US3114375A

US3114375A - Dishwashing machine

Info

Publication number: US3114375A
Application number: US167496A
Authority: US
Inventors: Frederick W Blanchard
Original assignee: Individual
Current assignee: Individual
Priority date: 1962-01-22
Filing date: 1962-01-22
Publication date: 1963-12-17
Anticipated expiration: 1980-12-17
Also published as: GB974631A; GB974632A; DE1428341A1

Description

Dec. 17, 1963 F. w. BLANCHARD 3,114,375

DISK-[WASHING MACHINE Filed Jan. 22, 1962 5 Sheets-Sheet 1 Dec. 17, 1963 F. w. BLANCHARD DISHWASHING MACHINE 3 Sheets-Sheet 2 Filed Jan. 22, 1962 Dec. 17, 1963 F. w. BLANCHARD 3,114,375

DISHWASHING MACHINE Filed Jan. 22, 1962 3 Sheets-Sheet 3 United States Patent ()fi ice 3,114,375 Patented Dec. 17, 1963 3,114,375 DESHWASHING MACHINE Frederick W. Blanchard, 4095 Broadway, Lachine, Quebec, Canada Filed Jan. 22, 1962, Ser. No. 167,496 7 (Ilaims. (Cl. 134-138) This invention relates to a dishwashing machine, and more particularly to a dishwashing machine of what may be called the motor-less type, for household use in washing plates, cups, tumblers, saucers, and flatware.

An object of the invention is the provision of a gen erally improved and more satisfactory dishwashing machine of this kind.

Another object is the provision or" a machine so designed as to minimize the escape of water at the cover of the machine, even though the lid or cover of the machine is not clamped or tightly sealed.

Another object of the invention is the provision, in a water operated machine without an electric motor, of improved water spray means for rotating the load of articles to be cleaned at an approximately constant rate of speed, notwithstanding substantial variations in the amount of load in the carrying basket.

A further object is the provision of improved spray means so designed and constructed as to enable easy adjustment of the rotary speed of the machine, during the process of manufacture assembly, to produce the desired rotary speed.

These and other desirable objects may be attained in the manner disclosed as an illustrative embodiment of the invention in the following description and in the accompanying drawings forming a part hereof, in which:

FIG. 1 is a vertical section taken approximately diametrically through the entire machine and a fragment of a kitchen counter top or shelf in which it may be installed;

FIG. 2 is a fragmentary plan showing approximately one-half of the load-carrying basket which rotates within the machine, and showing also the spray tube and the spray orifices therein; and

FIG. 3 is a somewhat schematic fragmentary view, partly in elevation and partly in vertical section, illustrating the angles of the various sprays and their relation to the load-carrying basket.

.aohines of the motorless type are well known in the rt, a typical example being the machine shown in the resent applicants United States Patent 2,762,558, granted 'ebruary 22, 1955. The present invention may be re -.rded as an improvement over the construction shown 11 applicants prior patent above mentioned.

Experience with machines of this kind has demonstrated two difficulties, both of which are overcome by the present construction as herein disclosed. The first difficulty is the matter of escape of water onto the counter top. This could be overcome by providing an impervious cover or lid in tightly sealed relation to the body of the machine, but a tight sealing arrangement requires various fastening means, sealing rings, and the like, which not only require some positive action by the operator to lock or unlock or both, but are susceptible to damage by rough handling of the lid. Further, various jurisdictions have plumbing codes or building codes relating to sealed essels diilicult to comply with in a machine for national distribution. For these reasons it is desirable, as a practical matter, that the cover be allowed to remain loose or unclamped, but with prior constructions or loose covers on dishwashing machines, the-re has usually been considerable escape of water through the cover or onto the counter top. Such escape is minimized or completely eliminated by the present construction, as further described below, even though the cover of the machine is held in place only by gravity.

