US2996895A - Refrigeration apparatus - Google Patents

Description

Aug. 22, 1961 H. s. LIPPINCOTT 9 3 REFRIGERATION APPARATUS Filed March 2", 1959 5 Sheets-Sheet WG. 2. INVEN' OR.

Aug. 22, 1961 H. s. LIPPINCOTT REFRIGERATION APPARATUS 5 Sheets-Sheet 2 Filed March 27. 1959 m T m V m 1951 H. s. LIPPINCOTT REFRIGERATION APPARATUS 3 Sheets-Sheet 3 Filed March 27, 1959 INVENTOR. #011 ,4/1/0 I [/A /#(077 United States Patent 2,996,895 REFRIGERATION APPARATUS Holland S. Lippincott, River-ton, NJ., assignor to Philco Corporation, Philadelphia, Pa., a co'poration of Pennsylvania Filed Mar. 27, 1959, Ser. No. 802,421

2 Claims. (Cl. 62-138) This invention relates to ice block reezng and harvesting apparatus, or so-called ice makers, of the type which use a flexible or twistable ice tray. t

Although devices incorporating such trays have been proposed in the past, their use has thus far been a limited one and has not been entirely satisfactory. For instance, when automatic performance of the twisting, harvesting and re-filling was attempted, it was found that very complicated and expensive structures and controls were required. i

In addition, it was hitherto most difiicult, .if 'not impossible, to maintain the required form of flexible tray, when repeatedly twisting the tray This, of course, was largely due to the unavoidableand rather severe changes of temperature which are involved in the alternate freezing of water and admisson of new amounts of water. Aspositive flexing is required, for the breaking loose of ice cubes, it seemed unavoidable that the tray, after a certain amount of use, tended either gradually or suddenly, permanently or at least for extended`timesto take a so-called "set" or deformation. This in turn interfered with a number of required Operations, for instance with the filling of tray compartments to a proper, uniform level. i I

It is the basic object of this invention to overcome these and other difiiculties, hitherto encountered with fiexible ice trays. A specific objectis to provide a simplified and yet highly effective, automatic device for operating a flexible ice tray. Another specific object is to minimize that flexing operation which tends to cause ,the tray to take a set. It was found highly desirable', in conn'ection with this last object, to flex the tray twice, slightly, in opposite directions, rather than only once and more sharply. It was further' found to be possible, by this very duplication of flexing Operations, to reduce rather than tdincrease the complexity of the apparatus.- .The 'way iii "which these objects and results' have been realized will best "be explained by consideration of a p'referred ernbodiment of the invention. l

"In the drawing, FIGURE 1 is a front view, partly in section, of such an' -emb'odiment, wherein the ice tray is shown in a normal, operative position'thereof. FIGURE 2 is `a detail view, taken along line 2-2in FIGURE 1 after turning the ice tray into a different operative posi tion. 'FIGURES 3 and 4 are perspective detail views showing the ice tray in further operative positions. FIG- URE 5 is a perspective diagram of mechanical linkages and electrical crcuits forming principal, parts of 'the apparatus. FIGURE 6 is a schematic representation of said electrical circuts, and FIGURE 7 isa chart of successve functions of the several circuit elements, during one ofjthe Operating cycles thereof. V

Referring to FIGURE 1: refrgerator 10 has evaporator 11 installed therein, which in turn has ice cube freezing compartment 12 separated. from other evaporator portio'us by vertical partition 13. An upper portion of 'the ice cube freezing compartment contains structune '14 for 'the permanent support of movable ice tray 15, while a basket 16 is removably inserted into a lower portion of said compartment for the storage of ice cubes 'made by said tray. For the purpose of peiodically'filling the tray with water, a single pipe or spout 17 is provided,

which extends through insulation 18 between inner and' outer shells 19, 20' of the refrigerator, '1`ray15 made of flexible and desirably resilient material, such as soe called linear polyethylene, and is sufliciently long and narrow to allow appreciable although controlled, elastic twisting of either end of the tray, relative to the other end, so as to distort the entire tray suflioiently for breaking the ice cubes loose. A typical tray 15 may, for' instance, be about four inches wide and twelve inches long,

