Abstract:
A cordless electric dual condiment grinder includes a hollow housing elongated to extend between a base for supporting the grinder uprightly and an opposing top, the top of the housing having a bulbous form to define two condiment reservoirs (e.g. for receiving salt and pepper respectively). A unidirectional rotary grinding mechanism is disposed in a lateral opening in each of the reservoirs. The lateral openings are on opposing sides of the housing and a tilt switch controls the direction of rotation of a reversible drive motor. One-way clutches in the transmission are provided such that each grinding mechanism is selectively rotated depending upon the direction of rotation of the motor output. The user can thus selectively dispense from one or other of the compartments by rotating the grinder through an acute angle from the upright such that the selected lateral opening faces downwardly and thus is particularly suited for use by people with limited dexterity.

Description:
TECHNICAL FIELD 
   The present invention relates to grinders for dispensing two ground condiments, such as pepper and salt, and particularly to grinders driven by electric motors 
   BACKGROUND OF THE INVENTION 
   Hand-held cordless electric grinders provide a convenient and fast method for dispensing freshly ground pepper, salt, or other condiments. A conventional grinder of this type has an elongate housing which defines a grip by which the grinder is held and which has first and second longitudinally opposing ends. A battery compartment at the first end of the housing provides power to an electric motor connected via a speed reduction geartrain to a drive shaft. The drive shaft extends through a condiment reservoir to a grinding mechanism at the second end of the housing. In an upright design the second end may be supported on a table, or a like horizontal surface, when not in use. However, a drawback of this is that, following use, the impact caused by placing the grinder upon a table tends to dislodge condiment particles from or through the grinding mechanism which drop from the grinder and, for instance, may soil a table cloth. 
   An inverted design is therefore preferable, in which the first end is adapted to be supported upon the table so that the second end is uppermost and a recess is provided in the housing to catch any particles dislodged following use. However, an inverted grinder of this type has ergonomic drawbacks as it is necessary to rotate the grinder approximately 180° to dispense the ground condiment and this can be troublesome for people having reduced mobility of the forearm and wrist. Moreover, operating a switch to initiate grinding at the same time as rotating the grinder in this manner can pose further difficulties to disabled people. One object of the invention is to provide a condiment grinder which addresses these drawbacks. 
   There is a continuing need for and interest in improvements to electric condiment grinders of this type. In particular there is a need for a grinder able to selectively dispense two freshly-ground condiments. The grinder should have an efficient geartrain with a low weight and inertia and which can be readily installed. It should also be compact with coaxial drive and driven shafts, relatively efficient and quiet in operation, while being able to operate at high motor speeds. It is a further object of the present invention to address the above needs or more generally to provide an improved condiment grinder. 
   DISCLOSURE OF THE INVENTION 
   According to one aspect of the present invention there is provided a dual condiment grinder comprising: 
   a hollow housing elongated to extend between a base for supporting the grinder uprightly and an opposing top, the top of the housing defining first and second condiment-receiving reservoirs; 
   a filling opening in each reservoir for loading condiment; 
   a lateral opening in each reservoir, each opening extending laterally of the housing; 
   an electric motor within the housing; 
   a battery holder within the housing, the battery holder having contacts for engaging the terminals of batteries received therein; 
   a switch electrically connected to the contacts for selectively supplying power to the motor; 
   a first and second rotary grinding mechanisms for grinding the condiment, each grinding mechanism being disposed in the lateral opening of a respective one of the reservoirs to dispense ground condiment therethrough, and 
   drive means for transmitting torque from the motor to each grinding mechanism. 
   Preferably the top and the base of the housing are relatively broad and are separated by a waist portion adapted to provide a grip for holding the grinder, the base has a planar surface for supporting the grinder upright and the top has a convex surface. 
   Preferably a recess in the housing extends about each lateral opening, each recess having peripheral walls, each grinding mechanism being completely recessed within the housing and a lower section of each of the peripheral walls being upwardly concave to catch any condiment particles dislodged from or through the grinding mechanisms when the grinder is generally upright. 
   Preferably the switch is a tilt switch for automatically actuating the motor when the grinder is tilted from an upright position to direct the lateral opening downwardly. 
   Preferably the grinding mechanism includes a rotor and stator cooperating for grinding the condiment therebetween, the stator being fixed in the lateral opening, the rotor being mounted to a drive shaft extending through the reservoir, the transmission means includes an epicyclic geartrain driven by the motor and a bevel gear pair connected between the epicyclic geartrain and the drive shaft. Preferably the motor and epicyclic geartrain are generally disposed within the waist portion. 
