US 3730488 A
A two-compartment beverage dispenser having a single drive motor and associated drive magnet disposed external of the compartments and a pair of separated driven magnets responsive to rotation of the drive magnet, disposed one in each compartment and each having an impeller associated therewith. The drive magnet is magnetized in one sense, the driven magnets are magnetized in the opposite sense, and the number of pole faces of the drive and driven magnets may be preselected to provide the desired impeller drive speed.
Description (OCR text may contain errors)
United States Patent 1 Gardner, Jr.
MAGNETIC DRIVE COUPLING FOR BEVERAGE DISPENSER Inventor: John A. Gardner, Jr., Tewksbury,
.let Spray Cooler, Inc., Waltham, Mass.
Filed: May 18, 1972 Appl. No.: 254,510
US. Cl ..259/67, 259/D1G. 46, 310/103, 310/104 Int. Cl ..H02k 7/00 Field of Search ..259/DIG. 46, 7, 104, 259/67, 108; 310/93, 101, 103,104
 References Cited UNITED STATES PATENTS 3 1 920 l-lenry ..310 103 1,392,875' 10/1921 Langhans ..259/67 [451 May 1, 1973 2,481,172 9/1949 Staggs ..310/104 X 3,060,702 10/1962 Price, Jr. ....299/l04 X 3,113,228 12/1963 Tolegian..... ....3l0/l04 X 3,510,706 5/1970 Agaba ..310/103 3,523,204 8/1970 Rand ..310/103 X Primary Examiner-D. F. Duggan Attorney-George L. Greenfield et a1.
[5 7 ABSTRACT speed.
16 Claims, 4 Drawing Figures MAGNETIC DRIVE COUPLING FOR BEVERAGE DISPENSER BACKGROUND OF THE INVENTION arrangement including a drive magnet and a pair of responsive driven magnets, each being disposed in a separate compartment of the dispenser. Each of the driven magnets has an impeller associated therewith for circulating the liquid in its associated bowl.
Intercoupled magnet arrangements are commonly used in beverage dispensers to circulate the beverage around a cooling unit and possibly for also pumping the beverage to a vertical spray tube. These known arrangements usually include a drive magnet driven at a predetermined speed and an axially aligned driven magnet having impeller fins associated therewith disposed within the beverage bowl. The drive and driven magnets are magnetized so that they are in locked relationship to each other.
Many of the more recent beverage dispensers include a twin bowl arrangement wherein a pump is disposed in each bowl for circulating the beverage contained therein. In these dispensers there may be provided a common refrigerant compressor and condenser but the drives for the pumps have been provided separately with a drive motor being associated with each bowl. This was thought to be necessary because it did not seem possible to provide a single drive motor and associated drive magnet for operating two driven magnets and yet to keep the drive magnet and driven magnets in the conventional (axially aligned) locked orientation.
Other schemes that were attempted included a belt Accordingly, it is a primary object of the present invention to provide an improved magnetic drive arrangement preferably adapted for use in a twin-bowl beverage dispenser.
Another object of the present invention is to provide a magnetic drive arrangement which, in a preferred embodiment, comprises a motor driven drive magnet disposed external of the dispenser bowls and a pair of driven magnets, one associated with each bowl of a twin-bowl dispenser, and being aligned non-coaxially with relation to the axis of the drive magnet. The driven magnets are disposed preferably at opposite sides of the drive magnet and adjacent to the outer circumference thereof.
A further object of the present invention is to provide a magnetic drive arrangement that is less critical to alignment tolerances than is the case with previously known magnetic drive arrangements.
Still another object of the present invention is to provide a magnetic drive arrangement for use in a beverage dispenser wherein the driven magnets are driven directly from the drive magnet rather by means of secondary driven magnets and associated supports.
Still a further object of the present invention is to provide a magnetic drive arrangement for use with a twin-bowl dispenser that can be constructed more inexpensively than previous magnetic drive arrangements and that is neither noisy nor susceptible to periodic failures. The arrangement of the present invention also enables the fabrication of twin-bowl dispensers of smaller size which is critical for many applications.
