GB2087717A

GB2087717A - Dishwasher and method of controlling operation of same

Info

Publication number: GB2087717A
Application number: GB8118753A
Authority: GB
Original assignee: Chemed Corp
Current assignee: Chemed Corp
Priority date: 1980-11-12
Filing date: 1981-06-18
Publication date: 1982-06-03
Also published as: ES8206174A1; IT8124105A0; AU7403181A; JPS5793029A; NL8103337A; DE3135059A1; FR2493694A1; ZA814297B; ES507031A0; IT1138234B

Abstract

A dishwasher 13 comprising a conveyor 37 has a lever 15 disposed in the path of a tray 33 loaded with dishes 35 to be washed, the end 27 of the lever having a magnet 29 which actuates a magnetic switch 31 when the lever is tripped by the tray. The magnetic switch is connected to a timing mechanism 41 which allows the pumps, final rinse cycle and conveyor to operate for a predetermined amount of time. If a second tray contacts the lever prior to the expiration of the first time cycle, the timing mechanism is reset. <IMAGE>

Description

SPECIFICATION Dishwasher and method of controlling operation of same This invention relates to dishwashers and more particularly to a control mechanism for controlling the time of operation of a conveyor type dishwasher.

Many dishwashers, for use in restaurants or other commercial establishments or institutions, utilize a conveyor belt on which a tray or dishrack carrying dishes is carries through the wash and rinse cycles.

Such dishwashers may be kept running at all times, or be manually controlled by an operator or the person loading the dishes. That type of operation results in the dishwasher running during periods when no dishes are being processed through the dishwasher, which in turn results in the waste of water and electricity.

Timing mechanisms have been suggested for dishwashers and rinsing machines. For example U.S.

Patent No. 3,071,144 (Hilliker) describes an actuation mechanism for a preliminary rinsing machine. The apparatus described in that patent utilizes mechanical means to activate mechanically microswitch blades and a solenoid valve which provides the supply of water. A time delay is provided by utilizing a bellows which allows a sufficiently long period of time for a dish to travel through the rinsing machine.

The apparatus described has the disadvantage that the time delay cannot be reset if a new dish begins the wetting process prior to the termination of the wetting of the first dish.

The invention aims to provide for controlling the operation of a conveyor type dishwasher so as to enable activation and resetting of a timing mechanism controlling the operation of the dishwasher.

Accordingly one aspect of the present invention provides a dishwasher having a conveyor adapted to move trays with soiled dishes and a timing mechanism to activate pumps, final rinse cycle and the con veyorfor a predetermined amount of time, comprising: a bracket secured to a wall in the dishwasher; a pivot attached to the bracket; a dishrack lever rotatably mounted on the pivot and having a first end disposed on the path of such a tray on the conveyor so that such tray will force the dishrack lever to rotate about the pivot when the tray contacts the dishrack lever; a magnet attached to a second end of the dishrack lever; and means responsive to proximity of the magnet thereto and disposed on the dishwasher for activating and resetting the timing mechanism whereby the timing mechanism is activated and reset whenever a tray trips the dish rack lever.

A second aspect of the invention provides a method of controlling the operation of a dishwasher having a conveyor, comprising the steps of: moving a tray of soiled dishes into contact with a dishrack lever which is disposed on the path of the conveyor and has a magnet on one end; pivoting the dishrack lever by said contacting to bring the magnet in proximity to a magnetic switch to create a signal; and activating a timing mechanism with said signal, whereby the washing functions of the dishwasher are in operation for a predetermined amount of time each time a said signal is generated by the magnetic switch.

In order that the present invention may more readily be understood, one embodiment thereof will now be described below with reference to the accompanying drawing in which: FIGURE 1 is a side view of the control mechanism of a dishwasher constructed in accordance with the present invention: FIGURE 2 illustrates the activation of the control mechanism; FIGURE 3 is a detail of the magnetic switch mechanism; and FIGURE 4 is a front view of the magnetic switch of the control mechanism.

As illustrated in Figure 1, and also in greater detail in Figure 3, the control mechanism 11 for a dishwasher 13 includes a dishrack lever 15 which is attached to a bracket 17 by means of a pivot 19. The bracket 17 is attached to a wall 21 of the dishwasher 13 by bolts 23 and 24. The dishrack lever 15 has a first cam-like end 25 having a substantially smooth gradual shape. The first end 25 is oriented substantially perpendicular to the axis of the pivot 19. Dishrack lever 15 also includes a second end 27 which is disposed substantially parallel to the axis of pivot 19.

Dishrack lever 15 may be integrally formed of a bar of non-magnetic material which is twisted through 90 . A magnet 29 is attached to the second end 27 of dishrack lever 15. The combined mass of the magnet 29 and the dishrack lever 15 should be sufficiently great to gravity bias dishrack lever 15 to be substantially vertical as shown. A magnetic switch 31, which sends a signal whenever magnet 29 is in close proximity, is secured to the exterior portion of the wall 21.

The operation of the system is best illustrated by means of Figures 1 and 2 in which a dishrack 33 containing a plurality of dishes 35 is disposed on a conveyor 37 supported by a dish table 39.

Initially the magnetic switch 31 is deactivated, since the magnet 29 is disposed a substantial distance away from it. Atiming mechanism 41 is electrically coupled to the magnetic switch 31 and is electrically connected to the motors and pumps and to all other equipment which performs the dishwashing functions of the dishwasher 13. Thus the timing mechanism 41 controls the operation of the dishwasher.

