US3580009A

US3580009A - Ice maker

Info

Publication number: US3580009A
Application number: US790820A
Authority: US
Inventors: Lawrence E Snow
Original assignee: White Consolidated Industries Inc
Current assignee: White Consolidated Industries Inc
Priority date: 1969-01-13
Filing date: 1969-01-13
Publication date: 1971-05-25
Anticipated expiration: 1988-05-25

Abstract

An automatic icemaker in which a flexible ice tray is twisted to loosen the ice cubes by unidirectional rotation of one end of the tray while rotation of the opposite end of the tray is temporarily restrained and a reverse twist force is imparted to the tray by relatively accelerating the other end of the tray before the tray is returned to its normal upright position.

Description

United States Patent Lawrence E. Snow Greenville, Mich.

Jan. 13, 1969 May 25, 1971 White Comolidated Industries, Inc. Greenville. Mich.

Inventor Appl. No. Filed Patented Assignee ICE MAKER 1 Claim, 4 Drawing Figs.

US. Cl 62/353, 62/72 Int. Cl F 25c 1/10 Field of Search 62/72, 353

[5 6] References Cited UNITED STATES PATENTS 3,382,682 5/1968 Frohbieter 62/72 3,056,271 10/1962 De Turk 62/353 3,308,631 3/1967 Kniffin 62/72X Primary ExaminerWilliam E. Wayner Attorney-Strauch, Nolan, Neale, Nies & Kuiz ABSTRACT: An automatic icemaker in which a flexible ice tray is twisted to loosen the ice cubes by unidirectional rotation of one end of the tray while rotation of the opposite end of the tray is temporarily restrained and a reverse twist force is imparted to the tray by relatively accelerating the other end of the tray before the tray is returned to its normal upright posit1on..

Patented May 25, 1971 7 3,580,009

' 5' 4 INVENTOR.

LAWRENCE E. SNOW ICE MAKER Recently automatic icemakers particularly those for use in domestic refrigerators have become increasingly popular. Most, if not all, of these units comprise a single flexible ice tray having a number of molds or pockets which are automatically filled with water which is then frozen. A sensing device or timer then actuates the drive mechanism, which is effective to loosen the ice blocks and the invert or tilt the tray to deposit the iceblocks in a storage bin.,The tray is then returned to its upright position and the cycle is repeated.

Generally the ice trays are made of plastic material which possesses the necessary flexibility to permit the repeated substantial flexing and twisting of the tray required to loosen the ice cubes. While such materials have a high degree of resiliency, nevertheless, after repeated cycling particularly in a very low temperature environment, the tray requires a permanent set in slightly twisted form. Prior proposals to overcome this disadvantage have taken two primary forms. In the first the tray is released from its twisted position with a snap action. An example of this type of construction is disclosed in US. Pat. No. 3,056,271. It has been found, however, that this expedient decreases but by no means eliminates the permanent set taken by the tray.

It has also been proposed to restore its tray to its original shape by positively reversely twisting the trayby reversing the direction of rotation of the driven end of the tray while the remote end of the tray is held against rotation by a mechanical stop. While-this type of construction, an example of which is disclosed in US. Pat. No. 3,217,510, is effective in eliminating the distortion of the tray, nevertheless, it requires a complicated and expensive drive system necessitating the use of gears and cams which are subject to malfunction and wear. Alternately this type of reverse twist action may be effected by providing a bidirectional drive for one end of the tray. This again requires a reversible motor and an associated control circuit which is unduly complex and expensive.

SUMMARY OF THE INVENTION In view of the foregoing background it is the principal purpose and object of the present invention to provide improved icemakers of the typein which a flexible ice tray is twisted to release the iceblocks and improved simplified low cost and yet rugged and reliable means for preventing the attainment of permanent set in the tray.

In accordance with the present invention this and other objects are obtained by the provision of a tray drive system in which one end of the tray is rotated unidirectionally at uniform speed through 360 from a normal upright position through an inverted position in which the iceblocks are loosened and delivered to a storage bin, the tray then being returned to its upright position. As the tray approaches or reaches its inverted position it is twisted in one direction about its longitudinal axis to loosen the iceblocks. Subsequently in the cycle the remote or nondriven end of the tray is accelerated with respect to the driven end of the tray to impart a reverse twist force to the tray to restore it to its original shape. The acceleration of the remote end of the tray is effected by a spring which also serves to retain the remote end of the tray securely in its supporting structure.

The present invention is particularly adapted for use with associated structure such as that disclosed in copending application Ser. No. 790,654 filed on even date herewith for lcemaker and owned by applicants assignee.

Additional objects and advantages will become apparent as the description proceeds in connection with the accompanying drawings.

THE DRAWINGS FIG. 1 is a perspective view of a complete automatic icemaker incorporating the subject matter of the present invention;

FIG. 2 is a top plan view of the tray and associated mechanism; and

FIGS. 3 and 4 are enlarged fragmentary sections taken along lines 3-3 and 4-4 of FIG. 2.

DESCRIPTION OF PREFERRED EMBODIMENT For present purposes the invention will be disclosed as applied to an icemaker of the type disclosed in the aforesaid copending application to which reference may be had for details of construction.

In general the icemaker comprises a U-shaped rigid metal frame 20 adapted to be mounted in the freezer compartment of a refrigerator. The frame assembly comprises a base section 22 and

sidewalls

24 and 26, the free ends of which are secured to a housing 28 containing a unidirectional drive motor and associated control mechanism which may be of conventional construction.

