Patent Description:
Traditional pinch clamp designs suffer from various drawbacks. For example, due to the molding process, pinch clamps typically have sharp edges that may cause patient discomfort. The molding process also causes the pinch clamps to be relatively bulky. Many pinch clamp designs also allow the two arms to move laterally when in the closed position leading to unintended disengagement of the pinch clamp. Even when lateral disengagement features are incorporated into these designs, asymmetry in the features oftentimes leads to failure in one direction.

Many pinch clamp designs also enable over-engagement which may result in rebound. <FIG> illustrate an example of how rebound may occur when a pinch clamp <NUM> is over-engaged. Pinch clamp <NUM> includes an upper arm <NUM> that is connected to a lower arm <NUM> via a living hinge <NUM>. A terminal portion <NUM> (where "terminal" represents that terminal portion <NUM> is towards the patient or distal end of tubing <NUM> relative to living hinge <NUM>) extends upwardly from lower arm <NUM> opposite living hinge <NUM>. An engaging structure <NUM> is formed at the upper end of terminal portion <NUM>. Engaging structure <NUM> forms an engaging surface <NUM> that is oriented downwardly to enable the leading end <NUM> of upper arm <NUM> to be maintained below engaging surface <NUM> to thereby engage pinch clamp <NUM>. In this engaged position, lower clamping surface <NUM> and upper clamping surface <NUM> are positioned with sufficient proximity to obstruct tubing <NUM> that extends through pinch clamp <NUM>.

<FIG> illustrates pinch clamp <NUM> when in the engaged position. To move pinch clamp <NUM> into this engaged position, the clinician will typically squeeze upper and lower arms <NUM>, <NUM> until leading end <NUM> of upper arm <NUM> drops below engaging surface <NUM>. At that point, the biased terminal portion <NUM> will maintain leading end <NUM> beneath engaging surface <NUM>. Difficulties arise, however, due to the ability of upper arm <NUM> to travel downwardly beyond what is necessary to reach the engaged position. For example, <FIG> illustrates that upper arm <NUM> has been forced downward so that leading end <NUM> has traveled substantially beyond engaging surface 141a. As a result, upper clamping surface <NUM> has contacted lower clamping surface <NUM> and traveled in a forward direction (i.e., towards terminal end <NUM>) relative to lower clamping surface <NUM>.

This forward movement of upper clamping surface <NUM> relative to lower clamping surface <NUM> results in "positive displacement" of the fluid within tubing <NUM> as represented by the arrow in <FIG>. In other words, the over-engagement of pinch clamp <NUM> will cause fluid within tubing <NUM> to flow into or at least towards the patient. Positive displacement is generally desirable. However, in this scenario, because the positive displacement is a result of over-engagement, a rebound will occur as represented in <FIG>. In <FIG>, it is assumed that the clinician is no longer squeezing pinch clamp <NUM> and therefore, upper arm <NUM> has pivoted upwardly back to the engaged position (i.e., until leading end <NUM> contacts engaging surface 141a). This upward movement of upper arm <NUM> relative to lower arm <NUM> will cause upper clamping surface <NUM> to also travel in an upward and somewhat backward direction. This upward and backward movement increases the internal volume of tubing <NUM> downstream from the "pinch point. " (i.e., the point where lower clamping surface <NUM> and upper clamping surface <NUM> occlude tubing <NUM>). As a result, fluid - likely including blood - will be sucked into the catheter of other device to which tubing <NUM> is coupled. The term rebound represents this transition from the over-engaged position depicted in <FIG> to the engaged position depicted in <FIG>.

The reflux that results from a pinch clamp rebound creates a number of problems. For example, the reflux of blood can increase the risk of occlusion (e.g., due to an intraluminal thrombus within the catheter) which may prevent fluids from being infused through the catheter or prevent blood from being withdrawn. Even if occlusion does not occur, the reflux can increase the risk of infection.

<CIT> discloses a pinch clamp device showing the combination of features of the preamble of claim <NUM>.

<CIT> discloses a clamp for clamping flexible tubing.

<CIT> discloses a blood bag system including a clamp installed in a flexible first tube.

<CIT> discloses a clamp for controlling the flow of liquid through a fluid circuit.

The subject matter of the invention is defined by independent claim <NUM>.

