EP0095446A1

EP0095446A1 - Alternating supply device for the spray arms on a dishwashing-machine

Info

Publication number: EP0095446A1
Application number: EP83830102A
Authority: EP
Inventors: Marcello Premoli
Original assignee: Indesit Industria Elettrodomestici Italiana SpA
Current assignee: Indesit Industria Elettrodomestici Italiana SpA
Priority date: 1982-05-26
Filing date: 1983-05-24
Publication date: 1983-11-30
Also published as: IT1156020B; IT8267676A0

Abstract

The present invention relates to an alternating supply device for the spray arms on a dishwashing-machine which is fitted inside the end of the supply pipe (1), one outlet of which comes out directly inside one of the spray arms (12), while the other is designed so as to create a free jet for the other spray arm.

The said device also provides for adjusting the ratio between the amount of water supplied to one spray arm and the amount sent to the other spray arm, while a preferred solution is activated by one of the spray arms themselves via an appropriate gear mechanism.

Description

The present invention relates to a dishwashing-machine comprising a wash pump, a water supply pipe, a wash chamber, at least one bottom spray arm and a top spray arm inside the wash chamber and a device for supplying the spray arms alternately with one inlet and two outlets for water.
One of the problems posed by dishwashing-machines is to cut down on the amount of water and electricity required for the wash cycles.
For this purpose, certain types of known dishwashing-machines with more than one wash basket provide for supplying the two spray arms alternately.
In this way, washing efficiency for a given wash cycle is unimpaired, the amount of water required is reduced and a less powerful wash pump can be used for reducing electricity consumption both for operating the pump motor and heating the water.
A number of devices for supplying the two spray arms alternately as described above are already known, but they all present the same drawback of having to be controlled from outside the casing in which the water flows, which raises the obvious problem of sealing the casing to withstand the internal pressure exerted by the water at the point where the control device comes out.
A further drawback is seizing or jamming of the control device caused by waste food or scale in the wash water. During the washing operation, these get inside the sealing points so as to cause the said seizing when the water is drained off and the inside parts of the appliance dry off.
A further complication the said devices usually involve is that the control is, in turn, controlled by an additional electric motor of electromagnet.
Italian Patent Application N. 67133-A/81 of 2/2/1981, filed by the present applicant, describes a device for supplying the two spray arms alternately which is housed entirely inside the water supply casing and which solves the above-mentioned drawbacks. However, as it comprises a gear wheel and crown which engage with each other, dirt would be deposited between the teeth of the said gear wheel and crown thus making engagement of the two difficult.
Finally, all the abovementioned devices are used on dishwashing-machines on which the spray arms are supplied by two water supply pipes, that is, they are unsuitable for use on machines in which the top spray arm is supplied by a free jet of water from the bottom spray arm.
Furthermore, the said devices operate alternately, that is, supplying either the bottom or top spray arm, and no provision is made for regulating the supply of water to the two spray arms, i.e. all the water is supplied to one or the other of the spray arms.
The aim of the present invention is therefore to overcome the above drawbacks by providing a device for supplying the spray arms on a dishwashing-machine alternately which involves no problems of sealing or seizing, which can also be used on machines in which the top spray arm is supplied by a free jet and which provides for regulating the supply of water to the said spray arms.
With these aims in view, the present invention relates to a dishwashing-machine comprising a wash pump, a water supply pipe, a wash chamber, at least one bottom spray arm and a top spray arm inside the wash chamber and a device for supplying the spray arms alternately with one inlet and two outlets for water, characterised by the fact that the device for supplying the spray arms alternately is fitted- inside the end of the supply pipe and that one of the two outlets on the alternating supply device comes out directly inside one of the two spray arms.
The invention will now be described with reference to the attached drawing provided by way of a non-limiting example.
The diagram shows a cross section, cut off at the sides (the right half showing a variation) and a horizontal section of the device for supplying the spray arms on a dishwashing-machine alternately, as covered by the present invention.
It shows a supply pipe 1 with a pin support 2 in the middle, fitted to the said supply pipe 1 by means of tabs 3, rectangular side windows 4 on its side walls, trapezoidal top windows 5 on its top wall (shown more clearly in section A-A) and a gear wheel support 6 below side windows 4. Gear wheel support 6 has a centre pin, not shown in the diagram, on which is fitted gear wheel 7. The top of supply pipe 1 is fitted with a cap 8, assembled so as to turn round the said pipe, with rectangular side window covers 9, trapezoidal top window covers 10 (shown more clearly in section A-A) and external teeth 11 arranged so as to engage with the teeth on gear wheel 7. The bottom of bottom spray arm 12 presents a dog 13 located so as to engage with the teeth on gear wheel 7. Spray arm 14 is fitted on a steel pin 15 which, in turn is fitted on to pin support 2 the top end of which is threaded (not shown in the diagram). Nut 16 is screwed on to the threaded part of pin 15 to establish the upward travel of spray arm 14 which, in turn, establishes the travel of cap 8.
Finally, a jet director 17 is fitted on to spray arm 14.
