Electric resistance heating devices – Heating devices – Concentrated heated air stream
Reexamination Certificate
1999-02-03
2001-02-13
Jeffery, John A. (Department: 3742)
Electric resistance heating devices
Heating devices
Concentrated heated air stream
C034S097000
Reexamination Certificate
active
06188837
ABSTRACT:
FIELD OF THE INVENTION
The present invention relates to hand-held hair dryers and, more particularly, to hand-held hair dryers with a built-in retractable power cord reel.
BACKGROUND OF THE INVENTION AND PRIOR ART
Hand-held hair dryers are probably one of the most widely used electrical appliances known to-date and they can be found in almost every home in the developed world. Because of its usually high power consumption rate of 1-2 kW, a hair dryer is usually equipped with a flexible power cord for connection to the mains power supply. While a long power cord is desirable to provide high mobility so that the hair dryer can be used at a distance from the mains outlet, an excessive length of un-restrained power cord accessible to young children is however already known to be a source of potential domestic hazards.
Furthermore, it is well known that the power cords from adjacently stored corded appliances tend to entangle together and it would be difficult to separate the entangled power cords. As there are ever-increasing varieties of corded electrical appliances, this is an annoying phenomenon which a designer of electric appliances need to consider in the development of new appliances.
To alleviate the aforementioned problems, it is desirable that a built-in power cord storage device is provided on a hair dryer so that the excessive length of power cord can be restrained and stored on the dryer, especially when the dryer is not in use. In addition, a desirable power cord storage device should preferably provide a controlled release of the stored power cord so that only a desired length of cord is released while the remaining portion is kept on the dryer.
Portable hair dryers with retractable power cord storage devices are already known. U.S. Pat. Nos. 4,528,440 and 5,784,800 issued respectively to Ishihara and Santhouse et al. represent better known types of them.
The former type is characterized by a laterally mounted power cord storage device which results in a lack of symmetry about the vertical plane. This lack of symmetry leads to a two-fold disadvantage—a user would have to hold the dryer firmly upright to prevent tilting and that left- and right-hand versions would have to be supplied to better suit different users.
The latter type is characterized by a cord storage reel which is mounted in coaxial alignment with the elongate barrel inside the housing of the dryer. A main disadvantage of this latter arrangement is that many unsightly air vents are required on the sides of the hair dryer in order to provide alternative ventilation paths when the conventional air-ventilation paths, formed between ventilation holes at the rear of the hair dryer and the barrel exit, are blocked by the power cord being carried on the cord reel. The presence of such additional ventilation holes also means that water drops can get in more easily and cause electric faults.
As a conventional hair dryer is usually provided with electric coil heaters which are turned on or off by a toggle switch, potential fire hazards are often a major concern for families with young children who may accidentally or deliberately turn hair dryers on and leave them on. This is especially dangerous when the whole length of power cord is being stored on the cord reel inside the barrel, thereby substantially blocking the ventilating paths.
Furthermore, the affinity of blown dried hair for dust is another known shortcoming of conventional portable hair dryers with which designers of hair dryers need to be concerned if a more useful appliance is to be made available to the public.
OBJECT OF THE INVENTION
It is therefore an object of the present invention to provide an improved hair dryer with a built-in cord storage device which is substantially symmetrical about the vertical plane during use but alleviating the need of extra unsightly ventilating vents on the sides to provide secondary air-passageway to prevent overheating. It is another object of this invention to provide a hair dryer with means to alleviate fire hazards which may be caused by inadvertently or deliberately leaving a hair dryer on while un-attended. It is a further objective of the present invention to alleviate the known problem of dust affinity for blown dried hair. As a minimum, it is an object of the present invention to provide the public with an useful choice.
SUMMARY OF THE INVENTION
Accordingly, there is provided a portable hair dryer having a main housing with a length of flexible power cord in which the main housing comprises a barrel portion and a handle portion. Inside the barrel portion there are provided a motor driven fan and a power cord storage reel. The barrel portion has at least one aperture disposed at a rear end through which external air enters said barrel and a nozzle disposed at a front end through which air leaves said barrel; the power cord reel is disposed intermediate of said front and rear ends with a median plane substantially normal to the axis of said barrel; the hair dryer has a control means operable by the amount of flexible power cord being carried on said power cord reel to turn off the power supply to at least a portion of said hair dryer when the length of power cord being carried on said cord reel exceeds a predetermined amount.
Preferably, the control means of the aforementioned hair dryer comprises a sensing means and a switching means, said sensing means detects the amount of power cord being carried on said power cord reel and sends out a corresponding signal, said switching means receives said corresponding signal from said sensing means and will turn off power supply to at least a portion of said hair dryer when said corresponding signal reaches a pre-determined threshold.
As shown in the preferred embodiment, the sensing means preferably comprises an infra-red emitter and receiver pair, said emitter and receiver pair is normally in communication and is disposed diametrically across said power cord reel, said receiver is adapted to cause power supply to said hair dryer to be turned off when the communication between said emitter and receiver is sufficiently blocked by said power cord.
Preferably, the hair dryer further comprises a hand sensor for detecting the presence of a hand on the handle portion, wherein said hand sensor gives out a corresponding signal to turn said hair dryer off when the hair dryer is in operation and no hand is detected.
To avoid the problem of dust affinity for blown dried hair, it is preferred that the hair dryer is also provided with an ionizing means for ionizing the air surrounding the hair to be dried and neutralizes the electronic charge remaining on said hair so that it is less dust attractive.
According to a second aspect of this invention, there is provided a portable hair dryer having a main housing with a length of flexible power cord in which the main housing comprises a barrel portion and a handle portion and inside said barrel portion there are provided a motor driven fan, a power cord storage reel. The barrel portion has at least one aperture disposed at a rear end through which external air enters said barrel and a nozzle disposed at a front end through which air leaves said barrel; the handle portion is provided with a hand sensing means which detects the presence of a hand on the handle portion and gives out a corresponding signal when said hair dryer is in operation and no hand is detected at the handle portion.
REFERENCES:
patent: 2015982 (1935-10-01), Witzel
patent: 3135859 (1964-06-01), Mitter
patent: 3949487 (1976-04-01), Bartram et al.
patent: 4293759 (1981-10-01), Higgins
patent: 4528440 (1985-07-01), Ishihara
patent: 4658116 (1987-04-01), Tsang et al.
patent: 5351417 (1994-10-01), Rubin
patent: 5784800 (1998-07-01), Santhouse et al.
patent: 459507 (1968-09-01), None
patent: 3728885 (1989-03-01), None
patent: 4429112 (1995-01-01), None
patent: 38452 (1981-10-01), None
patent: 2055573 (1981-03-01), None
patent: 4-105628 (1992-04-01), None
patent: 5-291926 (1993-11-01), None
patent: 7-171079 (1995-07-01), None
Burns Doane Swecker & Mathis L.L.P.
China Pacific Trade Ltd.
Jeffery John A.
LandOfFree
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