The second difliculty which has frequently been encountered in the past, in machines of this general type, is the matter of maintaining the desired speed of rotation of the basket containing the load of articles to be washed. If the speed is too slow the basket tends to stall if the dishes and the like are not uniformly arranged. lf the'speed of rotation is too fast there may be ineflicient washing. Accordingly, there is an optimum speed range at which the machine operates most efliciently. For example, in a machine having a basket of approximately 17 inches in diameter it has been found that the optimum range is from 40 to 60 rpm. and preferably 50 r.p.m. The main variable causing differences in rotational speed in prior dishwashers of this same general type, is the variation in the size and distribution or" the load of tableware to be washed. The distribution of the load usually has a greater effect upon the speed of rotation, than the total weight of the load. The water jet arrangement of the present invention largely overcomes speed variations caused by differences in load, as well as those caused by manufacturing variations.

Referring now to FIG. 1 of the drawings, the machine in general comprises a main casing or tub having side walls ll. of approximately cylindrical form, and a bottom 13 which is approximately list but which slopes slightly toward the center where it is connected to a drain or discharge conduit 15, the top of which is covered by a screen 17. Near the top or" the side wall ill, the wall is bent radially outwardly to form a horizontal flange at 19, then upwardly approximately cylindrically as at 21, and terminates in another outwardly extending radial flange 23 which may rest upon a counter top, shelf, or other structure 25' in which or on which it is desired to mount the dishwashing machine. In a typical installation intended for domestic use by a small family, the casing or tub 311 may have a diameter of about 18 or 19 inches, and a depth from the top flange 23 to the bottom 13 of about 13 inches, but these dimensions are given merely by way of example rather than by way of limitation.

When the machine is not being loaded or unloaded, the open top of the tub 11. is normally closed by a circular cover 31 in the form of a sheet of suitable metal (preferably aluminum) having a central depression 33 at the center of which there is a knob or handle 35 for convenient grasping to lift the cover. At its outer edge, the cover has a down turned cylindrical portion 37 which normally rests on the outwardly turned horizontal flange 19' of the tub ill, in the position shown in FIG. 1. The outer diameter of the cylindrical portion 37 is sufficiently smaller than the inner diameter of cylindrical portion 21 of the tub, so that there is a slight gap 38 all the way around the cover, between the members 21 and 37, when the cover is in normal closed position. This gap 38 is preferably about /8 to of an inch, in a radial direction, and about one inch in height, since the depth of the cylindrical portion 37 on the cover is preferably about one inch, and the height of the cylindrical portion 21 between the horizontal flanges 19 and Z3 is likewise about one inch.

A variant of the construction just described is to extend the side wall 11 to the full height of the machine, without a flange like present flange =19, and terminating in a horizontal flange like the present flange 23. In this case, an internal member such as a light channel or angle bar (not shown) could be attached to and run circumferentially around the inside of the side wall 11, at the elevation of the present flange 19, to form a support for the bottom edge of the portion 37 of the cover 31. One advantage of such alternative construction is that internal diameter of the main portion 11 of the machine can be thereby enlarged slightly without any enlargement in the size of the cover 31, by providing a diameter horizontally through side wall 11 of the same size as the diameter horizontally through the cylindrical portion 2 1.

The cover 31 is preferably quite light, as owing to the construction provided herein there is no appreciable thrust tending to lift the cover 31 upwardly when the machine is in operation. As already mentioned, such feature is of considerable advantage.

It may he helpful to discuss briefly the pressure which tends to build up in a dishwashing machine of the present construction. As will be described below, jets of hot water are used to Wash the dishes and such hot Water and accompanying steam create vapor pressure inside the machine. In the case of a dishwashing machine permanently installed and connected to the existing water supply and sewage system, the vapor pressure cannot escape freely through the drain 15 because of the back pressure caused by the usual trap in the sewage system. By contrast a portable machine having a drain tube or the like would not have the back pressure mentioned. Water poured down the drain easily overcomes the trap back pressure, but such back pressure is nevertheless present and is quite sulficient to lift a cover of ordinary size and weight and permit water to escape when the machine is in operation.

