Abstract:
A vent stop is installed into a window/door to limit travel therein of a sash member, and being particularly adapted to permit ease of its installation, especially into a wooden door/window. The stop incorporates multiple retention features to inhibit the stop&#39;s removal, once properly installed. The retention features include a wedge-shaped protrusion located at a distal end of the stop housing, which engages the wood of the window opening when pivotally installed therein, to secure a first end of the stop. The opposite end of the stop may be redundantly secured. A first feature for securing the opposite end may comprise one or more arcuate flanges on housing side walls, flanges being adapted to unidirectional movement so as to permit its movement relative to the window opening during installation, but thereafter deterring counter-pivotal motion that would allow removal of the vent stop. A second feature comprises a deformable spring clip.

Description:
CROSS REFERENCES TO RELATED APPLICATIONS 
     This application claims priority on U.S. Provisional Application Ser. No. 61/273,131 filed on Jul. 30, 2009, the disclosures of which are incorporated herein by reference. 
     This application is a continuation-in-part of U.S. application Ser. No. 12/802,640, filed Jun. 10, 2010, the disclosures of which are incorporated herein by reference. 
    
    
     FIELD OF THE INVENTION 
     The present invention relates to improvements in window vent stops particularly for double hung windows and the like, and to improvements in their installation and operation in preventing a window or door from opening more than a desired amount. 
     BACKGROUND OF THE INVENTION 
     Vent stops are used to restrict the opening of windows and doors, and are primarily used on double hung windows and sliding doors where a sliding sash window or door member slides from a first position to a second position. The vent stop prevents the sash from moving past a selected point, but generally permits the window to be opened a certain amount for ventilation or other purposes. For example, a window vent stop may permit a sash window to be opened four or five inches to allow air circulation, which only constitutes a portion of the window&#39;s normal travel stroke in moving from a fully closed position to a full open position. One of the considerations leading to the use of such vent stops is security concerns relating to unauthorized entry from unlocked and otherwise unprotected doors and windows. 
     Such door and window vent stops are typically adapted to permit installation through an opening into a hollow area of a sash member or window frame, where it is retained therein using a top plate and flexible mounting clips, such as the mounting clips  14  shown by U.S. Pat. No. 5,575,116 to Carlson for a “Window Vent Stop.” Such clips are limiting in that they are not functional for a window that does not have a hollow frame, which may include new wood windows, and also many older windows already in service in building, into which a stop may be desirably installed. 
     The vent stop of the current invention incorporates unique retention means which permit it to be installed into windows that do not have hollow frames, and thus permit retrofit installation of the stop into older windows, and particularly wood windows. 
     OBJECTS OF THE INVENTION 
     It is an object of the invention to provide a vent stop that is easily installed into a new window currently being assembled. 
     It is another object of the invention to provide a vent stop that is easily installed into an older window that is still in service in a building or structure. 
     It is a further object of the invention to provide a vent stop that does not require mechanical fasteners such as screws, for its installation. 
     It is another object of the invention to provide a vent stop that resists removal from a window once installed therein. 
     It is also an object of the invention to provide a vent stop with multiple means of retention within an opening of a window to retain the stop therein. 
     Further objects and advantages of the invention will become apparent from the following description and claims, and from the accompanying drawings. 
     SUMMARY OF THE INVENTION 
     A vent stop is commonly installed into windows and doors to limit travel therein of a sash member. The vent stop, as is common in the prior art, may include a tumbler that may have a first end and a second end, with the tumbler being pivotally mounted to the housing using pin, so as to be pivotable between a retracted position, wherein the tumbler is at least partially disposed within the housing cavity, and an extended position, wherein at least a portion of the tumbler second end is protruding out the opening of the top plate of the housing. A biasing member biases the tumbler to pivot outward from the housing into the extended position. When the tumbler is in the extended position, a portion of the tumbler second end limits movement of a sliding sash of the door or window, but it permits free sash movement when the tumbler is in the retracted position. 
