Self-compensating chucking device for infusion pump systems

A self-compensating chucking device may be provided. The chucking device may form a portion of a latching door handle of a door of an infusion pump. The door and a housing of the infusion pump may form a clam-shell clamp that secures infusion tubing to pumping mechanisms of the infusion pump. The latching door handle may include a latching door mechanism that includes a tapered pin. The tapered pin may extend through an outer portion of a door housing, an opening in a handle of the door, and into an opening in an inner portion of the door housing. The opening in the handle of the door may have a tapered inner surface that corresponds to the taper of the tapered pin to form the chucking device. The pin may include a groove configured to accept an E-clip that retains the tapered pin within the door housing.

BACKGROUND

Technical Field

The present disclosure generally relates to the administration of medical fluid by infusion and, in particular, relates to systems and methods of securing infusion tubing to an infusion pump for providing and pumping medical fluid.

Background

Infusion pumps have become commonplace within the healthcare industry as a devices for precisely administering intravenous (IV) fluids. Use of a pump in place of an elevated fluid container with a simple roller clamp to control the flow of the IV fluid allows more accurate and consistent control of the rate of delivery of the fluid to the patient.

The assembly of tubing, valves, fittings, and needles that connect the fluid container to the patient may be referred to as an “IV set.” IV sets are typically disposable to reduce the risk of infection and contamination. When used with an infusion pump, the IV set includes a segment intended to be manipulated by the pump to cause the fluid to flow at a controlled rate. For a peristaltic type of pump, this may be as simple as a length of tubing that is captured between two halves of a clam-shell style pumping mechanism to fit the tubing into a pumping compartment.

SUMMARY

An improved latching door mechanism is provided. The improved latching door mechanism may be provided for a clam-shell door for capturing IV tubing in an intravenous infusion pump system for secure, reliable, positioning of the tubing over many uses of the pump system. The latching door mechanism may include a latch having a self-adjusting chucking mechanism that helps ensure secure, reliable latching of the door over the lifetime of the pump. The latching door mechanism may include a tapered pin configured to support, mechanically retain, and allow rotational pivoting of a latching door handle, by interaction with a complimentary tapered hole mating interface.

Certain exemplary embodiments of the present disclosure include an infusion pump, including: a housing; at least one pumping mechanism; and a pivoting door configured to close and latch to secure infusion tubing to the at least one pumping mechanism, wherein the pivoting door includes: a handle having recess and an opening in the recess; a door housing having an inner portion and an outer portion; and a tapered pin that extends through an opening in the outer portion, a co-aligned opening in the recess of the handle, and a co-aligned opening in the inner portion.

In another embodiment, a latching door handle assembly for a door of an infusion pump is disclosed that includes a molded handle having a hook portion with a recess and a tapered opening in the recess; and a tapered pin, wherein the tapered pin includes: a tapered portion configured to engage in the tapered opening; and a groove configured to receive an E-clip disposed in the recess.

In another embodiment, a fluid infusion system is provided that includes: an intravenous (IV) set having IV tubing; and an IV pump having a pumping module and a door, wherein a pumping segment of the IV tubing is secured to the pumping module by the door, and wherein the door includes: a door housing having an outer portion, an inner portion, and an air gap between the outer portion and the inner portion; a handle having a tapered opening disposed in the air gap; and a latching door handle assembly that includes a tapered pin that extends through an opening in the outer portion, through the tapered opening in the air gap, and into a co-aligned opening in the inner portion.

DETAILED DESCRIPTION

It is to be understood that the present disclosure includes examples of the subject technology and does not limit the scope of the appended claims. Various aspects of the subject technology will now be disclosed according to particular but non-limiting examples. Various embodiments described in the present disclosure may be carried out in different ways and variations, and in accordance with a desired application or implementation.

While the following discussion is directed to the administration of medical fluid to a patient by a nurse using an IV pump, the disclosed methods and configurations may be used for other medical and non-medical applications and may be used by other individuals, for example a patient self-administering a medical fluid at home.

