Abstract:
A clothes dryer exhaust vent comprises a vent hood and a detachable grill. The detachable grill fits within the vent hood opening. A snap-fit system is provided which allows one to grasp the exposed edges of the grill, squeeze inwardly and readily disengage the grill from the vent hood. This system avoids having to unscrew the grill, remove the clips or the like to provide for grill service.

Description:
FIELD OF THE INVENTION 
     This invention relates to a clothes dryer vent which is particularly suited to venting the dryer exhaust outdoors while preventing animals from entering the vent. 
     BACKGROUND OF THE INVENTION 
     Exhaust vents have been provided for dryers for several years. Commonly, the exhaust vent includes a type of flapper valve which prevents cold air or hot air from entering the house through the dryer vent. An example of a dryer vent with flapper valve is described in U.S. Pat. No. 4,967,490. However, with the exterior vent animals can still enter the vent area and nest in those areas. U.S. Pat. No. 5,547,422 describes a cage-like guard which may be placed over the vent to preclude animals from entering the vent and nesting in the vent opening. However that system is quite bulky and can be damaged since it is mounted on the exterior of the home. 
     Protective grills or screens have been mounted in the exhaust vent, such as described in Canadian patent 2,111,157 and U.S. Pat. No. 5,046,408. The protective screens are clip-mounted in the vent or mounted in narrow channels. These arrangements are cumbersome and usually break-down resulting in animals gaining access to the interior of the vent opening. 
     An attempt to overcome these problems has been provided with snap-fit type grills; for example, as described in Canadian patent application 2,232,659 and U.S. Pat. Nos. 5,722,181 and 5,916,023. Various arrangements are provided in snap-fitting the grill in place. In U.S. Pat. No. 5,722,181, the entire grill is snap-fitted to a base. However, it projects considerably from the exterior wall and can be readily knocked off. The grill of U.S. Pat. No. 5,916,023 is mounted at the base of the vent opening. However it is very difficult to remove from the exhaust vent hood, because the snap-fit projections engage the front wall of the hood. One has to use a screwdriver or the like to unclip the grill from the hood. This can result in breakage of the grill particularly at colder temperatures. The hinge-mounted grill, as described in Canadian patent application 2,232,659 is pivoted at its base and clips into the hood at its top. Again, particularly in cold weather, it is particularly difficult to disengage the grill. Normally a screwdriver is required to pry it out. When the grill falls down, it can be readily disengaged from its hinge connections which can result in breakage of the unit. 
     Applicant&#39;s invention overcomes a number of the above problems by providing a grill which is snap-fitted into a downwardly projecting opening of the vent hood, The grill interfits with the hood in a way that it can only be mounted in one direction in the hood. It can only be disengaged by squeezing the grill at its sides and thirdly, the detent system is arranged where such gentle squeezing of the grill provides for immediate disengagement of the grill from the hood. 
     SUMMARY OF THE INVENTION 
     In accordance with an aspect of the invention, a cloths dryer exhaust vent comprises: 
     i) a vent hood having a rear wall for attachment to a building exterior wall and defining a downwardly projecting rectangular shaped vent opening, the opening being defined in part by a reinforcing flange about hood opening perimeter, the flange having an interior surface about three sides of the opening, the fourth side of the opening being defined by the rear wall, the flange interior having on opposing interior sides stops and detent projections, the rear wall defining said fourth side of the opening and having a downwardly extending ridge, 
     ii) a detachable grill for the vent hood opening which snap fits into the opening by engaging the interior surface of therein forcing flange, the grill having a three sided perimeter lip for fitment within the reinforcing flange, the fourth side of the grill having a depending lip for mating fit over the ridge of the rear wall, the grill having on opposing lip portion recesses for receiving the detent projections of the hood, the opposing lip portions having rear edges which engage the stops of the hood, the stops being positioned on the hood reinforcing flanges to locate the grill recesses to snap fit with the detents and provide for portions of the grill opposing lips to project outwardly of the hood flange, the outwardly projecting lip portions providing finger grip sections to permit grasping the grill opposing walls and by gentle inward pressure disengage the grill from the hood for cleaning, the grill depending lip matingly engaging the hood ridge providing for one-way fitment of the grill on reinstallation to the hood. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     Preferred embodiments of the invention are shown in the drawings; wherein: 
     FIG. 1 is an exploded perspective view of the clothes dryer exhaust vent of this invention; 
     FIG. 2 is a section through the exploded view of FIG. 1; 
     FIG. 3 is a section through the assembled vent hood of FIG. 1; 
     FIG. 4 is a top section of the grill to be mounted to the hood; 
     FIG. 5 shows the detent system engaged for fitting the grill to the hood; and 
     FIG. 6 shows the application of gentle pressure to disengage the detent system of FIG.  5 . 
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS 
     The clothes dryer exhaust vent of this invention provides a readily disconnectable grill which permits easy cleaning regardless of the outdoor temperatures. At the same time, the grill is not accessible and cannot become easily dislodged from the vent hood. The vent hood and grill have interfitting portions which ensure one way fitment of the grill to the hood. Such mating of the grill with the hood also directs a user to grasp the correct sides of the grill to disengage it from the hood. 
