Weigh Bar Switch Arrangement For Automatic Ice Maker

Abstract

A weigh switch to stop production of an automatic ice maker whenever the ice collecting bin is either filled with ice pieces or removed from its carrier means. An electrically conductive bin weigh bar is pivoted on a terminal post to provide a first lever arm loaded by the carrier means and a second counterbalancing lever arm which pivots the bin weigh bar from a first open circuit position to a second ice maker energizing position electrically contacting an overlying conductive pivoted ice weigh bar when the bin is inserted in the carrier means and the combined weight of the bin and its contents is below a predetermined amount. In response to the weight of a filled bin, the bin and ice weigh bars are pivoted in unison to a third open circuit position thereby terminating the production of ice pieces.

Description

This invention relates to automatic ice makers for domestic refrigerators and in particular to a counterbalanced weigh bar electric switching system for automatically stopping the production of ice pieces whenever the collecting bin is either filled with ice pieces to a preselected load or the bin is dislodged from the ice maker.

In one form of improved automatic ice maker disclosed in the Eyman, Jr., et al. U. S. Pat. No. 3,540,227, owned by the assignee of the instant invention, a mold is provided with an ejecting means for transferring formed ice pieces to a subjacent collecting bin. In the Eyman patent a commutator timing gear is provided together with a mold temperature sensing thermostat which have cooperating spring contacts for controlling the filling, freezing and ejecting cycles of the ice maker. One of the commutator contacts is actuated by a pivotal ice collecting bin supporting carrier by means of a cooperating weak and strong coil springs arrangement stopping the production of ice pieces whenever the bin is disloged or removed from its inserted position or when the bin is loaded with ice pieces to a preselected weight. Such an arrangement requires the individual calibration of each ice maker because of the inherent variability of coil springs, thus materially increasing the cost of manufacture of each ice maker unit.

It is an object of the present invention to provide an automatic ice maker having an improved means for sensing the load condition of an ice piece collecting bin pivotally supported from a first lever arm of an electrically conductive pivoted bin weigh bar by knife edge means wherein the bin weigh bar is rotated about its fulcrummed support to a first open circuit position by a counterbalancing second lever arm when the bin is dislodged from the ice maker, and wherein the bin weigh bar is rotated to a second circuit closing position with the second lever arm in electrical contact with an overlying ice weigh bar under the load of a positioned empty or partially filled ice collecting bin and wherein the second lever arm pivots the ice weigh bar in unison therewith to a third open circuit position in response to the weight of a predetermined load of ice pieces in the bin thus automatically stopping the operation of the ice maker.

Further objects and advantages of the present invention will be apparent from the following description, reference being had to the accompanying drawings, wherein a preferred embodiment of the present invention is clearly shown.

In the drawings:

FIG. 1 is an irregular vertical sectional view through a refrigerator embodying an air cooled automatic ice maker illustrating the invention;

FIG. 2 is an enlarged fragmentary vertical sectional view of the ice maker of FIG. 1 showing the drive and control mechanism;

FIG. 3 is a sectional view taken along line 3--3 of FIG. 1;

FIG. 4 is an enlarged partial horizontal sectional view taken along line 4--4 of FIG. 1;

FIG. 5 is a fragmentary vertical elevational view partly in section taken along line 5--5 of FIG. 3;

FIG. 6 is a view of the balance beam weigh bar showing dimensional ratio of its lever arms;

FIG. 7 is a schematic wiring diagram.

Referring now to the drawings and more particularly to FIG. 1, there is shown the upper portion of a frost-free type of household refrigerator 20 with an upper below-freezing compartment 22 enclosed by an insulated door 24 and a lower above-freezing compartment 26 enclosed by a lower insulated door 28. These compartments are surrounded by the insulated side, top, bottom and rear walls 30 separated by horizontal insulated wall 32 containing an evaporator compartment 34 provided with finned evaporator 36 having vertical fins extending from the front to the rear of the compartment 34. Evaporator compartment 34 is provided with an inlet 38 at the front communicating with the front of the below-freezing compartment 22 and additional inlets (not shown) communicating with the top of the above-freezing compartment 26. At the rear, the compartment 34 connects with a shroud 40 communicating with the entrance of a centrifugal fan 42 which is driven by an electric motor 44 housed in a rear wall 30 of the cabinet. The cooling arrangement for the compartments may be similar to that shown in U.S. Pat. No. 3,359,750 issued Dec. 26, 1967, or U.S. Pat. No. 3,310,957 issued Mar. 28, 1967, owned by the asignee of the present application and which may be referred to for further details of construction of the refrigerator.

