Patent Publication Number: US-6671159-B2

Title: Power source breaker

Description:
BACKGROUND OF THE INVENTION 
     The present invention relates to an electric power source breaker which isolates a power supply circuit by means of sublimation of a gaseous actuating reagent, and relates in particular to a compact power source breaker which can forcedly and surely isolate a power supply circuit in case of something unusual such as short circuiting of a wire harness, collision of road vehicles. 
     FIG. 1 is a systematic diagram showing an example for electronic automobile parts to which a conventional power source breaker is applied. As shown in the figure, the electronic automotive part  100  includes a power supply circuit assembled by connecting a battery  101  of an automobile to each load  102 - 104  disposed at each location of the automobile using a wire harness  106  with electric wires  105 , and a power source breaker  107  intervened in the power supply circuit. 
     When a circuit-cut signal generated at a power source controller  108  is input in case of something unusual such as short circuiting of a wire harness  106 , collision of road vehicles, the power source breaker  107  can stop supplying power from the battery  101  to each load  102 - 104  etc. through releasing a lock in a manner as described hereinafter according to FIG.  2 . 
     FIG. 2 is a configuration of a solenoid-type power source breaker  107 A showing an example of the power source breaker  107  in FIG. 1, and FIG. 2A is a top view and FIG. 2B is a side view. The solenoid-type power source breaker  107 A includes a shaft  111 , disposed on a base body  110  as shown in FIG. 2A, which is constrained with a lock  113  pressing down the shaft  111  to maintain a terminal  112   a  and a terminal  112   b  electrically continued in a connected state, before the circuit-cut signal is input to the solenoid-type power source breaker  107 A at the initial state. 
     At this initial state, electric current in the power supply circuit flows through the rout of the terminal  112   a  the shaft  111  the terminal  112   b , and the terminal  112   a  and the terminal  112   b  can supply a large current because of their having the multicontact spring structures. 
     When the circuit-cut signal is input, by supplying current to a solenoid  115  for drawing a plunger  116  in order to release the lock  113  in a linked state with the shaft  111 , pushing forward the shaft  111  by means of pushing force provided by a release spring  114  to make the terminal  112   a  isolated from the terminal  112   b , finally making the terminal  112   a  electrically open off from the terminal  112   b  to stop supplying power from the battery  101  to each load  102 - 104  etc. 
     However, in the conventional structure shown in FIG. 2, once an impulse is applied to the shaft  111  in the axial direction shown as an arrow A in the figure, the plunger  116  of the solenoid  115  is liable to malfunction to draw a lever  118 , and the malfunction may result in a problem of releasing the lock  113  out of a linked state with the shaft  111 . There has been also a problem that a need of miniaturization cannot have been coped with due to the use of the solenoid  115 . 
     SUMMARY OF THE INVENTION 
     The present invention, in consideration of the situation described above, aims to provide a power source breaker which can forcedly and surely isolate a power supply circuit in case of abnormalities such as short circuiting of a wire harness, collision of road vehicles, and also has a structure suitable for miniaturizing itself. 
     In order to achieve the above object, in the present invention at the initial position where a pair of terminals intervened in a power supply circuit is set in a connected state, and a shaft  16  forcedly provided by a release spring  17  with pushing force for sliding movement of itself is linked with a lock  18  forcedly provided by a reset spring  19  with pushing force for constraining sliding movement of the shaft, and a pushing force of a linear actuator  25  is converted into a force in the direction for liberating the linkage with the lock against the reset spring by means of a lock operation plate  20  as a lock liberating means. 
     According to the present invention, only when the pushing force of the linear actuator  25  goes beyond the pushing force of the reset spring  19 , the lock liberating means is actuated, and it can be avoided that the lock may be liberated resulting in the sliding movement of the shaft. 
     In another embodiment of the present invention, a linear motor has an actuating reagent and an internal gas pressure is changed by vaporization or sublimation of the actuating reagent when the linear motor operates. Because of no adoption of any solenoid, the power source breaker can further be miniaturized, and that will be preferable in order to cut down manufacturing cost. 
