DE69311452T2 - Ice making machine - Google Patents

Description

BACKGROUND OF THE INVENTION

This invention relates to an ice making machine according to the preamble of claim 1. More particularly, this invention relates to a cam control mechanism in an ice making machine in which a plurality of freezing fingers formed on the lower surface of a freezing base plate are immersed in the water supplied to a freezing chamber defined in a water trough so that a freezing operation is carried out and inverted dome-shaped ice pieces are gradually formed around the freezing fingers. The cam control mechanism of the invention successfully carries out a series of cam actions to be caused in accordance with the rotation of an actuating motor for driving the water trough:

(1) Tilting the water trough and returning it to the horizontal position;

(2) supplying hot gas to an evaporator for accelerating the release of the ice pieces in the ice releasing operation and stopping it; and

(3) Refilling the water to be frozen after a cycle of freezing and stopping the same, thereby achieving a simplification of the control system and a reduction in manufacturing costs.

Various types of freezing systems have been proposed for automatic ice making machines for automatically producing a number of ice pieces such as cubes, and they have been suitably used depending on the applications. For example, the following systems are known:

(1) an ice making machine of the so-called closed cell type having a plurality of freezing cells opening downwards, which are delimited by a plurality of partitions which cross each other, into which water is injected upwards into the corresponding freezing cells which are cooled by an evaporator connected to a freezing system, the water being injected from a water trough provided beneath the freezing cells so that ice cubes are gradually formed therein;

(2) an ice making machine of the so-called open cell type having such freezing cells opening downwards, into which water is sprayed upwards directly into the freezing cells without using a water trough so that ice cubes are formed therein; and

(3) a flow-down system ice making machine having a vertical freezing plate, in which water is supplied to flow down a surface of the freezing plate so that a semi-cylindrical block of ice is formed on the corresponding surface.

These three types of ice making machines all use a forced circulation system and comprise a water tank for carrying therein a predetermined amount of water to be frozen, and the water in the tank is fed by a pump to the freezing cells or to the vertical freezing plate provided in a freezing unit, while the unfrozen part of the water is recovered in the tank so that it can be circulated to the freezing unit again. Consequently, auxiliary equipment such as a water tank and a pump for circulating the water to be frozen become necessary in such types of ice making machines. This causes not only a complication of the structure of the machine, but also an increase in production cost and an increase in the size of the machine. Furthermore, a more simplified ice making machine has already been proposed in which freezing fingers extend downward from the lower surface of a freezing base plate provided with an evaporator thereon, the freezing fingers being immersed in a predetermined level of water carried in a water trough so that ice pieces around the freezing fingers This type of ice making machine does not require a mechanism for circulating the water to be frozen between the water trough and the water tank during the freezing operation, so that the structure of the machine can be simplified, which advantageously leads to a reduction in production costs and a downsizing of the machines.

As described above, the last-mentioned ice making machine in which ice pieces are to be formed around the freezing fingers by only dipping them into the water carried in the water trough enjoys a great advantage that the structure of the machine can be simplified. The control system of the machine is not actually necessarily simplified. Namely, in the ice making machine, the freezing cycle and the ice releasing cycle are alternately repeated, and the water to be frozen must be replenished whenever the freezing cycle is started. Further, after the freezing cycle is completed, a hot gas must be supplied to the evaporator after the water trough is inclined and stopped at a predetermined angle so that the falling of the ice pieces formed around the freezing fingers is accelerated by their own weight. It is also necessary to stop the supply of hot gas to the evaporator and supply a cooling medium instead after the ice pieces have fallen down, as well as to allow the water trough, which is stopped in the inclined position, to return to the horizontal position and resume the freezing operation. Consequently, various types of sensors and a complicated control circuit are required for controlling such a series of operations, which disadvantageously contributes little to the overall production cost despite the simplified mechanical structure.

From AU-B-22 730/77 an ice making machine according to the preamble of claim 1 is known. The freezing fingers are dipped into the water in the water trough. The water freezes around the freezing fingers. Clear pieces of ice are formed by permanent Maintain water circulation.

It is therefore an object of the present invention to provide an ice making machine which can produce transparent and clear ice pieces and which does not suffer from the problems of the above-mentioned prior art.

This object is achieved by an ice cream making machine, which has the features of claim 1.

Preferred embodiments of the invention are specified in the subclaims.

The mechanisms of this ice making machine as set out in the appended claims are proposed to overcome the above problems and to successfully achieve the desired object. According to the mechanism of the ice making machine of this invention, in which a plurality of freezing fingers formed on the lower surface of a freezing base plate are immersed in the water carried in the freezing chamber defined in a water trough to carry out the freezing operation and inverted dome-shaped ice pieces are gradually formed around the freezing fingers, the following movements are performed:

(1) Tilting the water trough and returning it to the horizontal position;

(2) supplying hot gas to an evaporator for accelerating the release of the ice pieces in the ice releasing operation and stopping the same; and

(3) Refilling water to be frozen after a cycle of freezing activity and stopping it,

carried out by a series of cam actions caused according to the rotation of an actuating motor for driving the water trough, thereby realizing a simplification of the control system and a reduction in manufacturing costs.

In the cam control mechanism of the ice making machine according to of this invention in which a plurality of freezing fingers formed on the lower surface of a freezing base plate are immersed in the water to be frozen carried in the freezing chamber defined in the water trough, the inclination of the water trough and the resetting thereof to the horizontal position as well as the stopping thereof at such positions are successfully achieved in an ice making machine by a series of cam actions caused according to the rotation of the actuating motor which is a drive source for the water trough inclining mechanism. Further, in addition to the inclination and resetting of the water trough as well as the stopping thereof at such positions, the supply of a hot gas to the evaporator for accelerating the falling of the ice pieces in the ice releasing operation and the stopping thereof and also the replenishment of the water to be frozen after a freezing operation and the stopping thereof are controlled by a series of cam actions according to the rotation of the actuating motor. Consequently, the structure of the control system in the ice making machine can be significantly simplified, which greatly contributes to the reduction of the manufacturing cost as a whole. Further, since a plurality of cam surfaces are formed on a cam plate so that the inclination and resetting of the water trough as well as the stopping thereof at such positions are controlled by the switches provided corresponding to the respective cam surfaces, not only the number of parts can be reduced but also the control system can be simplified.

Furthermore, since the water trough is designed to be pivotally supported on the pivot pins integrally formed on the main body of the ice making machine, the water trough can be smoothly tilted and reset on the pivot pins. Namely, since the load of the water trough is evenly transmitted to the pivot pins, no pre-stress load is applied to the pivot shaft and the connecting rod connected to the pivot pins, thereby achieving smooth pivoting. of the water trough.

Furthermore, since the pivot shaft for tilting the water trough is pivotally supported on the main body of the ice making machine, heat insulation at such portions can be facilitated. Furthermore, the drain pipe provided for the water trough can also serve as a stopper for holding the water trough in an inclined position, so that there is no need for providing an additional stopper, and the number of parts can be reduced, resulting in cost reduction.

BRIEF DESCRIPTION OF THE DRAWINGS

Figure 1 schematically shows a perspective view of a cam control mechanism in an ice making machine according to a first embodiment of the invention.

Figure 2 shows a diagram of a control circuit connected to the cam control mechanism.

Figure 3 shows a timing chart for the control to be effected by the cam control mechanism.

Figure 4 shows schematically in an exploded perspective view a freezing unit in which the cam control mechanism is used.

Figure 5 shows in a vertical section the main section of the freezing unit shown in Figure 4.

Figure 6 shows a partially perspective cut-away view of the water trough shown in Figure 4 as well as the vibrating plate contained therein and a drain for discharging the water to be frozen.

Figure 7 shows schematically in a vertical section the ice making machine in which the cam control mechanism is used.

Figure 8 shows a partially cutaway perspective view of the ice making machine shown in Figure 7.

Figure 9 shows schematically a freezing system to be used in the ice making machine.

Figure 10 shows in a vertical section the main section the freezing unit shown in Figure 5, wherein the vibrating plate rises during the freezing operation.

Figure 11 shows in a vertical section the main section of the freezing unit shown in Figure 5, with the freezing plate descending during freezing operation.

Figure 12 shows in a vertical section the freezing unit in which ice formation is completed, together with the positional relationship between a cam follower and a cam slot.

Figure 13 shows a vertical section of the freezing unit, in which the water trough is tilted and the water remaining in it is partially dispensed.

Figure 14 shows in a vertical section the freezing unit, in which the water trough is stopped in the inclined position and the ice pieces are released while the swing plate is held in an inclined position at a point slightly above the water trough.

Figure 15 shows in a vertical section the freezing unit, in which the water trough is reset to the original horizontal position and the water to be frozen is newly added to the remaining water.

Figure 16 is an exploded perspective view showing the main portion of the cam control mechanism in an ice making machine according to a second embodiment of the invention.

Figure 17 schematically shows in a vertical section the ice making machine in which the cam control mechanism according to the second embodiment of the invention is used.

Figure 18 shows a partial exploded perspective view of the freezing unit in which the cam control mechanism is used.

Figure 19 shows in a vertical section the main section of the freezing unit shown in Figure 18.

Figure 20 shows in a partially cutaway front elevation the water trough inclination mechanism and the rocker plate rocker mechanism shown in Figure 18.

Figure 21 shows schematically in a perspective view the freezing unit shown in Figure 18, which is housed in a box-like Chamber is provided.

Figure 22 shows a partially cutaway front elevation of the freezing unit shown in Figure 18.

Figure 23 shows the appearance of the ice making machine in a perspective view.

Figure 24 shows a partially cut-away side view of the freezing unit shown in Figure 19 with the water trough inclined.

Figure 25 shows a diagram of a control circuit connected to the cam control mechanism.

Figure 26 is an explanatory view of the freezing unit under the swinging of the swinging plate during the freezing operation of the ice making machine, with the swinging mechanism assuming a corresponding posture.

