Lancing device and lancet

A lancing device and lancet are provided with depth-control, lancet ejection, and/or guidance mechanisms. The depth-control mechanism includes a dial rotationally mounted at a distal end of the housing of the lancing device, the dial being coupled to a linkage whereby rotation of the dial imparts translational movement to a stop surface of the linkage to limit the stroke of the lancet and thereby control lancing penetration depth. The ejection mechanism includes an ejector that is advanced into contact with a transversely flared flange of the lancet to discharge the lancet from the lancing device. The guidance mechanism includes an inner guidance housing for restricting out-of-axis movement of a lancet carrier.

TECHNICAL FIELD

The present invention relates generally to the field of medical devices, and more particularly to lancets and lancing devices for blood sampling and testing.

BACKGROUND OF THE INVENTION

Lancets and lancing devices are utilized for penetrating the skin of a human or animal subject at a lancing site to obtain a sample of blood or other body fluid for medical testing, as in blood-typing or blood-glucose testing. Known lancing devices commonly include a housing containing a drive mechanism, a charging mechanism for energizing the spring or other drive means of the drive mechanism, and a release mechanism for releasing the drive mechanism upon actuation. A lancet is typically propelled by the drive mechanism from a retracted position within the housing to an extended position wherein a sharp tip portion of the lancet projects from the housing to prick the subject's skin at a desired lancing site. A depth-control mechanism can optionally be provided to adjust the penetration depth of the lancet.

The lancet is typically a disposable component that is removably mounted into a receiver or lancet carrier portion of the drive mechanism of a lancing device. A used lancet typically is removed from the lancet carrier after sampling for disposal. An ejection mechanism can optionally be included for discharge of the used lancet from the lancing device. A new, sterile lancet is then replaced into the lancet carrier for further sampling. Lancets typically comprise a sharp metal tip in the form of a needle or blade. The needle or blade is typically embedded in a plastic body that has a size and shape configured for releasable engagement with the receiver or lancet carrier of a lancing device. The sharp tip of the lancet is commonly embedded in a removable plastic cap to maintain sterility and prevent inadvertent sticks prior to use. The endcap may be replaceable onto the lancet after use to re-cover the sharp lancet tip for safety and hygienic purposes.

It is to the provision of improved lancing devices and lancets that the present invention is primarily directed.

SUMMARY OF THE INVENTION

In example embodiments, the present invention provides an improved lancing device, an improved lancet, and a system including a lancing device with a proprietary or device-specific lancet. Example embodiments include an improved depth-adjust mechanism for selectively varying the penetration depth of the lancet, an improved lancet ejector system using a protrusion or surface of the lancet to eject a used lancet from the lancing device, and/or an improved guidance system for guiding the path of travel of the lancet along its lancing stroke.

In one aspect, the invention relates to a lancing device including a housing, a lancet carrier mounted within the housing for movement between a retracted position and a lancing position, and a depth-control mechanism. The depth-control mechanism includes a dial rotationally mounted relative to the housing, and a linkage mechanism coupled to the dial and having a stop member for limiting travel of the lancet carrier at the lancing position.

In another aspect, the invention relates to a lancing system including a lancet and a lancing device for receiving and discharging said lancet. The lancet includes a lancet body, a sharp lancing tip projecting axially from a proximal end of the lancet body, and a flared flange projecting transversely from the lancet body. The lancing device includes an ejection mechanism having an abutment member for contacting the flared flange of the lancet and ejecting the lancet from the lancing device.

In another aspect, the invention relates to a lancet including a lancet body, a sharp lancing tip projecting axially from a proximal end of the lancet body, and a flared flange projecting transversely from the lancet body.

In still another aspect, the invention relates to a lancing system including a lancet and a lancing device for receiving and discharging said lancet. The lancet includes a lancet body, a sharp lancing tip projecting axially from a proximal end of the lancet body, and a recess in the lancet body. The lancing device includes an ejection mechanism having a protrusion for engaging the recess in the lancet body and pushing on the lancet body to eject the lancet from the lancing device.

In another aspect, the invention relates to a lancet including a lancet body, a sharp lancing tip projecting axially from a proximal end of the lancet body, and a recess in a side of the lancet body for engagement with an ejector of a lancing device

In another aspect, the invention relates to a lancing device including a housing, a lancet carrier mounted within the housing for movement between a retracted position and a lancing position, and a depth-control mechanism. The depth-control mechanism includes a dial rotationally mounted relative to the housing, and a linkage coupled to the dial and having a contact face for limiting travel of the lancet carrier at the lancing position.

