Abstract:
A vent assembly, suitable for marine use including, for example, venting an enclosure, such as an engine compartment, on a boat. The vent assembly has substantially the external appearance of a cast or machined, one piece, stainless steel vent, at a cost very little more than a molded plastics vent. A molded plastics vent has a head perforated by a pattern of ventilating slots separated by flanking strips. A decorative, corrosion-resistant, sheet metal cover shell lies tight against the front side of the molded plastics vent and has a pattern of slots and strips mapping substantially on the pattern of slots and strips of the molded plastics vent. Snap-fit fasteners fix the cover shell on the vent so that the cover shell slots are a substantially flush continuation of the vent slots, so as to provide the decorative appearance of a solid metal vent at substantially lower cost and without compromising or through flow capability.

Description:
FIELD OF THE INVENTION  
       [0001]     This invention relates to slotted vents, and more particularly to slotted vents usable in marine applications such as for ventilating a motor enclosure on a boat.  
       BACKGROUND OF THE INVENTION  
       [0002]     U.S. Pat. No. 5,588,908, assigned to the assignee of the present invention, discloses a apparatus for fixing a ventilating hose at an opening in a wall of an enclosure, e.g. for use on a boat in venting gases from the engine compartment, or venting cooking odor laden air from the galley, or admitting air. That apparatus includes a vent fitting comprising a radially extended, slotted head adapted to rest against the exterior face of the wall to hide an opening therein and a tubular body extending from the rear face of the head through the wall opening, to fix the vent fitting and an attached, rearwardly extending hose to the wall at the opening, to communicate flow through the hose and slotted head. To accomplish its various purposes, such vent fitting is of relatively complex form. Despite this, the assignee of the present invention has succeeded in forming such fittings of molded plastics material at relatively low cost and has successfully marketed units in substantial quantities, for example to boat manufacturers.  
         [0003]     However, the present assignee has found that for more expensive lines of boats, boat manufacturers and their buyers prefer more expensive looking fittings, e.g. stainless steel fittings, rather than less expensive looking molded plastics fittings.  
         [0004]     With that in mind, the present assignee has marketed molded plastics fittings of this general type with exposed surfaces chromium plated, by a conventional process, to achieve the richer, more expensive appearance of a polished metal fitting. While generally successful commercially, the present assignee has found that continuing contact, over a long period of time, with the elements in a harsh salt water marine environment, may attack, and eventually degrade the appearance of, the plated visible surfaces of such fittings.  
         [0005]     Accordingly, the present assignee has considered producing such fittings of corrosion resistant metal, such as stainless steel, as by casting or machining, and while such product is durable and can maintain a rich, expensive appearance over long periods of use, it is many times more expensive to produce than the same product of molded plastics material, and because of this expense would have a very limited market.  
         [0006]     The purposes of the present invention include overcoming these conflicting prior difficulties.  
       SUMMARY OF THE INVENTION  
       [0007]     This invention relates to a vent assembly, suitable for marine uses including, for example, venting an enclosure, such as an engine compartment, on a boat, which vent assembly has substantially the external appearance of a cast or machined, one piece stainless steel vent, at a cost very little more than a molded plastics vent. 
     
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       [0008]      FIG. 1  is a pictorial view of a prior molded plastics vent substantially as disclosed in U.S. Pat. No. 5,588,908 assigned to the assignee of the present invention.  
         [0009]      FIG. 2  is an enlarged cross-sectional view of the  FIG. 1  molded plastics vent.  
         [0010]      FIG. 3  is a pictorial view of a cover shell of convexly curved shape, taken from the front side thereof, and in accord with a preferred embodiment of the present invention.  
         [0011]      FIG. 4  is a pictorial view of the  FIG. 3  cover shell taken from the rear side thereof.  
         [0012]      FIG. 5  is a front view of the  FIG. 3  cover shell.  
         [0013]      FIG. 6  is an enlarged fragmentary cross-sectional view substantially taken on the line  6 - 6  of  FIG. 5 .  
         [0014]      FIG. 7  is an enlarged, fragmentary cross-sectional view substantially taken on the line  7 - 7  of  FIG. 5 .  