The fan 42 is provided with an upwardly extending discharge duct 46 having a distributor 48 at the top which distributes the discharge of air through the below-freezing compartment 22. Evaporator 36 is maintained at suitable below-freezing temperatures such as -5.degree. to -15.degree. F. to maintain the compartment 22 at the temperature of 0.degree. F. or below.

For providing special cooling for the automatic freezer the distributor 48 is provided with a laterally extending discharge duct 50 extending along the intersection of the rear and top walls. Behind automatic ice maker 52 the laterally extending duct 50 is provided with wide discharge nozzle 54 which discharges the cold air directly onto the top of the ice maker 52 and particularly onto the top of its ice piece forming mold 56.

As seen in FIGS. 1 and 2 the mold 56 is provided with two rows of pockets 58 containing four pockets in each row and has an upwardly flanged rim 60 extending around the short and long sides thereof. The mold 56 of the ice maker is supplied with water or any other liquid to be frozen from a pressure water system or other liquid under pressure to a solenoid control valve 62 which controls the flow of water through pipe 64 extending through the insulation of the top wall to a suitable discharge device 66 in the top wall of the below-freezing compartment 22 above the front pockets 58 of the mold 56. The ice maker 52 is provided with a wide U-shaped frame 68 which surrounds the mold 56 and is fastened to the adjacent side wall of the freezing compartment 22 by suitable screws. Below the frame 68 is a rectangular bin carrier 70 having, adjacent the rear, a pair of upwardly extending projections 72 positioned respectively adjacent the inner surfaces of the frame side walls and having outwardly directed pivot pins 74 extending through aligned apertures in the side walls such that the carrier 70 is pivoted about a horizontal axis. By virtue of this arrangement the weight of the bin and carrier biases the forward end of the carrier in a downward direction about the pivotal axis of pins 74.

As a result it will be appreciated that the rear portion of the carrier 70 together with an inserted bin 78 is supported by the pivotal pins 74 for movement about a substantially horizontal axis that is displaced rearwardly from the center of gravity of the carrier and bin while the forward portion of the carrier and bin is supported by suspension means in the form of a weigh shaft or rod 243 displaced forwardly from the center of gravity of the carrier and bin. In the disclosed form of the invention the axis of the support pins 74 is located approximately one and three-quarters inches closer to the center of gravity of the combined carrier and bin than the vertical axis of weigh rod 243. Thus, for example, if the combined weight of the bin and carrier is about 1.80 pounds the weight will be distributed so that a downward pull or force of about 0.70 pounds will be applied to the weigh rod 243 and a slightly larger force of about 1.10 pounds will be applied to the pivotal pins 74. By virtue of this arrangement the carrier and fully inserted bin create an unbalance or moment such that the front end of the carrier tends always to gravitate or pivot in a downward direction about the axis of pins 74.

In the disclosed form of the invention the mold delivers eight ice pieces into the bin, having a total weight of about one-third pound, during each harvest of the ice maker. Consequently, the bin load on weigh rod 243 is proportionally increased in stepped increments. A weigh bar electrical switch arrangement to be described is designed to sense a percentage of the total weight of the carrier and filled bin applied thereto by means of the downward pull on weigh rod 243 proportional to a predetermined number of ice harvesting cycles. In a manner to be explained the final harvest of ice pieces discharged into the bin 78 creates a cumulative load which overshoots the neutral balance condition of the weigh switch by a predetermined amount to produce a triggering downward pull on weigh rod 243 to insure that the automatic ice maker control circuit is immediately opened.

