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CROSS-REFERENCE TO RELATED APPLICATIONS 
     Not Applicable. 
     FEDERAL SPONSORSHIP 
     Not Applicable 
     JOINT RESEARCH AGREEMENT 
     Not Applicable 
     TECHNICAL FIELD 
     This invention pertains generally to door barricades. More particularly, the invention pertains to a device that quickly and easily installs on a classroom door allowing a school teacher to quickly restrict access into a classroom. The restraint device is particularly well suited for restricting the opening of a classroom door that does not have conventional door handle locks. 
     BACKGROUND 
     Over the years, classrooms have been constructed having doors to isolate the classroom from adjacent hallways and other portion of the building. At times there has been a desire to avoid door handles having the ability to lock the handle from the inside of the classroom. Further, previously it was desirable to make the classrooms accessible from the hallway to eliminate the possibility of restricting access into the classroom. Thus, many school building walls and doors have been constructed to achieve these desires. However, recent social events has generated a need to allow teachers the ability to barricade and restrict access into their classrooms. Prior devices to barricade a classroom door include limitations that do not allow for the rapid placement and removal of the barricade device. For example, prior attempts have been made to barricade a classroom door without a door knob locking mechanism, however these devices have required mounting of the device onto a portion of the door or doorjamb. Other attempts have required structural modifications to the floor or door jamb. The shortcomings of other prior classroom door restraints also increases the likelihood that an intruder could overcome the restraint through force or easy removal. 
     SUMMARY 
     Embodiments according to aspects of the invention allow a school teacher to expeditiously restrict access into a classroom in the event of a lockdown or other impending need to restrict entry into the classroom. Embodiments of the door barricade apparatus of the present invention include a base, extensions and a door pressing member. The base has a first end including a door engaging member extending vertically from the base, a mid-section of the base has a thickness dimension less than a spacing between a floor and a bottom edge of a door, and a support section of the base terminates at a second end of the base that opposes the first end of the base. The extensions extend tangentially outward from the support section of the base and are adapted to engage a door jamb and adjacent wall section. The pressing member is coupled to the support section and is adaptable to apply a force to the door to thereby sandwich the door between the door engaging member and a portion of the pressing member. 
     Embodiments of the door barricade apparatus in accordance with aspects of the invention further include a support member through which a threaded rod rotates. The threaded rod has a first end aligned towards the door engaging member and has a second end extending in a direction opposite the door engaging member and terminating in a knob. The first end of the threaded rod may further include a pliant stop coupled to the first end of the threaded rod. 
     Expeditious barricading of a classroom door may be accomplished in accordance with the present invention. The method of barricading a classroom door and restricting the door from rotating out away from the classroom can be accomplished by positioning a door barricade apparatus of the present invention in alignment with a door, doorjamb, and adjacent wall section and then engaging the door barricade apparatus with the door. In this manner a teacher may quickly and expeditiously restrict entry into the classroom. 
     The method includes using a door barricade apparatus comprised of a base, extension members and a pressing member. The base has a first end including a door engaging member extending vertically from the base, a mid-section of the base having a thickness dimension less than a spacing between a floor and a bottom edge of the door, and a support section terminating at a second end of the base that opposes the first end of the base. The extensions extending tangentially outward from the support section of the base and are adapted to engage the door jamb and the adjacent wall section. The pressing member couples to the support section and is adaptable to apply a force to the door to thereby sandwich the door between the door engaging member and a portion of the pressing member. The pressing member includes a support member through which a threaded rod rotates; the threaded rod having a first end aligned towards the door engaging member and having a second end extending in a direction opposite the door engaging member and terminating in a knob. The first end of the threaded rod further includes a pliant stop coupled to the first end of the threaded rod. The method may further include the step of engaging the pliant stop against the door. The step of positioning the door barricade apparatus may further include aligning at least one of the extensions to overlap the door jamb and wall. 
     The accompanying drawings, which are incorporated in and constitute a portion of this specification, illustrate embodiments of the invention and, together with the detailed description, serve to further explain the invention. The embodiments illustrated herein are presently preferred; however, it should be understood, that the invention is not limited to the precise arrangements and instrumentalities shown. For a fuller understanding of the nature and advantages of the invention, reference should be made to the detailed description in conjunction with the accompanying drawings. 
    
    
     
       DESCRIPTION OF THE DRAWINGS 
       In the various figures, which are not necessarily drawn to scale, like numerals throughout the figures identify substantially similar components. 
         FIG. 1  is a front perspective view of an embodiment of a door restraint apparatus of the present invention; 
         FIG. 2  is a left side perspective view of an embodiment of a door restraint apparatus of the present invention; 
         FIG. 3  is a right side perspective view of an embodiment of a door restraint apparatus of the present invention; 
         FIG. 4  is a partial perspective view of an embodiment of a door restraint apparatus of the present invention shown positioned and oriented to a door and door jamb inside a classroom; and 
         FIG. 5  is a partial perspective view of an embodiment of a door restraint apparatus of the type shown in  FIG. 4  positioned and oriented to a door and door jamb and shown from outside the classroom. 
     
