DRYING APPARATUS
United States Patent 3643346
An improved electric hand dryer which provides a partially enclosed chamber within its housing so that the user's hands can be inserted into the chamber during the drying cycle. Warm dry air is directed in a circular flow path within the chamber so that a major portion of it is recirculated through the heater and dryer while it dries the user's hands on all sides so that the drying cycle and the power requirements of the apparatus are significantly reduced. The dryer can also be adapted for use as a face dryer, food warmer, hair dryer, and as a room heater, and as a clothes dryer.
US Patent References:
Hood for drying hair
Ducart - June 1936 - 2042592
Hand dryer
McLeckie - March 1948 - 2438762
Food warmer
Fox - November 1966 - 3288129
Fans of the cross-flow type
Laing - February 1967 - 3305164
ELECTRICALLY HEATED THAWING OVEN
Sauer - September 1969 - 3465124
Hood for drying hair
Ducart - June 1936 - 2042592
Hand dryer
McLeckie - March 1948 - 2438762
Food warmer
Fox - November 1966 - 3288129
Fans of the cross-flow type
Laing - February 1967 - 3305164
ELECTRICALLY HEATED THAWING OVEN
Sauer - September 1969 - 3465124
Application Number:
04/829005
Publication Date:
02/22/1972
Filing Date:
05/29/1969
View Patent Images:
Export Citation:
Assignee:
Lestron International Corporation (Jamacia, NY)
Primary Class:
Other Classes:
34/554, 219/400, 34/219, 392/381, 219/518, 34/212, 392/363
International Classes:
A47K10/48; A47K10/00; F26B19/00
Field of Search:
34/202,212,219,243 126/261 219/366-371,400
Primary Examiner:
Dority Jr., Carroll B.
Claims:
I claim
1. An electric hand drying apparatus for connection to an electrical power source comprising;
2. An electric hand drying apparatus for connection to an electrical power source comprising:
3. An electric hand drying apparatus for connection to an electrical power source comprising;
4. An electric hand drying apparatus for connection to an electric power source comprising;
5. The apparatus as recited in claim 4 wherein said cover is constructed from a transparent material.
6. The apparatus as recited in claim 1 wherein said means includes a trip lever disposed adjacent to the entrance of said second chamber adjacent to the front of said housing, and,
1. An electric hand drying apparatus for connection to an electrical power source comprising;
2. An electric hand drying apparatus for connection to an electrical power source comprising:
3. An electric hand drying apparatus for connection to an electrical power source comprising;
4. An electric hand drying apparatus for connection to an electric power source comprising;
5. The apparatus as recited in claim 4 wherein said cover is constructed from a transparent material.
6. The apparatus as recited in claim 1 wherein said means includes a trip lever disposed adjacent to the entrance of said second chamber adjacent to the front of said housing, and,
Description:
This invention relates to an improved electric drying apparatus for rapidly drying various articles.
More specifically, this invention relates to an electric hand dryer, which may also be easily adapted for use as a hair dryer, face dryer, food warmer, room heater, clothes dryer, and the like.
Conventional drying devices such as hand dryers generally consist of an air blower which directs a stream of air through electric heating elements before the air is dispersed from its outlet. The output nozzle directs the warm, dry air onto the hands of the user for a predetermined drying cycle. When the user's hands are placed in the path of the moving air emitted from the nozzle, only one side of the user's hands are dried at a time, and the user must rotate his hands in front of the dryer so that they will be completely dried during the running cycle of the apparatus. Moreover, the airstream tends to blow the water from the user's hands over his clothing. The water also drips onto the floor in front of the dryer while the hands are being dried. The airstream directed from the front of the conventional dryer also heats up the room so that after repeated usage, the room containing the conventional dryer becomes excessively heated. The conventional hand dryers are generally constructed for a single purpose only and are not readily adaptable for use as a hair and face dryer, food warmer, room heater and the like.
