# US 9,750,875 B2 · Infusion pumps > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 9,750,875 B2 - Document ID: US9750875B2 - Status: Granted - Kind: B2 - Application number: 12/890,320 - Filed: 2010-09-24 - Published: 2012-03-29 - Granted: 2017-09-05 - Earliest claimed: 2010-09-24 - Assignees: perQflo, LLC - Applicants: Roger E. Smith; James Causey; Scott M. Loftin - Inventors: Roger E. Smith; James Causey; Scott M. Loftin - Web page: https://patentgrep.com/patent/US9750875B2 ## CPC - A61M 5/1452: {pressurised by means of pistons} - A61M 5/14216: {Reciprocating piston type} - A61M 5/14546: {Front-loading type injectors} - A61M 5/16804: {Active flow controllers} - A61M 5/16854: {by monitoring line pressure} - A61M 5/16877: {Passive flow controllers; Devices for setting a flow rate (clamp-type valves A61M39/28)} - A61M 5/16863: {Occlusion detection} - A61M 2205/073: Syringe, piston type - A61M 2205/12: with interchangeable cassettes forming partially or totally the fluid circuit - A61M 2205/502: User interfaces, e.g. screens or keyboards - Y10T 29/49826: Assembling or joining - A61M: DEVICES FOR INTRODUCING MEDIA INTO, OR ONTO, THE BODY (introducing media into or onto the bodies of animals A61D7/00; means for inserting tampons A61F13/26; devices for administering food or medicines orally A61J; containers for collecting, storing or administering blood or medical fluids A61J1/05); DEVICES FOR TRANSDUCING BODY MEDIA OR FOR TAKING MEDIA FROM THE BODY (surgery A61B; chemical aspects of surgical articles A61L); DEVICES FOR PRODUCING OR ENDING SLEEP OR STUPOR {(Electrotherapy, e.g. producing anaesthesia by the use of alternating or intermittent currents A61N1/36021)} - Y10T: TECHNICAL SUBJECTS COVERED BY FORMER US CLASSIFICATION ## Abstract Ambulatory infusion pumps, pump assemblies, cartridges, baseplates, cannulas, insertion tools, and related components as well as combinations thereof and related methods. ## Claims ### Claim 1 A method of operating an infusion apparatus including a barrel defining a medicament reservoir, a plunger with at least one seal in the barrel such that there is static and dynamic friction between the barrel and the plunger, a plunger pusher and a motor that drives the plunger pusher by providing motor torque, the method comprising the steps of: when using the motor to propel the plunger pusher to drive the plunger, controlling the motor torque such that the motor torque is continuously within a range having a lower limit torque that is sufficient to overcome a cartridge break force and a running force to move the plunger and an upper limit torque that is low enough so as to not cause leakage past the at least one seal of the plunger due to excessive pressure in the reservoir by exciting the motor at an excitation current such that motor will generate the lower limit torque to propel the pusher, monitoring motor rotation while the motor is being excited, and in response to a lack of rotation of the excited motor, repeating the exciting step at an up-regulated excitation current so as to increase the motor torque from the lower limit torque to an increased motor torque that is below the upper limit. ### Claim 2 (depends on 1) The method as claimed in claim 1, wherein the infusion apparatus includes a constant current source and the motor includes coils, and the step of controlling the motor torque includes limiting the excitation current applied to the motor coils by using the constant current source. ### Claim 3 (depends on 1) The method as claimed in claim 1, wherein the infusion apparatus includes a constant voltage source, and the motor includes coils, and the step of controlling the motor torque includes limiting the excitation current applied to the motor coils by using the constant voltage source. ### Claim 4 (depends on 3) The method as claimed in claim 3, wherein the infusion apparatus includes a programmable linear voltage regulator, and the step of controlling motor torque includes limiting the excitation current with the linear voltage regulator. ### Claim 5 (depends on 3) The method as claimed in claim 3, wherein the infusion apparatus includes a programmable switching voltage regulator, and the step of controlling motor torque includes limiting the excitation current with the switching voltage regulator. ### Claim 6 (depends on 3) The method as claimed in claim 3, wherein the step of limiting the excitation current includes applying pulse width modulating control to the motor coils. ### Claim 7 (depends on 1) The method as claimed in claim 1, wherein the infusion apparatus includes an electronic drive, and the step of controlling motor torque comprises controlling motor torque with the electronic drive. ### Claim 8 (depends on 1) The method as claimed in claim 1, wherein the infusion apparatus includes a battery and the step of controlling motor torque includes pulse width modulating the energy applied from the battery to the motor. ### Claim 9 (depends on 1) The method as claimed in claim 1, wherein the infusion apparatus includes a digital-to-analog converter, and the step of controlling motor torque includes digital-to-analog converter-based voltage control. ### Claim 10 (depends on 1) The method as claimed in claim 1, wherein the infusion apparatus includes a digital potentiometer, and the step of controlling motor torque includes digital potentiometer-based voltage control. ### Claim 11 (depends on 1) The method as claimed in claim 1, wherein the range is between one and twenty mNm. ### Claim 12 (depends on 1) The method as claimed in claim 1, wherein the motor when not being controlled has the capability of providing motor torque exceeding the upper limit by at least 10 or 20 percent. ### Claim 13 (depends on 1) The method as claimed in claim 1, wherein the step of controlling motor torque is conducted during one, some or all of the following pusher procedures: retracting relative to the plunger, homing, zeroing, and running. ### Claim 14 (depends on 1) The method as claimed in claim 1, wherein the step of controlling motor torque comprises controlling motor torque with a pulse width modulation technique. ### Claim 15 (depends on 1) A method as claimed in claim 1, further comprising the step of: controlling the motor to stop from a pusher propelling velocity by decreasing the frequency of a waveform delivered to the motor over time so as to maintain constant positive control of the motor and thereby to precisely control how many turns the motor makes and thus the precise distance the plunger pusher advances before stopping to provide accurate controlled medicament dispensing from the medicament reservoir. ### Claim 16 (depends on 15) A method as claimed in claim 15, wherein decreasing the frequency of a waveform comprises decreasing the frequency of a waveform beginning a predetermined number of motor revolutions prior to stopping.