US3003327A - Ice making machine - Google Patents

Description

06L 1961 J. D. cox ETAI. 3,003,327

ICE: MAKING MACHINE Filed Aug. 25. 1958 8 Sheets-Sheet 1 INVENTORS. JOSEPH Q COX DANSBV A. COUNCIL A TTORNEV Oct. 10, 1961 J. D. ccx ETAI.

ICE MAKING MACHINE 8 Sheets-Sheet 2 Filed Aug. 25, 1958 INVENTORS. JOSE/#1 D COX DANSBY A. COUNCIL BY W moan ATTORNEY 1951 J. D. cox ETA]. 3,003,327

ICE MAKING MACHINE Filed Aug. 25, 1958 8 Sheets-Sheet 3 INVENTORS. Q JOSEPH L: cox DANSBY A, COUNCIL am L mww A7TORNEY Oct. 10, 1961 J. D. cox ETA]. 3, ,3 7

ICE MAKING MACHINE Filed Aug. 25, 1958 8 Sheets-Sheet 4 INVENTORS. JOSEPH l2 COX DANSBY A. COUNC/L ATTORNEY Oct. 10, 1961 J. D. cox ETA]. 3,

ICE MAKING MACHINE Filed Aug. 25, 1958 8 Sheets-$heet 5 INVENTORS.

/0/ I00 JOSEPH D COX DANSBY A. COUNCIL A TTORNEV 1951 J. D. cox ETAI. 3,003,327

1cm MAKING mcum:

Filed Aug. 25, 1958 8 Sheets-Sheet 6 INVENTORS. JOSEPH D. COX DANSB) ,4v COUNC/L BY QZMW. A4.

A TTORNEV Oct. 1 0, 1961 J. D. cox EIAL 3,003,327

ICE MAKING MACHINE Filed Aug. 25, 1958 8 Sheets-Sheet 7 11 W l F INVENTORS. JOSEPH D. COX DANSBV A. COUNCIL ATTORNEY Oct.,l0, 1961 J. D. cox ETAL 3,003,327

ICE MAKING MACHINE Filed Aug. 25, 1958 8 Sheets-Sheet 8 INVENTORS.

JOSEPH D COX DANSBY A. COUNC/L 42am. mag

A TTORNEV United States Patent 3,003,327 ICE MAKING MACHINE Joseph Dennis Cox and Dansby Anderson Council, Fort Smith, Ark; said Cox assignor to said Council Filed Aug. 25, 1958, Ser. No. 757,648 8 Claims. (Cl. 62-132) This invention relates to a refrigerating apparatus and more particularly to an improved automatic ice making machine adapted to produce clear, sanitary, chipped or cubed ice, and to store the same.

The primary object of the invention is to provide an automatic ice making machine in which the thickness of the ice produced in each cycle is maintained constant.

Another object of the invention is to provide an automatic ice making machine in which the duration of the freezing to produce uniformly thick ice is controlled by the Weight of the ice, which upon reaching a predetermined value causes movement of the evaporator, upon which the ice is formed, such movement causing freezing to end.

A further object of the invention is to provide an automatic ice making machine in which the ice is formed on one or more inclined evaporator plates, only one of which is mounted for movement about a pivot, such movement, upon production of the predetermined weight of ice, controlling and stopping the freezing phase in all of the evaporator plates.

A still further object of the invention is to provide an improved means for harvesting the ice in slab form, chipping it or crushing it for storage in a cabinet compartment of the ice forming machine.

Yet another object of the invention is to proivde an ice making machine capable of producing ice cubes or chips of ice of uniform size and further capable of variation of the size of such chips.

A still further object of the invention is to provide in an ice forming machine, an improved ice crusher capable of breaking a slab of formed ice into chips convenient for use in glasses containing drinks to be chilled, and such crusher having removable and replaceable revolving crusher teeth which interact with rfixed jaws to yield ice chips of uniform and predetermined size.

