Patent Description:
Medical treatments often include the infusion of a medical fluid (e.g., a saline solution or a liquid medication) to patients using an intravenous (IV) catheter that is connected though an arrangement of flexible tubing and fittings, commonly referred to as an "IV set," to a source of fluid, for example, an IV bag. Often, tubing, syringes, needles and other medical equipment are made with threaded connectors and/or a universal luer conical fitting that may be tightened to make it leak-free.

In some applications, overtightened connections may be difficult or impossible to remove by hand.

<CIT> discloses fluidic coupling assemblies including a fitting body having a single integral piece or separable pieces such as male and female fittings such as luer fittings. The assemblies further comprise a rotatable fastening assembly having a drive collar and a driven member, and at least one resilient member having a spring bias that defines a threshold torque of the rotatable fastening assembly. The spring bias may be directed axially or radially with respect to the longitudinal axis of the fluidic coupling assembly. The resilient member is configured to prevent overtightening of the fluidic coupling assembly by allowing the drive collar to rotate the driven member only when less than a threshold torque is applied. Rotation of the rotatable fastening assembly imparts a compressive force on the resilient member, and the resilient member yields when the compressive force exceeds the spring bias of the resilient member. <CIT> discloses an interventional medical instrument conveying system comprising a loader provided with a loading tube (<NUM>), a delivery catheter (<NUM>), a stent (<NUM>), a pushing component (<NUM>), and a hemostasis valve (<NUM>). The loading tube (<NUM>) or the delivery catheter (<NUM>) is provided with a position-limiting locking connector (<NUM>). An appropriate-rotation control mechanism (<NUM>) for controlling a tightening degree between a distal end of the loading tube (<NUM>) and a proximal end of the delivery catheter (<NUM>) is disposed outside the loading tube (<NUM>) or the delivery catheter (<NUM>). The proximal end of the delivery catheter (<NUM>) and the distal end of the loading tube (<NUM>) engage with each other in a sealed manner, and are threadingly fixed to each other by means of the position-limiting locking connector (<NUM>). The appropriate-rotation control mechanism (<NUM>) rotates in one direction to appropriately tighten a thread-connection, and rotates in the opposite direction to release the thread-connection. The interventional medical instrument conveying system of the invention has a simple system structure, is easy to operate, and automatically determines a tightening degree. <CIT> discloses a torque-limiting connector including an outer clutch having a plurality of biased outer teeth and an inner clutch configured to fit within the outer clutch, the inner clutch having a plurality of cantilevered inner members. Each of the plurality of cantilevered inner members has an inner tooth, wherein upon the application of a predetermined amount of torque, each of the plurality of biased outer teeth slips over a respective inner tooth. <CIT> discloses a torque limited fitting is provided having a head and a body, which in certain embodiments may be assembled by an operator. The body of the torque limited fitting has a passageway therethrough for receiving and removably holding tubing. The torque limited fitting may be adapted for use with a flat bottom port, such as in an analytical instrument, like liquid chromatography, gas chromatography, ion chromatography, or in in vitro diagnostic systems. <CIT> relates to a connecting structure for medical use.

The disclosed subject matter relates to infusion disposables. In certain embodiments, a torque limiting connector is disclosed that comprises an outer connector comprising a profile disposed on an inner surface of the outer connector; an inner connector disposed within the outer connector, the inner connector comprising: an upper threaded portion; and a lower threaded portion; and a clutch disposed around and rotationally coupled to the inner connector, the clutch comprising a plurality of clutch teeth extending from an outer surface of the clutch, wherein the plurality of clutch teeth are outwardly biased to be releasably engaged with the profile of the outer connector, wherein the plurality of clutch teeth are configured to transfer an operational torque from the outer connector to the inner connector when the operational torque is below a torque limit, and the plurality of clutch teeth are forced inward to disengage the profile of the outer connector and prevent transfer of the operational torque when the operational torque exceeds the torque limit.