It will be noted that the bin carrier 70 is provided with supporting ledges 76 on its inner sides for slidably supporting the laterally extending flanges 80 of the box-shaped bin 78 while the bin 78 is provided with a double flange 82 at the front to serve as a handle.

A description of the ejection and control systems of the ice maker is unnecessary herein since they are described in the above-mentioned U.S. Pat. No. 3,540,227, the disclosure of which is incorporated herein by reference.

For accessibility all the mechanism and controls are located at the front of the freezer with the tray rotating and twisting mechansim disclosed in U.S. Pat. No. 3,540,227, and the control system being located in the housing 127 while an electric driving motor 129 and the wiring are located on the front face of wall or mounting plate 133. The housing 127 and plate 133 are preferably formed from suitable plastic material. Substantially the entire operating and control mechanism are mounted upon the irregular plastic upright plate 133 which closes the housing 127 to form compartment 135. The front face of plate 133 supports the drive motor 129 having its final drive shaft extending through the dividing wall or electrical control plate 133 and provided with a drive pinion 139 on the opposite side which continuously meshes with a large driven gear 141. The large gear 141 has an apertured hub 191 (FIG. 5) rotatably mounted in a removable manner by a suitable snap retainer 192 on the inner shaft end of hexgon collar bolt 143. The outer threaded end of bolt 143 extends through opening 144 in boss 145 on wall 133 and is fixedly secured thereto by lock nut 147 and its collar 148.

The large gear 141 is recessed to receive and hold in position the thin brass nickel plated commutator 193 which is shown bonded to the face of the gear 141 nearest the wall 133. As seen in FIG. 3 the commutator 193 includes a fill projection or segment 195 cooperating with a spring contact and terminal member 197 to measure the fill period by the time period required for the fill projection or segment 195 to move past the upper end of the spring contact 197. The commutator 193 also includes a delay projection or segment 199 which cooperates with the delay or stop switch arm 221 having a ball type spring contact end which normally engages the delay and fill segments 199 and 195 of the commutator 193 and during the remainder of the time contacts the plastic surface of the gear 141. The stop switch arm 221 is in electrical continuity with threaded terminal post B which is in turn electrically connected to terminal "I" of thermostatic relay 283 via lead 222.

As seen in FIG. 4 the weigh rod 243 is vertically slidably mounted through the aperture 249 in the bottom of the upright dividing wall 133 and projects through the bottom thereof and through a slot 245 in the front cross member 248 of the bin carrier 70. The bottom of the weigh rod 243 is provided with a C-shaped disc retainer 247 which is keyed thereto and which supports the front cross member 248 of the bin carrier 70.

The weigh rod 243 has an enlarged cylindrical upper head portion 250 integrally molded on the upper end thereof formed with a transversely extending notched portion 251 having horizontally disposed opposed upper and lower surfaces in vertically spaced dimension to receive therein the relatively short lever arm 252 of an electrically conducting balance beam or bin weigh bar 254 fulcrummed on wall 133 by pivot terminal post A below pivoted ice weigh bar 256. The bin weigh bar 254 which is in electrical continuity with terminal post "A" is pivoted in a vertical plane to extend perpendicular to the axis of the post "A" such that the bin weigh bar 254 is counterbalanced to its horizontal position.

As best seen in FIG. 6 the bin weigh bar is shown diagrammatically in its counterbalanced horizontal position such that its relatively short lever arm 252, formed with an upwardly and outwardly tapered surface knife edge contact 255, designed to engage with a planar metal surface provided by a U-shaped clip 258 which may be snapped into the weigh rod notch 251. The weigh bar 254 has a relatively long lever arm 260 functioning as a counterbalance whereby the beam 254 is unbalanced and tends to gravitate the long lever arm in a clockwise direction to a first generally horizontal open circuit position in engagement with a first stop boss 262. The distance L.sub.1 shown in FIG. 6, between the upper marginal edge 257 of the lever arm 260 and the fulcrummed pivot post "A" is of the order of 15 times the relatively short lever arm 252 distance X.sub.1 between the knife-edge 255 and pivot post "A." Thus, in the disclosed form the weigh bar 254 develops a ratio of about 15:1 for transmitting the weight of the inserted bin vertically therethrough so as to be multiplied thereby. For example, in the present embodiment the distance L.sub.1 is of the order of 1.875 inches and the distance X.sub.1 is of the order of 0.125 inches.

