WO1997030616A1

WO1997030616A1 - Device for automatically controlling the steam valve in electric pressure cookers

Info

Publication number: WO1997030616A1
Application number: PCT/KR1996/000069
Authority: WO
Inventors: Joong Kwang Suk
Original assignee: Ban Sung Co., Ltd.
Priority date: 1996-02-24
Filing date: 1996-05-07
Publication date: 1997-08-28
Also published as: KR970050871U

Abstract

A device for automatically controlling the steam valve in electric pressure cookers is disclosed. In the above device, a worm gear gears into a worm fixed to the output shaft of a drive motor. The motor is operated under the control of a microcomputer. The top and bottom sides of the worm gear have top and bottom cams. Each cam is gradually thickened from one end to the other end thereof. The top cam is brought into contact with the protrusion of a flange formed on the upper portion of the valve pipe, thus selectively pushing up the flange along with the valve pipe. The valve packing of the valve pipe is pushed up to open the steam port of the valve body, thus exhausting the pressurized steam from the cooker through the steam valve. Meanwhile, the bottom cam of the worm gear comes into contact with a sensing switch and selectively turns on the sensing switch.

Description

DEVICE FOR AUTOMATICALLY CONTROLLING THE STEAM VALVE IN ELECTRIC PRESSURE COOKERS

Technical Field

The present invention relates in general to a device for automatically opening or closing the steam valve in electric pressure cookers and, more particularly, to a structural improvement in such a device for easily and safely opening or closing the steam valve and making the cookers convenient to users.

Background Art

After cooking rice with an electric pressure cooker, the pressurized steam must be exhausted from the cooker through a steam valve prior to opening the lid of the cooker. In typical electric pressure cookers, the pressurized steam may be exhausted from the cooker by either manually tilting an openable weight movably seated on the top of a steam valve or electromagnetically opening the valve using a solenoid valve. However, the use of the openable weight causes a safety problem in that the user may burn one's fingers on the hot weight when manually tilting the weight. On the other hand, the solenoid valve must be continuously applied with electricity to pull the valve weight while opening the steam valve. The solenoid thus wastes electricity and sometimes applies overload to the steam valve while opening the valve. The use of the solenoid valve also may cause a short circuit due to overcurrent, thereby failing to achieve operational stability and being inconvenient to the user. Disclosure of the Invention

It is, therefore, an object of the present invention to provide a device for automatically controlling the steam valve in electric pressure cookers in which the above problems can be overcome and which automatically moves the valve packing of a valve pipe relative to the steam port of a valve body and thereby automatically opens or closes the steam port, thus easily and safely opening or closing the steam valve and making the cookers convenient to the user.

In order to accomplish the above object, the device for automatically controlling the steam valve in electric pressure cookers according to the preferred embodiment of the present invention comprises a valve body and longitudinal valve pipe. The valve body is mounted to the lid of the cooker and has a steam port opening to the interior of the cooker. The valve pipe has a valve packing on its bottom end and is ovably seated on the valve body to normally close the steam port of the valve body by the valve packing. The device further comprises a flange mounted to the upper portion of the valve pipe. The flange has a protrusion on the bottom side thereof. A worm gear is rotatably mounted to a bracket plate provided under the flange. The top and bottom sides of the worm gear have top and bottom arcuate cams which are diametrically oppositely positioned along the peripheral edges of the top and bottom sides of the worm gear. Each cam is gradually thickened from one end to the other end thereof, thus having a tapered surface. The top cam is brought into contact with the protrusion of the flange to selectively push up the valve body and thereby opening the steam port in accordance with a rotating motion of the worm gear. The bottom cam is brought into contact with a sensing switch in order to turn on or off the sensing switch. A microcomputer is electrically connected to the sensing switch and checks a positional state of the valve pipe using a sensing signal output from the sensing switch. A drive motor is electrically connected to the microcomputer through a motor drive integrated circuit and operated under the control of the microcomputer. A worm is fixed to an output shaft of the drive motor and gears into the worm gear, thereby rotating the worm gear with the rotating force of the drive motor.

