Pharmaceutical tablet press control mechanism

• US 4,817,006 A
• Filed: 01/07/1988
• Issued: 03/28/1989
• Est. Priority Date: 03/28/1986
• Status: Expired due to Fees

• Current Assignee: Thomas Engine Company, LLC
• Original Assignee: Thomas Engine Company, LLC
• Inventors: Lewis, David A.
• Primary Examiner(s): MANAHAN, TODD E
• Application Number:
  US07/414,158
• Time in Patent Office: 446 Days
• Field of Search: 364/476, 364/473, 364/468, 364/469, 364/134, 425/147, 425/149, 425/170, 425/171, 425/173, 264/40.1, 264/40.5, 264/40.7
• US Class Current: 700/206
• CPC Class Codes: B30B 11/005 Control arrangements
• CPC Class Codes: B30B 15/32 Discharging presses

Abstract

Control and monitoring instrumentation for a high speed double rotary tablet press mechanism is disclosed. Each tablet press side has strain gauges producing signals indicative of table compression. The strain gauges generate control signals received by a peak detector, which holds the maximum strain signal. The peak signals are converted to digital form and provided to a microprocessor that first controls operation of the reject gate and regulates tablet consistency by controlling powder fill into the dies, and second, passes information to RAM. The RAM is shared by a master CPU, clocked 180° out of phase with the microprocessor. The master CPU produces either a CRT or printed output of both raw and statistically abstracted tablet press data.

Claims

1. An apparatus for measuring and displaying information regarding tablets being produced in a rotary tablet press having a mechanism for rejecting defective tablets and having a plurality of tablet dies each with and associated tablet punch set, comprising, in combination:

means for monitoring tablet producing compression at at least one tablet die location and generating successive tablet compression data each time said press rotates, each said tablet compression data indicative of a tablet compression related to a single tablet;

data processing and mechanism control means, connected to said monitoring means, for successfully retrieving each said tablet compression data and processing each said retrieved tablet compression data prior to retrieving the next tablet compression data, said data processing and mechanism control means controlling operation of the defective tablet rejection mechanism according to processed data for a separate tablet, said tablet data processing and mechanism control means operating in accordance with a first master clock signal;

data storage means, connected to said data processing and mechanism control means, for addressably recording at least a portion of the information processed by the data processing and mechanism controlling means, said data processing and mechanism control means accessing said data storage means solely during a first portion of said master clock signal;

central data processing means connected to said data storage means for processing data recorded therein by said data processing and mechanism control means, said central data processing means processing information stored in said data storage means concurrent with the retrieval and processing of tablet compression data by said data processing and mechanism control means, said central data processing means operating in accordance with a second masterclock signal and said central data processing means accessing said data storage means solely during a second portion of said second master clock signal, said second portion of said second master clock signal occurring at a time out of phase with said first portion of said first master clock signal whereby said data processing and mechanism control means and said central data processing means synchronously share said data storage means; and

display means controlled by said central data processing means, for displaying tablet compression information processed from tablet compression data retrieved and processed by said data processing and mechanism control means.

2. Apparatus according to claim 1 and further including rotary angular position means for monitoring the rotational position of the tablet punch sets and generating a position signal for indicating the rotary angular position of the punch sets in time, and wherein said data processing and mechanism control means is responsive to said position signal for initiating retrieval of a said tablet compression data at a specific rotary angular position of the dies.

3. Apparatus according to claim 2 wherein said data processing and mechanism control means is responsive to a rotary angular position of the punch sets for controlling the operation of the defective tablet rejection mechanism for rejecting a defective tablet.

4. Apparatus according to claim 2 wherein said rotary angular position means includes an oscillator responsive to the rotary movement of the dies for generating a first oscillating signal and includes a counter for counting according to said first oscillating signal and generating an output count signal representative of the rotary angular position of the punch sets.

5. Apparatus according to claim 4 wherein said rotary angular position means includes:

a punch proximity detector for sensing the punch sets as they move relative to said detector for generating a second oscillating signal; and

a phase detector means for varying the frequency of said first oscillating signal in accordance with the relative phase relationship of said first oscillating signal and said second oscillating signal.

