ASSEMBLIES FOR RELEASABLY SECURING A CASSETTE LID TO A CASSETTE BASE

Abstract

Exemplary embodiments provide locking mechanisms allowing the lid of a cassette assembly to be locked to a base of the cassette assembly. Some embodiments provide hinged locks or clips that flex or bend, allowing a lip on the lid to be secured under a protrusion on the base (or vice versa). In some embodiments, a secondary hinge allows the lid to be released. Some embodiments allow the lid to be secured through either of a pushing or twisting action, while others involve only pushing or only twisting.

Claims

1. A system comprising: a cassette lid comprising a number n of cassette lid engagement locations; and a cassette base comprising n cassette base engagement locations, the cassette base engagement locations sized and shaped to interact with the cassette lid engagement locations so that the cassette base engagement locations receive the cassette lid engagement locations and lock the cassette base to the cassette lid through a twisting action.

2. The system of claim 1, wherein the cassette lid comprises an outer circumferential lip, and the cassette lid engagement locations are projections extending in radially outward direction beyond an end of the outer circumferential lip.

3. The system of claim 1, wherein the cassette base comprises a circumferential track, and the cassette base engagement locations each comprise a well recessed or cut out from into the circumferential track.

4. The system of claim 3, wherein each well is sized to receive a corresponding cassette lid engagement location so that the cassette lid engagement locations drop below a level of the circumferential track during an installation operation.

5. The system of claim 3, wherein each well further comprises a lead-in ramp configured to guide a respective cassette lid engagement location into the well.

6. The system of claim 1, wherein each cassette base engagement location comprises a stop, the stop comprising a top surface having an angled or rounded side and a bottom surface.

7. The system of claim 6, wherein the bottom surface of the stop comprises a tab lock recess configured to receive a corresponding ridge provided on a corresponding cassette lid engagement location.

8. The system of claim 7, wherein the ridge extends primarily in a radial direction and has a triangular or semi-circular cross-section.

9. The system of claim 6, wherein each stop comprises a lead-in ramp configured to guide a respective cassette lid engagement location under the bottom surface of the stop.

10. The system of claim 1, wherein the cassette lid further comprises one or more axially-extending ribs.

11. The system of claim 1, wherein the cassette lid engagement locations and the cassette base engagement locations are configured to allow deployment of the cassette lid on the cassette base without visually confirming an orientation of the cassette lid relative to the cassette base.

12. The system of claim 1, wherein n is greater than 1, and the cassette lid engagement locations and cassette base engagement locations are sized and shaped to prevent one of the cassette lid engagement locations from failing to engage a corresponding cassette base engagement location when another of the cassette lid engagement locations successfully engages a corresponding cassette base engagement location.

13. A method of deploying the system of claim 1, the method comprising inserting the cassette lid onto the cassette base, and rotating the cassette lid relative to the cassette base to align the cassette lid engagement locations with the cassette base engagement locations.

14. The method of claim 13, wherein rotating the cassette lid relative to the cassette base comprises applying a lateral pushing force in the axial direction to guide the cassette lid engagement locations into corresponding wells in the cassette base.

15. The method of claim 13, wherein rotating the cassette lid relative to the cassette base comprises pushing the cassette lid engagement locations below corresponding stops on the cassette base.

16. The method of claim 15, wherein a top surface of the cassette lid engagement locations comprises a ridge sized and shaped to fit into a corresponding recess on a bottom surface of the stops and rotating the cassette lid relative to the cassette base causes the ridge to be received in the recess.

17. The method of claim 15, wherein the stops comprise an angled, rounded, or chamfered edge on a bottom surface of a leading edge of the stops, and rotating the cassette lid relative to the cassette base causes a leading edge of the cassette lid engagement locations to meet the bottom surface of the leading edge of the stops and thereby be guided under the stops.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0028] Examples of cassette assemblies with locking and releasing mechanisms will next be described with reference to the following drawings.

[0029] FIG. 1 illustrates an exemplary cassette assembly in accordance with one embodiment.

[0030] FIG. 2A depicts an exemplary embodiment deployed on a different type of cassette.

[0031] FIG. 2B depicts an exemplary embodiment deployed on a different type of cassette.

[0032] FIG. 3 is a close-up of a portion of a cross-sectional view of the cassette assembly in accordance with one embodiment.

[0033] FIG. 4 depicts a cassette assembly having a cassette lid deployed on a cassette base in accordance with one embodiment.

[0034] FIG. 5 is a top view of a cassette base in accordance with one embodiment.

[0035] FIG. 6A depicts a top view the lock and release mechanism of the cassette base.

[0036] FIG. 6B depicts a top view the lock and release mechanism of the cassette base.

[0037] FIG. 7A depicts a bottom view the lock and release mechanism of the cassette base.

[0038] FIG. 7B depicts a bottom view the lock and release mechanism of the cassette base.

[0039] FIG. 7C depicts a bottom view the lock and release mechanism of the cassette base.

[0040] FIG. 8A depicts the use of a secondary hinge in accordance with one embodiment.

[0041] FIG. 8B depicts the use of a secondary hinge in accordance with one embodiment.

[0042] FIG. 9A is a cutaway side view of a lid prior to deployment on a cassette base in accordance with one embodiment.

[0043] FIG. 9B is a cutaway side view of a lid prior to deployment on a cassette base in accordance with one embodiment.

[0044] FIG. 10 is a cutaway side view of a lid after deployment on a cassette base in accordance with one embodiment.