Accordingly, the present invention provides an improved electric drying apparatus which provides a partially enclosed chamber within its housing so that the user's hands can be inserted into this chamber during the drying cycle. Warm, dry air, which is directed in a circular flow path within the chamber of the apparatus, contacts the user's hands on all sides so that it is not necessary for the user to rotate his hands within the chamber of the apparatus. Moreover, the circular movement of the warm dry air within the chamber of the apparatus permits a major portion of the air to be recirculated through the blower of the dryer, and reheated, so that only a small portion of the dry air escapes from the chamber opening at the front of the apparatus. By recirculating the warm, dry air of the blower, it is possible to provide a hand dryer which is more efficient in operation, and which requires less electrical power and uses smaller components than conventional hand dryers. Moreover, since the warm, dry air is directed tin a circular flow, the air completely surrounds the user's hands so that they are dried in less time than ordinarily required by conventional hand dryers. The dryer also does not excessively heat the surrounding room or permit water to drip on the floor or the user's clothes. In other embodiments of the invention, modifications are provided which permit the drying apparatus to be utilized as a food warmer, hair dryer, face dryer, clothes dryer, room heater and the like.
It is therefore an object according to the present invention to provide a drying apparatus which is capable for use as an improved hand dryer as well as a variety of other drying applications.
It is another object according to the present invention to provide a drying apparatus when recycles a major portion of its output to perform a more efficient drying cycle.
It is still a further object according to the present invention to provide an electric hand dryer which is simple in design, easy to construct and reliable in operation.
Other objects and features of the present invention will become apparent from the following detailed description considered in connection with the accompanying drawings which disclose several embodiments of the present invention. It is to be understood, however, that the drawings are designed for the purposes of illustration only, and not as a definition of the limits of the invention.
In the drawings, wherein similar reference characters denote similar elements throughout the several views;
FIG. 1 is a perspective view of one embodiment of the drying apparatus according to the invention;
FIG. 2 is an exploded perspective view of the drying apparatus of FIG. 1;
FIG. 3 is a cross-sectional view taken along section 3--3 of FIG. 1;
FIG. 4 is a perspective view of another embodiment of the drying apparatus of the invention;
FIG. 5 is a perspective view, slightly in cross section, of still a further embodiment of an industrial application of the apparatus according to the invention;
FIG. 6 is an electrical block diagram, partly in schematic form of an electrical operating circuit of one form of the dryer;
FIG. 7 is a cross-sectional view of still a further embodiment of the dryer utilizing adapter for hair drying;
FIGS. 8 and 9 disclose in cross-sectional view an attachment to the dryer for facial drying;
FIG. 10 is an electrical schematic diagram of the operating circuit for the apparatus of FIG. 5;
FIG. 11 is a further electrical block diagram partly in schematic of another operating circuit of the invention;
FIGS. 12 and 13 disclose still a further embodiment of the invention showing the blower assembly utilized for cooling the blower motor;
FIG. 14 is an electrical schematic diagram for reducing the power applied to the blower to one-half its capacity.
Referring to FIGS. 1-3, there is shown one embodiment of the dryer according to the invention, constructed in a housing 10 for mounting either against or into a vertical wall 11, and includes a rectangularly shaped opening 12 for receiving articles to be dried. In the exploded view of FIG. 2, the blower assembly 13 includes a tangential blower 16 which is pivotably connected to the shaft of motor 14. Blower housing 13 includes mounting brackets 15 and 17 for securing the blower apparatus to the housing of the dryer. An electrical line 66 connects motor 14 to a thermistor switch 66, and through line 19 to circuitry 67, which is discussed in more detail with reference to FIG. 6. A three-prong electrical connector 18 is secured to the circuitry for sliding connection to a corresponding socket 32 which is secured within housing 29.