Figure 27 is an explanatory view of the freezing unit after the freezing operation is completed in the ice making machine according to the second embodiment of the invention, with the swing mechanism taking a corresponding position.

Figure 28 is an explanatory view of the freezing unit after the freezing operation in the ice making machine is completed, wherein the swing mechanism assumes a corresponding position, the swing projection of a swing member is retracted from the inclination orbit of the engagement piece of the swing plate.

Figure 29 is an explanatory view of the freezing unit after the freezing operation in the ice making machine is completed, with the swing mechanism and the tilt mechanism assuming respective positions.

Figure 30 is an explanatory view of the freezing unit in the ice making machine in which the water trough is stopped at the inclined position, together with the positional relationship between the cam plate of the inclination mechanism taking a corresponding position and the seventh and ninth switches.

Figure 31 is an explanatory view of the freezing unit in the ice making machine in which the water tray is reset, together with the positional relationship between the cam plate of the tilt mechanism, which takes a corresponding position, and the seventh and ninth switches.

Figure 32 is an explanatory view of the freezing unit of the ice making machine in which the water tray is inclined beyond the horizontal position, together with the positional relationship between the cam plate of the inclination mechanism which assumes a corresponding position and the seventh and ninth switches.

Figure 33 is an explanatory view of the movements of the oscillation mechanism for the oscillation plate in the ice making machine, in which the oscillation projection of the oscillating member is retracted from the inclination orbit of the engaging piece of the oscillation plate after detecting the completion of the freezing operation.

Figure 34 shows a timing chart of the control to be effected by the cam control mechanism.

DESCRIPTION OF THE PREFERRED EMBODIMENTS

The cam control mechanism in the ice making machine according to this invention is described below by means of preferred embodiments with reference to the accompanying drawings.

(General composition of ice making machine)

Figures 7 and 8 schematically show, in a cross-section and a perspective view, the overall structure of the ice making machine using the cam control mechanism according to a first embodiment of the invention. A rectangular casing 10 constituting the main body of the ice making machine has therein a lower machine chamber 14 in which the freezing system including a compressor CM and a condenser 18 are housed, an ice box 12 which can be closed by a door 26 provided above the lower machine chamber 14 which is surrounded by a heat insulating material, and a freezing unit 20 which provided in the ice box 12 at an upper position thereof. As will be described later with reference to Figures 4 and 5, the freezing unit 20 comprises a water trough 24 in which a predetermined level of water to be frozen is supported, and a freezing base plate 34 having freezing fingers 36 to be immersed in the water to be frozen, the water trough 24 being inclined to a predetermined angle after switching the ice releasing operation for discharging the water remaining therein to the outside of the machine through a water collecting portion 28 and a drain pipe 30 as well as releasing the ice pieces into the ice box 12.

(freezing unit)

Figure 5 shows a detailed vertical sectional view of the freezing unit 20 in which the water trough 24, the structure of which is shown in Figures 4 and 6, supports a predetermined level of water to be frozen in the freezing chamber 32 defined therein. In other words, the freezing chamber 32 is defined by a rectangular bottom 24a of the water trough 24 and four walls 24b, 24c, 24d, 24e standing upright from the four respective sides of the rectangular bottom 24a. A pair of support members 24b are attached to the outer surfaces of the shorter walls 24d, 24e which face each other. As shown in Fig. 6, the support member 50 fixed to the wall 24d has a cam portion 50a which bends diagonally downward at a position outside the water trough 24, and a cam slot 54 is defined in the cam portion 50a into which a cam follower 56 eccentrically formed on a cam disk 58 (to be described later) is slidably fitted. A tongue 49 having a through hole is formed adjacent to the corner of the bent portion of each support member 50 at a position outside the water trough 24, and a pivot shaft 52 is inserted into these through holes. The pivot shaft 52 is fixed to the main body of the ice making machine so that the water trough 24 can be tilted downward or to the horizontal position. can be reset on the pivot shaft 52 under the cam action with the rotation of an actuator AM connected to the cam disc 58, as shown in Figures 13 to 15.

(freezing system)

Figure 9 shows a schematic composition of the freezing system to be used in the ice making machine. The refrigerant evaporated under compression by the compressor CM is sent through a delivery pipe 33, liquefied by the condenser 18 and, after drying in a dryer 35, decompressed through a capillary 37. The refrigerant thus treated then flows into an evaporator 22 where it can suddenly expand so that heat exchange is carried out with the freezing base plate 34 and the freezing fingers 36 are cooled below the freezing point. The part of the refrigerant evaporated in the evaporator 22 and the unevaporated part of the cooling medium flow into an accumulator 39 in the form of a gas-liquid mixture where they are separated into the respective phases. The gas phase of the refrigerant is circulated back to the compressor CM through an intake pipe 41, while the liquid phase of the refrigerant is collected in the accumulator 39. Furthermore, a hot gas pipe 43 branching from the delivery pipe 33 of the compressor CM is connected to the inlet side of the evaporator 22 through a hot gas valve HV. The hot gas valve HV is open during the ice releasing operation to bypass the heated medium (hereinafter referred to as hot gas) supplied from the compressor CM through the evaporator 22 via the hot gas pipe 43 to heat the freezing fingers 36 and allow the ice pieces to fall down by their own weight. Furthermore, the hot gas supplied from the evaporator 22 heats the liquid phase of the refrigerant residing in the accumulator 39 to evaporate it, and thus the evaporated refrigerant is circulated back to the compressor CM through the suction pipe 41. Incidentally, reference symbol FM denotes a fan motor for the condenser 18.

(Water trough water dispensing mechanism)

As shown in Figures 5 and 6, the water trough 24 has a drain for discharging the water remaining in the freezing chamber 32 whenever the water trough 24 is inclined. More specifically, a water gutter 38 is integrally formed at the bottom of the water trough 24 so as to extend diagonally downward therefrom, and a water collecting portion 28 for discharging the water thus collected to the outside of the machine is defined in the ice box 12 at an upper portion (see Figure 7). As shown in Figure 5, the one longer wall on the free end side of the water trough 24 (located opposite to the pivot shaft 52) constitutes a dam plate 42, and an inner wall 24c covering the dam plate 42 is integrally formed with the water trough 24. Incidentally, the lower free end of the inner wall 24c is disposed adjacent to the bottom of the water trough 24 with a very small gap therebetween. Consequently, as shown in Figure 5, the water to be frozen flows through the lower free end of the inner wall 24c to the dam plate 42, and then further flows over the dam plate 42 so that it is discharged to the water trough 38. In other words, the water to be frozen to be carried in the freezing chamber 32 can be held from a predetermined level by the dam plate 42.

After switching the ice releasing operation (to be described later), the water trough 24 is inclined downward as shown in Figure 13 to discharge the water remaining therein through the water trough 38. When the water trough 24 is stopped in the inclined position, a part of the freezing water is held by the dam plate 42 to remain therein (see Figure 14). The remaining water is combined with another part of the water to be frozen which is freshly supplied from a water supply pipe 68, thus effectively cooling the temperature of the water to be frozen as a whole.

The freezing base plate 34 is horizontally fixed to an upper position of the rectangular housing 10, and the evaporator 22 which is led out of the freezing system and accommodated in the machine chamber 14 is provided in a zigzag shape on the upper surface of the freezing base plate 34. Further, a plurality of freezing fingers 36 project downward from the lower surface of the freezing base plate 34 at predetermined intervals, and these freezing fingers 36 are designed to be immersed in the water to be frozen carried in the water trough 24 during the freezing operation. As the heat exchange with the refrigerant in the evaporator 22 progresses by the operation of the freezing system, the freezing fingers 36 are cooled and maintained at a temperature of 0°C or lower so that ice pieces 70 can gradually grow around the freezing fingers 36 as shown in Figure 12.

(Cam control mechanism)

As shown in Figure 1, a first cam 13, a second cam 15 and a third cam 17 are provided coaxially with the rotary shaft 11 of the actuating motor AM at predetermined intervals. Furthermore, a first switch SW₁, a second switch SW₂ and a third switch SW₃ are fixed to the main body of the ice making machine, and the cam actions are added to the rotation of the actuating motor AM so as to control the following movements to be caused by the operation of the actuating motor AM:

(1) tilting or resetting the water trough 24 and stopping it at such positions;

(2) Opening and closing the hot gas valve HV; and

(3) Opening and closing the water valve WV to supply water to be frozen.

More specifically, the first cam 13 takes a shape of a disk having a predetermined diameter with a pair of recesses 13a, 13b formed on its periphery, and the roller of a lever 19 extending from the first switch SW₁ abuts against the periphery of the first cam 13 and comes into engagement with the recess 13a or 13b according to a predetermined timing. These recesses 13a, 13b are not symmetrical on either side of the center of the cam at 180° angles. but with a predetermined central angle therebetween as shown in Fig. 1. Assuming that the peripheral portion formed between the recesses 13a, 13b with a larger central angle is denoted as A₁, while the peripheral portion formed therebetween with the smaller central angle is denoted as A₂, the peripheral portion A₁ assumes the cam surface for controlling the inclination of the water trough 24, and the peripheral portion A₂ assumes the cam surface for controlling the resetting of the water trough 24 to the horizontal position as will be described later. The first switch SW₁ is connected to a first relay X₁ in the control circuit shown in Fig. 2 for controlling the inclination and resetting of the water trough 24 and the stopping thereof at such positions. The timing of the cam operations between the first cam 13 and the first switch SW₁ as shown in the timing diagram of Figure 3.

