US3777989A

US3777989A - Dishwasher with cycle timing system

Info

Publication number: US3777989A
Application number: US00244114A
Authority: US
Inventors: G Pacella; R Eckman
Original assignee: Individual
Current assignee: Individual
Priority date: 1972-04-14
Filing date: 1972-04-14
Publication date: 1973-12-11
Anticipated expiration: 1990-12-11

Abstract

A cycle timing system for dishwasher apparatus controls the fill and drain sequence. A control shaft is manually rotated to wind a torsion spring and bias the control shaft for rotation in a first direction. This rotation is inhibited by a pair of detent arms which are biased towards a ratchet wheel mounted on the control shaft. Each detent arm is adapted to engage a tooth of the ratchet wheel, one arm being midway between a pair of adjacent teeth of the ratchet wheel when the other detent arm is engaged with a tooth of the ratchet wheel and vice versa. A float, which senses the level of water in the tube of the dishwasher apparatus, is mounted on a pivoted float arm which rotates a float arm rod having a float arm rod extension adapted to push one detent arm from the rachet wheel when the water level in the tub reaches a predetermined high level and to push the other detent arm from the ratchet wheel when the water level in the tub reaches a predetermined low level. When a detent arm is pushed from a tooth of the ratchet wheel, the control shaft is free to rotate in the first direction until a tooth of the ratchet wheel is engaged by the other detent arm. A control cam is mounted on the control shaft and actuates a valve control switch causing a valve to assume a fill or a drain position. The dishwasher includes a sprayer formed by a channel integral with the bottom wall of the tub and covered by a cover plate having a plurality of spray orifices.

Description

United States Patent [1 1 Pacella et al.

[ 1 Dec. 11, 1973 DISHWASHER WITH CYCLE TIMING SYSTEM [76] Inventors: Gerald M. Pacella, 100

Pennypacker Dr., Willingboro, NJ. 08046; Richard S. Eckman, 448D Garnet Mine Rd., Boothwyn, Pa. 19061 [22] Filed: Apr. 14, 1972 [21] Appl. No.: 244,114

[52] US. Cl. 239/567, 134/191, 137/446, 239/600 [51] Int. Cl B051) 1/18 158] Field of Search 137/446, 441; 239/567,19, 20,-23, 127, 600; 134/186, 199, 191, 198

[56] References Cited UNITED STATES PATENTS 1,938,302 12/1933 Snyder... 134/186 3,233,782 2/1966 Ullman Jr. et al.... 239/600 3,213,866 10/1965 Martiniak 239/567 3,394,718 7/1968 Wallgren et al. 239/567 3,595,253 7/1971 Pastor et al 239/567 3,401,717 9/1968 Lamb 137/446 3,385,317 5/1968 Yankers 137/446 Primary Examiner-Lloyd L. King Att0rney-Milton M. Field [57] ABSTRACT A cycle timing system for dishwasher apparatus controls the fill and drain sequence. A control shaft is manually rotated to wind a torsion spring and'bias the control shaft for rotation in a first direction. This rotation is inhibited by a pair of detent arms which are bi ased towards a ratchet wheel mounted on the control shaft. Each detent arm is adapted to engage a tooth of the ratchet wheel, one arm being midway between a pair of adjacent teeth of the ratchet wheel when the other detent arm is engaged with a tooth of the ratchet wheel and vice versa. A float, which senses the level of water in the tube of the dishwasher apparatus, is mounted on a pivoted float arm which rotates a float arm rod having a float arm rod extension adapted to push one detent arm from the rachet wheel when the water level in the tub reaches a predetermined high level and to push the other detent arm from the ratchet wheel when the water level in the tub reaches a predetermined low level, When a detent arm is pushed from a tooth of the ratchet wheel, the control shaft is free to rotate in the first direction until a tooth of the ratchet wheel is engaged by the other detent arm. A control cam is mounted on the control shaft and actuates a valve control switch causing a valve to assume a fill or a drain position. The dishwasher includes a sprayer formed by a channel integral with the bottom wall of the tub and covered by a cover plate having a plurality of spray orifices.

22 Claims, 9 Drawing Figures PATENFEI] DEC 1 1 I975 SHEET 10F 5 PATENIED ME 1 I 1973 SHEEI 2 UF 5 FAQ 4 2o SOLENOID AC k I56 VALVE 32 POWER NEON o SUPPLY CQPUMP kD H5 v N VALVE 28 H2 SWITCH I ue MANUAL CONTROL SW|TCH SWITCH PATENIED DEC 1 1 I973 SHEET 5 BF 5 DISHWASHER WITH CYCLE TIMING SYSTEM BACKGROUND OF THE INVENTION This invention relates to control systems and, more particularly, to portable dishwasher apparatus including an improved cycle timing system.