Still another object of the invention is to provide in an automatic ice making machine a motor driven crusher which is responsive to an increase in pressure in the refrigerant outlet conduit of an evaporator, due to presence of hot fluid, to start the crusher, and responsive to lowering of pressure in such conduit, because of absence of the ice thawing hot fluid, to stop the crusher..

Yet another object of the invention is to provide an ice making machine of simple construction which will enable and insure efficient operation and trouble-free harvesting of ice chips of uniform size;

The novel features that are considered characteristic of the invention are set forth with'particularity in the appended claims. The invention itself, however, both as to its organization and its method of operation together with additional objects and advantages thereof, will best be understood from the following description of specific embodiments when read in connection with the accompanying drawings, wherein like reference characters indicate like parts throughout the several figures and in which:

FIGURE 1 is a front elevation of a preferred form of the ice making machine of this invention with portions broken away to reveal components within the machine;

FIG. 2 is an enlarged, fragmentary, elevational view of the evaporator plate and crusher within the machine with the evaporator in its normal freezing position;

FIG. 3 is a vertical sectional view of the parts in 3,003,327 Patented Oct. 10, 1961 2 but showing the evaporator plate after it has moved to harvesting position;

FIG. 4 is a side elevation of the crusher as viewed from within the cabinet of the machine and from the right in FIG. 3;

FIG. 5 is a flow diagram of the refrigerating appara- FIG. 6 is a wiring diagram showing the electrical circuits for the machine of FIG. 1;

FIG. 7 is a wiring diagram of a modified machine which permits water to run onto the freeze plate during harvest of the ice;

FIG. 8 is a view similar to FIG. 2, but on a smaller scale, and showing a modified machine in which multiple freeze plates are utilized;

FIG. 9 is a view similar to FIG. 8 showing a machine modified to produce ice cubes, and

FIG. 10 is a wiring diagram of the machine illustrated in FIG. 9.

Referring now to the drawings, FIG. 1-6 illustrate a preferred embodiment of the invention wherein the ice making machine is enclosed in a cabinet 10, that may be thermally insulated and which is generally divided into a working or refrigeration compartment 24 and a storage compartment 34. The compartment 34 is for the storage of ice made in and harvested from the apparatus in the refrigeration compartment 24 and comprises a bottom insulated wall 32, outer insulated walls 33, an upright insulated Wall 22, insulated cover 59, and a stain less steel sliding door 66 in the cover 59 and permitting access to the storage compartment 34. Cover 59 is a horizontally elongated section which overlays both compartments, and is aflixed with a metal trim for easy lit to the lower section of the cabinet. The cabinet Walls of at least the ice storage compartment are of conventional structure wherein insulating material is disposed between an outer metal shell and an inner metal liner.

An evaporator tray 12 is mounted in the upper section of the compartment 34 by depending arms or supports 14 on a pivot 13, and preferably, normally disposed at an angle of approximately 15 to the horizontal. The evaporator 12 comprises two superimposed plates welded together with fluid tight passages 71 therebetween. Conveniently, the lower plate may be embossed to provide the refrigerant expansion or conveying passages 71 between the plates. The upper surface of evaporator '12 is preferably flat and smooth to receive water to be frozen, and provided with upright flanges on its two sides to retain the water as it flows along the upper surface. The evaporator 12 is of conventional design and is therefore not illustrated in detail. The supports 14 are secured one on each side of plate .12 and offset from its center, and the pivot shaft 13 is mounted in hearings or brackets 15 which are secured to a horizontal frame member 16. 'Ihe supports 14 are preferably made of aluminum or other nonrusting material while the pivot shaft 13 is preferably made of brass for the same reason.

Integrally cast on supports 14 are a pair of arms 17 extending in opposite directions. Each arm threadedly receives an adjusting screw 18 for limiting the pivotal movement of the supports '14 and attached plate and shaft 13. As illustrated in :FIG. 2, the plate 12 is shown in its freezing position with one limit screw 18 contacting the frame member 16. When the freeze plate 12 moves to its harvest position, shown in FIG. 3, the other screw '18 contacts frame member 16 and prevents turning movement beyond approximately 5". A different amount of rotation may be obtained by adjustment of screws 18.

