FIELD OF INVENTION
The present invention relates to the field of electronics and instrumentation. More specifically the present invention is directed towards motor safety device for semi-automatic washing machine.
BACKGROUND OF THE INVENTION
Washing machine is the domestic electronic appliance which can be easily found in most of the houses for washing clothes without putting any manual efforts. The labor for rubbing and squeezing of clothes is eliminated with the automatic washing in the busy life schedule. There are generally two types of washing machines:
1. Semi-automatic washing machines
2. Fully automatic washing machines
Semi-automatic washing machines require manual intervention in the controls. These usually contain twin tubs. In one tub washing of clothes takes place and after the clothes are washed, they are then transferred to the second tub for spinning. However, single tub semi-automatic washing machines are also available. It is the most economical of all washing machines. Water consumption is less as it does not require a dedicated, continuous water supply like fully automated ones. Also, it consumes less power than fully automatic washing machines. Due to all the above mentioned characteristics, semi-automatic washing machines are generally found in most of the houses. However, the wash quality is said to be around 60% of fully automatic front load machines. The drawback of this machine is that it needs manual intervention. Also, water heating options are generally not available in semi-automatic washing machines.
In fully automatic washing machine once the dirty clothes, detergent and water are given as input and necessary instructions are given by means of the control switches, the machine takes control of washing. Dirty clothes are to be loaded and washed clothes are to be
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unloaded and there is no manual work in between. Fully automatic washing machines have sophisticated control and are costlier compared to semi-automatic washing machines.
Major parts of a basic washing machine (fully/semi-automatic washing machine) are:
1. Washing tub
2. Electric motor
3. Pump
4. Control panel and controlling mechanisms
5. Valves
6. Transmission mechanism
7. Sensors
8. Water lines
9. Agitator
10. Heater
11. Accessories
The general parts of the washing machine are shown in figure 1.
(Reference: www.rd.in)
Drive motor:
The electric motor is a single phase AC motor. Generally it is a universal motor or a capacitor type split phase motor and run squirrel cage induction motor. The same motor is used to drive the agitator during washing and to spin the inner tub during rinsing. This motor is normally protected from overload and overheating conditions by means of a bimetallic overload relay or a thermal switch and is located in such a way that leakage water does not enter into the
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motor normally. Still there are many ways due to which the motor is susceptible to damage or failure.
Causes of motor failure:
1. Leaving water in wash tub increases the load on the machine body and also the motor is housed below the tub so pulley may sometime lose alignment in long run. If there is any leak in machine body, it can cause short circuit.
2. Spin tub contains a buffer which uses araldite (a special type of water proof adhesive). If the water is stored in spin tub all the time, even the strong araldite adhesive can lose its power and opens some space for water leakage to the motor which is placed exactly below the spin tub. Any water leaked from spin tub reaches the spin motor to cause short circuit inside the motor.
3. If the machine is kept in drain mode for water outflow without letting down the outlet pipe for flow of water, it can make the water to fill into the spin tub which again leads to problem of short circuit.
Important accessories include metal frame with counterweight to keep the machine steady during operation, damping system to absorb vibration, agitator and wash tub driving mechanism, gearbox, overflow port to drain out water to prevent water overflow from the wash tub, couplings for motor and pump, control switches etc.
In future commercial appliances all the electrical parts, including the motor, may be placed at the top of the machine, i.e., directly under the cover and protected from water leaks. This increases the ease of repair as well as the life of the appliance. The present invention is directed towards a solution to prevent semi-automatic washing machine’s motor failure and short circuit.
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Problem in existing safety mechanisms for motors:
1. Existing safety mechanisms either have complex mechanisms or involve leakage prevention only which does not result in an efficient motor safety mechanism.
2. Existing safety mechanisms do not have provision of any alarm signal so that water leakage over the motor is being noticed by the user.
Prior art patents:
s no.
Patent application no.
Summary of invention
Comparison with present invention
1.
CN 203247423 U
The invention discloses a novel dewatering barrel motor cover switch of a semi-automatic washing machine. The motor cover comprises a magnet and a reed pipe. The magnet is installed at the lower end of a movable cover of a de-watering barrel of the washing machine and the reed pipe is installed on a washing machine shell at the lower end of the movable cover of the dewatering barrel of the washing machine. After the installation is finished, the magnetism of the magnet just acts on the reed pipe when the movable cover of the dewatering barrel of the washing machine is closed downward so that a contact in the reed pipe can be connected.
The invention comprises a safety mechanism for motor which consists of a piece of rubber with 3 strips which fits on a metal frame and this metal frame surrounds the motor. At the center of the rubber a bush is placed which is connected to motor through shaft. A circuit consists of two wires is placed in such a way that if there is water leakage from dryer seal then wires get automatically connected through water and dryer motor will stop working and generates an alarm signal which shows that there is a problem in dryer seal On the other hand, the compared invention is only a dewatering barrel motor cover switch.
