BRECCIAROLI, Roberto (Via Aurelio Saffi 34, Roma RM, I-00155, IT)
| CLAIMS 1. A push button (1), in particular for military applications, comprising a light source (114) and a control system thereof, said light source (114) comprising a plurality of lighting devices (114) arranged grid-like. 2. The push button (1) according to the preceding claim, wherein said control system comprises a control circuit (500) comprising means for setting one among a plurality of predefined configurations of said lighting devices (114). 3. The push button (1) according to the preceding claim, wherein said means comprises a plurality of electrical connection members insertable and/or removable according to a plurality of combinations, such that to each of said combinations of connection elements there corresponds one of said predefined configurations of the lighting devices (114). 4. The push button (1) according to any one of the preceding claims, wherein said control system further comprises means (200) for regulating a supply voltage of said lighting devices (114). 5. The push button (1) according to the preceding claim, wherein said regulating means ■ (200) comprises a DC/DC converter (201) apt to receive as input a continuous supply voltage substantially comprised between 8 V and 45 V, and to return as output a driving signal of said lighting devices (114), such that their luminance falls within a predefined range independent of the chromatic features of each of them. 6. The push button (1) according to the preceding claim, wherein said control system further comprises control means for controlling the driving signal, comprising at least one control input (202, 202') apt to receive as input a control signal, and to provide as output a signal apt to cooperate with said driving signal in a manner such that the luminance of each of said power-supplied lighting devices (114) be variable depending on said control signal. 7. The push button (1) according to the preceding claim, wherein said control means comprises a transistor stage (203, 203') for each of said lighting devices (114), a respective control input (202, 202') corresponding to each transistor stage (203, 203'). 8. The push button (1) according to any one of the preceding claims, comprising one or more modules (11 , 12, 13) connectible thereamong. 9. The push button (1) according to the preceding claim, wherein said one or more modules comprise: • a head module (11), comprising said light source (114); · an end module (13), comprising means (131) for the electrical connection with a circuit for power-supplying said light source (114), • an intermediate module (12), comprising a mechanism (125, 129) actuated by said head module (1 ) and apt to cooperate with said end module (13) so as to open/close the power-supplying circuit; wherein at least one between said head (11) and end (13) modules is reversibly connectible with said intermediate module (12). 10. The push button (1) according to the preceding claim, wherein said power- supplying circuit comprises said control system of said light source (114). 11. The push button (1) according to the preceding claim, wherein said intermediate , module (12) comprises a power-supplying circuit switch (124) activated (set ON) by said mechanism (125, 129). 12. The push button (1) according to the preceding claim, wherein said ON/OFF mechanism (125, 129) of said switch (124) is of bistable type. 13. The push button (1) according to the preceding claim, wherein said mechanism (125, 129) comprises a member (125) apt to slide inside said intermediate body (12) ' between a first and a second position, respectively of activation (ON) and deactivation (OFF) of said switch (124). 14. The push button (1) according to one of the claims 9 to 13, wherein said lighting devices (114) are arranged grid-like on a flexible board (115) internal to said head module (11). 15. The push button (1) according to the preceding claim, wherein said control system is obtained on an electronic board (121) interposed between said flexible board (115) and said end module (13). 16. The push button (1) according to any one of the preceding claims, further comprising an outer holding case (2). |
DESCRIPTION
The present invention relates to a composable modular push button, preferably used on control panels for military-type applications, having a light source and a control system thereof.
Generally, panel push buttons are made for use on sites for command and control of aerospace, naval and ground means. The typology of push buttons at issue requires high reliability in operation, with high visibility of the command: in particular, for military and aeronautical use they must be qualified and compliant with Standards MIL -STD - 202, MIL PRF - 22885.
The modular push button according to the invention allows to have a visible luminous area divided into plural sections (1÷4), which highlight the state of internal parameters, opting among 6 different colors and setting the desired legend. Moreover, it is possible to select between colored background or colored legend.
The modular push button subject of the present invention is preferably illuminated with electronically controlled variable-color LED devices, is advantageously universal, having a double mechanical positioning for control of two or four switches (or microswitches), with interchangeable connection module. Assembly is preferably , carried out from panel, with front insertion.
The present invention stems from taking into account the needs of such a typology of devices intended for military applications, whose standards impose specific operating parameters, such as color chromaticity, operating temperature, luminosity of indicating labels and possibility of operating under certain environmental conditions (NVIS and SLR), where the need to instantly change operation features is required . ' In view of the above, voltage control of the circuit represents one of the possible features of the present invention. Taking into account the action range of the dimming voltage, there is the need to correctly set the Min and Max current flowing on the diodes, recalling that the life of the optical device strongly depends on the maximum admissible current. In fact, chromaticity and luminance of LED devices depend on the absorbed current, therefore on the voltage upstream of the circuit; moreover, to have the same light emission differently colored LEDs need to be driven by different currents.
