Abstract:
A pill crusher has a paper cup receptacle having an upwardly open, frusto-conical recess for receiving a paper cup, a plunger having a frusto-conical shape complimentary to that of the recess, the plunger being above and coaxial with the recess, an electric motor and a reciprocating drive transmission between the electric motor and the plunger for displacing the plunger into and out of the recess. The reciprocatory drive transmission comprises a worm and nut drive transmission for rotating the plunger while displacing the plunger into the receptacle. A drive control connected to the electric motor controls the motor so as to displace the plunger into and out of the recess.

Description:
FIELD OF THE INVENTION 
   The present invention relates to pill crushers and, more particularly, to electrically operated pill crushers. 
   The present application claims priority from Canadian Patent Application Serial Number 2,447,753, filed Nov. 3, 2003, entitled “Pill Crushers”. 
   BACKGROUND OF THE INVENTION 
   Some patients for whom medication is provided in the form of pills, because of their poor medical conditions, have difficulty in swallowing the pills. It has therefore previously been proposed to provide a pill crusher, by means of which pills can be crushed into a powder form. The powder produced in this way can then be added to a liquid to provide a mixture which is more easily consumable by such patients. 
   In most healthcare facilities, crushing pills for patients is a frequently performed task. At the present time, pills are usually crushed by employing a manual pill crusher, but this frequently results in the manual exertion of high forces, or postures and repetitive movements that can contribute to injuries of the hands, wrists and shoulders. Furthermore, inhalation of airborne dust, which occurs during the crushing process, has also been reported to be a problem. 
   To reduce the magnitude of the forces required to crush pills, manufacturers of manual pill crushers have designed lever-type mechanical devices employing a metal head attached to a lever arm which pivots about a fulcrum. 
   However, even with the use of such lever-type mechanical devices, the forces required are often still high, and the users are still required to assume awkward postures and to perform repetitive movements. Awkward postures of the shoulder occur because pill crushers are typically placed on the tops of medication carts and the heights of the top surfaces of the medication carts are usually too high for most workers. The design of a typical lever-type crusher is such that downward forces are required to be exerted on a straight handle, which results in awkward postures of the wrist. 
   Examples of prior manually actuated pill crushers are disclosed, for example, in U.S. Pat. Nos. 2,631,786; 3,915,393; 6,059,209 and 6,357,679. 
   In U.S. Pat. No. 6,508,424 there is disclosed a battery operated pill crusher comprising a cylindrical plunger which can be moved downwardly into a cylindrical container, the bottom of which is in the form of a turntable which can be rotated by an electric motor and which has an upper surface formed with a plurality of grinding protrusions. In use of this prior device, a pill is inserted between the upper surface of the turntable and the plunger, the plunger is pressed downwardly and the turntable is then rotated, so that rotational motion as well as compression is applied to the pill, which is thereby pulverized. However, this prior device has the disadvantage that it is necessary to press the plunger down manually toward the turntable, which is resiliently mounted, so that the crushing forces which can be exerted on the pill are limited. Another disadvantage of this prior device is the risk that rotation of the turntable could be initiated by pressing directly onto the turntable with, for example, a finger, while the plunger is removed. 
   Canadian Patent Number 2,057,245 discloses a pill crusher and grinder for use especially in nursing homes and domestic environments, the pill crusher and grinder having a pill or tablet-receiving and holding means, a rotary crushing and grinding means having a rotary shaft, a tablet contacting element on one end of the shaft and rotatable therewith and means for rotating the shaft. In a preferred embodiment, the shaft is adapted firstly to break the tablet into small pieces and then to crush and grind it by rotary action within the pill receiving and holding means. The means for rotating the shaft is a manually operable handle. The rotary shaft is screw-threaded and is received in a complementary screw-threaded receiver, which is fixed with respect to the tablet receiving and holding means. However, this prior device has the disadvantage that it employs rotary blades, which can pose a safety hazard. 
   In U.S. Pat. No. 5,067,666 there is disclosed a battery operated pill crusher comprising a selectively activatable motor to produce a power source to a cam-driven ram which reciprocates once on a vertical axis into and out of engagement with a pill in a medication cup with sufficient force to “smash” the pill. The ram is returned to its uppermost position by the coaction of the eccentric cam and a compression spring operatively circumscribed thereabout. However, this prior device has the disadvantage that the ram does not rotate while being displaced, so that the crushing abilities which can be exerted on the pill are limited. Another disadvantage of this prior device is the use of a compression spring to retract the plunger, which may weaken its ability to retract the plunger over time. 