In another aspect, the invention relates to a lancing system including a lancet and a lancing device for receiving and discharging the lancet. The lancet includes a lancet body, a sharp lancing tip projecting axially from a proximal end of the lancet body, and a flared flange projecting transversely from the lancet body. The lancing device includes an ejection mechanism comprising an abutment face or protrusion for contacting the flared flange of the lancet and ejecting the lancet from the lancing device.

In still another aspect, the invention relates to a lancing system including a lancet and a lancing device for receiving and discharging the lancet. The lancet includes a lancet body, a sharp lancing tip projecting axially from a proximal end of the lancet body, and a slot, pocket, or similar cavity in the side of the lancet body. The lancing device includes an ejection mechanism comprising an abutment face (protrusion) for contacting the slot, pocket, or similar cavity in the side of the lancet body and ejecting the lancet from the lancing device.

In another aspect, the invention relates to a lancing device including an outer housing, a lancet carrier translationally movable within the housing, and an inner guidance housing mounted within the outer housing for constraining the lancet carrier to axial movement along a linear lancing stroke.

In another aspect, the invention relates to a lancet including a lancet body, a sharp lancing tip projecting axially from a proximal end of the lancet body, and a flared flange projecting transversely from the lancet body.

In still another aspect, the invention relates to a lancet includes a lancet body, a sharp lancing tip projecting axially from a proximal end of the lancet body, and a slot, pocket, or similar cavity in the side of the lancet body for interaction with an ejector.

DETAILED DESCRIPTION OF EXAMPLE EMBODIMENTS

With reference now to the drawing figures, wherein like reference numbers represent corresponding parts throughout the several views,FIGS. 1-6show a lancing system comprising a lancing device10and lancet12according to example forms of the invention. The lancet12is optionally configured in size and shape to be specific or proprietary to the lancing device of the invention, whereby the lancing device and lancet comprise a complementary system. While the lancing device and lancet can take a variety of forms, in the embodiment ofFIG. 1the lancing device comprises a housing20formed of upper and lower half-shells22a,22b, and optionally a removable proximal endcap24with a contact face having a lancet opening26therein for allowing passage of the sharp lancet tip during lancing.

FIGS. 2-6show internal components of a lancing device10according to a first example embodiment of the invention with the outer housing removed. The lancing device10comprises a drive mechanism comprising a lancet carrier30, a drive spring40for propelling the lancet carrier from a retracted position within the housing to an extended or lancing position with the sharp lancet tip projecting out of the housing, and a return spring42for returning the lancet carrier to a neutral position within the housing after use. The lancing device further comprises a charging mechanism for retracting the lancet carrier from the neutral position to the retracted position and compressing the drive spring; and an activation mechanism for releasing the lancet carrier from the retracted position to traverse the lancing stroke from the retracted position, through the lancing position, and back to the neutral position. The lancing device optionally further comprises one or more of a depth-control mechanism, an ejector mechanism, and/or a guidance mechanism, and/or any combination thereof. These mechanisms or subsystems will be described in greater detail below.

The depth of puncture provided by the lancing device may be adjusted so that the lancing process generates a sample of the necessary amount of blood for a successful blood glucose reading or other procedure while reducing, minimizing or eliminating undue pain to the subject.FIGS. 2-6show a first example embodiment of a depth-control mechanism according to the present invention. The depth-control mechanism comprises a depth-adjust dial60having a manipulation surface that the patient rotates to easily change the depth of puncture. In example forms, the dial rotates in a horizontal plane along the medial axis of the device housing, mounted between the upper and lower half-shells22a,22b. In alternate embodiments, the orientation and location of the depth-adjust dial can vary. The depth-control mechanism further comprises a stop member which acts as a limit of travel for the drive mechanism of the lancing device. In the depicted embodiment, the dial is mounted at the distal or rearward end of the housing and rotates about an axis of rotation that is generally perpendicular to the path of travel of the lancet along its lancing stroke. The stop member acts on a transverse protrusion or other surface of the lancet holder or on a protrusion attached to the lancet holder as the lancet holder moves through its lancing stroke, to arrest the forward motion of the lancet holder and limit the travel of the lancet thereby defining the proximal or forward extent of travel of the lancet tip in its fully extended position. By turning the dial60, the axial position of the stop member is changed thereby adjusting the point of contact of the lancet holder with the stop member relative to the outer housing, and in this manner the depth of penetration of the lancet is adjusted.