In certain embodiments, a torque limiting connector is disclosed that comprises an outer connector comprising a profile disposed on an inner surface of the outer connector; an inner connector disposed within the outer connector, the inner connector comprising: an upper threaded portion; and a lower threaded portion; and a clutch disposed around and rotationally coupled to the inner connector, the clutch comprising a plurality of clutch teeth extending from an outer surface of the clutch, wherein the plurality of clutch teeth are outwardly biased to be releasably engaged with the profile of the outer connector, wherein the plurality of clutch teeth are configured to permit the outer connector to rotate the inner connector when an operational torque is below a torque limit, and the plurality of clutch teeth are forced inward to disengage the profile of the outer connector and permit rotation of the outer connector relative to the inner connector when the operational torque exceeds the torque limit.

In certain embodiments, a method to tighten a connection is disclosed that comprises threadedly engaging a first connector with a second connector; rotating an outer connector of the first connector at an operational torque below a connection torque limit; and rotating an inner connector of the first connector via the rotation of the outer connector, wherein a clutch rotationally engages the inner connector and the outer connector.

The disclosed torque limiting connector incorporates a two-part connector with a clutch. The clutch can be disposed between the inner connector and the outer connector to limit torque to the inner connector. By limiting torque to the inner connector, overtightening of connectors can be prevented, preventing damage to connectors and simplifying removal.

The detailed description set forth below is intended as a description of various configurations of the subject technology and is not intended to represent the only configurations in which the subject technology may be practiced. Like components are labeled with identical element numbers for ease of understanding. Reference numbers may have letter suffixes appended to indicate separate instances of a common element while being referred to generically by the same number without a suffix letter.

While the following description is directed to the connection of medical fittings for the administration of medical fluid using the disclosed torque limiting connector, it is to be understood that this description is only an example of usage and does not limit the scope of the claims. Various aspects of the disclosed torque limiting connector may be used in any application where it is desirable to provide for the connection of various tubing and fittings without overtightening.

The disclosed torque limiting connector overcomes several challenges discovered with respect to certain conventional connectors. One challenge with certain conventional connectors is that threaded connectors may be easily overtightened if the engagement surfaces are wet, such as from a disinfectant. Further, clinicians may overtighten conventional connectors to prevent leaks. Because overtightened connectors may require increased (up to three times greater) disconnection force, necessitating the use of mechanical aids such as forceps or pliers, or the replacement of the connected catheter and/or tubing sets, the use of conventional connectors is undesirable.

Therefore, in accordance with the present disclosure, it is advantageous to provide a torque limiting connector as described herein that eliminates or substantially reduces potential overtightening of the connector. The disclosed torque limiting connector provides an intermediate clutch that permits tightening of the connector, while preventing overtightening of the connector.

An example of a torque limiting connector that prevents overtightening is now described.

<FIG> is a perspective view of a connector assembly <NUM>, in accordance with various aspects of the present disclosure. <FIG> is an elevation view of the connector assembly <NUM> of <FIG>, in accordance with various aspects of the present disclosure. With reference to <FIG> and <FIG>, the connector assembly <NUM> facilitates a fluid connection with a mating connector. In the depicted example, the inner connector <NUM> can be threaded to a mating connector at the upper end and/or the lower end. For example, the connector assembly <NUM> can be utilized with medical tubing.

To tighten the connector assembly <NUM> to a mating connector, the outer connector <NUM> can be twisted to tighten the threaded connections of the inner connector <NUM>. In some applications, a desired tightness or torque is specified for the connection between the connector assembly <NUM> and the mating connector. However, during use, clinicians may overtighten connections. For example, the disconnecting force for a connection may be higher after disinfecting the connectors. Mating connections may be disassembled or removed by twisting the connector assembly <NUM> in the opposite direction.

Advantageously, the connector assembly <NUM> prevents the inner connector <NUM> from being overtightened to a mating connector. During operation, until the desired torque is reached, rotation of the outer connector <NUM> rotates the inner connector <NUM>, tightening the mating connection therebetween.