' A brass rod 19 is secured to One of the support members 14 in such manner as to extend substantially in desired position on rod 19. By changing the position of the adjustable weight 20, the thickness of the slab "of ice frozen on the evaporator 12 can'be adjusted fiiom A" to A" in thickness.

Mercury switches 25 and 26 are also secured to the freezing plate 12 to be operated by its movement. The switches' may be attached to the support 14, as illustrated in FIG. 2, by a bracket or other means, and so positioned that when the'plate 12 is in the upper or ice making position, the switch 25 is open and the switch 26 is closed. When the freeze plate 12 moves, to the loweror harvest position, the switch 25 makes or closes its contacts, while the switch 26 opens or breaks. These switches control the start and stop of the ice harvesting phase and the flow of water to the evaporator 12, as will be more'fully described hereinafter;

The evaporator plate 12 forms part of a closed refrigeration system. The interior passages of plate 12 are provided with inlet and outlet conduit connections 27, 28 which are flexible to permit movement of the plate, and which connect the plate with a refrigerant translating device 60 mounted within the compartment 24.

FIGURE diagrams the fluid flow in the elements of the refrigerant translating device 60. Refrigerating system 60 comprises a motor compressor unit 61 connected to a condenser 62 which may be cooled in any suitable manner, as by a fan driven by' motor 78. Condenser 62 is connected to a receiver 63 by conduit 64'. A conduit 70 connects receiver 63 with passages 71 in evaporator 12 at inlet 27. A thermostatic expansion valve 65 is interposed in conduit 69 and normally closes this conduit to prevent passage of hot fluid to the evaporator 12 during refrigeration thereof.

Means is provided for flowing a film of water overthe evaporator 12. This meansihcludes a header in the form of a tube 29 of rectangular shape, FIGS. 2 and 4, having a plurality ofsmall holes or orifices 30 along its length. A water supply pipe 35 may be secured in any suitable manner to connect the tube 29 with a centrifugal pump .36 of conventional construction located in the bottom of sump 37. A valve 38, actuated by a .iloat, not shown, controls the flow of water through a water main into. the sump. .A strainer,'not shown, is interposed in the main water line ahead of the valve 38 to prevent foreign matter from entering the valve. A

stainless steel pan '39 covers the entire refrigeration compartment 24' below the evaporator 12 to catch'the excess water, not frozen in passage over the evaporator,

for return to the sump 37. e 1

The crusher mechanism 40 is mounted by means of bolts 53 near the upper edge of wall 22 separating the storage compartment 34 from tberefrigeration compartment 24. I The crusher body 41 is of cast aluminum or other suitable rust-free material and provided with a series of fixed, parallel jaws 42 formed integrally thereon A brass crusher shaft 43 is drilled and tapped to .receive interchangeable and replaceable threadedbrass fingers 44. The crusher body 41 is provided-with end flanges 45, machined to receive ballbearings 46 and water and moisture seals 47. Bearing cups 48 and remined accumulation of ice therein. 'nected'at one e'nd to a tube which, at its other end,

7 4 tainer rings 49 secure the crusher shaft 43 properly aligned and with the bearings sealed against moisture from the ice being crushed. The fingers 44 are preferably made of brass rod or other rust resistant material. Fingers of different length may be substituted to break the ice sheet into chips of any desired length.

Preferably the crusher fingers 44 are mounted spirally on the shaft 43 so that all of the fingers will not strike the ice slab simultaneously. The fingers are spaced apart equally so that as the shaft 43 turns the fingers will successively strike the ice slab, breaking it on impact, andthe fingers will move down between the vertically extending fixed 'jaws carrying the broken. chips in this direction. A drive pulley 50 is secured to one end ofcrusher shaft .43 and, by means of V-bel 52,

is driven by motorv 51 mounted in the compartment 24 and operated at 430 r.p.m. The motor 51 may be of conventional construction, approximately horsepower, and operated at approximately 1725 rpm.

