Electricity: circuit makers and breakers – Special application – Frangible or destructible type
Reexamination Certificate
2001-09-19
2003-10-21
Friedhofer, Michael (Department: 2832)
Electricity: circuit makers and breakers
Special application
Frangible or destructible type
C200S05200R, C200S061040
Reexamination Certificate
active
06635834
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of Invention
This invention relates to delaying closure of an electrical circuit to delay activation of an electrically powered device until its activation is desired.
2. Prior Art
Colon cancer is the second leading cause of death in humans. It is curable if it is detected early. The current method of choice for early detection of colon cancer is a colonoscopy. Unfortunately, for many, colonoscopy is an expensive and uncomfortable procedure. Also, there is a risk that the colon will be punctured during the procedure. Consequently, many people opt not to have or postpone having the procedure. As a result, thousands of people die every year because they do not get a colonoscopy.
A less intrusive and cheaper method for early detection of cancer has been developed. It is described in U.S. Pat. No. 5,604,531 to Iddan, et al., Feb. 18, 1997 In this method, a small endoscopic capsule is swallowed. The capsule contains, inter alia, a means for illumination, a video camera, a lens arrangement and a transmitter. The capsule travels through the body, taking pictures along the alimentary canal and transmitting them to a receiver attached to a belt worn by the patient. Patients are permitted to move around normally during the approximate 8 hour procedure. Since the device must be small enough to be swallowed, the size of its power source, a battery, and the amount of power it can provide are severely limited. Further, the capsule must be turned on before it is swallowed. Therefore, the principal disadvantage of this device is that the power source is depleted before it completes an investigation of the small intestine and colon. Consequently, the device is unable to investigate for cancer and other abnormalities in these parts of the body. My invention solves this problem by delaying activation of devices, such as this capsule, until needed.
There are several patents covering methods used to delay activation of electrically powered devices until they are needed. U.S. Pat. No. 5,057,824 to Stokes, Jul. 30, 1990 uses a normally closed switch held open by a removable spacer. It is designed to be used in security systems to conserve battery power until the device is ready for use. Upon manual removal of the spacer the switch closes and power is supplied. The principle disadvantage of this method is that it must be activated manually, and thus cannot be activated while in an environment that is not directly accessible, such as the human alimentary canal. If the removable spacer method were used to delay activation of the endoscopic capsule in U.S. Pat. No. 5,604,531, it would need to be activated prior to being swallowed; accordingly, the device would still run out of power prior to completing an investigation of the small intestine and colon.
U.S. Pat. No. 4,278,077 to Mizumoto, Jul. 14, 1981 uses an induction system to energize an electromagnetic field in a coil around a permanent magnet located in the device. This method energizes the device when it is needed. The principal disadvantage of this device is that it requires the patient to remain in a stationary position during the entire 8 hour process. Furthermore, this method cannot be used to energize the endoscopic capsule in U.S. Pat. No. 5,604,531 to Iddan, et al., Feb. 18, 1997 due to size constraints.
SUMMARY OF THE INVENTION
The present invention is a system and method to delay closure of an electrical circuit of a battery-powered electrical device, intended to operate remotely in an environment in which the pH value changes from one value to another. More specifically, two electrical contacts, at least one being movable, of a normally closed electrical circuit, connecting a battery in series with a battery-powered electrical device, are separated by a material that holds the circuit open until the device is exposed to an environment having a specified pH value. Exposure of the material to an environment having that specified pH value causes the material to dissolve. The dissolving of the material causes the circuit to close, energizing the device.
Accordingly, several objects and advantages of my invention are to provide a means to delay activation of a battery-powered device by holding it in a deactivated condition until ready for use. Another object is to provide a means by which an electrical device can be self-activated at a specific point within an environment that is difficult to access, such as the human alimentary canal.
Another object is to use the pH value of an environment to dissolve a pH-sensitive material separating electrical contacts to dissolve the material and activate a battery-powered electrical device.
Further objects and advantages of my invention will become apparent from review of the process flow chart, drawings and description of a preferred embodiment.
BRIEF DESCRIPTION OF THE DRAWINGS
The present invention will be understood more fully from the following description taken in conjunction with the drawings in which:
FIG. 1
shows the normally closed switch, according to the present invention, held open by a pH-sensitive material and connected in series between the battery and electrical circuitry of a swallowable endoscopic capsule;
FIG. 2
shows the normally closed switch, according to the present invention, held open by the pH-sensitive material separating the contacts; A system and method are provided to delay closure of an electrical circuit of a battery-powered electrical device, intended to operate remotely in an environment in which the pH value changes from one value to another. More specifically, two electrical contacts, at least one being movable, of a normally closed electrical circuit, connecting a battery in series with a battery-powered electrical device, are separated by a material that holds the circuit open until the device is exposed to an environment having a specified pH value. Exposure of the material to an environment having that specified pH value causes the material to dissolve. The dissolving of the material causes the circuit to close, energizing the device.
FIG. 3
shows the normally closed switch, according to the present invention, after the pH-sensitive material has dissolved; and
FIG. 4
is a process flow chart for the present invention.
REFERENCES:
patent: 3997886 (1976-12-01), Lerner
patent: 4313042 (1982-01-01), Ehrhart
patent: 5846744 (1998-12-01), Athey et al.
patent: 6330465 (2001-12-01), Huyberechts et al.
Chalfie Edward J.
Friedhofer Michael
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