2.
CN 203247422 U
The invention discloses a semi-automatic washing machine motor cover switching device based on a mercury switch. The motor cover switching device is composed of the mercury switch, an outer shell and wires. The mercury switch is installed inside the outer shell, the number of the wires is two, the wires are connected with two terminals of the mercury switch respectively and the outer shell is installed at
The invention comprises a safety mechanism for motor which consists of a piece of rubber with 3 strips which fits on a metal frame and this metal frame surrounds the motor. At the center of the rubber a bush is placed which is connected to motor through shaft. A circuit consists of two wires is placed in such a way that if there is water leakage from dryer seal then wires get automatically
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the lower end of a semi-automatic washing machine water removing barrel movable cover.
connected through water and dryer motor will stop working and generates an alarm signal which shows that there is a problem in dryer seal . On the other hand, the compared invention is a complex motor cover switching device.
3.
US 1323850 A
The invention discloses a safety connection for electric motor in washing machine. If any overload is imposed on the motor by undue resistance from any cause to the normal movements of the washing or wringing mechanism, the excessive electric current thus occasioned in the motor windings 1S liable to burn it out. The object of this invention is to inter-pose intermediate the motor shaft and the machines driven thereby a protective coupling amply sufficient to, perform the normal-work of the machine but which will yield under excessive strain and permit slippage, thus preventing disastrous results to the motor windings.
The invention comprises a safety mechanism for motor from any leakage. When water will fall over motor due to leakage, it can cause short circuit and even bursting of motor. The safety mechanism is simple and cost effective and also alarm is linked with the safety mechanism in order to warn the user about leakage over motor. Whereas the compared invention is linked with the motor safety from overload which can cause short circuit and motor burn out.
Existing motor safety mechanisms in semi-automatic washing machines either have complex mechanisms or involve leakage prevention which does not involve efficient motor safety. Also, there is no alarm facility, only the machine is being cut off from the power supply and hence not suitable. Thus none of the prior art patents can be said to anticipate present invention.
INNOVATIVE SOLUTION PROPOSED BY INVENTORS:
The present invention is developed to keep the motors of semi-automatic washing machine safe from water leakage which can cause short circuit or burning of motor windings. A cost effective and simple safety mechanism is being provided in this invention along with
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provision of alarm associated with any problem linked with the water leakage on motor. The invention involves a piece of rubber with 3 strips placed on the top of the motor and is supported by the metal frame which covers the motor from the sides. At the center of the rubber a bush is placed which is connected to the motor through shaft. Two wires have been attached to the rubber piece in such a way to form a circuit so that it if there is water leakage from dryer seal and water fall over the rubber piece then wires get automatically connected through water and dryer motor will stop working and generates an alarm signal which shows that there is a problem in dryer seal.
OBJECTS OF THE PRESENT INVENTION
1. The primary object of the present invention is to disclose a simple and cost effective mechanism to keep the motor of the semi-automatic washing machine, safe from any water leakage.
2. Another object of the present invention is to disclose a mechanism with a provision of alarm signal so that the user is informed and get alert with alarm when any problem is being associated with the water leakage over the motor.
SUMMARY OF THE PRESENT INVENTION
In the present invention, the inventor has developed a simple and cost effective method for keeping the motor safe from any water leakage inside the semi-automatic washing machine. The leakage over motor can cause short circuiting and even burning of motor windings. The mechanism involves a piece of rubber with 3 strips placed on the top of the motor and is supported by the metal frame which covers the motor from the sides. At the center of the rubber a bush is placed which is connected to the motor through shaft. Two wires have been attached to the rubber piece in such a way to form a circuit so that it if there is water leakage
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from dryer seal and water falls over the rubber piece then wires get automatically connected through water and dryer motor will stop working and generates an alarm signal which shows that there is a problem in dryer seal. BRIEF DESCRIPTION OF THE DRAWINGS
FIG 1: Reference figure indicating parts of a normal existing washing machine
FIG 2: Schematic diagram of parts of washing machine of present invention
Numbering Details:
1. Motor
2. Safety system
3. Outer body
4. Dryer tub
5. Dryer drum
FIG 3A AND B: Safety mechanism of present invention
Numbering Details:
1. Rubber piece
2. Metal frame
3. Wires for signal
4. Bush
5. Leg for mounting
6. Area for leaked water storage
FIG 4: Representative diagram of electronic circuit used in the machine of present invention
Numbering Details:
1,2. AC power supply 220V
3,4. AC with lower voltage
5,6. DC supply
7,8. Signal receiving wire
9,10. Alarm wire
11,12. AC power supply 220V for dryer motor
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13. PCB plate for circuit
14. Step down transformer
15. Transistor
16. Resistance
17. Rectifier
FIG 5: Rear view of machine of present invention
Numbering Details:
1. Outer body
2. Signal wires / circuit wires
3. Safety system
4. Circuit holding box
DETAILED DESCRIPTION OF THE INVENTION
The present invention is designed to provide a safety mechanism for motor in semi-automatic washing machines to protect the motor from water leakage inside the machine. Referring to figure 2, schematic diagram of general parts of washing machine are shown; motor (1), safety system (2), outer body (3), dryer tub (4) and dryer drum (5). The motor is placed at the bottom in the side of dryer drum but eccentric to the center so that if there is water leakage, it does not fall directly on the motor. Instead it falls in the specially provided area (6) where it can be stored.