In example embodiments, the depth dial60is partially shielded within the device housing to improve the safety and user comfort delivered by the device by avoiding or reducing the incidence of unintentional depth adjustment that could cause unnecessary penetration depth. The rear end of the housing optionally is radiused to generally match the profile of the dial60with only the outer periphery of the dial projecting beyond the rearward end of the housing. The dial60preferably comprises numerical or other indicia visible on a portion of the dial from external of the rear end of the housing or through an opening or cutout portion of the housing20proximal its rear end, indicating the depth setting to the user. The mechanism of the depth dial preferably provides a smooth transition between depth settings and a clear indication of the depth setting, for example through a cutout on the housing20. A resilient finger or segment of the dial60interacts with detents or other indexing features of the housing to provide tactile feedback to the user of the depth settings, and to retain the depth-adjust mechanism in a set position. The dial60optionally has a scalloped, stepped, ridged or knurled edge for ease of adjustment.

The depth-control mechanism comprises a first link70and a second link72. The first link70has a distal end pivotally coupled to an eccentric pin62projecting from the depth-adjust dial60, and a proximal end pivotally connected by a hinge pin coupling to the distal end of the second link72. The proximal end of the second link72comprises a contact face or stop74for limiting the stroke of travel of the lancet carrier30. Rotation of the dial60causes translation of the two-part linkage70,72in the axial direction, and thereby adjusts the linear positioning of the stop74. A larger diameter dial60with a smaller eccentric offset of the pin62from the center or axis of rotation of the dial can be used to adjust the depth in small increments with larger rotational increments of the dial for ease of use by users with reduced manual dexterity. Optionally, the dial60moves through one or more indexed positional settings or through a continuous adjustment range, allowing the user to have an improved tactile feel between depth settings. Provision of one or both links70,72and/or stop surface74formed for example of a substantially rigid but resilient material optionally acts as a vibration reducer, decreasing the transfer of energy or impact sensed by the user upon contact of the lancet carrier with the stop.

In example embodiments, the depth dial60rotates through a range of motion of at least about 45-90 degrees to about 270 degrees, for example about 180 degrees. An arcuate flange on the lower face of the dial60optionally rotates within a corresponding arcuate track or channel in the lower housing half shell22b, or an axle extending from the dial rotates within a corresponding sleeve, bushing or bearing of the housing. The second link72is optionally generally T-shaped in profile, having a transversely extending rib forming the contact face74at its proximal end for limiting the stroke of the lancet carrier. One or both of the links70,72optionally include guidance features which engage the lancing device housing or other fixed part of the lancing device and control the motion of the two-part linkage in response to rotation of the depth dial. For example, the hinge pin connecting the links70,72and/or a finger or fin projecting from the second link72optionally rides in a track in the lower housing shell to maintain axial alignment of the second link, preventing pivotal movement and constraining the second link to axial translation in response to rotation of the dial. Rotation of the dial selectively varies the position of the contact face74, which defines the limit of motion of the lancet carrier30, thereby adjusting the depth of penetration of the lancet at the lancing site.

The lancet carrier30or other portion of the drive mechanism includes a contact element for abutment with the contact face74of the stop bar to limit the travel of the lancet carrier and thereby control the penetration depth. In the depicted embodiment, the lancet carrier30comprises a distal extension arm with an end having a contact element with a projection or finger32mounted thereon. The projection or finger32extends downwardly to contact the upwardly directed contact face74of the stop bar as the lancet carrier30traverses the forward portion of its lancing stroke. The contact element optionally takes the form of a sleeve held on the split distal end of the lancet carrier by one or more resilient barbs to retain the return spring42in place on the distal extension arm of the lancet carrier.