Machines for washing dishes have come into wide use. In such machines, water is usually admitted to a washing tube and drained from the tub at spaced time intervals under the control of a cycle timing system. The heart of the timing system typically consists of an electrical timer having a timer motor which drives one or more cams for opening and closing control switches affecting various functions of the cycle. While such timing control systems operate satisfactorily, they tend to be complex and expensive, often being the single most expensive sub-assembly of the apparatus.

There is a need, however, for inexpensive, portable dishwasher apparatus. In vacation homes, trailers, boats, and small apartments, there is often insufficient room for conventional'full-sized dishwashers, and persons of limited means frequently cannot afford conventional machinesuRecent studies show that inexpensive mini-sized appliances have been growing in popularity.

Although washing machines have been proposed which control the cycle without conventional timing means, the expedients employed have not significantly reduced the complexity and expense of the control system. In Jellies et al. U.S. Pat. No. 3,174,489, for example, water is introduced at a controlled rate for a time period which terminates upon the operation of an overflow system, such as a syphon, which supplies water to a continuously operating discharge pump. Means responsive to the pressure of water-flowing in the discharge pipe cocks a ratchet mechanism and advances the ratchet mechanism one step in response to decreasing pressure typifying the completion of the pump-out operation. The ratchet mechanism counts the number of pump-outs and terminates the cycle after the ratchet mechanism is operated a prescribed number of times. Generally similar devices are found in Jellies U.S. Pat. No. 3,126,024 and Seal U.S. Pat. No. 3,072,129. Some of the prior art machines employ float-responsive control systems. Thus, in Bold Pat. No. 2,715,413, a float moves along a screw causing the rotation of a conventional timing control cylinder. Cleghorn U.S. Pat. No. 2,180,035 shows a rather complex mechanism including a timer which is obstructed from operation by, among other things, a float rising or falling to a predetermined level.

V SUMMARY OF THE INVENTION It is a principal object of the present invention to provide an improved cycle timing control system.

More specifically, it is an object of the invention to provide a relatively simple, inexpensive cycle control system responsive to the position of a float and employing a spring driven ratchet mechanism of great simplicity for controlling the fill and drain sequence of apparatus such as dishwasher apparatus.

A further object is the provision of an improved cycle timing mechanism which can be manufactured inexpensively and yet provide all of the control functions necessary for the proper operation of an appliance such as an automatic dishwasher. A related object is the provision of a device of this character capable of providing a certain number of cycles, controlling certain operations at given times during the cycles, and shutting the apparatus off when operations are complete.

An additional object is the provision of an improved portable dishwasher apparatus including an inexpen sive and reliable cycle timing system.

Another object relates to the provision of improved dishwasher apparatus having simple, inexpensive sprayer means formed integrally with the bottom wall of the tub.

Briefly, the present invention contemplates a cycle timing control system in which the cycle of a dishwasher apparatus, or the like, is controlled by a floatresponsive escapement mechanism. A control shaft is coupled to a torsion spring and is biased for rotation in a first direction by manually rotating the control shaft in the opposite direction to wind the spring and set the machine for a predetermined number of cycles. A ratchet wheel is mounted on the control shaft, and a pair of pivoted detent arms are provided on opposite sides of the ratchet wheel. Each of the detent arms, which are normally biased towards the ratchet wheel. is provided with a detent abutment. These detent abutments are so located that when one is engaged with one of the teeth of the ratchet wheel, the other is spaced half-way between a pair of ratchet teeth and vice versa. In this way, rotation of the control shaft in response to the bias of the torsion spring is normally inhibited by one of the detent arms in engagement with a ratchet tooth. A float senses the level of water in the tub of the dishwasher and is mounted on a pivoted float arm which has a float arm rod extension positioned between the two detent arms. When the water in the tub reaches a predetermined high level, the float arm rod extension pushes the first detent arm away from the ratchet wheel permitting the control shaft to rotate until a ratchet tooth engages the detent abutment on the other detent arm. When, on the other hand, the level of the water in the tub falls due to the discharge of water from the tub to a predetermined low level, the float arm rod extension is pivoted in the opposite direction to push the other detent arm away from the ratchet wheel. This permits the ratchet wheel to again rotate until the detent abutment on the first arm engages a ratchet tooth. The control shaft is thus rotated a step at a time, first in response to a high water level sensed by the float, and next in response to a low water level sensed by the float.