Brief Description of the Drawings

The above and other objects, features and other advantages of the present invention will be more clearly understood from the following detailed description taken in conjunction with the accompanying drawings, in which:

Fig. 1 is an exploded perspective view showing the construction of a steam valve controlling device in accordance with a preferred embodiment of the present invention;

Fig. 2 is a sectional view of a cooker's top lid with the steam valve controlling device according to the present invention;

Fig. 3 is a sectional view of the cooker's top lid of Fig. 2, showing the operation of the valve controlling device of the present invention;

Fig. 4 is a plan view of the valve controlling device looked at from the line A-A of Fig. 2; and

Fig. 5 is a diagram showing the control circuit with a microcomputer, switches and motor in the valve controlling device of the present invention. Best Mode for Carrying Out the Invention

Fig. 1 shows the construction of a device for automatically controlling the steam valve in electric pressure cookers in accordance with a preferred embodiment of the present invention. Fig. 2 shows the cooker's lid with the above steam valve controlling device.

As shown in the drawings, the steam valve 1 includes a valve body 4 which is interposed between the bottom εide 2' of the cooker's top lid 2 and the pressure lid 2". The above valve body 4 is outer-threaded and tightened by a cap nut 5 outside the pressure lid 2". The bottom center of the above valve body 4 is vertically perforated to form a steam port 3. The interior of the valve body 4 communicates with the interior of the cooker by the steam port 3. A longitudinal valve pipe 6 is vertically seated on the valve body 4 in a way such that the top end of the valve pipe 6 is exposed outside the top surface of the top lid 2. The bottom end of the above valve pipe 6 is provided with a valve packing 7. The packing 7 is normally seated on the steam port 3 of the valve body 4 and selectively opens the steam port 3. A stop ring 8 is fixedly fitted over the lower portion of the valve pipe 6 and stops the lower end of a compression coil spring 9. The top end of the above spring 9 is stopped by a bracket plate 15 which will be described later herein. An inner- threaded valve cap 11, which is provided with a steam exhaust port 10, is threaded to the outer-threaded upper portion of the above valve pipe 6. The steam exhaust port 10 of the valve cap 11 communicates with the steam passage 6* of the valve pipe 6, thus vertically exhausting the pressurized steam from the cooker. In the above steam valve 1, a top flange 12 is formed on the upper portion of the above valve pipe 6. The bottom side of the above flange 12 is provided with a contact protrusion 13. Mounted to the top of the valve body 4 by a screw above the bottom side 2' of the top lid 2 is the bracket plate 15. A worm gear 18 is rotatably mounted to the top of the above bracket plate 15. The above worm gear 18 gears into a worm 17. The worm 17 is fixed to the output shaft 16 of a drive motor M. The top and bottom sides of the above worm gear 18 are provided with top and bottom cams 19 and 19' having an arcuate configuration. As best seen in Fig. 1, the cams 19 and 19' are positioned along the peripheral edges of the top and bottom sides of the worm gear 18, respectively, in a way such that they are placed diametrically oppositely. Each cam 19 or 19' is gradually thickened from one end to the other end thereof, thus having a tapered surface. The top cam 19 comes into contact with the protrusion 13 of the top flange 12, while the bottom cam 19' is brought into contact with a sensing switch SW_j in order to turn on or off the switch S ₁. The above drive motor M is connected to a microcomputer C through a motor drive integrated circuit (IC) I as shown in Fig. 5. The above microcomputer C is also connected to the sensing switch S _j, start switch Sf^, withdrawal switch SW₃ and a display window D. The display window D is provided on the control panel of a cooker.

Fig. 4 is a plan view of the valve controlling device looked from the line A-A of Fig. 2.

In the drawings, the reference character B denotes a buzzer for informing the user of the operational state of the cooker.

In the operation of the cooker with the above steam valve controlling device, the valve packing 7 of the valve pipe 6 tightly closes the steam port 3 of the valve body 4 at the initial stage of cooking. As the pressure inside the cooker is gradually increased, the pressurized steam is applied to the packing 7 thus pushing the packing 7 upward. The valve pipe 6 in the above state is thus pushed upward while compressing the coil spring 9. The steam port 3 of the valve body 4 iε thus opened. The pressurized steam iε introduced into the valve body 4 through the εteam port 3 and in turn flowε upward through the steam passage 6' inside the valve pipe 6. Thereafter, the pressurized steam iε exhausted into the atmoεphere through the steam exhaust port 10 of the valve cap 11. When the pressure inside the cooker is reduced as the pressurized steam is exhausted to the atmosphere, the valve pipe 6 is pushed down by the restoring force of the compreεsion coil spring 9, thus causing the valve packing 7 to close the steam port 3 of the valve body 4.