FIG. 1is a diagram of a system100for administering medical fluid to a patient10using an IV pump12. As shown inFIG. 1, a fluid container14may be hung at or above the patient's head and connected via an IV set18to an IV pump12and then to the patient10. In this example, the IV pump12includes a control module16and a pumping module20. A portion of IV set18may be secured to pumping module20by a door30. Door30may be a pivoting door that is rotatable about hinge portions60and may be provided with a latching mechanism37operable to securely fasten door30in a closed position to secure the portion of the IV set in position for pumping. Latching mechanism37may also be operable to release door30so that door30can pivot to an open position to release IV set18.

FIG. 2illustrates a pumping segment17of IV set18that may be secured into the pump module20of the IV pump12ofFIG. 1. In this example, pumping element17is a length of the tubing of IV set18. The pumping module20is shown with its front door30opened and the inner surface21of door30and the pumping actuators19of pump module20visible. When installed, the pumping element17is located against the pumping actuators19and door30can be closed and latched using an internal member23of latch37to secure pumping element17against pumping actuators19. Pumping actuators19may be operated to sequentially compress portions of pumping element17to apply force to the fluid and sequentially advance fluid toward the patient10at a controlled flow rate.

An exemplary implementation of infusion pump12is shown inFIGS. 3A, 3B, 4A and 4B. As shown inFIGS. 3A, 3B, 4A and 4B, an infusion pump of a fluid infusion system may include a housing27which accommodates one or more pumping mechanisms (e.g., a cam mechanism that controls a plurality of fingers of a peristaltic pumping mechanism, an electric motor and associated gearing that drive said cam mechanism) and further accommodates electronic control and processing circuitry for controlling the pumping mechanisms and processing signals (e.g., from pressure sensors, etc.) provided on the unit.

The pump unit12, as shown inFIGS. 4A and 4B, may also include an electronically operated display52, an alarm light54, an input keyboard56or other manually operated controls. The rear of the unit12(not shown) may be provided with various connectors including connectors for receiving complementary power supply connectors, electronic communications interfacing connectors for providing data and alarm output signals and for receiving input signals, and/or mechanical supports.

In the example ofFIG. 3A, the front of the housing27includes a face or deck29on which is exposed an upper mounting or bracket22for a complementary fitting38forming part of an infusion line; a lower mounting or bracket24for a complementary fitting40forming part of such infusion line and a peristaltic assembly26which is, effectively, the operative end of the peristaltic pumping mechanism and may, in principle, be the free ends of respective fingers moveable, by the cam mechanism referred to, inwards and outwards from the face or deck29.

In order to make it easier to maintain sterile conditions, these fingers may be covered by a thin flexible membrane (not shown) sealed at its edges with respect to the deck29. Door30is may be fitted to the housing27and can be swung between an open position illustrated inFIGS. 3A and 3Band a closed position illustrated inFIGS. 4A and 4B, about a pivotal axis A.

A medical fluid infusion line, for use with the pump unit, may include upper and lower sections32and34respectively of transparent (e.g., plastic) tubing, an intermediate section36of resiliently compressible tubing, (e.g., formed from silicone rubber), and upper and lower fittings38and40via which the tubing section36is connected respectively with the upper line32and with the lower line34. In use, the upper line32may extend upwardly to a source14of the medical fluid to be administered and the lower line34may extend from the infusion pump to an infusion needle or catheter or the like inserted into the patient10. In use, the infusion line may be extended across the face or deck29of the pump unit so that the fittings38and40are received in the brackets22and24respectively and so that the tubing section36extends over the peristaltic assembly26as illustrated inFIGS. 3A and 3B.

The infusion line may be fitted in place in this fashion while door30is in the open position shown inFIGS. 3A and 3B. After the infusion line has been so fitted, door30may be moved to the closed position shown inFIG. 4Aand secured using catch37which comprises a lever mounted on the outer edge of the door30(e.g., the edge which lies at the side of the pump unit when the door is in its closed position), by a pin300for pivoting about an axis B (see, e.g.,FIG. 4A) that is generally perpendicular to that outer edge of the door and parallel with the front face of the door.