         [0015]      FIG. 8  is a pictorial view of a preferred embodiment of a molded plastics vent for which the  FIG. 3  cover shell is intended.  
         [0016]      FIG. 9  shows  FIG. 6  cover shell installed on a molded plastics vent like that of  FIG. 8 .  
         [0017]      FIG. 10  shows the  FIG. 7  cover shell installed on a molded plastics vent of the type shown in  FIG. 8 .  
         [0018]      FIG. 11  is an enlarged fragmentary cross-sectional view substantially taken on the line  11 - 11  of  FIG. 5 , and showing the cover shell installed on the  FIG. 8  vent.  
         [0019]      FIG. 11A  is a fragment of  FIG. 11 , but showing the  FIG. 3  cover sheet tab at a starting position of installation on the  FIG. 8  vent.  
         [0020]      FIG. 11B  is similar to  FIG. 11A , but showing an intermediate position of installation. 
     
    
     DETAILED DESCRIPTION  
       [0021]     A vent  40  ( FIGS. 1 and 2 ) is here formed to function as a hose fitting. The vent  40  is formed (preferably molded) of a suitable substantially rigid molded plastics material, such as nylon or polypropylene. The molded plastics vent  40  includes a radially extending head  42 , here in the form of a circular face plate. The head  42  has a radially outward facing edge  30  and a continuous peripheral edge portion  43  inboard of the edge  30 . The head  42  is perforated by a pattern of elongate ventilating slots  31  extending axially therethrough and laterally to the peripheral edge portion  43 . The slots  31  have end walls  32  at the peripheral edge portion  43 . The slots are separated by flanking straps  46  defining side walls  33  of the slots  31 . The head  42  has front and back sides  20  and  21  respectively separated by the radially outward facing edge  30  and to which the slots  31  open.  
         [0022]     The molded plastics vent  40  also has a generally tubular base  50  extending substantially coaxially from the back side  21  of the head  42  at its peripheral edge portion  43 . The base  50  is spaced inboard of the radially facing edge  30  by a coaxial, radially extending, rear facing, enclosure wall abutting, annular lip  49  and has a coaxial through passage  51  communicating with the slots  31 .  
         [0023]     In the embodiment shown in  FIGS. 1 and 2 , the generally tubular base  50  is circumferentially segmented to form circumferentially closely spaced, alternating lock tabs  45  and locking fingers  52 , all of which extend axially rearwardly from the head back side at the peripheral edge portion  43 . The lock tabs  45  and fingers  52  are of arcuate, circumferentially extending cross-sectional profile. The rear edges of the lock tabs  45  are radially inwardly beveled at  47 .  
         [0024]     The locking fingers  52  are located slightly radially outwardly from the lock tabs  45 . Each locking finger  52  has one or more (here three) axially spaced, radially outwardly protruding, circumferentially extending teeth  54  having a rearward and radially outwardly beveled, generally rearwardly facing surfaces  56 . The rearwardmost tooth  54  forms the rear edge of the base  50  and its beveled surface  56   a  extends the full radial thickness of the tooth. The rearward end portion of each locking tooth  52  is thickened to provide a slightly radially inwardly protruding lip  60 . The teeth  54  and lip  60  extend circumferentially the width of the locking finger  52 . It will be understood that the locking fingers  52 , including their lips  60 , are spaced radially outward from the outer circumferential plane of the lock tabs  45  and preferably are circumferentially narrower than the circumferential spaces between the lock tabs  45 . Circumferentially spaced, axially extending, reinforcing, rib-like webs  58  protrude radially outwardly from the radially outer face of the locking fingers  52  between the back side  21  of the head  40  and the nearest tooth  54 .  