Disposed below tangential blower 16 and the motor assembly, is a metal screen 22 which is retained between insulated retaining brackets 20 and 23 by means of screws which are inserted through corresponding screw holes 21 and 24, and secured to corresponding screw holes 68 which are mounted in the top portion of chamber 12 contained within wall 26, adjacent to its top opening 27. The screen and bracket assembly can then be secured over top opening 27 of chamber 12. Walls 26 in chamber 12 are formed against plate 25 which serves as the front cover of apparatus 10. A lock 28 is also provided near the top center of cover 25 for engagement with a catch 30 secured within the top of chamber 29. Mounting holes 31 are provided against the backwall of chamber 29 for accommodating mounting screws 38 to secure apparatus 10 within an opening in wall 11. If it is not possible to recess the drying apparatus within wall 11, then chamber 29 may be secured directly against wall 11 by means of mounting screws 38 through holes 31, and a decorative bezel 33, having spacers 35 and 34, may be slid over to contain and surround chamber 39, so as to permit the drying apparatus to be cantilevered out from wall surface 11. Between the input and output of the blower, is disposed a blower vane 8 which separates the path of the air between the input to the blower and its output, as shown, in detail in FIGS. 3, 7, 8 and 9. Heating element 9 may be connected either in front of the intake or exhaust of blower 14, or in both positions, in order to heat the recycling air in chamber 12. Heating element 9 is designed for fast replacement, and can be easily interchanged for maintenance. Because of the large surface area of the heater element, and its elongated, thin wall construction, the air coming from the blower travels around both sides of the heating element in a laminar flow pattern causing it to operate in the nonvisible thermal range thereby assuring its long operating life. A sterilizing lamp 5, as shown in FIG. 2, may be connected to the circuitry so as to illuminate the user's hands during the operation of the blower. An AC electrical line 37 is shown connected to socket 32. Plug 18 and its corresponding electrical socket 32 permit the dryer assembly to be quickly disconnected from its wall mounted chamber 29 by merely unfastening catch 28 and pulling outward on front panel 25. This permits the dryer assembly, normally mounted within chamber 29, to be quickly replaced with a reserve unit, while the original unit is serviced or repaired.
Referring to FIG. 4, there is another embodiment of the dryer according to the invention for use as a food warmer, wherein a sliding door 70 is provided slidably retained in tracks on vertical brackets 72, secured along the front vertical edges of dryer 10. A handle 70 is provided for raising and lowering door 71, and stops 73 are provided at the bottom of brackets to prevent disengagement of the door. Door 71 may be constructed from a transparent material so that the user of the apparatus may observe food articles placed within chamber 12 while they are being warmed when door 71 is closed across the opening of the chamber.
A microswitch 7 is mounted along the front face of housing 10, adjacent to the bottom of chamber 12, so that its actuating plunger 6 is directed upward for contact with the bottom edge of sliding door 70. Microswitch 7 is connected as shown in FIG. 14 to operate motor 14 and heater 9. When door 70 is closed over the front opening of chamber 12, microswitch 7 is actuated so that motor 14 and heater 9 operate at one-half power. Switch 7 is normally closed so that when door 70 actuates microswitch 7, switch 7 opens as shown in FIG. 14, to permit a resistive element 5, which may consist of a resistor or SCR circuit, to reduce the power applied to motor 14 and heater 9 to one-half its capacity.
Referring to FIG. 5, there is shown an industrial application of the invention having an elongated housing 100 with two side-by-side chamber openings 83 and 84. Disposed above the chambers is a U-shaped motor housing 85, which contains a motor 80 with two shaft outputs connected to tangential blower 81, disposed over chamber 83 and tangential blower 82, disposed over chamber 84. Blowers 81 and 82 are pivotably secured at their ends by end blocks 86 and 87 mounted against the walls of housing 100. Mounted along the bottom entrance rim of chamber 83 is a switch member 88 which consists of an elongated trip bar which is slidably disposed within the chamber for a small downward movement when it is contacted by the hands or arms of the user. Bar 88 is semicircular in cross section, and includes pins 89 which are secured in its bottom flat face, and are slidably disposed within corresponding holes contained within chamber 83. Mounted on each end of bar 88 are retaining brackets 90, which are secured against the sidewalls of chamber 83. Each of brackets 90 include an enlarged hole 91 for receiving a guide pin 92 which is secured to each end of bar 88. Brackets 90 also include axis pins 93, displaced away from guide pins 92 which are pivotably retained within bracket 90. Disposed under the flat portion of bar 88 and secured within housing 100 is a switch 94 having its spring-loaded plunger 95 urged against the bottom of the bar, so that the flat bottom surface of the bar is maintained slightly above the floor of chamber 83. Bar 88 is preferably constructed from a magnetic material such as iron. An electromagnet 129 is shown disposed under bar 88, and will momentarily hold bar 88 in a depressed position for a short time.