As shown inFIG. 4A, catch37may have a handle portion37bwhich extends downwardly and into a pocket in the front of the door30. Catch37may also include a cam portion (described in further detail hereinafter) adapted to fit within a complementary recess39, in deck29and obscured by the outer housing27, at the front right of the pump housing adjacent side of the pump.

The cam portion of the catch37may have a cam surface502, (seeFIG. 5), configured to engage under an internal yoke boss41or other corresponding cam feature (which projects laterally from the pump housing into recess39) when, with the pump door30closed, the handle portion37bis swung downwardly and rearwardly from a position in which it projects forwards and outwards from the door (FIG. 4A) to a position in which the handle portion37blies against the front of the door (FIG. 4B).

In operation of the pump, the fingers of the peristaltic assembly26periodically press the flexible resilient tubing against a counter surface or anvil to propel fluid within the infusion line along the latter. In one exemplary implementation of the pump, the peristaltic assembly comprises an upper finger and a lower finger, which are of a relatively limited extent in the longitudinal direction of the infusion line, and an intermediate finger or pad, between the upper and lower fingers, in which the intermediate finger is extended or elongated in the longitudinal direction of the infusion line.

In operation, assuming the fluid is to be propelled downwards, as viewed inFIGS. 1 to 4B, along the infusion line, the peristaltic assembly performs a repeating cycle in which, with the intermediate pad spaced from the counter surface, the upper finger presses the flexible tube against the counter surface or anvil to close the tube at the location of the upper finger, the lower finger is then withdrawn from the counter surface to open the tube at the location of the lower finger. Then the intermediate pad or finger is then moved towards the counter surface to drive the fluid in the tube adjacent the intermediate pad downward along the tube, and then the tube is pinched closed again between the lower finger and the counter surface. The upper finger is then withdrawn from the counter surface and the intermediate finger withdrawn from the counter surface to draw fresh fluid into the part of the tube adjacent the intermediate finger. It should be appreciated that the pumping mechanisms described above in connection withFIGS. 3A-4Bare merely illustrative. Other pumping arrangements or mechanisms can be used to pump fluid through infusion tubing (or any other portion of an IV set such as an infusion cassette) that is secured to the pumping mechanisms by a pivoting clam-shell door that is controllable and latchable using a latch mechanism as described herein.

FIG. 5shows an example of a door assembly30having an improved latching door mechanism with a tapered pin300designed to support, mechanically retain and allow rotational pivoting of a latching door handle37b, with a complimentary tapered hole mating interface530in the door handle. Tapered pin300may be formed from a hardened steel in one embodiment (e.g., an AISI Type 303 Stainless Steel).

An intravenous infusion pump may operate by capturing a fluid delivery tube between two halves of a clam-shell-style pumping mechanism. One half of this clam-shell pump configuration may be a base assembly that houses the primary electro-mechanical pump elements, hinge mounting points to support a door assembly, features that capture and locate the fluid delivery tube and a yoke catch that engages a latching door handle for snug door closure.

Door assembly30ofFIG. 5may be coupled to housing27of an infusion pump at hinge points60to form the second half of a clam-shell pump configuration that mounts to, and rotates about, the hinge mounting points of the other half of the clam shell formed by the housing27. Door assembly30may include, on a rear side (not shown) complimentary features to the pump features of the housing that capture and locate the fluid delivery tube along the mechanical pump elements. Door assembly30may include a rotationally pivoted latching door handle37bthat mates with the yoke clamp of the housing, thus allowing this snug door closure.

Tapered pin300, when installed in the door latch assembly may span an air gap511of a rectangular shaped aperture in the door assembly's housing504at which the latching door handle37bis located and supported. The air gap511may be disposed between an inner portion520and an outer portion522of door housing504. During assembly, the tapered pin300may be inserted through a series of mating holes in the following order: a through-hole508in outer portion522, a matching, co-aligned tapered hole530in the hook portion500of the latching door handle37b, and a co-aligned blind hole510in the inner portion520of door housing504.