According to the present invention, this condition is overcome, and the escape of water is entirely eliminated by fitting the cover to the tub in the manner already described and by providing the downturned cylindrical portion 37 of the cover with a series of circumferentially spaced small holes 39 located at about one-quarter of the way up from the bottom edge of the flange 37 to the top thereof. In one satisfactory form of the machine the holes 3? are of an inch up from the bottom edge of the cover flange. The number and spacing of the holes 39 are subject to variation, but for a machine having the typical dimensions above given, it is found that excellent results are obtained when the holes 39 are about of an inch in diameter, and when about 60' of such holes are used, equally spaced around the circumference of the circular flange 37 of the cover.

Preferably the under face of the cover 31 is provided with a layer 41 of acoustical insulation material, such for example as a layer of synthetic foam sheeting about A of an inch thick. This serves the additional purpose of helping to deaden the noise of operation of the machine.

When the machine is in use, vapor pressure created inside the machine is vented through the holes 39' into the gap between members 3 7 and 21 and thence to the atmosphere. In spite of the fact that inside the machine there are several jets of hot water (to be described below) and a considerable amount of steam, the venting just described takes place without water ordinarily escaping, and with no tendency to lift the cover 31. The exact function is not presently known, but it has been found that the construction just described is very effective in keeping the pressure inside the machine at substantially zero without allowing water to escape.

Continuin with the description of other features of the machine, and still referring to FIG. 1 of the drawings, centrally located at the bottom of the tub is a casting 51 which bridges over the central drain opening in a direction at right angles to the plane of the paper in FIG. 1, and which is firmly secured at its two ends to the bottom wall 13 of the tub. Fixed to and supported by this casting 51 is the vertical pivot 53 having at its upper end a hole for receiving and retaining the hardened steel ball 55 which serves as a bearing for the lower end of a hardened steel thrust bearing 57, the upper end of which is enlarged at 59 and brazed, welded, or otherwise firmly secured to the upper end of a tube 61 'which extends down the length of the pivot rod 53 almost to the bottom thereof, and which is slightly spaced laterally from the rod. Bearing sleeves 63 and 65 of low friction material such as oil impregnated bushings, located near the top and bottom, respectively, of the tube 61, serve to bear lightly on the pivot 53 and to keep the remainder of the tube 61 spaced from the pivot rod.

Welded, soldered, brazed, or otherwise suitably secured around the bottom end of the tube 61, is a collar 67 having outwardly turned bottom flange 69, to which are welded or otherwise secured the inner ends of the approximately radial rods 71, the outer ends of which are bent upwardly as at '73 and secured at their upper ends to a circular ring 75. These rods 71 have upstanding plate separator fingers 77 secured to them, the spaces between the separators forming slots into which various sizes of plates to be washed may be placed.

Any desired number of these arms '71 may be used. In a typical machine having the dimensions given above by way of example, there are eight such rods extending radially with respect to the central tube 61, and angularly spaced equally at 45 degrees from each other. Between certain of these main radial structures '71 there may be other supplemental radial structures such as the rods 81, the outer upstanding ends 83 of which are secured to the same circular ring '75 above mentioned, and the other ends of which are bent into an inverted U-shaped structure 35' as well seen in FIG. 1, to serve as supports for holding tumblers or similar hollow articles in inverted position. The radial inner ends of the structure 51 may be welded or otherwise fastened to a ring 87 concentric with the tube 61, this ring also being fastened to and supported by the main radial members 71.

A cup shaped holder 91 for the flatware to be washed (knives, forks, spoons, etc.) may surround the tube 61 concentrically therewith, and may rest on and be supported by the radial members '71. The bottom of this flatware holder is preferably in the form of a screen or other foraminous structure 93, re-enforced by

rings

95 and 97. The side walls 'of the cup 91 may be either solid or foraminous, as desired.

