# US 4,396,990 A · Checking system for checking the functional integrity of the operating magnets in a flatbed knitting machine > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 4,396,990 A - Document ID: US4396990A - Status: Granted - Kind: A - Application number: 06/190,770 - Filed: 1980-09-25 - Granted: 1983-08-02 - Earliest claimed: 1979-10-01 - Assignees: Universal Maschinenfabrik Dr. Rudolf Schieber GmbH & Co. KG - Inventors: Albin K. Weingartner; David A. Retallick - Web page: https://patentgrep.com/patent/US4396990A ## CPC - G01R 31/00: Arrangements for testing electric properties; Arrangements for locating electric faults; Arrangements for electrical testing characterised by what is being tested not provided for elsewhere ({measuring superconductive properties G01R33/1238;} testing line transmission systems H04B3/46; testing or measuring semiconductors or solid state devices during manufacture {H10P74/00}) - D04B 35/10: Indicating, warning, or safety devices, e.g. stop motions - G01R 31/3278: {of relays, solenoids or reed switches (measuring contact resistance G01R27/205; high voltage magnetic switches G01R31/3271, G01R31/333; testing electric windings G01R31/72; monitoring of fail safe circuits H01H47/002)} - G01R: MEASURING ELECTRIC VARIABLES; MEASURING MAGNETIC VARIABLES (indicating correct tuning of resonant circuits H03J3/12) - D04B: KNITTING ## Abstract A system for checking the functional state of the operating magnets in a tbed knitting machine includes a microprocessor, a keyboard, a display unit, and sensors detecting short-circuit and open-circuit conditions in the magnets and their connections. In order to avoid dismantling the machine to check the magnets, the magnets are subjected in turn to pulse sequences at respective different frequencies and their behavior is monitored. One can monitor the vibrational noise of the magnets or the rise time of current and voltage in the magnets. The checking process can be initiated automatically, for example each time the machine is started up, or controlled manually via the keyboard. Frequencies within the range of 1 to 50 Hz are preferably used. ## Claims ### Claim 1 An electromagnetically controlled flatbed knitting machine comprising a checking system for checking the operating state of operating magnets in said machine, said system comprising: amplifier means for feeding pulse sequences to said operating magnets in response to respective control signals; control means, including at least a microprocessor and a keyboard connected thereto, for selectively providing said control signals to said amplifier means, said control signals having different frequencies according to different functions of said operating magnets; sensing means having outputs monitored by said microprocessor for sensing whether or not each operating magnet operates properly in response to said control signals; and display means controlled by said microprocessor in accordance with the monitored sensing means outputs for indicating whether or not each operating magnet is operating properly. ### Claim 2 (depends on 1) A knitting machine according to claim 1, wherein said amplifier means energizes and de-energizes said magents at respective different frequencies within the range of 1 to 50 Hz. ### Claim 3 (depends on 1) A knitting machine according to claim 1, wherein said sensing means includes sensors connected to the microprocessor for detecting noise which occurs upon energization and de-energization of said magnets. ### Claim 4 (depends on 1) A knitting machine according to claim 1, wherein said microprocessor monitors the rise time of current and voltage in said magnets. ### Claim 5 (depends on 1) A knitting machine according to claim 1, wherein said control means includes a cyclic pulse generator connected to the microprocessor for providing said pulse sequences to the individual magnets each on the basis of a signal supplied by said keyboard. ### Claim 6 (depends on 1) A knitting machine according to claim 1, in which said control means automatically feeds said pulse sequences to the magnets in response to a signal supplied to the microprocessor. ### Claim 7 (depends on 6) A knitting machine according to claim 6, in which the signal supplied to said microprocessor is supplied by the keyboard and/or automatically upon starting up of the machine and/or intermittently during operation of the machine. ### Claim 8 (depends on 1) A knitting machine according to claim 1, in which said control means generates a signal to stop the machine in the event of a defeat being detected in one or more of the magnets. ### Claim 9 (depends on 1) A knitting machine according to claim 1, in which the microprocessor controls said display means to display the functional state of the magnets and also an identification of the respective magnets. ### Claim 10 (depends on 1) A knitting machine according to claim 1, which includes a separate amplifier provided for each magnet. ### Claim 11 (depends on 1) A knitting machine according to claim 1, in which the amplifier means includes sensor means for detecting short-circuit and open-circuit conditions.