US3530501A - Plural visual indicator assembly energizable through two input terminals - Google Patents

Description

Sept. 22, 1970 P. J. VAN BENSCHOTEN 3,530,501

PLURAL VISUAL INDICATOR ASSEMBLY ENERGIZABLE THROUGH TWO INPUT TERMINALS Filed Dec. 11, 1968 INVENTOR P k %m Zane/ om BY 67 @M dd! ATTORNEYS United States Patent PLURAL VISUAL INDICATOR ASSEMBLY ENER- GIZABLE THROUGH TWO INPUT TERMINALS Peter J. Van Benschoten, Rancho Santa Fe, Calif., as-

signor to Oak Electro/Netics Corp., a corporation of Delaware Filed Dec. 11, 1968, Ser. No. 782,972 Int. Cl. HOlj 1/60 US. Cl. 315-129 6 Claims ABSTRACT OF THE DISCLOSURE This invention relates to a circuit and assembly for energizing a plurality of loads, and more particularly to a circuit for selectively energizing one or a combination of loads through a single pair of input terminals.

A pair of visual indicator lamps are typically energized, either individually or simultaneously, through three input terminals, in which one terminal is connected in common to both lamps. By connecting an electrical source across an individual terminal and the common terminal, either one of the lamps can be energized. By connecting the electrical source across both individual terminals, both lamps are energized.

While such a three input terminal circuit is satisfactory in many applications, it is sometimes desirable to be able to individually or simultaneously energize the pair of lamps through a single pair of input terminals. For example, the present invention allows a two lamp assembly to be substituted for a one lamp assembly, without requiring replacement of the two terminal lamp socket receptacle.

In addition, a three terminal lamp assembly is considerably more expensive to tool and manufacture than a two terminal lamp assembly. The cost is further increased when the lamp assembly is to be incorporated with other structure, such as in an illuminated pushbutton switch. Each electrical terminal requires sliding contacts or other structure and an additional terminal significantly increases the cost of the assembly.

One object of the invention is the provision of a circuit for energizing either individually or in combination a plurality of loads through a single pair of input terminals.

One feature of the invention is the provision of a two lamp indicator assembly in which either or both lamps may be energized through a single pair of input terminals.

Another feature is the provision of a two lamp energizing circuit in which diodes are associated with each lamp in order to pass DC currents of different polarity to each lamp. When AC voltage is connected to the circuit, both lamps are energized.

Further features and advantages will be apparent from the following description and from the drawings, in which:

FIG. 1 illustrates a two lamp assembly incorporated in an illuminated pushbutton switch;

FIG. 2 is a schematic diagram of the lamp circuit of FIG. 1;

FIG. 3 is a schematic diagram of the lamp circuit connected to a power supply for energizing the lamps; and

FIG. 4 is a diagram of the voltage Waveform available from the power supply of FIG. 3.

While an illustrative embodiment of the invention is ice \ shown in the drawings and will be described in detail herein, the invention is susceptible of embodiment in many diiferent forms and it should be understood that the present disclosure is to be considered as an exemplification of the principles of the invention and is not intended to limit the invention to the embodiment illustrated. The scope of the invention Will be pointed out in the appended claims.

Turning to FIG. 1, a plurality of energizable loads are illustrated, in the form of a pair of visual indicator lamps 10 and 11. The lamps are contained within a single socket assembly 13 which is slidably mounted within a receptacle assembly, not illustrated. These assemblies form an illuminated pushbutton switch, in which an operator manually depresses socket assembly 13 in order to engage the receptacle and energize the lamps 10 and/or 11.

Lamps 10 and 11 are mounted Within a cylindrical insulated housing 16 having a base 17, of insulating material, at one end, with a pair of electrical input terminals 19 and 20 secured thereto. The opposite end of cylindrical housing 16 is covered with a transparent lens 22 which allows light from lamps 10 and 11 to be transmitted therethrough when the lamps are energized. An opaque wall 24 within housing 16 separates the lamps, forming light tight enclosures or chambers 25 and 26 therefor. The lamps are mounted on a wall 27 of insulating material, which forms the bottom portion of the chambers.