   SUMMARY OF THE INVENTION 
   According to the present invention, there is provided a pill crusher which comprises a paper cup receptacle having an upwardly open, frusto-conical recess for receiving a paper cup, a plunger having a frusto-conical shape complimentary to that of the recess, the plunger being above and coaxial with the recess, an electric motor and a reciprocatory drive transmission between the electric motor and the plunger. 
   In a preferred embodiment of the present invention, the reciprocatory drive transmission comprises a worm and nut drive transmission, and a drive control is connected to the electric motor which comprises means for energizing the motor so as to displace the plunger into and out of the recess. 
   When the pill crusher according to the present invention is in operation, a paper cup is inserted into the receptacle, at least one pill is inserted into the paper cup and preferably, a second paper cup is inserted into the first paper cup, so that the pill or pills is/are located between the two paper cups in order to prevent cross-contamination. The electric motor is then energized under the control of the drive control so as to displace the plunger into the second paper cup and the recess in the receptacle until reaching a first predetermined distance or a predetermined pressure, which is sufficient to ensure that the pill is broken into segments or crushed. During this stroke, the plunger is rotated by the worm and nut drive, so that the pill is subjected to both rotational forces and compression forces, and the pill is broken into segments or crushed, the plunger terminating its downward movement at a distance from the bottom of the recess or at the predetermined pressure. The plunger is subsequently displaced from the pill, under the control of the drive control, and may be again displaced toward the pill through a second predetermined stroke to break the pill or pills into smaller segments. During this second predetermined stroke, the plunger is again rotated by the worm and nut drive transmission. The plunger is subsequently again displaced from the pill segments, under the control of the drive control, and may be again displaced toward the pill through a third predetermined stroke to ensure that each pill is pulverized by crushing and grinding into a fine powder. During this third stroke, the plunger is again rotated by the worm and drive transmission. 
   Preferably an undersurface of the plunger and a bottom surface of the recess are both dimpled in order to promote effective crushing and pulverization of the pill. 

   
     DESCRIPTION OF THE DRAWINGS 
     The present invention will be more readily understood from the following description of a preferred embodiment thereof given, by way of example, with reference to the accompanying drawings (Note that the ‘A’ drawings, e.g.,  FIG. 2A , refer to the first embodiment and the ‘B’ drawings, e.g.,  FIG. 2B , refer to the second embodiment), in which:— 
       FIG. 1A  shows a view in perspective of a pill crusher embodying the first embodiment of the present invention; 
       FIG. 1B  shows a view in perspective of a pill crusher embodying the second embodiment of the present invention; 
       FIG. 2A  shows a view in perspective of the pill crusher of  FIG. 1A  with a housing removed to show components in the interior of the pill crusher of  FIG. 1A ; 
       FIG. 2B  shows a view in perspective of the pill crusher of  FIG. 1B  with a housing removed to show components in the interior of the pill crusher of  FIG. 1B ; 
       FIG. 3A  shows a view taken in vertical cross-section through parts of the pill crusher of  FIGS. 1A and 2A ; 
       FIG. 3B  shows a view taken in vertical cross-section through parts of the pill crusher of  FIGS. 1B and 2B ; 
     FIG.  3 A(i) shows a view of gears taken in section along the line  3 A(i)- 3 A(i) of  FIG. 3A ; 
       FIG. 4A  shows a broken-away view, corresponding to parts of  FIG. 3A , but with a plunger displaced downwardly from the position in which it is shown in  FIG. 3A ; 
       FIG. 4B  shows a broken-away view, corresponding to parts of  FIG. 3B , but with a plunger displaced downwardly from the position in which it is shown in  FIG. 3B ; 
     FIGS.  5 A(i) and  5 A(ii) show broken-away views in vertical cross-section of parts of the pill crusher of  FIG. 1A ; 
     FIGS.  5 B(i) and  5 B(ii) show broken-away views in vertical cross-section of parts of the pill crusher of  FIG. 1B ; 
       FIG. 6A  shows a broken-away view in perspective of parts of the pill crusher of  FIG. 1A ; 
       FIG. 6B  shows a broken-away view in perspective of parts of the pill crusher of  FIG. 1B ; 
       FIGS. 7A and 8A  show broken-away views in horizontal cross-section through parts of the pill crusher shown in  FIG. 1A ; 