An elongated electrically conductive ice weigh bar 256 is pivoted on pivot pin 263 whose threaded end as seen in FIG. 5 is secured by nuts 264 to wall 133. The pivot pin 263 of the ice weigh bar 256 is positioned outboard of the bin weigh bar contact edge 257 and extends lengthwise in a direction opposite to the direction of the relatively long lever arm 260.

The ice weigh bar 256 is of a length such that its free end 265 extends outboard of the knife edge 255 a sufficient distance such that the ice weigh bar 256 tends to gravitate in a downward counterclockwise direction (FIG. 6) toward a horizontal closed circuit position spaced above and generally parallel to the first or counterbalanced open circuit position of the underlying bin weigh bar 254. In its closed circuit position the ice weigh bar free end 265 is supported on a fixed electrical contact in the form of threaded terminal post H having a pair of securing contact nuts 267 and 268 thereon between which spring switch arm 225 is retained in electrical continuity with post H.

In operation the bin weigh bar 254 is designed so that with the bin 78 outwardly displaced or removed from the freezer the bar 254 is in its generally horizontal dashed-line first open circuit position (FIG. 3) engaging first stop boss 262 such that its marginal edge 257 of long lever arm 260 is spaced in parallel fashion from the underside of the generally horizontal ice weigh bar 256. When the bin 78 is fully inserted in carrier 70 the short lever arm 252 is rotated slightly in a counterclockwise direction from its overbalanced position (as viewed in FIG. 4) and the downward pivoting force on lever arm 252 will effect an upward pivotal movement of lever arm 260 a proportionately greater distance to a second closed circuit position operative to provide an electrical path between marginal edge 257 and the underside of the ice weigh bar 256 and as a result electrical continuity is established between post A, fixed contact post H and spring switch contact arm 225 having a rounded-nose contact 270 in continuous contact with the commutator 193.

The circuit for the ice maker, partially shown in the FIG. 7 schematic, is carried on the mounting plate 133 covering the housing 127. After the mold has been filled with water the thermostatic switch 283 has a movable contact 302 which closes to its fixed terminal contact "I" on a rising predetermined temperature, sensed by tube 285 at temperatures of about 19.degree. F .+-. 1.degree. F., which means that there is no continuity via line 284 from thermostat terminal contact "III" to post A through the weigh switch assembly, to post H, arm 225, commutator 193, arm 279 of post D connected to power line 290 via fixed spring contact arm 225 and commutator 193 rendering the motor circuit incomplete. The ice bin 78 is empty and in position in the carrier 70. When the ice pieces are frozen and the sensing tube 285 temperature drops to a predetermined temperature, which in the disclosed form is about 16.degree. F. .+-. 1.degree.F., the thermostat movable contact 302 closes to fixed terminal contact "III" completing a circuit to post A, through the weigh switch bars, terminal post H and fixed spring contact 225, to post D connected to power line 290 completing a circuit to the motor 129 and the other side of the line 291. This begins the harvest cycle. As commutator 193 is attached to the large gear 141, which is driven directly off of the motor pinion gear 139, whenever the unidirectional motor 129 runs, the commutator 193 must also rotate in a clockwise direction as viewed in FIG. 3.

As the commutator continues to advance until the holding switch 267 connected to terminal post C is closed by moving past notch 269 which completes the motor 129 circuit directly to the commutator 193. It is at this point that the mold 56 begins its first clockwise twist and the circuit cannot be interrupted by the weigh switch bars until the first twist has been completed and the tray has been returned to a normal horizontal position and on past to a position just before the ice pieces fall from the mold 78.

Before the holding switch 267 opens the delay switch 221 will close. When the holding switch 267 has opened the only way the motor 129 can be energized to complete the ice making cycle is for the thermostat sensing tube 285 to warm up to the predetermined 19.degree. F. temperature causing movable contact 302 to close to terminal contact "I." The holding switch 267 opens when the mold has been rotated through approximately a 45.degree. angle, with the notch 271 beneath the adjacent end of the spring contact 267 to stop the ice maker at a desirable time and not when the mold is under a twist.