   Preferably one bevel gear of the bevel gear pair, the epicyclic geartrain and an output shaft of the motor are coaxial with a first axis, the first axis being inclined acutely to a longitudinal axis of the waist portion and the other bevel gear of the bevel gear pair is coaxial with the drive shaft to rotate about a second axis orthogonal to the first axis. 
   Preferably the epicyclic geartrain includes a plurality of spur gear epicyclic gearsets, each gearset comprising planet gears meshed with a sun gear, the planet gears of each gearset supported upon a planet carrier, the gearsets stacked within a common ring gear with the sun gears coaxial, adjacent sun gears and planet carriers of adjacent gearsets being rotationally fast for transmitting torque between the adjacent gearsets. 
   In another aspect the invention provides a dual condiment grinder comprising: 
   a hollow housing elongated to extend between a base for supporting the grinder uprightly and an opposing top, the top of the housing defining first and second condiment-receiving reservoirs; 
   an upper opening in each reservoir for loading condiment; 
   a lateral opening in each reservoir, the lateral openings extending laterally from opposing sides of the housing; 
   a reversible electric motor within the housing; 
   a battery holder within the housing, the battery holder having contacts for engaging the terminals of batteries received therein; 
   switch means electrically connected to the contacts for supplying power to the motor to selectively drive the motor in opposing directions; 
   a first and second rotary grinding mechanisms for grinding the condiment, each grinding mechanism being disposed in the lateral opening of a respective one of the compartments to dispense ground condiment through the lateral opening; 
   first and second shafts mounted for rotation about a first transverse axis, each shaft having an outer end fixedly attached to one of the grinding mechanisms and extending inwardly through a respective reservoir, 
   first and second bevel gears mounted for rotation about the first transverse axis; 
   first and second one-way clutch means, the first one-way clutch means connected between the first bevel gear and the first shaft for transmitting torque to the first grinding mechanism, the second one-way clutch means connected between the second bevel gear and the second shaft for transmitting torque to the second grinding mechanism;
 
a third bevel gear meshed with the first and second bevel gears, and
 
a geartrain driven by the motor and connected in driving engagement with the third bevel gear such that rotation of the motor in one direction rotates the first grinding mechanism, while the second grinding mechanism is stationary, and rotation of the motor in a direction opposite to the one direction rotates the second grinding mechanism, while the first grinding mechanism is stationary.
 
   Preferably each grinding mechanism includes a rotor and stator cooperating for grinding the condiment therebetween, each stator being fixed in a respective one of the lateral openings with each rotor being driven by one of the first and second shafts. 
   Preferably the switch means includes a double-pole, double-throw tilt switch for selectively controlling the motor direction and which is capable of detecting a change in orientation on a second transverse axis substantially orthogonal to the first transverse axis. Preferably the double-pole, double-throw tilt switch is a pendulum type centre-off switch. Optionally any other suitable tilt sensing device may be used in the tilt switch, including but not limited to one more tilt switches of the mercury type, ball type, solid state, liquid filled, or electrolytic type. 
   Preferably the switch means further includes a single-pole, single-throw tilt switch electrically connected in series with the double-pole, double-throw tilt switch. Preferably the single-pole, single-throw tilt switch includes a transistor operated by the single-pole, single-throw tilt switch such that the motor current substantially passes through the transistor. Preferably the double-pole, double-throw tilt switch is adapted to operate when the grinder is inclined from its upright position about the second transverse axis by a first angle and the single-pole, single-throw tilt switch is adapted to operate when the grinder is inclined from its upright position about the second transverse axis by a second angle which exceeds the first angle. 
   This invention provides a dual condiment grinder which is ergonomically efficient in operational use. It is particularly well-suited to use by people having reduced dexterity or mobility of the forearm and wrist, who are able to operate the grinder simply by grasping and rotating it through a small angle, typically one way to dispense salt, and the other to dispense pepper. Moreover this is achieved with a design able to catch any condiment particles dislodged from or through the grinding mechanism when the grinder is generally upright. It has a simple construction employing a number of common parts for reduced manufacturing costs. It includes modular components with a low weight and inertia, it is compact, relatively efficient and quiet in operation, and is able to operate at high motor speeds. 

   
     BRIEF DESCRIPTION OF THE DRAWINGS 
     Preferred forms of the present invention will now be described by way of example with reference to the accompanying drawings, wherein: 
       FIG. 1  is a side elevation of an exemplary embodiment of the grinder of the invention; 
       FIG. 2  is a schematic central longitudinal cross section along line CC of  FIG. 1 ; 
       FIG. 3  is a transverse cross section along line AA of  FIG. 2 ; 
       FIG. 4  is a schematic of the gear train of the grinder of  FIG. 1 ; 
       FIG. 5  is an exploded pictorial view of the grinder of  FIG. 1 , and 
       FIG. 6  is a schematic electrical circuit drawing of the grinder of  FIG. 1 . 