Removably supported near the top of the tube 61 is a wire frame structure for holding cups or mugs in inverted washing position. This cup holder preferably comprises a central hub in the form of a tubular sleeve 161 loosely surrounding the upper portion of the tube 61 and supported at the desired elevation on the tube in any suitable manner. For example, the lower edge of the sleeve 161 may simply rest on a lug or projection fixed to the outside of the tube 61 to project slightly therefrom. Altcrnativcly, the upper end of the sleeve 181 may have fixed to it a diametrical pin 103 which rests loosely in a notch 165 formed diametrically in the top of the member Various wires 1:17, 109, and 111, bent to the shapes shown and fastened to each other and to the hub sleeve 1511, serve as holders for supporting cups or mugs in inverted position. The entire cup holder may be lifted upwardly off of the tube 61, for ease in loading and unloading the plates, tumblers and flatware in the space beneath. When the cup holder is again to be used, it is simply slipped over the top of the tube 61, and it settles down to the intended elevation.

All of the structural parts 57 to 111, inclusive, may collectively be called the load basket or load carrier, and all of the tableware such as plates, tumblers, cups, latware, etc, placed in or on the load carrier may collcctively be called the load.

Near the bottom of the tub 11, at an elevation slightly below the bottom of the load basket, is a spray tube 1"1 extending approximately radially into the machine, the inner end of the tube being held at or close to the center of the machine by a suitable socket on the casting 51. The inner end of the tube is closed as by means of a plug 123. The tube passes approximately radially outwardly through theside wall 11 of the casing, through a water tight collar ndicated in general at 125, and the outer end or the tube is connected in any suitable way to any suitable supply of hot water. The connection to the water supply may be through a known form of timing cycle mechanism, or through a manually controlled valve, whereby the householder turns on the water supply to the dishwashing machine whenever desired, and leaves it on for such length of time as experience indicates is necessary for the proper washing of the load.

It is desirable that the machine operate at fixed pressure, and in a machine of the size indicated, such pressure would be about 40 pounds per square inch. This may be accomplished by providing a supply line having a pressure higher than the working pressure, say 60 p.s.i., and making use of a needle valve or other pressure reducing valve in the supply line to adjust to the working pressure.

The above-mentioned spray tube 121 has orifices for issuance of sprays or jets of water, both for the purpose if impinging upon and cleaning the various articles of the load, and for the purpose of rotating the basket or load carrier so that all articles of the load are successively and repeatedly brought under the action of the jets or sprays. The particular location and arrangement of the jets or sprays constitute important features of the present invention.

Referring now to FIGS. 2 and 3 of the drawings, there are at least two and preferably three different kinds of jets or sprays. First there is the main series of jets, which may be called the propulsion jets, which do the main washing of the load and which also serve as the main propulsion force for rotating the basket. Second, there are the reaction jets or reverse jets which serve as brakes to prevent excessive speed of rotation of the basket due to irregularities in loading, these jets also serving to help wash the bottom faces or under sides of the plates in the load. Third, preferably there is also an additive propulsion jet serving the double purpose of insuring rotation of the basket even under such conditions of partial load that it would not otherwise rotate, and of enabling an adjustment or trimming of propulsive power to compensate for variations in manufacture, as in the case of orifices not accurately placed or having rough or burred edges, resulting in unpredictable positioning of the jets of water.

The main propulsion jets are formed by a series of holes 131 drilled or otherwise formed radially in that part of the tube 121 which is within the casing or tub, at various predetermined intervals along the length of the tube. All of these jet orifices 131 are preferably in or very close to a plane extending axially along the center of the tube 121 and tilted upwardly and forwardly at an angle of preferably 18 degrees to the vertical, plus or minus a permissible variation of one degree. The jets issuing from these orifices 131 are shown schematically at 132 in FIG. 3. For a dishwashing machine having the typical dimensions above given by way of example, there are preferably twelve of these propulsion jet orifices 131, not spaced evenly but spaced somewhat closer together near the outside of the machine, and progressively farther apart closer to the center of the machine in approximate inverse proportion to the distance from the center of rotation. Thus if the jets are numbered in sequence from the outer end inwardly toward the center, jets 2 and 3 are a little farther apart than the spacing between jets 1 and 2, 3 and S are still farther apart, 4 and 5 are spaced a little farther, 5 and 6 are spaced still farther, and 6 and 7 have a still greater spacing between them. Jets 7 and 8 are spaced still farther apart than the spacing between 6 and 7. The