FIGURE 3 illustrates how an ice slab, shown in broken lines, during the harvest cycle begins to slide down'evaporator 12 onto the upper surf-aces of crusher jaws 42 and against the shaft 43. V The revolving fingers 44 break the ice into small chips which drop into the storage compartment 34. As has been described, the thickness of the ice slab to .be crushed is dependent on the setting of balance weight 20. The width ofthe ice chips is fixed by the spacing between the fixed crusher jaws 42. The length of the ice chips may be varied by substituting the rotating crusher fingers 44, of diiferent length. a j

The operation of the crusher motor '51'is controlled by a conventional type of pressure control switch 74, FIG. 6,

connected in thegas suctionline 73 at the inlet valve on compressor 61, FIG. 5. The pressure of the refrigerant gas operates a bellows in'switch 74, which opens and closes an electrical contact switch. This control is, adjusted so that it will make contact when the gas pressure rises above 20 p.s.i. The switch contacts will break when thepressure drops. below this setting. In normal opera tion, on the freezing cycle, the gas pressure in suction line 73 will be 14 p.s.i. ,In the harvesting? cycle, the pressure in suction lines 73 will rise to 35 pounds p.s.i. Therefore, when the freezing mechanism goes into a harvest cycle and the gas pressure in suction line 73 rises above 20 p.s.i., it Willicausethe crusher control switch 74 to close and start motor 51. When the harvesting cycle is completed and the machine goes back into a regular freezing cycle, the gas pressure will drop and switch 74 will open to stop the crusher motor 51.

Compartment 34 is provided with a sliding access door 66 at the top for removal of the stored ice. Partition and guard 31,- FIG. 1, is provided to direct the flowof the chipped ice into the compartment and serves as a guard for the crusher mechanism 40.- A suitable drain 68 is provided in the bottom of the storage compartment 34 and runs to the underside of the frame to provide a conventional fitting for drainageof water to a convenient outlet. 'A thermobulb 79'is disposed within bin 34 at a position to be contacted byand responsive to a predeter- The bulb isconis connected with an'expandible and contractible element such as a bellows, mounted in a bin thermostatic switch 76, FIG. 6, of conventional construction. The bulb 79 and the bellows in switch 76 are charged. with'a suitable fluid and then sealed to form a temperature responsive unit for controlling. the operation of the switch 76. When the bin fills with ice to the level of thebulb '79, the resultant cooling of. the bulb, fluid activates .bin

control switch 76 which breaks the electrical circuit to :the compressor 61.to stop .it. -When suflicient-ice is chine components is shown in FIGURE 6. The power source 77 is here illustrated as connected to terminals of a manual on-off switch 80 mounted on the front panel of the machine, see FIG. 1. The compressor motor 61 in series with a conventional pressure control switch 75 and the bin control switch 76, previously described, are connected across the power source in the following circuit: positive main 77, wires 85, 86, motor 61, wires 87, 88, switch 75, wire 89, switch 76, wire 90, closed switch 80 and negative main. Thus, the compressor motor will operate until any one of the series connected switches 80, 75 and 76 opens. The fan motor 78 for the condenser 62 is connected in parallel with the windings of compressor motor 61 by wires 91 and 92, and therefore is energized simultaneously to operate when the compressor motor operates. The crusher motor 51 in series with switch 74 is connected to power across the compressor motor terminals by wires 93, 94 and 95. Operation of the control switch 74 has been previously described.

The water pump motor 36 is energized from power mains 77 by the following circuit: manual switch 80, wire 98, mercury switch 26, wire 97, motor 36, wire 96, switch 75, wire 89, switch 76, wire 90, switch 80 to the negative main. The switch 26 opens the circuit to motor 36 during the ice harvesting period by tilting movement of evaporator 12. Otherwise, the water pump motor will operate whenever compressor 61 operates.