SUMMARY OF THE INVENTION To accomplish the foregoing and other objects of the present invention, the magnetic drive arrangement,
which is preferably adapted for use in a twin-bowl beverage dispenser, comprises a magnetic drive means disposed adjacent and external to a wall defining the double bowl of the dispenser, and a pair of magnets, one being disposed in each of the bowls and being responsive to rotation of the magnetic drive means. The magnetic drive means preferably includes a conventional drive motor and associated magnetic drive disc having a plurality of discrete magnetic pole faces disposed about the circumference thereof. Each of the magnets of the pair of driven magnets is disposed inside its respective bowl adjacent the circumference of the magnetic drive disc and also has a plurality of discrete pole faces disposed about its circumference. Both driven magnets are responsive to rotation of the magnetic drive disc for causing like rotation of each driven magnet. Each of the driven magnets has an impeller, or the like, associated therewith for circulating the beverage within its associated bowl and pumping the beverage through a vertical standpipe.
In accordance with one aspect of the present invention the pole faces provided on the drive disc and the pole faces provided on each of the driven magnets may be arranged differently with the number of pole faces being changed depending upon the speed relationship desired between the drive disc and driven magnets. In another embodiment of the present invention the drive magnet is supported for rotation in a first direction and the two driven magnets are supported for rotation in a direction orthogonal thereto. In this embodiment, the pole faces of the magnet drive disc face radially from the disc and the drive disc and driven magnets are arranged perpendicular one to the other. The driven magnets may or may not rotate coaxially.
BRIEF DESCRIPTION OF THE DRAWINGS ing the magnetic drive arrangement of FIG. 1 in a plan view;
FIG. 3 shows a top view of another embodiment for the magnetic drive arrangement depicted in FIG. 2; and FIG. 4 shows another embodiment of the invention wherein the driven magnets are disposed orthogonal to the magnetic drive disc. a
DETAILED DESCRIPTION Referring now to the drawings, and in particular to FIGS. 1 and 2, there is shown a twin-bowl beverage dispenser which generally comprises separate beverage bowls l2 and 14 with their associated circulating pumps 16 and 18, respectively, and magnetic drive means 20. In the embodiment shown in FIGS. 1 and 2 the magnetic drive means is disposed below the beverage bowls. However, in an alternate embodiment, it is possible that the drive means may be coupled to the side or even the top of the beverage bowls.
The beverage contained in the bowls l2 and 14 may be dispensed through discharge ports 22 and 24, respectively (see FIG. 2). The pumps 16 and 18, which are discussed in more detail hereinafter, direct the beverage up their associated standpipes 26 and 28 and also direct the beverage through apertures 30 and 32, respectively, toward cooling evaporators 34 and 36. The evaporators may be of conventional design. The standpipes 26 and 28 normally terminate adjacent the top wall of the beverage bowls and as the beverage is directed up the standpipes and down along the side walls of each bowl there is a certain amount of cooling provided. Also, this type of circulation provides animated display.
The circulating pumps 16 and 18 shown in detail in FIG. 1 are substantially identical in design and the same or similar reference numerals are used hereinafter to designate like parts of these pumps.
Each of the beverage bowls has a cylindrical well 33 surrounded by a shallow ring-shaped depression 35. A circular cap 37, preferably made of molded plastic, is disposed over the well, and the flat rim portion 37A of cap 37, which is seated in depression 35, may be removably fixed within this depression such as by the means shown in US. Pat. No. 3,272,380. A voluteshaped inverted trough 41 is formed in the cap, and the from a slurry by pressing a wet suspension of ferrite particles into the desired shape with a punch in a forming die which thereby results in the fluid of the slurry being substantially removed, leaving a rigid shape which can be removed from the die and handled for subsequent-processing steps. The formed shape is then kiln fired at fusion temperatures, in excess of l200 F., resulting in a cohesive mass of the desired dimensions. Depending upon the application of the magnet, it is then magnetized by subjecting the assembly to a unidirectional electromagnetic field of proper direction and strength to induce a residual magnetization of virtually permanent nature. Generally, for best long-term results and stability the magnet is magnetized to saturation.