     The vent stop disclosed herein is particularly adapted to permit ease of its installation, especially into a wooden door/window, whether for concurrent installation into newly manufactured window, or for retrofit into an older window still in service in a building or structure. The vent stop incorporates multiple retention means to inhibit the stop&#39;s removal, once properly installed in the window opening, and installation which requires no additional fasteners, such as screws or bolts. The retention means includes a wedge-shaped protrusion located at a distal end of the vent stop housing, which engages the wood of the window opening when pivotally installed therein, to secure a first end of the stop. The opposite end of the stop may be redundantly secured. A first means of securing the opposite end may comprise one or more arcuate flanges on housing side walls. These arcuate flanges may be adapted to unidirectional movement so as to permit its movement relative to the window opening during pivotal installation of the stop, but thereafter deterring counter-pivotal motion that would allow deliberate or inadvertent removal of the vent stop. 
     A second means of securing the opposite end of the stop comprises a deformable spring clip. The spring clip may be integral to the housing or be a separate part that is secured to the housing. The spring clip is adapted to deflect during installation of the stop, with teeth on the protruding end of the spring clip being biased to engage the wood of the opening during the final steps of the installation. The teeth and the biasing of the spring clip serve to jointly ensure that attempted removal of the vent stop, produces a comparable resistance to such removal forces. A block-shaped protrusion on the housing first end ensures a tight fit—possibly an interference fit—between the vent stop and the window opening. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  is a perspective view of one embodiment of the vent stop of the present invention. 
         FIG. 2  is a side view of the vent stop of  FIG. 1 . 
         FIG. 3  is a top view of the vent stop of  FIG. 1 . 
         FIG. 4  is an end view of the vent stop of  FIG. 1 . 
         FIG. 5  is an end view of an alternative embodiment of the stop of  FIG. 1 , being without use of the spring clip. 
         FIG. 6  is an end view of an alternative embodiment of the stop of  FIG. 1 , having only one protruding arcuate flange and being without use of the spring clip. 
         FIG. 7  is an end view of an alternative embodiment of the vent stop of  FIG. 1 , without the arcuate protruding flanges. 
         FIG. 8  is an enlarged end view of the stop of  FIG. 1 . 
         FIG. 8A  is a detail view of the unidirectional feature of the arcuate flanges. 
         FIG. 9  is an exploded view of the parts of the vent stop of  FIG. 1 . 
         FIG. 10  is a perspective view of the vent stop of  FIG. 1 , with the indicator shown detached from the tumbler. 
         FIGS. 11-11   e  are an enlarged side view of the stop of  FIG. 1 . 
         FIGS. 12 and 12   a  are a cross-section of the stop of  FIG. 1 . 
         FIG. 13  is a perspective view of the vent stop of  FIG. 1  ready to be installed into a slot of a window or door. 
         FIG. 14  is the perspective view of  FIG. 13 , with the stop being rotated into the slot of the window. 
         FIG. 14A  is the perspective view of  FIG. 14  with the window/door being cut away to expose the stop. 
         FIG. 15  is a side cross-sectional view of the stop being rotated into the slot of the window, with the spring clip contacting the face of the window, prior to deformation. 
         FIG. 16  is the side cross-sectional view of  FIG. 15 , with the stop being further rotated into the slot of the window, and with the spring clip deforming as it enters the slot of the window. 
         FIG. 17  is the side cross-sectional view of  FIG. 17 , with the stop fully installed into the slot of the window, and with the spring clip engaging the material of the slot of the window. 
         FIG. 18  is the side cross-sectional view of  FIG. 17 , with the stop fully installed into the slot of the window, and with the tumbler in the extended position to prevent movement of a sliding sash, with a reaction to the force of the sash member being provided by the face plate and protrusion. 
         FIGS. 19A-19C  comprise the installation steps of  FIGS. 15 ,  16 , and  17  shown in sequence on the same drawing sheet. 
         FIG. 20  is a descriptive geometric view usable to relate the height, width, and radius dimension of an arc-segment, with the shown equation. 
     
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
       FIG. 1  shows a first embodiment of the vent stop  10  of the present invention. As seen in the exploded view of  FIG. 9 , the vent stop  10  may include a housing  20 , a tumbler  50 , a biasing member  70 , a spring clip  80 , a pin  90 , and an indicator signal member  95 . The tumbler  50  may be pivotally mounted to the housing  20  using pin  90 , and be biased outward from a retracted position ( FIG. 17 ) within a housing cavity into an extended position ( FIG. 18 ). 
     The housing  20  contains several features which are critical to the vent stop  10  of the current invention, which may function similar to other vent stops, but is particularly adapted for ease of installation into, and retention within a window, because of those housing features. Although the housing features make it particularly well suited for installation into a window made of wood, it may nonetheless be suitable for installation into windows made of other materials. 