       FIGS. 7B and 8B  show broken-away views in horizontal cross-section through parts of the pill crusher shown in  FIG. 1B ; 
     FIGS.  9 A(i) and  9 A(ii) show circuit diagrams of a control unit in the pill crusher of  FIG. 1A ; 
     FIGS.  9 B(i),  9 B(ii) and  9 B(iii) show circuit diagrams of a control unit in the pill crusher of  FIG. 11B ; 
       FIG. 10A  shows a flowchart of a routine followed by the circuit of FIGS.  9 A(i) and  9 A(ii) when the circuit is powered up; 
       FIG. 10B  shows a flowchart of a routine followed by the circuit of FIGS.  9 B(i),  9 B(ii), and  9 B(iii) when the circuit is powered up; 
       FIG. 11A  shows a flowchart of a routine followed by the circuit prior to operation of the pill crusher of  FIG. 1A ; 
       FIG. 11B  shows a flowchart of a routine followed by the circuit prior to operation of the pill crusher of  FIG. 1B ; 
       FIG. 12A  shows a flowchart of a routine followed by the circuit during operation of the pill crusher of  FIG. 1A ; 
       FIG. 12B  shows a flowchart of a routine followed by the circuit during operation of the pill crusher of  FIG. 1B ; 
     FIGS.  12 A(i)-(iv) show flowcharts of subroutines followed by the circuit during the operation illustrated in  FIG. 12A ; and 
     FIGS.  12 B(i)-(iv) show flowcharts of subroutines followed by the circuit during the operation illustrated in  FIG. 12B . 
   

   DETAILED DESCRIPTION OF THE INVENTION 
   In  FIGS. 1A and 1B , first and second embodiments, respectively, are shown of a pill crusher according to the invention, which is indicated generally by reference  10  and which has a housing  12 . In  FIG. 1A  of the first embodiment there is shown a cylindrically-curved paper cup holder  14  at a rear corner of the housing  12 . In  FIG. 1B  of the second embodiment there is shown a drop handle  11  on the side of the housing  12 . There is also a second drop handle (not shown) located on the opposite side of the housing  12 . 
   Referring now to  FIGS. 2A and 2B , which show pill crusher  10  with housing  12  removed, it can be seen that the pill crusher has a pair of parallel vertical side walls  16 , between which extends a platform  18 . 
   In  FIG. 2A  of the first embodiment platform  18  projects forwardly from the side walls  16  and is supported on a pair of posts  20  and  21  at opposite front corners of the pill crusher. At the rear of the pill crusher, there is provided a low noise electric motor  22  (as seen in  FIG. 3A ) having a vertical axis. 
   In  FIG. 2B  of the second embodiment there is provided a low noise electric motor  22  (as seen in  FIG. 3B ) having a vertical axis, at the front of the pill crusher. 
   As shown in FIGS.  3 A and  3 A(i) of the first embodiment, the electric motor  22  has a drive shaft  24 , which carries a gear  26  meshing with a gear  28  mounted on a vertical shaft  30 , which is journaled at its lower end in a base plate  32  and, at its upper end, in a platform  34  on which the motor  22  is mounted. A further gear  36  on the shaft  30  meshes with a gear  38  on a shaft  40 , which is also journaled at opposite ends in the base plate  32  and platform  52 . A gear  42  on the shaft  40  meshes, in turn, with a gear  44  mounted on the lower end of a vertical shaft  46 . The shaft  46  is journaled at opposite ends in bearings  48  and  50 . The bearings  48  are mounted in the platform  34  and  52  at the lower end of the shaft  46 , and the bearings  50  are mounted in a pair of vertically spaced platforms  54 , which extend between the side walls  16 . 
   The upper end of the vertical shaft  46  is connected by a chain and sprocket drive, indicated generally by reference numeral  56 , to a square-sectioned upper end portion  55  of a shaft  57  at the upper end of a worm gear  58 , which has a vertical axis parallel to that of the shaft  46 . 
   The worm gear  58  meshes with a threaded nut  60 , which is fixed to the platform  18 , and at its lower end carries a plunger which is indicated generally by reference numeral  62  and which is made of nylon or other suitable plastic material. 
   As shown in  FIG. 3B  of the second embodiment, the electric motor  22  has a drive input  24 . Inserted into drive input  24  is a drive shaft  25 , which carries a gear  26 , which is journaled at opposite ends in bearings  48 , which are mounted at its lower end in a base plate  32  on which the motor  22  is mounted and, at its upper end, in a platform  34 . The gear  26  is connected by a grooved belt pulley drive  56  (as seen in  FIG. 2B ), to a second gear  36 , which is journaled at opposite ends in bearings  50 , which are mounted at its lower end in a base plate  33  and, at its upper end, in a platform  35 . The gear  36  is carried on shaft  57  at the upper end of a worm gear  58 , which has a vertical axis parallel to that of shaft  25 . 
