# US 11,441,550 B2 · Self-aligning power screw for syringe pump > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 11,441,550 B2 - Document ID: US11441550B2 - Status: Granted - Kind: B2 - Application number: 16/456,080 - Filed: 2019-06-28 - Published: 2020-01-02 - Granted: 2022-09-13 - Earliest claimed: 2018-06-29 - Assignees: Norgren Kloehn, Inc. - Applicants: Norgren Kloehn LLC - Inventors: Dickson Ong - Web page: https://patentgrep.com/patent/US11441550B2 ## CPC - F04B 9/02: the means being mechanical - A61M 5/1452: {pressurised by means of pistons} - F04B 17/03: driven by electric motors - F04B 39/14: Provisions for readily assembling or disassembling - F04B 53/143: {Sealing provided on the piston} - A61M 5/1456: {with a replaceable reservoir comprising a piston rod to be moved into the reservoir, e.g. the piston rod is part of the removable reservoir} - F04B: POSITIVE-DISPLACEMENT MACHINES FOR LIQUIDS; PUMPS (machines for liquids, or pumps, of rotary-piston or oscillating-piston type F04C; non-positive-displacement pumps F04D; pumping of fluid by direct contact of another fluid or by using inertia of fluid to be pumped F04F) - 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)} ## Abstract An apparatus and method of assembling a syringe pump for accurately dispensing a fluid from a syringe. The syringe pump has a frame having a valve assembly connectable to the syringe. A linear rail is disposed in and connected to the frame, and a travel block is disposed within the frame and slidably connected to the linear rail. A connector is connected to the travel block and connectable to the syringe. A power screw having a first end rotatably supported by bearings is disposed within the frame and has a free second end opposite the first end of the power screw wherein the travel block is threadably connected to the power screw. The power screw is rotatably driven to effectively drive the travel block and the connector linearly along the linear rail thereby dispensing the fluid from the syringe. ## Claims ### Claim 1 A syringe pump for accurately dispensing a fluid from a syringe, comprising: a frame having a valve assembly connectable to the syringe; a linear rail disposed in and connected to the frame; a travel block disposed within the frame and slidably connected to the linear rail; a connector connected to the travel block and connectable to the syringe; a power screw having a first end rotatably supported by a floating arrangement of bearings disposed within the frame and a free second end opposite the first end of the power screw, such that the free second end is allowed to move relative to the first end supported by the floating arrangement of bearings to allow the power screw to be aligned relative to the linear rail, wherein the travel block is threadably connected to the power screw, and wherein the floating arrangement of bearings comprises: (i) a fixed bearing housing disposed within the frame about the first end of the power screw, (ii) a first bearing housed within the fixed bearing housing, and (iii) a second bearing housed within the fixed bearing housing axially-apart from the first bearing along a longitudinal axis of the power screw; and the power screw being rotatably driven to effectively drive the travel block and the connector linearly along the linear rail thereby dispensing the fluid from the syringe. ### Claim 2 (depends on 1) The syringe pump stated in claim 1, further comprising: a motor driven pulley connected to the power screw for rotatably driving the power screw. ### Claim 3 (depends on 2) The syringe pump as stated in claim 2, wherein the motor driven pulley provides a substantially cylindrical toothed pulley and a pulley belt for engaging and driving the toothed pulley. ### Claim 4 (depends on 3) The syringe pump as stated in claim 3, wherein the cylindrical toothed pulley is connected to the power screw adjacent the bearings. ### Claim 5 (depends on 1) The syringe pump as stated in claim 1, wherein the travel block further provides a substantially L-shaped structure having a base and a side wherein the base is substantially perpendicular to the side, and the base and side are disposed within housing. ### Claim 6 (depends on 5) The syringe pump as stated in claim 5, wherein an extended portion is connected to and extends from the base and is connected to the connector. ### Claim 7 (depends on 1) The syringe pump as stated in claim 1, wherein a side of the travel block is connected to a carriage, and the carriage is slidably connected to the linear rail to support linear movement of the connector. ### Claim 8 (depends on 1) The syringe pump