spacing between jets 8 and 11 is greater than the spacing between '7 and 8, but in between jets 8 and 11 are the two extra jets 9 and 16, at lesser spacing, ecause it is found that at this point it is desirable to have some additional water supply for additional assurance of satisfactory washing of cutlery in the holder hi, and of the tumblers supported on the tumbler holders $5, and the cups or mugs supported higher up on the cup supporting 6 structure. The final or number 12 jet, closest to the center, is located at a point approximately midway, in a radial direction, between the tube 61 and the wall 91 of the flatware holder, so as to throw a jet obliquely upwardly through the screen bottom of the flatware holder, to assist in washing the flatware therein.

The reaction jet or reverse jet orifices are shown at 133. In number they are preferably about one-third of the number of main or propulsion jets. Thus if the machine has 12 propulsion jets, as in the specific example above, there are preferably four of the reaction jet orifices 133. These orifices extend radially through the wall of the tube 121, and lie in or close to a plane extending along the axis of the tube 121 and tilted 60 degrees rearwardly from the plane of the propulsion jets 1312, so that if the latter are tilted at the preferred angle of 18 degrees forwardly from a vertical plane, the reaction jets (schematically shown at 134 in FIG. 3) will be in a plane tilted 42 degrees rearwardly from the same vertical plane.

The spacing of the reaction jet orifices 133 along the tube 121 is similar to the spacing of the main propulsion jets, in that the jets are spaced increasingly farther apart from the outer edge toward the center. The first of the reaction jets (numbering from the outer one toward "the center) is approximately opposite the third of the propulsion jets, as plainly seen in FIG. 2, and in a position to impinge upon plates placed in the first or second slot (counting from the outside inwardly toward the center) of the plate separator structure. The second reaction jet is approximately opposite a point midway between jets 5 and 6 of the propulsion series, in position to engage plates in the third slot of the plate separator structure. The third reaction jet is spaced a little further inwardly beyond the seventh of the propulsion jets, in position to impinge approximately on plates in the innermost one of the slots of the plate separator structure. The last or fourth one of the reaction jets is opposite a point between jets 1i and 11 of the propulsion series, as seen in HS. 2. This jet will react against tumblers on the tumbler supports 35 as they swing around toward the spray tube 121.

The third type of jet, the additive propulsion jet, is not formed merely by a'radial hole in the tube 121, as Was the case with the other jets, but is preferably formed by a short tube 135 having its inner end fastened tightly in an opening in the tube 121, the jet tube 135 extending outwardly a distance of about A1 of an inch to A1 of an inch radially from the periphery of the tube 121. This additive jet tube 135 is made of metal which is reasonably stiff to retain its shape in use, but which is nevertheless slightly bendable by exertion of reasonable force. Brass or bronze tubing of about inch external diameter is suitable for this purpose, and the outer end of the tube preferably has a portion of reduced internal diameter as shown in FIG. 3, to produce a nozzle elfect, providing a jet or stream in a definite predetermined direction such as shown schematically at 13%.

This additive jet tube 135 is initially manufactured and assembled at a forward angle or tilt of 60 degrees to the vertical (plus or minus one degree), and is located about two-thirds of the way out from the center of the machine toward the outer edge of the load basket. Preferably the jet tube 135 is so placed and directed that its jet impinges on a part of the basket structure, such as on the shaded areas M1 (FIG. 3) of the arms '71, '73 and the separators 77. Thus it provides a rotational force or thrust even when there is little or no load in the basket to be impinged upon by the main propulsion jets 132.

Although jet tube has been shown and described, it should be understood that alternative construction is possible. A simple hole drilled at the angle and position indicated for tube 135 will be approximately correct, considering the fairly large permissible range of rotational speed of the basket, and by carefully selecting the size of such drilled hole by manufacturing experience, results very close to that achieved by jet tube 135 can be attained.

