Abstract:
An externally threaded nipple ( 24 ) fits through a circular opening ( 38 ) in a flexible wall ( 14 ). The nipple ( 24 ) is carried by a first ring member ( 18 ). An internally threaded second ring member ( 20 ) is screwed onto the nipple ( 24 ). The first and second ring member ( 18, 20 ) become connected together and the portion of the flexible wall ( 14 ) that immediately surrounds the opening ( 38 ) is trapped by and between two inner side surfaces ( 30, 36 ) of the two ring members ( 18, 20 ). Projecting portions ( 50 ) on one of the inner side surfaces are urged against the wall ( 14 ) to inhibit rotation of the attachment ( 16 ). One of the ring members ( 18, 20 ) has louvered fins ( 42 ) interconnected by strengthening ribs ( 44 ).

Description:
TECHNICAL FIELD 
     This invention relates to the ventilation of enclosures that are at least in part formed by a flexible wall. More particularly, the invention relates to the provision of a vent forming attachment for a flexible wall comprising two members that are brought together from opposite sides of the flexible wall and are screwed together where they meet at an opening in the flexible wall, for securing them together and to the flexible wall. 
     BACKGROUND OF THE INVENTION 
     Vent forming attachments for flexible wall enclosures are disclosed by the following U.S. Pat. No. 2,939,375, granted Jun. 7, 1960 to J. Herman; U.S. Pat. No. 3,024,717, granted Mar. 13, 1962 to Edward G. Rozek; U.S. Pat. No. 3,892,169, granted Jul. 1, 1975 to Frank R. Jarnot; U.S. Pat. No. 4,184,414, granted Jan. 22, 1980 to Frank R. Jarnot; U.S. Pat. No. 4,379,468, granted Apr. 12, 1983 to Steve Szukhent; and U.S. Pat. No. 4,625,468, granted Dec. 2, 1986 to Viktor E. Hampel. 
     The vent forming attachments disclosed by these patents are relatively complex in construction and are difficult to install and may lack a firm attachment to the wall structure when installed. There is a need for a vent forming attachment that is simple in construction, has a very few parts, is easy to attach, and, when attached, makes a secure connection with the wall structure. An object of the present invention is to provide a vent forming attachment that fulfills this need. 
     BRIEF SUMMARY OF THE INVENTION 
     The present invention provides a vent forming attachment for a flexible wall. The attachment is attachable to the wall at an opening in the wall. According to an aspect of the invention, the attachment comprises a first ring member and a second ring member. The first ring member has an axial center opening that is radially outwardly bounded by an axial nipple that is sized to fit into the opening in the wall. The nipple includes a base and external threads that extend axially from the base. The first ring member also includes a first inner side surface that extends radially outwardly from the base of the nipple. The second ring member has an axial center opening that includes internal threads that match and mate with the external threads on the nipple. The second ring member also has a second inner side surface that extends radially outwardly from the center opening in the second ring member. The first ring member is positionable with its nipple in the opening in the wall and its inner side surface against a first side of the wall. The second ring member is positionable with its inner side surface directed toward a second side of the wall opposite said first side of the wall, and is rotatable to cause its internal threads to threadedly engage the external threads on the nipple of the first ring member. This positioning and rotation causes the first and second ring members to become connected together and a portion of the wall that immediately surrounds the opening in the wall to be trapped by and between the two inner side surfaces of the two ring members. One of the ring members has projecting portions on the inner side surface thereof configured to be urged against said portion of the wall when the first and second ring members are connected together to trap said portion of the wall. This inhibits rotation of the attachment relative to the wall. In addition, one of the ring members has a plurality of fins extending across its axial center opening to form a louvered opening. A plurality of ribs perpendicular to the fins extend between and interconnect each pair of adjacent fins to strengthen the fins. 
     Both the projecting portions and the fins may be provided on only one of the ring members or on both of the ring members. A ring member including fins may also include projecting portions. Alternatively, the projecting portions may be provided on a different ring member that does not include fins. 
     The projecting portions on the inner side surface may have various configurations. Preferably, the projecting portions comprise a plurality of pointed raised dimples. In the preferred embodiment, these dimples are circumferentially spaced around the circumference of the inner side surface. The projecting portions may also take various other configurations. For example, the portions may form an annular ridge or a spiral ridge extending around the inner side surface. Either type of ridge might be continuous or formed of a plurality of spaced sections. 
     Flow passageways for air to allow the desired venting action are provided between adjacent fins. If it is desired to divide these flow passageways into smaller passageways sufficiently small to inhibit passage of insects through the attachment, the attachment may also be provided with a screen. Such a screen would preferably be carried by the first ring member and cover the center opening of the first ring member. 
