Ice tray
CROSS REFERENCE TO RELATED APPLICATIONS 
     This application is a continuation-in-part of my copending application Ser. No. 660,239, filed Feb. 23, 1976, now abandoned. 
    
    
     BACKGROUND OF THE INVENTION 
     1. Field of the Invention 
     The present invention relates to an ice tray for producing pieces of ice and more particularly to an improved freezer tray providing a number of mould cavities for producing ice pieces individually. 
     2. Description of the Prior Art 
     Refrigerator ice cube trays often take the form of a substantially rectangular tray which is compartmentalized into a number of cavities in a variety of structures. 
     In one embodiment a mechanically displaceable partitioning structure is used so that subes can be mechanically cammed out of their cavities after the water has been frozen. 
     In another embodiment the ice cube tray takes the form of individual cells or cavities and in still other embodiments the ice cube tray includes the combination of a plurality of individual cells formed of a plastic material arranged in longitudinal rows and transversely aligned and united at their upper margins into an integral unit. 
     The following United States patents illustrate the variety of structures and shapes that have been developed: 
     U.S. Pat. No. 1,889,481 issued Nov. 29, 1932 
     U.S. Pat. No. 2,269,642 issued Jan. 13, 1942 
     U.S. Pat. No. 2,481,525 issued Sept. 13, 1949 
     U.S. Pat. No. 2,537,915 issued Jan. 9, 1951 
     U.S. Pat. No. 2,591,261 issued Apr. 1, 1952 
     U.S. Pat. No. 2,796,742 issued June 25, 1957 
     U.S. Pat. No. 2,810,338 issued Oct. 22, 1957 
     U.S. Pat. No. 3,021,695 issued Feb. 20, 1962 
     U.S. Pat. No. 3,120,112 issued Feb. 4, 1964 
     U.S. Pat. No. 3,122,898 issued Mar. 3, 1964 
     U.S. Pat. No. 3,214,128 issued Oct. 26, 1965 
     U.S. Pat. No. 3,317,177 issued May 2, 1967 
     It is an object of the invention to provide in an ice tray for forming a number of ice pieces or ice cubes as they are commonly called, the combination of a plurality of individual cavities formed from a resilient plastic material with each cavity open at the top and having resilient walls of relatively thin generally uniform thickness throughout their extent, said cavities being arranged in longitudinally and transversely aligned rows in spaced apart relation and being united at their upper margins or perimeters defining their open tops into an integral unit, each cavity having an internal configuration such that each has an axis of revolution lying substantially in the plane of its open top and defined by a central bottom wall of part-circular or part-cylindrical configuration flanked by spaced opposed generally part-conical side walls of opposite symmetry to thereby present a generally hexagonal perimetral configuration defining the top opening thereof, said cavity having a plane of symmetry extending substantially perpendicularly to the plane of the open top that includes the axis of revolution and the apices of the part-conical side walls and in which the dimension of each cavity measured in the plane of the top opening and in the direction of the axis of revolution is at a maximum in the region of the axis of revolution whereby moulded pieces of ice having a configuration imparted by each cavity can be easily displaced out of the top opening to the one side of the axis of revolution under the application of force to such moulded pieces of ice at the other side of the axis of revolution. 
     In conventional trays, once the water or other liquid freezes into ice, it is usually quite difficult to remove the ice cubes on a one-at-a-time individual basis. Generally, it is necessary to place the entire tray under flowing water to loosen all of the cubes from the pockets simultaneously so that all of the cubes are normally removed at the same time. Various complex mechanisms have been provided for loosening ice cubes, but these are often difficult to operate, particularly where the water, before freezing, overflows upon the surface of the sheet or flows around the various dividers or partitioning mechanisms used for the removal of the ice so as to interconnect all of the cubes. 
     Furthermore, many of these mechanisms are relatively expensive, difficult to use, and often malfunction so that portions of the cubes break off while other portions remain frozen to the partitioning mechanisms. Thus, the present invention relates to an improved form of a so-called ice cube tray which comprises a relatively inexpensive, simplified, one-piece construction wherein individual pieces of ice may be removed on a one-by-one basis with little or no trouble or, in the alternative, a simple twisting motion will loosen all of the individual pieces for simultaneous removal. 