   The worm gear  58  meshes with a threaded nut  60 , which is fixed to the platform  18 , and at its lower end carries a plunger  62  which is made of stainless steel or other suitable metal material. 
   As shown in  FIGS. 3A and 3B , the plunger  62  co-operates with a receptacle indicated generally by reference numeral  64 , which is pivotally mounted on the post  20  as described in greater detail below. 
   The receptacle  64  has an upwardly-open, frusto-conical recess  66  (as seen in  FIGS. 2A and 2B ), in which a pair of paper cups  68  and  69 , are inserted one into the other (as seen in  FIGS. 4A and 4B ); a body portion  70 , which forms the wall of the recess  66 ; and a circular plate  72 , which is secured by screws (not shown) in the underside of the body portion  70  and which forms the bottom of the recess  66 . 
   The plunger  62  has a frusto-conical surface  73 , which is complementary in shape to the frusto-conical recess  66 , and an undersurface  74 . The undersurface  74  of the plunger  62  and the opposed upper surface  75  of the plate  72  forming the bottom of the recess  66  are both dimpled. 
   Referring now to  FIG. 6A  of the first embodiment, the body  70  of the receptacle  64  has an upstanding front wall  78 , an upstanding sidewall  80 , which is spaced from the wall  78  by a gap  82 , and a cylindrically curved wall  84  connecting inner surfaces of the walls  78  and  80 . 
   A lower end  88  of the post  20  is formed with flat opposite sides  86  so as to enable the lower end  88  to slide through the gap  82  into and out of a cylindrical space within the curved wall  84 . Normally, the lower end  88  of the post  20  is located within this cylindrical space, so that the cylindrical wall  84  and the lower end  88  of the post  20  form a readily releasable pivotal connection between the receptacle  64  and the pill crusher  10 . 
   By pivoting the receptacle  64  about the post  20  into the relative positions in which they are shown in  FIG. 6A  of the first embodiment, the receptacle  64  can be released from the post  20  and, thus, from the pill crusher  10  to enable the receptacle  64  to be thoroughly cleaned. 
   Referring now to  FIG. 6B  of the second embodiment, the body  70  of the receptacle  64  has an upstanding front wall  78 , with a cylindrically curved end  84 . An opening located on the undersurface of the upstanding front wall  78  at the cylindrically curved end  84  slides onto post  20  to form a readily releasable pivotal connection between the receptacle  64  and the pill crusher  10 . 
   By pivoting the receptacle  64  about the post  20  into the relative positions in which they are shown in  FIG. 6B  of the second embodiment, the receptacle  64  can be released from the post  20  and, thus, from the pill crusher  10  to enable the receptacle  64  to be thoroughly cleaned. 
   In  FIGS. 1A and 1B , the receptacle  64  is shown in its closed position, in which the body  70  of the receptacle  64 , with the recess  66 , is located within and concealed within the housing  12 . By pivotation about the post  20 , the receptacle  64  can be displaced into an opened position, in which it is shown in  FIGS. 2A and 2B  and in which the recess  66  is accessible at the exterior of the housing  12 . 
   The walls  78  (and  80  in the first embodiment) close the opening in the housing  12  when the receptacle  64  is in its closed position during the crushing of the pill, and therefore airborne dust levels are reduced during the crushing operation and, also, the operator of the pill crusher  10  is prevented from inserting his or her fingers inside the housing  12 . 
   While the pill crusher is in use, it can, for convenience, be mounted on the working surface of a medication cart, which is pushed from room to room by a nurse and used for preparing medications for administration to patients. For that purpose, the pill  91  is placed between the two paper cups  68  and  69 , as seen in  FIGS. 4A and 4B , in order to minimize contamination of the plunger  62 . The pill is then pulverized, as described below, and the top cup  69  is then removed from the bottom cup  68  to allow the powder produced by the pulverization to be mixed with juice or food for consumption by the patient. 
   To initiate the grinding operation in the first embodiment, the operator is required to simultaneously press buttons  90  which are located at opposite sides of the housing  12 . The operator is therefore required to use both hands to press these buttons  90 , so that the operator&#39;s hands must be located away from the vicinity in which the crushing operation occurs. As a further safety measure, the electric motor  22  cannot be energized unless the receptacle  64  is in its closed position, in which the recess  66  is located below the plunger  62  and the opening in the housing  12 , through which the receptacle  64  pivots between its closed and opened positions, is closed by the walls  78  and  80  of the receptacle  64 , thereby preventing access to the interior of the housing  12  and, in particular, at the region of the plunger  62 . 