Referring to FIG. 10, there is shown an electrical schematic diagram of the operating circuit for the apparatus of FIG. 5. In its normal condition when the dryer is not in use, capacitor 125 is charged from the powerline connected through switch 94 to diode 126. Resistor 127 serves to prevent an excess of current from flowing through diode 126 when switch 94 returns to the normal operating position. When strip bar 88 is depressed, plunger 95 of switch 94 connects AC power to heater 209, blower motor 80, SCR or TRIAC 128, and to electromagnet 129. Electromagnet 129, which is disposed underneath metal bar 88, will be energized since SCR or TRIAC 128 will be conducting for a period of several seconds, due to the residual charge on capacitor 125 which flows through resistors 130 and 131, to the gate of SCR or TRIAC 128. Electromagnet 129 thus holds bar 88 down even though the user may inadvertently release pressure on it, during the delay time period of several seconds, so that the dryer remains operating.
Several seconds after bar 88 is actuated, capacitor 125 will discharge so that there will be sufficient current flowing into the gate terminal of SCR or TRIAC 128, so that it will cease to conduct. Electromagnet 129 will release bar 88, and switch 94 will revert to its normal position.
Capacitor 125 begins to discharge as soon as bar 88 is depressed. If the bar is kept depressed for a period of time longer than the time-delay period, SCR or TRIAC 128 will no longer continue to conduct, and the blower and heater will shut off as soon as the bar is released. Resistor 131 is a variable resistor so as to permit adjustment of the time-delay circuit connected to the gate of SCR or TRIAC 128, so that the sustained operation of the blower and heater can be adjusted to any desired predetermined time interval. The circuitry of FIG. 10 is disposed in the internal compartment (not shown) between chambers 83 and 84 below motor 80 of the apparatus of FIG. 5.
FIG. 7 is a cross-sectional view of another embodiment of the blower wherein the height of the dryer housing is increased slightly to provide a storage chamber immediately below chamber 12 in order to accommodate an adapter box 61 and its associated accessories for hair drying. Box 61 consists of a rectangularly shaped chamber having a flexible hose 60 connected on one side, and a handle 62 connected to the other side to permit the box to be easily removed from its lower compartments. Adapter box 61 is then fitted into chamber 12 so that its open top portion closes off the heated exhaust air of the blower. The height of box 61 is constructed slightly smaller than chamber 12 to permit intake air to enter the front of chamber 12, as shown by the arrows, and into the input of the tangential blower. The heated exhaust air can then be forced through flexible tube 60 to be dispersed through a head cap 99 worn by the user for hair drying purposes.
In FIGS. 8 and 9, another embodiment of the invention is disclosed for use as a facial dryer. In this embodiment a pushbutton 39 is provided on the front of the panel disposed immediately below a pivotable door 40 closing off an opening 41 disposed in front portion 25 of the apparatus. Button 39 is spring loaded by means of a spring 42, and is connected to a pushrod 44 having a plurality of spaced-apart pivotable gates 45 connected at intervals on the rod. When pushbutton 39 is not depressed as shown in FIG. 8, gates 45 remain open to permit the heated air to flow downward into chamber 12. However, when button 39 is depressed as shown in FIG. 9, cover door 40 will open, while gate 45 will close across the path of the exhaust air so that the exhaust air will exit from front panel 25 through opening 41.
Referring to FIG. 6, there is shown a schematic diagram of the electrical circuitry for operating a proximity control-type drying apparatus. A proximity control circuit 105, as is well known in the art, has its input connected to screen 22 which senses changes in the capacitive reactance between screen 22 and housing 10, inside of chamber 12. When the user places his hands in chamber 12, between screen 22 and housing 10, control circuit 105 will energize relay coil 106, connected to its output, so as to close contact 107 to provide AC power through circuit breaker 108 and motor 109. Heater 9 and circuit breaker 110 are also connected to the AC line by the closing of switch contact 107.
The resettable thermal circuit breaker 108 is connected within motor housing 14 and senses the temperature of the blower motor so that if a predetermined temperature is exceeded, the circuit to the motor will be interrupted by circuit breaker 108 requiring the breaker to be manually reset before the motor may be operated. The resettable thermal circuit breaker 110 is connected in series with heater 9 for sensing the temperature of the heater so that if the temperature becomes excessive, circuit breaker 110 will interrupt the current going to the line requiring manual resetting in order to reestablish the current path to the heater.