FIGURE 2 illustrates one of the twisted conditions of tray 15, while in FIGURE 1, showing the normal freeze' ing position, the tray is not twisted. As clearly shown in FIGURE 2, the tray forms a flexible link between a pair of rigidly constructed, relatively movable mechanisms, installed on supporting structure 14. In order to provide support for this semi-rigid system, structure 14 includes a hearing plate 21, pivotally supporting the back end of flexible tray 15, which end is here shown at the right. In order to automatically move said end of the tray, bearing plate 21 also supports a motor unit 22, on the side opposite the tray, with motor output shaft 23 extending through a central portion of the hearing plate, where the shaft is fastened to said end of the tray. A rigid web 24, secured to hearing plate 21, extends toward the front portion of the apparatus, shown at the left; Here another hearing plate 25 is attached to web 24, in order to provide pivot means for a second shaft 26, secured to the front end of the tray. The two shafts are in line with one another. A free end of the second shaft carries a mechanical stop device 27, in front of hearing plate 25, while the rear shaft 23 carres a switch actuator 28, between the tray and the rear hearing plate. The stop and switch devices 27, 28 are used for automatic twsting and positioning of tray 15, as will present- URE 1, and the breaking loose and discharge of ice front hearing plate 25.

cubes has been further promoted by an additionaland, reverse twisting of the tray. The reverse direction of the second twisting action will beapparent when it is considered that in FIGURE 2 the back end of the tray had been twisted counterclockwise relative to the front end, whereas in FIGURE 3, said back end has been twisted clockwise" relative to the front end. The latter figure also shows details of the stopping mechansm 27, utilized for these purposes. This mechanism comprises a disc 29, secured to front shaft 26 by set screw 30 so that the disc is movable with the front shaft and thus with the front end of the tray. The disc has two radially extending surfaces 31, 32 thereon. The first of these'surfaces is here shown as engagng a rigid stop pin 33 on'. It will be understood-that in the position of FIGURE 2, the other surface 32 engages the pin 33,' as best shown in FIGURE 5.

As initially noted, it has been found that the danger of a-permanent or semipermanent' set, taken by the flexible.

tray, is greatly reduced by the use of reverse flexing, i combined with the feature of making 'such flexing relatively slight. Exact details as to the proper extent of flexing depend on a number of variables, including for -instance the material as well as the exact geoine-try of the I tray; and it is 'evident that many variations a're possible' operation, generally requires distortion of one end, relative to the other, by approximately 40=; and such distortion involves a definte danger of taking a set. According to the invention, the form and material of the. tray can be substantially the same as has been usual, but' harvesting of ice blocks is performed by first flexin'g'in' one direction and then in the other, and the individual degrees of flexing are substantially less than 40' although they, when disregarding their opposite directions, desirably amount to same total of about 40 which has been used in conventional practice. For instance, the preflexing shown in FIGURE 2 may amount to about 5 to and the final flexing shown in FIGURE 3 may amount to about 30 to 35. In other cases these values may be modified to about and respectively. case the danger of taking a set is greatly reduced, not only in proportion to the reduced angles of twisting or fiexing. The apparent reason for the great improvement is that set-inducing stresses are, at each temperature, encountered only after a certain amount of safe, elastic flexing.

It will thus be seen that the invention is of definite value for preserving the desired form of an ice tray and for thus insuring proper and smooth performance of filling, turning and other Operations. This applies regardless of whether such operations are performed by full automatic devices or otherwise. It Will however be seen from the further description, which follows presently, that the invention is of particular utility in connection with automatic operation.