     Further, according to the present invention, since the shaft can be reset immediately after an operation of the shaft, it is easy to make the power supply circuit reset again at an electrically closed state. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     FIG. 1 is a systematic diagram showing an example of an electronic automobile parts system to which a conventional power source breaker is applied. 
     FIG. 2 is a diagram showing an example of a conventional power source breaker. FIG. 2A is the top view and FIG. 2B is the side view. 
     FIG. 3 is a systematic diagram showing an embodiment of an electronic parts system to which a power source breaker according to the present invention is applied. 
     FIG. 4 is a flowchart showing an isolation flow of the electronic automobile parts system in FIG.  3 . 
     FIG. 5 is a side sectional view of a main portion showing the structure of an embodiment of a power source breaker according to the present invention. 
     FIG. 6 is a perspective view showing the structure of the embodiment of the power source breaker shown in FIG.  5 . 
    
    
     DESCRIPTION OF THE PREFERRED EMBODIMENT 
     FIG. 3 is a systematic diagram showing an embodiment of an electronic automobile parts system to which a power source breaker according to the present invention is applied. 
     As shown in the figure, the electronic automobile parts system  1  includes a power supply circuit formed by connecting, with a wire harness  8  represented as a circuit  7 , each load such as a battery  2  of a road vehicle, a starter  3 , an alternator  4 , an ignition switch (IGN.SW)  5 , other loads  6 , and the power source breaker  9  according to the present invention intervened between a circuit  30  connected to the battery and the circuit  7 . Further, both an abnormality detecting sensor  10  such as a acceleration sensor and a power source controller  11  for isolating the power source according to the detected abnormality like an impulse etc. are used to operate the power source breaker  9 . The abnormality detecting sensor detects abnormalities like a collision and a fall as a sudden change of acceleration or occurrence of an impulse, an impulsive sound, an electromagnetic wave, etc., and transmits the occurrence of the abnormalities to the power source controller by means of an electric signal or an optical signal, and moreover a plurality of detecting means or judging means may be used in conjunction with each other. 
     The output  39  of the controller may be utilized to operate a safety equipment like a air bag, an alarm system, or a report system. A hazard  12 , a telephone (PHONE)  13 , and a door lock (D/L)  14 , are some examples of the system members which need not to be isolated from the power supply circuit by the power source breaker  9 , and are supplied with power from the battery through a circuit  31 . 
     As shown in the isolation flow of FIG. 4, when a road vehicle collides with a body like a preceding vehicle for example, the sensor  10  outputs an impulse signal to the power source controller  11  (step ST 1 ), and then a circuit-cut signal is generated at the power source controller  11  and the circuit-cut signal generated is output to the power source breaker  9  (step ST 2 ). 
     Consequently, the power source breaker  9  can isolate the power supply circuit and stop supplying power from the battery  2  to each load such as the starter  3 , the alternator  4 , the ignition switch (IGN.SW)  5  as will be described below on the basis of FIG.  3 -FIG. 6 (step ST 3 ). 
     FIG. 5 is a side sectional view of a main portion showing the structure of an embodiment of a power source breaker  9  relating to the present invention. FIG. 6 is a diagram of the power source breaker  9 , and FIG. 6A of the figure is a perspective view showing the initial state before liberation of a lock, and FIG. 6B of the figure is a perspective view of a main portion showing a state after liberation of the lock. 
     The gas-expansion-type power source breaker  9  has a pair of terminals  15   a ,  15   b  intervened in a power supply circuit connecting a battery of a road vehicle to each load disposed at each portion of the road vehicle. Further, an electrically conductive shaft  16  is disposed on a base body, and at the initial state (the state shown in FIG. 5) before the operation of the shaft  16  to which pushing force is forcedly provided by a release spring  17  in order to make the shaft move sliding along the arrangement direction (Z) of each terminal  15   a ,  15   b , and an end portion of the shaft  16  is linked with a lock  18  to constrain the sliding movement of the shaft  16 . At this state, each of the terminals  15   a ,  15   b  is set in an electrically connected state. 