Also, instead of one drilled hole as an alternative to jet tube 135, there may be two or more drilled holes spaced relatively close together in the same plane relative to the axis of spray tube 21.

As already indicated above during the general discussion, it is desirable that the load basket in a machine of this type rotate at an approximately constant speed notwithstanding variations in the character and distribution of the load of articles to be washed. In practice, in a machine having the dimensions given above by Way of example, it is found that best results are obtained when the basket rotates at from 40 to 60 revolutions per minute, as already mentioned, and the present construction efliciently produces this rotation.

A factor to consider is that in a machine of this type, better and more eificient washing is obtained if the propulsion jets are nearly vertical, since this gives better assurance of the jets reaching all parts of the surface of each plate or dish, since the plates themselves are nearly vertical in the notches of the plate separator structure '77 and are arranged approximately tangent to successive concentric circles around the center post 53. Typical sizes of plates are indicated schematically by the broken circles 151 in FIG. 3. The nearly vertical direction of the jets also gives greater assurance that jets will reach high enough to cleanse the cups in the

cup holder structure

107, 109, 111 and to reach and cleanse the top edges of the largest plates 151. At the same time, the number of jets should be kept down to the minimum required for adequate cleansing, because every additional jet means a greater use of hot water, and added expense both to procure the water and to heat it.

If one is trying to minimize the number of propulsion jets for the sake of economy in use of hot water, then these jets must be placed at a considerable angle to the vertical, in order to assure sufiicient rotary propulsive force to turn the basket under the most unfavorable load conditions and the most unfavorable water pressure con- '(lJilOIlS likely to be encountered in practice. This produces a loss in efiiciency because the jets are not so nearly vertical as would be desirable. But the present invention overcomes this, because the additive jet 136 can be relied upon for a good deal of the propulsive or rotary force needed, so that the main series of jets 132 from the orifices 131 can be swung upward to a more nearly vertical position with the attendant advantages and eificiencies of such nearly vertical position. As already indicated, the main jets are preferably at an angle of only 18 degrees to the vertical, which is a considerably lesser angle than with comparable structures in the prior art.

Moreover, the making of the additive jet orifice 135 in the form of a bendable tube is an important feature because the tube can be bent by the person testing the machine during manufacture, to vary the position of impact of the additive jet to a slight extent, to allow for manufacturing variations. Moreover, in the case of extra low water pressure at various locations, a plumber can also make use of the additive jet 136 to cause the machine to operate. Otherwise, there would be danger that the machine would not operate at all if the available pressure is far below the working pressure. This adjustment would be made by trial, the plumber observing the rate of rotation of the basket and then taking a pair of pliers and bending the tube 135 a little one way or another, to make the jet or stream 136 issuing therefrom impinge more or less on one part of another of the basket, until the desired speed of rotation of the basket is attained, under normal water pressure conditions at the location where the machine is installed. If normal water pressure condrtrons at that location are later altered (as for example by installation of a new pumping station, or new water mains to serve an area inadequately served previously) then the plumber can again bend the tube 135 as may be necessary to adjust the speed of rotation, the tube 135 thus acting as a trimmer means for close adjustment.

The additive jet 136, being set to impinge on the structure of the basket at a substantial angle to the vertical, assures rotation of the basket even under adverse load conditions of light load or no load. Under full load conditions, where there are more articles to be impinged by the main propulsion jets 132, there would be a greater tendency of the basket to speed up and go too fast, but this is counterbalanced and overcome to a very great degree by the reaction jets 134 issuing from the orifices 133, which react against the same articles in the load, in a reverse direction, tending to slow them up as well as impinging upon and washing other surfaces not reached by the main jets 132. The more articles there are in the load to be impinged by the main jets to produce greater propulsive force tending to turn the basket, the more articles there will be to be impinged by the reaction jets 134. In actual practice, it is found that this arrangement is remarkably effective in keeping the basket at an approximately constant speed of rotation, under all load condiions from just a few articles to be washed, up to a full load with all spaces filled. As already indicated, the reaction jets are fewer in number than the forward propulsion jets, but they are spaced so as to impinge on definite predetermined articles of tableware.