Terminal F of the fill switch 197 is closed when its end engages fill projection 195, completing the circuit from the commutator 193 to the solenoid 306 (FIG. 7) of the fill valve 62. The holding switch 267 of post C is closed via line 289 from terminal II to prevent interruption of the motor circuit during the "Fill" interval which is about a 12 second period.

A positive temperature coefficient thermistor heater 307 is positioned adjacent the bellows 284 of the thermostatic switch 283 and provides a small amount of heat to insure the operating temperatures of the thermostat are controlled by the temperature of the thermostat sensing tube or bulb 285 rather than being controlled by the temperature of the casing of the bellows 284. The heater 307 is connected by line 294 to spring contact 279 of line post D continuously closed to the commutator 193 and line 295 to line post E.

Reference is now made to FIG. 6 which diagrammatically illustrates the weigh bar assembly system which comprises the bin weigh bar 254 supported on the fixed pivot pin A for pivotal movement or displacement in response to the ice storage bin forces acting on the bar 254. In the disclosed form the forces include the variable force f.sub.1 which includes the force of the bin carrier 70 (F.sub.c) and the force of an empty or partially full ice collecting bin 78 (F.sub.b) while the force of the carrier and a full bin of ice pieces if F.sub.t. With the relationships states the following force conditions exist.

1. For f.sub.1 < F.sub.c + F.sub.b no electrical continuity between A and H.

2. for F.sub.c + F.sub.b .ltoreq. f.sub.1 < F.sub.t electrical continuity exists between A and H.

3. for f.sub.1 .gtoreq. F.sub.t no electrical continuity exists between A and H.

Relationship (1) demonstrates that when the bin 78 is removed from the carrier 70 the weight of the carrier alone producing variable force f.sub.1 is insufficient to pivot bin weigh bar 254 in a counterclockwise direction (as viewed in FIG. 6) from its horizontal overbalanced position engaging stop boss 262. In the disclosed form the effective counterclockwise moment acting on the bin weigh bar 254 because of the variable force f.sub.1 is exerted at knife edge 255 on the relatively short first lever arm 252, whose length X.sub.1 is of the order of 0.125 inches.

The weight W.sub.1 of the bin weigh bar 254 acts as a counterweight through its center of gravity (c.g.) with an effective moment arm Y.sub.1 of about 1.051 inches to create a total effective clockwise unbalanced moment on the bin weigh bar 254 in opposition to the counterclockwise moment created by the bin carrier 70 with the bin 78 removed to prevent pivotal movement of the bin weigh bar 254 from its horizontal static equilibrium position engaging limit stop 262.

Relationship (2) demonstrates that when the bin 78 is inserted in the carrier 70 the variable force f.sub.1 is equal to or greater than a predetermined load, which is about 0.7 pounds in the form shown, and will create a moment sufficient to overcome the constant load W.sub.1 to pivot the bin weigh bar 254 in a counterclockwise direction causing edge 257 to come to a second static position in contact with the underside of beam lever 256 and establish electrical continuity between terminals A and H. In this statically balanced or neutral position, shown in solid lines FIG. 3, the bin weigh bar 254 and ice weigh bar 256 act as a compound weigh bar lever system with variable equal and opposite force f.sub.2 being exerted on the bin weigh bar 254 through a moment arm L.sub.1 and the ice weigh bar 256 through moment arm X.sub.2.