6. An apparatus according to claim 1 wherein said data processing and mechanism control means analyzes a retrieved tablet compression data of one tablet for deciding whether to reject said one tablet prior to retrieving tablet compression data for the next tablet produced following production of said one tablet.

7. An apparatus according to claim 1 wherein said second master clock signal is 180 degrees out of phase with said first master clock signal.

8. Apparatus according to claim 1 wherein said monitoring means generates an analog signal representative of the compression force during tablet producing compressions and wherein said monitoring means is controllable by said data processing and mechanism control means for selecting approximate peak points of said analog signal as said successive tablet compression data.

9. Apparatus according to claim 8 and further including rotary angular position means for monitoring the rotational position of the tablet punch sets and generating a position signal for indicating the rotary angular position of the punch sets in time, and wherein said data processing and mechanism control means is responsive to said position signal for controlling said monitoring means for selecting the approximate peak points of said analog signal as said successive tablet compression data.

10. Apparatus accordance to claim 9, wherein said rotary angular position means includes a counter for generating said position signal, said position signal formed of digital output counts representative of rotary angular positions of the punch sets, and wherein said data processing and mechanism control means monitors said analog signal for determining the digital output count of said counter at the peak point of said analog signal.

12. An apparatus as claimed in claim 1, wherein the rotary press includes a second mechanism to regulate fill of powder in the dies, and wherein said data processing and mechanism control means also controls operation of the second mechanism.

13. An apparatus as claimed in claim 1, wherein said monitoring means for generating tablet compression data, said data processing and mechanism control means, and said data storage means together comprise a first press control unit, and wherein the apparatus further comprises at least a second press control unit, each said press control unit connected by its data storage means to said central data processing means for processing the tablet compression data, said central data processing means accessing independently each said data storage means of said press control units.

11. Apparatus according to claim 11 wherein said data processing and mechanism control means executes a program and wherein said monitoring means includes interrupt means for interrupting said program in response to said counter reaching a preselected digital output count.

14. An apparatus for measuring and displaying information regarding tablets produced in a rotary tablet press having a mechanism for rejecting defective tablets and having a plurality of tablet dies each with an associated tablet punch set which rotate relative to cams for compression of the punch sets to form the tablets, comprising, in combination:

monitoring means for monitoring the tablet producing compression of each tablet punch set at at least one press location as the punch sets rotate pass the press location, said monitoring means being selectively actuated for generating successive tablet compression data as said press rotates, each said tablet compression data indicative of a tablet compression related to a single tablet;

rotary angular position means for monitoring the rotational position of the tablet punch sets and generating a position signal which changes with the rotation of the punch sets relative to said press location for indicating the rotary angular position of the punch sets;

data processing and mechanism control means, connected to said monitoring means and said rotary angular position means and responsive to said position signal for selectively actuating said monitoring means at predetermined angular positions of the punch sets for successively retrieving tablet compression data, said data processing and mechanism control means processing each said retrieved tablet compression data and controlling operation of the defective tablet rejection mechanism according to processed data for a separate tablet;

data storage means, connected to said data processing and controlling means, for addressably recording at least a portion of the information processed by the data processing and mechanism controlling means; and

display means controlled by said data processing and mechanism control means, for displaying tablet compression information processed from tablet compression data.

15. Apparatus according to claim 14 wherein the mechanism for rejecting defective tablets is selectively actuable and wherein said data processing and mechanism control means is responsive to said position signal for selectively actuating the mechanism for rejecting defective tablets.

16. Apparatus according to claim 14 wherein said rotary angular position means includes an oscillator responsive to the rotary movement of the dies for generating a first oscillating signal.

17. Apparatus according to claim 16, wherein said rotary angular position means includes:

a punch proximity detector for sensing the punch sets as they move relative to said detector for generating a second oscillating signal; and

a phase detector means for varying the frequency of said first oscillating signal in accordance with the relative phase relationship of said first and second oscillating signal.

18. Apparatus accordance to claim 16 wherein said rotary angular position means includes a counter for generating said position signal, said position signal formed of digital output counts representative of rotary angular positions of the punch sets.

19. Apparatus according to claim 14 wherein said rotary angular position means is programmable by said data processing and mechanism control means for generating an interrupt signal when the rotational position of the tablet punch sets occupy a predetermined position, and wherein said data processing and mechanism control means is responsive to said interrupt signal.