Referring to figure 3, the safety mechanism is shown; rubber piece (1), metal frame (2), wires for signal (3), bush (4) and leg for mounting (5). The safety mechanism provided by the inventor includes: a rubber piece which covers the top of the motor, the metal frame covers the motor from sides of the motor and it provide support to the rubber piece. A bush is placed over the rubber piece which is connected to the motor through the shaft. Two wires have been attached to the rubber piece in such a way to form a circuit so that if there is water leakage from dryer seal and water fall over the rubber piece then wires get automatically
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connected through water and dryer motor will stop working and generates an alarm signal which shows that there is a problem in dryer seal. Legs have been attached to the metal frame to facilitate the mounting of the system. A provision is there for storing the leaked water (6).
Referring to figure 4, it depicts the representative diagram of electronic circuit used in the machine. The circuit includes: AC power supply 220V (1, 2), AC with lower voltage (3, 4), DC supply (5, 6), signal receiving wire (7, 8), alarm wire (9, 10), AC power supply 220V for dryer motor, PCB plate for circuit (13), step down transformer (14), transistor (15), resistance (16) and rectifier (17).
Referring to figure 5, it shows the back side of the machine. The diagram consists of outer body (1), signal wires / circuit wires (2), safety system (3) and circuit holding box (4).
NOVELTY:
The novelty of the present invention lies in developing a simple and cost effective method for the motor safety from water leakage inside the semi-automatic washing machine and preventing short circuiting of motor or even burning of motor windings. The novelty also lies in providing an alarm signal when there is any problem faced by motor due to water leakage over motor.
INVENTIVE STEP:
The inventive step of the present invention lies in developing a safety mechanism for motors of semi-automatic washing machines which involves a piece of rubber which fits on a metal frame and a bush is placed at the center of the rubber piece which is connected to the motor through shaft. The rubber piece with three strips has been placed on the top of the motor. A circuit consists of two wires placed in such a way that if there is water leakage from dryer seal then wires get automatically connected through water and dryer motor will stop working and generates an alarm signal which shows that there is a problem in dryer seal.
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INDUSTRIAL APPLICATION:
The present application finds wide application in washing machine industry. The system is very simple to install and efficient for motor safety of semi-automatic washing machines at domestic level. The system can be sold as a cost effective accessory to prevent any short circuit associated with motor of the semi-automatic washing machine. Hence the mechanism finds a large industrial application in the washing machine industry.
In the preceding description, the invention is described with reference to exemplary drawings thereof. Various modifications and changes may be made thereto without departing from the broader spirit and scope of the invention as set forth in the claims. The specification and drawings are accordingly, to be regarded in an illustrative rather than a restrictive sense. Thus without analysis, the foregoing will so fully reveal the gist of the present invention that others can, by applying current knowledge, readily adapt it for various applications without omitting features that from the standpoint of prior art, fairly constitute essential characteristics of the generic or specific aspects of this invention.

I CLAIM:
1. A motor safety device for semi-automatic washing machine comprising a rubber piece (1 of Fig 3) covering the top of the motor, a metal frame (2 of Fig 3) covering the motor from sides and providing support to the rubber piece (1 of Fig 3) on the top, a bush (4 of Fig 3) placed over the rubber piece (1 of Fig 3) and is connected to the motor through the shaft, legs (5 of Fig 3) attached to the metal frame (2 of Fig 3) to facilitate the mounting of the system, two signal receiving wires(3 of Fig 3) attached to the rubber piece, two wires connected to electronic circuit for alarm wherein the safety mechanism works in such a way that if there is water leakage from dryer seal and water falls over the rubber piece (1 of Fig 3), then signal wires (3 of Fig 3) complete the circuit automatically through water and the motor stops working and generates an alarm signal .
2. The motor safety device for semi-automatic washing machine as claimed in claim 1 wherein the electronic circuit comprises of a normally available alarm circuit with buzzer.
3. The motor safety device for semi-automatic washing machine as claimed in claim 1 wherein a provision is there for storing the leaked water (6 of Fig 3).