In FIG. 11, there is shown a heat proportional circuit 67 connected to one terminal of heater element 9 consisting of the parallel combination of silicon control rectifier (SCR) 112, diode 113 in reverse bias, and the series combination of diode 116, resistor 115, and thermistor 66. Thermistor 66 is disposed adjacent to the blower so as to sense the temperature of the air. The output of thermistor 66 is connected to the gate of SCR 112 so that when the air temperature increases within chamber 12 as the user's hands are being dried, SCR 112 will cut back on the amount of current being supplied to heater element 9. Thermistor 66 will thus control the temperature of the recycling air by limiting the current applied to heater element 9.
Referring to FIGS. 12 and 13, there is shown blower motor 14 having at one end a plurality of air vent openings 144 which are directed toward correspondingly placed air vent openings 143 disposed along the sidewall of chamber 29. Connected to the internal portion of the sidewall of chamber 29 is a cowl 141 which forms a partially sealed chamber between the end of the motor and the side panel of chamber 29. On the front end of motor 14 within blower housing 36 is disposed a second cowl 140 which surrounds tangential blower 16 to complete a linear air path between the blower and the motor so that cool air can be pulled through openings 143 and 144 and through the motor housing, by means of the movement of tangential blower 16. The heating effect of the motor is therefore utilized by the fan together with the heat from heating elements 9 for drying the user's hands within chamber 12.
The air exiting from the blower of all of the embodiments is forced downward toward the front portion of the drying chamber and recirculates near the bottom of the chamber so that substantially all of the air reenters the blower toward the back of the chamber, at the blower input.
While only a few embodiments of the present invention have been shown and described, it will be understood that many changes and modifications may be made thereunto without departing from the spirit and scope of the invention.
More specifically, this invention relates to an electric hand dryer, which may also be easily adapted for use as a hair dryer, face dryer, food warmer, room heater, clothes dryer, and the like.
Conventional drying devices such as hand dryers generally consist of an air blower which directs a stream of air through electric heating elements before the air is dispersed from its outlet. The output nozzle directs the warm, dry air onto the hands of the user for a predetermined drying cycle. When the user's hands are placed in the path of the moving air emitted from the nozzle, only one side of the user's hands are dried at a time, and the user must rotate his hands in front of the dryer so that they will be completely dried during the running cycle of the apparatus. Moreover, the airstream tends to blow the water from the user's hands over his clothing. The water also drips onto the floor in front of the dryer while the hands are being dried. The airstream directed from the front of the conventional dryer also heats up the room so that after repeated usage, the room containing the conventional dryer becomes excessively heated. The conventional hand dryers are generally constructed for a single purpose only and are not readily adaptable for use as a hair and face dryer, food warmer, room heater and the like.
Accordingly, the present invention provides an improved electric drying apparatus which provides a partially enclosed chamber within its housing so that the user's hands can be inserted into this chamber during the drying cycle. Warm, dry air, which is directed in a circular flow path within the chamber of the apparatus, contacts the user's hands on all sides so that it is not necessary for the user to rotate his hands within the chamber of the apparatus. Moreover, the circular movement of the warm dry air within the chamber of the apparatus permits a major portion of the air to be recirculated through the blower of the dryer, and reheated, so that only a small portion of the dry air escapes from the chamber opening at the front of the apparatus. By recirculating the warm, dry air of the blower, it is possible to provide a hand dryer which is more efficient in operation, and which requires less electrical power and uses smaller components than conventional hand dryers. Moreover, since the warm, dry air is directed tin a circular flow, the air completely surrounds the user's hands so that they are dried in less time than ordinarily required by conventional hand dryers. The dryer also does not excessively heat the surrounding room or permit water to drip on the floor or the user's clothes. In other embodiments of the invention, modifications are provided which permit the drying apparatus to be utilized as a food warmer, hair dryer, face dryer, clothes dryer, room heater and the like.
It is therefore an object according to the present invention to provide a drying apparatus which is capable for use as an improved hand dryer as well as a variety of other drying applications.
It is another object according to the present invention to provide a drying apparatus when recycles a major portion of its output to perform a more efficient drying cycle.
It is still a further object according to the present invention to provide an electric hand dryer which is simple in design, easy to construct and reliable in operation.
Other objects and features of the present invention will become apparent from the following detailed description considered in connection with the accompanying drawings which disclose several embodiments of the present invention. It is to be understood, however, that the drawings are designed for the purposes of illustration only, and not as a definition of the limits of the invention.