This combination of forward propulsion jets at only a slight angle to the vertical, along with reaction jets in a reverse direction at a greater angle to the vertical, and with an additive propulsion jet at a still greater angle to the vertical in a forward direction, is found to give excellent results also in keeping a constant speed of rotation during any water pressure variations which may o cur from moment to moment during the day. In the some way that the reaction jets tend to slow down any excessive speed that might be caused by impingement of the propulsion jets on a greater number of articles than would be the case with only a partial load, so also the reaction jets tend to slow down any increase in the speed of the basket that may be caused by an increase in the water pressure. If the water pressure increases, the force of the forward propulsion jets increases but the force of the rearward reaction jets also increases, and vice versa if the pressure drops.

The use of reverse jets along with forward jets has been suggested in the prior art, but in all of the prior suggestions so far as now known, the jets have been arranged in a rather haphazard manner, with no attempt to have the jets carefully thought out and arranged to perform specific purposes or functions as is done in the present construction. The construction as herein disclosed results in a superior machine of high efiioiency.

The orifices 131 of the propulsion jets 132 and the orifices 133 of the reverse jets 134 are preferably all of the same size, so that all of these jets are of the same power or force, considering them merely as jets per se, without regard to their spacing and direction. Of course the force that any jet exerts on the basket, tending to rotate it, will vary (1) approximately in proportion to the sine of the angle of tilt of the jet relative to the vertical, and also (2) approximately in proportion to the radial distance of the jet outwardly from the axis of rotation of the basket, and (3) will be further influenced by the varying angle at which the jet strikes a part of the basket or a surface of a plate or other article of tableware in the basket at any given moment during the rotary travel of the basket.

As for the first of the factors above mentioned, the sine of '18 degrees (the preferred forward tilt angle of the propulsion jets 132) is 0309, while the sine of 42 degrees (the preferred rearward tilt angle of the reverse jets) is 0.669, more than twice as great. However, it must be remembered that there are more than twice as many (preferably three times as many) propulsion jets as there are reverse jets. Also the propulsion jets are more heavily concentrated at greater radial distances from the axis of rotation (second factor above mentioned), the

net result of the first and second factors being that the jets give greater forward propulsive force than the rearward or reverse thrust force. The third factor is unpredictable, varying from load to load depending upon the exact placing of the plates and other articles. The final net result of all the factors, as ascertained by extensive testing, is that the preferred jet arrangement herein disclosed gives excellent results and very satisfactory, efiicient, and economical washing of the tableware.

It is seen from the foregoing disclosure that the above mentioned objects of the invention are well fulfilled. It is to be understood that the foregoing disclosure is given by way of illustrative example only, rather than by way of limitation, and that without departing from the invention, the details may be varied within the scope of the appended claims.

What is claimed is:

l. A dishwashing machine comprising a housing, a tableware-carrying basket mounted within said housing for rotation about a vertical axis, a Water spray tube extending approximately radially within said housing below the bottom of said basket, a first series of jet orifices at spaced intervals along said tube to provide a series of main propulsion water jets issuing from said spray tube and directed obliquely upwardly and forwardly substantimly in a common plane tilted forwardly at a relatively small angle to the vertical, a second series of jet orifices at spaced intervals along said tube to provide a series of reaction water jets issuing from said spray tube and direoted obliquely upwardly and rearwardly substantially in a common plane tilted rearwardly at a much greater angle to the vertical than the forward tilt of the main propulsion jets, the jet orifices of the second series being substantially less in number than those of the first series, and additional orifice means on said spray tube to provide an additive propulsion jet directed obliquely upwardly and forwardly at an angle to the vertical substantially greater than the angle of tilt of either of the first two series of jets, said additive propulsion jet being arranged to impinge upon successive portions of said basket to provide sufiicient propulsive force to insure rotation of said 10 basket under such load conditions that impingement of said main propulsion jets on the load of tableware in said basket would not by itself rotate said basket at a desired speed.