Door handle37bmay be a sintered steel handle such as a molded sintered stainless steel handle with a molded hook500and a recess540. Opening530may be disposed in recess540and may have a tapered inner surface that corresponds to the shape of a tapered outer surface of tapered pin300. The tapered inner surface of opening530may have tapered opening angle531with an approximately 2 degree taper moving inward in a direction from outer portion522toward inner portion520of housing504, when door assembly30is assembled. A taper interface (e.g., a 2.0 degree taper interface) may be formed from the inclined contact surface having a tapered portion angle301made between the tapered pivot latch pin300and the interior surface of opening530of hook portion500having a tapered opening angle531. Side torque applied to the door handle37bduring closing generates a chucking force along this inclined tapered surface temporarily binding the pivot latch pin and hook together. Simultaneous downward rotation during this “chucking” enables the door handle to properly engage the pump housing thus enabling door closure.

Door housing504may be formed from plastic and may include co-aligned openings508and510, respectively, in outer portion522and inner portion520. An inner wall of outer portion522and an outer wall of inner portion520may form opposing surfaces of the aperture511within which pin300engages hole530of handle37b.

As shown, a wear protection washer such as washer512and the coil of a torsion spring such as spring514may be disposed in recess540when door assembly30is assembled. In the example ofFIG. 5, washer512includes a retention tab513that keys the washer into a gap between recess540(e.g., a latch handle spring pocket) and spring514. However, this is merely illustrative. In some embodiments, washer512may be implemented as a flat washer. According to an embodiment, torsion spring514extends around the tapered opening in recess540, washer512is disposed on the tapered pin, and E-clip retainer506disposed in the e-clip groove602between torsion spring514and the wear protection washer512.

As shown in the exploded perspective view of latching door handle assembly650ofFIG. 6, features along the body of tapered pin300may be provided to securely retain and establish the rotational datum of the latching door handle37bwithin the door housing504. These tapered pin features include the tapered profile geometry of a tapered portion600of the pin300and an E-clip groove602.

Tapered section600of pin300may be configured to mate with a matching tapered inner surface of opening530in the hook portion500of the latching door handle37b. As a turning force is applied to the handle37b, in the un-latched position, to close the door, these two tapered mating features are pushed together (e.g., by a lateral force generated along the tapered interface by turning the handle as the door latch cam surface502of handle37band a corresponding cam feature in the pump housing are moved into alignment preceding the downward handle cam latching upon a housing catch such as a yoke boss) thereby generating a binding axial friction between pin300and the inner surface of opening530that binds the pin300and handle37btogether along this tapered interface.

During closure, as the door is turned, engagement with the internal components of the pump that capture the tube set resist this door closure, prompting an increase in side turning force to allow alignment of the cam latching elements. Turning force on the door handle37b, to overcoming the resistance of the internal components of the pump, generates the binding axial friction along the tapered interface600and the matching tapered inner surface of opening530that temporarily locks the pin300and latch door handle37btogether creating a stable rotational pivot axis. This stable pivot axis enables smooth aligned motion between hook500of latching door handle37band the yoke catch (e.g., a boss) of the housing when the handle is pushed (e.g., downward) to close and latch the door30.

E-clip groove602may be a recess having a complementary shape for accepting E-Clip retainer506. E-clip retainer506, when engaged in groove602in pin300, provides a mechanical stop that prevents tapered pin300from backing out of door housing504during normal operation. When door assembly30is assembled, E-clip506is located along the tapered pin300near the inner surface of the outer portion522of the door housing aperture511. A washer512may be placed between E-Clip506and the inner surface of outer portion522to provide a smooth surface that protects E-clip506from damage caused by chaffing against the door housing inner wall. E-clip retainer506may, for example, be a Rotoclip® retainer in some embodiments.

For ease of removal from door housing504during maintenance and repair operations, a threaded extraction hole604may be provided at the exposed end of tapered pin300. A threaded rod or tool can be inserted into this hole604and used to pull pin300out of the door housing504. The extraction hole604may be provided with an internal thread (e.g., a #2-56 UNC-2B internal thread). In this way, the extraction hole604allows one to pull symmetrically along the tapered pin's axis, enabling easy extraction of the pin during repair or maintenance operations. E-Clip retainer506may be removed before engaging the hole604to remove the pin300.