A switch operating cam is mounted on the control shaft. When the high level sensed by the float causes release of the ratchet wheel, the cam is rotated to a position in which a high lobe engages a switch to cause a solenoid valve to assume a position in which the inflow of water to the tub is closed and the discharge of water from the tube is permitted. When the float senses the low level in the tub, the release of the ratchet wheel causes the cam to be rotated to a position in which a valley on the cam releases the switch to cause the solenoid valve to assume a second position in which the inflow to the tub is open and the discharge from the tub is closed. The cam is also provided with a shut-off lobe, larger than the rest, which engages a shut-off switch to terminate the cycle at a predetermined angular position of the control shaft.

The dishwasher apparatus of the present invention includes a sprayer constructed by providing a channel formed integrally in the bottom wall of the tub. This channel is connected to a pump to receive water therefrom and is covered by a cover plate having a plurality of spray orifices. By virtue of this arrangement, the pump and its couplings may be located directly under the bottom wall of the tub for easy access for servicing and replacement.

These and other objects, features, and advantages of the invention will become more readily apparent upon consideration of the following detailed description of a preferred embodiment with reference to the accompanying drawings.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a perspective view of dishwasher apparatus of the invention;

FIG. 2 is a partial perspective view showing the cycle control mechanism of the present invention;

FIG. 3 is a plan view of the apparatus with parts broken away;

FIG. 4 is a partial sectional view on the line 4-4 of FIG. 3;

FIG. 5 is a front elevation view of the apparatus with parts broken away;

FIG. 6 is an enlarged sectional view on the line 6-6 of FIG. 4 showing the control cam of the cycle control mechanism of the invention;

FIG. 7 is a partial sectional view along the line 7-7 of FIG. 3 showing the spray means of the dishwasher apparatus;

FIG. 8 is an exploded view of the cycle control mechanism of the invention; and

FIG. 9 is a schematic diagram of the electrical circuit of the apparatus.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT Referring to FIG. 1, it will be seen that a preferred embodiment of the invention is in the form of dishwasher apparatus 11 which is smaller than conventional size, being so proportioned that it may be conveniently placed on a kitchen counter top. The housing 12 of the dishwasher is provided with a cover 14 which may be slidably engaged with casing 12 or hinged along one edge 15 so that it may be removed or pivoted upwardly to provide access for loading and unloading dishes. The housing 12 is mounted on a base housing 16, the front wall 17 of which is provided with an opening to receive a control panel 18. The dishwasher 11 is provided with a conventional electric power cord 20. A fill hose 22 is adapted by means of a coupling 24 to be connected to a sink faucet, and a drain hose 26 is adapted to drain water from the dishwasher into the kitchen sink by gravity in counter top models. It is to be understood, however, that the dishwasher apparatus of the present invention may be adapted for under counter use. In that event, a drain pump will be provided for pumping water from the tub of the dishwasher.

With reference to FIGS. 1 and 2, it will be seen that an off-on power switch 28, a cycle control knob 30, and a neon indicating lamp 32 are provided on control panel 18. As will be apparent from FIGS. 2 and 8, control panel 18 is the front vertical wall of a U-shaped mounting member 34 having, in addition, a bottom horizontal wall 36 and a back vertical wall 38. It will be understood that mounting member is mounted in any suitable manner on base housing 16.

A principal feature of the present invention is the cycle timing control system 40. As is seen most clearly in FIGS. 2, 4, 5, 6 and 8, control system 40 includes a control shaft 42 journalled in a pair of bearing

holes

44 and 46 in back and front

vertical walls

38 and 18 respectively. Control knob 30 is mounted on an end 43 of control shaft 42 of reduced diameter and extending forwardly of control panel 18. A torsion spring 48 is mounted on control shaft 42, having one end fixed to the inside surface of wall 18 and the other end fixed to shaft 42 or to a ratchet wheel 50 mounted thereon for rotation therewith. Rotation of control knob 30 in a first (clockwise) direction will therefore serve to wind torsion spring 48 and bias control shaft 42 for rotation in the opposite (counter-clockwise) direction. As will be explained hereinafter, ratchet wheel 50 is provided with a plurality of ratchet teeth 52 which cooperate with a pair of

detent arms

54 and 56 to inhibit rotation of control shaft 42 under certain circumstances. For this prupose detent arm 54 is provided with a first abutment 58 adapted to engage with a tooth 52 of ratchet wheel 50 from one side of the ratchet wheel, and detent arm 56 is provided with a second abutment 60 adapted to engage a tooth 50 from the other side of the wheel. Each detent arm is provided with a hole 62 at its upper end by means of which it is pivoted on a sleeve 70, detent arm 56 being positioned directly behind detent arm 54 as seen in FIGS. 2 and 8. Both detent arms are normally biased to move

abutments

58 and 60 towards ratchet wheel 50. For this purpose, a coil spring 68 is connected between the lower ends 64 and 66 of