2. A construction as defined tlfl claim 1, wherein the angle between the common plane of the jets of the first series and the common plane of the jets of the second series is substantially degrees.

3. A construction as defined in claim 1, wherein the angle between the common plane of the jets of the first series and the direction of the additive propulsion jet is substantially 42 degrees.

4. A construction as defined in claim 1, wherein said additional orifice means includes a branch tube leading laterally from said approximately radial spray tube and being of bendable material so that it may be bent to produce exact adjustment of the direction of the jet issuing therefrom.

5. A construction as defined in claim 1, wherein there are more than twice as many jets in the first series as in the second series.

6. A construction as defined in claim 1, wherein there are approximately three times as many jets in the first series as in the second series.

7. A construction as defined in claim 1, wherein at least some or the jets of the first series and of the second series are spaced at progressively increasing distance from each other, inwardly from the outermost jet of each series toward the axis of rotation of the basket.

References Cited in the file of this patent UNITED STATES PATENTS 1,574,452 South Feb. 23, 1926 1,620,671 Merseles Mar. 15, 1927 1,633,803 B-allin June 28, 1927 2,124,052 Clough July 19, 1938 2,426,291 Abrams Aug. 26, 1947 2,642,369 Hunter June 16, 1953 2,702,558 Blanchard Feb. 22, 1955 3,060,946 Lantz Oct. 30, 1962

Claims

1. A DISHWASHING MACHINE COMPRISING A HOUSING, A TABLEWARE-CARRYING BASKET MOUNTED WITHIN SAID HOUSING FOR ROTATION ABOUT A VERTICAL AXIS, A WATER SPRAY TUBE EXTENDING APPROXIMATELY RADIALLY WITHIN SAID HOUSING BELOW THE BOTTOM OF SAID BASKET, A FIRST SERIES OF JET ORIFICES AT SPACED INTERVALS ALONG SAID TUBE TO PROVIDE A SERIES OF MAIN PROPULSION WATER JETS ISSUING FROM SAID SPRAY TUBE AND DIRECTED OBLIQUELY UPWARDLY AND FORWARDLY SUBSTANTIALLY IN A COMMON PLANE TILTED FORWARDLY AT A RELATIVELY SMALL ANGLE TO THE VERTICAL, A SECOND SERIES OF JET ORIFICES AT SPACED INTERVALS ALONG SAID TUBE TO PROVIDE A SERIES OF REACTION WATER JETS ISSUING FROM SAID SPRAY TUBE AND DIRECTED OBLIQUELY UPWARDLY AND REARWARDLY SUBSTANTIALLY IN A COMMON PLANE TILTED REARWARDLY AT A MUCH GREATER ANGLE TO THE VERTICAL THAN THE FORWARD TILT OF THE MAIN PROPULSION JETS, THE JET ORIFICES OF THE SECOND SERIES BEING SUBSTANTIALLY LESS IN NUMBER THAN THOSE OF THE FIRST SERIES, AND ADDITIONAL ORIFICE MEANS ON SAID SPRAY TUBE TO PROVIDE AN ADDITIVE PROPULSION JET DIRECTED OBLIQUELY UPWARDLY AND FORWARDLY AT AN ANGLE TO THE VERTICAL SUBSTANTIALLY GREATER THAN THE ANGLE OF TILT OF EITHER OF THE FIRST TWO SERIES OF JETS, SAID ADDITIVE PROPULSION JET BEING ARRANGED TO IMPINGE UPON SUCCESSIVE PORTIONS OF SAID BASKET TO PROVIDE SUFFICIENT PROPULSIVE FORCE TO INSURE ROTATION OF SAID BASKET UNDER SUCH LOAD CONDITIONS THAT IMPINGEMENT OF SAID MAIN PROPULSION JETS ON THE LOAD OF TABLEWARE IN SAID BASKET WOULD NOT BY ITSELF ROTATE SAID BASKET AT A DESIRED SPEED.