[0045] FIG. 11 is a bottom view of a cassette lid deployed on a cassette base in accordance with one embodiment.

[0046] FIG. 12 is a side perspective view of a cassette lid deployed on a cassette base in accordance with one embodiment.

[0047] FIG. 13A is a side cutaway view of an embodiment employing a z-shaped secondary hinge prior to the cassette lid being deployed on the cassette base.

[0048] FIG. 13B is a side cutaway view of an embodiment employing a z-shaped secondary hinge after the cassette lid being deployed on the cassette base.

[0049] FIG. 14 is a cutaway view of a cassette lid deployed on a cassette base with an interference fit in accordance with one embodiment.

[0050] FIG. 15 is a view of a cassette base having a three-tab locking mechanism in accordance with one embodiment.

[0051] FIG. 16A is a close-up view of a retention tab in accordance with one embodiment.

[0052] FIG. 16B is a close-up perspective view of a retention tab in accordance with one embodiment.

[0053] FIG. 17 is a perspective view of a side of a cassette lid in accordance with one embodiment.

[0054] FIG. 18A depicts a cassette lid prior to deployment on a cassette base in accordance with one embodiment.

[0055] FIG. 18B depicts a cassette lid after deployment on a cassette base in accordance with one embodiment.

[0056] FIG. 19A shows a first step in an installation operation in accordance with one embodiment.

[0057] FIG. 19B shows a second step in an installation operation in accordance with one embodiment.

[0058] FIG. 20A shows a first step in a removal operation in accordance with one embodiment.

[0059] FIG. 20B shows a second step in a removal operation in accordance with one embodiment.

[0060] FIG. 20C shows a third step in a removal operation in accordance with one embodiment.

[0061] FIG. 21 depicts an example of a cassette base having flexure retaining clips in accordance with one embodiment.

[0062] FIG. 22 is a perspective view of a cassette base having flexure retaining clips in accordance with one embodiment.

[0063] FIG. 23 is a close-up view of a cassette base spring flexure in accordance with one embodiment.

[0064] FIG. 24 depicts an example of a cassette assembly with a twist-to-lock mechanism in accordance with one embodiment.

[0065] FIG. 25 depicts an example of a cassette base with engagement locations in accordance with one embodiment.

[0066] FIG. 26A is a top-down view of a portion of a cassette base in accordance with one embodiment.

[0067] FIG. 26B is a top perspective view of another portion of a cassette base in accordance with one embodiment.

[0068] FIG. 27 depicts a cassette lid in accordance with one embodiment.

[0069] FIG. 28 is a side perspective view of a cassette lid in accordance with one embodiment.

[0070] FIG. 29A depicts a first step in an installation operation in accordance with one embodiment.

[0071] FIG. 29B depicts a second step in an installation operation in accordance with one embodiment.

[0072] FIG. 29C depicts a third step in an installation operation in accordance with one embodiment.

[0073] FIG. 29D depicts a fourth step in an installation operation in accordance with one embodiment.

[0074] FIG. 29E depicts a fifth step in an installation operation in accordance with one embodiment.

DETAILED DESCRIPTION

[0075] The cassettes of a microbial detection/enumeration system may be handled several times as the sample is prepared, the cassettes are stacked on the carousel, incubated, and imaged (potentially multiple times over a measurement interval, such as a day, a week, a month, etc.). In order to prevent the cassette from opening and to protect the sample from contamination as the cassette is handled, it can be desirable to maintain the lid securely on the cassette base. However, the lid may also need to be removed, so it is also desirable that the lid can be released. In some cases this can be achieved through a friction fit alone, but in others it would be beneficial to have a releasable locking mechanism that provides a more secure attachment of the lid to the remainder of the cassette.

[0076] In some cases, it may be beneficial if the locking or release mechanism is operable one-handed, so that a user with one occupied hand can still operate the mechanism. Other potentially desirable features (depending on the context or application) may include the ability to lock the lid in place without the need to orient the lid in a particular way relative to the base and/or without the need to visually confirm the orientation of the lid with respect to the base.

[0077] Similarly, it may be desirable to release the lock on the lid without the need to visually confirm the location of a release mechanism (e.g., by releasing the lock through a twisting motion of the entire lid, or by using releases whose location can be confirmed through touch alone).

[0078] Still further, the locking and/or releasing mechanisms should be sufficiently sturdy that they will not break during normal operation of the microbial detection/enumeration system and can continue to function over the expected lifespan of the cassette.

[0079] An example of a cassette assembly 100 is shown in FIG. 1, and a cross-sectional side-view is shown in FIG. 3. The cassette assembly 100 may provide a sterile environment for testing. The cassette assembly 100 may provide an anaerobic or aerobic environment, depending on the application. Note that, for ease of discussion, the splashguard described in more detail below is omitted from FIG. 1 and FIG. 3, but can be deployed in the locations noted in connection with subsequent figures.

[0080] From top to bottom in FIG. 1, the exemplary cassette assembly 100 includes a lid 102, an o-ring 104, an optional foil cutter 106, a scavenging tray assembly 108, a mid-body assembly 110, a membrane filter 120, a second o-ring 112, and a base assembly 114.

[0081] The base assembly 114 forms the bottom-most part of the cassette assembly 100 and serves as a supporting structure to which the other parts can be mounted. The base assembly 114 may be sized and shaped so as to be accommodated in an appropriate testing or analysis device.