However, after the desired torque is reached, a clutch mechanism prevents the outer connector <NUM> from further tightening the inner connector <NUM>. Therefore, after the desired torque is reached, the outer connector <NUM> may be rotated independently of the inner connector <NUM>.

In addition to preventing overtightening of the inner connector <NUM>, the connector assembly <NUM> can provide feedback or signals to the user that the desired mating torque has been reached. For example, upon rotation of the outer connector <NUM> after a desired torque is reached, the connector assembly <NUM> may provide an auditory or tactile signal or feedback (such as a "click").

<FIG> is an exploded perspective view of the connector assembly of <FIG>, in accordance with various aspects of the present disclosure. <FIG> is a cross-sectional view of the connector assembly of <FIG>, in accordance with various aspects of the present disclosure. With reference to <FIG> and <FIG>, a clutch <NUM> permits the connector assembly <NUM> to limit the amount of torque delivered to the inner connector <NUM> from the outer connector <NUM>.

In the depicted example, the clutch <NUM> is rotatably coupled with the inner connector <NUM> and releasably engaged with the outer connector <NUM>. Therefore, during operation, the clutch <NUM> allows the outer connector <NUM> to rotate the inner connector <NUM> until a desired maximum torque is achieved.

As shown, the clutch <NUM> may be disposed between the inner connector <NUM> and the outer connector <NUM>. In some embodiments, the clutch <NUM> is concentrically disposed about the inner connector <NUM>. For example, the clutch <NUM> can be disposed along the tapered outer surface <NUM> of the inner connector <NUM>. Optionally, the clutch <NUM> can be axially retained relative to the inner connector <NUM>. For example, the clutch <NUM> can be axially retained in a clutch groove <NUM> defined by an angled flange <NUM> formed on the tapered outer surface <NUM> of the inner connector <NUM>. In some embodiments, the outer connector <NUM> can include features to axially retain the clutch <NUM>. The angled flange <NUM> can have an angled surface to facilitate assembly of the clutch <NUM> onto the inner connector <NUM>.

In the depicted example, the clutch <NUM> can receive rotational torque from the outer connector <NUM>. Further, as illustrated, the clutch teeth <NUM> extend from an outer surface <NUM> of the clutch <NUM> to interface with an inner profile of the outer connector <NUM>. The interface of the clutch teeth <NUM> with the outer connector <NUM> allows for torque to be transferred to the clutch <NUM>.

As illustrated, the outer connector <NUM> is disposed about the inner connector <NUM> and the clutch <NUM>. Optionally, the outer connector <NUM> is concentrically disposed about the inner connector <NUM> and the clutch <NUM>. In some embodiments, the outer connector <NUM> is axially retained relative to the inner connector <NUM>. For example, the outer connector <NUM> can snap fit over the angled flange <NUM> of the inner connector <NUM> to axially retain the outer connector <NUM> relative to the inner connector <NUM>.

During operation, to transfer torque from the clutch <NUM> to the inner connector <NUM>, the clutch <NUM> is rotationally coupled with the inner connector <NUM> to permit the clutch <NUM> and the inner connector <NUM> to rotate together. In the depicted example, the clutch <NUM> transfers rotational torque to the inner connector <NUM> via dogs or features <NUM> formed on the inner surface of the clutch <NUM> that engage with the outer surface of the inner connector <NUM>. In some embodiments, the features <NUM> of the clutch <NUM> engage with the slots or channels <NUM> formed in the tapered outer surface <NUM> of the inner connector <NUM>. Therefore, during operation, torque from the outer connector <NUM> is transferred to the inner connector <NUM> via the clutch <NUM> to rotate the inner connector <NUM> relative to any mating connectors.