         [0025]     The molded plastics vent  40  can be used as an end termination for a ventilation hose  10  ( FIG. 2 ), a ventilating member to provide a finished appearance for a hole  14  in a wall  12 , or both. In the embodiment shown, the hose  10  is formed of a flexible material in which a coiled wire  64  is embedded for reinforcement. The front (leftward in  FIG. 2 ) end of the hose is forwardly inserted into the circumferentially continuous, radially narrow, annular space between the lock tabs  45  and locking fingers  52  so as to closely approach or abut the back side  21  of the head  42  of the molded plastics vent  40 , as permitted by the limited radial bending capability at least of the fingers  52 . So installed, the radially inwardly protruding lips  60  on the fingers  52  axially fix the hose  10  to the molded plastics vent  40  and prevent unintended axial separation thereof. With an intermediate portion of the hose  10  extending through the hole  14  in the wall  12 , rearward movement of the molded plastics vent  40  toward the wall  12 , coaxially of the hole  14 , inserts the generally tubular base  50  into the hole  14 , such that the teeth  54  slide axially rearwardly along the peripheral edge of the hole  14 , camming and bending the fingers  52  radially inwardly as needed, until the radially extending head  42  of the vent  40  abuts the front face of the wall  12 , thereby completing installation as seen in  FIG. 2 .  
         [0026]     During installation, the tapered rearward surfaces of the teeth  54  assist installation of the vent  40  in the wall  12 , whereas after installation the forward facing radially planar faces of the teeth  54  resist removal of the vent  40  from the wall  12 . The radially inward bending of the locking fingers  52  by the peripheral edge of the hole  14  helps the lips  60  of the fingers  60  fixedly grip the hose  10  between themselves and the circumfererentially flanking tabs  45 .  
         [0027]     To the extent of above discussed, the apparatus is substantially that disclosed in the present assignees prior U.S. Pat. No. 5,588,908.  
         [0028]      FIG. 8  shows a further prior art vent  140  which may be generally similar to the vent  40  above discussed with respect to  FIGS. 1 and 2 , except as follows.  
         [0029]     For example, the head  142  ( FIG. 8 ) of the vent  140  has a front side  120  of shallow, convexly rounded shape. Thus, the strips  146  have correspondingly somewhat convexly rounded front faces  147 .  
         [0030]     Turning now to aspects of the apparatus more directly dealing with the present invention, attention is directed to  FIGS. 3-11 .  
         [0031]     A radially extending cover shell  201  ( FIGS. 3-5 ) is preferably of a decorative, corrosion resistant, relatively stiff material, such as sheet metal. In the preferred embodiment shown, the cover shell  201  is of stainless steel sheet. Marine grade stainless steel sheet is sufficiently corrosion resistant, even in salt water environments, as to maintain a decorative appearance over a long period of time.  
         [0032]     The cover shell  201  has a continuous peripheral edge portion  205  surrounding a central portion  206  comprising a pattern of slots  211  separating by elongate strips  206 , whose edges define corresponding edges of the flanking slots.  
         [0033]     The cover shell  201  has a front face  220  ( FIG. 3 ) and a back face  221  ( FIG. 4 ). The cover shell  201  is contoured three-dimensionally to continuously snugly cover, in a skin-like manner, the front side of the head of a corresponding molded plastic vent. Thus, in the embodiment shown, the cover shell  201  of  FIGS. 3-5  is three-dimensionally contoured to cover the convex front face  147  of the corresponding vent  140  of  FIG. 8 , it being understood that similar cover shells can be three-dimensionally configured to similarly fit, in a skin-like manner, the front face of the head of otherwise contoured vents, for example such as the vent  40  in  FIGS. 1 and 2  above-described, the front face  20  of which is not convexly rounded, but rather is flat (or might be concavely rounded if desired).  
         [0034]     Returning to the particular cover shell  201  shown in  FIGS. 3 and 4 , same thus is contoured three-dimensionally in a shallow, cup-like shape having a convexly rounded front wall  226  incorporating the slots  211  and strips  216  and a peripheral wall continued therefrom and terminating in a peripheral edge  228 .  
         [0035]     The cover shell  201  is three-dimensionally contoured so that its back side  221  can continuously abut the front face  147  ( FIG. 8 ) of the supporting vent  140 , in the manner shown in  FIGS. 6, 7  and  9 - 11 . In other words, the cover shell  201  is contoured to fit in a skin-like manner on the front of the supporting vent head  142 .  