In order to guarantee stability and efficiency o f the above-mentioned parameters, circuits guaranteeing temperature stability have to be provided.
Different circuit methodologies allow to obtain a variation of LED-absorbed current against a variation in supply voltage. PWM technique exploits the duty cycle variation of an alternating square-wave signal to obtain different luminosities.
Complex digital logics have to be predefined for the implementation of this technique. The same operation may advantageously be performed by intervening directly on LED activation command voltages which, typically for the applications considered, is a direct voltage DC (direct current).
Turning the application of the circuit at issue to military applications, it is found that the standards provide 28Vdc as main supply voltage for supplying cockpits (airplanes, helicopters, etc.). By using common LEDs with average operation features of 5V/20mA, the control logic circuit necessarily defines a specific Luminance/Voltage curve.
It is important that the curve follows a pattern defined by standards indicating about 14Vdc for NVIS conditions and about 28Vdc for SLR conditions.
According to an aspect of the invention, a DC/DC converter is used to which, as will be described in detail hereinafter, is entrusted the task of transforming the command voltage into a suitable LED driving signal.
The use of the DC/DC converter allows to obtain very high performances in terms of ■ effectiveness, consumption and heat dissipation with reference to the known art, as well as to miniaturize the circuit inside the IPBS (Illuminated Push Button Switch).
Advantageously, there are attained a high efficiency and a very low heat dissipation with respect to linear DC reduction techniques, like e.g. the use of dropping resistors. According to an aspect of the invention, a novel technique was developed for controlling the parameters characterizing the LED devices, in particular the possibility of varying the luminous intensity against a voltage sweep, commonly defined as "dimming" in the illuminotechnical field, though keeping constant over time the circuit- delivered current and the operating temperature, compatibly with what is stated by MIL standards.
Still further advantages, as well as the features and operation modes of the present invention, will be made evident in the following detailed description of a preferred embodiment thereof, given by way of example and not for limitative purposes. Reference will be made to the figures of the annexed drawings, wherein:
Figures 1 and 2 depict in a perspective view a modular push button 1 according to the present invention;
Figure 3 depicts an exploded axonometric view of a modular push button 1 according to the present invention;
Figures 4 and 5 show two exploded axonometric views of two different details of
Figure 3; Figure 4 shows a detail of Figure 3;
Figure 6 shows a detail of the push button according to the present invention, Figures 7, 8A - 8C show electrical diagrams of a control system of the push button subject of the present invention;
Figures 9A-9B show a control circuit of the push button subject of the present invention.
Detailed description of the drawings
Referring to Figures 1 and 2, a modular push button subject of the present • invention is shown, generally denoted by reference number 1. As can be seen in the figures, the modular push button 1 is preferably inserted inside an outer holding case 2.
Referring to Figure 3, the modular push button 1 comprises a head module 11 , an intermediate module 12 and an end module 13, connectible thereamong.
The head module 11 comprises thereinside a light source, not shown as preferably housed inside the module 11. In particular, the light source comprises a plurality of lighting devices, which in the embodiment described herein by way of example and not for limitative purposes are LED-type devices, well-known in the technical field of reference.
The end module 13 comprises means 131 for the connection with an external circuit (not depicted), apt to power-supply, when activated, the LEDs of the head module 11 , which will substantially act as spy lights for the closing just of the circuit.
The modular push button 1 further comprises an intermediate module 12, interposed between the head 11 and end 13 modules, and comprising a mechanism (not shown), actuated by the pressing of the head module 11 , apt to cooperate with the end module 13 so as to open/close the external circuit, thereby concomitantly causing the activation or deactivation of the LEDs arranged in the head module 11.
.. The head module 11 comprises a pin 111 which engages in a cylinder 122 and is made integral to the latter by means of a microsphere-shaped mechanical device fitting into a recess 123 thanks to the action of a spring 112.
According to the invention, at least one between the head module 11 and the end module 13 is reversibly connectible to the intermediate module 12. Preferably, in the preferred embodiment shown herein, both modules 11 and 13 are reversibly ' connected, so as to both be individually replaceable with other alike or different-type
(e.g., having different functions) ones, with no need to replace the entire push button 1.
The push button 1 according to the invention further comprises a control system for controlling the LEDs themselves, the latter obtained on an electronic board 121 , preferably supported by the intermediate module 12 and interposed between the head module 11 and the end module 13. Preferably, the electronic board 121 is semi-rigid and made of FR4.
Therefore, it will be appreciated that the end module 13 constitutes the connection module of the push button 1 for connection to the outside and comprises just the connections to the external circuit, and in particular to the control electronic board 121. Therefore, such a module is advantageously extractable and replaceable, allowing the ■ connection of the modular push button 1 , e.g., on PCB, on standardized connectors, with wires or connectors ad hoc when required.