[0082] A membrane filter 120 may be provided on the base assembly, between the base assembly 114 and the mid-body assembly 110. The membrane filter 120 may be a part of a media pad sized and shaped to be accommodated by a corresponding recess in the base assembly 114. The membrane filter 120 may be any suitable filter, and may have characteristics (such as a desired porosity) selected based on the particular application (e.g., the size of the microorganisms of interest that are intended to be captured by the membrane filter 120). In some embodiments, more than one membrane filter 120 may be provided, which may include multiple different types of membrane filters 120.

[0083] Target fluids for analysis may be passed through the membrane filter 120 and into the base assembly 114. The base assembly 114 may include a drain port 118 that allows the fluids to be removed from the cassette assembly 100 after filtration. The drain port 118 may include an opening provided in a part of the base assembly 114 internal to the cassette assembly 100 that connects to a specially shaped outlet on the exterior side of the cassette assembly 100. The outlet may be sized and shaped to mate with a drain manifold that receives the removed fluid and delivers it to an appropriate disposal location.

[0084] An o-ring 112 may be provided between the base assembly 114 and the mid-body assembly 110 to prevent fluid from leaking around and therefore bypassing the membrane filter 120. The mid-body assembly 110 includes a mid-body inlet 116 that allows the target fluid (or fluids) being analyzed to be admitted into the cassette assembly 100. The mid-body inlet 116 may include an opening provided in a part of the mid-body assembly 110 internal to the cassette assembly 100 that connects to an opening on the exterior side of the cassette assembly 100. Within the mid-body inlet 116 may be a structure, such as a rubber septum, that seals the cassette assembly 100. To admit a target fluid into the cassette assembly 100, a needle may be used to pierce the structure in the mid-body inlet 116 and deliver the fluid at a relatively high pressure.

[0085] In some embodiments, more than one mid-body inlet 116 may be included in the mid-body assembly 110. For example, one mid-body inlet 116 may be provided for admitting a first sample (target fluid of interest for analysis) into the cassette assembly 100, while a second mid-body inlet 116 is provided for admitting a second, different sample. In other embodiments, a first mid-body inlet 116 may be provided for admitting a sample, while a second mid-body inlet 116 may be provided for admitting a growth medium.

[0086] The top of the mid-body assembly 110 may be shaped to accommodate a scavenging tray assembly 108, which may include a scavenging material that (for example) absorbs oxygen in the cassette assembly 100. The scavenging tray assembly 108 may be topped by foil that holds the scavenging material in place and protects it from outside air until the scavenging tray assembly 108 is deployed in the cassette assembly 100. To release the scavenging material, the cassette assembly 100 may be provided with a foil cutter 106 designed to penetrate the foil and allow the scavenging material to scavenge the environment within the sealed cassette assembly 100.

[0087] To seal the cassette assembly 100, an o-ring 104 may be placed on top of the mid-body assembly 110, and then a lid 102 may be used to cap the entire assembly. As shown in FIG. 3, the o-ring 104 forms a seal between the mid-body assembly 110 and the lid 102 and prevents the fluid from leaking from the top of the cassette assembly 100 (and seals the interior of the cassette assembly 100 to allow the scavenging material to scavenge the environment of oxygen).

[0088] As further shown in FIG. 3, the mid-body assembly 110 may include a mid-body assembly floor 302 that extends from an inner circumferential wall 304 of the mid-body assembly 110 towards an interior of the cassette assembly 100 in the radial direction. The mid-body assembly floor 302 may be slanted towards the membrane filter 120 to encourage the fluid to flow towards the membrane filter 120.

[0089] Although exemplary embodiments are described with reference to the depicted cassette assembly configuration for purposes of illustration, one of skill in the art will recognize that other types of cassette assemblies (with more, fewer, or a different configuration of parts) or other sterile environments may also be used. Moreover, although exemplary embodiments are described in terms of sterility testing using membrane filtration (and the structure in FIG. 1 and FIG. 3 is configured accordingly), other applications of the splashguard described below will be readily apparent.

[0090] FIG. 1 depicts an example of a particular type of cassette, used to test the sterility of a sample. The present invention, however, is not limited to use with a particular type of cassette. For example, FIG. 2A and FIG. 2B depict exemplary embodiments used in connection with simpler sample analysis cassettes. FIG. 2A depicts a cassette with a sample-collecting base assembly 114 and a vision lid 102 employing the snap-lock features discussed herein. FIG. 2B depicts a cassette with a sample-collecting base assembly 114 and a vision lid 102 employing the twist-lock features discussed herein.

[0091] It is often desirable in a microbial detection/enumeration system for the lid 102 to be releasably secured to the base assembly 114 and/or the mid-body assembly 110. Described below are locking mechanisms in the form of hinges and/or twist-lock features that allow the lid 102 to be affixed to the base assembly 114 or mid-body assembly 110 of the cassette and subsequently released.

[0092] Although different variations are discussed below (several examples of hinged mechanisms and twist-lock mechanisms), they rely on common principles and the different structures may be used alone or in combination with each other unless otherwise noted. It is contemplated that the variations may be combined to (for example): provide a lid that is pushed into place and locked with a set (2, 3, or more) of hinged catches and where the hinged catches are released so that the lid can be pulled off; provide a lid that is pushed into place and locked with hinged catches but released through a twisting motion and/or a combination of hinge releases and twisting; provide a lid that is twisted into place and locked, and then twisted to be released; and/or provide a lid that is twisted into place and locked, and then released by activating one or more hinge releases.

