Dynamic lead screw thread engagement system and method
First Claim
1. A system for aligning threads of a lead screw with threads of a screw drive mechanism, the screw drive mechanism operating to translate rotational motion of the lead screw into linear motion when their threads are fully engaged with each other, the system comprising:
- a motor coupled to the lead screw that selectively rotates the lead screw;
a plunger driver coupled to the screw drive mechanism to selectively engage a syringe plunger for movement of the plunger in response to movement of the screw drive mechanism;
a position sensor that provides a position signal representative of an axial position of the screw drive mechanism along the lead screw;
a release device that disengages the threads of the screw drive mechanism from engagement with the threads of the lead screw thereby allowing an operator to move the screw drive mechanism to a selected position along the lead screw at which the threads of the screw drive mechanism may be re-engaged with the threads of the lead screw; and
a processor that receives position signals from the position sensor and controls the motor to rotate the lead screw to a predetermined rotational position based on the position signals;
wherein, the processor receives a position signal from the position sensor indicative of the position at which an operator is re-engaging the threads of the screw drive mechanism with the threads of the lead screw; and
the processor controls the motor to rotate the lead screw to a rotational position at which the threads of the lead screw are aligned with the threads of the screw drive mechanism at the selected position.
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Accused Products
Abstract
A system and method for automatically aligning the threads of a lead screw with the threads of a screw drive mechanism, the screw drive mechanism operating to translate the rotational motion of the lead screw into linear motion to expel the contents of a mounted syringe. The system comprises a driver position sensor for determining the position of the screw drive mechanism along the lead screw and a processor for receiving position signals from the driver position sensor, for determining a requisite rotation of the lead screw to ensure alignment of the two sets of threads, and for effectuating the requisite rotation of the lead screw to achieve that alignment. An automatic calibration routine is included that checks for variances in calibration of the system and if found, updates a conversion factor to restore accuracy. Various sensors are used to monitor the operation of components.
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Citations
12 Claims
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1. A system for aligning threads of a lead screw with threads of a screw drive mechanism, the screw drive mechanism operating to translate rotational motion of the lead screw into linear motion when their threads are fully engaged with each other, the system comprising:
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a motor coupled to the lead screw that selectively rotates the lead screw; a plunger driver coupled to the screw drive mechanism to selectively engage a syringe plunger for movement of the plunger in response to movement of the screw drive mechanism; a position sensor that provides a position signal representative of an axial position of the screw drive mechanism along the lead screw; a release device that disengages the threads of the screw drive mechanism from engagement with the threads of the lead screw thereby allowing an operator to move the screw drive mechanism to a selected position along the lead screw at which the threads of the screw drive mechanism may be re-engaged with the threads of the lead screw; and a processor that receives position signals from the position sensor and controls the motor to rotate the lead screw to a predetermined rotational position based on the position signals; wherein, the processor receives a position signal from the position sensor indicative of the position at which an operator is re-engaging the threads of the screw drive mechanism with the threads of the lead screw; and the processor controls the motor to rotate the lead screw to a rotational position at which the threads of the lead screw are aligned with the threads of the screw drive mechanism at the selected position. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11)
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12. A method for aligning threads of a lead screw with threads of a screw drive mechanism, the screw drive mechanism operating to translate rotational motion of the lead screw into linear motion when their threads are fully engaged with each other, the method comprising:
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selectively rotating the lead screw; selectively engaging a syringe plunger with a plunger driver coupled to the screw drive mechanism for movement of the syringe plunger in response to movement of the screw drive mechanism; sensing an axial position of the screw drive mechanism along the lead screw with a position sensor that provides a position signal representative thereof; disengaging the threads of the screw drive mechanism from engagement with the threads of the lead screw with a release device that thereby allows an operator to move the screw drive mechanism to a selected position along the lead screw at which the threads of the screw drive mechanism may be re-engaged with the threads of the lead screw; and controlling the motor to rotate the lead screw to a predetermined rotational position based on the position signal; wherein the position signal is indicative of the position at which an operator is re-engaging the threads of the screw drive mechanism with the threads of the lead screw; and controlling the motor includes rotating the lead screw to a rotational position at which the threads of the lead screw are aligned with the threads of the screw drive mechanism at the selected position.
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Specification