   To initiate the grinding operation in the second embodiment, the operator is required to press button  90  which is located at the top of the front of the housing  12 . As a safety measure, the electric motor  22  cannot be energized unless the receptacle  64  is in its closed position, in which the recess  66  is located below the plunger  62 ; and the opening in the housing  12 , through which the receptacle  64  pivots between its closed and opened positions, is closed by the wall  78  of the receptacle  64 , thereby preventing access to the interior of the housing  12  and, in particular, at the region of the plunger  62 . 
   In the first embodiment, to ensure effective pulverization with the pill  91  located between the paper cups  68  and  69 , the plunger  62  is first moved downwardly to initiate the crushing of the pill  91  as seen in  FIG. 4A . The plunger  62  is then raised by a small distance, as seen in FIG.  5 A(i), in which this distance has been exaggerated to facilitate the illustration of the operation, after which the plunger  62  is then twice lowered again, as seen in FIG.  5 A(ii), and raised again, to pulverize the pill  91 . As the plunger  62  is lowered, it is simultaneously rotated. Finally, the plunger is raised into a “Park” position, in which it is shown in  FIG. 3A , to enable the paper cups  68  and  69  to be withdrawn from the pill crusher  10 . 
   In the second embodiment, to ensure effective pulverization of the pill  91  located between the paper cups  68  and  69 , the plunger  62  is moved downwardly to initiate the crushing of the pill  91  as seen in  FIG. 4B . As the plunger  62  is lowered, it is simultaneously rotated. The plunger is raised into a “Park” position, in which it is shown in  FIG. 3B , to enable the paper cups  68  and  69  to be withdrawn from the pill crusher  10 . 
   The grinding of the pill is promoted by the rotation of the plunger  62  and by the dimpling of the opposed surfaces of the bottom of the receptacle  64  and the underside of the plunger  62 . 
   The operation of the first embodiment of the pill crusher  10  is controlled by a control circuit shown in FIGS.  9 A(i) and  9 A(ii), which includes a microprocessor  100  which is a PIC 16 F 870 microprocessor sold by Microchip Corporation, a voltage regulator  101  and a LCD  102  provided with a negative voltage generator  104 . Through gates G 1 , G 2  and G 3 , and through an H-circuit comprising transistors T 1 -T 6 , the microprocessor  100  controls operation of the motor  22 , as described below. 
   When this circuit is energized by connection to its battery, the microprocessor  100  performs the routine shown in  FIG. 10A  of the first embodiment by setting up its internal functions and then initializing the LCD  102 , which then displays the word “INITIALIZING”. 
   LEDs T 9  and T 10  are then energized. The LEDs T 9  and T 10  are provided on a post  92  (as seen in  FIG. 2A ) and co-operate with a pair of photodiodes D 2  and D 3  for sensing the vertical position of the top of the shaft, the photodiodes D 2  and D 3  being provided on a post  93  parallel to the post  92 . 
   If the plunger  62  is not in its fully raised or “rest” position, the motor  22  is energized to raise the plunger  62  into this position. 
   After a one-second delay, a bicolour LED D 1 , which is visible at the front of the housing  12 , is changed to green, and the LCD  102  displays the word “READY”. 
   The microprocessor  100  then cycles through the loop shown in  FIG. 11A  until the pill crusher is operated. 
   When the pill  91  is inserted with the paper cups  68  and  69  into the receptacle  64 , the receptacle  64  must be moved into its closed position, in which it closes a magnetically operated switch S 3 , to prevent access to the interior of the housing  12  and to counteract the escape of dust from the housing during the crushing of the pill  91 . 
   The operator then presses the two buttons  90  on opposite sides of the housing  12  to close switches S 1  and S 2 , which are connected in series with the switch S 3 . 
   The closure of the three switches S 1 -S 3  initiates the routine shown in  FIG. 12A  of the first embodiment by changing the LED D 1  to red and performing a battery health routine, illustrated in FIG.  12 A(iv), to ensure that the voltage of the battery remains sufficiently high. 
   The LED  102  is then changed to display the word “CRUSHING” and the vertical position of the plunger  62  is then checked as described above. 