[0093] In some situations (e.g., when a user is wearing gloves, as might be the case when users interact with cassettes within an isolator), it can be difficult to rotate the lid to engage a locking mechanism. The clip and hinge embodiments discussed below (the hinged clip, three-tab hinge, and flexure retaining clip) provide cassettes that can lock into place without requiring rotating the lid (although, as noted above, these embodiments can be deployed in combination with a twist-lock mechanism, as the application demands).

Hinged Clip

[0094] FIG. 4-FIG. 13B depict an example of a hinged clip. In these embodiments, the lid 102 is pushed into place, but the lid 102 is not required to be oriented to the base assembly 114 in order to secure the locking mechanism. A rim on the cover engages over a tab on the cassette, where primary hinges deflect to allow the cover rim to pass. More specifically, a tab on the cassette base assembly 114 is displaced by the lid 102. A primary hinge on the tab flexes due to its material properties and then returns to lock the cover into place. The primary hinge may be made of any suitable material, such as metal or plastic, that is capable of flexing or displacing under an applied force but also of returning to its original configuration when the force is removed. In some embodiments, release buttons in the form of secondary hinges are provided. Preferably, two release buttons are provided on opposite sides of the base assembly 114. With this configuration, the lid 102 can be attached to the base assembly 114 with one hand, and can also be removed one-handed by activating the two release buttons with the thumb and forefinger.

[0095] The depicted embodiment includes four primary hinges for locking the lid 102 to the base assembly 114, and two secondary hinges for releasing the lid 102 from the base assembly 114. In the depicted embodiments, the primary hinges and secondary hinges are located on the same mechanism. One of ordinary skill in the art, however, will recognize that a different number and/or configuration of primary and secondary hinges can be used without departing from the principles described below.

[0096] FIG. 5 depicts a base assembly 114 that is generally circular in shape and has a base assembly outer circumferential wall 504 extending around the circumference of the base assembly 114, except in locations where one or more lock and release mechanisms 502 are provided. The outer edge of the lock and release mechanisms 502 may be considered an extension of the base assembly outer circumferential wall 504, except that gap may exist between the base assembly outer circumferential wall 504 and each end of the lock and release mechanism 502. Both the lock and release mechanism 502 and the base assembly outer circumferential wall 504 extend from a base assembly inner circumferential wall 506 that extends around a circumference of an inner portion of the base assembly 114. The base assembly inner circumferential wall 506 is located at a position radially inwards from the base assembly outer circumferential wall 504. The lock and release mechanism 502, base assembly outer circumferential wall 504, and base assembly inner circumferential wall 506 are each shaped with features that interact with and correspond to features on the lid 102, which allows the lid 102 to be locked into place.

[0097] FIG. 6A and FIG. 6B show the lock and release mechanism 502 in more detail. The lock and release mechanism 502 is attached to the base assembly inner circumferential wall 506 through a projecting tab 606 that extends radially outward from the base assembly inner circumferential wall 506. The projecting tab 606 may extend along a circumference of the base assembly inner circumferential wall 506 by a circumferential length, and the lock and release mechanism 502 may extend along a circumference corresponding to the base assembly outer circumferential wall 504 by a circumferential length. The lock and release mechanism 502 may extend beyond the ends of the projecting tab 606; in other words, the circumferential length of the lock and release mechanism 502 may be greater than the circumferential length of the 606 so that distal portions of the lock and release mechanism 502 (to the left and right in FIG. 6A and FIG. 6B) extend beyond the projecting tab 606 and allow a gap to exist between the lock and release mechanism 502 and the base assembly inner circumferential wall 506.

[0098] At the distal-most portions of the lock and release mechanism 502, projections 604 in the form of an angled catch or detent are provided. The area of the lock and release mechanism 502 between the projections 604 and the point at which the lock and release mechanism 502 meets the projecting tab 606 is capable of flexing and serves as a primary hinge 602.

[0099] The primary hinges 602 flex out of the way as the lid 102 is inserted onto the base assembly 114, thereby allowing the lid 102 to be secured to the base assembly 114 through the projections 604 as the projections snap forward (in a radially inward direction) after the lid 102 passes over the base assembly 114. FIG. 7A-FIG. 8B, meanwhile, depict the lock and release mechanism 502 in yet further detail, focusing on the secondary hinges 708. The secondary hinges 708 allow the lock and release mechanism 502 to be released when a force is exerted in a radially inward direction on a portion of the secondary hinge 708 (see FIG. 8A) This causes the secondary hinge 708 to pivot (see FIG. 8B), thereby causing another portion of the lock and release mechanism 502 opposite the pivot from the location of force application to move in a radially outward direction. This action moves the projections 604 away from a corresponding lip on the lid 102, which releases the lid 102 from the base assembly 114.

[0100] FIG. 7A depicts the lock and release mechanism 502 from a bottom perspective. The lock and release mechanism 502 includes a lock and release mechanism outer circumferential wall 702 in a top region (towards the lid 102). The lock and release mechanism outer circumferential wall 702 includes the primary hinge 602 and projection 604.

[0101] The lock and release mechanism 502 further includes a force application pad 706 to which a radially inward force may be applied. The force application pad 706 is attached to the base assembly inner circumferential wall 506 through one or more secondary hinges 708 that serve as pivot points. The secondary hinges 708 may be made of appropriate materials and have appropriate sizes and shapes so as to allow the secondary hinges 708 to flex and then return to their original configuration.