The second cam 15, which also takes the form of a disk, has a peripheral portion with a central angle of about 270°, and the roller of a lever 21 extending from the second switch SW₂ abuts against the periphery of the cam 15 and engages the recess with a central angle of about 90° according to a predetermined time. The second switch SW₂ is connected to a second relay X₂ as shown in Figure 2, and controls the opening and closing of the hot gas valve HV in cooperation with the opening and closing of a normally open contact X₂-a (as will be described later). The third cam 17 has a peripheral cam surface with a predetermined central angle, and the roller of a lever 23 extending from the third switch SW₃ abuts against the periphery of the third cam 17. The third switch SW₃ is switched on when the lever 23 of the third switch hits the cam surface. The third switch SW₃ is connected to a third relay X₃ as shown in Figure 2 and controls the opening and closing of the water valve WV in interlock with a normally open contact X₃-a₁ (as will be described later). The timing of the cam operations between the second cam 15 and the second switch SW₂ and that between the third cam 17 and the third switch SW₃ is shown in the timing chart of Figure 3.

(vibrating plate)

An L-shaped swing plate 44 is provided in the freezing chamber 32 defined in the water tub 24 so that it can swing freely therein by the rotation of the swing motor RM. More specifically, the swing plate 44 is a planar plate having a vertical portion 45 and also a plurality of through holes 46 defined therein at predetermined intervals as shown in Figure 6. The peripheral size of the swing plate 44 is slightly smaller than the inner peripheral size of the bottom 24a of the freezing chamber 32, and the upper end portion of the vertical portion 45 is rolled outward to form through holes on each side into which a swing shaft 48 is inserted. The end portions of the swing shaft 48 are inserted into the through holes 53a of the tongues 53 formed on the outer surfaces of the side walls of the water tub 24. When the swing plate 44 is swingably supported by the swing shaft 48, the swing plate 44 is brought into close contact with the bottom of the freezing chamber 32, as shown in Figure 5.

As shown in Fig. 6, the swing plate 44 also has a vertical tongue 59 formed thereon on a shorter edge thereof, and an engagement pin 61 extends horizontally outward therefrom. Furthermore, as shown in Figs. 4 and 6, the swing motor RM is provided on the inner wall surface of the main body of the ice making machine in such a manner that it can be easily displaced vertically as will be described later. An engagement piece 62 projecting from the rotary shaft of the motor RM can be engaged with the engagement pin 61 of the swing plate 44 disposed above the engagement pin 62. Consequently, by rotating of the swing motor RM counterclockwise, the engaging piece 62 is rotated in engagement with the engaging pin 61 to raise the swing plate 44 from the bottom of the freezing chamber 32 to a predetermined height as shown in Figure 10, and then it is allowed to fall to the bottom of the freezing chamber 32 by its own weight due to the disengagement of the engaging piece 62 from the engaging pin 61 as shown in Figure 11. Namely, the swing plate 44 repeats such swinging motion in the freezing chamber 32 on the swing shaft 48 by rotating the swing motor RM during the freezing operation, whereby the water to be frozen can be constantly stirred. Besides, since the swing plate 44 has through holes 46, the water to be frozen flows up and down through these through holes 46, whereby the stirring of the water to be frozen can be further accelerated. However, these through holes 46 are not inevitable, but may be omitted as desired. Further, while the swing plate 44 can be inclined when the water trough 24 is inclined before the ice releasing operation (to be described later) is started, a stopper 63 extending horizontally from the rectangular casing 10 is provided in the inclination orbit of the engaging pin 61 provided on the swing plate 44. By allowing the engaging pin 61 to engage with the stopper 63 during the operation of inclining the swing plate 44 together with the water trough 24, the swing plate 44 is separated from the water trough 24 and takes a predetermined inclined position there.

(Switch SW4 for detecting the completion of ice formation and Switch Th for detecting the completion of ice release operation)

As shown in Figures 4 and 5, the swing motor RM is provided so as to be easily vertically displaceable via mounts 25 provided on the inner wall surface of the main body of the ice making machine and normally located at the uppermost position. After installation a predetermined external force on the motor RM, the motor RM can be displaced downward by a predetermined stroke. Further, the lever 27 of a switch SW₄, such as a microswitch for detecting the completion of ice formation, is arranged in the descending orbit of the motor RM so that it can abut against the swing motor RM as it descends, so that the switch SW₄ is turned on. Namely, as will be described later with reference to Fig. 12, when ice pieces 70 are formed around the freezing fingers 36 as the freezing process proceeds, the swing plate 44 is brought into contact with these ice pieces 70 on its upward stroke, so that a downward counterforce is exerted on the swing motor RM through the engaging pin 61 and the engaging piece 62. Consequently, the swing motor RM starts to descend from the uppermost position so that it depresses the lever 27 of the switch SW₄ as it descends, thereby turning the switch SW₄ on. is turned on, and thus the completion of the ice formation in the freezing unit 20 is detected. Furthermore, as shown in Figs. 4 and 5, a thermometal switch Th for detecting the completion of the ice releasing operation is provided on the upper surface of the freezing base plate 34 in the freezing unit 20, which is turned on by the sudden temperature rise caused by the falling of the ice pieces 70 from the freezing chambers 36, thereby rotating the actuating motor AM.

(Example of an electrical control circuit)

Figure 2 shows an electric control circuit in the ice making machine according to the first embodiment of the invention, in which a fuse F and a switch SW₅ for detecting ice fullness are connected in series between a power supply line R and a connection D, and a compressor CM is connected between the connection D and a line T. Accordingly, (1) a first switch SW₁ for the actuating motor AM shown in Figure 1 and a relay X₁; (2) a second switch SW₂ for supplying hot gas shown in Figure 1 and a second Relay X₂; (3) a third switch SW₃ for supplying water to be frozen shown in Fig. 1 and a relay X₃; and (4) a switch SW₄ for detecting the completion of ice formation shown in Fig. 4 and a relay X₄ are connected in series between the connection D and the line T, respectively. Furthermore, a timer for controlling the time of driving the swing motor RM is also interposed, one terminal of which is connected to the line T while the other terminal is connected to the connection D through a normally open contact X₃-a₂ of the relay X₃. Incidentally, a second normally open contact Ta₂ for the timer is connected in parallel to the normally open contact X₃-a₂ for achieving self-holding thereof.

One terminal of the operating mode AM is connected to the line T, while the other terminal thereof is connected to the connection D through the elements connected in parallel: (1) a normally open contact X4-a for the relay X4; (2) a contact X1-a for the relay X1; and (3) the thermometallic switch Th for detecting the termination of the ice release operation. Between the connection D and the line T are also connected in series respectively (1) the oscillating motor RM and a first normally open contact T-a1 for the timer; (2) the hot gas valve HV and the contact X2-a for the second relay X2; and (3) the water valve WV for supplying water to be frozen and the normally open contact X3-a1 for the relay X3.

Next, the operations of the cam control mechanism according to the first embodiment of the invention will be described with reference to the timing chart shown in Fig. 3. Before the freezing operation is started, the water tub 24 is held in a horizontal position as shown in Fig. 5, and the water to be frozen is supplied to the freezing chamber 32 defined in the water tub 24 through the water supply pipe 68. The supply and stopping of the water from the water supply valve 68 is carried out by controlling the opening and closing of the water valve WV by the cam action between the third cam 17 and the third switch SW₃. Even if an excess amount of water should be supplied to the freezing chamber 32, the excess part of the water flows over the dam plate 42 and is discharged to the outside of the machine through the water gutter 38 and the water collecting section 28 as described above.

A coolant is supplied to the evaporator 22 from the circulation pipe of the freezing system, and cooling of the freezing fingers 36 formed on the freezing base plate 34 is started by the heat exchange action of the coolant. Since the freezing fingers 36 are immersed in the water to be frozen, the water around the freezing fingers 36 starts to freeze and gradually grows into inverted dome-shaped ice pieces 70 as shown in Figure 12. During such freezing action, the swing motor RM is continuously rotated with the rotation time thereof set by the timer. Consequently, the engaging piece 62 provided on the rotary shaft of the motor RM is engaged with the engaging pin 61 provided on the vertical tongue 59 so that the swing plate 44 is raised as shown in Figure 10. After the engagement piece 62 is released from the engagement pin 61, the swing plate 44 falls by its own weight and abuts against the bottom 24a of the freezing chamber 32 as shown in Fig. 11. Thus, the swing plate 44 repeats such swinging motion in the water to be frozen in the freezing chamber 32 during the freezing operation to constantly stir the water. Furthermore, since through holes 46 are formed in the swing plate 44, the water to be frozen flows through these through holes 46 while the swing plate 44 is being swung, thereby causing jet currents which further accelerate the stirring of the water to be frozen. Since the water to be frozen is constantly kept in a dynamic state as described above, the clouding into white around the freezing fingers 36 to form ice pieces can be prevented, and transparent and clear ice pieces 70 can be obtained.

As shown in Figure 12, after the formation of the inverted dome-like ice pieces 70 completely around the freezing fingers 36, the oscillating plate 44 is brought into contact with the ice pieces 70 in its upward stroke and finally exerts a downward counterforce to the oscillating motor RM through the engaging pin 61 and the engaging piece 62.

Consequently, the swing motor RM starts to move down from the uppermost position so that it depresses the lever 27 of the frost-finishing detection switch SW4 to turn on the switch SW4, and thus the frost-finishing detection in the freezing unit 20 is detected. Whereupon the relay X4 shown in Figure 2 is actuated to close the normally open contact X4-a interlocked therewith and to start rotating the actuating motor AM. Thus, the cam disc 58 is rotated clockwise to allow the cam follower 56 eccentrically provided to slide along the cam slot 54 formed on the cam 50a, and thus the water tray 24 starts to incline downward. By this inclining movement of the water trough 24, the water remaining in the freezing chamber 32 flows along the inner wall 24c and over the dam plate 42 to the water gutter 38 and in turn to the water collecting section 28. Incidentally, while the lever 19 of the first switch SW₁ shown in Figure 1 is engaged with the recess 13a of the first cam immediately before the actuating motor AM is rotated, the lever 19 rides on the peripheral section A₁ when the motor AM is started to turn on the switch SW₁. Thus, the relay X₁ is operated to close the normally open contact X₁-a, which is thereby locked. Consequently, the counterforce exerted on the swing motor RM is cancelled by the inclination of the water trough 24, and the rotation of the actuating motor AM is continued by closing the normally open contact X₁-a even after the ice formation completion detection switch SW₄ is turned off.