Additionally illustrated in FIGURE 3 is a vertically movable, horizontally extending feeler bar 34, supported by a crank arm and used for automatically determining whether basket 16 has been filled with ice cubes. In the position of FIGURE 3 this feeler bar is raised, so as not to interfere with the discharge of new ice cubes and, moreover, to prepare the feeler bar for subsequent lowering thereof into the basket, to explore the new level of ice cubes. The raising and lowering of the feeler is performed, during each operative cycle of the ice tray, by mechanism to be described herenafter.

Referrng next to FIGURE 4, feeler 34 is here shown as having been lowered into basket 16, to determine whether any further operations of the ice tray are required, for the time being. The figure indicates that basket 16 is not yet full and that feeler 34 has therefore reached a relatively low position, on reverse operation of said mechanism thcreof. It is therefore desirable that tray 15 be filled with water, again; and for this purpose the tray is shown as having been turned back toward normal.

More specifically, the tray is shown as not yet entirely in normal position; it is in process of turning backwardly, in oblque positions and without twisting or deformation. Water is now admitted to the tray, through pipe 17, and begins to fill the oblique tray as clearly shown at 36. This particular way of filling the tray, in oblique position, has been adopted in combiration With the use of compartments 37, formed in the tray and which are separated from one another by partition walls 38 of somewhat lower height than the tray itself. Rapid, uniform filling of all compartments is facilitated by these features, as has been disclosed in copending application Serial No. 826,64O filed July 13, 1959, by M. G. Shoemaker under the title Freezing Equipment and Method of Operating It, which is assigned to the assignee hereof. Pursuant to the filling of the tray, which starts or continues in the position of FIGURE 4, the tray continues to turn back toward the normal or freezing position of FIGURE 1, and further reverse rotation of the tray is then stopped, in the latter position, by means of automatic switching apparatus.

Said switching apparatus is directly and indirectly connected with the aforenentioned actuator member or disc 28 and is best shown in FIGURE 5. It will here be noted that said actuator disc has two fingers 39 and 40. Both of these or the entire actuator are desirably made of insulating material. The first finger 39 successively ngages a motor stop switch 41, a tray fill switch 42 and a motor reversing switch 43, and the latter switch is additonally engaged by the second finger 40. Additionally there is provided a basket feeler switch 44 and a In each i can therefore be of very short duration.

tray feeler switch 45, the latter being desirably of thermostatic type and provided with a conventional, resetting heater (FIGURE 6), while the basket feeler switch 44 (FIGURE 5) is shown as being actuated by feeler 34 and crank 35, through the intermediation of a linkage member 46 pivoted at 47, which member can also be actuated by a cam 48 on motor shaft 23. The illustration of the basket feeler unit is purely dagrammatic; this part of the mechanism is not, per se, claimed herein and has been drawn only in the interest of a complete showing of the interconnected circuit elements 41 to 45 and associated parts.

Assuming that ice cubes have been frozen in tray 15 while the apparatus was in the position of FIGURE 5, such freezing ultimately results in closing thermostatic switch 45 on tray 15. Previously, basket feeler switch 44 has been closed, whereas stop and fill switches 41, 42 are open and toggle 49 of reversing switch 43 is in downward position, as shown. The closing of thermostat switch 45 now causes electric current to flow from line Ll through switches 44, 45 and motor 50 to line L2, as best indicated by FIGURE 6. As a result motor 50 now rotates; and it may be assumed that, in the illustrated downward position of toggle 49, a conventional reverse starting mechanism 51 has caused the motor to rotate output shaft 23 counterclockwise as seen from the front of FIGURE 5.

In this rotation, surface 32 on disc 29 of mechanical stop member 27 soon encounters pin 33, thereby stopping the counterclockwise rotation of the front part of tray 15, while such rotation of motor shaft 23 continues. The latter rotation accordingly distorts and prefiexes the fiexible tray, by twisting the back end, as shown in FIGURE 2. This serves to start loosening of the ice cubes, which otherwise would adhere strongly to the tray.

This first twisting action can be kept very slght and Soon thereafter, accordingly, the counterclockwise rotation of shaft 23 and disc 28 causes finger 40 to raise toggle 49 of reve'sing switch 43, thereby reversing the starting unit 51. As a result, the counterclockwise rotation of motor shaft 23 is now reversed and clockwise rotation takes place.

