Abstract:
A coffee grinder assembly with a housing containing a pair of hoppers for containing coffee beans with a pair of hopper outlet chutes, or grinding chamber inlet chutes for feeding beans into a grinding chamber where the beans are ground by powered grinding discs or blades and then passed to a removable brew basket via an outlet chute with an outlet end that is in communication with a negative ion generator that ionizes the air in the outlet chute through which the ground coffee and chaff pass on their way to the brew basket to electrically neutralize the chaff to reduce chaff dispersion due to electrostatic repulsion of positively charged chaff.

Description:
This application claims benefit to United States Provisional Application No. 60/200,039 filed Apr. 27, 2000 under 35 USC 119(e). 
    
    
     BACKGROUND OF THE INVENTION 
     1. Field of the Invention 
     This invention relates generally to coffee grinders and, more specifically, to electrically powered grinders that employ rapidly rotating grinding discs. 
     2. Discussion of the Prior Art 
     Electrical coffee grinders of the type that have grinding wheels that operate a high speed are well known in art. Reference may be made to co-pending PCT application serial number PCT/US00/11379 filed Apr. 28, 2000 and entitled “Coffee Grinder with Removable Ingredient Hopper and Method”, which is hereby incorporated by reference for some of the details of such grinders. Briefly, they include a hopper containing the coffee beans and having an outlet with an electrically controlled gate. When the outlet gate is opened, the coffee beans pass through the outlet and into a grinding chamber within which are contained a set of intermeshing grinding discs or wheels that are driven in rotation by an electrical motor. The ground coffee then passes out of the grinding chamber and through an outlet chute and into a suitable container or into a brew basket with a filter paper to hold the ground coffee. The discs are preferably made of ceramic but others are made of stainless steel. 
     A problem with such grinders is often small particles of the ground coffee known as chaff, chaff fines, or fines, fly out of the chute and misses the filter within the brew basket or other container. It escapes from the top of the brew basket even though pressed against the grinder housing. The chaff flies through the air and eventually lands on the outside surfaces of the grinder housing, the brew basket, the counter tops and the floors and wall in the vicinity of the grinder. Although most of the ground coffee makes it into the filter paper within the brew basket, over time the grounds that do not make it into the filter accumulate and must be cleaned up. In addition to making a mess, the loose coffee grounds are wasted. 
     It is believed by the present inventor that this problem is caused or exasperated by the grinding action of the grinding discs with the ground coffee causing a positive static charge being built up on the individual fine particles of ground coffee, or chaff. As a result of the static charge being all of the same polarity, the charged chaff particles are repelled from one another, from the coffee grounds that are in the brew basket and generally from any other positively charged surfaces. It is believed that this is why there is not a smooth flow of the ground coffee including the chaff in a contained stream from the outlet chute without dispersion of the chaff particle outside of the stream. 
     SUMMARY OF THE INVENTION 
     In accordance with the present invention, the aforementioned problem of loose chaff is overcome by artificially creating a source of negative ions through which the positively charged chaff must pass to neutralize the chaff before passing from the outlet chute. 
     This objective is achieved in part by providing a coffee grinder having housing containing a hopper for storage of coffee beans to be ground, a grinding chamber with a set of intermeshing grinding discs, a hopper outlet gate for selectively passing coffee beans from the hopper to the grinding chamber to be ground by the set of intermeshing grinding discs, and an outlet chute for passing the ground coffee out of the grinding chamber, with a chaff dispersion reducing apparatus having means for artificially creating negatively charged ions within the housing and means for passing the negatively charged ions into contact with chaff produced during the grinding of the coffee beans to neutralize the chaff before leaving the housing. Preferably, the ion creating means creates ions in the outlet chute while the emitter is mounted in communication with the interior of the outlet chute adjacent an open, outlet end of the outlet chute. 
     Preferably, the generating means is a negative ion generator that functions to ionize ambient atoms of air to give them a negative charge. The negative ion generator has an emitter, and means for producing an electrical charge on the emitter having a voltage sufficiently high to emit large quantities of electrons to negatively ionize the air. The producing means includes a D.C. power supply for producing a low current, high voltage D.C. voltage on the emitter connected with a source of A.C. power. Preferably, the voltage is on the order of 8400-volts. A ion generator power supply located within the housing and outside of the interior produces the high voltage and a power lead extending to the emitter is mounted in communication with the interior of the outlet chute. 
     The objective of the invention is also obtained in part by providing in a coffee grinder having housing containing a hopper for storage of coffee beans to be ground, a grinding chamber with a set of intermeshing grinding discs, a hopper outlet gate for selectively passing coffee beans from the hopper to the grinding chamber to be ground by the set of intermeshing grinding discs, and an outlet chute for passing the ground coffee out of the grinding chamber with a method of reducing chaff dispersion and to enhance the controlled flow of chaff out of the outlet chute by performing the steps of artificially creating negatively charged ions within the housing, and passing the chaff into contact with the negatively charged ions before the chaff passes out of the outlet chute to electrically neutralize the chaff. 