As the dial60is rotated, the axial distance that the linkage70,72moves is determined by how far the eccentric pin62is offset from the center of rotation of the dial60and the angle through which the dial is moved. Additionally, the distal end of the first link70moves transversely due to rotation of the dial to which it is coupled causing pivotal movement of the stop bar. Thus, there are two components of the movement of the first link70: an axial translational component along the long axis of the link70, and a transverse component perpendicular to the long axis of the link70. In the depicted embodiment, movement along the long axis of the stop bar70provides the majority of the depth adjustment. Specifically, for a dial rotation of 180 degrees, the bar70moves an axial distance about equal to twice the radial displacement or offset of the eccentric pin62from the center of rotation of the dial. For 90 degree rotation of the dial, the stop bar70moves (along the axis of interest) a distance about equal to the radial displacement or offset of the eccentric pin62from the center of rotation of the dial. The movement in the direction perpendicular to the long axis of the stop bar is converted to a pivotal toggling movement of the link70.

FIGS. 8A,8B and8C show a lancing device10′, generally as described above, and having another embodiment of a depth control mechanism comprising a “rack and pinion” type gear mechanism to vary the position of the contact face74′ of a connector link70′. The dial60′ includes a toothed spur gear or pinion62′ projecting from its center, in engagement with a rack76of like gear pitch. The link70′ is constrained to translate in only the direction along its long axis, eliminating its ability to rotate. An additional embodiment not illustrated in the figures replaces the rack and pinion gear with a take up reel on the dial and a push/pull cable connected to the depth stop.

Any number of angular positions of the dial can be converted into discrete movements of the depth stop74,74′ through the addition of indexing detents acting on either the dial or the linkage connecting the dial to the stop. Also, while the depicted embodiments show the depth stop acting on only one side of the lancet carrier or firing mechanism, the provision of a linkage which can act on two or more sides of the lancet carrier or firing mechanism is within the scope of the invention. And while the depicted embodiments show a configuration for controlling depth by limiting the lancing stroke by contact with the back end of the lancet carrier or firing mechanism, the depth control mechanism of the present invention also includes embodiments that limit the lancing stroke by contact with any point of the lancet carrier or firing mechanism from the rear up to and including the front where the lancet is engaged.

Ejector Mechanism

FIGS. 2,3,5A and5B show an example embodiment of a lancet ejection mechanism100for removal of a lancet12from the lancet carrier30. The lancet12of the lancing system of the present invention is optionally a low-mass proprietary lancet. Because there is less mass being driven during the activation of the device, the lancet may be propelled in and out of the subject's skin faster and with less vibration. Although the present invention is not bound to or limited by theory, faster puncture with a lower mass lancet is believed to reduce pain levels experienced by the subject. But the low-mass lancet generally has a smaller surface area and therefore may be more difficult to handle. Because of the very small size of the lancet12, a large endcap, and/or a collar or flange14having an expanded or flared transverse dimension is provided at the proximal end of the lancet body for easier manipulation and improved handling.

The limited surface area of the lancet's rear face also may not provide a sufficient contact surface for use with a rear ejection mechanism. Accordingly, the ejection mechanism of the present invention ejects a lancet by pushing on the lancet's flared collar14to force it out of the lancet carrier. In alternate forms, the system of the present invention comprises a lancet with a flange or other protrusion projecting outwardly from a location other than at the rear of the lancet and an ejector on the lancing device which pushes on this protrusion. Alternately, the lancet has a slot, pocket, or hole in the body and the ejector has a protrusion or other surface which engages this hole and pushes on the lancet to eject the lancet from the lancing device.

The ejection mechanism100comprises an ejector arm110slidably mounted between the lancet carrier30and a release button sleeve120. The ejector arm110includes an ejection actuator112providing a user interface for the user to manually operate the mechanism, and an abutment flange114for contacting the flared collar14or other contact surface of the lancet12to push the lancet out of engagement with the lancet carrier30. A notch or opening122in the lower face of the release button sleeve120engages a cooperating catch or projection33of the lancet carrier30to limit the forward movement of the lancet carrier as the lancet is ejected, and leaf springs124or other biasing means bias the sleeve120upward and into engagement with the lancet carrier unless the release button is pressed downwardly to activate the lancing device. A protrusion116on the ejector arm interferes with a cooperating protrusion on the housing endcap to prevent operation of the ejection mechanism unless the endcap is removed.