     SUMMARY OF THE INVENTION 
     The invention disclosed herein contemplates an ice &#34;cube&#34; tray having specially shaped pockets or cavities for allowing individual ice pieces to be removed on a one-at-a-time basis. Each cavity has a curved bottom portion generally shaped in a part circular arc, preferably a part-cylindrical configuration and a pair of generally concave opposed side walls of generally part-conical configuration whose central apices provide a pivot axis about which the ice piece rotates when pressure is applied to the end of the piece to slide the piece along the curved bottom portion for removal from the cavities. The sheet which interconnects the cavities should preferably be resiliently twistable to loosen all of the ice cubes simultaneously, if desired, and legs on the underside of the sheet may be provided with notches for engaging portions on the upper side of the sheet of another tray to facilitate compact tray stacking, one upon another, without tray slippage or interference with formation of the ice pieces. 
     In the preferred embodiment, the tray includes a substantially flat, horizontally arranged thin sheet having a number of spaced apart individual cavities integrally formed therein and depending therefrom. Each of the cavities is specially shaped and the top opening is generally hexagonal. The curvate shaped bottom portion is comprised of a part-cylindrical bottom wall in the preferred embodiment which integrally merges into opposed perimetral ends of the hexagonal top opening. 
     Each of the top openings has a longitudinal axis positioned between the opposite perimetral ends thereof and a transverse axis normal thereto. The longitudinal axis is normal to the longitudinal axis of the sheet. Each of the side walls of the cavities is concave and of opposite symmetry with the opposed central apices of each opening being parallel to the generating axis of the cylindrical bottom wall to define an axis about which the ice cube can be rotated for removal. This axis is parallel to the transverse axis and the transverse width of the opening measured along the pivot axis is a maximum while the transverse width measured across the ends of the opening which integrally merge with the bottom portion is a minimum. 
     The opposed part conical side walls extend uniformly upwardly and outwardly and centrally, measured in a vertical plane bisecting the cavity, the angle between each side wall and bottom wall approaches 105°. 
     The present construction is such that force applied to one end of an individual piece of ice will cause it to rotate about the axis and slide out of the cavity for easy individual removal from the tray. Alternatively, the sheet formed of a resilient material may be subjected to twisting pressure to loosen all of the ice pieces within the cavities for removal. 
     The ice tray of the present invention is preferably rectangular having a first axis corresponding to the longitudinal axis of the sheet and a second axis corresponding to the transverse axis of the sheet. The pockets are arranged in two parallel rows oriented along the longitudinal axis of the sheet such that the longitudinal axis of the individual top openings is parallel to the transverse axis of the sheet and the transverse axis of the top openings is parallel to the longitudinal axis of the sheet. The sheet may include a raised rim portion integral therewith and having the rim portion extending upwardly from the flat portion of the sheet and completely surrounding the sheet to contain liquid poured onto the sheet. 
     Furthermore, the sheet can be provided with apertures passing through the sheet and interiorly of the raised rim portion for draining excess liquid so that cavities may be filled but not beyond the flat upper surface of the sheet to preserve the individuality of the pieces of ice to be formed in the cavities. 
     The combination of the flat sheet and individual spaced cavities whose wall thicknesses throughout are thin and substantially uniform includes generally hourglass-shaped configurations between adjacent cavities. Notched channels may be provided in the sheet extending between the top openings of the cavities at their narrowest separations for allowing flow of liquid between adjacent cavities for levelling liquid throughout. 
     Additionally, the rim portion may be provided with reinforcing rib; additional reinforcement may be provided on the underside of the tray between individual pockets; and a pair of reinforcing support legs adjacent each end of the sheet may be provided. Further, the reinforcing support legs may include an elongated portion integral with the sheet and extending downwardly therefrom, and may further include a lower end portion having a means adapted to engage the narrow portion between adjacent openings on the surface of another tray for stacking purposes. This allows a plurality of trays to be compactly stacked one above the other and prevents tray slippage. 
     In the preferred embodiment of the present invention the curvature of the continuous cylindrical bottom wall is 180° with its axis of generation located between opposed apices of the side walls of the generally hexagonal top opening. The side walls are slightly bowed or concave uniformly upwardly since they are integral with the sheet and form a unitary continuous wall from the side wall portion of the opening to the 180° cylindrically curved bottom wall and make an angle of the order of 105° centrally and measured in a vertical plane. 
     The present invention contemplates a unitary structure which may be molded out of plastic material in a single piece and wherein water or other liquids may be easily poured into the pockets by even a child. The overflow drains from the sheet through the drain apertures and uniform pieces of ice are insured due to the levelling achieved by the notched openings between adjacent pockets. The individuality of the pieces is maintained and they may be removed one at a time with ease. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     These and other objects and advantages of the present invention will become more apparent upon reading the following detailed description, the claims and the attached drawings in which: 
     FIG. 1 is a perspective view of the ice tray of the present invention; 
     FIG. 2 is an elevational side view of the ice tray of FIG. 1; 
     FIG. 3 is a top view of the ice tray of FIG. 2; 
     FIG. 4 is an end view of the ice tray of FIG. 3; 
     FIG. 5 is a bottom view of a portion of the ice tray of the present invention; 
     FIG. 6 is a schematic representation of the structure and operation of an individual ice pocket of the ice tray of the present invention; and 
     FIG. 7 is a schematic representation of a transverse view of one of the pockets of the ice tray of the present invention, to illustrate the dimensional relationships within the pocket. 