During this clockwise rotation the following actions take place. First, tray 15 is resiliently untwisted. Next, the tray is freely returned to normal position, passed through such position, and then turned further, clockwise, toward the partly overturned position of FIGURE 3. During this latter phase, finger 39 first allows stop switch 41 to close, by resilience of a switch element which in the previous Operations had been bent into open positions. The same finger then overrides open switch 42, without closing it. Some time thereafter there occurs the reverse engagement of mechanical stop member 27, by pin 33, while the motor continues to run; the consequent reverse twisting of tray 15, which as noted above. is somewhat more extensive than the preliminary or opposite twisting, but still relatively slight as Compared with a single-twist operation; and the ensung discharge of ice blocks from the tray, and collection thereof in basket 16. Discharge of the ice is facilitated by the feature that the tray compartments have curved boundaries and that the twisted tray, in harvesting position, is only partly overturned, so that the ice blocks are allowed and caused, by gravity and twisting action, to slidedownwardly on rounded or elliptical bottom sur faces and out of the correspondingly formed compartments of the tray. Finally, finger 39 engages raised toggle 49 of reversing switch 43, returnng this toggle to the lower position, re-reversing motor 50, and starting return motion of tray 15 into normal position.

The rotation of shaft 23 into harvesting position has also caused similar rotation of basket feeler switch cam 48, and, shortly before establishment of the harvesting position, this 'cam has engaged linkage 46, raisng basket feeler 34 and resetting basket feeler switch 44 into open position. The ensuing counterclockwise or return rotation of shaft 23 and cam 48 allows the weight of basket feeler arm 34 to return linkage 46 toward closed position of basket feeler switch 44. If the basket has been filled to the top, elements 34 and 46 cannot in this gravitational return motion reach their final positions, so that basket feeler switch 44 is not entirely closed; if, on the other hand, room is left in the basket for one or more additional loads of ice blocks, the final positions of elements 34, 46 are reached, so that switch 44 is completely closed during the reverse rotation of the mechanism, thereby re-establishng the position of the basket feeler switch as required for the start of an operative cycle, which has been described above. In the meantime, the tray feeler or thermostat switch 45 has also been reset, into open position, for instance by operation of well-known thermostat heater means 54, shown in FIGURE 6.

An important, additional function of the counterclockwise return rotation of the system is the temporary closure, 'by finger 39, of fill switch 42. As indicated by FIGURES 5 and 6, the closure of this switch energizes solenoid 52 of valve 53 in fill line 17, thereby opening this valve and causing the filling operation, the effect of which has already been described. The filling, as mentioned, takes place during completion of the counterclockwise return rotation of the tray. The filling is terminated When finger 39 overrdes the resilient, actuating pole of fill switch `42, de-energizing solenoid 52 and allowing self-closing valve 53` to close. Shortly thereafter, said finger `39 reaches the actuating pole of stop switch 42 and opens that switch, thereby de-energizing 'and stoppng motor 50 and re-establishing the normal or freezing position of FIGURE l.

In the chart of FIGURE 7 the first column shows the above-described, successive Operations of tray 15, by selfexplanatory legends. In the columns showing the positions of elements 41 to 45, 50 and 53-, the Symbol O means "open, C means closed, D means "down, U means up, F means forward rotation and R means reverse rotation. Those of the successive switch re- Versals which initiate the Operations of the motor or valve solenoid have been emphasized by underscoring in this chart. It will be seen, for instance, that throughout the treezing operation (line I of the chart), sWiches 41, 42 are open and 44 is closed, while switch `45 gradually closes; and on completion of such closure, there ensues forward operation of motor 50 (line II of the chart).

