Abstract:
Structure for maintaining a sliding window sash at an intended position with respect to a frame within which the sash moves. The structure serves to retain the sash at a position along an axis generally perpendicular to a plane defined by the window frame. An inwardly facing surface of the frame has formed therein an elongated trough which extends generally parallel to a direction of intended sliding movement of the sash. A blade is mounted within a cavity in the sash and disposed for pivotal movement between a first position, wherein the blade is retracted within an outwardly facing surface of the sash, and a second position, wherein the blade is extended through the outwardly facing surface of the sash into the trough defined within the inwardly facing surface of the frame. The blade is normally biased to the second position, but it can volitionally be retracted to the first position to enable tilting inward or removal of the sash from the window frame.

Description:
RELATED APPLICATIONS 
   This application is a continuation under 37 C.F.R. 1.53(b) of U.S. application Ser. No. 09/703,533 filed Nov. 1, 2000 (now U.S. Pat. No. 6,672,009), which is a continuation of U.S. application Ser. No. 09/328,085 filed Jun. 8, 1999 (now U.S. Pat. No. 6,141,913), the specifications of which are incorporated herein by reference. 

   TECHNICAL FIELD 
   The present invention deals broadly with the field of windows. More specifically, however, the invention applies to a window, such as double-hung window, wherein a sash slides within a frame. The specific focus of the invention is structure employed to effect retention of the window sash within the frame at an intended location along an axis perpendicular to a plane defined by the window frame within which the sash slides. 
   BACKGROUND OF THE INVENTION 
   The prior art includes many types of windows which are employed to bring light into a building. One type of window known in the prior art is a double-hung window. Such a window typically employs two vertically movable sash assemblies, each carrying its own pane of glass, which are movable, typically, vertically within the frame. 
   Opposed, inwardly facing lateral portions of the frame are typically provided with a balance tube which includes appropriate structure to render the window sashes more safe. Balance mechanisms are employed within the balance tube in order to deter undesirable, unintended slamming of a sash such that injury could result. 
   It is also desirable, however, that the sashes be able to be tilted inward or removed for cleaning of the glass portions of the sash assemblies. Various mechanisms have been employed to release a sash from a position which it is intended to occupy within the frame. Typically, a sash is desired to be located at a position along an axis, generally perpendicular to a plane defined by the frame, for sliding movement along that position. Various types of structures have been utilized to effect maintenance of a sash in the desired position yet allow it to be tilted inward or removed for cleaning. One such structure utilizes a pair of laterally extending latch mechanisms carried by the sash. The latch mechanisms move linearly along an axis through the sash and into the frame. One latch mechanism extends laterally on one side of the sash and a second latch mechanism extends laterally on the other side of the sash. When it is desired to remove a sash, the sash is moved to an intended vertical release location, and the person removing the sash releases one latch with one hand and the other latch with the other hand. The sash is then tilted or slid out of its normal position and removed from the frame for cleaning. Such a structure has a number of drawbacks. One is that the person removing the window sash needs full availability of both hands to effect release of the latches. Attempts have been made to solve this problem by designing a unitary assembly for concurrently releasing both latches (that is, for simultaneously effecting retraction of the latches). While some measure of success has been achieved with these attempts, other problems still exist. For example, linearly moving latches typically do not provide fully adequate definition of structure for sliding of a sash along an intended track and adequate resistance to pressures which might tend to dislodge a sash from the window frame. One reason for the inadequate resistance to dislodgement is the relatively small cross-section of a latch mechanism extending from the sash. 
   It is to these dictates and shortcomings of the prior art that the present invention is directed. It is a position maintenance mechanism which addresses these dictates and problems and provides solutions which make the invention a significant over prior art apparatuses. 
   SUMMARY OF THE INVENTION 
   The present invention is apparatus which functions to maintain a sliding window sash at an intended position along an axis which is generally perpendicular to a plane defined by a frame within which the sash slides. The frame has an inwardly facing surface which, when the sash is in an intended position at which it slides within the frame, is Opposite an outwardly facing surface of the sash. The apparatus in order to maintain the sash at such an intended position includes means to define an elongated trough formed in the inwardly facing surface of the frame. The trough extends generally parallel to the plane defined by the frame and generally in the direction of intended sliding of the sash. The apparatus further includes a blade which defines a plane and means to mount the blade within a cavity in the sash. The blade is mounted and oriented with the plane defined thereby generally parallel to the plane defined by the frame. The blade is disposed within the sash for pivotal movement between a first position and a second position. In the first position of the blade, it is retracted within the outwardly facing surface of the sash and does not extend outwardly beyond the surface of the sash. In its second position, the blade is extended beyond the outwardly facing surface of the sash and into the trough. Means are provided to normally bias the blade to the second position thereof, and means are provided to allow selective retraction of the blade to its first position. 