detent arms

54 and 56. It will be observed that

abutments

58 and 60 and ratchet teeth 52 are so positioned that when abutment 58 is engaged with a ratchet tooth 52, as seen in FIGS. 2 and 5, to inhibit rotation of wheel 50 and shaft 42 in the counter-clockwise direction, the other abutment 60 is positioned midway between a pair of ratchet teeth 52 as seen in FIG. 5. In like manner, when abutment 60 of detent arm 56 is engaged with a ratchet tooth 52 to inhibit counter-clockwise rotation of ratchet wheel 50 and control shaft 42, abutment 58 of detent arm 54 will be positioned midway between a pair of ratchet teeth 52. Thus, one of the

abutments

58 or 60 will normally be in engagement with a tooth 52 of ratchet wheel 50 to block rotation of control shaft 42 in the counter-clockwise direction under the influence of torsion spring 48. However, when, as will be presently explained, the abutment which is engaged with a ratchet tooth is moved outwardly from ratchet wheel 52, control shaft 42 is free to rotate in the counter-clockwise direction until the other abutment becomes engaged with a ratchet tooth 52.

These outward movements of the abutments are effected by a float 72 positioned within the tub of the dishwasher to sense the level of water therein. As will be seen in FIGS. 2, 4, 5, and 8, float 72 is mounted on the end of a float arm 74, the other end of which is apertured at 75 to receive the end of a float arm rod 76. The fit between aperture 75 and rod 76 is tight so that movement of float 72 up and down with the level of water within the tub will cause float arm 74 to rotate rod 76. For this purpose, rod 76 is journalled in a bearing 77 extending through a wall of dishwasher tub 124 and in sleeve which is mounted in an aperture 78 provided near the top of wall 38.

Detent arms

54 and 56 are pivoted on sleeve 70. Aperture 62 in detent arm 54 is provided for this purpose, and a similar aperture (not seen) is provided on detent arm 56. In order to maintain

detent arms

54 and 56 in place on sleeve 70, a pair of positioning rings 80 and 86 are affixed on sleeve 70 on opposite sides of

detent arms

56 and 54, ring 80 being spaced from detent arm 56 by a washer 82 and ring 86 being spaced from detent arm 54 by a washer 84. The front end of float arm rod 76 is provided with a downwardly extending U-bend 87 from which a float arm rod extension 88 extends parallel to rod 76 to a position between

detent arms

54 and 56 as is most clearly shown in FIG. 2. As float 72 rises with the water level in tube 124, rod 76 will rotate to bring float arm rod extension 88 into engagement with detent arm 54 pivoting detent arm 54 outwardly from ratchet wheel 50 and disengaging abutment 58 from a ratchet tooth 52. As already explained, this will permit ratchet wheel 50 to rotate counter-clockwise until a tooth 52 engages abutment 60 on detent arm 56. When, however, float 72 falls with the water level in tub 124, rod 76 will rotate in the opposite direction to bring float arm rod extension 88 into engagement with detent arm 56, pushing arm 56 outwardly from ratchet wheel 50 and disengaging abutment 60 from a ratchet tooth 52, again releasing ratchet wheel 50 for further rotation until abutment 58 engages a tooth 52. In this way, control shaft 42 is permitted to rotate through a small predetermined angle in response to the water in tub 124 reaching a predetermined high or full level and to rotate through a small predetermined angle in response to the water in tub 124 falling to a predetermined low or empty level.

This rotation of control shaft 42 is utilized to control the timing of events in the cycle of dishwasher apparatus 11. For this purpose, a control cam 90 is mounted on control shaft 42. As best seen in 6, control cam 90 is provided with a plurality of

cam lobes

92, 94, 96, 98, 100, and 102 and a plurality of

cam valleys

104, 106, 108, and 110. The cam thus provides ten control positions. Position 1 is provided by cam lobe 92 which extends radially outwardly to a greater extent than the remaining lobes to provide a first control level. As is seen in FIG. 6, when position 1 reaches the angular position shown, lobe 92 will operate a power control switch 112 by engaging switch operator 114. This will serve to open the power circuit and de-energize the apparatus as will be evident from the circuit diagram of FIG. 9.

Cam lobes

94, 96, 98, 100, and 102 extend radially outwardly to a second control level (which level is not sufficient to operate switch 112) to provide

control positions

2, 4, 6, 8, and respectively. These lobes will actuate valve switch 1 16 by engaging switch actuator 118 when the corresponding control positions are brought into coincidence with actuator 118. As will be explained more fully hereinafter, this will close valve switch 116 and will energize the winding 156 of a solenoid valve 144 causing the valve to assume a first valve position which admits water to tub 124. A third control level is provided by

valleys

104, 106, 108, and 110 which are provided between

adjacent lobes

94 and 96, 96 and 98, 98 and 100, and 100 and 102 respectively. It will be noted that control positions 3, 5, 7, and 9 correspond respectively to

valleys

104, 106, 108, and 110 and, when in alignment with switch operator 118 of valve switch 116, serve to open this switch and deenergize valve solenoid winding 156 causing valve 144 to assume a second position closing the fill port of valve 144 and opening the drain port of the valve to drain water from tub 124.