After the engagement of the lever 19 with the recess 13b of the first cam 13, the switch SW₁ is turned off to release the activation of the relay X₁ and to open the normally open contact X₁-a interlocked therewith. Consequently, the water trough 24 stops at a predetermined angle as shown in Figure 14. In this state, while a part of the water to be frozen remains in the freezing chamber 32 due to the presence of the dam plate 42, such remaining water, which is fully cooled during the previous freezing operation, is mixed with another part of water, which is freshly supplied, so that the thus combined water to be frozen is effectively cooled. Furthermore, the ice pieces 70 formed around the freezing fingers 36 are exposed by thus inclining the water trough 24. Further, since the swing plate 44 is also inclined when the water tub 24 is inclined, the engaging pin 61 is released from the engaging piece 62 of the swing motor RM. In the process of stopping the water tub 24 in the inclined position, the engaging pin 61 of the swing plate 44 is engaged with the stop 63 as shown in Figure 14, so that the swing plate 44 can be arranged diagonally above the bottom 24a of the freezing chamber 32 in the water tub 24 which later stops in the inclined position. The swing plate 44 also serves as a groove for guiding the ice pieces 70 falling off the freezing fingers 36 into the ice box 12.

In the operation of tilting the water tray 24, the lever 21 of the second switch SW₂ engages the recessed peripheral portion (having a central angle of about 90°) of the second cam 15 to turn on the switch SW₂ and activate the second relay X₂ shown in Fig. 2. Whereupon the normally open contact X₂-a interlocked with the relay X₂ is closed to open the hot gas valve HV and supply hot gas instead of the refrigerant to the evaporator 22 according to the timing chart shown in Fig. 3. Thus, the freezing fingers 36 are rapidly heated by the freezing base plate 34. Consequently, the connection between the freezing fingers 36 and the ice pieces 70 is released, and the ice pieces 70 fall by their own weight, slide on the upper surface of the swing plate 44 held at a predetermined inclined position by the stopper 63, and are guided into the ice box 12 disposed thereunder.

The negative temperature load exerted on the freezer base plate 34 is canceled by the falling off of the ice pieces 70, and the temperature of the freezer base plate 34 is suddenly increased by the passage of the hot gas through the evaporator 22. This temperature rise is detected by the thermometal switch Th which is thereby turned on so that the actuating motor resumes its rotation. Consequently, the cam portion 50a is rotated counterclockwise on the pivot shaft 52 under the cam action of the cam disc 58, the cam follower 56 and the cam slot 54, thereby allowing the water trough 24 to rotate counterclockwise and begin to return to the horizontal position. When the motor AM resumes rotation, the second cam 15 resumes rotation, thereby causing the lever 21 extending from the second switch SW₂ to rotate counterclockwise. can ride on the peripheral cam surface of the second cam 15 and turn off the switch SW₂. Thus, the activation of the second relay X₂ shown in Figure 2 is cancelled so that the normally open contact X₂-a is opened which is interlocked therewith and the hot gas valve HV is closed. Consequently, the supply of the refrigerant to the evaporator 22 is restarted. Further, when the motor AM resumes rotation, the lever 23 of the third switch SW₃ is engaged with the peripheral cam surface of the third cam 17 to turn on the switch SW₃, thereby activating the third relay X₃ shown in Figure 2 to close the normally open contact X₃-a₁ which is interlocked therewith and open the water valve WV to supply too freezing water to the freezing chamber 32. After the third cam 17 disengages from the third switch SW₃, the switch SW₃ is turned off to cancel the activation of the third relay X₃ for opening the normally open contact X₃-a₁ as well as closing the water valve WV and stopping the supply of the water to be frozen.

Furthermore, upon rotation of the operating mode AM, the lever 19 of the first switch SW₁ engaged with the recess 13b of the first cam 13 rides on the cam surface of the peripheral portion A₂ to activate the relay X₁ and open the normally open contact X₁-a, thereby energizing the motor AM in cooperation with the thermometal switch Th which is closed immediately after the cooling of the freezing base plate 34 is resumed by supplying the coolant to the evaporator 22 as described above. After the engagement of the lever 19 of the first switch SW₁ in the recess 13a while the first cam 13 is rotated, the switch SW₁ is opened to cancel the activation of the relay X₁ and to open the normally open contact X₁-a. Thus, the rotation of the actuating motor AM is stopped, to allow the water trough 24 to stop in the horizontal position.

Besides, when the third switch SW₃ is turned on to open the water valve WV, the normally open contact X₃-a₂ interlocked with the relay X3 energizes the timer . After the lapse of a predetermined period of time set in the timer, the first normally open contact Ta₁ interlocked therewith is closed to start the rotation of the swing motor RM so that the swing plate 44 resumes its swinging motion during the freezing operation. Further, the second normally open contact Ta₂ of the timer is closed to cause the timer to hold. After the lapse of the preset period of time in the timer , the first and second normally open contacts Ta₁ and Ta₂ are closed to stop the rotation. of the oscillating motor RM opened.

(Schematic composition of the ice making machine according to the second embodiment)

Figures 17 and 23 schematically show, in a cross-sectional view and a perspective view, respectively, the overall structure of the ice making machine in which the cam control mechanism according to a second embodiment of the invention is used. For the sake of simplicity, it should be understood that the terms "front", "rear", "right" and "left" referred to here refer to the front view of the ice making machine. A rectangular casing 110 constituting the main body of the ice making machine basically has defined therein a lower machine chamber 112 in which a freezing system including a compressor CM and a condenser 111 are housed, a box-like ice box 114 provided above the lower machine chamber 112, surrounded with a heat insulating material and having defined therein an ice chamber 183, and a freezing unit 115 provided in the ice box 114 at an upper position thereof. As will be described later with reference to Figs. 18 and 19, the freezing unit 115 has a water trough 116 in which a predetermined level of water to be frozen is supported, and a freezing base plate 118 having freezing fingers 117 to be immersed in the water to be frozen, the water trough 116 being inclined to a predetermined angle after switching the ice releasing operation for discharging the water remaining in the water trough 116 to the outside of the machine through a water collecting portion 119 and a drain pipe 120 as well as for releasing the ice pieces 121 into the ice chamber 183. Incidentally, an ice discharging mechanism 113 (to be described later) is provided on the ice box 114, and the ice pieces 121 stored in the ice chamber 183 can thereby be discharged to the outside of the machine .

(External structure of the rectangular housing)

As shown in Figure 23, the rectangular casing 110 is composed of a main frame 122 which surrounds all the above-described parts and a front plate 123 which is provided on the front surface of the main frame 122 and as a whole assumes a slender body with a very narrow transverse dimension. The front plate 123 is made of a synthetic resin and formed into the shape as shown in Figure 23, in which a downward opening 123a for discharging the ice pieces 121 contained in the ice box 114 is formed at half the height thereof in alignment with the outlet 114a (see Figure 17). A hollow table 124 is removably inserted into the space below the opening 123a on which a vessel such as a glass can be placed whenever ice pieces 121 are to be supplied. This table has on the upper surface thereof a plurality of slits 124a for draining water drops dripping from the outlet 114a and the opening 123a to collect them therein so as to prevent the splashing of water drops around the machine. The front panel 123 also has a power supply indicator lamp L and a push button 125 for the sixth switch SW₆ for dispensing the ice pieces 121 stored in the ice chamber 183 provided in the upper part thereof extending over the opening 123a, and the ice dispensing unit 113 is operated to dispense the ice pieces 121 stored in the ice chamber 183 through the outlet 114a and the opening 123a only when the push button 125 is depressed to turn on the sixth switch SW₆.

An opening (not shown) is defined in the bottom of the rectangular casing 110 so as to communicate with the machine chamber 112. The opening is removably covered by a filter 126. The filter 126 serves to collect dust in the external air introduced into the machine chamber 112 for cooling the condenser 111, thereby preventing the reduction in the cooling capacity thereof which would be caused by clogging of the condenser. Incidentally, the filter 126 is also such that it can be easily pulled out from the front side of the rectangular casing 110. Housing 110 can be pulled out.

(Inner cover)

As shown in Figure 17, an inner cover 127 is removably mounted on the front of the ice box 114, on which the actuating motor AM for inclining the water tray 116 in the freezing unit 115, the swinging motor RM for swinging a swinging plate 154 (to be described later), and a dispensing motor GM for the ice dispensing unit 113 are all mounted on the front surface thereof. Consequently, the respective motors AM, RM, GM and the associated parts can all be exposed by removing the front panel 123, whereby maintenance and repair thereof can be facilitated. Furthermore, the inner cover 127 with the motors AM, RM, GM already mounted thereon can be inserted on the front of the ice box 114, which advantageously leads to a reduction in the time required for assembling the automatic ice making machine.

(freezing unit)

Figure 19 shows a detailed vertical sectional view of the freezing unit 115, and the water trough 116, the structure of which is as shown in Figure 18, can accommodate a predetermined level of water to be frozen in the freezing chamber 129 defined therein. In other words, the freezing chamber 129 is defined by a rectangular bottom 116a of the water trough 116 and four walls 116b, 116c, 116d, 116e standing upright from the respective sides of the rectangular bottom 116a. A plurality of pins 130 are formed on the outer surface of the right wall 116e in Figure 18 and are aligned horizontally. These pins 130 are pivotally inserted into the through holes 132a defined in the brackets 132 which hold the freezing base plate 118 at the upper position in the ice box 114 so that the water tray 116 can be pivoted sideways onto the pins 130 (see Figure 21). Incidentally, a water supply pipe 149 for supplying water to be frozen is removably attached to the freezing base plate 118 at a appropriate position (to be described later) which is designed to supply a predetermined amount of water to be frozen to the freezing chamber 129 by opening the water valve WV according to the timing to be described later (see Figure 34). Advantageously, since the freezing unit 115 can be easily separated from the supports 132 by removing the inner cover 127 from the ice box 117, the assembly or maintenance and repair of the ice making machine can be facilitated.