    
    
     DETAILED DESCRIPTION 
     The following description provides detail of various embodiments of the invention, one or more examples of which are set forth below. Each of these embodiments are provided by way of explanation of the invention, and not intended to be a limitation of the invention. Further, those skilled in the art will appreciate that various modifications and variations may be made in the present invention without departing from the scope or spirit of the invention. By way of example, those skilled in the art will recognize that features illustrated or described as part of one embodiment, may be used in another embodiment to yield a still further embodiment. Thus, it is intended that the present invention also cover such modifications and variations that come within the scope of the appended claims and their equivalents. 
     The apparatus of the present invention is particularly well suited for quickly restricting access into a classroom. The apparatus may be installed and removed simply and does not require modification to an existing classroom door or doorjamb. Further, those skilled in the art will appreciate that the door barricade apparatus in accordance with the present invention may withstand significant force attempts to overcome the restraining apparatus. The door restraint  10  of the present invention generally includes a base  30 , door engaging member  32 , door pressing or clamping member  40 , and door jamb engaging extensions  38 . 
     With reference to  FIGS. 1-3 , embodiments according to aspects of the invention will be described in conjunction with the door restraint  10 . The base  30  has a first end including the door engaging member  32  extending vertically from the base  30 , a mid-section  34  of the base having a thickness dimension less than a spacing between a floor and a bottom edge of a door  14 , and a support section  36  terminating at a second end of the base  30 . The support section  36  opposes the first end of the base  30  and includes extensions  38  extending tangentially outward from the support section  36  of the base  30 . The extensions  38  are symmetric and adapted to engage either side of a door jamb  16  and adjacent wall section  18 ; independent of the direction the door swings out from the door jamb  16 . 
     The pressing member  40  is coupled to the support section  36  and adaptable to apply a force to the door  14  to thereby fix the door restraint  10  in place and sandwich the door  14  between the door engaging member  32  and a portion of the pressing member  40 . In an embodiment of the invention the pressing member  40  includes a support member defining the support section  36  of the base. A threaded rod  42  extends through the support member in threaded holes to allow rotation of the rod  42 . Hex nuts may be position on either side of the support member to restrict rotation of the threaded rod  42 . The threaded rod has a first end aligned towards the door engaging member  32  and has a second end extending in a direction opposite the door engaging member and terminating in a knob  44 . The first end of the threaded rod  42  may further include a pliant stop or rubber tip  46  coupled to the first end of the threaded rod  42 . Those skilled in the art will appreciate that in order to reduce the weight of the door restraint  10 , while maintaining the rigidity of the apparatus, the support member may have a hollow section  48  extending from one side to the other. Also, the support member and pressing member could be constructed similar to a toggle clamp and mounted to the base  30 . Further, in embodiments of the invention felt  60  may be applied to the door engaging member  32 , felt  62  may be applied to a top side of the mid-section  34 , felt  64  may be applied to the bottom of base  30 , and felt  66  may be applied to the door engaging side of the extensions  38 . 
     Having described the constructional features of the door restraint  10  of the present invention, it&#39;s use will be described in greater detail. With reference to  FIGS. 4 and 5  door  14  is pivoted on hinges far enough away from the door jamb  16  to allow the mid-section  34  of the base  30  to be slid under the door  14  such that the door engaging member  32  is positioned on the outside of the door and the pressing member  40  is adjacent the inside of the door. The door is then closed and the door restraint  10  is slid towards the door jamb  16  so that the extension  38  extends past the door jamb and a portion of the wall section  18 . Once the door restraint is positioned, the knob  44  is turned in a direction so that the threaded rod  42  rotates closer to the door  14  and until the pliant stop  46  firmly engages with the door  10 . When an attempt is made to open the door, the extension engages the jamb  16  and wall section  18  and is capable of withstanding significant outward forces against the door. 
     These and various other aspects and features of the invention are described with the intent to be illustrative, and not restrictive. This invention has been described herein with detail in order to comply with the patent statutes and to provide those skilled in the art with information needed to apply the novel principles and to construct and use such specialized components as are required. It is to be understood, however, that the invention can be carried out by specifically different constructions, and that various modifications, both as to the construction and operating procedures, can be accomplished without departing from the scope of the invention. Further, in the appended claims, the transitional terms comprising and including are used in the open ended sense in that elements in addition to those enumerated may also be present. Other examples will be apparent to those of skill in the art upon reviewing this document.

Summary:
An apparatus and method for efficiently restricting access to a classroom is described. The apparatus is particularly well suited for a school teacher needing to quickly barricade the classroom door and restrict access into the classroom. The apparatus of the present invention is efficiently slid under the door and tightened to the door and jamb to restrain the opening of the door.