A last circuit for operation of the solenoid 65, which controls the flow of harvesting hot fluid to the evaporator through conduit 69, FIG. 5, runs from the positive main 77, wire 101, mercury switch 25, wire 100, solenoid 65, wire 99, 96, switch 75, wire 89, switch 76, wire 99, switch 80 and return to the negative main 77. Mercury switch 25 is normally open and solenoid 65 closed during the freezing phase. When the evaporator tilts to harvesting position, switch 25 makes to operate the solenoid 65 and open conducit 69 for passage of hot fluid to the evaporator 12.

Operation Referring now to FIGS. and 6 primarily, the operation of the machine will be described.

Assuming that the ice maker is properly connected to a source of water supply, to a drain, and its electrical service is now energized by plugging an extension cord, leading from the cabinet in the motor compressor compartment, into an electrical outlet, electrical current flows from the main 77 through the closed manual switch 80 to the motor compressor unit 61 to cause operation thereof. Current also flows to the water pump 36, cansing it tov pump water over evaporator plate 12. Water fills sump tank 37 to a predetermined level as controlled by float and valve 38. The pump 36 lifts water from the sump 37 into the header 29 from which it is distributed by gravity in the form of a film upon the freezing or evaporator plate 12 through the orifices 30. The compressor unit 61 circulates and withdraws refrigerant vapor through the passage 71 in the plate 12 to cause chilling of the plate, compresses the refrigerant, and forwards the compressed refrigerant to condenser 62 where it is cooled and liquefied, as by circulating cool room air blown by the fan over the condenser. Refrigerant liquefied in condenser 62 flows into receiver 63 where it is further cooled and collected. Liquid refrigerant enters conduit 70 and flows through the dryer 64 to the expansion valve 67, and then into the passage 71 of the plate 12, where it vaporizes, absorbing heat from the freezing plate. The vaporized refrigerant is returned through conduit 73 to the compressor unit 61.

The refrigerating effect produced by plate 12 causes the water film flowing over its surface to freeze and accumulate thereon in the form of a layer or slab of ice. When the thickness of the ice on plate 12 reaches the predetermined point, the weight of the ice overbalances counterweight 20, causing the plate 12 to fall or turn into its harvesting position, see FIG. 3. This movement closes the mercury switch 25 and and energizes the solenoid in valve 65, to open the valve. Hot gaseous refrigerant will then circulate from the condenser 62 and the receiver 63 through conduit 69 and then through the passage 71 in the freezer plate 12, and thereafter through conduit 73 back to the compressor unit 61, which continues to operate. The movement of plate 12 to harvesting position simultaneously opens mercury switch 26 to stop the water pump motor 36 and the flow of water over plate 12. Heat of the hot gaseous refrigerant flowing through the passages 71 is conducted to the slab of ice formed on plate .12 to melt and break the bond between the ice and the plate. The released slab of ice slides off the inclined plate 12 into. the crusher mechanism 40.

As explained in the harvest phase, when solenoid valve 65 is opened, directing the hot gas flow from the condenser and receiver to the plate 12, the pressure of the gases in the suction line 73 rises. When this pressure exceeds the predetermined setting on switch 74, the switch closes and energizes the crusher motor 51. Since there is a time delay during melting of the ice on the plate 12 before the ice slides to the crusher, the crusher motor 51, actuated by the immediate rise of pressure in conduit 73, will be in operation at the time the ice slab moves from the plate 12. With the crusher shaft 43 in motion as the ice comes into position on the crusher body 41, the fingers 44 strike the ice breaking it into small chips which fall between the stationary crusher jaws 42 into the storage bin 34.

When the slab of ice has completely removed itself from plate 12, the counterweight 20 moves the plate 12 about axis 13, returning it to the freezing position, shown in FIG. 2. This movement opens mercury switch 25 which, in turn, de-energizes solenoid valve 65 to close conduit 69. The closing of the solenoid valve 65 places the refrigeration system into a freezing cycle with cooled liquid refrigerant flowing to plate 12 through conduit 70. The return movement of plate 12 to freezing position also closes mercury switch 26 energizing the motor of water pump 21 to again feed water over plate 12 for a second freezing phase or cycle.