    
    
     DETAILED DESCRIPTION 
     As shown in FIG. 1, the ice tray 11 is formed of a thin, substantially flat, horizontally arranged sheet 13 of relatively stiff plastic-like material of substantially uniform thickness throughout which can be twisted and bent resiliently upon the application of suitable manual forces and which will resiliently return to its original shape. A number of suitable plastics are commercially available for this purpose, such as some of the vinyl formulations, polyvinyl chlorides, etc. The particular plastic selected is within the realm of those skilled in the art. 
     Sheet 13 is generally rectangular in shape and has a first longitudinal axis 15 and a second transverse axis 17 which is perpendicular to the first mentioned axis 15. 
     A pair of parallel rows of individual cavities, compartments or cells are formed in the sheet 13 and arranged in parallel relation to the first axis 15. Each cavity 19 is adapted to receive water or other liquid to be frozen. Each cavity 19 presents a top opening 21 defined by the upper edges or margins of such cavity meeting the horizontally disposed interconnecting top wall portion, angularly and presents a degree of sharpness as revealed particularly by FIGS. 6 and 7 of the drawings and includes a continuously uniformly curved bottom wall portion 23 flanked by a pair of opposed concave side walls 25, of generally part conical configuration inclined upwardly and outwardly. 
     The top opening 21 of each of the cavities 19 has generally hexagonal perimetral configuration and each has longitudinal axis 27 and a transverse or width axis 29. A pivot axis 31 is parallel to the transverse axis 29 and perpendicular to the longitudinal axis 27 and is located across the central portion of the opening 21 between the opposed apices of the side walls 25. The pivot axis 31 longitudinally bisects the opening 21 and the transverse width of the top opening 21 measured along the pivot axis is the maximum width dimension (Wmax) of the top opening 21 while the transverse width measured parallel to the pivot axis at the ends of the opening 21 is a minimum width dimension (Wmin). 
     Pivot axis 31 in the preferred embodiment lies substantially in the plane of the top or access opening 21 which is coincident with the plane of the sheet 13 constituting the top wall of the ice tray. 
     Obviously by placing the pivot axis or center of curvature 31 in the plane of the top wall, a maximum volume of ice piece is achieved, whereby the bottom wall extends throughout 180°. If the pivot axis 31 should be placed in the region above the plane of the top wall, the angular extent of the bottom wall will be reduced below 180° whereby the volume of the ice piece will be diminished. 
     The length of top opening 21 measured along its longitudinal axis 27 is dimensionally greater than the maximum width dimension of the opening 21. The continuously curved bottom wall portion 23 is integral with the sheet 13 and extends downwardly from the opposite longitudinal end portions of top opening 21 in a continuous, generally circular arc having an axis of generation parallel to or coincident with pivot axis 31. In the preferred embodiment disclosed herein, the arc throughout extends 180° or thereabouts the bottom wall 23 is cylindrically shaped and has a transverse width no greater than the minimum transverse width (Wmin) of the opening 21. 
     Each of the pair of opposed side walls 25 is integral with the sheet 13 and extends downwardly from the sides of the top opening 21. Side walls 25 are generally uniformly concaved of part conical configuration tapering downwardly and inwardly until they become integrally merged with the continuously curved bottom wall 23. 
     The angle between each side wall and a bottom wall centrally thereof and measured in a vertical plane is of the order of 105° as may be seen in FIG. 7. This angle of 105° is substantially greater than 90° and is in contrast to small draft angles required for mould removal from dies as set forth in standard texts for specific materials. 
     It will also be readily understood that the bottom wall 23, being uniformly curvate and side walls 25 being uniformly part conical have an axis of generation coincident with pivot axis 31. 
     As shown in FIGS. 1, 2 and 6, the ice tray 11 of the present invention also includes a raised rim portion 33 surrounding the sheet 13. The raised rim portion 33 is integral with the sheet 13 and includes a substantially vertical wall portion 35, a substantially horizontal top portion 37, and a downwardly extending flange portion 39. The substantially vertical wall portion 35 is generally normal to and integral with the sheet 13 and extends upwardly therefrom. The substantially horizontal top portion 37 is integral with the top part of the vertical wall portion 35 and is perpendicular thereto, and it extends away from the sheet 13 and is substantially parallel thereto. The downwardly extending flange portion 39 is integral with the top portion 37 and is substantially parallel to the vertical wall portion 37. 
