noted that the rod 84 is disposed laterally of the switches 64 and 66 adjacent the side thereof on which the actuating member 86 is mounted. The closure 12 is provided with a part 122 which extends laterally therefrom to engage the end 116 of rod 84 when the closure is in the closed position thereof and retains the latter against movement outwardly of the front wall 35. With the closure in the open position thereof, illustrated in Fig. 1, the rod 84 is biased by the spring 115 to the position thereof illustrated in broken line in Fig. 3, in which position the end 116 thereof is moved outwardly of housing wall 35 and the opposing end is moved inwardly relative to housing wall 100. In said position of the rod 84, the recesses or notches 106 and 108 register with the reflex ends 105, respectively, of the companion actuating parts 86. Said parts, being formed of spring metal, reflex bodily so that the reflexed ends 105 thereof engage in the adjacent complementary shaped notched portions, as illustrated in Fig. 4. In this manner, said parts move away from the companion switch operating members 103, permitting the latter to move under their own bias to open the switches. It will be apparent that since said switches are connected in the low voltage circuit to the primary of the high voltage transformer, that in said position of the rod 84, the input to the transformer is interrupted so that there is no high voltage output available from said transformer for the lamp assembly 18. Therefore, in this condition of the apparatus, access may be had to the interior of the lamp housing without danger of injury.

Upon closing the door or closure 12 of the lamp housing, the part 122 carried thereby engages the end 116 of rod 84, as illustrated in Figs. 2 and 3, and moves the latter in the direction of arrow A in Fig. 3, and as illustrated, in the full line position of the parts, so that the notched portions 106 and 108 are moved out of engagement with the reflex ends of the companion actuating parts 86. In this condition, the reflex ends engage the outer surface of the rod 84 and are flexed thereby toward the companion micro-switches to depress the companion operating parts 103 and close said switches. it will be apparent that in this condition of the mechanism, there is a completed low voltage circuit to the primary of the high voltage transformer so that the high voltage is present in the lamp housing for the lamp assembly. Upon subsequent reopening of the closure 12, the rod 84 will be released for movement in the opposite direction, as indicated by the arrow B in Fig. 3, by the compressed spring 105, so that the notched portions 106 and 108 will be in position to be engaged by the reflex ends 105 of the switch actuating parts 86 to interrupt the high voltage supply. It will be noted that this requires only a comparatively small movement of the rod 84 in the direction of arrow B so that the high voltage is discontinued to the lamp housing when the closure 12 has been moved a similar comparatively short distance in the direction of the opening thereof, said latter distance being insufficient to permit the entry of a hand into the lamp housing. Therefore, the high voltage supply is always interrupted before the closure 12 is moved from the housing sufliciently for a person to reach into the interior thereof. Also, it will be understood that since, as above explained, the power unit of the apparatus shown in said first mentioned patent is supplied from the terminals 46 which in turn are disconnected from the source of supply when switches 64 and 66 are opened, the transformer and all other electric devices in the power unit are de-energized when the closure 12 is moved to its open position (Fig. 1). It will be noted that switches 64 and 66 are disposed in the two sides of the electric circuit so that they constitute double pole switching means to interrupt both sides of the supply lines to the power unit and hence to the lamp in the housing when the door 12 is opened.

In the event that it becomes necessary, for purposes of repair or maintenance, to provide high voltage in the lamp housing with the door or closure 12 in the open position thereof, this can be accomplished by a service man or electrician who is familiar with the operation of the interlock mechanism. In this connection, with the door 12 open, the rod end 116 can be grasped and pulled in the direction of arrow B in Fig. 3 so that the reflex portions 105 ride out of the companion recess portions and onto the outer surface of the rod rearwardly thereof, as illustrated in Fig. 5, for flexing the parts 86 to close the switches. When rod 116 is manually moved to the position illustrated in Fig. 5, to close the switches 64 and 66 under special conditions even though door 12 is open, as just explained, spring is ineffective to return said rod to its normal switch-open position and said rod remains stationary in switch-closed position by the frictional engagement of members 104 with said rod. However, when. the door is closed, member 122 pushes said rod to its normal switch-closed position (Fig. 3) ready to be moved by spring 115 to its switc -open position when the door is opened.

While I have shown and described the preferred em- Having thus described my invention, what I claim and desire to secure by Letters Patent, is:

1. In an electrical device having a main and an auxiliary housing, the combination comprising a movable closure means for said main housing, a pair of terminals on said auxiliary housing adapted to be connected to a low voltage energy source, a step up transformer within said auxiliary housing, a high voltage illuminating device in said main housing, low voltage circuit means for supplying cnergy from said terminals to said transformer, high voltage circuit means for supplying energy from said transformer to said illuminating device at the proper high voltage, means for controlling both said high and low voltage circuit means, comprising a pair of switches interposed in said low voltage circuit means between said terminals and said transformer, a rod slidably mounted in said auxiliary housing and having a pair of notches defined therein, each of said switches having an actuating gethcr, spring means for biasing said rod to a first position in which both said notches are moved into engagement with said switch actuating parts whereby to operate said switches to open said circuit means, a portion of said rod extending outwardly of said auxiliary housing and being operatively engageable with said closure for moving said rod to a second position when said closure is moved into closing relationship with said main housing, said notches in said rod being disposed to one side of said open said circuit means when said closure is moved out of closing relationship, said rod being adapted to be manually moved longitudinally to a third position in connected to a low voltage energy source, a step up transformer in said auxiliary housing, low voltage circuit means in said auxiliary housing, at least a branch of said circuit means extending from said terminals to the primary winding of said transformer, and high voltage circuit means extending between said auxiliary housing and said main housing and connecting said illuminating device to the secondary winding of said transformer, and means controlling said low and high voltage circuit means, comprising a pair of switches disposed in said auxiliary housing and interposed in said low voltage circuit means and adapted to open and close said low voltage circuit means whereby to energize and deenergize both said low and high voltage circuit means, a rod having a pair of notches defined therein, said rod being slidably mounted in said auxiliary housing and having a. portion thereof extending outside said auxiliary housing, each of said switches having an actuating part comprising an elongated spring arm engaging said slidable rod, said spring arms being positioned relative to said rod so that both move into and out of their associated notches in unison whereby to open and close, respectively, their associated switches, said portion of said rod extending moving said rod out of said third position, whereby both said circuit means can be energized when said door is out of closing relation with said main housing.

References Cited in the file of this patent UNITED STATES PATENTS

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