         [0036]     The pattern of slots  211  and strips  216  of the cover shell  201 , as well as the size, shape and placement thereof, are preferably identical to those of the slots  131  and strips  146  of the corresponding vent  140 . Thus, with the cover shell  201  properly oriented on the front face  147  of the vent head  142 , the vent head  142  is to be entirely hidden from the front by the cover shell  201 , as in  FIG. 5 . Thus, the cover shell  201  is to cover the entire exposed portion (the front and periphery) of the vent head  142 , including the front surfaces of the strips  146 , the peripheral edge portion  143 , and the radially outwardly facing peripheral edge  130 . Thus, at least as a casual observer, the external appearance of the vent assembly, comprising the molded plastic vent  140  and cover shell  201 , is to be that of a monolithic metal (e.g., stainless steel) vent cast from molten stainless steel or machined from a block of stainless steel. This visual effect can be enhanced by reducing the visibility of the molded plastics vent  140 . For example, by molding the plastics vent  140  of a black material with a non-shiny surface, the sidewalls  133  ( FIGS. 8 and 9 ) of the vent head strips  146  may visually merge into the shadowed interior reaches of the vent slots  131 .  
         [0037]     In some embodiments, as for example shown in  FIG. 8 , at least some of the vent head strips  146  may be, as seen from the front, several times longer than their width. Despite this, such strips  146  may be made especially strong by providing same with substantial front-to-rear depth, as seen for example in  FIGS. 8 and 9 , wherein the strips  146  crossing the central portion of the head  142 , while laterally longer, are also deeper front-to-rear. On the other hand, the cover shell  201  is preferably of constant thickness sheet material and indeed very thin compared to any dimension of the vent strips  146 .  
         [0038]     Thus, to avoid accidental bending after the cover shell  201  is formed, the longer cover shell strips  216  may be reinforced by one or more cross straps  234  ( FIGS. 3-7 ) spanning one or more of the slots  211  and extending transversely from the flanking strips  216 . A given cross strap  234  thus acts to prevent twisting (about its length axis) or bending (out of its plane or transversely into or away from a flanking slot) of the attached strip  216 . So that the cross straps  234  do not significantly impede flow through the slots  211 , the cross straps  234  are preferably minimized in number and length, so that the total frontal area of the cross straps  234  is small compared to the total frontal area of the slots  211 .  
         [0039]     The cover shell  201  can be fixed to the front of the vent head  142  as desired, for example by adhesive bonding. However, in the preferred embodiment shown, the cover shell  201  is preferably securely but resiliently releasably snap-fitted to the front of the vent head  142  by its own monolithically integrated fastening structure. In the preferred embodiment shown, that fastening structure comprises resiliently bendable, cantilevered tabs  250  ( FIGS. 3, 4 ,  7 ,  8 ,  10  and  11 ) angled substantially rearwardly from edges of corresponding slots  211 . Advantageously, the tabs  250  extend from ends  251  of one or more of the shell slots  211  and are hence rearwardly bent from inboard edges of the peripheral edge portion  205  of the cover shell  201 . Such tabs  250  are thus located to extend into adjacent vent head slots  131  ( FIG. 11 ), here at opposite ends of the two adjacent longest ones of the vent head slots  131 . A given said tab  250  ( FIG. 11 ) has a leg  254  extending rearwardly and positioned to lie along and adjacent the opposed vent head slot end  132 . Such tab  250  further includes a heel  256  protruding from the free rear end of the leg  254  and positioned to lie laterally beyond the vent head slot end  132  and snugly behind the vent head peripheral edge portion  143  to lock the cover shell  201  against the front face  147  of the vent head  142 . Such tab  250  further includes a foot  258  extending rearward from the radially outboard end of the heel  256  and a toe  260  angled rearward and radially inward from the free, rear end of the foot  258 .  
         [0040]     Applicants found that the cover shell  201  can be inexpensively produced from stainless steel sheet by a stamping operation which separates the cover shell  201  from the surrounding portion of the parent metal sheet (not shown), removes material to form the slots  211  and flanking strips  216 , forms the mentioned cup-shaped configuration and forms and bends out of plane the mentioned tabs.  