Referring to next Figure 4, the head module 11 is shown in an exploded axonometric view. As mentioned above, it comprises the pin 112 surrounded by the spring 111.
In figure 4 the LEDs can now be seen, denoted by reference number 114, preferably four in number and arranged grid-like on a flexible board 115, preferably made of kapton, positioned inside a spacer 113 into contact with the pin 111 and so as to arrange the LEDs into a housing 116. Given the grid-like arrangement of the four LEDs depicted, the housing supports a cross-piece 117 apt to keep distinct toward the outside the lights produced therefrom, particularly when the lights are of different colors. The flexible board 115 further comprises a mount 118 for mounting to the control electronic board.
Finally, the head module 11 comprises an outer glass 119 overlapped in sequence to a label 1111 , a diffuser 1121 and a reflector 1131. Therefore, the activation of the LEDs 114, caused by the pressure of the push button exerted on the head module 11 , causes lighting of the glass 119 according to the specific arrangement of the LEDs ■·: (colors selected for each of them and their arrangement on the flexible board 115).
Referring to Figure 5, an exploded axonometric view of the intermediate module
12 is shown. Thereinside, it comprises a switch 124 that is actuated by the mechanism for the opening/closing of the external power-supplying circuit for LEDs activation.
The mechanism of the intermediate body 12 is preferably of bistable type, and comprises a member 125 apt to slide between a first and a second position, respectively of switch activation (ON) and deactivation (OFF).
In particular, the member 125 comprises the cylinder 122 that, urged by a pressure exerted on the outer glass of the head module, compresses a spring 126 and then a bottom piston 127, which in turn activates the switch 124. The bottom piston 127 remains in the compressed position, whereas the cylinder 122 goes to position itself in a midpoint of a stroke thereof. This is made possible by a flexible and shaped guide pin 128, integral to the cylinder 122, sliding inside a recess 129 obtained within an external guide half-body 1211 of the intermediate body 12, having a geometric profile such as to allow the above-mentioned positioning. By pressing again the head module the guide pin 128 slides inside the recess 129, whose profile allows to bring the member 125 in the second position, removing the bottom piston 127 from the switch 124 and thereby opening the circuit.
The guide half-body 1211 is connected to a clamping half-body 1212 by band clamps 1213.
In figure 6 the flexible board 115 can be seen, supporting the LEDs 114 and comprising the mount 118 for its connection to the control board 121.
Therefore, the push button comprises a control system for controlling the light source, and in particular a control system for controlling the LED devices, arranged in the head module as highlighted above.
Referring to Figure 7, it is depicted an electrical diagram 200 of the control system of the push button subject of the present invention. In particular, the control system comprises means 201 for regulating a supply voltage V of the LED devices 114.
According to a preferred aspect of the invention, such regulating means 201 comprises a DC/DC converter 201 apt to receive as input a continuous supply voltage V substantially comprised between 8 V and 45 V, and to return as output a driving signal of the LED devices 114, such that their luminance falls within a predefined range independent of the chromatic features of each of them.
Moreover, the control system according to the invention comprises control means for controlling the driving signal, comprising for each LED device 114 a control input 202, 202', apt to receive as input a control signal, e.g. of linear or step type, and to provide as output a signal apt to cooperate with the control signal so that the luminance of each of said power-supplied LEDs 114 depend on the respective control signal. Preferably, the control means comprises for each control input 202, 202', and therefore for each LED 114, a respective transistor stage 203, 203'.
Preferably, the DC/DC converter block 201 has the task of transforming input voltage, which may be comprised between 5 ÷ 35 Vdc.
The resistors downstream of the DC/DC converter block 201 allow to set the default luminance of the LEDs according to MIL standard specifications.
The means for controlling the driving signal allow, upon variation of the external signal of luminous intensity, to vary the same according to two different modes (based on the configuration of the blocks). In fact, such a variation may be of step type (e.g., 3 steps) or of linear type. In figure 8A an electrical diagram 300 for the regulation of a single LED is shown. Considering this diagram, it is evident that the mesh formed by R2, R3, D1 determines the current that must flow on the LED depending on the voltage applied as input.
In figure 8B a diagram 400 is shown, this time of double buffer type, always for the regulation of a single LED. The diagram 400 introduces a second transistor, Q2, which is used to define a different pattern of the current. Moreover, the same Q2 can also be . used to drive a second LED. The parameters to be regulated, for what has been illustrated above, are R7, R8 and R9.
In figure 8C it is shown the electrical diagram 200 for controlling two LED devices. It can be used for the independent command of plural LEDs, where a novel network of commands for the LED2 is added in cascade.