     Due to the situation, an electric current of the power supply circuit flows through the terminal  15   a , the shaft  16 , and the terminal  15   b , and further a large electric current can flow through the terminals  15   a ,  15   b  owing to their multi-contact spring structure. 
     The lock  18  for constraining movement of the shaft  16  is disposed movably in a direction at a prescribed angle to the sliding direction Z, and is forcedly provided by a spring  19  with pushing force for constraining movement of the shaft  16  to establish in a locked state. Consequently, once the lock  18  is liberated from the linked state with the shaft  16 , the shaft  16  is pushed forwards (A1 direction shown by the arrow) by means of pushing force forcedly provided by the release spring  17 , and each of the terminals  15   a ,  15   b  is set in an isolated state with each other resulting in isolation of a circuit  30  from a circuit  7 . 
     A piston  21  of a linear actuator  25  is connected to the lock  18  via a lock operation plate  20 , and a reverse pushing(X +  direction) force beyond the pushing(X −  direction) force of the reset spring  19  is forcedly provided to the piston  21  by means of vaporization or sublimation of a gaseous actuating reagent  23  contained in an igniter  22 . Namely, once a circuit-cut signal is applied to the igniter  22 , the gaseous actuating reagent promptly vaporizes or sublimates, and the piston  21  generates a prescribed pushing force through a sudden increase of an internal pressure of the actuator accompanied by the generation of gases generated by vaporization or sublimation of the gaseous actuating reagent  23 . The pushing force is converted into the force which acts in such a direction as to liberate the lock  18  with the lock operation plate and is then transmitted to the lock. Consequently, the lock operates owing to the pushing force of the piston  21  beyond the pushing force of the spring  19 , and the lock  18  is forcedly released from the shaft  16 . The lock operation plate  20  is mechanically connected to both the linear actuator and the lock, and such a structure can be adopted as to convert the pushing force of the linear actuator into the force which acts in order to liberate the linked state of the lock with the shaft. 
     Since the lock  18  can reset the shaft  16  through returning the shaft to the initial linked state by means of the pushing force provided by the reset spring  19 , it can be easily done that the shaft  16  is reset at the initial position promptly after the operation of the shaft  16  and the power supply circuit is again set in the electrically closed state. 
     Thus, the power source breaker  9  according to the present invention has such a structure that it operates only when the pushing force of the piston  21  goes beyond the pushing force of the spring  19 , and the lock  18  is forcedly released from the shaft  16 , and that the lock  18  is connected in one body with the linear actuator  25  via the lock operation plate  20 , and therefore the power supply circuit can be isolated forcedly and surely only in case of abnormalities such as short-circuiting of a wire harness, collision of road vehicles. Since no solenoid is adopted as the lock liberating means, a requirement for further miniaturization of power source breakers of this kind can be coped with, and that is much preferable for cutting down a manufacturing cost. 
     Although the structure wherein the pushing force is generated by a pressure increase due to vaporization or sublimation of the gaseous actuating reagent is adopted for the linear actuator in the present embodiment, any other structure, wherein at least a linear driving force can be generated by pushing force for a prescribed duration, can be adopted, and for example, the piston can be actuated by means of a compressed gas supplied through controlling with an electromagnetic valve. Besides, a rotary motion may be converted into a linear motion by means of a mechanical converter such as a gear system, a lever. In this case, the mechanical converter has a function to convert rotating torque into linear force. 
     According to the present invention, at the initial position where a pair of terminals intervened in a power supply circuit is set in a connected state, and a shaft forcedly provided by a release spring with a pushing force for sliding movement of itself is linked with a lock forcedly provided by a reset spring with a pushing force for constraining a sliding movement of the shaft, and a pushing force of a linear actuator is converted into a force in the direction for liberating the linkage with the lock against the reset spring as a lock liberating means. Consequently, only when the pushing force of the linear actuator goes beyond the pushing force of the reset spring, the lock liberating means may be actuated, and it can be avoided that the lock may be liberated resulting in sliding movement of the shaft. 
     Since no solenoid is adopted as the lock liberating means, a requirement for further miniaturization of power source breakers of this kind can be coped with, and that is much preferable for cutting down a manufacturing cost.