[0102] In the depicted embodiment, the base assembly inner circumferential wall 506 has a particular shape that serves several purposes. For example, the base assembly inner circumferential wall 506 includes a base lower circumferential wall 704 in a bottom region (extending away from the lid 102). The 704 may be spaced radially inward from the force application pad 706 by a predetermined distance (depending on the material properties of the secondary hinge 708) so as to serve as a stop and prevent the force application pad 706 from being pushed beyond a predetermined breaking point. This can help to extend the lifespan of the secondary hinge 708.

[0103] Furthermore, the base assembly inner circumferential wall 506 includes upper features (features extending towards the lid 102) to better allow the lid 102 to be oriented and firmly secured to the base assembly 114. An upper base wall outer wedge 710 projects from the base assembly 114 upwards towards the lid and has a tapered shape. The tapered shape corresponds to a tapered groove or opening in the lid 102, which allows the lid to be captured and oriented more easily on the base assembly 114. Among other advantages, this facilitates one-handed operation when locking the lid 102 to the base assembly 114. The base assembly inner circumferential wall 506 further includes an upper inner base wall 712 to capture and guide the lid 102, as will be discussed in more detail in connection with FIG. 9A-FIG. 9B

[0104] In these Figures, the upper base wall outer wedge 710 and upper inner base wall 712 can be seen as the lid 102 is being inserted onto the base assembly 114 by pushing the lid 102 in a lid insertion direction of force 904 (generally towards the base assembly 114).

[0105] A lid projection 902 extends outward from a lid outer circumferential wall 908 and serves as the lip which the projections 604 will catch. The lid projection 902 may extend around the entirety of the lid outer circumferential wall 908 so that the projection 604 can latch on to any portion of the lid 102 without requiring that the lid 102 be presented in any particular orientation.

[0106] Further facilitating the orientation of the lid 102 with respect to the base assembly 114 for insertion, a tapered lid inner circumferential wedge 906 may be provided. The lid inner circumferential wedge 906 may have a size and shape corresponding to a size and shape of the upper base wall outer wedge 710, and in particular to a size and shape of a gap between the upper base wall outer wedge 710 and upper inner base wall 712. Thus, the upper base wall outer wedge 710 can be captured in a gap between the lid outer circumferential wall 908 and the lid inner circumferential wedge 906, and the lid inner circumferential wedge 906 may be captured in a gap between the upper base wall outer wedge 710 and the upper inner base wall 712.

[0107] As the lid 102 is advanced in the lid insertion direction of force 904, the projection 604 deflects out of the way due to the action/flexibility of the primary hinge 602 as shown in FIG. 10. The projection 604 thus moves in a direction of projection movement 1002, generally a radially outward direction. This allows the lid projection 902 to pass by the projection 604 and into a pocket 1004 between the lock and release mechanism outer circumferential wall 702 and the upper base wall outer wedge 710. After the lid projection 902 moves past the projection 604, the primary hinge 602 biases the projection 604 back into position, pushing the projection 604 back over the lid projection 902. To facilitate the lid projection 902 passing over the projection 604, an upper portion of the projection 604 may be angled down towards the pocket 1004, so that the lid projection 902 is directed towards the pocket 1004. The outer circumferential face of the lid projection 902 may also be angled, rounded, or chamfered.

[0108] The bottom face of the projection 604 may be generally flat, as may the upper face of the lid projection 902. Accordingly, after the projection 604 snaps back into place when the lid projection 902 passes into the pocket, the lid projection 902 cannot generally pass back in a direction opposite the lid insertion direction of force 904 unless and until the projection 604 is moved out of the way through action of the secondary hinge 708. FIG. 11-FIG. 12 show the lid 102 thus secured to the base assembly 114 from bottom and side perspective views.

[0109] FIG. 13A-FIG. 13B show an alternate embodiment in which the secondary hinge 708 takes on a z-shape, as compared to the relatively simple bar-shape in the previously-described embodiments. With this configuration, the secondary hinge 708 may be made stronger and the stress on the hinge may be reduced. More specifically, the secondary hinge 708 joins to the force application pad 706 in an upper region, at the point at which the force application pad 706 meets the primary hinge 602. The secondary hinge 708 then extends downward (away from the lid 102 and towards a bottom of the base assembly 114). The angle of the secondary hinge 708 in this region may depend on a height of the lower portion of the base assembly 114 before the lower wall that defines the bottom of the pocket 1004, and the distance between the force application pad 706 and the base lower circumferential wall 704. Other shapes and designs of hinges can also be used (e.g., I-shaped, a straight hinge, an S-shaped hinge, etc., depending on the application and desired stiffness of the hinge).

[0110] In the depicted embodiment, as well as any of the embodiments that follow, the lid 102 and base assembly 114 may be sized to provide an interference fit, as shown in FIG. 14. Here, a width of the lid inner circumferential wedge 906 (i.e., a distance from the radially innermost wall to the radially outermost wall of the lid inner circumferential wedge 906 may be sized to be smaller than the natural space between the projection 604 (in a resting undeployed, unbiased position) and a radially outer wall of the upper base wall outer wedge 710. The width of the lid inner circumferential wedge 906 may be smaller than this space by a predetermined threshold amount, such as 0.05 mm (although any suitable size may be chosen). With this configuration, the projection 604 will naturally exert an additional radially-inward-facing force on the lid inner circumferential wedge 906 when the lid 102 is secured, which can help to further hold the lid 102 to the base assembly 114. This also helps to prevent gaps from forming between the lid 102 and base assembly 114, which can prevent dehydration of the sample being analyzed within the cassette assembly 100.