   If the plunger  62  is not in its fully raised position, the LED D 1  is changed to yellow, the motor  22  is started with a soft start as shown by the subroutine of FIG.  12 A(ii) and the plunger  62  is raised to the fully raised position, the subroutine of FIG.  12 A(i) being employed to brake the motor  22 . The LED D 1  is then changed back to green. 
   With the plunger  62  located in its fully raised position, the motor  22  is energized by a soft start as illustrated in the subroutine of FIG.  12 A(iii), to move the plunger downward, as described above, to initiate the crushing of the pill. 
   When the photodiode D 3  senses that the plunger  62  has reached its lower position, the subroutine of FIG.  12 A(ii) is again initiated, after a one-second delay, to raise the plunger  62 . 
   As shown in  FIG. 12A , the plunger  62  is then lowered and raised again twice, so that the pill  91  is pulverized by three downward strokes of the plunger  62 . 
   However, it has been found that in some cases, two downward strokes of the plunger  62  are sufficient, and the programming of the microprocessor  100  can be readily modified to omit one of the three strokes. 
   When the crushing of the pill has been completed, the LCD  102  is changed to display the word “READY” again, and the LED D 1  is again changed to green. 
   The operation of the second embodiment of the pill crusher  10  is controlled by a control circuit shown in FIGS.  9 B(i),  9 B(ii), and  9 B(iii), which includes a microprocessor  100  which is a PIC 18 F 458 microprocessor sold by Microchip Corporation, a voltage regulator  101  and a LCD  102 . Through the motor control board (as seen in FIG.  9 B(ii)), which consists of a H-Bridge controller, power MOSFETs, and related discrete components, the microprocessor  100  controls operation of the motor  22 , as described below. 
   When this circuit is energized by connection to its battery, the microprocessor  100  performs the routine shown in  FIG. 10B  by setting up its internal functions and then initializing the LCD  102 , which then displays the word “INITIALIZING”. 
   The photo-reflective infrared sensor  63  is then energized which allows the detection of the position of the plunger. If the plunger  62  is not in its fully raised or “rest” position, the motor  22  is energized to raise the plunger  62  into this position. 
   After a one-second delay, a bicolour LED D 1 , which is visible at the front of the housing  12 , is changed to green, and the LCD  102  displays the word “READY” as shown by the subroutine in FIG.  12 B(iv), and also displays the battery power with the words “BATTERY: xx %” as shown by the subroutine in FIG.  12 B(iii), where ‘xx %’ equals ‘100%’, ‘75%’, ‘50%’, or ‘25%’. 
   The microprocessor  100  then cycles through the loop shown in  FIG. 11B  until the pill crusher is operated. 
   When the pill  91  is inserted with the paper cups  68  and  69  into the receptacle  64 , the receptacle  64  must be moved into its closed position, in which it closes a magnetically operated switch S 2 , to prevent access to the interior of the housing  12  and to counteract the escape of dust from the housing during the crushing of the pill  91 . 
   The operator then presses the button  90  on the top of the front of the housing  12  to close switch S 1 . 
   The closure of the switch S 1  initiates the routine shown in  FIG. 12B  by changing the LED D 1  to red. The LED  102  is then changed to display the words “CRUSHING; PLEASE WAIT” and the receptacle  64  is verified to be in the closed position, and if so, the door lock solenoid  65  is energized to lock the receptacle  64  into position and prevent opening. If the receptacle  64  has been moved to the open position, the crushing sequence is halted, and the LCD  102  is changed to display “DOOR OPEN”. Only when the receptacle  64  is in the closed position will the crushing sequence be allowed to begin again. 
   Upon the success of the above operations, the vertical position of the plunger  62  is then checked as described above. If the plunger  62  is not in the raised position, a homing sequence is initiated to bring the plunger  62  into position. 
   With the plunger  62  located in its fully raised position, the motor  22  is energized by a plunger down routine as illustrated in the subroutine of FIG.  12 B(ii), to move the plunger downward, as described above, to initiate the crushing of the pill. 
   When the pressure sensor D 4  (as seen in  FIG. 4B ) senses that the plunger  62  has reached the first predetermined pressure, the motor  22  is energized by a plunger up routine as illustrated in the subroutine of FIG.  12 B(i), after a one-second delay, to raise the plunger  62 . 
   When the crushing of the pill has been completed, the LCD  102  is changed to display the word “COMPLETE”, and the LED D 1  is again changed to green. 
   Although the particular preferred embodiments of the invention have been disclosed in detail for illustrative purposes, it will be recognized that variations or modifications of the disclosed apparatus lie within the scope of the present invention.