     With reference to FIGS. 1 and 2, the clothes dryer exhaust vent  10  comprises a hood  12  and a grill  14 . The hood  12  has a rear wall generally designated  16  with a dryer exhaust vent ducting  18  connected or integrally formed therewith. The vent hood has a cover  20  integral with the rear wall  16 . The vent hood  12  has a downwardly projecting opening  22 . The opening is defined in part by a reinforcing flange  24  which has three wall portions  26 ,  28 , and  30 . The fourth side of the opening is defined by the rearwall  16  having a ridge portion  32 . The reinforced flange has three separate stops  34 ,  36  and  38 . In addition, the reinforced flange has opposing detent projections  40  and  42 . The vent hood  12 , as it is integral with the rearwall  16 , has side portions  44  and  46  as well as front slopping portion  48 . The rearwall includes rounded side members  50  and  52  which carry holes  54  to permit fastening of the hood rearwall and hence the hood assembly to an exterior building wall. The rearwall  16  is also equipped with a duct mounting flange  56  which is of a diameter to receive dryer exhaust vent ducting  18 . 
     The grill  14  comprises a screen generally designated  58  which is integral with three sidewalls  60 ,  62  and  64 . The bottom part of the grill is defined by a depending lip  66  which, in accordance with this particular embodiment, is curved to mate with the curved outer surface  68  of the ridge  32 . The lip portions  60  and  64  carry recesses  70  and  72  which engage the respective detent projections  40  and  42  when the grill is snap-fitted in place on the vent hood. As shown in FIG. 2, the grill  14  is advanced in the direction of arrow  74  for interfitment within the vent hood. As shown in FIG. 3, the grill is assembled to the vent hood where the respective stops  34 ,  36  and  38  limit the extent of travel of the grill  14  into the vent hood opening  22 , but at the same time, allows sufficient travel of the grill lips into the vent opening so that the recesses  70  and  72  engage the detent projections  40  and  42 . Also as shown in FIG. 3, the curved lip  66  matingly engages the correspondingly curved ridge  32  to provide for the one-way orientation of the grill  14  on assembly to the hood. 
     As shown in FIG. 4, the grill  14 , as it is advanced towards the hood  12 , engages the respective detents  40  and  42  where the stops  34  and  38  limit further inward travel in the direction of arrow  76 . It is appreciated from FIG. 4 that the reinforcing flange  24  is considerably thicker than the balance of the wall portion  78  of the hood. This reinforcing flange prevents the hood from expanding and in turn forces the grill lips  60  and  64  to deform inwardly when the grill is snap fitted to the hood. 
     As shown in FIG. 5, the respective detents  40  and  42  carry rounded, sloped portions  80  which act as cams to urge the respective grill lips  60  and  64  inwardly when fitting the grill to the hood. The leading edge  82  of the grill engages the sloping portion  80  of the detent to urge the respective lip inwardly. For disassembly, one simply squeezes on the exposed portions  84  of the opposing grill lips  60  and  64 . This is shown in more detail in FIG. 6. A gentle squeezing action in the direction of arrows  86  disengage the recess  72  from the detent  42 . A similar action occurs with respect to recess  70  disenganging from detent  40 . As a result, the edge  88  of the recess  72  clears the internal face  90  of the detent projection  42  to permit removal of the grill from the hood in the direction of arrow  92 . The spacing of the stop  38 , for example, relative to the leading edge  94  of the grill provides for a slight spacing  96  to permit clearing the edge  94  relative to the stop  38  so that the surfaces do not bind. Hence by way of a gently squeezing action, the grill can be disengaged and removed from the vent hood for service. 
     There are many significant advantages and features which flow from this type of dryer exhaust vent hood design. The one-way orientation for the grill ensures that the grill is properly installed in the vent hood. Furthermore, the one-way orientation ensures that the user squeezes on the correct sides of the grill. Any attempt to squeeze the curved lower lip  66  will not work because due to the inherent curved nature of the lip, there is extra reinforcement and the grill will not distort in that direction. Suitable printing may be placed on the surface  48  of the hood, directing the consumer to squeeze gently on the edges of the grill; namely lips  60  and  64  to disengage the grill. This facilitates grill removal without having to bent down or kneel down to look under the vent hood. One may simply reach under the vent opening, squeeze the grill lips and disengage the grill form the hood for easy cleaning. Correspondingly, when it is desired to fit the grill back in place, the one-way orientation ensures that the detents line up with the recesses and a proper snap-fitting of the grill back into the hood is achieved. This ensures that the grill is properly fitted into place and avoids any accidental removal of the grill from the hood. 
     The significantly reinforced perimeter of the hood also ensures that, if one accidentally grasps the hood perimeter, it will not readily squeeze so that the consumer knows that they need to regrip the grill and squeeze it gently for removal. Furthermore, in squeezing the grill lip for removal, the reinforced hood portion will not follow the grill, so that disengagement is ensured. By following the grill, it is meant that there is some friction fitting of the grill to the hood and by squeezing the grill lips inwardly, the reinforced portions of the hood prevent the sides of the hood moving with the grill and instead by pulling on the grill, the frictional engagement is overcome to allow disengagement of the grill from the hood. 
     Although preferred embodiments of the invention have been described herein in detail, it will be understood by those skilled in the art that variations may be made thereto without departing the spirit of the invention or the scope of the appended claims.