“Snap joints can have a variety of geometries, however, the principles of operation remain the same in each case. When two parts are joined using the snap assembly process, a protruding feature on one component, such as a hook or beam, is deflected briefly during the product assembly operation due to an interference, after which the protruding part recovers elastically, and catches in an undercut or indentation on the mating component. The deflection during the assembly operation can be relatively large resulting in high stress or strain levels, however, once the assembly is snapped in place, the components are generally designed to be in a relatively stress free state (unlike press fits)… Snap joints are commonly categorized as (i) snap hooks or beams, (ii) annular or ring snaps, (iii) ball and socket snaps, or (iv) torsional snap joints. Snap joints are further categorized as being either separable or nonseparable... Annular snap joints can be used to assemble rotationally symmetric parts. The annular snap joints shown in figures 6.9 to 6.11 represent common configurations… The most commonly used snap joint utilizes a cantilever beam that deflects and snaps into an undercut on the mating component. These cantilever beam snaps can be designed to be reversible or irreversible, and can be molded directly into the part at the desired locations. The cantilever beams are either an extension of the part walls (i.e. in-plane beams), or extend up (most commonly perpendicular) from the nominal wall (i.e. out-of-plane beams). A variety of cantilever beam configurations are shown in Figures 6.14 to 6.24.”
“i) Notwithstanding that it is not within the literal meaning of the relevant claim(s) of the patent, does the variant achieve substantially the same result in substantially the same way as the invention, i.e. the inventive concept revealed by the patent? ii) Would it be obvious to the person skilled in the art, reading the patent at the priority date, but knowing that the variant achieves substantially the same result as the invention, that it does so in substantially the same way as the invention? iii) Would such a reader of the patent have concluded that the patentee nonetheless intended that strict compliance with the literal meaning of the relevant claim(s) of the patent was an essential requirement of the invention? In order to establish infringement in a case where there is no literal infringement, a patentee would have to establish that the answer to the first two questions was "yes" and that the answer to the third question was "no."”
“A protruding feature on one component being deflected briefly during the product assembly operation due to an interference with a mating component. Once pushed far enough to overcome the force created by the deflection, the protruding part makes a sudden elastic recovery and catches on the mating component. This sudden recovery creates a ‘snap’, providing a tactile and/or audible confirmation of engagement.”
“One component is pushed over another, and the interference between them causes the temporary deflection of one or more elements on one or both components. As the interference stops or reduces, the deflected element(s) recover (either partially or fully) elastically into a mating engagement. There is no requirement for any kind of audible or tactile confirmation of attachment – neither as a matter of wording or as a matter of purpose (the claim covers permanently attaching the components in a factory, where no such confirmation would be required).”
“Having regard to the common general knowledge and the specification …. the skilled person would understand a ‘snap finger’ to be broadly equivalent to the cantilever or beam type ‘protruding feature’ described in Malloy (as opposed to, for example, an annular snap-fit).”
“Snap finger is not a term of art. It simply means that the mating engagement involves an identifiable protruding element. This is not required to have any particular shape or configuration (the so-called ‘fingers’ in the Patent are not shaped like ‘fingers’ – rather they look like trapezoid tabs).”
“29. With the exception of the ambiguous Figure 24, each of the remaining drawings explicitly shows a structure projecting from a wall parallel to the direction of engagement that is designed to be ‘resiliently deflected by and then engage the mating surface, i.e. a classic cantilever or beam snap feature. 30. It is relevant that the specification uses two other terms to describe protruding features which are involved in a snap fit: ‘tang’ and ‘tab’. The term ‘tang’ is used in the specification to describe a variety of protruding features, some but not all of which are engaged in a snap fit: see [0093] and Figure 3; [0112] and Figure 17; [0113] and Figures 18, 19 and 20. 31. The term ‘tab’ is also used to describe a variety of protruding features, again some but not all of which are engaged in a snap fit. See [0044] and Figures 38.1-38.5; [0046] and Figures 39.1-39.6 [0099] and Figures 27-30; [0116], [0117] and Figures 14, 15, 17 and 21, 22, 23; [0131] and Figures 42.1-42.7. In some of these Figures, the precise nature of the ‘tab’ structure is unclear. However, where the nature of the structure is clear, the word appears to be used to describe a projection which is not designed to deflect. See in particular, [0044] and Figures 38.1-38.5; [0046] and Figures 39.1-39.6; [0116], [0117] and Figures 14, 15, 17 and 21, 22, 23.”
“As a matter of ordinary language, and consistent with the specification (see [0117] in particular), a collar which ‘includes one or more protrusions’ requires a distinct structure to protrude from the collar, rather than being satisfied by the basic shape of the collar itself.”
“The purpose of the protrusion(s) referred to in claim 12 is specifically to engage the respective snap fingers. A protrusion is satisfied by any ‘higher’ area of the surface of the collar which creates a mating engagement with the ‘finger’ when it has snapped into place.”
“In summary, there is a mask shell (12), which connects (via parts 16 and 18) to a mask seal (14) (i.e. the cushion). A headstrap retention bracket (20) attaches to the mask shell, and a dual swivel configuration (22) allows connection to a gas supply hose (not shown).”
“222. In reaching this view, I am of course conscious of the fact that the two snap fingers coloured red do not look like typical fingers, in the sense that they do not 'poke out' above the surrounding surface of the retainer bracket. However, from a functional perspective, there's really no difference at all; they are still two protrusions which snap into complementary recesses. If I am wrong, and these weren't considered to be snap fingers, as I explained in paragraph 74 above, it was well known that snap fit connections could come in many different forms, shapes or positions, some of which would include a finger-like protrusion snapping into a complementary recess. The skilled person would certainly appreciate that the connection between the retainer and the frame could be easily re-designed with more finger-like protrusions to achieve the snap fit as a simple design alternative.”