Patent GB-720107-A (GB)
Title: Improvements in or relating to dish washing machines
IPC: A47L15/42
Filed: 1952-01-02
Abstract: 720,107. Dish-washing machines. NEW ZEALAND TEXTILE ENGINEERS, Ltd. Jan. 2, 1952 [Jan. 24, 1951], No. 189/52. Class 138 (1). In a dish-washing machine of the type comprising a motor driven impeller within a bowl, a manual control adapted to close a drain valve and the motor circuit and open a water supply valve, means to automatically close the water valve when the bowl is charged with water whereafter the machine will continue to operate until stopped manually and wherein the manual control comprises a knob or the like, cam means operable by the knob, follower means controlled by the cam means and adapted to control the drain valve and motor circuit and actuating means operable from the knob adapted to open the water valve, the means to ensure that the water valve will remain open to charge the bowl with water comprises locking means for locking the actuating means with the water valve open, setting means operable by continued movement of the knob when the machine is being put into operation in order to set the locking means and mechanical time lag mechanism adapted to be set mechanically by the setting means and to automatically release the locking means after a predetermined length of time so that the water valve will then close. The knob 12, Fig. 3, is detachably connected to a double cam 15, 15a pivotally mounted on a shaft 13 fixed to a base plate 14. The cam which is of substantially cylindrical shape has two opposed flat portions 15e, 15f, and an extension 15b. Two rockers 17, 18, Fig. 1, pivoted at 16 to the plate 14 have rollers 17a, 18a which co-operate with the cam surfaces having the flats 15e and 15f respectively. The rocker 17 is connected by a Bowden cable 6 to a pivoted lever 4, Fig. 2, operatively associated with the drain valve 1 mounted in the bottom of the bowl. The valve 1 is normally urged to the open position by the lever 4 through the action of a spring 5 and is closed by the cable 6 operating the lever 4 against the action of the spring 5. Lateral movement of the lever 4 in its guide plate 9 is prevented. The valve 1 has an overflow passage therethrough and an overflow tube 2 connected to the passage. The rocker 18 is connected by a link 19 to a switch 20 for the impeller motor circuit and is spring loaded at 20a to hold the roller 18a towards the cam. An actuating crank 21 is also pivotally mounted on the shaft 13 and is connected by a link 29 to the valve stem 10b of the water valve 10 which is in communication with a supply of hot water. The crank 21 and stem 10b are urged downwardly by a spring 11 to normally close the valve. A bearing plate 21a is provided on the crank 21 to be engageable by the cam projection 15b. A degree of free movement is provided between the double cam and the crank 21 so that when the valve 10 is closed the cam can be operated to stop the machine without affecting the crank. A known type of time lag mechanism 25, adjustable by a knob 25a, is coupled to a locking lever 23 pivoted at 24 to the plate 14 and urged downwardly by a spring 26. The lever 23 has a stop member 28 for engagement with a roller 27 on the crank 21 when in the raised position. A side projection 22 constituting the setting means is also provided on the crank to engage with the lever 23 to raise it when the crank is pivoted upwardly. In operation when the knob 12 is turned to move the double cam to the position shown in Fig. 1, the drain valve is closed the impeller motor is switched on and on further rotation of the knob the projection 15b finally causes the crank 21 to lift the lever 23. The crank is then locked by the co-operating roller 27 and stop 28 and the valve 10 remains open until the time lag mechanism releases the lever 23 which in turn releases the crank. The cam is notched at 15h and 15i so that it can be set in two positions, one in which the valve 1 is closed and the motor and valve 10 are cut off and in the other the valve 1 and motor circuit are opened and the valve 10 is cut off. In the first position access may be had to the bowl without draining the water therefrom. The knob may be operated to close the drain valve and the motor circuit without opening the water valve so that a current of air can be generated by the impeller to assist in drying the dishes. Specification 720,139 is referred to.