Patent Application
20050243489
This invention relates generally to devices used with circuits that easily and quickly connect together and specifically to circuits constructed by children or students. It insures that the circuit will be safe and is designed to prevent damage to components or any object or person in close proximity to these components.
There are toys and teaching aids that use a mechanical connector to quickly assemble electronic circuits. Sooner or later these components are connected to a power source such as a battery. If the circuit allows too much current to flow, certain devices may become extremely hot and even explode.
Fuses may be connected in series with the power source that will open when excessive current flows. Since most inexpensive fuses must be replaced, this process is inconvenient and allows the child or student the option of using a conductor that eliminates the protection device. Mechanically resetable fuses are expensive and some can be held in the on position to eliminate the protection feature of the fuse.
Another safety problem exists when polarized capacitors are installed backwards in electronic circuits. The capacitors leakage current will increase significantly and the device will rise in temperature and may even explode. Many existing products do not consider the safety of the child or student when allowing for the insertion of capacitors and other “off the shelf” electronic components.
Quick connect assembly systems currently being sold consist of a box of electronic devices mounted to quick connect bases. Diagrams for hundreds of circuits are included to educate a student or entertain a child. When these circuits are assembled the child can listen to a radio station, send a flying saucer on mission, create and store sounds . . . just to name a few. Sooner or later the child or student will either connect a component incorrectly or decide to experiment with the connections.
Whenever new circuits are constructed the potential for damage to the parts will occur and safety problems will arise.
To take care of excessive current and circuit shorts, a specially designed battery holder and AC/DC interface containing a PTC resetable fuse has been invented. A positive temperature coefficient (PTC) resetable fuse electronically limits the maximum current and automatically resets when the problem is removed. This device can be inside the module and not available to the child or student for maximum amount of protection. When the battery holder provides the input power, the PTC resetable fuse is in series with the positive terminal. Even if the external power supply with quick connect circuit type connector is used, the student or child is protected since it also has the PTC resetable fuse in series with the positive terminal.
This PTC fuse will rise in resistance value and limit the amount of current flowing whenever it is raised in temperature. By placing it in series with electronic components, it will limit both AC and DC currents to a safe level if the parts are used incorrectly. As current increases the temperature of the PTC also increases. This raises the resistance of the PTC which lowers the voltage and prevents damage to the electronic components. As soon as the electrical current level is restored to a safe level, the temperature of the PTC will drop allowing circuits to receive the proper voltage. Placing the PTC inside the battery holder or inside the quick connect circuit AC/DC power plug, prevents the user from touching it when it is at an elevated temperature. The use of non-polarized capacitors will help take care of incorrect DC connection of capacitors but will not cure the problem of extremely high AC currents through capacitors that can also cause heating and explosion. By placing PTC resetable fuses, that cannot be removed by the child or student, in series with sensitive electronic components of all these problems can be eliminated. Adding the PTC resetable fuse in series with any “off the shelf” component will likewise prevent excessive current from flowing. Any module that accepts non-polarized capacitors or “off the shelf” components should have this type of protection.
The accompanying Figures illustrate the following:
The present inventions consist of an improved battery holder module 600, Positive Temperature Coefficient Automatically Resetable Fuses 103, 104, 404 and 605, a specially designed power source 100 with unique stackable output plugs 101 and 102, a quick connect module 400 for electronic components, a clear see through plastic base 500 with mechanical compatible connectors for quick connect circuit interfacing some of which are shown as components 510-516, 600. The battery holder module 600 is designed to be used as a direct replacement for existing quick connect circuit type battery holder modules. The clear plastic base 500 serves as a support to mount the quick connect circuit modules.
The quick connect circuit systems that are presently being sold use battery holders that can be placed in series to stack the voltages. The addition of the Positive Temperature Coefficient Automatically Resetable Fuse 605 prevents shorts from producing heat that can damage the battery holder and cause possible injury to the user. A custom wall adapter power source 100 with multiple outputs 101, 102 must also be stackable to interface properly with the battery powered quick connect circuit designs in use today. Each output plug 101, 102 is driven from an isolated secondary transformer coil 204, 205 and uses a separate regulating circuit 207, 208 respectively. There may be any number of isolated outputs 101, 102 to allow for increased stacking capability. Each one of the regulated circuits 207, 208 contains current limiting features to further insure safety when shorts or bad wiring is present. The unique power connectors 101, 102 are designed to mate only with other snap circuit modules. The actual shape of the connectors 101, and 102 is important because this unique design prevents the battery module 600 from being directly connected in parallel with the AC/DC power source connectors 101, 102. This further increases safety by preventing a child or student from easily plugging a battery module 600 in parallel with a power source connector 101, 102.
The regulating circuit shown in
Figure shows the input to the DC Regulator as a secondary winding 300 on a transformer. This could be either of the two secondaries 204, 205 shown in
All the modules use a base 500 similar to the one shown in
Accordingly, although the invention has been described by reference to a preferred embodiment, it is not intended that the novel assembly be limited thereby, but that modifications thereof are intended to be included as falling within the broad scope and spirit of the foregoing disclosure, the following claims and the appended drawings.