The above described operation repeats automatically until the ice storage bin is filled to the level of therrnobulb 79, FIG. 1. Cooling of this element opens switch 76, stopping the compressor motor 61 andthe other machine elements. When the supply of stored ice has dwindled to a predetermined level, thermobulb 79* will warm sufficiently to close switch 76 to again start the machine and refill the storage compartment.

FIG. 7 is a wiring diagram for a modified form of ice making machine in which the mercury switch 26, its electrical connections and function are omitted. -In all other respects, the machine and its wiring are identical in structure and operation with that illustrated in FIGS. 1-6. Omission of switch 26 allows the water pump 36 to operate continuously during the harvesting phase as well as during the freezing phase. The continuous flow of water over plate 12 will aid in warming of the formed ice slab and permit faster removal of the ice into the crusher. The flow of water will also wash from plate 12 any small fragments or chips thrown onto the plate during operation of the crusher.

In the modification shown in FIG. 8,v a plurality of evaporator plates are used for increasing the production of ice. One or more additional evaporator plates 82 are fixedly securedone on top of the other in inclined positions by frame members 83, 84. Evaporator 12 will operate in the manner described to control the change from freeze to harvest. The gas lines 71 and 73 are extended to plate 82 and another water header 29 positioned above plate 82. Plate 82 is inclined at such an angle as to discharge the ice slab formed onto the crusher 40, which is of sufficient size and strength to break several ice slabs into uniform chips simultaneously. 7

In the modification illustrated in FIGS. 9 and 10, a mawhich is mounted in brackets 104 aflixed to thetop frame 7 109 of the cabinet compartment 24. Counterweight 20 is mounted above plate 102 for adjustable positioning on rod 106. Stops, not shown, are normally provided to limit the turning movement of plate 102 to approximately". The mercury switches 25 and 26 are preferably mounted on the upper surface of the evaporator so as to move with it and thus control the harvest and freeze cycles as previously described;

' Spray nozzles 108 are positioned under plate 102 and connected to water pump 36. In the freezing cycle, water is sprayed upwardly into the cups 103 on the underside of plate 102. When ice cubes have formed in cups 103 to a sufiicient thickness and weight to overcome the balan'ce elfected by counterweight 20, the plate 102 will rotate into a harvesting position. Then, hot refrigerant gas circulates through plate 102. The bond between the frozen cubes and the cups 103 is overcome by melting and the formed ice cubes drop on harvest racks 105, preferably formed of stainless steel rods spaced close enough to prevent the ice cubes falling through into the water pan 39 below. The rods 105 are positioned at such an angle as to cause the ice cubes to slide into the storage compartment 34. A splash curtain 107 of vinyl or other suitable material is hung from a shield 110 so as to prevent sprayed water in the freezing compartment from entering the storage compartment. The weight of the ice cubes moving along harvest rack 105-is sufficient to move the splash curtain 107 aside so the cubes move freely into the storage compartment 34. When the ice cubes have dropped from plate 102, it will turn back to its freezing position by effect of the counterweight 20 carrying the switches 25 and 26 into operation to effect the freezing cycle. 7

It should be noted that in directly producing ice cubes or forms of other shape, the modified machine omits the crusher mechanism, its motor 51 and their supplementary control and wiring elements. FIG. 10 shows the wiring of the machine'with these parts omitted. In all other respects, the electrical and physical operation is identical with-that described in detail with respect to FIGS. l-6. i Although certain specific embodiments of the invention have been shown and described, it is obvious that many modifications thereof are possible. The invention, therefore, is not to be restricted except insofar as is necessitated by the prior art and by the spirit of the appended claims.

