Electric heating – Heating devices – With power supply and voltage or current regulation or...
Reexamination Certificate
1999-11-01
2001-12-04
Hoang, Tu Ba (Department: 3742)
Electric heating
Heating devices
With power supply and voltage or current regulation or...
C219S489000, C219S528000
Reexamination Certificate
active
06326596
ABSTRACT:
TECHNICAL FIELD
The present invention relates to systems and methods for controlling voltage and power applied to a resistor array, and in particular to a resistor array capable of being used with a heating pad, such as that used for medical and/or therapeutic purposes.
BACKGROUND ART
Heating pads have been in use for some time for medical and/or therapeutic purposes. Specifically, the heat supplied from the pads have been used to warm body parts, and in particular muscle areas, to relieve such areas from the aches and pains associated therewith.
To maintain a substantially constant heat level over an extended period of time, heating pads have utilized electrical power to generate a source of heat by way of a resistor array. In some designs, the heating pads are provided with mechanisms for controlling (hereinafter “control units”) the amount of power to the resistor array, so as to vary the level of heat generated. With such control units, the duration of power supplied to the heating pad is often continuous, thus resulting in a continuous generation of heat by the pad. To avoid continuous generation of heat, or at least until the heating pad is disconnected from a power source, such as an outlet, some control units have employed the use of a timer to cut off the supply of power to the resistor array, after a preset amount of time. In this manner, the control unit can determine the duration over which heat is generated from the pad.
Despite having a timer, there are some disadvantages associated with currently available heating pads. Specifically, the timers available with current heating pads are often designed with just one setting, usually for a duration of about sixty minutes. Thus, should the heat pad user wishes to stop using the heating pad prior to the expiration of the preset time period, the user may be inconvenienced by being forced to unplug the electrical chord which connects the heating pad to an electrical outlet in order to stop the supply of power to the heating pad. Subsequently, to initiate another use session, the user must remember to re-plug the electrical chord into the outlet prior to getting comfortable. Otherwise, the user must move from his comfortable arrangement to plug the electrical chord into the outlet.
The design of existing control units may also create potential hazards. In particular, should the user neglect to unplug the electrical chord from the outlet prior to moving away from the heating pad area for an extended period of time, the continuous supply of power to the heating pad, or at least for the duration of the timer period, without any supervision from the user may cause an accidental fire to be started. Moreover, the continuous supply of power to the heating pad without the use of same by the user would result in a waste of energy and thus money.
Accordingly, it would be desirable to provide a control unit which permits the user to vary the time period during which power is supplied to the heating pad. Furthermore, it would be desirable to provide the user with an option for a time period shorter than that currently available, so as to avoid any potential hazards, waste of energy, or frequent plugging and unplugging of the electrical chord from the outlet.
SUMMARY OF THE INVENTION
The present invention, in accordance with one embodiment, is directed to a system for controlling power to a resistor array in a heating pad. The system includes a power supply for connection to a power source and a resistor array positioned within a heating pad for generating heat based on a selected heat level. The system also includes a control unit connecting the power supply to the resistor array. The control unit, in an embodiment, includes a timer device for generating one of an initial set time period and a shortened time period during either of which period power is supplied to the system. The timer device is designed so that at the expiration of the initial set time period or the shortened time period, the supply of power from the power supply is automatically terminated. In connection with the timer device, a mechanism is provided which can initiate the shortened time period in place of the initial set time period. The mechanism may be used to reset the shortened time period to its full duration, after an elapsed period, each time the mechanism is activated. The control unit further includes an input mechanism for selecting an amount of heat to be output by the heating pad. The input mechanism for selecting the amount of heat can be a plurality of buttons, each representing a different level of heat output, or alternatively be a sliding element for selection of different levels of heat output. When the input mechanism is a sliding element, the control unit may be provided with a mechanism to initiate the supply of power to the system. The control unit preferably includes a microprocessor for controlling the duration and supply of power to the resistor array.
REFERENCES:
patent: 4158432 (1979-06-01), Van Bavel
patent: 4744359 (1988-05-01), Hatta et al.
patent: 5079410 (1992-01-01), Payne et al.
patent: 5079784 (1992-01-01), Rist et al.
patent: 5420397 (1995-05-01), Weiss et al.
patent: 5802957 (1998-09-01), Wanat et al.
patent: 6153858 (2000-11-01), Barnes et al.
Carr Sheldon M.
O'Leary Kenneth P.
Cara Incorporated
Foley Hoag & Eliot LLP
Hoang Tu Ba
LandOfFree
Systems and methods for controlling power applied to a... does not yet have a rating. At this time, there are no reviews or comments for this patent.
If you have personal experience with Systems and methods for controlling power applied to a..., we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Systems and methods for controlling power applied to a... will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-2579453