     The housing  20 , as seen in  FIGS. 11 and 11C , may comprise a top plate  21  with an opening  21 P therein, and one or more housing walls. The top plate  21  may comprise a top surface  22 , a bottom surface  23 , and a peripheral edge surface  24 . The intersection of the top surface  22  with the peripheral edge surface  23  may be broken using a radiused surface  25 . The one or more housing walls may extend away from the bottom surface  23  of the top plate  21 , to a distal end  26 , and may be generally orthogonal to the top plate  21 . The one or more housing walls may comprise a first side wall  27 , a second side wall  28 , a first end wall  29 , and a second end wall  30 . These side walls and end walls may be joined together using adhesive or mechanical fasteners, including, but not limited to, screws, and nuts and bolts, or may be welded together. In addition, the first and second end walls,  29  and  30 , and the first and second side walls,  27  and  28 , may all be formed in a manner so as to be a single continuous wall. 
     A single continuous wall may be the result of forming the housing  20  as a plastic, injection molded part, or as a metallic casting or a forged part, etc. In an embodiment where the housing walls are integrally formed, they may preferably be formed so as to have a first and a second generally flat side wall portion, and to have two semi-circular end wall portions to create a racetrack shape. Whether formed as separate wall members  27 - 30 , or as a unitary wall member, the cross-section of the housing may resemble a race-track shape with an opening  33  therein to form a housing cavity  32 , which may be coterminous with the faceplate opening  21 P, as seen in  FIG. 1 , and  FIGS. 11C and 11D . The distal end  26  of the housing walls may be supported and closed off by a bottom wall  31 . It should be pointed out that the housing walls need not comprise a race-track shaped cross-section, and may alternatively comprise a rectangular cross-section, or other cross-sectional shape. 
     The second end wall  30 , to accommodate installation of the vent stop in a window/door opening, as will be discussed hereinafter, may initially protrude orthogonally from the bottom surface  23  of the top plate  21 , and thereafter transition into a curved portion to form part of a torus  30 T. In a profile view of the second end wall  30 , it may be seen that the curved shape  30 T of the end wall  30  comprises an arc-segment having a radius R wall  that may have an origin  34  proximate to the first end of the housing, and may preferably be at the extreme end of the top plate  21  at bottom surface  23 . Such an origin location may assist in the installation of the vent stop, as will be discussed in the following paragraphs. 
     The vent stop  10  of the current invention may be retained within an opening of a window utilizing any one of, a combination of, or all of, the following retention means. The first end wall  29  may comprise a protrusion  35 . Protrusion  35  may be wedge-shaped by having a top surface  35 T and bottom surface  35 B which converge into a knife-edge, or they may converge to terminate in an end surface  35 E. The purpose of protrusion  35  is to serve as a housing member capable of being driven into the material of the window, when the vent stop  10  is installed into an opening therein. The protrusion  35  may be attached to the housing end wall  29 , or be integrally formed with the first end wall  29 . The protrusion  35  may work in conjunction with either of, or both of, the spring clip  80  or/and the arcuate flanges that protrude from the housing side wall portions  27  and  28 . The protrusion  35  may preferably be located proximate to the distal end  26  of the first wall  29 , to better facilitate the pivotal installation of the vent stop, which is discussed later. 
     The housing side walls (or side wall portions)  27  and  28  may comprise generally planar outside surfaces from which may protrude a flange. As seen in  FIG. 11 , protruding from side wall  27  may be a first flange  36 . Flange  36  may be arcuate, which means to be curved like a bow, or arched. The flange may comprise any appropriate curvilinear shape, possibly being elliptical, or possibly having complex curvature. Although it need not necessarily be so, flange  36  may preferably have an inner side  36 I that is formed in the shape of an arc-segment, which may have an origin at point  34 , at the extreme end of the top plate bottom surface, as previously discussed. Even in the case where the inner side  36 I does not comprise an arc-segment, and may, for example, alternatively be elliptical, it may, to aid in installation of the vent, have at least some point on the curved shape having a radius of curvature with its origin located at point  34 . 