As shown inFIG. 6, handle37bmay include one or more latching extensions such as latching extensions620. Latching extensions620may extend into or below a portion of housing27and engage with corresponding mating features of the tube set as part of the infusion tube set functionality in accordance with the pumping mechanisms of pump12.

Pin300may be provided with e-clip recess602and without any additional recess as in the example ofFIG. 6. Latching extensions620are shown inFIG. 6along with mating features629for latching extensions620on an interior side of handle37b.

FIG. 7is a cross-sectional top view of the latch assembly of door30in an assembled configuration, in accordance with an embodiment. In the example ofFIG. 7, pin300extends through opening508in outer portion522of housing504, through opening530in recess540, and partially into opening510in inner portion520of housing504. As shown in the example ofFIG. 7, opening510may be a blind hole in inner portion520. Also shown inFIG. 7is washer512disposed between the door housing wall700and E-clip retainer506along tapered pivot latch pin300. In this configuration, washer512prevents contact between door wall700and E-clip506and provides a smooth surface for E-clip506to oscillate against, thereby reducing or eliminating E-Clip stretch wear.

As shown inFIG. 7, pin300may be provided with a wear-relief feature such as wear-relief chamfer704that prevents pin300from coming into contact with the inner wall706of housing504if, over time, pin creep is present. For example, in configurations in which pin300is a hardened steel pin and hook portion500is formed from a relatively softer molded sintered steel, pin creep may arise when the hardened steel tapered pin is pushed into the relatively softer sintered steel hook, during “chucking”, thereby deforming the hook's tapered hole530. However, the tapered interface formed by tapered portion600and the inner surface of tapered hole530may provide a self-compensating chucking device that self-compensates for pin creep by allowing pin300to move deeper into hole530such that a wider portion of the tapered surface of pin300engages the deformed hole530to provide the same binding friction.

As shown inFIG. 7, an air gap702may be provided between the inner end708of pin300and the bottom710of opening510that allows pin300to move deeper into openings530and510without the pin bottoming out in opening510. As shown, the tapered portion of the tapered pin300is partially disposed in the opening530in the recess540of the handle37band extends from the opening530in the recess540of the handle37binto the recess540so that the tapered portion600can move further into opening530in the presence of pin creep.

Wear-relief chamfer704may, for example, be a 10-15 mil chamfer that can accommodate, for example, 3-5 mils of wear over the lifetime of assembly650. As shown inFIG. 7, wear-relief chamfer704may be disposed adjacent an inner edge of the opening530in the recess540of the handle37b.

The tapered interface between pin300and opening530may thus establish a stable, self-centering, self-compensating, axial alignment between the chucking assembly's mating components thereby allowing smooth repeatable motion of door handle37bover repeated opening and closing of door30.

FIG. 8is an enlarged view of a portion of pin300engaged in opening530in hook portion500. Other portions of door assembly30are omitted fromFIG. 8to facilitate viewing of tapered interface800formed from the outer surface of tapered portion600of pin300and the inner surface of opening530. As shown by dashed lines806A and806B, tapered interface800may define a taper of angle α. Angle α may, for example, be a two-degree angle, an angle of less than two degrees (e.g., a one-degree angle, a 1.5 degree angle, or a 1.8 degree angle), or an angle of more than two degrees (e.g., a 2.5 degree angle, a three degree angle, a four degree angle, or a five degree angle).

Contact at the interface800along a length of tapered portion600may also prevent or limit lateral play of pin300within opening530so that a perpendicular bisector (e.g., as indicated by arrow804) of the outer surface of portion600that passes through the axis of pin300is not displaced, even in the presence of forces on pin300that would otherwise cause non-axial rotation of pin300within opening530.

The frictional binding load generated by the chucking tapered interface800(as indicated, for example, by arrows802) may provide the advantages over conventional systems of eliminating the need for a thread-lock adhesive and providing a tapered interface that breaks away easily when the assembly is relaxed and in a non-chucking state allowing the assembly to be separable and thereby enabling reuse of components (as examples).

