Screw drive engagement/disengagement and decoupling mechanism

Claim 3

The apparatus of claim 1 further comprising disengaging means 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.

Claim 4

The apparatus of claim 2 wherein the disengaging means comprises a cam disposed on the half-nut means, and lever means for engaging the cam and causing the threads of the half-nut means to disengage from the threads of the lead screw; and the biasing means is also for opposing the action of the lever to disengage the half-nut means from the lead screw and urging the threads of the half-nut means into re-engagement with the threads of the lead screw upon relaxation of the lever means.

Claim 5

The apparatus of claim 2 further comprising stop means for preventing the disengagement of the threads of the half-nut means from the threads of the lead screw other than by use of the disengagement means.

Claim 6

The apparatus of claim 1 wherein: the half-nut means completely surrounds the lead screw and comprises 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°.

Claim 7

The apparatus of claim 1 wherein the mounting means comprises engagement means for engaging the block means such that rotation of the block means is opposed.

Claim 8

The apparatus of claim 6 wherein the mounting means comprises a tube on which the block means slides in response to traveling of the half-nut means along the lead screw.

Claim 9

The apparatus of claim 1 wherein the angle of the angled surface on the block means is greater than the angle of the threads of the lead screw.

Claim 10

The apparatus of claim 1 wherein the half-nut means also comprises a surface formed on the half-nut which is disposed at an acute angle to the longitudinal axis of the lead screw, the angle being approximately equal to the angle of the angled surface of the block means.

Claim 11

The apparatus of claim 1 further comprising an arm coupled to the block means for transmitting the linear motion of the block means to a remote location.

Claim 12

The apparatus of claim 10 wherein the arm is coupled to the block means by at least one bearing means.

Claim 13

The apparatus of claim 11 wherein the arm is coupled to the block means at two points by bearing means for providing a bearing surface at each point.

Claim 14

The apparatus of claim 10 further comprising disengaging means 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, 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 the biasing means is also for opposing the action of the lever to disengage the half-nut means from the lead screw and for urging the threads of the half-nut means into re-engagement with the threads of the lead screw upon relaxation of the lever means.

Claim 15

The apparatus of claim 13 wherein the stop means comprises: a protrusion having a substantially flat surface formed on the half-nut means; and a striker disposed in the block means for engaging the flat surface of the protrusion to oppose movement of the half-nut means.

Claim 16

The apparatus of claim 14 further comprising: an arm coupled to the block means for transmitting the motion of the block means to a remote location; wherein the disengaging means comprising: a cam disposed on the half-nut means; lever means disposed within the arm for engaging the cam and overcoming the stop means and for causing the threads of the half-nut means to disengage from the threads of the lead screw upon rotating the arm; and the biasing means for urging the cam back into position to re-align the flat surface with the striker and for urging the threads of the half-nut means into re-engagement with the threads of the lead screw upon relaxation of the lever means.

Claim 17

In a syringe pump, a combination comprising: 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.

Claim 18

In a syringe pump, a combination comprising: 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.

Claim 19

The combination of claim 16 wherein the half-nut means completely surrounds the lead screw and comprises 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°.

Claim 20

The combination of claim 17 wherein: the angle of the angled surface on the block means is greater than the angle of the threads of the lead screw; and the half-nut means comprises a surface on which the bearing surface is formed which is disposed at an acute angle to the longitudinal axis of the lead screw, the angle being approximately equal to the angle of the angled surface of the block means.

Claim 21

The combination of claim 16 wherein: the disengaging means comprising a cam disposed on the half-nut means and 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 the biasing means is also for urging the threads of the half-nut means into reengagement with the threads of the lead screw upon relaxation of the lever means.

Claim 22

The combination of claim 16 further comprising stop means for preventing the disengagement of the half-nut from the lead screw other than by use of the disengagement means.

Claim 23

The combination of claim 20 wherein the stop means comprises: a protrusion having a substantially flat surface formed on the half-nut means; and a striker disposed in the block means for engaging the flat surface of the protrusion to oppose movement of the half-nut means.

Claim 24

The combination of claim 21 wherein: the half-nut means comprises a cam; the arm comprises lever means for engaging the cam and overcoming the stop means and for causing the threads of the half-nut means to disengage from the threads of the lead screw upon rotating the arm; and the biasing means is also for urging the cam back into position to re-align the flat surface with the striker and for urging the threads of the half-nut means into reengagement with the threads of the lead screw upon relaxation of the lever means.

Claim 25

The combination of claim 16 wherein the arm is coupled to the block means by at least one bearing means.

Claim 26

The combination of claim 23 wherein the arm is coupled to the block means at two points by bearing means for providing a bearing surface at each point.

Claim 27

In a syringe pump, the combination comprising: 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.

Claim 28

In a syringe pump, the combination comprising: 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.

Claim 29

The combination of claim 25 wherein the arm is coupled to the block means by at least one bearing means.

Claim 30

The combination of claim 26 wherein the arm is coupled to the block means at two points by bearing means for providing a bearing surface at each point.