Further, a square hole 130a is defined in the frontmost pin 130, into which a square shaft 133a is inserted, which projects from the free end of a pivot shaft 133 (to be described later). The pivot shaft 133 is pivotally supported on the inner cover 127, and thus the water trough 116 can be tilted downward on the pin 130 and reset upward with rotation of the actuating motor AM mounted on the inner cover 127, as shown in Figures 29 to 32. Such composition of the water trough 116 tilted sideways can reduce the width of the ice making machine. Besides, since the pins 130 are formed integrally with the water trough 116 so that the water trough 116 can be inclined or retreated by rotating the pins 130, not only the rigidity of the water trough itself can be increased, but also the inclination and retreat of the water trough 116 can be smoothly performed. Furthermore, the pins are formed horizontally along the longitudinal direction of the water trough 116 so that the load of the water trough 116 can be evenly applied to the pins so that the water trough 116 can be maintained in the horizontal position without inclination in the longitudinal direction thereof.

(Water trough tilt mechanism)

A cylindrical bearing 134 projecting forward is provided on the inner cover 127 at a position corresponding to the location of the pins 130 of the water trough 116, and the pivot shaft 133 is pivotally supported in the through hole 134, defined in the bearing 134. The square shaft 133a formed on the other end of the pivot shaft 133 is inserted into the square hole 130a of the pin 130. A lever 133b is formed integrally with the pivot shaft 133 so as to extend radially from the front end portion thereof, and a projection 133c is formed on the front surface of the lever 133b at the free end portion thereof. As shown in Figs. 16 and 18, a cam plate 136 which is a disk having a predetermined diameter and having a notch on the circumference thereof is provided on the rotary shaft of the actuating motor AM mounted on the inner cover 127 through a bracket 135 while projecting through the bracket 135. A connecting rod 137 is pivotally eccentrically supported at one end portion thereof on the front surface of the cam plate 136, and the other end portion of the connecting rod 137 has a slot 137a into which the projection 133c of the lever 133b formed integrally with the pivot shaft 133 is slidably engaged. Consequently, the pivot shaft 133 can be pivoted back and forth within a predetermined angular range by the cam plate 136 and the connecting rod 137 by the rotation of the operating motor AM, thereby tilting the water trough 116. Incidentally, since the operating motor AM is provided for pivoting the pins 130 on which the water trough 116 is tilted, it can be of low output.

The water tray 116 maintains a horizontal position with the engaging projection 133c of the lever 113b abutting against the lower end (the side facing the supporting portion of the cam plate 136) of the slot 137a in the connecting rod 137 (see Figure 20). Further, an elliptical regulating piece 133d which can be inserted through the slot 137a of the connecting rod 137 is provided at the front end of the projection 133c, and this regulating piece 133d is elongated in the radial direction of the projection 133c so that the connecting rod 137 cannot easily come off the projection 133c with the engagement of the projection 133c with the slot 137a. Further the lever 133b is slidable within the allowable range of the slot 137a relative to the connecting rod 137 so as to tolerate any errors in the positions of the lever 133b and the connecting rod 137 when the water trough 116 is stopped in the inclined position. Incidentally, an engaging piece 133e is formed on the rear side of the lever 133b, with which one end of a torsion spring 139 (to be described later) urges a mount 138 (to be described later) on which the swing motor RM is mounted in a predetermined direction.

(Water trough water dispensing mechanism)

As shown in Figs. 19 and 24, the water trough 116 has a drain for discharging the water remaining in the freezing chamber 129 whenever the water trough 116 is inclined. More specifically, an auxiliary chamber 146 is defined on the back of the rear wall 116c of the water trough 116 at the end portion which can assume the lowermost position when the water trough 116 is inclined, and a pipe 147 having a predetermined length is connected to the outer (rear) wall surface of the auxiliary chamber 146. The water collecting portion 119 for discharging the water thus collected to the outside of the machine, which is defined on the back of the ice box 114, is arranged below the pipe 147. The auxiliary chamber 146 and the freezing chamber 129 are delimited by a dam plate 148 which is lower than the wall 116c. Consequently, the water to be frozen supplied to the water trough 116 flows over the upper end of the dam plate 148 and is discharged to the water collecting section 119 through the pipe 147. In other words, the water to be frozen to be carried in the freezing chamber 129 can be held up to a predetermined level by this dam plate 148. After switching to an ice releasing operation, the water trough 116 is inclined downward to discharge the water remaining therein through the pipe 147 as shown in Figure 24. When the water trough 116 stops in this inclined position, a part of the water to be frozen still remains therein due to the presence of the dam plate 148 (see Figure 30), and combined with the water freshly supplied from the water supply pipe 149 for the next cycle of freezing action, it accelerates the cooling of the water to be frozen.

Incidentally, the pipe 147 also serves as a stopper for the water trough 116 which abuts against the upper edge defining the water collecting section 119 and the ice box when the water trough 116 is tilted downward. Since the projection 133c of the pivot shaft 133 is slidable in the slot 137a of the connecting rod 137 in the tilt mechanism, any load acting on the tilt mechanism caused by the displacement between the stop position of the tilted water trough 116 and the stop position of the actuating motor AM can be avoided.

The freezing base plate 118 is horizontally supported at an upper position of the ice box 114 by a plurality of supports 132, and an evaporator 131 led out from the freezing system housed in the machine chamber 112 is provided in a zigzag shape on the upper surface of the freezing base plate 118. Further, a plurality of freezing fingers 117 project downward from the lower surface of the freezing base plate 118, and these freezing fingers 117 can be immersed in the water to be frozen carried in the water trough 116 during the freezing operation. When the heat exchange with the refrigerant in the evaporator 131 progresses by operating the freezing system, the freezing fingers 117 are cooled and maintained at a temperature of 0°C or lower so that ice pieces 121 can gradually grow around the freezing fingers 117 as shown in Figure 27. Incidentally, the freezing base plate 118 has a plurality of through holes 118a so that the heat exchange efficiency as well as the contribution to weight reduction of the ice making machine are improved.

(Cam control mechanism)

As shown in Figure 20, a first cam 150 and a second cam 151 are formed on the rear surface of the cam plate 136 provided on the actuating motor AM at radially offset positions. Furthermore, a seventh switch SW7 and a ninth switch SW9 are provided on the carrier 135 at the positions corresponding to the locations of the first cam 150 and the second cam 151. By the cam actions added to the rotation of the actuating motor AM according to a predetermined time, the following movements to be caused by the operation of the actuating motor AM are controlled:

(1) Tilting or resetting the water trough 116 and stopping it at such positions, as well as opening the hot gas valve HV; and

(2) Opening and closing the water valve WV for supplying water to be frozen. More specifically, the first cam 150 and the second cam 151 each take a shape of an arcuate rib with a predetermined radius protruding in the axial direction, and a lever 152 extending from the seventh switch SW₇ abuts against the first cam 150 or is at a distance therefrom at a predetermined time. The seventh switch SW₇ is turned on after the contact of the lever 152 of the seventh switch SW₇ with the first cam 150. The seventh switch SW₇ is connected to a relay X₂. and the actuating motor AM as shown in the control diagram of Figure 25, and it controls the inclination and resetting of the water trough 116 as well as its stopping at such positions by the actuating motor AM and also the opening of the hot gas valve HV as will be described later. Incidentally, the timing of actuation of the seventh switch SW₇ by the first cam 150 is shown in the timing chart of Figure 34.

Further, the lever 153 extending from the ninth switch SW₄ is brought into contact with the second cam 151 or at a distance therefrom according to a predetermined time. The ninth switch SW₉ is turned on upon the contact of the lever 153 thereof with the second cam 151. As shown in Fig. 25, the ninth switch SW₉ is connected to the water valve WV for controlling the opening thereof (as will be described later). The timing of the cam actions to be effected by the second cam 151 and the ninth switch SW₉ is shown in the timing chart of Fig. 34.

(Swing plate and swing mechanism)

A swing plate 154 is provided in the freezing chamber 129 defined in the water trough 116 in such a manner that it can swing freely therein. The swing plate 154 has a rectangular bottom plate 154a and side walls 154b, 154c, 154d standing upright from the three side edges of the bottom plate 154a except the side edge opposite the left wall 116d which is to assume the lowermost position when the water trough 116 is inclined, and is swung by the rotation of the swing motor RM. A plurality of circular and/or square through holes are formed at predetermined intervals in the bottom plate 154a and the right side wall 154b of the swing plate 154. The circumferential dimension of the swing plate 154 is designed to be slightly smaller than the inner circumferential size of the bottom plate 116a of the freezing chamber 129, and a pair of outer projections 156 formed on each long side of the side wall 154b are pivotally supported in the water trough 116 by a pair of pins 157. When the swing plate 154 is pivotally supported in the water trough 116, the swing plate 154 is brought into close contact with the bottom of the freezing chamber 129, as shown in Figure 19. Incidentally, the positions of the through holes 155 formed in the bottom plate 154a are arranged between every two adjacent freezing fingers 117.

