US 3706008 A
Description (OCR text may contain errors)
Dec. 12, 1972 F. B. KREMER 3,706,008
BODY CURRENT ACTIVATED CIRCUIT BREAKER Filed Feb. 5, 1972 22 32 26 e F|G. I
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84 FIST/1W 78 M 76 FIG. 3 L so; ONE sHoT L n TRANSFORMER 6 8 SCHMITT TRIGGER ('H) N SCHMITT TRIGGER R (-1) T E 64 R 66 3,706,008 BODY CURRENT ACTIVATED CIRCUIT BREAKER Frederic B. Kremer, 1600 Garrett Road, Apt. B-204, Upper Darby, Pa. 19082 Filed Feb. 3, 1972, Ser. No. 223,096 Int. Cl. H0211 3/16 US. Cl. 317-18 A 7 Claims ABSTRACT OF THE DISCLOSURE BACKGROUND OF THE INVENTION The present invention relates generally to the field of electrical interrupting devices, and more particularly is directed to a circuit breaker apparatus which is responsive to the undesired flow of current in a human body to automatically interrupt the power supply to an electrical appliance.
It is well known that electricity and the effects of electrical current passing through the body causes many deaths and injuries throughout the world. For example, the Statistical Abstract of the United States, 1970 edition lists the number of accidental deaths in the United States caused by electrical current for the years 1960, 1965 and 1967 as 989, 1,071 and 992 deaths respectively.
Various effects of electrical current upon the human body have been noted by prior workers in the field. Electrical current, for example, has been known to temporarily or permanently cause breathing to stop. Permanent or temporary damage to the nervous system has been known to occur. Cardiac arrest is possible. Burns throughout the entire range from minor to fatal are readily documented. Ventricular fibrillation, a condition where the heart simply vibrates and loses its normal pumping action, may occur. Under circumstances death usually occurs within a period of two minutes. Inasmuch as defibrillators are rarely available at the scene of an accident. Ventricular fibrillations is almost always fatal and it is believed to be the most common cause of death due to electrical shock.
It has been observed that damage to the human body is caused by the excessive flow of current and that such damage is not actually a function of the voltage. When an electrical current passes through a body it produces a corresponding voltage. Because the resistance of the body to the flow of electrical current varies, the voltage also will correspondingly vary and so, the same current will not always produce exactly the same voltage. In any event, a dangerous rise in the flow of current will also cause an increase in the ambient voltage. Small electrical currents are always present in living bodies due to the functions of the body and in some instances, due also to radiation from outside sources.
Dalziel, in a paper entitled, Reevaluation of Lethal Electric Currents, IEEE Transactions on Industry and General Applications, vol. IGA-4, No. 5, September/ October 1963, has approximated the level at which current is considered to be dangerous at 16 ma. for men and 10.5 for women. He refers to these as let-go currents because currents above this level tend to freeze the victims United States Patent 3,706,008 Patented Dec. 12, 1972 muscles so that he cannot let go of the source of the current. Kouwenhoven supports these findings in a paper entitled A-C Shocks of Varying Parameters Affecting the Heart, Communications and Electronics, May 1959 where he states that the limit of safe current is 15 ma.
When dealing with electric shocks, time is of the utmost importance. In general, the proposition that a shock of short duration is less dangerous then a shock of the same magnitude of longer duration was substantiated by L. P. 'Ferris, Etfects of Electric Shock on the Heart, Electrical Engineering, May 1936. Kouwenhovens research illustrates specific levels and durations. Dalziel has formulated an electrocution equation which further illustrates this time-death relationship. See Lethal Electric Currents, IEEE Spectrum,, February 1969.
SUMMARY OF THE INVENTION The present invention relates generally to the field of safety devices in the electrical art, and more particularly is concerned with a circuit breaker which is interposed between an electrical appliance and its user to automatically interrupt the current supply to the appliance immediately upon the detection of an increase in voltage in the body of the user.
A circuit breaker device is provided with an outlet to supply line voltage to an electrical appliance such as a hand power tool, electrical testing gear, or electrical medical treatment device, industrial machines, electrically operated amusement devices and the like. A pair of electrodes capable of sensing an increase in body voltage extend from the circuit breaker and are placed remotely upon the body of the user, for example, one electrode on each arm.