as stated in claim 1, wherein the power screw has a stopper mounted about and threadably attached to the power screw, such that the stopper radially surrounds the power screw and the power screw extends through the stopper. ### Claim 9 (depends on 8) The syringe pump as stated in claim 8, wherein a base of the travel block has an aperture extending axially therethrough such that both the power screw and the stopper are axially received by the aperture, and connecting the stopper to the travel block thereby allowing the travel block to travel linearly along the linear rail upon rotation of the power screw. ### Claim 10 (depends on 8) The syringe pump as stated in claim 8, wherein a pair of adjoining surfaces establish datums for enhancing the accuracy of the syringe pump. ### Claim 11 (depends on 10) The syringe pump as stated in claim 10, wherein the pair of adjoining surfaces are located on the linear rail and the frame wherein the pair of adjoining surfaces are machined to establish machine datums and enhance the accuracy of the alignment between the linear rail and the frame. ### Claim 12 (depends on 10) The syringe pump as stated in claim 10, wherein the pair of adjoining surfaces are located on the side of the travel block and a carriage wherein the pair of adjoining surfaces are machined to establish machine datums and enhance the accuracy of the alignment between the side of the travel block and the carriage. ### Claim 13 (depends on 1) The syringe pump as stated in claim 1, wherein the first end of the power screw rotatably supported by the floating arrangement of bearings is an upper end, and the free second end of the power screw is a lower end located vertically below the first end. ### Claim 14 (depends on 1) The syringe pump as stated in claim 1, wherein the valve assembly has at least one port communicable with the syringe. ### Claim 15 (depends on 14) The syringe pump as stated in claim 14, further comprising: a first motor having a first output shaft configured to drive the power screw; and a second motor having a second output shaft configured to rotate the valve assembly to select and position the at least one port, and wherein the first output shaft is perpendicular to the second output shaft. ### Claim 16 A method for assembling a syringe pump that accurately dispenses fluid from a syringe while simplifying the assembly of the syringe pump, comprising the steps of: providing a frame with a valve assembly connectable to one end of the syringe; connecting a linear rail to the frame wherein the linear rail has a carriage slidably connected thereto and is disposed within the frame; connecting a travel block to the carriage; connecting a stopper, threadably attached to a power screw, to the travel block; mounting a first end of the power screw to a floating arrangement of bearings disposed within the frame and comprising: (i) a fixed bearing housing disposed within the frame about the first end of the power screw, (ii) a first bearing housed within the fixed bearing housing, (iii) and a second bearing housed within the fixed bearing housing axially-apart from the first bearing along a longitudinal axis of the power screw, wherein mounting the first end of the power screw to the floating arrangement of bearings comprises allowing the first bearing and the second bearing to float into position to allow a second opposite end of the power screw to hang freely and move relative to the first end to provide proper alignment of the power screw relative to the linear rail; providing a motor driven pulley connected to the power screw for rotating the power screw and driving the travel block and the carriage along the power screw and the linear rail; and connecting a connector to the travel block wherein the connector is connectable to a second end of the syringe. ### Claim 17 (depends on 16) The method of claim 16, further comprising the steps of: providing a pair of adjoining surfaces establish datums for enhancing the accuracy of the syringe pump. ### Claim 18 (depends on 17) The method of claim 17, wherein providing the pair of adjoining surfaces further comprises the steps of: machining a machine datum surface on the frame and on the linear rail; and connecting the machine datum surface of the frame to the machine datum surface of the linear rail. ### Claim 19 (depends on 17) The method of claim 17, wherein providing the pair of adjoining surfaces further comprises the steps of: machining a machine datum on a side of the travel block and on the carriage; and connecting the machine datum surface on the side of the travel block to the machine datum surface of the carriage.