In order to prevent torsion spring 48 from being overwound, a stop sector 120 is mounted on shaft 42 adjacent to wall 38. This stop sector engages with a pin 122 projecting from wall 38 when shaft 42 is rotated to a full start position in which cam position 10 will be in engagement with switch operator 118. The shaft thus cannot be rotated beyond this start position.

Referring to FIGS. 3, 4, and 5, it will be observed that the tube 124 of the dishwasher has a bottom wall 126 provided with a depression 127 forming a well to receive float 72 when water is drained from the tub. A dish rack or basket 128 is provided with a bearing 132 by means of which the basket rotates on a spindle projecting upwardly from the center of bottom wall 126 of the tub 124. As will be presently explained, rotation of basket 128 will be caused by water sprayed thereagainst.

For this purpose, a water circulation system is provided. Water in tub 124 is received in a well 134 in bottom tub wall 126. In order to keep food debris from clogging the drain and to prevent the water circulation system from depositing food particles on the dishes, a removable filter screen 136 is provided over well 134. An opening 137 (see FIG. 4) from well 134 is coupled through a hose coupling 138 to a pump 140 which is driven by an electric motor 142. As will be evident from the schematic diagram of the electrical circuit motor 142 and pump 140 will operate continuously as long as

switches

28 and 112 remain closed. Water is drawn from well 134 by pump 140 and pumped through a coupling 145 to a sprayer 146. As is most evident from FIG. 7, sprayer 146 includes a fluid conduit provided by a channel 148 formed integrally in the bottom wall 126 of tub 124. The top of channel 148 is closed by a cover plate 150 which may be secured to bottom wall 126 by screws or the like. Cover plate 150 may be molded from a durable plastic material or may be formed of metal. In either case, it is provided with a plurality of orifices 152, some through side portions of plate 150 which are disposed at an angle to the horizontal and some through the flat central portion of plate 150. Water under pressure is thus received in channel 148 from pump 140 through coupling 145 and forced in jet streams through orifices 152'to impinge against dish rack 128 causing it to rotate and against the dishes stacked in the rack to wash them. It will be noted that pump 140 and sprayer 146 are positioned in close proximity, permitting the use of a short fluid coupling between the pump and sprayer. Since the pump and coupling are positioned just below the bottom wall 126 of the tub, the pump, coupling and sprayer are conveniently accessible for servicing. Moreover, by virtue of the compact arrangement of these components, the size of the dishwasher apparatus is substantially reduced.

As previously mentioned, water is supplied to the tub of the dishwasher through a fill hose 22 which may be connected by means of a conventional coupling to a sink faucet. The water flows through hose 22 to a threeway solenoid valve 144 (see FIG. 3). This valve has two positions. In the first position, the valve permits water to flow from fill hose 22 through a coupling 158 to well 134, admitting water to tub 124. In the second position, the port to fill hose 22 is closed, and the port to drain hose 26 is opened permitting water to drain by gravity from well 134. It will be understood that the positions of the valve 144 are controlled by solenoid 156 (see FIG. 9), the first position being assumed when solenoid 156 is energized with the closure of switch 116 and the second position when solenoid 156 is deenergized with the opening of switch 116.

The operation of the dishwasher apparatus of the invention will now be described Apparatus 11 is placed upon a countertop or other area suitable for gravity draining. Power cord 20 is plugged into a 1 volt A.C. power circuit. Fill hose 22 is connected to a hot water tap, which may be associated with a kitchen sink adjacent to the location of the apparatus, and drain hose 26 is placed in the sink so that drain water will drain from tub 124 into the sink. Door 14 is removed or opened (if the door is of the type which is hinged at 15), and dishes are loaded into basket 128 with some care as to balanced distribution. Manual switch 28 is placed in the OFF position. Control knob is then rotated clockwise to the WASl-l" position, or until stop 120 engages pin 122. This action winds torsion spring 48. Although the wound spring will now bias control shaft 42 for rotation in the counter-clockwise direction, rotation will be inhibited by the engagement of detent arm 54 with a tooth 52 of ratchet wheel 50. (Detent arm 56 will, at this time, be held away from ratchet wheel 50 by rotation of float arm rod extension 88 to the right due to the low position of float 72 in the empty tub 124). This rotation of control knob 30 also moves high lobe 92 (position 1) of cam 90 away from switch actuator 114 of switch 112 permitting switch 112 to close. Rotation of control knob 30 also places cam 90 in a position in which cam lobe 102 (position 10) engages switch actuator 118 of switch 116, closing this switch and completing the circuit to solenoid 156 so that it will be activated upon the closing of manual switch 28.