     The outer side  36 T of the arcuate flange  36  may be parallel to the inner side  36 I so as to produce a flange having the generally constant thickness T 36 , as seen in  FIG. 11 . It should be pointed out that the inner  36 I and outer surfaces  36 T (formed by R 36I  and R 36T , respectfully) need not necessarily be offset surfaces, and may, as seen in  FIG. 11E , have slightly different origin locations so as to converge and form an arcuate spiked shape  136 . Alternatively, as seen in  FIG. 11E , they may be parallel but may eventually taper to again form a spiked end on flange  137 , which may aid in the installation of the vent stop. Such tapering may only be needed where the thickness and the height of the flanges may be significant in relation to the depth of penetration required by the corresponding opening in the window, and the material type of the window. 
     To engage the material of the window, when installed therein, the flange  36  may comprise a side surface  36 S being adapted to permit, or be disposed toward engaging in, unidirectional motion upon contact with the faying surface (the opening in the window). The meaning of “fay” herein follows the conventional meaning, which is “to join or be fitted closely or tightly.” Therefore the side surface  36 S of the flange  36  and the portion of the window opening it contacts are faying surfaces, and will be fitted closely together, as described later. This disposition toward unidirectional motion may serve to facilitate installation of the vent stop  10  into the window opening, but may also serve to thereafter oppose its removal therefrom. As seen in the end view of  FIG. 8 , and the enlarged detail view of  FIG. 8A , this disposition toward unidirectional motion may be provided by contouring of the flange  36  to create one or more tooth-like members,  39 ,  40 ,  41 ,  42 , etc. 
     The start of the first tooth  39  may begin with an angled edge surface  39 A which transitions into side surface  36 S by a radiused surface  39 R. The end of the tooth may be defined by a generally normal surface  36 N, which terminates on a surface  36 S′ which is generally parallel to the flange side surface  36 S. The surface  36 N need not actually be normal to side surface  36 S, and may be angled to provide some undercut beneath the tooth in order to provide further engagement with the material of the window opening. The surface  36 S′ may be parallel to side surface  36 S, and provides a transition into the successive tooth  40 , which may be similarly formed using an angled surface  40 A and a normal surface  40 N. The successive teeth may or may not also utilize the radiused transition surface, which, in the case of the first tooth  39 , may serve to initially deform or penetrate the material of the window. The total height of the flange  36 , the spacing of the teeth, and the depth of the teeth down to surface  36 S′, and other related parameters may be calibrated to achieve maximum retention within the material that the window is made from. Even where the window is a wood, those parameters may be varied to accommodate harder or softer woods that may be utilized for the window frame. 
     It should also be noted that the successive teeth  40 ,  41 ,  42 , etc., may be progressively taller, meaning that side surface  36 S would be stepped. Those teeth may also be progressively wider, meaning that the radius of the outer surface, R 36T , may become progressively larger for successive teeth. Such a progression may help to increase retention as each successive tooth may incrementally need such a size increase to provide the same level of engagement with the wood as the previous tooth. Such incremental changes may be very slight, so as to not be distinctly noticeable to the naked eye. 
     In one embodiment of the invention, there may be a second flange  37  being formed on wall  26 , essentially the same as flange  36 , with side surface  37 S being generally co-planar with surface  36 S, but with the flange  37  being formed by inner and outer surfaces  37 I and  37 T, having smaller radii—R 37I  and R 37T . To work best in conjunction with the wedge-shaped protrusion  35 , the first flange  36 , and the second flange  37  may preferably be formed using sufficiently large radii (R 36I , R 36T , R 37I , and R 37T ) so as to have the flanges  36  and  37  located proximate to the housing second end  20 B, but spaced slightly apart from each other. In another embodiment, a third flange  38  may be formed using radii (R 38I  and R 38T ) so as to locate the flange  38  to be closer to the housing first end  20 A. The flange  38  may or may not comprise teeth. Lastly, in another embodiment, the other side wall  28  may also be formed with flange  43 , with it being comparable to flange  36 , and having a unidirectional side surface  43 S. In addition wall  28  may also be formed with flanges  44  and  45  ( FIGS. 4 and 11A ), being comparable to flanges  37 - 38 . Those flanges  44 - 45  may similarly have a unidirectional side surface, which may be generally coplanar with side surface  43 S. Flanges  36 - 38  on wall  27  and flanges  43 - 45  on wall  28  may be formed so as to be symmetric with each other about the mid-plane of the vent stop, which may be shown in  FIG. 11C  by the cutting plane represented by the section arrows therein for  FIG. 12 . This would result in the flanges  43 - 45  being mirror-image copies of the flanges  36 - 38 . Having flanges on both side walls  27  and  28  may better serve to retain the stop within the window opening, as well as to better facilitate the vent stop installation therein. 