The present disclosure relates generally to pinch clamps that are designed to provide positive displacement while also preventing rebound. As a result, the design of these pinch clamps minimizes the occurrence of reflux. In addition to preventing rebound, the design of the pinch clamps can prevent lateral disengagement, minimize the force required for engagement and enhance patient comfort.

To prevent rebound while providing positive displacement, the upper and lower clamping surfaces may be configured to form a pinch profile along which the tubing is compressed with the pinch point being formed at the distal end of the pinch profile. To further prevent rebound, the lower arm of the pinch clamp can include blocking ribs that interface with the upper clamping surface to prevent distal travelling of the pinch point even if the upper arm is forced into an over-engaged position.

The present disclosure relates to a pinch clamp that includes an upper arm having a proximal end and a distal end and a lower arm having a proximal end and a distal end where the proximal end of the lower arm is coupled to the proximal end of the upper arm via a hinge. The pinch clamp also includes a terminal end that extends upwardly from the distal end of the lower arm. The terminal end includes an engaging structure that forms an engaging surface that interfaces with the distal end of the upper arm to retain the pinch clamp in an engaged position. An upper clamping surface is formed on the upper arm and has a proximal portion and a distal portion. Also, a lower clamping surface is formed on the lower arm and has a proximal portion and a distal portion. When the pinch clamp is in the engaged position, a distance between the distal portion of the upper clamping surface and the distal portion of the lower clamping surface is less than a distance between the proximal portion of the upper clamping surface and the proximal portion of the lower clamping surface.

The present disclosure further relates to a pinch clamp that includes an upper arm having a proximal end and a distal end and a lower arm having a proximal end and a distal end where the proximal end of the lower arm is coupled to the proximal end of the upper arm via a hinge. The pinch clamp also includes a terminal end that extends upwardly from the distal end of the lower arm. The terminal end includes an engaging structure that forms an engaging surface that interfaces with the distal end of the upper arm to retain the pinch clamp in an engaged position. An upper clamping surface is formed on the upper arm and has a proximal portion and a distal portion. Also, a lower clamping surface is formed on the lower arm and has a proximal portion and a distal portion. The pinch clamp further includes blocking ribs that are positioned on opposing sides of the lower arm and extend distally from the distal portion of the lower clamping surface.

Moreover, the present disclosure relates to a pinch clamp that includes an upper arm having a proximal end and a distal end and a lower arm having a proximal end and a distal end where the proximal end of the lower arm is coupled to the proximal end of the upper arm via a hinge. The pinch clamp also includes a terminal end that extends upwardly from the distal end of the lower arm. The terminal end includes an engaging structure that forms an engaging surface that interfaces with the distal end of the upper arm to retain the pinch clamp in an engaged position. An upper clamping surface is formed on the upper arm and has a flat proximal portion and a distal portion that protrudes downwardly from the flat proximal portion. A lower clamping surface is formed on the lower arm and is flat.

It is to be understood that both the foregoing general description and the following detailed description are exemplary and explanatory and are not restrictive of the invention, as claimed. It should be understood that the various embodiments are not limited to the arrangements and instrumentality shown in the drawings.

Pinch clamps that are configured in accordance with the present invention can provide positive displacement while also preventing rebound to thereby minimize the occurrence of reflux. By structuring the upper and lower clamping surfaces to provide a pinch profile, as opposed to a single pinch point, the pinch clamps of the present invention can cause positive displacement. Additionally, the upper and lower clamping surfaces can be configured to form the pinch point towards the distal end of the pinch profile. The positioning of the pinch point towards the distal end can minimize the likelihood of rebound if the pinch clamp is over-engaged. Alternatively or additionally, the pinch clamps can include blocking ribs that interface with the upper clamping surface to prevent distal travelling of the pinch point even if the upper arm is forced into an over-engaged position.