The side 4 and top 5 windows on supply pipe 1 are aligned whereas the side 9 and top 10 window covers on cap 8 are offset in relation to one another. Furthermore, the said window covers are sized so that with cap 8 in a first position, side window covers 9 provide for maximum water flow through side windows 4 and top window covers 10 for minimum water flow through top windows 5 (they may even be closed entirely). With cap 8 in a second position, side a window covers 9 provide for minimum flow of water through side windows 4 (which, however, must not be closed entirely, as explained later) and top window covers 10 for maximum flow through top windows 10.
The maximum and minimum opening provide by side window covers 9 overlapping side windows 4 and top window covers 10 overlapping top windows 5 is regulated by suitable adjustment, during assembly, of the initial position of cap 8 on supply pipe 1.
A preferred operating arrangement could be one in which a first position of cap 8 provides for a maximum opening between side windows 4 and side window covers 9 and complete closure of the opening between top windows 5 and top window covers 10 (in which case, only bottom spray arm 12 is supplied), whereas a second position of cap 8 provides for half the maximum possible opening between side windows 4 and side window covers 9 and also between top window 5 and top window covers 10 (in which case both spray arms are supplied with the same amount of water).
To give a clearer explanation of how the device works, we shall start with a maximum possible opening between side windows 4 and side window covers 9 and a minimum possible opening between top windows 5 and top window covers 10.
When water flows along supply pipe 1, most of it flows through side windows 4 into bottom spray arm 12 which starts to rotate.
For each turn of bottom spray arm 12, dog 14 engages a tooth on gear wheel 7 which it moves round one step. Via one of teeth 11 with which one of the teeth on gear wheel 7 engages, the said rotary movement is transmitted to cap 8 which is also turned round one step.
In other words, each time bottom spray arm 12 is turned, cap 8 is also turned one step so as to reduce the opening on the side water inlets and increase the opening on the top water inlets until, gradually, side window covers 9 provide for maximum coverage of side windows 4 and top window covers 10 for minimum coverage of top window 5. Side windows 4, however, must not be closed off entirely, in that, if this should happen, water supply to bottom spray arm 12 would be cut off, spray arm would stop and with it the switching device.
Under these conditions, therefore, the top spray arm receives maximum water supply and the bottom spray arm the minimum.
As cap 8 continues to move round, it gradually increases the opening of side window 4 and reduces the opening of top window 5 until the starting condition is reached once more, i.e. minimum water supply to the top spray arm and maximum to the bottom spray arm.
As cap 8 moves round again, it gradually increases the opening of the side water inlets and reduces the opening of the top water inlets until the starting condition is reached once more, i.e. minimum water -supply to the top spray arm and maximum to the bottom spray arm.
As it turns round supply pipe 1, cap 8 thus controls alternate supply of the two spray arms on the dishwashing-machine.
The water coming out of top windows 5 forms a free jet which is sent through jet director 17 to supply the top spray arm not shown in the diagram.
As already demonstrated, the switch from minimum to maximum opening of side windows and side window covers 4-9 and top windows and top window covers 5-10 is made step by step, but it can also be triggered by merely providing for a counter mechanism which triggers cap 8 every so many turns of bottom spray arm 12.
The frequency with which supply is alternated depends on the ratio between the number of teeth on gear wheel 7 and the number of teeth 11 on cap 8.
The amount of water supplied to the spray arms can be regulated by adjusting the ratio and size of the side 4 and top 5 windows and the side 9 and top 10 window covers.
In an alternative arrangement, shown on the right of the diagram, cap 8 presents a control arm 18 with a centre notch 19 in which fits a pin 20 on which is fitted one end of a connecting rod 21 the other end of which is connected, via shaft 22, to one end of arm 23, the other end of which is connected, via a second pin 24, to a control element 25 which provides for only two settings corresponding to two settings on cap 8.
Control unit 25 may be of any type, e.g. an electromagnet, and is, in turn, controlled by a timer on the dishwashing-machine which also controls the frequency with which supply is alternated. Shaft 22 issuing from the wash chamber is fitted with a seal 26 to make it perfectly watertight.
As the water pressure in the wash chamber is much lower than in supply-pipe 1, sealing poses fewer problems than if the said shaft 22 passed through supply pipe 1 itself (as in the case of the known technique).
During operation, the frequency with which supply is alternated is controlled by the timer on the dishwashing-machine which controls energizing of the electromagnet on control unit 25 which, via second pin 24, arm 23, shaft 22, connecting rod 21, pin 20 and control arm 18, trasmits the motion to cap 8 which switches from one setting to the other.
This alternative arrangement provides for either complete switching, i.e. side windows 4 fully closed and top windows 5 fully open and vice versa, or partial switching in which minimum opening of side windows 4 corresponds to maximum opening of top windows 5 and vice versa, in which the said minimum and maximum openings are regulated by merely adjusting the size and initial position of the side 4 and top 5 windows and the side 9 and top 10 window covers.
The advantages of the device for supplying the spray arms on a dishwashing-machine alternately, covered by the present invention will be clear from the description given. In particular, the possibility of switching supply with no sealing or seizing problems, the possibility of also using the device on dishwashing-machines on which the top spray arm is supplied by a free jet, and, finally, the possibility of regulating the supply of water to the two spray arms.
To those skilled in the art it will be clear that numerous changes can be made to the device described by way of a non-limiting example without, however, departing from the scope of the present invention.