   It is intended that the blade, when it is in its second position received within the trough, will be extended fully into the trough to engage a bottom thereof. In a preferred embodiment, the bottom of the trough has a slot formed therein. The location of the slot along the bottom of the trough is such that, when the sash is in a closed position, the blade is at a position coextensive with the slot and extends into the slot. The pivotal disposition of the blade wherein it is extended into and through the slot in the bottom of the trough is defined as a third position of the blade. 
   In the preferred embodiment, the blade includes an edge which is angled such that, as the sash is moved from a closed position to an open position, the angled edge engages an end of the slot and ramps the blade up and out of the slot. Such action facilitates retraction of the blade from its third position to its second position. 
   The blade is disposed for pivoting about an axis which is generally perpendicular to the plane defined by the window frame. It is envisioned that a coil spring would be employed to bias the blade about such an axis outwardly through, and away from, the outwardly facing surface of the sash to its second and third positions. 
   The preferred embodiment contemplates employment of a linearly moving actuator to effect retraction of the blade within the outwardly facing surface of the sash. Such an actuator would be operatively connected to the blade to overcome the biasing of the blade to its second and third positions, and would effect rotation of the blade in a direction opposite that in which the coil spring biases the blade. 
   A preferred embodiment of the invention includes a wire yolk which is attached to the blade and a length of cord which is attached to the yolk. The cord extends away from the yolk and is attached to a driver for drawing the length of cord inwardly with respect to the outwardly facing surface of the sash to effect rotation of the blade against the biasing means. 
   It is envisioned that an end plate assembly would be provided for cooperation with the sash, the end plate assembly including a face plate mounted generally flush with the outwardly facing surface. The end plate assembly would include a pair of generally parallel tabs extending inwardly from the face plate. The tabs, it is intended, would have oppositely facing surfaces, each of these surfaces mounting a stub axle which is substantially coaxial with a stub axle on the facing surface of the other tab. The two-stub axles would extend toward each other so as to be received within an aperture in the blade, the aperture sized and shaped to receive the stub axles. 
   Each of opposite sides of the blade defines a ramp surface. When the blade is inserted between distal ends of the stub axles, the ramp surfaces increasingly urge the distal ends of the stub axles apart until the distal ends become registered with the aperture. They then snap into the aperture to effect mounting of the blade. 
   In practice, a sash configured in accordance with the invention would very likely employ means defining an elongated trough in each of oppositely facing inward surfaces of the frame. Each of said troughs would extend generally parallel to the plane defined by the frame and generally in a direction of intended sliding of the sash. Each of such troughs would be intended to receive one of a pair of blades which define a generally common plane. Each of the pair of blades would be mounted within a corresponding cavity in the sash and oriented with the plane defined by the blades generally parallel to the plane defined by the frame. As in the case of the structure previously described, each blade would be disposed for pivotal movement between a first position, wherein the blade is retracted within a corresponding outwardly facing surface of the sash, and a second position, wherein each of the blades is extended into a corresponding trough in an inwardly facing surface of the frame which is opposite the outwardly facing surface of the sash within which the cavity in which the blade is mounted is formed. The blades would normally be biased to their second positions in engagement with the bottom of the troughs, and means for selectively retracting the blades to their first positions would be provided. 
   With the dual blade embodiment, means would be provided to effect retraction of the blades from their second positions to their first positions simultaneously. The invention envisions a common member for effecting concurrent retraction of the blades. 
   The present invention is thus improved apparatus for mounting and maintaining a sash within a window frame. More specific features and advantages obtained in view of those features will become apparent with reference to the accompanying drawing figures, the DETAILED DESCRIPTION OF THE INVENTION, and appended claims. 

   
     BRIEF DESCRIPTION OF THE DRAWINGS 
       FIG. 1  is a perspective, exploded view of apparatus in accordance with the present invention, window sashes being shown in phantom, and some portions of the structure being broken away; 
       FIG. 2  is a side elevational view of a maintaining blade as mounted within an end plate assembly; 
       FIG. 3  is a top plan view of the end plate assembly without a blade and biasing spring mounted therewithin; 
       FIG. 4  is a first end view of the face plate assembly of  FIG. 3 ; 
       FIG. 5  is a second end view of the face plate assembly of  FIG. 3 ; 
       FIGS. 6 and 7  are bottom sectional views illustrating the mounting of a blade in an end plate assembly; and 
       FIG. 8  is an elevational view of a double hung window system. 