FIGS. 1 and 2 show the N-S magnetic pole arrangement necessary to provide the drive for the circulating pumps. The magnetization pattern shown may be provided by spot magnetization or apertures can be provided in the driven discs 44 and drive disc 54 for receiving permanent magnets of generally cylindrical shape disposed at the proper location about the disc. If small permanent magnets are used they are magnetized so that the force field is axial, so that when the magnets are installed in the pockets of the drive disc, for example, the north poles face upwardly toward the driven magnets while the south poles face downwardly as shown in FIG. 1. The discs 44 containing magnet groups 46 and-48 overlap the drive disc 54, as shown, so that the arc of rotation circumscribed by magnets 56 of disc 54 crosses the'arc of rotation circumscribed by magnets 46 and 48. With this arrangement the magnetic flux generated by the individual magnets 56 of disc 54, which total four in the embodiment shown in FIGS. 1 and 2, can influence the corresponding magcap includes intake port 42 communicating with this trough.
The cap 37 has an upstanding handleportion 37B by which it may be grasped and turned for removal. A metal shaft 43 is fixed in the handle portion, for example, by molding or pressing the shaft into the cap material. A circular magnetic drive disc 44 is rotatably suspended on the shaft and carries pump vanes 45 which are disposed in trough 41. The disc 44 is preferably made of molded plastic and has a plurality of discrete magnets 46 encased therein. FIG. 1 shows one group of magnets 46 used in the disc of pump 16 and a like group of magnets 48 used in the disc of pump 18. In the disclosed embodiment each of the magnets is disposed with its south (s) pole facing drive means 20. The cap 37 has a discharge opening 47 communicating with trough 41, surrounded by a nipple 49 in which the standpipes 26 or 28 are mounted.
The drive means 20 includes a motor 50 which may be of conventional design and includes an output drive shaft 52. A magnetic drive disc 54 is suitably supported at its central axis on drive shaft 52. The magnetic drive means 20 is suitably supported so that the discrete magnets 56 are disposed directly under and close to the magnets 46 and 48. The groups of magnets 46 and 48, and group 56 may be either of metallic or ceramic composition and have pole faces, as indicated, directed toward one another. In a preferred embodiment ceramic magnets are used. The ceramic magnet is formed nets 46 and 48 of the driven discs 44 to the fullest extent. Typically, with disc 54 at rest, discs 44 rotate until one of the magnets of both driven discs line up vertically with a corresponding magnet of disc 54, as shown in FIG. 2
The gap between the magnets of the drive and driven discs is determined experimentally for best performance of the i drive within the confines of the geometry of the particular dispenser. lnsome cases the magnetic materials may have to be changed to a higher 'or lower field strength material to satisfy the needs of the system for-higher or lower output power, from the d'rivendiscs. I
In the static position shown in FIG. 2 the drive and driven discs are in locked relative relationship. How
ever, once the drive disc 54 begins to rotate, magnets 46 and 48 are attracted by the movement of magnets 56 and thus discs 44 rotate maintaining all discs in a locked configuration. As disc 54 turns about its center it is seen in FIG. 2, in particular, that the arc of rotation of the magnets 56 goes beyond the zone of attraction for the corresponding magnets 46 and 48, and thus the magnets 46 and 48 free-spin momentarily due to the impact of momentum provided by magnet 56. This spinning is continuous until the next magnet 56 aligns with the next magnets 46 and 48, and the attractive forces of the magnetic coupling come into play. The successive pairs, coupled during rotation, serve to build up the speed of the driven discs until a synchronous speed is established between the drive and driven discs.
Speed measurements taken with a stroboscope have shown that with a motor speed of 1400 rpm, the driven discs are operated at a slave speed of 1400 rpm with the particular arrangement shown in FIG. 2. In the configuration of FIG. 2 where these driven discs form part of 5 the impeller of a centrifugal pump, force measurements taken to determine the stall force necessary to stop one of the slave magnets indicated a 3-lbs. force was required.
FIG. 3 shows diagrammatically another arrangement for the drive disc 54 and driven discs 44. The driven discs may be identical to those shown in FIG. 2, each including four magnets 46 or 48 disposed about the circumference of the disc at 90 intervals. The drive disc 54 is similar to the one shown in FIG. 2 but has eight magnets 56 disposed thereabout at 45 intervals. With this arrangement both driven discs operate dynamically at twice the synchronous speed of the drive disc. From this alternate embodiment it is readily seen that many other embodiments can be devised for providing other speed relationships between drive and driven discs.