In the drawings, wherein similar reference characters denote similar elements throughout the several views;
FIG. 1 is a perspective view of one embodiment of the drying apparatus according to the invention;
FIG. 2 is an exploded perspective view of the drying apparatus of FIG. 1;
FIG. 3 is a cross-sectional view taken along section 3--3 of FIG. 1;
FIG. 4 is a perspective view of another embodiment of the drying apparatus of the invention;
FIG. 5 is a perspective view, slightly in cross section, of still a further embodiment of an industrial application of the apparatus according to the invention;
FIG. 6 is an electrical block diagram, partly in schematic form of an electrical operating circuit of one form of the dryer;
FIG. 7 is a cross-sectional view of still a further embodiment of the dryer utilizing adapter for hair drying;
FIGS. 8 and 9 disclose in cross-sectional view an attachment to the dryer for facial drying;
FIG. 10 is an electrical schematic diagram of the operating circuit for the apparatus of FIG. 5;
FIG. 11 is a further electrical block diagram partly in schematic of another operating circuit of the invention;
FIGS. 12 and 13 disclose still a further embodiment of the invention showing the blower assembly utilized for cooling the blower motor;
FIG. 14 is an electrical schematic diagram for reducing the power applied to the blower to one-half its capacity.
Referring to FIGS. 1-3, there is shown one embodiment of the dryer according to the invention, constructed in a housing 10 for mounting either against or into a vertical wall 11, and includes a rectangularly shaped opening 12 for receiving articles to be dried. In the exploded view of FIG. 2, the blower assembly 13 includes a tangential blower 16 which is pivotably connected to the shaft of motor 14. Blower housing 13 includes mounting brackets 15 and 17 for securing the blower apparatus to the housing of the dryer. An electrical line 66 connects motor 14 to a thermistor switch 66, and through line 19 to circuitry 67, which is discussed in more detail with reference to FIG. 6. A three-prong electrical connector 18 is secured to the circuitry for sliding connection to a corresponding socket 32 which is secured within housing 29.
Disposed below tangential blower 16 and the motor assembly, is a metal screen 22 which is retained between insulated retaining brackets 20 and 23 by means of screws which are inserted through corresponding screw holes 21 and 24, and secured to corresponding screw holes 68 which are mounted in the top portion of chamber 12 contained within wall 26, adjacent to its top opening 27. The screen and bracket assembly can then be secured over top opening 27 of chamber 12. Walls 26 in chamber 12 are formed against plate 25 which serves as the front cover of apparatus 10. A lock 28 is also provided near the top center of cover 25 for engagement with a catch 30 secured within the top of chamber 29. Mounting holes 31 are provided against the backwall of chamber 29 for accommodating mounting screws 38 to secure apparatus 10 within an opening in wall 11. If it is not possible to recess the drying apparatus within wall 11, then chamber 29 may be secured directly against wall 11 by means of mounting screws 38 through holes 31, and a decorative bezel 33, having spacers 35 and 34, may be slid over to contain and surround chamber 39, so as to permit the drying apparatus to be cantilevered out from wall surface 11. Between the input and output of the blower, is disposed a blower vane 8 which separates the path of the air between the input to the blower and its output, as shown, in detail in FIGS. 3, 7, 8 and 9. Heating element 9 may be connected either in front of the intake or exhaust of blower 14, or in both positions, in order to heat the recycling air in chamber 12. Heating element 9 is designed for fast replacement, and can be easily interchanged for maintenance. Because of the large surface area of the heater element, and its elongated, thin wall construction, the air coming from the blower travels around both sides of the heating element in a laminar flow pattern causing it to operate in the nonvisible thermal range thereby assuring its long operating life. A sterilizing lamp 5, as shown in FIG. 2, may be connected to the circuitry so as to illuminate the user's hands during the operation of the blower. An AC electrical line 37 is shown connected to socket 32. Plug 18 and its corresponding electrical socket 32 permit the dryer assembly to be quickly disconnected from its wall mounted chamber 29 by merely unfastening catch 28 and pulling outward on front panel 25. This permits the dryer assembly, normally mounted within chamber 29, to be quickly replaced with a reserve unit, while the original unit is serviced or repaired.