Three-Tab Hinge

[0111] Another embodiment of a hinged locking mechanism is shown in FIG. 15 through FIG. 20C. In this embodiment, two or more (preferably three) retention tabs 1502 are provided on the base assembly 114 in place of the previously-described lock and release mechanism 502.

[0112] The principle of operation of the retention tab 1502 is otherwise similar to the lock and release mechanism 502, and the lid 102 and base assembly 114 may be provided with similar interlocking features as the previously-described embodiments. For the sake of brevity, a repeated discussion of these common design features is omitted, although they can generally be seen in FIG. 15 through FIG. 20C.

[0113] The configuration described in these embodiments allows for two different insertion operations. In a first operation, the cover can be pushed into place as in the previously-described embodiments, mostly without concern over the orientation of the cassette. The cassette will be able to lock in place as long as the retention tabs 1502 are not by chance oriented to one of the lid recesses 1702, described below; if this is the case, the lid can be reoriented by a small amount to lock in place. This again allows for one-handed operation.

[0114] In a second operation, the retention tabs 1502 can be intentionally aligned to the lid recesses 1702. The lid 102 can be pushed down onto the base assembly 114 in this alignment, and then the cover can be twisted through a small rotation until the retention tabs 1502 cover a rim on the lid 102. This allows the lid 102 to be locked into place without the retention tabs 1502 needing to deflect, which can increase the lifespan of the device or better align to the preferences of different users.

[0115] To remove the lid 102, the lid 102 can be twisted to re-align the retention tabs 1502 with the lid recesses 1702, after which the lid 102 can be lifted off of the base assembly 114. Alternately or in addition, a secondary hinge may be provided as previous described.

[0116] FIG. 16A-FIG. 16B show the retention tab 1502 in more detail. The retention tab 1502 includes a projection 1602, similar in shape and function to the projection 604 described in connection with previous embodiments. The projection 1602 is provided on the retention tab 1502 adjacent to hinges 1604 similar in function to the primary hinges 602 of the previously-described embodiments. Specifically, hinges 1604 are provided on either side of the projection 1602 and are relatively thin compared to the projection 1602, which allows the hinges 1604 to deflect and carry the projection 1602 out of the way of a lid flange 1704 on the lid 102 (see FIG. 17). A base cutout 1606 adjacent to the hinge 1604 (on an opposite side of the hinge 1604 from the projection 1602) may further improve the flexibility of the hinge 1604 as compared to a design in which the projection 1602 connects directly to a base body outer circumferential wall 1608 on the base assembly 114 that extends around an outer circumference of the base assembly 114. The size and shape of the base cutout 1606 may be selected based on the desired elastic properties of the hinge 1604.

[0117] FIG. 17 depicts the lid 102, which includes a lid flange 1704 which extends around an outer circumference of the lid 102 except in one or more cutaway lid recesses 1702. The lid flange 1704 serves a similar function to the lid projection 902 as described in previous embodiments, and can be similar sized and shaped.

[0118] The number of lid recesses 1702 arranged around the circumference of the lid 102 may correspond to the number of retention tabs 1502 provided in the base assembly 114, and their position on the lid may be established so as to correspond to the positions of the retention tabs 1502 with respect to the base assembly 114.

[0119] A size of the lid recesses 1702 may vary depending on the application. The lid recess 1702 should be at least as wide as the projection 1602 on the retention tab 1502 so that the lid recess 1702 can pass through the projection 1602 when the lid 102 is aligned to the base assembly 114 for installation through a twisting operation (see FIG. 19A and FIG. 19B). The greater the size of the lid recess 1702, the easier it may be to align the lid for the twisting operation. However, if it is contemplated that the lid 102 will primarily be locked to the base assembly 114 by pushing the lid 102 onto the base assembly 114, then a smaller lid recess 1702 may provide more locations at which the lid flange 1704 can lock onto a projection 1602 (thus reducing the number of failed push-to-lock attempts due to chance alignment of the lid recess 1702 with the projection 1602).

[0120] The configurations of the lid 102 and base assembly 114 are shown before (in FIG. 18A) and after (in FIG. 18B) they have been locked together in a push-to-lock type operation. In this embodiment, as in the embodiments previously described, the lid flange 1704 is pushed past the projection 1602 and into a pocket 1802 between the base body outer circumferential wall 1608 and a base secondary circumferential wall 1804. The base secondary circumferential wall 1804 may be tapered similar to the upper base wall outer wedge 710, and previously-discussed features for orienting and capturing the lid 102 to the base assembly 114 (including the aforementioned wedges, circumferential walls, grooves and recesses) may be provided in this embodiment.

[0121] Meanwhile, FIG. 19A-FIG. 19B show the lid 102 being locked to the base assembly 114 through a twisting operation. Here, the projection 1602 may be aligned to the lid recess 1702 within the lid flange 1704 and the lid 102 may be pushed into place (FIG. 19A). Once aligned, the lid 102 and/or the base assembly 114 may be twisted in either direction until the projection 1602 passes over the lid flange 1704, thus locking the lid 102 to the base assembly 114.

[0122] To release the lid 102 from the base assembly 114 (FIG. 20A-FIG. 20C), the lid 102 and/or base assembly 114 may be rotated relative to each other until the projection 1602 aligns to the lid recess 1702. Then, the lid 102 may be lifted off the base assembly 114.