When it is required to open the steam valve 1 and thereby to exhaust the pressurized steam from the cooker after cooking, the start switch SW_j is operated. The start switch SW₂ thus outputs a start signal to the microcomputer C. Upon receiving the start signal, the microcomputer C selectively outputs a motor control εignal to the motor drive IC in accordance with the sensing signal output from the sensing switch SW_j, thus starting the motor M. The rotating force of the motor M in the above state is transmitted to the worm gear 18 through the worm 17, thereby rotating the worm gear 18 with the top and bottom cams 19 and 19*. The top cam 19 in the above state moves from the position in Fig. 2 to the position in Fig. 3, thus vertically pushing up the protrusion 13 of the top flange 12. The valve pipe 6 is thus pushed upward while compressing the compression coil spring 9, while the valve packing 7 opens the steam port 3 of the valve body 4 to exhaust the pressurized steam from the cooker through the steam valve 1. When the protrusions 13 of the flange 12 come into contact with the thinnest portion of the top cam 19 as the worm gear 188 further rotates, the valve pipe 4 is pushed down by the restoring force of the coil 9 thus causing the valve packing 7 to close the steam port 3 of the valve body 4. On the other hand, when the worm gear 18 rotates by the rotating force of the motor M, the bottom cam 19' is brought into contact with the sensing switch SW_j thereby turning on the switch SW, . The operating state of the sensing switch SW₁ in the above state is easily checked by the microcomputer C. In this regard, the microcomputer C easily checks the operating state of the steam valve 1, thus allowing the steam valve 1 to be easily operated outside the cooker.

Industrial Applicability

As described above, the present invention provides a device for automatically controlling the steam valve in electric pressure cookers. In the above device, a worm gear gears into a worm fixed to the output shaft of a drive motor. The above motor is operated under the control of a microcomputer which is connected to the motor through a motor drive integrated circuit. The top and bottom sides of the above worm gear are provided with top and bottom cams, respectively. The above cams are positioned on the peripheral edges of the top and bottom sides of the worm gear such that they are positioned diametrically oppositely. Each cam is gradually thickened from one end to the other end thereof. The top cam is brought into contact with a protrusion provided on the bottom side of a flange formed on the upper portion of the valve pipe, thus selectively pushing up the flange along with the valve pipe. The valve packing of the valve pipe in the above state is pushed up to open the steam port of the valve body, thus exhausting the pressurized steam from the cooker through the steam valve. Meanwhile, the bottom cam of the worm gear comes into contact with a sensing switch and selectively turns on the sensing switch in accordance with the rotating motion of the worm gear. The operating state of the sensing switch in the above state is checked by the microcomputer. The microcomputer thus checks the operating state of the steam valve and controls the motor. The steam valve controlling device of this invention thus easily and safely opens the steam valve after cooking to exhaust the pressurized steam from the cooker. The above device thus allows the cookers to be convenient to the user.

Although the preferred embodiments of the present invention have been discloεed for illustrative purposes, those skilled in the art will appreciate that various modifications, additions and substitutions are possible, without departing from the scope and spirit of the invention as disclosed in the accompanying claims.

Claims

Claim

1. A device for automatically controlling a steam valve in an electric pressure cooker, comprising a valve body mounted to a lid of εaid cooker and having a steam port communicating with the interior of said cooker; and a longitudinal valve pipe having a valve packing on its bottom end and movably seated on said valve body to normally close said steam port of the valve body by said valve packing, further comprising; a flange mounted to an upper portion of said valve pipe, said flange having a protrusion on a bottom side thereof; a worm gear rotatably mounted to a bracket plate provided under said flange, top and bottom sides of said worm gear having top and bottom arcuate cams which are diametrically oppoεitely poεitioned along peripheral edgeε of said top and bottom sides of the worm gear, each cam being gradually thickened from one end to the other end thereof thereby having a tapered surface, said top cam being brought into contact with said protrusion of the flange to selectively push up said valve body and thereby to open said steam port in accordance with a rotating motion of said worm gear, while said bottom cam being brought into contact with a sensing switch in order to turn on or off said sensing switch; a microcomputer electrically connected to said sensing switch and checking a positional state of said valve pipe using a sensing signal output from said sensing switch; a drive motor electrically connected to said microcomputer through a motor drive integrated circuit and operated under the control of said microcomputer; and a worm fixed to an output shaft of said drive motor and gearing into said worm gear, thereby rotating said worm gear with the rotating force of the drive motor.