As shown in Figure 16, an inverted L-shaped engaging piece 158 is formed on the front side wall 154c of the swing plate 154, and its upper horizontal portion 158a extends outside the wall 116b of the freezing chamber 129. Further, a vertically elongated opening 127a is defined in the inner cover 127 at a position corresponding to the location of the upper horizontal portion 158a, into which a vibrating member 159 rotated by the vibrating motor RM is slidably inserted. A vibrating projection 159a is eccentrically formed on the back of the vibrating member 159 which can come into engagement with the lower surface of the upper horizontal portion 158a of the vibrating plate 154 on the back of the inner cover 127. Consequently, the swing projection 159a is rotated and engaged with the upper horizontal portion 158a by rotating the swing member 159 counterclockwise to raise the swing plate 154 to a predetermined height from the bottom of the freezing chamber 129 as shown in Figure 26, whereupon upon the release of the swing projection 159a from the upper horizontal surface 158a, the swing plate 154 is allowed to fall to the bottom of the freezing chamber 129 by its own weight. Namely, by the rotation of the swing motor RM during the freezing operation, the swing plate 154 repeats such a swinging motion in the freezing chamber 129 on the pin 157, whereby water to be frozen can be constantly stirred.

Besides, since the vibrating plate has the through holes 155, the water to be frozen flows up and down through these through holes 155, whereby the stirring of the water to be frozen can be further accelerated.

While the swing plate 154 is tilted when the water trough 116 is tilted after switching to the ice releasing operation to be described later, a vertical part 160 extending upward above the height of the freezing base plate 118 is formed on the upper edge of the right side wall 154b of the swing plate 154. By allowing the vertical part 160 to engage with the freezing base plate 118 on the way in which the swing plate 154 is tilted together with the water trough 116, the swing plate 154 can be separated from the water trough 116 and assume a fixed inclined position as such (see Figure 30).

(Fitting structure of the RM oscillating motor)

As shown in Figs. 16 and 20, an end portion of the planar mount 138 is pivotally fitted to the bearing 134 protruding from the inner cover 127, and the swing motor RM is provided on the front surface of the mount 138 at a position spaced from the pivotally fitted portion thereof. The swing motor RM is connected to the cam 149b protruding from the swing member 159 through the through hole 127a. Further, a vertical member 138a is formed on the front side of the mount 138 at a position between the pivotally fitted portion thereof and the swing motor RM, and an end portion 139a of the torsion spring 139 is engaged with the lower end of the vertical member 138a. The engaging piece 133e formed on the lever 133b is arranged adjacent to the vertical part 138a, and the other end portion 139b of the torsion spring 139 is engaged with the upper end of the engaging piece 133e. In the state where the water tray 116 is held in the horizontal position, the upper end of the engaging piece 133e extends above the upper end of the vertical part 138a of the mount 138, as shown in Figure 26. Consequently, in this state, the mount 138 is constantly urged to rotate clockwise on the bearing 134 under the resilient action of the torsion spring 139. Upon application of a predetermined external force to the swing motor RM, the mount 138 is pivoted by a predetermined angle on the bearing 134.

Namely, the torsion spring 139 serves to hold the swing projection 159a of the swing member 159 at the operating position where it can be engaged with the engaging piece 158 of the swing plate 154 while the water tray 116 assumes a horizontal position during the freezing operation. Furthermore, when the water tray 116 is moved after switching from the freezing operation to the ice releasing operation, the upper end of the engaging piece 133e of the lever 133b is displaced to a position lower than the upper end of the vertical part 138a of the mount 138, and the end portion 139b of the torsion spring 139 is engaged with the upper end of the vertical part 138a (see Figure 33). Consequently, the torsion spring 139 does not press the mount 138 while the water tray 116 is inclined.

Incidentally, a vertical slot 138b is defined in the mount 138 at the distal end at a distance from the pivoted portion thereof, and a regulating pin 161 provided on the inner cover 127 at the corresponding position is slidably inserted therein. The regulating pin 161 serves to regulate the pivoting range of the mount 138 so that the lower end of the slot 138b normally abuts against the regulating pin 161 under the resilient action of the torsion spring 139 so that the swing member 159 can be in the operating position (see Figure 29).

(Switch SW₁₀ for detecting the completion of ice formation and Switch Th₁ for detecting the completion of ice release operation)

A tenth switch SW₁₀ such as a microswitch for detecting the completion of ice formation is provided on the inner cover 127 through a bracket 170, the lever 162 of the switch SW₁₀ being arranged in the descending orbit of the cam 159b of the swing member 159 so that it can abut against the cam 159b when the mount 138 (swing motor RM) is pivoted and actuates the switch SW₁₀. Namely, as will be described later with reference to Fig. 27, when ice pieces 121 are formed around the freezing fingers 117 while the freezing operation is proceeding, the swing plate 154 is brought into contact with these ice pieces 121 during its upward stroke so that a downward counterforce is exerted on the swing motor RM through the engaging piece 158 and the swing projection 159a. Consequently, the fastening 138 on which the swing motor RM is mounted is pivoted counterclockwise on the bearing 134 and allows the cam 159b to depress the lever 162 of the tenth switch SW₁₀ during its pivoting operation so that the tenth switch SW₁₀ is changed from the contact "a" to the contact "b" and thus the completion of ice formation is detected. Incidentally, since the bracket 170 is provided on the inner cover 127 adjustably in the vertical direction, the position of the lever 162 of the tenth switch SW₁₀ can be adjusted by vertically adjusting the position of the bracket 170. Thus, the size of the ice pieces 121 to be formed around the freezing fingers 117 can be changed.

It should be noted here that when the swing motor RM is stopped after the tenth switch SW₁₀ is changed to the contact "b", the swing projection 159a abutting against the engaging piece 158 of the swing plate 154 interferes with the inclining movement of the swing plate 154. Therefore, in the second embodiment, a notch 159c is formed in the cam 159b of the swing member 159, which changes the tenth switch SW₁₀ to the contact "a" while the swing motor RM is swung downward, thereby controlling the swing projection 159a to avoid the swing orbit of the engaging piece 158. Furthermore, this notch 159c is defined on the cam 159b in a positional relationship such that it is located at a position corresponding to that of the lever 162 of the tenth switch SW₁ when the swing projection 159a is located at a distance from the upper horizontal distance 158a of the engaging piece 158. In other words, the motor RM is designed:

(1) that it is further rotated after the tenth switch SW₁₀ for detecting the completion of ice formation is changed to the contact "b" by swinging the swing motor RM; and

(2) that it is stopped when the notch 159c is brought into the position corresponding to the position of the lever 162 of the switch SW₁₀ for changing the switch SW₁₀ to the contact "a". Thus, the swing projection 159a avoids the inclination orbit of the engagement piece 158 of the oscillating plate 154 and does not collide with the inclination movement of the oscillating plate 154.

As shown in Figure 19, a thermometal switch Th₁ for detecting the completion of the ice releasing operation is provided on the upper surface of the freezing base plate 118 in the freezing unit 115. This thermometal switch Th₁ is changed to the contact "b" after the temperature of the freezing base plate 118 drops to a certain level by the freezing operation, or changed back from the contact "b" to the contact "a" after detecting the sudden temperature rise caused by the falling of the ice pieces 121 from the freezing fingers 117 by the ice releasing operation. At the same time, the hot gas valve HV is closed as will be described later, and the actuating motor AM is rotated.

(Ice dispenser and ice fullness detection switch)

An ice dispensing motor GM is provided at the front lower position of the inner cover 127, and a screw 163 for carrying the ice pieces to be driven by the motor GM is provided in the ice chamber 183 so as to extend therein. The inner end portion of the screw 163 is rotatably inserted into a recess 164 defined at the corresponding position of the ice box 114 as shown in Figure 17 so that the screw 163 can be rotated at a fixed position. The ice dispensing motor GM is rotated only while the push button 125 provided on the front panel 123 is pressed to operate the sixth switch SW6, and the ice pieces 121 stored in the ice chamber 183 are carried to the outlet 114a with the aid of the screw 163.

As shown in Figure 17, a regulating plate 165 is pivotally suspended from the rear side of the inner cover 127 at a position corresponding to the location of the screw 163 and further inside than the position of the outlet 114a. This regulating plate 165 is pushed forward by the ice pieces 121 which carried by the screw 163 so as to open the outlet 114a and enable the ice pieces 121 to be supplied to the outside of the machine, and also to return to the initial position when the ice dispensing unit 113 is stopped so as to close the outlet 114a and prevent outside air from flowing into the ice chamber 183. Furthermore, a separator 168 is provided on the inner cover 127 at a position adjacent to the regulating plate 165 for preventing the ice pieces 121 stored in the ice box 114 from slipping out of the outlet 114a as well as for preventing some of the ice pieces carried by the screw 163 from returning to the ice chamber 183 and for preventing the outlet 114a from being blocked thereby. Incidentally, a drain pipe 169 is provided at the bottom of the ice box 114 adjacent to the recess 164 so that the water melting from the ice pieces 121 can be discharged to the outside of the ice box 114.

A detecting plate 166 is pivotally supported on the lower surface of the water trough 116, which is normally maintained in such a state that the open end side thereof can be spaced downward from the bottom of the water trough 116. An eighth switch SW₆ for detecting the ice fullness is provided on the front surface of the water trough 116, with its lever 167 normally pressed by the projection 166a formed on the front side of the proximal end portion of the detecting plate 166. When the detecting plate 166 abuts against the ice pieces 121 in the process of inclining the water trough 116 so as to rotate clockwise relative to the water trough 116, the projection 166a is spaced from the lever 167 for rotating the switch SW₈, and thus the ice fullness can be detected. Incidentally, the projection 166a of the detecting plate 166 abuts against the lever 167 of the eighth switch SW₈ upon detection of no ice pieces 121, so that the ice making machine can be stopped when the detecting plate 166 falls down from the water tub 116 for some reason. Consequently, no ice pieces 121 can be formed in the state where the ice solidity is not recognized. Further, the free end portion of the detection plate 166 has a comb-like shape, whereby the force to be applied to the detection plate 166 when it collides with the ice pieces 121 can be reduced.