The device is provided with internal circuitry capable of immediately interrupting the flow of current to the electrical appliance in response to the detection of increased body voltage at the electrodes above a predetermnid level. Should the voltage across the two body electrodes exceed the predetermined level, the comparator circuit within the circuit breaker will send out either a plus or minus signal, depending on which electrode is at a higher voltage. If it is a positive voltage, the plus one Schmitt trigger will respond. If it is a negative voltage, the minus one Schmitt will respond and be inverted to a plus one signal. Via the or circuit, either of the two signals will activate the one shot circuit to send out a signal that is at an appropriate level to activate the latching relay. When the relay switches, it opens both leads to the line voltage, thereby interrupting the power supply to the electrical appliance and the devices circuitry, and holds that position until manually reset. If desired, the line voltage may be transformed and applied to an alerting light and a buzzer to give visual and audible warning signals.
It is an object of this invention to provide a novel body current activated circuit breaker of the type set forth.
It is another object of this invention to provide a novel body current activated circuit breaker capable of automatically and immediately interrupting the flow of current to an electrical appliance upon the detection of an increase in voltage across a body.
It is another object of the present invention to provide an improved body current activated circuit breaker that includes a pair of body contacting electrodes and necessary circuitry to interrupt the flow of electrical current to an electrical appliance automatically when the electrodes pick up an increase in the voltage across the body of the user.
It is another object of the present invention to provide a novel body current activated circuit breaker that is electrically interposed between an electrical appliance and its user and which is capable of interrupting the source of power to the electrical appliance should an increase in user body voltage be detected to prevent the danger of fatal shock to the user.
It is another object of the present invention to provide a novel body current activated circuit breaker that is in expensive in manufacture, rugged in construction and trouble free when in use.
Other objects and a fuller understanding of the invention will be had by referring to the following description and claims thereof, taken in conjunction with the accompanying drawings wherein like reference characters refer to similar parts throughout the several views and in which:
BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a perspective view of the device in use in conjunction with an electrical appliance such as a hand power drill.
FIG. 2 is a general block diagram showing the normal electrical connections to the body current actuated circuit breaker of the present invention.
FIG. 3 is a circuit equivalent block diagram showing the internal construction of the circuit breaker.
, FIG. 4 is an enlarged perspective view of an electrode for use in contacting a portion of the body of the user.
DESCRIPTION OF THE PREFERRED EMBODIMENTS OF THE INVENTION Although specific terms are used in the following description for the sake of clarity, these terms are intended to refer only to the particular structure of my invention selected for illustration in the drawings, and are not intended to limit or define the scope of the invention.
Referring now to the drawings, I show a circuit breaker device connected to a source of electrical power, for example, a common duplex wall receptacle 12 through a two cord power supply line 14. An electrical appliance, for example a hand power drill 16, connects to the circuit breaker 10 through its two wire power supply cord 18 in the usual manner. Extending from the circuit breaker device 10 are a pair of body contacting electrodes 20, 22 which are wired to the device 10 by their respective single wire conductors 24, 26. It will be understood that all of the wiring connections are well insulated in the usual manner to comply with all safety regulations, such as the National Electrical Code and the requirements of Underwriters Laboratories, Inc. In addition to the wiring connections illustrated, a third wire for grounding purposes may be employed in well known manner desired without interferring with the basic circuitry and operation of the device. The electrodes contact remote portions of the body of the user 28, for example, the upper arms 30, 32 for the body voltage monitoring purposes. The electrodes may encircle body portions as indicated in FIG. 1 or could be of the button type which may be in contact with the skin of the user.
As simply illustrated in FIG. 2, the two cord power supply 14 introduces live current to the circuit breaker 10 at the upper terminals 34, 36. The electrode conductors 24, 26 connect to the circuit breaker device 10 at the terminals 38, 40. Similarly, the two wire appliance power supply cord connects to the circuit breaker device 10 at the lower terminals 42, 44.
Referring now to FIG. 3, it will be seen that line power from the terminals 34, 36 is introduced to the double pole switch 46 by the power conductors 48, 50. This line power is conducted directly to the appliance terminals 42, 44 by the switch connected appliance conductors 52, 54.
It will be noted that under normal conditions of use, the double pole switch 46 remains in the first positions as illustrated to thereby direct line power directly to the appliance terminals 42, 44.