     To improve the appearance of the attachment and minimize any obstruction of flow through the attachment without sacrificing strength, the ribs that interconnect the fins have a preferred configuration. In this configuration, each fin is downwardly angled, as in most known louvered structures. Each rib connects a mid portion of a lower surface of a first fin and a mid inner portion of an adjacent upper surface of a second fin. This leaves an outer portion of the upper surface free from connection to the rib. The resulting configuration tends to direct flow around the ribs and on through the center openings of the attachment along the upper surface of the second fin adjacent to the rib. As used in reference to the fins, the term “mid” refers to a middle position in a chordwise direction of the attachment, and the terms “inner” and “outer” refer to a position in the axial direction of the attachment with “inner” being relatively close to the axial center of the attachment. 
     As used herein, the terms “downwardly”, “lower”, “upper”, and the like refer to the use orientation illustrated in FIGS. 2-8. 
     These and other advantages and features of the invention will become apparent from the detailed description of the invention set forth below. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     In the drawings, like element designations refer to like parts throughout, and: 
     FIG. 1 is a fragmentary pictorial view of an enclosure for the pilothouse of a power boat, showing a vent forming attachment mounted at an upper side region of the enclosure in a plastic window portion of the enclosure. 
     FIG. 2 is an enlarged scale pictorial view of the plastic window portion of FIG. 1 where the vent forming attachment is mounted. 
     FIG. 3 is an exploded pictorial view of a preferred embodiment of the vent forming attachment of the present invention, such view being taken from above and looking towards the top, one side, and the louvered front of the attachment. 
     FIG. 4 is an axial sectional view taken substantially along line  4 — 4  of FIG. 2, showing the vent forming attachment of FIG. 3 mounted onto a flexible wall in the region of an opening in such wall. 
     FIG. 4A is an enlarged scale fragmentary view of the upper portion of FIG. 4 within the broken line circle of FIG.  4 . 
     FIG. 5 is a pictorial view of the attachment shown in FIG. 3 in an assembled condition. 
     FIG. 6 is a front elevational view of the attachment shown in FIG.  5 . 
     FIG. 7 is a side elevational view of the attachment shown in FIGS. 5 and 6. 
     FIG. 8 is a rear elevational view of the attachment shown in FIGS. 5-7. 
     FIG. 9 is an elevational view looking toward the top of the attachment shown in FIGS. 5-8. 
     FIG. 10 is an elevational view looking toward the bottom of the attachment shown in FIGS.  5 - 9 : 
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
     FIG. 1 shows a forward portion of a power boat  10  having a cover  12  that, together with a portion of the main structure of the power boat  10 , forms an enclosure for a pilothouse where the steering mechanism, etc. is located. The cover  12  includes top, front, and side portions. The side portions include flexible and transparent walls that serve as windows. A window area of one of the side portions  14  is shown to be provided with a vent forming attachment  16 . FIG. 2 is an enlarged view of this area. 
     Referring to FIGS. 3 and 4, in preferred form, the vent forming attachment  16  comprises first and second ring members  18 ,  20 . The ring members  18 ,  20  preferably have a circular configuration. The first ring member  18  includes an axial center opening  22  that is radially outwardly bounded by an axial nipple  24 . Nipple  24  includes external threads  26  that extend axially outwardly from a nipple base  28 . Ring  18  also includes an inner side surface  30  that extends radially outwardly from the nipple base  28 . The second ring member  20  includes an axial center opening  32  having internal threads  34  that are sized to match and mate with the external threads  26  on the nipple  24 . Ring member  20  also includes an inner side surface  36  that extends radially outwardly from the threads  34  of the center opening  32 . 
     The attachment  16  is attachable to the flexible wall  14  of the window area at an opening  38  in the wall  14 . The nipple  24  is sized to fit into the opening  38 . The first ring member  18  is positioned with its nipple  24  extending into the opening  38  and its radial inner side surface  30  against a first side of the wall. The second ring member  20  is positioned with its radial inner side surface  36  directed toward a second side of the wall opposite the first side of the wall contacted by the surface  30  of the first ring member  18 . The second ring member  20  and/or the first ring member  18  is rotated to interengage the external and internal threads  26 ,  34 . Preferably, the first ring member  18  is held stationary to maintain it in the horizontal use orientation illustrated in the drawings, and the second ring member  20  is rotated. This causes the internal threads  34  on the second ring member  20  to threadedly engage the external threads  26  on the nipple  24  of the first ring member  18 . The first and second ring members  18 ,  20  become connected together, and a portion of the wall  14  immediately surrounding the opening  38  in the wall  14  is trapped by and between the two inner side surfaces  30 ,  36  of the two ring members  18 ,  20 . The trapping of the wall  14  is illustrated in FIGS. 4 and 4A. 
