Patent Publication Number: US-7588271-B1

Title: Window security lock

Description:
FIELD OF THE INVENTION 
   The invention herein pertains to security locks and particularly pertains to window security locks which utilize a pivotal stop. 
   DESCRIPTION OF THE PRIOR ART AND OBJECTIVES OF THE INVENTION 
   In recent years with the increase in security awareness window security locks have become a more important feature of single hung, double hung and other type windows. Such locks are used to limit the window opening to prevent unauthorized persons from entering while simultaneously allowing sufficient ventilation. Such locks are generally mounted on the inside window jambs for manual operation as needed. Problems have arisen with prior window security locks in that the weather stripping seals placed for example on the lower window sash headers have inadvertently triggered the security locks, causing lock jams and breakage. Some conventional security locks have been broken due to high impact with the sash header, as when an excessive force is applied to open the sash. Other prior window security locks have failed due to insect, dust and debris infiltration. 
   Thus based on the disadvantages and problems associated with prior window security locks, the present invention was conceived and one of its objectives is to provide a window security lock which can be manufactured and installed in conventional single hung, double hung or other type window jambs at a reasonable price. 
   It is yet another objective of the present invention to provide a window security lock which will not inadvertently open during normal window sash movement. 
   It is still another objective of the present invention to provide a window security lock which has relatively few parts, with the main parts molded from a standard, durable polymeric material such as nylon. 
   It is also an objective of the present invention to provide a window security lock having a pivotable stop which is manually operated. 
   It is yet a further objective of the present invention to provide a window security lock with a stop having chamfered surfaces to provide for additional structural integrity and security. 
   Various other objectives and advantages of the present invention will become apparent to those skilled in the art as a more detailed description is set forth below. 
   SUMMARY OF THE INVENTION 
   The aforesaid and other objectives are realized by providing a window security lock having a pivotable stop contained within a rectangularly shaped housing. A resilient member in the form of a coil spring drives the stop outwardly from the housing through an opening located on the housing face. The face opening length is in excess of the exposed stop and a lip located on the stop inside the housing closes the opening and prevents infiltration of dirt, insects and debris during use. The stop defines a triangularly shaped slot for maintaining the spring and allowing spring rotation thereof as the stop moves from an extended to a retracted position within the housing. A pair of posts mounted on the inside of the housing anchors the lower end of the spring during operation of the stop. A pair of pivot pins located on the stop engage slots within each side of the housing to allow rotation of the stop. A cover positioned on one side of the housing permits assembly and disassembly of the housing by the use of small pegs on the housing cover which engage sockets in the housing. Chamfered surfaces on the stop provide structural integrity to the lock as the chamfered surfaces engage the inner housing walls when the stop is extended in the security mode. To extend the stop for security purposes finger pressure is applied to the front, exposed ridges of the stop, the stop is forced inwardly, compressing the resilient member. By then urging the stop upwardly while under pressure, the pivot pins bypass indents in the housing slots and allow upward vertical movement of the stop. Upon release, the stop pivots by resilient action of the spring and extends from the housing through the front opening. With the security lock mounted in the upper sash jamb, by raising the lower sash only a limited distance the stop is struck by the sash header and upward movement of the sash is terminated. The user thereby benefits by having a few inches of open window space while at the same time preventing unauthorized entry such as by a burglar through a greater window opening. 

   
     BRIEF DESCRIPTION OF THE DRAWINGS 
       FIG. 1  shows a typical inside building wall with a pair of double hung windows therein with a window security lock mounted on each window; 
       FIG. 2  illustrates the preferred form of the window security lock in a front left side perspective view as removed from the window and with a partial window sash header shown in ghost fashion; 
       FIG. 3  demonstrates a right side elevational view of the window security lock with the stop in an extended posture; 
       FIG. 4  pictures the window security lock as in  FIG. 3  but with the stop retracted; 
       FIG. 5  depicts the window security lock in a front, left side, perspective, exploded view; 
       FIG. 6  shows a rear elevational view of the window security lock; 
       FIG. 7  demonstrates a front elevational view of the window security lock with the stop retracted; 
       FIG. 8  features a left side elevational view of the window security lock with the cover removed, with the stop extended as mounted in a window jamb which is shown in ghost fashion; and 
       FIG. 9  illustrates the window security lock as in  FIG. 8  but without the window jamb and with the stop retracted. 
   

   DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT AND OPERATION OF THE INVENTION 
   For a better understanding of the invention and its operation, turning now to the drawings,  FIG. 1  illustrates preferred security window locks  10  as installed for closed double hung window  35  and partially opened double hung window  36  both mounted in wall  50  of a typical house or other building. Security lock  10  is preferably formed from conventional nylon. Glass reinforced nylon can be used for greater strength but is not preferred. As shown for window  36 , security window lock  10  is opened or extended to prevent full ascension of lower sash  37 . As featured, upper sash  38  may be rendered fixed such as by nails, screws or other hardware (not shown). Bottom sash  37  of window  36  shown in  FIG. 1  is raised approximately four inches and therefore security is provided by limiting the window opening thereby preventing burglars or other unauthorized persons from entering the building through window  36 , while at the same time allowing abundant fresh air to enter. 
   In  FIG. 2  a perspective view of preferred security window lock  10  is seen with stop  11  extended outwardly from face  14  of housing  12  to terminate upward motion of sash  37  by engaging window sash header  39  shown in dotted lines. As seen in  FIGS. 3 ,  4  and  6  housing  12  includes top fixed finger  17  and bottom flexible finger  16  which engage window jamb  40  during mounting of security lock  10 . Partial window jamb  40  as shown in dotted lines in  FIG. 8  is conventionally formed from vinyl or aluminum. 
   As further seen in  FIGS. 2 ,  3 ,  4  and  5 , housing  12  includes elongated slots  20 ,  20 ′ and L-shaped slots  21 ,  21 ′. Elongated slots  20 ,  20 ′ contain pivot pin  22  which is affixed to stop  11  whereas L-shaped slots  21 ,  21 ′ contain pivot pin  24  also affixed to stop  11  as shown in  FIG. 5 . Slots  20 ,  20 ′ include respectively indents  29 ,  29 ′ and L-shaped slots  21 ,  21 ′ respectively include indents  28 ,  28 ′ formed therein to assist in maintaining and controlling the movement of stop  11  within housing  12  during operation. 
   Stop  11  seen in  FIG. 5  includes wedge shaped lip  13  which engages the lower inner surfaces at opening  18  in housing face  14  when stop  11  is extended from housing  12 , shown for example in  FIGS. 2 and 8 . Lip  13  as illustrated prevents debris and insect entry into housing  12  through stop opening  18  as it closes opening  18  below extended stop  11  as seen in  FIG. 2 . Stop  11  further includes slot  15  for containing a resilient member such as coil spring  26  shown in  FIGS. 8 and 9 . Slot  15  is somewhat triangularly shaped to permit movement of coil spring  26  positioned therein. As shown in  FIGS. 5 ,  8  and  9  housing  12  includes posts  27 ,  27 ′ to assist in maintaining the lower end of spring  26  which rotates in slot  15  as stop  11  pivots from an open position ( FIG. 8 ) to a closed position ( FIG. 9 ). Triangularly shaped slot  15  thus allows space for coil spring  26  to rotate and prevents binding of coil spring  26  during operation of stop  11 . 
   As seen in  FIG. 5  stop  11  includes chamfered surfaces  31  and  32  which engage respectively, inner housing surfaces  33  and  34  when stop  11  is extended as seen in  FIG. 8 . This engagement with housing  12  provides strength and integrity to window security lock  10 . Should lower sash  37  be forcibly opened impacting stop  11 , chamfered surfaces  31  and  32  braced against respectively inner housing surfaces  33 ,  34  provide a solid support to prevent breakage of window lock  10 . 
   Many standard single and double hung windows include a resilient seal (not seen) on the top inside of lower sash header such as lower sash header  39  shown in  FIG. 1 . This seal is provided to prevent outside air infiltration and consequently may contact face  14  ( FIG. 7 ) of window security lock  10  when lower sash  37  is raised. Thus to prevent interference with security lock  10  by such seals, stop  11  is mounted within housing  12  to be slightly depressed as seen in  FIGS. 4 and 9 . To utilize window lock  10  the user applies finger pressure to ridges  25  of retracted stop  11  as seen in  FIG. 4  when window lock  10  is closed to drive stop  11  slightly inwardly and by pushing stop  11  upwardly (towards fixed finger  17 ), pivot pin  24  bypasses indent  28 ′ of slot  21 ′ and pivot pin  22  bypasses indent  29 ′ of slot  20 ′. Stop  11  thus moves upwardly and spring  26  can then expand and force stop  11  through opening  18  as shown in  FIGS. 2 and 3 . Pivot pin  24  is now at the upper ends of L-shaped slots  21 ,  21 ′ as shown in  FIGS. 2 and 3 . When so opened stop  11  will be available to engage window sash header  39  as seen on window  36  in  FIG. 1  to limit the window opening. Indents  28 ,  28 ′,  29  and  29 ′ prevent inadvertent operation of security lock  10  by contact with a sash header seal during normal opening of the window sash. 
   The illustrations and examples provided herein are for explanatory purposes only and are not intended to limit the scope of the appended claims. As an example of an obvious modification as may be made by a skilled artisan, pivot pins  22 , and slots  20 ,  20 ′,  21 ,  21 ′ could be reversed, i.e. pivot pins  22 ,  24  could be located on housing  12  and cover  19  and slots  20   21 ′ could be positioned in stop  11  without changing the function or advantages of window security lock  10 . Various other changes could also be made.