   

   DESCRIPTION OF THE PREFERRED EMBODIMENTS 
   Referring to  FIGS. 1-5  of the drawings, a hand-held cordless electric dual condiment grinder according to an exemplary embodiment of the invention includes a hollow housing  10  having a substantially symmetrical waisted form, with an elongate waist portion  11  which provides a grip for holding the grinder. The waist portion  11  separates the base  12  from the top  13  which both have relatively broader dimensions. The base  12  has a planar face  14  for supporting the grinder upright on a horizontal surface, the face  14  extending orthogonally to a longitudinal upright axis  15  of the waist portion  11 . The hollow waisted housing  10  is assembled from two T-shaped shells  10   a ,  10   b  having a bulbous top  13  with convex top surface  47  and opposing lateral openings  41   a ,  41   b  aligned with a first transverse axis  48 . Disposed in the top  13  either side of the axis  15  are first and second condiment-receiving reservoirs  27   a ,  27   b  bounded externally by the housing walls and internally by the transverse wall  29  and the longitudinally extending wall  49 . Upper openings  44   a ,  44   b  in the reservoirs  27   a ,  27   b  are provided for loading condiment and are closed by respective hinged closures  45   a ,  45   b.    
   A battery holder  16  is provided in the housing  10  below a reversible electric motor  17  having an shaft rotating about the drive axis  15 . The battery holder  16  has contacts  40  for abutting the battery terminals (not shown). The battery holder  16  and motor  17  are fixed inside a tubular mounting assembly  19 , to one axial end of which the battery holder  16  is fixed. The battery holder  16  is located near the base  12 , such that with batteries in place the centre of gravity is lowered for stability. 
   Mounted to the battery holder  16  are a ball-type tilt switch  20  and a pendulum-type double-pole, double-throw (DPDT) tilt switch  70  which are electrically connected in a circuit (see  FIG. 6 ) between the contacts  40  and the motor  17  to control direction in which the motor output shaft is rotated, depending upon the inclination of the grinder. 
   An epicyclic geartrain  21  driven by the motor  17  supplies torque through a shaft  22  to a bevel gear  23 . The shaft  22 , bevel gear  23  and geartrain  21  are coaxial with the axis  15 . The bevel gear  23  is meshed with gears  57 ,  60  to transmit the torque through 90° to drive shafts  25   a ,  25   b  extending through respective condiment-receiving reservoirs  27   a ,  27   b.    
   The motor  17 , battery holder  16  and epicyclic geartrain  21  are received in a recess  28  in the housing  10  separated from the condiment reservoir  27   a ,  27   b  by the internal wall  29 . 
   The epicyclic geartrain  21  includes four spur gear epicyclic gearsets  111 - 114  mounted coaxially. Each of the gearsets  111 - 114  comprises planet gears P 1 , P 2 , P 3 , P 4  meshed with a respective sun gear S 1 , S 2 , S 3 , S 4  and supported upon a planet carrier C 1 , C 2 , C 3 , C 4 . The planet carriers C 2 , C 3 , C 4  are of common construction, each integrally formed and rotationally fast with a respective one of the sun gears S 1 , S 2 , S 3 . The carrier C 1 , C 2 , C 3 , C 4  includes three integral parallel, equally angularly spaced shaft portions for supporting the three planet gears P 1 , P 2 , P 3 , P 4 . The gearsets  111 - 114  are stacked within a non-rotating ring gear R, with which all the planet gears P 1 , P 2 , P 3 , P 4  mesh. At the output of the geartrain  21   a  coupler  50  transmits torque from the carrier C 1  to the shaft  22 , while at the input to the geartrain the motor shaft  46  is rotationally fast with the sun gear S 4 . 
   First and second rotary grinding mechanisms  56   a ,  56   b  are of like construction, each having respective first and second stators  30   a ,  30   b  received in the opposing lateral openings  41   a ,  41   b  in the housing  10 . The shafts  25   a ,  25   b  are rotationally fast with their respective grinding rotors  26   a ,  26   b  which cooperate with, and are generally received within, respective grinding stators  30   a ,  30   b  for grinding condiment therebetween. The drive shafts  25   a ,  25   b  extend through the respective reservoirs  27   a ,  27   b  and are coaxial with the first transverse axis  48 . The shafts  25   a ,  25   b  have a square cross section with threaded tips  32   a ;  32   b  engaged in the threaded adjuster nuts  31 , their square section outer ends received in complementary recesses  52  in respective ones of the rotors  26   a ,  26   b , while their inner ends are received in congruent apertures  54  in couplers  53  for rotation thereof. Each grinding mechanism  56   a ,  56   b  is of a unidirectional type, which has helical teeth (not shown) and thus operates best in one direction. An adjuster nut  31  received on a threaded tip  32  of the shafts  25   a ,  25   b  engages and moves the rotors  26   a ,  26   b  axially for adjusting the size of the annular discharge opening  33  between the rotor  26   a  and stator  30   a , and hence the fineness of the ground condiment. 