     The objective is also obtained by providing a coffee grinder having housing containing a hopper for storage of coffee beans to be ground, a grinding chamber with a set of intermeshing grinding discs, a hopper outlet, gate for selectively passing coffee beans from the hopper to the grinding chamber to be ground by the set of intermeshing grinding discs with a chaff dispersion reducing apparatus having means for artificially creating negatively charged ions, and means for passing the ground coffee and chaff through the negatively charged ions to neutralize the chaff. 
     Preferably, the coffee grinder includes an outlet chute for passing ground coffee from the grinding chamber to a brew basket with a outlet pipe for passing the ground coffee from the grinding chamber to the brew basket, and an insulating collar surrounding the metal outlet pipe and in which said creating means creates negatively charged ions within the collar and beneath an outlet end of the outlet pipe. The insulated collar has a bottom with a downwardly facing annular groove surrounding the outlet pipe and in which the creating means creates negatively charged ions within the annular groove. The emitter extends from an emitter body contained within a mounting hole in the collar into the groove to create ions within the groove and beneath a bottom outlet end of the outlet pipe. The grinder has means for mounting an open top of a brew basket against a bottom of the collar and the ions are created beneath the bottom of the outlet pipe and within the brew basket, the brew basket retarding dispersion of the ions to areas through which the chaff does not pass. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     The forgoing objects and advantageous features of the invention will be explained in greater detail and others will be made apparent from the detailed description of the preferred embodiment of the present invention that is given with reference to the several figures of the drawing, in which: 
     FIG. 1 is front elevation view of a preferred embodiment of grinder of the invention; 
     FIG. 2 is a front elevation schematic illustration of one form of the grinder of FIG. 1 with portions cut away for a view of the interior components including the negative ion generator; 
     FIG. 3 is side view of the grinder of FIGS. 2 with portions broken to provide a side view the interior components; 
     FIG. 4 is a functional block diagram of the negative ion generator of FIGS. 2 and 3, and of FIG. 5 below; and 
     FIG. 5 is a side elevation, with parts in cross section of a novel outlet chute illustrating an alternative and preferred form of the invention. 
    
    
     DESCRIPTION OF THE PREFERRED EMBODIMENT 
     Referring now to FIG. 1, the preferred embodiment of the chaff reducing grinder assembly  10  for grinding a food ingredient, and more specifically coffee beans, is seen to have a housing  12  with a control panel  14 , a pair of ingredient hoppers  16  and  18  in which are stored coffee beans or the like, a removable brew basket mount  20  for removably mounting a brew basket  22  beneath an outlet chute  36  to receive the ground coffee. The housing  12  has a base  13  with legs for supporting the grinder  10  above a counter top  15 . 
     Referring now to FIGS. 2 and 3, grinding chamber inlet chutes, or hopper outlet chutes,  24  and  26  extend downwardly from the bottoms of the hoppers  16  and  18 , respectively, to a juncture  28  that then feeds the coffee beans into a grinding chamber  30  that is used for both hoppers  14 . Powered grinding blades (not shown) within the chamber are driven by an electrical motor  32 . At the bottom of the grinding chamber  30  is an outlet chute  36  that directs the ground coffee from an inlet  36  at the bottom outlet of the grinding chamber  30  to an open chute outlet  38 . 
     Referring to FIG. 2 and 3, in accordance with the invention, a negative ion generator  40  is located within the housing  12  and generates negative ions into the air within an ion chamber  42  that is in air communication with the interior of the outlet chute through an ionized air tube  44 . The movement of the ground coffee passing through the chute  36  creates a partial vacuum that draws the ionized air from the ion chamber  42  and through the ion tube and into the chute  36  to neutralize the positive static charges on the coffee being passed through the chute  36 . The ion generator is a Model G1785 negative ion generator distributed by ELECTRONIC GOLDMINE. Alternatively and preferably, the ion generator is a Model SW750, 120 VAC, 60-Hz negative ion generator with a maximum output voltage of 8.4-kvolt made by Seawise Industrial Ltd. of Kowloon, Hong Kong. Ion generators with higher voltages such as 12.4-kvolt Model SW1200 could also be used but it is not believed that higher voltages are needed. Lower voltages may be possible but this needs to be determined individually for the particular dimensions of each particular grinder being made with an anti-dispersion system. The ion generator  40  is powered by standard 115VAC electrical power that is switched to the ion generator  40  whenever the grinder motor  32  receives power. Alternatively, the power to the ion generator remains on at all times. 
