Patent GB-743786-A (GB)
Title: Improvements in mechanism for controlling the operation of laundry or textile washing, dyeing, bleaching or similar machines
IPC: D06F34/08
Filed: 1952-12-12
Abstract: 743,786. Washing-machines. FISHER, I. M. Dec. 14, 1953 [Dec. 12, 1952], No. 31481/52. Drawings to Specification. Class 138 (2). Mechanism for controlling the operation of a laundry and textile washing, dyeing, bleaching or similar machine, comprises an electromagnetically operated uniselector, a pair of contact banks of which, in conjunction with a set of switches, control the timing of the successive stages of an operating cycle and further contact banks of which are connected through preselector switches and relays to control the operating conditions of each stage. As applied to a washing-machine the uniselector has nine banks each of 25 contacts. Eight of the banks are used in pairs to provide four sets of 50 contacts. The uniselector is driven by a solenoid which is normally operated through a relay by a motor-driven switch having a rotating wiper and two diametrically opposite contacts. This is driven at the rate of one revolution every two minutes and the contacts therefore produce'current pulses at the rate of one per minute. Thus by using both pulsing contacts the uniselector wipers can be stepped one group of contacts per minute or by using one pulsing contact, the uniselector wipers are stepped once every two minutes. Timing.-One set of 50 uniselector contacts is used to control this in conjunction with the set of pre-selector switches. Three washing periods and four rinsing periods are used. Each period is provided with its own timing switch and the fixed contacts of each switch are each connected to a uniselector contact or in some cases to a group of uniselector contacts. Thus contacts 2-10 are connected to the timing switch for washing period 1 and contacts 11-19, 20-31, 32-37, 38-42, 43-47 and 48-50 respectively to the switch for the remaining two washing periods and the four rinsing periods ; contact 1 is used for operating a relay at the end of the machine cycle. The wiper of each timing switch successively connects the fixed contacts together and to a make and break contact which is operated by the uniselector driving solenoids and which is connected in series with a control relay for the uniselector in such a way as to form an alternative to the motor-driven switch for operating the uniselector control relay. The connections of each timing switch are such that the higher numbered uniselector contacts are first connected to the respective wipers, the lower numbered contacts being subsequently connected in reverse order as each timing switch wiper is rotated. Thus since each timing switch wiper is connected to the supply, the uniselector automatically steps itself over its contacts which are connected to the timing switch wiper, immediately it reaches the first one in a group and without waiting for pulses from the motordriven switch, until it reaches the first contact of the next group. The time of each washing and rinsing period is therefore fixed by the number of uniselector contacts which are not connected to the respective timing switch wiper since over such contacts the uniselector is stepped by the motor-driven switch at the rate of one every two minutes during the washing periods and one every minute in the rinsing periods (one contact of the motor-driven switch is disconnected in the washing periods as explained below). The whole of a group of uniselector contacts can be connected to the respective timing switch wiper so that any given washing or rinsing period can be omitted, if desired, since the uniselector will then step itself automatically over the whole group. Water supply.-A second set of fifty uniselector contacts is used to control the supply of cold water and a third set of fifty contacts for the supply of hot water. As regards the cold water supply separate switches for pre-selecting the amount of water for each washing and rinsing period are provided. The wipers of the switches are respectively connected to uniselector contacts 2, 11, 20, 32, 38, 43 and 48 and the switch contacts are connected to electrodes in the washing-machine which successively project into the machine to increasing depths. The longest electrode is also connected to one side of the supply, so that when any switch wiper is on the contact connected to this electrode no water is supplied. The uniselector wiper is connected through a relay coil to the other side of the supply. The relay contacts are connected so that the water-supply valve is open to supply water to the machine when the relay is unoperated. When the water reaches the selected electrode the relay coil circuit is completed and the operation of the relay shuts off the water valve. A second set of contacts of the relay are connected between the motordriven switch and the operating relay for the uniselector so that the uniselector is prevented from stepping until the selected amount of water is in the machine. The remaining contacts of the uniselector are connected so that when the uniselector wiper is on such contacts the relay is held operated. The hot water supply arrangements are identical. The electrodes in the washing-machine are common to both hot and cold water supplies but since the contacts of the two relays in the uniselector driving circuit are arranged in series the uniselector cannot move until both relays are operated even though if different electrodes are selected the relays will operate at different times. Soap, soda and detergent supply.-Some of the contacts in the fourth set of 50 uniselector contacts are used for this purpose. Uniselector contacts 2-9 are connected together and to a relay coil, contacts 11-18 are connected together and to a second relay coil, and contacts 20-30 are connected together and to a resistance. The two relay coils and the resistance are connected to a third relay coil. Thus on contacts 2-9 the first and third relays are operated, on contacts 11-18 the second and third relays are operated and on contacts 20-30 the third relay alone is operated. The supplies of soap, soda and detergent are contained in separate tanks and the volume delivered from the tanks is determined by electrodes of increasing lengths which project into the tanks. Each tank is provided with three selector switches one for each washing period and the electrodes are connected to the contacts of the switches which are connected in turn to the electric supply through valve control relay coils by the operation of the first and second relays previously mentioned. When the circuits are completed by the operation of these first and second relays current in each circuit flows through the liquid in the tank from an electrode connected to the supply to the electrode selected by the switch and thence through the valve control relay coil; current also flows through the valve control relay and from the coil of a cut-off relay connected in parallel with the tank electrodes this current being insufficient to operate the cut-off relay. The contacts of the valve control relay operate a valve which causes air to blow the liquid from the tank into the washing-machine. This continues until the level of liquid in the tank falls below the level of the selected electrode when the current in the tank ceases. This cessation causes the current through the cut-off relay coil to increase to operate it and its contacts short-circuit the valve control relay coil so that it ceases to operate and so shuts off the air valve. The third relay previously mentioned has one of its contact sets in the supply circuit to the valve control and cut-off relays so that they are restored to their original condition at the end of each washing cycle. A second contact set is in the circuit from one of the contacts of the motor-driven switch to the uniselector control relay so that the uniselector is stepped every two minutes instead of every minute. The supply circuit for the valve control relay of the soda tank is completed through some of the contacts of the remaining bank of 25 uniselector contacts so that the operation of the valve can take place at the same time as the other'two valves or be delayed by two minutes. The tanks refill during the washing period and each is provided with a guard relay which stops the operation of the uniselector by breaking the circuit of its control relay if filling is not completed at the end of the period. Each tank has an electrode connected to the guard relay coil through which a current can flow if the tank is full. At the end of each period a pair of contacts of a relay controlling the washing-machine drain valve close and the guard relays then operate if the tanks are full and complete a circuit to the uniselector control relay, the previous circuit having been broken by a second set of contacts of the drain valve relay. If any tank is not full a second set of contacts of its guard relay operate an alarm relay. Temperature control.-A multi-point thermostat is provided in the washing-machine the various points being connected to the contacts of three selector switches, one for each of the washing periods. The particular switch for a period is selected by further contacts of the two relays which control the soap &c. switches and the third relay mentioned in that connection has a set of change-over contacts in the coil circuit of a steam valve control relay. This relay is normally kept operated by these change-over contacts and when they change over at the beginning of a period by operation of said third relay as previously described they connect the steam valve control relay coil to the switch contacts. The steam valve control relay then releases and its contacts operate a steam valve to supply steam to the machine. When the temperature reaches the selected level the thermostat completes a circuit for the control relay which then operates and shuts off the supply of steam. Drain valve operation.-This is accomplished by contacts 10, 19, 31, 37, 42, 47 of the previously men