     As seen in  FIG. 2 , and the cross-sectional view in  FIG. 12 , the housing second end  30  may comprise a protrusion in the form of a spring clip  80 . Spring clip  80  may be integrally formed with the housing, or, as seen in  FIG. 9 , the spring clip  80  may be a separate part and may be comprised of a series of turns to form an S-shape, and may be inserted into opening  49  in the housing, and be retained therein by a flange  84  of the spring clip contacting an interior housing wall. Spring clip  80  may preferably be formed of a suitably flexible material, including, but not limited to, aluminum, chrome vanadium, and stainless steel. The physical proportions of the spring clip  80  may be such that they permit the spring clip to be deformed during its installation, but nonetheless provide sufficient biasing to engage the material of the window once installed into the opening therein. 
     The portion of spring clip  80  that may protrude from the housing  20  may preferably be curved, and may be so curved so as to take a circular shape  81  ( FIG. 9 ). The circular shape  81  may transition into a straight portion  82 . The straight portion  82  may terminate in a protruding end that may comprise one or more teeth  83 . The teeth  83  may serve to better enable the spring clip, in conjunction with the biasing produced through its construction, to engage the material of the window to better retain the vent stop within the window opening. The behavior of the spring clip is best discussed in terms of the overall installation of the vent stop  10 . 
     As seen in  FIG. 13 , the vent stop  10  may be installed into an opening  102  in a window  101 , where the opening  102  may be on the master window frame, or, in the case of double-hung sash windows, the opening may be in one of the sliding sash members to inhibit travel of the other sash member. The opening  102  may be a race-track shaped opening, or it could simply be a rectangular-shaped opening, but in either case, the cross-section of the opening may preferably match the cross-sectional shape of the features of the housing  20  of vent stop  10 . The size of the opening  102  will necessarily be smaller than the periphery  24  of the top plate  21 , but must be coordinated with the extent of the retention means of the housing, as discussed in the following paragraphs. 
     The vent stop  10  may be inserted into the opening  102  at an angle, with a portion of the housing first end  20 A being positioned to first enter the opening  102  proximate to the first end  103  of the opening. The housing first end  20 A may be inserted such that point  34  ( FIG. 11 ) on the bottom surface  23  of the top plate  21  contacts the face of the window frame or sash member, as seen in  FIGS. 14 ,  15 , and  19 A. The vent stop  10  may rotate freely until the protruding end of spring clip  80  approaches the second end  104  of opening  102 , or until the teeth of the arcuate flanges  36 - 38  and  43 - 45  begin to contact the sides  105  and  106  of the opening  102 . Applying a force to the top plate  21  ( FIG. 15 ) at the housing second end  20 B may then cause the end surface  35 E of the wedge-shape protrusion  35  to engage the material of window  101 , and become embedded therein, and may also cause the beginning of the unidirectional engagement of the arcuate flanges  36 - 38  and  43 - 45  with the cavity side surfaces  105  and  106  of opening  102 . However, if flanges  36 - 37  and  43 - 44  comprise an arc segment having a sufficiently large width (Note, radius equation: R=H/2+W 2 /8H, see  FIG. 20 ), so that they cover most of the walls  27  and  28  to reach most of the way to bottom wall  31 , the flanges may engage the opening  102  prior to the wedge-shaped protrusion  35  engaging the material of the window. The width of the arc-segment of flanges  36 - 37  and  43 - 44  and the extent of wedge-shaped protrusion  35  protruding from wall  29  may be coordinated in size to simultaneously engage the window, as the vent stop is pivoted during installation. 
     As the spring clip  80  contacts the window  101 , continued application of the force to the top plate  21  causes further engagement of the wedge-shaped protrusion  35 , as well as deformation of the spring clip  80 . The sequence of steps in the installation of the vent stop  10  is viewable in the views comprising  FIGS. 19A ,  19 B, and  19 C. Deformation of the spring clip  80  may cause it to appear as it does in  FIG. 19B . With continued application of force to the top plate  21  to continue the pivotal installation of vent stop  10 , the housing wall  30  may contact the protruding end of spring clip  80  to drive it into the second end  104  of opening  101 , so that the teeth  83  of said protruding end of the spring clip  80  engage material of the window. The biasing of the spring clip  80  may be sufficient by itself to engage the material of the window, particularly where the window is made of wood. In an alternative embodiment, the protruding portion of spring clip  80 , when deflected upon installation, may fall short of reaching the housing wall  30 , so that as the vent stop  10  is pivoted, the angled portion  30 A of the housing wall  30  may serve to shoe-horn the stop into the opening  102 . In this case, the biasing of the spring clip  80  would independently serve to cause its engagement with the window opening  102 . 