FIG. 9is a cross-sectional top view of the latch assembly of door30in an assembled configuration and showing various load forces on the assembly, in accordance with an embodiment. The example ofFIG. 9is a free body diagram showing how the “chucking” effect is generated. The cross-section ofFIG. 9shows a cross-section of the portion of pump module20referenced by the dashed circle459shown inFIG. 4A.

As shown inFIG. 9, a handle closure load900may be generated on handle37bduring closing that pushes outwardly on the handle. However, pin300, in cooperation with e-clip506, provide a pin counter force902in opposition to the load900, thus generating the tapered interface chucking force indicated by arrows802. In this way, the tapered pin and the tapered opening are configured such that a door closing force on the door that is sufficient to overcome resistance from internal components of the IV pump that capture the IV tubing and sufficient to place the cam surface in alignment with the corresponding cam feature generates a lateral force along the tapered pin and tapered opening that pushes an outer tapered surface of the tapered pin into and along a tapered inner surface of the tapered opening causing chucking or binding.

The tapered pin and the tapered opening can thus be configured to continuously slide along a tapered inclined interface to compensate for wear and maintain a binding or chucking condition that absorbs slackness or looseness resulting from a gradual wear of the tapered opening by contact with the tapered pin.

Extraction hole604may provide for ease of disassembly during door maintenance and may provide a unique identity feature for pin300. Moreover, a tapered interface configuration as described herein is difficult to counterfeit as the mating component's taper geometry is tightly controlled during the machining processes. As such, deviations from the specified tolerances between tapered mating parts will prevent proper component interaction and mechanism function.

The subject technology is illustrated, for example, according to various aspects described above. Various examples of these aspects are described as numbered concepts or clauses (1, 2, 3, etc.) for convenience. These concepts or clauses are provided as examples and do not limit the subject technology. It is noted that any of the dependent concepts may be combined in any combination with each other or one or more other independent concepts, to form an independent concept. The following is a non-limiting summary of some concepts presented herein:

Concept 1. An infusion pump, comprising:a housing;at least one pumping mechanism; anda pivoting door configured to close and latch to secure infusion tubing to the at least one pumping mechanism, wherein the pivoting door comprises:a handle having recess and an opening in the recess;a door housing having an inner portion and an outer portion; anda tapered pin that extends through an opening in the outer portion, a co-aligned opening in the recess of the handle, and a co-aligned opening in the inner portion.

Concept 2. The infusion pump of Concept 1 or any other Concept, wherein the opening in the recess of the handle comprises a tapered opening having a tapered inner surface with a taper that corresponds to a taper of the tapered pin.

Concept 3. The infusion pump of Concept 2 or any other Concept, wherein the tapered pin comprises a tapered portion and a cylindrical portion and wherein the cylindrical portion is disposed within the opening in the outer portion of the door housing.

Concept 4. The infusion pump of Concept 3 or any other Concept, wherein the tapered portion of the tapered pin is partially disposed in the opening in the recess of the handle and extends from the opening in the recess of the handle into the recess.

Concept 5. The infusion pump of Concept 4 or any other Concept, wherein the tapered pin further comprises a groove disposed between the cylindrical portion and the tapered portion.

Concept 6. The infusion pump of Concept 5 or any other Concept, further comprising an E-clip retainer engaged in the groove that provides a mechanical stop that prevents the tapered pin from backing out of door housing.

Concept 7. The infusion pump of Concept 6 or any other Concept, wherein the tapered pin comprises a wear-relief chamfer adjacent an edge of the opening in the recess of the handle.

Concept 8. The infusion pump of Concept 7 or any other Concept, further comprising an air gap between an end of the tapered pin and a bottom of the opening in the inner portion of the door housing.

Concept 9. The infusion pump of Concept 8 or any other Concept, further comprising a washer disposed between the E-clip retainer and an inner wall of the outer portion of the housing.