<FIG> provide various views of a pinch clamp <NUM> that is configured in accordance with embodiments of the present invention. Pinch clamp <NUM> includes an upper arm <NUM>, a lower arm <NUM>, a living hinge <NUM> that couples the proximal ends of upper and lower arms <NUM>, <NUM> and a terminal end <NUM> that extends upwardly from the distal end of lower arm <NUM>. Living hinge <NUM> and terminal end <NUM> form openings 230a and 240a respectively through which tubing (not shown) extends. An upper portion of terminal end <NUM> forms an engaging structure <NUM> having a downward facing engaging surface 241a. Upper arm <NUM> pivots relative to lower arm <NUM> to allow leading end <NUM> of upper arm <NUM> to be secured under engaging surface 241a to thereby maintain pinch clamp <NUM> in the engaged position. In some embodiments, leading end <NUM> may include a protruding portion <NUM> that extends outwardly from one side of upper arm <NUM>. To enhance grip, upper arm <NUM> and lower arm <NUM> may include a series of ridges <NUM> and <NUM> respectively that span the width of the respective arm.

To prevent lateral disengagement, lower arm <NUM> can include tabs <NUM> that extend upwardly from opposing sides of lower arm <NUM> to thereby form a gap between the tabs. Upper arm <NUM> can include a rib <NUM> that extends downwardly from the underside of upper arm <NUM> and that is configured to insert into the gap between tabs <NUM>. The interface between rib <NUM> and tabs <NUM> will prevent upper arm <NUM> from moving laterally relative to lower arm <NUM> while in the engaged position thereby preventing leading end <NUM> from becoming laterally disengaged from engaging surface 241a. As is best seen in <FIG>, rib <NUM> and tabs <NUM> can be positioned towards terminal end <NUM>. In addition to preventing lateral disengagement, tabs <NUM> also function to center the tubing between lower arm <NUM> and upper arm <NUM>. In other embodiments, pinch clamp <NUM> may not include rib <NUM> as is shown in <FIG>. In such embodiments, pinch clamp <NUM> can be disengaged by lateral movement but will still provide positive displacement and center the tubing.

As is best shown in <FIG>, pinch clamp <NUM> can be configured so that, when lower arm <NUM> is horizontal and pinch clamp <NUM> is in the disengaged position, upper arm <NUM> will be oriented at an upward angle. Also, as best shown in <FIG>, the outer edges <NUM> of upper arm <NUM> and lower arm <NUM> are rounded to eliminate sharp edges and thereby enhance patient comfort.

Upper arm <NUM> forms an upper clamping surface <NUM> that is positioned proximal to and extends downwardly beyond rib <NUM>. In some embodiments, including the embodiment depicted in <FIG>, upper clamping surface <NUM> includes a generally flat proximal portion 252b and a protruding distal portion 252a. In other embodiments, upper clamping surface <NUM> may not include protruding distal portion 252a such that upper clamping surface <NUM> is generally flat from its proximal end to its distal end. Lower arm <NUM> forms a lower clamping surface <NUM> that is generally flat. Blocking ribs <NUM> extend distally beyond a distal end of lower clamping surface <NUM> along opposing sides of lower arm <NUM>. A gap 253a is thereby formed between blocking ribs <NUM> distal to lower clamping surface <NUM>. In some embodiments, tabs <NUM> comprise a raised extension of blocking ribs <NUM>.

Upper clamping surface <NUM> and lower clamping surface <NUM> are both elongated to thereby create a pinch profile when pinch clamp <NUM> is in the engaged position. With reference to <FIG>, upper clamping surface <NUM> can be configured so that it is angled upwardly in a distal direction relative to lower clamping surface <NUM> when pinch clamp is in the disengaged position. Then, once pinch clamp <NUM> is transitioned into the engaged position, upper clamping surface <NUM> pivots into a downward orientation relative to lower clamping surface <NUM>. As part of this transition, proximal portion 252b will first contact and compress the tubing towards a proximal end of lower clamping surface <NUM>. This compression of the tubing will cause positive displacement. As pinch clamp <NUM> transitions fully into the engaged position and due to the downwardly angled orientation of upper clamping surface <NUM>, distal portion 252a will contact, compress and occlude the tubing (i.e., create the pinch point) towards a distal end of lower clamping surface <NUM>. Accordingly, the pinch profile consists of compression of the tubing towards the proximal end of clamping surfaces <NUM>/<NUM> and occlusion of the tubing at the distal end of clamping surfaces <NUM>/<NUM>.