Flexure Retaining Clip

[0123] Another embodiment, which may be employed separately or in conjunction with the above-described embodiments, is shown in FIG. 21-FIG. 23. In these embodiments, one or more (preferably two) flexure retaining clips 2102 are provided on the outer circumference of the base assembly 114. The flexure retaining clips 2102 each include a projection 2110 configured to mate with a suitable projection on the lid 102 as discussed above. A hinge 2108, similar to the hinges discussed above, allow the projection 2110 to be deflected out of the way when the projection on the lid passes the projection 2110. In the depicted example, the hinges 2108 are Z-or C-shaped and allow a force to be applied to a force application pad 2106 to cause a corresponding radially outward motion of an arm 2112 that deflects a projection 2110.

[0124] The projection 2110 is connected to the hinge 2108 via an arm 2112. In contrast to the earlier examples where the hinge was connected to the projection at a point on the base assembly 114 below the projection, the hinge 2108 in this example is attached to base assembly 114 to the side (circumferentially) of the projection 2110. This allows a force to be applied to a force application pad 2106 located on another side (circumferentially) of the hinge 2108 as compared to the projection 2110. Accordingly, a user can apply a force to the force application pad 2106 to divert the arm 2112 and therefore projection 2110 in an outward direction, thus releasing the lid 102 from the projection 2110. A stop 2104 extends a predetermined distance inward from the force application pad 2106. When the user has pushed into the force application pad 2106 with sufficient force to cause the force application pad 2106 to divert by a predetermined amount, the stop 2104 is pushed against an inner circumferential wall of the base assembly 114, thus preventing the hinge 2108 from extending too far and experiencing excessive stress.

[0125] Another feature of the embodiment depicted in FIG. 21-FIG. 23, which may be used in connection with any of the other described embodiments, is a spring flexure 2114. The spring flexure 2114 may be made from the same material as the base assembly 114, or a different flexible material, and is configured to act as a spring. When the lid 102 is pushed onto the base assembly 114, it pushes the arms of the spring flexure 2114 downwards. The arms of the spring flexure 2114 are configured or biased so as to return to their original, upwardly-deflected position, but the lid is held in place by the projections 2110. When a force is applied to the force application pad 2106 and the projections 2110 are moved out of the way, the lid 102 is free to move upwards, away from the base assembly 114. The arms of the spring flexure 2114 can now return to their original, upwardly-deflected configuration, and in so doing will encourage the lid 102 away from the base assembly 114. These features can therefore assist with lid removal.

[0126] In some embodiments, one or more (preferably three) sets of spring flexures 2114 may be provided around the circumference of the base assembly 114. Each spring flexure 2114 may have, for example, two flexible arms extending from a connection point 2304 that connects the spring flexure 2114 to the base assembly 114. The arms may then extend into a gap in the base assembly 114 in a circumferential direction away from the connection point 2304. In a natural, unbiased state, the arms may be configured to extend upwards, away from the base assembly 114 and in a direction from which the lid 102 will approach during an installation operation.

[0127] The arms may be flexible and configured to return to their natural, unbiased state in the absence of an outside force.

Twist-Lock Cassette

[0128] A further embodiment, shown in FIG. 24-FIG. 29E, provides a twist-lock assembly in which the lid 102 can be affixed to (and removed from) the base assembly 114 through a rotation or twisting action, without the need to visually align the lid 102 to the base assembly 114. This configuration provides locking mechanisms at one or more (preferably three) engagement locations 2502 on the base assembly 114 (and corresponding engagement locations 2502 on the lid 102), where the engagement locations 2502 are configured to prevent the lid 102 from being placed on in a crooked or off-alignment orientation. They also prevent the base assembly 114 and lid 102 from being installed and locked together without engaging all of the engagement locations 2502.

[0129] In this embodiment, tab wells 2602 are provided in the base assembly 114 for each of the engagement locations 2502. The base assembly 114 includes an outer circumferential wall 2610 surrounding a circumferential track 2612. The outer circumferential wall 2610 extends higher (i.e., more towards the upward direction from which the lid will be installed) than the circumferential track 2612 and acts as a stop. During installation, the engagement locations 2502 on an outer circumference of the lid 102 will be inserted into the circumferential track 2612; the outer circumferential wall 2610 helps to align the engagement locations 2502 of the lid 102 and guide them the circumferential track 2612.

[0130] The base assembly 114 includes tab lead-in ramps 2604 that guide the engagement locations 2502 from the circumferential track 2612 into a set of tab wells 2602. The tab wells 2602 represent depressions or openings in the circumferential track 2612 that allow the engagement locations 2502 of the lid to drop under cover tab safety stops 2606.

[0131] The cover tab safety stops 2606 may rise from the outer circumferential wall 2610 and thereby provide a tactile indicator of where the locking mechanisms are located. The cover tab safety stops 2606 have a shape to ensure that the locking mechanisms all engage together.

[0132] Specifically, a safety stop trailing edge 2616 of the cover tab safety stop 2606 (i.e., the trailing edge in the forward direction in which the lid 102 is to be rotated; clockwise or to the right in FIG. 26B) is angled, curved, or chamfered. If an engagement location 2502 on the lid is initially deployed directly over top of a locking location (which is generally under and in the center of the cover tab safety stop 2606), then the angled safety stop trailing edge 2616 guides the engagement location 2502 back down in to the circumferential track 2612 and on towards the next cover tab safety stop 2606.