Claims

1. Dishwashing-machine comprising a wash pump, a water supply pipe, a wash chamber, at least one bottom spray arm and a top spray arm inside the wash chamber and a device for supplying the spray arms alternately with one inlet and two outlets for water, characterised by the fact that the device for supplying the spray arms alternately is fitted inside the end of the supply pipe (1) and that one of the two outlets on the alternating supply device comes out directly inside one of the two spray arms.

2. Dishwashing-machine according to Claim 1, characterised by the fact that the said alternating supply device is formed using the end of the said supply pipe (1) in which openings are made for obtaining one of the said two water outlets on the said device for supplying the spray arms alternately.

3. Dishwashing-machine according to Claim 2, characterised by the fact that the said alternating supply device comprises closing means (8) for closing the said openings and, at the same time, enabling water to be conveyed towards a route constituting the second of the said two outlets on the said device for suppling the spray arms alternately.

4. Dishwashing-machine according to Claim 3, characterised by the fact that the said supply pipe (1) in the said route constituting the said second of the said outlets presents partial openings which, together with the openings on the said closing means (8), form the said second water outlet.

5. Dishwashing-machine according to Claim 4, characterised by the fact that the said openings on the said supply pipe (1) and the said openings on the said closing means (8) are positioned in relation to one another so that, with the said closing means (8) in a first position, a maximum supply of water is sent to the said first outlet and a minimum supply to the said second outlet on the said device for supplying the spray arms alternatively, while, with the said closing means (8) in a second position, a minimum supply of water is sent to the said first outlet and a maximum supply to the said second outlet on the said device for supplying the spray arms alternatively.

6. Dishwashing-machine according to Claim 5, characterised by the fact that the said initial position of the said openings on the said supply pipe (1) and the said openings on the said closing means (8) can be adjusted so as to regulate the ratio uetween the amount of water supplied to one of the said two outlets and the amount of water supplied to the other of the said two outlets on the said device for supplying the spray arms alternatively.