Referring to FIG. 4, there is another embodiment of the dryer according to the invention for use as a food warmer, wherein a sliding door 70 is provided slidably retained in tracks on vertical brackets 72, secured along the front vertical edges of dryer 10. A handle 70 is provided for raising and lowering door 71, and stops 73 are provided at the bottom of brackets to prevent disengagement of the door. Door 71 may be constructed from a transparent material so that the user of the apparatus may observe food articles placed within chamber 12 while they are being warmed when door 71 is closed across the opening of the chamber.
A microswitch 7 is mounted along the front face of housing 10, adjacent to the bottom of chamber 12, so that its actuating plunger 6 is directed upward for contact with the bottom edge of sliding door 70. Microswitch 7 is connected as shown in FIG. 14 to operate motor 14 and heater 9. When door 70 is closed over the front opening of chamber 12, microswitch 7 is actuated so that motor 14 and heater 9 operate at one-half power. Switch 7 is normally closed so that when door 70 actuates microswitch 7, switch 7 opens as shown in FIG. 14, to permit a resistive element 5, which may consist of a resistor or SCR circuit, to reduce the power applied to motor 14 and heater 9 to one-half its capacity.
Referring to FIG. 5, there is shown an industrial application of the invention having an elongated housing 100 with two side-by-side chamber openings 83 and 84. Disposed above the chambers is a U-shaped motor housing 85, which contains a motor 80 with two shaft outputs connected to tangential blower 81, disposed over chamber 83 and tangential blower 82, disposed over chamber 84. Blowers 81 and 82 are pivotably secured at their ends by end blocks 86 and 87 mounted against the walls of housing 100. Mounted along the bottom entrance rim of chamber 83 is a switch member 88 which consists of an elongated trip bar which is slidably disposed within the chamber for a small downward movement when it is contacted by the hands or arms of the user. Bar 88 is semicircular in cross section, and includes pins 89 which are secured in its bottom flat face, and are slidably disposed within corresponding holes contained within chamber 83. Mounted on each end of bar 88 are retaining brackets 90, which are secured against the sidewalls of chamber 83. Each of brackets 90 include an enlarged hole 91 for receiving a guide pin 92 which is secured to each end of bar 88. Brackets 90 also include axis pins 93, displaced away from guide pins 92 which are pivotably retained within bracket 90. Disposed under the flat portion of bar 88 and secured within housing 100 is a switch 94 having its spring-loaded plunger 95 urged against the bottom of the bar, so that the flat bottom surface of the bar is maintained slightly above the floor of chamber 83. Bar 88 is preferably constructed from a magnetic material such as iron. An electromagnet 129 is shown disposed under bar 88, and will momentarily hold bar 88 in a depressed position for a short time.
Referring to FIG. 10, there is shown an electrical schematic diagram of the operating circuit for the apparatus of FIG. 5. In its normal condition when the dryer is not in use, capacitor 125 is charged from the powerline connected through switch 94 to diode 126. Resistor 127 serves to prevent an excess of current from flowing through diode 126 when switch 94 returns to the normal operating position. When strip bar 88 is depressed, plunger 95 of switch 94 connects AC power to heater 209, blower motor 80, SCR or TRIAC 128, and to electromagnet 129. Electromagnet 129, which is disposed underneath metal bar 88, will be energized since SCR or TRIAC 128 will be conducting for a period of several seconds, due to the residual charge on capacitor 125 which flows through resistors 130 and 131, to the gate of SCR or TRIAC 128. Electromagnet 129 thus holds bar 88 down even though the user may inadvertently release pressure on it, during the delay time period of several seconds, so that the dryer remains operating.
Several seconds after bar 88 is actuated, capacitor 125 will discharge so that there will be sufficient current flowing into the gate terminal of SCR or TRIAC 128, so that it will cease to conduct. Electromagnet 129 will release bar 88, and switch 94 will revert to its normal position.
Capacitor 125 begins to discharge as soon as bar 88 is depressed. If the bar is kept depressed for a period of time longer than the time-delay period, SCR or TRIAC 128 will no longer continue to conduct, and the blower and heater will shut off as soon as the bar is released. Resistor 131 is a variable resistor so as to permit adjustment of the time-delay circuit connected to the gate of SCR or TRIAC 128, so that the sustained operation of the blower and heater can be adjusted to any desired predetermined time interval. The circuitry of FIG. 10 is disposed in the internal compartment (not shown) between chambers 83 and 84 below motor 80 of the apparatus of FIG. 5.