Concept 10. The infusion pump of Concept 1 or any other Concept, wherein the tapered pin comprises a tapered portion having a taper of approximately two degrees.

Concept 11. The infusion pump of Concept 10 or any other Concept, wherein the opening in the recess of the handle comprises a corresponding taper of approximately two degrees.

Concept 12. The infusion pump of Concept 1 or any other Concept, wherein the handle comprises a sintered steel handle and wherein the tapered pin comprises a relatively harder hardened steel pin.

Concept 13. The infusion pump of Concept 12 or any other Concept, wherein the handle comprises a hook portion, wherein the recess is disposed in the hook portion, and wherein the hook portion comprises a cam surface.

Concept 14. The infusion pump of Concept 13 or any other Concept, further comprising a boss disposed on the housing, the boss configured to engage with the cam surface of the hook portion of the handle to press the tapered pin into the opening in the recess in the hook portion when the cam surface is pressed against the boss by a closing force on the handle.

Concept 15. The infusion pump of Concept 1 or any other Concept, further comprising a threaded extraction hole in the tapered pin.

Concept 16. A latching door handle assembly for a door of an infusion pump, comprising:a molded handle having a hook portion with a recess and a tapered opening in the recess; anda tapered pin, wherein the tapered pin comprises:a tapered portion configured to engage in the tapered opening; anda groove configured to receive an E-clip disposed in the recess.

Concept 17. The latching door handle assembly of Concept 16 or any other Concept, further comprising a cam surface on the hook portion, wherein the cam surface is configured to transfer a force on the cam surface into a force that presses the tapered pin into the tapered opening.

Concept 18. The latching door handle assembly of Concept 16 or any other Concept, further comprising:a torsion spring that extends around the tapered opening in the recess; anda washer on the tapered pin; andthe E-clip disposed in the groove between the torsion spring and the washer.

Concept 19. A fluid infusion system, comprising:an intravenous (IV) set having IV tubing; andan IV pump having a pumping module and a door, wherein a pumping segment of the IV tubing is secured to the pumping module by the door, and wherein the door comprises:a door housing having an outer portion, an inner portion, and an air gap between the outer portion and the inner portion;a handle having a tapered opening disposed in the air gap; anda latching door handle assembly that includes a tapered pin that extends through an opening in the outer portion, through the tapered opening in the air gap, and into a co-aligned opening in the inner portion.

Concept 20. The fluid infusion system of Concept 19 or any other Concept, wherein the latching door handle assembly further comprises:a hook portion having a cam surface configured to engage a corresponding cam feature on the pumping module;an E-clip retainer engaged with a recess on the tapered pin;a washer disposed between the E-clip retainer and the outer portion of the door housing; anda torsion spring disposed between the E-clip retainer and a portion of the handle.

Concept 21. The fluid infusion system of Concept 20 or any other Concept, wherein the tapered pin and the tapered opening are configured such that a door closing force on the door that is sufficient to overcome resistance from internal components of the IV pump that capture the IV tubing and to place the cam surface in alignment with the corresponding cam feature generates a lateral force along the tapered pin and tapered opening that pushes an outer tapered surface of the tapered pin into and along a tapered inner surface of the tapered opening causing chucking or binding.

Concept 22. The fluid infusion system of Concept 21 or any other Concept, wherein the tapered pin and the tapered opening are configured to continuously slide along a tapered inclined interface to compensate for wear and maintain a binding or chucking condition that absorbs slackness or looseness resulting from a gradual wear of the tapered opening by contact with the tapered pin.

It is understood that the specific order or hierarchy of steps, or operations in the processes or methods disclosed are illustrations of exemplary approaches. Based upon implementation preferences or scenarios, it is understood that the specific order or hierarchy of steps, operations or processes may be rearranged. Some of the steps, operations or processes may be performed simultaneously. In some implementation preferences or scenarios, certain operations may or may not be performed. Some or all of the steps, operations, or processes may be performed automatically, without the intervention of a user. The accompanying method claims present elements of the various steps, operations or processes in a sample order, and are not meant to be limited to the specific order or hierarchy presented.