Electrical input terminals 19 and 20 may take any desired form, and are illustrated for an illuminated pushbutton switch assembly. Terminal 19 consists of a button extending from insulators 28, which are mounted at the end of a cylindrical metal housing 29 which forms contact 20. As assembly 13 is pressed downwardly, it engages a conventional plunger and contact pin of the switch receptacle, thereby connecting contacts 19 and 20 to the circuit of FIG. 3.

In FIG. 2, the lamp circuit contained within socket 13 is illustrated in detail. Either lamp 10 or 11, or both lamps, may be energized by electrical power from terminals 19 and 20. For this purpose, one terminal line of each of the lamps 10 and 11 is connected to a common line 40 which directly connects to terminal 20. The opposite terminal line of lamp 10 is connected through a unidirectional conduction device, in the form of a diode 42, to a common line 43 which directly connects with terminal 19. Similarly, the opposite terminal line of lamp 11 is connected through another unidirectional conduction device, in the form of a diode 45, to line 43. Diodes 42 and 45 are oppositely poled, so that only diode 42 is conductive when terminal 19 is positive relative to terminal 20, and conversely only diode 45 is conductive when terminal 19 is negative relative to terminal 20.

In operation, terminals 19 and 20 are connected to an electrical source which can supply energy of different characteristic, herein positive polarity DC voltage, to either terminals 19 or 20, or an AC voltage thereacross. When terminal 19' is coupled to a positive DC voltage relative to terminal 20, a current path is formed through line 43 and diode 42, lamp 10, and line 40 to terminal 20. This causes only lamp 10 to be energized. Lamp 11 cannot be energized because diode 45 is back-biased and blocks current flow through the lamp. When the polarity of the DC voltage is reversed, a current path is formed from terminal 20 and through lamp 11, diode 45, and line 43 to terminal 19. In this case, only lamp 11 is energized.

When both lamps 10 and 11 are to be energized, an AC voltage is connected to terminals 19 and 20. When the AC voltage goes positive at terminal 19*, lamp 10 is energized, and when the AC voltage goes positive on the opposite half cycle at terminal 20, lamp 11 is energized. The AC voltage is chosen to have a frequency in excess of the perception time of the human eye. Thus, although each lamp is alternately energized, the visual perception to the human eye is that of a continuous energized lamp.

Diodes 42 and 45 are mounted within housing 29, as seen in FIG. 1. As illustrated, the cylindrical housing 29 extends downward from base 17. Diodes 42 and 45 are placed within the opening defined by housing 29 and insulator 28, after which an epoxy resin may be poured therein in order to hold the diodes in place.

A power supply suitable for energizing the circuit of FIG. 2 is illustrated in FIG. 3. A transformer 52 has an input winding 53 with a pair of terminals 54, 55 connectable to a conventional source of 60 cycle AC line current. An output winding 56 of transformer 52 has a turns ratio, relative to input winding 53, chosen to step down the voltage to a magnitude suitable for lamps and 11. One side of winding 56 is directly connected to the receptacle structure which engages terminal 20. The other side of winding 56 is connected to a unidirectional conduction device, as a diode 60, poled in the same direction as diode 42. The cathode side of diode 60 is connected to another unidirectional conduction device, as diode 62, oppositely poled to diode 60 and having an anode directly connected to the receptacle structure which engages terminal 19 when the assembly of FIG. 1 is depressed.

Diodes 60 and 62 are shunted by a pair of normally open, single-pole, single-throw switches and 66, respectively. When only switch 64 is closed, diode 60 is shorted and has no eifect in the circuit. When only switch 66 is closed, diode 62 is shorted and has no effect in the circuit. When both switches 64 and 66 are closed, both diodes 60 and 62 are shunted and effectively disconnected from the circuit.