         [0041]     To install the cover shell  201  on the vent  140 , the cover shell is moved rearward toward the front of the vent  140  to cammingly engage the rear face of the toe  260  ( FIG. 11A ) with the front inboard corner of the vent peripheral edge portion  143  at the appropriate slot end wall  132 . Continued rearward displacement of the cover shell  201  causes the vent edge portion  143  to cam the cover shell toe  260  laterally inboard (leftward in  FIGS. 11A and 11B ), resiliently bending the tab  250  leftwardly and allowing the heel  256  to slide rearwardly along the corresponding vent slot end wall  132  toward and past its  FIG. 11B  partially installed position. Continued rearward displacement of the cover shell  201  brings same into the firm, face-to-face contact with the vent  140 , as shown in  FIGS. 9-11 , whereupon the resiliently bent tab  250  snaps its heel  256  ( FIG. 11 ) laterally outward snugly behind the vent edge portion  143 . With the tabs  250  (four being provided in the embodiment shown) thus deployed, same firmly and fixedly retain the cover shell  201  tightly against the front of the vent head  142 , as generally shown in  FIGS. 9-11 .  
         [0042]     Thus installed, it will be noted that the back side  221  ( FIGS. 9-11 ) of the cover shell  201  tightly continuously abuts the front side  147  of the vent head  142 , with the continuous peripheral edge portion  205  of the cover shell mapping on the head peripheral edge portion  143  and the shell peripheral edge  228  lying flush with the rear facing lip  149  of the vent head  142 , as seen in  FIGS. 9 and 10 . Moreover, the pattern of cover shell slots  211  maps on the pattern of vent head slots  131  in shape, size and relative location ( FIGS. 9 and 11 ) and the cover shell strips  216  map on the vent head strips  146  in shape, size and relative location. Thus, the edges of the shell slots  211  are a substantially flush forward continuation of the walls of the corresponding head slots, so as to minimize disruption of air flow through the vent head  142  despite the covering thereof by the cover shell  201 . In the  FIGS. 3-11  embodiment, one or more of the cover shell strips  216  is relatively long and narrow, and one or more rigidifying cross straps  234  are integrated in the cover shell  201  and span one or more cover shell slots  211  and corresponding vent slots  131  but, as indicated in  FIG. 9 , the cross straps  234  are minimized in width and number, and so do not significantly, if at all, impede air flow through the vent  140 .  
         [0043]     In a preferred embodiment of the invention, the cover shell  201  was stamped of grade  316  stainless steel sheet material of thickness about 0.5 mm, though use of similar material of thickness in the range 0.2-1.0 mm is contemplated.  
         [0044]     The use of thicker material may be desirable where the cover shell is of greater diameter, has a more flat or otherwise less inherently rigid cross-sectional shape, has longer and/or narrower strips  216 , has longer and/or wider slots, or has fewer (or no), narrower and/or longer cross straps  234 . The cover shell thickness may also be varied to compensate for variations in rigidity as between different cover shell materials.  
         [0045]     While the vent  140  and cover shell  201  here shown by way of illustration have a pattern of substantially parallel, chordally extending, uniform width slots  211 , the pattern of slots  211  may be varied as desired in shape, size and relative location within the broader scope of the invention. For example, the slots  211  could take the form of a plurality of circular or irregularly shaped holes, and/or nonparallel (e.g. radiating) elongate openings as desired.  
         [0046]     In accord with the present invention, the rigidity, frontal impact resistance, and resistance to denting of the vent assembly  140 ,  201  is provided primarily by the relatively inexpensive, rigid molded plastics vent  140  which firmly backs the cover shell  201 . Thus, the thickness of the cover shell  201 , including its strips  211 , may be a very small fraction (e.g. 1/20 to 1/80) of the thickness of the vent head strips. For example, in the embodiment shown, the cover shell strip thickness is about 1/40 th  of that of the thickest vent head strips  146 .  
         [0047]     Thus, the vent assembly  140 ,  201  according to the present invention, as compared to a monolithic cast or machined vent of solid stainless steel, is substantially more economical both in terms of substituting less expensive plastics material for the great majority of more expensive stainless steel, and in substituting less costly fabrication methods (e.g., relatively inexpensive plastic molding and sheet metal stamping operations) for more expensive stainless steel casting or solid-block machining.  
         [0048]     Although a particular preferred embodiment of the invention has been disclosed in detail for illustrative purposes, it will be recognized that variations or modifications of the disclosed apparatus, including the rearrangement of parts, lie within the scope of the present invention.