Before starting the apparatus, detergent powder is added directly to tub 124 in the proper amount. Door 14 is then replaced or closed, and the hot water tap is turned on. Manual switch 28 is placed in the ON position. Power is now applied through manual switch 28 and control switch 112 to pump motor 142, valve switch 116 and solenoid valve 156, and neon lamp 32. It will be noted from FIG. 9, that pump motor 142 will drive pump 140 continuously through the entire washing and rinsing operation as long as

switches

28 and 112 remain closed.

Since, as was mentioned above, switch 116 has been closed by cam lobe 102, solenoid 156 will now be energized, causing valve 144 to assume its first position allowing hot water to flow from fill hose 22 into base well 134 of tub 124. The water will flow into the tub at a controlled rate, depending on the pressure applied to fill hose 22 to effect the timing of the cycle. As the water slowly rises and enters the pump intake coupling 138, pump 140 becomes primed and begins to force water up to sprayer 146 causing jets of water to be sprayed through orifices 152. This will flood the dishes in basket 128 with detergent laden water. The spray jets directed through the angled orifices 152 will cause basket 128 to spin so that all of the dishes will be washed.

The rinsing water causes float 72 to rise. As float 72 rises, float arm 74 will cause float rod 76 to rotate and disengage float rod extension 88 from detent arm 56. This will permit detent arm 56 to move toward ratchet wheel 50, bringing abutment 60 midway between a pair of ratchet teeth 52. As water continues to fill tub 124, float 72 will continue to rise further rotating float rod 76 until float rod extension 88 engages detent arm 54. As the water level rises still further, float rod 76 will continue to rotate, and float rod extension 88 will push detent arm 54 off ratchet tooth 52, allowing the torsion spring 48 to rotate control shaft 42 until abutment 60 of detent arm 56 engages a ratchet tooth 52, stopping the rotation. Cam will have rotated to bring valley (position 9) in alignment with switch actuator 118. This will allow valve switch 116 to open and deenergize solenoid 156 of three-way valve 114. This will cause the solenoid valve to assume its second position. stopping thetap water from flowing into the tub and allowing the water already in the tub to drain through hose 26 into the sink by means of gravity.

Pump will continue to circulate the water in the tub until the water level becomes low enough to allow air to enter the pump through opening 137 and coupling 138, thus breaking the prime of the pump. The water will continue to drain through drain hose 26. As the water level falls, float 72 falls and causes float arm 74 to rotate float rod 76 and move float rod extension 88 away from detent arm 54, permitting detent arm 54 to move toward ratchet wheel 50 under the bias of spring 68. This will bring abutment 58 to a point midway between a pair of ratchet teeth 52. As the water level continues to fall, rod 76 will continue to rotate until float rod extension 88 engages detent arm 56 pushing it out of engagement with the engaged tooth 52 of ratchet wheel 50. This will again allow torsion spring 48 to rotate control shaft 42 until it is stopped when abutment 58 comes into engagement with a tooth 52 of ratchet wheel 50. This will put cam 90 into a position in which lobe 100 (position 8) is engaged with switch actuator 118, closing switch 116 and again energizing solenoid 156. This will cause valve 144 to assume the first position again allowing the hot tap water to enter tub 124 and closing the drainage path to drainage hose 26. This marks the beginning of the first rinse.

This fill and drain action is repeated three more times to effect a total of four cycles (one wash and three rinses) by successively unwinding the control shaft 42 until finally valve switch actuator 118 is engaged with lobe 94 (position 2) as shown in FIG. 6. At this time, also, high lobe 92 (position 1) of cam 90 is engaged with switch actuator 114 to open control switch 112 and cut off all power to the apparatus, ending the washing and rinsing cycle. With power removed, solenoid 156 is de-energized and solenoid valve 144 assumes the second position allowing the path to drain hose 26 to remain open so that all of the water in the tub can find its way to the sink. Door 14 will then be removed or opened, and the hot dishes will very quickly dry.

As will be apparent from the foregoing, cycle timing mechanism 40 consists of a mere handful of parts all of which lend themselves to mass production methods, such as injection molding, die casting, metal stamping or the like. No expensive machined parts need be employed. It is to be noted, moreover, that cycle timing mechanism 40 is designed as a compact subassembly greatly facilitating final assembly of the dishwasher and easy replacement of a defective timing mechanism as a unit. By the same token, the valve 144 and pump 140 and their associated couplings may be arranged as a compact sub-assembly mounted on the under surface of bottom wall 126 of tub 124 for ready access for servicing, if necessary, and for easy removal as a unit.