In operation, when lamp 10 is to be energized, switch 66 is closed, thereby shorting diode 62. Each time the voltage at the upper side of winding 56 goes positive, shown by the solid line 80 in FIG. 4, current flows through diode 60, switch 66, terminal 19 (when the socket is depressed) and diode 42 to lamp 10, and thence through line 40 and terminal to the lower side of Winding 56.

When only lamp 11 is to 'be energized, switch 64 is closed, shorting diode 60. Each time the upper side of winding 56 goes negative, shown by the dashed lines 82 in FIG. 4, current flows through terminal 20 (when the socket is depressed) and line 40 to lamp 11, and thence through diode 45, line 43, terminal 19, diode 62 and switch 64 to the upper side of winding 56.

When both lamps are to be energized, both switches 64 and 66 are allowing both half cycles 80 and 82 of alternating current to pass to terminals 19, 20 and energize lamps 10- and 11. That is, during the positive half cycle 80, FIG. 4, lamp 10 is energized, and during the negative half cycle 82, lamp 11 is energized. Since conventional AC line current has a frequency of 60' cycles per second, each lamp is energized 60 times per second with a 50% duty cycle. "Because this repetition rate is above the perception rate of the human eye, lamps 10 and 11 will appear to be continuously energized.

I claim:

1. In an indicator system having a male assembly movable into contact with a female receptacle to allow selective energization of a pair of visual indicators contained within the male assembly, the improvements comprising:

a housing forming said male assembly and having an external surface with only two conductive areas thereon which define two terminals for contacting said female receptacle to conduct electrical energy from said female receptacle to said male assembly, said pair of visual indicators being contained within said housing;

first circuit means within said housing and connecting said two terminals to said pair of indicators for energizing one of said indicators when electrical energy of one characteristic is present across said two terminals and for energizing the other of said indicators when electrical energy of a different characteristic is present across said two terminals; and

source means for connecting electrical energy through said remale receptacle to said two terminals, including second circuit means actuable when one of said indicators is to be energized for supplying electrical energy of said one characteristic and actuable when the other of said indicators is to be energized for supplying electrical energy of said different characteristic.

2. The indicator system of claim 1 wherein said first circuit means includes a pair of unidirectional conduction devices and means connecting each of said devices to a different one of said indicators for energizing the indicator only when a voltage of a polarity corresponding to the direction of conduction of the device is present across said two terminals, wherein said characteristic corresponds to the polarity of voltage from said source means. I

3. The indicator system of claim 2 wherein said second circuit means includes means actuable when both of said indicators are to be energized for supplying voltage of alternating polarity through said female receptacle to said two terminals, said first circuit means alternately causing each of said unidirectional conduction devices to pass current and alternately energize the indicator associated therewith.

4. The indicator system of claim 3- wherein said AC voltage has a frequency at least two times greater than the perception rate of the human eye, said first circuit means alternately energizing each visual indicator at a repetition rate greater than the perception rate of the human eye, whereby said pair of visual indicators appear to the human eye to be continuously energized.

5. The indicator system of claim 3 wherein said second circuit means includes a third unidirectional conduction device connected to said AC voltage supplying means for rectifying the AC voltage to produce half cycle voltage of positive polarity, a fourth unidirectional conduction device connected to said AC voltage supplying means for the AC voltage to produce half cycle voltage of negative polarity, and switch means actuable to shunt both said third and fourth unidirectional conduction devices to couple AC voltage of positive and negative polarity through said female receptacle to said two terminals.

6. The indicator system of claim 1 wherein said housing includes lens means transparent to light energy emitted by said pair of visual indicators when energized, opaque means in said housing for forming a pair of separate light chambers, each chamber being adjacent said lens means, and means mounting each of said visual indicators in a different one of said pair of chambers.

References Cited UNITED STATES PATENTS 3,019,369 1/1962 Zarleng 315209 3,110,810 11/1963 Fransen 250-- 3,268,742 8/1966 Pinckaers 30788.5

JOHN HUCKERT, Primary Examiner R. F. POLISSACK, Assistant Examiner U.S. Cl. X.R.

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