     This engagement of the spring clip  80 , as positioned in  FIG. 19C , may be slightly exaggerated. However, attempts to counter-rotate the vent stop  10 , to initiate its removal from the window, would result in driving the teeth  83  of the spring clip  80  further into the window, as seen in the figure, and thus serves to help anchor the vent stop once fully installed in the opening. The vent stop  10  is fully installed in the window opening  102  when the top plate  21  at the housing second end  20 B comes in contact with the window ( FIG. 19C ) face. By the time the top plate  21  at the housing second end  20 B makes contact with the window, another protrusion protruding from the housing first end wall  29 , which may preferably be block-shaped protrusion  46 , may also contact the end surface  103  of the window opening  102 . The block-shaped protrusion  46  may preferably be located between the top plate  21  and the wedge-shaped protrusion  35 . 
     It is important to note the coordination between the size of the opening  102  in the window  101 , and the extent of the vent stop  10  in both principal directions—side-to-side and end-to-end. The distance between the face of the block-shaped protrusion  46  and the second end wall  30  (denoted by length dimension  47  in  FIG. 11 ) and the distance between cavity end surfaces  103  and  104  of window opening  102  may be set to create a small interference fit, meaning that the distance between end surface  103  and  104  may be slightly smaller than the length dimension  47 . As such, the block-shaped protrusion  46  may be driven to engage and form an indentation in the window opening, just like the wedge shape protrusion  35 , though to a lesser extent (see  FIG. 19C ). Similarly, the distance between the generally planar surfaces  36 S and  43 S of the vent stop  10  ( FIG. 11A ) and the distance between the cavity side surfaces  105  and  106  of window opening  102  ( FIG. 13 ) may be set to create a small interference fit at installation, meaning that the distance between side surfaces  105  and  106  may be slightly smaller than the distance between the generally planar surfaces  36 S and  43 S. The small interference fit may serve to aid in the unidirectional engagement of the flanges  36 - 37  and  43 - 44  with the window opening. In addition, the window opening  102 , particularly in the case where the window is wooden, may be formed using a manufacturing process that creates side surfaces  105  and  106  having a considerable surface roughness, which may aid in the unidirectional engagement of the flanges, since conversely, a relatively smooth surface finish may serve to counter the unidirectional nature of the arcuate flanges. 
     The tumbler  50  may have a first end and a second end, with the tumbler  50  being pivotally mounted to the housing  20  using pin  90  through in-line orifices  48  in walls  27  and  28  ( FIG. 11 ). Being so mounted, the tumbler  50  may be pivotable between a retracted position ( FIG. 17 ), wherein the tumbler is at least partially disposed within the housing cavity, and an extended position ( FIG. 18 ), wherein at least a portion of the tumbler second end is protruding out the opening  21 P of the top plate  21 . Outward pivotal travel of the tumbler  50  into the extended position may be limited by a stop feature  51  on the tumbler contacting a complementary housing feature ( FIG. 12 ). The biasing member  70  biases the tumbler to pivot outward from said housing into the extended position. When the tumbler  50  is in said extended position, a portion of the tumbler second end limits movement of a sliding sash of the window, but it permits free sash movement when the tumbler  50  is in the retracted position. 
     The vent stop may further comprise a colored signal  95  ( FIGS. 9 and 10 ) which may be a c-shaped member that may attach on to the tumbler. It may snap-on to the tumbler  50 , of be attached using fasteners. The signal  95  may provide indication to a person that the tumbler is in the extended position. 
     The examples and descriptions provided merely illustrate a preferred embodiment of the present invention. Those skilled in the art and having the benefit of the present disclosure will appreciate that further embodiments may be implemented with various changes within the scope of the present invention. Other modifications, substitutions, omissions and changes may be made in the design, size, materials used or proportions, operating conditions, assembly sequence, or arrangement or positioning of elements and members of the preferred embodiment without departing from the spirit of this invention.