   

   DETAILED DESCRIPTION OF THE INVENTION 
   Referring now to the drawings, wherein like reference numerals denote like elements throughout the several views,  FIG. 1  is an exploded view illustrating dual sashes  10 ,  12  of a double hung window and a blade mechanism  14 , which is intended to be recessed within a cavity  16  in the inner sash  10 . The cavity  16  in the sash  10  is overlain, on a side of the sash, by a face plate  18  mounted generally flush with the outwardly facing side surface  20  of the sash  10 . The face plate  18  is part of an end plate assembly  22  which includes, additionally, a pair of generally parallel tabs  24 ,  24 ′ which extend inwardly from the face plate  18  into the cavity  16 . The end plate assembly  22  also includes a base  26  which functions for an intended purpose as will be discussed hereinafter. 
   The figures illustrate a blade member  14  which is pivotally mounted for rotation about an axis generally transverse to a plane defined by the window sash  10 .  FIGS. 2-7  illustrate the specific structure of the end plate assembly  22  and its cooperation in mounting the blade  14  for rotation. 
     FIG. 1  illustrates a coil spring  28  which is shown as being connectable, at one end thereof, to a hook member  30  of the blade  14 . The other end of the coil spring  28  is connectable to the base  26  of the end plate assembly  22 . The coil spring  28 , thereby, biases the blade  14  for rotation, in a direction as seen in  FIG. 1 , in a clockwise direction. 
   A yoke member  32  is attached to the blade  14  to effect selective overcoming of the bias of the coil spring  28  in order to retract the blade  14  for a purpose discussed hereinafter. The yoke member is illustrated as being constructed of a wire stock formed into a bail, opposite ends of which are passed through an aperture  34  provided in the blade  14 . The bail  32  thereby has an end, proximate the blade  14 , which serves to apply force to the blade  14  in a direction, as viewed in  FIG. 1 , counter clockwise so as to overcome the bias of the coil spring  28 . The wire from which the bail  32  is formed is provided with a narrow neck  36  at an end remote from blade  14 . The neck  36  defines a channel  38  which extends away from the blade  14 , when the bail  32  is connected to the blade  14 , to facilitate connection of an actuator mechanism (not shown). A remote end of the actuator is illustrated in  FIG. 1. A  segment of flexible filament  40  is shown as extending through the narrowed channel  38  formed in the neck  36 , an end of the filament  40  having a sleeve  42  crimped onto the filament  40 . Typically, the sleeve  42  would have a diameter smaller than an expanded channel  44  formed within the bail  32  so that the filament  40  end, with the sleeve  42  crimped thereon, could be slid through the expanded channel  44  and then withdrawn into the narrowed channel  38  which would have a width smaller than the diameter of the sleeve  42 . 
   The overall actuator structure could be constructed in any manner desirable. The actuator would permit volitional rotation of the blade  14  in the counter clockwise direction, as viewed in FIG.  1 . With the embodiment illustrated, it would include means for drawing the filament  40  which in turn would draw the yoke  32  to effect the counter clockwise rotation. It will be understood that any appropriate actuator means, however, could suffice. 
     FIG. 1  also illustrates a portion of a balance tube  46  which defines an elongated trough or track  48  in an inwardly facing surface  50  of the window frame  52 . In double hung window applications, the balance tube  46  employs mechanisms which function to deter undesirable, unintended slamming of a sash where injury could result. 
   The balance tube  46 , in the case of the present invention, includes, defined therein, an elongated trough  48  which faces inwardly. The trough  48  extends generally parallel to a plane defined by the window frame  52 . The trough  48  runs generally in a direction of intended sliding of the sash  10 . 
     FIG. 1  illustrates a slot  54  formed in the balance tube  46  at the bottom of the trough  48 . This slot  54  is formed at a location such that, when the window sash mechanisms are in their closed positions, a corresponding slot  56  in the end plate assembly face plate  18 , through which the blade member  14  can extend, is registered with the slot  54  formed in the balance tube trough  48 . 
   In order to ensure that the slot  56  in the face plate  18  is maintained in the desired position relative to the inner sash  10 , it is secured at a location on the side stile overlying the cavity  16 . Such affixation is typically effected using wood screws  58  as shown. 
     FIG. 2  illustrates the blade  14  mounted in place between the tabs  24 ,  24 ′ extending inwardly into the cavity  16  from the face plate  18 . That figure shows a second position of the blade  14  in solid line and first and third positions of the blade  14  in phantom line. 
   The first position of the blade  14  is such that the blade  14  is retracted within an outwardly facing surface  20  of the sash  10  (that is, recessed within the cavity  16 ). The third position of the blade  14  is one wherein the blade  14  not only extends into the trough  48  engaging the bottom thereof, as it does in its second position, but wherein the blade  14  extends fully to the bottom of the trough  48  and into and through the slot  54  formed in the bottom of the trough  48 . 