Assuming that the timing mechanism 41 has not yet been activated, it is activated by manually pushing dishrack 33 until it comes into contact with the camlike surface 25 of dish rack lever 15. The motion of the dishrack 33 then forces the lever arm 15 to pivot anti-clockwise about pivot 19 (as indicated by arrow "A" in Figure 2) and causes magnet 29 to come into proximity with magnetic switch 31. At that time magnetic switch 31 would normally create a signal to activatethetiming mechanism 41 which would in turn start the motors, pumps and other equipment controlled by the timing mechanism, for a predetermined amount of time.

If, however, the timing mechanism 41 has been actuated when a second dishrack 33 is inserted into the system the timing mechanism will be automatically reset to the start position. This can be accomplished by merely putting a new dishrack 33 on the conveyor 37 which will then pull that new dishrack into contact with dishrack lever 15. Magnet 29 will then activate magnetic switch 31 which would reset the timing mechanism 41 The motors, pumps, and other equipment then operate for the set period desired.

The period of time for which the timing mechanism would be set to run is that period of time required forthe dishrack to complete a washing, rinsing and drying cycle.

The preceding description is given merely by way of example and is capable of being subjected to certain changes without departing from the scope of the invention as claimed. Thus all matter contained in the above description or shown in the accompanying drawing shall be interpreted as illustrative and not in a limiting sense.

Claims

1. A dishwasher having a conveyor adapted to move trays with soiled dishes and a timing mechanism to activate pumps, final rinse cycle and the conveyor for a predetermined amount of time, comprising: a bracket secured to a wall in the dishwasher; a pivot attached to the bracket; a dish rack lever rotatably mounted on the pivot and having a first end disposed on the path of such a tray on the conveyor so that such a tray will force the dishrack lever to rotate about the pivot when the tray contacts the dishrack lever; a magnet attached to a second end of the dishrack lever; and means responsive to proximity of the magnet thereto and disposed on the dishwasher for activating and resetting the timing mechanism whereby the timing mechanism is activated and reset whenever a tray trips the dish rack lever.

2. The improvement of claim 1, wherein the dishrack lever is made of non-magnetic material.

3. A dishwasher according to claim 1 or 2, wherein the bracket is secured on an interior wall of the dishwasher.

4. A dishwasher according to claim 3, wherein the means for activating and resetting is mounted on the exterior of the dishwasher.

5. A dishwasher according to any one of The preceding claims, wherein said means for activating and resetting comprises a magnetic switch connected to the timing mechanism.

6. A dishwasher according to the preceding claims, wherein the dishrack lever is gravity biased to adopt a position in which the first end of the lever projects into the path of a tray carried by the conveyor and in said position the magnet is spaced from the activating and resetting means.

7. A dishwasher constructed and adapted to operate substantially as hereinbefore described with reference to and as illustrated in the accompanying drawings;

8. A method of controlling the operation of a dishwasher having a conveyor, comprising the steps of: moving a tray of soiled dishes into contact with a dishrack lever which is disposed on the path of the conveyor and has a magnet on one end; pivoting the dishrack lever by said contacting to bring the magnet in proximity to a magnetic switch to create a signal; and activating a timing mechanism with said signal, whereby the washing functions of the dishwasher are in operation for a predetermined amount of time each time a said signal is generated by the magnetic switch.

9. A method of controlling a dishwasher substantially as hereinbefore described with reference to the accompanying drawing.

New claims filed on 10 Feb. 1982 Newclaims:-10, 11,12.

10. A dishwashing machine having a timing mechanism to shut off the machine after each cycle and to automatically reset the timing mechanism when a new tray of dishes is inserted into the machine comprising a dishwashing compartment with associated pump to spray a washing fluid; a dishrinsing compartment with associated pump to spray a rinsing fluid; a dishdrying compartment with associated means to dry the dishes; a conveyor mechanism to move trays with soiled dishes into and through said dishwashing, dishrinsing and dishdrying compartments; a bracket secured to an i nterior wall in said dishwashing compartment and near the entrance to said dishwashing compartment; a pivot attached to the bracket;; a dishrack lever rotatively mounted on the pivot and having a first end disposed on the path of a tray on the conveyor so that the tray will force the dishrack lever to rotate about the pivot when the tray contacts the dishrack lever; a magnet attached to a second end of the dishrack lever; a magnetic switch on the exterior of said dishwashing compartment spaced from said magnet attached to said second end of said dishrack lever; a timing mechanism to actuate the pumps in said dishwashing and dishrinsing compartments, to actuate said means to provide heated air to said dishdrying compartment and to actuate said conveyor mechanism; and connecting means connecting said magnetic switch to said timing mechanism whereby the timing mechanism is actuated and reset whenever a tray trips said dishrack lever.

11. The dishwasher machine according to Claim 10, wherein the dishrack lever is made of nonmagnetic material.

12. A method of controlling the operation of a dishwasher machine having a conveyor passing through at least a dishwashing compartment and a dishrinsing compartment and having a timing mechanism to shut off the machine after each cycle and to automatically reset the timing mechanism when a new tray of dishes is inserted into the machine comprising the steps of: disposed on the path of the conveyor as it enters the dishwashing compartment a dishrack lever having a magnet on one end; contacting the dishrack lever with a tray of soiled dishes; pivoting the dishrack lever to bring the magnet in proximity to a magnetic switch positioned on the exterior of the dishwashing compartment to create a signal; and activating the timing mechanism with the signal whereby the washing functions of the dishwasher are placed in operation for a predetermined amount of time each time the signal is generated bythe magnetic switch.