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You are an expert at summarizing long articles. Proceed to summarize the following text: 
CROSS REFERENCE TO RELATED APPLICATION 
     This is a utility application based upon provisional application Ser. No. 60/205,398 filed May 19, 2000 which is incorporated herewith by reference for which priority is claimed. 
    
    
     BACKGROUND OF THE INVENTION 
     In a principal aspect the present invention relates to a plug lock and more particularly, a flush mounted plug lock or panel lock which may be snapped into a recess of a panel door and which includes a projecting bolt cooperative with a strike to retain the door in a closed and locked position. 
     Various prior art patents disclose panel locks which are used to close and lock panels such as cabinet panels, locker door panels and the like. For example, U.S. Pat. No. 4,882,919 for a Flush Mounted Panel Lock Construction discloses such a mechanism. Other patents disclosing such mechanisms include U.S. Pat. No. 6,023,953 for a Slam Latch With Opposing Slides and U.S. Pat. No. 4,578,968 for a Flush Mount Lock Assembly. Typically, such locks include a pivotal push plate which is mounted for rotation about a pin or axis in the lock housing. A rotatable key actuated plug assembly actuates a lock plate provided for engagement with the push plate to lock or release the push plate. When the push plate is released pivoting action of the push plate effects release of a bolt. When the plug assembly is in the locked position, the push plate may not be pivoted and, thus, the bolt may not be disengaged from a strike. 
     SUMMARY OF THE INVENTION 
     Briefly, the present invention comprises a panel lock which includes a housing with a cavity having a push plate pivotally mounted therein for engagement with a slidable bolt upon pivotal movement of the push plate. A rotatable plug assembly in the housing includes a plug head with a partially circumferential flange that may be aligned over ribs in the push plate to thereby engage and hold the push plate in the housing and preclude pivotal movement of the push plate. The plug head may be rotated to a position where the flange is removed from engaging the push plate ribs so that the push plate may be pivoted about its mounting axis to release the bolt from a strike. 
     Thus, it is an object of the invention to provide an improved panel lock construction. 
     It is a further object of the invention to provide a panel lock construction having a minimum number of parts wherein a pivotal push plate may be engaged and locked by a rotatable key actuated plug lock assembly mounted in the housing for the lock. 
     Yet another object of the invention is to provide an inexpensive, yet rugged and durable, panel lock. These and other objects, advantages and features of the invention will be set forth in the detailed description which follows. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     In the detailed description which follows, reference will be made with the drawing, comprised of the following figures: 
     FIG. 1 is an exploded isometric view of the panel lock; 
     FIG. 2 is a side elevation of the assembled panel lock depicted in FIG. 1; 
     FIG. 3 is a cross sectional view of the panel lock of FIG. 2 taken along the line  3 — 3  in FIG. 2; 
     FIG. 4 is a top or front plan view of the panel lock; 
     FIG. 5 is a cross-sectional view of the panel lock of FIG. 4 taken along the line  5 — 5 ; 
     FIG. 6 is a sectional view of the panel lock of FIG. 4 taken along the line  6 — 6 ; 
     FIG. 7 is an isometric view of the plug for the panel lock; 
     FIG. 8 is an isometric view of the panel lock with the push plate moved to the bolt unlocking position; 
     FIG. 9 is a plan view of the panel lock with the plug in the locked position; 
     FIG. 10 is a cross-sectional view of the panel lock of FIG. 9 taken along the line  10 — 10 ; and 
     FIG. 11 is an exploded isometric view of an alternate construction; and 
     FIG. 12 is an isometric view of the construction of FIG. 11 assembled. 
    
    
     DESCRIPTION OF THE PREFERRED EMBODIMENT 
     Referring to the Figures, the panel lock includes a housing  10  with a recess or cavity  12 . The chamber or cavity  12  includes spaced, opposed, generally parallel sides or sidewalls  14  and  16 . Each of the sides  14  and  16  include pivot pin openings such as pin opening  22  for receipt of a mounting pin  24  which is provided to pivotally mount a push plate  26  having a configuration generally congruent with the opening of cavity  12 . A slidable bolt  28  is mounted in the cavity  12  and is biased by a spring  30  which fits into a bore  32  in bolt  28  to bias the bolt  28  outwardly from cavity  12  through a lateral or side opening  34  in the wall  14  of housing  10 . 
     The housing  10  further includes a generally cylindrical bore or counterbore cavity  18  for receipt of a rotatable plug assembly or lock plug  20 . The plug  20  is rotatably mounted in the counterbore cavity  18  and includes a plug head  36  which has opposite, outwardly extending arcuate sides  38  and  40  comprising a flange. The plug head  36  further includes opposite flat sides  42  and  44  connecting the arcuate sides  38 ,  40 . In other words, the plug head  36 , which ordinarily may be circular in shape, has sectors removed from the circular plug head  36  resulting in flat sides  42  and  44  that connect the partial peripheral, flange sides or sections  38  and  40 . 
     The push plate  26  includes a generally circular counterbore  46  with first and second underlying spaced, opposite side ribs or flanges  48  and  50  provided on the bottom side of the push plate  26  in the counter bore  46 . Push plate  26  further includes a cam  51  on its underside which may be engaged with an inclined follower surface  52  of the bolt  28  so that when the push plate  26  is pivoted by pushing on a push surface  41  about the pin  24 , the cam  51  will engage the follower surface  52  and translate the bolt  28  inwardly into housing  10  in the direction of the arrow in FIG. 3 against the biasing force of the biasing member or spring  30 . 
     An important feature of the invention relates to the construction of the plug head  36  and the opening  46  through the face plate  26 . Thus, the ribs  48  and  50  of the push plate  26  underlie the arcuate flanges  38  and  40  of the plug head  36  of the plug  20  whenever the plug  20  has been rotated about a plug axis  45  to a locked position such as indicated in FIG.  5 . Referring to FIG.  9  and FIG. 10, the ribs  48  and  50  underlie the flanges or flange sections  38  and  40  of plug head  36  when the rotatable plug assembly or lock plug  20  is rotated to the locked position and the push plate  26  is in the locked position with respect to the bolt  28 . In order to release the push plate  26  and permit rotation thereof about the pin  24 , a key  49  is inserted through a keyhole slot  58  to align tumblers  47  of the plug  20  permitting rotation of the rotatable plug assembly. The plug  20  is thus released from locking engagement with the bore  18  and then may be rotated to the position depicted in FIG.  4 . When in this position as also depicted in FIG. 11, the ribs  48  and  50  no longer engage with the flanges  38  and  40 . The push plate  26  may then be pushed or pivoted as depicted in FIG. 8 to drive the bolt  28  to the open position. 
     FIGS. 11 and 12 depict an alternative embodiment wherein a faceplate  80  may be pulled to release a bolt. Like components of the embodiments have like numbers. The embodiment of FIGS. 11-12 differs from that of FIGS. 1-10 inasmuch as plate  80  is shortened so that it may be pulled rather than pushed to pivot and thereby move the bolt  28 . Thus a finger cavity  84  is provided in the housing  10  so that an operator may engage an edge  86  of pivotal, shortened plate or pull  80 . 
     It is possible to alter the construction of the cooperating flanges associated with the plug head  36  and the opening  46  of the face plate  26  to accomplish the described result. Various other modifications may be made to the panel lock without departing from the spirit and scope of the invention. The invention is therefore to be limited only by the following claims and equivalents thereof.

Summary:
A panel lock includes a housing with a pivotal face plate arranged to engage a bolt upon pivotal movement of the face plate. A rotatable plug assembly may be rotated between a locking and unlocking position to restrain or release the push plate.