What is claimed and desired'to be secured by Letters Patent is: I a V '1. In automaticice making apparatus, the combination comprising a substantially rectangular hollow plate evap orator mounted for pivotal, movement fiom a less inclined freezing positiontoa more inclined harvesting position, inlet and outlet conduits for refrigerant fluid on said evaporator, a valve for admitting a refrigerant to said evaporator, a second valve for admitting a relatively hot frozen against an outer surface of said evaporator, means controlled by the movement of said evaporator from said freezing to said harvesting position for opening said second valve to admit hot gas to the evaporator, and means counter-balancing the evaporator so as normally-to be disposed, in said freezing position and the pivot axis of the evaporator being ofl'set from the transverse center line of the evaporator whereby the weight of a predetermined thickness of ice uniformly formed on the evapo rator will be greater on the low end than on the high end thereof and will cause the evaporator to tilt into its harvesting positi'o'n. a 7

- 2. The combination according to claim 1 wherein'said gas to said evaporator, means fordirecting a liquid to be pivotally mounted evaporator is additionally provided with adjustable means for limiting its pivoting movement from said freezing position to said harvesting position.

3. The combination according to claim 1 wherein said pivotally mounted andcounter-balanced evaporator comprises a weight movably secured to the evaporator and meansf-or selectivelyfixing theweight in different'positions at varying'distance from the evaporator pivot, whereby different predetermined thicknesses of ice may be formed on said evaporator by preselected positioning of said weight.

4. The combination according to claim 1 wherein said means for opening the hot gas valve comprises a mercury switch secured to the evaporator for movement therewith and electrical means operated by making of the mercury switch to actuate said valve.

5. The combination according to claim 4 wherein said pivotally mounted evaporator is provided with a second mercury switch secured thereto for movement therewith, said second mercury switch controlling the same means for directing liquid to be frozen against said evaporator to stop the flow of such liquid when the evaporator tilts to harvesting position and to start the flow of liquid when the evaporator is returned to its freezing position.

6. In automatic ice making apparatus, the combination comprising a hollow plate evaporator, inlet and outlet conduits on said evaporator, means for circulating a refrigerant in said evaporator through said conduits, means for directing water against an outer surface of the evaporator to be frozen thereon, a motor driven ice crusher, means responsive to a predetermined weight of ice formed on the evaporator for admitting hot fluid to the evaporator to thaw ice formed thereon, means for directing the ice to said crusher, and means, responsive to increase of pressure in said outlet conduit arising from presence of hot fluid, for controlling the start of said crusher motor. 7

7 In automatic ice making apparatus, the combination according to claim 6 wherein said means to start the crusher motor is also responsive to a lowering of pressure in said outlet conduit, arising from absence of hot fluid, to stop said crusher motor.

8. In automatic ice making apparatus, the combination comprising a hollow evaporator plate of substantially rectangular flat shape pivotally mounted on a horizontal axis transverse of the plate and at one side of its center of gravity so that the plate is normally disposed in a freezing position unbalanced in one degree of inclination for rocking movement to an ice harvesting inclined position of a different degree of inclination, means for directing against the upper portion of an outer surface of said plate a liquid which will flow by gravity down said surface, inlet and outlet conduits for refrigerant fluid on said plate, means holding said plate in said freezing position until the liquid flowing down said surface freezes to form thereon a predetermined quantity of ice, a valve for admitting a relatively hot gas to said plate, and means controlled by movement of said plate from said freezing to said harvesting position consequent upon formation of said predetermined quantity of ice thereon overbalancing said plate for opening said second valve to admit hot gas to theplate for freezing the ice formed thereon for gravitational sliding movement off the plate in said ice harvesting inclined position.

References Cited'in the file of this .patent UNITED STATES PATENTS 1,815,383 Scullen July 13, 1931 2,086,622 Kagi July 13, 1937 2,105,460 Gaugler Jan. l1, 1938 2,279,116 Fink ...Apr. 7, 1942 2,299,866 Willard -1. Oct. 27,1942 2,429,851 Swarm Oct. 28, l947 (Other references on following page) Linfor June 20, 1950 Calling Apr. 6, 1954 Mason May 4, 1954 Ayres June 29, 1954 5 10 Deuzer Nov. 1, 1955 Murdock Jan. 17, 1956 Iaeger May 13, 1958 Morgan May 27, 1958 Thomas May 26, 1959

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