The relationship (3) demonstrates that when the total moment produced on the bin weigh bar 254 by two variable forces f.sub.1 and f.sub.2 acting on the bin weigh bar 254 on opposite sides of its fulcrum pivot and in opposite directions about the fulcrum pivot A do not cause the bin and ice weigh bars to pivot from their neutral position of FIG. 3 until the moment of the constant loads W.sub.1 and W.sub.2 is overcome by the moments of the variable forces f.sub.1 and f.sub.2 acting through their lever arms X.sub.1 and X.sub.2 respectively. This occurs when the variable force f.sub.1 equals or exceeds a predetermined balanced load, which for the form shown is about 4.20 pounds, or the equivalent of nineteen harvests of ice-pieces wherein each harvest weighs about one-third of a pound. Thus within the range of about 0.70 pounds to 4.20 pounds the weigh bars maintain a condition of balance and thereby maintain the weigh switch in an electrically closed state. As successive harvests of ice pieces are deposited in the bin the variable force f.sub.1 increases in stepped increments and is designed such that the eighteenth harvest creates a force f.sub.1 of about 4.10 pounds or a load just below the critical unbalancing weight of 4.20 pounds with the result that the nineteenth harvest creates a force of about 4.25 pounds on the weigh rod to exceed the 4.20 pounds by a weight sufficient to cause a condition of unbalance pivoting the bin and ice weigh bars 254 and 256 in unison to theIr position shown in FIG. 4 wherein ice weigh bar 256 engages stop means 270 to quickly break the electrical continuity between post H and the ice weigh bar 256 and open the weigh switch between terminal posts A and H. The weigh switch will remain in its open position of FIG. 4 and thus prevent further ice harvests being deposited in the bin until a portion or all of the ice pieces are removed therefrom and the bin returned to its inserted position.

While the embodiment of the present invention herein disclosed constitutes a preferred form, it is to be understood that other forms might be adopted.

Claims

I claim:

1. An automatic ice maker including a support frame, a mold pivotally supported thereon, means for supplying liquid to said mold, means for freezing the liquid in said mold, a drive motor, a circuit for controlling said drive motor, means operated by said drive motor for ejecting frozen ice pieces from said mold, a collecting bin, carrier means pivotally supported on said frame adapted to removably support said bin in a position for collecting the ice pieces ejected from said mold wherein the improvement comprises, a weigh switch in said control circuit, said weigh switch including an electrically conducting bin weigh bar pivotally supported intermediate its ends on an electrical terminal post, said bin weigh bar having a first relatively short lever arm at one side of said terminal post and a second relatively long bin counterbalancing lever arm at the opposite side of said terminal post, a weigh rod connected to the free end of said first lever arm and extending downwardly therefrom, said weigh rod having its lower end connected to said carrier means, said bin weigh bar being unbalanced such that said second lever arm tends to gravitate into contact with lower stop means supporting said bin weigh bar in a first substantially horizontally disposed weigh opening position when said bin is removed from said carrier means, an electrically conducting ice weigh bar pivotally supported adjacent its one end in spaced overlying relation to said bin weigh bar, said ice weigh bar pivotal support positioned outboard of said second lever arm's free end, said ice weigh bar being unbalanced such that its free end tends to gravitate into electrical contact with terminal stop means, said bin upon being inserted in said carrier means operative by means of exerting a weight on said first lever arm for pivoting said second lever arm from its first open circuit position to a second weigh switch closed position electrically contacting said ice weigh bar, the weight of said ice weigh bar operative to maintain said second closed circuit position of said weigh bars until a predetermined number of mold ice piece harvests have been received in said bin, said bin weigh bar and said ice weigh bar being responsive to the weight of a final ice piece harvest to pivot said bars in unison to a third weigh switch open position, whereby said ice weigh bar is moved out of electrical contact with said electrical terminal stop means and into engagement with upper stop means such that said drive motor is deenergized to thereby stop operation of said ice maker until a sufficient quantity of ice pieces have been removed from said bin.