With respect to certain switch Operations, occurring during an early phase of the turning of the tray (and which are marked by an asterisk), it may be noted that switch 41 is closed by finger 39 a short time after the start of the reverse running of the motor, when actuator 28 has returned to and slightly beyond the original position of FIGURE 5, and that thermostat switch 45 is reset to open, a short time thereafter, by the 'action of the heater which will be understood readily from FIGURE 6. The timely opening of switch 45 is important, as otherwise, cycling would continue improperly and water would be spilled into the ice basket. It is equally important for the cycle that, of the two Operations occurring during a first phase of the reverse turning of the tray (double asterisks), the closing of switch 42 is definitely efiected, at a predeterrnined moment, by finger 39, returning -from a position adjacent switch 49, whereas the closing of basket feeler switch 44 can be caused by the feeler mechanism to occur at any desired time prior to the end of the reverse turning, but only if the ice basket is not full.

The Operating cycle of the illustrated machine ends in the same positions of the diierent switches and operating parts which had existed at the start. Such cycles are therefore automatically repeated. They produce ice at least as rapidly as has hithe'to been possible with the aid g flxibe ways. The operation continues u til the 6 moment when the ice basket has been filled; at such time basket feeler switch 44 is no longer closed (FIGURE S). The succession of cycles accordingly terminates, with a full tray, upon the last establishment of a position generally resembling that of FIGURE 5.

The succession of cycles is evidently resumed, without the necessity of any manual switch or valve operation or the like, when the ice basket has been emptied. It is assumed, of course, that the refrigerator is kept closed during most of the time, so that suitably low temperatures can be maintained by evaporator 11.

It should further be noted that the semiflexible mechan sm, characterizing this invention, and which comprises rgid actuators 27, 28, 48 in mechanical series wi-th flexible tray 15 (FIGURE 2), has not only facilitated actuation of automatic Controls 41 to 45, for reversible operation 'of the mechanism (FIGURES 5 to 7), but has at the same time added to the safety and reliability of mechanical ice tray operation (FIGURES 3, 4 etc.). The alternate, -rightward and leftward twisting Operations, applied to the ice tray, have the advantage thatsafe discharge of ice blocks can be obtained with a relatively small degree of twisting, applied each time, thereby minimizing the danger of -a permanent or semipermanent set of the tray. Hitherto it had appeared that rather complex mechanism was required for automatic performance with a single twisting operation. Far from adding to such Complexity, the mechanically safe, double or alternate twisting motion, provided by the present invention has additionally simplified electrical circuitry and structure, as explained above. Since each of the circuit elements and machine parts must be constructed for operation under severe conditions, a considerable saving and improvement as to mechanical reliablity has been achieved in this way.

Although only a single, automatically operated embodiment of the new ice maker and a single type of operation thereof have been described, it should be understood that the details thereof are not to be construed as limitative of the invention, except insofar as is consistent with the scope of the following claims.

I claim:

1. An ice maker comprising: a resilient tray; a first pivot and control structure, secured to one end of said tray, for mechanically limiting rotation of 'such end in either direction; a second pivot and control structure, in line with the first structure, and Secured to the opposite end of the tray, for enforcing intermittent, more extensive, opposite rotations of said other end, said second control 'structure including a shaft Secured to the corresponding end of the tray, a motor for rotating said shaft, a cam structure on said shaft, a start switch associated with said tray for starting the motor in one direction when freezing of water in the tray has been completed, a reversing switch associated with the cam structure for reversing the motor after rotation in said one direction and for a second reversal back into said first direction, and a stop switch, associated with said cam structure for stopping the motor pursuant to the second reversal.

2. An ice maker as described in claim 1, additionally including, as part of said second control structure, switch and valve means associated with the cam structure, for controlled -admission of water to the tray.

References Cited in the file of this patent UNITED STATES PATENTS 2,454,960 Berkeley Nov. 30, 1948 2,484,017 Copeman Oct. 11, 1949 2,757,S20 Sampson Aug. 7, 1956 2,772,542 Gaugler Dec. 4, 1956 2,782,609 Galin Feb. 26, 1957 2,840,507 Heath June 24, 1958 2.846,8, 4 Galia Aug. 12, 1958

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