The output shaft 30 of the drive motor is drivingly connected to a fitting 32 carried by one end of an elongated plastic ice tray 34 provided with the usual series of molds or pockets 36 in which the ice blocks are formed. The tray 34 is preferably formed from a flexible plastic such as polypropylene, which is relatively flexible and capable of being subjected to repeated twisting actions about its longitudinal axis without deterioration.

At its opposite end the tray is provided with a rigid plastic fitting 38. Formed integrally with the fitting 38 is a boss having a generally cylindrical section 40, an enlarged annular shoulder 42, and a reduced cylindrical extension 44, all of which are formed coaxially of the motor drive shaft 30. The reduced boss extension 44 is rotatably received in a through bore 46 in a bearing 48 having a peripheral groove 50 in which the portion of the sheet metal base 22 forming the reduced upper portion of a keyhole opening 52 is received.

The parts thus far described may be assembled by first installing the bearing 48 in the enlarged portion of the keyhole opening 52, moving it upwardly to the position shown, and sliding the driven end of the tray onto the shaft 30. The tray is then displaced to the right as viewed in FIG. 2 to dispose the reduced boss extension 44 within the bearing 48.

The parts are held in assembled relation by a wire spring 54 theopposite ends of which are hooked over the upper edges of the frame base 22, the position of the spring being determined by a recess 56 which receives one end of the spring. The spring is held away from the surface of the frame base 22 by a pair of

indentations

58 and 60 struck inwardly from the frame base 22. The main body portion of the spring is thus disposed inwardly of the shoulder 42 and in engagement with the larger boss section 40. It is to be particularly noted that the boss section 40 is provided with a flat 62 of substantial length. When the tray 34 is disposed in its upright position as shown in FIGS. 1 and 2, the flat 62 is disposedat an angle of approximately 5 with respect to the horizontal. The spring 54 is so constructed that it is at all times displaced from its free or relaxed position shown in dotted lines in FIG. 3 so that it exerts a substantial upward force against the boss section 40. This force is increased as the tray is rotated away from its upright position and the spring engages the cylindrical surface of the boss portron.

The operation of the icemaker will now be described, assuming that the tray has been filled with water and that the individual iceblocks have been frozen. A sensor, which may be of conventional construction, then activates the drive motor which rotates the tray in a clockwise direction as viewed in FIG. 3. The spring 54 is immediately deflected downwardly by the cylindrical surface of the boss portion 40. The rotation of the tray is continued until it is substantially inverted at which time a stop surface 64 on the fitting 38 contacts anabutment surface 66 formed on one end of a stop bar 68 slidably carried by the frame member 26.

The rotation of the driven end of the tray continues while the rotation of the remote end of the tray is arrested imparting a substantial, for example, 30 twist which is sulficient to loosen the iceblocks which then fall into a storage receptacle 70 removably mounted on the lower edges of the

side frame members

24 and 26. ln the continued rotation of the driven end of the tray a cam surface 72, formed on the fitting 32, engages a cam surface 74 formed on the slide bar 68 which is then displaced to the left to bring the abutment surface 66 out of registration with the stop surface on the fitting 38. While the tray then tends to resume its original shape it has been found that under repeated flexing, particularly low temperature, the tray tends to take a permanent set in partially twisted form.

This tendency is eliminated by the spring 54 and the associated mechanism as follows. After approximately 325 of rotation the end 62a of the flat 62 contacts the spring 54. lmmediately after this occurs, the spring 62 tends to restore the adjacent end of the tray to its fully upright position. Since the driven end of the tray is rotated at constant speed the remote end of the tray is effectively accelerated, imparting a twist restore the tray to its original shape without imposing any appreciable friction loads on the cylindrical portion of the boss 40.

Thus the foregoing objects of the invention have been achieved by the provision of a mechanically uncomplicated arrangement for restoring the ice tray to its original shape, the mechanism also being utilized to facilitate assembly or disassembly of the ice tray and support structure and to hold the parts in proper relation during all phases of operation.

The invention may be embodied in other specific forms without departing from the spirit or essential characteristics thereof. The present embodiment is therefore to be considered in all respects as illustrative and not restrictive, the scope of the invention being indicated by the appended claims rather than by the foregoing description, and all changes which come within the meaning and range of equivalency of the claims are therefore intended to be embraced therein.

What is claimed and desired to be secured by Letters Patent It is claimed:

1. An automatic ice maker comprising an ice tray mounted in support structure for rotation about a predetermined axis, unidirectional drive means connected to one end of said tray for rotating said tray about said axis in one direction from an upright position through an inverted position and then to said upright position, means for twisting said tray in one direction about said axis during a portion of said rotation, a pivot projecting from said remote end of said tray,said pivot having a first portion rotatable in said support structure, said pivot having a second portion provided with a cylindrical surface interrupted by a flat surface and a spring engageable sequentially with said cylindrical surface and said flat surface, said spring being effective, when engaged with said flat surface, to drive said remote end of said tray in a direction to twist said trayin the opposite direction about said axis.

Claims

1. An automatic ice maker comprising an ice tray mounted in support structure for rotation about a predetermined axis, unidirectional drive means connected to one end of said tray for rotating said tray about said axis in one direction from an upright position through an inverted position and then to said upright position, means for twisting said tray in one direction about said axis during a portion of said rotation, a pivot projecting from said remote end of said tray, said pivot having a first portion rotatable in said support structure, said pivot having a second portion provided with a cylindrical surface interrupted by a flat surface and a spring engageable sequentially with said cylindrical surface and said flat surface, said spring being effective, when engaged with said flat surface, to drive said remote end of said tray in a direction to twist said tray in the opposite direction about said axis.