Patent Application
20100026426
The present invention relates to an impact solenoid assembly for an electrical receptacle. More particularly, the present invention relates to a resilient member that spaces an armature from a latch of an impact solenoid assembly. Still more particularly, the present invention relates to a resilient member passing through a plunger to space an armature from a latch of an impact solenoid assembly, thereby increasing the momentum of the armature when activated and providing an impact solenoid assembly installable in any orientation.
Fault interrupting devices are designed to trip in response to the detection of a fault condition at an AC load. The fault condition can result when a person comes into contact with the line side of the AC load and an earth ground, a situation which can result in serious injury. A ground fault circuit interrupter (GFCI) detects this condition by using a sense transformer to detect an imbalance between the currents flowing in the line and neutral conductors of the AC supply, as will occur when some of the current on the line side is being diverted to ground. When such an imbalance is detected, a relay or circuit breaker within the GFCI device is immediately tripped to an open condition, thereby removing all power from the load.
Many types of GFCI devices are capable of being tripped not only by contact between the line side of the AC load and ground, but also by a connection between the neutral side of the AC load and ground. The latter type of connection, which may result from a defective load or from improper wiring, is potentially dangerous because it can prevent a conventional GFCI device from tripping at the required threshold level of differential current when a line-to-ground fault occurs.
A ground fault is not the only class of potentially dangerous abnormal operating conditions. Another type of undesirable operating condition occurs when an electrical spark jumps between two conductors or from one conductor to ground, which is also known as an arcing path. This spark represents an electrical discharge through the air and is objectionable because heat is produced as an unintentional by-product of the arcing. Such arcing faults are a leading cause of electrical fires.
Arcing faults can occur in the same places that ground faults occur; in fact, a ground fault would be called an arcing fault if it resulted in an electrical discharge, or spark, across an air gap. A device known as an arc fault circuit interrupter (AFCI) can prevent many classes of arcing faults. Both GFCIs and AFCIs are referred to as fault protection devices.
Solenoid assemblies in existing fault protection devices use a solenoid to drive an armature against a plunger to release a latch. The armature abuts the plunger such that the solenoid must drive both the armature and the plunger toward the latch. Thus, when the solenoid is activated, a large amount of activating force is required to drive both the armature and the plunger toward the latch. Furthermore, the activating force must overcome frictional forces.
Thus, there is a continuing need to provide an improved impact solenoid assembly for an electrical receptacle.
Accordingly, it is a primary objective of the present invention to provide an improved impact solenoid assembly for an electrical receptacle.
A further objective of the present invention is to provide an improved impact solenoid assembly that spaces an armature from a plunger to increase the impact force against a latch.
A still further objective of the present invention is to provide a resilient member for spacing the armature from the latch.
The foregoing objectives are basically attained by an electrical receptacle having an impact solenoid assembly. An armature has first and second ends. A resilient member is disposed between a latch and the second end of the armature. The resilient member spaces the armature from the latch. A plunger is disposed between the latch and the second end of the armature.
The foregoing objectives are also basically attained by an impact solenoid assembly for an electrical receptacle. A latch has first and second surfaces. An armature has first and second ends. A plunger is disposed between the latch and the second end of the armature. The plunger has a passageway extending from a first end to a second end of the plunger. A first spring is disposed between the first surface of the latch and the second end of the armature and passes through the passageway in the plunger. The resilient member spaces the armature from the latch. A second spring abuts the second surface of the latch.
Other objects, advantages and salient features of the invention will become apparent from the following detailed description, which, taken in conjunction with the annexed drawings, discloses a preferred embodiment of the invention.
As used in this application, the terms “front,” “rear,” “upper,” “lower,” “upwardly,” “downwardly,” and other orientational descriptors are intended to facilitate the description of the tamper resistant electrical receptacle, and are not intended to limit the structure of the tamper resistant electrical receptacle to any particular position or orientation.
The above aspects and features of the present invention will be more apparent from the description for an exemplary embodiment of the present invention taken with reference to the accompanying drawings, in which:
Throughout the drawings, like reference numerals will be understood to refer to like parts, components and structures.
As shown in
A test button 30 extends through opening 32 in the cover portion 14 of the housing 12. The test button 30 is used to activate a test operation that tests the operation of the circuit interrupting portion disposed in the GFCI device 10. The circuit interrupting portion is used to break electrical continuity in one of the conductive paths between the line and load side of the GFCI device 10. A reset button 34 extends through opening 36 in the cover portion 14 of the housing 12. The reset button 34 is used to activate a reset operation, which reestablishes electrical continuity in the open conductive paths.
The rear portion 16 has four screws, only two of which are shown in
An armature 61 is disposed within a solenoid 60, as shown in
A latch member 51 is disposed adjacent the solenoid 60 in the electrical receptacle 10, as shown in
A plunger 71 is disposed in the axial bore 59 of the solenoid 60 between the latch 51 and the armature 61, as shown in
A resilient member 81, such as a helical spring, is disposed between the latch 51 and the armature 61. Preferably, a first end 82 of the resilient member 81 abuts the first surface 52 of the latch 51 and a second end 83 abuts the second end 63 of the armature 61, and the resilient member 81 passes through the passageway 75 in the plunger 71. The resilient member 81 biases the armature 61 from the latch 51 when the electrical device is under normal operating conditions, as shown in
A reset button 91 is connected to a second end 92 of a shaft 93. A first end 94 of the shaft 93 is adapted to be releasably connected to the latch 51, as shown in
A spring 85 is disposed between a latch housing 97 and the second surface 53 of the latch 51. The spring constant of the spring 85 is preferably greater than the spring constant of the resilient member 81, thereby biasing the latch 51 toward the plunger 71 and preventing the armature 61 and plunger 71 from moving the latch 51. The shaft 93 is adapted to move axially through a bore 98 in the latch housing 97, as shown in
When the electrical device 10 is initially installed, the reset button 91 is in an outward position, as shown in
The reset button 91 and shaft 93 are then pushed inwardly (toward the rear portion 16) such that the shoulders 95 of the shaft 93 engage the opening 55 in the latch 51. The spring 96 then causes the shaft 93 to pull the latch housing 97 and the latch 51 upward until the latch housing engages an interior portion of the barrier 15, as shown in
When the solenoid 60 is triggered, the solenoid 60 magnetically drives the armature 61 toward the plunger 71. The armature 61 strikes the plunger 71, and both the armature and plunger move toward the latch 51. The armature and plunger strike the second surface 52 of the latch 51, thereby overcoming the spring 85 and moving the latch 51 toward the latch housing 97.
The movement of the latch 51 causes the opening 55 to move to the left, as shown in
Depending on the orientation of the electrical device 10, momentum is created in the armature 61 due to the gap between the armature 61 and the latch 51. The armature 61 and the plunger 71 strike the latch 51, thereby unlocking the latch 51 from the shaft 93 of the reset button 91.
The air gap between the latch 51 and the armature 61 allows the armature 61 to move freely or against a very small resistive force. By allowing the armature 61 to move freely, the armature 61 is able to increase its velocity and create linear momentum, which is the product of mass and velocity. In the absence of the resilient member 81, there would be no air gap between the armature 61 and the latch 51. The value of the velocity of the armature 61 when the solenoid is activated would be zero and there would be no linear momentum created. Thus, by spacing the armature 61 from the latch 51 with a resilient member 81 a more effective and efficient impact solenoid assembly is provided.
While one advantageous embodiment has been chosen to illustrate the invention, it will be understood by those skilled in the art that various changes and modifications may be made therein without departing from the scope of the invention as defined in the appended claims.