Should an increase in body voltage be picked up by the electrodes 20, 22 which is higher than a predetermined level, the increase voltage will be impressed across the electrode terminals 38, 40 by means of the electrode con- 4 doctors 24, 26 and carried to the comparator circuit 56 by the conductors 58, 60. The comparator circuit 56 will send out either a plus or minus signal depending on which electrode terminal 38, 40 is at a higher voltage. If it is a positive voltage, the plus one Schmitt trigger 62 will respond. If it is a negative voltage, the minus Schmitt trigger 64 will-respond. In the latter case, the inverter '66 serves to invert the signal to a plus one signal. The signals from either the plus one Schmitt trigger 62 or the minus one Schmitt trigger 64 are fed to the OR circuit 68 as is the output of the first transformer 70 which provides low voltage power for the OR circuit. The signal from either Schmitt trigger 62, 64 will set off the one shot circuit via the OR circuit 68. The one shot circuit 74 will send out a signal that is at an appropriate level to activate the coil 76 of the latching relay 72. This in turn opens the switch contacts 78, 80 to immediately deenergize the appliance conductors 52, 54.
The device is designed to hold the switch 46 open once the latching relay 72 has activated until it is manuallv re-set. In this manner, once an increase in voltage has been detected, power supply to the appliance 16 will be automatically cut off and power cannot be again supplied until conscious, manual effort is employed. If desired, a second transformer 82 can be wired to the off switch contacts 84, 86 in a manner to activate the transformer circuit when the switch 46 is opened to de-energize the appliance conductors 52, 54. A buzzer 88 and light 90 wire in parallel with the second transformer secondary windings to give audible and visible warning signals when the switch is tripped.
The body electrode 20 as set forth in FIG. 4 is illustrated with an elasticized band 92 of the size to encircle the wrist, ankle, or upper arm of the user 28. However, it will be appreciated that the body electrode could be of the skin contact type that simply aflixes to the skin in conventional manner. A conducting wire 94 is interwoven into the band 92 in a manner to permit expansion and contraction of the band 92 without damage to the wire 94. Portions of the wire 94 should contact the skin of the user in order to be immediately responsive to a rise in body voltage. Many suitable types of body electrodes are presently commercially available and any prior art electrode capable of responding instantly to a rise in voltage would be suitable for this purpose. The exact configuration of the electrodes 20, 22 is not of prime importance inasmuch as it is the function of detecting the rise in body voltage and not a particular design that is of interest. In any design, the conductors 24, 2'6 electrically interconnect with the respective electrode conductive wires 94 to carry the monitored rise in voltage to the circuit breaker terminals 38, 40.
In another embodiment of the invention, the body electrode could be connected to a small transmitter of the portable type and be conventionally wired to transmit a radio signal immediately upon detection of a rise in body voltage. A receiver responsive to the radio signal could be associated with the switch 46 through suitable relays of well known design to trip the switch to open the switch contacts 78, 80.
1. In a circuit breaker device which is responsive to the flow of current in a human body caused by the malfunction of an electrical appliance, the combination of (A) a switch housed within the circuit breaker device,
(1) said switch being movable from a first position to a second position:
(B) line power input means connecting the circuit breaker to a source of electrical power,
(1) said line power input means being connected (1) said appliance receptacle means receiving electrical energy from the line power input means when the switch is in its said first position to power an electrical appliance,
(2) said appliance means receiving no electrical energy when the switch is in its said second position to interrupt the supply of power to said electrical appliance; and
(D) electrode means detecting the flow of current in the human body caused by malfunction of the electrical' appliance,
(1) said electrode means functioning the said switch upon detection of the flow of current,
(2) said electrode means moving the switch from the first position to the second position to interrupt the flow of electrical energy to the appliance receptacle means upon detection of the flow of current.
2. The invention of claim 1 wherein said electrode means include at least two body contacting members.
3. The invention of claim 2 wherein the body contacting members contact the human body in locations remote from each other.
4. The invention of claim 3 wherein portions of the electrodes encircle parts of the human body.
5. The invention of claim 3 wherein portions of the electrodes are electrically conductive and portions of the electrodes are electrically nonconductive.
6. The invention of claim 2 wherein the body contacting members contact the skin of the said human body.
7. The invention of claim 1 wherein the electrode means include a radio signal transmitter which is activated by the flow of current in the human body and the said circuit breaker device includes a receiver responsive to signals generated by the said transmitter, said receiver activating the switch from its first position to its second position.
References Cited UNITED STATES PATENTS 3,171,062 2/1965 Rowe 317-18A 3,351,813 11/1967 Trout 317l8A JAMES D. TRAMMELL, Primary Examiner US. Cl. X.R. 1282.1 Z