[0133] On the opposite, leading edge of the cover tab safety stop 2606, the edge may be generally flat and perpendicular to the circumferential track 2612. As can best be seen in FIG. 29B, FIG. 29C, and FIG. 29E the bottom corner of the cover tab safety stop 2606 leading edge may be curved, angled, or chamfered, and serves as a tab stop lead-in ramp 2938 to guide the engagement location 2502 on the lid 102 down into the well and under the cover tab safety stop 2606. If the engagement location 2502 on the lid fails to fall into the well, or due to misalignment does not fall far enough to pass under the cover tab safety stop 2606, then the flat leading edge of the cover tab safety stop 2606 meets a flat edge of the engagement location 2502 and prevents it from twisting further. The user can then rotate the lid 102 backwards and re-attempt to lock the lid 102 to the base assembly 114.

[0134] As shown in FIG. 27, each of the engagement locations 2502 extends radially outward from a lip 2808 on an outer circumference of the lid 102. The engagement locations 2502 each include a locking ridge 2706 extending radially outwards along a central portion of the engagement location 2502. The locking ridge 2706 is sized and shaped to fit into a corresponding tab lock 2608 on the bottom of the cover tab safety stop 2606.

[0135] The locking ridge 2706 may be triangular or semi-circular in cross-section. Furthermore, as shown in FIG. 28, the lid 102 may be provided with a series of ribs 2802 to improve grip and handling.

[0136] FIG. 29A-FIG. 29E show an exemplary installation operation and illustrate how the depicted parts work together to lock the lid 102 to the base assembly 114. First, as shown in FIG. 29A, the lid 102 is placed on top of the base assembly 114. If the user happens to place an engagement location 2502 on top of the cover tab safety stop 2606, then the lid 102 can be rotated in a clockwise or counter-clockwise direction so that the engagement location 2502 is initially positioned over the cover tab safety stop 2606.

[0137] In FIG. 29B, the user pushes the lid 102 and the base assembly 114 together (e.g., pushes the lid 102 down onto the base assembly 114) while rotating or twisting the lid 102. This causes the engagement location 2502 on the lid 102 to follow the tab lead-in ramp 2604 down into the tab well 2602 (FIG. 29C).

[0138] As the user continues to rotate the lid 102 so that the engagement location 2502 of the lid 102 is guided by the tab stop lead-in ramp 2938 and passes under the cover tab safety stop 2606, the locking ridge 2706 is guided towards the tab lock 2608. When rotation is complete (FIG. 29E), the locking ridge 2706 is disposed in the tab lock 2608 and locks it in place.

[0139] The operation may be reversed, and the lid 102 removed from the base assembly 114, by rotating the lid 102 in the reverse direction. The curved or angled face of the locking ridge 2706 may press against a wall of the tab lock 2608; the tab cover tab safety stop 2606 may be configured to flex or bend away from the locking ridge 2706 upon application or more than a predetermined amount of force. As the engagement location 2502 continues to rotate, it is guided by the tab lead-in ramp 2604 back up onto the circumferential track 2612. After the engagement location 2502 has cleared the cover tab safety stop 2606, the lid 102 can be lifted free of the base assembly 114.

[0140] Some embodiments may be described using the expression one embodiment or an embodiment along with their derivatives. These terms mean that a particular feature, structure, or characteristic described in connection with the embodiment is included in at least one embodiment. The appearances of the phrase in one embodiment in various places in the specification are not necessarily all referring to the same embodiment. Moreover, unless otherwise noted the features described above are recognized to be usable together in any combination. Thus, any features discussed separately may be employed in combination with each other unless it is noted that the features are incompatible with each other.

[0141] With general reference to notations and nomenclature used herein, the detailed descriptions herein may be presented in terms of program procedures executed on a computer or network of computers. These procedural descriptions and representations are used by those skilled in the art to most effectively convey the substance of their work to others skilled in the art.

[0142] Some embodiments may be described using the expression coupled and connected along with their derivatives. These terms are not necessarily intended as synonyms for each other. For example, some embodiments may be described using the terms connected and/or coupled to indicate that two or more elements are in direct physical or electrical contact with each other. The term coupled, however, may also mean that two or more elements are not in direct contact with each other, but yet still co-operate or interact with each other.

[0143] It is emphasized that the Abstract of the Disclosure is provided to allow a reader to quickly ascertain the nature of the technical disclosure. It is submitted with the understanding that it will not be used to interpret or limit the scope or meaning of the claims. In addition, in the foregoing Detailed Description, it can be seen that various features are grouped together in a single embodiment for the purpose of streamlining the disclosure. This method of disclosure is not to be interpreted as reflecting an intention that the claimed embodiments require more features than are expressly recited in each claim. Rather, as the following claims reflect, inventive subject matter lies in less than all features of a single disclosed embodiment. Thus the following claims are hereby incorporated into the Detailed Description, with each claim standing on its own as a separate embodiment. In the appended claims, the terms including and in which are used as the plain-English equivalents of the respective terms comprising and wherein, respectively. Moreover, the terms first, second, third, and so forth, are used merely as labels, and are not intended to impose numerical requirements on their objects.

[0144] What has been described above includes examples of the disclosed architecture. It is, of course, not possible to describe every conceivable combination of components and/or methodologies, but one of ordinary skill in the art may recognize that many further combinations and permutations are possible. Accordingly, the novel architecture is intended to embrace all such alterations, modifications and variations that fall within the spirit and scope of the appended claims.