2. An automatic ice maker including a support frame, a mold pivotally supported thereon, means for supplying liquid to said mold, means for freezing the liquid in said mold, a drive motor, a circuit for controlling said drive motor, means operated by said drive motor for ejecting frozen liquid from said mold, a collecting bin, a carrier adapted to removably support said bin in a position within the path of movement of the frozen liquid discharged by said ice maker, means on said frame pivotally supporting said carrier for movement about a substantially horizontal axis wherein the improvement comprises, a weigh switch in said control circuit, said weigh switch including an electrically conducting bin weigh bar pivotally supported intermediate its ends on an electrical terminal post, said bin weigh bar having a first relatively short lever arm at one side of said terminal post and a second relatively long bin counterbalancing lever arm at the opposite side of said terminal post, said short lever arm having a knife-edge at its free end, a weigh rod supported on said knife-edge at its upper end and extending downwardly into supporting engagement with said carrier, lower stop means supporting said second lever arm in a first substantially horizontally disposed open circuit position when said bin is removed from said carrier, an electrically conducting ice weigh bar pivotally supported adjacent its one end in spaced overlying relation to said bin weigh bar for movement in a common vertical plane with said bin weigh bar, said ice weigh bar pivotal support positioned outboard of said second lever arm's free end, terminal stop means supporting in electrical conducting fashion the free end of said ice weigh bar in spaced substantially parallel relation to said bin weigh bar, said bin upon being inserted in said carrier operative by means of exerting a downward force on said knife-edge for pivoting said second counterbalancing lever arm from its first open circuit position to a second closed circuit position electrically contacting said ice weigh bar, the weight of said ice weigh bar operative to maintain said second closed circuit contacting position of said weigh bars until a predetermined number of mold frozen liquid harvests have been received in said bin, said bin weigh bar and said ice weigh bar being responsive to the weight of a final frozen liquid harvest to pivot said bars in unison to a third open circuit position, whereby said ice weigh bar is moved out of electrical contact with said electrical terminal stop means and into engagement with upper stop means to deenergize said drive motor and thereby stop operation of said ice maker until a sufficient quantity of frozen liquid has been removed from said bin.

3. An automatic ice maker including a support frame, a mold pivotally supported thereon, means for supplying liquid to said mold, means for freezing the liquid in said mold, a drive motor, a circuit for controlling said drive motor, means operated by said drive motor for ejecting frozen liquid from said mold, a collecting bin, a carrier adapted to removably support said bin in a position within the path of movement of the frozen liquid discharged by said ice maker, said carrier pivotally supported on said frame for movement about a substantially horizontal axis, said carrier being unbalanced with its forward end tending to gravitate in a downward direction, wherein the improvement comprises, a weigh switch in said control circuit, said weigh switch including an electrically conducting bin weigh bar supported intermediate its ends on an electrical terminal post for pivotal movement in a vertical plane, said bin weigh bar having a first relatively short lever arm at one side of said terminal post and a second relatively long lever arm at the opposite side of said terminal post, said bin weigh bar being unbalanced such that said second lever arm tends to gravitate in a first direction, said short lever arm having an upwardly and outwardly tapered knife-edge at its free end, a weigh rod having a notched portion on its upper end forming a horizontally disposed upper undercut surface supported on said knife-edge, said weigh rod extending downwardly into supporting engagement with the forward end of said carrier, lower stop means supporting said bin weigh bar second lever arm in a first substantially horizontally disposed open circuit position when said bin is removed from said carrier, an electrically conducting ice weigh bar pivotally supported adjacent its one end in spaced overlying relation to said bin weigh bar for movement in the vertical plane of said bin weigh bar, said ice weigh bar pivotal support positioned outboard of said second lever arm's free end such that said ice weigh bar tends to gravitate in a second direction, terminal stop means positioned outboard of said knife-edge supporting in electrical conducting fashion the free end of said ice weigh bar in spaced substantially parallel relation with said bin weigh bar, said bin upon being inserted in said carrier operative by means of exerting a weight on said knife-edge for pivoting said second counterbalancing lever arm in said second direction from its first open circuit position to a second closed circuit position electrically contacting said ice weigh bar, the weight of said ice weigh bar operative to maintain said second closed circuit contacting position of said weigh bars until a predetermined number of mold frozen liquid harvests have been received in said bin, said bin weigh bar and said ice weigh bar being responsive to the weight of a final frozen liquid harvest being discharged into said bin to pivot said bars in unison to a third open circuit position, whereby said ice weigh bar is moved out of electrical contact with said electrical terminal stop means and into engagement with upper stop means to deenergize said drive motor and thereby stop operation of said ice maker until a sufficient quantity of frozen liquid has been removed from said bin.

4. The automatic ice maker as claimed in claim 1 wherein the effective length of said relatively long lever arm is of the order of fifteen times the effective length of said relatively short lever arm.