Patent GB-661124-A (GB)
Title: Improvements in or relating to dishwashing machines
IPC: A47L15/23
Filed: 1948-12-10
Abstract: 661,124. Dish-washing machines. AKTIEBOLAGET ELEKTROLUX. Dec. 10, 1948 [Dec. 20, 1947], No. 31961/48. Class 138 (i). [Also in Group XXIX] A dish-washing machine having one or more pairs of spraying devices includes an automatically operating control device adapted to admit liquid for alternately driving the two spraying devices of a pair and transmission means interconnecting the said spraying devices so that each in turn serves as a driving member for the other, while the inoperative spraying device acts as a brake for the driving spraying device. The machine comprises a washing housing 10, Fig. 1, in which are mounted upper and lower pairs of spraying devices 17 each including a spraying head 19 and jet diverting elements 28, Fig. 2, formed on a three armed support 18, in which the head 19 is rotatable in one direction by reaction of its jets while the support 18 is rotatable in the opposite direction by the force of the jets as is more fully described in Specification 633,496, [Group XXIII]. Each pair of supports 18 are formed with pulleys 29 interconnected by a crossed belt 30. Bosses 20 on which the heads 19 and supports 18 are mounted are supplied with liquid through pipes 21, 22, 23 and 24 from an automatic valve 25 mounted on the bottom of the machine and supplied with liquid through a pipe 26. In one position of the automatic valve the lower left hand and upper right hand spraying devices are actuated by the supply of liquid while the lower right hand and upper left hand supports 18 are driven idly by the crossed belts 30. In the other position of the valve the lower right hand and upper left hand spraying devices are actuated while the lower left hand and upper right hand supports are driven idly. This arrangement whereby the jet diverting elements are always driven in the same direction but idly rotated in the opposite direction ensures a varying speed of a liquid actuated spraying device so that the diverted sprays of liquid are issued in varying directions thereby enhancing the washing effect. Instead of the three-armed supports 18 having their arms 27 all curved in the same direction as shown in Fig. 2 the same washing effect may be achieved by making the supports of a pair, mirror like counterparts of one another and connecting them by a belt which is not crossed over. In another embodiment in which the above washing effect is achieved each spraying device consists of a straight pipe provided with oblique nozzle openings and the pairs are connected by an uncrossed belt. The automatic valve 25, Figs. 4 and 5, comprises a housing 37 having a cylindrical chamber 38 provided with three lateral channels 39, 40, 41 extending at right angles arid tangentially with respect to the' chamber, the central channel 39 constituting a supply conduit. The channels 40, 41 extend right through the chamber and form four discharge openings connected by the pipes 21, 22, 33 and 24, to the, spraying devices. The supply conduit is provided with a filter 43 and is also provided near the junction with the supply pipe 26 with obliquely drilled channels 49 and 50 connected by, pipes 51, 52 to a measuring apparatus for a washing agent (not shown). The ends of the chamber 38 also communicate by lateral channels 61, 62, Fig. 5, in the valve housing, with the channels 40, 41, respectively, the channel 62 being provided with a throttling valve on a screw spindle 63. Arranged within the chamber 38 are pairs of operating pistons 68 and reversing pistons 69. The operating pistons comprise heads 71, mounted at each end of a spindle 70, and associated with compression springs 74 which are clamped between the heads and washers 75 slid'able on. the spindle. The movement of the washers is limited by the reversing pistons and collars 76 on-the spindle according 'as'to the position of the reversin'<SP>g</SP>'<SP>p</SP>istons. The reversing pistons are slidable on'the spindle 70 and comprise cylindrical sections' 77'each integral with a central section 78. Channels 79 are provided at the junctures of the sections to allow passage therethrough of liquid. The section 78 comprises a central cylindrical member 81 bounded at each end by peripheral grooves 80. The grooves 80 are alternately engageable by a locking device (not shown) in the form of a spring pressed.piston provided with a roller for engaging in one or other of the grooves. The locking device is located in a boss extending obliquely from the valve housing. The pistons are shown in the operative position prior to the reversing movement. Liquid passes through the channel 40 to the respective spraying devices while the channel 41 is .closed. The space between the heads 71 is filled with liquid owing to the channels 79. Owing to the resistance to the flow of liquid in the pipes to the spraying devices a counter-pressure is created and liquid passes through the channel 61 to exert a pressure on the outer face of the left hand piston head 71. The left hand spring 74 is compressed during the movement of the head 71 to position shown in Fig. 4 when it bears against the left hand section 77 of the reversing piston. The liquid pressure in the central portion of the chamber 38 releases the locking device and the compressed left hand spring 74 moves the reversing pistons 69 to the right so that the channel 40 is closed and the channel 41 is opened. These operations are repeated and the time intervals between the valve reversals can be regulated by the throttling valve in the passage 62. In another embodiment, Fig. 9, piston heads 118 are connected by a tubular rod 119 and passing through bores in the pistons and the bore in the rod 119 is a valve device 117 in the form of a rod 122 having end screws 123, washers 124 and helical springs 125. An opening 121 is provided in the rod 119 so that liquid from the supply channel 103 can communicate with the ends of the cylindrical valve chamber 102. The washers 124 are alternately engageable with edges of recesses 110 in the end covers 109 of the valve housing. The recesses are in communication with adjustably throttled passages which in turn communicate with the washing chamber of the machine through channels formed in the screws fastening the valve housing to the bottom of the washing chamber. In the position shown liquid from the supply channel 103 is passed to the respective. spraying devices via a channel 105, and the right hand washer 124 is: seated against its corresponding recess 110. No pressure exists in the extreme left hand end of the valve chamber since liquid passing through the opening 121 is freely discharged through the open left hand recess 110 into the washing chamber. However liquid can enter the extreme right hand end of the valve chamber and thus cause the pistons to move to the left. The left hand piston 118 then compresses the left hand spring 125 until the force exerted by the spring overcomes the pressureof the liquid on the right hand washer 124, when the rod 122 is suddenly displaced .to the left to close the left hand recess 110 and open the right hand recess 110. The washing liquid then passes to the alternative spraying devices through a channel 104 and the pistons 118 are again reversed and the cycle repeated.