FIGS. 10A,10B and10C show an alternate ejection mechanism embodiment200comprising a lancet212having a recess214such as a slot, pocket, or hole in the lancet body, for example extending along a portion of the side of the lancet body. The ejector220has a protrusion222or other surface which extends through a corresponding slot232in the lancet carrier230and engages the recess214of the lancet212and pushes on the lancet to eject the lancet from the lancing device.

Guidance Mechanism

The guidance mechanism150of the present invention is shown in example form inFIGS. 2 and 7. While the present invention is not bound to or limited by theory, it is believed that in general, all else being equal, the smaller the side-to-side movement of the lancet needle (movement of the lancet tip transverse to the lengthwise axis of the lancet needle as it moves along the lancing stroke) during the lancing stroke and in particular as the lancet tip is penetrating the subject's skin at the lancing site, the lower the pain level experienced by the subject. Thus, the guidance mechanism of the present invention is configured to constrain the lancet to a relatively straight linear stroke or path of travel.

Minimizing the number of parts involved in the guidance mechanism advantageously reduces tolerance stacking and play between parts, making it easier to tightly control/limit the side-to-side movement of the lancet holder as it travels forward. Accordingly, the guidance mechanism150of the present invention consists of only a single fixed inner guidance housing160and a single moving member, namely the lancet carrier30. The inner guidance member160generally comprises a hollow sleeve having an internal channel with a shape and dimensions configured to generally match one or more outer surfaces or profile elements of the lancet carrier30, and thereby allow freely sliding movement of the lancet carrier along the lancing axis A, but minimize out-of-axis movement in any direction.

In example forms, the inner guidance housing160comprises a slot defined between a pair of spaced vertical struts162, and the lancet carrier30comprises an elongate rib35having a profile matching the slot with a close running fit. Additionally or alternatively, the lancet carrier30comprises a flange having an outer profile generally matching the inner profile of the channel of the inner guidance housing160with a close running fit. The inner guidance housing160and/or one or more components affixed thereto is/are engaged within the outer housing20at one or more points of contact to prevent relative play therebetween. In this manner, the inner guidance housing160and the drive mechanism constitute a drive chassis that can be mated to different outer housing configurations.

Charging and Activation

FIGS. 6A,6B and6C show a sequence of operation and method of use of the lancing system according to an example form of the invention.FIG. 6Ashows the inner mechanism of the lancing device10in a rest or neutral position. The drive spring40and return spring60are uncompressed (or relatively uncompressed) and in equilibrium. The catch33of the lancet carrier is engaged in the opening122in the lower face of the release button sleeve120to prevent the lancet carrier from moving substantially forward when a lancet is ejected or installed into the receiver of the lancet carrier.

FIG. 6Bshows the lancing device in a charging position. The user slides the charging actuator180rearward, compressing the drive spring40between a retention flange on the lancet carrier and the guidance housing. The inclined rear face of the catch33of the lancet carrier30presses the release button121and release button sleeve120downward against the bias of leaf springs124. As the forward catch surface of the catch33clears the rear edge of the release button sleeve120, the leaf springs pop the sleeve and release button back up to retain the lancet carrier30in the charged or cocked position.

FIG. 6Cshows the lancing device in a firing or activated position. The user places the lancet opening26of the endcap against the skin at the intended lancing site and presses the release button121, which moves the release button sleeve120downward against the bias of the leaf springs124, releasing the catch33of the lancet carrier from the release button sleeve and allows the drive spring to extend and propel the lancet carrier and lancet forward through the lancing stroke to penetrate the subject's skin at the lancing site. The return spring42then retracts the lancet tip to a shielded position back within the housing, returning to the rest or neutral state.

Lancet

FIG. 9shows a lancet12according to an example form of the invention. The lancet includes a lancet body202, a sharp lancet needle or blade204having a tip projecting from a proximal end of the lancet body, and a detachable endcap (unshown) having a distal end initially attached to the proximal end of the lancet body and having the tip of the lancet embedded therein Optionally, the lancet body202is configured to be proprietary or device-specific, wherein only a specified lancet design will engage within a particular lancing device type. For example, the lancet and the receiver of the lancet device can comprise correspondingly shaped cross-sectional profiles configured to provide a frictional engagement therebetween. In the depicted embodiment, the cross-sectional profiles are generally elliptical as seen best inFIGS. 7 and 9, but in alternate embodiments can comprise triangular, polygonal, or other regular or irregular profiles. Alternatively the lancet body may be of standard or universal format.