(Example of an electrical control circuit)

Figure 25 shows an electric control circuit in the ice making machine according to the second embodiment, in which a fuse F is connected between a power supply line R and a connection D, and a power supply indicator lamp L is connected between the connection D and a line T. Accordingly, (1) the sixth switch SW₆ for dispensing ice and the ice dispensing motor GM; (2) the seventh switch SW₆ for the actuating motor AM, the eighth switch SW₆ for detecting the ice fullness and a relay X₆ are connected in series between the connection D and the line T, respectively. Furthermore, a normally closed contact X₆-b₆ for the relay X₆ is connected between a connection E and a node K, which are arranged between the seventh switch SW₆ and the eighth switch SW₆. Between the connection K and the line T are connected in series accordingly (1) a relay X₂; (2) the ninth switch SW�9 for supplying water to be frozen and the water valve WV; and (3) a normally open contact X₃-a₁ for the relay X₃ and the actuating motor AM.

Furthermore, a normally closed contact X₂-b₁ for the relay X₂ and a normally closed contact X₃-b₁ for the relay X₃ are connected in series between the normally closed contact X₁-b₁ of the relay X₁ connected in series with the fuse F and a connection N arranged between the normally open contact X₃-a₁ of the relay X₃ and the actuating motor AM. A fan motor FN for the capacitor 111 is connected to the contact "a" of the thermo-metal switch Th₁ for detecting the completion of the ice releasing operation which is connected in series with the normally open contact X₂-a of the relay X₂, while the hot gas valve HV for supplying hot gas is connected to the contact "b" thereof. Further, between the normally closed contact X₁-b₂ of the relay X₁ and the line T, there are connected in series, respectively, (1) a normally open contact X₃-a₂ for the relay X₃, the swing motor RM and a normally closed contact X₂-b₂ for the relay X₂; and (2) a relay SR and the compressor CM. The tenth switch SW₁₀ for detecting the completion of the ice formation is connected to a connection P connected between the normally open contact X₃-a₂ of the relay X₃ and the line T. and the oscillating motor RM, and a protective thermo-metallic switch Th₂ is connected to a contact "a" of the switch SW₁₀, while the contact "b" thereof is connected to the connection D. Besides, the fan motor FM and the relay X₃ are connected in parallel.

Next, the operations of the ice making machine using the cam control mechanism according to the second embodiment of the invention will be described with reference to the timing chart shown in Figure 34.

(Initial operation)

After the operation of the power switch (not shown) of the ice making machine, the power supply indicator lamp L is illuminated and the compressor CM also starts supplying the refrigerant to the evaporator 131. Further, the actuating motor AM is rotated by the normally closed contacts X₁-b₂, X₂-b₁ and X₃-b of the relays X₁, X₂ and X₃ so that the water trough 116 taking the horizontal position starts to incline downward. The seventh switch SW₇ is turned on after the ninth switch SW₃ is turned off by the rotation of the motor AM, whereby the relay X₂ is activated to close the normally open contact X₂-a which is interlocked therewith and the relay X₃ is activated by the thermometal switch Th₁. Thus, the Actuating motor AM will continue its rotation through the normally open contact X₃-a₁ interlocked with the relay X₃, so that the water trough 116 is returned to the horizontal position without stopping in the inclined position. Besides, the relay X₃ is held by the normally open contact X₃-a₂ itself, which is interlocked therewith.

After resetting the water trough 116 to a predetermined position, the ninth switch SW9 is turned on to open the water valve WV, and water is supplied to the freezing chamber 129 defined in the water trough 116 through the water supply pipe 149. Since the water trough 116 is stopped in the horizontal position after being rotated once clockwise beyond the horizontal position that the wall 116d can be higher than the wall 116e and thereafter counterclockwise, a predetermined amount of water can be securely held in the freezing chamber 129. When water to be frozen is supplied in an excess amount to the freezing chamber 129, it flows over the dam plate 148 as described above and is discharged to the outside of the machine through the auxiliary chamber 146 and the water collecting section 119.

The rotation of the operating motor AM is stopped after turning off the seventh switch SW₇ when the motor AM is rotated, and the water trough 116 is stopped in the horizontal position. Further, the rotation of the swing motor RM is started after closing the normally closed contact X₂-b₂ interlocked with the relay X₂. After turning off the seventh switch 5W₇, the water valve WV is closed to stop the supply of water. However, the ninth switch SW₇ can keep the ON state.

(freezing activity)

A refrigerant is supplied to the evaporator 131 through a circulation pipe of the freezing system by an electricity-driven compressor CM, and cooling of the Freezing finger 117 provided on the freezing base plate 118 is started by the heat exchange action of the coolant. Since the freezing fingers 117 are immersed in the water to be frozen, the water starts to freeze around the freezing fingers 117 and gradually grow into inverted dome-shaped ice pieces 121. During such freezing action, the swing motor RM is continuously swinging. Consequently, the swing projection 159a of the swing member 159 rotated by the motor RM is engaged with the engagement piece 158 provided on the side wall 154c, so that the swing plate 154 is raised as shown in Figure 26. After the swing projection 159a is released from the engaging piece 158, the swing plate 154 falls by its own weight and abuts against the bottom 116a of the freezing chamber 129. Thus, the swing plate 154 repeats such swinging motion in the water to be frozen in the freezing chamber 129 during the freezing operation to constantly stir the water. In addition, since through holes 155 are formed in the swing plate 154, the water to be frozen flows through these through holes 155 while the swing plate 154 is swung, thereby causing jet currents that accelerate the stirring of the water to be frozen. Since the water to be frozen is constantly kept in a dynamic state as described above, the clouding of the ice pieces 121 to be formed around the freezing fingers 117 can be prevented, and thus transparent and clear ice pieces 121 can be formed.

(Ice clearance activity)

As shown in Figure 27, after the inverted dome-like ice pieces 121 are formed completely around the freezing fingers 117, the vibrating plate 154 is brought into contact with the ice pieces 121 in its upward stroke and finally exerts a downward counterforce on the vibrating motor RM through the engaging piece 158 and the vibrating projection 159a. Consequently, the mount 138 on which the vibrating motor RM is mounted starts to rotate counterclockwise on the bearing 134 so that the cam 159b of the vibrating member 159 depress the lever 162 of the tenth switch SW₁₀ for detecting the completion of ice formation so that it is changed from the contact "a" to the contact "b", and thus the completion of ice formation in the freezing unit 115 is detected. Whereupon the self-latching of the relay X₃ shown in Fig. 25 is released to close the normally closed contact X₃-b which is locked therewith and to start the rotation of the actuating motor AM. Thus, the cam plate 136 is rotated counterclockwise to tilt clockwise the lever 133b of the pivot shaft 133 which is engaged with the connecting rod 137 eccentrically connected thereto, and thus the water tray 116 starts to tilt downward (see Fig. 29). By this inclining movement of the water trough 116, the water remaining in the freezing chamber 129 flows into the auxiliary chamber 146 via the dam plate 148 and is then discharged therefrom to the water collecting section 119. Incidentally, during the operation in which the water trough 116 is inclined, the activation of the ninth switch SW₉ is canceled by the second cam 151 of the cam plate 136 which is rotated by the actuator AM (see Fig. 34).

The swing motor RM continues to rotate even after the tenth switch SW₁₀ is switched to the contact "b" for detecting the completion of ice formation when its lever 162 is depressed by the cam 159b of the swing member 159 (since the seventh switch SW₇ is turned off to close the normally closed contact X₂-b₂ of the relay X₂). Thus, the swing projection 159a provided on the swing member 159 is at a distance from the upper horizontal portion 158a so that the mount 138 can rotate clockwise under the resilient action of the torsion spring 139, which in turn switches the tenth switch SW₁₀ from the contact "b" to the contact "a" and temporarily stops the swing motor RM. Consequently, the upper end of the engaging piece 133e of the lever 133b is moved to a position lower than the upper end of the vertical part 138a so that the end 139b of the torsion spring 139 can engage the upper end of the vertical part 138a, the torsion spring 139 exerting no resilient action on the mount 138 (see Figure 33(b)). Whereupon the mount 138 starts to rotate on the bearing 134 in the counterclockwise direction by its own weight, thereby enabling the cam 159b to switch the tenth switch SW₁₀ from the contact "a" to the contact "b" and start the swing motor RM. The depression of the lever 162 is released when the notch 159c formed on the cam 159a comes to a position corresponding to the location of the lever 162, thereby switching the switch SW₁₀ is switched from the contact "b" to the contact "a" and the rotation of the swing motor RM is stopped (see Figure 33 (c)). Thus, the swing projection 159a provided on the swing member 159 stops at a position deviated from the inclination orbit of the engaging piece 158 of the swing plate 154 where it does not interfere with the inclination movement of the swing plate 154.

Upon arrival of the first cam 150 provided on the cam plate 136 at the lever 152 of the seventh switch SW₇, the switch SW₇ is turned on to activate the relay X₂ and open the normally closed contact X₂-b₁ interlocked therewith, as well as close the normally open contact X₂-a. In this state, the thermometal switch Th₁ for detecting the completion of the ice releasing operation is connected to the contact "b" since the ice pieces 121 are completely formed around the freezing fingers 117. Consequently, the relay X₃ is not activated and the rotation of the actuating motor AM is stopped so that the water trough 116 stops in an inclined position at a predetermined angle as shown in Figure 30. While in this state a part of the water to be frozen remains in the freezing chamber 129 due to the presence of the dam plate 148, such remaining water, which has been fully cooled during the previous freezing operation, is mixed with another part of water which is freshly supplied, so that the thus combined water to be frozen is effectively cooled. Furthermore, the ice pieces 121 formed around the freezing fingers 117 are exposed as such by the inclination of the water trough 116. Further, in the process of inclining the water trough 116 and stopping in the inclined position, the vertical part 160 of the swing plate 154 abuts against the freezing base plate 118, so that the swing plate 154 can be arranged diagonally above the bottom 116a of the freezing chamber 129 in the water trough 116 which later stops in the inclined position. The swing plate 154 also serves as a groove for guiding the ice pieces 121 falling off the freezing fingers 117 into the ice chamber 183.