   The components of the grinding mechanisms, including the rotors  26   a ,  26   b , stators  30   a ,  30   b  and adjuster nuts  31  are completely recessed within the housing  10 . Ground condiment from the discharge openings  33  passes out through the respective recesses  34   a ,  34   b  in use. The recesses  34   a ,  34   b  extend about the lateral openings  41   a ,  41   b  and each have annular peripheral walls  37  and a rim  35  lying in planes  36  parallel to the upright axis  15 . The lateral openings  41   a ,  41   b  extends centrally through the recesses  34   a ,  34   b . The lower section of the walls  59  is upwardly concave to catch any condiment particles dislodged from or through the grinding mechanisms when the grinder is generally upright. 
   A first one-way clutch  55  provides for one-directional transmission of torque between the first grinding mechanism  56   a  and a first bevel gear  57 , while the second one-way clutch  58  correspondingly provides for one-directional transmission of torque between the second grinding mechanism  56   b  and a second bevel gear  60 . Both one-way clutches  55 ,  58  are of the ratchet type and of like construction, each including a first and second member between which torque transmission is connected and disconnected. The first member is integral with the bevel gears  57 ,  60  and comprises circumferentially spaced teeth  61  formed on one side axial of the bevel gears  57 ,  60 . The second member is a pawl  62  urged by a compression spring  63  into engagement with the teeth  61  to provide unidirectional torque transmission. Each coupler  53  includes a recess  64  in which the spring  63  and pawl  62  are received, and a cylindrical stem  65  for rotatably supporting the bevel gears  57 ,  60  in a journal block  66 . The recess  64  has a square cross section and the pawl  62  has a complementary square cross section; such that the pawl  62  is rotationally fast with the coupler  53  but can move axially in the recess  64 . Rings  67  retain the one-way clutches  55 ,  58  within the journal block  66 . 
   The third bevel gear  23  is mounted in mesh with the first and second bevel gears  57 ,  60  in the journal block  66 . The bevel gear  23  is driven by the motor  17 , through the geartrain  21  and shaft  22 . So that the motor  17  is selectively operated (in forward or reverse) depending upon which of the recesses  34   a ,  34   b  are generally opening downward, the DPDT tilt switch  70  is configured for detecting a change in orientation on a second transverse axis  71  substantially orthogonal to the first transverse axis  48  and includes a pendulum  73  mounted to swing about the second transverse axis  71 . 
     FIG. 6  illustrates the circuit for supplying current from the batteries  140  to the motor  17  (shown in an operating state). A bipolar junction transistor  72  is connected in the circuit for switching the current to the motor  17 , the emitter E and base B of the transistor  72  being connected between the battery  140  and the DPDT tilt switch  70 . The ball-type tilt switch  20  is connected between the base B and collector C of transistor  72 . In this configuration the pendulum-type DPDT tilt switch  70  has a centre-off position (not shown) and is operated when the grinder is inclined about the axis  71  (see  FIG. 5 ) to either side of its upright position by a first angle (for instance, 25-35°) thereby creating a voltage across the ball-type tilt switch  20 . As this first angle is increased (for instance, to 40-50°) the ball-type tilt switch  20  is operated to switch the transistor on and thus supply current to the motor. 
   In use, pepper may be placed in reservoir  27   a , and salt crystals in reservoir  27   b . Grasping the waist portion  11  and tilting the grinder about 40°-50° from its upright position about the axis  71  to incline the recess  34   a  downwardly causes the motor  17  to be actuated by operation of the tilt switches  70 ,  20  and torque is transmitted through the one-way clutch  55  to the grinding mechanism  56   a , to grind and dispense pepper from the reservoir  27   a . As no torque is transmitted by the one-way clutch  58 , the grinding mechanism  56   b  is stationary. The tilt switches  70 ,  20  open when the grinder is supported upright when not in use and correspondingly, when tilting the grinder in the opposite direction through about 40°-50° from its upright position about the axis  71  torque is transmitted through the one-way clutch  58  to the grinding mechanism  56   b  to grind and dispense salt from the reservoir  27   b  and no torque is transmitted by the one-way clutch  55  to grinding mechanism  56   a  which is stationary. 
   Aspects of the present invention have been described by way of example only and it should be appreciated that modifications and additions may be made thereto without departing from the scope thereof.