In the depicted example, the inner connector <NUM> includes an upper threaded portion <NUM> and a lower threaded portion <NUM>. By rotating the inner connector <NUM>, the upper threaded portion <NUM> and/or the lower threaded portion <NUM> can be tightened. For example, the threaded surface <NUM> of the upper threaded portion <NUM> can be tightened into a mating connector at a desired torque or until the upper threaded portion <NUM> bottoms out against the mating connector. Similarly, the lower threaded portion <NUM> can be tightened into a mating connector at a desired torque or until the lower threaded portion <NUM> bottoms out against the mating connector. As previously described, the outer connector <NUM> can rotate the inner connector <NUM> until the predetermined maximum torque is achieved.

During operation, after the maximum torque is achieved, the clutch teeth <NUM> can disengage from the outer connector <NUM>, permitting the outer connector <NUM> to spin without tightening the inner connector <NUM>. In some embodiments, the number of clutch teeth <NUM> in engagement with the outer connector <NUM> can determine the maximum torque that can be imparted from the outer connector <NUM> to the inner connector <NUM> prior to disengaging the outer connector <NUM>. For example, the clutch <NUM> can include more clutch teeth <NUM> to allow the outer connector <NUM> to impart more torque to the inner connector <NUM>, while in some embodiments, the clutch <NUM> can include fewer clutch teeth <NUM> to allow the outer connector <NUM> to impart less torque to the inner connector <NUM>. By way of example, the clutch <NUM> can include one clutch tooth <NUM>, three clutch teeth <NUM>, five clutch teeth <NUM>, or any other suitable number of clutch teeth <NUM>.

Similarly, the clutch <NUM> can permit the outer connector <NUM> to loosen the inner connector <NUM> from any mating connectors. The clutch <NUM> and the outer connector <NUM> may interface to limit loosening torque.

<FIG> is a bottom view of the connector assembly of <FIG>, in accordance with various aspects of the present disclosure. <FIG> is a detail view of the connector assembly of <FIG>, in accordance with various aspects of the present disclosure. With reference to <FIG>, clutch teeth <NUM> releasably engage against the connector profile <NUM> of the outer connector <NUM> to receive or transfer torque from the outer connector <NUM>.

During operation, the outer connector <NUM> is rotated, thereby rotating the connector profile <NUM>. The rotation of the connector profile <NUM> transmits torque to the clutch teeth <NUM> and thereby to the inner connector <NUM>. The outer connector <NUM> can continue to provide torque to or otherwise rotate the inner connector <NUM> as long as the clutch teeth <NUM> remain in engagement with the connector profile <NUM>.

In the depicted example, the clutch teeth <NUM> extend radially outward toward the connector profile <NUM>. As shown, the clutch teeth <NUM> are outwardly biased to maintain engagement with the connector profile <NUM>. In some embodiments, the clutch teeth <NUM> are resiliently or elastically biased toward the connector profile <NUM>. In some applications, the biasing force of the clutch teeth <NUM> can be modified by selecting the material, thickness, depth, and other characteristics of the clutch teeth <NUM> and the clutch <NUM>. Optionally, the angle or geometry of the bend <NUM> of the clutch teeth <NUM> can be modified to adjust the biasing force of the clutch teeth.

As illustrated, the connector profile <NUM> includes a plurality of engagement features <NUM> that can transfer rotational force from the outer connector <NUM> to the engaged clutch teeth <NUM> in a tangent direction to provide torque to the inner connector <NUM> and/or force in a radial direction to urge the clutch teeth <NUM> inwardly and out of engagement with the connector profile <NUM>. For example, an engagement feature <NUM> that transfers rotational force from the outer connector <NUM> to a clutch tooth <NUM> in a primarily tangential direction (the engagement feature <NUM> extending primarily normal to the outer connector <NUM>) will transfer proportionally more torque than inward radial force to a clutch tooth <NUM> compared to an engagement feature <NUM> that transfers rotational force from the outer connector <NUM> to the clutch tooth <NUM> in a primarily radial direction (the engagement feature <NUM> extending primarily tangent to the outer connector <NUM>), which may transfer less torque and more inward radial force to the clutch tooth <NUM>. In some embodiments, the engagement features <NUM> can include a combination tangent and radial components to control the proportion of torque that is transferred from the outer connector <NUM> to the inner connector <NUM> and the amount of inward radial force that is applied to the clutch teeth <NUM>.