7. Dishwashing-machine according to Claim 4, characterised by the fact that the said openings forming the said first water outlet are made in the side end of the said supply pipe (1) and consist of side windows (4), and that the said partial openings forming the said second water outlet are made in the top end of the said supply pipe (1) and consist of top windows (5).'

8. Dishwashing-machine according to Claim 3, characterised by the fact that the said closing means comprise a cap (8) with side window covers (9) and top window covers (10).

9. Dishwashing-machine according to Claim 8, characterised by the fact that the said cap (8) is fitted round the said supply pipe (1) and that it can rotate around it.

10. Dishwashing-machine according to Claim 8, characterised by the fact that the said side (9) and top (10) window covers on the said cap (8) are located and sized so that, with the said cap (8) in a first position, a maximum water opening is provided for on the first of the said two outlets on the supply pipe (1) and a minimum water opening on the second of the said two outlets on the said supply pipe (1), whereas, with the said cap (8) in a second position, a minimum water opening is provided for on the first of the said two outlets on the said supply pipe (1) and a maximum water opening on the second of the said two outlets on the said water pipe (1).

11. Dishwashing-machine according to Claim 10,characterised by the fact that the said first position of the said cap (8) corresponds to a position of the said side (9) and top (10) window covers in which a maximum supply of water is sent to the said first outlet on the said supply pipe (1) and practically no water supplied to the said second outlet on the said supply pipe (1), whereas, the said second position of the said cap (8) corresponds to a position of the said side (9) and top (10) window covers in which half the maximum supply of water is sent to both the said outlets on the said supply pipe (1).

12. Dishwashing-machine according to Claim 7, characterised by the fact that the said side windows (4) and the said side window covers (9) are rectangular in shape and that the said top windows (5) and the said top window covers (10) are trapezoidal in shape.

13. Dishwashing-machine according to Claim 3, characterised by the fact that the said second outlet on the said rotary manifold supply device provides for the formation of a free jet of water for supplying the top spray arm.

₁₄. Dishwashing-machine according to Claim 9, characterised by the fact that the said cap (8) is turned by control means housed entirely inside the said washing chamber.

15. Dishwashing-machine according to Claim 14, characterised by the fact that the said control means comprise a gear wheel (7) which engages with teeth (11) on the said cap (8).

16. Dishwashing-machine according to Claim 15, characterised by the fact that the said gear wheel (7) rests on a gear wheel support on the said supply pipe (1) and is activated by a dog (13) integral with the said bottom rotary manifold (12).

17. Dishwashing-machine according to Claim 15, characterised by the fact that the frequency with which the said cap (8) is turned is determined by the ratio between the number of teeth on the gear wheel (7) and the number of teeth (11) on the said cap (8).

18. Dishwashing-machine according to Claim 9, characterised by the fact that it comprises means for activating the said cap (8), the said means being partly inside and partly outside the said washing chamber.

19. Dishwashing-machine according to Claim 18, characterised by the fact that the said first position of the said cap (8) corresponds to a maximum opening on the said first outlet and practically no opening on the said second outlet on the device for supplying the spray arms alternatively, whereas, the said second position of the said cap (8) corresponds to practically no opening on the said first outlet and a maximum opening on the said second outlet on the said device for supplying the spray arms alternatively.

20. Dishwashing-machine according to Claim 18, characterised by the fact that the said control means comprise a control arm (18) on the said cap (8), a connecting rod (21), a drive shaft (22), a pin (24) and a control unit (25).

21. Dishwashing-machine according to Claim 20, characterised by the fact that the said drive shaft (22) is fitted with a seal (26) at the point where it comes out of the said washing chamber.

22. Dishwashing-machine according to Claim 20, characterised by the fact that the said control unit (25) has only two positions and that, via pin 24, shaft 22, connecting rod 21 and control arm 18, its two positions are transmitted to the said cap (8) to switch its positions alternatively.

23. Dishwashing-machine according to Claim 22, characterised by the fact that the frequency of the said switching is determined by the timer on the dishwashing-machine itself which controls the said control unit (25).