     As the second ring member  20  is being rotated, its inner side surface  36  is moved toward the wall  14 . Ring member  20  is preferably rotated until its inner side surface  36  bears tightly against the portion of wall  14  immediately surrounding the opening  38  in the wall  14 . As the inner side surface  36  on the second ring member  20  moves against one side of the wall  14 , the inner side surface  30  on the first ring member  18  is moved against the opposite side of the wall  14 . 
     At least one of the ring members  18 ,  20  is preferably provided with projecting portions on its inner side surface  30 ,  36 . The projecting portions are configured to be urged against the wall  14  when the first and second ring members  18 ,  20  are connected together to trap the wall  14 . In the illustrated preferred embodiment, the inner side surface  30  of the first ring member  18  has projecting portions in the form of a plurality of pointed raised dimples  50  formed on the surface  30 . As the two inner side surfaces  30 ,  36  are brought into gripping contact with the wall  14 , the dimples  50  dig into the material of the wall  14 , as illustrated in FIGS. 4 and 4A. The dimples  50  are evenly spaced around the circumference of the inner side surface  30  so that the gripping of the wall  14  by the dimples  50  effectively inhibits rotation of the attachment  16  relative to the wall  14 . See FIGS. 7,  9 , and  10 . The dimples  50  also help to hold the edges of the wall  14  around the opening  38  in place and prevent stretching of the wall material. 
     One of the ring members  18 ,  20  has a plurality of fins  42  extending chordwise across its axial center opening  22 ,  32  to form a louvered opening. The fins  42  are preferably slanted to form an acute angle with the axial direction, as best seen in FIG.  4 . When in use, the attachment is preferably placed in the use orientation illustrated in the drawings in which each fin  42  slants downwardly and axially outwardly from an inner portion of the attachment  16 . As used herein, the terms “inner”, “outer”, and the like refer to portions of the attachment  16  that are closer (inner) or farther away from (outer) the wall  14  in which the attachment  16  is installed. 
     The attachment  16  includes a plurality of ribs  44  that are perpendicular to the fins  42 . The ribs  44  extend between and interconnect each pair of adjacent fins  42  to strengthen the fins  42 . Preferably, each rib  44  connects a mid portion of a lower surface of a first fin  42  and a mid inner portion of an adjacent upper surface of a second fin  42 . This leaves an outer portion  46  of the upper surface of the second fin  42  free from connection to the rib  44 , as illustrated in FIG.  6 . As described above, the resulting configuration tends to direct flow of air around the ribs  44  and on through the center openings  22 ,  32  of the attachment  16  along the upper surface of the second fin  42  adjacent to the rib  44 . This helps to ensure that the presence of the ribs does not impede the venting action of the attachment  16 . 
     Air flow passageways are formed between adjacent fins  42 . This is perhaps best illustrated in FIGS. 6 and 8. If it is desired to exclude insects without impeding the venting action, the attachment  16  may be provided with a screen  48 . The screen  48  may be carried by either one of the two ring members  18 ,  20 . In the illustrated preferred embodiment the screen  48  is carried by the first ring member  18  and covers the center opening  22  of the ring member  18 . The screen  48  is positioned inwardly of the fins  42 . 
     The attachment  16  has a thin, flat configuration so that its presence in a flexible wall is unobtrusive and does not interfere with activity nearby. It is anticipated that the attachment will have about the size shown in FIG.  4 . However, the size can be varied. The illustrated embodiment is about one-half thick excluding the projecting portions of the fins  42 . It can be used in a flexible wall that is rolled or folded for storage when not in use. An example of such a wall is a wall of a tent. 
     Each of the ring members  18 ,  20  can be formed in various ways. The preferable method for forming the ring members  18 ,  20  is by injection molding. Preferably, the ring member  18  and the louvers  42  are integrally formed by injection molding. In the illustrated preferred embodiment, the ring members  18 ,  20  have the same outside diameter and, in use, appear to also have the same inside diameter. When the nipple  24  is extending into the center opening  32  of the ring member  20 , the inner diameter of the center opening  22  in the first ring member  18  appears to be the diameter of the assembled attachment  16 . The overall structure of the attachment  16  lends it an attractive appearance from either side of the wall  14  and when viewed through the wall  14 . 
     Although the preferred embodiment of the invention has been illustrated and described herein, it is intended to be understood by those skilled in the art that various modifications and omissions in form and detail may be made without departing from the spirit and scope of the invention as defined by the following claims.