Referring to Figures 9A and 9B, the system for controlling the push button ' comprises a control circuit, generally denoted by number reference 500, designed on the basis of the diagrams of the preceding figure and dedicated to the push-button. The circuit 500 is transferred on two tables (9A and 9B) so as to be better readable.
The circuit 500 comprises means for setting one among a plurality of predefined combinations of the LED devices. The 4 LEDs placed in the head module can therefore be controlled according to the styles predefined by MIL standards, using only the electronic circuit 500, where the configuration is selected by means of a matrix bridging system.
In particular, the means comprises a plurality of electrical connection members (not depicted) insertable and/or removable according to a plurality of combinations, such that to each combination of the connection elements there corresponds a respective , predefined configuration of the LED devices.
Hence, it will be appreciated that the control circuit 500 groups all functions, commands and controls defined by the above-mentioned standards, as well as a circuit theoretical approach for the driving of LED (Light Emitting Diode) light sources.
A specific exemplary technique of predefined combinations of the LED devices is reported hereinafter: LED CIRCUIT SCHEMATIC BLOCK DIAGRAMS AND POlARffY
STYLE ¾¾ ■
The control circuit has a matrix system of electrical connection members, also referred to as "jumpers" in technical jargon, allowing to implement all LED connection styles, envisaged in particular by standard MIL 22885, by using a single PCB without having to resort to plural printed circuits.
In particular, is has to be noted that with such a system it is possible to implement "current sinking" and "current sourcing" command modes, with no need to replace circuit components.
Referring to the positions of the Jumpers denoted by letters J in figure 9, and to the specific exemplary technique of the various combinations, hereinafter it is reported an example of configuration matrix for obtaining, according to whether the Jumper is inserted or not inserted, the various predefined LED combinations: Referring to the reported diagram, the circuit 500 has a matrix system of jumpers that allows to implement all LED connection styles envisaged by standard MIL 22885, using a single PCB and without having to resort to plural printed circuits.
Beside this possibility, by using the jumpers matrix system it is possible to configure the push button according to the client's specifications, by suitably varying the connections of the jumpers to the PCB board.
• With this system it is possible to implement "current sinking" and "current sourcing" command typologies with no need to replace circuit components.
The presence of jumpers J15 and J16 allows to manage, for the two sections (UP and DOWN), one common or two commons for power supplies and earth.
Always referring to the diagram reported, hereinafter the use of the remaining jumpers will be illustrated, by way of example and not for limitative purposes, proceeding with an analysis of the "Common Anode" and "Common Cathode" typologies, in the different 8÷45Vdc and 5Vdc versions. Such an analysis, referred to a single section (UP) is likewise applicable to the DOWN section.
8÷45Vdc TYPOLOGY
Common cathode - the cathodes being in common, command typology is high-level (+Vcc) and occurs by concomitantly activating the DC/DC circuit converter and the transistor driver related to the LED to be activated (Q1 or Q2). The jumpers J3, J4 are in a closed configuration (J 11 and J12 open) and return the command signal to the base of the transistor drivers Q1 and Q2. In this configuration, references J23-J5 house switching diodes, therefore constituting an OR logic gate that allows to share the DC/DC converter for independent activation of the two LEDs of the section. If . necessary, references J23-J5 can be kept in an "open" configuration in case it be desirable to power-supply the DC/DC converter with a separate external power supply; this latter configuration can be employed in case of need to set a minimal luminance. Common anode - In this case, it is the anodes that are in common (shared) and the command typology is low-level (GND). In a mode complementary to what has been stated above for jumpers J3, J4, use of jumpers J11 and J12 is resorted to; jumpers ' J11 and J12 are set in a closed configuration (J3 and J4 open) directly connecting the external commands to LED cathodes. J5 and J6 are in a closed configuration, so as to always keep the DC/DC converter active and therefore power-supply the anode branch by means of the transistors drivers Q1 , Q2.
Jumpers J17, J18, J19, J29, jointly with those present on the Kapton Display, configure the number of LEDs which are activated by each single command,
5Vdc TYPOLOGY In this case, voltages in play are relatively low and the DC/DC converter + transistors driver circuit can be eliminated. J25, J28 are in a "closed" configuration and allow to use the same circuit provided for the 28VDC version, both for the Common Cathode" and "Common Anode" configuration. R9, R6, R10 and R5 are dropping resistors to be calibrated.
Finally, by way of example and not for limitative purposes, hereinafter a table is reported, carrying preferred technical specifications of electrical components used for the circuit of Figure 9:
* The kapton display is comprised of 4 or 8 LEDs, colored according to required configuration type.
** Red, Green, Amber, Yellow, White, Blue.
The present invention has hereto been described with reference to a preferred embodiment thereof. It is understood that other embodiments might exist, all falling within the concept of the same invention, and all comprised within the protective scope of the claims hereinafter.