FIG. 4 shows an alternate structural arrangement in accordance with this invention including a drive disc 60 and driven discs 62 and 64. FIG. 4 also shows a partial section of a beverage bowl 66 having an indented portion 68 for accommodating the drive disc. The drive disc is operated from a motor 70 via an interconnecting shaft 72 coupled to the central axis of the drive disc. A group of magnets 74, which may total four, are disposed about the circumference of the disc with their north poles facing radially of the disc. The driven discs 62 and 64 are suitably supported for rotation within bowl 66 on shafts'76 and 78, respectively. The shafts 76 and 78 are disposed in coaxial relationship and are both disposed orthogonalto shaft 72. Thus discs 62 and 64 are perpendicular to disc 68. However, in an alternate embodiment discs 62 and 64 can be slanted relative to drive disc 60.
The driven discs 62 and 64 may be the same as discs 44 of FIG. 2, each including four discrete magnets 78 having their south poles directed toward the drive disc. When in a locked configuration, as shown in FIG. 4, the magnets 74 and 78 are aligned, and as disc 60 rotates, discs 62 and 64 follow disc 60 in a similar manner as previously discussed with reference to FIGS. 1 and 2. The speed control concepts hereinbefore discussed can also be applied to the embodiment of FIG. 4 by varying the number of discrete magnets used.
Having described a limited number of embodiments of the present invention, it should now be obvious that numerous other embodiments will fall within the scope of the present invention which is defined by the follow ing claims.
What is claimed is: 1. A magnetic drive arrangement for use in a double bowl beverage dispenser comprising:
magnetic drive means disposed external of said double bowl and adjacent to a wall defining the double bowl, first magnet means disposed within one bowl, operatively positioned adjacent an outer portion of the magnetic drive means, and movable in response to movement of said magnetic drive means, and second magnet means disposed within another bowl, operatively positioned adjacent an outer portion of the magnetic drive means spaced from the first magnet means, and movable in response to movement of said magnetic drive means,
both said first and second magnet means having liquid circulating means associated therewith.
2. The arrangement of claim 1 wherein said magnetic drive means comprises a drive disc having means defining a plurality of spaced pole faces.
3. The arrangement of claim 2 wherein said means defining a plurality of pole faces includes discrete permanent magnets disposed about the outer circumference of the disc.
4. The arrangement of claim 3 wherein the magnets have their north-south poles aligned orthogonally to the plane of the disc.
5. The arrangement of claim 4 wherein said magnetic drive means further comprises a drive motor and shaft intercoupling the drive motor and drive disc.
6. The arrangement of claim 5 wherein the first and second magnet means each comprise a driven disc having a plurality of discrete magnets disposed about the outer circumference of the disc.
7. The arrangement of claim 6 wherein the driven discs are supported for rotation with their outer circumference disposed adjacent the outer circumference of the drive disc so that one magnet of each driven disc aligns with opposite magnets of the drive disc when the drive and driven discs are in locked relationship.
8. The arrangement of claim 7 wherein the supporting means for both the drive disc and driven discs are all parallel to each other but not coaxially arranged.
9. The arrangement of claim 1 wherein said magnetic drive means comprises a drive disc having a plurality of spaced magnets associated therewith disposed about the circumference of the drive disc, and said first and second magnet means each comprise a driven disc having a plurality of spaced magnets associated therewith disposed about the circumference of the driven disc.
10. The arrangement of claim 9 wherein said driven discs are aligned in a like plane and are supported spaced from each other.
11. The arrangement of claim 10 wherein the drive disc and driven discs are disposed so that one magnet of the first magnet means aligns in attracting relationship with a magnet of the drive disc, and one magnet of the second magnet means aligns in attracting relationship with another magnet of the drive disc when in locked relationship. I
12. The arrangement of claim 11 wherein the magnets of the drive disc that are alignable are oppositely disposed magnets.
13. The arrangement of claim 9 wherein the same number of magnets are associated with the drive disc and each driven disc.
14. The arrangement of claim 9 wherein a different number of magnets are associated with the drive disc and each driven disc.
15. The arrangement of claim 9 wherein said drivendrive disc, and one magnet of the second magnet means aligns in attracting relationship with another magnet of the drive disc when in locked relationship.