     A plurality of spaced reinforcing ribs 41 are integral with the vertical wall portion 35, the horizontal top portion 37 and the flange portion 39 and extends therebetween for strengthening the tray 11. 
     Each of the sheets 13 is provided with one or more drain openings or apertures 43 so that water or other liquid poured onto the sheet 13 and generally directed thereon by the raised rim portion 33 will be directed through the openings 21 into the cavities 19. Any excess water over and above that required to fill the cavities 19 will be drained off of the top surface of the sheet 13 through the holes 43. 
     An hourglass-shaped configuration 45 exists between each adjacent pair of longitudinally arranged cavities 19 and a notched channel 47 may be provided across the narrowest portion of the hourglass configuration 45 to allow the flow of liquid between adjacent pockets to provide for level equalization between cavities. 
     As seen in FIG. 2, the ice tray 11 of the present invention may be provided with reinforcing support legs 49. Each of the legs 49 includes an elongated portion 51 which is integral with the underside of the sheet 13 and adjacent side walls 25, and each has a lower end adapted to support the tray level on a horizontal surface. Additionally, a notched portion 53 may be provided at the lower end of the elongated portion 51 for engaging the notched channels 47 or the thinnest portion of the hourglass configuration 45 between the adjacent pockets to allow one tray 11 to be positioned immediately above another tray 11 for compact stacking purposes. The leg portions 53 effectively interlock the compactly stacked trays to prevent slippage while insuring sufficient spacing to prevent interference with formation of ice pieces. 
     Additionally, FIG. 2 shows that a plurality of reinforcing rib-like members 55 may be provided between adjacent cavities 19. These members 55 are integral with the underside of the sheet 13 and the side walls 25 of adjacent pockets 19 for further strengthening the tray 11. 
     FIG. 6 shows how an individual piece of ice 57 presses downwardly with his finger 59 as indicated by the arrow of FIG. 6 causing the individual pieces of ice 57 to slideably rotate about its pivot axis or fulcrum apices 31. This causes the piece of ice 57 to be loosened from the pocket 19 and further finger pressure will slideably eject or remove the piece of ice 57 from the pocket 19. 
     Additionally, since the ice tray 11 is made from substantially rigid yet resilient plastic material and of generally thin uniform thickness throughout a manually applied twisting motion to opposite ends of the tray 11 will loosen all of the individual pieces of ice for simultaneous removal, if desired. 
     In operation, the user holds the tray 11 under a faucet or some similar source of water or liquid and the rim portion 33 insures that the liquid is directed onto the flat surface 13 and then through the openings 21 into the cavities 19. The notched apertures 47 between adjacent cavities insure level equalization of the liquid between pockets 19 when they are filled, and all excess water drains from the surface of the sheet 13 through the drain apertures 43. 
     The tray is then placed within the freezer compartment of the refrigerator and the liquid freezes within the cavities 19. As the liquid freezes, it will freeze over the top of the cavities. The last portion of the liquid to freeze will be a portion adjacent the bottom of the cavities. This last portion of the liquid as it freezes will expand the side walls of the cavities adjacent the bottom wall thereof. 
     When ice is desired, the user removes the tray from the refrigerator and, if all of the pieces of ice are desired, he grasps the tray at opposite ends and twists or slightly bends the tray. This force is transmitted from pocket to pocket via the sheet 13 and the rib-like members 55 thereby loosening each piece of ice from its own cavity or compartment 19. As each piece of ice is loosened from its own cavity, the expanded bottom portion thereof will cause the piece of ice to rise in its own cavity and will prevent the piece of ice from settling down into contact with the bottom wall due to engagement of the expanded portions of the piece of ice with the side walls of its cavity above the area of the side wall which it previously engaged on freezing. Thus, the pieces of ice are loose in the cavity and the cavity is not deformed. The piece of ice therefore remains loosened in its cavity after twisting of the ice cube tray which further promotes arcuate movement of the piece of ice and thus removal from the cavity. 
     If, on the other hand, the user desires a single piece of ice, he merely presses down on one end of a single piece of ice 57, as indicated in FIG. 6, causing it to rotate about its pivot axis 31 for easy individual removal from the cavity 19. 
     With this detailed description of the prime embodiment of the present invention, it will be obvious to those skilled in the art that various modifications may be made in the structure of the ice tray of the present invention without departing from the spriit and scope of the present invention which is limited only by the appended claims.