     Referring to FIG. 4, the ion generator  40  is seen to include an A.C. power connector  50  for connection to a 115-volt power source and a D.C. power supply  52  that produces a voltage of approximately negative 8.6-kilovolts at a very low current. This high voltage is applied to the end of at least one emitter  54  connected to the power supply via an insulated lead  56 . The power supply  52  and A.C. power connector  50  and insulated lead  56 . The A.C. power supply  50  is contained within a housing  58  and the A.C. power connector leads  50  are connected within and extend outside of the housing  56 . 
     In the embodiment shown in FIGS. 2 and 3, the ion generator  40  is substantially sealed within the ion chamber  42  to protect the circuitry, etc. against contact with the coffee itself and the oils from the coffee. Suitable filter material may be placed into the ionized air tube that will allow the passage of ionized air into the outlet chute or the grinding chamber but which will not allow coffee particles or coffee oil to pass the other way and contaminate the ion generator  40 . If desired a fan may be added to draw the ionized air from the ion chamber  42  into the outlet chute  36  and beneath the outlet chute  36  within the brew basket  22 . 
     While the embodiment shown in FIGS. 2 and 3 in which one or more emitters  54  are contained within the ion chamber  40  and the ions are transported from the ion chamber  42  to the outlet chute  36  via ionized air tube  44  is capable of passing ions into the interior outlet chute  36  and help reduce chaff dispersion, an alternative and preferred, although more perhaps more complicated embodiment is shown in FIG.  4 . 
     Referring to FIG. 4, the outlet chute  36  includes a stainless steel cylindrical outlet pipe  57 , preferably 303-stainless or 304-stainless, having a half-inch diameter and a length of 1½ inches though which the grounds and an insulated collar  58 . The outlet pipe  36  is surrounded by the insulating collar  58  which is preferably made from PTFE TEFLON®. The insulating collar  58  has a generally truncated conical shape with an interior that expands outwardly from the outlet end of the outlet pipe  57  to adjacent the edges  60  of the open top of the brew basket  22 . The bottom  62  of the collar  58  extends beneath the bottom of the outlet pipe  57 . 
     Formed in the bottom  68  of the collar  58  is an arcuate, downwardly facing, annular groove or ion passageway  62  that surrounds the bottom of the outlet pipe  57  and communicates with the bottom of the outlet chute  36  which coincides with and is defined by the bottom  68  of the collar  58 . The annular ion passageway  62  has an interior edge  64  that is level with and adjacent to the bottom of the outlet pipe  57 . An outer edge  66  is located level with the bottom  68  of the collar  58  and located inwardly from the outer edge  60  of the brew basket  22 . 
     Extending into a top  70  of the annular groove  62  from an annular shoulder  72  is at least one emitter mounting hole within which is snugly received an emitter  54 . The emitter  54 ′ has a pointed end  74 , having a point like a sharpened pencil, and an elongate body that substantial fills the mounting hole to seal it closed. An annular access grove  76  in the shoulder  72  surrounds the mounting hole to enable grasping an end of the emitter  54 ′ extending upwardly out of the mounting hole to facilitate mounting and removal of the emitter  54 ′. The insulated lead  56  is fitted into a hole in the end the emitter  54 ′, that is preferably made of a solid cylinder of stainless steel, and soldered in place. 
     It has been found that the ions circulate within the annular ion passageway  62 , beneath the bottom of the outlet pipe  57  within the insulating collar  58  and also beneath the outlet pipe  57  but within the outlet chute beneath the outlet pipe  57  and also within the brew basket  22  between the bottom  68  of the collar  58  and the top  78  of ingredient contained within the brew basket  22 . The close or snug fit of the top edge of the brew basket  22  against the bottom  68  of the collar  58  traps the ions in the space beneath the outlet pipe  57  through which the ground coffee and the chaff must pass. The annular grove  62  filled with ions surrounds the chaff and neutralizes any that moves laterally from the bottom of the outlet chute  36  to the outer edges  60  of the top of the brew basket  22  and thereby prevent their escape. 
     While additional emitters  54 ′ may be added at other locations around the circumference of the annular ion passageway  62 , it has been found that a single emitter with the, voltage indicated above is sufficient. Also, the embodiment of FIG. 5 can be combined with that of FIGS. 2 and 3 to provide ions both in the outlet pipe  57 , as in FIGS. 2 and 3, in which the entire outlet chute functions as the outlet pipe, as well as providing them beneath the outlet pipe but within the outlet chute  57  as well as beneath the outlet pipe  57  and within the space between the bottom  68  of the chute  36  and collar  58  and the top  78  of the ground ingredient within the brew basket. 
     While particular embodiments have been disclosed in detail, it should be appreciated that many variations may be made with respect to these details without departing from the scope of the invention as defined in the appended claims.