It is thus apparent that by employing the principles of the present invention it is possible to provide dishwasher apparatus which is as simple as possible so that the machine can be constructed economically without compromising its effectiveness.

The embodiment just described illustrates the invention as applied to a mechanism in its simplest form. It is to be understood that any number of cycles may be had by adding or subtracting teeth to ratchet wheel 50. Moreover, any number of control actions may be provided by adding cams and additional switches. in a complex system, a number of cams may be provided on a common control shaft each controlling cycles of different portions of the system or separate systems, all being timed by a common float rising and falling in a tank, the filling and draining of which is controlled by at least one cam. If the pressure of the supply of water is constant, the system will provide accurate timing. In anycase, the timing of the cycles will be related to the time required to fill and drain the tank. In the case of a washing apparatus, such as the embodiment disclosed herein, it will be recognized that the actions in the cycle will be related to the level of water in the tub, thus insuring that a proper amount of water has been drained from the tub between cycles.

While the embodiment disclosed employs gravity for draining water from the tub, it is to be understood that in under-counter versions of the apparatus, it will be necessary to provide an additional drain pump in the drainage line.

While the preferred embodiment of the invention has been shown and described, it will be apparent to those skilled in the art that changes can be made without departing from the principles and spirit of the invention, the scope of which is defined in the appended claims.

The invention claimed is:

l. A control system comprising:

a control shaft;

means for biasing said control shaft for rotation in a first direction;

first detent means for arresting rotation of said control shaft in said first direction;

second detent means for arresting rotation of said control shaft in said first direction, said first and second detent means being alternately effective to arrest rotation of said control shaft;

valve means for admitting a fluid to a tank when said control shaft is arrested from rotation by said first detent means; and

float means responsive to said fluid rising to a first predetermined level in said tank for releasing said first detent means to permit said control shaft to rotate in said first direction through a predetermined angle until arrested by said second detent means, said valve means draining said fluid from said tank when said control shaft is arrested from rotation by said second detent means, said float means being responsive to said fluid falling to a second predetermined level in said tank for releasing said second detent means to permit said control shaft to rotate in said first direction through a predetermined angle until arrested by said first detent means, and saidacontrol shaft being successively arrested and released by said first and second detent means to actuate said valve means to admit and drain said fluid from said tank a predetermined number of times.

2. A control system as recited in claim 1, wherein said means biasing said control shaft comprises a torsion spring and said system further comprises means for manually rotating said control shaft in a direction opposite to said first direction to wind said torsion spring.

3. A control system as recited in claim 1, wherein a ratchet wheel having a plurality of spaced teeth is mounted on said control shaft, said first detent means comprising a first pivoted detent arm biased towards said ratchet wheel and having a first abutment adapted to engage a tooth of said ratchet wheel to arrest rotation of said control shaft, and said second detent means comprising a second pivoted detent arm biased towards said ratchet wheel and having a second abutment adapted to engage a tooth of said ratchet wheel to arrest rotation of said control shaft.

4. A control system as recited in claim 3, wherein said second abutment is spaced midway between adjacent teeth of said ratchet wheel when said first abutment is engaged with a tooth of said ratchet wheel and said first abutment is spaced midway between adjacent teeth of said ratchet wheel when said second abutment is engaged with a tooth of said ratchet wheel.

5. A control system as recited in claim 4, wherein said detent arms are located on opposite sides of said ratchet wheel.

6. A control system 'as recited in claim 5, wherein said detent arms are pivoted about an axis located above said control shaft and said detent arms are biased by a spring connecting the lower ends of said detent arms below said control shaft.

7. A control system as recited in claim 6, wherein said float means comprises a float, a pivoted float arm connected to said float, and a float arm extension, said float arm extension being adapted to push said first detent arm from said ratchet wheel when said float rises to said first predetermined level and to push said second detent arm from said ratchet wheel when said float falls to second predetermined level.

8. A control system as recited in claim 7, wherein said float arm is pivoted about said axis.

9. A control system as recited in claim 3, wherein said float means comprises a float, a pivoted float arm connected to said float, and a float arm extension adapted to push said first detent arm from said ratchet wheel when said float rises to said first predetermined level and to push said second detent arm from said ratchet wheel when said float falls to said second predetermined level.