   As will be able to be seen, when the blade member  14  is in its second position, it will ride in the trough  48  and facilitate raising and lowering of the window sash  10 . It serves as a track rider which rides on the track defined by trough  48 , and the thickness of the blade member  14  can be made so that there is a minimum, if any, wobble of the sash  10  relative to the window frame  52  of which balance tube  46  is a part. Because of the biasing of the blade  14  to the second position by the coil spring  28 , the blade  14  will tend to remain received within the trough  48  as long as action is not taken to operate the actuator in order to overcome the bias of the spring  28  and cause rotation of the blade  14  to its first position. 
   The bias of the spring  28  is sufficiently strong such that, when the sash  10  is moved to its closed position with the slots in the face plate  56  and bottom of the trough  54  registered, the blade  14  will extend into the slot in the trough  54 . This will effect an even more positive preclusion of movement of the sash  10  in a direction perpendicular to a plane defined by the window frame  52 . The sash  10  will, thereby, be even more securely disposed to deter unwanted removal. 
   As the sash  10  is moved along the track, a ramped edge  60  of the blade  14  will ride over a correspondingly ramped surface  62  of an end of the slot  54  in the bottom of the trough  48 . This will serve to allow the blade  14  to ride up and out of the slot  54  in the trough  48 . Nevertheless, because of the coil spring biasing means  28 , the tip  64  of the blade  14  will still engage the bottom of the trough  48 . 
   As will be able to be seen then, unless some positive action is taken to move the blade  14  in a rotational manner to its first position, the blade  14  will be maintained in either its second or third positions. When it is desired, however, to remove the sash  10  from the window, operation of the actuator means can be initiated to overcome the bias of the coil spring  28  and rotate the blade  14  to its first position. With the blade  14  in this position, there will be no obstruction to rotation of the sash  10  out of its location between the frame  52  or, if desired, removal of the sash  10 . 
     FIGS. 3-5  illustrate the end plate assembly  22  in different views, and  FIGS. 6 and 7  illustrate the assembly  22  in combination with the blade  14 .  FIG. 6  shows the blade in the process of being inserted into position pivotally mounted to tabs  24 ,  24 ′ of end plate assembly  22 .  FIG. 7  shows the blade  14  having been fully inserted between tabs  24 ,  24 ′ with a stub axle  66 ,  66 ′ carried by each of tabs  24 ,  24 ′ snapped into an aperture  68  formed in blade  14 . Aperture  68  defines the axis of rotation of blade  14 . 
   Referring now to  FIGS. 3-5 , end plate assembly  22  includes face plate  18  and tabs  24 ,  24 ′ extending rearwardly therefrom. As previously discussed, tabs  24 ,  24 ′ are spaced from each other, and each tab  24 ,  24 ′ has a stub axle  66 ,  66 ′ extending inwardly from its corresponding tab  24 ,  24 ′ toward the other stub axle. The stub axles  66 ,  66 ′, together, define a shaft about which the blade  14  rotates. 
   Tabs  24 ,  24 ′ are manufactured from a resilient material so that they can be deflected outwardly, as indicated by arrows  70  in  FIG. 6 , to allow introduction of blade  14  therebetween. Blade  14  includes a dual-ramped portion knife edge which serves to urge tabs  24 ,  24 ′ apart as the ramped surfaces of the knife edge engage inwardly-facing surfaces of the stub axles  66 ,  66 ′. Tabs  24 ,  24 ′ will continue to be urged apart as the knife edge is pushed in the direction of arrow  72  as seen in FIG.  6 . Eventually, blade  14  achieves a position as seen in  FIG. 7 , and tabs  24 ,  24 ′ snap inwardly to position stub axles  66 ,  66 ′ within pivot aperture  68  in blade  14 . Blade  14  is then mounted for rotation. 
     FIGS. 1 and 2  illustrate a base  26 , as previously discussed, of end plate assembly  22 . Base  26  includes a rectangular cross-section shaft which is generally parallel to face plate  18 . This rectangular cross-section shaft  74  serves as a point of affixation of one end of coil spring  28 . The other end of coil spring  28  is extended upwardly, through an expanded portion of yoke/bail  32 , and is attached to blade  14  at hook member  30 . As can best be seen in  FIG. 2 , this will effect a clockwise bias on blade  14  in contra-rotation to the force applied to blade  14  by filament  40  extending from the actuator. 
     FIGS. 1 and 2  illustrate end plate assembly  22  as being mounted to inner sash  10  with face plate  18  overlying cavity  16 . Affixation of end plate assembly  22  to sash  10  is shown as being accomplished with a pair of Phillips-head screws  58 . Screws  58  are inserted through aperture  78  in face plate  18  and into sash  10 . 
   It will be understood that this disclosure, in many respects, is only illustrative. Changes may be made in details, particularly in matters of shape, size, material, and arrangement of parts without exceeding the scope of the invention. Accordingly, the scope of the invention is as defined in the language of the appended claims.