Screw drive engagement/disengagement and decoupling mechanism
First Claim
1. An apparatus for converting the rotational motion of a threaded lead screw into linear motion, the apparatus comprising:
- half-nut means having threads for engaging the threads of the lead screw around a predetermined arc thereof and traveling along the lead screw in a first direction in response to rotation of the lead screw, the half-nut means comprising a bearing surface protruding in the first direction;
mounting means for providing a mounting surface parallel with the lead screw and along a predetermined extent of the lead screw length;
block means for moving along the mounting means in response to the traveling of the half-nut means along the lead screw, the block means comprising a surface disposed at an acute angle to the longitudinal axis of the lead screw, the angled surface contacting the bearing surface of the half-nut means for urging the threads of the half-nut means into contact with the threads of the lead screw during rotation of the lead screw; and
biasing means for urging the half-nut means into contact with the lead screw during periods of rotation and non-rotation of the lead screw.
13 Assignments
0 Petitions
Accused Products
Abstract
A half-nut block containing a threaded bore and a larger, overlapping, unthreaded bore is engaged with a lead screw. The larger bore overlaps the threaded bore so that effectively a half-nut results. The half-nut comprises a face having an acute angle in relation to the lead screw and this angled face contacts the inside of a bearing block within which the half-nut is mounted. The bearing block is slidably mounted on a C-tube which is mounted around and extends along a predetermined length of the lead screw. Also mounted on the C-tube is an arm for transmitting the linear motion of the bearing block to a remote point such as the plunger of a syringe. The arm is coupled to the bearing block at points selected so that transmission to the arm of any wobbling of the bearing block is reduced. The arm includes a lever which engages a cam formed on the half-nut to force the half nut to disengage from the lead screw when the arm is to be moved to a new location on the lead screw. A spring bias is coupled to the half-nut block opposite the cam for urging the half-nut block back into contact with the lead screw after disengagement. A stop mechanism prevents undesired disengagement of the half-nut block from the lead screw when force is applied other than by the cam block.
54 Citations
27 Claims
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1. An apparatus for converting the rotational motion of a threaded lead screw into linear motion, the apparatus comprising:
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half-nut means having threads for engaging the threads of the lead screw around a predetermined arc thereof and traveling along the lead screw in a first direction in response to rotation of the lead screw, the half-nut means comprising a bearing surface protruding in the first direction; mounting means for providing a mounting surface parallel with the lead screw and along a predetermined extent of the lead screw length; block means for moving along the mounting means in response to the traveling of the half-nut means along the lead screw, the block means comprising a surface disposed at an acute angle to the longitudinal axis of the lead screw, the angled surface contacting the bearing surface of the half-nut means for urging the threads of the half-nut means into contact with the threads of the lead screw during rotation of the lead screw; and biasing means for urging the half-nut means into contact with the lead screw during periods of rotation and non-rotation of the lead screw. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15)
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16. In a syringe pump, a combination comprising:
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a threaded lead screw; half-nut means having threads for engaging the threads of the lead screw around a predetermined arc thereof and traveling along the lead screw in a first direction in response to rotation of the lead screw, the half-nut means comprising a bearing surface protruding in the first direction; mounting means for providing a mounting surface parallel with the lead screw and along a predetermined extent of the lead screw length; block means for moving along the mounting means in response to the traveling of the half-nut means along the lead screw and for engaging the block means such that rotation of the block means is opposed, the block means comprising a surface disposed at an acute angle to the longitudinal axis of the lead screw, the angled surface contacting the bearing surface of the half-nut means for urging the threads of the half-nut means into contact with the threads of the lead screw during rotation of the lead screw; biasing means for urging the half-nut means into contact with the lead screw during periods of rotation and non-rotation of the lead screw; an arm coupled to the block means for transmitting the motion of the block means to a remote location; and disengaging means coupled to the arm for disengaging the threads of the half-nut means from the threads of the lead screw so that the half-nut means may be moved to a selected position along the lead screw. - View Dependent Claims (17, 18, 19, 20, 21, 22, 23, 24)
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25. In a syringe pump, the combination comprising:
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a threaded lead screw; half-nut means having threads for engaging the threads of the lead screw and for traveling along the lead screw in a first direction in response to rotation of the lead screw, the half-nut means comprising a bearing surface protruding in the first direction, the half-nut means completely surrounding the lead screw and comprising two bores, the first bore being threaded for engagement with the threads of the lead screw threads and the second bore being larger than the lead screw and overlapping the first bore so that the first bore includes an arc of no greater than 180°
;mounting means for providing a mounting surface parallel with the lead screw and along a predetermined extent of the lead screw length; block means for moving along the mounting means in response to the traveling of the half-nut means along the lead screw, the block means comprising a surface disposed at an acute angle to the longitudinal axis of the lead screw, the angled surface contacting the bearing surface of the half-nut means for urging the threads of the half-nut means into contact with the threads of the lead screw during rotation of the lead screw; an arm coupled to the block means for transmitting the motion of the block means to a remote location; disengaging means coupled to the arm for disengaging the threads of the half-nut means from the threads of the lead screw so that half-nut means may be moved to a selected position along the lead screw, the disengaging means comprising; a cam disposed on the half-nut means; lever means disposed within the arm for engaging the cam and causing the threads of the half-nut means to disengage from the threads of the lead screw upon rotating the arm; and biasing means for urging the threads of the half-nut means into contact with the threads of the lead screw during periods of rotation and nonrotation of the lead screw. - View Dependent Claims (26, 27)
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Specification