10. A control system as recited in claim 9, wherein said valve means has fill and drain positions and said system further comprises a control cam mounted on said control shaft, said control cam having a first plurality of positions having a first control level for actuating a switch, said switch closing a valve control circuit for actuating said valve means to said fill position and a second plurality of positions having a second control level for opening said switch to open said valve control circuit and to cause said valve means to assume said drain position.

11. A control system as recited in claim 10 wherein said control cam comprises a stop position having a third control level for opening a power switch at a particular angular position of said control shaft for deenergizing said system.

12. A control system as recited in claim 11, wherein said tank is the tub of dishwasher apparatus.

13. A control system as recited in claim 12, wherein said dishwasher apparatus comprises sprayer means and pump means for forcing said fluid through said sprayer means.

14. A control system as recited in claim 13, wherein said pump means operates continuously while said valve means is successively actuated to fill and drain positions.

15. A control system as recited in claim 13, wherein said sprayer means comprises a channel formed in the bottom wall of said tub and a cover plate covering said channel, said cover plate having a plurality of spray orifices.

16. A control system as recited in claim 1, wherein said valve means has fill and drain positions and said system further comprises a control cam mounted on said control shaft, said control cam having a first plurality of positions having a first control level for actuating a first switch for closing a valve control circuit for actuating said valve means to said fill position and a second plurality of positions having a second control level for opening said switch to open said valve control circuit and cause said valve means to assume said drain position.

17. A control system as recited in claim 16, wherein said control cam comprises a stop position having a third level for opening a power switch at a particular angular position of said control shaft for de-energizing said system.

18. A control system as recited in claim 17, wherein a cam lobe having a first radial extent is located at each of said first plurality of positions, a cam valley having a second radial extent smaller than said first radial extent is located at each of said second plurality of positions, and a stop cam lobe having a third radial extent greater than said first radial extent is located at said stop position.

19. A control system as recited in claim 1, wherein said tank is the tub of dishwasher apparatus.

20. A control system as recited in claim 19, wherein said dishwasher apparatus comprises sprayer means and pump means for forcing said fluid through said sprayer means.

21. A control system as recited in claim 20, wherein said pump means operates continuously while said valve means is successively actuated to fill and drain positions.

22. A dishwasher comprising a tub, valve means for admitting water to said tub, drain means for draining water from said tub, sprayer means for spraying water upon dishes to be cleaned within said tub and pump means for forcing said water through said sprayer means, said sprayer means comprising a channel formed in the bottom wall of said tub and a cover plate covering said channel, said cover plate having a plurality of spray orifices through which said water is forced.

UNITED STATES PATENT OFFICE CERTIFICATE OF CORRECTION Patent No. 3,777,989 Dated December 11, 1973 Inventor(s) Gerald M. Pacella and Richard S. Eckman It is certified that error appears in the above-identified patent and that said Letters Patent are hereby corrected as shown below:

In the Abstract, line 12, "tube" is changed to "tub".

the Abstract, line 15, "rachet" is changed'to "ratchet".

In Column 1, line 9, "tube" is changed to -tub--.

In Column 2,- line5 4, "tube" is changed to --tub--.

In. Column 5, line 1 2, "tube" is changed to --tub--.

In Column 6, line 11, "tube" is changed to "tub".

In Column7, line 63, "rinsing" is changed to "rising".

In Column 8, line 16, drain-- is inserted before "hose".

Signed and sealed this 9th day of April "19m.

( SEAL) Attest: I

EDWARD M.FLETCHER,JR. Q C. MARSHALL DANN Attesting Officer Commissioner of Patents FORM Do-1050 9 uscoMM-Dc 60376-P69 U.S. GOVERNMENT PRINTING OFFICE 1 I959 0-366-334

Claims

1. A control system comprising: a control shaft; means for biasing said control shaft for rotation in a first direction; first detent means for arresting rotation of said control shaft in said first direction; second detent means for arresting rotation of said control shaft in said first direction, said first and second detent means being alternately effective to arrest rotation of said control shaft; valve means for admitting a fluid to a tank when said control shaft is arrested from rotation by said first detent means; and float means responsive to said fluid rising to a first predetermined level in said tank for releasing said first detent means to permit said control shaft to rotate in said first direction through a predetermined angle until arrested by said second detent means, said valve means draining said fluid from said tank when said control shaft is arrested from rotation by said second detent means, said float means being responsive to said fluid falling to a second predetermined level in said tank for releasing said second detent means to permit said control shaft to rotate in said first direction through a predetermined angle until arrested by said first detent means, and said control shaft being successively arrested and released by said first and second detent means to actuate said valve means to admit and drain said fluid from said tank a predetermined number of times.

6. A control system as recited in claim 5, wherein said detent arms are pivoted about an axis located above said control shaft and said detent arms are biased by a spring connecting the lower ends of said detent arms below said control shaft.