Simultaneously with the stopping of the actuating motor AM, the hot gas valve HV is opened for supplying hot gas instead of the refrigerant to the evaporator 131 as shown in the timing chart of Figure 34, so that the freezing fingers 117 are rapidly heated by the freezing base plate 118. Consequently, the connection between the freezing fingers 117 and the ice pieces 121 is released, and the ice pieces 121 fall by their own weight, sliding on the upper surface of the swing plate 154 which is held at a predetermined inclined position by the vertical member 160, and are guided into the ice chamber 183.

The negative temperature load exerted on the freezer base plate 118 is cancelled by the falling of the ice pieces 121, and the temperature of the freezer base plate 118 is suddenly raised by the passage of the hot gas through the evaporator 131. This temperature rise is sensed by the thermometal switch Th₁, which immediately switches to the contact "a" to activate the relay X₃, which in turn closes the normally open contact X₃-a₁, which is interlocked therewith, and allows the actuator AM to resume rotation. Furthermore, the hot gas valve HV is also closed, so that the supply of the refrigerant to the evaporator 131 is resumed.

The pivot shaft 133 is rotated clockwise under the action of the cam plate 136, the connecting rod 137 and the lever 133b by this rotation of the motor AM, and the water tray 116 is correspondingly rotated clockwise so that it starts resetting to the horizontal position. Further, the second cam 151 of the cam plate 136 comes to the lever 153 of the ninth switch SW₀ when the motor AM resumes rotation so that the switch SW₀ is rotated as shown in Figure 31, thereby reopening the water valve WV for supplying water to be frozen to the freezing chamber 129.

After the first cam 150 of the cam plate 136 is released from the lever 152 of the seventh switch SW₇, the activation of the switch SW₇ is canceled to close the water valve WV and stop the supply of water to be frozen as well as to stop the actuating motor AM. This is because the relay X₃ is latched to open the normally closed contact X₃-b thereof. Thus, the water trough 116 is stopped in the horizontal position.

Incidentally, in the second embodiment, the resetting of the water trough 116 to the horizontal position is carried out by once rotating the water trough 116 clockwise beyond the horizontal position such that the free end portion thereof (the side wall 116d) can be higher than the fixed end portion thereof, and then by rotating it counterclockwise to stop in the horizontal position, as shown in Figure 32. Namely, when the water to be frozen is supplied in a sufficient amount to the freezing chamber 129 with the dam plate 148 provided in the water trough 116 being arranged at a high level so that the water flows over the dam plate 148, a necessary amount of the water to be frozen is surely supplied to the freezing chamber 129 when the water trough 116 is reset to the horizontal position. This will help prevent potential problems caused by a lack of water to freeze.

Further, as the pivot shaft 133 rotates clockwise, the upper end of the engaging piece 133e of the lever 133b shifts upward to a position higher than the upper end of the vertical part 138a of the mount 138 so that the end portion 139b of the torsion spring 139 comes into engagement with the upper end of the engaging piece 133e (see Figure 33(a)). Thus, the mount 138 is rotated clockwise on the pivot shaft 133 by the spring force of the torsion spring 139 so that the swing projection 159a of the swing member 159 can come into the operating position where it can be engaged with the engaging piece 158 of the swing plate 154. Consequently, after the activation of the relay X₂ is cancelled, by turning off the seventh switch SW�7, the normally closed contact X₂-b₂, which is interlocked therewith, is closed to rotate the swing motor RM and to allow the swing plate 154 to resume and continue the swinging motion during the freezing operation.

When the water trough 116 is tilted after the completion of the ice freezing operation, storing a predetermined amount of ice pieces 121 in the ice chamber 183 by repeating the freezing operation and ice releasing operation, the detecting plate 166 collides with the group of ice pieces in its tilting operation and is prevented from tilting further. Thus, the detecting plate 166 is rotated clockwise relative to the water trough 116 to turn on the eighth switch SW�8 for detecting the ice fullness. In this state, the seventh switch SW₇ shown in Figure 25 is turned on to activate the relay X₁, thereby turning on the normally closed contacts X₁-b₁ and X₁-b₂. opened to stop the rotation of the actuator motor, as well as to stop the excitation of the compressor CM.

Incidentally, in the illustrated embodiments of the invention, the at predetermined distances from the lower surface the freezing fingers 36, 117 extending from the freezing base plate 34, 118 are tapered downward. However, the shape of the freezing fingers 36, 117 is not limited to this, and various modifications such as round rods, pins, etc. can be suitably used.

Claims (7)

1. Ice making machine with: an evaporator (22, 131) connected to a freezing system having a compressor (CM) and a condenser (18, 111); a freezing base plate (34, 118) having a plurality of freezing fingers (22, 131) formed on the lower surface thereof, the evaporator (22, 131) being provided on the upper surface thereof; a water trough (24, 116) pivotally mounted to maintain a normally horizontal position and in which a freezing chamber (32, 129) is defined for carrying water to be frozen into which the freezing fingers (36, 117) are to be immersed; wherein the water trough (24, 116) is adapted to be inclined downwards after the water has frozen around the freezing fingers (36, 117) to form ice pieces (70, 121) and to be returned to the horizontal position after the ice pieces (70, 121) are released; a control cam (13, 150) which is rotated by an actuating motor (AM) for tilting and resetting the water trough (24, 116); and a control switch (SW₁, SW₇) provided on the fixed side corresponding to the arrangement of the control cam (13, 150) for performing a cam action according to a predetermined time; wherein the control cam (13, 150) and the control switch (SW₁, SW₇) are designed to control at least the tilting and resetting of the water trough (24, 116) as well as the stopping thereof in such positions by the actuating motor (AM); marked by: a swing plate (44, 154) provided in the freezing chamber (32) so that it can be swung therein; a vibrating motor (RM) provided outside the water trough (24), which is vertically displaceable and which is adapted to vibrate the vibrating plate for stirring the water present in the trough. 2. Ice making machine according to claim 1, comprising: a first cam (13) which is the control cam, a second cam (15) and a third cam (17) which are coaxially provided at predetermined intervals on the rotary shaft of the actuating motor (AM) for tilting and resetting the water trough (24); and a first switch (SW₁) which is the control switch, a second switch (SW₂) and a third switch (SW₃) provided on the fixed side corresponding to the arrangement of the first, second and third cams (13, 15, 17) for performing cam actions with the rotation of the actuating motor respectively in accordance with a predetermined timing; wherein the second cam (15) and the second switch (SW₂) are designed to control the opening and closing of a hot gas valve (HV) for supplying a hot gas to the evaporator (22) during the ice releasing operation; and the third cam (17) and the third switch (SW₃) are designed to control the opening and closing of a water valve (WV) for refilling water to be frozen to the freezing chamber (32) during the resetting movement of the water trough (24). 3. Ice making machine according to claim 1 with: a cam plate (136) having formed thereon the control cam (150) and a second cam (151) provided on the rotary shaft of the actuating motor (AM) for tilting and resetting the water trough (116); and the control switch (SW�7;) and a second switch (SW�9;) which are arranged on the fixed side according to the arrangement of the first cam (150) and the second cam (151) are provided for performing respective cam actions according to a predetermined time under the rotation of the actuating motor (AM); the second cam (151) and the second switch (SW�9) being adapted to control the opening of the water valve (WV) for refilling water to be frozen to the freezing chamber (129) during the resetting movement of the water trough (116). 4. Ice making machine according to one of claims 1 to 3 with a detection switch (SW₄) for detecting the termination of ice formation, arranged in the displacement orbit of the oscillation motor (RM); a first engagement means (62) provided on the oscillating motor (RM); and a second engagement means (61) provided on the oscillating plate (44) which can come into engagement with the first engagement means (62); wherein the inclination of the water trough (24) is designed to be started by driving the actuating motor (AM) after detecting the completion of ice formation around the freezing fingers (36) by operating the detecting switch (SW₄) which is activated by sliding the swinging motor (RM) in a predetermined direction when the swinging plate (44) is brought into contact with the ice pieces (70) formed around the freezing fingers (36) during the swinging movement of the swinging plate (44) by the swinging motor (RM) through the first and second engaging means (62, 61) so that a counterforce is exerted on the swinging motor (RM), thereby driving the actuating motor (AM). 5. Ice making machine according to one of claims 1 to 4, in which the resetting of the water trough (24) is started after detection by a thermo-metallic switch (th) for detecting the completion of the ice releasing operation. 6. An ice making machine according to claim 3, comprising pivot pins (130) formed along the long side of the water trough (116) perpendicular to the inclination direction thereof and pivotally supported on the main body of the ice making machine; a pivot shaft (133) pivotally supported on the main body of the ice making machine, one end of which is inserted into the axial end of the pivot pin (130) so as to be pivotable integrally therewith, and a lever extending radially from the other end thereof; and a connecting rod (137) pivotally fitted loosely on a projection (133c) at the other end thereof and pivotally supported eccentrically on the cam plate (136) at the other end thereof; wherein the pivot shaft (133) is rotated clockwise or counterclockwise through the connecting rod (137) by rotating the cam plate (136) by the actuating motor (AM), thereby allowing the water trough (116) to tilt downward or return to the horizontal position. 7. An ice making machine according to any one of claims 1 to 6, comprising a duct (147) provided to project horizontally from the water trough (116), and a water collecting portion (119) defined on the main body of the ice making machine at a position below the inclination orbit of the duct (147); the duct (147) being designed to abut against the upper edge of the water collecting portion (119) when the water trough (116) is inclined downward, thereby maintaining the water trough (116) in the inclined position.