During operation, when the inward radial force imparted on the clutch teeth <NUM> by the engagement features <NUM> overcomes the outward biasing force maintaining the clutch teeth <NUM> in engagement with the connector profile <NUM>, the clutch teeth <NUM> are disengaged from the outer connector <NUM> and allow the outer connector <NUM> to rotate relative to the inner connector <NUM>, limiting torque transferred to the inner connector <NUM>. Optionally, the disengaged clutch teeth <NUM> may provide an audible and/or tactile signal to the user.

By modifying geometric and material properties of the engagement features <NUM> and the clutch teeth <NUM>, the amount of torque that is applied to the inner connector <NUM> prior to disengaging the clutch teeth <NUM> can be controlled. For example, the relative angle of the engagement features <NUM> can be adjusted to have a higher operational torque limit or a lower operational torque limit.

In some embodiments, the connector assembly <NUM> can provide different torque limits for tightening and loosening. For example, the connector assembly <NUM> may provide a lower torque limit for tightening the connector assembly <NUM> and a higher torque limit for loosening the connector assembly <NUM>.

In the depicted example, the engagement features <NUM> may be asymmetric. As shown, the profile on the leading side <NUM> of the engagement feature <NUM> may differ from the profile on the trailing side <NUM> of the engagement feature <NUM>. In some embodiments, the leading side <NUM> may allow for less torque to be imparted in the tightening direction (the leading side <NUM> extending relatively tangent to the outer connector <NUM>) while the trailing side <NUM> may allow for greater torque to be imparted in the loosening direction (the trailing side <NUM> extending relatively normal to the outer connector <NUM>).

Optionally, the engagement features <NUM> can include varying geometric features. For example, the engagement features <NUM> can be rounded or angular to facilitate or inhibit the clutch teeth <NUM> to disengaging from the connector profile <NUM>. Similarly, complimentary geometric features of the tooth profile <NUM> of the clutch tooth <NUM> can be altered to engage with the engagement features <NUM>.

Terms such as "top," "bottom," "front," "rear" and the like if used in this disclosure should be understood as referring to an arbitrary frame of reference, rather than to the ordinary gravitational frame of reference. Thus, a top surface, a bottom surface, a front surface, and a rear surface may extend upwardly, downwardly, diagonally, or horizontally in a gravitational frame of reference.

Claim 1:
A torque limiting connector (<NUM>), comprising:
an outer connector (<NUM>) comprising a profile (<NUM>) disposed on an inner surface of the outer connector;
an inner connector (<NUM>) disposed within the outer connector, the inner connector comprising: an upper threaded portion (<NUM>, <NUM>), a lower threaded portion (<NUM>), a tapered outer surface (<NUM>), and channels (<NUM>) formed along the tapered outer surface; and
a clutch (<NUM>) comprising a plurality of clutch teeth (<NUM>) extending from an outer surface (<NUM>) of the clutch, and coupling features (<NUM>) formed on an inner surface of the clutch,
wherein the clutch (<NUM>) is disposed around and rotationally coupled to the inner connector (<NUM>) such that the coupling features (<NUM>) engage with the channels (<NUM>) to rotationally couple the clutch (<NUM>) and the inner connector (<NUM>), and the plurality of clutch teeth (<NUM>) are outwardly biased to be releasably engaged with the profile of the outer connector (<NUM>),
wherein the plurality of clutch teeth (<NUM>) are configured to transfer an operational torque from the outer connector (<NUM>) to the inner connector (<NUM>) when the operational torque is below a torque limit, and the plurality of clutch teeth are forced inward to disengage the profile of the outer connector and prevent transfer of the operational torque when the operational torque exceeds the torque limit.