The force required to occlude the tubing is minimized by providing protruding distal portion 252a. More specifically, protruding distal portion 252a minimizes the length of the tubing that is occluded thereby minimizing the squeezing force required to reach the engaged position. In contrast, if upper clamping surface <NUM> is flat, a greater length of tubing would be compressed and occluded thereby increasing the squeezing force required to reach the engaged position.

Again with reference to <FIG>, due to the positioning of blocking ribs <NUM>, if an over-engaging force is applied to pinch clamp <NUM>, upper clamping surface <NUM> will be blocked from travelling in a downward direction relative to lower clamping surface <NUM>. In other words, blocking ribs <NUM> will prevent the pinch point from travelling in a distal direction thereby preventing rebound once the over-engaging force is removed. The generally flat orientation of lower clamping surface <NUM> and blocking ribs <NUM> combined with the downwardly angled orientation of upper clamping surface <NUM> will also convert the over-engaging force on upper arm <NUM> into a pivoting force around distal portion 252a. This pivoting force will minimize the likelihood that upper clamping surface <NUM> will slide in a distal direction relative to lower clamping surface <NUM>.

<FIG> illustrates an alternate configuration of lower clamping surface <NUM> and upper clamping surface <NUM> that also provides a pinch profile. In this embodiment, upper clamping surface <NUM> includes a generally flat proximal portion 252b and a protruding distal portion 252a similar to what was described above. However, lower clamping surface <NUM> also includes a protruding distal portion 251b that generally aligns with distal portion 252a but that is elongated relative to distal portion 252a. In this configuration, the generally flat proximal portions of upper and lower clamping surfaces <NUM>/<NUM> will compress the tubing while distal portions 252a/251a will form the pinch point.

<FIG> illustrates another alternate configuration of lower clamping surface <NUM> and upper clamping surface <NUM> that also provides a pinch profile. In this embodiment, lower clamping surface <NUM> is not flat, but includes a protruding proximal portion 251b in addition to protruding distal portion 251a. Proximal portion 251b protrudes upwardly farther than distal portion 251a. Upper clamping surface <NUM> includes protruding distal portion 252a as well as a protruding proximal portion 252b. A recessed portion 252c is formed between distal portion 252a and proximal portion 252b and has a curved shape that corresponds to the curved shape of proximal portion 251b. Proximal portion 251b inserts into recessed portion 252c which in turn can prevent over-engagement of the pinch clamp.

As shown in <FIG>, when in the engaged position, a generally constant spacing is formed between proximal portion 251b and recessed portion 252c and between proximal portion 251b and proximal portion 252b. This constant spacing forms a channel in which the tubing will be compressed but not occluded. In contrast, in the engaged position, the spacing between distal portion 252a and distal portion 251a is less than the constant spacing between the other portions so that a pinch point is formed between distal portions 252a/251a.

In the embodiments shown in <FIG>, the elongated upper and lower clamping surfaces will provide positive displacement and will also prevent rebound. Rebound is prevented due to the pinch profile which positions the pinch point at the distal end of the clamping surfaces.

Claim 1:
A pinch clamp (<NUM>) comprising:
an upper arm (<NUM>) having a proximal end and a distal end;
a lower arm (<NUM>) having a proximal end and a distal end, wherein the proximal end of the lower arm is coupled to the proximal end of the upper arm via a hinge (<NUM>);
a terminal end (<NUM>) that extends upwardly from the distal end of the lower arm, the terminal end including an engaging structure (<NUM>) that forms an engaging surface (241a) that interfaces with the distal end of the upper arm to retain the pinch clamp in an engaged position; and
a lower clamping surface (<NUM>) formed on the lower arm, the lower clamping surface having a proximal portion and a distal portion,
characterized in that the pinch clamp comprises an upper clamping surface (<NUM>) formed on the upper arm, the upper clamping surface having a flat proximal portion (252b) and a distal portion (252a) that protrudes downwardly from the flat proximal portion, wherein
when the pinch clamp is in the engaged position, a distance between the distal portion of the upper clamping surface and the distal portion of the lower clamping surface is less than a distance between the proximal portion of the upper clamping surface and the proximal portion of the lower clamping surface such that the pinch clamp compresses tubing towards the proximal portions of the upper and the lower clamping surfaces and occludes the tubing at the distal portions of the upper and the lower clamping surfaces.