FIG. 7 is a cross-sectional view of another embodiment of the blower wherein the height of the dryer housing is increased slightly to provide a storage chamber immediately below chamber 12 in order to accommodate an adapter box 61 and its associated accessories for hair drying. Box 61 consists of a rectangularly shaped chamber having a flexible hose 60 connected on one side, and a handle 62 connected to the other side to permit the box to be easily removed from its lower compartments. Adapter box 61 is then fitted into chamber 12 so that its open top portion closes off the heated exhaust air of the blower. The height of box 61 is constructed slightly smaller than chamber 12 to permit intake air to enter the front of chamber 12, as shown by the arrows, and into the input of the tangential blower. The heated exhaust air can then be forced through flexible tube 60 to be dispersed through a head cap 99 worn by the user for hair drying purposes.
In FIGS. 8 and 9, another embodiment of the invention is disclosed for use as a facial dryer. In this embodiment a pushbutton 39 is provided on the front of the panel disposed immediately below a pivotable door 40 closing off an opening 41 disposed in front portion 25 of the apparatus. Button 39 is spring loaded by means of a spring 42, and is connected to a pushrod 44 having a plurality of spaced-apart pivotable gates 45 connected at intervals on the rod. When pushbutton 39 is not depressed as shown in FIG. 8, gates 45 remain open to permit the heated air to flow downward into chamber 12. However, when button 39 is depressed as shown in FIG. 9, cover door 40 will open, while gate 45 will close across the path of the exhaust air so that the exhaust air will exit from front panel 25 through opening 41.
Referring to FIG. 6, there is shown a schematic diagram of the electrical circuitry for operating a proximity control-type drying apparatus. A proximity control circuit 105, as is well known in the art, has its input connected to screen 22 which senses changes in the capacitive reactance between screen 22 and housing 10, inside of chamber 12. When the user places his hands in chamber 12, between screen 22 and housing 10, control circuit 105 will energize relay coil 106, connected to its output, so as to close contact 107 to provide AC power through circuit breaker 108 and motor 109. Heater 9 and circuit breaker 110 are also connected to the AC line by the closing of switch contact 107.
The resettable thermal circuit breaker 108 is connected within motor housing 14 and senses the temperature of the blower motor so that if a predetermined temperature is exceeded, the circuit to the motor will be interrupted by circuit breaker 108 requiring the breaker to be manually reset before the motor may be operated. The resettable thermal circuit breaker 110 is connected in series with heater 9 for sensing the temperature of the heater so that if the temperature becomes excessive, circuit breaker 110 will interrupt the current going to the line requiring manual resetting in order to reestablish the current path to the heater.
In FIG. 11, there is shown a heat proportional circuit 67 connected to one terminal of heater element 9 consisting of the parallel combination of silicon control rectifier (SCR) 112, diode 113 in reverse bias, and the series combination of diode 116, resistor 115, and thermistor 66. Thermistor 66 is disposed adjacent to the blower so as to sense the temperature of the air. The output of thermistor 66 is connected to the gate of SCR 112 so that when the air temperature increases within chamber 12 as the user's hands are being dried, SCR 112 will cut back on the amount of current being supplied to heater element 9. Thermistor 66 will thus control the temperature of the recycling air by limiting the current applied to heater element 9.
Referring to FIGS. 12 and 13, there is shown blower motor 14 having at one end a plurality of air vent openings 144 which are directed toward correspondingly placed air vent openings 143 disposed along the sidewall of chamber 29. Connected to the internal portion of the sidewall of chamber 29 is a cowl 141 which forms a partially sealed chamber between the end of the motor and the side panel of chamber 29. On the front end of motor 14 within blower housing 36 is disposed a second cowl 140 which surrounds tangential blower 16 to complete a linear air path between the blower and the motor so that cool air can be pulled through openings 143 and 144 and through the motor housing, by means of the movement of tangential blower 16. The heating effect of the motor is therefore utilized by the fan together with the heat from heating elements 9 for drying the user's hands within chamber 12.
The air exiting from the blower of all of the embodiments is forced downward toward the front portion of the drying chamber and recirculates near the bottom of the chamber so that substantially all of the air reenters the blower toward the back of the chamber, at the blower input.
While only a few embodiments of the present invention have been shown and described, it will be understood that many changes and modifications may be made thereunto without departing from the spirit and scope of the invention.